Elastic membrane and method for manufacturing the same

Abstract

To provide an elastic film which has physical properties determined for each part of the elastic film, and enables uniform polishing of workpiece.SOLUTION: An elastic film 30 includes a contact part 31 having a workpiece pressing surface 31a for pressing workpiece W against a polished surface 2a, and partition walls 32 to 37 which extend upward from the contact part 31 and form pressure chambers C1 to C6, wherein at least a part of the contact part 31 and the partition walls 32 to 37 are composed of a first rubber structure 41 and a second rubber structure 42 that are integrally molded, the first rubber structure 41 has first hardness, the second rubber structure 42 has second hardness lower than the first hardness, the first rubber structure 41 includes the workpiece pressing surface 31, and the second rubber structure 42 includes at least a part of the partition walls 32 to 37.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an elastic membrane for use in a polishing head for polishing workpieces such as wafers, substrates, panels, etc. used in the manufacture of semiconductor devices, and to a method for manufacturing the elastic membrane. [Background technology]

[0002] Chemical mechanical polishing (CMP) is a well-known technique used in the manufacturing process of semiconductor devices. CMP is a technique in which a polishing solution containing abrasive grains such as silica (SiO2) is supplied onto the polishing surface of a polishing pad while a workpiece is brought into sliding contact with the polishing surface. A polishing apparatus for performing CMP includes a polishing table that supports a polishing pad with a polishing surface, and a polishing head that presses the workpiece against the polishing pad.

[0003] The polishing head is configured to press the workpiece against the polishing pad using an elastic membrane that forms a pressure chamber. Pressurized gas is supplied into the pressure chamber, and the gas pressure is applied to the workpiece via the elastic membrane. Therefore, the force with which the workpiece is pressed against the polishing pad can be adjusted by the pressure inside the pressure chamber. In order to efficiently transmit the gas pressure to the workpiece and press the workpiece with the appropriate force from the center to the edge of the workpiece, the elastic membrane is generally made of a flexible material such as rubber.

[0004] Typically, a workpiece is required to have a uniform film thickness distribution over its entire surface. Therefore, an elastic membrane forming multiple concentric pressure chambers has been conventionally used. When the initial film thickness varies along the radial direction of the workpiece, the polishing rate (also called removal rate) along the radial direction of the workpiece can be adjusted by adjusting the pressure in the multiple pressure chambers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-274415 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-111717 Summary of the Invention [Problem to be solved by the invention]

[0006] 10 is a cross-sectional view showing a portion of a polishing head 105 equipped with an elastic membrane 130 that forms multiple pressure chambers C1 to C6. The elastic membrane 130 includes a contact portion 131 having a workpiece pressing surface 131a that contacts the workpiece W, and partition walls 132 to 137 that extend upward from the contact portion 131 and form the pressure chambers C1 to C6.

[0007] The partition wall 132 is the outermost partition wall and can also be referred to as a side wall. If the partition wall 132 comes into contact with the retaining ring 128 when gas is supplied to the pressure chamber C1, the pressing force on the workpiece W will vary in the circumferential direction of the workpiece W. For this reason, the partition wall 132 is required to have sufficient rigidity to prevent it from collapsing outward and to avoid contact with the retaining ring 128 due to deformation of the elastic membrane 130. On the other hand, the partition wall 132 is required to have sufficient flexibility to extend downward when gas is supplied to the pressure chamber C1.

[0008] The partitions 133-137, which are located inside the partition 132, are required to have flexibility such that they stretch downward when gas is supplied to the pressure chambers C2-C6. If the partitions 133-137 are not flexible enough, the workpiece pressing surface 131a is pulled up at the connection between the contact portion 131 and the partitions 133-137, as shown in Figure 10, and the pressing force on the workpiece W is locally reduced.

[0009] The contact portion 131 is required to have an appropriate rigidity so that it does not twist when the workpiece W is polished, is resistant to wear due to friction with the workpiece W, and allows the workpiece W to easily separate from the contact portion 131 after polishing. Thus, in order to achieve a uniform film thickness distribution on the workpiece, each part of the elastic film is required to have appropriate rigidity and flexibility according to its function.

[0010] Patent Document 1 describes a technique in which a diaphragm is provided on the substrate holding surface side of an elastic membrane to smooth the gradient of the polishing pressure (polishing rate) at the boundary between two adjacent regions (areas). Patent Document 2 also describes a technique in which the contact portion of the elastic membrane is reinforced with a resin plate or a thread-like member to reduce contact between the elastic membrane and a retainer ring and prevent loosening of the contact portion or wrinkles from forming on the contact surface. However, these techniques require the provision of a member other than the elastic material that constitutes the elastic membrane.

[0011] Therefore, an object of the present invention is to provide an elastic film that has the physical properties required for each part of the elastic film and that can uniformly polish a workpiece, and a method for manufacturing such an elastic film. [Means for solving the problem]

[0012] In one aspect, there is provided an elastic membrane for use in a polishing head for polishing a workpiece, for pressing the workpiece against a polishing surface, the elastic membrane comprising: an abutment portion having a workpiece pressing surface for pressing the workpiece against the polishing surface; and a partition wall extending upward from the abutment portion and forming a pressure chamber, wherein at least a portion of the abutment portion and the partition wall are composed of an integrally molded first rubber structure and a second rubber structure, the first rubber structure having a first hardness and the second rubber structure having a second hardness lower than the first hardness, the first rubber structure including the workpiece pressing surface, and the second rubber structure including at least a portion of the partition wall. In one embodiment, the partition wall is connected to the outer edge of the abutment portion, the first rubber structure includes at least a portion of the lower part of the partition wall, and the second rubber structure includes the upper part of the partition wall. In one embodiment, the upper portion of the partition wall has a bent portion configured to be expandable and contractible.

[0013] In one embodiment, the partition wall has a first partition wall and a second partition wall that form a plurality of pressure chambers, the first partition wall is connected to the outer edge of the abutment portion, the second partition wall is located more inward than the first partition wall, and the second rubber structure includes the second partition wall. In one embodiment, the first rubber structure includes at least a portion of the lower part of the first partition wall, and the second rubber structure includes the upper part of the first partition wall. In one embodiment, the upper portion of the first partition wall has a bent portion configured to be expandable and contractible. In one embodiment, the first rubber structure and the second rubber structure have unevenness on the surface that is the interface between the first rubber structure and the second rubber structure.

[0014] In one aspect, there is provided a method for manufacturing an elastic membrane used in a polishing head for polishing a workpiece, for pressing the workpiece against a polishing surface, the method including the steps of: molding either a first rubber structure having a first hardness or a second rubber structure having a second hardness lower than the first hardness; molding the other of the first rubber structure and the second rubber structure; and joining the first rubber structure and the second rubber structure to integrally mold the first rubber structure and the second rubber structure; the elastic membrane includes an abutment portion having a workpiece pressing surface for pressing the workpiece against the polishing surface, and a partition wall extending upward from the abutment portion and forming a pressure chamber, the first rubber structure including the workpiece pressing surface, and the second rubber structure including at least a portion of the partition wall. In one embodiment, the method for producing an elastic membrane further includes a secondary vulcanization step of heating the integrally molded first rubber structure and second rubber structure. In one embodiment, in the step of molding the first rubber structure or the step of molding the second rubber structure, concaves and convexes are molded on the surface that will be the interface between the first rubber structure and the second rubber structure. [Effects of the Invention]

[0015] According to the present invention, a workpiece is polished using an elastic membrane in which at least two rubber structures having appropriately different hardnesses for different portions are integrally molded, thereby achieving a uniform film thickness distribution on the workpiece. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram illustrating an embodiment of a polishing apparatus. [Figure 2] FIG. 2 is a cross-sectional view showing one embodiment of a polishing head. [Figure 3] FIG. 1 is a cross-sectional view illustrating one embodiment of an elastic membrane. [Figure 4] 4(a) to 4(c) are diagrams illustrating an example of a method for manufacturing an elastic film. [Figure 5] 5(a) and 5(b) are diagrams for explaining the continuation of FIG. 4(c). [Figure 6] 5 is a flowchart of the manufacturing method shown in FIGS. 4(a) to 4(c) and FIGS. 5(a) to 5(b). [Figure 7] 7(a) to 7(c) are diagrams illustrating another example of a method for manufacturing an elastic film. [Figure 8] 8(a) and 8(b) are diagrams for explaining the continuation of FIG. 7(c). [Figure 9] 8 is a flowchart of the manufacturing method shown in FIGS. 7(a) to 7(c) and FIGS. 8(a) to 8(b). [Figure 10] 1 is a cross-sectional view showing a portion of a polishing head having an elastic membrane that forms a plurality of pressure chambers. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic diagram showing one embodiment of a polishing apparatus 1. The polishing apparatus 1 is an apparatus for chemically and mechanically polishing a workpiece W, such as a wafer, substrate, or panel used in the manufacture of semiconductor devices. As shown in FIG. 1, the polishing apparatus 1 includes a polishing table 3 that supports a polishing pad 2 having a polishing surface 2a, a polishing head 5 that presses the workpiece W against the polishing surface 2a, and a polishing liquid supply nozzle 8 that supplies a polishing liquid to the polishing surface 2a.

[0018] The polishing table 3 is connected to a table motor 6 disposed below it via a table shaft 3a, and the table motor 6 is configured to rotate the polishing table 3 and the polishing pad 2 together in the direction indicated by the arrow. The surface of the polishing pad 2 forms a polishing surface 2a that polishes the workpiece W.

[0019] The polishing head 5 is configured to be able to hold a workpiece W on its underside. The polishing head 5 is fixed to the end of a polishing head shaft 11, which is rotatably supported by a head swing arm 13. The head swing arm 13 is rotatably supported by a support shaft 14. The polishing head shaft 11 is connected to a polishing head motor (not shown). The polishing head motor is configured to rotate the polishing head 5 together with the polishing head shaft 11 in the direction indicated by the arrow.

[0020] The polishing head shaft 11 is further connected to a polishing head up-down movement mechanism (not shown), which is configured to move the polishing head shaft 11 and the polishing head 5 up and down relative to the head swing arm 13.

[0021] The polishing apparatus 1 further includes an operation control unit 20 that controls the operations of the polishing head 5, table motor 6, polishing head motor, polishing head up-down movement mechanism, and polishing liquid supply nozzle 8. The operation control unit 20 is composed of at least one computer.

[0022] The workpiece W is polished as follows: While the polishing table 3 and polishing head 5 are rotated in the directions indicated by the arrows in Figure 1, a polishing liquid is supplied from a polishing liquid supply nozzle 8 to the polishing surface 2a of the polishing pad 2 on the polishing table 3. While the workpiece W is rotated by the polishing head 5, the polishing head 5 presses the workpiece W against the polishing surface 2a of the polishing pad 2 with the polishing liquid present between the polishing pad 2 and the workpiece W. The surface of the workpiece W is polished by a combination of the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and / or the polishing pad 2.

[0023] Next, the polishing head 5 will be described. Fig. 2 is a cross-sectional view showing one embodiment of the polishing head 5. The polishing head 5 includes a carrier 25 fixed to the end of the polishing head shaft 11, an elastic membrane 30 attached to the lower part of the carrier 25, and a retainer ring 28 disposed below the carrier 25. The retainer ring 28 is disposed around the elastic membrane 30. The retainer ring 28 is an annular structure that holds the workpiece W to prevent the workpiece W from flying out of the polishing head 5 while it is being polished.

[0024] The elastic membrane 30 includes a contact portion 31 having a workpiece pressing surface 31a that can contact the upper surface of the workpiece W, and partitions 32 to 37 that extend upward from the contact portion 31. The contact portion 31 has substantially the same size and shape as the upper surface of the workpiece W. The partitions 32 to 37 are endless walls that are arranged concentrically. The first partition 32 is the outermost partition. The first partition 32 can also be called a side wall.

[0025] More specifically, the partition walls 32 to 37 are a first partition wall 32 connected to the outer edge of the abutment portion, a second partition wall 33 located more inward than the first partition wall 32, a third partition wall 34 located more inward than the second partition wall 33, a fourth partition wall 35 located more inward than the third partition wall 34, a fifth partition wall 36 located more inward than the fourth partition wall 35, and a sixth partition wall 37 located more inward than the fifth partition wall 36. The first partition wall 32 has a bent portion 32a at its upper portion that is expandable and contractible. The second partition wall 33 to the sixth partition wall 37 extend obliquely upward and radially inward from the abutment portion 31.

[0026] The shapes of the first partition wall 32 to the sixth partition wall 37 of the present invention are not limited to this embodiment. In one embodiment, the first partition wall 32 may extend upward from the contact portion 31 without having the bent portion 32a, or may branch into multiple parts on the way upward from the contact portion 31. In one embodiment, the second partition wall 33 to the sixth partition wall 37 may extend upward from the contact portion 31 without being inclined, or may be bent on the way upward from the contact portion 31.

[0027] Six pressure chambers C1 to C6 are provided between the elastic membrane 30 and the carrier 25. The pressure chambers C1 to C6 are formed by at least the contact portion 31 of the elastic membrane 30 and the partition walls 32 to 37. The pressure chamber C1 is located between the first partition wall 32 and the second partition wall 33, the pressure chamber C2 is located between the second partition wall 33 and the third partition wall 34, the pressure chamber C3 is located between the third partition wall 34 and the fourth partition wall 35, the pressure chamber C4 is located between the fourth partition wall 35 and the fifth partition wall 36, the pressure chamber C5 is located between the fifth partition wall 36 and the sixth partition wall 37, and the pressure chamber C6 is located within the sixth partition wall 37. The pressure chambers C1 to C5 are annular, and the central pressure chamber C6 is circular. These pressure chambers C1 to C6 are arranged concentrically. In an embodiment, the pressure chambers C1 to C6 may have other shapes.

[0028] In this embodiment, the elastic membrane 30 forms six pressure chambers C1 to C6, but the present invention is not limited to this embodiment. In an embodiment, the elastic membrane 30 may form fewer than six or more than six pressure chambers. That is, in an embodiment, fewer than six partition walls may be provided, or more than six partition walls may be provided. For example, only the first partition wall 32 may be provided, and the elastic membrane 30 may form only one pressure chamber C1.

[0029] Gas transfer lines F1, F2, F3, F4, F5, and F6 are connected to the pressure chambers C1, C2, C3, C4, C5, and C6, respectively. One end of the gas transfer lines F1 to F6 is connected to a compressed gas supply source (not shown) that serves as a utility supply source provided in the factory where the polishing apparatus 1 is installed. Compressed gas such as compressed air is supplied to the pressure chambers C1, C2, C3, C4, C5, and C6 through the gas transfer lines F1, F2, F3, F4, F5, and F6, respectively.

[0030] An annular rolling diaphragm 38 is disposed between the carrier 25 and the retaining ring 28, and a pressure chamber C7 is formed inside the rolling diaphragm 38. The pressure chamber C7 is connected to the compressed gas supply source via a gas transfer line F7. The compressed gas is supplied into the pressure chamber C7 through the gas transfer line F7, and the pressure chamber C7 presses the retaining ring 28 against the polishing surface 2a of the polishing pad 2.

[0031] The gas transfer lines F1 to F7 extend via a rotary joint 18 attached to the polishing head shaft 11. The gas transfer lines F1, F2, F3, F4, F5, F6, and F7, which communicate with the pressure chambers C1, C2, C3, C4, C5, C6, and C7, are provided with pressure regulators R1, R2, R3, R4, R5, R6, and R7, respectively. Compressed gas from a compressed gas supply source is supplied independently into the pressure chambers C1 to C7 through the pressure regulators R1 to R7. The pressure regulators R1 to R7 are configured to adjust the pressure of the compressed gas in the pressure chambers C1 to C7.

[0032] The pressure regulators R1 to R7 can change the internal pressures of the pressure chambers C1 to C7 independently of one another, thereby independently adjusting the six corresponding regions of the workpiece W and the pressing force of the retainer ring 28 against the polishing pad 2. The region of the workpiece W corresponding to the pressure chamber C1 is an annular region including the edge of the workpiece W. The region of the workpiece W corresponding to the pressure chamber C2 is an annular region located more inward than the region of the workpiece W corresponding to the pressure chamber C1. The region of the workpiece W corresponding to the pressure chamber C3 is an annular region located more inward than the region of the workpiece W corresponding to the pressure chamber C2. The region of the workpiece W corresponding to the pressure chamber C4 is an annular region located more inward than the region of the workpiece W corresponding to the pressure chamber C3. The region of the workpiece W corresponding to the pressure chamber C5 is an annular region located more inward than the region of the workpiece W corresponding to the pressure chamber C4. The region of the workpiece W corresponding to the pressure chamber C6 is an annular region located more inward than the region of the workpiece W corresponding to the pressure chamber C5.

[0033] The gas transfer lines F1-F7 are also connected to atmospheric release valves (not shown), allowing the pressure chambers C1-C7 to be opened to the atmosphere. The pressure regulators R1-R7 are connected to an operation control unit 20. The operation control unit 20 sends target pressure values ​​for the pressure chambers C1-C7 to the pressure regulators R1-R7, and the pressure regulators R1-R7 operate to maintain the pressures in the pressure chambers C1-C7 at the corresponding target pressure values.

[0034] The polishing head 5 can apply independent polishing pressures to multiple regions of the workpiece W. For example, the polishing head 5 can press different regions of the surface of the workpiece W against the polishing surface 2a of the polishing pad 2 with different polishing pressures. Therefore, the polishing head 5 can control the film thickness profile of the workpiece W to achieve a target film thickness profile.

[0035] FIG. 3 is a cross-sectional view showing one embodiment of the elastic membrane 30. FIG. 3 shows a portion of the elastic membrane 30. The elastic membrane 30 is composed of a first rubber structure 41 and a second rubber structure 42 made of rubbers having different hardnesses. More specifically, the elastic membrane 30 has the first rubber structure 41 having a first hardness and the second rubber structure 42 having a second hardness lower than the first hardness. The first rubber structure 41 and the second rubber structure 42 are integrally molded into a single structure. Examples of elastic rubbers that make up the first rubber structure 41 and the second rubber structure 42 include silicone rubber, EPDM (ethylene propylene diene rubber), and fluororubber. In this embodiment, silicone rubber is used.

[0036] The first rubber structure 41 includes a lower abutting portion 31b having a workpiece pressing surface 31a. The lower abutting portion 31b is a part of the abutting portion 31, more specifically, the lower portion of the abutting portion 31. The first rubber structure 41 further includes a lower partition wall 32b that is the lower portion of the first partition wall 32. The lower partition wall 32b forms the outer side of the lower portion of the first partition wall 32 and extends upward from the lower abutting portion 31b. The lower abutting portion 31b and the lower partition wall 32b are integrally molded.

[0037] The second rubber structure 42 includes an upper abutting portion 31c, an upper partition wall 32c, an inner wall portion 32d, and the second partition wall 33 to the sixth partition wall 37. The upper abutting portion 31c is a part of the abutting portion 31, more specifically, an upper portion of the abutting portion 31 located above the lower abutting portion 31b. The upper abutting portion 31c is thinner than the lower abutting portion 31b. The upper partition wall 32c forms the upper portion of the first partition wall 32 and is located above the lower partition wall 32b. The upper partition wall 32c has a bent portion 32a. The inner wall portion 32d forms the inside of the lower portion of the first partition wall 32 and extends upward from the upper abutting portion 31c. The inner wall portion 32d is located inside the lower partition wall 32b. The upper contact portion 31c, the upper partition wall 32c, the inner wall portion 32d, and the second to sixth partition walls 33 to 37 are integrally molded.

[0038] The first rubber structure 41 and the second rubber structure 42 are integrally molded and joined without the use of adhesive to form an integrated structure. The surface that forms the interface between the first rubber structure 41 and the second rubber structure 42 may have irregularities to improve adhesion. The interface between the first rubber structure 41 and the second rubber structure 42 is the interface between the lower abutting portion 31b and the upper abutting portion 31c of the abutting portion 31, and the interface between the lower partition wall 32b and the inner wall portion 32d of the first partition wall 32. By molding irregularities into these interface surfaces, the contact area between the first rubber structure 41 and the second rubber structure 42 increases, and the first rubber structure 41 and the second rubber structure 42 are more firmly integrated.

[0039] In one embodiment, the second rubber structure 42 may not have the upper abutting portion 31c. In this case, the second partition wall 33 to the sixth partition wall 37 of the second rubber structure 42 extend upward from the abutting portion 31 of the first rubber structure 41. Also, in one embodiment, the second rubber structure 42 may not have the inner wall portion 32d. In this case, the upper partition wall 32c extends upward from the upper end of the lower partition wall 32b of the first rubber structure 41.

[0040] According to this embodiment, the elastic membrane 30 includes the first rubber structure 41 and the second rubber structure 42 having different hardnesses, thereby enabling the elastic membrane 30 to have appropriate rigidity and flexibility according to the physical properties required for each portion of the elastic membrane 30. The first rubber structure 41 has a first hardness, and the second rubber structure 42 has a second hardness. The second hardness is lower than the first hardness. As a result, the first rubber structure 41 has appropriate rigidity, and the second rubber structure 42 has appropriate flexibility. For example, the first hardness is 80 degrees (Durometer Type A hardness) and the second hardness is 50 degrees (Durometer Type A hardness), but the present invention is not limited to this.

[0041] The upper and lower parts of the first partition wall 32 are required to have different physical properties. The lower partition wall 32b is required to have appropriate rigidity so that it does not collapse outward and come into contact with the retaining ring 28 when gas is supplied to the pressure chamber C1 (see FIG. 2). The lower partition wall 32b is made of the first rubber structure 41 and is therefore more rigid than the second rubber structure 42. This prevents contact between the lower partition wall 32b and the retaining ring 28 and makes it possible to uniformly apply a pressing force to the workpiece W.

[0042] The upper partition 32c is required to have appropriate flexibility so that it can expand downward when gas is supplied to the pressure chamber C1. Because the upper partition 32c is made of the second rubber structure 42, it is more flexible than the first rubber structure 41. This allows the upper partition 32c to expand and contract in accordance with the pressure of the gas supplied to the pressure chamber C1, thereby enabling flexible adjustment of the pressing force on the workpiece W. Even if the lower partition 32b has a relatively high hardness, the expansion and contraction of the upper partition 32c allows the pressure inside the pressure chamber C1 to be appropriately transmitted to the outer edge of the workpiece W. In particular, in this embodiment, the bent portion 32a, which is a part of the upper partition 32c, can improve the expansion and contraction of the upper partition 32c.

[0043] The second partition wall 33 to the sixth partition wall 37 are required to have flexibility such that they stretch downward when gas is supplied to the pressure chambers C2 to C6 (see FIG. 2). The second partition wall 33 to the sixth partition wall 37 are made of the second rubber structure 42 and therefore have more flexibility than the first rubber structure 41. This allows the second partition wall 33 to the sixth partition wall 37 to flexibly stretch in accordance with the pressure of the gas supplied to the pressure chambers C2 to C6 (see FIG. 2), and the elastic membrane 30 to press the workpiece W with an appropriate pressing force.

[0044] The lower contact portion 31b is made of the first rubber structure 41 and therefore has greater rigidity than the second rubber structure 42. This prevents upward deformation of the workpiece pressing surface 31a at the connection between the second partition wall 33 to the sixth partition wall 37 and the contact portion 31, thereby preventing a local decrease in the pressing force on the workpiece W. Furthermore, the contact portion 31 is prevented from twisting as the polishing head 5 (see FIG. 1) rotates when polishing the workpiece W, making the contact portion 31 less susceptible to wear due to friction with the workpiece W. Furthermore, after polishing, the workpiece W does not adhere to the contact portion 31 and is easily released from the contact portion 31.

[0045] In this way, by using an elastic film 30 with different physical properties in different regions, the polishing head 5 can polish the workpiece W with an appropriate pressing force to achieve the target film thickness distribution on the workpiece W. Furthermore, because the first rubber structure 41 and the second rubber structure 42 are integrally molded, there is no need to use an adhesive to secure the first rubber structure 41 and the second rubber structure 42 to each other. Therefore, appropriate rigidity and flexibility can be achieved in each region without affecting the physical properties of the rubber that makes up the elastic film 30.

[0046] Next, a method for manufacturing the elastic membrane 30 will be described. Figures 4(a) to 4(c) and 5(a) to 5(b) are views illustrating one example of a method for manufacturing the elastic membrane 30. In the manufacturing method shown in Figures 4(a) to 4(c) and 5(a) to 5(b), the first rubber structure 41 is molded first, and then the second rubber structure 42 is molded, so that the first rubber structure 41 and the second rubber structure 42 are integrally molded.

[0047] First, as shown in Fig. 4(a), a first rubber material 43, which is the material of the first rubber structure 41, is poured into the space between a first molding die 51 and a second molding die 52. Next, as shown in Fig. 4(b), when the first molding die 51 and the second molding die 52 are fitted together and pressure is applied to the first rubber material 43, the first rubber material 43 fills the gap between the first molding die 51 and the second molding die 52. The first rubber material 43 is heated while being pressurized by the first molding die 51 and the second molding die 52, thereby molding the first rubber structure 41.

[0048] In order to form irregularities on the surface that forms the interface between the first rubber structure 41 and the second rubber structure 42, the second molding die 52 may have irregularities on its surface 52a that contacts the first rubber material 43. As one example, these irregularities are formed by a roughening treatment such as embossing or blasting. The irregularities on the surface 52a form irregularities on the surface of the lower contact portion 31b (see FIG. 3) of the first rubber structure 41 and the surface of the lower partition wall 32b (see FIG. 3), which form the interface with the second rubber structure 42. Forming irregularities on the surface of the first rubber structure 41 increases the contact area between the first rubber structure 41 and the second rubber structure 42, enabling the first rubber structure 41 and the second rubber structure 42 to be more firmly integrated.

[0049] As shown in Figure 4(c), the molded first rubber structure 41 is held in a first molding die 51 by a known method such as vacuum suction, and the second molding die 52 is removed. The configuration of the vacuum suction mechanism is omitted in Figure 4(c). Next, the process of molding the second rubber structure 42 will be described.

[0050] As shown in Figure 5(a), a second rubber material 44, which is the material of the second rubber structure 42, is poured into the space between a first molding die 51 holding the first rubber structure 41 and a third molding die 53. The third molding die 53 has recesses 53a for molding the partition walls 32 to 37 (see Figure 3).

[0051] Next, as shown in FIG. 5(b), when the first molding die 51 and the third molding die 53 are fitted together and pressure is applied to the second rubber material 44, the second rubber material 44 enters the recess 53a of the third molding die 53. When the first molding die 51 and the third molding die 53 are fitted together, a gap 51a of approximately 0.5 mm is formed between the first rubber structure 41 held by the first molding die 51 and the third molding die 53. This gap 51a forms the upper abutment portion 31c (see FIG. 3) of the second rubber structure 42. By heating the second rubber material 44 while it is pressurized by the first molding die 51 and the third molding die 53, the second rubber structure 42 bonded to the first rubber structure 41 is formed, and the first rubber structure 41 and the second rubber structure 42 are integrally molded.

[0052] Thereafter, the integrated first rubber structure 41 and second rubber structure 42 are removed from the first molding die 51 and the third molding die 53. The third molding die 53 may be configured by combining a plurality of molds such as a core mold and a base mold in order to remove the second rubber structure 42, which has a complex shape.

[0053] The integrally molded first rubber structure 41 and second rubber structure 42 are bonded at their interface, but the cross-linking reaction between the first rubber material 43 and the second rubber material 44 has not yet progressed completely. The integrally molded first rubber structure 41 and second rubber structure 42 are heated to perform secondary vulcanization, which further advances the cross-linking reaction between the first rubber material 43 and the second rubber material 44. In this secondary vulcanization step, for example, the integrated first rubber structure 41 and second rubber structure 42 are heated in an oven (constant temperature equipment) at 200°C for 3 to 4 hours. This completes the elastic membrane 30 composed of the first rubber structure 41 and the second rubber structure 42.

[0054] FIG. 6 is a flowchart of the manufacturing method shown in FIGS. 4(a) to 4(c) and 5(a) to 5(b). In step S101, as shown in FIG. 4(a), the first rubber material 43 is poured into the space between the first molding die 51 and the second molding die 52. In step S102, as shown in Fig. 4(b), the first molding die 51 and the second molding die 52 are fitted together to apply pressure to the first rubber material 43, and the first rubber material 43 is heated to form the first rubber structure 41. Thereafter, as shown in Fig. 4(c), the second molding die 52 is removed.

[0055] In step S103, as shown in FIG. 5(a), the second rubber material 44 is poured into the space between the first molding die 51 and the third molding die 53. In step S104, as shown in FIG. 5(b), the first molding die 51 and the third molding die 53 are fitted together to pressurize the second rubber material 44, and the second rubber material 44 is heated to form the second rubber structure 42 joined to the first rubber structure 41, thereby integrally molding the first rubber structure 41 and the second rubber structure 42. In step S105, the integrated first rubber structure 41 and second rubber structure 42 are removed from the first molding die 51 and the third molding die 53. In step S106, the integrated first rubber structure 41 and second rubber structure 42 are heated to perform secondary vulcanization, which further promotes the cross-linking reaction, thereby completing the elastic membrane 30 composed of the first rubber structure 41 and the second rubber structure 42.

[0056] According to this embodiment, the second rubber structure 42 joined to the first rubber structure 41 is molded before the crosslinking reaction has progressed completely (before secondary vulcanization), so the first rubber structure 41 and the second rubber structure 42 can be integrated while the crosslinking reaction between them progresses. Furthermore, this method can reduce the number of steps compared to molding the first rubber structure 41 and the second rubber structure 42 separately and then joining them, thereby improving productivity.

[0057] 7(a) to 7(c) and 8(a) to 8(b) are diagrams illustrating another example of the method for manufacturing the elastic membrane 30. In the manufacturing method shown in Figures 7(a) to 7(c) and 8(a) to 8(b), the second rubber structure 42 is molded first, and then the first rubber structure 41 is molded, so that the first rubber structure 41 and the second rubber structure 42 are integrally molded.

[0058] First, as shown in Fig. 7(a), the second rubber material 44, which is the material of the second rubber structure 42, is poured into the space between the first molding die 54 and the second molding die 55. The second molding die 55 has recesses 55a for molding the partition walls 32 to 37 (see Fig. 3).

[0059] Next, as shown in FIG. 7(b), when the first molding die 54 and the second molding die 55 are fitted together and pressure is applied to the second rubber material 44, the second rubber material 44 enters the recess 55a of the second molding die 55. When the first molding die 54 and the second molding die 55 are fitted together, a gap 54a of approximately 0.5 mm is formed between the first molding die 54 and the second molding die 55. This gap 54a forms the upper abutment portion 31c (see FIG. 3) of the second rubber structure 42. The second rubber material 44 is heated while being compressed by the first molding die 54 and the second molding die 55, thereby forming the second rubber structure 42.

[0060] In order to form irregularities on the surface that forms the interface between the first rubber structure 41 and the second rubber structure 42, the first molding die 54 may have irregularities on its surface 54b that contacts the second rubber material 44. As one example, these irregularities are formed by roughening treatment such as embossing or blasting. The irregularities on the surface 54b form irregularities on the surface of the upper contact portion 31c of the second rubber structure 42 and on the surface of the inner wall portion 32d (see FIG. 3 ), which form the interface with the first rubber structure 41. Forming irregularities on the surface of the second rubber structure 42 increases the contact area between the first rubber structure 41 and the second rubber structure 42, enabling the first rubber structure 41 and the second rubber structure 42 to be more firmly integrated.

[0061] 7(c), the first molding die 54 is removed while the second rubber structure 42 is held by the second molding die 55. Next, the process of molding the first rubber structure 41 will be described.

[0062] As shown in FIG. 8( a), a first rubber material 43, which is the material of the first rubber structure 41, is poured into the space between a second molding die 55 holding the second rubber structure 42 and a third molding die 56. Next, as shown in FIG. 8( b), the second molding die 55 and the third molding die 56 are fitted together and the first rubber material 43 is pressurized, so that the first rubber material 43 fills the gap between the second molding die 55 and the third molding die 56. By heating the first rubber material 43 while it is pressurized by the second molding die 55 and the third molding die 56, the first rubber structure 51 bonded to the second rubber structure 42 is molded, and the first rubber structure 41 and the second rubber structure 42 are molded integrally.

[0063] Thereafter, the integrated first rubber structure 41 and second rubber structure 42 are removed from the second molding die 55 and the third molding die 56. The second molding die 55 may be configured by combining a plurality of molds such as a core mold and a base mold in order to remove the second rubber structure 42 having a complex shape.

[0064] The integrally molded first rubber structure 41 and second rubber structure 42 are bonded at their interface, but the cross-linking reaction between the first rubber material 43 and the second rubber material 44 has not yet progressed completely. The integrally molded first rubber structure 41 and second rubber structure 42 are heated to perform secondary vulcanization, which further advances the cross-linking reaction between the first rubber material 43 and the second rubber material 44. In this process, for example, the first rubber structure 41 and the second rubber structure 42 are heated in an oven (constant temperature equipment) at 200°C for 3 to 4 hours. This completes the elastic membrane 30 composed of the first rubber structure 41 and the second rubber structure 42.

[0065] FIG. 9 is a flowchart of the manufacturing method shown in FIGS. 7(a) to 7(c) and 8(a) to 8(b). In step S201, the second rubber material 44 is poured into the space between the first molding die 54 and the second molding die 55, as shown in FIG. 7(a). In step S202, as shown in Fig. 7(b), the first molding die 54 and the second molding die 55 are fitted together to apply pressure to the second rubber material 44, and the second rubber material 44 is heated to form the second rubber structure 42. Thereafter, as shown in Fig. 7(c), the first molding die 54 is removed.

[0066] In step S203, as shown in FIG. 8(a), the first rubber material 43 is poured into the space between the second molding die 55 and the third molding die . In step S204, as shown in FIG. 8(b), the second molding die 55 and the third molding die 56 are fitted together to pressurize the first rubber material 43, and the first rubber material 43 is heated to form the first rubber structure 41 joined to the second rubber structure 42, thereby integrally molding the first rubber structure 41 and the second rubber structure 42. In step S205, the integrated first rubber structure 41 and second rubber structure 42 are removed from the second molding die 55 and the third molding die 56. In step S206, the integrated first rubber structure 41 and second rubber structure 42 are heated to perform secondary vulcanization, which further promotes the cross-linking reaction, thereby completing the elastic membrane 30 composed of the first rubber structure 41 and the second rubber structure 42.

[0067] According to the present embodiment, the first rubber structure 41 joined to the second rubber structure 42 is molded before the cross-linking reaction has progressed completely (before secondary vulcanization), so the first rubber structure 41 and the second rubber structure 42 can be integrated while the cross-linking reaction between them progresses. Furthermore, the number of steps can be reduced compared to molding the first rubber structure 41 and the second rubber structure 42 separately and then joining them, thereby improving productivity.

[0068] In this embodiment, the elastic membrane 30 is made of rubber having two types of hardness, the first rubber structure 41 and the second rubber structure 42, but in one embodiment, the elastic membrane 30 may be made of material having three or more types of hardness. For example, the upper partition wall 32c of the first partition wall 32 and the second partition walls 33 to sixth partition walls 37 may be formed of rubber structures having different hardnesses.

[0069] In this embodiment, the first rubber structure 41 and the second rubber structure 42 are two types of rubber structures with different hardness, but in one embodiment, the rubber structures may have different physical properties other than hardness, such as tensile strength, elongation, and elastic modulus.

[0070] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may 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 in accordance with the technical concept defined by the claims. [Explanation of symbols]

[0071] 1 Polishing equipment 2 polishing pads 2a Polished surface 3 Polishing table 3a Table axis 5 Polishing Heads 6 Table Motor 8 Polishing liquid supply nozzle 11 Grinding head shaft 13 Head swing arm 14 Spindle 18 Rotary Joint 20 Operation control section 25 Career 28 Retainer ring 30 Elastic membrane 31 Contact part 31a Workpiece pressing surface 31b Lower contact part 31c Upper contact part 32 1st bulkhead 32a Bend part 32b Lower bulkhead 32c Upper bulkhead 32d inner wall 33 Second bulkhead 34 Third bulkhead 35 4th bulkhead 36 5th Bulkhead 37 6th Bulkhead 38 Rolling diaphragm 41 First rubber structure 42 Second rubber structure 43 First rubber material 44 Second rubber material 51,54 1st mold 52,55 2nd mold 53,56 3rd mold C1~C7 pressure chambers F1~F7 Gas transfer lines R1~R7 Pressure regulator

Claims

1. An elastic membrane used in a polishing head for chemical mechanical polishing (CMP) of a workpiece, for pressing the workpiece against a polishing surface of a polishing pad, comprising: a contact portion having a workpiece pressing surface capable of contacting an upper surface of the workpiece; a partition wall extending upward from the abutment portion and forming a pressure chamber; the abutment portion and at least a portion of the partition wall are formed from an integrally molded first rubber structure and a second rubber structure, the first rubber structure has a first hardness, and the second rubber structure has a second hardness lower than the first hardness; the workpiece pressing surface is made up of the first rubber structure, an outer side of a lower portion of the partition wall is made up of the first rubber structure, and an inner side of a lower portion of the partition wall is made up of the second rubber structure, an upper portion of the partition wall is formed by the second rubber structure, the upper portion of the partition wall has a bending portion configured to be expandable and contractible, The bending portion is formed from the second rubber structure and is located above the first rubber structure.

2. the partition wall includes a first partition wall and a second partition wall that form a plurality of pressure chambers; the first partition wall is connected to an outer edge of the abutment portion, the second partition wall is located more inward than the first partition wall and is formed by the second rubber structure, The elastic membrane of claim 1 , wherein the bent portion is at an upper portion of the first partition wall.

3. an outer side of a lower portion of the first partition wall is made up of the first rubber structure, and an inner side of a lower portion of the first partition wall is made up of the second rubber structure; The elastic membrane according to claim 2 , wherein an upper portion of the first partition wall is formed from the second rubber structure.

4. The elastic membrane according to claim 1 , wherein the first rubber structure and the second rubber structure have unevenness on a surface that is an interface between the first rubber structure and the second rubber structure.

5. An elastic membrane used in a polishing head for CMP for chemical mechanical polishing a workpiece, for pressing the workpiece against a polishing surface of a polishing pad, comprising: a contact portion having a workpiece pressing surface capable of contacting an upper surface of the workpiece; a partition wall extending upward from the abutment portion and forming a pressure chamber; the abutment portion and at least a portion of the partition wall are formed from an integrally molded first rubber structure and a second rubber structure, the first rubber structure has a first hardness, and the second rubber structure has a second hardness lower than the first hardness; the workpiece pressing surface is made up of the first rubber structure, a lower portion of the partition wall is formed by the first rubber structure, an upper portion of the partition wall is formed by the second rubber structure, the upper portion of the partition wall has a bending portion configured to be expandable and contractible, The bending portion is formed from the second rubber structure and is located above the first rubber structure.

6. The partition wall has a first partition wall and a second partition wall that form a plurality of pressure chambers, the first partition wall is connected to an outer edge of the abutment portion, the second partition wall is located more inward than the first partition wall and is formed by the second rubber structure, The elastic membrane of claim 5 , wherein the bent portion is at an upper portion of the first partition wall.

7. The lower part of the first partition wall is composed of the first rubber structure, The elastic membrane according to claim 6 , wherein an upper portion of the first partition wall is formed from the second rubber structure.

8. 1. A method for manufacturing an elastic film used in a polishing head for chemical mechanical polishing (CMP) of a workpiece, the elastic film pressing the workpiece against a polishing surface of a polishing pad, comprising: molding either a first rubber structure having a first hardness or a second rubber structure having a second hardness lower than the first hardness; a step of molding the other of the first rubber structure and the second rubber structure and joining the first rubber structure and the second rubber structure to integrally mold the first rubber structure and the second rubber structure, The elastic membrane is a contact portion having a workpiece pressing surface capable of contacting an upper surface of the workpiece; a partition wall extending upward from the abutment portion and forming a pressure chamber; the workpiece pressing surface is made up of the first rubber structure, an outer side of a lower portion of the partition wall is made up of the first rubber structure, and an inner side of a lower portion of the partition wall is made up of the second rubber structure, an upper portion of the partition wall is formed by the second rubber structure, the upper portion of the partition wall has a bending portion configured to be expandable and contractible, The bending portion is made of the second rubber structure and is located above the first rubber structure.

9. The method for manufacturing an elastic membrane according to claim 8 , further comprising a secondary vulcanization step of heating the integrally molded first rubber structure and second rubber structure.

10. 10. The method for manufacturing an elastic membrane according to claim 8 or 9, wherein in the step of molding the first rubber structure or the step of molding the second rubber structure, concavities and convexities are molded on a surface that becomes an interface between the first rubber structure and the second rubber structure.

11. A method for manufacturing an elastic film used in a polishing head for CMP for chemical mechanical polishing of a workpiece, for pressing the workpiece against a polishing surface of a polishing pad, comprising: molding either a first rubber structure having a first hardness or a second rubber structure having a second hardness lower than the first hardness; a step of molding the other of the first rubber structure and the second rubber structure and joining the first rubber structure and the second rubber structure to integrally mold the first rubber structure and the second rubber structure, The elastic membrane is a contact portion having a workpiece pressing surface capable of contacting an upper surface of the workpiece; a partition wall extending upward from the abutment portion and forming a pressure chamber; the workpiece pressing surface is made up of the first rubber structure, a lower portion of the partition wall is formed by the first rubber structure, an upper portion of the partition wall is formed by the second rubber structure, the upper portion of the partition wall has a bending portion configured to be expandable and contractible, The bending portion is made of the second rubber structure and is located above the first rubber structure.

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