Elastic membrane and method of manufacturing elastic membrane

Abstract

The present invention provides an elastic film having the required physical properties for each part of the elastic film and capable of uniformly polishing a workpiece. The elastic membrane (30) has a contact portion (31) having a workpiece pressure surface (31a) for pressurizing a workpiece (W) to a grinding surface (2a), and a partition (32 to 37) extending upward from the contact portion (31) and forming a pressure chamber (C1 to C6). At least a portion of the contact portion (31) and the partition (32 to 37) is composed of a first rubber structure (41) and a second rubber structure (42) that are integrally molded. The first rubber structure (41) has a first hardness, and the second rubber structure (42) has a second hardness lower than the first hardness. The first rubber structure (41) includes the workpiece pressure surface (31), and the second rubber structure (42) includes at least a portion of the partition (32 to 37).

Description

Technology Field

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

[0002] Chemical Mechanical Polishing (CMP) is known as a technology in the manufacturing process of semiconductor devices. Chemical Mechanical Polishing (CMP) is a technique that performs polishing by supplying a polishing solution containing abrasive particles, such as silica (SiO2), onto the polishing surface of a polishing pad and sliding a workpiece onto the polishing surface. A polishing device for performing this CMP is equipped with a polishing table that supports a polishing pad having a polishing surface, and a polishing head that presses the workpiece onto the polishing pad.

[0003] The grinding head is configured to press a workpiece against a grinding pad using an elastic membrane that forms a pressure chamber. Pressurized gas is supplied into the pressure chamber, and the pressure of the gas is applied to the workpiece through the elastic membrane. Therefore, the force with which the workpiece presses against the grinding pad can be controlled by the pressure within the pressure chamber. To efficiently transmit the gas pressure to the workpiece and to apply an appropriate force to the workpiece from its center to its ends, a flexible material such as rubber is generally used for the elastic membrane.

[0004] Typically, a workpiece needs to have a uniform film thickness distribution over its entire surface. Therefore, an elastic film forming multiple concentric pressure chambers has been used conventionally. When the initial film thickness along the radial direction of the workpiece is different, it is possible to control the polishing rate (also called the removal rate) along the radial direction of the workpiece by adjusting the pressure within the multiple pressure chambers. Prior art literature

[0005] Japanese Patent Publication No. 2010-274415 and Japanese Patent Publication No. 2013-111717 The problem to be solved

[0006] FIG. 10 is a cross-sectional view illustrating a portion of a grinding head (105) having an elastic membrane (130) that forms a plurality of pressure chambers (C1 to C6). The elastic membrane (130) has a contact portion (131) having a workpiece pressure surface (131a) that contacts a workpiece (W), and a partition wall (132 to 137) that extends upward from the contact portion (131) and forms pressure chambers (C1 to C6).

[0007] The bulkhead (132) is the outermost bulkhead and may also be referred to as a side wall. When gas is supplied to the pressure chamber (C1), if the bulkhead (132) comes into contact with the retainer ring (128), a change in the compressive force on the workpiece (W) occurs in the periphery of the workpiece (W). Therefore, the bulkhead (132) is required to have rigidity such that it does not collapse outwardly so as not to come into contact with the retainer ring (128) due to deformation of the elastic membrane (130). On the other hand, the bulkhead (132) is required to have flexibility such as extending downward when gas is supplied to the pressure chamber (C1).

[0008] The partitions (133 to 137) located further inward than the partition (132) are required to have flexibility such as extending downward when gas is supplied to the pressure chambers (C2 to C6). If the flexibility of the partitions (133 to 137) is insufficient, as shown in FIG. 10, the workpiece compression surface (131a) at the connection between the contact portion (131) and the partitions (133 to 137) is raised, and the compression force on the workpiece (W) is locally reduced.

[0009] The contact portion (131) is required to have appropriate rigidity so that it does not twist during the polishing of the workpiece (W), is resistant to wear due to friction with the workpiece (W), and is also resistant to the workpiece (W) easily detaching from the contact portion (131) after polishing. In this way, in order to realize a uniform film thickness distribution of the workpiece, appropriate rigidity or flexibility according to the function is required for each part of the elastic film.

[0010] Patent Document 1 describes a technique in which a diaphragm is provided on the substrate support side of an elastic film, and the gradient of polishing pressure (polishing speed) at the boundary of two adjacent areas is smoothed. Additionally, Patent Document 2 describes a technique in which the contact portion of an elastic film is reinforced with a resin plate or a polishing member to reduce contact between the elastic film and the retainer ring, and to prevent loosening at the contact portion or wrinkles on the contact surface. However, these techniques required providing a member other than the elastic material constituting the elastic film.

[0011] Therefore, the present invention aims to provide an elastic film capable of uniformly polishing a workpiece while having the required physical properties for each part of the elastic film, and a method for manufacturing such an elastic film. means of solving the problem

[0012] In one embodiment, an elastic membrane is provided for use in a grinding head for grinding a workpiece, and for pressing the workpiece into a grinding surface, and has a contact portion having a workpiece pressure surface for pressing the workpiece into the grinding surface, and a partition extending upward from the contact portion and forming a pressure chamber, wherein at least a portion of the contact portion and the partition is composed of a first rubber structure and a second rubber structure formed integrally, wherein the first rubber structure has a first hardness and the second rubber structure has a second hardness lower than the first hardness, the first rubber structure includes the workpiece pressure surface, and the second rubber structure includes at least a portion of the partition.

[0013] In one embodiment, the partition wall is connected to the outer edge of the contact portion, the first rubber structure comprises at least a portion of the lower part of the partition wall, and the second rubber structure comprises the upper part of the partition wall.

[0014] In one embodiment, the upper part of the bulkhead has a flexible portion configured to be expandable.

[0015] In one embodiment, the partition wall has a first partition wall and a second partition wall forming a plurality of pressure chambers, the first partition wall is connected to the outer edge of the contact portion, the second partition wall is located inwardly from the first partition wall, and the second rubber structure includes the second partition wall.

[0016] In one embodiment, the first rubber structure comprises at least a portion of the lower part of the first partition, and the second rubber structure comprises the upper part of the first partition.

[0017] In one embodiment, the upper part of the first bulkhead has a curved portion configured to be expandable.

[0018] In one embodiment, the first rubber structure and the second rubber structure have irregularities on the surface that forms the interface between the first rubber structure and the second rubber structure.

[0019] In one embodiment, a method for manufacturing an elastic membrane used in a grinding head for grinding a workpiece and for pressurizing the workpiece to a grinding surface is provided, comprising the steps of: molding one of a first rubber structure having a first hardness and 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, wherein the elastic membrane comprises a contact portion having a workpiece pressure surface for pressurizing the workpiece to a grinding surface, and a partition extending upward from the contact portion and forming a pressure chamber, wherein the first rubber structure includes the workpiece pressure surface and the second rubber structure includes at least a portion of the partition.

[0020] In one embodiment, the method for manufacturing an elastic membrane further includes a secondary vulcanization process of heating the integrally molded first rubber structure and the second rubber structure.

[0021] In one embodiment, in the process of forming the first rubber structure or the process of forming the second rubber structure, irregularities are formed on the surface that becomes the interface between the first rubber structure and the second rubber structure. Effects of the invention

[0022] According to the present invention, a uniform film thickness distribution of the workpiece can be realized by polishing the workpiece using an elastic film integrally formed with at least two rubber structures having different hardnesses for each part. Brief explanation of the drawing

[0023] FIG. 1 is a schematic diagram illustrating one embodiment of a grinding device. FIG. 2 is a cross-sectional view illustrating one embodiment of a grinding head. FIG. 3 is a cross-sectional view illustrating one embodiment of an elastic membrane. FIG. 4, FIG. 4 (a) to FIG. 4 (c), is a drawing illustrating an example of a method for manufacturing an elastic film. FIG. 5 is a drawing illustrating the continuation of FIG. 4 (c), FIG. 5 (a) and FIG. 5 (b). FIG. 6 is a flowchart of the manufacturing method illustrated in FIG. 4 (a) to FIG. 4 (c) and FIG. 5 (a) to FIG. 5 (b). FIG. 7, FIG. 7 (a) to FIG. 7 (c), are drawings illustrating different examples of methods for manufacturing an elastic membrane. FIG. 8 is a drawing illustrating the continuation of FIG. 7 (c), FIG. 8 (a) and FIG. 8 (b). FIG. 9 is a flowchart of the manufacturing method illustrated in FIG. 7 (a) to FIG. 7 (c) and FIG. 8 (a) to FIG. 8 (b). FIG. 10 is a cross-sectional view illustrating a part of a polishing head having an elastic membrane forming a plurality of pressure chambers. Specific details for implementing the invention

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0025] FIG. 1 is a schematic diagram illustrating one embodiment of a polishing device (1). The polishing device (1) is a device that chemically and mechanically polishes a workpiece (W), such as a wafer, substrate, or panel, used in the manufacture of a semiconductor device. As shown in FIG. 1, the polishing device (1) is equipped with 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).

[0026] The grinding table (3) is connected to a table motor (6) positioned below it via a table shaft (3a), and the table motor (6) is configured to rotate the grinding table (3) and the grinding pad (2) together in the direction indicated by the arrow. The surface of the grinding pad (2) forms a grinding surface (2a) for grinding the workpiece (W).

[0027] The grinding head (5) is configured to hold and support a workpiece (W) on its lower surface. The grinding head (5) is fixed to the end of the grinding head shaft (11), and the grinding head shaft (11) is rotatably supported by the head oscillating arm (13). The head oscillating arm (13) is rotatably supported by the support shaft (14). The grinding head shaft (11) is connected to a grinding head motor (not shown). The grinding head motor is configured to rotate the grinding head (5) together with the grinding head shaft (11) in the direction indicated by the arrow.

[0028] The grinding head shaft (11) is also connected to a grinding head vertical movement mechanism (not shown). The grinding head vertical movement mechanism is configured to move the grinding head shaft (11) and the grinding head (5) up and down relative to the head oscillating arm (13).

[0029] The polishing device (1) further comprises an operation control unit (20) that controls the operation of a polishing head (5), a table motor (6), a polishing head motor, a polishing head up-and-down movement mechanism, and a polishing liquid supply nozzle (8). The operation control unit (20) is composed of at least one computer.

[0030] A workpiece (W) is polished as follows. While rotating the polishing table (3) and the polishing head (5) in the direction indicated by the arrow in FIG. 1, polishing liquid is supplied from the polishing liquid supply nozzle (8) to the polishing surface (2a) of the polishing pad (2) on the polishing table (3). As the workpiece (W) is rotated by the polishing head (5), the workpiece (W) is pressed against the polishing surface (2a) of the polishing pad (2) by the polishing head (5) while the polishing liquid is 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 particles contained in the polishing liquid and / or the polishing pad (2).

[0031] Next, the grinding head (5) will be described. FIG. 2 is a cross-sectional view illustrating one embodiment of the grinding head (5). The grinding head (5) is equipped with a carrier (25) fixed to the end of the grinding head shaft (11), an elastic membrane (30) installed at 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). This retainer ring (28) is an annular structure that holds and supports the workpiece (W) so that the workpiece (W) does not protrude from the grinding head (5) during the grinding of the workpiece (W).

[0032] The elastic membrane (30) has a contact portion (31) having a workpiece pressure surface (31a) capable of contacting the upper surface of the workpiece (W), and partitions (32 to 37) extending 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 continuous walls arranged concentrically. The first partition (32) is the outermost partition. The first partition (32) may also be referred to as a side wall.

[0033] More specifically, the partitions (32 to 37) are a first partition (32) connected to the outer edge of the contact portion, a second partition (33) located further inside than the first partition (32), a third partition (34) located further inside than the second partition (33), a fourth partition (35) located further inside than the third partition (34), a fifth partition (36) located further inside than the fourth partition (35), and a sixth partition (37) located further inside than the fifth partition (36). The first partition (32) has a curved portion (32a) configured to be expandable on its upper side. The second partition (33) to the sixth partition (37) are extended obliquely upward in the radial direction from the contact portion (31).

[0034] The shape of the first partition (32) to the sixth partition (37) of the present invention is not limited to this embodiment. In one embodiment, the first partition (32) may not have a curved portion (32a) and may extend upward from the contact portion (31), or it may be branched into multiple sections while extending upward from the contact portion (31). In one embodiment, the second partition (33) to the sixth partition (37) may extend upward from the contact portion (31) without inclination, or it may be curved while extending upward from the contact portion (31).

[0035] Between the elastic membrane (30) and the carrier (25), six pressure chambers (C1 to C6) are provided. The pressure chambers (C1 to C6) are formed by at least the contact portion (31) of the elastic membrane (30) and partitions (32 to 37). Pressure chamber (C1) is located between the first partition (32) and the second partition (33), pressure chamber (C2) is located between the second partition (33) and the third partition (34), pressure chamber (C3) is located between the third partition (34) and the fourth partition (35), pressure chamber (C4) is located between the fourth partition (35) and the fifth partition (36), pressure chamber (C5) is located between the fifth partition (36) and the sixth partition (37), and pressure chamber (C6) is located within the sixth partition (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 one embodiment, the pressure chambers (C1 to C6) may have other shapes.

[0036] 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 one embodiment, the elastic membrane (30) may form fewer than six or more than six pressure chambers. That is, in one embodiment, fewer than six partitions may be provided, or more than six partitions may be provided. For example, only the first partition (32) may be provided, and the elastic membrane (30) may form only one pressure chamber (C1).

[0037] Gas transfer lines (F1, F2, F3, F4, F5, F6) are each connected to the pressure chambers (C1, C2, C3, C4, C5, C6). One end of each gas transfer line (F1 to F6) is connected to a compressed gas supply source (not shown) that serves as a utility supply source provided in a factory where the polishing device (1) is installed. Compressed gas, such as compressed air, is configured to be supplied to each of the pressure chambers (C1, C2, C3, C4, C5, C6) through the gas transfer lines (F1, F2, F3, F4, F5, F6).

[0038] Between the carrier (25) and the retainer ring (28), an annular rolling diaphragm (38) is disposed, and a pressure chamber (C7) is formed inside the rolling diaphragm (38). The pressure chamber (C7) is connected to the compressed gas supply source through 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 retainer ring (28) against the polishing surface (2a) of the polishing pad (2).

[0039] Gas transfer lines (F1 to F7) are extended via a rotary joint (18) installed on a grinding head shaft (11). Each gas transfer line (F1, F2, F3, F4, F5, F6, F7) communicating with pressure chambers (C1, C2, C3, C4, C5, C6, C7) is provided with a pressure regulator (R1, R2, R3, R4, R5, R6, R7). Compressed gas from a compressed gas supply source is supplied independently into each pressure chamber (C1 to C7) through the pressure regulators (R1 to R7). The pressure regulators (R1 to R7) are configured to regulate the pressure of the compressed gas within the pressure chambers (C1 to C7).

[0040] The pressure regulators (R1 to R7) can independently change the internal pressure of the pressure chambers (C1 to C7), thereby allowing the pressure force on the polishing pad (2) of the retainer ring (28) and the six corresponding regions of the workpiece (W) to be independently controlled. The region of the workpiece (W) corresponding to the pressure chamber (C1) is an annular region including the edge portion of the workpiece (W). The region of the workpiece (W) corresponding to the pressure chamber (C2) is an annular region that is inner 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 that is inner 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 that is inner than the region of the workpiece (W) corresponding to the pressure chamber (C3). The area of ​​the workpiece (W) corresponding to the pressure chamber (C5) is an annular area that is inner than the area of ​​the workpiece (W) corresponding to the pressure chamber (C4). The area of ​​the workpiece (W) corresponding to the pressure chamber (C6) is a circular area that is inner than the area of ​​the workpiece (W) corresponding to the pressure chamber (C5).

[0041] The gas transfer lines (F1 to F7) are each connected to an atmospheric opening valve (not shown), and it is also possible to open the pressure chambers (C1 to C7) to the atmosphere. The pressure regulators (R1 to R7) are connected to an operation control unit (20). The operation control unit (20) sends the respective target pressure values ​​of the pressure chambers (C1 to C7) to the pressure regulators (R1 to R7), and the pressure regulators (R1 to R7) operate so that the pressure inside the pressure chambers (C1 to C7) is maintained at the corresponding target pressure value.

[0042] The polishing head (5) can apply independent polishing pressure to each of multiple areas of the workpiece (W). For example, the polishing head (5) can press different areas of the surface of the workpiece (W) against the polishing surface (2a) of the polishing pad (2) with different polishing pressures. Accordingly, the polishing head (5) can control the film thickness profile of the workpiece (W) to achieve a target film thickness profile.

[0043] FIG. 3 is a cross-sectional view illustrating one embodiment of an elastic membrane (30). FIG. 3 illustrates a part 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 rubber having different hardness. More specifically, the elastic membrane (30) has a first rubber structure (41) having a first hardness and a 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 structures. Examples of elastic rubber constituting 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.

[0044] The first rubber structure (41) includes a lower contact portion (31b) having a workpiece pressure surface (31a). The lower contact portion (31b) is part of the contact portion (31), and more specifically, is the lower part of the contact portion (31). The first rubber structure (41) also includes a lower partition (32b) which is the lower part of the first partition (32). The lower partition (32b) forms the outer side of the lower part of the first partition (32) and extends upward from the lower contact portion (31b). The lower contact portion (31b) and the lower partition (32b) are integrally molded.

[0045] The second rubber structure (42) includes an upper contact portion (31c), an upper partition (32c), an inner wall portion (32d), and second partitions (33) through sixth partitions (37). The upper contact portion (31c) is part of the contact portion (31), and more specifically, the upper part of the contact portion (31) located on the lower contact portion (31b). The upper contact portion (31c) is thinner than the lower contact portion (31b). The upper partition (32c) forms the upper part of the first partition (32) and is located on the lower partition (32b). The upper partition (32c) has a curved portion (32a). The inner wall portion (32d) forms the lower inner side of the first partition (32) and extends upward from the upper contact portion (31c). The inner wall portion (32d) is located on the inner side of the lower partition (32b). The upper contact portion (31c), the upper partition (32c), the inner wall portion (32d), and the second partition (33) to the sixth partition (37) are integrally molded.

[0046] The first rubber structure (41) and the second rubber structure (42) are integrally molded and joined without using adhesive to form an integral structure. The surface that serves as 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 contact portion (31b) and the upper contact portion (31c) of the contact portion (31), and the interface between the lower partition (32b) and the inner wall portion (32d) of the first partition (32). By forming irregularities on the surface that serves as the interface, 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.

[0047] In one embodiment, the second rubber structure (42) may not have an upper contact portion (31c). In this case, the second partition (33) to the sixth partition (37) of the second rubber structure (42) extend upward from the contact portion (31) of the first rubber structure (41). Also, in one embodiment, the second rubber structure (42) may not have an inner wall portion (32d). In this case, the upper partition (32c) extends upward from the upper end of the lower partition (32b) of the first rubber structure (41).

[0048] According to the present embodiment, the elastic membrane (30) is provided with a first rubber structure (41) and a second rubber structure (42) having different hardnesses, so that it can have appropriate rigidity or flexibility depending on the physical properties required for each part 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. Accordingly, 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 thereto.

[0049] The first bulkhead (32) has different physical properties required at its upper and lower portions. The lower bulkhead (32b) is required to have appropriate rigidity so that it does not collapse outward and come into contact with the retainer ring (28) when gas is supplied to the pressure chamber (C1) (see FIG. 2). Since the lower bulkhead (32b) is composed of the first rubber structure (41), it has more rigidity than the second rubber structure (42). By doing so, contact between the lower bulkhead (32b) and the retainer ring (28) is prevented, and the pressure applied to the workpiece (W) can be made uniform.

[0050] The upper bulkhead (32c) is required to have appropriate flexibility so that it extends downward when gas is supplied to the pressure chamber (C1). Since the upper bulkhead (32c) is composed of a second rubber structure (42), it has more flexibility than the first rubber structure (41). Accordingly, the upper bulkhead (32c) expands and contracts according to the pressure of the gas supplied to the pressure chamber (C1), and the pressure on the workpiece (W) can be flexibly adjusted. Even if the lower bulkhead (32b) has relatively high hardness, the upper bulkhead (32c) expands and contracts, thereby allowing the pressure inside the pressure chamber (C1) to be properly transmitted to the outer edge of the workpiece (W). In particular, in this embodiment, the curved portion (32a), which is part of the upper bulkhead (32c), can improve the elasticity of the upper bulkhead (32c).

[0051] The second partition (33) to the sixth partition (37) is required to have flexibility such as extending downward when gas is supplied to the pressure chambers (C2 to C6) (see FIG. 2). Since the second partition (33) to the sixth partition (37) is composed of the second rubber structure (42), it has more flexibility than the first rubber structure (41). Accordingly, the second partition (33) to the sixth partition (37) extend flexibly according to the pressure of the gas supplied to the pressure chambers (C2 to C6) (see FIG. 2), and the elastic membrane (30) can press the workpiece (W) with an appropriate pressure.

[0052] Since the lower contact portion (31b) is composed of the first rubber structure (41), it has greater rigidity than the second rubber structure (42). Therefore, deformation of the upper side of the workpiece pressure surface (31a) at the connection portion between the second partition (33) to the sixth partition (37) and the contact portion (31) can be prevented, and localized reduction of the pressure force on the workpiece (W) can be prevented. In addition, when grinding the workpiece (W), the contact portion (31) is prevented from twisting due to the rotation of the grinding head (5) (see FIG. 1), and the contact portion (31) is less likely to wear out due to friction with the workpiece (W). Furthermore, after grinding, the workpiece (W) does not adhere to the contact portion (31) and is more likely to detach from the contact portion (31).

[0053] In this way, by using an elastic membrane (30) having different physical properties for each part, the polishing head (5) can polish the workpiece (W) with an appropriate pressure to achieve the target membrane thickness distribution of the workpiece (W). In addition, since the first rubber structure (41) and the second rubber structure (42) are integrally molded, there is no need to use an adhesive to fix the first rubber structure (41) and the second rubber structure (42) to each other. Therefore, appropriate rigidity or flexibility can be realized for each part without affecting the physical properties of the rubber constituting the elastic membrane (30).

[0054] Next, a method for manufacturing an elastic membrane (30) will be described. FIGS. 4 (a) to FIGS. 4 (c) and FIGS. 5 (a) to FIGS. 5 (b) are drawings illustrating an example of a method for manufacturing an elastic membrane (30). In the manufacturing method shown in FIGS. 4 (a) to FIGS. 4 (c) and FIGS. 5 (a) to FIGS. 5 (b), a first rubber structure (41) is first molded, and then a second rubber structure (42) is molded, so that the first rubber structure (41) and the second rubber structure (42) are integrally molded.

[0055] First, as shown in FIG. 4(a), a first rubber material (43), which is the material of the first rubber structure (41), is introduced into the space between the first molding mold (51) and the second molding mold (52). Then, as shown in FIG. 4(b), the first molding mold (51) and the second molding mold (52) are fitted together and the first rubber material (43) is pressed, causing the first rubber material (43) to fill the gap between the first molding mold (51) and the second molding mold (52). By heating the first rubber material (43) while it is pressed by the first molding mold (51) and the second molding mold (52), the first rubber structure (41) is formed.

[0056] In order to form irregularities on the surface that becomes the interface between the first rubber structure (41) and the second rubber structure (42), the second molding mold (52) may have irregularities on the surface (52a) that contacts the first rubber material (43). These irregularities are formed by surface roughening treatments such as embossing or blasting, for example. Due to the irregularities on the surface (52a), irregularities are formed 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 become the interface with the second rubber structure (42). By forming irregularities on the surface of the first rubber structure (41), the contact area between the first rubber structure (41) and the second rubber structure (42) is increased, and the first rubber structure (41) and the second rubber structure (42) can be more firmly integrated.

[0057] As shown in FIG. 4(c), the first rubber structure (41) formed by a method such as vacuum suction is held and supported in the first molding mold (51), and the second molding mold (52) is removed. In FIG. 4(c), the configuration of the vacuum suction mechanism is omitted. Next, the process of forming the second rubber structure (42) will be described.

[0058] As shown in FIG. 5(a), a second rubber material (44), which is the material of the second rubber structure (42), is introduced into the space between the first molding mold (51) and the third molding mold (53) in which the first rubber structure (41) is held and supported. The third molding mold (53) has a concave portion (53a) for forming partition walls (32 to 37) (see FIG. 3).

[0059] Next, as shown in FIG. 5(b), when the first molding mold (51) and the third molding mold (53) are fitted together and the second rubber material (44) is pressed, the second rubber material (44) enters the concave portion (53a) of the third molding mold (53). When the first molding mold (51) and the third molding mold (53) are fitted together, there is a gap (51a) of about 0.5 mm between the first rubber structure (41) held and supported by the first molding mold (51) and the third molding mold (53). The upper contact portion (31c) (see FIG. 3) of the second rubber structure (42) is formed by this gap (51a). By heating the second rubber material (44) while it is under pressure from the first molding mold (51) and the third molding mold (53), the second rubber structure (42) bonded to the first rubber structure (41) is molded, and the first rubber structure (41) and the second rubber structure (42) are integrally molded.

[0060] After that, the first rubber structure (41) and the second rubber structure (42) integrated from the first molding mold (51) and the third molding mold (53) are extracted. The third molding mold (53) may be composed of a combination of multiple molds, such as a core mold and a base mold, in order to extract the second rubber structure (42) having an intertwined shape.

[0061] 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 proceeded completely. By heating the integrally molded first rubber structure (41) and the second rubber structure (42), a secondary vulcanization is performed to further advance the cross-linking reaction between the first rubber material (43) and the second rubber material (44). In this secondary vulcanization process, as an example, the integrated first rubber structure (41) and the second rubber structure (42) are heated at 200°C for 3 to 4 hours using an oven (thermal device). By doing so, an elastic membrane (30) composed of the first rubber structure (41) and the second rubber structure (42) is completed.

[0062] FIG. 6 is a flowchart of the manufacturing method illustrated in FIG. 4 (a) to FIG. 4 (c) and FIG. 5 (a) to FIG. 5 (b).

[0063] In step S101, as shown in FIG. 4 (a), the first rubber material (43) is introduced into the space between the first molding mold (51) and the second molding mold (52).

[0064] In step S102, as shown in FIG. 4(b), the first molding mold (51) and the second molding mold (52) are fitted together to press the first rubber material (43), and the first rubber material (43) is heated to form the first rubber structure (41). After that, as shown in FIG. 4(c), the second molding mold (52) is removed.

[0065] In step S103, as shown in FIG. 5 (a), a second rubber material (44) is introduced into the space between the first molding mold (51) and the third molding mold (53).

[0066] In step S104, as shown in FIG. 5 (b), the first molding mold (51) and the third molding mold (53) are fitted together to press the second rubber material (44), and the second rubber material (44) is heated to form the second rubber structure (42) bonded to the first rubber structure (41), and the first rubber structure (41) and the second rubber structure (42) are integrally molded.

[0067] In step S105, the first rubber structure (41) and the second rubber structure (42) integrated from the first molding mold (51) and the third molding mold (53) are removed.

[0068] In step S106, a secondary vulcanization is performed to further advance the cross-linking reaction by heating the integrated first rubber structure (41) and the second rubber structure (42). By doing so, an elastic membrane (30) composed of the first rubber structure (41) and the second rubber structure (42) is completed.

[0069] According to the present embodiment, in order to mold a second rubber structure (42) bonded to a first rubber structure (41) before the cross-linking reaction is fully carried out (before secondary vulcanization), the first rubber structure (41) and the second rubber structure (42) can be integrated while carrying out the cross-linking reaction. In addition, since the process can be reduced compared to molding the first rubber structure (41) and the second rubber structure (42) separately and then bonding them, productivity can be improved.

[0070] FIGS. 7(a) to FIGS. 7(c) and FIGS. 8(a) to FIGS. 8(b) are drawings illustrating other examples of a method for manufacturing an elastic membrane (30). In the manufacturing method illustrated in FIGS. 7(a) to FIGS. 7(c) and FIGS. 8(a) to FIGS. 8(b), a second rubber structure (42) is first molded, and then a first rubber structure (41) is molded, so that the first rubber structure (41) and the second rubber structure (42) are integrally molded.

[0071] First, as shown in FIG. 7 (a), a second rubber material (44), which is the material of the second rubber structure (42), is introduced into the space between the first molding mold (54) and the second molding mold (55). The second molding mold (55) has a concave portion (55a) for forming partition walls (32 to 37) (see FIG. 3).

[0072] Next, as shown in FIG. 7(b), when the first molding mold (54) and the second molding mold (55) are fitted together and the second rubber material (44) is pressed, the second rubber material (44) enters the concave portion (55a) of the second molding mold (55). When the first molding mold (54) and the second molding mold (55) are fitted together, there is a gap (54a) of about 0.5 mm between the first molding mold (54) and the second molding mold (55). The upper contact portion (31c) (see FIG. 3) of the second rubber structure (42) is formed by this gap (54a). By heating the second rubber material (44) while it is pressed by the first molding mold (54) and the second molding mold (55), the second rubber structure (42) is formed.

[0073] In order to form irregularities on the surface that becomes the interface between the first rubber structure (41) and the second rubber structure (42), the first molding mold (54) may have irregularities on the surface (54b) that contacts the second rubber material (44). These irregularities are formed by surface roughening treatments such as embossing or blasting, for example. Due to the irregularities on the surface (54b), irregularities are formed on the surface of the upper contact portion (31c) and the inner wall portion (32d) (see FIG. 3) of the second rubber structure (42) that becomes the interface with the first rubber structure (41). By forming irregularities on the surface of the second rubber structure (42), the contact area between the first rubber structure (41) and the second rubber structure (42) is increased, and the first rubber structure (41) and the second rubber structure (42) can be more firmly integrated.

[0074] As shown in FIG. 7(c), the first molding mold (54) is removed while the second rubber structure (42) is held and supported by the second molding mold (55). Next, the process of molding the first rubber structure (41) is described.

[0075] As shown in FIG. 8(a), the first rubber material (43), which is the material of the first rubber structure (41), is introduced into the space between the second molding mold (55) and the third molding mold (56) in which the second rubber structure (42) is supported. Then, as shown in FIG. 8(b), the first rubber material (43) is pressed by fitting the second molding mold (55) and the third molding mold (56) together, and the first rubber material (43) fills the gap between the second molding mold (55) and the third molding mold (56). By heating the first rubber material (43) while it is pressed by the second molding mold (55) and the third molding mold (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 integrally molded.

[0076] After that, the first rubber structure (41) and the second rubber structure (42) integrated from the second molding mold (55) and the third molding mold (56) are extracted. The second molding mold (55) may be composed of a combination of multiple molds, such as a core mold and a base mold, in order to extract the second rubber structure (42) having an intertwined shape.

[0077] 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 proceeded completely. By heating the integrally molded first rubber structure (41) and the second rubber structure (42), a secondary vulcanization is performed to further proceed the cross-linking reaction between the first rubber material (43) and the second rubber material (44). In this process, as an example, the first rubber structure (41) and the second rubber structure (42) are heated at 200°C for 3 to 4 hours using an oven (thermal device). By doing so, an elastic membrane (30) composed of the first rubber structure (41) and the second rubber structure (42) is completed.

[0078] FIG. 9 is a flowchart of the manufacturing method illustrated in FIG. 7 (a) to FIG. 7 (c) and FIG. 8 (a) to FIG. 8 (b).

[0079] In step S201, as shown in FIG. 7 (a), a second rubber material (44) is introduced into the space between the first molding mold (54) and the second molding mold (55).

[0080] In step S202, as shown in FIG. 7(b), the first molding mold (54) and the second molding mold (55) are fitted together to press the second rubber material (44), and the second rubber material (44) is heated to form the second rubber structure (42). After that, as shown in FIG. 7(c), the first molding mold (54) is removed.

[0081] In step S203, as shown in FIG. 8 (a), the first rubber material (43) is introduced into the space between the second molding mold (55) and the third molding mold (56).

[0082] In step S204, as shown in FIG. 8 (b), the first rubber material (43) is pressed by fitting the second molding mold (55) and the third molding mold (56) together, and the first rubber material (43) is heated to form the first rubber structure (41) bonded to the second rubber structure (42), and the first rubber structure (41) and the second rubber structure (42) are integrally molded.

[0083] In step S205, the first rubber structure (41) and the second rubber structure (42) integrated from the second molding mold (55) and the third molding mold (56) are removed.

[0084] In step S206, a secondary vulcanization is performed to further advance the cross-linking reaction by heating the integrated first rubber structure (41) and the second rubber structure (42). By doing so, an elastic membrane (30) composed of the first rubber structure (41) and the second rubber structure (42) is completed.

[0085] According to the present embodiment, in order to mold the first rubber structure (41) bonded to the second rubber structure (42) before the cross-linking reaction is fully carried out (before secondary vulcanization), the first rubber structure (41) and the second rubber structure (42) can be integrated while carrying out the cross-linking reaction. In addition, since the process can be reduced compared to molding the first rubber structure (41) and the second rubber structure (42) separately and then bonding them, productivity can be improved.

[0086] In this embodiment, the elastic membrane (30) is composed of rubber having two types of hardness, such as the first rubber structure (41) and the second rubber structure (42), but in one embodiment, the elastic membrane (30) may be composed of a material having three or more types of hardness. For example, the upper partition (32c) of the first partition (32) and the second partition (33) to the sixth partition (37) may be formed of rubber structures having different hardness.

[0087] 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, they may be rubber structures with different physical properties such as tensile strength, elongation, and elastic modulus other than hardness.

[0088] The above-described embodiments are described for the purpose of enabling a person skilled in the art to practice the present invention. Various modifications of the above embodiments are naturally achievable by those skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments but is interpreted within the broadest scope of the technical concept defined by the claims. Explanation of the symbols

[0089] 1: Grinding device 2: Polishing pad 2a: Polished surface 3: Grinding table 3a: Table axis 5: Grinding head 6: Table motor 8: Polishing fluid supply nozzle 11: Grinding head shaft 13: Head oscillating arm 14: Support axis 18: Rotary joint 20: Operation control unit 25: Carrier 28: Retainer ring 30: Elastic membrane 31: Contact part 31a: Workpiece compression surface 31b: Lower contact part 31c: Upper contact part 32: 1st bulkhead 32a: Curved part 32b: Lower bulkhead 32c: Upper bulkhead 32d: Inner wall 33: Second bulkhead 34: Third bulkhead 35: 4th bulkhead 36: Fifth 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: First molding type 52, 55: Second molding 53, 56: Third molding C1 to C7: Pressure chambers F1 to F7: Gas transfer lines R1 to R7: Pressure regulators

Claims

Claim 1 An elastic membrane used in a polishing head for chemical mechanical polishing of a workpiece, for pressurizing the workpiece onto the polishing surface of a polishing pad, and comprising a contact portion having a workpiece pressure surface capable of contacting the upper surface of the workpiece, and a partition extending upward from the contact portion and forming a pressure chamber, wherein at least a portion of the contact portion and the partition is composed of a first rubber structure and a second rubber structure formed integrally, wherein the first rubber structure has a first hardness, and the second rubber structure has a second hardness lower than the first hardness, wherein the workpiece pressure surface is composed of the first rubber structure, the outer side of the lower portion of the partition is composed of the first rubber structure, and the inner side of the lower portion of the partition is composed of the second rubber structure, wherein the upper portion of the partition is composed of the second rubber structure, and the upper portion of the partition has a bend portion configured to be elastic, wherein the bend portion is composed of the second rubber structure, and furthermore, the first rubber An elastic membrane located above the structure. Claim 2 An elastic membrane according to claim 1, wherein the partition is connected to the outer edge of the contact portion, the outer side of the lower portion of the partition is composed of the first rubber structure, and the inner side of the lower portion of the partition is composed of the second rubber structure. Claim 3 In claim 1, the bulkhead has a first bulkhead and a second bulkhead forming a plurality of pressure chambers, the first bulkhead is connected to the outer edge of the contact portion, the second bulkhead is located inwardly from the first bulkhead and is composed of the second rubber structure, and the bend is an elastic membrane located on the upper part of the first bulkhead. Claim 4 In paragraph 3, the outer side of the lower portion of the first partition is composed of the first rubber structure, the inner side of the lower portion of the first partition is composed of the second rubber structure, and the upper portion of the first partition is composed of the second rubber structure, forming an elastic membrane. Claim 5 In any one of claims 1 to 4, the first rubber structure and the second rubber structure are elastic membranes having irregularities on the surface that forms the interface between the first rubber structure and the second rubber structure. Claim 6 A method for manufacturing an elastic membrane used in a polishing head for chemical mechanical polishing of a workpiece, for pressurizing the workpiece onto the polishing surface of a polishing pad, comprising: molding one of a first rubber structure having a first hardness and 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 form the first rubber structure and the second rubber structure. The elastic membrane comprises a contact portion having a workpiece pressure surface capable of contacting the upper surface of the workpiece, and a partition extending upward from the contact portion and forming a pressure chamber. The workpiece pressure surface is composed of the first rubber structure, the outer side of the lower portion of the partition is composed of the first rubber structure, the inner side of the lower portion of the partition is composed of the second rubber structure, and the upper portion of the partition is composed of the second rubber structure. A method for manufacturing an elastic membrane, wherein the upper portion of the above partition wall is configured to have a flexible portion configured to be expandable, and the portion is configured to be a second rubber structure and is also located above the first rubber structure. Claim 7 A method for manufacturing an elastic membrane according to claim 6, further comprising a secondary vulcanization process for heating the integrally molded first rubber structure and the second rubber structure. Claim 8 A method for manufacturing an elastic membrane according to claim 6 or 7, wherein in the process of forming the first rubber structure or the process of forming the second rubber structure, irregularities are formed on the surface that becomes the interface between the first rubber structure and the second rubber structure. Claim 9 delete Claim 10 delete

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