Worktable surface modification and high performance pad conditioning for improved cmp performance

Abstract

Embodiments herein generally relate to chemical mechanical polishing (CMP) systems and methods for reducing non-uniform material removal at or near a peripheral edge of a substrate when compared to a region radially inward from the substrate. In one embodiment, a polishing system includes a substrate carrier including an annular retainer for enclosing a substrate to be processed during a polishing process, and a polishing table. The polishing table includes a cylindrical metal body having a pad mounting surface. The pad mounting surface includes a plurality of polishing zones including a first zone having a circular shape or an annular shape, a second zone circumscribing the first zone, and a third zone circumscribing the second zone. A surface of the second zone is recessed from surfaces of the first and third zones adjacent the second zone, and a width of the second zone is less than an outer diameter of the annular retainer.

Description

Background Technology Technical Field

[0001] The embodiments described herein generally relate to semiconductor device manufacturing, and more specifically to chemical mechanical polishing (CMP) systems and associated substrate processing methods used in semiconductor device manufacturing.

[0002] Description of related technologies

[0003] Chemical mechanical polishing (CMP) is commonly used in the fabrication of high-density integrated circuits to planarize or polish material layers deposited on a substrate. A common application of CMP in semiconductor device manufacturing is the planarization of bulk films, such as pre-metal dielectric (PMD) or interlayer dielectric (ILD) polishing, where underlying two-dimensional or three-dimensional features form grooves and protrusions in the surface of the material to be planarized. Other common applications include shallow trench isolation (STI) and interlayer metal interconnect formation, where CMP processes are used to remove vias, contacts, or trench fill material (overlay) from exposed surfaces (fields) of material layers with STI or metal interconnect features disposed therein.

[0004] In a typical CMP process, a polishing pad is mounted on a rotating polishing stage. In the presence of a polishing slurry, the material surface of the substrate is pressed against the polishing pad. Typically, the polishing slurry is an aqueous solution of one or more chemically active components and abrasive particles suspended in an aqueous solution, such as a CMP slurry. A substrate carrier is used to press the material surface of the substrate against the polishing pad. A typical substrate carrier includes a membrane, capsule, or backplate disposed against the back surface of the substrate and an annular retainer for attaching the substrate. The membrane, capsule, or backplate applies downward pressure to the substrate as the substrate carrier rotates about its axis. The retainer surrounds the substrate as it is pressed against the polishing pad and prevents the substrate from slipping off the substrate carrier. Material is removed from the surface of the substrate in contact with the polishing pad through a combination of chemical and mechanical activity provided by the polishing slurry, the relative movement of the substrate and the polishing pad, and the downward pressure applied to the substrate against the polishing pad.

[0005] Generally, CMP process performance is characterized by the material removal rate from the substrate surface and the uniformity of the material removal rate on the substrate surface (removal rate uniformity). In dielectric film planarization processes, non-uniform material removal rates on the substrate surface can lead to poor planarity and / or undesirable thickness variations in the remaining dielectric material after CMP. In metal interconnect CMP applications, metal loss due to poor local planarization and / or non-uniform material removal rates can cause undesirable variations in the effective resistance of metal features, thereby affecting device performance and reliability. Therefore, non-uniform material removal rates on the substrate surface can adversely affect device performance and / or cause device failure, which can suppress the yield of usable devices formed on the substrate.

[0006] Typically, non-uniform material removal rates are more pronounced in surface regions near the peripheral edges of the substrate (e.g., within 6 mm of the peripheral edge of a 300 mm diameter substrate) compared to the average material removal rate calculated for locations radially inward from the peripheral edge. Non-uniform material removal rates at the substrate edges are believed to be caused at least in part by a combination of the polishing pad "bounce" effect and non-uniform fluid distribution across the substrate between the leading and trailing edges of the polishing interface. The polishing pad bounce effect is believed to be caused at least in part by a higher downward pressure applied to the polishing pad for pressing the retainer against it than the downward pressure applied to push the substrate material surface against the polishing pad, resulting in higher contact pressure at the interface between the polishing pad and the substrate edge. Non-uniform fluid distribution is also believed to be caused at least in part by the interaction between the retainer and the polishing pad to create a non-uniform fluid thickness between the leading and trailing edges of the polishing interface. Previous and ongoing solutions to the aforementioned problems have focused on more complex substrate carrier and retainer designs. Unfortunately, such substrate carrier and / or retainer designs can be undesirably expensive and complex.

[0007] Therefore, a solution to the above problems is needed in this field. Summary of the Invention

[0008] The embodiments described herein generally relate to chemical mechanical polishing (CMP) systems and methods for reducing the rate of non-uniform material removal at or near the peripheral edge of a substrate compared to a region radially inward from the substrate.

[0009] In one embodiment, a polishing system includes: a substrate carrier including an annular retainer for surrounding a substrate to be processed during a polishing process; and a polishing stage. The polishing stage includes a cylindrical metal body having a pad mounting surface. The pad mounting surface includes a plurality of polishing zones, including a first zone having a circular or annular shape, a second zone surrounding the first zone, and a third zone surrounding the second zone. Here, at least a portion of the pad mounting surface in the first and third zones defines a plane orthogonal to the axis of rotation of the polishing stage, the pad mounting surface in the second zone is recessed from the plane, and the width of the second zone is less than the outer diameter of the annular retainer.

[0010] In another embodiment, a method of polishing a substrate includes pressing the substrate against the surface of a polishing pad, wherein the polishing pad is disposed on a pad mounting surface of a polishing stage. The pad mounting surface includes a plurality of polishing zones, including a first zone having a circular or annular shape, a second zone surrounding the first zone, and a third zone surrounding the second zone. Here, at least a portion of the pad mounting surface in the first and third zones defines a plane orthogonal to the axis of rotation of the polishing stage, and the pad mounting surface in the second zone is recessed from the plane.

[0011] In another embodiment, a polishing table includes a cylindrical metal body having a pad mounting surface. The pad mounting surface includes a plurality of polishing zones, including a first zone having a circular or annular shape, a second zone surrounding the first zone, and a third zone surrounding the second zone. Here, at least a portion of the pad mounting surfaces of the first and third zones defines a plane orthogonal to the axis of rotation of the polishing table, the pad mounting surface in the second zone is recessed from the plane, and the width of the second zone is less than the outer diameter of the annular retainer. Attached Figure Description

[0012] To gain a more detailed understanding of the features described above in this disclosure, reference can be made to the embodiments to obtain a more specific description of the disclosure briefly outlined above, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of this disclosure and should therefore not be construed as limiting its scope, as other equivalent embodiments are permissible.

[0013] Figure 1A The non-uniform material removal rate across the substrate radius is schematically shown.

[0014] Figure 1B This is a schematic close-up cross-sectional view of a portion of the polished interface.

[0015] Figure 2A-2CA polishing system formed according to the embodiments described herein is illustrated schematically.

[0016] Figure 3 It is according to one embodiment that can be used as an alternative Figure 2A-2C A schematic cross-sectional view of the polishing table described.

[0017] Figure 4 This is a diagram illustrating a method for polishing a substrate according to one embodiment.

[0018] To facilitate understanding, the same reference numerals have been used as much as possible to identify common elements in the figures. It is contemplated that elements disclosed in one embodiment may be advantageously used in other embodiments without specific description. Detailed Implementation

[0019] Embodiments of this disclosure generally relate to chemical mechanical polishing (CMP) systems, and more specifically, to polishing stages and methods for reducing non-uniform material removal rates at or near the peripheral edges of a substrate when compared to regions radially inward from the substrate. Typically, depending on the type of CMP process, the material removal rate near the peripheral edges of the substrate may be less than or greater than the average material removal rate at locations radially inward from that edge. Non-uniform removal rates obtained at the substrate edges are typically characterized as “slow edge” or “fast edge” material removal rate distributions, respectively. Slow edge and fast edge material removal rate distributions are believed to be caused at least in part by a combination of the polishing pad “bounce” effect at the substrate edges and the uneven distribution of polishing slurry at the material surface of the substrate and the polishing interface of the polishing pad. Figure 1B An example of a fast edge material removal rate distribution 50 is schematically shown, wherein the difference between a relatively faster material removal rate at a first radial location near the substrate edge and a slower material removal rate at a location radially inward from the substrate edge is shown as ΔRR.

[0020] An example of the pad rebound effect is illustrated in Figure 1A middle, Figure 1A A cross-sectional view of the polishing interface 10 between the polishing pad 12 and the substrate 13 resting thereon is shown. Here, a substrate carrier 16, including a flexible film 24 and an annular retaining ring 26, is used to push the substrate 13 against the polishing pad 12. The flexible film 24 applies downward pressure to the substrate 13, while the substrate carrier 16, and thus the substrate 13 and the polishing pad 12, rotate about their respective axes to provide relative movement between them. The retaining ring 26 surrounds the substrate 13 and serves to receive the substrate 13 and position the substrate 13 below the flexible film 24 during polishing, i.e., to prevent the substrate 13 from slipping off the substrate carrier 16.

[0021] Generally, in order to accommodate the substrate 13 at the desired polishing interface 10, a downward pressure is applied to the retaining ring 26, which is greater than and independent of the downward pressure applied to the substrate 13. Uneven pressure distribution between the retaining ring 26 and the peripheral edge of the substrate 13 near the retaining ring 26 causes the polishing pad 12 to deform or spring back at the outer and inner edges of the retaining ring 26 as the polishing pad 12 moves below the retaining ring 26. This pad springback effect 15 undesirably creates uneven contact pressure distribution at the substrate edges and radially inward points between the substrate 13 and the polishing pad 12.

[0022] In addition to the pad rebound effect, CMP material rate uniformity is also determined by the complex frictional interactions between the surface and the fluid at the polishing interface, as well as their relative motion. For example, without being bound by theory, it is generally assumed that the polishing fluid layer at the polishing interface may be relatively thin at the leading edge of the substrate (because the polishing pad rotates beneath it) and gradually thickens towards the trailing edge. This non-uniform polishing fluid thickness between the leading and trailing edges of the substrate can further lead to different (e.g., non-uniform) material removal rates at the substrate edges compared to points radially inward from the substrate edge.

[0023] Therefore, embodiments herein provide polishing systems and methods designed to significantly reduce and / or eliminate pad rebound effects at the front and rear polished edges of a substrate and significantly improve the inherently non-uniform material removal rate distribution associated therewith. Advantageously, it is further believed that the polishing systems and methods described herein reduce the variation in polishing slurry thickness on the substrate surface to improve the non-uniform material removal rate distribution that may result therefrom.

[0024] Figure 2A This is a schematic top view of a polishing system 200 configured to practice the methods described herein, according to one embodiment. Figure 2B This is a schematic cross-sectional view of the polishing system 200. Figure 2C This is a schematic side view of the pad adjuster assembly 208 and a cross-sectional view of a part of the polishing system 200. Figure 2A-2C Some components of the polishing system 200 shown in any of the figures are not shown in the remaining figures in order to reduce visual clutter.

[0025] Here, the polishing system 200 includes a polishing stage 202, a substrate carrier 204, a fluid delivery arm 206, a pad adjuster assembly 208, and a system controller 210. The polishing stage 202 is characterized by a cylindrical stage body 214 and a low-adhesion material layer 216 disposed on the surface of the stage body 214 to provide a polishing pad mounting surface 218. The stage body 214 is typically formed of a suitable, rigid, lightweight, and polishing fluid-resistant material, such as aluminum, aluminum alloys (e.g., 6061 aluminum), or stainless steel. The low-adhesion material layer 216 typically comprises a polymeric material formed from one or more fluoropolymer precursors or melt-processable fluoropolymers. The low-adhesion material layer 216 desiccably reduces the force required to remove the polishing pad 212 from the polishing pad mounting surface 218 once the polishing pad 212 has reached the end of its service life and further protects the metal of the stage body 214 from unwanted polishing fluid corrosion.

[0026] Here, the pad mounting surface 218 includes a plurality of concentric regions 220a to 220c formed around the worktable axis A. The plurality of concentric regions 220a to 220c include a circular (when viewed from above) or annular first region 220a, an annular second region 220b external to the first region 220a, and an annular third region 220c arranged radially outward from and external to the second region 220b.

[0027] Here, the pad mounting surface 218 in the second region 220b is recessed from the plane P by a distance Z. The plane P is defined by the pad mounting surfaces 218 in the first region 220a and the third region 220c, and in some embodiments, and as... Figure 2B As shown, the pad mounting surfaces 218 in the first region 220a and the third region 220c are substantially coplanar with each other. In some embodiments, for example, where the pad mounting surfaces 218 in the first region 220a and the third region 220c are not coplanar with each other, the plane P may be defined by an object having a planar surface that is placed on and in contact with the first region 220a and the third region 220c to extend across the recess in the second region 220b. For example, in Figure 2B In this configuration, plane P is defined by the surface of a retainer of a substrate carrier positioned on the worktable to span the width W of the second region 220b and extending on either side therebetween a distance between approximately 25 mm and approximately 100 mm, such as between approximately 25 mm and approximately 50 mm or between approximately 50 mm and approximately 100 mm. In some embodiments, plane P is orthogonal to the axis of rotation A of the polishing worktable 202.

[0028] In some embodiments, the pad mounting surface 218 in the second region 220b is recessed from the plane P by a distance Z of about 20 μm or greater, about 30 μm or greater, about 40 μm or greater, about 50 μm or greater, or about 60 μm or greater. In some embodiments, the distance Z is between about 20 μm and about 500 μm, such as between about 20 μm and about 400 μm, between about 20 μm and about 300 μm, between about 20 μm and about 250 μm, or between about 20 μm and about 200 μm, such as between about 20 μm and about 150 μm. In some embodiments, the distance Z is between about 50 μm and about 500 μm, such as between about 50 μm and about 400 μm, between about 50 μm and about 400 μm, between about 50 μm and about 300 μm, between about 50 μm and about 250 μm, or between about 50 μm and about 150 μm.

[0029] exist Figure 2B In this embodiment, the pad mounting surface 218 in the second region 220b is substantially planar and parallel to the plane formed by the surfaces of the first region 220a and the third region 220c. Therefore, the distance Z(1) is substantially constant over the width W of the recessed pad mounting surface 218 in the second region 220b. In other embodiments, the recessed surface in the second region 220b is not parallel to the plane formed by the pad mounting surfaces of the first region 220a and the third region 220c and / or is substantially uneven over the width W of the recessed surface. For example, in some embodiments, the pad mounting surface 218 in the second region 220b may have a generally convex shape when viewed in cross-section, and the distance Z(1) is the average of a plurality of distances measured over the width W from the plane P to the surface in the second region 220b.

[0030] In some embodiments, the width W of the recessed pad mounting surface 218 in the second region 220b is smaller than the diameter of the substrate 213 to be polished, for example, about 0.9 × (times) or less, about 0.8 × or less, about 0.75 × or less, about 0.7 × or less, about 0.65 × or less, about 0.6 × or less, about 0.55 or less, or about 0.5 × or less of the diameter D of the substrate to be polished. For example, for a polishing stage 202 sized and configured to process substrates with a diameter of 300 mm, the width W of the recessed pad mounting surface 218 in the second region 220b may be about 270 mm or less. In one embodiment, the polishing stage 202 sized to polish substrates with a diameter of 300 mm has a radius R (1) between about 350 mm and about 400 mm, such as about 380 mm. In one embodiment, the inner radius R(2) of the second region 220b is greater than approximately 0.15 × the radius R(1), the outer radius R(3) of the second region 220b is less than approximately 0.85 × the radius R(1), and the width W of the second region 220b is at least approximately 0.15 × the radius R(1). Appropriate scaling can be used for polishing stages configured to process substrates of different sizes, for example, polishing stages configured to process substrates with diameters of 450 mm, 200 mm, or 150 mm.

[0031] In some embodiments, the pad mounting surface 218 in the third region 220c is not coplanar with the pad mounting surface 218 in the second region 220b. For example, in some embodiments, the pad mounting surface 218 in the third region 220c is above or below (in the direction of gravity) the plane formed by the pad mounting surface 218 in the first region 220a. In some embodiments, the pad mounting surface 218 in the third region 220c is inclined, such as... Figure 3 As shown and described.

[0032] In some embodiments, the position and size of the annular second region 220b are set such that during polishing, at least a portion of the substrate 213 is disposed over and across the recessed pad mounting surface 218 of the second region 220b, and at least a portion of the substrate 213 is disposed over the pad mounting surfaces 218 of the first region 220a and the third region 220c adjacent to the second region 220b. Therefore, during substrate processing, the distal region of the rotating substrate carrier 204 and the substrate 213 disposed therein are simultaneously disposed over the pad mounting surfaces 218 in the first region 220a and the third region 220c. Meanwhile, the recessed pad mounting surface 218 of the second region 220b rotates about the stage axis A to be positioned at the leading edge 222a and the trailing edge 222b of the rotating substrate carrier 204. Figure 2A It passes below the substrate 213 to be polished, which is located in the substrate carrier 204.

[0033] Typically, the polishing pad 212 is formed of one or more layers of polymer material and is fixed to pad mounting surfaces 218a to 218c using a pressure-sensitive adhesive. The polymer material used to form the polishing pad 212 can be relatively compliant or rigid, and has channels or grooves formed in its polishing surface to allow the polishing pad 212 to conform to the recessed pad mounting surface 218 in the second region 220b and the pad mounting surfaces 218 of the first region 220a and the third region 220c adjacent to the second region 220b. Thus, the polishing surface of the polishing pad 212 in each of the regions 220a to 220c has substantially the same shape and relative dimensions as described above for the pad mounting surface 218 of the worktable 202.

[0034] Here, the rotating substrate carrier 204 is used to apply downward pressure to the substrate 213 as the polishing pad 212 rotates about the stage axis A, pushing the material surface of the substrate 213 against the polishing pad 212. As shown, the substrate carrier 204 is characterized by a flexible membrane 224 and an annular retaining ring 226. During substrate polishing, the flexible membrane 224 applies downward pressure to the inactive surface (back surface) of the substrate 213 disposed below it. The retaining ring 226 surrounds the substrate 213 to prevent the substrate 213 from slipping off the substrate carrier 204 as the polishing pad 212 moves below the substrate 213. Typically, the substrate carrier 204 is configured to apply downward pressure to the retaining ring 226, which is independent of the downward pressure applied to the substrate 213. In some embodiments, the substrate carrier 204 oscillates in the radial direction of the polishing stage to partially reduce uneven wear of the polishing pad 212 disposed below it.

[0035] Typically, substrate 213 is pressed against polishing pad 212 in the presence of one or more polishing slurries delivered by fluid delivery arm 206. Typical polishing slurries comprise slurries formed from aqueous solutions in which abrasive particles are suspended. Generally, the polishing slurry contains one or more chemically active ingredients that modify the material surface of substrate 213, thereby enabling chemical mechanical polishing.

[0036] Pad Adjuster Assembly 208 ( Figure 2CThis assembly is used to adjust the polishing pad 212 by pushing the adjustment disk 228 against the surface of the polishing pad 212 before, after, or during polishing of the substrate 213. Here, the pad adjuster assembly 208 includes an adjustment disk 228, a first actuator 230 for rotating the adjustment disk 228 about an axis C, an adjuster arm 232 coupled to a second actuator 234, a rotational position sensor 235, a third actuator 236, and a displacement sensor 238. The second actuator 234 is used to oscillate the adjuster arm 232 about an axis D, thereby causing the adjustment disk 228 to sweep back and forth between the inner and outer radii of the polishing pad 212. The position sensor 235 is coupled to the second actuator 234 and is used to determine the angular position of the adjuster arm 232, which in turn can be used to determine the radial position of the adjustment disk 228 on the polishing pad 212 as the adjustment disk sweeps across it. The third actuator 236 is used to apply downward pressure to the adjusting disk 228 when the adjusting disk 228 is pushed against the polishing pad 212. Here, the third actuator 236 is coupled to the end of the arm 232 at a position close to the second actuator 234 and away from the adjusting disk 228.

[0037] Typically, the adjusting disk 228 is coupled to the first actuator 230 using a universal joint, which allows the adjusting disk 228 to maintain parallelism with the surface of the polishing pad 212 when the adjusting disk 228 is pressed against the surface of the polishing pad 212. Here, the adjusting disk 228 includes a fixed abrasive adjusting surface, such as diamond embedded in a metal alloy, and is used to grind and restore the surface of the polishing pad 212 and remove polishing byproducts or other debris from the surface of the polishing pad 212. Typically, the adjusting disk 228 has a diameter between about 80 mm and about 130 mm, such as between about 90 mm and about 120 mm, or for example about 108 mm (4.25 inches). In some embodiments, the diameter of the adjusting disk 228 is smaller than the width W of the second region 220b, such that the adjusting disk 228 can maintain surface contact with the polishing pad 212 during its adjustment in the second region 220b.

[0038] Here, displacement sensor 238 is an inductive sensor that measures eddy currents to determine the distance Z(2) between the end of sensor 238 and the metal surface of the worktable body 214 disposed below sensor 238. Displacement sensor 238 is used in conjunction with position sensor 235 to determine the recessed distance Z(3) between the surface of polishing pad 212 in second region 220b and the surface of polishing pad 212 in first region 220a and third region 220c adjacent to second region 220b.

[0039] In some embodiments, the pad adjuster assembly 208 is used to maintain the recessed relationship of the surface of the polishing pad 212 in the second zone 220b relative to the surfaces of the polishing pad 212 in the first zone 220a and the third zone 220c adjacent to the second zone 220b. In those embodiments, the system controller 210 can be used to change the dwell time of the adjusting disk 228 in the second zone 220b and / or the downward pressure on the adjusting disk 228. As used herein, dwell time refers to the average duration spent by the adjusting disk 228 at a radial position as the stage 202 rotates to move the polishing pad 212 below the stage 202, while the adjusting disk 228 sweeps from the inner radius to the outer radius of the polishing pad 212. For example, per cm in the second zone 220b 2 The adjustment residence time for the surface area of ​​the polishing pad can be relative to one or both of the first zone 220a and / or the third zone 220c adjacent to the second zone 220b, per cm. 2 Adjusting the surface area of ​​the polishing pad by increasing or decreasing the dwell time.

[0040] Here, the operation of the polishing system 200 (including the operation of the pad adjustment assembly 208) is controlled by the system controller 210. Figure 2A The system controller 210 includes a programmable central processing unit (CPU 240) that operates in conjunction with memory 242 (e.g., non-volatile memory) and support circuitry 244. For example, in some embodiments, the CPU 240 is one of any form of general-purpose computer processor used in an industrial environment, such as a programmable logic controller (PLC), for controlling various polishing system components and subprocessors. The memory 242 coupled to the CPU 240 is non-transitory and is typically one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), floppy disk drives, hard disks, or any other form of digital storage, local or remote. The support circuitry 244 is conventionally coupled to the CPU 240 and includes caches, clock circuitry, input / output subsystems, power supplies, and combinations thereof coupled to various components of the polishing system 200 to facilitate control of the substrate polishing process.

[0041] In this document, memory 242 is in the form of a computer-readable storage medium containing instructions (e.g., non-volatile memory) that, when executed by CPU 240, facilitate the operation of polishing system 200. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media that permanently stores information thereon (e.g., read-only memory devices within a computer, such as CD-ROM discs readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory); and (ii) writable storage media that store changeable information thereon (e.g., floppy disks or any type of solid-state random access semiconductor memory within a disk drive or hard disk drive). The instructions in memory 242 are in the form of a program product, such as a program that implements the methods of this disclosure (e.g., middleware applications, equipment software applications, etc.). In some embodiments, this disclosure may be implemented as a program product stored on a non-transitory computer-readable storage medium for use with a computer system. Therefore, the program(s) of the program product define the functionality of embodiments (including the methods described herein).

[0042] Figure 3 It can be used as a substitute Figure 2A-2B A schematic cross-sectional view of a portion of the polishing table 302 of the polishing table 202. Here, the table 302 has a pad mounting surface 318, which includes a plurality of concentric regions 320a to 320c formed around the table axis A. The plurality of concentric regions 320a to 320c include a circular (when viewed from above) or annular first region 320a, an annular second region 320b surrounding the first region 320a, and an annular third region 320c arranged radially outward from and surrounding the second region 320b. The table 302 may include any or a combination of the features of the table 202 described above.

[0043] Here, the pad mounting surface 318 in the third region 320c slopes upward from its intersection with the pad mounting surface 318 in the second region 320b to a position on or near the circumferential edge of the stage 302. For example, for a stage body 314 sized for a substrate with a diameter of 300 mm, the annular third region 320b may have an inner radius between about 250 mm and about 355 mm, such as between about 280 mm and about 330 mm. Typically, in those embodiments, the pad mounting surface 318 in the third region 320c is recessed from the plane P by an average distance Z (average), which is about 2 / 3 × or less, such as about 1 / 2 × or less, of the groove Z(1) of the pad mounting surface in the second region 320b. Here, the plane P is defined by at least a portion of the pad mounting surfaces of the first and third regions and is orthogonal to the axis of rotation A.

[0044] Figure 4 This is a diagram illustrating a method 400 for polishing a substrate according to one embodiment, which can be used... Figure 2A-2C The described polishing system 200 performs method 400. At activity 402, method 400 includes pressing a substrate against the surface of a polishing pad. Here, the polishing pad is disposed on and fixed to a pad mounting surface of a polishing stage. The pad mounting surface includes a plurality of polishing zones, such as a first zone having a circular or annular shape, a second zone adjacent to and surrounding the first zone, and a third zone adjacent to and surrounding the second zone. Here, the surface in the second zone is recessed from the surfaces of the first and third zones adjacent to the second zone, and the width of the second zone is smaller than the diameter of the substrate. At activity 404, the method optionally includes oscillating the substrate between the inner and outer radii of the polishing pad.

[0045] In some embodiments, method 400 further includes: at activity 406, pressing an adjustment disk against the surface of a polishing pad; at activity 408, determining the radial position of the adjustment disk relative to a polishing stage; and at activity 410, using measurements from a displacement sensor and the determined radial position of the adjustment disk to determine the thickness of the polishing pad in each of a plurality of polishing zones. In some embodiments, method 400 further includes, at activity 412, varying the adjustment dwell time or adjustment downpressure in one or more of the plurality of polishing zones based on the determined thickness of the polishing pad in one or more of the plurality of polishing zones.

[0046] Advantageously, method 400 can be used to significantly reduce the pad rebound effect at the leading and trailing edges of the polishing interface and reduce uneven polishing slurry thickness distribution thereon. Therefore, method 400 can be used to substantially eliminate or reduce undesirable “fast edge” or “slow edge” material removal rate distribution.

[0047] Although the foregoing describes embodiments of the present disclosure, other and further embodiments of the present disclosure are conceivable without departing from the basic scope of the present disclosure, and the scope of the present disclosure is defined by the appended claims.

Claims

1. A polishing system, comprising: A substrate carrier, the substrate carrier including an annular retainer configured to surround the substrate during a polishing process; as well as A polishing workbench, comprising a cylindrical metal body having a pad mounting surface, wherein... The pad mounting surface includes multiple polished areas, including a first area having a circular or annular shape, a second area adjacent to the first area, and a third area adjacent to the second area. At least a portion of the pad mounting surface in the first region and the third region defines a plane. The plane is orthogonal to the rotation axis of the polishing table. The pad mounting surface in the second region is recessed from the plane. The width of the second region is smaller than the outer diameter of the annular buckle, and The pad mounting surface in the third zone slopes upward from the pad mounting surface in the second zone, intersecting the circumferential edge of the polishing table at an acute angle.

2. The polishing system of claim 1, wherein at least a portion of the pad mounting surface in the second region is recessed from the plane by a distance of 20 μm or greater.

3. The polishing system of claim 1, further comprising a pad adjuster assembly including an adjuster arm for sweeping an adjusting disk across the surface of a polishing pad disposed on the polishing table, wherein the adjusting disk has a diameter smaller than the width of the second region, wherein the pad adjuster assembly further includes a sensor coupled to the adjuster arm and configured to determine a distance between the adjuster arm and a surface of the polishing table disposed below the adjuster arm.

4. The polishing system of claim 3, further comprising a non-transitory computer-readable medium storing instructions, which, when executed by a processor, are used to perform a method for processing a substrate, the method comprising: The substrate is pushed against the surface of the polishing pad, which is disposed on the pad mounting surface of the polishing worktable; The adjusting disc is pushed against the surface of the polishing pad; Determine the radial position of the adjustment disk relative to the polishing worktable; The thickness of the polishing pad in each of the plurality of zones is determined using the radial position of the sensor and the adjustment disk; as well as The dwell time or the downpressure in one or more of the plurality of polishing zones is varied based on a determined thickness of the polishing pad in one or more of the plurality of polishing zones.

5. The polishing system of claim 4, wherein the method includes changing the adjustable dwell time such that per cm in the second zone 2 The adjusted dwell time for the polishing pad surface area is greater than per cm in either the first or the third zone. 2 The adjustment of the dwell time is related to the surface area of ​​the polishing pad.

6. A method for polishing a substrate, comprising: A substrate is pushed against the surface of a polishing pad using a substrate carrier. The polishing pad is disposed on the pad mounting surface of the polishing table. The pad mounting surface includes multiple polished areas, including a first area having a circular or annular shape, a second area adjacent to the first area, and a third area adjacent to the second area. At least a portion of the pad mounting surfaces in the first region and the third region define a plane. The pad mounting surface in the third zone slopes upward from the pad mounting surface in the second zone, intersecting the circumferential edge of the polishing table at an acute angle. The plane is orthogonal to the rotation axis of the polishing table, and The pad mounting surface in the second region is recessed from the plane.

7. The method of claim 6, further comprising: Push the adjustment disc against the surface of the polishing pad; Determine the radial position of the adjustment disk relative to the polishing worktable; The thickness of the polishing pad in each of the plurality of polishing zones is determined using the sensor and the radial position of the adjustment disk; as well as The dwell time or the downpressure in one or more of the plurality of polishing zones is varied based on a determined thickness of the polishing pad in one or more of the plurality of polishing zones.

8. The method of claim 7, wherein the adjusting disk has a diameter smaller than the width of the second zone.

9. The method of claim 8, wherein the adjusting disk is pushed against the polishing pad using a pad adjusting assembly, the pad adjusting assembly including an adjusting arm for sweeping the adjusting disk across the surface of the polishing pad, wherein... The sensor is coupled to the regulator arm, and The sensor is configured to determine the distance between the adjuster arm and the surface of the polishing stage disposed below the adjuster arm.

10. The method of claim 9, wherein in the second region, every cm 2 The adjusted dwell time for the polishing pad surface area is greater than per cm in either the first or the third zone. 2 The adjustment of the dwell time is related to the surface area of ​​the polishing pad.

11. The method of claim 6, wherein The substrate carrier includes an annular retaining ring that surrounds the substrate. The width of the second zone is smaller than the outer diameter of the annular buckle.

12. The method of claim 11, wherein at least a portion of the pad mounting surface in the second region is recessed from the plane by a distance of 20 μm or greater.

13. A polishing worktable, comprising: A cylindrical metal body, wherein the cylindrical metal body has a pad mounting surface, wherein The pad mounting surface includes multiple polished areas, including a first area having a circular or annular shape, a second area adjacent to the first area, and a third area adjacent to the second area. The pad mounting surface in the third zone slopes upward from the pad mounting surface in the second zone, intersecting the circumferential edge of the polishing table at an acute angle. At least a portion of the pad mounting surfaces in the first region and the third region define a plane. The plane is orthogonal to the rotation axis of the polishing table, and The pad mounting surface in the second region is recessed from the plane.

14. The polishing workbench of claim 13, wherein at least a portion of the pad mounting surface in the second region is recessed from the plane by a distance of 20 μm or greater.

15. The polishing table of claim 14, wherein the pad mounting surface comprises a fluoropolymer material coating, and the recessed surface of the second region is at least partially formed in the polymer material.

16. The polishing table of claim 14, wherein the recessed surface of the second region is at least partially formed in the cylindrical metal body, and the pad mounting surface comprises a fluoropolymer material coating disposed on the cylindrical metal body.

17. The polishing worktable as claimed in claim 13, wherein... The inner radius of the second region is greater than 0.15 times the radius of the pad mounting surface. The outer radius of the second region is less than 0.85 times the radius of the pad mounting surface, and The width of the second region is at least 0.15 times the radius of the pad mounting surface.

Images