Polishing pad, method for manufacturing a polishing pad, and method for polishing the surface of an optical material or semiconductor material.

Abstract

To provide a polishing pad which is excellent in step dissolution performance and can suppress dishing and defect, and provide a method for manufacturing the polishing pad, and a method for polishing a surface of an optical material or a semiconductor material using the polishing pad.SOLUTION: A polishing pad has a polishing layer containing a polyurethane resin, wherein the polyurethane resin is a cured product of a curable resin composition containing an isocyanate terminal urethane prepolymer and a curing agent; the isocyanate terminal urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component; and the curing agent contains an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the following formula (I). In the formula (I), R1 is a divalent hydrocarbon group having 2 to 10 carbon atoms; the plurality of R1 may be the same or different; n is 2 to 30; and m is 0.1 to 20.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polishing pad, a method for manufacturing a polishing pad, and a method for polishing the surface of an optical material or a semiconductor material. The polishing pad of the present invention is used for polishing optical materials, semiconductor wafers, semiconductor devices, hard disk substrates, etc., and is particularly suitable for polishing devices on which an oxide layer, a metal layer, etc., is formed on a semiconductor wafer. [Background technology]

[0002] Optical materials, semiconductor wafers, hard disk substrates, LCD glass substrates, and semiconductor devices require extremely precise flatness. Hard polishing pads are commonly used to polish the surfaces of these various materials, especially the surfaces of semiconductor devices, to a flat surface. Currently, the abrasive layer in many hard polishing pads typically uses a hard polyurethane material obtained by curing an isocyanate-terminated urethane prepolymer, which is a reaction product of an isocyanate component such as tolylene diisocyanate (TDI) and a polyol component containing a high molecular weight polyol such as polytetramethylene ether glycol (PTMG), with a curing agent such as 3,3'-dichloro-4,4'-diaminodiphenylmethane. The high molecular weight polyol that forms the isocyanate-terminated urethane prepolymer forms the soft segment of the polyurethane, and PTMG has traditionally been commonly used as the high molecular weight polyol due to its ease of handling and appropriate rubber elasticity.

[0003] In the polishing of semiconductor devices, the miniaturization and increasing density of integrated circuits in recent years have led to a demand for more stringent levels of performance in eliminating steps on the surface of the workpiece and suppressing defects such as scratches. If the performance in eliminating steps on the surface of the workpiece is insufficient, a phenomenon called dishing, in which the cross-section of the wiring becomes concave in a dish-like shape, mainly in wide wiring patterns, is likely to occur, and the local flatness of the workpiece surface deteriorates.

[0004] Conventional polishing pads using PTMG as a high molecular weight polyol are sometimes insufficient in terms of step-leveling performance and defect suppression, and studies are being conducted on using polyols other than PTMG as high molecular weight polyols.

[0005] Patent Document 1 discloses that a polishing pad formed using polypropylene glycol (PPG) as the high molecular weight polyol for the isocyanate-terminated urethane prepolymer exhibits excellent step-leveling performance and low defect occurrence. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-157415 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, if the entire amount of high molecular weight polyol is PPG, as in the polishing pad described in Patent Document 1, the wear resistance of the polishing layer may be poor, resulting in a shorter lifespan for the polishing pad. Furthermore, if the entire amount of high molecular weight polyol is PPG, as in the polishing pad described in Patent Document 1, the resulting isocyanate-terminated urethane prepolymer tends to soften. To prevent this, it becomes necessary to adjust the equivalent amounts of the polyol component and the polyisocyanate component during the production of the isocyanate-terminated urethane prepolymer.

[0008] As described above, there is a need for a polishing pad that excels in eliminating steps, suppresses dishing, and suppresses defects.

[0009] This invention has been made in view of the above-mentioned problems, and aims to provide a polishing pad that has excellent step-leveling performance, can suppress dishing, and can suppress defects. [Means for solving the problem]

[0010] The present inventors, through diligent research to solve the above problems, discovered that the above problems can be solved by using a combination of an amine-based curing agent and a polyether polycarbonate diol curing agent represented by a specific structural formula, and thus completed the present invention. Specific aspects of the present invention are as follows.

[0011] [1] A polishing pad having a polishing layer containing polyurethane resin, The polyurethane resin is a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component. The curing agent comprises an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the following formula (I), the polishing pad: [ka] (In the above formula (I), R 1 It is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 They may be the same or they may be different. n is between 2 and 30. m is between 0.1 and 20. [2] The polishing pad according to [1], wherein the polyether polycarbonate diol curing agent comprises structural units derived from polytetramethylene ether glycol. [3] The polishing pad according to [1] or [2], wherein the weight ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent is 8:2 to 2:8. [4] The polishing pad according to any one of [1] to [3], wherein the molar ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent is 9:1 to 5:5. [5] R in equation (I) above 1The polishing pad according to any one of [1] to [4], which is at least one selected from the group consisting of ethylene, isopropylene, and n-butylene. [6] The polishing pad according to any one of [1] to [5], wherein the number average molecular weight of the polyether polycarbonate diol curing agent is 500 to 2500. [7] The polishing pad according to any one of [1] to [6], wherein the amine curing agent contains 3,3'-dichloro-4,4'-diaminodiphenylmethane. [8] The polishing pad according to any one of [1] to [7], wherein the polyisocyanate component contains tolylene diisocyanate. [9] The polishing pad according to any one of [1] to [8], wherein the curable resin composition further contains micro hollow spheres.

[10] A method for manufacturing the polishing pad according to any one of [1] to [9], the method including a step of forming the polishing layer.

[11] A method for polishing the surface of an optical material or a semiconductor material, the method including a step of polishing the surface of the optical material or the semiconductor material using the polishing pad according to any one of [1] to [9].

[0012] (Definition) In the present application, when representing a numerical range using "X to Y", the range shall include the numerical values X and Y at both ends.

Advantages of the Invention

[0013] The polishing pad of the present invention is excellent in step elimination performance, can suppress dishing, and can suppress defects.

Brief Description of the Drawings

[0014] [Figure 1] Figures (a) to (c) of FIG. 1 are schematic views showing the state in which steps are eliminated by polishing. [Figure 2] FIG. 2 is a graph showing the relationship between the polishing amount and the steps. [Figure 3]Figures 3(a) and 3(b) are graphs showing the evaluation results of the step-elimination performance of the polishing pads of Examples 1, 7, and 11 and Comparative Examples 1 to 3. [Figure 4] Figures 4(c) and 4(d) are graphs showing the evaluation results of the step-elimination performance of the polishing pads of Examples 1, 7, and 11 and Comparative Examples 1 to 3. [Figure 5] Figure 5 is a graph showing the defect evaluation results for the polishing pads of Examples 1, 7, and 11 and Comparative Examples 1 to 3. [Modes for carrying out the invention]

[0015] (action) The inventors diligently researched the relationship between the curing agent for forming the polishing layer, step-reducing performance, and defects. Unexpectedly, they discovered that by using a combination of an amine-based curing agent and a polyether polycarbonate diol curing agent represented by a specific structural formula, a polishing pad with excellent step-reducing performance, suppression of dishing, and suppression of defects can be obtained. The detailed reasons for obtaining these properties are not clear, but they are presumed to be as follows.

[0016] Because polyether polycarbonate diol curing agents contain carbonate groups, they are thought to have lower crystallinity compared to PTMG and the like. Therefore, when polyether polycarbonate diol curing agents are used in addition to conventional amine-based curing agents, the crystallinity of the resulting polished layer is also thought to be lower. Lower crystallinity of the polished layer makes it less likely for polishing debris to aggregate and form large clumps. As a result, it is presumed that the step-leveling performance of the polished object will be improved, dishing will be suppressed, and defects will be reduced.

[0017] (Leveling performance) In semiconductor manufacturing processes, the damascene process is used to produce metal (Cu) wiring. In this process, grooves are cut into an insulating film on a silicon wafer, metal is embedded in these grooves by sputtering or other methods, and excess metal is removed by chemical mechanical polishing (CMP) to form metal wiring. To eliminate the physical or chemical stress that occurs between the insulating film and the metal, the insulating film is usually coated with a barrier metal before the metal is embedded.

[0018] Schematic diagrams of experiments evaluating the step-elimination performance are shown in Figures 1(a) to 1(c). Figure 1(a) shows the state before polishing begins. As shown in Figure 1(a), when a metal film (Cu film) 20 is embedded in the grooves of the insulating film (oxide film) 10, a step (difference in thickness between the part with grooves and the part without grooves) 40 is created between the part with grooves and the part without grooves, depending on the width of the grooves present beneath the metal film 20. In Figure 1(a), the thickness 30 of the metal film 20 in the part without grooves is 8000 Å, and the step 40 is 3500 Å. Figure 1(b) shows the state after polishing amount is 2000 Å, and the step 41 is 2000 Å. Figure 1(c) shows the state after polishing amount is 6000 Å, and the step 42 is almost 0.

[0019] In this application, "step reduction performance" refers to the ability to reduce the steps (unevenness) of a pattern wafer when polished. Figure 2 shows a graph illustrating the relationship between the amount of polishing (Å) and the step height (Å) when using polishing pad A (dotted line), which has high step height reduction performance, and polishing pad B (solid line), which has relatively low step height reduction performance, on a workpiece in the state shown in Figure 1(a). The points (a) to (c) for polishing pad A in Figure 2 correspond to the states (a) to (c) in Figure 1, respectively. In Figure 2, although there is no difference in step height between the dotted line and the solid line before polishing begins (point (a)), as polishing progresses and the amount of polishing reaches 2000 Å, it is shown that polishing pad A (dotted line) has a smaller step height than polishing pad B (solid line) (point (b)). Furthermore, as can be seen from Figure 2, the step height is reduced faster with polishing pad A (dotted line) than with polishing pad B (solid line) (point (c)). From the results in Figure 2, it can be said that polishing pad A, shown by the dotted line, has relatively higher step height reduction performance than polishing pad B, shown by the solid line.

[0020] (Defect) Furthermore, in this application, "defect" refers to a general term for defects including "particles," which are fine particles remaining on the surface of the workpiece; "pad debris," which are remnants of the polishing layer on the surface of the workpiece; and "scratches," which are scratches on the surface of the workpiece. Defect performance refers to the performance of reducing these "defects."

[0021] The following describes the polishing pad of this application, a method for manufacturing the polishing pad, and a method for polishing the surface of an optical material or semiconductor material.

[0022] 1. Polishing pad, method for manufacturing a polishing pad In some embodiments of the present application, the polishing pad has a polishing layer comprising a polyurethane resin, wherein the polyurethane resin is a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component. The curing agent includes an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the following formula (I): [ka] (In the above formula (I), R 1 It is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R 1 They may be the same or they may be different. n is between 2 and 30. m is between 0.1 and 20. By using a combination of an amine-based curing agent and a polyether polycarbonate diol curing agent represented by a specific structural formula, the resulting polishing pad exhibits excellent step-leveling performance, suppresses dishing, and reduces defects.

[0023] (Polishing pad) The polishing pad of this application has a polishing layer containing polyurethane resin. The polishing layer is positioned in direct contact with the material to be polished, and the rest of the polishing pad may be made of a material for supporting the polishing pad, such as an elastic material like rubber. Depending on the rigidity of the polishing pad, the polishing layer itself can function as the polishing pad.

[0024] The polishing pad of this invention does not differ significantly in shape from a general polishing pad, except that it can suppress dishing and defects in the workpiece, and can be used in the same way as a general polishing pad. For example, it can be used to polish by pressing the polishing layer against the workpiece while rotating the polishing pad, or by pressing the workpiece against the polishing layer while rotating the workpiece.

[0025] The polishing pad of this invention can be manufactured by generally known manufacturing methods such as mold molding and slab molding. First, a block of polyurethane is formed by these manufacturing methods, the block is made into a sheet by slicing or the like, an polishing layer formed from polyurethane resin is molded, and then it is bonded to a support or the like. Alternatively, the polishing layer can be molded directly onto the support.

[0026] More specifically, the polishing layer is fitted with double-sided tape on the side opposite to the polishing surface, cut to a predetermined shape, and becomes a polishing pad. There are no particular restrictions on the double-sided tape, and any double-sided tape known in the art can be arbitrarily selected and used. Furthermore, the polishing pad may be a single-layer structure consisting only of the polishing layer, or it may be a multi-layer structure in which other layers (underlayer, support layer) are attached to the side opposite to the polishing surface of the polishing layer.

[0027] The polished layer is formed by preparing a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and then curing the curable resin composition. The polishing layer can be made from foamed polyurethane resin, and foaming can be achieved by dispersing a foaming agent containing minute hollow spheres in the polyurethane resin. In this case, a curable resin composition containing an isocyanate-terminated urethane prepolymer, a curing agent, and a foaming agent can be prepared, and the polishing layer can be molded by foaming and curing the curable resin composition. The curable resin composition can also be a two-component composition prepared by mixing, for example, liquid A containing an isocyanate-terminated urethane prepolymer and liquid B containing a curing agent component. Other components may be added to either liquid A or liquid B, but if problems occur, the composition can be further divided into multiple liquids and mixed to form three or more liquids.

[0028] (Hardening agent) In some embodiments, the curing agent included in the curable resin composition includes an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the above formula (I).

[0029] In the above formula (I) representing the polyether polycarbonate diol, R 1 R is a divalent hydrocarbon group having 2 to 10 carbon atoms. 1Examples include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, 1,1-dimethylethylene, n-pentylene, 2,2-dimethylpropylene, 2-methylbutylene, or a combination of two or more of these. In particular, it is preferably at least one selected from the group consisting of ethylene, isopropylene, and n-butylene. In the above formula (I), a plurality of R 1 may be the same or different, but are preferably the same.

[0030] 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 0.1 to 20, preferably 0.5 to 10, and more preferably 1 to 5.

[0031] In some embodiments, the polyether polycarbonate diol curing agent represented by the above formula (I) preferably contains a structural unit derived from polytetramethylene ether glycol. By the polyether polycarbonate diol curing agent represented by the above formula (I) containing a structural unit derived from polytetramethylene ether glycol, the obtained polishing pad is excellent in flexibility at low temperatures. Further, the number average molecular weight of the structural unit derived from the polytetramethylene ether glycol is not particularly limited, but is preferably 100 to 1500, more preferably 150 to 1000, and most preferably 200 to 850.

[0032] When the polyether polycarbonate diol curing agent represented by the above formula (I) contains a structural unit derived from polytetramethylene ether glycol, the structural unit derived from the polytetramethylene ether glycol is preferably the part represented by -(R 1 -O) n - in the above formula (I).

[0033] The number-average molecular weight of the polyether polycarbonate diol curing agent represented by the above formula (I) is preferably 500 to 2500, more preferably 800 to 2500, and most preferably 1000 to 2000.

[0034] The number-average molecular weight of the polyether polycarbonate diol curing agent represented by formula (I) above and the structural units derived from the polytetramethylene ether glycol can be measured as the molecular weight in terms of polyethylene glycol / polyethylene oxide (PEG / PEO) based on gel permeation chromatography (GPC) under the following conditions. <Measurement conditions> Columns: Ohpak SB-802.5HQ (exclusion limit 10000) + SB-803HQ (exclusion limit 100000) Mobile phase: 5mM LiBr / DMF Flow rate: 0.3ml / min (26kg / cm 2 ) Oven: 60℃ Detector: RI 40℃ Sample volume: 20 μl

[0035] The amine-based curing agents used as curing agents include those described below. Examples of polyamines that constitute amine-based curing agents include diamines, which are 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 abbreviated as MOCA); hydroxyl group-containing diamines such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, especially hydroxyalkylalkylenediamines; or combinations of two or more of these. In addition, trifunctional triamine compounds and polyamine compounds with four or more functions can also be used.

[0036] A particularly preferred amine-based curing agent is MOCA, as described above, and its chemical structure is as follows.

[0037] [ka]

[0038] The total amount of curing agent used is such that the ratio of the total number of moles of NH2 from the amine-based curing agent and the number of moles of OH from the polyether polycarbonate diol curing agent represented by formula (I) above to the number of moles of NCO in the isocyanate-terminated urethane prepolymer ((moles of NH2 + moles of OH) / moles of NCO) is preferably 0.7 to 1.1, more preferably 0.75 to 1.0, and most preferably 0.8 to 0.95.

[0039] The weight ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent represented by formula (I) above, contained in the curing agent, is not particularly limited, but is preferably 8:2 to 2:8, more preferably 8:2 to 5:5, and most preferably 7:3 to 6:4. Furthermore, the molar ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent represented by formula (I) above, contained in the curing agent, is not particularly limited, but is preferably 9:1 to 5:5, and most preferably 8:2 to 6:4. By keeping the weight ratio or molar ratio of these curing agents within the above numerical range, the resulting polishing pad will have excellent step-eliminating performance, suppress dishing, and suppress defects.

[0040] (Isocyanate-terminated urethane prepolymer) In some embodiments, the isocyanate-terminated urethane prepolymer is a product obtained by reacting a polyol component with a polyisocyanate component.

[0041] The NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is preferably less than 600, more preferably between 350 and 550, and most preferably between 400 and 500. By having the NCO equivalent (g / eq) within the above numerical range, a polishing pad with appropriate polishing performance can be obtained.

[0042] (Polyol component) The polyol components contained in the isocyanate-terminated urethane prepolymer include low molecular weight polyols, high molecular weight polyols, or combinations thereof. In some embodiments, a low molecular weight polyol is a polyol with a number average molecular weight of 30 to 300, and a high molecular weight polyol is a polyol with a number average molecular weight greater than 300. The number average molecular weights of the low molecular weight polyol and the high molecular weight polyol can be measured by the same method as shown for the number average molecular weight of the polyether polycarbonate diol curing agent represented by formula (I) and the structural unit derived from the polytetramethylene ether glycol described above.

[0043] Examples of the low molecular weight polyols mentioned above 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, or combinations of two or more of these, with diethylene glycol being preferred among them.

[0044] The content of low molecular weight polyols relative to the entire isocyanate-terminated urethane prepolymer can be 0-20% by weight, 2-15% by weight, or 3-10% by weight. Alternatively, the content of low molecular weight polyols can be 0% by weight (no low molecular weight polyols). In this application, "no low molecular weight polyols" means that a certain component is not intentionally added, and does not exclude the presence of impurities.

[0045] The above high molecular weight polyols include polyether polyols such as polytetramethylene ether glycol (PTMG), polyethylene glycol, and polypropylene glycol; Polyester polyols such as reaction products of ethylene glycol and adipic acid, or reaction products of butylene glycol and adipic acid; The polyether polycarbonate diol represented by the above formula (I), as described in the above (curing agent) section; Polycarbonate polyol; Polycaprolactone polyol; Or a combination of two or more of these; In some embodiments, the high molecular weight polyol preferably includes a polyether polyol, and more preferably includes polytetramethylene ether glycol.

[0046] The content of high molecular weight polyol relative to the entire isocyanate-terminated urethane prepolymer is preferably 25 to 75% by weight, more preferably 35 to 65% by weight, and most preferably 40 to 60% by weight.

[0047] (Polyisocyanate component) The polyisocyanate components contained in isocyanate-terminated urethane prepolymers include: 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 (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'-Diphenylpropanediisocyanate, 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, Ethyridine diisothiocyanate, Alternatively, a combination of two or more of these may be given. Among these, it is preferable to use tolylene isocyanates such as 2,6-tolylene diisocyanate (2,6-TDI) and 2,4-tolylene diisocyanate (2,4-TDI) from the viewpoint of the polishing characteristics and mechanical strength of the resulting polishing pad.

[0048] The content of the polyisocyanate component relative to the entire isocyanate-terminated urethane prepolymer is preferably 20 to 50% by weight, more preferably 25 to 45% by weight, and most preferably 30 to 40% by weight.

[0049] (Microscopic hollow spheres) In some embodiments, the curable resin composition may further contain microscopic hollow spheres. A foam can be formed by mixing micro-hollow spheres with a polyurethane resin. Micro-hollow spheres refer to unfoamed, heat-expandable micro-spherical bodies consisting of an outer shell (polymer shell) made of thermoplastic resin and low-boiling point hydrocarbons enclosed within the outer shell, and unfoamed, heat-expandable micro-spherical bodies that have been heated and expanded. As the polymer shell, for example, thermoplastic resins such as acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, and vinyl chloride-ethylene copolymer can be used. Similarly, as the low-boiling point hydrocarbons enclosed within the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether, or a combination of two or more of these can be used.

[0050] (Other ingredients) Other catalysts commonly used in this industry may be added to the curable resin composition. Furthermore, the polyisocyanate component described above can also be added to the curable resin composition later. The weight ratio of the additional polyisocyanate component to the total weight of the isocyanate-terminated urethane prepolymer and the additional polyisocyanate component is preferably 0.1 to 10% by weight, more preferably 0.5 to 8% by weight, and particularly preferably 1 to 5% by weight. As the polyisocyanate component to be added to the polyurethane resin curable composition, any of the above-mentioned polyisocyanate components can be used without particular limitation, but 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI) is preferred.

[0051] 2. A method for polishing the surface of an optical material or semiconductor material. In this application, a method for polishing the surface of an optical material or semiconductor material includes the step of polishing the surface of the optical material or semiconductor material using the polishing pad described above. In some embodiments, a method for polishing the surface of an optical or semiconductor material may further include the step of supplying a slurry to the surface of a polishing pad, the surface of the optical or semiconductor material, or both.

[0052] (slurry) The liquid components in the slurry are not particularly limited, but include water (pure water), acids, alkalis, organic solvents, or combinations thereof, and are selected depending on the material of the object to be polished and the desired polishing conditions. Preferably, the slurry has water (pure water) as its main component, and preferably contains 80% by weight or more of water relative to the total slurry. The abrasive components in the slurry are not particularly limited, but include silica, zirconium silicate, cerium oxide, aluminum oxide, manganese oxide, or combinations thereof. The slurry may also contain other components such as organic substances soluble in the liquid components or pH adjusters. [Examples]

[0053] The present invention will be experimentally explained by the following examples, but the following explanation is not intended to be interpreted as limiting the scope of the present invention to these examples.

[0054] (material) The materials used in Examples 1 to 11 and Comparative Examples 1 to 3, described below, are listed below.

[0055] • Isocyanate-terminated urethane prepolymer: Prepolymer (1)...A urethane prepolymer with an NCO equivalent of 500, containing 412 parts by weight of 2,4-tolylene diisocyanate as a polyisocyanate component, 529 parts by weight of polytetramethylene ether glycol with a number average molecular weight of 650 as a high molecular weight polyol component, and 59 parts by weight of diethylene glycol as a low molecular weight polyol component. (The content of 2,4-tolylene diisocyanate, polytetramethylene ether glycol with a number average molecular weight of 650, and diethylene glycol in the total prepolymer (1) is 41.2% by weight, 52.9% by weight, and 5.9% by weight, respectively.)

[0056] • Hardener: MOCA···3,3'-Dichloro-4,4'-diaminodiphenylmethane (also known as methylenebis-o-chloroaniline) (MOCA) (NH2 equivalent = 133.5) PEPCD (Polyether Polycarbonate Diol) (1) ... A polyether polycarbonate diol containing structural units derived from polytetramethylene ether glycol with a number average molecular weight of 250, and having a number average molecular weight of 1000 (in formula (I) above, multiple R 1 Both are n-butylene, corresponding to a polyether polycarbonate diol with n = 3.2 and m = 2.8. Details are shown in Table 1 below. PEPCD(2)~(9)...each is a polyether polycarbonate diol (2)~(9) (Similar to PEPCD(1) above, details are shown in Table 1 below.) PTMG1000...Polytetramethylene ether glycol with a number-average molecular weight of 1000 PPG1000...Polypropylene glycol with a number-average molecular weight of 1000

[0057] [Table 1]

[0058] • Microscopic hollow spheres: Expancel461DU20 (manufactured by Nippon Filight Co., Ltd.)

[0059] (Example 1) 1000g of prepolymer (1) was prepared as component A, 169g of MOCA (a curing agent) and 270g of PEPCD (1) were prepared as component B, and 30g of micro hollow spheres (Expancel 461DU20) were prepared as component C. Although the proportions of each component are indicated in grams, the required weight (parts) should be prepared according to the size of the block. The following will also be expressed in grams (parts). Component A and component C were mixed, and the resulting mixture of component A and component C was degassed under reduced pressure. Component B, MOCA, and PEPCD(1) were also mixed, and the resulting mixture was degassed under reduced pressure. The degassed mixture of component A and component C and the degassed mixture of component B were fed into a mixer to obtain a mixture of component A, component B, and component C. The ratio of the total number of moles of NH2 in MOCA and OH in PEPCD to the number of moles of NCO in the obtained mixture of component A ((moles of NH2 + moles of OH) / moles of NCO) is 0.9. Furthermore, the molar ratio of MOCA to PEPCD in the obtained mixture of component A, component B, and component C is 7:3, and the weight ratio of MOCA to PEPCD is 3.8:6.2. The mixture of components A, B, and C was poured into a mold (850mm x 850mm square) heated to 80°C and primary cured at 80°C for 30 minutes. The formed resin foam was removed from the mold and secondary cured in an oven at 120°C for 4 hours. After the resulting resin foam was allowed to cool to 25°C, it was heated again in an oven at 120°C for 5 hours. The resulting resin foam was sliced ​​to a thickness of 1.3mm in the thickness direction to create a urethane sheet, and double-sided tape was attached to the back of this urethane sheet to create a polishing pad.

[0060] (Examples 2-6) Except for using 270g each of PEPCD(2) to (6) instead of 270g of PEPCD(1) in component B of Example 1, a urethane sheet was prepared in the same manner as in Example 1, and polishing pads for Examples 2 to 6 were obtained. Furthermore, in the resulting mixtures of components A, B, and C, the ratio of the total number of moles of NH2 from MOCA and OH from PEPCD ((moles of NH2 + moles of OH) / moles of NCO) to the number of moles of NCO from the prepolymer of component A is 0.9 in all cases. In addition, the molar ratio of MOCA to PEPCD in the resulting mixtures of components A, B, and C is 7:3 in all cases, and the weight ratio of MOCA to PEPCD is 3.8:6.2 in all cases.

[0061] (Examples 7-9) Except for using 535g each of PEPCD(7) to (9) instead of 270g of PEPCD(1) in component B of Example 1, a urethane sheet was prepared in the same manner as in Example 1, and polishing pads for Examples 7 to 9 were obtained. Furthermore, in the resulting mixtures of components A, B, and C, the ratio of the total number of moles of NH2 from MOCA and OH from PEPCD ((moles of NH2 + moles of OH) / moles of NCO) to the number of moles of NCO from the prepolymer of component A is 0.9 in all cases. In addition, the molar ratio of MOCA to PEPCD in the resulting mixtures of components A, B, and C is 7:3 in all cases, and the weight ratio of MOCA to PEPCD is 2.4:7.6 in all cases.

[0062] (Example 10) A urethane sheet was prepared in the same manner as in Example 1, except that 216 g of MOCA and 93 g of PEPCD(1) were used instead of 168 g of MOCA and 270 g of PEPCD(1) in component B of Example 1, to obtain the polishing pad of Example 10. Furthermore, in the resulting mixture of components A, B, and C, the ratio of the total number of moles of NH2 from MOCA and OH from PEPCD to the number of moles of NCO from the prepolymer of component A ((moles of NH2 + moles of OH) / moles of NCO) is 0.9. In addition, the molar ratio of MOCA to PEPCD in the resulting mixture of components A, B, and C is 9:1, and the weight ratio of MOCA to PEPCD is 7.0:3.0 in all cases.

[0063] (Example 11) A urethane sheet was prepared in the same manner as in Example 1, except that 120g of MOCA and 450g of PEPCD(1) were used instead of 168g of MOCA and 270g of PEPCD(1) in component B of Example 1, to obtain the polishing pad of Example 11. Furthermore, in the resulting mixture of components A, B, and C, the ratio of the total number of moles of NH2 from MOCA and OH from PEPCD to the number of moles of NCO from the prepolymer of component A ((moles of NH2 + moles of OH) / moles of NCO) is 0.9. In addition, the molar ratio of MOCA to PEPCD in the resulting mixture of components A, B, and C is 5:5, and the weight ratio of MOCA to PEPCD is 2.1:7.9 in all cases.

[0064] (Comparative Example 1) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 240g of MOCA was used instead of 168g of MOCA and 270g of PEPCD(1) in component B of Example 1. Furthermore, in the mixture of components A, B, and C, the ratio of moles of NH2 in MOCA (component B) to moles of NCO (component A) is 0.9.

[0065] (Comparative Example 2) A urethane sheet was prepared and an abrasive pad was obtained in the same manner as in Example 1, except that 270g of PTMG1000 was used instead of 270g of PEPCD(1) component B in Example 1. Furthermore, in the resulting mixture of components A, B, and C, the ratio of the total number of moles of NH2 from MOCA and OH from PEPCD in component B to the number of moles of NCO in the prepolymer of component A ((moles of NH2 + moles of OH) / moles of NCO) is 0.9. Also, in the resulting mixture of components A, B, and C, the molar ratio of MOCA to PTMG1000 is 7:3.

[0066] (Comparative Example 3) As Comparative Example 3, we prepared the IC1000 (manufactured by Nitta Haas), a conventionally known polishing pad.

[0067] (Evaluation method) For each of the polishing pads in Examples 1, 7, and 11, and Comparative Examples 1 to 3, the following evaluations were performed: (1) step-elimination performance and (2) defects.

[0068] (1) Performance in eliminating steps Each polishing pad was installed in a designated position on the polishing device using double-sided tape with acrylic adhesive, and polishing was performed under the conditions shown in <Polishing Conditions> below. After polishing, the step-leveling performance was evaluated by measuring with a micro-shape measuring device (KLA Tencor, P-16+OF). The evaluation results for each polishing pad are shown in Table 2 and Figures 3 and 4. <Measurement Procedure and Conditions> In this embodiment and comparative example, each pattern wafer (insulating film: Si(OC2H5)4 film) with a Cu film thickness of approximately 7000 Å and a step height of 3000-3300 Å, and having different wiring widths, was polished using each polishing pad, adjusting the polishing rate so that the amount of polishing per pass was approximately 1000 Å. Polishing was performed in stages, and the step height of the wafer was measured each time. The step height measurement was performed on each wiring width portion of the pattern wafer. The graph in Figure 3(a) shows the results when polishing a Cu wiring with a width of 120 μm and an insulating film width of 120 μm, Figure 3(b) shows the results when polishing a Cu wiring with a width of 100 μm and an insulating film width of 100 μm, Figure 4(c) shows the results when polishing a Cu wiring with a width of 50 μm and an insulating film width of 50 μm, and Figure 4(d) shows the results when polishing a Cu wiring with a width of 10 μm and an insulating film width of 10 μm. The smaller the wiring width value, the finer the wiring becomes.

[0069] <Polishing conditions> Polishing machine used: F-REX300X (manufactured by Ebara Corporation) Disk: A188 (manufactured by 3M) Abrasive temperature: 20℃ Polishing plate rotation speed: 90 rpm Polishing head rotation speed: 81 rpm Polishing pressure: 3.5 psi Polishing slurry: CSL-9044C (Use a mixture of CSL-9044C concentrate and pure water in a weight ratio of 1:9) (Manufactured by Fujifilm Planar Solutions) Polishing slurry flow rate: 200 ml / min Polishing time: 60 seconds Workpiece to be polished: (Step reduction performance) Each of the pattern wafers mentioned above, (Defect) Cu film substrate Pad Break: 32N 10 minutes Conditioning: in-situ 18N 16 scans, ex-situ 35N 4 scans

[0070] (2) Defect Each polishing pad was placed in a predetermined position on the polishing apparatus using double-sided tape with an acrylic adhesive, and the Cu film substrate (a 12-inch diameter disc) was polished under the conditions described in (1) Polishing Conditions for Step Elimination Performance above. Cu film substrates that had undergone polishing treatment for the 16th, 26th, and 51st time were measured using a surface inspection device (KLA-Tencor, Surfscan SP2XP) in high-sensitivity measurement mode. The number of micro-scratches (fine dent-like scratches between 0.2 μm and 10 μm) on the entire substrate surface was observed and the total was calculated. The evaluation results are shown in Table 3 and Figure 5. A defect rate of 5 or fewer micro-scratches indicates a good performance.

[0071] [Table 2]

[0072] *(a) to (d) in Table 2 indicate the following: (a): Polishing of the Cu wiring area on the patterned wafer with a width of 120 μm and the insulating film width of 120 μm. (b): Polishing of the Cu wiring area on the pattern wafer with a width of 100 μm and the insulating film width of 100 μm. (c): Polishing of the Cu wiring area on the pattern wafer with a width of 50 μm and the insulating film with a width of 50 μm. (d): Polishing of the Cu wiring area on the patterned wafer with a width of 10 μm and an insulating film width of 10 μm.

[0073] [Table 3]

[0074] Examples 1 to 11 relate to polishing pads formed using a curing agent containing an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the above formula (I). Comparative Example 1 relates to a polishing pad formed using a curing agent containing only an amine-based curing agent. Comparative Example 2 relates to a polishing pad formed using a curing agent containing an amine-based curing agent and a polytetramethylene ether glycol curing agent. Comparative Example 3 relates to a conventionally known polishing pad.

[0075] Regarding the results of the step-elimination performance described in (1) above (Evaluation Method), the polishing pads of Examples 1, 7, and 11 all exhibited superior step-elimination performance compared to the polishing pads of Comparative Examples 1 to 3, at all wiring widths of 120 μm, 100 μm, 50 μm, and 10 μm. Furthermore, regarding the results of the defect performance described in (2) above (Evaluation Method), the polishing pads of Examples 1, 7, and 11 all had 5 or fewer micro-scratches, while the polishing pads of Comparative Examples 1 to 3 had more than 5 micro-scratches. Therefore, it was found that the pads of the examples exhibited superior step-elimination performance and could suppress the occurrence of defects.

[0076] Based on the above, polishing pads formed using a curing agent containing an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the above formula (I) can suppress dishing during polishing (excellent step-leveling performance) and can also suppress the occurrence of defects.

Claims

1. A polishing pad having an abrasive layer containing polyurethane resin, The polyurethane resin is a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent, and the isocyanate-terminated urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component. The curing agent comprises an amine-based curing agent and a polyether polycarbonate diol curing agent represented by the following formula (I), the polishing pad: 【Chemistry 1】 (In the above formula (I), R １ is a divalent hydrocarbon group having 2 to 10 carbon atoms, and multiple R １ They may be the same or they may be different. n is between 2 and 30. m is between 0.1 and 20.

2. The polishing pad according to claim 1, wherein the polyether polycarbonate diol curing agent contains structural units derived from polytetramethylene ether glycol.

3. The polishing pad according to claim 1 or 2, wherein the weight ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent is 8:2 to 2:

8.

4. The polishing pad according to claim 1 or 2, wherein the molar ratio of the amine-based curing agent to the polyether polycarbonate diol curing agent is 9:1 to 5:

5.

5. R in formula (I) １ The polishing pad according to claim 1 or 2, wherein the material is at least one selected from the group consisting of ethylene, isopropylene, and n-butylene.

6. The polishing pad according to claim 1 or 2, wherein the number average molecular weight of the polyether polycarbonate diol curing agent is 500 to 2500.

7. The polishing pad according to claim 1 or 2, wherein the amine-based curing agent comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.

8. The polishing pad according to claim 1 or 2, wherein the polyisocyanate component comprises tolylene diisocyanate.

9. The polishing pad according to claim 1 or 2, further comprising the curable resin composition with micro hollow spheres.

10. A method for manufacturing an abrasive pad according to claim 1 or 2, comprising the step of forming the abrasive layer.

11. A method for polishing the surface of an optical material or a semiconductor material, comprising the step of polishing the surface of the optical material or a semiconductor material using a polishing pad according to claim 1 or 2.

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