Carrier head

Abstract

A carrier head is disclosed. A carrier head according to one embodiment comprises: a head member; a membrane connected to the head member to form a pressure chamber and gripping a substrate through a gripping surface; a retainer ring connected to the head member to surround the perimeter of the substrate gripped by the membrane; and a pusher connected to the membrane and pressing the substrate in a dechucking direction away from the membrane while the substrate is gripped by the membrane, wherein the pusher may be switchable between a first state in which the substrate is not pressed and a second state in which the substrate is pressed in the dechucking direction.

Description

Technology Field

[0001] The following embodiment relates to a carrier head. Background Technology

[0002] The manufacturing of semiconductor devices requires chemical mechanical polishing (CMP) operations, including polishing, buffing, and cleaning. Semiconductor devices are in the form of a multilayer structure, and transistor devices with diffusion regions are formed on the substrate layer. On the substrate layer, connecting metal lines are patterned and electrically connected to the transistor devices forming the functional components. As is known, the patterned conductive layer is insulated from other conductive layers by an insulating material such as silicon dioxide. As more metal layers and associated insulating layers are formed, the need to flatten the insulating material increases. If flattening is not performed, the fabrication of additional metal layers becomes substantially more difficult due to significant variations in surface morphology. Furthermore, since the metal line pattern is formed with an insulating material, metal CMP operations are performed to remove excess metal.

[0003] Meanwhile, after the CMP operation is completed, it is necessary to dechux the substrate from the carrier head. During this process, air is introduced between the membrane and the substrate. Conventionally, a method was used to introduce air by applying different pressures to each pressure chamber formed by the membrane to create a small gap between the membrane and the substrate. However, this method had the problem that it took a long time to dechux the substrate from the carrier head. Therefore, there is a need for a carrier head capable of rapidly dechuxing the substrate after the CMP operation is completed.

[0004] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the content of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application. The problem to be solved

[0005] The objective according to one embodiment is to provide a carrier head that rapidly dechuxes a substrate.

[0006] The objective according to one embodiment is to provide a carrier head that safely dechuxes a substrate. means of solving the problem

[0007] A carrier head according to one embodiment comprises, in the carrier head: a head member; a membrane connected to the head member to form a pressure chamber and gripping a substrate through a gripping surface; a retainer ring connected to the head member to surround the perimeter of the substrate gripped by the membrane; and a pusher connected to the membrane and pressing the substrate in a dechucking direction away from the membrane while the substrate is gripped by the membrane, wherein the pusher may be switchable between a first state in which the substrate is not pressed and a second state in which the substrate is pressed in the dechucking direction.

[0008] A carrier head according to one embodiment may include a tube disposed on the gripping surface of the membrane, the pusher, and a pump that injects or sucks air into the tube to expand or compress the tube.

[0009] In a carrier head according to one embodiment, the pusher may be provided in multiple numbers.

[0010] In one embodiment of the carrier head, at least one of the plurality of pushers may be positioned at a location adjacent to the edge of the membrane rather than the center of the membrane.

[0011] In a carrier head according to one embodiment, the distance of each of the plurality of pushers from the center of the membrane may be different from each other.

[0012] A carrier head according to one embodiment can sequentially switch from a first state to a second state starting from a pusher located at a distance from the center of the substrate.

[0013] A carrier head according to one embodiment may have a plurality of pushers, wherein the pushers include a first pusher, a second pusher, and a third pusher, wherein the first pusher is positioned at a first point spaced apart by a first distance from the center of the membrane, the second pusher is positioned at a second point spaced apart by a second distance from the center of the membrane, and the third pusher is positioned at a third point spaced apart by a third distance from the center of the membrane.

[0014] In a carrier head according to one embodiment, the second distance and the third distance may be formed such that they are equal to each other and each is longer than the first distance.

[0015] In a carrier head according to one embodiment, in the second state, the lengths of the second pusher and the third pusher in the dechucking direction may be formed to be longer than the length of the first pusher in the dechucking direction.

[0016] In one embodiment, the carrier head may be formed such that, in the second state, each of the first pusher, the second pusher, and the third pusher includes a curved surface to contact the substrate.

[0017] In a carrier head according to one embodiment, the pusher may be formed to contact the membrane at a first edge perpendicular to the diameter direction of the membrane and a second edge spaced apart from the first edge by a fourth distance along the diameter direction of the membrane.

[0018] In the second state, the carrier head according to one embodiment may have a length in the thickness direction of the membrane along the diameter direction of the membrane.

[0019] In the carrier head according to one embodiment, in the second state, the pusher may be formed such that a cross-section perpendicular to the lower surface of the membrane includes a triangular shape.

[0020] In one embodiment, the carrier head, in the second state, may have a length of 1 cm or more and 2 cm or less in the thickness direction of the membrane at the second edge.

[0021] A carrier head according to one embodiment may be formed such that the first edge penetrates the center of the membrane. Effects of the invention

[0022] A carrier head according to one embodiment can quickly dechux a substrate.

[0023] A carrier head according to one embodiment can safely dechux a substrate.

[0024] The effects of the carrier head according to one embodiment are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view of a substrate polishing device according to one embodiment. FIG. 2 is a cross-sectional view of a carrier head (1) in a second state according to one embodiment. FIG. 3a is a perspective view of the membrane (12) in a first state according to one embodiment. FIG. 3b is a plan view of the membrane (12) in a second state according to one embodiment. FIG. 4a is a perspective view of the membrane (12) and pusher (14) in a second state according to one embodiment. FIG. 4b is a plan view of the membrane (12) and pusher (14) in a second state according to one embodiment. FIG. 4c is a plan view of the membrane (12) and the pusher (14) in a second state according to one embodiment. FIG. 5a is a perspective view of the membrane (12') and the pusher (14') in a second state according to one embodiment. FIG. 5b is a plan view of the membrane (12') and pusher (14') in a second state according to one embodiment. FIG. 5c is a plan view of the membrane (12') and the pusher (14') in a second state according to one embodiment. Specific details for implementing the invention

[0026] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0027] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0030] In addition, when describing with reference to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. In describing the embodiments, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the embodiments, such detailed description is omitted.

[0031] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments. These terms are intended only to distinguish the components from other components, and the nature, order, or sequence of the components is not limited by these terms. Where it is stated that a component is "connected," "combined," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but that another component may also be "connected," "combined," or "connected" between each component.

[0032] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the description in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0034] FIG. 1 is a perspective view of a substrate polishing device according to one embodiment.

[0035] Referring to FIG. 1, a substrate polishing device according to one embodiment can be used in a chemical mechanical planarization (CMP) process of a substrate (S).

[0036] The substrate (S) that is polished through the substrate polishing device may be a silicon wafer for manufacturing a semiconductor device. However, the type of substrate (S) is not limited to this. For example, the substrate (S) may be glass for a flat panel display device (FPD), such as a liquid crystal display (LCD) or a plasma display panel (PDP).

[0037] A substrate polishing device can polish a substrate (S). The substrate polishing device may include a polishing unit (10) and a carrier head (1).

[0038] The polishing unit (10) can physically polish the surface to be polished of the substrate (S). The polishing unit (10) may include a polishing plate (112) and a polishing pad (111).

[0039] A polishing pad (111) may be connected to the polishing plate (112). For example, a polishing pad (111) may be attached to the upper part of the polishing plate (112). The polishing plate (112) can polish the surface to be polished of a substrate (S) in contact with the polishing pad (111) while rotating around an axis. The polishing plate (112) can move in an up-and-down direction (e.g., z-direction). Through the up-and-down movement of the polishing plate (112), the relative position of the polishing pad (111) with respect to the ground can be adjusted. With the substrate (S) in contact with the polishing pad (111), the frictional force between the substrate (S) and the polishing pad (111) can be adjusted through the up-and-down movement of the polishing plate (112).

[0040] The polishing pad (111) is in direct contact with the surface to be polished of the substrate (S) and can perform the function of physically abrading the surface to be polished of the substrate (S). The polishing pad (111) may include a polyurethane material.

[0042] FIG. 2 is a cross-sectional view of a carrier head (1) in a second state according to one embodiment.

[0043] Referring to FIG. 2, a carrier head (1) according to one embodiment can dechux a substrate (S) in a second state.

[0044] In one embodiment, the carrier head (1) can chuck and grip a substrate (S) to be polished and move the gripped substrate (S) to a polishing position. The carrier head (1) can perform polishing of the substrate (S) by bringing the gripped substrate (S) into contact with a polishing pad (111). While the substrate (S) is in contact with the polishing pad (111), the carrier head (1) can control the frictional force acting between the substrate (S) and the polishing pad (111) by pressing the substrate (S) in the direction of the polishing pad (111) (e.g., -z direction). The carrier head (1) can perform the function of maintaining the state in which the substrate (S) is in contact with the polishing pad (111) during the polishing process of the substrate (S). The carrier head (1) may include a head member (11), a membrane (12), a retainer ring (13), and a pusher (14).

[0045] In one embodiment, the head member (11) can adjust the position of the substrate (S). The head member (11) receives power from the outside and can rotate around an axis perpendicular to the surface of the polishing pad (111). Depending on the rotation of the head member (11), the gripped substrate (S) can be polished while rotating in contact with the polishing pad (111).

[0046] The head member (11) can move the substrate (S) horizontally. For example, the head member (11) can translate in a first direction (e.g., x direction and / or y direction) parallel to the surface of the polishing pad (111) and in a second direction (e.g., z direction) perpendicular to the first direction. Through combined movement in the first and second directions, the head member (11) can move the substrate (S) in a plane parallel to the surface of the polishing pad (111). Consequently, depending on the horizontal movement of the head member (11), the substrate (S) can be transferred to a polishing position or removed from a polishing position.

[0047] The head member (11) can move the substrate (S) in an up-and-down direction (e.g., z-direction) relative to the ground. The head member (11) can move in an up-and-down direction (e.g., z-direction) relative to a substrate storage unit (not shown) for chucking and de-chucking the substrate (S), or move in an up-and-down direction (e.g., z-direction) relative to a polishing pad (111) for polishing the substrate (S).

[0048] In one embodiment, the membrane (12) is connected to the head member (11) and can apply pressure to the substrate (S). The membrane (12) can form a plurality of pressure chambers (C). The pressure of each pressure chamber (C) can be individually controlled. Depending on the pressure fluctuation of the pressure chamber (C), the pressure applied to the portion of the substrate (S) facing each pressure chamber (C) can be locally controlled. For example, if the pressure inside the pressure chamber (C) rises, the corresponding portion of the substrate (S) can be pressed by the membrane (12) to adhere more strongly to the polishing pad (111). The membrane (12) may include a bottom plate forming the bottom surface of the pressure chamber (C) and flaps forming the sides of the pressure chamber (C). Multiple flaps may be formed to have different radii relative to the center of the bottom plate. In this case, the space between adjacent flaps may form each pressure chamber (C).

[0049] In one embodiment, the retainer ring (13) may be connected to the head member (11) to surround the perimeter of the gripped substrate (S). The retainer ring (13) can prevent the substrate (S) from moving away from the position where it is gripped, that is, from the lower side of the membrane (12). During the polishing process of the substrate (S), vibration may be transmitted to the substrate (S) due to contact between the head member (11) and the polishing pad (111). In this case, the retainer ring (13) can support the outer side of the substrate (S) so that the substrate (S) does not move away from the carrier head (1) due to vibration.

[0050] In one embodiment, the pusher (14) can press the substrate (S) in a dechucking direction away from the membrane (12) while the substrate (S) is held in the membrane (12). In one embodiment, the pusher (14) can be connected to the membrane (12). Hereinafter, the state in which the pusher (14) does not press the substrate (S) is referred to as the first state, and the state in which the pusher (14) presses the substrate (S) in a dechucking direction (e.g., -z direction) is referred to as the second state. In one embodiment, the pusher (14) can be switched between the first state and the second state. Accordingly, when switching from the first state to the second state, air is introduced between the membrane (12) and the substrate (S), so that the substrate (S) can be dechucking from the membrane (12).

[0051] In one embodiment, the pushers (14) may be provided in multiple numbers. For example, at least one of the multiple pushers (14) may be positioned closer to the edge of the membrane (12) than to the center of the membrane (12). Thus, the pushers (14) can stably and efficiently dechucking the substrate (S) from the membrane (12). However, this is exemplary, and the number and arrangement of the pushers (14) are not limited thereto. Additionally, for example, the distance of each of the multiple pushers (14) from the center of the membrane (12) may be arranged to be different from one another. Thus, the pushers (14) can dechucking the substrate (S) from the membrane (12) in response to various shapes of the substrate (S). However, this is exemplary, and the arrangement of the pushers (14) is not limited thereto. Additionally, for example, the first state can be transitioned sequentially from the first state to the second state starting from the pusher (14) located at a distance from the center of the substrate (S). Thus, the pusher (14) can dechux the substrate (S) from the membrane (12) with minimal pressure, and damage to the substrate (S) during the dechuxing process can be minimized. However, this is exemplary, and the sequence of transition from the first state to the second state of the pusher (14) is not limited thereto.

[0052] In one embodiment, the pusher (14) may include a tube (141) and a pump (142). In one embodiment, the tube (141) is positioned on the gripping surface of the membrane (12) and may come into contact with the substrate (S). In a first state, the tube (141) may be compressed by the pump (142) so as not to protrude from the membrane (12) in the dechucking direction (e.g., -z direction). Additionally, in a second state, the tube (141) may be expanded by the pump (142) so as to protrude from the membrane (12) in the dechucking direction (e.g., -z direction). For example, the pump (142) may be formed of a soft material such as rubber. Thus, when transitioning from the first state to the second state, the pump (142) may not damage the substrate (S). However, this is exemplary, and the material of the pump (142) is not limited thereto. For example, the pump (142) may be formed of plastic. In one embodiment, the pump (142) may inject or suck air into the tube (141) to expand or compress the tube (141). For example, the pump (142) may be positioned outside the head member, and the pump (142) and the tube (141) may be connected by a connecting pipe. Additionally, for example, the connecting pipe may be connected to the tube (141) by penetrating the membrane (12). Thus, the pump (142) may inject or suck air into the tube (141) through the connecting pipe. However, this is exemplary, and the placement of the pump (142) is not limited thereto. For example, the pump (142) may be positioned inside the carrier member to inject or suck air into the tube (141).

[0054] FIG. 3a is a perspective view of the membrane (12) in a first state according to one embodiment, and FIG. 3b is a plan view of the membrane (12) in a second state according to one embodiment.

[0055] Referring to FIGS. 3a and FIGS. 3b, in the first state, the membrane (12) can chuck the substrate (S).

[0056] In one embodiment, in the first state, the pusher (e.g., the pusher (14) of FIG. 2) may not press the substrate (S). In the first state, the pusher (14) does not protrude from the lower surface of the membrane (12), so that no space is formed between the membrane (12) and the substrate (S), and an adhesive force may be formed between the membrane (12) and the substrate (S). At this time, if the adhesive force between the membrane (12) and the substrate (S) is greater than the gravitational force acting on the substrate (S), the state in which the substrate (S) is chucked from the membrane (12) may be maintained.

[0058] FIG. 4a is a perspective view of the membrane (12) and pusher (14) in a second state according to one embodiment, FIG. 4b is a plan view of the membrane (12) and pusher (14) in a second state according to one embodiment, and FIG. 4c is a plan view of the membrane (12) and pusher (14) in a second state according to one embodiment.

[0059] Referring to FIGS. 4a to 4c, a pusher (14) according to one embodiment can dechux a substrate (S) from a membrane (12) in a second state.

[0060] In one embodiment, the pusher (14) may include a first pusher (14a), a second pusher (14b), and a third pusher (14c). In one embodiment, the first pusher (14a) may be positioned at a first point (P1) spaced apart by a first distance (L1) from the center of the membrane (12), the second pusher (14b) may be positioned at a second point (P2) spaced apart by a second distance (L2) from the center of the membrane (12), and the third pusher (14c) may be positioned at a third point (P3) spaced apart by a third distance (L3) from the center of the membrane (12). For example, the first pusher (14a), the second pusher (14b), and the third pusher (14c) may be positioned such that the second distance (L2) and the third distance (L3) are equal to each other and are each longer than the first distance (L1). However, this is exemplary and the arrangement of each pusher (14) is not limited thereto.

[0061] In one embodiment, in the second state, the first pusher (14a), the second pusher (14b), and the third pusher (14c) can press the substrate (S) from the membrane (12) in the dechucking direction (e.g., -z direction). For example, in the second state, the lengths (D2, D3) of the second pusher and the third pusher in the dechucking direction (e.g., -z direction) can be formed to be longer than the length (D1) of the first pusher in the dechucking direction (e.g., -z direction). Thus, in the second state, the first pusher (14), the second pusher (14b), and the third pusher (14c) can all come into contact with the substrate (S). However, this is exemplary, and the lengths (D1, D2, D3) of each pusher (14) in the dechucking direction (e.g., -z direction) in the second state are not limited thereto. Additionally, for example, in the second state, each of the first pusher (14a), the second pusher (14b), and the third pusher (14c) may be formed to include a curved surface. For example, in the second state, each pusher (14) may include a semicircular cross-section with respect to a vertical plane (e.g., the yz plane). Thus, in the second state, each pusher (14) may come into contact with the substrate (S). As a result, in the second state, the substrate (S) can be dechucking from the membrane (12) without damaging the substrate (S).

[0063] FIG. 5a is a perspective view of the membrane (12') and pusher (14') in a second state according to one embodiment, FIG. 5b is a plan view of the membrane (12') and pusher (14') in a second state according to one embodiment, and FIG. 5c is a plan view of the membrane (12') and pusher (14') in a second state according to one embodiment.

[0064] Referring to FIGS. 5a to 5c, a pusher (14') according to one embodiment can dechux the substrate (S) from the membrane (12') in a second state.

[0065] In one embodiment, the contact surface between the pusher (14') and the membrane (12') may be formed as a rectangle. In one embodiment, the pusher (14') may be formed to contact the membrane (12') at a first edge (E1) perpendicular to the diameter direction (e.g., y-direction) of the membrane (12') and at a second edge (E2) spaced apart from the first edge (E1) by a fourth distance (L4) along the diameter direction (e.g., y-direction) of the membrane (12'). For example, the contact surface between the pusher (14') and the membrane (12') may be formed as a right-angled rectangle. However, this is exemplary and is not limited thereto. For example, the contact surface between the pusher (14') and the membrane (12') may be formed as a trapezoid, and may also be formed as a polygon or include a curved surface.

[0066] In one embodiment, in a second state, the pusher (14') can press the substrate (S) from the membrane (12') in a dechucking direction (e.g., -z direction). For example, in the second state, the pusher (14') can be formed so that its length in the thickness direction (e.g., z direction) of the membrane (12') is extended along the diameter direction (e.g., y direction) of the membrane (12'). Additionally, for example, in the second state, the pusher (14') can be formed to include a triangular cross-section with respect to a plane perpendicular to the lower surface of the membrane (12') (e.g., yz plane). Thus, in the second state, the pusher (14') can press the substrate (S) from the outside of the substrate (S) in a dechucking direction (e.g., -z direction) and can separate the substrate (S) from the membrane (12') with a minimum pressure. However, this is exemplary, and the shape of the pusher (14') in the second state is not limited thereto. For example, in the second state, the pusher (14') may be formed with a length of 1 cm or more and 2 cm or less in the thickness direction (e.g., z-direction) of the membrane (12') at the second edge (E2). Additionally, for example, the first edge (E1) may be formed to penetrate the center of the membrane (12'). However, this is exemplary, and the arrangement and shape of the pusher (14') are not limited thereto.

[0068] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0069] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below. Explanation of the symbols

[0070] 1: Carrier head 10: Grinding Unit 11: Head member 12: Membrane 13: Retainer ring 14: Pusher

Claims

Claim 1 A carrier head comprises: a head member; a membrane connected to the head member to form a pressure chamber and gripping a substrate through a gripping surface; and a retainer ring connected to the head member to surround the perimeter of the substrate gripped by the membrane. A carrier head comprising a tube connected to the membrane so as to be disposed on the gripping surface of the membrane, and a pusher including a pump connected to the tube through a connecting pipe penetrating the membrane and injecting or sucking air into the tube to expand or compress the tube, wherein the pusher is connected to the membrane and configured to press the substrate in a dechucking direction away from the membrane while the substrate is gripped by the membrane, and wherein the pusher is switchable between a first state in which the tube is compressed by the pump and does not protrude from the gripping surface of the membrane so as not to press the substrate, and a second state in which the tube is expanded by the pump and protrudes from the lower surface of the membrane so as to press the substrate in the dechucking direction, wherein the pusher is provided in a plurality of units, and the distance of each tube of the plurality of pushers relative to the center of the membrane is different from each other. Claim 2 delete Claim 3 delete Claim 4 In claim 1, at least one of the tubes of the plurality of pushers is a carrier head positioned at a location adjacent to the edge of the membrane rather than the center of the membrane. Claim 5 delete Claim 6 In claim 1, the carrier head wherein the plurality of pushers is sequentially switched from a first state to a second state starting from the tube of the pusher located at a distance from the center of the substrate. Claim 7 A carrier head according to claim 1, wherein the plurality of pushers comprises a first pusher, a second pusher, and a third pusher, wherein the tube of the first pusher is positioned at a first point spaced apart by a first distance from the center of the membrane, the tube of the second pusher is positioned at a second point spaced apart by a second distance from the center of the membrane, and the tube of the third pusher is positioned at a third point spaced apart by a third distance from the center of the membrane. Claim 8 In claim 7, the second distance and the third distance are identical to each other and are each formed to be longer than the first distance, a carrier head. Claim 9 In claim 8, a carrier head formed such that, in the second state, the lengths of the tubes of the second pusher and the third pusher in the dechucking direction are longer than the lengths of the tubes of the first pusher in the dechucking direction. Claim 10 In claim 9, in the second state, the tubes of the first pusher, the second pusher, and the third pusher are formed to include a curved surface to contact the substrate, the carrier head. Claim 11 In claim 1, the tube of the pusher is formed to contact the membrane at a first edge perpendicular to the diameter direction of the membrane and a second edge spaced apart from the first edge by a fourth distance along the diameter direction of the membrane, forming a carrier head. Claim 12 In claim 11, in the second state, the tube of the pusher is a carrier head in which the length in the thickness direction of the membrane increases along the diameter direction of the membrane. Claim 13 In claim 12, in the second state, the tube of the pusher is formed such that the cross-section perpendicular to the lower surface of the membrane includes a triangular shape, forming a carrier head. Claim 14 In claim 11, in the second state, the tube of the pusher is formed such that, at the second edge, the length in the thickness direction of the membrane is 1 cm or more and 2 cm or less, forming a carrier head. Claim 15 In claim 11, a carrier head formed such that the first edge penetrates the center of the membrane.

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