TW201609313A - Method, system and polishing pad for chemical mechancal polishing - Google Patents

Abstract

Chemical mechanical polishing can be used for "touch-up polishing" in which polishing is performed on a limited area of the front surface of the substrate. The contact area between the polishing pad and the substrate can be substantially smaller than the radius surface of the substrate. During polishing, the polishing pad can undergo an orbital motion. The polishing pad can be maintained in a fixed angular orientation during the orbital motion. The contact area can be arc-shaped. The contact area can be provided by one or more lower portions projecting downward from an upper portion of the polishing pad. A perimeter portion of the polishing pad can be vertically fixed to an annular member and a remainder of the polishing pad within the perimeter portion can be vertically free.

Description

Method, system and polishing pad for chemical mechanical polishing

This invention relates to the architecture of a chemical mechanical polishing (CMP) system.

An integrated circuit is typically formed on a substrate by continuously depositing a conductive, semiconductive, or insulating layer on the germanium wafer. One manufacturing step involves depositing a filler layer over the non-planar surface and planarizing the filler layer. For some applications, the filler layer is planarized until the top surface of the patterned layer is exposed. For example, a layer of conductive filler can be deposited over the patterned insulating layer to fill the trenches or holes in the insulating layer. After planarization, portions of the remaining metal layer between the raised patterns of the insulating layer form vias, plugs, and wires that provide a conductive path between the thin film circuits on the substrate. For other applications such as oxide milling, the filler layer is planarized until a predetermined thickness is left on the non-planar surface. In addition, photolithography typically requires planarization of the substrate surface.

Chemical mechanical polishing (CMP) is a well-established planarization method. This planarization method typically requires mounting a substrate on a carrier head or a polishing head. The exposed surface of the substrate is typically placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to urge the carrier head against the polishing pad. The abrasive slurry is typically supplied to the surface of the polishing pad.

The present invention provides systems and apparatus for substrate polishing (e.g., "trimming") in which grinding is performed on a restricted area of the front surface of the substrate.

In one aspect, the chemical mechanical polishing system includes a substrate support, a movable liner support, and a drive system. The substrate support is configured to hold the substrate in a substantially fixed angular orientation during the lapping operation. The movable pad support is configured to hold a polishing pad having a diameter no greater than a radius of the substrate. The drive system is configured to move the pad support and the polishing pad during orbital motion while the polishing pad is in contact with the upper surface of the substrate. The orbital motion has a track radius that is no greater than the diameter of the polishing pad and maintains the polishing pad in a fixed angular orientation relative to the substrate.

Implementations may include one or more of the following features. The polishing pad can have a contact area that contacts the substrate. The diameter of the contact area can be between about 1% and 10% of the diameter of the substrate. The track radius can be between about 5% and 50% of the diameter of the contact area. The drive system can include a recess in the pad support head, a rotatable cam extending into the recess, and a motor coupled to the cam. The linkage set can couple the pad support head to the fixed support to prevent rotation of the pad support head. The positioning drive system can move the pad support head laterally across the substrate. The positioning drive system can include two linear actuators configured to move the pad support head in two perpendicular directions.

In another aspect, the chemical mechanical polishing system includes a substrate support, a polishing pad, a movable pad support, and a drive system. The substrate support is configured to hold in a substantially fixed angular orientation during the grinding operation Substrate. The polishing pad has a contact area that contacts the substrate, the contact area having a diameter that is no greater than the radius of the substrate. The movable pad support is configured to hold the polishing pad. The drive system is configured to move the pad support and the polishing pad during orbital motion while the contact area of the polishing pad is in contact with the upper surface of the substrate. The orbital motion has a track radius that is no greater than the diameter of the polishing pad and maintains the polishing pad in a fixed angular orientation relative to the substrate.

Implementations may include one or more of the following features. The polishing pad may include a raised portion from the layer, and the bottom surface of the protruding portion may provide a contact area. At least one of the pressure sensitive adhesive or the holder can hold the polishing pad on the pad support. The contact area can be dished or curved.

In another aspect, the method of chemical mechanical polishing comprises: contacting a polishing pad with a substrate in a contact area having a diameter no greater than a radius of the substrate; and a contact area between the polishing pad and a surface above the substrate The contact also produces relative motion between the polishing pad and the substrate. The relative motion includes orbital motion having an orbital radius that is no greater than the diameter of the polishing pad. The polishing pad is maintained in a substantially fixed angular orientation relative to the substrate during orbital motion.

Implementations may include one or more of the following features. The substrate can be held in a fixed lateral position during orbital motion. During orbital motion, the polishing pad may be swept across the substrate at a speed no greater than about 5% of the instantaneous velocity of the orbital motion.

In another aspect, a chemical mechanical polishing system includes: a substrate support configured to hold a substrate during a grinding operation; a polishing pad support; a polishing pad held by the pad support; and a drive system configured to A relative movement between the substrate support and the polishing pad support is produced. The polishing pad has an upper portion that is fastened to the polishing pad support and a lower portion that projects downward from the upper portion. The upper surface of the upper portion is adjacent to the polishing pad support. The bottom surface of the lower portion provides a contact surface that contacts the top surface of the substrate during grinding. The contact surface is smaller than the top surface of the substrate. The upper portion has a first lateral dimension and the lower portion has a second lateral dimension that is smaller than the first lateral dimension.

Implementations may include one or more of the following features. The polishing pad support can include a sheet having a surface that spans the polishing pad, and substantially the entire upper surface of the portion above the polishing pad can abut the surface of the sheet. The adhesive holds the polishing pad on the pad support. The polishing pad support may include an annular member, the peripheral portion of the upper surface of the upper portion of the polishing pad may abut the annular member, and the remaining portion of the upper surface within the peripheral portion may not contact the polishing pad support. One or more grips can hold a peripheral section of the polishing pad on the pad support. The upper portion of the polishing pad can include a flexure section that has greater flexibility than a section of the polishing pad above the contact surface. The upper portion of the polishing pad may comprise a polyethylene terephthalate sheet.

A plurality of grooves for slurry transport may be formed on the contact surface of the lower portion of the polishing pad. The plurality of grooves may have a depth that is less than the thickness of the lower portion. At least some of the plurality of grooves may extend completely across the lower portion of the polishing pad. The pressure chamber may be formed by an internal chamber of the polishing pad support, the chamber may have an opening facing the substrate, and the opening may be sealed by a polishing pad coupled to the polishing pad support. Multiple numbers can be formed in the upper surface of the polishing pad The apertures, and the plurality of projections from the polishing pad support, can be assembled into the plurality of apertures to align the lower portion relative to the polishing pad support.

In another aspect, the polishing pad includes an upper portion and one or more lower portions. The upper portion has an upper surface attached to the pad carrier and a first lateral dimension. One or more lower portions project downward from the upper portion. The bottom surface of the one or more lower portions provides a contact surface that contacts the substrate during chemical mechanical polishing. Each lower portion has a second lateral dimension that is smaller than the first lateral dimension. The total surface area of the contact surface from one or more lower portions does not exceed 10% of the surface area of the upper surface.

Implementations may include one or more of the following features. At least the lower portion can include a polymeric body having a substantially uniform composition and having a plurality of pores distributed within the body. The polishing pad can include an abrasive layer and a lower portion that projects downwardly can be formed in the abrasive layer. The liner can include a backing layer that is softer than the abrasive layer. A groove for slurry transport may be formed on the bottom surface of one or more lower portions. One or more lower portions may be composed of a single protrusion. The abrasive layer can include a flexible lateral section that is thinner than a transverse section that makes up the abrasive area. The lower portion can include a microporous polyurethane.

In another aspect, a chemical mechanical polishing system includes: a substrate support configured to hold a substantially circular substrate during a grinding operation; a polishing pad support; a polishing pad held by the pad support; and a drive system The configuration is configured to produce a relative motion between the substrate support and the polishing pad support. The polishing pad has an arcuate contact area and is defined by an arcuate contact area The center point of the arc is substantially aligned with the center of the substrate held by the substrate support.

Implementations may include one or more of the following features. The width of the arc defined by the curved contact area may be between 1 mm and 3 mm, and the length of the arc may be equal to or greater than 30 mm. At least one of the pressure sensitive adhesive or the holder can hold the polishing pad on the pad support head. The relative motion between the substrate support and the polishing pad support can be an orbital motion that maintains the polishing pad support in a fixed angular orientation. The relative motion can rotate about the center of the substrate.

In another aspect, the abrasive assembly includes a polishing pad support and a polishing pad held by the liner support. The polishing pad support includes an annular member and a recess having an opening facing the substrate. The polishing pad has an abrasive surface that contacts the substrate during grinding. The peripheral portion of the polishing pad is vertically fixed to the annular member and the remaining portion of the polishing pad in the peripheral portion is freely perpendicular. The substrate-facing opening of the polishing pad support is sealed by a polishing pad to define a pressurizable chamber to provide an adjustable pressure on the back surface of the polishing pad.

Implementations may include one or more of the following features. The adhesive can secure the peripheral portion of the polishing pad to the annular member. One or more grips can hold a peripheral section of the polishing pad on the annular member. The polishing pad support can include a base and a film secured to the base, the volume between the base and the film defining a second pressurizable chamber such that the outer surface of the film provides a second surface on the back surface of the polishing pad Adjustable pressure. The membrane and the second pressurizable chamber can be configured such that the pressure in the second pressurizable chamber controls the lateral dimension of the abrasive surface against the load region of the substrate.

In another aspect, the polishing pad includes an upper portion, one or more lower portions, and a plurality of holes. The upper portion has an upper surface attached to the pad carrier and a first lateral dimension. One or more lower portions project downward from the upper portion. The bottom surface of the one or more lower portions provides a contact surface that contacts the substrate during chemical mechanical polishing. Each of the lower portions has a second lateral dimension that is smaller than the first lateral dimension such that the upper portion projects through all of the lateral sides of the lower portion. A plurality of holes are located in the upper surface of the upper portion to receive the projections from the spacer carrier. Holes are placed in sections of the upper portion of the lower portion of the polishing pad that are laterally outward.

Implementations may include one or more of the following features. A plurality of holes can be placed at the corners of the polishing pad. The polishing pad can be rectangular. One or more lower portions may have curved contact surfaces. A plurality of grooves for slurry transport may be formed on the contact surface of the lower portion of the polishing pad.

Advantages of the invention may include one or more of the following.

Small pads that undergo orbital motion can be used to compensate for non-concentric grinding uniformity. Orbital motion can provide acceptable polishing rates while avoiding overlap of pads having areas that are not intended to be ground, thereby improving substrate uniformity. Additionally, maintaining orbital motion of the polishing pad relative to the fixed orientation of the substrate can provide a more uniform polishing rate across the positively ground region than rotation.

The wider portion of the top portion of the polishing pad secured to the polishing pad support than the bottom raised portion in contact with the substrate increases the area available for the pad to be attached to the support (e.g., by pressure sensitive adhesive attachment). This can make the polishing pad less susceptible to delamination during the grinding operation.

A polishing pad having an arcuate contact area contacting the substrate provides an improved polishing rate while maintaining a satisfactory radial resolution of the abrasive region.

The alignment features ensure that the restricted contact area of the polishing pad is placed laterally relative to the pad support in a known position, thereby reducing the likelihood of grinding an undesired area of the substrate.

Providing a portion of the deflected polishing pad reduces deflection of portions of the contact surface of the polishing pad, thereby improving the likelihood that the ground area will match the operator's expectations.

The grooves in the projections of the polishing pad promote the transport of the slurry, and thus the polishing rate can be improved.

A portion of the polishing pad that is not in contact with the substrate can be formed from a lower cost material, thereby reducing the overall cost of the liner.

A liner carrier that allows control of a portion of the contact area against the substrate load allows the load area to match the spot size to be ground, thereby improving throughput while avoiding the undesired areas of the substrate being polished.

In general, non-uniform polishing of the substrate can be reduced, and the resulting flatness and smoothness of the substrate can be improved.

Other aspects, features, and advantages of the invention will be apparent from the description and drawings.

5‧‧‧Contact area/disc geometry

10‧‧‧Substrate

12‧‧‧ surface

20‧‧‧ orbital radius

22‧‧‧Contact area diameter

60‧‧‧埠

65‧‧‧Slurry

91‧‧‧Central Processing Unit

92‧‧‧ memory

93‧‧‧Support circuit

99‧‧‧ Controller

100‧‧‧ grinding equipment

105‧‧‧Substrate support

106‧‧‧Vacuum chuck/substrate support

110‧‧‧ polishing pad

111‧‧‧Clamping components

112‧‧‧Ring Clamp Ring/Curve Clamp

113‧‧‧Actuator

114‧‧‧Flange

116‧‧‧Upper surface

122‧‧‧ chamber

124‧‧‧埠

129‧‧‧ pump

131‧‧‧ Keeper

200‧‧‧ polishing pad

203‧‧‧ polishing pad

204‧‧‧ polishing pad

231‧‧‧Binder

250‧‧‧Abrased surface

258‧‧‧Abrased surface

260‧‧‧lower part/bottom part/protrusion

263‧‧‧ bottom part

Section 267‧‧‧

270‧‧‧上上

273‧‧‧Top part

274‧‧‧ upper part

275‧‧‧上上

Section 285‧‧‧

299‧‧‧ slot

300‧‧‧ polishing pad support

311‧‧‧ lower surface

315‧‧‧ polishing pad support

317‧‧‧Base

320‧‧‧ wall

325‧‧‧ chamber

327‧‧‧ recess

405‧‧‧film

406‧‧‧ chamber

410‧‧‧Clamping parts

426‧‧‧室

500‧‧‧grinding drive system

506‧‧‧Actuator

508‧‧‧ actuator

509‧‧‧Actuator

510‧‧‧arm

550‧‧‧Support structure

560‧‧‧ Positioning drive system

562‧‧‧Linear actuator

564‧‧‧Linear actuator

610‧‧‧ polishing pad

620‧‧‧Central motor output shaft

625‧‧‧ cam

630‧‧‧Anti-rotation link

809‧‧‧Load area

810‧‧‧Load area

901‧‧‧Contact area

910‧‧‧Mechanical system base

912‧‧‧Anti-rotation link

915‧‧‧Actuator

920‧‧‧pad holder

922‧‧‧ cam

924‧‧‧Motor output shaft

928‧‧‧ recess

990‧‧‧Rotary axis

1032‧‧‧Adhesive layer

1052‧‧‧ Backing layer

1062‧‧‧Abrasive layer/upper section

1064‧‧‧Upper section

1066‧‧‧Next section

1221‧‧‧上上

1222‧‧‧lower part/protrusion

1301‧‧‧Contact area

1402‧‧‧ recess

1404‧‧‧pins

1406‧‧‧ edge

1900‧‧‧ bottom surface

1903‧‧ Center

1 is a schematic cross-sectional side view of a polishing system; and FIG. 2 is a schematic cross-sectional side view of an embodiment of a polishing system including a vacuum chuck to hold a substrate; Figure 3 is a schematic cross-sectional side view of an embodiment of a polishing system having a polishing pad that does not include a downward convex portion; and Figure 4 is an embodiment of a polishing system having a polishing pad with an upper layer and a downward convex portion. A schematic cross-sectional side view of the upper layer having a larger diameter than the substrate and the downward convex portion having a smaller diameter than the substrate; and FIG. 5 is a view showing the polishing pad moving in the track while maintaining a fixed angular orientation Schematic cross-sectional top view; Figure 6 is a schematic cross-sectional top view of the polishing pad support and drive train system of the polishing system; Figure 6A is a schematic cross-sectional top view of the system of Figure 6 associated with the substrate; Figure 2 is a schematic cross-sectional plan view of the system of Figure 6 rotated about a quarter with respect to Figure 6A; Figure 7A is an illustration of a movable polishing pad support attached to a polishing pad having a plurality of clamping members Cross-sectional side view; Figure 7B is a schematic cross-sectional view of an embodiment of a movable polishing pad support comprising an inner pressurized space surrounded by an inner membrane; Figure 8A is a diagram of Figure 7B in a low pressure state it can move A schematic cross-sectional side view of the sanding pad support; FIG. 8B is a schematic cross-sectional side view of the movable polishing pad support of FIG. 7B in a high pressure state; FIG. 9 is a schematic view of the contact area of the polishing pad 5A and 10B are schematic cross-sectional side views of an embodiment of a polishing pad; Figure 11 is a schematic cross-sectional side view of another embodiment of a movable polishing pad support; Figure 12 is a schematic top plan view of an embodiment of a polishing system having a polishing pad with an arcuate raised layer, The arcuate relief layer forms a corresponding arcuate load region; and Fig. 13 is a schematic cross-sectional side view of an embodiment of a grinding system having an arcuate abrading surface that undergoes orbital motion.

Figure 14 is a schematic top view of the polishing pad.

The same component symbols in the various drawings indicate the same components.

1 Introduction

Some grinding processes result in uneven thickness across the surface of the substrate. For example, a bulk polishing process can result in under-grinding areas on the substrate. To solve this problem, after the block is polished, it is possible to perform a "trimming" polishing process that concentrates on the under-grinded substrate portion.

In the bulk polishing process, grinding occurs on the entire front surface of the substrate, even though it may be ground at different rates in different regions of the front surface. It is not the entire surface of the substrate that can undergo grinding at a given instant in the bulk polishing process. For example, a portion of the surface of the substrate may not be in contact with the polishing pad due to the presence of a groove in the polishing pad. Nonetheless, during the bulk polishing process, the portion is not positioned due to the relative motion between the polishing pad and the substrate such that the entire front surface of the substrate undergoes a certain amount of grinding.

In contrast, in a "trimming" polishing process, the polishing pad can be contacted less than the entire front surface of the substrate. Additionally, the range of motion of the polishing pad relative to the substrate is configured such that during the trimming process, the polishing pad only contacts a localized area of the substrate and a larger portion of the front surface of the substrate (eg, at least 50%, at least 75%, or At least 90%) never touch the polishing pad and are therefore not subject to grinding. For example, in a trim polishing, the contact area can be substantially smaller than the radius surface of the substrate.

As noted above, some bulk grinding processes result in non-uniform grinding. In particular, some bulk grinding processes result in localized non-concentric and non-uniform points of insufficient grinding. In a trimming process, a polishing pad that rotates around the center of the substrate can compensate for non-uniform concentric rings, but may not address local non-concentric and non-uniform points, such as angular asymmetry in the thickness distribution. However, small pads (eg, small pads that experience orbital motion) can be used to compensate for non-concentric grinding uniformity. For some implementations, the polishing pad can undergo orbital motion with a fixed angular orientation during grinding.

Referring to FIG. 1, a polishing apparatus 100 for polishing a partial region of a substrate includes a substrate support 105 that holds the substrate 10 and a movable polishing pad support 300 that holds the polishing pad 200. The polishing pad 200 includes an abrasive surface 250 having a smaller diameter than the radius of the substrate 10 being polished.

The polishing pad support 300 is suspended from the grinding drive system 500, which will provide movement of the polishing pad support 300 relative to the substrate 10 during the grinding operation. The abrasive drive system 500 can be suspended from the support structure 550.

In some implementations, the positioning drive system 560 is coupled to the substrate support 105 and/or the polishing pad support 300. For example, the abrasive drive system 500 can provide a connection between the positioning drive system 560 and the polishing pad support 300. The positioning drive system 560 is operable to position the pad support 300 at a desired lateral position above the substrate support 105. For example, support structure 550 can include two linear actuators 562 and 564 that are oriented perpendicular to each other above substrate support 105 to provide positioning drive system 560. Alternatively, the substrate support 105 can be supported by two linear actuators. Alternatively, the substrate support 105 can be rotatable, and the polishing pad support 300 can be suspended from a single linear actuator that provides movement in a radial direction. Alternatively, the polishing pad support can be suspended from the rotary actuator 508 and the substrate support 105 can be rotated using the rotary actuator 506.

Vertical actuators (illustrated by 506 and/or 508) may be coupled to substrate support 105 and/or polishing pad support 300, as appropriate. For example, the substrate support 105 can be coupled to a vertically drivable piston that can raise or lower the substrate support 105.

The grinding apparatus 100 includes a crucible 60 to dispense a slurry 65, such as an abrasive slurry, onto the surface 12 of the substrate 10 to be polished. The polishing apparatus 100 can also include a polishing pad conditioner to abrade the polishing pad 200 to maintain the polishing pad 200 in a consistent abrasive state.

In operation, the substrate 10 is loaded onto the substrate support 105, such as by a robot. Positioning drive system 500 places polishing pad support 300 and polishing pad 200 at desired locations on substrate 10 and is vertically actuated The 506 moves the substrate into contact with the polishing pad 200 (or vice versa using the actuator 508). The abrasive drive system 500 produces relative motion between the polishing pad support 300 and the substrate support 105 to initiate grinding of the substrate 10.

During the grinding operation, the positioning drive system 560 can securely hold the polishing drive system 500 and the substrate 10 substantially relative to each other. For example, the positioning system can hold the grinding drive system 500 stationary relative to the substrate 10 or can sweep the grinding drive system 500 slowly (as compared to the motion provided by the grinding drive system 500 to the substrate 10). For example, the instantaneous speed that the positioning drive system 500 provides to the substrate can be less than 5% of the instantaneous speed provided by the grinding drive system 500 to the substrate, for example, less than 2%.

The grinding system also includes a controller 90, such as a programmable computer. The controller may include a central processing unit 91, a memory 92, and a support circuit 93. The central processing unit 91 of the controller 90 executes instructions loaded from the memory 92 via the support circuit 93 to allow the controller to receive inputs and control various actuators and drive systems based on the environment and desired grinding parameters.

For the "trimming" grinding operation, the controller 90 is programmed to control the positioning drive system 560 such that even if the grinding drive system 500 is being swept slowly, the range of motion of the grinding drive system 500 is limited such that during the trimming process A significant portion (eg, at least 50%, at least 75%, or at least 90%) of the front surface of the substrate never contacts the polishing pad and is therefore not subject to grinding.

2. Grinding system

A. Substrate support

Referring to Figure 1, the substrate support 105 is a plate-like body located below the polishing pad support. The body upper surface 116 provides a load area that is large enough to accommodate the substrate to be processed. For example, the substrate can be a 200 mm to 450 mm diameter substrate. The upper surface 116 of the substrate support 105 contacts the back surface of the substrate 10 (i.e., the unground surface) and maintains the position of the back surface.

The substrate support 105 has a radius that is about the same or greater than the substrate 10. In some implementations, the substrate support 105 is slightly narrower than the substrate (see, for example, Figure 2), for example, less than 1% to 2% of the diameter of the substrate. When placed on the support member 105, the edge of the substrate 10 slightly protrudes beyond the edge of the support member 105. This provides clearance for the edge clamping robot to place the substrate on the support. In some implementations, the substrate support 105 is wider than the substrate. In this case, a robot having an end effector with a vacuum chuck can be used to place the substrate on the support. In either case, the substrate support 105 can be in contact with most of the surface on the back side of the substrate.

In some implementations, as shown in FIG. 1, the substrate support 105 maintains the position of the substrate 10 using the clamping assembly 111 during the lapping operation. In some implementations, the clamping assembly 111 can be a single annular clamping ring 112 that contacts the edge of the top surface of the substrate 10. Alternatively, the clamping assembly 111 can include two arcuate clips 112 that contact the edges of the top surface on opposite sides of the substrate 10. The clamp 112 of the clamp assembly 111 can be lowered by contact with the edge of the substrate by one or more actuators 113. The downward force of the clamping member inhibits the substrate during the grinding operation Lateral movement during the period. In some implementations, the one or more clips include a downwardly projecting flange 114 that surrounds the outer edge of the substrate.

In some implementations, as shown in FIG. 2, the substrate support 105 is a vacuum chuck 106. The vacuum chuck 106 includes a chamber 122 and a plurality of turns 124 that connect the chamber 122 to the surface 116 of the support substrate 10. In operation, air may be expelled from the chamber 122, such as by pump 129, to apply suction through the crucible 124 to hold the substrate in place on the substrate support 106.

In some implementations, as shown in FIG. 3, the substrate support 105 includes a holder 131. The holder 131 can be attached to the surface 116 of the support substrate 10 and protrude above the surface. Typically, the holder is at least as thick as the substrate 10 (measured perpendicular to the surface 12). In operation, the holder 131 surrounds the substrate 10. For example, the retainer 131 can be an annular body having a diameter that is slightly larger than the diameter of the substrate 10. The friction from the polishing pad 200 can create a lateral force on the substrate 10 during grinding. However, the holder 131 limits the lateral movement of the substrate 10.

The various substrate support features described above may be combined with each other as appropriate. For example, the substrate support can include both a vacuum chuck and a holder.

Additionally, while the illustrated substrate support configuration is illustrated for ease of illustration in conjunction with the pressure sensitive adhesive movable pad support, such configurations may be in any of the embodiments of the pad support head and/or drive system described below. Use one together.

B. Polishing pad

Referring to Figure 1, the polishing pad 200 has an abrasive surface 250 that creates contact with the substrate 10 in the contact area (also referred to as the load area) during polishing. The abrasive surface 250 can have a smaller diameter than the radius of the substrate 10. For example, the diameter of the abrasive surface can be from about 5% to about 10% of the diameter of the substrate. For example, for wafers having diameters ranging from 200 mm to 300 mm, the diameter of the abrasive surface can be between 10 mm and 30 mm. Smaller abrasive surfaces provide more precision but lower yields.

In some embodiments, less than 1% of the surface of the substrate can be in contact with the abrasive surface at any given time. In general, although this can be used for dressing grinding operations, this small area is not acceptable for bulk grinding operations due to low throughput.

In some implementations, such as shown in FIG. 3, the entire polishing pad (eg, measured at the outer edge of the liner) has a smaller diameter than the radius of the substrate 10. For example, the diameter of the polishing pad can be from about 5% to 10% of the diameter of the substrate.

In the example of FIG. 1, a polishing pad 200 is disposed over the upper surface of the substrate 10, and the polishing pad includes an upper portion 270 coupled to the bottom of the movable pad support 300 and a lower portion having a bottom surface 250 260, the bottom surface is in contact with the substrate 10 during the grinding operation. In some cases, as shown in FIG. 1, the bottom portion 260 of the polishing pad 200 is provided by a raised portion from the wider upper portion 270. The bottom surface 250 of the raised portion 260 contacts the substrate during the grinding operation and provides an abrasive surface.

In the example of FIG. 1, the movable pad support 300 is coupled to the upper portion 270 of the polishing pad 200 using a pressure sensitive adhesive 231. The pressure sensitive adhesive 231 applied between the bottom surface of the polishing pad support 300 and the top surface of the polishing pad 200 maintains the polishing pad 200 coupled to the pad support 300 during the lapping operation.

By making the upper portion 270 of the polishing pad 200 wider than the lower portion 260, the available surface area of the adhesive 231 is increased. Increasing the surface area of the adhesive 231 improves the bond strength between the liner 200 and the liner support and reduces the risk of delamination of the polishing pad during milling.

Referring to FIG. 3, the lower portion 260 of the polishing pad 203 can have the same radius as the top portion 273. However, when the pressure sensitive adhesive 231 provides a coupling between the liner and the movable pad support 300, it is preferred that the bottom portion 263 is narrower than the top portion 273.

Referring to Figure 5, the contact area 5 of the polishing pad can be a dished geometry 5 formed by the raised portion of the dished bottom of the polishing pad.

Referring to FIGS. 9A and 9B, the contact region 901 of the polishing pad 110 in contact with the substrate 10 may be an arcuate contact region 901 formed by the arcuate projection portion 290 of the polishing pad.

Referring to FIG. 1, in some implementations, the portion 270 above the polishing pad 200 can have a smaller diameter than the substrate 10.

Referring to FIG. 4, in some implementations, the portion 274 above the polishing pad 204 can have a larger diameter than the substrate 10.

Referring to Figure 1, the polishing pad 200 can be composed of a single layer of a uniform composition. In this case, the material composition of the upper portion 270 and the lower portion 260 (also referred to as the raised portion 260) are the same.

Referring to FIG. 10B, in some implementations, the polishing pad 200 can include two or more layers of different compositions, such as the abrasive layer 1062 and the more compressible backing layer 1052. Optionally, an intermediate pressure sensitive adhesive layer 1032 can be used to secure the abrasive layer 1061 to the backing layer 1061. In this case, the upper portion 1221 can correspond to the backing layer 102 and the lower portion 1222 can correspond to the abrasive layer 1062. The polishing pad can be coupled to the polishing pad support via a pressure sensitive adhesive layer 231.

Referring to FIG. 10A, in some implementations, the polishing pad can include two or more layers having different compositions, and the polishing pad 200 upper portion 1221 can include the backing layer 1052 and the upper portion of the polishing layer 1062. 1064 both. Accordingly, the abrasive layer 1062 includes both the lower section 1066 and the upper section 1062 that provide the raised portion 1222, wherein the upper section 1064 is wider than the lower section 1066.

The polishing pad can be coupled to the polishing pad support via a pressure sensitive adhesive layer 321 .

In either of the embodiments illustrated in Figure 10A or Figure 10B, the abrasive layer 1062 can be comprised of a single layer of uniform composition. For example, in any of the embodiments shown in FIG. 10A or FIG. 10B, portions of the liner contacting the substrate may have conventional materials such as microporous polymers such as polyurethanes.

Referring to Fig. 10A, the backing layer 1052 can be relatively soft to allow for better polishing pad flexibility when spotting unevenly substrate surfaces. The abrasive layer 1064 can be a hard polyurethane.

Referring first to FIG 10B, the backing tray 1052 may be a relatively soft layer, but also by such as polyethylene terephthalate (e.g., Mylar ^TM) made of flexible material layer is incompressible. For example, this pad configuration can be used in an implementation where the polishing pad of Figure 10B is coupled to the pressurized chamber polishing pad support of Figure 11. The abrasive layer 1062 can be a hard polyurethane.

Referring to FIG. 11, in some implementations, the polishing pad 205 can include an upper portion 275 and a lower portion 260. The polishing pad 205 has a thicker lateral section 267 that includes a combined lower portion 260 and upper portion 275. The upper portion 275 extends laterally on either side of the thicker section 267 to provide a lateral side section 285. Lateral side section 285 flexes in response to pressure on thicker section 267. The thicker section 267 can have a pad thickness of about 2 mm in the abrasive zone, which is similar to a large size pad. The thickness of the liner in the flexing transverse section 285 can be about 0.5 mm.

In some implementations, the bottom surface 250 of the lower portion of the polishing pad 200 can include grooves to allow slurry to be delivered during the grinding operation. The groove 299 can be shallower than the depth of the lower portion 260 (see, for example, Figure 11). However, in some implementations, the lower portion does not include a slot. If the polishing pad includes a groove, the groove 299 can extend completely across the lateral width of the lower portion 260. Additionally, the slots may be shallower than the vertical thickness of the lower portion 260, i.e., the slots pass partially, but not completely, through the lower portion 260 in a vertical manner.

Referring to Figure 9, the bottom surface 1900 of the polishing pad 200 can be an arcuate region. If the polishing pad includes a groove, the groove 299 can extend completely across the lateral width of the arcuate region. The grooves 299 can be spaced at even intervals along the length of the curved region. Each slot 299 can extend along a radius of the center 1903 through the slot and arcuate region, or each slot 299 can be disposed at an angle (e.g., 45[deg.]) relative to the radius.

Referring to Figure 14, in some implementations, the polishing pad 200 includes alignment features that are mated with mating features on the pad support 300 to ensure the polishing pad 200 and provide the lower portion of the contact region 250. 260 is located in a known lateral position relative to pad support 300.

For example, the polishing pad 200 can include a recess 1402 formed in the back surface of the polishing pad 200. The recess 1402 can be drilled by the machine in a known position in the polishing pad relative to the contact area 250. A recess 1402 can be disposed in the thin flange or outer lateral portion 285 of the portion 270 above the polishing pad 200. The recess may extend partially or completely through the polishing pad. The pad support 300 can include pins 1404 (eg, projecting downwardly from the plate) that fit into the recess 1402.

As another example, after the contact area 250 is defined on the polishing pad 200, at least some of the edges 1406 of the polishing pad 200 can be machined. The pad support 300 can include a recess that is machined into the support sheet. The edge of the recess includes an alignment surface, and the edge 1406 of the polishing pad is positioned to abut the alignment surface of the recess in the sheet.

The lower portion 260 of the polishing pad 200 that contacts the substrate can be formed of a high quality material that satisfies, for example, rigidity, porosity, and the like. High precision specifications. However, other portions of the polishing pad that do not contact the substrate do not have to meet such high precision specifications, and thus may be formed from lower cost materials. This reduces the overall cost of the liner.

C. Pad drive system and orbital motion

Referring to FIGS. 1 and 5, the abrasive drive system 500 can be configured to move the coupled polishing pad support 300 and polishing pad 200 during orbital motion above the substrate 10 during a polishing operation. In particular, as shown in FIG. 5, the abrasive drive system 500 can be configured to maintain a polishing pad in a fixed angular orientation relative to the substrate during the lapping operation.

Referring to Figure 5, the track radius 20 of the polishing pad in contact with the substrate is preferably smaller than the diameter 22 of the contact area. For example, the track radius can be from about 5% to 50% (eg, 5%-20%) of the diameter of the contact area. For a 20 mm to 30 mm diameter contact area, the track radius can be from 1 mm to 6 mm. This achieves a more uniform velocity profile in the load zone 5. The polishing pad can be rotated in the track at a rate of 1000 to 5000 ("rpm") per minute.

Referring to Figure 6, the drive train can include a mechanical system base 910 that utilizes a single actuator 915 for orbital motion. Motor output shaft 924 is coupled to cam 922 in a connective manner. Cam 922 extends into recess 928 in polishing pad holder 920. During the grinding operation, the motor output shaft 924 rotates about the axis of rotation 990, causing the cam 922 to rotate the polishing pad holder 920. A plurality of anti-rotation links 912 extend from the mechanical system base 910 to a portion above the polishing pad holder 920 to prevent the pad holder 920 from rotating. Anti-rotation combined with the movement of cam 922 Link 912 effects orbital movement of the polishing pad support, wherein the angular orientation of the polishing pad holder 920 does not change during the grinding operation.

As depicted in Figures 6A and 6B, the orbital motion can maintain a fixed angular orientation of the polishing pad relative to the substrate during the lapping operation. As the central motor output shaft 620 rotates, the cam 625 in combination with the anti-rotation link 630 translates the rotational motion into the orbital motion of the polishing pad 610 that connects the upper mechanical system base to the polishing pad support . This achieves a more uniform velocity profile than pure rotation.

In some implementations, the grinding drive system and the positioning drive system are provided by the same components. For example, a single drive system can include two linear actuators configured to move the pad support head in two perpendicular directions. For positioning, the controller can cause the actuator to move the pad support to a desired location on the substrate. For grinding, the controller can cause the actuator to move the pad support during orbital motion, for example by applying a phase offset sinusoidal signal to the two actuators.

Referring to Figure 1, in some implementations, the abrasive drive system 500 can include two rotary actuators. For example, the polishing pad support can be suspended from the rotary actuator 508, which is then suspended from the second rotary actuator 509. During the grinding operation, the second rotary actuator 509 rotates the arm 510, which sweeps the polishing pad support 300 during orbital motion. The first rotary actuator 508 rotates, for example, in the opposite direction to the second rotary actuator 509 but at the same rotational speed to counteract the rotational motion such that the polishing pad assembly is along while remaining in a substantially fixed angular position relative to the substrate Orbital movement.

D. Pad support

The movable pad support 300 holds the polishing pad and is coupled to the grinding drive system 500.

In some embodiments, for example, as shown in Figures 1 through 4, the pad support 300 is a simple rigid sheet. The lower surface 311 of the sheet is large enough to accommodate the portion 270 above the polishing pad 200.

However, the pad support 300 can also include an actuator 508 to control the downward pressure of the polishing pad 200 against the substrate 10.

In the example in FIG. 7A, a pad support 300 is illustrated that can apply an adjustable pressure on the polishing pad 200. The pad support 300 includes a base 317 that is coupled to the grinding drive system 500. The bottom of the base 317 includes a recess 327. The pad support 300 includes a clamping member 410 that holds the edge of the polishing pad 200 on the base 317. The polishing pad 200 can cover the recess 327 to define a pressurizable chamber 426. By pumping fluid into and out of chamber 426, the downward pressure of polishing pad 200 against substrate 10 can be adjusted.

In some implementations, as shown in Figures 7B, 8A, and 8B, the pad support 300 can have an inner film 405 that defines a first pressurizable between the film 405 and the base 317. Chamber 406. The film is positioned to contact the side 275 of the polishing pad 200 away from the abrasive surface 258. The film 405 and chamber 406 are configured such that when the pad support 300 holds the polishing pad 200 during the lapping operation, the pressure in the chamber 406 controls the size of the load pad 809 of the polishing pad 200 on the substrate 10. When the pressure inside the chamber increases, the film expands the radius, thereby lining A larger portion of the raised portion of the bottom portion of the pad applies pressure and thus increases the area of the load region 810. When the pressure is reduced, the result is a smaller size load zone 809.

Referring to FIG. 11, in some implementations, the polishing pad support 315 can include an inner pressurizable chamber 325 formed by the wall 320 of the polishing pad support 315. The chamber 325 can have an opening 327 that faces the substrate. The opening 327 can be sealed by, for example, fastening the polishing pad 200 to the polishing pad support 315 by the clamping member 410. During the grinding operation, the pressure in the pressure chamber 425 can be dynamically controlled, for example, by a controller and a hydraulic pump to adjust to a non-uniform point of positive grinding.

Referring to Fig. 12, in some implementations, the contact area 1301 of the polishing pad 20 can be an arcuate area. For example, the protruding portion may be curved. The drive system 500 can rotate the arc about the center 1302 of the substrate 10.

Referring to FIG. 13, in some embodiments, the polishing pad 200 contact region 901 can be an arcuate region that undergoes orbital motion relative to the substrate 10.

3. Conclusion

The spot size of the non-uniformity on the substrate will indicate the desired size of the contact area during the grinding of the spot. If the contact area is too large, correction of insufficient grinding of some areas on the substrate can result in excessive grinding of other areas. On the other hand, if the contact area is too small, the liner will need to move across the substrate to cover the under-grinding area, thereby reducing throughput.

In the substrate processing operation, the substrate may first undergo a bulk polishing process in which grinding is performed on the entire front surface of the substrate. Optionally, after the bulk grinding operation, the non-uniformity of the substrate can be measured, for example, within a production line or at an independent measuring station. The substrate can then be transferred to the grinding apparatus 100 and subjected to a finishing polishing process. Control of the area to be ground at the grinding apparatus may be based on the identification of under-grinding areas of the substrate from historical data (eg, thickness measurements produced during quality qualification) or substrate measurements from within the production line or at independent measurement stations .

The entire grinding system can be arranged with the front surface of the substrate disposed vertically or face down (relative to gravity). However, the advantage of having the front surface of the substrate face up is here to allow the slurry to be distributed on the surface of the substrate. This can improve slurry retention and thus reduce slurry usage due to the larger size of the substrate relative to the abrasive surface of the polishing pad.

Numerous embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, in some embodiments, the substrate support can include its own actuators that are capable of moving the substrate into position relative to the polishing pad. As another example, while the system described above includes a drive system that moves the polishing pad in the track while holding the substrate in a substantially fixed position, the polishing pad can be held in a substantially fixed position and moved in the track. In this case, the grinding drive system can be a similar drive system but coupled to the substrate support rather than the polishing pad support. Although a generally circular substrate is used, this is not required and the support and/or polishing pad Other shapes such as a rectangle (in this case, the "radius" or "diameter" will generally be adapted to the lateral dimension along the major axis).

Accordingly, other embodiments are within the scope of the following claims.

10‧‧‧Substrate

12‧‧‧ surface

60‧‧‧埠

65‧‧‧Slurry

91‧‧‧Central Processing Unit

92‧‧‧ memory

93‧‧‧Support circuit

99‧‧‧ Controller

100‧‧‧ grinding equipment

105‧‧‧Substrate support

111‧‧‧Clamping components

112‧‧‧Ring Clamp Ring/Curve Clamp

113‧‧‧Actuator

114‧‧‧Flange

116‧‧‧Upper surface

200‧‧‧ polishing pad

231‧‧‧Binder

250‧‧‧Abrased surface

260‧‧‧lower part/bottom part/protrusion

270‧‧‧上上

300‧‧‧ polishing pad support

311‧‧‧ lower surface

500‧‧‧grinding drive system

506‧‧‧Actuator

508‧‧‧ actuator

509‧‧‧Actuator

510‧‧‧arm

550‧‧‧Support structure

560‧‧‧ Positioning drive system

562‧‧‧Linear actuator

564‧‧‧Linear actuator

Claims (50)

A chemical mechanical polishing system comprising: a substrate support configured to hold a substrate during a grinding operation; a polishing pad support; a polishing pad held by the pad support, the polishing pad having a fastening to An upper portion of the polishing pad support and a lower portion projecting downward from the upper portion, wherein an upper surface of the upper portion abuts the polishing pad support, and a bottom surface of the lower portion provides contact during grinding a contact surface of a top surface of the substrate, the contact surface being smaller than the top surface of the substrate, and the upper portion has a first lateral dimension and the lower portion has a second lateral dimension, the second lateral dimension being The first lateral dimension is small; and a drive system configured to produce relative motion between the substrate support and the polishing pad support. The chemical mechanical polishing system of claim 1, wherein the polishing pad support comprises a plate having a surface spanning the polishing pad, and substantially the entire upper surface of the upper portion of the polishing pad abuts the plate The surface. The CMP system of claim 2, further comprising an adhesive that holds the polishing pad on the liner support. The chemical mechanical polishing system of claim 1, wherein the polishing pad support comprises an annular member, a peripheral portion of one of the upper surfaces of the upper portion of the polishing pad abuts the annular member, and the peripheral portion The remaining portion of one of the upper surfaces does not contact the polishing pad support. The CMP system of claim 4, further comprising one or more grips on which a peripheral section of the polishing pad is retained. The CMP system of claim 4, wherein the upper portion of the polishing pad comprises a flexing section having a larger extent than a section of the polishing pad above the contact surface flexibility. The CMP system of claim 6, wherein the upper portion of the polishing pad comprises a polyethylene terephthalate sheet. The chemical mechanical polishing system of claim 1, further comprising a plurality of grooves for slurry transport on the contact surface of the lower portion of the polishing pad. The CMP system of claim 7, wherein the plurality of grooves have a depth that is less than a thickness of one of the lower portions. The CMP system of claim 7, wherein at least some of the plurality of grooves are completed across the lower portion of the polishing pad Fully extended. The chemical mechanical polishing system of claim 1, further comprising a pressure chamber formed by an inner chamber of the polishing pad support, the chamber having an opening facing the substrate, and A polishing pad is coupled to the polishing pad support to seal the opening. The chemical mechanical polishing system of claim 1, comprising a plurality of holes in the upper surface of the polishing pad, and a plurality of protrusions from the polishing pad support, the protrusions being assembled into the plurality of holes The lower portion is aligned relative to the polishing pad support. A polishing pad comprising: an upper portion having an upper surface attached to a pad carrier, the upper portion having a first lateral dimension; and one or more lower portions, the one or more a lower portion projecting downwardly from the upper portion, a bottom surface of the one or more lower portions providing a contact surface contacting a substrate during chemical mechanical polishing, each lower portion having a smaller than the first lateral dimension a second transverse dimension, and wherein the total surface area of one of the contact surfaces from the one or more lower portions does not exceed 10% of the surface area of one of the upper surfaces. The polishing pad of claim 13 wherein at least the lower portion is a polymeric body having a substantially uniform composition and having a plurality of pores distributed within the body. The polishing pad of claim 13, comprising an abrasive layer, wherein the lower portion that protrudes downward is formed in the abrasive layer. The polishing pad of claim 13, wherein the liner comprises a backing layer that is softer than the abrasive layer. The polishing pad of claim 13, further comprising a groove for slurry transport on the bottom surface of the one or more lower portions. The polishing pad of claim 13, wherein the one or more lower portions are comprised of a single protrusion. The polishing pad of claim 13 wherein the abrasive layer comprises a flexible lateral section that is thinner than the transverse section that makes up the abrasive zone. The polishing pad of claim 13, wherein the lower portion is a microporous polyurethane. A chemical mechanical polishing system comprising: a substrate support configured to hold a substrate in a substantially fixed angular orientation during a lapping operation; a movable pad support configured to hold a polishing pad, the polishing The pad has a diameter no greater than a radius of the substrate; and a drive system configured to move the pad support and the polishing pad in a orbital motion while the polishing pad is in contact with an upper surface of the substrate The orbital motion has a diameter no greater than one of the polishing pads The track pad is maintained at a radius of the track and at a fixed angular orientation relative to the substrate. The system of claim 21, further comprising the polishing pad, wherein the polishing pad has a contact area that contacts the substrate. The system of claim 22, wherein one of the contact areas has a diameter between about 1% and 10% of the diameter of the substrate. The system of claim 23, wherein the track radius is between about 5% and 50% of the diameter of the contact area. The system of claim 21, wherein the drive system includes a recess in the pad support head, a rotatable cam extending into the recess, and a motor coupled to the cam. The system of claim 25, further comprising a linkage set that couples the pad support head to a fixed support to prevent rotation of the pad support head. The system of claim 21, comprising a positioning drive system for laterally moving the pad support head across the substrate. The system of claim 27, wherein the positioning drive system comprises two linear actuators configured to move the pad support head in two perpendicular directions. A chemical mechanical polishing system comprising: a substrate support configured to hold the substrate in a substantially fixed angular orientation during a lapping operation; a polishing pad having a contact area contacting the substrate, the contact area having a diameter no greater than a radius of the substrate; a movable pad support configured to hold the polishing pad; a drive system Configuring to move the pad support and the polishing pad in an orbital motion while the contact area of the polishing pad is in contact with an upper surface of the substrate, the orbital motion having a diameter no greater than one of the polishing pads The track pad is maintained at a radius of the track and at a fixed angular orientation relative to the substrate. The system of claim 29, wherein the polishing pad comprises a raised portion from a layer, a bottom surface of the protruding portion providing the contact area. The system of claim 30, comprising at least one of a pressure sensitive adhesive or a clamping member, the pressure sensitive adhesive or at least one of the clamping members holding the polishing pad on the liner support . The system of claim 29, wherein the contact area is one of a dish or an arc. A chemical mechanical polishing method, the method comprising the steps of: causing a polishing pad to make contact with a substrate in a contact area having a diameter not greater than a radius of the substrate; the contact area of the polishing pad Producing relative motion between the polishing pad and the substrate while contacting one of the upper surfaces of the substrate, the phase The motion includes an orbital motion having an orbital radius no greater than a diameter of one of the polishing pads; and maintaining the polishing pad in a substantially fixed angular orientation relative to the substrate during the orbital motion. The method of claim 33, comprising the step of holding the substrate in a fixed lateral position during the orbital motion. The method of claim 34, further comprising the step of sweeping the polishing pad laterally across the substrate during the orbital motion at a speed no greater than about 5% of one of the orbital motions. A chemical mechanical polishing system comprising: a substrate support configured to hold a substantially circular substrate during a polishing operation; a polishing pad support; a polishing pad held by the pad support, the polishing pad having An arcuate contact area, wherein a center point of one of the arcs defined by the arcuate contact area is substantially aligned with a center of the substrate held by the substrate support; and a drive system configured to generate the Relative movement between the substrate support and the polishing pad support. The CMP system of claim 36, wherein one of the arcs defined by the arcuate contact area has a width of 1 Between mm and 3 mm, and one of the arcs has a length equal to or greater than 30 mm. The chemical mechanical polishing system of claim 36, further comprising at least one of a pressure sensitive adhesive or a holding member, the at least one of the pressure sensitive adhesive or the holding member being held on the backing support head The polishing pad. The CMP system of claim 36, wherein the relative movement between the substrate support and the polishing pad support is an orbital motion that maintains the polishing pad support in a fixed angular orientation. The CMP system of claim 36, wherein the relative motion rotates about a center of the substrate. An abrasive assembly comprising: a polishing pad support comprising an annular member and a recess having a surface facing the substrate; and a polishing pad held by the spacer support, the polishing pad having Contacting an abrasive surface of a substrate during polishing, wherein a peripheral portion of the polishing pad is vertically fixed to the annular member, and a remaining portion of the polishing pad in the peripheral portion is freely perpendicular; and wherein the polishing pad is sealed The substrate-facing opening of the polishing pad support defines a pressurizable chamber to provide an adjustable pressure on a back surface of one of the polishing pads. The abrasive assembly of claim 41, comprising an adhesive that secures the peripheral portion of the polishing pad to the annular member. The abrasive assembly of claim 41, comprising one or more grips on which the peripheral section of the polishing pad is retained. The polishing assembly of claim 41, wherein the polishing pad support comprises a base and a film secured to the base, a volume between the base and the film defining a second pressurizable chamber The outer surface of one of the films provides a second adjustable pressure on the back surface of the polishing pad. The abrasive assembly of claim 44, wherein the membrane and the second pressurizable chamber are configured such that a pressure in the second pressurizable chamber controls the abrasive surface against a load region of a substrate A horizontal dimension. A polishing pad comprising: an upper portion having an upper surface attached to a pad carrier, the upper portion having a first lateral dimension; one or more lower portions, the one or more a lower portion projecting downwardly from the upper portion, a bottom surface of the one or more lower portions providing a contact surface contacting a substrate during chemical mechanical polishing, each lower portion having a smaller than the first lateral dimension Second lateral dimension Having the upper portion projecting through all of the lateral sides of the lower portion; and a plurality of apertures in the upper surface of the upper portion for receiving projections from the spacer carrier, the apertures being disposed in the lower portion Transversely outward in one of the sections of the upper portion of the polishing pad. The polishing pad of claim 46, wherein the plurality of holes are disposed at a corner of the polishing pad. The polishing pad of claim 47, wherein the polishing pad is rectangular. The polishing pad of claim 48, wherein the one or more lower portions have an arcuate contact surface. The polishing pad of claim 46, further comprising a plurality of grooves for slurry transport on the contact surface of the lower portion of the polishing pad.