阅读说明：本技术 用于在物理气相沉积工艺中控制离子分数的方法和设备 (Method and apparatus for controlling ion fraction in physical vapor deposition process ) 是由 晓东·王 李靖珠 张富宏 马丁·李·瑞克 基思·A·米勒 威廉·弗鲁赫特曼 汪荣军 阿 于 2017-03-03 设计创作，主要内容包括：公开用于在物理气相沉积工艺中控制离子分数的方法和设备。在一些实施方式中,用于处理具有给定直径的基板的处理腔室包括：内部容积和待溅射靶材,内部容积包括中心部分和周边部分；可旋转磁控管,处于靶材上方以在周边部分中形成环形等离子体；基板支撑件,设置在内部容积中以支撑具有给定直径的基板；第一组磁体,围绕主体设置以在周边部分中形成实质上竖直的磁场线；第二组磁体,围绕主体设置且处于基板支撑件上方以形成指向支撑表面的中心的磁场线；第一电源,用于电偏置靶材；和第二电源,用于电偏置基板支撑件。(Methods and apparatus for controlling ion fraction in a physical vapor deposition process are disclosed. In some embodiments, a process chamber for processing a substrate having a given diameter includes: an interior volume and a target to be sputtered, the interior volume including a central portion and a peripheral portion; a rotatable magnetron over the target to form an annular plasma in the peripheral portion; a substrate support disposed in the interior volume to support a substrate having a given diameter; a first set of magnets disposed around the body to form substantially vertical magnetic field lines in the peripheral portion; a second set of magnets disposed around the body and above the substrate support to form magnetic field lines directed toward a center of the support surface; a first power supply for electrically biasing the target; and a second power supply for electrically biasing the substrate support.)

1. A physical vapor deposition chamber, comprising:

a body having an interior volume and a lid assembly including a target to be sputtered;

a magnetron disposed above the target, wherein the magnetron is configured to rotate a plurality of magnets about a central axis of the physical vapor deposition chamber;

a substrate support disposed in the interior volume and opposite the target and having a support surface configured to support a substrate;

a collimator disposed between the target and the substrate support, the collimator having a central region and a peripheral region, the central region having a first thickness and the peripheral region having a second thickness less than the first thickness;

a first power supply coupled to the target to electrically bias the target; and

a second power supply coupled to the substrate support to electrically bias the substrate support.

2. The physical vapor deposition chamber of claim 1, wherein the central region of the collimator has a diameter equal to or greater than a diameter of a substrate to be supported.

3. The physical vapor deposition chamber of claim 1, wherein the collimator is disposed in an upper portion of the interior volume and the collimator is closer to the target than to the substrate support.

4. The physical vapor deposition chamber of any of claims 1-3, wherein the second power source is an RF power source.

5. The physical vapor deposition chamber of any of claims 1-3, further comprising:

a shield disposed in the interior volume, wherein the collimator is coupled to the shield.

6. The physical vapor deposition chamber of claim 5, wherein the shield comprises an upper shield and a lower shield, and wherein the collimator is coupled to the upper shield.

7. The physical vapor deposition chamber of any of claims 1-3, further comprising:

an edge ring disposed on the substrate support.

8. The physical vapor deposition chamber of claim 7, further comprising:

a shield ring configured to engage with the edge ring.

9. The physical vapor deposition chamber of any of claims 1-3, further comprising:

a set of magnets disposed around the body, the set of magnets being located above a support surface of the substrate support and below the collimator.

Technical Field

Embodiments of the present disclosure generally relate to substrate processing chambers for use in semiconductor manufacturing systems.

Background

Sputtering, also known as Physical Vapor Deposition (PVD), is a method of depositing metals in integrated circuits. Sputtering deposits a layer of material on a substrate. The source material, such as a target, is bombarded by ions that are strongly accelerated by an electric field. The bombardment causes material to be ejected from the target, and the material is subsequently deposited on the substrate. During deposition, the ejected particles may travel in different directions, rather than generally normal to the substrate surface, disadvantageously causing overhang structures formed on the corners of high aspect ratio features in the substrate. The overhang may undesirably cause voids or voids to form within the deposited material, thereby causing reduced conductivity of the formed feature. Higher aspect ratio geometries are more difficult to achieve void-free filling.

Controlling the ion fraction or ion density reaching the substrate surface to a desired range may improve bottom and sidewall coverage (and reduce overhang problems) during the metal layer deposition process. In one example, particles dislodged from the target may be controlled via a processing tool such as a collimator to facilitate providing a more vertical particle trajectory into the feature. The collimator provides a relatively long, straight and narrow channel between the target and the substrate to filter out non-vertically traveling particles that affect and adhere to the channels of the collimator.

However, the inventors have found that in some applications, the collimator may adversely affect the deposition uniformity on the substrate. Specifically, in some cases, the channel shape is imprinted (imprint) on the substrate. The inventors have further discovered that control of the ions and ion fraction (i.e., the number of ions in the plasma versus the number of neutral particles in the (vertuss) plasma) can be used to control deposition characteristics, such as uniformity, on the substrate.

Accordingly, the present inventors provide improved embodiments of methods and apparatus for controlling ion fraction in a physical vapor deposition process.

Disclosure of Invention

Methods and apparatus for controlling ion fraction in a physical vapor deposition process are disclosed. In some embodiments, a process chamber for processing a substrate having a given diameter comprises: a body having an interior volume and a lid assembly including a target to be sputtered, wherein the interior volume includes a central portion having approximately a given diameter and a peripheral portion surrounding the central portion; a magnetron disposed above the target, wherein the magnetron is configured to rotate a plurality of magnets about a central axis of the process chamber to form a ring-shaped plasma in a peripheral portion of the interior volume, and wherein a radius of rotation of the plurality of magnets is substantially equal to or greater than a given diameter; a substrate support disposed in the interior volume opposite the target and having a support surface configured to support a substrate having a given diameter; a first set of magnets disposed around the body and proximate to the target to form a magnetic field having substantially vertical magnetic field lines in the peripheral portion; a second set of magnets disposed around the body and above the support surface of the substrate support to form a magnetic field having magnetic field lines directed toward a center of the support surface; a first power supply coupled to the target to electrically bias the target; and a second power supply coupled to the substrate support to electrically bias the substrate support.

In some embodiments, a process chamber for processing a substrate having a given diameter comprises: a body having an interior volume and a lid assembly including a target to be sputtered, wherein the interior volume includes a central portion having approximately a given diameter and a peripheral portion surrounding the central portion; a magnetron disposed above the target, wherein the magnetron is configured to rotate a plurality of magnets about a central axis of the process chamber to form a ring-shaped plasma in a peripheral portion of the interior volume, and wherein a radius of rotation of the plurality of magnets is substantially equal to or greater than a given diameter; a substrate support disposed in the interior volume and opposite the target and having a support surface configured to support a substrate having a given diameter; a collimator disposed between a target and the substrate support; a first set of magnets disposed around the body and proximate to the target to form a magnetic field in the peripheral portion and having substantially vertical magnetic field lines through the collimator; a second set of magnets disposed around the body and above the support surface of the substrate support to form a magnetic field having magnetic field lines directed toward a center of the support surface; a third set of magnets disposed around the body at the same height as or below the substrate-facing surface of the collimator to form a magnetic field having magnetic field lines directed inwardly and downwardly toward the central portion and toward the center of the support surface; a first power supply coupled to the target to electrically bias the target; and a second power supply coupled to the substrate support to electrically bias the substrate support.

In some embodiments, a method of processing a substrate includes: forming a plasma within an annular region of the process chamber above the substrate and proximate the target to sputter material from the target, wherein an inner diameter of the annular region is substantially equal to or greater than a diameter of the substrate such that a substantial portion of the plasma is disposed in a position above and radially outward of the substrate; directing material sputtered from a target toward a substrate; and depositing material sputtered from the target on the substrate.

Other and further embodiments of the present disclosure are described below.

Drawings

Embodiments of the present disclosure, briefly summarized above and discussed in more detail below, may be understood with reference to the exemplary embodiments thereof that are depicted in the appended drawings. The appended drawings, however, 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. 1 depicts a schematic cross-sectional view of a processing chamber according to some embodiments of the present disclosure.

Fig. 2 depicts a top view of a collimator according to some embodiments of the present disclosure.

Fig. 3 is a flow chart depicting a method of processing a substrate according to some embodiments of the present disclosure.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of some embodiments may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

Embodiments of methods and apparatus for controlling ion fraction in a physical vapor deposition process are disclosed herein. The method and apparatus of the present invention advantageously provide better control of ions in a PVD process, thereby further advantageously facilitating control of deposition results, such as uniformity of deposition of material on a substrate. Embodiments of the apparatus and method of the present invention may also advantageously improve deposition in features in the substrate and reduce the necessary deposition rate by increasing the number of ions and reducing the number of neutral species deposited on the substrate.

Embodiments of the present disclosure are illustratively described herein with reference to a Physical Vapor Deposition (PVD) chamber. However, the methods of the present invention may be used with any processing chamber modified in accordance with the teachings disclosed herein. Fig. 1 illustrates a PVD chamber (process chamber 100), e.g., a sputtering process chamber, suitable for sputter depositing material on a substrate having a given diameter, in accordance with embodiments of the present disclosure. In some embodiments, the PVD chamber further comprises a collimator 118 disposed in the chamber and supported by the process tool adapter 138. In the embodiment shown in fig. 1, the process tool adapter 138 is a cooled process tool adapter. Illustrative examples of suitable PVD chambers that may be adapted to benefit from the present disclosure includePlus and SIPPVD processing chambers, both of which are commercially available from Applied Materials, Inc., of Santa Clara, Calif. Can be used forOther process chambers available from application materials companies and other manufacturers may also be adapted according to embodiments described herein.

The processing chamber 100 generally includes an upper sidewall 102, a lower sidewall 103, a ground adapter 104, and a lid assembly 111 that define a body 105, the body 105 enclosing an interior volume 106. The interior volume 106 includes a central portion having approximately a given diameter of a substrate to be processed and a peripheral portion surrounding the central portion. In addition, the inner volume 106 comprises an annular region above the substrate and proximate the target, wherein an inner diameter of the annular region is substantially equal to or greater than a diameter of the substrate such that a substantial portion of the plasma is disposed in a position above and radially outward of the substrate.

An adapter plate 107 may be disposed between the upper sidewall 102 and the lower sidewall 103. A substrate support 108 is disposed in the interior volume 106 of the processing chamber 100. The substrate support 108 is configured to support a substrate having a given diameter (e.g., 150mm, 200mm, 300mm, 450mm, or the like). A substrate transfer port 109 is formed in the lower sidewall 103 for transferring substrates into and out of the interior volume 106.

In some embodiments, the process chamber 100 is configured to deposit, for example, titanium, aluminum oxide, aluminum oxynitride, copper, tantalum nitride oxide, titanium nitride oxide, tungsten, or tungsten nitride on a substrate, such as the substrate 101. Non-limiting examples of suitable applications include seed layer deposition in vias, trenches, dual damascene structures, or similar structures.

A gas source 110 is coupled to the processing chamber 100 to supply a process gas into the interior volume 106. In some embodiments, the process gas may include an inert gas, a non-reactive gas, and a reactive gas, if desired. Examples of process gases that may be provided by the gas source 110 include, but are not limited to, argon (Ar), helium (He), neon (Ne), nitrogen (N)₂) Oxygen (O)₂) And water (H)₂O) steam, and the like.

A pumping device 112 is coupled to the process chamber 100 to communicate with the internal volume 106 to control the pressure of the internal volume 106. In some embodiments, the pressure level of the processing chamber 100 may be maintained at about 1 torr or less during deposition. In some embodiments, the pressure level of the processing chamber 100 may be maintained at about 500 mtorr or less during deposition. In some embodiments, the pressure level of the process chamber 100 may be maintained at about 1 mtorr to about 300 mtorr during deposition.

The ground adapter 104 may support a target, such as target 114. The target 114 is made of a material to be deposited on a substrate. In some embodiments, the target 114 may be made of titanium (Ti), tantalum (Ta), tungsten (W), cobalt (Co), nickel (Ni), copper (Cu), aluminum (Al), alloys thereof, combinations thereof, or the like. In some embodiments, the target 114 may be made of copper (Cu), titanium (Ti), tantalum (Ta), or aluminum (Al).

The target 114 may be coupled to a source assembly including a power source 117 for the target 114. In some embodiments, the power source 117 may be an RF power source, which may be coupled to the target 114 via a matching network. In some embodiments, the power supply 117 may alternatively be a DC power source, in which case the matching network 116 is omitted. In some embodiments, the power supply 117 may include a DC power source and an RF power source.

The magnetron 170 is above the target 114. The magnetron 170 may include a plurality of magnets 172, the plurality of magnets 172 being supported by a base plate 174 coupled to a shaft 176, the shaft 176 may be axially aligned with a central axis of the processing chamber 100 and the substrate 101. The magnet 172 generates a magnetic field within the process chamber 100 proximate the front of the target 114 to generate a plasma, so that a substantial flux of ions strikes the target 114, causing sputter emission of the target material. The magnet 172 may be rotated about an axis 176 to increase the uniformity of the magnetic field across the surface of the target 114. Examples of magnetrons include electromagnetic linear magnetrons, serpentine magnetrons, helical magnetrons, dual digital magnetrons, rectangularly helical magnetrons, dual motion magnetrons, and the like. The magnets 172 rotate about a central axis of the processing chamber 100 within an annular region extending between about the outer diameter of the substrate to about the outer diameter of the internal volume 106. In general, the magnet 172 may be rotated such that an innermost magnet position during rotation of the magnet 172 is disposed above or outside a diameter of a substrate to be processed (e.g., a distance from the axis of rotation to the innermost position of the magnet 172 is equal to or greater than the diameter of the substrate being processed).

The magnetron can have any suitable motion pattern in which the magnets of the magnetron rotate within an annular region approximately between the outer diameter of the substrate and the inner diameter of the processing space. In some embodiments, the magnetron 170 has a radius of rotation of a fixed magnet 172 about a central axis of the processing chamber 100. In some embodiments, the magnetron 170 is configured to have multiple or adjustable radii of rotation of the magnet 172 about the central axis of the processing chamber 100. For example, in some embodiments, the radius of rotation of the magnetron can be adjusted between about 5.5 inches and about 7 inches (e.g., for processing 300mm substrates). For example, in some embodiments, the magnetron has a dual motion in which the magnet 172 is rotated at a first radius (e.g., about 6.7 inches when processing 300mm substrates) for a first predetermined period of time and at a second radius (e.g., about 6.0 inches when processing 300mm substrates) for a second predetermined period of time. In some embodiments, the first predetermined period of time and the second predetermined period of time are substantially equal (e.g., the magnetron is rotated about half of the processing time at the first radius and rotated about half of the processing time at the second radius). In some embodiments, the magnetron may be rotated at multiple radii (i.e., more than exactly two radii), which may be set discretely for different periods of time, or continuously varied throughout the process. The inventors have found that when the process uses multi-radius rotation of the magnetron, the target lifetime and plasma stability are advantageously further improved.

The processing chamber 100 further includes an upper shield 113 and a lower shield 120. A collimator 118 is positioned in the interior volume 106 between the target 114 and the substrate support 108. In some embodiments, the collimator 118 has a central region 135 and a peripheral region 133, the central region 135 having a thickness T₁The peripheral region 133 has a thickness T₂Thickness T₂Less than thickness T₁. The central region 135 generally corresponds to a diameter of the substrate being processed (e.g., equal or substantially equal to the diameter of the substrate). Thus, the peripheral region 133 generally corresponds toAn annular region at a location radially outward of the substrate being processed (e.g., the inner diameter of the peripheral region 133 is substantially equal to or greater than the diameter of the substrate). Alternatively, the central region of the collimator 118 may have a diameter that is larger than the diameter of the substrate being processed. In some embodiments, the collimator 118 may have a uniform thickness across the entire collimator, without separate central and peripheral regions. The collimator 118 is coupled to the upper shield 113 using any fixing means. In some embodiments, the collimator 118 may be integrally formed with the upper shield 113. In some embodiments, the collimator 118 may be coupled to some other component within the processing chamber and facilitate positioning relative to the upper shield 113.

In some embodiments, the collimator 118 may be electrically biased to control the ion flux to the substrate and the neutral angular distribution at the substrate, as well as to increase the deposition rate due to increased DC bias. The electrical biasing of the collimator results in reduced ion loss to the collimator, advantageously providing a greater ion/neutral species ratio at the substrate. A collimator power supply 190 (shown in fig. 2) is coupled to the collimator 118 to facilitate biasing of the collimator 118.

In some embodiments, the collimator 118 may be electrically isolated from grounded chamber components (such as the grounded adapter 104). For example, as shown in FIG. 1, the collimator 118 is coupled to the upper shield 113, and the upper shield 113 is in turn coupled to the processing tool adapter 138. The process tool adapter 138 may be made of a suitable conductive material that is compatible with the processing conditions in the processing chamber 100. An insulating ring 156 and an insulating ring 157 are disposed on either side of the process tool adapter 138 to electrically isolate the process tool adapter 138 from the ground adapter 104. The insulating rings 156, 157 may be made of a suitable process compatible dielectric material.

In some embodiments, a first set of magnets 196 may be disposed adjacent the ground adapter 104 to assist in generating a magnetic field to direct ions dislodged from the target 114 through the peripheral region 133. The magnetic field created by the first set of magnets 196 may alternatively or in combination prevent ions from striking the sidewalls of the chamber (or the sidewalls of the upper shield 113) and direct ions vertically through the collimator 118. For example, the first set of magnets 196 is configured to form a magnetic field having substantially vertical magnetic field lines in the peripheral portion. The substantially vertical magnetic field lines advantageously guide ions through a peripheral portion of the interior volume and, when the collimator 118 is present, through a peripheral region 133 of the collimator 118.

In some embodiments, the second set of magnets 194 may be disposed in a position to create a magnetic field between the bottom of the collimator 118 and the substrate to direct metal ions dislodged from the target 114 and to more evenly distribute the ions across the substrate. For example, in some embodiments, a second set of magnets may be disposed between the adapter plate 107 and the upper sidewall 102. For example, the second set of magnets 194 is configured to form a magnetic field having magnetic field lines directed toward the center of the support surface. The magnetic field lines directed towards the center of the support surface advantageously redistribute ions from the peripheral portion of the inner volume to the central portion of the inner volume and over the substrate 101.

In some embodiments, the third set of magnets 154 may be disposed between the first set of magnets 196 and the second set of magnets 194 and substantially centered on or below the substrate-facing surface of the central region 135 of the collimator 118 to further direct the metal ions toward the center of the substrate 101. For example, the third set of magnets 154 is configured to generate a magnetic field having magnetic field lines directed inwardly and downwardly toward the center portion and toward the center of the support surface. The magnetic field lines directed towards the center of the support surface further advantageously redistribute ions from the peripheral portion of the inner volume to the central portion of the inner volume and over the substrate 101.

The number of magnets disposed around the processing chamber 100 may be selected to control plasma dissociation (dissociation), sputtering efficiency, and ion control. The first set of magnets 196, the second set of magnets 194, and the third set of magnets 154 may comprise any combination of electromagnets and/or permanent magnets, as necessary to direct metal ions along a desired trajectory from the target, through the collimator, and toward the center of the substrate support 108. The first set of magnets 196, the second set of magnets 194, and the third set of magnets 154 may be stationary or movable to adjust the position of one set of magnets in a direction parallel to the central axis of the chamber.

An RF power source 180 may be coupled to the processing chamber 100 through the substrate support 108 to provide bias power between the target 114 and the substrate support 108. In some embodiments, the RF power source 180 may have a frequency between about 400Hz and about 60MHz, such as about 13.56 MHz. In some embodiments, the third set of magnets 154 may be eliminated and bias power is used to attract the metal ions toward the center of the substrate 101.

In operation, the magnet 172 rotates to form a plasma 165 in the annular portion of the interior volume 106 to sputter the target 114. When collimator 118 is present, plasma 165 may form over a peripheral region 133 of the collimator to sputter target 114 over peripheral region 133. The radius of rotation of the magnet 172 is greater than the radius of the substrate 101 to ensure that there is little or no sputtered material above the substrate 101. Non-limiting examples of suitable magnetrons that can be modified according to the present disclosure to rotate at a suitable radius or range of radii include the magnetrons disclosed in U.S. patent No. 8,114,256 entitled "Control of the Arbitrary Scan Path of a Rotating Magnetron" issued to Chang et al on day 2, month 14, 2012 and U.S. patent No. 9,580,795 entitled "Sputter Source for Use in a Semiconductor processing Chamber" issued to Miller et al on day 2, month 28, 2017.

The first set of magnets 196 forms a magnetic field proximate the peripheral region 133 to attract sputtered material toward the peripheral region 133. In some embodiments, a substantial portion of the sputtered material (e.g., ionized sputtered material) is attracted toward the peripheral region by the first set of magnets.

The collimator 118 is positively biased such that the metal sputtering material is forced through the collimator 118. However, since plasma 165 and most, if not all, of the metal sputtered material is disposed at peripheral region 133, the metal sputtered material travels only through peripheral region 133. Furthermore, most, if not all, of the neutral sputtered material travelling towards the central region of the collimator will likely collide with and adhere to the collimator walls. In addition to the bias power applied to the substrate support 108, the second set of magnets 194 and the third set of magnets 154 (when present) redirect the trajectory of the sputtered metal ions toward the center of the substrate 101. Therefore, imprinting on the substrate due to the shape of the collimator 118 is avoided and more uniform deposition is achieved.

Since the directionality of the metallic neutral species cannot be changed, most, if not all, of the metallic neutral species advantageously do not deposit on the substrate. To ensure that the trajectory of the sputtered metal ions has sufficient space to change, the collimator 118 is disposed at a predetermined height h above the support surface 119 of the substrate support 108₁To (3). In some embodiments, the height h₁Between about 400mm to about 800mm, for example about 600mm (measured from the bottom of the collimator 118 to the support surface 119). Height h₁Is also selected to facilitate control of ions using a magnetic field below the collimator 118 to further improve deposition characteristics on the substrate 101. To be able to modulate the magnetic field above the collimator 118, the collimator 118 may be arranged at a predetermined height h below the target 114₂To (3). Height h₂May be between about 25mm to about 75mm, for example about 50 mm. The total target-to-substrate spacing (or target-to-support surface spacing) is about 600mm to about 800 mm.

The process tool adapter 138 includes one or more features to facilitate supporting a process tool, such as the collimator 118, within the internal volume 106. For example, as shown in FIG. 1, the process tool adapter 138 includes a mounting ring, or shelf 164 extending in a radially inward direction to support the upper shield 113. In some embodiments, the mounting ring or shelf 164 is a continuous ring around the inner diameter of the process tool adapter 138 to promote more uniform thermal contact with the upper shield 113 mounted to the process tool adapter 138.

In some embodiments, coolant channels 166 may be provided in the process tool adapter 138 to facilitate coolant flow through the process tool adapter 138 to remove heat generated during processing. For example, the coolant channel 166 may be coupled to the coolant source 153 to provide a suitable coolant, such as water. The coolant channels 166 advantageously remove heat from the processing tool (e.g., collimator 118) that is not readily transferred to other cooled chamber components, such as the ground adapter 104. For example, the insulating rings 156, 157 disposed between the process tool adapter 138 and the ground adapter 104 are typically made of a poor thermally conductive material. Accordingly, the insulating rings 156, 157 reduce the rate of heat transfer from the collimator 118 to the ground adapter 104, and the process tool adapter 138 advantageously maintains or increases the rate of cooling of the collimator 118. In addition to the coolant channels 166 provided in the process tool adapter 138, the ground adapter 104 may also include coolant channels to further facilitate removal of heat generated during processing.

A radially inwardly extending boss (ridge) (e.g., a mounting ring, or shelf 164) is provided to support the upper shield 113 within the central opening within the interior volume 106 of the processing chamber 100. In some embodiments, the shelf 164 is disposed proximate to the coolant channels 166 to facilitate maximizing heat transfer from the collimator 118 to the coolant flowing in the coolant channels 166 during use.

In some embodiments, the lower shield 120 may be provided adjacent the collimator 118 and inside the ground adapter 104 or the upper sidewall 102. The collimator 118 includes a plurality of apertures to direct the gas and/or material flux within the interior volume 106. Collimator 118 may be coupled to a collimator power supply via a process tool adapter 138.

The lower shield 120 may include a tubular body 121, the tubular body 121 having a radially outwardly extending flange 122 disposed in an upper surface of the tubular body 121. The flange 122 provides a mating interface with the upper surface of the upper sidewall 102. In some embodiments, the tubular body 121 of the lower shield 120 may include a shoulder region 123, the shoulder region 123 having an inner diameter that is less than the inner diameter of the remainder of the tubular body 121. In some embodiments, the inner surface of tubular body 121 transitions radially inward along tapered surface 124 to the inner surface of shoulder region 123. A shield ring 126 may be disposed in the process chamber 100 adjacent to the lower shield 120 and intermediate the lower shield 120 and the adapter plate 107. The shield ring 126 may be at least partially disposed in a groove 128, the groove 128 being formed by opposing sides of the shoulder region 123 of the lower shield 120 and the inner sidewall of the adapter plate 107.

In some embodiments, the shield ring 126 may include an axially projecting annular sidewall 127, the annular sidewall 127 having an inner diameter greater than an outer diameter of the shoulder region 123 of the lower shield 120. A radial flange 130 extends from the annular sidewall 127. The radial flange 130 may be formed at an angle greater than about 90 degrees (90 °) relative to an inner diameter surface of the annular sidewall 127 of the shield ring 126. The radial flange 130 includes a protrusion 132 formed on a lower surface of the radial flange 130. The protrusion 132 may be a circular ridge extending from the surface of the radial flange 130 in an orientation substantially parallel to the inner diameter surface of the annular sidewall 127 of the shield ring 126. The protrusions 132 are generally adapted to mate with recesses 134 formed in an edge ring 136, the edge ring 136 being disposed on the substrate support. The recess 134 may be a circular groove formed in an edge ring 136. The engagement of the protrusions 132 and the recesses 134 centers the shield ring 126 relative to the longitudinal axis of the substrate support 108. The substrate 101 (shown supported on the lift pins 140) is centered with respect to the longitudinal axis of the substrate support 108 through coordinated positioning calibration between the substrate support 108 and the robot blade (not shown). Thus, the substrate 101 may be centered within the processing chamber 100 and the shield ring 126 may be centered radially around the substrate 101 during processing.

In operation, a robot blade (not shown) having the substrate 101 disposed thereon extends through the substrate transfer port 109. The substrate support 108 may be lowered to allow the substrate 101 to be transferred to lift pins 140 extending from the substrate support 108. The elevation of the substrate support 108 and/or the lift pins 140 may be controlled by a drive 142 coupled to the substrate support 108. The substrate 101 may be lowered onto the substrate receiving surface 144 of the substrate support. With the substrate 101 positioned on the substrate receiving surface 144 of the substrate support 108, sputter deposition may be performed on the substrate 101. The edge ring 136 may be electrically isolated from the substrate 101 during processing. Accordingly, the substrate receiving surface 144 may include a height greater than a height of a portion of the edge ring 136 adjacent the substrate 101 such that the substrate 101 is prevented from contacting the edge ring 136. During sputter deposition, the temperature of the substrate 101 may be controlled by utilizing a thermal control channel 146 disposed in the substrate support 108.

After sputter deposition, the substrate 101 may be raised to a position spaced apart from the substrate support 108 using the lift pins 140. The raised position may be proximate to one or both of the shield ring 126 and the reflector ring 148 adjacent to the adapter plate 107. The adapter plate 107 includes one or more lamps 150, the one or more lamps 150 coupled to the adapter plate 107 at a location intermediate a lower surface of the reflector ring 148 and a concave surface 152 of the adapter plate 107. The lamp 150 provides optical and/or radiant energy at visible or near visible wavelengths, such as the Infrared (IR) and/or Ultraviolet (UV) spectrum. Energy from the lamps 150 is focused radially inward toward the backside (i.e., lower surface) of the substrate 101 to heat the substrate 101 and the material deposited thereon. Reflective surfaces on chamber components surrounding the substrate 101 serve to focus energy to the backside of the substrate 101 and to keep energy away from other chamber components where it will be lost and/or not utilized. The adapter plate 107 may be coupled to a coolant source 153 to control the temperature of the adapter plate 107 during heating.

After controlling the substrate 101 to the predetermined temperature, the substrate 101 is lowered to a position on the substrate receiving surface 144 of the substrate support 108. The substrate 101 may be rapidly cooled via conduction using the thermal control channels 146 in the substrate support 108. The temperature of the substrate 101 may decrease from the first temperature to the second temperature in a matter of seconds to about one minute. The substrate 101 may be removed from the processing chamber 100 through the substrate transfer port 109 to be further processed. The substrate 101 may be maintained within a predetermined temperature range, such as less than 250 degrees celsius.

A controller 198 is coupled to the process chamber 100. The controller 198 includes a Central Processing Unit (CPU)160, memory 158, and support circuits 162. The controller 198 is used to control the process sequence, regulate the gas flow from the gas source 110 into the process chamber 100, and control the ion bombardment of the target 114. The CPU 160 may be any form of a general purpose computer processor that can be used in an industrial environment. The software routines may be stored in a memory 158, such as random access memory, read only memory, floppy or hard disk drive, or other form of digital storage. The support circuits 162 are conventionally coupled to the CPU 160 and may include cache, clock circuits, input/output subsystems, power supplies, or the like. When the software program is executed by the CPU 160, the CPU is converted into a special purpose computer (controller) 198, and the special purpose computer (controller) 198 controls the process chamber 100 such that processes (including the plasma excitation processes disclosed below) are performed in accordance with embodiments of the present disclosure. The software routines may also be stored and/or executed by a second controller (not shown) located at a remote location from the process chamber 100.

During processing, material is sputtered from the target 114 and deposited on the surface of the substrate 101. The target 114 and the substrate support 108 are biased relative to each other by a power supply 117 or an RF power source 180 to maintain a plasma formed from the process gas supplied by the gas source 110. The DC pulsed bias power applied to the collimator 118 also helps to control the ratio of ions and neutral species passing through the collimator 118, thereby advantageously enhancing trench sidewall and underfill capability. Ions from the plasma are accelerated toward the target 114 and impact the target 114 causing target material to be dislodged from the target 114. The dislodged target material and process gas form a layer having a desired composition on the substrate 101.

Fig. 2 depicts a top view of an illustrative collimator 118 coupled to a collimator power supply 190, the collimator power supply 190 may be disposed in the process chamber 100 of fig. 1. In some embodiments, the collimator 118 has a generally honeycomb-like structure with hexagonal walls 226 separating hexagonal apertures 244 in a dense arrangement. However, other geometric configurations may also be used. The aspect ratio of the hexagonal aperture 244 may be defined as the depth of the aperture 244 (equal to the length of the collimator) divided by the width 246 of the aperture 244. In some embodiments, the thickness of the wall 226 is about 0.06 inches to about 0.18 inches. In some embodiments, the wall 226 has a thickness of about 0.12 inches to about 0.15 inches. In some embodiments, the aspect ratio of the hexagonal apertures 244 may be between about 1: between 1 and about 1:5, and may be between about 3:5 and about 3:6 in the central region 135. In some embodiments, the collimator 118 is composed of a material selected from the group consisting of aluminum, copper, and stainless steel.

The honeycomb structure of the collimator 118 may be used as an integrated flux optimizer 210 to optimize the flow path, ion fraction, and ion trajectory behavior of ions through the collimator 118. In some embodiments, the hexagonal walls 226 adjacent to the shield portion 202 have a chamfer 250 and a radius. The shielding portion 202 of the collimator 118 may facilitate installation of the collimator 118 into the processing chamber 100.

In some embodiments, the collimator 118 may be machined from a single piece of aluminum. The collimator 118 may optionally be coated or anodized. Alternatively, the collimator 118 may be made of other materials compatible with the processing environment, and may also be constructed of one or more sections. Alternatively, the shield portion 202 and the integrated flux optimizer 210 are formed as separate pieces and coupled together using suitable connection means (such as welding).

Fig. 3 illustrates a method 300 for processing a substrate. The method 300 may be performed in an apparatus similar to that discussed above and described in connection with the processing chamber 100 of fig. 1. The method generally begins at 302, where a plasma is formed within an annular region of the processing chamber 100. The annular region has an inner diameter substantially equal to or greater than the inner diameter of the substrate 101. For example, a plasma may be formed within an annular region of the processing chamber above and proximate the target to sputter material from the target, wherein an inner diameter of the annular region is substantially equal to or greater than a diameter of the substrate such that a substantial portion of the plasma is disposed in a location above and radially outward of the substrate.

At 304, material sputtered from the target is directed toward the substrate. Any of the techniques disclosed herein may be used, alone or in combination, to direct materials (e.g., ions) toward a substrate. For example, in some implementations, a collimator (e.g., collimator 118) may be provided to filter out materials, such as neutral particles, that do not travel substantially vertically toward the substrate 101 and thus strike and adhere to the sidewalls of the channels of the collimator 118. Additionally, the collimator 118 may be electrically biased with a voltage having the same polarity as the polarity of ions formed in the plasma to reduce the impact of ions on the sidewalls of the collimator's channels and straighten the trajectories of the ions to be more vertical, as indicated at 306. For example, a positive voltage may be provided when positively charged ions (such as copper ions) are present. Alternatively or in combination, a first set of magnets may be used to generate a first magnetic field to form a magnetic field having substantially vertical magnetic field lines in the annular region (and through (when present) the collimator 118), as indicated at 308. Alternatively, the fire, in combination with the foregoing, may use a second set of magnets to generate a second magnetic field to form a magnetic field having magnetic field lines directed toward the center of the substrate, as indicated at 310. Alternatively or in combination with the foregoing, a third set of magnets may be used to generate a third magnetic field to form a magnetic field having magnetic field lines directed inwardly and downwardly toward the center of the substrate. Alternatively or in combination with the foregoing, the substrate support may be electrically biased to attract ions toward the substrate.

Next, at 312, material sputtered from the target is deposited on the substrate. Upon deposition to a desired thickness, the method 300 generally ends and further processing of the substrate may be performed.

For example, in some embodiments of the method 300, the plasma 165 is formed over the peripheral region 133 of the collimator 118 using the magnet 172 and material is sputtered from the target 114 over the peripheral region 133. A first set of magnets 196 is used to generate a first magnetic field near the peripheral region 133 to attract sputtered material toward the peripheral region 133. The collimator 118 is biased with a positive voltage to attract sputtered material through the peripheral region 133 of the collimator 118. A second magnetic field is generated below the collimator 118 to attract material through the collimator 118 and redirect ions of the sputtered material toward the center of the substrate support. The second magnetic field may be generated by one or more of the second set of magnets 194, one or more bias powers applied to the substrate support 108. Optionally, a third set of magnets 154 may be used to generate a third magnetic field to form a magnetic field having magnetic field lines directed inwardly and downwardly toward the center of the substrate 101. In addition, the substrate support 108 may be electrically biased to attract ions towards the substrate 101.

Accordingly, embodiments of methods and apparatus for improving substrate deposition uniformity have been disclosed herein. The inventors have observed that the method and apparatus of the present invention substantially eliminate imprint from conventional deposition processes using collimators, and produce a more uniform deposition on the substrate to be processed.

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.