Polishing pad and manufacturing method for polished work-piece

Abstract

To provide a polishing pad that can reduce occurrence of scratches and a manufacturing method for a polished work-piece.SOLUTION: The polishing pad comprises a polyurethane sheet as a polishing layer. In dynamic viscoelasticity measurement that is performed in a submerged state under the condition that a frequency is 1.6 Hz and a temperature is in a range of 20-100°C, the polyurethane sheet has a peak of loss tangent tanδ in a range of 40-60°C.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a polishing pad and a polished workpiece. [Background technology]

[0002] The surfaces (machined surfaces) of materials such as semiconductor devices and electronic components, particularly thin substrates (workpieces) such as Si substrates (silicon wafers), hard disk substrates, glass, and LCD (liquid crystal display) substrates, are chemically mechanically polished using a polishing pad and a polishing slurry.

[0003] As polishing pads used in such polishing processes, for example, polishing pads having a polishing layer with an E' ratio at 30°C to 90°C of about 1 to 3.6 for the purpose of reducing dishing (Patent Document 1), and polishing pads having a polishing layer made of a polymer material with a porosity of 0.1 volume %, a KEL energy loss coefficient of 385 to 750 l / Pa at 40°C and 1 rad / sec, and an elastic modulus E' of 100 to 400 MPa at 40°C and 1 rad / sec for the purpose of achieving both planarization performance and low defect performance rate are known to be used (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2004-507076 [Patent Document 2] JP 2005-136400 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has been found that when the polishing pads described in the above Patent Documents 1 and 2 are used, the surface quality of the polished object obtained cannot be said to be high, and for example, scratches and the like occur.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a polishing pad and a method for manufacturing a polished product that can reduce the occurrence of scratches. [Means for solving the problem]

[0007] As a result of intensive research into solving the above problems, the inventors discovered that the above problems can be solved by using as a polishing layer a polyurethane sheet that, when subjected to dynamic viscoelasticity measurement under submerged (underwater) conditions, produces a peak tan δ within a specific temperature range, and thus completed the present invention.

[0008] That is, the present invention is as follows. [1] A polyurethane sheet is provided as the polishing layer, In a dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and a temperature range of 20 to 100°C while immersed in water, the polyurethane sheet has a peak of loss tangent tanδ in the range of 40 to 60°C. Polishing pad. [2] the peak value of the loss tangent tanδ is 0.15 to 0.35; The polishing pad described in [1]. [3] In a dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and a temperature range of 20 to 100°C while immersed in water, the loss modulus E'' of the polyurethane sheet at 40°C is 21 MPa or more. The polishing pad according to [1] or [2]. [4] In a dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and a temperature range of 20 to 100°C while submerged in water, the difference A in the loss tangent tanδ of the polyurethane sheet at 60°C and 70°C is smaller than the difference B in the loss tangent tanδ at 50°C and 60°C, and the difference C in the loss tangent tanδ at 70°C and 80°C. The polishing pad according to any one of [1] to [3]. [5] The polyurethane sheet contains a polyurethane resin and hollow fine particles dispersed in the polyurethane resin. The polishing pad according to any one of [1] to [4]. [6] A polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [5] in the presence of a polishing slurry. A method for manufacturing polished workpieces. Effect of the Invention

[0009] According to the present invention, it is possible to provide a polishing pad and a method for manufacturing a polished product that can reduce the occurrence of scratches. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing the results of dynamic viscoelasticity measurement in Example 1. [Diagram 2] FIG. 13 is a diagram showing the results of dynamic viscoelasticity measurement in Example 2. [Diagram 3] FIG. 1 is a diagram showing the results of dynamic viscoelasticity measurement in Comparative Example 1. [Figure 4] FIG. 13 is a diagram showing the results of dynamic viscoelasticity measurement in Comparative Example 2. [Diagram 5] FIG. 13 is a diagram showing the results of dynamic viscoelasticity measurement in Comparative Example 3. [Figure 6] FIG. 13 is a diagram showing the results of dynamic viscoelasticity measurement in Comparative Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Below, we will explain in detail the embodiment of the present invention (hereinafter referred to as the "present embodiment"). However, the present invention is not limited to this embodiment, and various modifications are possible without departing from the gist of the present invention.

[0012] [Polishing pad] The polishing pad of this embodiment has a polyurethane sheet as a polishing layer, and in dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and a temperature range of 20 to 100°C while immersed in water, the polyurethane sheet has a peak of loss tangent tan δ in the range of 40 to 60°C.

[0013] (loss tangent tanδ) The loss tangent tan δ is a value expressed by the ratio of the loss modulus E″ (viscous component) to the storage modulus E′ (elastic component), and is an index showing the balance between the elasticity and viscosity of the substance to be measured under the measurement conditions. It is known that the loss tangent tan δ differs depending on whether the substance to be measured is in a dry state or a water-soaked state, and also differs depending on the frequency at the time of measurement. In this embodiment, the dynamic viscoelasticity of the polishing layer in the dynamic process during polishing is controlled within a predetermined range, thereby improving the contact state with the object to be polished (workpiece) during polishing, and further suppressing the persistent pressing of polishing waste generated by polishing, thereby suppressing the occurrence of scratches. More specifically, the occurrence of scratches can be suppressed by creating a state in which the loss modulus E″ (viscous component) is more dominant than the storage modulus E′ (elastic component) under the polishing conditions.

[0014] Under polishing conditions, the polishing layer is wetted with the slurry and comes into contact with the workpiece by a predetermined polishing operation at a predetermined temperature. Therefore, in this embodiment, it is specified that the polishing layer has a peak of loss tangent tan δ in a temperature range (40 to 60° C.) equivalent to the temperature in the polishing process in a dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and 20 to 100° C. while submerged in water.

[0015] The peak temperature of the loss tangent tan δ is 40 to 60° C., preferably 40 to 56° C., and more preferably 40 to 52° C. When the peak of the loss tangent tan δ is within the above temperature range, a state occurs in which the loss modulus E″ (viscous component) is more dominant than the storage modulus E′ (elastic component) in the same temperature range as the temperature of the polishing step, and the occurrence of scratches is suppressed.

[0016] Here, "having a peak of loss tangent tanδ in the range of 40 to 60° C. in dynamic viscoelasticity measurement performed under the condition of 20 to 100° C." means that the maximum value of loss tangent tanδ in the range of 20 to 100° C. is in the range of 40 to 60° C. In addition, in this embodiment, "peak" refers to a difference between the maximum value and the minimum value of 0.05 or more in a temperature range of ±5° C. at the temperature where the maximum value is reached, and any smaller fluctuations up and down due to noise or the like are not interpreted as a peak.

[0017] The peak value of the loss tangent tanδ is preferably 0.15 to 0.35, more preferably 0.20 to 0.35, and further preferably 0.22 to 0.35. When the peak value of the loss tangent tanδ is within the above range, a state in which the loss modulus E'' (viscous component) is more dominant over the storage modulus E' (elastic component) in the same temperature range as the temperature of the polishing step is more effectively realized, and the occurrence of scratches tends to be more suppressed.

[0018] In dynamic viscoelasticity measurement performed under conditions of immersion in water, frequency of 1.6 Hz, and temperature of 20 to 100°C, the loss modulus E'' of the polyurethane sheet at 40°C is preferably 21 MPa or more, more preferably 22 to 45 MPa, and even more preferably 23 to 40 MPa. When the loss modulus E'' at 40°C is within the above range, a state in which the loss modulus E'' (viscous component) is more dominant over the storage modulus E' (elastic component) in the same temperature range as the temperature of the polishing step is more effectively realized, and the occurrence of scratches tends to be further suppressed.

[0019] Furthermore, in a dynamic viscoelasticity measurement performed under conditions of immersion, frequency 1.6 Hz, and 20 to 100°C, it is preferable that the difference A in the loss tangent tanδ of the polyurethane sheet at 60°C and 70°C is smaller than the difference B in the loss tangent tanδ at 50°C and 60°C, and the difference C in the loss tangent tanδ at 70°C and 80°C. That is, as shown in FIG. 1 described later, it is preferable that the chart of the loss tangent tanδ has a shoulder on the high temperature side of the peak. By having a shoulder on the high temperature side in this way, a relatively high tanδ (in water) is maintained even on the high temperature side of the peak. Therefore, it is possible to realize a state in which the loss modulus E'' (viscous component) is more dominant than the storage modulus E' (elastic component) in a wider temperature range. As a result, even if a part with a high temperature occurs locally due to frictional heat or the like in the polishing process, it is possible to suppress the storage modulus E' (elastic component) from becoming dominant in that part, and the occurrence of scratches tends to be further suppressed.

[0020] The difference A between the loss tangent tan δ of the polyurethane sheet at 60° C. and 70° C. is preferably 0.010 to 0.035, more preferably 0.010 to 0.030, and even more preferably 0.012 to 0.028. The difference B between the loss tangent tan δ of the polyurethane sheet at 50° C. and 60° C. is preferably 0.035 to 0.060, more preferably 0.038 to 0.050, and even more preferably 0.040 to 0.045. The difference C between the loss tangent tan δ of the polyurethane sheet at 70° C. and 80° C. is preferably 0.055 to 0.095, more preferably 0.060 to 0.090, and even more preferably 0.065 to 0.085.

[0021] The difference between the difference A indicating the slope of the loss tangent tan δ at 60° C. and 70° C. and the difference B indicating the slope of the loss tangent tan δ at 50° C. and 60° C. is preferably 0.010 to 0.040, more preferably 0.014 to 0.035, and even more preferably 0.016 to 0.030. The difference between the difference A indicating the slope of the loss tangent tan δ at 60° C. and 70° C. and the difference C indicating the slope of the loss tangent tan δ at 70° C. and 80° C. is preferably 0.030 to 0.080, more preferably 0.040 to 0.070, and even more preferably 0.050 to 0.060.

[0022] The dynamic viscoelasticity measurement of this embodiment can be carried out according to a conventional method, but in the dynamic viscoelasticity measurement in a water-immersed state, a polishing layer immersed in water at a temperature of 23°C for 3 days is used as a sample, and the sample is measured in a water-immersed state. An example of a dynamic viscoelasticity measuring device capable of such measurement is DMA8000 manufactured by PerkinElmer Japan Co., Ltd. Other conditions are not particularly limited, but can be measured under the conditions described in the examples.

[0023] (Polyurethane sheet) As the polishing layer having the above characteristics, a polyurethane sheet is used. The polyurethane resin constituting the polyurethane sheet is not particularly limited, but for example, polyester polyurethane resin, polyether polyurethane resin, and polycarbonate polyurethane resin can be mentioned. These may be used alone or in combination of two or more.

[0024] Such polyurethane resin is not particularly limited as long as it is a reaction product of a urethane prepolymer and a curing agent, and various known ones can be applied. Here, the urethane prepolymer is not particularly limited, but examples thereof include an adduct of hexamethylene diisocyanate and hexanetriol; an adduct of 2,4-tolylene diisocyanate and prenzcatechol; an adduct of tolylene diisocyanate and hexanetriol; an adduct of tolylene diisocyanate and trimethylolpropane; an adduct of xylylene diisocyanate and trimethylolpropane; an adduct of hexamethylene diisocyanate and trimethylolpropane; and an adduct of isocyanuric acid and hexamethylene diisocyanate. In addition, an isocyanate group-containing compound prepared by the reaction of a polyisocyanate compound and a polyol compound, or various commercially available urethane prepolymers may be used. The urethane prepolymer may be used alone or in combination of two or more types.

[0025] The polyisocyanate compound used in the isocyanate group-containing compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, diisocyanate compounds having two isocyanate groups in the molecule include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl- Examples of the diisocyanate include diphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, and ethylidine diisothiocyanate. As the polyisocyanate compound, a diisocyanate compound is preferable, and among them, 2,4-TDI, 2,6-TDI and MDI are more preferable, and 2,4-TDI and 2,6-TDI are particularly preferable. These polyisocyanate compounds may be used alone, or a plurality of polyisocyanate compounds may be used in combination.

[0026] The polyisocyanate compound preferably contains 2,4-TDI and / or 2,6-TDI, more preferably contains 2,4-TDI and 2,6-TDI, and even more preferably consists of 2,4-TDI and 2,6-TDI. The mass ratio of 2,4-TDI to 2,6-TDI is preferably 100:0 to 50:50, more preferably 90:10 to 60:40, even more preferably 90:10 to 70:30, and even more preferably 80:20.

[0027] Examples of the polyol compound used in the isocyanate group-containing compound include diol compounds, triol compounds, etc., such as ethylene glycol, diethylene glycol (DEG), butylene glycol, etc.; polyether polyol compounds, such as polypropylene glycol (PPG) and poly(oxytetramethylene) glycol (PTMG); polyester polyol compounds, such as a reaction product of ethylene glycol and adipic acid, or a reaction product of butylene glycol and adipic acid; polycarbonate polyol compounds, polycaprolactone polyol compounds, etc. Also, trifunctional propylene glycol to which ethylene oxide is added can be used. Among these, PTMG is preferred, and it is also preferred to use PTMG and DEG in combination. The number average molecular weight (Mn) of PTMG is preferably 500 to 2000, more preferably 500 to 1300, even more preferably 500 to 1000, and even more preferably 500 to 800. The number average molecular weight can be measured by gel permeation chromatography (GPC). In addition, when measuring the number average molecular weight of a polyol compound from a polyurethane resin, it can be estimated by GPC after decomposing each component by a conventional method such as amine decomposition. A polyol compound may be used alone, or a plurality of polyol compounds may be used in combination.

[0028] The NCO equivalent of the urethane prepolymer is preferably 300 to 700, more preferably 350 to 600, and further preferably 400 to 500. The "NCO equivalent" is calculated by "(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)]" and is a numerical value indicating the molecular weight of the urethane prepolymer per NCO group.

[0029] The curing agent is not particularly limited, but examples thereof include ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4-methyl-2,6-bis(methylthio)-1,3-benzenediamine, 2-methyl-4,6-bis(methylthio)-1,3-benzenediamine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis[3-(isopropyl)phenyl] ... polyamine compounds such as 2,2-bis[3-(1-methylpropylamino)-4-hydroxyphenyl]propane, 2,2-bis[3-(1-methylpentylamino)-4-hydroxyphenyl]propane, 2,2-bis[3-(1-methylpentylamino)-4-hydroxyphenyl]propane, 2,2-bis(3,5-diamino-4-hydroxyphenyl)propane, 2,6-diamino-4-methylphenol, trimethylethylene bis-4-aminobenzoate, and polytetramethylene oxide-di-p-aminobenzoate; ethylene glycol Coal, 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 glycol, 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, poly(oxytetramethylene) glycol, polyethylene glycol, and polypropylene glycol.Furthermore, the polyvalent amine compound may have a hydroxyl group, and examples of such amine compounds include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine.

[0030] As the polyvalent amine compound, a diamine compound is preferable, and 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) is particularly preferable. Examples of MOCA include PANDEX E (manufactured by DIC Corporation) and Iharakyuamine MT (manufactured by Kumiai Chemical Co., Ltd.). As the polyhydric alcohol compound, polypropylene glycol is preferable, polypropylene glycol having a number average molecular weight of 1000 to 3000 is more preferable, and polypropylene glycol having a number average molecular weight of 1500 to 2500 is even more preferable. The curing agent may be used alone or in combination of two or more kinds.

[0031] The curing agent is added in an amount of preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, per 100 parts by mass of the urethane prepolymer.

[0032] The peak temperature of the loss tangent tanδ can be adjusted by the molecular weight (degree of polymerization) of the urethane prepolymer and the combination of the urethane prepolymer and the curing agent. From this viewpoint, for example, it is preferable to mix each component so that the R value, which is the equivalent ratio of the active hydrogen groups (amino groups and hydroxyl groups) present in the curing agent to the isocyanate groups present at the terminals of the isocyanate group-containing compound as the urethane prepolymer, is 0.70 to 1.30, more preferably 0.75 to 1.20, even more preferably 0.80 to 1.10, still more preferably 0.80 to 1.00, and even more preferably 0.85 to 0.95.

[0033] The polyurethane sheet is preferably a foamed polyurethane sheet having bubbles. The bubbles of the foamed polyurethane sheet are classified into closed bubbles, in which a plurality of bubbles exist independently, and open bubbles, in which a plurality of bubbles are connected by communicating holes, depending on the form of the bubbles. Among these, the polyurethane sheet of the present embodiment preferably has closed bubbles, and is more preferably a polyurethane sheet containing a polyurethane resin and hollow fine particles dispersed in the polyurethane resin. The use of hollow fine particles tends to facilitate the adjustment of the peak temperature of the loss tangent tanδ.

[0034] The polyurethane sheet having closed cells can be formed by using hollow particles having an outer shell and a hollow inside. The hollow particles may be commercially available or may be obtained by synthesis by a conventional method. The material of the outer shell of the hollow particles is not particularly limited, and examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, poly(meth)acrylic acid, polyacrylamide, polyethylene glycol, polyhydroxyether acrylate, maleic acid copolymer, polyethylene oxide, polyurethane, poly(meth)acrylonitrile, polyvinylidene chloride, polyvinyl chloride and organic silicone resins, and copolymers of two or more monomers constituting these resins. In addition, examples of commercially available hollow particles include, but are not limited to, Expancel series (trade name manufactured by Akzo Nobel), Matsumoto Microsphere (trade name manufactured by Matsumoto Yushi Co., Ltd.), and the like.

[0035] The shape of the hollow fine particles in the polyurethane sheet is not particularly limited, and may be, for example, spherical or nearly spherical. The average particle size of the hollow fine particles is not particularly limited, but is preferably 5 to 200 μm, more preferably 5 to 80 μm, further preferably 5 to 50 μm, and particularly preferably 5 to 35 μm. The peak temperature of the loss tangent tan δ can also be adjusted by using such hollow fine particles. The average particle size can be measured by a laser diffraction particle size distribution measuring device (for example, Mastersizer 2000, manufactured by Spectris Co., Ltd.).

[0036] The hollow fine particles are added in an amount of preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, and even more preferably 1 to 3 parts by mass, based on 100 parts by mass of the urethane prepolymer.

[0037] In addition to the above components, conventionally used blowing agents may be used in combination with the hollow microparticles within the range that does not impair the effects of the present invention, and a gas that is non-reactive with each of the above components may be blown in during the mixing step described below. Examples of the blowing agent include water and blowing agents that are mainly composed of a hydrocarbon having 5 or 6 carbon atoms. Examples of the hydrocarbon include chain hydrocarbons such as n-pentane and n-hexane, and alicyclic hydrocarbons such as cyclopentane and cyclohexane. In addition to the above components, known foam stabilizers, flame retardants, colorants, plasticizers, etc. may be added.

[0038] The method for producing the polyurethane sheet is not particularly limited, but for example, a method of reacting a urethane prepolymer with a curing agent to form a polyurethane resin block, and cutting out a sheet from the obtained polyurethane resin block can be mentioned. In the mixing step, the urethane prepolymer and the curing agent are fed into a mixer and stirred and mixed. In addition, when hollow fine particles are used, a polyurethane resin block incorporating hollow fine particles can be obtained by mixing the urethane prepolymer, the curing agent, and the hollow fine particles. There is no particular limit to the order of mixing, but it is preferable to mix the urethane prepolymer and the hollow fine particles first, and then feed the curing agent into the mixer. In this way, a mixed solution for the polyurethane resin block is prepared. The mixing step is carried out in a state where the mixture is heated to a temperature at which the fluidity of each of the above components can be ensured.

[0039] For example, a solution of a urethane prepolymer (e.g., an isocyanate group-containing compound) containing hollow fine particles is heated to 30 to 90°C, and a curing agent is added to a temperature-controllable jacketed mixer, and the mixture is stirred at 30 to 130°C. If necessary, the mixture may be transferred to a jacketed tank equipped with a stirrer and aged. The stirring time is adjusted appropriately depending on the number of teeth, rotation speed, clearance, etc. of the mixer, and is, for example, 0.1 to 60 seconds.

[0040] In the molding step, the polyurethane resin block mixture prepared in the mixing step is poured into a mold preheated to 30 to 100°C, and heated at about 100 to 150°C for about 10 minutes to 5 hours to harden the mixture into a polyurethane resin block. At this time, the urethane prepolymer reacts with the hardener to form a polyurethane resin, and the mixture hardens in a state in which air bubbles and / or hollow particles are dispersed in the polyurethane resin. This results in the formation of a polyurethane resin block containing a large number of roughly spherical air bubbles.

[0041] The polyurethane resin block obtained by the molding step is then sliced ​​into sheets to form polyurethane sheets. By slicing, openings are provided on the surface of the sheet. At this time, in order to form openings on the surface of the polishing layer that is highly resistant to wear and less prone to clogging, the sheet may be aged at 30 to 150°C for about 1 to 24 hours.

[0042] The polishing layer having the polyurethane sheet thus obtained is then attached with a double-sided tape on the surface opposite to the polishing surface of the polishing layer, and cut into a predetermined shape, preferably a disk shape, to complete the polishing pad of this embodiment. There is no particular restriction on the double-sided tape, and any double-sided tape known in the art can be selected and used.

[0043] In addition, the polishing pad of this embodiment may be a single-layer structure consisting of only the polishing layer, or may be a multi-layer structure in which another layer (lower layer, support layer) is attached to the surface opposite to the polishing surface of the polishing layer. The properties of the other layer are not particularly limited, and if a layer softer than the polishing layer (lower A hardness or D hardness) is attached to the surface opposite to the polishing layer, the polishing flatness is further improved. On the other hand, if a layer harder than the polishing layer (higher A hardness or D hardness) is attached to the surface opposite to the polishing layer, the polishing rate is further improved.

[0044] In the case of a multi-layer structure, the layers may be bonded and fixed together, if necessary, under pressure, using double-sided tape, adhesive, etc. There are no particular limitations on the double-sided tape or adhesive used in this case, and any double-sided tape or adhesive known in the art may be selected and used.

[0045] Furthermore, in the polishing pad of this embodiment, if necessary, the surface and / or back surface of the polishing layer may be subjected to grinding, groove processing, embossing, or hole processing (punching) on ​​the surface, the substrate and / or adhesive layer may be attached to the polishing layer, and a light transmitting portion may be provided. There is no particular limitation on the method of grinding, and grinding can be performed by a known method. Specifically, grinding with sandpaper can be mentioned. There is no particular limitation on the shape of the groove processing and embossing, and examples thereof include a lattice type, a concentric circle type, and a radial type.

[0046] [Method for manufacturing polished product] The method for producing the polished product of this embodiment includes a polishing step of polishing a workpiece using the polishing pad in the presence of a polishing slurry to obtain a polished product. The polishing step may be primary polishing (rough polishing), finish polishing, or a combination of both. Among these, the polishing pad of this embodiment is preferably used for chemical mechanical polishing. Hereinafter, the method for producing the polished product of this embodiment will be described using chemical mechanical polishing as an example, but the method for producing the polished product of this embodiment is not limited to the following.

[0047] In this manufacturing method, the polishing slurry is supplied, and the holding platen and the polishing platen are rotated relative to each other while the object to be polished is pressed against the polishing pad by the holding platen, so that the processed surface of the object to be polished is polished by the polishing pad by chemical mechanical polishing (CMP). The holding platen and the polishing platen may rotate in the same direction at different rotation speeds, or in different directions. The object to be polished may be polished while moving (rotating) inside the frame during the polishing process.

[0048] The polishing slurry may contain water, chemical components such as an oxidizing agent such as hydrogen peroxide, additives, abrasive grains (polishing particles; e.g., SiC, SiO2, Al2O3, CeO2), etc. depending on the object to be polished and the polishing conditions.

[0049] The object to be polished is not particularly limited, but examples thereof include materials such as semiconductor devices and electronic components, particularly thin substrates (objects to be polished) such as Si substrates (silicon wafers), substrates for hard disks, glass and substrates for LCDs (liquid crystal displays). Among these, the method for manufacturing the polished object of the present embodiment can be suitably used as a method for manufacturing semiconductor devices having an oxide layer, a metal layer such as copper, etc. EXAMPLES

[0050] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0051] Example 1 2,4-tolylene diisocyanate (TDI), poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 650, and diethylene glycol (DEG) were reacted to form 100 parts of a urethane prepolymer with an NCO equivalent of 460. The shell portion was made of an acrylonitrile-vinylidene chloride copolymer, and 2.8 parts of expanded hollow fine particles with a particle size of 15 to 25 μm (average particle size: 20 μm) in which isobutane gas was encapsulated in the shell were added and mixed to obtain a urethane prepolymer mixed liquid. The obtained urethane prepolymer mixed liquid was charged into a first liquid tank and kept at 80°C. In addition to the first liquid tank, 25.5 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylenebis-o-chloroaniline) (MOCA) and 8.5 parts of polypropylene glycol were charged into a second liquid tank as a curing agent, and the curing agent was heated and melted at 120°C and mixed, and further degassed under reduced pressure to obtain a curing agent melt liquid.

[0052] Next, the liquids in the first liquid tank and the second liquid tank were poured into a mixer equipped with two injection ports, and mixed and stirred to obtain a mixed liquid. At this time, the mixing ratio was adjusted so that the R value, which represents the equivalent ratio of the amino group and hydroxyl group in the curing agent to the isocyanate group at the end of the urethane prepolymer, was 0.90.

[0053] The resulting mixture was poured into a mold preheated to 100°C and cured primarily at 110°C for 30 minutes. The resulting block-shaped molding was removed from the mold and cured secondary at 130°C for 2 hours in an oven to obtain a urethane resin block. The resulting urethane resin block was allowed to cool to 25°C, and then heated again in an oven at 120°C for 5 hours, after which it was sliced ​​to obtain a foamed polyurethane sheet. Double-sided tape was attached to the back of the resulting polyurethane sheet, and it was used as a polishing pad.

[0054] Example 2 100 parts of the same urethane prepolymer as in Example 1 were mixed with 3.1 parts of unexpanded hollow fine particles with a particle size of 5 to 15 μm (average particle size: 7 μm) in which isobutane gas was encapsulated in the shell, and 2 parts of 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI) to obtain a urethane prepolymer mixture. 28 parts of MOCA were heated and melted as a curing agent, and mixed to obtain a curing agent melt. A polishing pad was produced in the same manner as in Example 1 using the urethane prepolymer mixture and the curing agent melt.

[0055] Comparative Example 1 As Comparative Example 1, an IC1000 pad manufactured by Nitta Haas was prepared.

[0056] Comparative Example 2 2,4-tolylene diisocyanate (TDI), poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 650, poly(oxytetramethylene) glycol (PTMG) with a number average molecular weight of 1000, and diethylene glycol (DEG) were reacted to obtain 100 parts of a urethane prepolymer with an NCO equivalent of 460. The shell part was made of an acrylonitrile-vinylidene chloride copolymer, and 2.1 parts of expanded hollow fine particles with a particle size of 30 to 50 μm (average particle size: 40 μm) in which isobutane gas was encapsulated in the shell were added and mixed to obtain a urethane prepolymer mixture. 27 parts of MOCA and 8.7 parts of polypropylene glycol were heated and melted as a curing agent, and mixed, and further degassed under reduced pressure to obtain a curing agent melt. A polishing pad was obtained by producing the polishing pad using the urethane prepolymer mixture and the curing agent melt in the same manner as in Example 1.

[0057] Comparative Example 3 100 parts of the urethane prepolymer of Comparative Example 2 was mixed with 3.0 parts of hollow fine particles similar to those used in Example 1 to obtain a urethane prepolymer mixed solution. 25.8 parts of MOCA and 8.6 parts of polypropylene glycol were heated and melted as a curing agent, and then degassed under reduced pressure to obtain a curing agent melt solution. Using the urethane prepolymer mixed solution and the curing agent melt solution, a polishing pad was obtained by the same method as in Example 1.

[0058] Comparative Example 4 100 parts of the urethane prepolymer of Comparative Example 2 was mixed with 3.0 parts of hollow fine particles similar to those used in Example 2 to obtain a urethane prepolymer mixed solution. 25.8 parts of MOCA and 8.6 parts of polypropylene glycol were heated and melted as a curing agent, and then degassed under reduced pressure to obtain a curing agent melt solution. Using the urethane prepolymer mixed solution and the curing agent melt solution, a polishing pad was obtained by the same method as in Example 1.

[0059] [Dynamic viscoelasticity measurement] Dynamic viscoelasticity measurements were performed on the polyurethane sheet under the following conditions. First, the polyurethane sheet was immersed in water at 23°C for 3 days. The resulting polyurethane sheet was used as a sample and dynamic viscoelasticity measurements were performed in water (submerged state). A DMA8000 (PerkinElmer Japan) was used as the dynamic viscoelasticity measuring device. (Measurement conditions) Measuring device: DMA8000 (PerkinElmer Japan) Sample: Length 4cm x Width 0.5cm x Thickness 0.125cm Test length: 1cm Sample pretreatment: Keep in water at 23°C for 3 days Test mode: Tensile Frequency: 1.6Hz (10rad / sec) Temperature range: 20~100℃ Heating rate: 5℃ / min Distortion range: 0.10% Initial load: 148g Measurement interval: 1point / ℃

[0060] For reference, a polyurethane sheet in a dry state was kept in a thermo-hygrostat at a temperature of 23°C (±2°C) and a relative humidity of 50% (±5%) for 40 hours, and a dynamic viscoelasticity measurement was performed in normal air (dry state) using the polyurethane sheet as a sample. The measurement was performed under the same conditions as above, except that an RSA3 (manufactured by TA Instruments) was used as the device. The results of the dynamic viscoelasticity measurement of the examples and comparative examples are shown in Figures 1 to 3. In the figures, the results marked "(in water)" are the results of the dynamic viscoelasticity measurement in a water-immersed state, and the results marked "(DRY)" are the results of the dynamic viscoelasticity measurement in a dry state.

[0061] [Surface quality verification test] The polishing pad was placed at a predetermined position in the polishing device via a double-sided tape having an acrylic adhesive, and the Cu film substrate was polished under the following conditions. (polishing conditions) Polishing machine: F-REX300 (manufactured by Ebara Corporation) Disk: A188 (3M) Rotation speed: (table) 70 rpm, (top ring) 71 rpm Grinding pressure: 3.5psi Polishing agent temperature: 20℃ Abrasive discharge rate: 200ml / min Abrasive: PLANERLITE7000 (manufactured by Fujimi Corporation) Object to be polished: Cu film substrate Polishing time: 60 seconds Pad break: 35N 10 minutes Conditioning: Ex-situ, 35N, 4 scans

[0062] For the 10th to 50th polished pieces after the above polishing process, linear polishing scratches larger than 155 nm on the polished surface were visually confirmed using a ReviewSEM eDR5210 (manufactured by KLA-Tencor Corporation), and the average value was obtained. The surface quality was evaluated based on the results of scratch confirmation.

[0063] [Table 1] [Industrial Applicability]

[0064] The polishing pad of the present invention has industrial applicability as a polishing pad that can be used for polishing optical materials, semiconductor devices, substrates for hard disks, etc., and is particularly suitable for polishing devices having an oxide layer, a metal layer such as copper, etc. formed on a semiconductor wafer.

Claims

1. A polyurethane sheet is provided as the polishing layer, A polyurethane sheet is immersed in water at a temperature of 23°C for 3 days, and in a dynamic viscoelasticity measurement conducted under conditions of a frequency of 1.6 Hz and a temperature of 20 to 100°C in the submerged state, the polyurethane sheet has a peak of loss tangent tanδ in the range of 40 to 60°C, a difference A between the loss tangent tanδ at 60°C and 70°C of the polyurethane sheet is smaller than a difference B between the loss tangent tanδ at 50°C and 60°C and a difference C between the loss tangent tanδ at 70°C and 80°C; Polishing pad.

2. A difference between a difference A indicating the slope of the loss tangent tanδ at 60°C and 70°C and a difference B indicating the slope of the loss tangent tanδ at 50°C and 60°C is 0.010 to 0.040, a difference between the difference A indicating the slope of the loss tangent tanδ at 60°C and 70°C and the difference C indicating the slope of the loss tangent tanδ at 70°C and 80°C being 0.030 to 0.080; The polishing pad of claim 1 .

3. The peak value of the loss tangent tanδ is 0.15 to 0.

35. The polishing pad according to claim 1 or 2.

4. In a dynamic viscoelasticity measurement performed under conditions of a frequency of 1.6 Hz and a temperature of 20 to 100°C while immersed in water, the polyurethane sheet has a loss modulus E'' of 21 MPa or more at 40°C. The polishing pad according to any one of claims 1 to 3.

5. The polyurethane sheet contains a polyurethane resin and hollow fine particles dispersed in the polyurethane resin. The polishing pad according to any one of claims 1 to 4.

6. A polishing step of polishing an object to be polished using the polishing pad according to any one of claims 1 to 5 in the presence of a polishing slurry. A method for manufacturing polished workpieces.

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