阅读说明：本技术 化学机械抛光设备和方法 (Chemical mechanical polishing apparatus and method ) 是由 T·H·奥斯特赫尔德 R·巴贾杰 于 2015-07-23 设计创作，主要内容包括：本发明的实施例提供非均匀基板抛光设备,所述基板抛光设备包括具有两个或更多个区的抛光垫,每一个区经适配以将不同的浆料化学品施加至基板上的不同区以在基板上产生具有至少两个不同膜厚度的膜厚度分布。还提供经适配以抛光基板的抛光方法和系统,如同众多其他方面。(Embodiments of the present invention provide a non-uniform substrate polishing apparatus comprising a polishing pad having two or more zones, each zone adapted to apply a different slurry chemistry to a different zone on a substrate to produce a film thickness distribution on the substrate having at least two different film thicknesses. Polishing methods and systems adapted to polish substrates are also provided, as are numerous other aspects.)

1. A non-uniform substrate polishing apparatus, the substrate polishing apparatus comprising:

a polishing pad having two or more zones, each zone adapted to apply a different slurry chemistry to a different region on a substrate to produce a film thickness profile on the substrate having at least two different film thicknesses.

2. A substrate polishing system, comprising:

a controller comprising a processor and a memory, the memory adapted to store instructions adapted to operate the substrate polishing system;

a substrate holder adapted to hold a substrate; and

a polishing pad having two or more zones, each zone adapted to apply a different slurry chemistry to a different region on the substrate, thereby producing a film thickness profile on the substrate having at least two different film thicknesses;

wherein the substrate holder is adapted to rotate the substrate against the polishing pad under the direction of the controller.

3. A method of polishing a substrate, the method comprising:

rotating the substrate in the substrate holder against the moving polishing pad;

separately applying different slurry chemistries having different functionalities to at least two different zones of the polishing pad; and

removing different amounts of material from different regions of the substrate corresponding to the at least two different zones of the polishing pad.

4. The method of claim 3, wherein applying different slurry chemistries includes: different slurry chemistries with different material removal rates are applied.

5. The method of claim 3, wherein applying different slurry chemistries includes: different slurry components are applied, each having a different function than the other slurry components.

6. The method of claim 3, wherein applying different slurry chemistries includes: the different slurry chemistries are applied simultaneously.

7. The method of claim 3, wherein removing different amounts of material from different regions of the substrate comprises: a film thickness profile is generated on the substrate having at least two different film thicknesses.

Technical Field

The present invention relates generally to electronic device manufacturing and, more particularly, to methods and apparatus adapted to polish a surface of a substrate.

Background

In semiconductor substrate manufacturing, a Chemical Mechanical Polishing (CMP) process may be used to remove various layers (such as silicon, oxides, copper, etc.). Such polishing (e.g., planarization) can be achieved by: while the slurry is uniformly applied before the substrate (e.g., patterned wafer), the rotating substrate held in a holder (e.g., polishing head or carrier) is pressed against a rotating polishing pad. The slurry typically includes a mixture of an oxidizing agent, metal oxide abrasive particles, an etchant, a complexing agent, and a corrosion inhibitor. Thus, during polishing, a continuous process of oxidation by oxide and material removal by abrasive particles and etchant is performed by the slurry and polishing process. During this polishing process, precise control over the amount of material removed from the substrate is sought. However, in view of the limitations of the existing processes, it is difficult to achieve precise control, especially for removal of small layer thicknesses. Accordingly, what is needed are improved polishing apparatus, systems, and methods.

Disclosure of Invention

In some embodiments, a non-uniform substrate polishing apparatus is provided. The substrate polishing apparatus includes a polishing pad having two or more zones (zones), each zone adapted to apply a different slurry chemistry to a different region on a substrate to produce a film thickness profile on the substrate having at least two different film thicknesses.

In some other embodiments, a substrate polishing system is provided. The system comprises: a substrate holder adapted to hold a substrate; a polishing pad having two or more zones, each zone adapted to apply a different slurry chemistry to a different zone on a substrate to produce a film thickness profile on the substrate having at least two different film thicknesses.

In other embodiments, a method of polishing a substrate is provided. The method comprises the following steps: rotating the substrate in the substrate holder against the moving polishing pad; separately applying different slurry chemistries having different functionalities to at least two different zones of the polishing pad; and removing different amounts of material from different regions of the substrate corresponding to the at least two different zones of the polishing pad.

In other embodiments, a substrate polishing system is provided. The system comprises: a substrate holder adapted to hold a substrate; a polishing platform having a polishing pad movable relative to the substrate; and a dispensing system adapted to dispense at least two different slurry chemistries selected from the group consisting of: the material preserves slurry chemicals, slow material removal slurry chemicals, and aggressive material removal chemicals.

In other embodiments, a system for polishing a substrate is provided. The system comprises: a processor; a memory coupled to the processor and storing instructions executable on the processor, the instructions adapted to cause the system to: rotating the substrate in the substrate holder against the moving polishing pad; separately applying different slurry chemistries having different functionalities to at least two different zones of the polishing pad; and removing different amounts of material from different regions of the substrate corresponding to the at least two different regions of the polishing pad.

Other features and aspects of the present invention will become more fully apparent from the following detailed description of the exemplary embodiments, the appended claims and the accompanying drawings.

Drawings

Fig. 1A shows a schematic top view of a linear substrate polishing apparatus according to an embodiment.

FIG. 1B shows a schematic cross-sectional side view of a linear polishing apparatus of an embodiment taken according to section line 1B-1B of FIG. 1A.

FIG. 1C shows a schematic cross-sectional side view of a linear polishing apparatus of an embodiment taken according to section line 1C-1C of FIG. 1A.

Fig. 2A shows a schematic top view of a rotary substrate polishing apparatus according to an embodiment.

Fig. 2B shows a schematic side view of a rotary substrate polishing apparatus according to an embodiment.

Fig. 3A illustrates a top view of a slurry distributor according to an embodiment.

Fig. 3B shows a side view of a slurry distributor according to an embodiment.

Fig. 3C shows a first end view of a slurry distributor according to an embodiment.

Fig. 3D illustrates a second end view of the slurry distributor according to an embodiment.

Fig. 3E-3G illustrate various cross-sectional views of a slurry distributor according to embodiments.

Fig. 4 depicts a flow diagram of a method of polishing a substrate according to an embodiment.

Fig. 5 depicts a flow diagram of a method of polishing a substrate according to an embodiment.

Fig. 6 depicts a graph of stages (e.g., pulses) of a method of polishing a substrate according to an embodiment.

FIG. 7 depicts a graph of stages (e.g., pulses) of another method of polishing a substrate, according to an embodiment.

Fig. 8 and 9 are diagrams depicting portions of example film thickness profiles on a substrate before and after a non-uniform polishing method according to an embodiment has been applied.

Fig. 10 is a top view of a substrate polished to have a non-uniform thickness profile, in accordance with an embodiment.

Fig. 11 shows a schematic top view of a linear non-uniform substrate polishing apparatus according to an embodiment.

FIG. 12 is a schematic top view of a wedge-shaped polishing pad positioned on a substrate according to an embodiment.

FIG. 13 depicts a flow diagram of an example method of non-uniformly polishing a substrate, according to an embodiment.

Detailed Description

Embodiments described herein relate to apparatuses, systems, and methods useful for and suitable for polishing a surface of a substrate in semiconductor device manufacturing.

Previous systems have utilized slurries that include a mixture of slurry components. The composition of the slurry is adapted to effect various processes on the substrate, such as oxidation of the substrate surface by oxides and removal of material by abrasive particles and etchants. In a typical small removal process adapted to remove less than about 250 angstroms, the across-wafer removal variation can be as high as 50% -100% of the film thickness being removed. With advancing technology, increasingly thin films are being applied and can withstand polishing. For example, the films used in the formation of front-end structures (such as damascene metal gates, etc.) are very thin. When providing these films in device structures, it is desirable to remove these thin films with a relatively high degree of uniformity and control. Accordingly, as films become thinner, less material removal is achieved by CMP, and more precision is desired in the removal process. In the extreme case of Atomic Layer Deposition (ALD), where film thickness is measured in atomic layers (e.g., angstroms), material removal accuracy on the order of atomic layers is also desirable.

Therefore, there is a need for polishing apparatus and methods that allow for the removal of thin films, where such removal is achieved with very high uniformity. Furthermore, it is desirable that the method provide precise control over the removal process (i.e., the relative amount of removal). In some embodiments of the invention, the slurry components are physically separated. This can be used to provide more precise control over the amount of material removed. By physically (e.g., spatially) separating the slurry components, the polishing process can be provided with a significant interruption (e.g., formed as a solid zone of slurry components having different chemical compositions) between two or more of the slurry components (e.g., to achieve oxidation, material removal, and corrosion inhibition).

For example, in some embodiments, a polishing platform (e.g., comprising a pad support and a pad) can be separated to have two or more zones, wherein each zone is adapted to contain a different slurry composition. Each slurry component may have a different chemical composition. During polishing, the substrate may be moved or raster scanned (raster) across multiple zones, with each adjacent zone including a different slurry composition. Sequentially operating one cycle trans-regionally can be used to effectively remove, for example, one atomic layer. The total material removal can be precisely controlled by managing the number of cycles. Removal can be controlled at the atomic level.

In some embodiments, the polishing surface is separated (e.g., divided) into a plurality of zones, wherein each zone contains a separate slurry component that performs one of the oxidation, material removal, or corrosion inhibition processes. By raster scanning (e.g., scanning) across these isolated regions, a high cycle count can be achieved within a reasonable total polishing time. For example, in an oxidation zone containing an oxidizing slurry component, the oxidizing agent acts to oxidize a surface layer of the substrate. This oxidation process may be self-limiting, as only the surface layer is exposed to the oxidizing agent. In the material removal zone containing, for example, the removal and etchant slurry components, the abrasive and etchant attack the previously oxidized surface layer. The material removal region may be adjacent to the oxidation region. This material removal process may also be self-limiting, in that only the oxidized layer is removed. A corrosion-inhibiting zone containing a corrosion-inhibiting slurry component (e.g., including a corrosion inhibitor) acts on the previously abraded surface layer to limit corrosion of the abraded surface layer. The corrosion-inhibiting region may be provided adjacent to the oxidation region.

On the other hand, the application of the slurry components is separated in time, rather than physically. Thus, in one aspect, embodiments of the invention disclose a polishing process (e.g., a film removal process) that utilizes a multi-step reaction to affect uniform film removal. In particular, embodiments of the present invention temporally separate slurry components by introducing them separately and in a timed sequence. This can be used to provide more precise control over the amount of material removed. This multi-step polishing process is applicable to any application where CMP involves competing reactions.

Thus, in this regard, the polishing process will have a significant break (e.g., separation in time) between the management of the various slurry components used to implement the oxidation, material removal, and/or corrosion inhibition processes. In one or more embodiments, the oxidizing slurry component may be introduced first in time, followed by the material removal slurry component (e.g., comprising an abrasive and/or an etchant). This may be followed sequentially in some embodiments by the introduction of the corrosion inhibitor slurry components. In some embodiments, the sequence may be followed by the introduction of a rinsing liquid (e.g., Deionized (DI) water). In other embodiments, the slurry components may be introduced between each slurry introduction stage. These slurry components may be managed between the substrate and the polishing pad during the polishing process, as will be explained further herein.

Furthermore, in some embodiments, non-uniform removal or even localized removal of material may be achieved using non-uniform concentrations and/or application of slurry chemicals. In other words, other embodiments of the present invention may be used to selectively remove only a partial region of the film on the surface of the substrate, unlike the above-described embodiments. For example, a desired number of material layers outside a predetermined radius from the center of the substrate may be removed, while the same material layers within the radius may remain on the substrate. Accordingly, embodiments of the invention include: depending on the radius of the substrate, different amounts of chemistry are applied in the radial direction or different timing of the application of the chemistry is applied to achieve non-uniform removal (or different amounts of removal). This can be achieved by: different amounts of chemicals are used that are delivered to locations on the pad corresponding to a target radius of the substrate from which the film is to be removed, while the non-removal chemicals are applied to (or different chemicals are applied to) areas of the substrate corresponding to areas of the substrate that will not undergo film removal. For example, areas of the substrate where less removal is desired may have more additives (e.g., inhibitors) added to corresponding areas of the pad. Similarly, less oxidant may be supplied to this zone, or, depending on the effect of the water on removal, more or less deionized water may be present. Similarly, less abrasive slurry may be supplied to this region, or a more dilute slurry may be supplied to this region.

In some alternative embodiments, a pad smaller than the substrate may be used, and localized motion of the pad may be used to remove material in the presence of the slurry. The concepts of the Atomic Layer Polishing (ALP) embodiments described above can be implemented to provide additional control over the localized removal process. For example, by applying the removal chemistry only to the central region of a smaller polishing pad positioned at the center of the rotating substrate, the effective diameter of the pad used to remove material can be made smaller than the actual diameter of the polishing pad. Furthermore, if a smaller polishing pad is disposed at an offset from the center of the rotating substrate, the annular region between the inner and outer diameters may be isolated for material removal. The width of the annular removal zone may be controlled based on the radius of the pad area to which the removal chemistry is applied.

In some other alternative embodiments, fixed polishing pads having shapes other than circular shapes may be used. For example, to compensate for varying rotational speeds at different radii of the rotating substrate, a wedge-shaped pad (wedge-shaped pad) may be used to polish the rotating substrate. In other words, a wedge-shaped pad may be used to ensure that a region of the substrate that is relatively fast rotating (e.g., closer to a large radius of the foreign object) experiences exposure to removal chemistry on the pad equal to a region that is relatively slow moving (e.g., closer to a small radius of the center of the rotating substrate).

These and other aspects of embodiments of the invention are described below with reference to fig. 1A-13 herein.

Fig. 1A-1C illustrate various views of a substrate polishing apparatus 100 and its components. The substrate polishing apparatus 100 is adapted to hold and polish a substrate 101, as will be apparent from the following description. The substrate polishing apparatus 100 includes a polishing platen 102 having two or more solid zones (zones), such as a first zone 104, a second zone 106, and a third zone 108. The two or more zones (e.g., 104, 106, and 108) are adapted to contain different slurry compositions with different chemicals (chemical compositions). The two or more zones may be arranged across the width "W" of the platform 102. In the depicted embodiment, nine zones are shown. However, a greater or lesser number of zones may be provided. There may be multiple zones that are not adjacent but contain slurry components with the same chemistry. In the depicted embodiment, the platen 102 comprises a linear polishing platen, wherein the two or more zones are arranged across a width "W" of the pad 109 and extend along a length "L" of the pad, wherein the length L is substantially longer than the width W. In the depicted embodiment, the pad 109 of the platform 102 moves linearly as indicated by the directional arrow 110.

During the polishing method, various slurry components (such as slurry component 1, slurry component 2, and slurry component 3) may be applied to the pad 109 by the dispenser 112. The distributor 112 may have any suitable internal structure capable of distributing the slurry components to two or more zones (e.g., to zones 104, 106, 108). Slurry component 1, slurry component 2, and slurry component 3 may be received from slurry component supplies 114, 116, 118, respectively, for example. Greater or lesser amounts of the slurry components may be provided. The supply of the slurry components to the distributor 112 may be accomplished by a distribution system having one or more suitable pumps or other flow control mechanisms 115 (e.g., valves 115R). As used herein, "slurry composition" means a processing medium adapted to perform one or more specified polishing functions. In some embodiments, a rinse liquid (e.g., deionized water) may be provided from a rinse liquid source 123 and injected between two or more of the plurality of zones (such as between zones 104 and 106; or between 106 and 108; or both zones 104 and 106 and 108). Any suitable configuration of distributor 112 may be used to achieve this separation of zones 104, 106, 108 by flushing the liquid zone.

For example, slurry composition 1 may include a material adapted to perform a surface modification function, such as oxidation or other surface modification, such as formation of a nitride, bromide, chloride, or hydroxide-containing layer. Slurry composition 1 may comprise a liquid carrier such as purified water and an oxidizing agent such as hydrogen peroxide, ammonium persulfate, or potassium iodate. Other surface modifying materials may be used. Slurry component 1 can be provided from component supply 1114 to first zone 104 of pad 109 through, for example, first channel 119A (fig. 3G) of dispenser 112.

The slurry composition 2 may comprise a material adapted to perform a material removal function. The slurry composition 2 may comprise a liquid carrier such as purified water and an abrasive medium such as silica or alumina. The abrasive may have an average particle size between about 20 nanometers and 0.5 microns. Other particle sizes may be used. Slurry composition 2 may also include an etchant material, such as a carboxylic acid or an amino acid. Other etchant or complexing agent (complexing agent) materials may be used. The slurry component 2 may be supplied from the component supply 2116 to the second zone 106 of the pad 109, for example, through the second channel 119B (fig. 3F) of the distributor 112.

In one or more embodiments, the slurry composition 3 may include a material adapted to perform a corrosion-inhibiting function. Slurry component 3 may comprise a liquid carrier such as purified water and a corrosion inhibitor such as benzotriazole or 1,2, 4-Triazole (1,2, 4-Triazole). Slurry ingredients 3 can be supplied from the ingredient supply 3118 to the third zone 108 of the pad 109, for example, through the third passage 119C (fig. 3E) of the dispenser 112.

The zones 104, 106, 108 may be arranged in a side-by-side (side by side) manner and may each have a width of between about 2mm and 50 mm. These widths may be the same as or different from each other. Other widths may be used.

In one or more embodiments, a dispensing system including a dispenser 112 is adapted to dispense at least two different slurry components into two or more zones (e.g., zones 104, 106). The slurry ingredients may be selected from the group consisting of: surface modifying slurry compositions and material removal slurry compositions as discussed above.

In one or more embodiments, the distributor 112 can be formed as a unitary component and can be positioned adjacent to the pad 109 (e.g., directly above the pad 109). Distributor 112 may provide for the delivery of multiple slurry components simultaneously through two or more outlets (e.g., through outlets 121A, 121B, and 121C). For example, as shown in fig. 3A-3G, the dispenser 112 may be part of a dispensing system that may include a plurality of channels, such as a first channel 119A that extends along the length of the dispenser body 117. The first channel 119A is adapted to dispense slurry component 1 from the component 1 supply 114 to one or more first dispensing outlets 121A, the first dispensing outlets 121A being fluidly coupled to the first channel 119A along a length of the first channel 119A.

Distributor 112 may also include a second channel 119B extending along the length of distributor body 117 and adapted to distribute slurry components 2 from component 2 supply 116 to one or more second distribution outlets 121B, which second distribution outlets 121B are fluidly coupled to second channel 119B along the length of second channel 119B.

The distributor 112 may also include a third channel 119C extending along the length of the distributor body 117 and adapted to distribute slurry ingredients 3 from the ingredients 3 supply 118 to one or more second distribution outlets 121C that are fluidly coupled to the third channel 119C along the length of the third channel 119C. Other passageways and interconnected outlets may be provided to dispense other slurry components and/or flushing liquids.

In some embodiments, the rinsing liquid may be received in a separate separation zone to separate the dispensed slurry components. The outlets 121A, 121B, 121C may have a diameter of less than about 5mm, or in some embodiments between about 1mm and 15 mm. The spacing (e.g., the spacing between adjacent outlets) may be less than about 50mm, less than about 25mm, or even less than about 10mm in some embodiments. In some embodiments, the spacing may be between about 2mm and 50 mm. Other diameters and spacings may be used.

In other embodiments, the dispenser may consist of separate dispenser heads, one for each slurry component that may be disposed at different spatial locations on the pad 109. The flushing liquid (e.g., DI (deionized) water) may be delivered through some or all of the outlets 121A-121C, or through a separate outlet specifically designed for the flushing liquid. Flushing liquid may be provided from the flushing liquid supply 123 to some or all of each of the outlets 121A-121C by controlling the valve 115R. Optionally, the rinsing liquid may be provided from the dispenser 112 through a separate dispenser head or a separate outlet.

In another embodiment, the dispenser may be included in the pad holder 127 of the platform 102. In this embodiment, slurry components 1,2, 3 may be dispensed from below the pad 109 to the various zones 104, 106, and 108. The pad support 127 can include holes similar to the outlets 121A-121C in the distributor 112 that are arranged across the width of the pad 109. Each of the apertures may be fluidly coupled to one of the slurry composition supplies 114, 116, 118. As the pad 109 is rotated on the rollers 124, 126, the various separated slurry components 1,2, 3 can pass through the holes and wick (wick through) through the pad 109, which contains an internal porous structure of connected open pores. The wicking provides slurry ingredients 1,2, 3 to one or more zones 104, 106, 108, respectively. Irrigation liquid may also be dispensed through some or all of the holes.

Referring again to fig. 1A-1C, the substrate holder 120 of the substrate polishing apparatus 100 may be rotated while the slurry composition is being supplied to the zones 104, 106, 108 of the pad 109. The substrate holder 120 is adapted to hold the substrate 101 in contact with the pad 109 and rotate the substrate 101 as polishing occurs. Other motions may be provided in addition to or instead of rotation, such as orbital motion. For example, the rotational speed may be between about 10-150 RPM. Rotation may be achieved by driving the holder 120 with a holder motor 122. Any suitable motor may be used. The pressure exerted on the substrate 101 during polishing may be, for example, between about 0.1psi and 1 psi. Any suitable conventional mechanism for applying pressure may be used, such as a spring-loaded mechanism or other suitable vertically acting actuator. Other rotational speeds and pressures may be used. Substrate holders (also referred to as holders or carrier heads) are described, for example, in U.S. patent nos. 8,298,047, 8,088,299, 7,883,397 and 7,459,057, issued to the current assignee.

As slurry components 1,2, 3 are applied to the respective zones 104, 106, 108, the pad 109 may be moved in the direction of arrow 110. The linear velocity at which the pad 109 moves in the direction of arrow 110 may be, for example, between 40cm/sec and about 600 cm/sec. Other speeds may be used. The pad 109 can be provided in the form of a continuous or endless belt, as best shown in fig. 1B and 1C. The pad 109 may be supported by the first and second rollers 124, 126 (e.g., cylindrical rollers) at the ends of the pad 109 and by a pad mount 127 that spans the width of the pad 109 below the top portion of the pad 109. For example, the rollers 124, 126 are supported for rotation on the frame 128 by bearings or bushings or other suitable low friction devices. One of these rollers, such as the roller 126, may be coupled to a pad drive motor 130, which pad drive motor 130 may be driven at an appropriate rotational speed to achieve the linear polishing speed of the pad 109 described above. The pad supports 127 may also be coupled to the frame 128 at one or more locations and may support an upper portion of the pad 109 below some or all of the length L of the upper surface of the pad 109.

In addition to the rotation of the substrate holder 120 and the movement of the pad 109, the holder 120 may be translated in the direction of directional arrow 132. The translation may be a reciprocating oscillation in a transverse direction of directional arrow 132 generally perpendicular to the linear motion of the pad 109. The translation may be caused by any suitable translation motor 134 and drive system (not shown) that moves the substrate holder 120 back and forth along support rods 136. The drive system adapted to effect the translation may be a rack and pinion (pinion), a chain and sprocket (sprocket), a belt and pulley (pully), a drive and ball screw, or other suitable drive mechanism. In other embodiments, the orbital motion may be provided by a suitable mechanism. The rotation of the pad 109, the rotation and translation (e.g., oscillation) of the substrate holder 120, and the dispensing flow of the slurry components 1,2, and 3 and the rinsing liquid 123 may be controlled by a controller. The controller 138 may be any suitable computer and connected drives and/or feedback components adapted to control such movements and functions.

The pad 109 can be made, for example, of a suitable polishing pad material. The pad 109 may be a polymeric material, such as polyurethane, and may have an open surface porosity (open surface porosity). The surface porosity may be open porosity (open porosity) and may have an average pore size of between about 2 microns and 100 microns, for example. The pad may have a length L, for example, between about 30cm and 300cm as measured between the centers of the rollers 124, 126. Other dimensions may be used.

Fig. 2A and 2B illustrate various views of an alternative embodiment of a substrate polishing apparatus 200 and its components. As before, the substrate polishing apparatus 200 is adapted to hold and polish a substrate 101, as will be apparent from the following description. The substrate polishing apparatus 200 includes a polishing platen 202 having a pad 209 and a pad holder 227 (e.g., a platen). The polishing platform 202 has two or more solid regions, such as a first region 204 and a second region 206, and even a third region 208. The zones 204, 206, 208 in this embodiment are arranged as concentric rings and the platform 202 is rotatable.

Each zone 204, 206, 208 is adapted to contain a different slurry composition with a different chemical, such as slurry compositions 1-3 described above. The slurry components may be distributed to the various zones 204, 206, 208 by distributors 212 coupled to the component supplies 114, 116, 118 via valves or other flow control mechanisms in a manner controlled by a controller 238 as previously described. Two or more zones 204, 206, 208 may be arranged across the diameter "D" of the platform 202. Each annular region may have the same or different width, and may be as described above. In the depicted embodiment, nine annular zones are shown. However, a greater or lesser number of zones may be provided. Further, there may be multiple zones that are not adjacent to each other but contain slurry components having the same chemical (e.g., chemical composition). For example, each of the zones labeled 204 may receive and contain the same slurry chemistry. Each of the zones labeled 206 can receive and contain the same slurry chemistry and each of the zones labeled 208 can receive and contain the same slurry composition chemistry. However, the chemicals in each of zones 204, 206, and 208 may have different slurry composition chemicals relative to each other.

In the depicted embodiment, the platen 202 comprises a rotary polishing platen in which two or more zones (e.g., zones 204, 206 or 204, 206, and 208) are arranged across the diameter D of the pad 209. The platform 202 and pad 209 may be rotated in the direction of directional arrow 210 by a platform motor 230 at a rotational speed of between about 10RPM and about 200 RPM. As before, the substrate holder 220 may be rotated by a suitable holder motor 222 to rotate the substrate 101 as polishing occurs. The rotational speed of the retainer 220 may be, for example, between about 10RPM and 200 RPM. Similarly, the holder 220 can be reciprocally translated (e.g., oscillated) in a lateral direction 232 that is generally perpendicular to the tangential motion of the pad 209. The translation may be caused by any suitable transfer motor 234 and drive system (not shown), as described above.

The pressure exerted on the substrate 101 during polishing may be, for example, as discussed above. Any suitable conventional mechanism for applying pressure may be used, such as a spring-loaded mechanism or an actuator. Other rotational speeds and pressures may be used. The substrate holder 220 may be, for example, as described in the following patents: US patent nos. 8,298,047, US8,088,299, US 7,883,397 and US 7,459,057.

Fig. 4 depicts a method 400 of processing a substrate, such as substrate 101, and in particular a method of polishing a surface, such as a front side or backside surface, of a substrate 101, such as a patterned or unpatterned wafer. The method 400 includes the steps of: in 402, a substrate is provided in a substrate holder (e.g., substrate holder 120, 220); at 404, providing a polishing platform (e.g., polishing platform 102, 202) having a movable polishing pad (e.g., polishing pad 109, 209); and at 406, dispensing different slurry compositions into two or more zones (e.g., zones 104, 106, 108) on the polishing pad. The polishing pad can be a linearly moving version of the pad 109 or a rotationally moving version of the pad 209. The slurry components can be dispensed to a region (e.g., domains 104, 106, 108) above the pad 109 or below the pad 109 (e.g., by wicking or other capillary action).

In another aspect, a substrate polishing system is provided as described in any of fig. 1A-1C or fig. 2A and 2B. The substrate polishing system includes: an apparatus 100, 200 having a polishing holder 120, 220 adapted to hold a substrate 101; a polishing platen 102, 202 having a polishing pad 109, 209 movable relative to the substrate 101; and a dispensing system adapted to dispense at least two different slurry ingredients selected from the group consisting of: an oxidizing slurry component, a material removal slurry component, and a corrosion inhibiting slurry component. In this regard, the two or more slurry components are dispensed one after the other in a timed sequence, rather than being dispensed into multiple zones arranged across the width W or diameter D of the pad 109, 209.

In accordance with this aspect, a first slurry component selected from the group consisting of an oxidizing slurry component, a material removal slurry component, and a corrosion inhibiting slurry component is first dispensed onto the pad (e.g., pad 109, 209). After a predetermined amount of time has elapsed, the supply of the first slurry component is stopped, and a second slurry component selected from the group consisting of an oxidizing slurry component, a material removal slurry component, and a corrosion-inhibiting slurry component may then be dispensed onto the pad (e.g., pad 109, 209). After another predetermined amount of time has elapsed, the supply of the second slurry component is stopped, and a third slurry component selected from the group of oxidizing slurry components, material removing slurry components, and corrosion inhibiting slurry components may then be dispensed onto the pad (e.g., pad 109, 209). This timing sequence may be restarted again by re-dispensing the first slurry component after a third predetermined amount of time has elapsed. This sequence may be repeated as many times as necessary to achieve a desired result (such as a desired amount of film removal). After the polishing sequence, the pad 109, 209 may be rinsed by supplying a rinsing liquid to the pad 109, 209.

Fig. 5 and 6 illustrate another method 500 of polishing a substrate. The method 500 includes the steps of: in 502, a substrate (e.g., substrate 101) is provided in a substrate holder (e.g., holder 120, 220); and at 504, providing a polishing platform having a movable polishing pad. At 506, the method comprises the steps of: two or more slurry components, each having a different chemical composition, are dispensed between the polishing pad and the substrate in a timed sequence.

As shown in fig. 6, the slurry components can be dispersed between the pads (e.g., pads 109, 209) and the substrate 101 in the timing sequence shown. In a first time increment 650, a first slurry component (e.g., an oxidizing slurry component) can be supplied. Followed by a second slurry composition (e.g., a material removal slurry composition) being supplied for a second time increment 651. The chemical composition of the first and second slurry components are different. Followed by providing a third slurry composition (e.g., a corrosion inhibiting slurry composition) for a third time increment 652. Two or more of these distribution phases may be repeated 653- ­ 655. Other stages may be performed in addition to or in place of these stages. These three or more dispense sequences may be repeated as many times as desired on a single substrate. This may be performed while oscillating and rotating against the moving pad (e.g., pad 109, 209) as described above. After these polishing stages are completed, in 656, the pad (e.g., pad 109, 209) may undergo a rinsing stage in which the pad (e.g., pad 109, 209) may be supplied with a rinsing liquid (e.g., DI water or other inert liquid solution). The dispensing of a rinse liquid (e.g., deionized water) may be used to dilute the last applied chemical. Subsequently, the method 500 may stop, a new substrate may be placed in the substrate holder (e.g., substrate holder 120, 220), and the described method 500 may be implemented on a second substrate starting at 657.

Each of these stages may take between about 1 second to about 60 seconds. Other durations may be used. Some of the pulses may be less than 1 second. Each stage may have the same or different length. In some embodiments, some of the slurry components may be combined to make up more than one treatment stage in a single pulse. For example, in some embodiments, the oxidation and corrosion inhibitor stages may be combined into one slurry component and provided as a single pulse. In other embodiments, a complexing agent (complexing agent) may be combined with an abrasive (e.g., a metal oxide abrasive) in a single pulse. The oxidizing agent may be hydrogen peroxide. The corrosion inhibitor may be a triazole. The complexing agent may be an organic acid, an organic acid salt, or an amino acid. Other types of oxidizing agents, corrosion inhibitors, complexing agents, and abrasives may be used.

Fig. 6 depicts another embodiment of a method 600 that utilizes a series of slurry ingredients dispensed in a timed sequence (e.g., dispensed as pulses of multiple individual slurry ingredients). The use of time-separated introduction of polishing chemicals allows for increased flexibility in the use of the chemicals (e.g., two or more slurry components). For example, oxidizing chemicals are generally self-limiting. The surface film may be oxidized to a depth of about 20 angstroms and then stopped. By separating the various slurry components over time, more aggressive oxidizing chemicals may be used where the depth of oxidation may be controlled by the pulse length of the chemical slurry components supplied to the substrate.

In particular, a plurality of individual stages may be specified to affect a particular reaction to form a modified layer on the surface of the substrate. In some conventional material removal processes, the system uses a slurry polishing agent that inhibits removal at lower polishing pressures. These previous polishing systems may provide better control of in-die (WID) thickness because once the topography is removed, the removal rate is greatly reduced. As a result, the topography having a low density in areas of the die is quickly removed, and then dielectric removal stops while topography removal in other areas of the die continues to polish until these areas are planarized. However, these systems suffer from very low removal rates (by design) once the main profile has been planarized. These systems may also suffer from large features being incompletely removed. A multi-step method of staged (e.g., timed) introduction of multiple slurry components (e.g., additives, abrasives without additives, and possibly interspersed rinsing and/or subsequent rinsing) according to an aspect of the invention may be used to overcome these previous limitations. For example, the additive may be introduced first, followed by an abrasive solution that dilutes the additive and allows for limited film removal. Additional removal can be achieved by introducing a rinse that can rapidly dilute the additive and allow for limited film removal until the load (charge) of abrasive slurry components is exhausted.

Examples of multi-step methods and systems are provided below. The method may be useful for metal film removal and may include an oxidation stage involving film oxidation and an inhibitor adsorption and complexing agent assisted attrition stage to the oxidized surface, which are performed in a sequential manner to achieve film removal for each reaction cycle. In this embodiment, as shown in fig. 7, each of the slurry components can be dispensed between the pads (e.g., pads 109, 209) and the substrate 101 in a timed sequence, but a rinse phase is established between the dispensing of each slurry component. Thus, each pulse of slurry components (e.g., oxidizing agent, inhibitor, complexing agent, material remover) may be separated by a pulse of rinsing agent (e.g., DI water) in order to rinse the pad (e.g., pads 109, 209) and the surface of the substrate 101.

Specifically, in a first time increment 650, a first slurry composition (e.g., an oxidizer slurry composition) may be supplied. This is followed by a rinse in 657. Subsequently, a second slurry composition (e.g., a material removal slurry composition) may be dispensed for a second time increment 652. This may be followed by another rinse in 657. The chemical composition of the first and second slurry components are different. The second rinse 657 may be followed by a third slurry composition (e.g., a corrosion-inhibiting slurry composition) for a third time increment 653. This may be followed by another rinse in 657. After this sequence is complete, the sequence may be repeated as many times as necessary on the same substrate 101 to achieve the desired material removal, or a new substrate may be inserted in the substrate holder (e.g., 120, 220), and polishing of the substrate by the method 700 may begin on this new substrate. The number of times for each stage of the polishing process may be the same or different.

Other steps may be used in this sequence, such as an inhibitor adsorption stage and a complexation attrition stage. In some embodiments, two or more of these stages may be combined. The relative duration of each phase may be determined based on the reaction kinetics (reaction kinetics) of that particular phase. For example, the oxidation phase may be relatively short for copper polishing, while the oxidation phase may be relatively long for polishing ruthenium or more noble metals. The pulse duration of the corrosion inhibitor phase (including inhibitor adsorption) may also vary in length based on the kinetics of adsorption. Similarly, the complexation-attrition phase may change length based on its kinetics. In some embodiments, a pulse of oxidizing slurry constituents (e.g., oxidizing solution) may be followed by a pulse of corrosion inhibitor slurry constituents (e.g., inhibitor solution) followed by a pulse of complexing slurry constituents (e.g., complexing agent). These sequenced pulses may be provided while the substrate 101 is being pressed against the moving surface of the pad (e.g., pads 109, 209).

Another example of staged introduction of slurry components in a timed sequence is described below. A copper film removal process is provided in which a first pulse of the combined slurry components of the oxidizer and inhibitor solutions is followed by a separate pulse of the complexing agent while the substrate (e.g., wafer) is being pressed against the moving surface of the pad (e.g., pad 109, 209), as described herein. In some embodiments, pulses of the combined slurry components of the oxidizer and inhibitor solutions and separate pulses of the complexing agent may be interspersed by flushing pulses of the flushing liquid. Optionally, the flush pulse may be at the end of this two-stage sequence.

In another method embodiment adapted for metal oxide film polishing and removal, the two-stage method includes a first pulse of oxidizing slurry composition, which may be followed by separate consecutive pulses of slurry composition having a combination of metal oxide abrasive and complexing agent. Optionally, the complexing agent slurry component and the metal oxide abrasive slurry component can be formulated as separate stages one after the other in a three-stage polishing process. The flush phase may be established between multiple phases or at the end of a sequence.

One significant advantage of the time-series introduction of slurry constituents is that each step or pulse can be self-limiting, which can result in relatively more uniform removal of even small thicknesses (particularly less than 500 angstroms, and especially less than 200 angstroms). For example, once the surface oxidation phase of a surface (e.g., a copper surface) is completed to several atomic layers (between about 25-30 angstroms), the oxidation rate can be significantly slowed. Thus, when the complexation-attrition stage is then performed, film removal can be automatically limited to about 25 to 30 angstroms, regardless of the length of the stage, and film removal uniformity can become relatively independent of removal rate.

In each of the methods described herein, the distribution of the slurry components may be provided by the systems and apparatuses described herein. Optionally, other suitable systems adapted to perform timed sequential delivery of slurry components and possible flushes may be used.

Turning now to fig. 8 and 9, cross-sectional profile examples before and after portions of a substrate 101 are intentionally unevenly polished are depicted, in accordance with embodiments of the present invention. In FIG. 8, prior to non-uniform polishing, a film 802 on a substrate 101 has a relatively uniform thickness 804. As depicted in fig. 9, after the non-uniform ALP method of the present invention is applied, the thickness of the film 802 in the target material removal region 904 has been reduced by a desired amount 902, while the film 802 remains at the original thickness 804 in the non-target region 906. Fig. 10 depicts a top view of the substrate 101 after non-uniform polishing, which depicts a target material removal region 904 and a non-target region 906. Note that the diameter of the non-target region 906 may be any desired size, as will be described in further detail below.

Fig. 11 depicts an example of a non-uniform substrate polishing apparatus 1100, the non-uniform substrate polishing apparatus 1100 being similar to the example substrate polishing apparatus 100 described above, but adapted to remove more layers of the target material removal region 904 (fig. 9) without removing material from the non-target region 906 (fig. 9). The example non-uniform substrate polishing apparatus 1100 is adapted to hold and polish a substrate 101 as described above with reference to fig. 8-10. The non-uniform substrate polishing apparatus 1100 includes a polishing platform 1102, the polishing platform 1102 having two or more physical regions, such as a first region 1104, a second region 1106, and a third region 1108. The two or more zones (e.g., 1104, 1106, and 1108) are adapted to contain different slurry chemistries having different chemistries (chemical compositions). The two or more regions may be arranged across the width of the platform 1102. In the depicted example embodiment, eight zones are shown. However, a greater or lesser number of zones may be provided. In various embodiments, there may be multiple zones that are not adjacent but contain slurry chemicals with the same chemical. In the depicted embodiment, the platen 1102 comprises a linear polishing platen, wherein the two or more regions are arranged across a width of the pad 1109 and extend along a length of the pad, wherein the length is substantially greater than the width. In the depicted embodiment, the pad 1109 of the platform 1102 moves linearly, as indicated by directional arrow 1110.

During this polishing method, various slurry chemistries, such as slurry chemistry 1, slurry chemistry 2, and slurry chemistry 3, can be applied to the pad 1109 by the dispenser 1112. The distributor 1112 can have any suitable internal structure capable of distributing the slurry components to the two or more zones (e.g., to zones 1104, 1106, 1108). The slurry chemical 1, the slurry chemical 2, and the slurry chemical 3 may be received from slurry chemical supplies 1114, 1116, 1118, respectively, for example. Greater or lesser amounts of slurry chemicals may be provided. The supply of slurry chemicals to the dispenser 1112 can be accomplished by a dispensing system having one or more suitable pumps, manifolds, valves, or other flow control mechanisms 1115 under the control of a controller 1138 (e.g., a processor, computer, or other operating system management system adapted to execute instructions adapted to implement the methods disclosed herein).

Flow control mechanism 1115 is further adapted to allow any of chemicals 1,2, 3 or rinse liquids, or any combination thereof, to be supplied to any of the multiple channels of dispenser 1112 at different times. Thus, in some embodiments, the non-uniform substrate polishing apparatus 1100 may deliver any combination of any of slurry chemistry, slurry composition, and rinsing liquid to any number or arrangement of desired zones (e.g., zones 1104, 1106, 1108) at any given time. As used herein, "slurry chemistry" is intended to mean one or more slurry components that can be used to perform material removal from (e.g., at various rates) or to preserve material on a substrate. In some embodiments, a rinse liquid (e.g., deionized water) may be provided from a rinse liquid source 1123 and may be injected between two or more of the zones (such as between zones 1104 and 1106; or between 1106 and 1108; or between both zones 1104 and 1106 and 1108). Any suitable configuration of the distributor 1112 may be used to achieve this separation of the regions 1104, 1106, 1108 by the rinse liquid region.

For example, in one or more embodiments, the slurry chemistry 1 can include a material adapted to perform a corrosion-inhibiting function. Slurry chemistry 1 can include a liquid carrier (such as purified water) and a corrosion inhibitor (such as benzotriazole, or 1,2,4 triazole). Slurry chemistry 1 can be supplied from a chemistry 1 supply 1114 to the first region 1104 of the pad 1109, for example, through a first channel of a dispenser 1112.

Slurry chemistry 2 and slurry chemistry 3 can include materials adapted to perform both a surface modification function and a material removal function simultaneously. For example, the surface modification function may include oxidation or other surface modification, such as the formation of a nitride, bromide, chloride, or hydroxide containing layer. Slurry chemicals 2 and 3 may include a liquid carrier (such as purified water) and an oxidizing agent (such as hydrogen peroxide, ammonium persulfate, or potassium iodate). Other surface modifying materials may be used. Slurry chemistry 2 and slurry chemistry 3 can also include an abrasive media (such as silica or alumina). The abrasive may have an average particle size between about 20 nanometers and 0.5 microns. Other particle sizes may be used. Slurry chemistry 2 and slurry chemistry 3 can also include etchant materials such as carboxylic acids or aminocarboxylic acids. Other etchant or complexing agent materials may be used.

In some embodiments, slurry chemistry 2 and slurry chemistry 3 may be the same, in other embodiments, chemistry 3 may include, for example, a more aggressive etchant and/or abrasive to remove material more quickly than chemistry 2. Such embodiments allow for the creation of target material removal regions having different film thicknesses. Slurry chemistry 2 and slurry chemistry 3 can be supplied from the chemistry 2 supply 1116 and the chemistry 3 supply 1118 through, for example, second and third channels of the dispenser 1112 to the second and third zones 1106, 1108 of the pad 1109.

The regions 1104, 1106, 1108 can be arranged in a side-by-side manner and each can have a width of between about 2mm and 50 mm. These widths may be the same or different from each other. Other widths may be used.

In one or more embodiments, a dispensing system including a dispenser 1112 is adapted to dispense at least two different slurry chemistries into two or more zones (e.g., zones 1104, 1106). In some embodiments, the slurry chemistry may be selected from the group consisting of: the material preserves the slurry chemistry, slow material removal slurry chemistry, and aggressive material removal chemistry, as discussed above.

In one or more embodiments, the distributor 1112 can be formed as a unitary component and can be positioned adjacent to the pad 1109 (e.g., directly above the pad 1109). The dispenser 1112 may provide for the delivery of the slurry chemical simultaneously through two or more outlets. For example, the distributor 1112 may be part of a distribution system that may include a plurality of channels.

In some embodiments, the rinse liquid may be received in a separate separation zone to separate the sent slurry components. The outlet may have a diameter of less than about 5mm, or in some embodiments between about 1mm and 15 mm. The spacing (e.g., the spacing between adjacent outlets) may be less than about 50mm, less than about 25mm, or even less than about 10mm in some embodiments. In some embodiments, the spacing may be between about 2mm and 50 mm. Other diameters and spacings may be used.

In other embodiments, the dispenser may consist of separate dispenser heads, one for each slurry chemical that may be disposed at different spatial locations on the pad 1109. The rinse liquid (e.g., DI water) may be delivered through some or all of the outlets, or through a separate outlet designed specifically for rinse. The rinsing liquid may be provided from the rinsing liquid supply 1123 to some or all of each of the outlets. Optionally, the rinsing liquid may be provided from the dispenser 1112 through a separate dispensing head or a separate outlet.

In some embodiments, the dispenser may be included in a pad holder 1127 of the platform 1102. In such embodiments, slurry chemistries 1,2, 3 may be dispensed to the various zones 1104, 1106, and 1108 from below the pad 1109 or through the pad 1109. The pad support 1127 may include holes like outlets in the distributor 1112 arranged across the width of the pad 1109. Each of the holes may be fluidly coupleable to one of the slurry chemical supplies 1114, 1116, 1118. As the pad 1109 is rotated on rollers 1124, 1126, the various separated slurry chemistries 1,2, 3 can pass through these apertures and wick through the pad 1109, which contains an internal porous structure of connected open pores. Wicking provides slurry chemicals 1,2, 3 to one or more zones 1104, 1106, 1108, respectively. Irrigation liquid may also be dispensed through some or all of the holes.

Still referring to FIG. 11, the substrate holder 1120 of the non-uniform substrate polishing apparatus 1100 may be rotated while slurry chemistry is being supplied to the zones 1104, 1106, 1108 of the pad 1109. The substrate holder 1120 is adapted to hold a substrate in contact with the pad 1109 and rotate the substrate as polishing occurs. Other motions may be provided in addition to or instead of rotation, such as orbital motion. In some embodiments, the rotational speed may be, for example, between about 10-150 RPM. Other speeds may be used. Rotation may be achieved by driving the holder 1120 with the holder motor 1122. Any suitable motor may be used. The pressure exerted on the substrate during polishing can be, for example, between about 0.1psi and 1 psi. Other pressures may be used. Any suitable conventional mechanism for applying pressure may be used, such as a spring-loaded mechanism or other suitable vertically acting actuator. Substrate holders (also referred to as holders or carrier heads) are described, for example, in U.S. patent nos. 8,298,047, 8,088,299, 7,883,397 and 7,459,057, issued to the current assignee.

As slurry components 1,2, 3 are applied to respective zones 1104, 1106, 1108, pad 1109 may be moved in the direction of arrow 1110. The linear velocity of movement of the pad 1109 in the direction of arrow 1110 can be, for example, between about 40cm/sec and about 600 cm/sec. Other speeds may be used. The pad 1109 can be provided in the form of a continuous or endless belt. The pads 1109 may be supported at the ends of the pads 1109 by rollers 1124, 1126 (e.g., cylindrical rollers) and below the top portion of the pads 1109 by pad supports 1127 that span the width of the pads 1109. For example, the rollers 1124, 1126 are supported for rotation on the frame 1128 by bearings or bushings or other suitable low friction devices. One of these rollers, such as roller 1126, may be coupled to a pad drive motor 1130, the pad drive motor 1130 being capable of being driven at an appropriate rotational speed to achieve the linear polishing speed of the pad 1109 described above. The pad supports 1127 may also be coupled to the frame 1128 at one or more locations and may support an upper portion of the pad 1109 below some or most of the length of the upper surface of the pad 1109.

In addition to the rotation of the substrate holder 1120 and the motion of the pad 1109, the holder 1120 may be translated in the direction of directional arrow 1132. The translation may be a reciprocating oscillation in a transverse direction of directional arrow 1132 that is generally perpendicular to the linear motion of pad 1109. Unlike in the operation of the substrate polishing apparatus 100 described above with reference to fig. 1A, any translation of the holder 1120 in the operation of the example non-uniform substrate polishing apparatus 1100 will be limited to avoid removing material from non-target areas. However, in some embodiments, translation of the holder 1120 may be used to adjust the size of the target material removal area or the initial positioning of the substrate relative to the plurality of areas.

Translation may be implemented using any suitable translation motor 1134 and drive system (not shown) that moves the substrate holder 1120 back and forth along support bar 1136. The drive system adapted to effect the translation may be a rack and pinion, a chain and sprocket, a belt and pulley, a drive and ball screw, or other suitable drive mechanism. In other embodiments, the orbital motion may be provided by a suitable mechanism. Rotation of the pad 1109, rotation and translation (e.g., oscillation) of the substrate holder 1120, and the dispensing flow of slurry chemistries 1,2, and 3 and rinse liquid 1123 may be controlled by the controller 1138. The controller 1138 may be any suitable computer and connected drives and/or feedback components adapted to control such movements and functions.

The pad 1109 may be fabricated from, for example, a suitable polishing pad material. The pad 1109 may be a polymeric material (such as polyurethane) and may have an open-celled surface porosity. The surface porosity may be open porosity and may have an average pore size of between about 2 microns and 100 microns, for example. The pad may have a length, for example, between about 30cm and 300cm as measured between the centers of the rollers 1124, 1126. Other dimensions may be used.

Similar to the embodiment depicted in fig. 2A and 2B, a rotating polishing pad embodiment of a non-uniform substrate polishing apparatus may be used. As with the linear polishing pad example embodiment depicted in fig. 11, different zones (although concentrically rather than in parallel arrangement) may be defined and adapted to receive different slurry chemistries at different times to facilitate the removal of different amounts of material from one or more selected target areas of the substrate. Thus, as with the linear polishing pad example embodiment depicted in FIG. 11, the rotary polishing pad embodiment of the non-uniform substrate polishing apparatus can be used to produce a film profile having two or more thicknesses (e.g., as shown in FIG. 9).

In some alternative embodiments, a rotating polishing pad that is smaller than the substrate may be used, and localized motion of the pad may be used to remove material in the presence of slurry applied through portions of the pad or directly to the substrate at different times corresponding to different locations of the pad. For example, by applying the removal chemistry only to the central region of a rotating polishing pad (which is smaller than the substrate and positioned at the center of the rotating substrate), the effective diameter of the pad for material removal can be made smaller than the actual diameter of the polishing pad. Furthermore, if a smaller polishing pad is disposed at an offset from the center of the rotating substrate, the annular region between the inner diameter and the radius may be isolated for material removal. The width of the annular removal region may be further controlled based on the radius of the pad region to which the removal chemistry is applied and/or by varying the offset from the center of the substrate (e.g., by radially oscillating the rotating pad).

In other example embodiments, different chemistries may be applied at different times to effect selective removal of material, the different times corresponding to different locations of the pad relative to the center of the substrate. Thus, for example, when the pad is positioned at the center of the rotating substrate, chemicals adapted for aggressive material removal may be applied to the substrate, while when the pad is positioned away from the center, chemicals adapted for relatively gentle material removal may be applied to the substrate. This example arrangement allows for the formation of a film profile that is thinner in the center of the substrate and thicker at the edges of the substrate (e.g., as opposed to the profile depicted in fig. 9).

In some other alternative embodiments, fixed polishing pads having shapes other than circular may be used. For example, to compensate for varying rotational speeds at different radii of the rotating substrate, a stationary wedge pad 1200 as depicted in fig. 12 may be used to polish a film on the rotating substrate 101 to a uniform thickness. In other words, the wedge-shaped pad 1200 may be used to ensure that a relatively quickly rotating substrate region (e.g., at a large radius closer to the outer edge, such as substrate region 1202-1212) experiences exposure to removal chemistry on the pad 1200 that is equal to a relatively slowly moving region (e.g., at a small radius closer to the center of the rotating substrate 101, such as substrate region 1214-1226). In some embodiments, the wedge pad 1200 may include an arrangement of slurry delivery apertures 1201 or channels configured to distribute an amount of slurry proportional to the perimeter of the substrate region 1202 and 1226 being polished.

In non-uniform polishing applications, a stationary wedge-shaped pad 1200 as depicted in fig. 12 may be used to create a membrane profile with different desired thicknesses at each substrate zone 1202-1226 based on the chemistry of the slurry delivered to the pores 1201 corresponding to each substrate zone 1202-1226. In other words, the chemical having the first function may be applied to a group of pores that only contact a particular substrate region (e.g., substrate region 1202). Meanwhile, a chemical having a second function may be applied to a group of pores that only contact a different substrate region (e.g., substrate region 1204). At the same time, a chemical having a third function may be applied to a group of pores that only contact yet a different substrate region (e.g., substrate region 1206), and so on. Thus, each substrate region 1202-1226 may be subjected to different chemistries to produce a desired film thickness profile. Furthermore, different chemicals may be applied to different substrate regions at different times.

In some embodiments, a non-uniform substrate polishing apparatus may be used to perform the various methods 1300 of the present invention. Different chemicals having different functions are separately applied to at least two different zones (1304) of the polishing pad while rotating the substrate (1302) against the moving polishing pad. Removing different amounts of material from the substrate corresponding to the at least two different regions of the polishing pad (1306). The polishing pad can be a linearly moving pad or a rotating pad. In some embodiments, the resulting film thickness profile on the substrate may have multiple thicknesses.

Thus, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the scope of the invention, as defined by the following claims.