Laminate, polishing pad fixation method, foam, and laminated sheet

Abstract

A purpose of the present invention is to provide a laminate that makes it possible to improve polishing accuracy and yield in a polishing step. Another purpose of the present invention is to provide a polishing pad fixation method in which said laminate is used, and a foam and a laminated sheet which can be used in said laminate. The present invention is a laminate used for fixing a polishing pad and the surface plate of a polishing machine via bonding in a polishing step. The laminate comprises: a foam; a first adhesive layer which is on one surface of the foam and which is to be bonded to the polishing pad; and a second adhesive layer which is on another surface of the foam and which is to be bonded to the surface plate of the polishing machine. The foam has a 25% compressive strength of 0.18-3.5 MPa and a Shore A hardness of 45-100, and has a first feature or a second feature. The first feature is that the foam includes a polyolefin foam, and the density of the foam is 185-500 kg / m3 <sp / >. The second feature is that the foam includes at least one foam selected from the group consisting of polyurethane foams, rubber foams, and acrylic foams.

Description

Laminate, method for fixing polishing pad, foam, and laminate sheet

[0001] The present invention also relates to a method for fixing a polishing pad, a foam, and a laminate sheet.

[0002] In processes for polishing semiconductor wafers, liquid crystal glass substrates, and the like to a predetermined thickness (e.g., chemical-mechanical-polishing (CMP) processes), polishing is performed using a polishing cloth or a polishing pad fixed to the platen of a polishing machine. Double-sided adhesive tape is usually used to fix the polishing cloth or polishing pad to the platen of the polishing machine. This double-sided adhesive tape for fixing the polishing cloth is required to have sufficient adhesive strength to prevent the polishing cloth from peeling off during polishing, and to be able to be re-detached from the platen without leaving any adhesive residue when replacing the used polishing cloth.

[0003] As an example of a double-sided adhesive tape for fixing an abrasive cloth, Patent Documents 1 and 2 describe a double-sided adhesive tape for fixing an abrasive material, which has a specific heat-activated adhesive on one side of a plastic film support and a removable adhesive layer on the other side of the plastic film support, with the heat-activated adhesive layer being the bonding surface with the abrasive material.

[0004] JP-A-6-145611 JP-A-6-172721

[0005] In recent years, the semiconductor field has seen remarkable technological innovation in miniaturization, from the 5-nanometer generation to the 3-nanometer generation and then to the 2-nanometer generation, and semiconductors are becoming increasingly sophisticated (for example, increasing memory capacity and speeding up information communication).The polishing process for such semiconductors requires high polishing precision because polishing is performed in a much smaller area than before.

[0006] To achieve high polishing accuracy, specifically, the flatness of the polishing pad fixed to the polishing apparatus during polishing is required. There are two indicators of flatness: global flatness, which measures the entire polishing pad, and edge flatness, which measures the edge of the polishing pad. Edge flatness is important for achieving polishing accuracy with miniaturization. However, edge flatness is difficult to adjust using conventional equipment such as polishing apparatuses, and polishing accuracy can deteriorate with miniaturization. Furthermore, reduced polishing accuracy can reduce the number of semiconductors (e.g., chips) that can be extracted through the polishing process, resulting in a lower yield of the polishing process.

[0007] An object of the present invention is to provide a laminate that can improve polishing accuracy and yield in a polishing process, a method for fixing a polishing pad using the laminate, and a foam and a laminate sheet that can be used with the laminate.

[0008] Disclosure 1 provides a laminate used in a polishing process for bonding and fixing a polishing pad to a platen of a polishing machine, the laminate comprising a foam, a first pressure-sensitive adhesive layer attached to one side of the foam to be bonded to the polishing pad, and a second pressure-sensitive adhesive layer attached to the other side of the foam to be bonded to the platen of the polishing machine, the foam having a 25% compressive strength of 0.18 MPa or more and 3.5 MPa or less, and a Shore A hardness of 45 or more and 100 or less, and satisfying the following first or second configuration: First configuration: The foam contains a polyolefin-based foam, and the density of the foam is 185 kg / m ３ More than 500kg / m ３ The second configuration: the foam comprises at least one selected from the group consisting of a polyurethane foam, a rubber foam, and an acrylic foam. Disclosure 2 is the laminate of Disclosure 1, wherein in the first configuration, the polyolefin foam comprises at least one selected from the group consisting of a polyethylene foam and a polypropylene foam. Disclosure 3 is the laminate of Disclosure 2, wherein in the second configuration, the density of the foam is 350 kg / m ３ More than 700kg / m ３The laminate of Disclosure 1 or 2, wherein the foam satisfies 0.18≦X≦3.5 and 1.7ln(X)+48≦Y≦10ln(X)+87 in an XY plane with the 25% compressive strength (MPa) as the X coordinate and the Shore A hardness as the Y coordinate. Disclosure 5 is the laminate of Disclosure 1, 2, 3, or 4, wherein the foam has a thickness of 500 μm or more and 2000 μm or less. Disclosure 6 is the laminate of Disclosure 1, 2, 3, 4, or 5, wherein the first pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23° C. of 20 N / 25 mm or more. Disclosure 7 is the laminate of Disclosure 1, 2, 3, 4, 5, or 6, wherein the first pressure-sensitive adhesive layer has a thickness of 30 μm or more and 150 μm or less. Disclosure 8 is the laminate of Disclosures 1, 2, 3, 4, 5, 6, or 7, wherein the second pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of 5.0 N / 25 mm or more. Disclosure 9 is the laminate of Disclosures 1, 2, 3, 4, 5, 6, 7, or 8, wherein the second pressure-sensitive adhesive layer has a thickness of 20 μm or more and 150 μm or less. Disclosure 10 is the laminate of Disclosures 1, 2, 3, 4, 5, 6, 7, 8, or 9, wherein the laminate has a first intermediate layer between the foam and the first pressure-sensitive adhesive layer. Disclosure 11 is the laminate of Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein the laminate has a third pressure-sensitive adhesive layer between the foam and the first pressure-sensitive adhesive layer, and a third intermediate layer between the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer. Disclosure 12 is the laminate of Disclosure 10, wherein the laminate has a third pressure-sensitive adhesive layer between the first intermediate layer and the first pressure-sensitive adhesive layer, and a third intermediate layer between the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer. Disclosure 13 is the laminate of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, wherein the laminate has a second intermediate layer between the foam and the second pressure-sensitive adhesive layer. Disclosure 14 is the laminate of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the laminate has a fourth pressure-sensitive adhesive layer between the foam and the second pressure-sensitive adhesive layer, and a fourth intermediate layer between the second pressure-sensitive adhesive layer and the fourth pressure-sensitive adhesive layer.

[0023] Disclosure 15 is the laminate of Disclosure 13, wherein the laminate has a fourth pressure-sensitive adhesive layer between the second intermediate layer and the second pressure-sensitive adhesive layer, and a fourth intermediate layer between the second pressure-sensitive adhesive layer and the fourth pressure-sensitive adhesive layer. Disclosure 16 is the laminate of Disclosure 13, 14, or 15, wherein the total thickness of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is 20 μm or more. Disclosure 17 is the laminate of Disclosure 13, 14, 15, or 16, wherein the ratio of the thickness of the foam to the thickness from the foam to the second pressure-sensitive adhesive layer is 70% or more and 95% or less. Disclosure 18 is the laminate of Disclosure 13, 14, 15, 16, or 17, wherein the tensile modulus of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is 1500 MPa or more.

[0023] Disclosure 19 is the laminate of Disclosures 13, 14, 15, 16, 17, or 18, wherein the intermediate layer between the foam and the second pressure-sensitive adhesive layer comprises at least one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a nonwoven fabric. Disclosure 20 is the laminate of Disclosures 10 or 12, wherein the T-peel strength when the first intermediate layer is peeled from the foam is 5.0 N / 25 mm or more. Disclosure 21 is the laminate of Disclosures 13 or 15, wherein the T-peel strength when the second intermediate layer is peeled from the foam is 5.0 N / 25 mm or more. Disclosure 22 is the laminate of Disclosures 11 or 12, wherein the T-peel strength when the third intermediate layer is peeled from the third pressure-sensitive adhesive layer is 5.0 N / 25 mm or more. Disclosure 23 is the laminate of Disclosure 14 or 15, wherein the T-peel strength when the fourth intermediate layer is peeled from the fourth pressure-sensitive adhesive layer is 5.0 N / 25 mm or more. Disclosure 24 is the laminate of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23, wherein the thickness of the entire laminate is 550 μm or more and 5000 μm or less. Disclosure 25 is a method for fixing a polishing pad, comprising the step of bonding a polishing pad to a platen of a polishing machine using the laminate of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24.The present disclosure 26 relates to a foam having a 25% compressive strength of 0.18 MPa or more and 3.5 MPa or less, a Shore A hardness of 45 or more and 100 or less, and satisfying the following first or second configuration: First configuration: The foam contains a polyolefin-based foam, and the density of the foam is 185 kg / m. ３ More than 500kg / m ３ Second configuration: the foam comprises at least one selected from the group consisting of polyurethane foam, rubber foam, and acrylic foam. Disclosure 27 is the foam of Disclosure 26, wherein in the first configuration, the polyolefin foam comprises at least one selected from the group consisting of polyethylene foam and polypropylene foam. Disclosure 28 is the foam of Disclosure 26, wherein in the second configuration, the density of the foam is 350 kg / m ３ More than 700kg / m ３ Disclosure 29 is the foam of Disclosure 26, 27, or 28, having a thickness of 500 μm or more and 2000 μm or less. Disclosure 30 is the foam of Disclosure 26, 27, 28, or 29, having a compression amount of 0.1 mm or more and 1.2 mm or less when compressed at 10 N. Disclosure 31 is the foam of Disclosure 26, 27, 28, 29, or 30, having a compression amount of 0.8 mm or more and 4.0 mm or less when compressed at 200 N. Disclosure 32 is the foam of Disclosure 26, 27, 28, 29, 30, or 31, used in a laminate for bonding and fixing a polishing pad and a polishing machine platen together in a polishing process. Disclosure 33 is a laminate sheet including the foam of Disclosure 26, 27, 28, 29, 30, 31, or 32. Disclosure 34 is the laminate sheet of Disclosure 33, which has a foam containing a polyurethane foam and a PET sheet laminated on the polyurethane foam. The present invention will be described in detail below.

[0009] The present inventors have investigated a laminate having a foam and pressure-sensitive adhesive layers on both sides of the foam, with the foam satisfying a specific configuration, and have adjusted the 25% compressive strength and Shore A hardness of the foam to an appropriate range. As a result, they have found that a laminate can be obtained that can improve polishing accuracy and yield in the polishing process when used to bond and fix a polishing pad to a polishing machine surface plate in the polishing process, and have completed the present invention. The laminate of the present disclosure can improve polishing accuracy and yield in the polishing process even when the polishing target is a fine object (such as a 2-nanometer generation semiconductor), which has been difficult to achieve in the past.

[0010] The laminate of the present disclosure is used in a polishing process to bond and fix a polishing pad to a polishing machine platen. The laminate of the present disclosure has a foam, a first pressure-sensitive adhesive layer on one side of the foam, and a second pressure-sensitive adhesive layer on the other side of the foam. The laminate of the present disclosure is used by bonding the first pressure-sensitive adhesive layer to the polishing pad and the second pressure-sensitive adhesive layer to the polishing machine platen.

[0011] In the laminate of the present disclosure, the foam has a 25% compressive strength of 0.18 MPa (lower limit) and 3.5 MPa (upper limit). When the 25% compressive strength of the foam is 0.18 MPa or more, the foam does not become too flexible and excessive elastic deformation can be suppressed. This improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the laminate of the present disclosure to improve the polishing accuracy in the polishing process. In other words, the 25% compressive strength of the foam represents the hardness of the surface and is an important factor in improving in-plane flatness. When the 25% compressive strength of the foam is 3.5 MPa or less, the foam has appropriate flexibility, which improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the laminate of the present disclosure to improve the polishing accuracy in the polishing process. The 25% compressive strength of the foam is preferably 0.5 MPa (lower limit) and 3.0 MPa (upper limit), more preferably 1.0 MPa (lower limit) and 2.5 MPa (upper limit), still more preferably 1.5 MPa (lower limit) and 2.0 MPa (upper limit). In this specification, the 25% compressive strength of the foam can be measured in accordance with JIS K 6254. Specifically, the foam is cut into a 30 mm × 30 mm square shape to prepare a test piece, and the test piece is compressed in the thickness direction at a compression rate of 1 mm / min until the thickness becomes 25% of the thickness of the test piece before compression. The stress measured when the test piece is compressed in the thickness direction at a compression rate of 1 mm / min until the thickness becomes 25% of the thickness of the test piece before compression can be measured as the 25% compressive strength (MPa) of the foam.

[0012] In the laminate of the present disclosure, examples of methods for adjusting the 25% compression strength of the foam include methods that adjust the strength from the perspective of raw materials such as the type of foam and raw material ratio, the structure, thickness, and density of the foam, and the manufacturing method of the foam. Specifically, from the perspective of the raw materials of the foam, it is conceivable to adjust the 25% compression strength of the foam by adjusting the bulkiness by including an aromatic ring, adjusting the molecular weight, adjusting the glass transition temperature, adjusting the number of functional groups contributing to crosslinking, adjusting the degree of crosslinking, etc. The 25% compression strength can be adjusted higher with increasing bulk, increasing the molecular weight, increasing the glass transition temperature, increasing the number of functional groups, and increasing the degree of crosslinking, respectively. From the perspective of the structure, thickness, and density of the foam, it is conceivable to adjust the 25% compression strength of the foam by adjusting the cell size of the foam layer, adjusting the cell shape, adjusting the degree of open cell, and adjusting the presence or absence and thickness of a skin layer, etc. The 25% compression strength can be adjusted higher with decreasing cell size and increasing skin layer thickness, respectively. From the viewpoint of the manufacturing method of the foam, for example, in the case of polyurethane-based foam, manufacturing methods such as mechanical froth method and chemical foaming method affect the skin layer formed, the cell diameter, the cell shape, etc., so it is considered that the 25% compressive strength of the foam can be adjusted depending on the manufacturing method adopted.

[0013] In the laminate of the present disclosure, the foam has a Shore A hardness of 45 or less and 100 or less. When the Shore A hardness of the foam in the laminate of the present disclosure is 45 or more, the foam does not become too flexible and excessive elastic deformation can be suppressed. This improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the laminate of the present disclosure to improve the polishing accuracy in the polishing process. That is, the Shore A hardness of the foam represents the hardness at a point and is an important factor in improving edge flatness, in particular. Increasing the Shore A hardness of the foam can suppress local load deformation on the edge portion, thereby improving edge flatness. When the Shore A hardness of the foam is 100 or less, the foam has appropriate flexibility, improving the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the laminate of the present disclosure to improve the polishing accuracy in the polishing process. The Shore A hardness of the foam is preferably 50 at its lower limit and 90 at its upper limit, more preferably 60 at its lower limit and 80 at its upper limit, still more preferably 65 at its lower limit and 75 at its upper limit. In this specification, the Shore A hardness of the foam can be measured using a durometer in accordance with JIS K 6253.

[0014] In the laminate of the present disclosure, examples of methods for adjusting the Shore A hardness of the foam include methods that adjust the Shore A hardness from the perspective of raw materials such as the type of foam and raw material ratio, the structure, thickness, and density of the foam, and the manufacturing method of the foam. Specifically, from the perspective of the raw materials of the foam, it is possible to adjust the Shore A hardness of the foam by adjusting the bulkiness by including an aromatic ring, adjusting the molecular weight, adjusting the glass transition temperature, adjusting the number of functional groups contributing to crosslinking, adjusting the degree of crosslinking, etc. In these cases, the Shore A hardness can be adjusted higher as the foam becomes bulkier, the molecular weight becomes larger, the glass transition temperature becomes higher, the number of functional groups becomes larger, and the degree of crosslinking becomes higher. In terms of the structure, thickness, and density of the foam, it is possible to adjust the Shore A hardness of the foam by adjusting the cell size of the foam layer, adjusting the shape of the cells, adjusting the degree of open cell, and adjusting the presence or absence and thickness of a skin layer, etc. In these cases, it is possible to adjust the Shore A hardness of the foam by adjusting the cell size of the foam layer, adjusting the shape of the cells, adjusting the degree of open cell, adjusting the presence or absence of a skin layer and adjusting its thickness, etc. In these cases, the Shore A hardness can be adjusted higher as the cell diameter becomes smaller and the skin layer becomes thicker, respectively. In particular, it is preferable to reduce the cell diameter in order to increase the Shore A hardness of the foam. From the viewpoint of the manufacturing method of the foam, for example, in the case of polyurethane foam, manufacturing methods such as mechanical froth method and chemical foaming method affect the skin layer formed, cell diameter, cell shape, etc., so it is considered that the Shore A hardness of the foam can be adjusted depending on the manufacturing method employed. Furthermore, polyolefin foam may be stretched. Stretching makes it easier to adjust the Shore A hardness of the foam to a high value.

[0015] In the laminate of the present disclosure, the foam preferably satisfies 0.18≦X≦3.5 and 1.7ln(X)+48≦Y≦10ln(X)+87 in an XY plane with the 25% compressive strength (MPa) as the X coordinate and the Shore A hardness as the Y coordinate. When the foam satisfies 0.18≦X≦3.5 and 1.7ln(X)+48≦Y≦10ln(X)+87, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing step, and the resulting laminate can further improve the polishing accuracy in the polishing step.

[0016] In the laminate of the present disclosure, the foam may have a closed-cell structure or an open-cell structure, and preferably has an open-cell structure from the viewpoint of achieving better adhesion to the pressure-sensitive adhesive layer and the intermediate layer, which will be described later.

[0017] In the laminate of the present disclosure, the foam has a preferred thickness lower limit of 500 μm and a preferred upper limit of 2000 μm. When the foam has a thickness of 500 μm or more, excessive elastic deformation of the foam can be suppressed, improving the flatness of the polishing pad and the polished object during the polishing process, thereby enabling the resulting laminate to further improve the polishing accuracy in the polishing process. When the foam has a thickness of 2000 μm or less, the foam has appropriate flexibility, improving the edge flatness of the polishing pad and the polished object during polishing, even in the polishing process of fine polished objects, thereby enabling the resulting laminate to further improve the polishing accuracy in the polishing process. The foam's thickness is more preferably 600 μm lower, more preferably 1800 μm upper, even more preferably 700 μm lower, even more preferably 1600 μm upper, even more preferably 750 μm lower, and even more preferably 1500 μm upper. The thickness of the foam can be measured by the following method. That is, the thickness (μm) of the foam is measured at 10 points on the foam using a displacement meter (such as a "Digital Linear Gauge" manufactured by Ono Sokki Co., Ltd., measuring terminal 10 mmφ) with a measuring load of 80 g, and the arithmetic mean value of the thicknesses at 10 points is defined as the thickness of the foam.

[0018] In the laminate of the present disclosure, the foam preferably has a thickness tolerance of ±0.1 mm or less. When the thickness tolerance of the foam is within the above range, in the polishing process using the resulting laminate, the flatness of the polishing pad or the workpiece during polishing can be more easily adjusted by adjusting the pressure of equipment such as a polishing apparatus. The thickness tolerance of the foam is more preferably ±0.085 mm or less, even more preferably ±0.06 mm or less, and even more preferably ±0.05 mm or less. The thickness tolerance of the foam can be obtained by calculating the difference between the largest and smallest thicknesses of the 10 thicknesses measured on the foam in the thickness measurement described above.

[0019] In the laminate of the present disclosure, the compression amount of the foam when compressed at 10 N is preferably 0.1 mm at the lower limit and 1.2 mm at the upper limit. By setting the compression amount of the foam when compressed at 10 N to 0.1 mm or more, the foam does not become too flexible and does not deform too much under the pressure of the polishing machine. As a result, the flatness of the polishing pad and the polished object during polishing is improved in the polishing process, and the resulting laminate can further improve the polishing accuracy in the polishing process. By setting the compression amount of the foam when compressed at 10 N to 1.2 mm or less, the foam has appropriate flexibility and improves the accuracy of pressure control in the polishing machine. As a result, the flatness of the polishing pad and the polished object during polishing is improved in the polishing process, and the resulting laminate can further improve the polishing accuracy in the polishing process. The compression amount of the foam when compressed at 10 N is more preferably 0.2 mm at the lower limit and 1.0 mm at the upper limit, and even more preferably 0.4 mm at the lower limit and 0.8 mm at the upper limit.

[0020] In the laminate of the present disclosure, the compression amount of the foam when compressed at 200 N is preferably 0.8 mm at its lower limit and 4.0 mm at its upper limit. By setting the compression amount of the foam when compressed at 200 N to 0.8 mm or more, the foam does not become too flexible and does not deform too much in response to the pressure of the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the resulting laminate can further improve the polishing accuracy in the polishing process. By setting the compression amount of the foam when compressed at 200 N to 4.0 mm or less, the foam has appropriate flexibility and improves the accuracy of pressure control in the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the resulting laminate can further improve the polishing accuracy in the polishing process. The compression amount of the foam when compressed at 200 N is more preferably 1.0 mm at its lower limit and 3.5 mm at its upper limit, and even more preferably 1.5 mm at its lower limit and 3.0 mm at its upper limit.

[0021] The compression amounts of the foam when compressed at 10 N and 200 N can be measured by the following method: In accordance with JIS K 6254, a foam is cut into a 30 mm × 30 mm square shape to prepare a test piece, and the prepared test piece is compressed at a compression rate of 1 mm / min, and the displacement in the thickness direction of the foam when the compressive stress is 10 N and 200 N can be measured as the respective compression amounts (mm).

[0022] The laminate of the present disclosure may use only one type of foam as the foam, or may use a laminate of two or more types of foam.

[0023] The laminate of the present disclosure satisfies the following first or second configuration: First configuration: The foam contains a polyolefin-based foam, and the density of the foam is 185 kg / m ３ More than 500kg / m ３ The second configuration: the foam includes at least one selected from the group consisting of a polyurethane foam, a rubber foam, and an acrylic foam.

[0024] In the laminate of the present disclosure (hereinafter also referred to as the "laminate of present invention 1") that satisfies the first configuration, the foam contains a polyolefin foam. By containing a polyolefin foam, the foam can be appropriately deformed in response to stress applied during polishing, and the laminate of present invention 1 can improve the polishing accuracy in the polishing step. In this specification, the "polyolefin foam" refers to a foam composed of a polyolefin resin.

[0025] Examples of the polyolefin resin constituting the polyolefin foam in the laminate of the first invention include polyethylene resins, polypropylene resins, and polybutadiene resins. Among these, from the viewpoint of enabling the foam to deform appropriately in response to stress applied during polishing, it is preferable that the polyolefin foam include one selected from the group consisting of polyethylene foams composed of polyethylene resins and polypropylene foams composed of polypropylene resins. Examples of the polyethylene foam include foams composed of low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α-olefin copolymers, and mixtures thereof. Examples of the polypropylene foam in the laminate of the first invention include foams composed of propylene homopolymers and copolymers of propylene and other olefins.

[0026] The resin constituting the polyolefin foam in the laminate of the present invention 1 may contain components other than the polyolefin resin, such as ethylene-vinyl acetate copolymer (EVA resin), within the range that does not impair the effects of the present invention.

[0027] The method for producing the polyolefin foam in the laminate of the first invention is not particularly limited, and examples thereof include a method in which a resin composition obtained by melt-kneading a polyolefin resin, a foaming agent, etc. is molded by press molding or extrusion molding. Specifically, a polyolefin resin, a foaming agent, and, if necessary, other additives are blended and kneaded to obtain a resin composition, which is then molded into a sheet to produce a foamable resin sheet. Next, the crosslinking reaction of the obtained foamable resin sheet is allowed to proceed, and the sheet is then foamed, thereby producing the polyolefin foam.

[0028] The foamable resin sheet can be obtained, for example, by kneading various components using a kneader such as a Banbury mixer or a pressure kneader to obtain a resin composition, and then continuously extruding the resulting composition using an extruder, a calender, conveyor belt casting, or the like.

[0029] Methods for promoting the crosslinking reaction of the foamable resin sheet include crosslinking by ionizing radiation and crosslinking by organic peroxides, with crosslinking by ionizing radiation being preferred. Crosslinking by ionizing radiation can produce foams with small and uniform cell diameters. Examples of ionizing radiation include ultraviolet light, gamma rays, and electron beams. The dose of ionizing radiation is preferably 0.5 to 10 Mrad, and more preferably 1.0 to 8.0 Mrad.

[0030] As a method for foaming the foamable resin sheet, a heating method is preferably used, and examples thereof include a batch method such as an oven method, a continuous foaming method in which the foamable resin sheet is formed into a long sheet and continuously passed through a heating furnace, etc. The heating temperature when foaming the foamable resin sheet by heating is preferably 200 to 320°C, more preferably 220 to 300°C.

[0031] The foamable resin sheet may be stretched in at least one of MD (Machine Direction) and TD (Transverse Direction), preferably in both directions, during foaming. Stretching in MD and TD can improve the tensile strength of the foamable resin sheet. The foamable resin sheet may be stretched in at least one of MD and TD, preferably in both directions, during or after foaming. When the foamable resin sheet is stretched after foaming, it may be continuously stretched while maintaining the molten state at the time of foaming without being cooled after foaming, or it may be cooled and then heated again to a molten or softened state before being stretched.

[0032] In the laminate of the first invention, the density of the foam has a lower limit of 185 kg / m ３ and the upper limit is 500 kg / m ３ In the laminate of invention 1, the density of the foam is 185 kg / m ３ By satisfying the above conditions, the foam does not become too flexible and excessive elastic deformation can be suppressed, and in the polishing step, the flatness of the polishing pad and the object to be polished during polishing is improved, so that the obtained laminate can improve the polishing accuracy in the polishing step. ３ In the laminate of the first aspect of the present invention, the preferred lower limit of the density of the foam is 200 kg / m or less, so that the rigidity of the foam does not become too high and damage to the object to be polished can be suppressed. ３ , the preferred upper limit is 480 kg / m ３ and a more preferable lower limit is 250 kg / m ３ , and a more preferable upper limit is 460 kg / m ３ and a more preferable lower limit is 300 kg / m ３ , and a more preferable upper limit is 430 kg / m ３ is.

[0033] The density of the foam can be measured by cutting the foam into a test piece measuring 10 cm x 10 cm and measuring the test piece using an electronic hydrometer (manufactured by Mirage, "ED120T") in accordance with JIS K 6767.

[0034] Examples of a method for adjusting the density of the foam in the laminate of invention 1 include a method for adjusting the expansion ratio of the foam. When adjusting the expansion ratio of the foam, lowering the expansion ratio of the foam tends to increase the density of the foam.

[0035] The foam in the laminate of the first invention preferably has a flattened cell structure. By collapsing the cell structure in the foam in the thickness direction to increase the flattening ratio, when the cell structure is collapsed by pressure applied in the thickness direction during polishing, stress is more likely to escape in a direction perpendicular to the thickness direction, thereby imparting flexibility to the foam. The lower limit of the flattening ratio of the cells in the foam in the laminate of the first invention is preferably 0.2, more preferably 0.4, and even more preferably 0.8. In addition, in the laminate of the first invention, there is no particular preferred upper limit of the flattening ratio of the cells in the foam, but the practical upper limit is 10. The flattening ratio of the cells in the foam can be calculated using an X-ray CT scanner and image analysis software according to the following formula: Flattening ratio = [{(x + y) / 2} - z] / z (x = major axis, y = median axis, z = minor axis, x ≥ y ≥ z)

[0036] More specifically, the analysis using the X-ray CT scanner and the image analysis software is performed, for example, as follows. First, the center of a measurement sample obtained by cutting the foam is imaged using an X-ray CT scanner (e.g., Yamato Scientific's "TDM1000H-II (2K)" with a resolution of approximately 1.5 μm / pixel), resulting in a rectangular 3D image of 1.5 mm in length, 1.2 mm in width, and 0.3 mm in height. The resulting image is then subjected to noise removal and binarization using image analysis software (e.g., FEI's "Avizo 9.2.0") to determine the oblateness and other parameters that represent the foam's cell structure. Mo is used as the X-ray source, and imaging is performed using a lens (L0270) under the conditions of binning 2, an exposure time of 10 seconds, and 1,200 images. During image analysis, noise is first removed using the Median Filter function (Neighborhood value 26). Then, binarization is performed using the Interactive Thresholding function. The threshold is set to 90 out of 256 gradations. In the binarized image, whether a bubble is an isolated bubble or an open bubble is determined by whether or not there is a break in the continuous pixel portion. Furthermore, to calculate the major, median, and minor diameters, the bubbles are first divided at their tangent points to determine the center of gravity of the bubble. Next, a rectangular parallelepiped is set with its center of gravity at the same position as the center of gravity and inscribed within the bubble, and the lengths of the three orthogonal sides are determined as the major, median, and minor diameters, respectively, in descending order of length. Note that bubbles with a major diameter of less than 10 μm are excluded.

[0037] The method for adjusting the cell flatness of the polyolefin foam in the laminate of the first invention to fall within the above range is not particularly limited, but examples thereof include a method in which the polyolefin foam is stretched during foaming in the production thereof.

[0038] In a laminate of the present disclosure that satisfies the second configuration (hereinafter also referred to as "laminate of present invention 2"), the foam comprises at least one selected from the group consisting of polyurethane foam, rubber foam, and acrylic foam. By including at least one selected from the group consisting of polyurethane foam, rubber foam, and acrylic foam, the foam can deform appropriately in response to stress applied during polishing, and the laminate of present invention 2 can improve polishing accuracy in the polishing step.

[0039] The polyurethane foam in the laminate of the second aspect of the present invention is not particularly limited as long as it is a foam composed of a polyurethane resin. Examples of the polyurethane resin include those obtained by reacting a polyol compound with a polyisocyanate compound. Examples of the polyol compound include polyester polyols and polyether polyols. Examples of the polyester polyol include condensation polyester polyols, lactone polyester polyols, and polycarbonate polyols obtained by reacting a polycarboxylic acid such as adipic acid or phthalic acid with a polyol such as ethylene glycol, diethylene glycol, propylene glycol, or glycerin. Examples of the polyether polyol include compounds obtained by adding an alkylene oxide to polypropylene glycol, polytetramethylene glycol, or glycerin. Examples of the polyisocyanate compound include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, and isophorone diisocyanate (IPDI).

[0040] The resin constituting the polyurethane foam may contain components other than the urethane resin, such as titanium oxide and carbon black, within the scope of the present invention.

[0041] Examples of methods for producing the polyurethane foam in the laminate of invention 2 include a method of reacting a foam composition containing the polyol compound, the polyisocyanate compound, and, if necessary, a blowing agent and a catalyst, followed by foaming and curing. Alternatively, a laminate sheet can be produced by reacting the foam composition on a film such as a PET film and laminating a PET film on one side of the foam composition.

[0042] Examples of the foaming agent include water, low-boiling compounds such as methylene chloride, carbon dioxide gas, etc. Examples of the catalyst include tertiary amines such as N,N',N'-trimethylaminoethylpiperazine, triethylenediamine, dimethylethanolamine, N-ethylmorpholine, etc., organometallic compounds such as tin octoate, acetates, alkali metal alcoholates, etc.

[0043] The rubber foam in the laminate of present invention 2 is not particularly limited as long as it is a foam made of a rubber resin, and examples thereof include foam made of natural rubber, foam made of chloroprene rubber, foam made of ethylene propylene rubber, and foam made of synthetic rubber.

[0044] The resin constituting the rubber foam in the laminate of the second invention may contain components other than the rubber resin as long as the effects of the invention are not impaired.

[0045] The acrylic foam in the laminate of the second invention is not particularly limited as long as it is a foam made of an acrylic resin, and examples thereof include FORMAC (manufactured by Sekisui Plastics Co., Ltd.).

[0046] The resin constituting the acrylic foam in the laminate of invention 2 may contain components other than the acrylic resin, such as a styrene resin or an olefin resin, within the range that does not impair the effects of the invention.

[0047] In the laminate of the second invention, the density of the foam has a preferable lower limit of 350 kg / m ３ , the preferred upper limit is 700 kg / m ３ In the laminate of invention 2, the density of the foam is 350 kg / m ３ By satisfying the above conditions, the foam does not become too flexible, and excessive elastic deformation can be further suppressed, and in the polishing step, the flatness of the polishing pad and the object to be polished during polishing is further improved, so that the obtained laminate can further improve the polishing accuracy in the polishing step. ３ In the laminate of the second aspect of the present invention, the lower limit of the density of the foam is more preferably 400 kg / m or less, so that the rigidity of the foam does not become too high and damage to the object to be polished can be further suppressed. ３ , and a more preferable upper limit is 600 kg / m ３ and a more preferable lower limit is 450 kg / m ３ , and a more preferable upper limit is 580 kg / m ３ and an even more preferable lower limit is 475 kg / m ３ , and an even more preferable upper limit is 560 kg / m ３ is.

[0048] In the laminate of the second invention, examples of methods for adjusting the density of the foam include changing the foaming method used in producing the foam and adjusting the content of the polyisocyanate compound in the foam composition. When changing the foaming method used in producing the foam, the density of the foam is more likely to be increased when a mechanical froth method is used as the foaming method than when a chemical foaming method is used. When adjusting the content of the polyisocyanate compound in the foam composition, increasing the content of the polyisocyanate compound tends to increase the density of the foam.

[0049] As described above, the laminate of the present disclosure has a first pressure-sensitive adhesive layer attached to one side of the foam to be bonded to a polishing pad, and a second pressure-sensitive adhesive layer attached to the other side of the foam to be bonded to a polishing machine platen. Hereinafter, matters common to the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer will be described without specifying the specific pressure-sensitive adhesive layer or simply as the "pressure-sensitive adhesive layer." The pressure-sensitive adhesive layer is not particularly limited and may be a pressure-sensitive adhesive layer or a heat-sensitive adhesive layer.

[0050] The pressure-sensitive adhesive layer preferably contains a base resin. Examples of the base resin include (meth)acrylic copolymers and rubber-based resins. In this specification, "(meth)acrylic" means acrylic or methacrylic.

[0051] Specific examples of the (meth)acrylic copolymer include copolymers of (meth)acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms. Examples of the (meth)acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, and n-decyl (meth)acrylate. These (meth)acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms may be used alone, or two or more types may be used in combination.

[0052] The copolymer of the alkyl (meth)acrylate ester having an alkyl group having 1 to 12 carbon atoms may further contain another copolymerization component copolymerizable with the alkyl (meth)acrylate ester having an alkyl group having 1 to 12 carbon atoms. Examples of the other copolymerization component include 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, allyl glycidyl ether, crotonic acid, maleic acid, itaconic acid, n-methylolacrylamide, maleic anhydride, vinyl acetate, and styrene. These other copolymerization components may be used alone or in combination of two or more.

[0053] The weight-average molecular weight (Mw) of the (meth)acrylic copolymer preferably has a lower limit of 300,000 and an upper limit of 1,200,000. When the weight-average molecular weight (Mw) of the (meth)acrylic copolymer is 300,000 or more, the bulk cohesive strength of the pressure-sensitive adhesive layer is improved, and the adhesive strength and retention performance of the pressure-sensitive adhesive layer are further improved. When the weight-average molecular weight (Mw) of the (meth)acrylic copolymer is 1,200,000 or less, the pressure-sensitive adhesive layer does not become too hard, and the adhesive strength is further improved. The weight-average molecular weight (Mw) of the (meth)acrylic copolymer more preferably has a lower limit of 350,000 and an upper limit of 1,100,000, and an even more preferably has a lower limit of 400,000 and an even more preferably has an upper limit of 1,000,000. In this specification, the weight-average molecular weight (Mw) refers to the weight-average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene. Specifically, for example, the measurement can be performed using a Waters "2690 Separations Module" as the measuring instrument, a Showa Denko "GPC KF-806L" as the column, THF as the solvent, under conditions of a sample flow rate of 1 mL / min and a column temperature of 40° C. As the detector, for example, a differential refractometer or the like can be used.

[0054] The weight average molecular weight (Mw) of the (meth)acrylic copolymer can be adjusted to fall within the above range by, for example, adjusting the composition, polymerization method, polymerization conditions, etc. of the (meth)acrylic copolymer.

[0055] The polymerization method for synthesizing the (meth)acrylic copolymer can be a conventionally known method of radically reacting the above-mentioned (meth)acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms and other copolymerization components in the presence of a polymerization initiator, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc. Among these, solution polymerization is preferred because of its ease of synthesis.

[0056] When solution polymerization is used as the polymerization method, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether, etc. These reaction solvents may be used alone or in combination of two or more.

[0057] Examples of the polymerization initiator include organic peroxides and azo compounds. Examples of the organic peroxides include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. Examples of the azo compounds include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

[0058] Examples of the rubber-based resin include a block copolymer (A) of a monovinyl-substituted aromatic compound block and a conjugated diene compound block (hereinafter simply referred to as "block copolymer (A)"), in which the monovinyl-substituted aromatic compound block is a hard segment portion and the conjugated diene compound block is a soft segment portion. Examples of the monovinyl-substituted aromatic compounds include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene. Examples of the tertiary amino group-containing diphenylethylene include 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene. Among these, styrene is preferred because of its industrial availability. These monovinyl-substituted aromatic compounds may be used alone or in combination of two or more. Examples of the conjugated diene compounds include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. Of these, isoprene and butadiene are preferred, and isoprene is more preferred, from the viewpoint of the balance between slurry properties and adhesion to rough surfaces. These conjugated diene compounds may be used alone or in combination of two or more.

[0059] Examples of the block copolymer (A) include styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-butadiene-butylene-styrene (SBBS) block copolymer, styrene-ethylene-butylene-styrene (SEBS) block copolymer, styrene-ethylene-propylene-styrene (SEPS) block copolymer, and hydrogenated styrene-butylene rubber (HSBR). Among these, a styrene-isoprene-styrene (SIS) block copolymer is preferred because it has sufficient flexibility to exhibit adhesion to rough surfaces. Furthermore, the block copolymer (A) preferably contains a hydrogenated product because this further improves the shear strength of the first pressure-sensitive adhesive layer at high temperatures. These block copolymers may be used alone, or two or more types may be used in combination.

[0060] The block copolymer (A) preferably contains a triblock copolymer of the hard segment portion and the soft segment portion, and may contain, in addition to the triblock copolymer, a diblock copolymer of the hard segment portion and the soft segment portion.

[0061] The block copolymer (A) preferably contains a block copolymer having a styrene content of 10% by mass or more and 20% by mass or less and a diblock content of 25% by mass or more and 80% by mass or less. In this case, sufficient flexibility is exhibited, thereby further improving the adhesion of the pressure-sensitive adhesive layer to rough surfaces. Furthermore, the first pressure-sensitive adhesive layer has sufficiently high shear strength and slurry resistance at high temperatures. More preferably, the block copolymer (A) contains a block copolymer having a styrene content of 10% by mass or more and 20% by mass or less and a diblock content of 50% by mass or more and 80% by mass or less. It is particularly preferable that the block copolymer (A) contains only block copolymers having a styrene content of 10% by mass or more and 20% by mass or less and a diblock content of 50% by mass or more and 80% by mass or less.

[0062] The pressure-sensitive adhesive layer may contain a tackifier resin, which improves the adhesive strength to the polishing pad or platen.

[0063] Examples of the tackifying resin include terpene resins, petroleum resins, terpene phenol resins, rosin ester resins, coumarone resins, etc. Among these, from the viewpoint of the balance between slurry resistance and shear strength at high temperatures, it is preferable that the pressure-sensitive adhesive layer contains a terpene phenol resin.

[0064] The content of the tackifier resin is preferably 3 parts by mass or more at a lower limit and 100 parts by mass or more at an upper limit relative to 100 parts by mass of the base resin. When the content of the tackifier resin is 3 parts by mass or more, the adhesive strength of the PSA layer is further improved. When the content of the tackifier resin is 100 parts by mass or less, the PSA layer does not become too hard, and the adhesive strength and retention are further improved. The lower limit of the content of the tackifier resin is more preferably 5 parts by mass, and the upper limit is more preferably 75 parts by mass, and the even more preferably 10 parts by mass and the even more preferably 50 parts by mass.

[0065] When the pressure-sensitive adhesive layer contains a (meth)acrylic copolymer, it is preferable that the pressure-sensitive adhesive layer contains a crosslinking agent. By containing the crosslinking agent in the pressure-sensitive adhesive layer, the (meth)acrylic copolymer can form a crosslinked structure in which molecules are chemically crosslinked via the crosslinking agent, thereby further improving the cohesive strength of the pressure-sensitive adhesive layer. As a result, the retention of the pressure-sensitive adhesive layer is further improved.

[0066] Examples of the crosslinking agent include epoxy-based crosslinking agents, isocyanate-based crosslinking agents, etc. Among these, the isocyanate-based crosslinking agents are preferred from the viewpoint of the balance between cohesive strength and adhesiveness.

[0067] The content of the crosslinking agent is preferably 0.1 parts by mass at the lower limit and 5.0 parts by mass at the upper limit relative to 100 parts by mass of the base resin. When the content of the crosslinking agent is 0.1 parts by mass or more, the (meth)acrylic copolymer can appropriately form a crosslinked structure, thereby further improving the cohesive strength of the pressure-sensitive adhesive layer. As a result, the retention of the pressure-sensitive adhesive layer is further improved. When the content of the crosslinking agent is 5.0 parts by mass or less, the pressure-sensitive adhesive layer does not become too hard, and the adhesive strength and retention are further improved. The lower limit of the content of the crosslinking agent is more preferably 0.3 parts by mass, and the upper limit is more preferably 4.0 parts by mass, and the lower limit is even more preferably 0.5 parts by mass, and the upper limit is even more preferably 3.5 parts by mass.

[0068] The pressure-sensitive adhesive layer may contain conventionally known fine particles and additives, such as inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, and inorganic fillers, as needed.

[0069] The first pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 20 N / 25 mm or more. When the first pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of 20 N / 25 mm or more, the adhesive strength of the resulting laminate to a polishing pad is further improved, and peeling during the polishing process can be further suppressed. The lower limit of the 180° peel strength from SUS at 23°C of the first pressure-sensitive adhesive layer is more preferably 25 N / 25 mm, even more preferably 30 N / 25 mm, and even more preferably 35 N / 25 mm. There is no particular upper limit to the preferred 180° peel strength from SUS at 23°C of the first pressure-sensitive adhesive layer, but a substantial upper limit is 50 N / 25 mm.

[0070] The second pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 5.0 N / 25 mm (lower limit) and 35 N / 25 mm (upper limit). When the second pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of 5.0 N / 25 mm or more, the adhesive strength of the resulting laminate to the surface plate is further improved, and peeling during the polishing process can be further suppressed. When the second pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of 35 N / 25 mm or less, the resulting laminate can be easily peeled from the surface plate after the polishing process is completed. The second pressure-sensitive adhesive layer's 180° peel strength from SUS at 23°C is more preferably 7.0 N / 25 mm (lower limit), more preferably 32 N / 25 mm (upper limit), even more preferably 10 N / 25 mm (lower limit), and even more preferably 30 N / 25 mm (upper limit).

[0071] The 180° peel strength of the first pressure-sensitive adhesive layer from SUS at 23° C. and the 180° peel strength of the second pressure-sensitive adhesive layer from SUS at 23° C. can be measured in accordance with JIS Z 0237, for example, by the following method. That is, first, a pressure-sensitive adhesive solution is applied to a 23 μm-thick PET film, and then dried at 110° C. for 5 minutes to prepare a pressure-sensitive adhesive tape for 180° peel strength measurement. Next, a 2 kg rubber roller is rolled back and forth once on a SUS plate (a SUS304 plate that has been washed with ethanol and then wiped dry) at a reciprocating speed of 300 mm / min, and the obtained pressure-sensitive adhesive tape for 180° peel strength measurement is laminated to the SUS plate to prepare a measurement sample. The prepared measurement sample is subjected to a 180° peel test in accordance with JIS Z 0237 using a tensile tester ("Autograph AGS-X" manufactured by Shimadzu Corporation) at 23°C and a tensile speed of 300 mm / min, in which an adhesive tape for 180° peel force measurement is peeled from an SUS plate, and the 180° peel force (N / 25 mm) against SUS is measured.

[0072] The thickness of the first adhesive layer is preferably 30 μm at the lower limit and 150 μm at the upper limit. When the thickness of the first adhesive layer is 30 μm or more, the adhesive strength to the polishing pad is further improved, and peeling during the polishing process can be further suppressed. Furthermore, when the thickness of the first adhesive layer is 150 μm or less, shear shear during the polishing process can be further suppressed, thereby further improving the polishing accuracy during the polishing process. The thickness of the first adhesive layer is more preferably 45 μm at the lower limit and 120 μm at the upper limit, and even more preferably 55 μm at the lower limit and 110 μm at the upper limit.

[0073] The thickness of the second pressure-sensitive adhesive layer preferably has a lower limit of 20 μm and an upper limit of 150 μm. When the thickness of the second pressure-sensitive adhesive layer is 20 μm or more, the adhesive strength to the surface plate is further improved, and peeling during the polishing process can be further suppressed. Furthermore, when the thickness of the second pressure-sensitive adhesive layer is 150 μm or less, shear slip during the polishing process can be further suppressed, and the polishing accuracy during the polishing process can be further improved. The thickness of the second pressure-sensitive adhesive layer is more preferably 25 μm or less, and more preferably 120 μm or less, and even more preferably 30 μm or less, and even more preferably 110 μm or less.

[0074] The pressure-sensitive adhesive layer preferably exhibits a slippage of 1 mm or less when subjected to a retention test in which a 1 kg load is applied in the shear direction at 40°C for 1 hour after being bonded to a stainless steel plate. When the pressure-sensitive adhesive layer exhibits the above-described retention test results, shear slippage during the polishing process can be further suppressed, thereby improving the polishing accuracy during the polishing process. The retention test results preferably exhibit a slippage of 0.5 mm or less, more preferably 0.3 mm or less, even more preferably 0.2 mm or less, and most preferably 0 mm. The retention test can be performed by the following method. A schematic diagram illustrating the retention test method is shown in Figure 1. First, a 23 μm-thick PET film is coated with a pressure-sensitive adhesive solution and dried at 110°C for 3 minutes to prepare a pressure-sensitive adhesive tape 1 for the retention test. The pressure-sensitive adhesive tape 1 for the retention test is cut into 25 mm-wide strips and then bonded to a stainless steel plate 2 by moving a 2 kg rubber roller back and forth at a speed of 300 mm / min. Next, an incision is made in the adhesive tape 1 for the retention test so that the adhesive area is 25 mm x 25 mm. Thereafter, the tape is left to stand at 23°C for 20 minutes, placed in an oven at 40°C, heated for a further 15 minutes, and then, while maintaining the temperature at 40°C, a load of 1 kg is applied in the shear direction using a 1 kg weight 3 as shown in Figure 1. It is checked whether the adhesive tape has fallen off, and if it has not fallen off after 1 hour, the amount of movement (displacement) from the incision position is measured using a scale magnifying glass.

[0075] The laminate of the present disclosure may include layers other than the foam, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive layer, as long as the effects of the present invention are not impaired.

[0076] The laminate of the present disclosure preferably has a first intermediate layer between the foam and the first pressure-sensitive adhesive layer (hereinafter simply referred to as "having the first intermediate layer"). The laminate of the present disclosure also preferably has a second intermediate layer between the foam and the second pressure-sensitive adhesive layer (hereinafter simply referred to as "having the second intermediate layer"). By satisfying at least one requirement selected from the group consisting of having the first intermediate layer and having the second intermediate layer, the resulting laminate has superior flexibility and ensures rigidity, allowing the polished object to be held flatter. It is particularly preferable that the laminate of the present disclosure has the first intermediate layer and the second intermediate layer.

[0077] Hereinafter, matters common to the first intermediate layer and the second intermediate layer will be described without specifying the particular intermediate layer or simply as the "intermediate layer." The intermediate layer is not particularly limited as long as it is a non-foamed film or sheet, and examples thereof include polyolefin resin films composed of polyolefin resins such as polyethylene and polypropylene, polyester resin films composed of polyester resins such as ethylene-vinyl acetate copolymer, polyvinyl chloride, and polyethylene terephthalate, and nonwoven fabrics. In particular, from the viewpoint of further improving cushioning properties and ensuring rigidity to hold the polished object more flatly, the laminate of the present disclosure preferably includes at least one material selected from the group consisting of polyethylene terephthalate film, polypropylene film, and nonwoven fabric as the intermediate layer. Furthermore, from the viewpoint of a balance between cushioning properties and rigidity, it is more preferable that the second intermediate layer include at least one material selected from the group consisting of polyethylene terephthalate film, polypropylene film, and nonwoven fabric.

[0078] An example of the polyethylene terephthalate film is E5200 (manufactured by Toyobo Co., Ltd.). The polypropylene film is preferably a biaxially oriented polypropylene film, including those described below. An example of the biaxially oriented polypropylene film is OPP#60 (FOS-BTSK, manufactured by Futamura Chemical Co., Ltd.). An example of the nonwoven fabric is SPC base paper (manufactured by Nippon Paper Papylia Co., Ltd.).

[0079] Furthermore, the surface of the intermediate layer may be subjected to corona discharge treatment, primer treatment, etc., as necessary, and the above-mentioned treatments can further improve the adhesion between the intermediate layer and the foam, and between the intermediate layer and the pressure-sensitive adhesive layer.

[0080] The preferred lower limit of the thickness of the intermediate layer is 20 μm. When the thickness of the intermediate layer is 20 μm or more, the edge flatness of the polishing pad or the workpiece during polishing is improved in the polishing process, so that the resulting laminate can further improve the polishing accuracy in the polishing process. The preferred lower limit of the thickness of the intermediate layer is 30 μm, even more preferably 50 μm, and even more preferably 100 μm. In addition, from the viewpoint of the balance between edge flatness and handleability, the preferred upper limit of the thickness of the intermediate layer is 250 μm, more preferably 240 μm, and even more preferably 230 μm. In particular, from the viewpoint of the balance between flatness during polishing and handleability during processing, it is more preferred that the thickness of the second intermediate layer satisfies the above-mentioned range.

[0081] The second intermediate layer preferably has a lower limit of 1500 MPa in tensile modulus. When the second intermediate layer has a tensile modulus of 1500 MPa or more, the handleability of the resulting laminate when bonded to a surface plate is further improved. Furthermore, the resulting laminate can further improve the polishing accuracy in the polishing process. The lower limit of the tensile modulus of the second intermediate layer is more preferably 4000 MPa, even more preferably 5000 MPa, and even more preferably 10000 MPa. Furthermore, from the viewpoint of the balance between the flatness of the edge during polishing and the handleability when bonded to a surface plate, the upper limit of the tensile modulus of the second intermediate layer is preferably 30000 MPa, more preferably 20000 MPa, and even more preferably 15000 MPa. The tensile modulus of the second intermediate layer can be measured in accordance with JIS K 7161 by the following method, etc. That is, a test piece is prepared by punching the intermediate layer into a dumbbell shape using a punching blade ("Tensile No. 1 Dumbbell" manufactured by Kobunshi Keiki Co., Ltd.), and the prepared test piece is pulled to break using a tensile tester (for example, "Autograph AGS-X" manufactured by Shimadzu Corporation) at 23°C and a pulling rate of 100 mm / min, to measure the tensile strength. In the obtained tensile strength-strain curve, the slope of the tensile strength at strains of 1 to 3% is calculated, and this slope is taken as the tensile modulus (MPa).

[0082] Examples of methods for adjusting the tensile modulus of the intermediate layer include a method of stretching the intermediate layer when it is produced, a method of adjusting the thickness, etc. In the method of stretching the intermediate layer when it is produced, the strength of the intermediate layer is easily exhibited when it is biaxially stretched, so the tensile modulus is likely to be high, and in the method of adjusting the thickness, the tensile modulus is likely to be high when the thickness is large.

[0083] The preferred lower limit of the T-peel strength when the first intermediate layer is peeled from the foam (hereinafter simply referred to as the "T-peel strength of the first intermediate layer") is 5.0 N / 25 mm. When the T-peel strength of the first intermediate layer is 5.0 N / 25 mm or more, the resulting laminate can be more effectively prevented from peeling due to shear stress during the polishing process. The more preferred lower limit of the T-peel strength of the first intermediate layer is 10 N / 25 mm, an even more preferred lower limit is 15 N / 25 mm, and an even more preferred lower limit is 20 N / 25 mm. There is no particular preferred upper limit for the T-peel strength of the first intermediate layer, but the practical upper limit is 50 N / 25 mm. The T-peel strength of the first intermediate layer can be measured by the following method, etc. That is, first, the obtained laminate is cut into a size of 25 mm wide x 100 mm long, and a measurement sample is prepared by making a 10 mm cut with a cutter at both longitudinal ends of the interface between the foam and the first intermediate layer to separate the ends and create a gripping margin. Then, using a tensile tester (e.g., Shimadzu Corporation's "Autograph AGS-X"), both ends of the first intermediate layer in the prepared measurement sample are gripped with the chucks of the tensile tester, and the first intermediate layer is peeled away from the foam at a rate of 300 mm / min, thereby measuring the T-peel strength of the first intermediate layer.

[0084] The preferred lower limit of the T-peel strength when the second intermediate layer is peeled from the foam (hereinafter simply referred to as the "T-peel strength of the second intermediate layer") is 5.0 N / 25 mm. When the T-peel strength of the second intermediate layer is 5.0 N / 25 mm or more, the resulting laminate can be more effectively prevented from peeling due to shear stress during the polishing process. The more preferred lower limit of the T-peel strength of the second intermediate layer is 10 N / 25 mm, an even more preferred lower limit is 15 N / 25 mm, and an even more preferred lower limit is 20 N / 25 mm. There is no particular preferred upper limit for the T-peel strength of the second intermediate layer, but a practical upper limit is 50 N / 25 mm. The T-peel strength of the second intermediate layer can be measured using the same method as that for the first intermediate layer.

[0085] The laminate of the present disclosure preferably (i) has a third pressure-sensitive adhesive layer between the foam and the first pressure-sensitive adhesive layer, and a third intermediate layer between the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer, or (ii) has a third pressure-sensitive adhesive layer between the first intermediate layer and the first pressure-sensitive adhesive layer, and a third intermediate layer between the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer (hereinafter, (i) and (ii) are collectively referred to as "having the third pressure-sensitive adhesive layer and the third intermediate layer"). By having the third pressure-sensitive adhesive layer and the third intermediate layer, the laminate of the present disclosure can ensure rigidity to hold the object to be polished or the abrasive flat, and can provide a laminate that can further improve handleability when attached to an adherend.

[0086] The third pressure-sensitive adhesive layer may have the same structure as the first pressure-sensitive adhesive layer, for example.

[0087] The third pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 5.0 N / 25 mm or more, which is preferable for the lower limit. When the third pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of 5.0 N / 25 mm or more, adhesion to the rough surface of a foam is further improved. The third pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 10 N / 25 mm or more, and an even more preferable lower limit is 15 N / 25 mm. There is no particular preferable upper limit for the 180° peel strength from SUS at 23°C of the third pressure-sensitive adhesive layer, but a substantial upper limit is 50 N / 25 mm. The 180° peel strength of the third pressure-sensitive adhesive layer from SUS at 23°C can be measured in the same manner as the 180° peel strength of the first pressure-sensitive adhesive layer from SUS at 23°C and the 180° peel strength of the second pressure-sensitive adhesive layer from SUS at 23°C.

[0088] The third pressure-sensitive adhesive layer preferably has a thickness of 5 μm or less and a thickness of 150 μm or less. When the thickness of the third pressure-sensitive adhesive layer is 5 μm or more, adhesion to the rough surface of the foam is further improved. When the thickness of the third pressure-sensitive adhesive layer is 150 μm or less, shear slippage during polishing is reduced, thereby improving polishing accuracy. The thickness of the third pressure-sensitive adhesive layer is more preferably 10 μm or less and a more preferably 120 μm or less, and even more preferably 15 μm or less and a still more preferably 100 μm or less.

[0089] The third intermediate layer may have the same structure as the first intermediate layer.

[0090] The third intermediate layer has a preferred lower limit of thickness of 20 μm. When the thickness of the third intermediate layer is 20 μm or more, the edge flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, so that the resulting laminate can further improve the polishing accuracy in the polishing process. The preferred lower limit of the thickness of the third intermediate layer is 30 μm, an even more preferred lower limit is 50 μm, and an even more preferred lower limit is 100 μm. Furthermore, from the viewpoint of handleability during processing, the preferred upper limit of the thickness of the third intermediate layer is 250 μm, a more preferred upper limit is 220 μm, and an even more preferred upper limit is 190 μm.

[0091] The preferred lower limit of the T-peel strength when the third intermediate layer is peeled from the third pressure-sensitive adhesive layer (hereinafter also referred to simply as the "T-peel strength of the third intermediate layer") is 5.0 N / 25 mm. When the T-peel strength of the third intermediate layer is 5.0 N / 25 mm or more, the resulting laminate can be more effectively prevented from peeling due to shear stress during the polishing process. The lower limit of the T-peel strength of the third intermediate layer is more preferably 10 N / 25 mm, even more preferably 15 N / 25 mm, and even more preferably 20 N / 25 mm. In particular, when the laminate of the present disclosure does not have the first intermediate layer, it is more preferred that the T-peel strength of the third intermediate layer satisfy the above-mentioned range. Furthermore, there is no particular preferred upper limit for the T-peel strength of the third intermediate layer, but the practical upper limit is 50 N / 25 mm. The T-peel strength of the third intermediate layer can be measured by the following method, etc. That is, first, the obtained laminate is cut into a size of 25 mm wide x 100 mm long, and a measurement sample is prepared by making a 10 mm cut with a cutter at both longitudinal ends of the third pressure-sensitive adhesive layer that contacts the third intermediate layer for which the T-peel strength is to be measured, separating the ends and creating a gripping margin. Then, using a tensile tester (e.g., Shimadzu Corporation's "Autograph AGS-X"), both ends of the third intermediate layer in the prepared measurement sample are gripped with the chucks of the tensile tester, and the third intermediate layer is peeled from the third pressure-sensitive adhesive layer at a speed of 300 mm / min, thereby measuring the T-peel strength of the third intermediate layer.

[0092] The laminate of the present disclosure preferably (iii) has a fourth pressure-sensitive adhesive layer between the foam and the second pressure-sensitive adhesive layer and a fourth intermediate layer between the second pressure-sensitive adhesive layer and the fourth pressure-sensitive adhesive layer, or (iv) has a fourth pressure-sensitive adhesive layer between the second intermediate layer and the second pressure-sensitive adhesive layer and a fourth intermediate layer between the second pressure-sensitive adhesive layer and the fourth pressure-sensitive adhesive layer (hereinafter, (iii) and (iv) are collectively referred to as "having the fourth pressure-sensitive adhesive layer and the fourth intermediate layer"). By having the fourth pressure-sensitive adhesive layer and the fourth intermediate layer, it is possible to obtain a laminate that ensures rigidity to hold the object to be polished or the abrasive flat and that can further improve handleability when peeled off from the platen.

[0093] The fourth pressure-sensitive adhesive layer may have the same structure as the second pressure-sensitive adhesive layer, for example.

[0094] The fourth pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 5 N / 25 mm or more, which further improves adhesion to the rough surface of a foam. The fourth pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 5 N / 25 mm or more, which further improves adhesion to the rough surface of a foam. The fourth pressure-sensitive adhesive layer has a 180° peel strength from SUS at 23°C of preferably 10 N / 25 mm or more, and an even more preferable lower limit of 15 N / 25 mm. There is no particular upper limit to the 180° peel strength from SUS at 23°C of the fourth pressure-sensitive adhesive layer, but a substantial upper limit is 50 N / 25 mm. The 180° peel strength of the fourth pressure-sensitive adhesive layer from SUS at 23°C can be measured by the same method as the 180° peel strength of the first pressure-sensitive adhesive layer from SUS at 23°C, the 180° peel strength of the second pressure-sensitive adhesive layer from SUS at 23°C, and the 180° peel strength of the third pressure-sensitive adhesive layer from SUS at 23°C.

[0095] The fourth pressure-sensitive adhesive layer preferably has a thickness of 5 μm or less and a thickness of 150 μm or less. When the thickness of the fourth pressure-sensitive adhesive layer is 5 μm or more, adhesion to the rough surface of the foam is further improved. When the thickness of the fourth pressure-sensitive adhesive layer is 150 μm or less, shear slippage during polishing is reduced, and polishing accuracy is further improved. The thickness of the fourth pressure-sensitive adhesive layer is more preferably 10 μm or less and 120 μm or less, and even more preferably 15 μm or less and 100 μm or less.

[0096] The fourth intermediate layer may have the same structure as the second intermediate layer.

[0097] The fourth intermediate layer has a preferred lower limit of thickness of 20 μm. When the thickness of the fourth intermediate layer is 20 μm or more, the edge flatness of the polishing pad or the workpiece during polishing is improved in the polishing process, so that the resulting laminate can further improve the polishing accuracy in the polishing process. The preferred lower limit of the thickness of the fourth intermediate layer is 30 μm, an even more preferred lower limit is 50 μm, and an even more preferred lower limit is 100 μm. Furthermore, from the viewpoint of the balance between handling and edge flatness when re-peeling from the surface plate, the preferred upper limit of the thickness of the fourth intermediate layer is 250 μm, a more preferred upper limit is 220 μm, and an even more preferred upper limit is 190 μm.

[0098] The fourth intermediate layer preferably has a lower limit of 1500 MPa in tensile modulus. When the fourth intermediate layer has a tensile modulus of 1500 MPa or more, the handleability of the resulting laminate when bonded to a surface plate is further improved. Furthermore, the resulting laminate can further improve the polishing accuracy in the polishing process. The lower limit of the tensile modulus of the fourth intermediate layer is more preferably 2000 MPa, even more preferably 3000 MPa, and even more preferably 5000 MPa. Furthermore, if the tensile modulus is too high, it becomes difficult to peel the laminate from the surface plate. Therefore, the upper limit of the tensile modulus of the fourth intermediate layer is preferably 18000 MPa, more preferably 15000 MPa, and even more preferably 8000 MPa. The tensile modulus of the fourth intermediate layer can be measured using the same method as that for the second intermediate layer.

[0099] The T-peel strength when the fourth intermediate layer is peeled from the fourth pressure-sensitive adhesive layer (hereinafter also simply referred to as the "T-peel strength of the fourth intermediate layer") preferably has a lower limit of 5.0 N / 25 mm. When the T-peel strength of the fourth intermediate layer is 5.0 N / 25 mm or more, the resulting laminate can be more effectively prevented from peeling due to shear stress during the polishing process. A more preferred lower limit of the T-peel strength of the fourth intermediate layer is 10 N / 25 mm, an even more preferred lower limit is 15 N / 25 mm, and an even more preferred lower limit is 20 N / 25 mm. There is no particular preferred upper limit for the T-peel strength of the fourth intermediate layer, but a substantial upper limit is 50 N / 25 mm. In particular, when the laminate of the present disclosure does not have the second intermediate layer, it is more preferred that the T-peel strength of the fourth intermediate layer satisfies the above-mentioned range. The T-peel strength of the fourth intermediate layer can be measured by the same method as that for the third intermediate layer.

[0100] The preferred lower limit of the total thickness of the intermediate layer between the foam and the second pressure-sensitive adhesive layer (i.e., if the only intermediate layer between the foam and the second pressure-sensitive adhesive layer is the second intermediate layer or the fourth intermediate layer, the thickness of the second intermediate layer alone or the fourth intermediate layer alone; if both the second intermediate layer and the fourth intermediate layer are present, the total thickness of the second intermediate layer and the fourth intermediate layer) is 20 μm. When the total thickness of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is 20 μm or more, the edge flatness during polishing of the polishing pad or the object to be polished is improved in the polishing step, so that the resulting laminate can further improve the polishing accuracy in the polishing step. The more preferred lower limit of the total thickness of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is 30 μm, even more preferred is 50 μm, and even more preferred is 100 μm. In addition, from the viewpoint that the pressure control on the foam layer of the polishing machine becomes difficult and the edge flatness decreases, the preferred upper limit of the total thickness of the intermediate layer between the foam and the second adhesive layer is 500 μm, a more preferred upper limit is 440 μm, and an even more preferred upper limit is 380 μm.

[0101] The ratio of the foam thickness to the thickness from the foam to the second pressure-sensitive adhesive layer (i.e., the sum of the foam thickness and the thickness of the second pressure-sensitive adhesive layer, the fourth intermediate layer, the fourth pressure-sensitive adhesive layer, and the second intermediate layer on the platen side) is preferably 70% at the lower limit and 95% at the upper limit. By having the foam thickness ratio within the above range, the thickness tolerance of the foam is absorbed, thereby further improving edge flatness. The foam thickness ratio is more preferably 75% at the lower limit and 90% at the upper limit, and even more preferably 80% at the lower limit and 88% at the upper limit.

[0102] In the laminate of the present disclosure, the intermediate layer between the foam and the second pressure-sensitive adhesive layer (i.e., when the only intermediate layer between the foam and the second pressure-sensitive adhesive layer is the second intermediate layer or the fourth intermediate layer, the intermediate layer is the second intermediate layer or the fourth intermediate layer; when both the second intermediate layer and the fourth intermediate layer are present, the intermediate layer is the second intermediate layer and the fourth intermediate layer) has a preferred lower limit of 1500 MPa. Having a tensile modulus of 1500 MPa or more for the intermediate layer between the foam and the second pressure-sensitive adhesive layer further improves the handleability when bonding the obtained laminate to a surface plate. Furthermore, the obtained laminate can further improve the polishing accuracy in the polishing step. A more preferred lower limit for the tensile modulus of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is 2000 MPa, an even more preferred lower limit is 3000 MPa, and an even more preferred lower limit is 5000 MPa. Furthermore, since too high a tensile modulus makes it difficult to peel the film from the surface plate, the upper limit of the tensile modulus of the intermediate layer between the foam and the second pressure-sensitive adhesive layer is preferably 18,000 MPa, more preferably 10,000 MPa, and even more preferably 8,000 MPa. Furthermore, it is more preferable that the tensile moduli of all intermediate layers (i.e., the second intermediate layer and the fourth intermediate layer) between the foam and the second pressure-sensitive adhesive layer each satisfy the above-mentioned range.

[0103] From the viewpoints of flexibility and processability, the intermediate layer between the foam and the second pressure-sensitive adhesive layer (i.e., when the only intermediate layer between the foam and the second pressure-sensitive adhesive layer is the second intermediate layer or the fourth intermediate layer, it is the second intermediate layer or the fourth intermediate layer; when both the second intermediate layer and the fourth intermediate layer are present, it is at least one of the second intermediate layer and the fourth intermediate layer) preferably comprises at least one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a nonwoven fabric. Furthermore, from the viewpoints of flexibility and processability, it is more preferable that all of the intermediate layers between the foam and the second pressure-sensitive adhesive layer (i.e., the second intermediate layer and the fourth intermediate layer) each comprise at least one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a nonwoven fabric.

[0104] The method for producing the laminate of the present disclosure is not particularly limited, and examples thereof include the following method. Specifically, a first pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive solution to the release-treated surface of a release polyethylene terephthalate (PET) film, one surface of which has been subjected to a release treatment, using a doctor knife, and then drying the applied solution. A second pressure-sensitive adhesive layer is then formed using a similar method, and the first pressure-sensitive adhesive layer is then bonded to one surface of a foam, and the second pressure-sensitive adhesive layer is then bonded to the other surface of the foam, thereby obtaining a laminate having a foam, the first pressure-sensitive adhesive layer on one surface of the foam, and the second pressure-sensitive adhesive layer on the other surface of the foam. Furthermore, if necessary, a pressure-sensitive adhesive solution can be applied to the surface of a film that will become an intermediate layer in the laminate of the present disclosure using a doctor knife, and then dried to produce a laminate film (I) having a third pressure-sensitive adhesive layer or a laminate film (II) having a fourth pressure-sensitive adhesive layer, which can then be bonded to the surface of a foam.After that, the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer can be bonded to the laminate film (I) or the laminate film (II) to laminate them together, thereby producing a laminate having a third pressure-sensitive adhesive layer, a third intermediate layer, a fourth pressure-sensitive adhesive layer, or a fourth intermediate layer.

[0105] The laminate of the present disclosure has a preferred lower limit of the total thickness of the laminate of 550 μm and a preferred upper limit of 5000 μm. By having the total thickness of the laminate within the above range, the polishing accuracy in the polishing step is further improved. The more preferred lower limit of the total thickness of the laminate is 700 μm, the more preferred upper limit is 3000 μm, the even more preferred lower limit is 800 μm, and the even more preferred upper limit is 1800 μm.

[0106] The ratio of the foam thickness to the total thickness of the laminate is preferably 5% at the lower limit and 60% at the upper limit. When the ratio of the foam thickness to the total thickness of the laminate is within the above range, the resulting laminate can further improve the polishing accuracy in the polishing step. The ratio of the foam thickness to the total thickness of the laminate is more preferably 10% at the lower limit and 50% at the upper limit, and even more preferably 15% at the lower limit and 45% at the upper limit.

[0107] As described above, the laminate of the present disclosure is used to bond and fix a polishing pad to a surface plate of a polishing machine in a polishing process. The present disclosure also includes a method for fixing a polishing pad, the method comprising a step of bonding a polishing pad to a surface plate of a polishing machine using the laminate of the present disclosure.

[0108] The present disclosure also provides a foam having a 25% compressive strength of 0.18 MPa or more and 3.5 MPa or less, a Shore A hardness of 45 or more and 100 or less, and satisfying the following first or second configuration. First configuration: The foam contains a polyolefin-based foam, and the density of the foam is 185 kg / m ３ More than 500kg / m ３ Second configuration: the foam comprises at least one selected from the group consisting of polyurethane foam, rubber foam, and acrylic foam. The foam of the present disclosure has appropriate flexibility and hardness, and therefore when used in a polishing process, it can improve the flatness of a polishing pad or an object to be polished during polishing, thereby improving polishing precision and yield.

[0109] The foam of the present disclosure has a 25% compressive strength lower limit of 0.18 MPa and an upper limit of 3.5 MPa. When the 25% compressive strength of the foam of the present disclosure is 0.18 MPa or more, the foam does not become too flexible and can suppress excessive elastic deformation. This improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, and the foam of the present disclosure can improve the polishing accuracy in the polishing process. That is, the 25% compressive strength of the foam represents the hardness of the surface and is an important factor in improving in-plane flatness. When the 25% compressive strength of the foam of the present disclosure is 3.5 MPa or less, the foam of the present disclosure has appropriate flexibility, and improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, and the foam of the present disclosure can improve the polishing accuracy in the polishing process. The 25% compressive strength of the foam of the present disclosure preferably has a lower limit of 0.5 MPa, a preferred upper limit of 3.0 MPa, a more preferred lower limit of 1.0 MPa, a more preferred upper limit of 2.5 MPa, an even more preferred lower limit of 1.5 MPa, and a still more preferred upper limit of 2.0 MPa.

[0110] Examples of methods for adjusting the 25% compression strength of the foam of the present disclosure include methods that adjust the strength from the perspective of raw materials such as the type of foam and raw material ratio, the structure, thickness, and density of the foam, and the manufacturing method of the foam. Specifically, from the perspective of the raw materials of the foam, it is conceivable to adjust the 25% compression strength of the foam by adjusting the bulkiness by including an aromatic ring, adjusting the molecular weight, adjusting the glass transition temperature, adjusting the number of functional groups contributing to crosslinking, adjusting the degree of crosslinking, etc. In these cases, the 25% compression strength can be adjusted higher as the foam becomes bulkier, the molecular weight becomes larger, the glass transition temperature becomes higher, the number of functional groups becomes larger, and the degree of crosslinking becomes higher. In terms of the structure, thickness, and density of the foam, it is conceivable to adjust the 25% compression strength of the foam by adjusting the cell size of the foam layer, adjusting the cell shape, adjusting the degree of open cell, and adjusting the presence or absence and thickness of a skin layer, etc. In these cases, it is conceivable to adjust the 25% compression strength of the foam by adjusting the cell size of the foam layer, adjusting the cell shape, adjusting the degree of open cell, adjusting the presence or absence of a skin layer and adjusting its thickness, etc. In these cases, it is conceivable to adjust the 25% compression strength higher as the cell diameter becomes smaller and the skin layer becomes thicker, respectively. From the viewpoint of the manufacturing method of the foam, for example, in the case of polyurethane-based foam, manufacturing methods such as mechanical froth method and chemical foaming method affect the skin layer formed, the cell diameter, the cell shape, etc., so it is considered that the 25% compressive strength of the foam can be adjusted depending on the manufacturing method adopted.

[0111] The foam of the present disclosure has a Shore A hardness of 45 or less, and a Shore A hardness of 100 or less. When the foam of the present disclosure has a Shore A hardness of 45 or more, the foam does not become too flexible and can suppress excessive elastic deformation. This improves the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the foam of the present disclosure to improve the polishing precision in the polishing process. That is, the Shore A hardness of the foam represents the hardness at a point and is an important factor in improving edge flatness, in particular. Increasing the Shore A hardness of the foam can suppress local load deformation on the edge portion, thereby improving edge flatness. When the foam of the present disclosure has a Shore A hardness of 100 or less, the foam has appropriate flexibility, improving the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the foam of the present disclosure to improve the polishing precision in the polishing process. The Shore A hardness of the foam of the present disclosure has a preferred lower limit of 50 and a preferred upper limit of 90, a more preferred lower limit of 60 and a more preferred upper limit of 80, an even more preferred lower limit of 65 and a still more preferred upper limit of 75.

[0112] Methods for adjusting the Shore A hardness of the foam of the present disclosure include, for example, methods that take into account raw materials such as the type and raw material ratio of the foam of the present disclosure, the structure, thickness, and density of the foam of the present disclosure, and the manufacturing method of the foam of the present disclosure. Specifically, from the perspective of the raw materials of the foam of the present disclosure, it is conceivable to adjust the Shore A hardness of the foam of the present disclosure by adjusting the bulkiness by including an aromatic ring, adjusting the molecular weight, adjusting the glass transition temperature, adjusting the number of functional groups contributing to crosslinking, adjusting the degree of crosslinking, etc. In these cases, the Shore A hardness can be adjusted higher as the foam becomes bulkier, the molecular weight becomes larger, the glass transition temperature becomes higher, the number of functional groups becomes larger, and the degree of crosslinking becomes higher. In terms of the structure, thickness, and density of the foam of the present disclosure, it is conceivable to adjust the Shore A hardness of the foam of the present disclosure by adjusting the cell size of the foam layer, adjusting the cell shape, adjusting the degree of open cell, and adjusting the presence or absence and thickness of a skin layer, etc. In these cases, it is conceivable to adjust the Shore A hardness higher as the cell diameter becomes smaller and the skin layer becomes thicker, respectively. In particular, in order to increase the Shore A hardness of the foam of the present disclosure, it is preferable to reduce the cell diameter. From the viewpoint of the manufacturing method of the foam of the present disclosure, for example, in the case of polyurethane foam, manufacturing methods such as mechanical froth method and chemical foaming method affect the skin layer formed, cell diameter, cell shape, etc., so it is considered that the Shore A hardness of the foam of the present disclosure can be adjusted depending on the manufacturing method employed. Furthermore, polyolefin foam may be stretched. Stretching makes it easier to adjust the Shore A hardness of the foam to a high value.

[0113] In the XY plane, where the 25% compressive strength (MPa) is the X coordinate and the Shore A hardness is the Y coordinate, the foam of the present disclosure preferably satisfies 0.18≦X≦3.5 and 1.7ln(X)+48≦Y≦10ln(X)+87. When the foam satisfies 0.18≦X≦3.5 and 1.7ln(X)+48≦Y≦10ln(X)+87, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing step, and the foam can further improve the polishing accuracy in the polishing step.

[0114] The foam of the present disclosure may be a single type of foam or a laminate of two or more types of foam.

[0115] The foam of the present disclosure (hereinafter also referred to as "the foam of the present invention 3") that satisfies the first feature above contains a polyolefin foam. By containing the polyolefin foam, the foam can be appropriately deformed in response to stress applied during polishing, and therefore the foam of the present invention 3 can improve the polishing accuracy in the polishing step.

[0116] Examples of polyolefin resins constituting the polyolefin foam in the foam of the present invention 3 include polyethylene resins, polypropylene resins, and polybutadiene resins. Among these, from the viewpoint of enabling the foam to deform appropriately in response to stress applied during polishing, the polyolefin foam preferably comprises one selected from the group consisting of polyethylene foams composed of polyethylene resins and polypropylene foams composed of polypropylene resins. Examples of the polyethylene foam in the foam of the present invention 3 include foams composed of low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α-olefin copolymers, and mixtures thereof. Examples of the polypropylene foam in the foam of the present invention 3 include foams composed of propylene homopolymers and copolymers of propylene and other olefins.

[0117] The resin constituting the polyolefin foam in the foam of invention 3 may contain components other than the polyolefin resin, as long as the effects of the invention are not impaired. Examples of components other than the polyolefin resin include ethylene-vinyl acetate copolymer (EVA resin).

[0118] The method for producing the foam of the present invention 3 is not particularly limited, and examples thereof include a method in which a resin composition obtained by melt-kneading a polyolefin resin, a blowing agent, etc. is molded by press molding or extrusion molding. Specifically, a polyolefin resin, a blowing agent, and, if necessary, other additives are blended and kneaded to obtain a resin composition, which is then molded into a sheet to produce a foamable resin sheet. Next, the crosslinking reaction of the obtained foamable resin sheet is allowed to proceed, and the sheet is then foamed, thereby producing the foam of the present invention 3.

[0119] The foamable resin sheet can be obtained, for example, by kneading various components using a kneader such as a Banbury mixer or a pressure kneader to obtain a resin composition, and then continuously extruding the resulting composition using an extruder, a calender, conveyor belt casting, or the like.

[0120] Methods for promoting the crosslinking reaction of the foamable resin sheet include crosslinking by ionizing radiation and crosslinking by organic peroxides, with crosslinking by ionizing radiation being preferred. Crosslinking by ionizing radiation can produce foams with small and uniform cell diameters. Examples of ionizing radiation include ultraviolet light, gamma rays, and electron beams. The dose of ionizing radiation is preferably 0.5 to 10 Mrad, more preferably 1.0 to 8.0 Mrad.

[0121] As a method for foaming the foamable resin sheet, a heating method is preferably used, and examples thereof include a batch method such as an oven method, a continuous foaming method in which the foamable resin sheet is formed into a long sheet and continuously passed through a heating furnace, etc. The heating temperature when foaming the foamable resin sheet by heating is preferably 200 to 320°C, more preferably 220 to 300°C.

[0122] The foamable resin sheet may be stretched in at least one of MD and TD, preferably both, during foaming. Stretching in MD and TD can improve the tensile strength of the foamable resin sheet. The foamable resin sheet may be stretched in at least one of MD and TD, preferably both, during or after foaming. When the foamable resin sheet is stretched after foaming, it may be continuously stretched while maintaining the molten state at the time of foaming without being cooled after foaming, or it may be cooled and then heated again to a molten or softened state before stretching.

[0123] The density of the foam of the present invention 3 has a lower limit of 185 kg / m ３ , upper limit 500 kg / m ３ The density of the foam of invention 3 is 185 kg / m ３ As a result, the foam of the present invention 3 does not become too flexible and can suppress excessive elastic deformation, and in the polishing step, the flatness of the polishing pad and the object to be polished during polishing is improved, so the foam of the present invention 3 can improve the polishing accuracy in the polishing step. ３ By setting the density of the foam of the present invention 3 to 200 kg / m or less, the rigidity of the foam of the present invention 3 is not too high, and damage to the object to be polished can be suppressed. ３ , the preferred upper limit is 480 kg / m ３ and a more preferable lower limit is 250 kg / m ３ , and a more preferable upper limit is 460 kg / m ３ and a more preferable lower limit is 300 kg / m ３ , and a more preferable upper limit is 430 kg / m ３ is.

[0124] Examples of methods for adjusting the density of the foam of invention 3 include a method for adjusting the expansion ratio of the foam. When adjusting the expansion ratio of the foam, lowering the expansion ratio of the foam tends to increase the density of the foam.

[0125] The foam of invention 3 preferably has a flat cell structure. By collapsing the cell structure of the foam of invention 3 in the thickness direction and increasing the flatness, when the cell structure is collapsed by pressure applied in the thickness direction during polishing, stress is more likely to escape in a direction perpendicular to the thickness direction, thereby imparting flexibility to the foam. The preferred lower limit of the cell flatness of the foam of invention 3 is 0.2, more preferably 0.4, and even more preferably 0.8. There is no particular preferred upper limit for the cell flatness of the foam of the present disclosure, but the substantial upper limit is 10.

[0126] The method for adjusting the cell flatness of the foam of invention 3 to fall within the above range is not particularly limited, but examples thereof include a method in which the foam is stretched during foaming in the production of a polyolefin foam.

[0127] A foam of the present disclosure satisfying the second feature (hereinafter also referred to as "the foam of invention 4") includes at least one selected from the group consisting of polyurethane foams, rubber foams, and acrylic foams. The polyurethane foam in the foam of invention 4 is not particularly limited as long as it is a foam composed of a polyurethane resin. Examples of the polyurethane resin include those obtained by reacting a polyol compound with a polyisocyanate compound. Examples of the polyol compound include polyester polyols and polyether polyols. Examples of the polyester polyol include condensation polyester polyols, lactone polyester polyols, and polycarbonate polyols obtained by reacting a polycarboxylic acid such as adipic acid or phthalic acid with a polyol such as ethylene glycol, diethylene glycol, propylene glycol, or glycerin. Examples of the polyether polyol include polypropylene glycol, polytetramethylene glycol, and compounds obtained by adding an alkylene oxide to glycerin. Examples of the polyisocyanate compound include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), triphenylmethane triisocyanate, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, and isophorone diisocyanate (IPDI).

[0128] The resin constituting the polyurethane foam in the foam of invention 4 may contain components other than the polyurethane resin, such as titanium oxide and carbon black, within the scope of not impairing the effects of the invention.

[0129] Examples of methods for producing the polyurethane foam in the foam of invention 4 include a method of reacting a foam composition containing the polyol compound, the polyisocyanate compound, and, if necessary, a blowing agent and a catalyst, followed by foaming and curing. Alternatively, a laminate sheet can be produced by reacting the foam composition on a film such as a PET film and laminating a PET film on one side of the foam composition.

[0130] Examples of the foaming agent include water, low-boiling compounds such as methylene chloride, carbon dioxide gas, etc. Examples of the catalyst include tertiary amines such as N,N',N'-trimethylaminoethylpiperazine, triethylenediamine, dimethylethanolamine, N-ethylmorpholine, etc., organometallic compounds such as tin octoate, acetates, alkali metal alcoholates, etc.

[0131] The rubber-based foam in the foam of present invention 4 is not particularly limited as long as it is a foam made of a rubber-based resin, but examples include foams made of natural rubber, foams made of chloroprene rubber, foams made of ethylene propylene rubber, and foams made of synthetic rubber.

[0132] The resin constituting the rubber foam in the foam of invention 4 may contain components other than the rubber resin as long as the effects of the invention are not impaired.

[0133] The acrylic foam in the foam of invention 4 is not particularly limited as long as it is a foam made of an acrylic resin, and examples thereof include FORMAC (manufactured by Sekisui Plastics Co., Ltd.).

[0134] The resin constituting the acrylic foam in the foam of invention 4 may contain components other than the acrylic resin, as long as the effects of the invention are not impaired. Examples of the components other than the acrylic resin include styrene-based resins and olefin-based resins.

[0135] The density of the foam of the present invention 4 has a preferable lower limit of 350 kg / m ３ , the preferred upper limit is 700 kg / m ３The density of the foam is 350 kg / m ３ By satisfying the above conditions, the foam does not become too flexible and excessive elastic deformation can be further suppressed, and in the polishing step, the flatness of the polishing pad and the workpiece during polishing is further improved, so that the foam can further improve the polishing accuracy in the polishing step. ３ When the density of the foam is 400 kg / m or less, the rigidity of the foam does not become too high, and damage to the object to be polished can be further suppressed. ３ , and a more preferable upper limit is 600 kg / m ３ and a more preferable lower limit is 450 kg / m ３ , and a more preferable upper limit is 580 kg / m ３ and an even more preferable lower limit is 475 kg / m ３ , and an even more preferable upper limit is 560 kg / m ３ is.

[0136] Examples of methods for adjusting the density of the foam of the fourth invention include changing the foaming method used in foam production, adjusting the content of the polyisocyanate compound in the foam, etc. When changing the foaming method used in foam production, the density of the foam tends to be higher when a mechanical froth method is used rather than a chemical foaming method, and when adjusting the content of the polyisocyanate compound in the foam, increasing the content of the polyisocyanate compound tends to increase the density of the foam.

[0137] The foam of the present disclosure may have a closed-cell structure or an open-cell structure, preferably an open-cell structure, from the viewpoint of achieving better adhesion between adjacent layers when the foam of the present disclosure is used in a laminate or laminate sheet.

[0138] The preferred thickness of the foam of the present disclosure is 500 μm at the lower limit and 2000 μm at the upper limit. When the thickness of the foam is 500 μm or more, excessive elastic deformation of the foam can be suppressed, improving the flatness of the polishing pad and the workpiece during polishing in the polishing process, thereby enabling the foam to further improve the polishing accuracy in the polishing process. When the thickness of the foam is 2000 μm or less, the foam has appropriate flexibility, improving the edge flatness of the polishing pad and the workpiece during polishing, even in the polishing process of fine workpieces, thereby enabling the foam to further improve the polishing accuracy in the polishing process. The preferred thickness of the foam of the present disclosure is 600 μm at the lower limit and 1800 μm at the upper limit, 700 μm at the lower limit and 1600 μm at the upper limit, and even more preferably 750 μm at the lower limit and 1500 μm at the upper limit.

[0139] The foam of the present disclosure preferably has a thickness tolerance of ±0.1 mm or less. By having the thickness tolerance of the foam within the above range, in a polishing process using the foam, the flatness of the polishing pad or the workpiece during polishing can be more easily adjusted by adjusting the pressure of equipment such as a polishing device. The thickness tolerance of the foam of the present disclosure is more preferably ±0.085 mm or less, even more preferably ±0.06 mm or less, and even more preferably ±0.05 mm or less.

[0140] The foam of the present disclosure has a preferred lower limit of 0.1 mm and an upper limit of 1.2 mm in compression when compressed at 10 N. By setting the compression amount of the foam to 0.1 mm or more when compressed at 10 N, the foam does not become too flexible and does not deform too much under the pressure of the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the foam can further improve the polishing accuracy in the polishing process. By setting the compression amount of the foam to 1.2 mm or less when compressed at 10 N, the foam of the present disclosure has appropriate flexibility and improves the accuracy of pressure control in the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the foam can further improve the polishing accuracy in the polishing process. A more preferred lower limit of the compression amount of the foam when compressed at 10 N is 0.2 mm, a more preferred upper limit is 1.0 mm, an even more preferred lower limit is 0.4 mm, and an even more preferred upper limit is 0.8 mm.

[0141] The preferred lower limit of the compression amount of the foam of the present disclosure when compressed at 200 N is 0.8 mm, and the preferred upper limit is 4.0 mm. By setting the compression amount of the foam when compressed at 200 N to 0.8 mm or more, the foam does not become too flexible and does not deform too much in response to the pressure of the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the foam can further improve the polishing accuracy in the polishing process. By setting the compression amount of the foam when compressed at 200 N to 4.0 mm or less, the foam has appropriate flexibility and improves the accuracy of pressure control in the polishing machine. As a result, the flatness of the polishing pad and the workpiece during polishing is improved in the polishing process, and the foam can further improve the polishing accuracy in the polishing process. The preferred lower limit of the compression amount of the foam when compressed at 200 N is 1.0 mm, and the preferred upper limit is 3.5 mm, and the even more preferred lower limit is 1.5 mm, and the even more preferred upper limit is 3.0 mm.

[0142] The foam of the present disclosure is preferably used in a laminate for bonding and fixing a polishing pad to a platen of a polishing machine in a polishing process.

[0143] The present disclosure also relates to a laminate sheet including the foam of the present disclosure. The laminate sheet of the present disclosure includes a foam having appropriate flexibility and hardness and a PET sheet having appropriate rigidity, and therefore when used in a polishing process, it can improve the flatness of a polishing pad or an object to be polished during polishing, thereby improving polishing precision and yield.

[0144] The laminate sheet of the present disclosure preferably includes a foam containing a polyurethane foam and a PET sheet laminated on the polyurethane foam. The polyurethane foam is not particularly limited as long as it is a foam composed of a polyurethane resin. Examples of the polyurethane resin include those obtained by reacting a polyol compound with a polyisocyanate compound, and specific examples thereof include those similar to those used in the foam of invention 4.

[0145] The PET sheet to be laminated on the polyurethane foam is not particularly limited, but examples thereof include "E5200#50" manufactured by Toyobo Co., Ltd.

[0146] The PET sheet may be laminated on one surface of the polyurethane foam or on both surfaces of the polyurethane foam, and is preferably laminated on one surface of the polyurethane foam from the viewpoint of ease of handling when rolled up.

[0147] The laminate sheet of the present disclosure can be produced by a conventionally known method. Specifically, for example, a foam composition containing the polyol compound, the polyisocyanate compound, and, if necessary, a blowing agent and a catalyst is applied to a PET film, and then reacted, foamed, and cured to produce a laminate sheet in which a PET film is laminated on one side of a polyurethane foam.

[0148] According to the present invention, it is possible to provide a laminate that can improve polishing accuracy and yield in a polishing process. Furthermore, according to the present invention, it is possible to provide a method for fixing a polishing pad using the laminate, and a foam and a laminate sheet that can be used for the laminate.

[0149] FIG. 1 is a schematic diagram showing a method for a retention test.

[0150] The following examples will further illustrate aspects of the present invention, but the present invention is not limited to these examples.

[0151] (Preparation of Pressure-Sensitive Adhesive) (Synthesis of (Meth)acrylic Copolymer) Ethyl acetate was added as a solvent to a reactor equipped with a thermometer, a stirrer, and a cooling tube. The atmosphere was then replaced with nitrogen, and the reactor was heated to initiate reflux. After the solvent boiled, a polymerization initiator solution prepared by diluting 0.2 parts by mass of azobisisobutyronitrile 10 times with ethyl acetate was added. An ethyl acetate solution of the monomer mixture shown in Table 1 was then added dropwise to the reactor from the dropping funnel over 2 hours so that the monomer concentration was 30% by mass. After the completion of the dropwise addition, a polymerization reaction was carried out for 4 hours to obtain a solution containing a (meth)acrylic copolymer. The obtained (meth)acrylic copolymer was diluted 50 times with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm) to prepare a measurement sample. This measurement sample was supplied to a gel permeation chromatograph (manufactured by Waters Corporation, "2690 Separations Module"), and GPC measurement was performed under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C, and the polystyrene-equivalent molecular weight of the (meth)acrylic copolymer was measured, thereby determining the weight average molecular weight.

[0152] (Adhesive A) 40 parts by mass of terpene phenol resin (manufactured by Yasuhara Chemical Co., Ltd., "YS Polystar T130") as a tackifying resin was added to the solution containing the acrylic copolymer obtained in the above-mentioned "(Synthesis of (meth)acrylic copolymer)", and 3.0 parts by mass of Takenate D-101E (manufactured by Mitsui Chemicals, Inc.) as an isocyanate-based crosslinking agent was added, and the mixture was thoroughly stirred to prepare adhesive A.

[0153] (Adhesive B) A (meth)acrylic copolymer was synthesized using the constituent unit monomer ratio shown in Table 1, and an isocyanate-based crosslinking agent was added in an amount of 2.0 parts by mass, thereby preparing adhesive B.

[0154] (Adhesive Agent C) A (meth)acrylic copolymer was synthesized using the constituent unit monomer ratio shown in Table 1, and an isocyanate-based crosslinking agent was added in an amount of 1.5 parts by mass, thereby preparing adhesive Agent C.

[0155] (Adhesive D) The SIS copolymer shown in Table 1 was added to a reactor, and toluene was further added as a solvent so that the total concentration of the SIS copolymer was 50 mass %, followed by thorough stirring. A tackifier resin shown in Table 1 was further added to prepare Adhesive D.

[0156] (Adhesive E) A (meth)acrylic copolymer was synthesized using the constituent unit monomer ratio shown in Table 1, and an isocyanate-based crosslinking agent was added in an amount of 1.0 part by mass, thereby preparing adhesive E.

[0157] (Adhesive F) The SIS copolymer shown in Table 1 was added, and toluene was further added as a solvent so that the total concentration of the SIS copolymer and tackifier resin was 50 mass %, followed by thorough stirring. The tackifier resin shown in Table 1 was further added to prepare Adhesive F.

[0158] (Adhesive G) The SIS copolymer shown in Table 1 was added, and toluene was further added as a solvent so that the total concentration of the SIS copolymer and tackifier resin was 50 mass %, followed by thorough stirring. The tackifier resin shown in Table 1 was further added to prepare Adhesive G.

[0159] The constituent unit monomers of the (meth)acrylic copolymer shown in Table 1 are as follows: BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate Aac: acrylic acid 2HEA: 2-hydroxyethyl acrylate

[0160]

[0161] Example 1 (1) Production of Laminate A solution of adhesive B was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film, one side of which had been subjected to a release treatment. The coating solution was dried by heating at 110°C for 5 minutes to form a first adhesive layer with a thickness of 60 μm. Similarly, a solution of adhesive C was used to form a second adhesive layer with a thickness of 65 μm. The first adhesive layer was bonded to one side of an 800 μm thick polypropylene foam 1 (manufactured by Sekisui Chemical Co., Ltd., "LPMC #4008"), and the second adhesive layer was bonded to the other side to form an integrated laminate. The laminate was then cured in an environment of 40°C for 48 hours to obtain a laminate having a foam, a first adhesive layer on one side of the foam, and a second adhesive layer on the other side of the foam.

[0162] (Examples 2 to 3, Comparative Examples 1, 3, and 5) Laminates were produced in the same manner as in Example 1, except that the foam, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive layer were changed as shown in Tables 2 and 7.

[0163] (Examples 4 to 10, Comparative Examples 2, 4, 6) A first pressure-sensitive adhesive layer was formed and laminated with the foam in the same manner as in Example 1, except that the types of pressure-sensitive adhesive and foam were changed to those shown in Tables 2, 3, and 7. Thereafter, Pressure-sensitive Adhesive C was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film, one side of which had been subjected to a release treatment. The coating solution was dried by heating at 110° C. for 5 minutes to form a fourth pressure-sensitive adhesive layer having the thickness shown in Tables 2, 3, and 7, and then laminated with a fourth intermediate layer shown in Tables 2, 3, and 7. The adhesives shown in Tables 2, 3, and 7 were applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film, one side of which had also been release-treated. The coating solution was dried by heating at 110° C. for 5 minutes to form a 35 μm-thick second adhesive layer, which was then laminated to the side of the fourth intermediate layer opposite to the side on which the fourth adhesive layer was laminated, to produce laminate (b) in which the fourth adhesive layer and the second adhesive layer were laminated on both sides of the fourth intermediate layer. The fourth adhesive layer of laminate (b) was attached to the side of laminate (a) on which the first adhesive layer was not laminated, to obtain a laminate having, in this order, a foam, the first adhesive layer on one side of the foam, the fourth adhesive layer and the fourth intermediate layer on the other side of the foam, and the second adhesive layer as the outermost layer.

[0164] (Examples 11 to 13, 24) A pressure-sensitive adhesive B was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film that had been release-treated on one side, and the coating solution was dried by heating at 110°C for 5 minutes to form a first pressure-sensitive adhesive layer having the thickness shown in Tables 3 and 5, which was then laminated on a third intermediate layer shown in Tables 3 and 5. Similarly, a pressure-sensitive adhesive shown in Tables 3 and 5 was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film that had been release-treated on one side, and the coating solution was dried by heating at 110°C for 5 minutes to form a third pressure-sensitive adhesive layer having the thickness shown in Tables 3 and 5, which was then laminated on the side of the third intermediate layer opposite to the side on which the first pressure-sensitive adhesive layer was laminated, to produce a laminate (c) in which the first pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer were laminated on both sides of the third intermediate layer, respectively. Similarly, a pressure-sensitive adhesive shown in Tables 3 and 5 was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film that had been release-treated on one side, and the coating solution was dried by heating at 110° C. for 5 minutes to form a second pressure-sensitive adhesive layer having the thickness shown in Tables 3 and 5, which was then laminated on a fourth intermediate layer shown in Tables 3 and 5. Similarly, a pressure-sensitive adhesive shown in Tables 3 and 5 was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film that had been release-treated on one side, and the coating solution was dried by heating at 110° C. for 5 minutes to form a fourth pressure-sensitive adhesive layer having the thickness shown in Tables 3 and 5, which was then laminated on the side of the fourth intermediate layer opposite to the side on which the second pressure-sensitive adhesive layer was laminated, to produce a laminate (d) in which the second pressure-sensitive adhesive layer and the fourth pressure-sensitive adhesive layer were laminated on both sides of the fourth intermediate layer, respectively. The third pressure-sensitive adhesive layer of laminate (c) was attached to one side of a foam shown in Tables 3 and 5, and the fourth pressure-sensitive adhesive layer of laminate (d) was attached to the opposite side of the foam, and the resulting mixture was cured in an environment of 40°C for 48 hours, thereby obtaining a laminate having, in this order, the first pressure-sensitive adhesive layer, the third intermediate layer, the third pressure-sensitive adhesive layer, the foam, the fourth pressure-sensitive adhesive layer, the fourth intermediate layer, and the second pressure-sensitive adhesive layer.

[0165] Examples 14 and 19 A first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer were formed in the same manner as in Example 1, except that the type of pressure-sensitive adhesive and the thickness of the pressure-sensitive adhesive layer were changed to those shown in Table 4. Using a laminate sheet shown in Table 4 in which a polyurethane foam and a PET sheet (corresponding to the second intermediate layer) were integrated, the second pressure-sensitive adhesive layer was bonded to the surface of the second intermediate layer of the laminate sheet, and the first pressure-sensitive adhesive layer was bonded to the other surface of the laminate sheet. After lamination and integration, the laminate was cured in an environment of 40°C for 48 hours to obtain a laminate having the first pressure-sensitive adhesive layer, foam, second intermediate layer, and second pressure-sensitive adhesive layer in this order.

[0166] (Examples 15 to 18, 20 to 23, 29, 30) A laminate (e) in which a second pressure-sensitive adhesive layer was laminated on a second intermediate layer was produced in the same manner as in Example 1, except that the laminate sheet in which a polyurethane foam and a PET sheet (corresponding to a second intermediate layer) were integrated, the type of pressure-sensitive adhesive, and the thickness of the pressure-sensitive adhesive layer were changed as shown in Tables 4 to 6. Furthermore, a laminate (f) in which a first pressure-sensitive adhesive layer and a third pressure-sensitive adhesive layer were laminated on both sides of a third intermediate layer, respectively, was produced in the same manner as in Examples 11 to 13 and 24, except that the type of pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive layer, and the type of base material used in the third intermediate layer were changed as shown in Tables 4 to 6. The third adhesive layer of the obtained laminate (f) was bonded to the side of the foam of laminate (e) opposite to the side having the second adhesive layer, and after lamination and integration, the laminate was cured in an environment of 40°C for 48 hours to obtain a laminate having, in this order, the first adhesive layer, the third intermediate layer, the third adhesive layer, the foam, the second intermediate layer, and the second adhesive layer.

[0167] Example 25 A laminate (g) was prepared by laminating a second pressure-sensitive adhesive layer and a foam in the same manner as in Example 1, except that the type of pressure-sensitive adhesive and the foam were changed as shown in Table 5. Furthermore, a laminate (h) was prepared in the same manner as in Examples 11 to 13 and 24, except that the type of pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive layer, and the type of substrate used in the third intermediate layer were changed as shown in Table 5. The third pressure-sensitive adhesive layer of the obtained laminate (h) was bonded to the foam of the laminate (g) to form an integrated laminate, and then cured in an environment of 40°C for 48 hours to obtain a laminate having the first pressure-sensitive adhesive layer, third intermediate layer, third pressure-sensitive adhesive layer, foam, and second pressure-sensitive adhesive layer, in this order.

[0168] Example 26 A laminate (i) in which a first pressure-sensitive adhesive layer and a third pressure-sensitive adhesive layer were laminated on both sides of a third intermediate layer was produced in the same manner as in Examples 11 to 13 and 24, except that the type of adhesive, the thickness of the pressure-sensitive adhesive layer, and the type of base material used in the intermediate layer were changed as shown in Table 6. Furthermore, a laminate (j) in which a second pressure-sensitive adhesive layer and a fourth pressure-sensitive adhesive layer were laminated on both sides of a fourth intermediate layer was produced in the same manner as in Examples 11 to 13 and 24, except that the type of foam, the type of adhesive, the thickness of the pressure-sensitive adhesive layer, and the type of base material used in the intermediate layer were changed as shown in Table 6. The third pressure-sensitive adhesive layer of laminate (i) was attached to the foam side of a laminate sheet formed by integrating a foam and a PET sheet (second intermediate layer) shown in Table 6, and the fourth pressure-sensitive adhesive layer of laminate (j) was attached to the surface on the second intermediate layer side, and the resulting sheet was cured for 48 hours in an environment of 40°C, thereby obtaining a laminate having, in this order, the first pressure-sensitive adhesive layer, the third intermediate layer, the third pressure-sensitive adhesive layer, the foam, the second intermediate layer, the fourth pressure-sensitive adhesive layer, the fourth intermediate layer, and the second pressure-sensitive adhesive layer.

[0169] (Example 27) A laminate was prepared in the same manner as in Example 26, except that the fourth pressure-sensitive adhesive layer of laminate (j) was attached to the foam side of a laminate sheet formed by integrating a polyurethane foam and a PET sheet (corresponding to the first intermediate layer) shown in Table 6, and the third pressure-sensitive adhesive layer of laminate (i) was attached to the surface on the first intermediate layer side.

[0170] Example 28 A laminate (k) having a first pressure-sensitive adhesive layer, a first intermediate layer, and a foam in this order was produced in the same manner as in Example 1, except that the laminate sheet in which a polyurethane foam and a PET sheet (corresponding to a first intermediate layer) were integrated, the type of pressure-sensitive adhesive, and the thickness of the pressure-sensitive adhesive layer were changed as shown in Table 6. Furthermore, a laminate (l) in which a fourth pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer were laminated on both sides of a fourth intermediate layer, respectively, was produced in the same manner as in Examples 4 to 10 and Comparative Examples 2, 4, and 6, except that the type of pressure-sensitive adhesive, the thickness of the pressure-sensitive adhesive layer, and the type of base material used in the intermediate layer were changed as shown in Table 6. The fourth adhesive layer of laminate (l) was bonded to the foam side of laminate (k), and after lamination and integration, the laminate was cured for 48 hours in an environment of 40°C to obtain a laminate having, in this order, a first adhesive layer, a first intermediate layer, a foam, a fourth adhesive layer, a fourth intermediate layer, and a second adhesive layer.

[0171] Comparative Example 7: A solution of adhesive C was applied with a doctor knife to the release-treated surface of a 50 μm polyethylene terephthalate (PET) film, one side of which had been subjected to a release treatment. The coating solution was then dried at 110°C for 5 minutes to form a first adhesive layer with a thickness of 65 μm. Similarly, a second adhesive layer with a thickness of 35 μm was formed using the solution of adhesive C. A 188 μm thick PET film (manufactured by Toyobo Co., Ltd., "A4360") was prepared as an intermediate layer. The first adhesive layer was bonded to one side and the second adhesive layer to the other side. After lamination, the film was aged for 48 hours in an environment of 40°C to obtain a laminate having the first adhesive layer on one side of the intermediate layer and the second adhesive layer on the other side. In Tables 7 and 13, the type and thickness of the intermediate layer used in Comparative Example 7, as well as the tensile modulus described below, are listed in the section for the first intermediate layer.

[0172] (Comparative Example 8) A laminate (n) in which a first pressure-sensitive adhesive layer and a third pressure-sensitive adhesive layer were laminated on both sides of a third intermediate layer was produced in the same manner as in Examples 11 to 13, and 24, except that the type of pressure-sensitive adhesive and the thickness of the pressure-sensitive adhesive layer were changed as shown in Table 7. Furthermore, a laminate (o) in which a fourth pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer were laminated on both sides of a fourth intermediate layer was produced in the same manner as in Examples 4 to 10 and Comparative Examples 2, 4, and 6. The third pressure-sensitive adhesive layer of the obtained laminate (n) was directly bonded to the fourth pressure-sensitive adhesive layer of the laminate (o), and after lamination and integration, the laminate was cured in an environment of 40°C for 48 hours to obtain a laminate having the first pressure-sensitive adhesive layer, third intermediate layer, third pressure-sensitive adhesive layer, fourth pressure-sensitive adhesive layer, fourth intermediate layer, and second pressure-sensitive adhesive layer in this order.

[0173] (2) Measurement of 25% Compression Strength of Foam According to JIS K 6254, a foam was cut into a 30 mm × 30 mm square to prepare a test piece, and the test piece was compressed in the thickness direction at a compression rate of 1 mm / min until the thickness became 25% of the thickness of the test piece before compression, and the stress when compressed was measured, and this stress was taken as the 25% compression strength (MPa). The results are shown in Tables 2 to 7.

[0174] (3) Measurement of Shore A Hardness of Foams According to JIS K 6253, after 24 hours of curing in a laboratory environment, a hardness tester (durometer) was set on a constant pressure loader. Foams were stacked to a thickness of 5 mm or more, and the hardness immediately after stacking was measured using a hardness tester (durometer). For laminates using laminated sheets in which polyurethane foam and PET sheets were integrated, the polyurethane foam and PET were separated using liquid nitrogen, and the hardness of the urethane foam alone was measured. The results are shown in Tables 2 to 7.

[0175] (4) Measurement of foam thickness The thickness (μm) of the foam was measured at 10 points using a displacement meter (Ono Sokki Co., Ltd., "Digital Linear Gauge," measuring terminal 10 mmφ) under a measuring load of 80 g, and the arithmetic mean value was taken as the foam thickness. The results are shown in Tables 2 to 7.

[0176] (5) Measurement of foam density A foam was cut into a size of 10 cm x 10 cm to prepare a test piece, and the density (kg / m) of the foam was measured for the prepared test piece using an electronic hydrometer (manufactured by Mirage, "ED120T") in accordance with JIS K 6767. ３ The results are shown in 2 to 7.

[0177] (6) Measurement of the tensile modulus of the intermediate layer at 23°C In accordance with JIS K 7161, a dumbbell-shaped test specimen was prepared by punching the intermediate layer using a punching blade (manufactured by Kobunshi Keiki Co., Ltd., "Tensile No. 1 Dumbbell"), and the prepared test specimen was pulled to break using a tensile tester (manufactured by Shimadzu Corporation, "Autograph AGS-X") at 23°C and a pulling rate of 100 mm / min, to measure the tensile strength. In the obtained tensile strength-strain curve, the slope of the tensile strength at strains of 1 to 3% was calculated, and this slope was taken as the tensile modulus (MPa). The results are shown in Tables 2 to 7.

[0178] (7) Measurement of 180° Peel Strength of Pressure-Sensitive Adhesive Layer Against SUS at 23°C First, a pressure-sensitive adhesive solution was applied to a 23 μm-thick PET film and dried at 110°C for 5 minutes to prepare a pressure-sensitive adhesive tape for 180° peel strength measurement. Next, a 2 kg rubber roller was used to roll a SUS plate (a SUS304 plate washed with ethanol and then wiped dry) back and forth at a reciprocating speed of 300 mm / min, thereby preparing a measurement sample in which the resulting pressure-sensitive adhesive tape for 180° peel strength measurement was attached to the SUS plate. A 180° peel test was performed on the prepared measurement sample in accordance with JIS Z 0237 using a tensile tester (Shimadzu Corporation, "Autograph AGS-X") at 23°C and a tensile speed of 300 mm / min, in which the pressure-sensitive adhesive tape for 180° peel strength measurement was peeled from the SUS plate, and the 180° peel strength (N / 25 mm) against SUS was measured. The results are shown in Tables 8 to 13.

[0179] (8) Measurement of Compression Amount of Foam According to JIS K 6254, a foam was cut into a 30 mm × 30 mm square shape to prepare a test piece, and the test piece was compressed at a compression rate of 1 mm / min to measure the displacement in the thickness direction of the foam when the compressive stress was 10 N or 200 N, as the compression amount (mm). The results are shown in Tables 8 to 13.

[0180] (9) Measurement of T-peel strength of intermediate layer (9-1) First and second intermediate layers For laminates having a first and / or second intermediate layer, the resulting laminate was cut to a size of 25 mm wide x 100 mm long, and a measurement sample was prepared by making a 10 mm cut with a cutter at both ends of the lengthwise direction at the interface between the intermediate layer (first and second intermediate layers) for which T-peel strength was to be measured and the foam, creating a gripping margin. Using a tensile tester (Shimadzu Corporation, "Autograph AGS-X"), both ends of the lengthwise direction of the cut-in intermediate layer (first and second intermediate layers) in the prepared measurement sample were gripped with the chuck of the tensile tester, and the intermediate layer (first and second intermediate layers) was peeled from the foam at a rate of 300 mm / min, thereby measuring the T-peel strength (N / 25 mm) of each intermediate layer. The results are shown in Tables 10 to 12.

[0181] (9-2) Third and Fourth Intermediate Layers For laminates having a third and / or fourth intermediate layer, the resulting laminate was cut to a size of 25 mm wide x 100 mm long, and a 10 mm cut was made with a cutter at both longitudinal ends of the pressure-sensitive adhesive layer (third and fourth pressure-sensitive adhesive layer) that contacted the intermediate layer (third and fourth intermediate layer) for which the T-peel strength was to be measured, creating a gripping margin to prepare a measurement sample. Using a tensile tester (Shimadzu Corporation, "Autograph AGS-X"), both longitudinal ends of the intermediate layer (third and fourth intermediate layer) to be measured in the prepared measurement sample were gripped with the chuck of the tensile tester, and the intermediate layer (third and fourth intermediate layer) was peeled from the pressure-sensitive adhesive layer (third and fourth pressure-sensitive adhesive layer) at a rate of 300 mm / min, thereby measuring the T-peel strength (N / 25 mm) of each intermediate layer. The results are shown in Tables 8 to 13.

[0182] <Evaluation> The laminates obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 8 to 13.

[0183] (Polishing Precision) (1) Peeling and Scratches During Polishing The release PET film on the second adhesive layer side of the obtained laminate was peeled off, and the second adhesive layer was bonded to the platen of a polishing machine (Kuroda Precision Industries, Ltd., "Nano Metro 300TT-A"). Furthermore, the release PET film on the other side of the laminate bonded to the platen was also peeled off, and a polishing pad made of closed-cell dense polyurethane foam (Nitta DuPont, "IC1000") was bonded to the first adhesive layer of the laminate, thereby bonding and fixing the polishing pad to the platen of the polishing machine via the laminate. A silicon wafer with a diameter of 300 mm, which was the object to be polished, was fixed on the rotating plate of the polishing machine using a rubber roller, and then the silicon wafer was polished for 60 minutes under the following conditions. <Polishing Conditions> - Polishing speed (rotation speed): 30 rpm - Processing pressure: 20 g / cm ３ Slurry type: W2000 (manufactured by Cabot Microelectronics) Slurry supply rate: 100 cc / min

[0184] After polishing the silicon wafer, the composite of the platen of the polishing machine, the laminate, and the polishing pad was visually inspected for peeling of the laminate, and the presence or absence of scratches on the surface of the silicon wafer was observed under a microscope. 10 silicon wafers were used, and this polishing and observation was carried out for each silicon wafer, and the evaluation was carried out according to the following criteria. ○: No peeling (crash) occurred at the interface between the pad-side outermost layer adhesive and the polishing pad, and no peeling (peeling) occurred at the interface between the platen-side outermost layer adhesive and the platen. △: Crash or peeling occurred, but occurred in two or less silicon wafers. ×: Crash or peeling occurred in three or more silicon wafers.

[0185] (2) Edge Flatness The edge flatness of the silicon wafer after polishing in the above "(1) Peeling and Scratches During Polishing" was evaluated using a flatness measuring instrument ("LSW-3010FE" manufactured by Kobelco Giken Co., Ltd.). The measurement was performed on a 296 mm diameter circular silicon wafer after polishing, excluding the outer 2 mm, with a diameter of 300 mm, and a three-dimensional thickness profile image of the wafer was obtained. The profile angle was set to 0°. A two-dimensional profile with the horizontal axis being Location [mm] and the vertical axis being Thickness [μm] was obtained, and the average of the thickness from Location -140 to 140 mm was set as the reference point zero. The absolute value of the maximum amount of displacement of the thickness was measured as +Side between 8 mm from Location 140 to 148 mm, and the absolute value of the maximum amount of displacement of the thickness was measured as -Side between 8 mm from Location -140 to -148 mm, and the judgment was made according to the following criteria. ◎: Both -side and +side were 250 Å or less ○: When the following (1) and (2) were met (1) At least one of -side and +side was larger than 250 Å (2) One of -side and +side was 300 Å or less and the other was 350 Å or less, and the absolute value of the difference between -side and +side was 100 or less ×: When the following (1), (2) or (3) was met (1) At least one of -side and +side was larger than 250 Å (2) One of -side and +side was 300 Å or less and the other was 350 Å or less, and the absolute value of the difference between -side and +side was greater than 100 (3) Both -side and +side were greater than 300 Å

[0186] (Slurry Resistance of Second Pressure-Sensitive Adhesive Layer) (1) Preparation of Samples Before and After Immersion in Chemical Solution For the second pressure-sensitive adhesive layer, a test sample before immersion in a chemical solution was prepared in the same manner as the measurement sample in "(7) Measurement of 180° Peel Strength of Pressure-Sensitive Adhesive Layer from SUS at 23°C" described above. Semi-Sperse 25 (manufactured by Cabot Microelectronics) was diluted 1:1 with ion-exchanged water to prepare an alkaline chemical solution. The obtained test sample before immersion in the chemical solution was immersed in the alkaline chemical solution for 7 days in an atmosphere at 60°C. Thereafter, the test sample was removed from the alkaline chemical solution, washed with ion-exchanged water, and then dried at 23°C for 1 hour to obtain a test sample after immersion in the chemical solution.

[0187] (2) Measurement of the rate of change in 180° peel strength A 180° peel test of the second pressure-sensitive adhesive layer was performed on each test sample before and after chemical immersion using a tensile tester (Shimadzu Corporation, "Autograph AGS-X") under conditions of 23°C, 50% RH, and a peel speed of 300 mm / min, and the 180° peel strength (N / 25 mm) of the second pressure-sensitive adhesive layer from SUS was measured. Using the obtained 180° peel strength from SUS, the rate of change (%) in the 180° peel strength of the second pressure-sensitive adhesive layer before and after chemical immersion was calculated according to the following formula: Rate of change in 180° peel strength (%) = 100 × {(180° peel strength of the second pressure-sensitive adhesive layer from SUS before chemical immersion) - (180° peel strength of the second pressure-sensitive adhesive layer from SUS after chemical immersion)} / (180° peel strength of the second pressure-sensitive adhesive layer from SUS before chemical immersion).

[0188] The slurry resistance of the second pressure-sensitive adhesive layer was evaluated by marking a change rate of 10% or less as "◎", a change rate of more than 10% and less than 20% as "○", and a change rate of more than 20% and less than 30% as "×".

[0189] The foams and intermediate layers used in Tables 2 to 7 are as follows: Polypropylene foam 1 (manufactured by Sekisui Chemical Co., Ltd., "LPMC#04008") Polypropylene foam 2: A foam produced by adjusting the thickness and density of Polypropylene foam 1 to the values ​​in Table 2 Polypropylene foam 3: A foam produced by adjusting the stretch ratio and density of Polypropylene foam 1 to the values ​​in Table 2 Polypropylene foam 4: A foam produced by adjusting the thickness of Polypropylene foam 3 to the value in Table 2 Polypropylene foam 5: A foam produced by adjusting the density of Polypropylene foam 3 to the value in Table 2 Polypropylene foam 6: A foam produced by adjusting the density of Polypropylene foam 1 to the value in Table 2 Polypropylene foam 7 (manufactured by Sekisui Chemical Co., Ltd., "VSC#05008") Polypropylene foam 8: A foam produced by adjusting the density of Polypropylene foam 1 to the value in Table 7 Polyethylene foam 1 (manufactured by Sekisui Chemical Co., Ltd., "Volara WL03") Polyethylene foams 2 and 3: Foams produced by adjusting the thickness and density of Polyethylene foam 1 to the values ​​in Table 3. Polyethylene foam 4 (manufactured by Sekisui Chemical Co., Ltd., "S#05008") Polyurethane foam 1 (manufactured by NHK Spring Co., Ltd., "Nipparei EXT-1.3P") Polyurethane foam 2: Polyurethane foam obtained by adjusting the foam thickness of Polyurethane foam 1 to the value in Table 4. Polyurethane foam 3 (manufactured by NHK Spring Co., Ltd., "Nipparei EXK-1.0P") Polyurethane foams 4 and 5: Polyurethane foams obtained by adjusting the foam thickness of Polyurethane foam 3 to the value in Table 4. Polyurethane foam 6: Polyurethane foam obtained by adjusting the foam density of Polyurethane foam 3 to the value in Table 5. Polyurethane foam 7 (manufactured by Inoac Corporation, "MX-48P") Polyurethane foam 8 (manufactured by Inoac Corporation, "MX-38P") Polyurethane foam 9 (manufactured by Inoac Corporation, "HH-48P") Polyurethane foam 10 (manufactured by Inoac Corporation, "MX-40P") Polyurethane foam 11: a polyurethane foam obtained by adjusting the thickness of the foam in Polyurethane foam 1 to the value shown in Table 4.- Polyurethane foam 12: a polyurethane foam obtained by adjusting the foam thickness of Polyurethane foam 3 to the value shown in Table 4 - PET film 1 (manufactured by Toyobo Co., Ltd., "A4360") - PET film 2 (manufactured by Toyobo Co., Ltd., "E5200#75") - PET film 3 (manufactured by Toyobo Co., Ltd., "E5200#50") - PET film 4 (manufactured by Toyobo Co., Ltd., "E5200#23") - Nonwoven fabric 1 (manufactured by Teijin Frontier Co., Ltd., "05-TH") It should be noted that polyurethane foams 1 to 12 are laminated sheets in which a foam and a PET sheet are integrated.

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[0201]

[0202] According to the present invention, it is possible to provide a laminate that can improve polishing accuracy and yield in a polishing process. Furthermore, according to the present invention, it is possible to provide a method for fixing a polishing pad using the laminate, and a foam and a laminate sheet that can be used for the laminate.

[0203] 1. Adhesive tape 2. SUS plate 3. Weight (1 kg)

Claims

1. A laminate used in a polishing process to bond and fix a polishing pad to a polishing machine surface platen, the laminate comprising a foam, a first adhesive layer attached to one side of the foam to be bonded to the polishing pad, and a second adhesive layer attached to the other side of the foam to be bonded to the polishing machine surface platen, the foam having a 25% compressive strength of 0.18 MPa or more and 3.5 MPa or less, and a Shore A hardness of 45 or more and 100 or less, and satisfying the following first or second configuration: First configuration: the foam contains a polyolefin foam, and the density of the foam is 185 kg / m ３ More than 500kg / m ３ Second configuration: the foam contains at least one selected from the group consisting of a polyurethane foam, a rubber foam, and an acrylic foam.

2. The laminate according to claim 1, wherein in the first configuration, the polyolefin foam comprises at least one selected from the group consisting of polyethylene foam and polypropylene foam.

3. In the second configuration, the density of the foam is 350 kg / m ３ More than 700kg / m ３ 3. The laminate according to claim 1, wherein:

4. The laminate according to claim 1, 2 or 3, wherein the foam satisfies 0.18≦X≦3.5 and 1.7ln(X) + 48≦Y≦10ln(X) + 87 in an XY plane where the 25% compressive strength (MPa) is the X coordinate and the Shore A hardness is the Y coordinate.

5. The laminate according to claim 1, 2, 3 or 4, wherein the foam has a thickness of 500 μm or more and 2000 μm or less.

6. The laminate according to claim 1, 2, 3, 4 or 5, wherein the first adhesive layer has a 180° peel strength at 23°C against SUS of 20 N / 25 mm or more.

7. The laminate according to claim 1, 2, 3, 4, 5 or 6, wherein the thickness of the first adhesive layer is 30 μm or more and 150 μm or less.

8. The laminate according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the second adhesive layer has a 180° peel strength against SUS at 23°C of 5.0 N / 25 mm or more.

9. The laminate according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the thickness of the second adhesive layer is 20 μm or more and 150 μm or less.

10. The laminate of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the laminate has a first intermediate layer between the foam and the first adhesive layer.

11. The laminate according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the laminate has a third adhesive layer between the foam and the first adhesive layer, and a third intermediate layer between the first adhesive layer and the third adhesive layer.

12. The laminate according to claim 10, wherein the laminate has a third adhesive layer between the first intermediate layer and the first adhesive layer, and a third intermediate layer between the first adhesive layer and the third adhesive layer.

13. The laminate of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, wherein the laminate has a second intermediate layer between the foam and the second adhesive layer.

14. The laminate according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, wherein the laminate has a fourth adhesive layer between the foam and the second adhesive layer, and a fourth intermediate layer between the second adhesive layer and the fourth adhesive layer.

15. The laminate according to claim 13, wherein the laminate has a fourth adhesive layer between the second intermediate layer and the second adhesive layer, and a fourth intermediate layer between the second adhesive layer and the fourth adhesive layer.

16. The laminate according to claim 13, 14 or 15, wherein the total thickness of the intermediate layer between the foam and the second adhesive layer is 20 μm or more.

17. The laminate according to claim 13, 14, 15 or 16, wherein the ratio of the thickness of the foam to the thickness from the foam to the second adhesive layer is 70% or more and 95% or less.

18. The laminate according to claim 13, 14, 15, 16 or 17, wherein the intermediate layer between the foam and the second adhesive layer has a tensile modulus of elasticity of 1500 MPa or more.

19. A laminate according to claim 13, 14, 15, 16, 17 or 18, wherein the intermediate layer between the foam and the second adhesive layer comprises at least one material selected from the group consisting of polyethylene terephthalate film, polypropylene film, and nonwoven fabric.

20. A laminate according to claim 10 or 12, wherein the T-peel strength when the first intermediate layer is peeled from the foam is 5.0 N / 25 mm or more.

21. A laminate according to claim 13 or 15, wherein the T-peel strength when the second intermediate layer is peeled from the foam is 5.0 N / 25 mm or more.

22. The laminate according to claim 11 or 12, wherein the T-peel strength when the third intermediate layer is peeled from the third pressure-sensitive adhesive layer is 5.0 N / 25 mm or more.

23. A laminate according to claim 14 or 15, wherein the T-peel strength when the fourth intermediate layer is peeled from the fourth pressure-sensitive adhesive layer is 5.0 N / 25 mm or more.

24. The laminate according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 or 23, wherein the total thickness of the laminate is 550 μm or more and 5000 μm or less.

25. A method for fixing a polishing pad, comprising the step of bonding a polishing pad to a platen of a polishing machine using the laminate of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24.

26. A foam having a 25% compressive strength of 0.18 MPa or more and 3.5 MPa or less, a Shore A hardness of 45 or more and 100 or less, and satisfying the following first or second configuration: First configuration: The foam contains a polyolefin-based foam, and the density of the foam is 185 kg / m ３ More than 500kg / m ３ Second configuration: the foam contains at least one selected from the group consisting of a polyurethane foam, a rubber foam, and an acrylic foam.

27. The foam according to claim 26, wherein in the first configuration, the polyolefin foam comprises at least one selected from the group consisting of polyethylene foam and polypropylene foam.

28. In the second configuration, the density of the foam is 350 kg / m ３ More than 700kg / m ３ 27. The foam of claim 26, wherein:

29. The foam according to claim 26, 27 or 28, having a thickness of 500 μm or more and 2000 μm or less.

30. The foam according to claim 26, 27, 28 or 29, which has a compression amount of 0.1 mm or more and 1.2 mm or less when compressed with 10 N.

31. The foam according to claim 26, 27, 28, 29 or 30, which has a compression amount of 0.8 mm or more and 4.0 mm or less when compressed at 200 N.

32. The foam according to claim 26, 27, 28, 29, 30 or 31, which is used as a laminate for bonding and fixing a polishing pad to a platen of a polishing machine in a polishing process.

33. A laminated sheet comprising the foam of claim 26, 27, 28, 29, 30, 31 or 32.

34. The laminate sheet according to claim 33, comprising: a foam containing polyurethane foam; and a PET sheet laminated to the polyurethane foam.

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