TWI692385B - 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

The invention relates to a structure of a chemical mechanical polishing (CMP) system.

Generally, an integrated circuit is formed on a substrate by continuously depositing conductive, semiconductive, or insulating layers on a silicon 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 conductive filler layer can be deposited on the patterned insulating layer to fill the trench or hole in the insulating layer. After planarization, portions of the remaining metal layer between the raised patterns of the insulating layer form through holes, plugs, and wires, and these through holes, plugs, and wires provide conductive paths between the thin film circuits on the substrate. For other applications such as oxide grinding, the filler layer is planarized until a predetermined thickness is left on the non-planar surface. In addition, photolithography usually requires planarization of the substrate surface.

Chemical mechanical polishing (CMP) is a recognized method of planarization. This planarization method usually requires mounting the substrate on the carrier head or the grinding head. The exposed surface of the substrate is usually placed against the rotating polishing pad. The carrier head provides a controllable load on the substrate to push the carrier head against the polishing pad. Abrasive slurry is usually supplied to the surface of the polishing pad.

The present invention provides a system and apparatus for substrate polishing (eg, "dressing polishing"), where the polishing is performed on a limited area of the front surface of the substrate.

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

The implementation plan may include one or more of the following features. The polishing pad may have a contact area that contacts the substrate. The diameter of the contact area may be between about 1% and 10% of the diameter of the substrate. The track radius may be between about 5% and 50% of the diameter of the contact area. The drive system may include a recess in the cushion support head, a rotatable cam extending into the recess, and a motor connected to the cam. The link 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 may include two linear actuators configured to move the pad support head in two vertical 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 be held 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 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 in orbital motion while the contact area of the polishing pad is in contact with the upper surface of the substrate. The orbital motion has an orbital radius no greater than the diameter of the polishing pad and maintains the polishing pad in a fixed angular orientation relative to the substrate.

The implementation plan may include one or more of the following features. The polishing pad may include a protruding 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 clamping member can hold the polishing pad on the pad support. The contact area may be dish-shaped or arc-shaped.

In another aspect, the method of chemical mechanical polishing includes: contacting the polishing pad with the substrate in a contact area, the contact area having a diameter no greater than the radius of the substrate; and contacting the polishing pad with the upper surface of the substrate At the same time, the relative movement between the polishing pad and the substrate is generated. The relative motion includes an orbital motion having an orbital radius not greater than the diameter of the polishing pad. During orbital movement, the polishing pad is maintained in a substantially fixed angular orientation relative to the substrate.

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

In another aspect, the chemical mechanical polishing system includes: a substrate support configured to hold the substrate during the polishing 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 generated. The polishing pad has an upper portion fastened to the polishing pad support and a lower portion protruding downward from the upper portion. The upper surface of the upper part adjoins 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, which is smaller than the first lateral dimension.

The implementation plan may include one or more of the following features. The polishing pad support may include a sheet material having a surface spanning the polishing pad, and substantially the entire upper surface of the upper portion of the polishing pad may abut the surface of the sheet material. The adhesive can hold 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 adjoin the annular member, and the remaining portion of the upper surface in the peripheral portion may not contact the polishing pad support. One or more clamping members may hold the peripheral section of the polishing pad on the pad support. The upper portion of the polishing pad may include a flexure section that is more flexible than the section of the polishing pad above the contact surface. The upper portion of the polishing pad may include a polyethylene terephthalate sheet.

A plurality of grooves for slurry transport can be formed on the contact surface of the lower part of the polishing pad. The plurality of grooves may have a smaller depth than the thickness of the lower part. At least some of the plurality of grooves may extend completely across the portion below 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 the polishing pad coupled to the polishing pad support. Can form multiple in the upper surface of the polishing pad Holes, and the plurality of protrusions from the polishing pad support can be fitted into the plurality of holes to align the lower portion with respect 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 cushion carrier and a first lateral dimension. One or more lower portions protrude 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 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.

The implementation plan may include one or more of the following features. At least the lower portion may include a polymer body having a substantially uniform composition and having a plurality of pores distributed within the body. The polishing pad may include a polishing layer, and a lower portion protruding downward may be formed in the polishing layer. The liner may include a backing layer that is softer than the abrasive layer. Grooves 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 convex portion. The abrasive layer may include a flexible lateral section that is thinner than the lateral sections that make up the abrasive region. The lower part may include microporous polyurethane.

In another aspect, a chemical mechanical polishing system includes: a substrate support configured to hold a substantially circular substrate during a polishing operation; a polishing pad support; a polishing pad held by a pad support; and a drive system, via It is configured to generate relative movement between the substrate support and the polishing pad support. The polishing pad has an arc-shaped contact area and is defined by the arc-shaped contact area The center point of the arc is substantially aligned with the center of the substrate held by the substrate support.

The implementation plan may include one or more of the following features. The width of the arc defined by the arc-shaped 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 clamping member can hold the polishing pad on the pad support head. The relative movement between the substrate support and the polishing pad support may be an orbital motion that maintains the polishing pad support in a fixed angle orientation. The relative motion can rotate around the center of the substrate.

In another aspect, the polishing assembly includes a polishing pad support and a polishing pad held by the pad support. The polishing pad support includes an annular member and a recess having an opening facing the substrate. The polishing pad has a polishing surface that contacts the substrate during polishing. The peripheral part of the polishing pad is vertically fixed to the ring member and the remaining part of the polishing pad in the peripheral part is free and vertical. The adjustable pressure is provided on the back surface of the polishing pad by sealing the opening of the polishing pad support facing the substrate by the polishing pad to define a pressurizable chamber.

The implementation plan may include one or more of the following features. The adhesive can fasten the peripheral portion of the polishing pad to the ring member. One or more clamps can hold the peripheral section of the polishing pad on the ring member. The polishing pad support may include a base and a film secured to the base, the volume between the base and the film may define a second pressurizable chamber so that the outer surface of the film provides a second on the back surface of the polishing pad Adjustable pressure. The membrane and the second pressurizable chamber may be configured such that the pressure in the second pressurizable chamber controls the lateral dimension of the load area of the abrasive surface against 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 cushion carrier and a first lateral dimension. One or more lower portions protrude 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 smaller than the first lateral dimension so that the upper portion protrudes through all lateral sides of the lower portion. A plurality of holes are located in the upper surface of the upper portion to receive the protrusion from the cushion carrier. A hole is placed in a section of the upper portion of the polishing pad laterally outward from the lower portion.

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

The advantages of the present invention may include one or more of the following.

Small pads that experience orbital motion can be used to compensate for non-concentric grinding uniformity. The orbital motion can provide an acceptable polishing rate while avoiding overlap of pads with areas not to be polished, thereby improving substrate uniformity. In addition, orbital motion that maintains a fixed orientation of the polishing pad relative to the substrate can provide a more uniform polishing rate across the area being polished compared to rotation.

Making the top portion of the polishing pad fastened to the polishing pad support wider in the lateral direction than the bottom protruding portion in contact with the substrate can increase the available area for the pad to connect to the support (for example, by a pressure sensitive adhesive). This may make the polishing pad less susceptible to delamination during the polishing operation.

A polishing pad having an arc-shaped contact area contacting the substrate can provide an improved polishing rate while maintaining a satisfactory radial resolution of the polishing area.

The alignment feature may ensure that the limited contact area of the polishing pad is placed laterally in a known position relative to the pad support, thereby reducing the possibility of polishing undesired areas of the substrate.

Providing a portion of the deflecting polishing pad can reduce the deflection of the portion of the polishing pad that contacts the surface, thereby improving the likelihood that the polished area matches the operator's expectations.

The grooves in the convex portions of the polishing pad can facilitate the transport of the slurry, and thus can improve the polishing rate.

A portion of the polishing pad that is not in contact with the substrate can be formed from lower cost materials, thereby reducing the total cost of the pad.

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

Overall, non-uniform polishing of the substrate can be reduced, and the resulting flatness and finish of the substrate can be improved.

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

5‧‧‧Contact area/dish geometry

10‧‧‧ substrate

12‧‧‧Surface

20‧‧‧ Orbit radius

22‧‧‧Diameter of contact area

60‧‧‧ port

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‧‧‧Abrasive pad

111‧‧‧Clamping assembly

112‧‧‧Annular clamping ring/arc clamping part

113‧‧‧Actuator

114‧‧‧Flange

116‧‧‧Upper surface

122‧‧‧ chamber

124‧‧‧ port

129‧‧‧Pump

131‧‧‧ retainer

200‧‧‧Abrasive pad

203‧‧‧Abrasive pad

204‧‧‧Abrasive pad

231‧‧‧adhesive

250‧‧‧Abrasive surface

258‧‧‧Abrasive surface

260‧‧‧lower part/bottom part/protruding part

263‧‧‧Bottom part

Section 267‧‧‧

270‧‧‧Part

273‧‧‧Top part

274‧‧‧Part

275‧‧‧Part

Section 285‧‧‧

299‧‧‧slot

300‧‧‧Grinding pad support

311‧‧‧Lower surface

315‧‧‧Grinding pad support

317‧‧‧Dock

320‧‧‧ Wall

325‧‧‧ chamber

327‧‧‧recess

405‧‧‧ film

406‧‧‧Chamber

410‧‧‧Clamping parts

426‧‧‧ chamber

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‧‧‧Abrasive 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‧‧‧Padding holder

922‧‧‧Cam

924‧‧‧Motor output shaft

928‧‧‧recess

990‧‧‧spindle

1032‧‧‧adhesive layer

1052‧‧‧Backrest

1062‧‧‧Grinding layer/upper section

1064‧‧‧Upper section

1066‧‧‧ Lower section

1221‧‧‧Part

1222‧‧‧Lower part/protruding part

1301‧‧‧ contact area

1402‧‧‧recess

1404‧‧‧pin

1406‧‧‧edge

1900‧‧‧Bottom surface

1903‧‧‧ Center

Figure 1 is a schematic cross-sectional side view of a polishing system; Figure 2 is a schematic cross-sectional side view of an implementation of a polishing system including a vacuum chuck to hold a substrate; Figure 3 is a schematic cross-sectional side view of an implementation of a polishing system with a polishing pad that does not include downward convex portions; Figure 4 is an implementation of a polishing system with a polishing pad with upper layers and downward convex portions 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; Figure 5 illustrates a polishing pad moving in a track while maintaining a fixed angle orientation Schematic cross-sectional top view; FIG. 6 is a schematic cross-sectional top view of the polishing pad support and drive column system of the polishing system; FIG. 6A is a schematic cross-sectional top view of the system of FIG. 6 related to the substrate; 6B Fig. 6 is a schematic cross-sectional top view of the system of Fig. 6, rotated by a quarter relative to Fig. 6A; Fig. 7A is a schematic view of a movable polishing pad support connected to a polishing pad having a plurality of clamping members Cross-sectional side view; Figure 7B is a schematic cross-sectional view of an implementation plan of a movable polishing pad support including an internal pressurized space surrounded by an inner film; Figure 8A is a drawing of Figure 7B in a low-pressure state Schematic cross-sectional side view of the movable polishing pad support; Figure 8B is a schematic cross-sectional side view of the movable polishing pad support of Figure 7B in a high-pressure state; Figure 9 is the contact area of the polishing pad Fig. 10A and Fig. 10B are schematic cross-sectional side views of the implementation of the polishing pad; Figure 11 is a schematic cross-sectional side view of another implementation of a movable polishing pad support; Figure 12 is a schematic top view of an implementation of a polishing system having a polishing pad with a curved convex layer, the The arc-shaped convex layer forms a corresponding arc-shaped load region; and FIG. 13 is a schematic cross-sectional side view of an implementation of a polishing system having an arc-shaped polishing surface that undergoes orbital motion.

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

The same element symbol in each drawing indicates the same element.

1 Introduction

Some grinding processes result in uneven thickness across the surface of the substrate. For example, the bulk polishing process can result in under-polished areas on the substrate. To solve this problem, after the block is polished, a "trimming" polishing process may be performed, and the "trimming" polishing process focuses on the substrate portion that is insufficiently polished.

In the bulk polishing process, polishing occurs on the entire front surface of the substrate, even though it may be polished at different rates in different areas of the front surface. Not the entire surface of the substrate can be polished at a given instant in the bulk polishing process. For example, due to the grooves in the polishing pad, a certain portion of the substrate surface may not be in contact with the polishing pad. Nevertheless, during the block polishing process, due to the relative movement between the polishing pad and the substrate, this part is not positioned, so that the entire front surface of the substrate undergoes a certain amount of polishing.

In contrast, in the "trimming" polishing process, the polishing pad can contact less than the entire front surface of the substrate. In addition, the range of motion of the polishing pad relative to the substrate is configured so that during the polishing process, the polishing pad only contacts a local 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 touches the polishing pad and is therefore not subject to polishing. For example, in dressing polishing, the contact area may be substantially smaller than the radius surface of the substrate.

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

Referring to FIG. 1, a polishing apparatus 100 for polishing a local area of a substrate includes a substrate support 105 holding a substrate 10 and a movable polishing pad support 300 holding a polishing pad 200. The polishing pad 200 includes a polishing surface 250 having a diameter smaller than the radius of the substrate 10 being polished.

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

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

Optionally, a vertical actuator (illustrated by 506 and/or 508) may be connected to the substrate support 105 and/or the polishing pad support 300. For example, the substrate support 105 may be connected to a vertically drivable piston, which may raise or lower the substrate support 105.

The polishing apparatus 100 includes a port 60 to distribute polishing liquid 65 (such as abrasive slurry) on the surface 12 of the substrate 10 to be polished. The polishing apparatus 100 may also include a polishing pad adjuster 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 by a robot, for example. The positioning drive system 500 places the polishing pad support 300 and the polishing pad 200 at desired positions on the substrate 10, and actuates vertically The actuator 506 moves the substrate into contact with the polishing pad 200 (or vice versa using the actuator 508). The polishing drive system 500 generates relative movement between the polishing pad support 300 and the substrate support 105 to initiate the polishing of the substrate 10.

During the polishing operation, the positioning drive system 560 may substantially fixedly hold the polishing drive system 500 and the substrate 10 relative to each other. For example, the positioning system may hold the polishing drive system 500 stationary relative to the substrate 10, or may sweep the polishing drive system 500 slowly (compared to the motion provided by the polishing drive system 500 to the substrate 10) across the area to be polished. For example, the instantaneous speed provided by the positioning drive system 500 to the substrate may 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, for example, 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 input based on the environment and desired polishing parameters and control various actuators and drive systems.

For the "dressing" grinding operation, the controller 90 is programmed to control the positioning drive system 560, so that even if the grinding drive system 500 is slowly swept, the movement range of the grinding drive system 500 is limited, so that the process of the dressing grinding process In that, a significant portion of the front surface of the substrate (eg, at least 50%, at least 75%, or at least 90%) never touches the polishing pad and is therefore not subjected to polishing.

2. Grinding system

A. Substrate support

Referring to FIG. 1, the substrate support 105 is a plate-shaped body located below the polishing pad support. The upper surface 116 of the main body provides a load area large enough to accommodate the substrate to be processed. For example, the substrate may 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 (that is, the unpolished surface) and maintains the position of the back surface.

The substrate support 105 has a radius approximately the same as or larger than that of the substrate 10. In some implementations, the substrate support 105 is slightly narrower than the substrate (for example, see FIG. 2), for example, less than 1%-2% of the diameter of the substrate. When placed on the support 105, the edge of the substrate 10 slightly protrudes from the edge of the support 105. This can provide a gap 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 with an end effector with a vacuum chuck can be used to place the substrate on the support. In either case, the substrate support 105 may 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 uses the clamping assembly 111 to maintain the position of the substrate 10 during the grinding operation. In some implementations, the clamping assembly 111 may be a single annular clamping ring 112 that contacts the edge of the top surface of the substrate 10. Alternatively, the clamping assembly 111 may include two arc-shaped clamping members 112 that contact the edges of the top surface on opposite sides of the substrate 10. The clamping member 112 of the clamping assembly 111 can be lowered into contact with the edge of the substrate by one or more actuators 113. The downward force of the clamping piece suppresses the substrate during the grinding operation During the lateral movement. In some implementations, the one or more clamps include a downwardly projecting flange 114 around 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 ports 124 that connect the chamber 122 to the surface 116 of the support substrate 10. In operation, air can be exhausted from the chamber 122 by, for example, a pump 129 to apply suction through the port 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 may be attached to the surface 116 of the support substrate 10 and protrude above the surface. Generally, 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 holder 131 may be a ring-shaped body having a diameter slightly larger than that of the substrate 10. During polishing, friction from the polishing pad 200 may generate lateral forces on the substrate 10. However, the holder 131 restricts 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 may include both a vacuum chuck and a holder.

In addition, although the configuration of the substrate support is illustrated for ease of illustration in conjunction with a pressure sensitive adhesive movable pad support configuration, these configurations may be any of the embodiments of the pad support head and/or drive system described below Use them together.

B. Grinding pad

Referring to FIG. 1, the polishing pad 200 has a polishing surface 250 that makes contact with the substrate 10 in a contact area (also referred to as a load area) during polishing. The abrasive surface 250 may have a diameter smaller than the radius of the substrate 10. For example, the diameter of the abrasive surface may be about 5%-10% of the diameter of the substrate. For example, for wafers with diameters ranging from 200 mm to 300 mm, the diameter of the grinding surface may be between 10 mm and 30 mm. The smaller abrasive surface provides more accuracy but lower yield.

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

In some implementations, for example, as shown in FIG. 3, the entire polishing pad (e.g., measured at the outer edge of the pad) has a diameter smaller than the radius of the substrate 10. For example, the diameter of the polishing pad may be about 5%-10% of the diameter of the substrate.

In the example in FIG. 1, a polishing pad 200 is placed above 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 the protruding portion from the wider upper portion 270. The bottom surface 250 of the protruding portion 260 contacts the substrate during the grinding operation and provides a grinding surface.

In the example in FIG. 1, the pressure-sensitive adhesive 231 is used to couple the movable pad support 300 to the upper portion 270 of the polishing pad 200. 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 polishing 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 can improve the bonding strength between the pad 200 and the pad support, and reduce the risk of delamination of the polishing pad during polishing.

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

Referring to FIG. 5, the contact area 5 of the polishing pad may be a dish-shaped geometry 5 formed by a dish-shaped bottom protrusion of the polishing pad.

Referring to FIGS. 9A and 9B, the contact area 901 of the polishing pad 110 in contact with the substrate 10 may be an arc-shaped contact area 901 formed by the arc-shaped protruding portion 290 of the polishing pad.

Referring to FIG. 1, in some implementations, the diameter of the upper portion 270 of the polishing pad 200 may be smaller than the diameter of the substrate 10.

Referring to FIG. 4, in some implementations, the diameter of the portion 274 above the polishing pad 204 may be larger than the diameter of the substrate 10.

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

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

Referring to FIG. 10A, in some implementations, the polishing pad may include two or more layers with different compositions, and the upper portion 1221 of the polishing pad 200 may include a backing layer 1052 and a section above the polishing layer 1062 1064 both. Therefore, the abrasive layer 1062 includes both the lower section 1066 and the upper section 1062 providing the protruding portion 1222, where the upper section 1064 is wider than the lower section 1066.

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

In any implementation shown in FIG. 10A or FIG. 10B, the polishing layer 1062 may be composed of a single layer of a uniform composition. For example, in any of the implementation schemes shown in FIG. 10A or FIG. 10B, the portion of the liner that contacts the substrate may have a conventional material, such as a microporous polymer, such as polyurethane.

Referring to FIG. 10A, the backing layer 1052 may be relatively soft to allow better flexibility of the polishing pad when polishing uneven substrate surface spots. The abrasive layer 1064 may be hard polyurethane.

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

Referring to FIG. 11, in some implementations, the polishing pad 205 may include an upper part 275 and a lower part 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. The lateral side section 285 flexes in response to the pressure on the thicker section 267. The thicker section 267 may have a pad thickness of about 2 mm in the abrasive area, which is similar to a large-size pad. The thickness of the pad in the flexure lateral section 285 may be about 0.5 mm.

In some implementations, the bottom surface 250 of the lower portion of the polishing pad 200 may include grooves to allow slurry to be transported during the polishing operation. The groove 299 may be shallower than the depth of the lower portion 260 (for example, see FIG. 11). However, in some implementations, the lower part does not include slots. If the polishing pad includes a groove, the groove 299 may extend completely across the lateral width of the lower portion 260. In addition, the groove may be shallower than the vertical thickness of the lower portion 260, that is, the groove partially passes through the lower portion 260 in a vertical manner but not completely.

Referring to FIG. 9, the bottom surface 1900 of the polishing pad 200 may be an arc-shaped area. If the polishing pad includes a groove, the groove 299 may extend completely across the lateral width of the arc-shaped area. The grooves 299 may be spaced at uniform intervals along the length of the arc-shaped area. Each groove 299 may extend along a radius that passes through the center of the groove and the arc-shaped area 1903, or each groove 299 may be positioned at an angle (eg, 45°) with respect to the radius.

Referring to FIG. 14, in some implementations, the polishing pad 200 includes alignment features that are mated with matching features on the pad support 300 to ensure the polishing pad 200 and the lower portion that provides the contact area 250 260 is in a known lateral position relative to the pad support 300.

For example, the polishing pad 200 may include a recess 1402 formed in the back surface of the polishing pad 200. The recess 1402 can be machine-drilled in a known position in the polishing pad relative to the contact area 250. A recess 1402 may be placed in the thin flange or outer lateral portion 285 of the upper portion 270 of the polishing pad 200. The recess may extend partially or completely through the polishing pad. The pad support 300 may include pins 1404 (e.g., protruding downward from the plate), the pins fit into the recess 1402.

As another example, after the contact area 250 is defined on the polishing pad 200, at least some edges 1406 of the polishing pad 200 may be processed. The pad support 300 may include a recess 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 contacting the substrate may be formed of high-quality materials, such as satisfying rigidity, porosity and High-precision specifications of the material. However, other parts of the polishing pad that are not in contact with the substrate need not meet such high-precision specifications, and therefore can be formed of lower cost materials. This can reduce the total cost of the liner.

C. Drive system and track movement of the pad

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

Referring to FIG. 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 may be about 5%-50% of the diameter of the contact area (eg, 5%-20%). For a 20mm to 30mm diameter contact area, the track radius can be 1mm to 6mm. This achieves a more uniform speed distribution in the load area 5. The polishing pad can run in orbit at a rate of 1000 to 5000 revolutions per minute ("rpm").

Referring to FIG. 6, the drive train may include a mechanical system base 910 that uses a single actuator 915 to achieve orbital motion. The motor output shaft 924 is coupled to the cam 922. The cam 922 extends into the recess 928 in the polishing pad holder 920. During the grinding operation, the motor output shaft 924 rotates about the rotating shaft 990, causing the cam 922 to rotate the grinding pad holder 920. A plurality of anti-rotation links 912 extend from the mechanical system base 910 to the upper portion of the polishing pad holder 920 to prevent the pad holder 920 from rotating. Anti-rotation combined with the movement of cam 922 The connecting rod 912 enables the orbital movement of the polishing pad support, wherein the angular orientation of the polishing pad holder 920 has not changed during the polishing 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 polishing operation. As the central motor output shaft 620 rotates, the cam 625 combined with the anti-rotation links 630 translate the rotational motion into the orbital motion of the polishing pad 610, which connects the upper mechanical system base to the polishing pad support . This achieves a more uniform speed distribution than simple 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 may include two linear actuators that are 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 the desired position on the substrate. For grinding, the controller may cause the actuator to move the pad support in orbital motion, for example, by applying a phase-shifted sinusoidal signal to the two actuators.

Referring to FIG. 1, in some implementations, the grinding drive system 500 may include two rotary actuators. For example, the polishing pad support may be suspended from the rotary actuator 508, and then the rotary actuator is 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 in orbital motion. The first rotary actuator 508, for example, rotates in the opposite direction to the second rotary actuator 509 but at the same rotational speed to counteract the rotary motion so that the polishing pad assembly is maintained 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 polishing driving system 500.

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

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

In the example in FIG. 7A, a pad support 300 is shown, which 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 may cover the recess 327 to define a pressurizable chamber 426. By pumping fluid into and out of the chamber 426, the downward pressure of the polishing pad 200 on the substrate 10 can be adjusted.

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

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

Referring to FIG. 12, in some implementation solutions, the contact area 1301 of the polishing pad 20 may be an arc-shaped area. For example, the protruding portion may be arc-shaped. The drive system 500 can rotate the arc around the center 1302 of the substrate 10.

Referring to FIG. 13, in some embodiments, the contact area 901 of the polishing pad 200 may be an arc-shaped area that undergoes orbital motion relative to the substrate 10.

3. Conclusion

The point size of the non-uniformity on the substrate will indicate the ideal size of the contact area during grinding at that point. If the contact area is too large, the correction of insufficient polishing of some areas on the substrate may lead to excessive polishing of other areas. On the other hand, if the contact area is too small, the liner will need to be moved across the substrate to cover the under-polished area, thereby reducing throughput.

In the substrate processing operation, the substrate may first undergo a bulk polishing process, where the polishing is performed on the entire front surface of the substrate. As the case may be, after the block grinding operation, the non-uniformity of the substrate may be measured, for example, in a production line or at an independent measuring station. The substrate can then be transported to the grinding apparatus 100 and undergo a finishing grinding process. The control of the area to be polished at the polishing equipment can be based on the identification of the under-polished area of the substrate, which comes from historical data (for example, thickness measurements generated during quality assessment) or from substrate measurements within the production line or at independent measurement stations .

The entire grinding system can be arranged with the front surface of the substrate placed vertically or face down (relative to gravity). However, the advantage of having the front surface of the substrate face up is that this allows the slurry to be distributed on the surface of the substrate. Due to the larger size of the substrate relative to the polishing surface of the polishing pad, this can improve slurry retention and thus reduce slurry usage.

Numerous embodiments of the present invention have been described. Nevertheless, it should be understood that various modifications can be made without departing from the spirit and scope of the invention. For example, in some embodiments, the substrate support may include its own actuators that can move the substrate into the appropriate position relative to the polishing pad. As another example, although 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 the substantially fixed position and the substrate is moved in the track. In this case, the polishing drive system may be a similar drive system, but coupled to the substrate support instead of the polishing pad support. Although a substantially circular substrate is used, this is not necessary and the support and/or polishing pad It may be other shapes such as a rectangle (in this case, the discussion of "radius" or "diameter" will generally be adapted to the lateral dimension along the major axis).

Therefore, other embodiments are within the scope of the following patent applications.

10‧‧‧ substrate

12‧‧‧Surface

60‧‧‧ port

65‧‧‧Slurry

91‧‧‧Central Processing Unit

92‧‧‧Memory

93‧‧‧Support circuit

99‧‧‧Controller

100‧‧‧Grinding equipment

105‧‧‧ substrate support

111‧‧‧Clamping assembly

112‧‧‧Annular clamping ring/arc clamping part

113‧‧‧Actuator

114‧‧‧Flange

116‧‧‧Upper surface

200‧‧‧Abrasive pad

231‧‧‧adhesive

250‧‧‧Abrasive surface

260‧‧‧lower part/bottom part/protruding part

270‧‧‧Part

300‧‧‧Grinding 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 (25)

A chemical mechanical polishing system includes: a substrate support configured to hold a substrate at a substantially fixed angle orientation during a polishing 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 movable pad support and grind in a track motion while the polishing pad is in contact with one of the upper surfaces of the substrate Pad, the orbital movement has a track radius no greater than one of the diameters of the polishing pad and maintains the polishing pad at a fixed angle orientation relative to the substrate. The system of claim 1, further comprising the polishing pad, wherein the polishing pad has a contact area that contacts the substrate. The system of claim 2, wherein a diameter of the contact area is between about 1% and 10% of the diameter of the substrate. The system of claim 3, wherein the orbital radius is between about 5% and 50% of the diameter of the contact area. The system of claim 2, wherein the polishing pad includes: an upper portion having an outer edge for attaching a pad carrier, the upper portion having a first lateral dimension; and one or more A plurality of lower portions, the one or more lower portions protrude downward from the upper portion, and a bottom surface of one of the one or more lower portions is provided at During the chemical mechanical polishing, the contact surface contacting the substrate, each lower portion has a second lateral dimension smaller than the first lateral dimension, and wherein the total surface area from one of the contact surfaces of the one or more lower portions is not More than 10% of the surface area of one of the upper surfaces. The system of claim 5, wherein at least the lower portion is a polymer body having a substantially uniform composition and having a plurality of holes distributed in the body. The system of claim 5, further comprising a groove for slurry transport on the bottom surface of the one or more lower portions. The system of claim 5, wherein the one or more lower portions are composed of a single convex portion. The system of claim 5, wherein the lower part is a microporous polyurethane. The system of claim 2, wherein the polishing pad includes a protruding portion from a layer, and a bottom surface of the protruding portion provides the contact area. The system of claim 2, comprising at least one of a pressure-sensitive adhesive or a clamping member, the pressure-sensitive adhesive or at least one of the clamping member holding the polishing pad on the pad support . The system of claim 2, wherein the contact area is one of dish-shaped or arc-shaped. The system according to claim 1, wherein the drive system Contains a recess in the movable pad support, a rotatable cam extending into the recess, and a motor connected to the cam. The system of claim 13, further comprising link sets that couple the movable cushion support to a fixed support to prevent rotation of the movable cushion support. The system of claim 1 includes a positioning drive system to laterally move the movable pad support across the substrate. The system of claim 15, wherein the positioning drive system includes two linear actuators configured to move the movable pad support in two vertical directions. The system of claim 1, wherein the substrate support comprises at least one of a vacuum chuck, a clamping member, or a lateral holder. The system of claim 1, wherein the drive system is configured to run the polishing pad in a track at a rate of 1,000 to 5,000 revolutions per minute. A chemical mechanical polishing method including the following steps: bringing a polishing pad into contact with a substrate in a contact area, the contact area having a diameter no greater than a radius of the substrate; in the contact area of the polishing pad The relative movement between the polishing pad and the substrate is generated while contacting one of the upper surfaces of the substrate, the phase Pairing motion includes an orbital motion having an orbital radius no greater than a diameter of the polishing pad; and during the orbital motion, maintaining the polishing pad at a substantially fixed angular orientation relative to the substrate. The method of claim 19, comprising the steps of: holding the substrate in a fixed lateral position during the orbital movement. The method of claim 20, further comprising the step of: during the orbital motion, sweeping the polishing pad laterally across the substrate at a speed not greater than about 5% of an instantaneous speed of the orbital motion. A chemical mechanical polishing system includes: a substrate support configured to hold a substrate during a polishing operation; a polishing pad support; a polishing pad held by the polishing pad support, the polishing pad having a fastening to An upper portion of the polishing pad support and a lower portion protruding downward from the upper portion, wherein an upper surface of the upper portion adjoins the polishing pad support, and a bottom surface of the lower portion provides contact with the during polishing 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 having a first lateral dimension and the lower portion having a second lateral dimension, the second lateral dimension being greater than the The first horizontal dimension is small; A pressure chamber formed by an internal chamber of the polishing pad support, the chamber having an opening facing the substrate, and the opening is sealed by the polishing pad coupled to the polishing pad support And a drive system configured to generate relative movement between the substrate support and the polishing pad support. The chemical mechanical polishing system of claim 22, wherein the polishing pad support includes an annular member, a peripheral portion of an upper surface of the upper portion of the polishing pad adjoins the annular member, and the The remaining part of one of the upper surfaces does not contact the polishing pad support. The chemical mechanical polishing system of claim 23, wherein the upper portion of the polishing pad includes a flexure section that is larger than a section of the polishing pad above the contact surface flexibility. The chemical mechanical polishing system according to claim 22, 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 fitted into the plurality of holes To align the lower portion relative to the polishing pad support.

Images