Elastic film, polishing head, and polishing method

Abstract

To provide an elastic film capable of improving elasticity.SOLUTION: An elastic film 100 comprises a pressing portion 101, and a partition wall 102 having a bulging structure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an elastic membrane, a polishing head, and a polishing method. [Background technology]

[0002] The precision required for each process in the manufacturing of modern semiconductor devices has already reached the order of several nm, and chemical mechanical polishing (CMP) is no exception. In addition, with the increasing integration density of semiconductor integrated circuits, miniaturization and multi-layering are accelerating.

[0003] Therefore, in order to realize these miniaturizations and multi-layerings, it is necessary to limit the variation in film thickness after CMP polishing to the order of several nm over the entire surface of the wafer.

[0004] Factors that cause variations in residual film thickness include variations in film formation on the wafer. For example, the process of forming a film on the wafer is carried out using various film formation techniques such as plating, chemical vapor deposition (CVD), and physical vapor deposition (PVD). With these film formation techniques, the film may not be formed uniformly over the entire surface of the wafer. In recent years, variations in the thickness and shape of the wafer itself can also cause these variations, and there is a demand for planarizing such wafers using the CMP process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-223322 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional polishing heads can independently change the pressure in the radial direction of the wafer, so it is possible to control the film thickness profile in the radial direction of the wafer. However, since the pressure chambers are arranged concentrically, it is not possible to control the pressure in the circumferential direction of the wafer, and therefore it is not possible to control the film thickness profile in the circumferential direction. To address this issue, a method of dividing the pressure chambers in the circumferential direction can be considered.

[0007] When pressure is applied to a pressure chamber formed by an elastic membrane made of an elastic material commonly used in CMP devices, the elastic membrane expands and adheres to the wafer. With this configuration, the elastic membrane can transmit the pressure in the pressure chamber evenly to the wafer.

[0008] However, the elastic membrane has many partitions for forming the divided pressure chambers, and such an elastic membrane is difficult to stretch, particularly in the vicinity of the partitions, and there is a risk that the pressure in the pressure chambers cannot be uniformly transmitted to the wafer.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an elastic film and a polishing head that can improve elasticity. An object of the present invention is to provide a polishing method using an elastic film that can improve the stretchability. [Means for solving the problem]

[0010] In one aspect, there is provided an elastic membrane applicable to a polishing head for polishing a substrate, the elastic membrane having a pressing portion for pressing the substrate and a partition wall having a bulging structure forming a pressure chamber for applying a pressing force to the pressing portion.

[0011] In one embodiment, the partition has a first wall portion and a second wall portion that form the bulge structure, and the first wall portion and the second wall portion have wide portions spaced apart from each other and clamp portions connected to the wide portions and adjacent to each other. In one embodiment, the partition has a first wall portion and a second wall portion having a V-shaped cross-sectional shape that are adjacent to each other toward the pressing portion, and the first wall portion and the second wall portion are connected to each other at the pressing portion. In one embodiment, the partition has a first wall portion, a second wall portion and a third wall portion having a Y-shaped cross-sectional shape, and the third wall portion is connected to the first wall portion and the second wall portion and extends from a connection portion between the first wall portion and the second wall portion toward the pressing portion.

[0012] In one embodiment, the partition has a first pressure chamber and a second pressure chamber arranged on either side of the pressure chamber, and the pressure chamber is arranged above the first pressure chamber and the second pressure chamber. In one embodiment, the elastic membrane has a peripheral wall that defines its outer shape, and the partition has a peripheral side wall portion that is disposed adjacent to the peripheral wall and extends at an angle relative to the pressing portion.

[0013] In one aspect, a polishing head is provided, comprising the above-described elastic membrane and a head body that holds the elastic membrane.

[0014] In one embodiment, the head body includes a partition holder that holds the partition, and at least a portion of the partition holder is disposed in the pressure chamber. In one embodiment, the polishing head has a widthwise gap formed between the partition and the partition holder.

[0015] In one aspect, a polishing method is provided in which a substrate is held by an elastic membrane that presses the substrate, and while the substrate is held, a fluid is supplied to a pressure chamber formed by a pressing portion that presses the substrate to press the substrate against a polishing pad, and a fluid is supplied to a pressure chamber formed by a partition having a bulge structure to apply a pressing force to the pressing portion.

[0016] In one embodiment, the step of holding the substrate includes the step of supplying a fluid to the pressure chamber and forming a vacuum in the pressure chamber to form an adsorption space below the pressing portion and adsorb the substrate. In one embodiment, the polishing method includes a step of, after polishing of the substrate is completed, forming a vacuum in the pressure chamber and supplying a fluid to the pressure chamber, thereby detaching the substrate from the elastic film. In one embodiment, the partition has a first wall portion and a second wall portion that form the bulge structure, and the first wall portion and the second wall portion have wide portions spaced apart from each other and clamp portions connected to the wide portions and adjacent to each other.

[0017] In one embodiment, the partition has a first wall portion and a second wall portion having a V-shaped cross-sectional shape that are adjacent to each other toward the pressing portion, and the first wall portion and the second wall portion are connected to each other at the pressing portion. In one embodiment, the partition has a first wall portion, a second wall portion and a third wall portion having a Y-shaped cross-sectional shape, and the third wall portion is connected to the first wall portion and the second wall portion and extends from a connection portion between the first wall portion and the second wall portion toward the pressing portion. In one embodiment, the elastic membrane has a peripheral wall that defines its outer shape, and the partition has a peripheral side wall portion that is disposed adjacent to the peripheral wall and extends at an angle relative to the pressing portion. Effect of the Invention

[0018] The partition has a bulging structure that forms a pressure chamber, and this structure can improve the elasticity of the elastic membrane, particularly the elasticity of the pressed portion. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram illustrating an embodiment of a polishing apparatus. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing one embodiment of a polishing head. [Diagram 3]FIG. 2 is a plan view of one embodiment of an elastic membrane. [Figure 4] FIG. 4 is a partial cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 4 is a partial cross-sectional view taken along line BB in FIG. [Figure 6] FIG. 13 illustrates another embodiment of the elastic membrane. [Figure 7] FIG. 13 illustrates another embodiment of the elastic membrane. [Figure 8] Figure 8(a) is a diagram showing an example of a partition wall attached to a partition wall holder, Figure 8(b) is a diagram showing another example of a partition wall attached to a partition wall holder, and Figure 8(c) is a diagram showing a tilted state of the partition wall attached to the partition wall holder. [Figure 9] FIG. 13 shows another embodiment of the partition wall. [Figure 10] FIG. 10(a) is a diagram showing one embodiment of the peripheral wall of the elastic membrane, and FIG. 10(b) is a diagram showing another embodiment of the peripheral wall. [Figure 11] 11(a) and 11(b) are diagrams showing the operation of the polishing head to suction and hold the wafer. [Figure 12] FIG. 13 illustrates another embodiment of the elastic membrane. [Figure 13] 13A and 13B are diagrams showing the operation of the polishing head releasing the wafer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals, and duplicated descriptions will be omitted. In the multiple embodiments described below, the configuration of one embodiment that is not particularly described is the same as the other embodiments, so duplicated descriptions will be omitted.

[0021] Fig. 1 is a schematic diagram showing one embodiment of a polishing apparatus. As shown in Fig. 1, the polishing apparatus PA includes a polishing head PH that holds and rotates a wafer W, which is an example of a substrate, a polishing table 2 that supports a polishing pad 1, a polishing liquid supply nozzle 3 that supplies a polishing liquid (slurry) onto the polishing surface 1a of the polishing pad 1, and a dresser 41 that dresses the polishing surface 1a of the polishing pad 1.

[0022] The polishing table 2 rotates about its central axis CL1. The polishing head PH rotates about its central axis CL2. The polishing table 2 and the polishing head PH rotate in the same direction (see FIG. 1), and in this state, the polishing head PH presses the wafer W against the polishing surface 1a of the polishing pad 1. The polishing liquid supply nozzle 3 supplies the polishing liquid onto the polishing surface 1a, and the wafer W is polished by sliding contact with the polishing pad 1 in the presence of the polishing liquid.

[0023] The polishing apparatus PA includes a head shaft 16 connected to the polishing head PH, a vertical movement mechanism 5 for moving the polishing head PH up and down via the head shaft 16, a rotation mechanism 6 for rotating the polishing head PH via the head shaft 16, and a swing arm 14 on which the vertical movement mechanism 5 and the rotation mechanism 6 are mounted.

[0024] The vertical movement mechanism 5 and the rotation mechanism 6 are supported by a support base 14a of the swing arm 14. The vertical movement mechanism 5 includes a vertical movement motor 30 and a connecting member 31 that connects the vertical movement motor 30 and the head shaft 16. The vertical movement motor 30 is, for example, a precision motor such as a servo motor. When driven, the vertical movement motor 30 moves the head shaft 16 up and down via the connecting member 31. The polishing head PH moves up and down together with the head shaft 16.

[0025] The rotation mechanism 6 includes a rotation motor 22, a rotary cylinder 23 attached to the head shaft 16 via a key (not shown), and a timing belt 24 stretched between the rotation motor 22 and the rotary cylinder 23. The rotation motor 22 is, for example, a precision motor such as a servo motor.

[0026] The rotating cylinder 23 is rotatably supported by bearings 25A and 25B mounted on the support base 14a. The rotating motor 22 rotates the rotating cylinder 23 via a timing belt 24. The rotating cylinder 23 transmits the rotational force to the head shaft 16, causing the head shaft 16 to rotate. The polishing head PH rotates together with the head shaft 16.

[0027] The head shaft 16 is inserted into the rotating cylinder 23 so as to be movable up and down. Therefore, the rotational force acting on the rotating cylinder 23 is transmitted to the head shaft 16, while the vertical force acting on the head shaft 16 is not transmitted to the rotating cylinder 23. A rotary joint 32 is attached to the upper end of the head shaft 16.

[0028] The polishing apparatus PA includes a swing mechanism 7 that swings the swing arm 14. The swing mechanism 7 includes an arm shaft 12 that supports the swing arm 14, and a swing motor 20 that swings the swing arm 14 via the arm shaft 12. The swing motor 20 is, for example, a precision motor such as a servo motor. The swing motor 20 swings the swing arm 14 via the arm shaft 12 by being driven by the swing motor 20. In this way, the swing arm 14 is configured to be rotatable around the arm shaft 12.

[0029] The polishing apparatus PA includes a plurality of fluid lines 33, 77, 88 extending to the polishing head PH through the rotary joint 32. The plurality of fluid lines 33, 77, 88 are connected to a pressure regulator 36. The pressure regulator 36 is configured to regulate the pressure of the fluid supplied to the polishing head PH through the plurality of fluid lines 33, 77, 88. Examples of the fluid supplied include nitrogen gas and clean dry air.

[0030] The polishing apparatus PA includes a control device 10 that controls the operations of the components of the polishing apparatus PA (e.g., the polishing table 2, the polishing head PH, the dresser 41, the polishing liquid supply nozzle 3, etc.) The control device 10 includes a memory unit 10a that stores a program, and a calculation unit 10b that executes calculations according to instructions included in the program.

[0031] The storage unit 10a includes a main storage device such as a RAM, and an auxiliary storage device such as a hard disk drive (HDD), a solid state drive (SSD), etc. Examples of the calculation unit 10b include a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit).

[0032] The control device 10 is composed of at least one computer. The computer may be one server or multiple servers. The control device 10 may be an edge server, a cloud server connected to a communication network such as the Internet or a local area network, or a fog computing device (gateway, fog server, router, etc.) installed in the network. The control device 10 may be multiple servers connected by a communication network such as the Internet or a local area network. For example, the control device 10 may be a combination of an edge server and a cloud server.

[0033] The control device 10 is electrically connected to the pressure regulator 36. Thus, the control device 10 is configured to operate the pressure regulator 36 to regulate the pressure of the fluid supplied to the polishing head PH (particularly, the elastic membrane 100) through the fluid lines 33, 77, and 88.

[0034] The polishing apparatus PA includes a film thickness sensor ES disposed below the polishing table 2. The film thickness sensor ES is configured to detect a film thickness signal that changes in accordance with the film thickness of the wafer W. Examples of the film thickness sensor ES include an optical sensor or an eddy current sensor.

[0035] In one embodiment, the film thickness sensor ES may be embedded in the polishing table 2. The film thickness sensor ES is electrically connected to the control device 10 and configured to send a film thickness signal detected by the film thickness sensor ES to the control device 10. The control device 10 measures the film thickness of the wafer W based on the film thickness signal, and terminates polishing of the wafer W based on the film thickness of the wafer W.

[0036] The process of polishing the wafer W is as follows. While rotating the polishing table 2 and the polishing head PH, a polishing liquid is supplied from the polishing liquid supply nozzle 3 onto the polishing surface 1a of the polishing pad 1. With the polishing liquid present on the polishing surface 1a, the polishing head PH presses the wafer W against the polishing surface 1a while rotating the wafer W. As a result, the surface of the wafer W is polished by the mechanical action of the abrasive grains contained in the polishing liquid and the chemical action of the polishing liquid.

[0037] During polishing of the wafer W, the control device 10 acquires a film thickness signal detected by the film thickness sensor ES, and measures the film thickness of the wafer W based on the acquired polishing signal. Based on the measured film thickness, the control device 10 controls the polishing operation of the wafer W. When the film thickness of the wafer W reaches a target film thickness, the control device 10 operates the polishing head PH to end polishing of the wafer W.

[0038] Generally, an elastic membrane has many partitions for forming divided pressure chambers. Such an elastic membrane is difficult to stretch, especially near the partitions, and may not be able to uniformly transmit the pressure in the pressure chamber to the wafer W. As a result, the polishing head PH may not be able to apply an appropriate pressing force to the wafer W, which may adversely affect the uniformity of the wafer W. Therefore, in this embodiment, the elastic membrane 100 has a structure that can improve the stretchability. The structure of the elastic membrane 100 will be described below with reference to the drawings.

[0039] 2 is an enlarged cross-sectional view showing one embodiment of the polishing head PH. As shown in FIG. 2, the polishing head PH includes a head body 49, a retainer ring mechanism 57 for preventing the wafer W from jumping out, and an elastic membrane 100 disposed below the head body 49 and for holding the wafer W.

[0040] The head main body 49 includes a circular flange portion 53 connected to the head shaft 16, a spacer 70 attached to the underside of the flange portion 53, and a carrier (base plate) 71 attached to the underside of the spacer 70. The carrier 71 is connected to the flange portion 53 via the spacer 70, and the flange portion 53, the spacer 70, and the carrier 71 rotate together and move up and down.

[0041] The retainer ring mechanism 57 includes a retainer ring 75 that surrounds the wafer W, and a retainer ring pressing mechanism 56 that is disposed above the retainer ring 75. The retainer ring 75 is disposed so as to surround the peripheral portion of the wafer W, and is capable of contacting the polishing surface 1a of the polishing pad 1. The retainer ring 75 prevents the wafer W from jumping out of the polishing head PH during polishing of the wafer W.

[0042] The retainer ring 75 is configured to be movable up and down independently of the flange portion 53 by the operation of the retainer ring pressing mechanism 56. The retainer ring pressing mechanism 56 includes an annular rolling diaphragm 76 and a fluid line 77 that supplies a fluid (e.g., air) to the rolling diaphragm 76.

[0043] The rolling diaphragm 76 has a retainer ring pressure chamber SP formed therein. The fluid line 77 passes through the flange portion 53 and communicates with the retainer ring pressure chamber SP. Therefore, when fluid is supplied to the retainer ring pressure chamber SP through the fluid line 77, the rolling diaphragm 76 presses down on the retainer ring 75. As the retainer ring 75 is pressed down, it is pressed against the polishing surface 1a of the polishing pad 1.

[0044] On the other hand, by forming a vacuum in the retaining ring pressure chamber SP through the fluid line 77, the rolling diaphragm 76 lifts the retaining ring 75. The retaining ring pressure chamber SP is also connected to an atmosphere release mechanism (not shown). Therefore, it is possible to release the retaining ring pressure chamber SP to the atmosphere.

[0045] Fig. 3 is a plan view showing one embodiment of the elastic membrane. Fig. 4 is a partial cross-sectional view taken along line AA in Fig. 3. Fig. 5 is a partial cross-sectional view taken along line BB in Fig. 3. The elastic membrane 100 is made of a flexible rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, or silicone rubber.

[0046] The elastic membrane 100 has a planar pressing portion 101 that presses the wafer W, a plurality of partition walls 102 that extend from the pressing portion 101 toward the head body 49, and a peripheral wall 103 that is connected to the outermost partition wall 102 of the plurality of partition walls 102 and that constitutes the outer shape of the elastic membrane 100. The pressing portion 101, the partition walls 102, and the peripheral wall 103 are integrally molded members.

[0047] The elastic membrane 100 has a pressure chamber A1 formed in the center of the elastic membrane 100 by a pressing portion 101, multiple partitions 102 and a peripheral wall 103, and multiple pressure chambers A2 to A5 divided along the radial and circumferential directions of the wafer W (i.e., the polishing head PH).

[0048] The pressure chamber A1 is disposed along the central axis CL2 of the head shaft 16. In the embodiment shown in Fig. 3, the pressure chamber A1 has a circular shape when viewed from the head shaft 16 side (i.e., from above). In one embodiment, the pressure chamber A1 may have a polygonal shape.

[0049] Fig. 6 is a diagram showing another embodiment of the elastic membrane. As shown in Fig. 6, the pressure chamber A1 may have a plurality of pressure chambers A1-A, A1-B, A1-C, and A1-D each having a sector shape when viewed from above. These pressure chambers A1-A to A1-D are arranged at equal intervals along the circumferential direction of the elastic membrane 100.

[0050] As shown in Fig. 6 (and Fig. 3), pressure chambers A2 to A5 are disposed around pressure chamber A1 and are arranged at equal intervals along the circumferential direction of elastic membrane 100. More specifically, pressure chamber A2 is made up of multiple pressure chambers A2-A, A2-B, A2-C, and A2-D surrounding pressure chamber A1. Pressure chamber A3 is made up of multiple pressure chambers A3-A, A3-B, A3-C, and A3-D surrounding pressure chamber A2.

[0051] Similarly, pressure chamber A4 is made up of multiple pressure chambers A4-A, A4-B, A4-C, and A4-D surrounding pressure chamber A3. Pressure chamber A5 is made up of multiple pressure chambers A5-A, A5-B, A5-C, and A5-D surrounding pressure chamber A4.

[0052] Fig. 7 is a diagram showing another embodiment of the elastic membrane. In the embodiment shown in Fig. 6, the multiple pressure chambers constituting the pressure chambers A2 to A5 surrounding the pressure chamber A1 are linearly (i.e., on a straight line) arranged along the radial direction of the elastic membrane 100. In one embodiment, as shown in Fig. 7, the multiple pressure chambers constituting the pressure chambers A2 to A5 arranged along the radial direction of the elastic membrane 100 may be arranged offset by a predetermined rotation angle (a rotation angle of 45 degrees in the embodiment shown in Fig. 7) along the circumferential direction of the elastic membrane 100.

[0053] The fluid line 33 penetrates the head main body 49 (more specifically, the flange portion 53, the spacer 70, and the carrier 71) and communicates with each of the pressure chambers A1 to A5 (see FIG. 2). Therefore, the control device 10 can operate the pressure adjustment device 36 to individually control the pressure of the fluid supplied to the pressure chambers A1 to A5 through the fluid line 33.

[0054] Each of the pressure chambers A1 to A5 is connected to a vacuum line (not shown). The control device 10 is configured to control the operation of a vacuum pump (not shown) connected to the vacuum line. Therefore, the control device 10 can create a vacuum in each of the pressure chambers A1 to A5 by operating the vacuum pump.

[0055] Each of the pressure chambers A1 to A5 is also connected to an atmosphere opening mechanism (not shown), and therefore each of the pressure chambers A1 to A5 can be opened to the atmosphere.

[0056] Since the plurality of partition walls 102 basically have the same structure, the structure of a single partition wall 102 will be described below with reference to FIG.

[0057] 5, the partition wall 102 has a bulging structure that bulges in a direction away from the pressing region 101. The partition wall 102 having such a bulging structure forms a pressurizing chamber MSP for applying a pressing force to the pressing region 101.

[0058] The pressure chambers MSP are formed between adjacent pressure chambers among the pressure chambers A1 to A5 along the radial direction of the elastic membrane 100. More specifically, the multiple pressure chambers MSP are arranged between the pressure chambers A1 and A2, between the pressure chambers A2 and A3, between the pressure chambers A3 and A4, and between the pressure chambers A4 and A5. The pressure chamber MSP arranged on the outermost side of the elastic membrane 100 is adjacent to the pressure chamber MSP arranged between the pressure chambers A4 and A5.

[0059] In this manner, among the pressure chambers A1 to A5, the pressure chambers adjacent to each other are disposed on both sides of the pressure chamber MSP. The pressure chamber MSP is formed above the pressing portion 101, that is, above the pressure chambers A1 to A5.

[0060] The polishing apparatus PA includes a fluid line 88 extending to the pressurized chamber MSP through the rotary joint 32 (see FIG. 2). The fluid line 88 is connected to the pressure regulator 36. Therefore, the control device 10 can individually control the pressure of the fluid supplied to the pressurized chamber MSP through the fluid line 88 by operating the pressure regulator 36.

[0061] The pressurized chamber MSP is connected to a vacuum line (not shown). The control device 10 is configured to control the operation of a vacuum pump (not shown) connected to the vacuum line. Therefore, the control device 10 can form a vacuum in the pressurized chamber MSP. The pressurized chamber MSP is also connected to an atmosphere release mechanism (not shown). Therefore, the pressurized chamber MSP can be released to the atmosphere.

[0062] Figure 8(a) is a diagram showing an example of a partition wall attached to a partition wall holder, Figure 8(b) is a diagram showing another example of a partition wall attached to a partition wall holder, and Figure 8(c) is a diagram showing a tilted state of the partition wall attached to the partition wall holder.

[0063] As shown in Fig. 8(a) (and Fig. 2), the carrier 71 is provided with partition holders 110, the number of which corresponds to the number of partitions 102. The partition holders 110 are fixed to the lower surface of the carrier 71, and have communication holes 110a connected to the fluid line 88 (and the vacuum line). Therefore, the pressurized chamber MSP communicates with the fluid line 88 through the communication holes 110a of the partition holders 110.

[0064] The partition wall 102 has a first wall portion 120A and a second wall portion 120B that form a bulging structure. The first walls 120A and 120B are disposed adjacent to each other and symmetrically. Since the first walls 120A and 120B basically have the same structure, hereinafter the first walls 120A and 120B may be referred to as the wall portion 120 without any particular distinction.

[0065] The wall portion 120 has a base end portion 125 connected to the pressing portion 101, a wide portion 130 connected to the base end portion 125 and disposed spaced apart (adjacent) from the pressing portion 101, and a clamp portion 131 connected to the wide portion 130 and held by the partition holder 110. The base end portion 125, the wide portion 130, and the clamp portion 131 are integrally configured.

[0066] Each of the first walls 120A, 120B has a base end 125, a wide portion 130, and a clamp portion 131. The adjacent base ends 125 are connected to each other at the pressing portion 101. These base ends 125 extend in directions away from each other from the pressing portion 101 and have a V-shaped cross-sectional shape. In other words, the first walls 120A, 120B have V-shaped cross-sectional shapes approaching each other toward the pressing portion 101, and are connected to each other at the pressing portion 101.

[0067] The adjacent wide portions 130 have wide shapes that are spaced apart from each other. The partition holder 110 is sandwiched between these wide portions 130. The adjacent clamp portions 131 are close to each other so as to cover the partition holder 110, and are fixed to the upper end of the partition holder 110.

[0068] More specifically, the clamp portion 131 has a protrusion 131a that protrudes toward the pressing portion 101. The partition holder 110 has a fitting portion 110b having a shape corresponding to the protrusion 131a. The fitting portion 110b is formed at the upper end of the partition holder 110.

[0069] By fitting the protrusion 131a to the fitting portion 110b, the bulkhead 102 is firmly held in its entirety by the bulkhead holder 110. In the embodiment shown in Fig. 8(a), the bulkhead holder 110 is disposed in its entirety in the pressurized chamber MSP, but in one embodiment, at least a portion of the bulkhead holder 110 may be disposed in the pressurized chamber MSP. In this case, the fitting portion 110b does not necessarily have to be formed at the upper end of the bulkhead holder 110.

[0070] When the partition wall 102 is attached to the partition wall holder 110, the communication hole 110a of the partition wall holder 110 communicates with the pressurized chamber MSP of the partition wall 102. In this state, by supplying fluid to the pressurized chamber MSP through the fluid line 88, the partition wall 102 elastically deforms (expands) as a whole.

[0071] According to this embodiment, the partition wall 102 having a bulging structure is configured to apply a pressing force to the pressing area 101 by its elastic deformation (see the arrows in FIG. 5). Therefore, the elasticity of the elastic membrane 100, particularly the elasticity of the pressing area 101, can be improved.

[0072] Patent Document 1 discloses a flexible membrane having an air pressure introduction section. The flexible membrane is supported by a partition support section that supports the partition, and the partition support section is formed by a part of a supporter as a component of a polishing head. Thus, in Patent Document 1, the auxiliary air pressure area is formed by the flexible membrane and the partition support section of the supporter.

[0073] On the other hand, in this embodiment, the pressurized chamber MSP is configured from a partition wall 102 having a bulging structure. Therefore, by supplying fluid to the pressurized chamber MSP, the partition wall 102 as a whole can be largely elastically deformed, and a pressing force can be applied to the pressing part 101 more actively.

[0074] In this way, the partition 102 having a bulging structure can greatly contribute to improving the stretchability of the pressing part 101. Patent Document 1 does not disclose a flexible membrane having such a structure, and the flexible membrane of Patent Document 1 has a structure different from that of the elastic membrane 100 according to the present embodiment.

[0075] In this embodiment, the partition 102, including the wide portion 130 and the clamp portion 131, are all made of an elastic material. Therefore, the polishing head PH can be assembled simply by attaching the partition 102 to the partition holder 110 so as to cover the partition holder 110. Furthermore, by configuring the wide portion 130 to be elastically deformable, even if the elastic membrane 100 has some assembly error, the elastic membrane 100 can absorb the assembly error.

[0076] Furthermore, in this embodiment, the polishing head PH has a structure in which the partition holder 110 is sandwiched between the elastic membrane 100. With such a structure, the polishing head PH can improve the sealing performance of the pressurized chamber MSP and can prevent liquid from entering the pressurized chamber MSP. In this embodiment, the elastic membrane 100 has an elastically deformable wide portion 130. Therefore, the elastic membrane 100 can improve the assembly and sealing performance of the polishing head PH.

[0077] If the partition 102 is made of a hard material or if the distance between the elastic membrane 100 and the wafer W (i.e., the membrane height) is large, even if a fluid is supplied to the pressurized chamber MSP, the partition 102 may not be able to sufficiently improve the elasticity of the pressed portion 101. In this embodiment, the elastic membrane 100 has the partition 102 that is elastically deformable, and therefore the partition 102 can be greatly expanded and contracted.

[0078] The elastic membrane 100 aims to improve the uniformity of the wafer W by compensating for the pressure loss applied to the wafer W from the pressing portion 101. According to the present embodiment, the elastic membrane 100 having the partition wall 102 can sufficiently compensate for the pressure loss applied to the wafer W.

[0079] If the elastic film 100 has a high rubber hardness, the elastic film 100 may not expand or contract sufficiently, which may adversely affect the uniformity of the wafer W. Therefore, it is necessary to adjust the rubber hardness of the elastic film 100 by changing the thickness and shape of the elastic film 100. However, in this case, it is necessary to prepare multiple molds for manufacturing the elastic film 100 having various shapes, which is not realistic because it requires a lot of cost and time.

[0080] 8(b) and 8(c), the polishing head PH may have a widthwise gap G formed between the wall portion 120 and the partition holder 110. The widthwise gap G is formed between the wide portion 130 and the partition holder 110.

[0081] By forming the widthwise gap G, the wall portion 120 can deform more elastically without being hindered by the partition holder 110 (see FIG. 8(c)). Therefore, there is no need to change the thickness or shape of the elastic membrane 100, and the cost required for manufacturing the elastic membrane 100 can be reduced.

[0082] Fig. 9 is a diagram showing another embodiment of the partition wall. As shown in Fig. 9, the partition wall 102 has a third wall portion 120C connected to the first wall portions 120A and 120B. The third wall portion 120C extends from the connection portion of the first wall portions 120A and 120B toward the pressing portion 101.

[0083] The third wall portion 120C extends perpendicular to the pressing portion 101. The third wall portion 120C has one end connected to the pressing portion 101 and the other end connected to the base ends 125, 125 of the first walls 120A, 120B. With this structure, the partition 102 has a Y-shaped cross section.

[0084] In one embodiment, the elastic membrane 100 may have a plurality of partitions 102, including a partition 102 having a V-shaped cross-sectional shape (see Figures 1 to 8) and a partition 102 having a Y-shaped cross-sectional shape (see Figure 9).

[0085] Fig. 10(a) is a diagram showing one embodiment of the peripheral wall of the elastic membrane, and Fig. 10(b) is a diagram showing another embodiment of the peripheral wall. As shown in Fig. 10(a), the partition wall 102 constituting the pressurizing chamber MSP formed in the upper part of the pressure chamber A5 is disposed adjacent to the peripheral wall 103, and has a wall portion 120 connected to the peripheral wall 103. Hereinafter, the wall portion 120 connected to the peripheral wall 103 may be referred to as the peripheral wall side wall portion 120. The partition wall 102 having the peripheral wall side wall portion 120 may be referred to as the peripheral wall side partition wall 102.

[0086] 10(a), the peripheral side wall portion 120 has a base end portion 125 connected to the peripheral wall 103, and a wide portion 130 and a clamp portion 131 connected to the base end portion 125. The base end portion 125 extends parallel to the pressing portion 101. By supplying a fluid to a pressurizing chamber MSP formed by the partition wall 102 having a bulging structure and the peripheral wall 103, the peripheral side partition wall 102 applies a pressing force to the pressing portion 101 via the peripheral wall 103.

[0087] 10(b), the base end 125 of the peripheral side wall portion 120 may extend at an angle relative to the pressing area 101. More specifically, the base end 125 extends obliquely downward toward the pressing area 101, and is connected to the connection portion between the pressing area 101 and the peripheral wall 103 (or the pressing area 101). With this configuration, the peripheral side partition 102 can apply a pressing force to the pressing area 101 by supplying a fluid to the pressurizing chamber MSP.

[0088] 11(a) and 11(b) are diagrams showing the operation of the polishing head to suction and hold the wafer. First, a fluid is supplied to the pressure chamber MSP to bring the entire pressing portion 101 into close contact with the wafer W (see FIG. 11(a)). In this state, a vacuum is created in each of the pressure chambers A1 to A5 to form a suction space V on the lower surface of the pressing portion 101 (see FIG. 11(b)). The suction space V corresponds to a suction cup formed by the pressing portion 101.

[0089] In this way, by forming the suction space V on the lower surface of the pressing portion 101, the polishing head PH can suction and hold the wafer W (suction step). In this state, the polishing head PH is transported to a predetermined polishing position (i.e., above the polishing pad 1) and starts polishing the wafer W.

[0090] At the start of polishing the wafer W, the polishing head PH presses the wafer W against the polishing pad 1 by supplying fluid to the pressure chambers A1 to A5, and applies a pressing force to the pressing portion 101 through the partition 102 by supplying fluid to the pressure chamber MSP.

[0091] Basically, the pressure of the fluid supplied to the pressurizing chamber MSP is determined arbitrarily. In one embodiment, in order to achieve the purpose of improving the stretchability of the pressing part 101, the pressure of the fluid supplied to the pressurizing chamber MSP may be determined to be the lowest pressure among the pressure chambers A1 to A5.

[0092] In one embodiment, in order to apply a pressing force to the pressing portion 101 directly below the partition wall 102 that constitutes the pressurized chamber MSP, the pressure of the fluid supplied to the pressurized chamber MSP may be determined to be equal to or higher than the pressure of the fluid supplied to the pressure chambers A1 to A5.

[0093] Fig. 12 is a diagram showing another embodiment of the elastic membrane. As shown in Fig. 12, the elastic membrane 100 may have a suction hole H formed in the pressing portion 101. In the embodiment shown in Fig. 12, the suction hole H is formed in the pressing portion 101 that forms the pressure chamber A1.

[0094] With the wafer W in close contact with the pressing portion 101, a vacuum is formed in the pressure chamber A1, whereby the wafer W is sucked to the pressing portion 101 through the suction holes H. In this manner, the polishing head PH may suck and hold the wafer W through the suction holes H while forming the suction space V. By forming the suction holes H, moisture present between the wafer W and the pressing portion 101 can be removed through the suction holes H.

[0095] After polishing of the wafer W is completed, the polishing head PH carries out the above-mentioned suction step to transport the wafer W to a predetermined position for the next process while suction-holding the wafer W. The polishing head PH is configured to release the wafer W that has been transported to the position for the next process.

[0096] Fig. 13 is a diagram showing an operation of the polishing head to detach the wafer. As shown in Fig. 13, the control device 10 is configured to form a vacuum in the pressure chamber MSP and supply a fluid to the pressure chambers A1 to A5, thereby detaching the wafer W from the elastic film 100 (detaching step).

[0097] By the above-mentioned removal process, the pressing portion 101 immediately below the partition wall 102 constituting the pressurizing chamber MSP approaches the carrier 71, while the pressing portions 101 forming the respective pressure chambers A1 to A5 expand downward. In this manner, the polishing head PH exposes the gap between the pressing portion 101 and the wafer W.

[0098] 13, the polishing apparatus PA is provided with a release nozzle RN that sprays a fluid toward the gap between the pressing portion 101 and the wafer W. Examples of the fluid sprayed from the release nozzle RN include deionized water (DIW) and nitrogen gas. After the wafer W detachment step is performed, the wafer W is reliably detached from the polishing head PH by spraying the fluid from the release nozzle RN toward the gap between the pressing portion 101 and the wafer W.

[0099] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0100] 1 polishing pad 1a Polished surface 2 Polishing table 3 Polishing fluid supply nozzle 5 Vertical movement mechanism 6 Rotation mechanism 7. Swing Mechanism 10 Control device 10a Storage section 10b Arithmetic unit 12 Arm shaft 14 Swing Arm 14a Support stand 16 Head shaft 20 Swing motor 22 Rotational motor 23 Rotating Cylinder 24 Timing belt 25A, 25B bearings 30 Vertical movement motor 31 Connecting members 32 Rotary joint 33 Fluid Line 36 Pressure Regulating Device 41 Dresser 49 Head body 53 Flange 56 Retainer ring pressing mechanism 57 Retainer ring mechanism 70 Spacer 71 Career 75 Retainer ring 76 Rolling Diaphragm 77 Fluid Line 88 Fluid Line 100 Elastic membrane 101 Pressure Area 102 Bulkhead (including peripheral bulkhead) 103 Peripheral wall 110 Bulkhead Holder 110a Distribution hole 110b Mating part 120 Wall portion (including peripheral wall side wall portion) 120A First wall 120B 2nd wall section 120C 3rd wall section 125 Proximal end 130 Wide section 131 Clamp section 131a protrusion PA polishing equipment PH Polishing Head ES Film Thickness Sensor SP Retainer ring pressure chamber CL1 Central axis of polishing table CL2 Polishing head central axis A1(A1-A~A1-D) Pressure chamber A2(A2-A~A2-D) Pressure chamber A3(A3-A~A3-D) Pressure chamber A4 (A4-A~A4-D) Pressure chamber A5 (A5-A~A5-D) Pressure chamber MSP Pressurized Chamber H Suction hole G Width direction gap V Adsorption space RN Release Nozzle

Claims

1. 1. An elastic membrane applicable to a polishing head for polishing a substrate, comprising: The elastic membrane is A pressing portion that presses the substrate; and a partition wall having a bulging structure that forms a pressure chamber for applying a pressing force to the pressing portion.

2. The partition wall has a first wall portion and a second wall portion that form the bulge structure, The first wall portion and the second wall portion are Wide portions spaced apart from each other; The elastic membrane of claim 1 , further comprising: clamping portions connected to said wide portion and adjacent to each other.

3. the partition wall has a first wall portion and a second wall portion having a V-shaped cross section that are close to each other toward the pressing portion, The elastic membrane according to claim 1 , wherein the first wall portion and the second wall portion are connected to each other at the pressing portion.

4. The partition wall has a first wall portion, a second wall portion, and a third wall portion each having a Y-shaped cross section, The elastic membrane according to claim 1 , wherein the third wall portion is connected to the first wall portion and the second wall portion, and extends from a connection portion between the first wall portion and the second wall portion toward the pressing portion.

5. the partition wall has a first pressure chamber and a second pressure chamber disposed on either side of the pressurizing chamber, The elastic membrane according to claim 1 , wherein the pressure chamber is disposed above the first pressure chamber and the second pressure chamber.

6. The elastic membrane has a peripheral wall that defines its outer shape, The elastic membrane according to claim 1 , wherein the partition has a peripheral side wall portion disposed adjacent to the peripheral wall and extending at an angle with respect to the pressing portion.

7. An elastic membrane according to any one of claims 1 to 6; a head body that holds the elastic membrane.

8. the head body includes a partition holder that holds the partition, The polishing head according to claim 7 , wherein at least a portion of the partition holder is disposed in the pressure chamber.

9. The polishing head according to claim 8 , wherein the polishing head has a widthwise gap formed between the partition and the partition holder.

10. holding the substrate with an elastic membrane that presses against the substrate; While holding the substrate, a fluid is supplied to a pressure chamber formed by a pressing portion for pressing the substrate, thereby pressing the substrate against the polishing pad; A polishing method comprising: supplying a fluid into a pressure chamber formed by a partition having a bulging structure, and applying a pressing force to the pressing portion.

11. 11. The polishing method according to claim 10, wherein the step of holding the substrate includes the step of supplying a fluid to the pressure chamber and forming a vacuum in the pressure chamber to form an adsorption space below the pressing portion and adsorb the substrate.

12. 11. The polishing method according to claim 10, further comprising the step of: forming a vacuum in the pressure chamber and supplying a fluid to the pressure chamber, after polishing of the substrate is completed, thereby detaching the substrate from the elastic film.

13. The partition wall has a first wall portion and a second wall portion that form the bulge structure, The first wall portion and the second wall portion are Wide portions spaced apart from each other; 11. The polishing method according to claim 10, further comprising: clamping portions connected to the wide portion and adjacent to each other.

14. the partition wall has a first wall portion and a second wall portion having a V-shaped cross section that are close to each other toward the pressing portion, The polishing method according to claim 10 , wherein the first wall portion and the second wall portion are connected to each other at the pressing portion.

15. The partition wall has a first wall portion, a second wall portion, and a third wall portion each having a Y-shaped cross section, The polishing method according to claim 10 , wherein the third wall portion is connected to the first wall portion and the second wall portion, and extends from a connection portion between the first wall portion and the second wall portion toward the pressing portion.

16. The elastic membrane has a peripheral wall that defines its outer shape, The polishing method according to claim 10 , wherein the partition has a peripheral side wall portion disposed adjacent to the peripheral wall and extending at an angle with respect to the pressing portion.

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