Polishing pad produced by lamination manufacturing process
阅读说明:本技术 由积层制造工艺所生产的研磨垫 (Polishing pad produced by lamination manufacturing process ) 是由 R·巴贾杰 D·莱德菲尔德 M·C·奥里拉利 B·福 A·J·康纳 J·G·方 M·科尔 于 2015-10-16 设计创作,主要内容包括:本公开的实施例是关于具有可调谐化学特性、材料特性及结构特性的高级研磨垫,及制造所述研磨垫的新方法。根据本公开的一或多个实施例,已发现具有改善特性的研磨垫可由诸如三维(3D)打印工艺的积层制造工艺来产生。因此,本公开的实施例可提供具有离散特征及几何形状、由至少两种不同材料形成的高级研磨垫,所述不同材料包括官能性聚合物、官能性寡聚物、反应性稀释剂及固化剂。举例而言,该高级研磨垫可通过自动化依序沉积至少一种树脂前体组成物,随后以至少一个固化步骤而由多个聚合物层形成,其中各层可表示至少一种聚合物组成物和/或不同组成物的区域。(Embodiments of the present disclosure relate to advanced polishing pads with tunable chemical, material, and structural properties, and new methods of manufacturing the same. In accordance with one or more embodiments of the present disclosure, it has been discovered that polishing pads having improved characteristics may be produced by additive manufacturing processes, such as three-dimensional (3D) printing processes. Accordingly, embodiments of the present disclosure may provide advanced polishing pads having discrete features and geometries formed from at least two different materials, including functional polymers, functional oligomers, reactive diluents, and curing agents. For example, the advanced polishing pad may be formed from multiple polymer layers by automated sequential deposition of at least one resin precursor composition followed by at least one curing step, wherein each layer may represent at least one polymer composition and/or regions of different composition.)
1. A polishing pad having a polishing surface configured for polishing a surface of a substrate, the polishing pad comprising:
a plurality of abrasive elements disposed in a pattern relative to the abrasive surface, wherein each abrasive element is formed from a first polymeric material and surfaces of the plurality of abrasive elements form at least a portion of the abrasive surface; and
a base layer disposed between each of the plurality of polishing elements and the support surface of the polishing pad, the base layer comprising a second polymeric material, wherein:
the first polymeric material has a first E '30/E' 90 ratio and the second polymeric material has a second E '30/E' 90 ratio, the second E '30/E' 90 ratio being different than the first E '30/E' 90 ratio,
the first polymeric material is formed from a first drop formulation comprising one or more first precursor components having a glass transition temperature (Tg) of greater than or equal to 40 ℃ and one or more second precursor components having a glass transition temperature of less than 40 ℃,
the amount of the one or more first precursor components in the first drop formulation is greater than the amount of the one or more second precursor components in the first drop formulation,
the second polymeric material is formed from a second droplet formulation comprising the one or more first precursor components and the one or more second precursor components,
the amount of the one or more second precursor components in the second droplet formulation is greater than the amount of the one or more first precursor components in the second droplet formulation,
the first and second precursor components are selected from the group consisting of monomers, oligomers, and functional polymers, and
the first polymeric material of the plurality of abrasive elements and the second polymeric material of the substrate layer are co-mixed and chemically bonded together at one or more boundaries thereof.
2. The polishing pad of claim 1, wherein a region including one or more polishing elements of the plurality of polishing elements disposed on the base layer has a third E '30/E' 90 ratio, the third E '30/E' 90 ratio being different from the first and second E '30/E' 90 ratios when measured by loading the region in a direction perpendicular to the polishing surface.
3. The polishing pad of claim 1, wherein the first E '30/E' 90 ratio is greater than about 6.
4. The polishing pad of claim 1, wherein the first polymeric material and the second polymeric material each comprise a material selected from the group consisting of: polyamides, polyetherketones, polyethers, polyethersulfones, polyetherimides, polyimides, polysiloxanes, polysulfones, polyphenyls, polyphenylene sulfides, polystyrenes, polyacrylonitriles, polymethyl methacrylates, urethane acrylates, polyester acrylates, polyether acrylates, epoxy acrylates, melamines, polysulfones, Acrylonitrile Butadiene Styrene (ABS), halogenated polymers, block copolymers, and copolymers of the foregoing polymeric materials.
5. The polishing pad of claim 1, wherein an interface region formed at the one or more boundaries between the plurality of polishing elements and the base layer comprises a compositional gradient from the first polymer material to the second polymer material.
6. The polishing pad of claim 1, wherein the base layer further comprises the first polymeric material, and wherein a material composition ratio of the first polymeric material to the second polymeric material in the base layer is less than 1.
7. The polishing pad of claim 7, wherein each of the plurality of polishing elements further comprises the second polymeric material, and a material composition ratio of the first polymeric material to the second polymeric material in the plurality of polishing elements is greater than 1.
8. The polishing pad of claim 1, wherein the first E '30/E' 90 ratio is greater than the second E '30/E' 90 ratio.
9. A polishing pad having a polishing surface configured for polishing a substrate, the polishing pad comprising:
a plurality of abrasive elements comprising a first polymeric material, wherein one or more first surfaces of the plurality of abrasive elements form the abrasive surface; and
a base layer having a plurality of first regions, one of the plurality of first regions disposed between a polishing element of the plurality of first polishing elements and a support surface of the polishing pad, the base layer comprising a mixture of the first polymeric material and the second polymeric material, wherein:
the first polymeric material has a first storage modulus and the mixture of the first polymeric material and the second polymeric material has a second storage modulus,
the first storage modulus is greater than the second storage modulus,
the first polymeric material is formed from one or more first precursor components having a glass transition temperature (Tg) greater than or equal to 40 ℃, and the second polymeric material is formed from one or more second precursor components having a glass transition temperature (Tg) less than 40 ℃,
the first and second precursor components are selected from the group consisting of monomers, oligomers, and functional polymers, and
the base layer includes a greater volume percentage of the second polymeric material than the first polymeric material.
10. The polishing pad of claim 9, wherein:
the first polymeric material has a first E '30/E' 90 ratio and the mixture has a second E '30/E' 90 ratio, the second E '30/E' 90 ratio being different than the first E '30/E' 90 ratio, and
a region comprising one or more of the plurality of abrasive elements disposed on the substrate layer has a third E '30/E' 90 ratio that is different from the first and second E '30/E' 90 ratios when measured by loading the region in a direction perpendicular to the abrasive surface.
11. The polishing pad of claim 10, wherein the first E '30/E' 90 ratio is greater than 6.
12. The polishing pad of claim 9, wherein the plurality of polishing elements each comprise a plurality of sequentially deposited first polymer layers formed from a plurality of droplets of a first droplet composition, and the base layer comprises a plurality of sequentially deposited second polymer layers formed from a mixture of the plurality of droplets of the first droplet composition and droplets of a second droplet composition, wherein the second droplet composition comprises a greater amount by weight of the one or more second resin precursor components than the first droplet composition.
13. The polishing pad of claim 9, wherein the first and second polymeric materials each comprise a material selected from the group consisting of: polyamides, polyetherketones, polyethers, polyethersulfones, polyetherimides, polyimides, polysiloxanes, polysulfones, polyphenyls, polyphenylene sulfides, polystyrenes, polyacrylonitriles, polymethyl methacrylates, urethane acrylates, polyester acrylates, polyether acrylates, epoxy acrylates, melamines, polysulfones, Acrylonitrile Butadiene Styrene (ABS), halogenated polymers, block copolymers, and copolymers of the foregoing polymeric materials.
14. The polishing pad of claim 9, wherein an interface between one or more polishing elements of the plurality of polishing elements and the base layer comprises a compositional gradient from the first polymeric material to the mixture of the first polymeric material and the second polymeric material.
15. The polishing pad of claim 9, wherein the first polymer material of the plurality of polishing elements and the second polymer material of the base layer are chemically bonded together at their boundaries.
16. A polishing pad having a polishing surface configured for polishing a surface of a substrate, the polishing pad comprising:
a plurality of abrasive elements disposed in a pattern relative to the abrasive surface, wherein each abrasive element comprises a plurality of sequentially deposited first polymer layers comprising a first polymer material, and at least one of the plurality of sequentially deposited first polymer layers in each of the first abrasive elements forms a portion of the abrasive surface; and
a base layer having a plurality of first portions respectively disposed between respective polishing elements of the plurality of first polishing elements and a support surface of the polishing pad, wherein:
the base layer comprises a second polymeric material,
the first polymeric material has a first tan and the second polymeric material has a second tan, the second tan being different from the first tan,
the first polymeric material is formed by curing a first drop of the composition and the second polymeric material is formed by curing a second drop of the composition,
the first drop composition comprises a greater amount of a first resin precursor component than the second drop composition,
the second droplet composition includes a greater amount of a second resin precursor component than the first droplet composition,
the first resin precursor component has a glass transition temperature (Tg) greater than 40 ℃ and the second resin precursor component has a glass transition temperature (Tg) less than or equal to 40 ℃,
the first and second precursor components are selected from the group consisting of monomers, oligomers, and functional polymers; and
the first polymeric material of the plurality of abrasive elements and the second polymeric material of the substrate layer are co-mixed and chemically bonded together at one or more boundaries thereof.
17. The polishing pad of claim 16, wherein:
the first polymeric material has a first E '30/E' 90 ratio and the second polymeric material has a second E '30/E' 90 ratio, the second E '30/E' 90 ratio being different than the first E '30/E' 90 ratio,
at least a region of the polishing pad has a third E '30/E' 90 ratio, the third E '30/E' 90 ratio being different from the first and second E '30/E' 90 ratios when measured by loading the region of the polishing pad in a direction perpendicular to the polishing surface, an
The region of the polishing pad includes a subset of the plurality of the first polishing elements and a portion of the base layer disposed between each of the first polishing elements in the subset of the first polishing elements and the support surface.
18. The polishing pad of claim 16, wherein the first and second polymeric materials each comprise a material selected from the group consisting of: polyamides, polyetherketones, polyethers, polyethersulfones, polyetherimides, polyimides, polysiloxanes, polysulfones, polyphenyls, polyphenylene sulfides, polystyrenes, polyacrylonitriles, polymethyl methacrylates, urethane acrylates, polyester acrylates, polyether acrylates, epoxy acrylates, melamines, polysulfones, Acrylonitrile Butadiene Styrene (ABS), halogenated polymers, block copolymers, and copolymers of the foregoing polymeric materials.
19. The polishing pad of claim 16, wherein an interface formed between the first and second polymeric materials comprises a concentration gradient formed by varying a material composition ratio of the first and second droplet compositions in the formed first and second polymeric layers on either side of the interface.
20. The polishing pad of claim 16, wherein:
the base layer further comprises the first polymeric material and the amount of the first polymeric material to the second polymeric material in the base layer has a material composition ratio of less than 1, an
The first abrasive elements each further comprise the second polymeric material, and a ratio of the amount of the first polymeric material to the second polymeric material in the first abrasive elements is greater than 1.
Technical Field
Embodiments disclosed herein relate generally to abrasive articles and methods of making abrasive articles for use in abrasive processes. More particularly, embodiments disclosed herein relate to polishing pads produced by processes that result in improved polishing pad characteristics and performance, including tunable performance.
Background
Chemical Mechanical Polishing (CMP) is a conventional process used in many different industries to planarize substrate surfaces. In the semiconductor industry, uniformity of polishing and planarization is becoming increasingly important as device feature sizes continue to shrink. During the CMP process, a substrate, such as a silicon wafer, is mounted on a carrier head with the device surface placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to urge the device surface against the polishing pad. A polishing liquid, such as a slurry with abrasive particles, is typically supplied to the surface of the moving polishing pad and the polishing head. The polishing pad and head apply mechanical energy to the substrate, while the pad also helps control the transport of slurry that interacts with the substrate during the polishing process. Since polishing pads are typically made of viscoelastic polymeric materials, the mechanical properties of the polishing pad (e.g., elasticity, rebound, hardness, and stiffness) and CMP processing conditions have a significant impact on CMP polishing performance on both the IC die scale (micro/nanoscopic) and the wafer or global scale (macro). For example, CMP process forces and conditions (such as pad compression, pad rebound, friction, and temperature changes during processing) and abrasive aqueous slurry chemistry will affect the polishing pad characteristics and thus the CMP performance.
The chemical mechanical polishing process performed in the polishing system will typically include multiple polishing pads performing different portions of the overall polishing process. The polishing system generally includes a first polishing pad disposed on a first platen, the first polishing pad producing a first material removal rate and a first surface brightness and a first flatness on the substrate surface. The first polishing step is commonly referred to as a rough polishing step and is typically performed at a higher polishing rate. The system will also typically include at least one additional polishing pad disposed on the at least one additional platen that produces a second material removal rate and a second surface brightness and planarity on the substrate surface. The second grinding step, commonly referred to as the fine grinding step, is typically performed at a lower rate than the coarse grinding step. In some configurations, the system further includes a third polishing pad disposed on the third platen, the third polishing pad producing a third material removal rate and a third surface brightness and flatness on the substrate surface. The third grinding step is commonly referred to as a material cleaning or polishing step. The multi-pad polishing process may be used in a multi-step process where each pad has different polishing properties and the substrate is subjected to progressively finer polishing or polishing properties are adjusted to compensate for different layers encountered during polishing, such as metal lines under the oxide surface.
During each CMP processing step, the polishing pad is exposed to compression and rebound cycles, heating and cooling cycles, and abrasive slurry chemistry. Eventually, the polishing pad becomes worn or "glazed" after polishing a certain number of substrates, and subsequently needs to be replaced or refurbished.
Conventional polishing pads are typically made by molding, casting, or sintering a polymeric material comprising a polyurethane material. In the case of molding, the polishing pads can be made one at a time, for example, by injection molding. In the case of casting, the liquid precursor is cast and cured into a cake, which is subsequently cut into individual pads. These shims may then be machined to final thickness. Pad surface features including grooves to facilitate slurry transport may be machined into the abrasive surface or formed as part of an injection molding process. These methods of manufacturing polishing pads are expensive and time consuming, and often produce non-uniform polishing results due to difficulties in producing and controlling the dimensions of the pad surface features. Non-uniformity is becoming increasingly important as the dimensions of IC dies and features continue to shrink.
Current mat materials and methods of producing the mat materials limit the manipulation and fine control of bulk mat properties, such as storage modulus (E') and loss modulus (E "), which play an important role in mat performance. Thus, uniform CMP requires a pad material and surface features, such as grooves and trenches, with a predictable and finely controlled balance of storage modulus E' and loss modulus E ", which is further maintained over a CMP processing temperature range of, for example, about 30 ℃ to about 90 ℃. Unfortunately, conventional pad production via typical bulk polymerization and casting and molding techniques provides only a small amount of control of pad properties (e.g., modulus) because the pad is a random mixture of phase separated macro-molecular domains that are subject to intramolecular repulsive and attractive forces and entanglement of variable polymer chains. For example, the presence of phase separated micro and macro domains in the bulk pad can result in additive combinations of nonlinear material responses, such as hysteresis in the storage modulus E' over multiple heating and cooling cycles that typically occur during CMP processing of multiple batches of substrates, which can lead to polishing non-uniformities and unpredictable performance between different batches of substrates.
Due to the drawbacks associated with conventional polishing pads and methods of making the same, there is a need for new polishing pad materials, and new methods of making polishing pads that provide control over pad feature geometry and fine control over pad material, chemical, and physical properties. These improvements are expected to result in improved polishing uniformity, both at the micro-level and the macro-level (such as across the substrate).
Disclosure of Invention
Embodiments of the present disclosure may provide a polishing pad having a polishing surface configured to polish a surface of a substrate, the polishing pad comprising: a plurality of first polishing elements each comprising a plurality of first polymer layers, wherein at least one of the plurality of first polymer layers forms a polishing surface; and one or more second polishing elements each comprising a plurality of second polymer layers, wherein at least a region of each of the one or more second polishing elements is disposed between at least one of the plurality of first polishing elements and the support surface of the polishing pad. In some configurations, the plurality of first polymer layers includes a first polymer composition and the plurality of second polymer layers includes a second polymer composition. The first abrasive element can include a first material and the second abrasive element can include a second material, wherein the first material is formed from the first drop composition and the second material is formed from the second drop composition. In some embodiments, the second droplet composition may include a greater amount of resin precursor composition material than the first droplet composition, and the glass transition temperature of the resin precursor composition material may be less than or equal to about 40 ℃. In some embodiments, the first drop comprises a greater amount of oligomer and resin precursor composition material than the second drop composition, wherein the oligomer and resin precursor composition material has a functionality greater than or equal to 2. In some embodiments, the first droplet composition comprises an oligomer having a functionality of greater than or equal to 2 and a resin precursor composition material, and the second droplet composition comprises a resin precursor composition material having a functionality of less than or equal to 2.
Embodiments of the present disclosure may further provide a polishing pad having a polishing surface configured to polish a surface of a substrate, comprising a plurality of first polishing elements each comprising a plurality of first polymer layers comprising a first polymer material, wherein at least one of the plurality of first polymer layers forms the polishing surface; and a base region disposed between at least one of the plurality of first polishing elements and the polishing pad support surface, wherein the base region comprises a plurality of layers, each layer comprising a plurality of cured droplets of a first resin precursor composition material and a plurality of cured droplets of a second resin precursor composition material.
Embodiments of the present disclosure may further provide a method of forming an abrasive article, the method comprising dispensing a first drop of a first liquid onto a surface of a portion of an abrasive body, wherein the surface comprises a first material formed by curing an amount of the first liquid; and exposing the dispensed first drop of the first liquid to electromagnetic radiation for a first period of time to only partially cure the material within the first drop, wherein exposing the dispensed first drop of the first liquid occurs after a second period of time elapses and the second time begins when the first drop is disposed on the surface. The first drop may include a urethane acrylate, a surface cure photoinitiator, and a bulk cure photoinitiator, wherein the bulk cure photoinitiator includes a material selected from the group consisting of benzoin ethers, benzyl ketals, acetophenone ketones, alkyl phenones, and phosphine oxides, and the surface cure photoinitiator includes a material selected from the group consisting of benzophenone compounds and thioxanthone compounds.
Embodiments of the present disclosure may further provide a method of forming an abrasive article, comprising: dispensing an amount of a first liquid onto a surface of a portion of an abrasive body, wherein the surface comprises a first material formed by: curing the quantity of the first liquid and exposing the dispensed first quantity of the first liquid to electromagnetic radiation generated from a source for a first period of time, thereby only partially curing the first quantity of the first liquid, and exposing the dispensed first quantity of the first liquid is performed after a second period of time has elapsed. The method may further comprise: dispensing an amount of a second liquid on the surface of the portion of the polishing body, wherein the amount of the second liquid is disposed adjacent to the amount of the first liquid; and exposing the applied amount of the second liquid to electromagnetic radiation generated from a source for a third period of time to only partially cure the amount of the second liquid, wherein the amount of the first liquid and the amount of the second liquid are simultaneously exposed to the electromagnetic radiation generated from the source.
Embodiments of the present disclosure may further provide a method of forming a polishing pad, the method comprising forming a plurality of layers on a surface, wherein forming the plurality of layers comprises depositing an amount of a first composition on one or more regions of the surface, depositing an amount of a second composition on one or more second regions of the surface, wherein the one or more first regions and the one or more second regions form a continuous portion of each of the plurality of layers; and exposing the one or more first areas and the one or more second areas to electromagnetic radiation generated from a source for a first period of time to partially cure only a portion of the applied amount of the first composition and the applied amount of the second composition.
Embodiments of the present disclosure may further provide a method of forming an abrasive article, the method comprising forming a plurality of urethane acrylate polymer layers, wherein forming the plurality of urethane acrylate polymer layers comprises mixing a first amount of a first multifunctional urethane acrylate oligomer, a first amount of a first mono-or multifunctional acrylate monomer, and a first amount of a first curing agent to form a first precursor formulation having a first viscosity that enables dispensing of the first precursor formulation using a build-up (additive) manufacturing process; mixing a second amount of the first multifunctional urethane acrylate oligomer, a second amount of the first mono-functional or multifunctional acrylate monomer, and a second amount of the first curing agent to form a second precursor formulation having a second viscosity that enables the second precursor formulation to be dispensed using a build-up manufacturing process; dispensing a first precursor formulation on a first region of a surface by using a build-up manufacturing process; dispensing a second precursor formulation on a second region of the surface by using a build-up manufacturing process; and exposing the dispensed first amount of the first precursor formulation and the dispensed first amount of the second precursor formulation to electromagnetic radiation for a first period of time to only partially cure the first amount of the first precursor formulation and the first amount of the second precursor formulation.
Embodiments of the present disclosure may further provide a method of forming an abrasive article, the method comprising forming a plurality of urethane acrylate polymer layers, wherein forming the plurality of urethane acrylate polymer layers comprises dispensing a plurality of droplets of a first precursor formulation in a first pattern on a surface of an abrasive body comprising a first material composition, wherein the first precursor formulation comprises a first multifunctional urethane acrylate oligomer, a first amount of a first multifunctional acrylate precursor, and a first amount of a first curing agent; dispensing a plurality of droplets of a second precursor formulation in a second pattern on the surface of the abrasive body, wherein the second precursor formulation comprises a first multifunctional urethane acrylate oligomer and/or a first multifunctional acrylate precursor; and exposing the dispensed droplets of the first precursor formulation and the dispensed droplets of the second precursor formulation to electromagnetic radiation for a first period of time, thereby only partially curing the droplets of the first precursor formulation and the droplets of the second precursor formulation.
Embodiments of the present disclosure may further provide a polishing pad having a polishing surface configured to polish a surface of a substrate, the polishing pad comprising a plurality of first polishing elements each comprising a plurality of first polymer layers comprising a first polymer material, wherein at least one of the plurality of first polymer layers forms the polishing surface; and a base region disposed between at least one of the plurality of first polishing elements and the support surface of the polishing pad. The substrate region can include a plurality of layers, each layer including a plurality of solidified drops of a first polymeric material and a plurality of solidified drops of a second polymeric material, and wherein a first E '30/E' 90 ratio of the first polymeric material is greater than 6. In some cases, the second E '30/E' 90 ratio of the second polymeric material can also be greater than 6, and the first E '30/E' 90 ratio is different than the second E '30/E' 90 ratio.
Embodiments of the present disclosure may further provide a polishing pad having a polishing surface configured to polish a surface of a substrate, the polishing pad comprising a plurality of first polishing elements each comprising a plurality of first polymer layers comprising a first polymer material, wherein at least one of the plurality of first polymer layers forms the polishing surface; and a base region disposed between at least one of the plurality of first polishing elements and the support surface of the polishing pad, wherein the base region comprises a plurality of layers each comprising a plurality of solidified droplets of a first polymer material and a plurality of solidified droplets of a second polymer material. The first polymeric material can have a first storage modulus and the second polymeric material can have a second storage modulus, wherein the first storage modulus is greater than the second storage modulus and the substrate region comprises a volume percentage of the second polymeric material that is greater than a volume percentage of the first polymeric material.
Drawings
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
Fig. 1A is a schematic sectional view of a polishing table.
Fig. 1B to 1E are schematic cross-sectional views of a part of the polishing head and polishing pad arrangement placed in the polishing table illustrated in fig. 1A.
Fig. 1F-1G are schematic cross-sectional views of a portion of a polishing head and polishing pad arrangement disposed in the polishing table illustrated in fig. 1A, according to an embodiment of the disclosure.
Fig. 1H is a schematic cross-sectional view of a portion of a substrate polished using the polishing table configuration illustrated in fig. 1B-1C.
Fig. 1I is a schematic cross-sectional view of a portion of a substrate being polished using the polishing table configuration illustrated in fig. 1D-1E.
Fig. 1J is a schematic cross-sectional view of a portion of a substrate polished using the polishing table configuration illustrated in fig. 1F-1G, in accordance with an embodiment of the present disclosure.
Fig. 2A is a schematic isometric and cross-sectional view of a polishing pad according to an embodiment of the present disclosure.
Fig. 2B is a schematic partial top view of a polishing pad according to an embodiment of the disclosure.
Fig. 2C is a schematic isometric and cross-sectional view of a polishing pad according to an embodiment of the present disclosure.
Fig. 2D is a schematic side cross-sectional view of a portion of a polishing pad according to an embodiment of the present disclosure.
Fig. 2E is a schematic side cross-sectional view of a portion of a polishing pad according to an embodiment of the disclosure.
Fig. 2F-2K are top views of polishing pad designs according to embodiments of the present disclosure.
Fig. 3A is a schematic view of a system for manufacturing an advanced polishing pad according to an embodiment of the present disclosure.
Fig. 3B is a schematic view of a portion of the system illustrated in fig. 3A, according to an embodiment of the present disclosure.
Fig. 3C is a schematic view of a dispensed droplet disposed on a surface of an area of the advanced polishing pad illustrated in fig. 3B, according to an embodiment of the present disclosure.
Fig. 4A-4D are top views of pixel maps for forming advanced polishing pads according to at least one embodiment of the present disclosure.
Fig. 4E is a schematic top view of a web-type or roll-to-roll type polishing pad according to an embodiment of the present disclosure.
Fig. 4F is a schematic side cross-sectional view of a portion of a polishing pad according to an embodiment of the present disclosure.
Fig. 5A illustrates tan versus temperature profiles for various materials and advanced polishing pads, in accordance with an embodiment of the disclosure.
Fig. 5B illustrates a stress versus strain graph for materials that may be used for advanced polishing pads, according to an embodiment of the present disclosure.
Figure 5C illustrates a storage modulus versus temperature profile for a pad material subjected to a cyclic treatment in a polishing system, in accordance with an embodiment of the disclosure.
Fig. 6 is a schematic side cross-sectional view of a portion of a polishing pad according to an embodiment of the present disclosure.
Fig. 7 is a schematic side cross-sectional view of a polishing pad with a transparent region formed thereon according to an embodiment of the present disclosure.
Fig. 8 is a schematic perspective cross-sectional view of a polishing pad including a supporting foam layer according to an embodiment of the present disclosure.
Fig. 9A illustrates tan versus temperature profiles for various materials and advanced polishing pads, in accordance with an embodiment of the disclosure.
Fig. 9B-9C are each schematic side cross-sectional views of portions of advanced polishing pads according to embodiments of the present disclosure.
To facilitate understanding, common usage words are used to indicate common elements in the drawings, where possible. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
Detailed Description
The present disclosure relates to advanced polishing pads with tunable chemical, material, and structural properties, and new methods of manufacturing the polishing pads. In accordance with one or more embodiments of the present disclosure, it has been discovered that polishing pads having improved characteristics can be produced by additive manufacturing processes, such as three-dimensional (3D) printing processes. Embodiments of the present disclosure provide an advanced polishing pad having discrete features and geometries formed from at least two different materials formed from precursors (e.g., "resin precursor compositions") including, but not limited to, functional polymers, functional oligomers, monomers, reactive diluents, flow additives, curing agents, photoinitiators, and curing synergists. The resin precursor composition material may include a functional polymer, a functional oligomer, a monomer, and a reactive diluent, which may be at least monofunctional and may undergo polymerization upon exposure to a free radical, Lewis acid (Lewis acid), and/or electromagnetic radiation. As one example, the advanced polishing pad can be formed from multiple polymeric layers by automated sequential deposition of at least one resin precursor composition followed by at least one curing step, wherein each layer can represent at least one polymer composition and/or regions of different composition. In some embodiments, the layers and/or regions of the advanced polishing pad can include a composite structure, such as a radiation-cured polymer containing at least one filler (such as metal, semi-metal oxide, carbide, nitride, and/or polymer particles). In some embodiments, fillers may be used to increase wear resistance, reduce friction, resist wear, improve cross-linking and/or thermal conductivity of the entire pad or certain areas of the pad. Thus, an advanced polishing pad comprising a pad body and discrete features created above, on, and within the pad body can be formed simultaneously from a variety of different materials and/or compositions of materials, thus enabling micron-scale control of pad configuration and properties.
In addition, a polishing pad is provided that includes desired pad polishing characteristics over the full range of polishing processes. Typical polishing pad characteristics include static and dynamic characteristics of the polishing pad, which are influenced by the composite properties of the individual materials within the polishing pad and the overall polishing pad structure. Advanced polishing pads can include regions containing a variety of discrete materials and/or regions containing a gradient in material composition in one or more directions within the formed polishing pad. Examples of some mechanical properties that can be adjusted to form an advanced polishing pad with desired polishing performance over the range of the polishing process include, but are not limited to, storage modulus E', loss modulus E ", hardness, yield strength, ultimate tensile strength, elongation, thermal conductivity, zeta potential, mass density, surface tension, pinto, fracture toughness, surface roughness (R)a) And other related characteristics. Examples of some dynamic characteristics that may be adjusted within an advanced polishing pad may include, but are not limited to, tan (tan), storage modulus ratio (or E '30/E' 90 ratio), and other relevant parameters, such as energy loss factor (KEL). The energy loss factor (KEL) relates to the elastic rebound and damping effects of the mat material. KEL may be defined by the following equation: KEL tan 1012/[E’*(1+(tan)2)]Wherein the unit of E' is Pascal (Pascal). KEL is typically measured using Dynamic Mechanical Analysis (DMA) at a temperature of 40 ℃ and a frequency of 1 hertz or 1.6 hertz (Hz). Unless otherwise specified, storage modulus E ', E ' 30/E '90 ratio and recovery measurements provided hereinWere performed using a DMA test method performed at a frequency of about 1 hertz (Hz) and a temperature change rate of about 5 deg.c/minute. By controlling one or more pad characteristics, an improved polishing process performance, improved polishing pad life, and improved polishing process repeatability can be achieved. Examples of pad configurations exhibiting one or more of these characteristics will be discussed further below in connection with one or more embodiments discussed herein.
As will be discussed in more detail below, the storage modulus E' is an important factor in ensuring that the polishing results are uniform across the substrate, and thus is a useful measure of polishing pad performance. The storage modulus E' is typically calculated by dividing the applied tensile stress on the elastic straight portion of the stress-strain curve by the tensile strain (e.g., slope or Δ y/Δ x). Similarly, the ratio of viscous stress to viscous strain is used to define the loss modulus E ". It should be noted that the storage modulus E' and the loss modulus E "are inherent material properties resulting from intermolecular and intramolecular chemical bonds within the material. The storage modulus can be measured at a desired temperature using a material testing technique such as Dynamic Mechanical Analysis (DMA) (e.g., astm D4065, D4440, and D5279). When comparing the properties of different materials, the storage modulus E' of the materials is typically measured at a single temperature, in a range between 25 ℃ and 40 ℃, such as 40 ℃.
Another relevant measure of polishing pad performance and uniformity is a measure of the damping capacity of the material, such as the compression and rebound damping characteristics of the polishing pad. A common method for measuring damping is to calculate the tan (tan) of the material at the desired temperature, where tan is the loss modulus/storage modulus E "/E'. When comparing properties of different materials, tan measurements of the materials are typically compared at a single temperature, such as 40 ℃. Unless otherwise specified, the tan measurements provided herein are performed using a DMA test method performed at a frequency of 1 hertz (Hz) and a temperature ramp rate of about 5 ℃/minute. tan is generally a measure of how "viscous" chemical structures in a material respond to the application of cyclic strain (e.g., bond rotation, polymer chain slippage and movement) compared to spring-like elastic chemical structures in a material, such as flexible and coiled aliphatic polymer chains that return to a preferred low energy configuration and structure when a force is released. For example, when cyclic loads are applied, the less elastic the material, the less viscous molecular segments of the material will respond (phase shift) behind the elastic molecular segments of the material and generate heat. The heat generated in the polishing pad during substrate processing can have an effect on the polishing process results (e.g., polishing uniformity) and, therefore, should be controlled and/or compensated for by judicious selection of the pad material.
The hardness of the material in the polishing pad contributes to the polishing uniformity results and material removal rates found on the substrate after polishing. The hardness of a material, also often measured using the rockwell, brinell, or shore hardness scale, measures the indentation resistance of the material and provides an empirical hardness value, and may track or increase with increasing storage modulus E'. Pad materials are typically measured using the shore hardness scale, which is typically measured using the ASTM D2240 technique. Typically, pad material hardness properties are measured on the shore a or shore D scale, which is typically used for softer or low storage modulus E' polymeric materials, such as polyolefins. Rockwell hardness (e.g., ASTM D785) testing may also be used to test the hardness of "hard" rigid engineering polymeric materials, such as thermoplastic and thermoset materials.
Polishing pad apparatus and polishing method
Figure 1A is a schematic cross-sectional view of a polishing table 100 that may be placed within a larger Chemical Mechanical Polishing (CMP) system containing multiple polishing tables 100. The grinding table 100 includes a platen 102. The platform 102 is rotatable about a central axis 104. The polishing pad 106 may be placed on the platen 102. Typically, the polishing pad 106 covers the upper surface of the platen 102, which is at least one to two times larger in size than the substrate 110 (e.g., substrate diameter) to be processed in the polishing table 100. In one example, the diameter of the polishing pad 106 and platen 102 is between about 6 inches (150mm) and about 40 inches (1,016 mm). The polishing pad 106 includes a polishing surface 112 configured to contact and process one or
The delivery arm 118 delivers an abrasive fluid 116, such as an abrasive slurry, supplied to the abrasive surface 112 during abrading. The polishing liquid 116 may contain abrasive particles, pH adjusters, and/or chemically active components to achieve chemical mechanical polishing of the substrate. The slurry chemistry of 116 is designed to polish wafer surfaces and/or features that may include metal, metal oxide, and semi-metal oxide. The polishing table 100 also typically includes a pad conditioning assembly 120 that includes a conditioning arm 122 and actuators 124 and 126 configured to cause a pad conditioning disk 128 (e.g., a diamond impregnated disk) to be pushed against and across the polishing surface 112 at different times during the polishing process cycle, thereby abrading and restoring the surface 112 of the polishing pad 106.
Fig. 1B-1C are schematic cross-sectional views of a portion of a polishing head 108 and a conventional "hard" or high storage modulus E' modulus polishing pad 106A disposed in a polishing table 100. Fig. 1D-1E are schematic cross-sectional views of a portion of a polishing head 108 and a conventional soft or low storage modulus E'
Figure 1B illustrates a portion of an edge of a
Fig. 1H is a schematic cross-sectional view of a portion of a
FIG. 1D illustrates a
FIG. 1I is a schematic cross-sectional view of a portion of a substrate polished using a conventional soft or low storage modulus E'
Advanced polishing pad
Embodiments of the present disclosure generally provide an
Fig. 1J is a schematic cross-sectional view of a portion of a substrate polished using an
In some embodiments, the
Materials having the desired low, medium and/or high storage modulus E 'properties at a temperature of 30 ℃ (E' 30) are summarized in table 1:
TABLE 1
Low modulus composition
Medium modulus composition
High modulus composition
E’30
5MPa-100MPa
100MPa-500MPa
500MPa-3000MPa
In one embodiment and referring to table 1, the
The term advanced polishing
Advanced polishing pads can be formed by automated sequential deposition of at least one resin precursor composition, followed by at least one curing step, layer-by-layer, wherein each layer can represent at least one polymer composition and/or regions of different composition. The composition may include a functional polymer, a functional oligomer, a reactive diluent, and a curing agent. The functional polymer may include a multifunctional acrylate precursor component. To form the plurality of solid polymeric layers, one or more curing steps may be used, such as exposing one or more of the compositions to UV radiation and/or thermal energy. In this way, the entire polishing pad can be formed from multiple polymeric layers by 3D printing. The thickness of the cured layer may be from about 0.1 microns to about 1 millimeter, such as from 5 microns to about 100 microns, and such as from 25 microns to about 30 microns.
Polishing pads according to the present disclosure may have different mechanical properties on the
Advanced polishing pad configuration examples
Fig. 2A is a schematic perspective cross-sectional view of an
In one embodiment, the
Fig. 2B is a schematic partial top view of an advanced polishing pad 200B according to an embodiment of the disclosure. The advanced polishing pad 200b is similar to the
Fig. 2C is a schematic perspective cross-sectional view of an advanced polishing pad 200C according to an embodiment of the disclosure. The polishing pad 200c includes a plurality of
The
In fig. 2C, the first abrasive element 204C is shown as a cylinder extending from the second abrasive element 206C. Alternatively, the first
Fig. 2D is a schematic partial side cross-sectional view of a polishing
In one embodiment, the boundary between the first polishing element 204d and the second polishing element 206d includes a cohesive transition from at least one material composition to another material composition, such as a transition or composition gradient from a first composition used to form the first polishing element 204d and a second composition used to form the second polishing element 206 d. The cohesiveness of a material is a direct result of the build-up manufacturing process described herein, which enables micron-scale control and intimate mixing of two or more chemical compositions in a layer-by-layer build-up formation structure.
Fig. 2E is a schematic partial cross-sectional view of a polishing pad according to an embodiment of the disclosure. The
Fig. 2F-2K are schematic plan views of various polishing pad designs according to embodiments of the present disclosure. Each of fig. 2F-2K includes a pixel map having white regions (regions in white pixels) respectively representing first polishing elements 204F-204K for contacting and polishing a substrate; and black areas (areas in black pixels) that represent the
Fig. 2F is a schematic pixel diagram of an advanced polishing pad design 200F with a plurality of concentric polishing features 204F. The
Fig. 2G is a schematic pixel diagram of a polishing pad design 200G having a plurality of segmented first polishing elements 204G arranged in concentric circles. In one embodiment, the segmented first
Fig. 2H is a schematic pixel diagram of a polishing pad design 200H with a spiral-shaped first polishing element 204H disposed over a second polishing element 206H. In fig. 2H, the polishing pad 200H has four spiral-shaped first polishing elements 204H extending from the center of the polishing pad to the edge of the polishing pad. Even though four spiral grinding features are shown, a fewer or greater number of spiral first grinding elements 204h may be arranged in a similar manner. The spiral first polishing element 204h defines a spiral groove 218 h. In one embodiment, each of the spiral-shaped first polishing elements 204h has a constant width. In one embodiment, spiral groove 218h also has a constant width. During polishing, the polishing pad may be rotated about the central axis in a direction opposite to the direction of the spiral-shaped first polishing elements 204h, thereby retaining the polishing slurry in the spiral-shaped grooves. For example, in fig. 2H, the spiral-shaped first polishing elements 204H and the spiral-shaped grooves are formed in a counterclockwise direction, and thus the polishing pad may be rotated clockwise during polishing, thereby retaining the polishing slurry in the spiral-shaped grooves and on the polishing pad. In some configurations, each spiral groove is continuous from the center of the polishing pad to the edge of the polishing pad. This continuous spiral groove allows the polishing slurry to flow from the center of the polishing pad to the edge of the polishing pad along with any polishing waste. In one embodiment, the polishing pad can be cleaned by rotating the polishing pad in the same direction as the spiral-shaped first polishing elements 204H (e.g., counterclockwise in fig. 2H).
Fig. 2I is a schematic pixel diagram of a polishing pad design 200I with segmented first polishing elements 204I arranged in a spiral pattern on second polishing elements 206I. The advanced polishing pad illustrated in fig. 2I is similar to the polishing pad in fig. 2H, except that the first polishing elements 204I are segmented and the radial pitch of the first polishing elements 204I is different. In one embodiment, the radial pitch of the segmented first polishing elements 204i decreases from the center of the polishing pad to the edge region of the polishing pad, thereby regulating and/or controlling the retention of slurry over different regions of the polishing pad surface during processing.
Fig. 2J is a schematic pixel diagram of a polishing pad design 200J with a plurality of discrete first polishing elements 204J formed in a second polishing element 206J. In one embodiment, each of the plurality of first polishing elements 204j may be a cylindrical structure, similar to the configuration illustrated in fig. 2C. In one embodiment, the plurality of first polishing elements 204j may have the same size in the plane of the polishing surface. In one embodiment, the plurality of cylindrical first polishing elements 204j may be arranged in concentric circles. In one embodiment, the plurality of cylindrical first polishing elements 204j may be arranged in a regular 2D pattern relative to the plane of the polishing surface.
Fig. 2K is a schematic pixel diagram of a polishing pad design 200K having a plurality of discrete first polishing elements 204K formed on a second polishing element 206K. The polishing pad of fig. 2K is similar to the polishing pad of fig. 2J, except that some of the first polishing elements 204K in fig. 2K may be connected to form one or more closed circles. The one or more closed loops may create one or more dams to retain the polishing slurry during polishing.
The
Additive manufacturing apparatus and process examples
Fig. 3A is a schematic cross-sectional view of an
The
The droplet ejection printer 306 may include one or more printheads 308 having one or more nozzles (e.g.,
The
After 3D printing, the
Additive manufacturing processes provide a convenient and highly controllable process for producing advanced polishing pads having discrete features formed from different materials and/or different material compositions. In one embodiment, the soft or low storage modulus E 'feature and/or the hard or high storage modulus E' feature may be formed using a build-up manufacturing process. For example, the soft or low storage modulus E 'feature of the polishing pad can be formed by a first composition comprising a polyurethane fragment dispensed from the
In another embodiment, the first
Fig. 3B is a schematic cross-sectional view of a portion of the
Fig. 3C is a close-up cross-sectional view of a dispense droplet 343 disposed on surface 346A of previously formed layer 346. Based on the characteristics of the material within dispense drop 343 and due to the surface energy of surface 346A, the dispense drop will spread across the surface by surface tension in an amount greater than the original dispense drop (e.g., drop "a" or "B") size. The amount of spread of the dispensed drops will vary with time from the time of deposition on surface 346A. However, after a very short period of time (e.g. <1 second), the spread of the drop will reach an equilibrium size and have an equilibrium contact angle α. The spread of the dispensed drops on the surface affects the resolution of the drops placed on the surface of the growing polishing pad and, therefore, the resolution of the features and material compositions present in the various regions of the final polishing pad.
In some embodiments, it is desirable to expose one or both of the drops "a" and "B" after a period of time in contact with the substrate surface so that each drop cures or "sets" on the substrate surface at a desired size before the drop has a chance to diffuse to its uncured equilibrium size. In this case, the energy supplied by the
It has been found that it is necessary to partially cure each dispensed drop to "fix" its surface characteristics and size during the printing process. The ability to "fix" the drops at a desired size may be achieved by adding a desired amount of at least one cure enhancing component to the drop material composition during the build-up manufacturing process and delivering a sufficient amount of electromagnetic energy from the curing device 320And (5) realizing. In some embodiments, it is desirable to use a material capable of being at about 1 millijoule per square centimeter (mJ/cm) during the build-up layer formation process2) And 100mJ/cm2Between (such as about 10-20 mJ/cm)2) Ultraviolet light (ultraviolet; UV) light is delivered to the
In some embodiments, the dispensing drops "a", "B" may be about 10 microns to about 200 microns in size, such as about 50 microns to about 70 microns. Depending on the surface energy (dynes) of the substrate or polymer layer over which the droplets are dispensed and the substrate or polymer layer, the uncured droplets may diffuse to a size 343A of between about 10 microns and about 500 microns (such as between about 50 microns and about 200 microns) on or across the surface. In one example, the height of such droplets may be from about 5 microns to about 100 microns, depending on factors such as surface energy, wetting, and/or resin precursor composition, which may include other additives such as flow agents, thickeners, and surfactants. One source of additives is BYK-Gardner GmbH, Gretsride, Germany.
In some embodiments, it is generally desirable to select the photoinitiator, the amount of photoinitiator in the droplet composition, and the amount of energy supplied by the
The resolution of pixels within a pixel map used to form a layer or a portion of a layer by an additive manufacturing process may be defined by the average "fixed" size of dispensed drops. The material composition of a layer or a portion of a layer may thus be defined by a "dispensed drop composition" which is a percentage of the total number of pixels in the layer or portion of the layer that include a drop of a certain drop composition. In one example, if a layer region forming an advanced polishing pad is defined as a dispense drop composition having 60% of a first dispense drop composition, then 60% of the pixels in that region will include fixed drops comprising the first material composition. In the case where a portion of a layer contains more than one material composition, it is also desirable to define the material composition of the regions within the advanced polishing pad as having a "material composition ratio". The material composition ratio is the ratio of the number of pixels having a first material composition disposed thereon to the number of pixels having a second material composition disposed thereon. In one example, if an area is defined to contain 1,000 pixels disposed on a surface area, and 600 pixels contain a fixed drop of a first drop composition and 400 pixels contain a fixed drop of a second drop composition, the material composition ratio would include a 3:2 ratio of the first drop composition to the second drop composition. In a configuration where each pixel may contain more than one fixed drop (e.g., 1.2 drops per pixel), then the material composition ratio will be defined by the ratio of the number of fixed drops of the first material to the number of fixed drops of the second material present within the defined area. In one example, if a region is defined to contain 1,000 pixels and there are 800 anchor drops of the first drop composition and 400 anchor drops of the second drop composition in the region, the material composition ratio in the region of the advanced polishing pad will be 2: 1.
The amount of cure of the surface of the dispensed drop that forms the next underlying layer is an important polishing pad formation process parameter, as this amount of cure in the "initial dose" affects the surface energy to which subsequent layers of the dispensed drop will be exposed during the build-up manufacturing process. The amount of initial curing dose is also important as it will also affect the amount of curing that each deposited layer will ultimately achieve in the formed polishing pad as each deposited layer is repeatedly exposed to additional transmissive curing radiation supplied through subsequent deposited layers as it is grown thereon. It is generally desirable to prevent overcuring of the formed layer as it will affect the material properties of the overcured material and/or the wettability of the surface of the cured layer to the subsequently deposited dispensing drops in a subsequent step. In one example, to achieve polymerization of a 10-30 micron thick layer of dispensed droplets, the droplets may be dispensed onto a surface by dispensing each droplet and then exposing the dispensed droplet to radiation exposure at a level of about 10mJ/cm after a period of about 0.1 to about 1 second has elapsed2And about 15mJ/cm2UV radiation in between. However, in some embodiments, the radiation level delivered during the initial cure dose may vary from layer to layer. For example, due to the different dispensed droplet compositions in the different layers, the exposure to UV radiation in each initial dose may be adjusted to provide a desired level of cure in the currently exposed layer as well as one or more underlying layers.
In some embodiments, it is desirable to control the amount of drop composition and energy delivered from the
wherein A isC=CAnd AC=OIs 910cm found by FT-IR spectroscopy-1C-peak value and 1700cm-1C ═ O peak at (C). During polymerization, the C ═ C bonds in the acrylate are converted to C — C bonds, while the C ═ O in the acrylate is not converted. Thus, the intensity of C ═ C to C ═ O indicates the acrylate conversion. A. theC=C/AC=OThe ratio refers to the relative ratio of C ═ C to C ═ O bonds within the cured droplet, and thus (a)C=C/AC=O)0Denotes A in the dropletC=CAnd AC=OIs first ratio of (A) toC=C/AC=O)xDenotes A on the surface of the substrate after the drop has solidifiedC=CAnd AC=OThe ratio of. In some embodiments, the amount of initial curing of the layer may be equal to or greater than about 70% of the dispensed droplet. In some configurations, it may be desirable to partially cure the material in the dispensed droplet during initial exposure of the dispensed droplet to a level of curing energy of about 70% to about 80%, so a target contact angle of the dispensed droplet may be obtained. It is believed that the uncured or partial acrylate material on the top surface copolymerizes with the subsequent drops and thus creates cohesion between the layers.
The process of partially curing the dispensed drops during the initial layer formation step may also be important to ensure that there is some chemical bonding/adhesion between subsequent deposited layers due to the presence of residual unbound groups (such as residual acrylic groups). Because the residual unbound groups are not polymerized, they can participate in the formation of chemical bonds with subsequently deposited layers. The formation of chemical bonds between layers may thus increase the mechanical strength of the resulting advanced polishing pad in the layer by layer growth direction (e.g., the Z-direction in fig. 3B) during the pad formation process. As noted above, the bonds between the layers may thus be formed by both physical and/or chemical forces.
The mixture of dispensed droplets or the positioning of the dispensed droplets can be adjusted on a layer-by-layer basis to form individual layers with tunable characteristics and polishing pads with desired pad characteristics, which are composite characteristics that form the layer characteristics. In one example, as shown in fig. 3B, the mixture of dispensing drops includes 50:50 ratios of dispensing drops 343 and 347 (or a 1:1 ratio of material compositions), where the dispensing drop 343 includes at least one material that is different from the material present in the dispensing drop 347. During the deposition process, the characteristics of the portions of the polishing body 202 (such as the
Although only two compositions for forming the first
The ability to form compositional gradients locally within, and on the advanced polishing pad and the ability to tune chemical content is enabled by the "ink-jettable" low viscosity composition or low viscosity "ink" used in the 3D printing technique to form drops "a" and/or "B" illustrated in fig. 3B. The low viscosity ink is a "pre-polymer" composition and is a "precursor" to the formed first and second
Referring to the
Figures 4A-4F provide an advanced polishing pad that includes a compositional gradient over one or more regions of the polishing body. In fig. 4A-4D, white pixel markings are intended to schematically illustrate where dispensed droplets of the first material are dispensed, while black pixel markings illustrate where no material is dispensed within one or more layers for forming the polishing pad. By using these techniques, a compositional gradient of solidified material or material formed from multiple solidified drops may be formed in the printed layer used to form at least part of the complete polishing pad. The customized composition of the printed layer within the polishing pad can be used to adjust and customize the overall mechanical properties of the polishing pad. The composition of the abrasive features can vary in any suitable pattern. Although the polishing pads described herein are illustrated as being formed of two materials, this configuration is not intended to limit the scope of the disclosure provided herein, as polishing pads comprising three or more materials are within the scope of the disclosure. It should be noted that the composition of the polishing features in any polishing pad design (such as the polishing pads in fig. 2A-2K) may differ in a similar manner as the polishing pads in fig. 4A-4F.
Fig. 4A and 4B are black and white bitmap images reflecting pixel maps of printed layers of portions of the advanced polishing pad including the
Fig. 4C and 4D are schematic pixel diagrams 400C, 400D of polishing pads with features. In some embodiments, fig. 4C is a pixel map 400C of a first portion of a polishing pad, and fig. 4D is a pixel map 400D of a second portion of the same polishing pad. The polishing pads according to fig. 4C, 4D are similar to the polishing pads of fig. 4A, 4B, except that the gradient of the material composition of the polishing body varies across the polishing pad from left to right.
Fig. 4E is a schematic view of a web-based polishing pad 400E formed using an additive manufacturing process to form the polishing
Fig. 4F is a schematic side cross-sectional view of an advanced polishing pad 400F formed using a build-up manufacturing process to form a
In one embodiment, the
In some embodiments of the polishing
In one embodiment, it is desirable to form a gradient of material composition within the material used to form the first and/or second polishing elements in a direction perpendicular to the polishing surface of the polishing pad. In one example, it is desirable to have a higher concentration material composition for forming the
Advanced polishing pad formation Process example
In some embodiments, the construction of the
The coordinates present in the pixel map are used to define the location where a particular drop of uncured polymer will be placed using, for example, a polymer jetting printhead. Each coordinate of the X and Y positions and given pad support Z stage position will be defined based on the pixel map. Each of the X, Y and Z positions will include a drip dispensing or a drip non-dispensing condition. The printheads may be mounted in an array in the X and/or Y directions to increase build rates or deposit additional types of material. In the example shown in fig. 4A-4D, black pixels indicate locations where the nozzles will not deposit material, and white pixels indicate locations where the nozzles will deposit material. By combining material or pixel maps, a polishing pad having any desired shape or structural configuration in each of the formed layers can be printed by positioning a discrete drop in proximity to another discrete drop.
Additive manufacturing devices such as 3D printers can be used to form advanced polishing pads by depositing thermoplastic polymers, depositing and curing photosensitive resin precursor compositions, and/or laser pulse type sintering and melt dispensing powder layers. In some embodiments, the advanced polishing pad formation process may include a polymer jet printing method of UV sensitive materials. In this configuration, drops of a precursor formulation (e.g., the first printable ink composition 359) are ejected from the nozzles of the drop-jet printer 306 and a resin precursor composition is deposited onto the build table. Since the material is deposited from the nozzle array, the material may be leveled by using a roller or other means to smoothly drop a flat film layer or remove excess material. Simultaneously and/or immediately after dispensing the droplets, a UV lamp or LED radiation source passes over the deposited layer, thereby curing or partially curing the dispensed droplets into a solid polymer network. This process builds layers on top of the layers with sufficient cohesion within and between the layers to ensure good mechanical properties of the final embodiment of the pad model.
To better control polymer stress during the build process, heat may be added during the formation of one or more layers. The delivery of heat allows the polymer network formed in each cured or partially cured layer to relax and thus reduce stress and remove the stress history in this film. The stress in the film may cause unwanted deformation of the polishing pad during or after the polishing pad formation process. Heating the partially formed polishing pad while it is in the build tray of the printer ensures that the final pad properties are fixed through a layer-by-layer process, andpredictable pad compositions and polishing results can be achieved. In addition to introducing heat into the polishing pad formation process, the area surrounding the growing polishing pad may be modified to reduce exposure of the uncured resin to oxygen. This may be done by using a vacuum or by flooding the build chamber with nitrogen (N)2) Or other inert gas. Reducing oxygen on the growth pad will reduce inhibition of free radical polymerization reactions and ensure more complete surface curing of the dispensed droplets.
Formulation and Material examples
As discussed above, the materials used to form portions of the
In one embodiment, two or more polishing elements, such as the first and
Two classes of free radical photoinitiators may be used in one or more embodiments of the present disclosure provided herein. The first class of photoinitiators, also referred to herein as bulk curing photoinitiators, are initiators that decompose upon exposure to UV radiation, generating free radicals that initiate polymerization. The first type of photoinitiator may aid both surface curing and complete or bulk curing of the dispensed droplets. The first type of photoinitiator may be selected from the group including, but not limited to, benzoin ethers, benzyl ketals, acetophenone, alkylphenones, and phosphine oxides. The second type of photoinitiator (also referred to herein as a surface-curing photoinitiator) is a photoinitiator that is activated by UV radiation and which forms free radicals by hydrogen abstraction from a second compound that becomes the actual initiating free radical. This second compound is often referred to as a co-initiator or polymerization synergist and may be an amine synergist. Amine synergists are used to reduce oxygen inhibition and therefore the second type of photoinitiator can contribute to rapid surface cure. The second type of photoinitiator may be selected from the group including, but not limited to, benzophenone compounds and thioxanthone compounds. The amine synergist may be an amine with active hydrogen, and in one embodiment, an amine synergist such as an amine-containing acrylate may be combined with the benzophenone photoinitiator in the resin precursor composition formulation so that in the curing process: a) limiting oxygen inhibition, b) rapidly curing the droplet or layer surface, thereby fixing the size of the droplet or layer surface, and c) increasing layer stability. In some cases, to prevent or prevent radical quenching by diatomic oxygen (which slows or inhibits the radical cure mechanism), we can select oxygen limited or oxygen free cure atmospheres or environments, such as inert gas atmospheres, and dry, degassed, and nearly oxygen free chemical reagents.
It has been found that controlling the amount of chemical initiators in the printing formulation is an important factor in controlling the characteristics of the formed advanced polishing pads, as repeated exposure of the underlying layers to curing energy in forming advanced polishing pads will affect the characteristics of these underlying layers. In other words, repeated exposure of the deposited layer to a certain amount of curing energy (e.g., UV light, heat, etc.) will affect the degree of curing within each formed layer or over-cure the surface of such layer. Thus, in some embodiments, it is desirable to ensure that the surface cure kinetics are not faster than full cure (bulk cure) because the surface will cure first and block additional UV light from reaching the material below the surface cure area; thus resulting in the entire partially cured structure being "not fully cured". In some embodiments, it is desirable to reduce the amount of photoinitiator to ensure proper chain extension and crosslinking. Generally, higher molecular weight polymers will be formed by slower controlled polymerization. It is believed that if the reaction product contains too many free radicals, the reaction kinetics may proceed too fast and the molecular weight will be lower, which in turn will reduce the mechanical properties of the cured material.
In some embodiments, the first and
A.
the difunctional oligomer (bisphenol-a ethoxylated diacrylate) represented by chemical structure a contains low, medium, and high storage modulus E' characteristics that may contribute to the materials present in the first and
B.
the polybutadiene diacrylate includes pendant allyl functionality (shown) that can undergo crosslinking reactions with other unsaturated unreacted sites. In some embodiments, residual double bonds in the polybutadiene block "m" react, thereby creating crosslinks that can contribute to reversible elastic properties. In one embodiment, the advanced polishing pad with compositional crosslinks may have a percent elongation of about 5% to about 40%, and an E '30 to E'90 ratio of about 6 to about 15. Some examples of crosslinking chemicals include sulfur vulcanization (sulfuration) and peroxides such as tributyl perbenzoate, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, and the like. In one embodiment, 3% of the total formulation weight of benzoyl peroxide reacts with the polybutadiene diacrylate to form crosslinks such that the crosslink density is at least about 2%.
Chemical structure C represents another type of reactive oligomer, urethane acrylate, a material that can impart flexibility and elongation to advanced polishing pads. The acrylate containing a polyurethane group may be an aliphatic or aromatic urethane acrylate, and the R or R' group shown in this structure may be aliphatic, aromatic, oligomeric, and may contain heteroatoms such as oxygen.
C.
The reactive oligomer may contain at least one reactive site, such as an acrylic site, and may be monofunctional, difunctional, trifunctional, tetrafunctional, pentafunctional, and/or hexafunctional, and thus serve as a focal point for crosslinking. Fig. 5B is a stress versus strain graph of some cured reactive oligomers that may be helpful in producing 3D printable ink compositions. The oligomer may represent a "soft" or low storage modulus E ' material, a "medium soft" or medium storage modulus E ' material, or a "hard" or high storage modulus E ' material (e.g., table 1). As shown, the storage modulus E' (e.g., tilt or Δ y/Δ x) increases from soft and flexible and stretchable urethane acrylates to acrylates, then to polyester acrylates, and then to the hardest in the series (hard and high storage modulus E "epoxyacrylates). Fig. 5B illustrates how we can select a storage modulus E 'material, or a range or mixture of storage modulus E' materials, that can be helpful in producing advanced polishing pads. Functional oligomers are available from a variety of sources, including Sartomer, Exxon, Pa., Dymax, Tolington, Connecticut, USA, and Allnex, Allerita, Ga.).
In embodiments of the present disclosure, multifunctional acrylates (including difunctional acrylates, trifunctional acrylates, tetrafunctional acrylates, and higher functional acrylates) may be used to create cross-linking within and/or between the materials used to form the first and second
D.E.
the type or crosslinker, chemical structure, or mechanism of forming the crosslinks is not limited to embodiments of the disclosure. For example, amine-containing oligomers can undergo a Michael addition reaction with acrylic moieties to form covalent crosslinks, or amine groups can react with epoxy groups to form covalent crosslinks. In other embodiments, the crosslinks may be formed by ionic or hydrogen bonding. The crosslinking agent may contain linear, branched, or cyclic molecular fragments, and may further contain oligomeric and/or polymeric fragments, and may contain heteroatoms such as nitrogen and oxygen. Cross-linking chemical compounds that can aid in polishing pad compositions are available from a variety of sources, including: Sigma-Aldrich, St.Louis, Mo, U.S., Sartomer, Exxon, Pa, Dymax, Tolington, Conn., and Allnex, Algorita, Ga.
As mentioned herein, the reactive diluent may be used as a viscosity reducing solvent mixed with the high viscosity functional oligomer to achieve a proper viscosity formulation, and then the diluent is copolymerized with the higher viscosity functional oligomer upon exposure to curing energy. In one embodiment, when n is about 4, the bisphenol a ethoxylated diacrylate may have a viscosity of about 1350 centipoise (cP) at 25 ℃, which may be too high to enable dispensing of such materials in a 3D printing process. Thus, it may be desirable to mix bisphenol a ethoxylated diacrylate with a lower viscosity reactive diluent such as a low molecular weight acrylate to reduce the viscosity to about 1cP to about 100cP at 25 ℃, such as about 1cP to about 20cP at 25 ℃. The amount of reactive diluent used depends on the formulation components and the viscosity of the diluent itself. For example, a reactive oligomer of 1000cP may require at least 40% dilution by weight of the formulation to achieve the target viscosity. Examples of reactive diluents are shown in chemical structures F (isobornyl acrylate), G (decyl acrylate), and H (glycidyl methacrylate):
F.
G.H.the corresponding viscosities of F-G at 25 ℃ are 9.5cP, 2.5cP, and 2.7cP, respectively. The reactive diluent may also be multifunctional and thus may undergo a crosslinking reaction or other chemical reaction that produces a polymeric network. In one embodiment, glycidyl methacrylate (H) acts as a reactive diluent and is mixed with the difunctional aliphatic urethane acrylate so the viscosity of the mixture is about 15 cP. The approximate dilution factor can be about 2:1 to about 10:1, such as about 5: 1. Amine acrylate may be added to this mixture, such as dimethylaminoethyl methacrylate, so it is about 10% by weight of the formulation. Heating the mixture from about 25 ℃ to about 75 ℃ results in the reaction of the amine with the epoxide and the formation of an adduct of the acrylated amine and the acrylated epoxide. Suitable free radical photoinitiators (such as651) It may then be added at 2% by weight of the formulation, and the mixture may be dispensed by a suitable 3D printer, thus a 20 micron thick layer is formed on the substrate. Subsequently, a strength of about 10mJ/cm was used2To about 50mJ/cm2By exposing the drop or layer to UV light at about 200nm to about 400nm for about 0.1 μ s to about 10 seconds(s), such as about 15 seconds, to cure the layer, thereby producing a thin polymer film. Reactive thinning that can facilitate 3D printing polishing pad compositionsThe diluent chemical compounds are available from a variety of sources including Sigma-Aldrich, St.Louis, Mo, Sartomer, Exxon, Pa, Dymax, Tolington, Connecticut, and Allnex, Allelex, Ga.
Another radiation curing method that may be helpful in producing polishing pads is cationic curing initiated by UV or low energy electron beams. The epoxy-containing material can be cationically curable, in which ring-opening polymerization of the epoxy groups can be initiated by cations such as protons and lewis acids. The epoxy-based material may be monomeric, oligomeric or polymeric and may have an aliphatic, aromatic, cycloaliphatic, araliphatic or heterocyclic structure; and it may also comprise epoxy groups as side groups or groups forming cycloaliphatic or heterocyclic systems.
UV-initiated cationic photopolymerization exhibits several advantages over free radical photopolymerization, including lower shrinkage, better transparency, better through cure via living polymerization, and oxygen-free inhibition. UV cationic polymerization can polymerize an important class of monomers that cannot be polymerized by free radical methods, such as epoxides, vinyl ethers, propenyl ethers, siloxanes, oxetanes, cyclic acetals and formals, episulfides, lactones, and lactams. These cationically polymerizable monomers include unsaturated monomers such as glycidyl methacrylate (chemical structure H) that can also undergo free radical polymerization via a carbon-carbon double bond as described herein. Photoinitiators that generate photoacid upon irradiation with UV light (about 225nm to 300nm) or electron beams include, but are not limited to, arylonium salts, such as iodonium and sulfonium salts, such as triarylsulfonium hexafluorophosphate, available from BASF (R) of Lodvieschig, GermanyProduct).
In one embodiment, the materials used to form the first and
In one embodiment, the 3D printed polymer layer may contain inorganic and/or organic particles for enhancing one or more pad properties of selected material layers present in forming the
Advanced polishing pad characteristics
An advantage of forming an
The materials in the
As discussed above, materials having different mechanical properties for use in the
For purposes of this disclosure and not intended to limit the scope of the disclosure provided herein, materials having the desired low, medium, and/or high storage modulus E ' properties (E ' 30) and (E ' 90) at 30 ℃ and 90 ℃ for the first and
TABLE 2
Low storage modulus compositions
Medium storage modulus composition
High storage modulus composition
E’30
5MPa-100MPa
100MPa-500MPa
500MPa-3000MPa
E’90
<17MPa
<83MPa
<500MPa
In one embodiment of the
In some embodiments, the storage modulus of the
To ensure that the polished surface of the polishing pad can be restored by using a pad conditioning process, it is also desirable that the material used to form
It is also desirable to provide a polishing pad with desirable damping characteristics to reduce the elastic rebound of the pad during polishing, which can cause dishing and other negative attributes associated with ring-like deformation of the pad during processing. Thus, to compensate for the need for the high storage modulus E 'material to contact the substrate surface during polishing, the
In one example, the
Another parameter that can be controlled in advanced polishing pads to further control process repeatability is the "recovery" of the pad material. FIG. 5C illustrates a plot of storage modulus E' as a function of temperature, which is obtained from a number of simulated polishing cycles of a material that may form part of the
It is also believed that in order to maintain optimal polishing uniformity and polishing performance on the substrate, the E '30: E'90 of the pad material should be controlled and adjusted as needed. To this end, in one embodiment, one or more of the formed pad materials (e.g., the material used to form the first polishing elements 204) and/or the E '30: E'90 ratio of the overall
In some embodiments, it is desirable to control the thermal conductivity of various sections of the advanced polishing pad to allow control of one or more polishing processes. In one embodiment, it is desirable to increase the thermal conductivity of the entire advanced polishing pad in the direction of the polishing surface (such as the Z-direction in fig. 1A-2K). In this example, the increased thermal conductivity in the Z-direction relative to conventional polishing pad formulations allows the polishing pad surface temperature to be maintained at a lower temperature, as it can be easier to conduct heat generated on the polishing pad surface during processing to a large thermal mass and/or to a frequently cooled polishing platen on which an advanced polishing pad is placed. The reduced polishing process temperature will reduce the polishing process variability often seen when polishing the first substrate of a batch of substrates and the last substrate of the batch (e.g., the 25 th substrate), and reduce the degradation of material properties (e.g., storage modulus E ', E' ratio, etc.) often present in the polymeric material in the batch of substrates. Alternatively, in some embodiments, it may be desirable to reduce the thermal conductivity of the entire advanced polishing pad in a direction perpendicular to the polishing surface (such as the Z-direction in fig. 1A). In this case, the reduced thermal conductivity in the Z-direction over conventional polishing pad formulations allows the polishing pad surface temperature to rise rapidly to the equilibrium processing temperature during polishing, as the polishing pad has a reduced ability to conduct heat generated on the polishing pad surface during processing to the polishing platen on which the advanced polishing pad is placed. Often higher but more stable polishing process temperatures may also be used to reduce polishing process variability often seen when polishing the first substrate of a batch of substrates and the last substrate of the batch (e.g., the 25 th substrate).
Accordingly, in some embodiments, one or more fillers, particles, or other materials need to be added to the
In one embodiment, the weight percentage of the silica particles in the surface layer may be about 0.1% to about 30% by weight of the formulation, such as 10% by weight, and it may increase the shore hardness and modulus of such coatings by about 10% to about 50%. In one embodiment, the particle surface may be chemically modified so the particles may be well mixed and/or suspended in the 3D polishing pad ink and thus more easily dispensed without phase separation. Chemical modification includes chemical binding of surfactant-like molecules to the polar surface of the particles by a "coupling agent", such as a silane coupling agent. Other coupling agents that may be useful include titanates and zirconates. Chemical binding, coupling or attachment of the coupling agent to the particle may occur through chemical reactions such as hydrolysis and condensation. The coupling agents and related chemical compounds described herein are available from a number of sources, including Gelest, moresville, pa, and Sigma-Aldrich chemical, st, mo.
In one embodiment, the
Advanced polishing pad formulation examples
As noted above, in some embodiments, the one or more materials used to form at least one of the two or more abrasive elements (such as the first
TABLE 3
Examples of functional oligomers can be found in table 3 under the entry O1-O5. Examples of functional reactive diluents and other additives can be found in table 3 under items M1-M6. Examples of curing components are found in Table 3 under items P1-P2. Items O1-O3, M1-M3, and M5-M6, found in Table 3, were obtained from Sartomer, USA, item O4 was obtained from Miwon Specialty Chemicals, Korea, item O5 was obtained from Allnex, Allita, Georgia, item M4 was obtained from BYK-Gardner GmbH, Germany, and items P1-P2 and A1 were obtained from Chiba Specialty Chemicals and RAHN USA.
One advantage of the additive layer fabrication process described herein includes the ability to form advanced polishing pads having properties that can be tailored based on the material composition and structural configuration of the various materials used within the pad body structure. The following information provides some examples of some material formulations and the effect of varying various components in these formulations and/or processing techniques on some of the characteristics required to form an advanced polishing pad that will achieve improved polishing results over conventional polishing pad designs. The information provided in these examples may be used to form at least a portion of the
The examples of cured resin precursor composition components described above and below are intended as comparative examples, and one skilled in the art can find other suitable monomers/oligomers from a variety of sources to achieve the desired properties. Some examples of reactive diluents are 2-ethylhexyl acrylate, octyldecyl acrylate, cyclic trimethylolpropane formal acrylate, caprolactone acrylate, and alkoxylated dodecyl methacrylate. The first material was purchased from Sigma-Aldrich, and the remainder were available from Sartomer in the United states and/or Rahn AG in the United states (
Example 1 storage moduli E ' and E '30: E '90 vs. control example
The selection, formulation, and/or formation of materials having the desired storage modulus E ' and E '30: E '90 ratio in the desired regions of the advanced polishing pad by using additive manufacturing processes is an important factor in ensuring that the polishing results achieved by the advanced polishing pad are uniform across the substrate. It should be noted that the storage modulus E' is an inherent material property of the formed material that results from chemical bonding within the cured polymeric material. The storage modulus can be measured at desired temperatures, such as 30 ℃ and 90 ℃, using Dynamic Mechanical Analysis (DMA) techniques. An example of a formulation containing different storage moduli is illustrated in table 4 below.
TABLE 4
Referring to
Example 2 storage modulus E' and recovery control example
Examples of different formulations that can be used to adjust the storage modulus E' and recovery (%) of materials used in advanced polishing pads are illustrated in table 5 below.
TABLE 5
Referring to
In some embodiments, it is desirable to adjust the various components in the droplet formulation used to form the low storage modulus E' material such that the amount of the component having a glass transition temperature (Tg) of less than or equal to 40 ℃ is greater than the amount of the component having a glass transition temperature (Tg) of greater than 40 ℃. Similarly, in some embodiments, it is desirable to adjust the various components in the droplet formulation used to form the high storage modulus E' material such that the amount of the component having a glass transition temperature (Tg) greater than 40 ℃ is greater than the amount of the component having a glass transition temperature (Tg) less than or equal to about 40 ℃.
EXAMPLE 3 contact Angle control example
Examples of different formulations deposited on a surface that can be used to adjust the contact angle of a drop are illustrated in table 6 below, as discussed above in connection with fig. 3C. As indicated above, it has been found that by controlling at least the following: 1) the composition of the components in the dispensed drop during the additive layer manufacturing process, 2) the amount of curing of the previously formed layer, 3) the amount of energy from the curing device, 4) the composition on the surface on which the dispensed drop is disposed, and 5) the amount of curing agent (e.g., photoinitiator) in the drop composition, the contact angle a of the dispensed drop can be controlled to improve the resolution of controlling the features formed by the additive layer manufacturing process described herein.
TABLE 6
Referring to
The contact angle of the drop formulation can be improved by: 1) full or bulk curing photoinitiators (e.g., first type photoinitiators) to ensure that mechanical properties of at least partially cured droplets can be achieved, 2) use of a second type of photoinitiator, such as benzophenone, and an amine synergist by attenuating O2The ability to quench free radicals generated via UV exposure (e.g., a second type of photoinitiator) in the environment for rapid surface curing and 3) surface modifiers that tend to make the surface of the dispensed droplet more or less polar. Surface modifiers may be used, for example, to alter the surface energy of the dispensed droplets when hydrophilic uncured resin droplets are deposited on a hydrophobic surface. This will result in a larger contact angle and thus ensure that the droplet does not "wet" the surface. Preventing surface wetting will allow for vertical accumulation (e.g., Z-direction) of subsequently deposited droplets. When the droplets are positioned horizontally next to each other one by one, it is desirable to prevent horizontal wetting of the surface, so the sidewalls of the vertically formed features will form vertically rather than a sloped shape. This contact angle improvement ensures that the sidewalls of the printed features are vertical or have a gentle slope when deposited one on top of the other. This resolution is important in advanced polishing pads because the substrate contact area of the polishing features needs to be maintained at a consistent contact area throughout each polishing process and/or because the pad polishing material needs to be removed by polishing or pad conditioning throughout the life of the pad.
Example 4-Low storage modulus E' tuning example
When combined with a higher storage modulus E ', the selection, formulation, and/or formation of materials having the desired low storage modulus E' and the desired E '30: E'90 ratio in various regions of the advanced polishing pad can be important factors in ensuring that the static and dynamic-related mechanical properties of the advanced polishing pad can be adjusted to achieve the desired polishing results. Examples of formulations containing different storage moduli E' are illustrated in table 7 below.
TABLE 7
Referring to
Example 5 advanced polishing pad characterization example
As discussed above, the additive manufacturing processes described herein have a particular placement of material compositions of desired characteristics within a particular pad region of an advanced polishing pad, so the characteristics of the deposited compositions can be combined to produce a polishing pad having "composite characteristics" of the average characteristics or characteristics of the individual materials. In one example, an advanced polishing pad can be formed so that it has a desired average loss tangent (tan) characteristic over a desired temperature range. Curves 921-923, 931-933 and 941 in FIG. 9A illustrate the average tan behavior of different configurations and/or loaded advanced polishing pads as a function of temperature.
Fig. 9B and 9C are side cross-sectional views of two basic configurations of an advanced polishing pad used to generate the tan and temperature data shown in fig. 9A. The tan versus temperature data seen in
Figure 9B illustrates a portion of an
Referring again to fig. 9A, the plotted data contains independent and discrete tan peaks for the first polishing pad material 901 and the second polishing pad material 902, as shown by
Fig. 9C illustrates a portion of an
The tan and temperature data seen in fig. 9A shows that the structure pitch or thickness of the layer in relation to the loading direction (e.g., curves 921 and 941) can have a great impact on the tan average properties within an advanced polishing pad. Referring to
Alternative pad structure design
Fig. 6 is a schematic perspective cross-sectional view of a
Fig. 7 is a schematic perspective cross-sectional view of a
The one or
In one embodiment, the
Fig. 8 is a schematic perspective cross-sectional view of a polishing pad 800 including a backing layer 806. The polishing pad 800 includes a second polishing element 804 and a plurality of first polishing elements 802 protruding from the second polishing element 804. The polishing pad 800 may be similar to any of the
In one embodiment, the material of the
Although the polishing pad shapes described herein are circular, abrasive particles according to the present disclosure can include any suitable shape, such as an abrasive web configured to move linearly during polishing.
The advanced polishing pads disclosed herein have several manufacturing and cost related advantages over conventional polishing pads. For example, conventional polishing pads generally include a machined and textured polishing surface supported by a subpad formed of a soft or low storage modulus E 'material, such as foam, to achieve a target hardness and/or storage modulus E' for the polishing substrate. However, by selecting materials with various mechanical properties and adjusting the size and arrangement of the different features formed on the advanced polishing pad, the same properties can be achieved in the pad body of the advanced polishing pad without the need for a subpad. Thus, advanced polishing pads reduce the cost of ownership for the user by eliminating the need for a subpad.
The increased complexity of polishing pad designs that will be required to polish next generation IC devices greatly increases the manufacturing complexity of these polishing pads. There are non-additive manufacturing type processes and/or subtractive processes that can be used to manufacture some aspects of these complex pad designs. These processes may include multi-material injection molding and/or sequential step UV casting to form a material layer from a single discrete material. These formation steps are then typically followed by machining and post-processing using grinding, milling or laser ablation operations or other subtractive techniques.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
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