Polishing pad, method for manufacturing a polishing pad, and method for manufacturing a polished workpiece

Abstract

To provide a polishing pad and the like capable of reducing frictional resistance between the polishing pad and a polishing object, and imparting excellent flatness to the polishing object.SOLUTION: A polishing pad contains a polyurethane resin. The polyurethane resin comprises: a unit (a) derived from a polysiloxane diol (A) represented by Formula (I); a unit (b) derived from a polyamine (B); and a unit (c) derived from a prepolymer (C) which is different from the polysiloxane diol(A) and has an isocyanate group at an end. Therein, a content of the unit (a) is 0.3 to 20.0 mass% based on 100 mass% of the polyurethane resin. (In Formula (I), Rs each independently represent organic groups having 1 to 10 carbon atoms or a hydrogen atom, and n represents an integer from 5 to 25.)SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an abrasive pad, a method for manufacturing an abrasive pad, and a method for manufacturing an abrasive workpiece. [Background technology]

[0002] Generally, polishing is performed using polishing pads on optical materials such as lenses, parallel plane plates, and reflective mirrors, as well as semiconductor wafers, semiconductor devices, hard disk substrates, metals, and ceramics. Chemical mechanical polishing (CMP) is widely used as a method for such polishing. In general, CMP involves sliding the polishing pad against the surface of the semiconductor wafer to be polished, while simultaneously flowing a polishing solution containing abrasive particles, oxidizing agents, chelating agents, and chemical components such as acids or alkalis onto the surface of the polishing pad as needed.

[0003] Various polishing pads have been proposed for CMP (Chemical Polishing) from the viewpoint of ensuring polishing rate and flatness, and suppressing scratches. For example, Patent Document 1 proposes a polishing pad having a polishing layer made of polyurethane resin foam, wherein the polyurethane resin foam is a reaction-cured product of a polyurethane raw material composition containing an isocyanate-terminated prepolymer containing an isocyanate component, a high molecular weight polyol, and a polysiloxane group-containing diol, and a chain extender. Patent Document 2 also proposes a polishing pad that is a foam-cured product of a urethane resin composition containing a urethane prepolymer having an isocyanate group, which is a reaction product of a polyol containing a polysiloxane compound and polyisocyanate, and a curing agent. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5875300 [Patent Document 2] Patent No. 6424986 [Overview of the project] [Problems that the invention aims to solve]

[0005] According to Patent Document 1, the polishing pad described in the document is highly hydrophobic, improving the slurry discharge of the polishing layer, and reducing the water absorption and swelling properties of the polishing layer. Therefore, it is evaluated that the decrease in polishing speed can be suppressed even when polishing operations are performed for a long time. Furthermore, according to Patent Document 2, the polishing pad described in the document has an excellent polishing rate, and the material polished using such a polishing pad is evaluated as having fewer scratches and producing a polished product with excellent surface smoothness. On the other hand, polishing pads for CMP (Chemical Polishing) are required to have low frictional resistance in addition to the performance described above. If the frictional resistance is too high, the polishing load on the polishing pad will increase, preventing the workpiece from rotating during polishing, which will result in a deterioration of the workpiece's flatness. In addition, there is a concern that the physical properties of the polishing pad will change during polishing due to the frictional heat generated, impairing the polishing characteristics. In the technologies described in Patent Documents 1 and 2, there is still room for improvement from the standpoint of frictional resistance as described above.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a polishing pad, etc., that can reduce the frictional resistance between the polishing pad and the workpiece and can impart good flatness to the workpiece.

[0007] The inventors of the present invention conducted diligent research to solve the above problems and, as a result, discovered that the above problems can be solved by using a polishing pad containing a predetermined component, thus completing the present invention.

[0008] In other words, the present invention encompasses the following embodiments. [1] A polishing pad comprising a resin sheet having a polishing surface, The aforementioned resin sheet contains polyurethane resin, The aforementioned polyurethane resin The unit (a) is derived from polysiloxanediol (A) represented by the following formula (I), Unit (b) derived from polyamine (B), A unit (c) derived from a prepolymer (C) having an isocyanate group at its terminus, which is a reaction product of a polyol compound different from the aforementioned polysiloxanediol (A) and a polyisocyanate compound, It has, An abrasive pad in which the content of unit (a) is 0.3 to 20.0% by mass, with the polyurethane resin being 100% by mass. [ka] (In formula (I), R independently represents an organic group with 1 to 10 carbon atoms or a hydrogen atom, and n represents an integer from 5 to 25.) [2] The polyol compound includes a polysiloxane compound as an optional component. The polishing pad according to [1], wherein the content of the polysiloxane compound is less than 1.0% by mass, with the prepolymer (C) being 100% by mass. [3] The polishing pad according to [1] or [2], wherein the polysiloxanediol (A) comprises polysiloxanediol (A1) in which all of the R in formula (I) are methyl groups. [4] The polishing pad according to any one of [1] to [3], wherein the polyamine (B) comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane. [5] The polishing pad according to any one of [1] to [4], wherein the A hardness of the resin sheet is 50 degrees or higher, and the D hardness of the resin sheet is 60 degrees or lower. [6] The density of the aforementioned resin sheet is 0.3 to 0.6 g / cm³. 3 The polishing pad is one of the following: [1] to [5]. [7] The kinetic friction force of the aforementioned resin sheet is 5.0~5.8 kgf / 100cm 2The polishing pad according to any one of [1] to [6]. [8] The static friction force of the resin sheet is 4.0 to 5.0 kgf / 100 cm 2 The polishing pad according to any one of [1] to [7]. [9] A composition containing a polysiloxanediol (A) represented by the following formula (I), a polyamine (B), and a prepolymer (C) which is a reaction product of a polyol compound and a polyisocyanate compound different from the polysiloxanediol (A) and has an isocyanate group at the terminal, wherein the content of the polysiloxanediol (A) in the composition is 0.3 to 20.0% by mass based on 100% by mass of the composition, and the composition is subjected to a curing reaction to obtain a resin sheet containing a polyurethane resin. A method for producing a polishing pad, which includes a step. [Chemical formula] (In formula (I), each R independently represents an organic group having 1 to 10 carbon atoms or a hydrogen atom, and n represents an integer of 5 to 25.)

[10] A method for producing a polished product, which includes a polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [8] in the presence of a polishing slurry.

[11] The method for producing a polished product according to

[10] , wherein the polished product is a silicon wafer. [Advantages of the Invention]

[0009] According to the present invention, it is possible to provide a polishing pad or the like that can reduce the frictional resistance between the polishing pad and the object to be polished and can impart good flatness to the object to be polished. [Brief Description of the Drawings] [[ID=三十五]] [[ID=三十六]] [[ID=三十七]]

[0010] [[ID=三十八]] [[ID=三十九]] [Figure 1] [[ID=四十]]Figure 1 is a graph showing the measurement results of the flatness of a silicon wafer polished using the polishing pad of Example 1. [[ID=四十一]] [[ID=四十二]] [Figure 2]Figure 2 is a graph showing the measurement results of the flatness of a silicon wafer polished using the polishing pad of Comparative Example 1. [Modes for carrying out the invention]

[0011] The following describes in detail an embodiment of the present invention (hereinafter referred to as "this embodiment"), but the present invention is not limited thereto, and various modifications are possible without departing from its spirit.

[0012] (Polishing pad) The polishing pad of this embodiment is a polishing pad comprising a resin sheet having a polishing surface, wherein the resin sheet contains a polyurethane resin, and the polyurethane resin has units (a) derived from a polysiloxane diol (A) represented by the following formula (I), units (b) derived from a polyamine (B), and units (c) derived from a prepolymer (C) which is a reaction product of a polyol compound different from the polysiloxane diol (A) and a polyisocyanate compound and has an isocyanate group at its terminal, and the content of units (a) is 0.3 to 20.0% by mass, with the polyurethane resin being 100% by mass. Because the polishing pad of this embodiment is configured as described above, the frictional resistance between the polishing pad and the workpiece can be reduced, and good flatness can be imparted to the workpiece.

[0013] The polishing pad of this embodiment comprises at least a predetermined resin sheet having a polishing surface. That is, the polishing pad of this embodiment may consist only of the resin sheet of this embodiment, or it may have components other than the resin sheet. In this embodiment, examples of components other than the resin sheet include various known polishing layers, cushioning layers, and adhesive layers.

[0014] In this embodiment, "resin sheet having an abrasive surface" means that at least one surface of the abrasive pad of this embodiment corresponds to the surface of the resin sheet in this embodiment, and that the surface of the resin sheet becomes the abrasive surface that is pressed against the object to be polished during polishing in this embodiment.

[0015] The polishing pad of this embodiment may have grooves, embossing, and / or holes (punching) on ​​its polishing surface as needed, and may also have light-transmitting portions. There are no particular limitations on the shape of the grooves and embossing; for example, grid-type, concentric circle-type, and radial-type shapes can be used.

[0016] (Resin sheet) (Polyurethane resin) The resin sheet in this embodiment includes a polyurethane resin. That is, the resin sheet in this embodiment can be obtained by molding a polyurethane resin into a sheet. The polyurethane resin in this embodiment has units (a) derived from a polysiloxane diol (A) represented by the above formula (I), units (b) derived from a polyamine (B), and units (c) derived from a prepolymer (C) which is a reaction product of a polyol compound different from the polysiloxane diol (A) and a polyisocyanate compound and has an isocyanate group at its terminal.

[0017] (Unit (a)) In this embodiment, unit (a) is derived from polysiloxanediol (A). In this embodiment, polysiloxanediol (A) can function as a curing agent for the prepolymer (C) described later. Polysiloxanediol (A), represented by the following formula (I), has hydroxyl groups at both ends of its molecular chain. Compared to polysiloxanediols with a hydroxyl group at only one end, it improves the strength of the polishing pad and suppresses changes in the performance of the polishing pad over time during polishing. Furthermore, because the side chain R is an organic group with 1 to 10 carbon atoms or a hydrogen atom, frictional resistance can be reduced without affecting the physical properties or reactivity of conventional polishing pads, meaning that the physical properties and reactivity are easier to control. In particular, since polysiloxanediol (A) constitutes the polyurethane resin separately from the prepolymer (C) described later, a homogeneous polishing pad can be obtained. The reason for this is not intended to be particularly limited, but the inventors speculate as follows: Prepolymers having units derived from polysiloxanediol (A) tend to have increased viscosity, making uniform stirring impossible during the preparation of the polyurethane resin, which can cause inconsistencies in the composition of the polishing pad. In this embodiment, since polysiloxanediol (A) constitutes the polyurethane resin separately from the prepolymer (C) described later, it is presumed that a homogeneous polishing pad can be obtained. Obtaining a homogeneous polishing pad tends to result in uniform frictional resistance within the surface of the polishing, which stabilizes the rotation of the workpiece during polishing and imparts good flatness to the workpiece. [ka]

[0018] In formula (I) above, R independently represents an organic group having 1 to 10 carbon atoms or a hydrogen atom. The organic group having 1 to 10 carbon atoms is not particularly limited, but examples include alkyl groups having 1 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms is not particularly limited, but examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1,2-dimethylpropyl, n-hexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, n-decyl, and the like. In this embodiment, from the viewpoint of suppressing the influence on the physical properties and reactivity of the polishing pad, or making it easier to control the physical properties and reactivity, R is preferably an alkyl group having 1 to 5 carbon atoms, and a methyl group is more preferable. That is, in this embodiment, from the viewpoint of suppressing the influence on the physical properties and reactivity of the polishing pad, or making it easier to control the physical properties and reactions, it is particularly preferable that polysiloxanediol (A) includes polysiloxanediol (A1) in which all of R in formula (I) are methyl groups. R may be the same group or different groups. In the above formula (I), n is an integer of 5 or more from the viewpoint of reducing frictional resistance, and an integer of 25 or less from the viewpoint of making it easier to adjust the various physical properties of the polishing pad. From the same viewpoint as above, it is preferable that n is an integer between 10 and 20.

[0019] Polysiloxanediol (A) itself can be synthesized using various known methods, or it can be obtained as a commercially available product.

[0020] The content of unit (a) is 0.3 to 20.0% by mass, with polyurethane resin being 100% by mass. The above content is 0.3% by mass or more from the viewpoint of reducing frictional resistance, and 20.0% by mass or less from the viewpoint of making it easier to adjust the various physical properties of the polishing pad. If the above content is less than 0.3% by mass, frictional resistance cannot be reduced, and if it is greater than 20.0% by mass, the physical properties and reactivity may fluctuate greatly and become difficult to control, or the polishing rate may decrease due to excessive reduction in frictional resistance, or the compatibility with the adhesive component for fixing the polishing pad to the polishing device may decrease. From the above viewpoint, the above content is preferably 0.3 to 10% by mass, and more preferably 0.3 to 5% by mass. Furthermore, from the same viewpoint as above, the content of units derived from polysiloxane diol (A1) is preferably 0.3 to 20.0% by mass, more preferably 0.3 to 10% by mass, and even more preferably 0.3 to 5% by mass, with polyurethane resin being 100% by mass. The content of unit (a) can be determined from the mixing ratio during the preparation of the polyurethane resin (during the preparation of the composition described later), or it can be determined by analysis using known elemental analysis and structural analysis methods.

[0021] (Unit (b)) In this embodiment, unit (b) is derived from polyamine (B). In this embodiment, the polyamine (B) can function as a curing agent for the prepolymer (C) described later. Polyamine (B) refers to a compound having two or more amino groups in its molecule; for example, diamine compounds can be used. The polyamine compound is not particularly limited, but examples include alkylenediamines such as ethylenediamine, propylenediamine, and hexamethylenediamine; aliphatic ring-containing diamines such as isophoronediamine and dicyclohexylmethane-4,4'-diamine; aromatic ring-containing diamines such as 3,3'-dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (hereinafter also referred to as MOCA); and hydroxyl group-containing diamines such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. Among these, aromatic ring-containing diamines are preferred, and MOCA is more preferred. The polyamine compound may be used alone or in combination of two or more types.

[0022] (Unit (c)) In this embodiment, the unit (c) is derived from the prepolymer (C). Prepolymer (C) is a reaction product of a polyol compound different from polysiloxanediol (A) and a polyisocyanate compound, and has isocyanate groups at its terminals. The molecule of prepolymer (C) contains polyurethane bonds and isocyanate groups.

[0023] Polyisocyanate compounds refer to compounds having two or more isocyanate groups in their molecule. Polyisocyanate compounds are not particularly limited, but examples include diphenylmethane diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, and xylylene-1,4-diisocyanate. Examples include 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, and ethyridine diisothiocyanate. Among these, diisocyanate compounds are preferred, with 2,4-TDI, 2,6-TDI, and MDI being more preferred. Polyisocyanate compounds may be used individually or in combination of two or more.

[0024] Polyol compounds are compounds having two or more alcoholic hydroxyl groups (OH) in their molecule, and differ from polysiloxane diol (A) in that they do not fall under the compound represented by formula (I) above. Polyol compounds are not particularly limited, but examples include diol compounds such as ethylene glycol, diethylene glycol (DEG), and butylene glycol; triol compounds; polyether polyol compounds such as polypropylene glycol (PPG) and poly(oxytetramethylene) glycol (PTMG); polyester polyol compounds such as reaction products of ethylene glycol and adipic acid, or reaction products of butylene glycol and adipic acid; polycarbonate polyol compounds; and polycaprolactone polyol compounds. Furthermore, trifunctional propylene glycol with added ethylene oxide can also be used. The polyol compound may be used alone or in combination of two or more types.

[0025] In this embodiment, the polyol compound preferably contains a polysiloxane compound as an optional component, and the content of the polysiloxane compound is preferably less than 1.0% by mass, with the prepolymer (C) being 100% by mass. When the content is less than 1.0% by mass, a homogeneous polishing pad tends to be obtained. The reason for this is not intended to be particularly limited, but the inventors speculate as follows: The prepolymer (C) having units derived from the polysiloxane compound tends to have increased viscosity, and as a result, uniform stirring cannot be achieved during the preparation process of the polyurethane resin, which can cause inconsistencies in the composition of the polishing pad. Therefore, when the content is less than 1.0% by mass, not only is frictional resistance sufficiently reduced, but a homogeneous polishing pad tends to be obtained as described above. From the same viewpoint as above, the content is preferably less than 0.5% by mass, and more preferably substantially absent (0% by mass).

[0026] (Other ingredients) The resin sheet in this embodiment may contain components derived from additives in addition to polyurethane resin. Such additives are not particularly limited, but examples include defoaming agents, catalysts, foaming agents, foam stabilizers, abrasive grains, dyes, pigments, solid fine particles, flame retardants, hydrophilic agents, hydrophobic agents, lightfast agents, antioxidants, and antistatic agents, which will be described later in the manufacturing method of the polishing pad of this embodiment. As additives, one type may be used alone, or two or more types may be used in combination.

[0027] (Physical properties of resin sheets) (hardness) In this embodiment, from the viewpoint of further improving the flatness of the polished workpiece, it is preferable that the hardness A of the resin sheet is 50 degrees or higher. Furthermore, from the viewpoint of further suppressing scratches on the polished workpiece, the D hardness of the resin sheet in this embodiment is preferably 60 degrees or less, and from the viewpoint of achieving both flatness and scratch suppression, the resin sheet in this embodiment is more preferably A hardness of 50 degrees or more and D hardness of 60 degrees or less. In this embodiment, the resin sheet is particularly preferably made of a D hardness of 30 degrees or more and 60 degrees or less, especially when the polished product is a silicon wafer, from the viewpoint of easily achieving both flatness and scratch suppression. The hardness A and hardness D described above can be measured based on the method described in the examples below. The hardness A and hardness D mentioned above can be adjusted to the specified ranges, for example, by adjusting the amount of polyurethane resin components and foaming agents added.

[0028] (density) In this embodiment, from the viewpoint of further improving the flatness of the polished workpiece, the density of the resin sheet is 0.3 to 0.8 g / cm³. 3 Preferably, it is 0.3 to 0.6 g / cm³. 3 That is the case. The above density can be measured based on the method described in the examples below. The above density can be adjusted to the above range by, for example, adopting the method for manufacturing a polishing pad of the present embodiment described later. For example, in the manufacturing process of the resin sheet in the present embodiment, when the amount of the foaming agent is reduced, the density of the resin sheet tends to increase.

[0029] (Dynamic frictional force) In the present embodiment, from the viewpoint of further improving the flatness of the polished workpiece, the dynamic frictional force of the resin sheet is 5.0 to 5.8 kgf / 100 cm 2 and preferably 5.2 to 5.7 kgf / 100 cm 2 . The above dynamic frictional force can be measured based on the method described in the examples below. The above dynamic frictional force can be adjusted to the above range by, for example, increasing or decreasing the blending amount of polydimethylsiloxane diol (A).

[0030] (Static frictional force) In the present embodiment, from the viewpoint of further improving the flatness of the polished workpiece, the static frictional force of the resin sheet is 4.0 to 5.0 kgf / 100 cm 2 and preferably 4.5 to 5.0 kgf / 100 cm 2 . The above static frictional force can be measured based on the method described in the examples below. The above static frictional force can be adjusted to the above range by, for example, increasing or decreasing the blending amount of polydimethylsiloxane diol (A).

[0031] (Method for manufacturing a polishing pad) The method for manufacturing the polishing pad of this embodiment is not particularly limited as long as it is a method that can produce a polishing pad having the above-described configuration, but it is preferable to manufacture the polishing pad by the following method. That is, the method for manufacturing the polishing pad of this embodiment preferably includes a step of subjecting a composition containing a polysiloxane diol (A) represented by the above formula (I), a polyamine (B), and a prepolymer (C) which is a reaction product of a polyol compound different from the polysiloxane diol (A) and a polyisocyanate compound and has an isocyanate group at the end, to a curing reaction to obtain a resin sheet containing a polyurethane resin.

[0032] (Preparation of composition) The method for manufacturing the polishing pad of this embodiment uses a composition comprising polysiloxanediol (A), polyamine (B), and prepolymer (C). That is, the method for manufacturing the polishing pad of this embodiment may include a step of preparing a composition comprising polysiloxanediol (A), polyamine (B), and prepolymer (C). The polysiloxanediol (A), polyamine (B), and prepolymer (C) that can be used here are as described above.

[0033] In preparing the composition, for example, a prepolymer (C) heated to 30°C to 90°C, polysiloxanediol (A), and polyamine (B) can be placed in a temperature-adjustable jacketed mixer and stirred at 30°C to 130°C. If necessary, the polysiloxanediol (A), polyamine (B), and prepolymer (C) may be placed in a jacketed tank with a stirrer and allowed to mature. The stirring time can be adjusted as appropriate by the number of teeth, rotation speed, and clearance of the mixer, but is typically between 0.1 and 60 seconds.

[0034] The polysiloxanediol (A) and polyamine (B) contained in the composition of this embodiment function as curing agents for the prepolymer (C). On the other hand, the composition of this embodiment may also contain components that function as curing agents (hereinafter also referred to as "other curing agents") in addition to the polysiloxanediol (A) and polyamine (B). Other curing agents are not particularly limited, but examples include hydroxyl group-containing compounds. Hydroxyl group-containing compounds are not particularly limited, but examples include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene Examples include glycols, 3-methyl-4,3-pentanediol, 3-methyl-4,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, trimethylolpropane, trimethylolethane, trimethylolmethane, polytetramethylene glycol, polyethylene glycol, and polypropylene glycol. Other curing agents may be used individually or in combination of two or more types.

[0035] The active hydrogen equivalents (e.g., NH2 equivalents and OH equivalents) of polysiloxane diol (A), polyamine (B), and other curing agents are not particularly limited and may be, for example, 50 to 5000, 100 to 4000, or 130 to 3000. Furthermore, the OH equivalent of curing agents corresponding to hydroxyl group-containing compounds may be 100 to 5000, 200 to 4000, or 300 to 3000. The NH2 equivalent of curing agents corresponding to amino group-containing compounds may be 50 to 2000, 75 to 1000, or 100 to 300.

[0036] In this embodiment, the total amount of polysiloxanediol (A), polyamine (B), and other curing agents used in the composition is preferably determined by the R value, which is the equivalent ratio of active hydrogen groups (amino groups and hydroxyl groups) present in the polysiloxanediol (A), polyamine (B), and other curing agents, when the number of functional groups in the prepolymer (C) is set to 1. In this embodiment, it is preferable that the R value be adjusted to be between 0.7 and 1.2, and more preferably between 0.7 and 1.0.

[0037] The NCO equivalent of prepolymer (C) is preferably 150 to 700, more preferably 200 to 600, and even more preferably 200 to 500. "NCO equivalent" is a numerical value representing the molecular weight of the urethane prepolymer per NCO group, calculated as "(parts by mass of polyisocyanate compound + parts by mass of polyol compound) / [(number of functional groups per molecule of polyisocyanate compound × parts by mass of polyisocyanate compound / molecular weight of polyisocyanate compound)-(number of functional groups per molecule of polyol compound × parts by mass of polyol compound / molecular weight of polyol compound)]".

[0038] The amount of prepolymer (C) used is not particularly limited and may be determined by the R value described above, but is preferably 30 parts by mass or more and 90 parts by mass or less, and more preferably 40 parts by mass or more and 80 parts by mass or less, relative to the total amount of the composition.

[0039] The composition in this embodiment may contain additives other than polysiloxane diol (A), polyamine (B), and prepolymer (C). Examples of additives include solvents (diluents) such as polypropylene glycol; defoamers such as silicone-based defoamers; catalysts; foaming agents such as water or hollow microparticles; foam stabilizers such as silicone-based foam stabilizers; and fillers (abrasives) such as cerium oxide; dyes; pigments; solid microparticles; flame retardants; hydrophilic agents; hydrophobic agents; lightfasteners; antioxidants; and antistatic agents.

[0040] The content of polysiloxane diol (A) in the composition in this embodiment is 0.3 to 20.0% by mass, based on 100% by mass of the composition. From the viewpoint of reducing frictional resistance, the content is 0.3% by mass or more, and from the viewpoint of making it easier to adjust the physical properties of the polishing pad, it is 20.0% by mass or less. If the content is less than 0.3% by mass, it will not be possible to reduce frictional resistance, and if it is greater than 20.0% by mass, the physical properties and reactivity will fluctuate greatly and become difficult to control, or the polishing rate may decrease due to excessive reduction in frictional resistance, or the compatibility with the adhesive component for fixing the polishing pad to the polishing device may decrease. From the above viewpoint, the content is preferably 0.3 to 10% by mass, and more preferably 0.3 to 5% by mass. Furthermore, from the same viewpoint as above, the content of polysiloxane diol (A1) in the composition in this embodiment is preferably 0.3 to 20.0% by mass, more preferably 0.3 to 10% by mass, and even more preferably 0.3 to 5% by mass, based on 100% by mass of the polyurethane resin.

[0041] In the composition of this embodiment, polysiloxanediol (A) is added separately from the prepolymer (C). As a result, a homogeneous polishing pad is obtained. The inventors speculate that the reason for this is as follows, although this is not intended to be a limitation: Prepolymers having units derived from polysiloxanediol (A) tend to have increased viscosity, making it difficult to achieve uniform stirring during the polyurethane resin preparation process, which can cause inconsistencies in the composition of the polishing pad. In this embodiment, since polysiloxanediol (A) is added to the composition separately from the prepolymer (C), it is presumed that a homogeneous polishing pad is obtained.

[0042] (Manufacturing of resin sheets) In this embodiment, the composition obtained as described above is subjected to a curing reaction to obtain a resin sheet containing polyurethane resin. Specifically, for example, the composition according to this embodiment can be poured into a mold preheated to 30°C to 150°C and heated at approximately 30°C to 150°C for approximately 10 minutes to 5 hours. This causes at least the polysiloxane diol (A), polyamine (B), and prepolymer (C) to react and form a polyurethane resin, thereby curing the composition. Furthermore, secondary curing may be performed by heating in an oven at approximately 50°C to 180°C for approximately 10 minutes to 10 hours. The reaction temperature when curing the composition as described above can be appropriately adjusted depending on the type and blending ratio of the polysiloxane diol (A), polyamine (B), and prepolymer (C) used, as well as any additives. By adjusting the reaction temperature, it is possible to control the reaction rate of the curing reaction and thus control the various physical properties of the resulting polishing pad.

[0043] The resin sheet obtained as described above can be cut into resin sheets of an appropriate thickness for use, and the resulting resin sheets may be aged at 30°C to 150°C for about 1 to 24 hours.

[0044] The resin sheet obtained as described above can then be used as a polishing pad in this embodiment by, for example, attaching a means for fixing it to a polishing device, such as double-sided tape, to one side, cutting it into a predetermined shape, preferably a disc shape. The means for fixing it to the polishing device is not particularly limited and can be arbitrarily selected and used from conventionally known double-sided tape, adhesive tape, adhesive, adhesive agent, hook-and-loop fastener, etc.

[0045] Furthermore, the polishing pad of this embodiment may have a single-layer structure consisting only of a resin sheet, or it may have a multi-layer structure in which another layer (cushion layer or substrate layer) is bonded to one side of the resin sheet. In the case of a multi-layer structure, the multiple layers can be bonded and fixed together using double-sided tape or adhesive, while applying pressure as needed. The double-sided tape and adhesive used are not particularly limited and can be arbitrarily selected from conventionally known double-sided tapes and adhesives.

[0046] Furthermore, the polishing pad of this embodiment may be subjected to groove processing, embossing, and / or perforation (punching) on ​​its surface as needed. There are no particular limitations on the shape of the groove processing and embossing; for example, grid-type, concentric circle-type, radial-type shapes can be used.

[0047] Furthermore, the polishing pad may be dressed (grinded) on the surface and / or back surface of the resin sheet. The dressing process is not particularly limited and can be carried out by known methods such as grinding with a diamond dresser.

[0048] (Method of manufacturing polished products) The method for manufacturing a polished workpiece according to this embodiment includes a polishing step of polishing an object to be polished using a polishing pad according to this embodiment in the presence of a polishing slurry to obtain a polished workpiece. The polishing step may be primary polishing (rough polishing), finish polishing, or a step that combines both.

[0049] In the manufacturing method of the polished workpiece of this embodiment, along with the supply of polishing slurry, the workpiece to be polished is pressed toward the polishing pad by the holding platen, and the holding platen and the polishing platen are rotated relative to each other, thereby polishing the workpiece surface by chemical mechanical polishing with the polishing pad. The holding platen and the polishing platen may rotate in the same direction at different rotational speeds, or they may rotate in different directions. Furthermore, the workpiece to be polished may move (rotate) inside the frame during the polishing process.

[0050] The polishing slurry may contain water, an oxidizing agent such as hydrogen peroxide, chemical components such as acidic and alkaline components, additives, and abrasive particles (for example, SiC, SiO2, Al2O3, and CeO2), depending on the workpiece and polishing conditions.

[0051] Furthermore, while there are no particular limitations on the material to be polished, examples include optical materials such as lenses, parallel flat plates, and reflective mirrors, semiconductor wafers, semiconductor devices, hard disk substrates, metals, and ceramics. However, from the viewpoint of the rotational performance of the material to be polished (low frictional resistance with the polishing pad) and the accuracy of the various physical properties of the polishing pad, semiconductor wafers are preferred, and silicon wafers are more preferably used, as they tend to show a more significant improvement in flatness. [Examples]

[0052] The embodiment will be described in more detail below using examples and comparative examples. This embodiment is not limited in any way by the following examples.

[0053] [Example 1] First, 0.82 parts by mass of polysiloxane diol (in formula (I) above, all R are methyl groups, n=13.65; active hydrogen equivalent 588), 1.22 parts by mass of polypropylene glycol as a dispersant (active hydrogen equivalent 1009), 0.08 parts by mass of water as a foaming agent, 0.05 parts by mass of catalyst (manufactured by Tosoh Corporation, product name "Toyocat ET"), and 0.41 parts by mass of silicone-based foam stabilizer were mixed and degassed under reduced pressure to obtain the first mixed solution. Next, 78.18 parts by mass of an isocyanate-terminated urethane prepolymer with an NCO equivalent of 400, containing units derived from 2,4-tolylene diisocyanate (TDI; main component) and a polyol compound (PTMG; weight-average molecular weight 650), was degassed under reduced pressure and then added to the first mixture to obtain the second mixture. Furthermore, 19.24 parts by mass of MOCA were degassed under reduced pressure and then added to the second mixture to obtain the composition according to Example 1. Based on the mixing ratio during composition preparation, the R-value of the composition was calculated to be 0.825. Furthermore, the polysiloxanediol (A) content in the composition was determined to be 0.82% by mass, with the composition as 100% by mass.

[0054] The composition according to Example 1 was poured into a mold (850 mm x 850 mm square) heated to 80°C, and primary cured at 80°C for 40 minutes to obtain a first resin foam. The resin foam was removed from the mold and secondary cured in an oven at 130°C for 8 hours to obtain a second resin foam. The second resin foam was sliced ​​to a thickness of 1.3 mm in the thickness direction to obtain a resin sheet according to Example 1. The obtained resin sheet was used as an abrasive pad according to Example 1 for evaluation described later. Based on the mixing ratio during composition preparation, the content of unit (a) in the polyurethane resin constituting the resin sheet was determined to be 0.82% by mass, with the polyurethane resin content set at 100% by mass.

[0055] [Comparative Example 1] A composition according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the amount of isocyanate-terminated urethane prepolymer used was changed to 78.68 parts by mass, the amount of MOCA used to 19.59 parts by mass, the amount of polysiloxane diol used to 0 parts by mass (not used), the amount of dispersant used to 1.2 parts by mass, and the amount of silicone-based foam stabilizer used to 0.40 parts by mass. The R value of the composition was 0.825.

[0056] The composition according to Comparative Example 1 was processed in the same manner as in Example 1 to obtain a resin sheet according to Comparative Example 1. The obtained resin sheet was used as a polishing pad according to Comparative Example 1 for the evaluation described later.

[0057] [Frictional force] The frictional force of the polishing pads obtained in the examples and comparative examples described later was measured using a universal tensile testing machine (Orientec Co., Ltd. "Tensilon RTC-1210A") under conditions of 25°C and 60% humidity. The polishing pads obtained in the examples and comparative examples described later were cut to a size of 120 mm x 190 mm and used as samples. First, in order to reproduce the slurry wet state during polishing, the samples were subjected to the following pretreatment. That is, the samples were immersed in water for 15 minutes, and then the samples were fixed to the measuring stand of the testing machine with double-sided tape. Water was sprayed five times onto the surface of the fixed sample with a spray bottle, and the surface of the sample was scraped twice with a rubber spatula to homogenize the moisture. Next, a 100mm x 100mm glass plate was placed on top of the pre-treated sample. While applying a 10kg load to the glass plate, the kinetic friction force was measured from the tensile force while the glass plate was pulled 80mm in the shear direction at a tensile speed of 100mm / min. The value at the start of the movement during the measurement of kinetic friction was defined as the static friction force. Five measurements were performed for each example, and the average value was used.

[0058] [density] The density was calculated from the volume and weight of the sample cut from the resin sheet.

[0059] [hardness] Hardness A was measured using a Type A hardness tester (Japanese Industrial Standard, JIS K 7311). Hardness D was measured using a Type D hardness tester (JIS K 7311).

[0060] [Flatness evaluation] Both sides of the silicon wafer were polished using a polishing pad. Specifically, polishing was performed while monitoring the surface shape of the silicon wafer, and polishing was stopped when the average thickness of the silicon wafer was approximately the same as the thickness of the carrier (material holding the material to be polished) and the surface shape was at its best. The conditions for polishing were as follows: (polishing conditions) Material to be polished: Silicon wafer (diameter 300 mmφ, thickness 779 μm) Polishing machine: Speedfam Co., Ltd. "DSM20B-5P-5D" Polishing solution: Alkaline solution manufactured by Fujimi Incorporated (containing colloidal silica; pH 10.5) Lower surface plate rotation speed: 35.0rpm Upper platen rotation speed: -13.4 rpm Internal rotation speed: 7.0 rpm Sun gear rotation speed: 25.0 rp Grinding load: 5287N

[0061] Using the silicon wafers polished as described above, the surface shape (thickness) of the silicon wafers was measured using a flatness measuring device (KOBELCO's "LSW3020FE"), and a graph was obtained. From the obtained graph, the edge shape (edge ​​rounding) was evaluated.

[0062] [Evaluation Results] The results of evaluating the polishing pads for Example 1 and Comparative Example 1 are shown in Table 1 below.

[0063] [Table 1]

[0064] Figure 1 shows the results of measuring the flatness of a silicon wafer polished using the polishing pad of Example 1. In the graph in Figure 1, the horizontal axis represents the distance (mm) from the center of the polished surface of the silicon wafer, and the vertical axis represents the thickness (μm) of the silicon wafer at the corresponding position (the same applies to Figure 2 described later). In Figure 1, there is no sharp drop at both ends of the graph (no edge sagging occurs), and the silicon wafer was evaluated as having good flatness. A sharp drop at both ends of the graph indicates that the thickness at the edges of the silicon wafer is extremely reduced compared to the thickness of other parts (edge ​​sagging occurs).

[0065] Furthermore, when double-sided tape was attached to the polishing pad of Example 1, it was possible to attach it without any problems. This is because the amount of polysiloxane diol used was within the desired range (0.3 to 20.0% by mass per 100% by mass of polyurethane resin, expressed as the content of unit (a)), and therefore, despite the presence of polysiloxane diol, the adhesion was good.

[0066] Figure 2 shows the results of measuring the flatness of a silicon wafer polished using the polishing pad of Comparative Example 1. In Figure 2, the sharp drop at both ends of the graph indicates that edge rounding occurred, and the flatness of the silicon wafer was evaluated as degraded. When double-sided tape was attached to the polishing pad of Comparative Example 1, the adhesion was good, but from the perspective of the edge rounding mentioned above, the performance of the polishing pad was evaluated as insufficient for practical use. [Industrial applicability]

[0067] The polishing pad of the present invention has industrial applicability as a polishing pad used for polishing (particularly chemical mechanical polishing (CMP)) materials such as optical materials like lenses, parallel flat plates, and reflective mirrors, semiconductor wafers, semiconductor devices, hard disk substrates, metals, and ceramics.

Claims

1. A polishing pad comprising a resin sheet having a polishing surface, The aforementioned resin sheet contains polyurethane resin, The aforementioned polyurethane resin The unit (a) is derived from polysiloxanediol (A) represented by the following formula (I), The unit (b) derived from polyamine (B), A unit (c) derived from a prepolymer (C) having an isocyanate group at its terminus, which is a reaction product of a polyol compound different from the polysiloxanediol (A) and a polyisocyanate compound, It has, A polishing pad in which the content of the aforementioned unit (a) is 0.3 to 20.0% by mass, with the polyurethane resin being 100% by mass. 【Chemistry 1】 (In formula (I), R independently represents an organic group having 1 to 10 carbon atoms or a hydrogen atom, and n represents an integer from 5 to 25.)

2. The polyol compound includes a polysiloxane compound as an optional component. The polishing pad according to claim 1, wherein the content of the polysiloxane compound is less than 1.0% by mass, with the prepolymer (C) being 100% by mass.

3. The polishing pad according to claim 1, wherein the polysiloxanediol (A) comprises polysiloxanediol (A1) in which all of the R in formula (I) are methyl groups.

4. The polishing pad according to claim 1, wherein the polyamine (B) comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.

5. The polishing pad according to claim 1, wherein the A hardness of the resin sheet is 50 degrees or higher, and the D hardness of the resin sheet is 60 degrees or lower.

6. The density of the aforementioned resin sheet is 0.3 to 0.6 g / cm³. 3 The polishing pad according to claim 1.

7. The kinetic friction force of the aforementioned resin sheet is 5.0 to 5.8 kgf / 100 cm 2 The polishing pad according to claim 1.

8. The static friction force of the aforementioned resin sheet is 4.0 to 5.0 kgf / 100 cm. 2 The polishing pad according to claim 1.

9. A method for producing an abrasive pad, comprising the steps of subjecting a composition comprising a polysiloxane diol (A) represented by the following formula (I), a polyamine (B), and a prepolymer (C) which is a reaction product of a polyol compound different from the polysiloxane diol (A) and a polyisocyanate compound and has an isocyanate group at its terminal end, to a curing reaction to obtain a resin sheet containing a polyurethane resin. 【Chemistry 2】 (In formula (I), R independently represents an organic group having 1 to 10 carbon atoms or a hydrogen atom, and n represents an integer from 5 to 25.)

10. A method for manufacturing a polished workpiece, comprising a polishing step of polishing an object to be polished using a polishing pad according to any one of claims 1 to 8 in the presence of a polishing slurry.

11. The method for manufacturing a polished product according to claim 10, wherein the polished product is a silicon wafer.

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