Holding pad and method for manufacturing the holding pad

Abstract

To provide a holding pad that is excellent in both of durability and heat resistance.SOLUTION: A holding pad 110 comprises a sheet 112 having a holding surface P for holding an object to be polished, in which the sheet includes polyurethane resin. The polyurethane resin includes a reaction product of polyol components and polyisocyanate components, and the polyol components include polyether polycarbonate diol represented by the following formula (I), where R1 is a divalent hydrocarbon group with a carbon number of 2-10, a plurality of R1 may be same or different, n is 2-30 and m is 1-20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a support pad and a method for manufacturing the support pad. [Background technology]

[0002] Optical materials, semiconductor wafers, hard disk substrates, glass substrates for liquid crystal displays, semiconductor devices, etc. require extremely precise flatness. In order to polish the surfaces of these various materials to a flat surface, polishing using a polishing pad is performed. Generally, a single-sided polisher is used to polish these objects, which polish each side of the object at a time. In this single-sided polisher, the object is held on a holding platen and polished with a polishing pad attached to the polishing platen. During polishing, a polishing liquid containing abrasive particles is supplied while circulating. Generally, in polishing processes using a single-sided polisher, a holding pad is attached to the holding platen to absorb unevenness on the holding platen and unbalanced loads that occur during polishing processes, and to hold the workpiece to be polished approximately flat on the holding platen.

[0003] A known holding pad is a polyurethane resin sheet having teardrop-shaped bubbles formed by a wet film-forming method, as described in Patent Document 1. Also known is a holding pad including a polyurethane resin sheet having spherical bubbles formed by a dry molding method (molding method), as described in Patent Document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6119049 [Patent Document 2] Patent No. 4775898 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, in order to improve polishing efficiency, there has been a demand for polishing under harsher polishing conditions (high polishing pressure, long polishing times, use of strongly acidic slurries, etc.), and this trend is particularly noticeable when polishing difficult-to-cut materials such as sapphire and GaN. High durability is required for holding pads so that they can be used under such harsh polishing conditions.

[0006] A holding pad containing a polyurethane resin sheet having the above-mentioned approximately spherical bubbles is generally stronger and more durable than a holding pad containing a polyurethane resin sheet having the above-mentioned approximately teardrop-shaped bubbles, and is therefore suitable for use under the above-mentioned harsh polishing conditions. In addition, the holding surface of the holding pad is wetted with water, and the workpiece is attracted to the holding surface by the surface tension of the water. If the holding pad is weak, the holding pad may break when the workpiece is peeled off the holding surface after polishing. From this perspective, a holding pad containing the polyurethane resin sheet with the above-mentioned roughly spherical bubbles, which has high strength, can be said to be useful.

[0007] Furthermore, even when a workpiece is held by a holding pad, lateral shifting of the workpiece may occur during polishing. To prevent such lateral shifting of the workpiece, a frame material with one or more holding holes that surround the outer periphery of the workpiece and can accommodate the workpiece is sometimes attached to the holding surface of the holding pad. Adhesives are used to secure such a frame material to the holding surface of the holding pad or to secure the holding pad to the holding platen. When polishing is performed under such harsh conditions, a heat-sensitive adhesive (hot melt) may be used as the adhesive to firmly bond the frame material to the holding surface of the holding pad and / or the holding pad to the holding platen. When using such a heat-sensitive adhesive, a process of heat-pressing the holding pad together with the frame material and the holding platen at temperatures of approximately 60 to 140°C is essential. Heat is applied to the holding pad during this heat-pressing process. If the holding pad becomes distorted and uneven after heat-pressing, this can adversely affect the polishing of the workpiece. Therefore, heat resistance is also required for the holding pad. As described above, a holding pad including a polyurethane resin sheet having substantially spherical bubbles has relatively high strength. However, such a holding pad tends to warp easily, and from the viewpoint of preventing such warping, it is more important to improve the heat resistance of the holding pad including the polyurethane resin sheet having substantially spherical bubbles.

[0008] As described above, there is a demand for a holding pad that is both highly durable and heat resistant.

[0009] The present invention has been made in view of the above problems, and has as its object to provide a holding pad that is excellent in both durability and heat resistance. [Means for solving the problem]

[0010] As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by using a polyether polycarbonate diol having a specific structure as a raw material for a polyurethane resin, and have thus completed the present invention. Specific aspects of the present invention are as follows:

[0011] [1] A holding pad having a sheet with a holding surface for holding an object to be polished, the sheet comprises a polyurethane resin, the polyurethane resin comprising a reaction product of a polyol component and a polyisocyanate component; The support pad, wherein the polyol component comprises a polyether polycarbonate diol represented by the following formula (I): [ka] (In the above formula (I), R 1 is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 may be the same or different, n is 2 to 30; m is 1 to 20. [2] The support pad according to [1], wherein the sheet has approximately spherical bubbles. [3] The density of the sheet is 0.3 to 0.9 g / cm 3 The holding pad according to [1] or [2], [4] The holding pad according to any one of [1] to [3], wherein the polyether polycarbonate diol has a number average molecular weight of 1,000 to 4,000. [5] The holding pad according to any one of [1] to [4], wherein the content of the polyether polycarbonate diol relative to the total amount of the polyurethane resin is 20% by weight or more. [6] The holding pad according to any one of [1] to [5], wherein the polyether polycarbonate diol contains a structural unit derived from polytetramethylene ether glycol. [7] R in the formula (I) 1 The holding pad according to any one of [1] to [6], wherein is at least one selected from the group consisting of ethylene, isopropylene, and n-butylene. [8] The holding pad according to any one of [1] to [7], wherein the polyisocyanate component contains tolylene diisocyanate. [9] A holding pad described in any one of [1] to [8], wherein the polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of the polyol component and the polyisocyanate component.

[10] The support pad according to [9], wherein the curing agent comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.

[11] A method for producing the holding pad according to any one of [1] to

[10] , comprising the step of forming the sheet by a molding method.

[0012] (definition) In this application, when a numerical range is expressed using "X to Y", the range includes the numerical values ​​X and Y at both ends. [Effects of the Invention]

[0013] The support pad of the present invention is excellent in both durability and heat resistance. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a holder. [Figure 2] FIG. 2 is a cross-sectional view showing the state during polishing. DETAILED DESCRIPTION OF THE INVENTION

[0015] (action) The present inventors have conducted extensive research into the relationship between the polyol component forming the urethane resin and durability and heat resistance, and have unexpectedly discovered that by using the polyether polycarbonate diol represented by the above formula (I) as the polyol component forming the urethane resin, a holding pad excellent in both durability and heat resistance can be obtained. Although the details of why such properties are obtained are not clear, it is presumed as follows.

[0016] The polyether polycarbonate diol represented by the above formula (I) contains carbonate groups, which is thought to result in lower crystallinity than the commonly used polytetramethylene ether glycol (PTMG), and therefore lower crystallinity of the polyurethane resin formed from this polyether polycarbonate diol. It is thought that when the polyurethane resin forming the support surface of the support pad has low crystallinity, its inherent low crystallinity means that there is less change due to the crystalline structure even when heated, making it less likely for the support pad to become distorted by heat pressing. Furthermore, because the polyurethane resin forming the support surface of the support pad contains both ether groups and carbonate groups, the synergistic effect of these groups is thought to result in high durability that allows it to be used even under harsh polishing conditions.

[0017] The holding pad and the method for manufacturing the holding pad according to the present invention will be described below.

[0018] 1. Holding pad and manufacturing method of holding pad FIG. 1 is a schematic cross-sectional view showing an example of a holder according to this embodiment. The holder 100 includes a holding pad 110 and a frame 120 disposed on the holding pad 110. The frame 120 and a sheet 112 are bonded together. In this example, the frame 120 and the sheet 112 are bonded together via an adhesive layer 122. The sheet 112 included in the holding pad 110 contains a polyurethane resin and has a holding surface P on the frame 120 side of the holder 100 for holding a workpiece. Typically, the surface of the sheet 112 opposite the holding surface P has an adhesive layer 116 for fixing the holder 100 to a holding platen of a polishing apparatus and a release paper 114 for protecting the adhesive layer 116 from foreign matter. If necessary, a cushioning layer, a base sheet, or the like may be laminated on the surface of the sheet 112 opposite the holding surface P.

[0019] The sheet 112 has a matrix containing a polyurethane resin and a plurality of pores present in the matrix.

[0020] Open pores may be present in the holding surface P of the sheet 112. To make the open pores present, for example, the mirror layer (skin layer) of the holding surface P may be ground by slicing, buffing, or the like. If open pores are present in the holding surface P, the adhesive force between the holding surface P and the workpiece is reduced, making it easier for the workpiece to rotate on its own axis, which improves the polishing uniformity of the workpiece.

[0021] The thickness of the sheet 112 is not particularly limited, but is preferably 0.4 to 2.5 mm, and more preferably 0.8 to 2.0 mm. When the thickness of the sheet 112 is equal to or greater than the above lower limit, damage to the workpiece to be polished can be more effectively suppressed, and when the thickness is equal to or less than the above upper limit, peeling (breakage) within the sheet 112 during polishing can be more effectively suppressed. The thickness of the sheet 112 is measured in accordance with the measurement method described in JIS K 6550 (1994). That is, when an initial load of 1 cm is applied in the thickness direction of the sheet 112, 2 The thickness is measured when a load of 480 g (100 g in the case of a sheet having approximately teardrop-shaped cells formed by a wet film-forming method) is applied (loaded) to the sheet.

[0022] In the holder 100, a frame member 120 is attached to the holding surface P side of the holding pad 110. The frame member 120 prevents the workpiece from shifting laterally during polishing and jumping out of the polishing area (limiting the range of lateral shift). The frame member 120 may be a member of a conventional holder, and may be made of a material primarily made of a thermosetting resin such as glass epoxy resin (epoxy resin containing glass fiber) or phenolic resin. The shape and dimensions of the frame member 120 are not particularly limited as long as it prevents the workpiece from jumping out of the polishing area. For example, the frame member 120 may have an outer diameter the same as or slightly smaller than that of the sheet 112, an inner diameter slightly larger than the workpiece, and a ring-shaped shape, i.e., a holding hole. For example, a heat-sensitive adhesive (hot melt) can be used for the adhesive layer 122 that bonds the frame material 120 and the holding surface P side of the sheet 112. For example, a thermoplastic adhesive such as an acrylic-based, nitrile-based, nitrile rubber-based, polyamide-based, polyurethane-based, or polyester-based adhesive is used as the heat-sensitive adhesive. When a heat-sensitive adhesive is used to bond the frame material 120 and the holding surface P side of the sheet 112, as described above, the sheet 112 is required to have high heat resistance so as to withstand heat pressing.

[0023] The adhesive layer 116 may also contain an adhesive or pressure-sensitive adhesive that is used in conventionally known holders. Examples of materials for the adhesive layer 116 include various adhesives such as acrylic, nitrile, nitrile rubber, polyamide, polyurethane, and polyester.

[0024] The adhesive layers 116 and 122 in the holder 100 may be derived from a double-sided tape having a base material, may be adhesive tapes with adhesive in sheet form, or may be formed by applying an adhesive. The adhesive layer 116 may have a release paper 114.

[0025] FIG. 2 is a schematic cross-sectional view illustrating a polishing process using the holder 100 of this embodiment. The holder 100 is sandwiched between a holding platen (not shown) and a polishing platen (not shown) together with the workpiece 500 and the polishing pad 510, and a pressing force is applied in the thickness direction. During the polishing process, the holding platen and the polishing platen rotate in the same direction at different rotational speeds, for example. As a result, as shown in FIG. 2, the polishing pad 510 moves in a planar direction (indicated by an arrow in FIG. 2) relative to the holder 100 and the workpiece 500 held by the holder 100 so as to polish the workpiece 500. During the polishing process, the workpiece 500 is polished while moving (rotating) inside the frame material 120.

[0026] The holding pad of the present invention comprises a sheet having a holding surface for holding an object to be polished, the sheet comprises a polyurethane resin, the polyurethane resin comprising a reaction product of a polyol component and a polyisocyanate component; The polyol component comprises a polyether polycarbonate diol represented by formula (I): [ka] (In the above formula (I), R 1 is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 may be the same or different, n is 2 to 30; m is 1 to 20.

[0027] The sheet used for the holding pad may have, but is not particularly limited to, approximately spherical bubbles. In this application, "approximately spherical" is a concept that refers to the normal bubble shape (isotropic, spherical, elliptical, or similar shapes) present in a molded body formed by a dry molding method (molding method), and is clearly distinguished from the bubble shape (anisotropic, approximately teardrop-shaped structure with a diameter increasing from the holding surface of the holding pad to the bottom) present in a molded body formed by a wet film-forming method.

[0028] The density of the sheet used for the holding pad is not particularly limited, but is preferably 0.3 to 0.9 g / cm 3 is preferred, and 0.4 to 0.8 g / cm 3 More preferably, 0.4 to 0.7 g / cm 3 The most preferred density of the sheet is 0.3 g / cm 3 It has excellent durability and is 0.9g / cm 3 Cushioning properties can be ensured by ensuring that the thickness is below this.

[0029] (Polyurethane resin) In the present invention, the polyurethane resin contained in the sheet contains a reaction product of a polyol component and a polyisocyanate component.

[0030] (Polyol component) The polyether polycarbonate diol represented by the above formula (I) is a type of high molecular weight polyol.

[0031] In the above formula (I) representing the polyether polycarbonate diol, R 1 is a divalent hydrocarbon group having 2 to 10 carbon atoms, and R 1 Examples of R include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, 1,1-dimethylethylene, n-pentylene, 2,2-dimethylpropylene, 2-methylbutylene, and combinations of two or more of these, and in particular, at least one selected from the group consisting of ethylene, isopropylene, and n-butylene is preferred. 1 may be the same or different, but are preferably the same. 1 If R has 6 or more carbon atoms, such as n-hexene, the crystallinity of the polyether polycarbonate diol will be high, and the flexibility, elongation, and bending properties of the resulting holding pad at low temperatures will be deteriorated, which is undesirable. 1 is preferably a divalent hydrocarbon group having 2 to 5 carbon atoms.

[0032] In the above formula (I), n is 2 to 30, preferably 3 to 20, and more preferably 3 to 15. In the above formula (I), m is 1 to 20, preferably 1 to 10, and more preferably 2 to 5.

[0033] The polyether polycarbonate diol preferably contains a structural unit derived from polytetramethylene ether glycol, and the number average molecular weight of the structural unit derived from polytetramethylene ether glycol is preferably 100 to 1,500, more preferably 150 to 1,000, and most preferably 200 to 850.

[0034] When the polyether polycarbonate diol contains a structural unit derived from polytetramethylene ether glycol, the structural unit derived from polytetramethylene ether glycol is represented by -(R 1 -O) n It is preferable that the moiety is represented by -.

[0035] The number average molecular weight of the polyether polycarbonate diol is not particularly limited, but is preferably 1000 to 4000, more preferably 1000 to 3000, and most preferably 1500 to 2500. When the number average molecular weight of the polyether polycarbonate diol is 1000 or more, the heat resistance is further improved, and when it is 4000 or less, the durability is further improved.

[0036] The number average molecular weights of the structural units derived from polytetramethylene ether glycol and the polyether polycarbonate diol can be measured as molecular weights converted into polyethylene glycol / polyethylene oxide (PEG / PEO) based on gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Column: Ohpak SB-802.5HQ (exclusion limit 10,000) + SB-803HQ (exclusion limit 100,000) Mobile phase: 5mM LiBr / DMF Flow rate: 0.3ml / min(26kg / cm 2 ) Oven: 60℃ Detector: RI 40℃ Sample volume: 20 μl

[0037] The content of the polyether polycarbonate diol in the entire polyurethane resin is not particularly limited, but is preferably 20% by weight or more, more preferably 20 to 40% by weight, and most preferably 25 to 30% by weight. By making the content 20% by weight or more, it is possible to further improve durability and heat resistance, and by making it 40% by weight or less, cushioning properties are obtained. Here, the weight of the polyurethane resin, which is the basis for the above content, can be calculated as the sum of the weights of the components that are the raw materials for the polyurethane resin. For example, if the polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer, a curing agent, a dispersant (having an active hydrogen group), and a blowing agent (having an active hydrogen group), the weight of the polyurethane resin can be calculated as the sum of the weight of the isocyanate-terminated urethane prepolymer (the sum of the weight of the polyol component and the weight of the polyisocyanate component, which are raw materials), the weight of the curing agent, the weight of the dispersant, and the weight of the blowing agent. The weight of components that do not have functional groups such as NCO and active hydrogen and are not incorporated into the polyurethane resin is not included in the weight of the polyurethane resin.

[0038] Examples of polyol components other than the polyether polycarbonate diol contained in the polyurethane resin include low-molecular-weight polyols, high-molecular-weight polyols other than the polyether polycarbonate diols, and combinations thereof. In some embodiments, the low-molecular-weight polyol is a polyol having a number-average molecular weight of 30 to 300, and the high-molecular-weight polyol is a polyol having a number-average molecular weight of more than 300. The number-average molecular weights of the low-molecular-weight polyol and the high-molecular-weight polyol other than the polyether polycarbonate diol can be measured by the same method as that shown for the number-average molecular weight of the structural unit derived from polytetramethylene ether glycol and the polyether polycarbonate diol.

[0039] Examples of the low molecular weight polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and combinations of two or more of these, and among these, diethylene glycol is preferred.

[0040] Examples of high molecular weight polyols other than the polyether polycarbonate diols include polyether polyols such as polytetramethylene ether glycol (PTMG), polyethylene glycol, and polypropylene glycol; polyester polyols such as a reaction product of ethylene glycol and adipic acid, or a reaction product of butylene glycol and adipic acid; Polycarbonate polyols; Polycaprolactone polyols; or a combination of two or more of these. In some embodiments, it is preferred that the high molecular weight polyol further comprises a polyether polyol.

[0041] The content of low-molecular-weight polyol relative to the total polyurethane resin can be 0 to 20 wt%, 1 to 15 wt%, or 2 to 10 wt%, from the viewpoints of reaction control and control of physical properties such as hardness and elasticity. Alternatively, the content of the low-molecular-weight polyol can be 0 wt% (no low-molecular-weight polyol is included). In this application, "not including" means that a certain component is not intentionally added, and does not exclude its inclusion as an impurity. When the polyurethane resin does not include a low-molecular-weight polyol, the content of the low-molecular-weight polyol relative to the total polyurethane resin can be 0.1 wt% or less, or 0.01 wt% or less.

[0042] The content of the high molecular weight polyol other than the polyether polycarbonate diol relative to the entire polyurethane resin is not particularly limited, but can be 5 to 50% by weight, 10 to 40% by weight, or 15 to 30% by weight. The high molecular weight polyol may also be made of the polyether polycarbonate diol.

[0043] The content of the polyisocyanate component relative to the total polyurethane resin is not particularly limited, but can be 15 to 50% by weight, 20 to 40% by weight, or 25 to 30% by weight.

[0044] (Polyisocyanate component) Polyisocyanate components contained in polyurethane resins include: m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, Diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, p-phenylenediisothiocyanate, xylylene-1,4-diisothiocyanate, ethylidine diisothiocyanate, Or, a combination of two or more of these may be used. Among these, from the viewpoint of the mechanical strength of the resulting holding pad, it is preferable to use tolylene diisocyanates such as 2,6-tolylene diisocyanate (2,6-TDI) and 2,4-tolylene diisocyanate (2,4-TDI).

[0045] In some embodiments, the polyurethane resin can be a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent, in which case the isocyanate-terminated urethane prepolymer is a reaction product of the polyol component and the polyisocyanate component described above.

[0046] The NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is preferably less than 800, more preferably 350 to 700, and most preferably 400 to 600, from the viewpoints of reaction control and hardness.

[0047] The content of the polyether polycarbonate diol relative to the entire isocyanate-terminated urethane prepolymer is not particularly limited, but can be 15 to 75% by weight, 20 to 65% by weight, or 25 to 60% by weight.

[0048] The content of the low-molecular-weight polyol relative to the entire isocyanate-terminated urethane prepolymer is not particularly limited, but can be 0 to 20 wt%, 2 to 15 wt%, or 3 to 10 wt%. Alternatively, the content of the low-molecular-weight polyol can be 0 wt% (no low-molecular-weight polyol is included). When the isocyanate-terminated urethane prepolymer does not contain a low-molecular-weight polyol, the content of the low-molecular-weight polyol relative to the entire isocyanate-terminated urethane prepolymer can be 0.1 wt% or less, or 0.01 wt% or less.

[0049] The content of the high molecular weight polyol other than the polyether polycarbonate diol relative to the entire isocyanate-terminated urethane prepolymer is not particularly limited, but can be 10 to 75% by weight, 15 to 65% by weight, or 20 to 60% by weight. The high molecular weight polyol may also be made of the polyether polycarbonate diol.

[0050] The content of the polyisocyanate component relative to the entire isocyanate-terminated urethane prepolymer is not particularly limited, but can be 20 to 50% by weight, 25 to 45% by weight, or 30 to 40% by weight.

[0051] (hardening agent) Examples of the curing agent contained in the curable resin composition include the amine-based curing agents described below. Examples of polyamines that constitute amine-based curing agents include diamines, such as alkylenediamines such as ethylenediamine, propylenediamine, and hexamethylenediamine; diamines having an aliphatic ring such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; diamines having an aromatic ring such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (hereinafter abbreviated as MOCA); diamines having hydroxyl groups, particularly hydroxyalkyl alkylenediamines, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine; or combinations of two or more of these. Trifunctional triamine compounds and polyamine compounds with four or more functional groups can also be used.

[0052] A particularly preferred curing agent is the above-mentioned MOCA, and the curing agent may consist of MOCA, whose chemical structure is as follows:

[0053] [ka]

[0054] The total amount of curing agent can be adjusted so that the ratio (moles of active hydrogen / moles of NCO) of the sum of the moles of active hydrogen in the curing agent and the moles of active hydrogen in other components (having active hydrogen groups) to the moles of NCO in the isocyanate-terminated urethane prepolymer is preferably 0.7 to 1.1, more preferably 0.75 to 1.05, and most preferably 0.8 to 1.00.

[0055] (Other ingredients) In addition, known additives commonly used in the art, such as blowing agents (water, hollow microspheres, inert gases, etc.), dyes, pigments, foam stabilizers, antioxidants, water repellents, and catalysts, may be added to the curable resin composition.

[0056] The lower limit of the tensile breaking strength at 20°C of the sheet included in the holding pad is not particularly limited, but is preferably 1.00 kg / mm 2 More than 1.10kg / mm 2 or more, or 1.20 kg / mm 2 The upper limit of the tensile strength at 20°C is not particularly limited, but is preferably 2.00 kg / mm 2 Below, 1.80kg / mm 2 or less than 1.60 kg / mm 2 The above lower and upper limits can be combined in any way. The lower limit of the tensile breaking strength at 70°C of the sheet included in the holding pad is not particularly limited, but is preferably 1.20 kg / mm 2 More than 1.30kg / mm 2 or more, or 1.35 kg / mm 2 The upper limit of the tensile strength at 70°C is not particularly limited, but is preferably 2.30 kg / mm 2 Below, 2.10kg / mm 2 or less than 1.90 kg / mm 2 The above lower and upper limits can be combined in any way. Immediately after the start of polishing, the holding pad is operated in an atmosphere at room temperature (about 20°C), and at the end of polishing, the holding pad is heated by the heat generated by polishing and placed in an atmosphere at about 70°C. The tensile breaking strength at 20°C or 70°C is an evaluation item measured taking into account durability in such an atmosphere immediately after the start of polishing and at the end of polishing. The tensile breaking strength at 20°C or 70°C can be measured based on the method and conditions described in "(2) Tensile Breaking Strength" under "Evaluation Method" in the Examples below.

[0057] The upper limit of the distortion of the sheet included in the holding pad after heat pressing is not particularly limited, but can be 3.6 mm or less, 3.3 mm or less, or 3.1 mm or less. The lower limit of the distortion after heat pressing is not particularly limited, but can be 0.5 mm or more, 0.8 mm or more, or 1.0 mm or more. The above lower and upper limits can be combined arbitrarily. The distortion after hot pressing can be measured based on the method and conditions described in "(3) Distortion after hot pressing" in the "Evaluation Method" section of the Examples below.

[0058] (Method of manufacturing the holding pad) In some embodiments, the support pad can be manufactured by a method that includes, but is not limited to, molding the sheet described above.

[0059] The sheet used for the holding pad is not particularly limited, but can be produced by commonly known manufacturing methods such as molding, slab molding, etc. First, a block of polyurethane is formed by such a manufacturing method, and the block is sliced ​​into a sheet, and the sheet formed from the polyurethane resin is molded and laminated to a substrate, etc., to produce a holding pad. Alternatively, the sheet can be molded directly onto a substrate to produce a holding pad.

[0060] The polyurethane resin contained in the sheet can be produced by either the prepolymer method or the one-shot method, but the prepolymer method is preferred from the viewpoint of controlling the reaction. The polyurethane resin is produced by mixing a first component containing an isocyanate group-containing compound and a second component containing an active hydrogen group-containing compound and curing the mixture. In the prepolymer method, the isocyanate-terminated urethane prepolymer serves as the isocyanate group-containing compound, and the chain extender (curing agent) serves as the active hydrogen group-containing compound. In the one-shot method, the isocyanate component serves as the isocyanate group-containing compound, and the chain extender and polyol component serve as the active hydrogen group-containing compounds.

[0061] When the prepolymer method is used, the sheet used for the support pad can be formed by preparing a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and curing the curable resin composition. The curable resin composition can also be a two-component composition prepared by mixing, for example, a liquid A containing an isocyanate-terminated urethane prepolymer and a liquid B containing a curing agent component. The other components can be added to either liquid A or liquid B, but if problems arise, the composition can be further divided into multiple liquids and mixed to form a composition consisting of three or more liquids.

[0062] The sheet used for the support pad can be made of foamed polyurethane resin, which can be produced by a mechanical foaming method, a chemical foaming method, or the like. In addition, foaming of the foamed polyurethane resin can be carried out by dispersing a foaming agent containing hollow microspheres in the polyurethane resin. When a prepolymer method using such a foaming agent is adopted, a curable resin composition containing an isocyanate-terminated urethane prepolymer, a curing agent, and the foaming agent is prepared, and the curable resin composition is foamed and cured to form a molded product. [Example]

[0063] The present invention will be experimentally explained by the following examples, but the following explanation is not intended to limit the scope of the present invention to the following examples.

[0064] (material) The materials used in Examples 1 to 5 and Comparative Example 1 described below are listed below.

[0065] Polyether polycarbonate diol (used as a raw material for isocyanate-terminated urethane prepolymer) PEPCD (1) A polyether polycarbonate diol (represented by the formula (I) above, in which a plurality of R 1All of these are n-butylene, and correspond to polyether polycarbonate diols with n = 3.2 and m = 2.8. Details are shown in Table 1 below. PEPCD(2) to (5): Polyether polycarbonate diols (2) to (5), respectively (details are shown in Table 1 below, similar to the above PEPCD(1)).

[0066] Isocyanate-terminated urethane prepolymer: Prepolymers (1) to (5) - Details are shown in Table 2 below. The numerical value of each component shown in Table 2 means the part by weight of each component when the total urethane prepolymer is taken as 1000 parts by weight. For example, prepolymer (1) shown in Table 2 is a urethane prepolymer with an NCO equivalent of 500, containing 350 parts by weight of 2,4-tolylene diisocyanate as the polyisocyanate component, 386 parts by weight of the above-mentioned PEPCD (1) and 237 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 650 as the high molecular weight polyol component, and 27 parts by weight of diethylene glycol as the low molecular weight polyol component. The contents of 2,4-tolylene diisocyanate, PEPCD (1), polytetramethylene ether glycol having a number average molecular weight of 650, and diethylene glycol relative to the total amount of prepolymer (1) are 35.0% by weight, 38.6% by weight, 23.7% by weight, and 2.7% by weight, respectively.

[0067] [Table 1]

[0068] [Table 2]

[0069] Hardener: MOCA···3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (MOCA) (active hydrogen equivalent = 133.5)

[0070] Additives: Dispersant: Polytetramethylene glycol with a number average molecular weight of 650 (active hydrogen equivalent weight = 325) Blowing agent: Water (active hydrogen equivalent = 9) Foam stabilizer: SH-193 (manufactured by Toray Dow Corning Silicone Co., Ltd.) Catalyst: Toyocat ET (manufactured by Tosoh Corporation)

[0071] Example 1 As shown in Table 2, 1000 g of prepolymer (1) was prepared as component A, 207 g of MOCA, the curing agent, was prepared as component B, and 48 g of dispersant, 0.95 g of blowing agent, 0.95 g of foam stabilizer, and 0.48 g of catalyst were prepared as component C. Note that the amounts are listed in grams to indicate the ratio of each component, but it is sufficient to prepare the required weight (parts) depending on the size of the block. Below, the amounts will also be listed in grams (parts). Components A, B, and C were mixed and stirred, and then degassed under reduced pressure. The degassed components were fed into a mixer to obtain a mixed solution of components A, B, and C. In the resulting mixed solution of components A, B, and C, the ratio of the moles of active hydrogen in the MOCA of component B, the moles of active hydrogen in the dispersant of component C, and the moles of active hydrogen in the blowing agent of component C to the moles of NCO in the prepolymer of component A (total moles of active hydrogen / moles of NCO) was 0.9. The resulting mixture of components A, B, and C was poured into a mold (850 mm x 850 mm square) heated to 80°C and allowed to cure for 30 minutes at 80°C. The resulting resin foam was removed from the mold and allowed to cure for 4 hours at 120°C in an oven. The resulting resin foam was sliced ​​across the thickness to a thickness of 0.4 mm to create a urethane sheet, which was used as a holding pad. The sheet was confirmed to have roughly spherical bubbles. As described above, when the weight of the standard polyurethane resin is taken as the sum of the weights of the monomer components that are the raw materials for the polyurethane resin, and the content of polyether polycarbonate diol relative to the total polyurethane resin is calculated, it is 30.7% by weight as shown in Table 2.

[0072] (Examples 2 to 5, Comparative Example 1) As shown in Table 2, urethane sheets were prepared in the same manner as in Example 1, except that 1000 g of each of prepolymers (2) to (6) was used as component A instead of 1000 g of prepolymer (1) in Example 1, to obtain holding pads for each of Examples 2 to 5 and Comparative Example 1. It was confirmed that these sheets all had approximately spherical air bubbles. In each of Examples 2 to 5 and Comparative Example 1, the ratio of the total number of moles of active hydrogen in MOCA (Component B), the number of moles of active hydrogen in the dispersant (Component C), and the number of moles of active hydrogen in the blowing agent (Component C) to the number of moles of NCO in the prepolymer (Component A) in the mixed solution of Components A, B, and C (total number of moles of active hydrogen / number of moles of NCO) was 0.9. In addition, when the content of polyether polycarbonate diol relative to the total polyurethane resin was calculated for each of Examples 2 to 5 and Comparative Example 1 in the same manner as in Example 1, the values ​​shown in Table 2 were obtained.

[0073] (Evaluation method) The urethane sheets (holding pads) of Examples 1 to 5 and Comparative Example 1 were evaluated for the following (1) density, (2) tensile strength at break, and (3) distortion after hot pressing. The results are shown in Table 3.

[0074] (1) Density Density of urethane sheet (g / cm 3 ) in accordance with the Japanese Industrial Standards (JIS K 6505), a 10cm x 10cm sample piece was cut out from the urethane sheet, its mass was measured, and the density (bulk density) of the elastic resin foam (g / cm) was calculated from the volume calculated from the above size and the above mass. 3 ) was calculated.

[0075] (2) Tensile breaking strength A urethane sheet was punched into a dumbbell shape as specified in the Japanese Industrial Standards (JIS K 6550) to obtain a measurement sample. Both ends of the measurement sample were clamped between the upper and lower air chucks of a tensile tester (Tensilon Universal Tester "RTC-1210", manufactured by A&D Co., Ltd.), and measurement was started at a tensile speed of 100 mm / min with an initial gripping distance of 50 mm. The value at which the measurement value reached its peak (break) was taken as the strength (maximum load). This measurement was carried out three times, and the tensile breaking strength (kgf / mm 2 ) = Strength (Maximum Load) (kgf) / (Thickness (mm) × Sample Width (10 mm)) The tensile breaking strength was calculated based on this formula, and the average value was calculated to obtain the tensile breaking strength (kgf / mm 2 The tensile strength was measured by keeping each measurement sample at 20℃ and 70℃ for 24 hours or more while maintaining the temperature, assuming frictional heat during actual polishing. At both temperatures of 20°C and 70°C during measurement, it can be said that the higher the tensile breaking strength, the more excellent the durability when used as a holding pad.

[0076] (3) Distortion after heat pressing A urethane sheet was cut into a circle with a diameter of 150 mm to prepare a test piece (0.4 mm thick). A heat-sensitive adhesive layer of double-sided tape (442JS, manufactured by 3M, having a heat-sensitive adhesive layer on one side of the base material and a pressure-sensitive adhesive layer on the other side) was temporarily attached to one side of the test piece (corresponding to the side opposite the holding surface), and excess double-sided tape protruding from the test piece was cut off. The test piece with the temporarily attached double-sided tape was then pressed using a heat press at a temperature of 125°C and a pressure of 70 g / cm. 2 The heat-pressed test piece was placed on a flat surface with the double-sided tape side facing down for 10 minutes at a temperature of 20°C, and the height of the part of the test piece that had risen most due to distortion from the flat surface was measured. It can be said that the less distortion there is after the heat press, the more excellent the heat resistance when used as a holding pad.

[0077] [Table 3]

[0078] Examples 1 to 5 relate to holding pads using the polyether polycarbonate diol represented by formula (I), while Comparative Example 1 relates to a holding pad that does not use the polyether polycarbonate diol.

[0079] From the results in Table 3, the holding pads of Examples 1 to 5 have a tensile breaking strength of 1.00 kg / mm ​​at 20°C or 70°C. 2 The holding pads of Examples 1 to 3, in which the number average molecular weight of the polyether polycarbonate diol used was in the range of 1000 to 4000, had a tensile breaking strength of 1.20 kg / mm ​​at 20°C. 2 or more, and the tensile strength at 70°C is 1.35 kg / mm 2 The strain after hot pressing was 3.0 mm or less, which indicates that the film has particularly excellent heat resistance. On the other hand, it was found that the holding pad of Comparative Example 1 had a large distortion after hot pressing and was poor in heat resistance.

[0080] Furthermore, the urethane sheets (holding pads) of Examples 1 to 5 and Comparative Example 1 were also evaluated in the following (4) test of attachment to a polishing device. After evaluation of "(3) Distortion after hot pressing" above, each test piece was attached to the holding platen of a polishing machine (F-REX300X, manufactured by Ebara Corporation) so that the pressure-sensitive adhesive layer on the double-sided tape side of each test piece was in contact with the holding platen. As a result, the test pieces of Examples 1 to 5, which had little warping (distortion), could be fixed to the holding platen without any problems. On the other hand, the test piece of Comparative Example 1 had significant warping and distortion, so air was trapped between the double-sided tape and the holding platen, preventing it from being properly fixed to the holding platen, making it unsuitable as a holding pad.

[0081] From the above, it was found that the support pad containing the polyurethane resin using the polyether polycarbonate diol represented by formula (I) is excellent in both durability and heat resistance. [Explanation of symbols]

[0082] 100...Holder 110···Holding pad 112 seats 114...Release paper 116, 122...adhesive layer 120...Frame material 500...Object to be polished 510···Abrasive pad

Claims

1. A holder comprising a sheet having a holding surface for holding an object to be polished and an adhesive layer containing a heat-sensitive adhesive (hot melt), the sheet comprises a polyurethane resin, the polyurethane resin comprising a reaction product of a polyol component and a polyisocyanate component; The polyol component contains a polyether polycarbonate diol represented by the following formula (I): The retainer, wherein the sheet has substantially spherical bubbles. 【Chemistry 1】 (In the above formula (I), R １ is a divalent hydrocarbon group having 2 to 10 carbon atoms, and a plurality of R １ may be the same or different, n is 2 to 30; m is 1 to 20.

2. A holder as described in claim 1, used in a polishing process in which a polishing liquid containing abrasive particles is supplied while being circulated.

3. The density of the sheet is 0.3 to 0.9 g / cm ３ The holder according to claim 1 or 2, wherein:

4. The holder according to any one of claims 1 to 3, wherein the polyether polycarbonate diol has a number average molecular weight of 1,000 to 4,000.

5. The holder according to any one of claims 1 to 4, wherein the content of the polyether polycarbonate diol relative to the entire polyurethane resin is 20% by weight or more.

6. The holder according to any one of claims 1 to 5, wherein the polyether polycarbonate diol contains structural units derived from polytetramethylene ether glycol.

7. R in the formula (I) １ The holder according to any one of claims 1 to 6, wherein is at least one selected from the group consisting of ethylene, isopropylene, and n-butylene.

8. The holder of any one of claims 1 to 7, wherein the polyisocyanate component comprises tolylene diisocyanate.

9. The holder according to any one of claims 1 to 8, wherein the polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of the polyol component and a polyisocyanate component.

10. The holder of claim 9, wherein the curing agent comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.

11. 11. A method for manufacturing a holder according to claim 1, comprising the step of forming the sheet by a molding method.

Images