JP2020055102A - Polishing pad and manufacturing method for polished work-piece - Google Patents

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. With respect to the polyurethane sheet, a peak value α of loss tangent tanδ 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 is larger than a peak value β of loss tangent tanδ in dynamic viscoelasticity measurement that is performed in a dry state under the condition that the frequency is 1.6 Hz and the temperature is in a range of 20-100°C.SELECTED DRAWING: None

Description

  The present invention relates to a polishing pad and a method for manufacturing a polished product.

  Polishing slurry is used on the surface (processed surface) of materials such as semiconductor devices and electronic parts, especially thin substrates (subjects to be polished) such as Si substrates (silicon wafers), hard disk substrates, glass and LCD (liquid crystal display) substrates. Is used to perform chemical mechanical polishing using a polishing pad.

  As a polishing pad used for such a polishing process, for example, a polishing pad having a polishing layer having an E ′ ratio at 30 ° C. to 90 ° C. of about 1 to 3.6 is used for the purpose of reducing dishing. (Patent Literature 1) Also, for the purpose of achieving both planarization performance and low defect performance rate, KEL energy having a porosity of 0.1% by volume, 385 to 750 l / Pa at 40 ° C. and 1 rad / sec. It is known to use a polishing pad provided as a polishing layer with a loss coefficient and a polymer material having an elastic modulus E ′ of 100 to 400 MPa at 40 ° C. and 1 rad / sec (Patent Document 2).

JP-T-2004-507076 JP 2005-136400A

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

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polishing pad and a method of manufacturing a polished product that can reduce the occurrence of scratches.

  The inventor of the present invention has made intensive studies to solve the above-mentioned problems. As a result, when dynamic viscoelasticity was measured under immersed (underwater) conditions and under dry conditions, the tan δ peak value obtained was determined to have a predetermined relationship. It has been found that the above problems can be solved by using a polyurethane sheet satisfying the above as a polishing layer, and the present invention has been completed.

That is, the present invention is as follows.
[1]
Equipped with a polyurethane sheet as a polishing layer,
The polyurethane sheet has a peak value α of loss tangent tan δ in a dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a immersed state. Greater than the peak value β of the loss tangent tan δ in the dynamic viscoelasticity measurement performed under the conditions of
Polishing pad.
[2]
A rate of change of the peak value α with respect to the peak value β is 1.03 to 1.30;
The polishing pad according to [1].
[3]
The peak value α is 0.10 or more;
The polishing pad according to [1] or [2].
[4]
The peak temperature A at the peak value α is 60 to 85 ° C.,
The polishing pad according to any one of [1] to [3].
[5]
The polyurethane sheet is subjected to a loss tangent tan δ in a dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a immersed state, and at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a dry state. The loss tangent tan δ in the dynamic viscoelasticity measurement has a temperature at which the value becomes the same, at 70 ° C. or more,
The polishing pad according to any one of [1] to [4].
[6]
The polyurethane sheet includes a polyurethane resin and hollow fine particles dispersed in the polyurethane resin,
The polishing pad according to any one of [1] to [5].
[7]
In the presence of a polishing slurry, using a polishing pad according to any one of [1] to [6], having a polishing step of polishing an object to be polished,
A method of manufacturing a polished product.

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

FIG. 4 is a diagram showing the results of dynamic viscoelasticity measurement in Example 1. FIG. 9 is a diagram showing the results of dynamic viscoelasticity measurement in Example 2. FIG. 9 is a view showing a result of dynamic viscoelasticity measurement in Example 3. FIG. 9 is a diagram showing the results of dynamic viscoelasticity measurement in Comparative Example 1. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 4. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 5. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 6. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 7. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 8. FIG. 14 is a view showing a result of dynamic viscoelasticity measurement in Example 9. FIG. 19 is a view showing a result of dynamic viscoelasticity measurement in Example 10. FIG. 19 is a view showing a result of dynamic viscoelasticity measurement in Example 11. FIG. 21 is a view showing a result of dynamic viscoelasticity measurement in Example 12. FIG. 21 is a view showing a result of dynamic viscoelasticity measurement in Example 13.

  Hereinafter, an embodiment of the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. It is.

[Polishing pad]
The polishing pad of the present embodiment includes a polyurethane sheet as a polishing layer, and the polyurethane sheet has a loss tangent tan δ peak value in a dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a submerged state. is larger than the peak value β of the loss tangent tan δ in dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a dry state.

(Loss tangent tan δ)
The loss tangent tan δ is a value represented by the ratio of the loss elastic modulus E ″ (viscous component) to the storage elastic modulus E ′ (elastic component). Under the measurement conditions, the elasticity and viscosity of the substance to be measured are measured. It is an index that indicates the balance of It is known that the loss tangent tan δ differs depending on whether a substance to be measured is in a dry state or a submerged state, and also differs depending on a frequency at the time of measurement.

  In the polishing step in which the slurry and the polishing pad are in contact, the polishing surface is in a submerged state. From this, in the present embodiment, the peak value of the loss tangent tan δ in the submerged state is higher than that in the dry state, that is, in the submerged state, the storage elastic modulus E ′ (elastic component) is higher than the loss elastic modulus E ″ ( A state in which the viscous component becomes more dominant is developed. As a result, the state of contact with the object to be polished (work) at the time of polishing is further improved, and persistent pressing of the polishing waste is suppressed, and generation of scratches is suppressed.

  Here, “the peak of the loss tangent tan δ in the dynamic viscoelasticity measurement performed at 20 to 100 ° C.” means the maximum value of the loss tangent tan δ in the range of 20 to 100 ° C. In addition, in this embodiment, “peak” means that the difference between the maximum value and the minimum value is 0.05 or more in a temperature range of the maximum value ± 5 ° C. Is not interpreted as a peak.

  More specifically, the difference between the peak value β and the peak value α is preferably 0.003 to 0.080, more preferably 0.005 to 0.080, and even more preferably 0.010 to 0. 0.080, particularly preferably 0.015 to 0.080. The degree of peak increase from the peak value β of the loss tangent tan δ in the dry state to the peak value α of the loss tangent tan δ in the flooded state, that is, the rate of change of the peak value α with respect to the peak value β is preferably 1.03. To 1.50, more preferably 1.05 to 1.50, still more preferably 1.05 to 1.30, and particularly preferably 1.05 to 1.25. When the difference between the peak value β and the peak value α and the rate of change of the peak value α with respect to the peak value β are within the above range, the loss elastic modulus E ′ (elastic component) with respect to the storage elastic modulus E ′ (elastic component) in a flooded state. The state where '(viscous component) becomes more dominant effectively appears, and the generation of scratches tends to be further suppressed.

  The peak value α of the loss tangent tan δ at the peak temperature A is preferably 0.10 or more, more preferably 0.15 or more, further preferably 0.16 to 0.35, and particularly preferably 0.1 to 0.35. 16 to 0.20. The peak value β of the loss tangent tan δ at the peak temperature B is preferably 0.10 to 0.35, more preferably 0.12 to 0.25, and further preferably 0.13 to 0.18. , And still more preferably 0.13 to 0.17, still more preferably 0.13 to 0.16, and particularly preferably 0.13 to 0.15. When the peak value α and the peak value β are within the above ranges, a state in which the loss elastic modulus E ″ (viscous component) is more superior to the storage elastic modulus E ′ (elastic component) in a submerged state is effective. And the occurrence of scratches tends to be further suppressed.

  The peak temperature A at the peak value α is preferably from 60 to 85 ° C, more preferably from 60 to 80 ° C, further preferably from 60 to 75 ° C, and particularly preferably from 65 to 75 ° C. Further, the peak temperature B at the peak value β is preferably from 65 to 100 ° C, more preferably from 75 to 95 ° C, further preferably from 78 to 95 ° C, and still more preferably from 80 to 95 ° C. And particularly preferably from 85 to 95 ° C. Since the peak of the loss tangent tan δ is within the above temperature range, the loss elastic modulus E ″ (viscous component) is more superior to the storage elastic modulus E ′ (elastic component) in a temperature range close to the temperature of the polishing step. And the occurrence of scratches tends to be further suppressed.

  From the viewpoint of developing a state in which the loss elastic modulus E ″ (viscous component) is superior to the storage elastic modulus E ′ (elastic component) in the flooded state, the dynamic viscoelasticity measurement in the flooded state is considered. It is preferable that the temperature range where the value of the loss tangent tan δ is larger than the value of the loss tangent tan δ in the dynamic viscoelasticity measurement in a dry state overlaps with the temperature of the polishing step. From such a viewpoint, in a immersed state, a loss tangent tan δ in dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C., and in a dry state at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. The temperature at which the loss tangent tan δ in the dynamic viscoelasticity measurement to be performed has the same value (hereinafter, also referred to as “intersection temperature”) can be adjusted. More specifically, the intersection point temperature is preferably 70 ° C. or higher, preferably 70 ° C. or higher, more preferably 72 to 90 ° C., and even more preferably 75 to 90 ° C. Since the intersection point temperature is 70 ° C. or higher, in a temperature range lower than 70 ° C., the value of the loss tangent tan δ in the dynamic viscoelasticity measurement in a submerged state is smaller than the value of the loss tangent tan δ in the dynamic viscoelasticity measurement in a dry state. The temperature range becomes larger. Therefore, a state in which the loss elastic modulus E ″ (viscous component) is superior to the storage elastic modulus E ′ (elastic component) in the submerged state is more effectively expressed, and the occurrence of scratches tends to be further suppressed. is there.

  The dynamic viscoelasticity measurement of the present embodiment can be performed according to an ordinary method. In the dynamic viscoelasticity measurement in a submerged 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 while immersed in the sample. Further, in the measurement of dynamic viscoelasticity in a dry state, a polishing layer held for 40 hours in a thermo-hygrostat at a temperature of 23 ° C. (± 2 ° C.) and a relative humidity of 50% (± 5%) was used as a sample, and The sample is measured under a normal air atmosphere (dry state). An example of a dynamic viscoelasticity measuring device capable of performing such a measurement is DMA8000 manufactured by PerkinElmer Japan. Other conditions are not particularly limited, but can be measured under the conditions described in Examples.

(Polyurethane sheet)
A polyurethane sheet is used as the polishing layer having the above characteristics. The polyurethane resin constituting the polyurethane sheet is not particularly limited, and examples thereof include a polyester-based polyurethane resin, a polyether-based polyurethane resin, and a polycarbonate-based polyurethane resin. These may be used alone or in combination of two or more.

  The 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 resins can be applied. Here, the urethane prepolymer is not particularly limited. For example, an adduct of hexamethylene diisocyanate and hexanetriol; an adduct of 2,4-tolylene diisocyanate and prenzcatechol; tolylene diisocyanate and hexanetriol Adduct of tolylene diisocyanate with trimethylolpropane; adduct of xylylene diisocyanate with trimethylolpropane; adduct of hexamethylene diisocyanate with trimethylolpropane; and addition of isocyanuric acid with hexamethylene diisocyanate Things. In addition, an isocyanate group-containing compound prepared by reacting a polyisocyanate compound with 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.

The polyisocyanate compound used for the isocyanate group-containing compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, as a diisocyanate compound having two isocyanate groups in a molecule, 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 (cyclohexylisocyanate) (hydrogenated MDI), 3,3'- Dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate Ne Propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, p-phenylenediisothiocyanate, xylylene-1,4-diiso Thiocyanate, ethylidene diisothiocyanate and the like can be mentioned.
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.
The polyisocyanate compound preferably contains 2,4-TDI and / or 2,6-TDI, and more preferably contains 2,4-TDI and 2,6-TDI. It is even more preferred that they consist solely 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, and 90:10 to 70:30. Is even more preferably 80:20.

  Examples of the polyol compound used for the isocyanate group-containing compound include diol compounds such as ethylene glycol, diethylene glycol (DEG) and butylene glycol, and triol compounds; and polyols such as polypropylene glycol (PPG) and poly (oxytetramethylene) glycol (PTMG). Ether polyol compounds; polyester polyol compounds such as a reaction product of ethylene glycol and adipic acid and a reaction product of butylene glycol and adipic acid; polycarbonate polyol compounds, polycaprolactone polyol compounds, and the like. Further, trifunctional propylene glycol to which ethylene oxide has been added can also be used. Among these, PTMG is preferable, and it is also preferable to use PTMG in combination with DEG. The number average molecular weight (Mn) of PTMG is preferably from 500 to 2,000, more preferably from 600 to 1300, even more preferably from 650 to 1,000. The loss tangent tan δ in the submerged state and the dry state can be adjusted by the molecular weight of the polyol compound or the combination of the polyol compound used. The number average molecular weight can be measured by gel permeation chromatography (GPC). When the number average molecular weight of the polyol compound is measured from the polyurethane resin, it can be estimated by GPC after decomposing each component by a conventional method such as amine decomposition. The polyol compound may be used alone, or a plurality of polyol compounds may be used in combination.

  The NCO equivalent of the urethane prepolymer is preferably 300 to 700, more preferably 350 to 600, and still more preferably 400 to 500. The “NCO equivalent” is “(parts by mass of polyisocyanate compound / 10 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 polyol compound molecule × 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.

  The curing agent is not particularly limited, but for example, 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- (isopropylamino) -4-hydroxyphenyl] propane, 2,2-bis [3- (1-methylpropylamino) -4-hydroxy Phenyl] propane, 2,2-bis [3- (1-methylpentylamino) -4-hydroxyphenyl] Lopan, 2,2-bis (3,5-diamino-4-hydroxyphenyl) propane, 2,6-diamino-4-methylphenol, trimethylethylenebis-4-aminobenzoate, and polytetramethylene oxide-di- polyhydric amine compounds such as p-aminobenzoate; 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- Dimethyl trimethylene glycol, tetra Tylene 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) Examples include polyhydric alcohol compounds such as glycol, polyethylene glycol, and polypropylene glycol. Further, the polyamine compound may have a hydroxyl group. Examples of such an amine compound include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, and di-2. -Hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine and the like.

  As the polyvalent amine compound, a diamine compound is preferable, and 3,3'-dichloro-4,4'-diaminodiphenylmethane is particularly preferable. As the polyhydric alcohol compound, among these, polypropylene glycol is preferable, polypropylene glycol having a number average molecular weight of 1,000 to 3,000 is more preferable, and polypropylene glycol having a number average molecular weight of 1,500 to 2,500 is still more preferable. The curing agents may be used alone or in combination of two or more.

  The curing agent is preferably added in an amount of 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, more preferably 20 to 40 parts by mass, based on 100 parts by mass of the urethane prepolymer. More preferred.

  Depending on the molecular weight (degree of polymerization) of the urethane prepolymer and the combination of the urethane prepolymer and the curing agent, the loss tangent tan δ in the immersed state and the dried state can be adjusted. From such a viewpoint, for example, 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. It is preferable to mix each component so as to be 0.70 to 1.30, more preferably 0.75 to 1.20, still more preferably 0.80 to 1.10, and 0.80 to 1.00. Even more preferably, 0.85 to 0.95 is even more preferable.

  The polyurethane sheet is preferably a foamed polyurethane sheet having cells. Further, the cells of the foamed polyurethane sheet are classified into closed cells in which a plurality of cells are independently present and open cells in which a plurality of cells are connected by a communication hole depending on the mode. Among these, the polyurethane sheet of the present embodiment preferably has closed cells, and is more preferably a polyurethane sheet containing a polyurethane resin and hollow fine particles dispersed in the polyurethane resin. By using the hollow fine particles, the peak temperature of the loss tangent tan δ tends to be easily adjusted.

  The polyurethane sheet having closed cells can be formed by using hollow fine particles having an outer shell and having a hollow inside. As the hollow fine particles, commercially available ones may be used, and those obtained by synthesizing by a conventional method may be used. Although the material of the outer shell of the hollow fine particles is not particularly limited, for example, polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylic acid, polyacrylamide, polyethylene glycol, polyhydroxyether acrylite, maleic acid copolymer, polyethylene oxide , Polyurethane, poly (meth) acrylonitrile, polyvinylidene chloride, polyvinyl chloride, organic silicone resins, and copolymers obtained by combining two or more kinds of monomers constituting those resins. Examples of commercially available hollow microparticles 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. .

  The shape of the hollow fine particles in the polyurethane sheet is not particularly limited, and may be, for example, spherical and substantially 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 10 to 35 μm. The use of such hollow fine particles can also adjust the loss tangent tan δ in a submerged state and a dry state. The average particle size can be measured by a laser diffraction type particle size distribution analyzer (for example, Mastersizer-2000, manufactured by Spectris Co., Ltd.).

  The hollow fine particles are added so as to be preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, and still more preferably 1 to 3 parts by mass with respect to 100 parts by mass of the urethane prepolymer.

  In addition to the above components, a foaming agent conventionally used may be used in combination with the hollow fine particles as long as the effects of the present invention are not impaired. You may inject | pour a neutral gas. Examples of the foaming agent include water and a foaming agent mainly containing 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. Further, in addition to the above components, known foam stabilizers, flame retardants, coloring agents, plasticizers and the like may be added.

  The method for producing the polyurethane sheet is not particularly limited, and includes, for example, a method in which a urethane prepolymer is reacted with a curing agent to form a polyurethane resin block, and the sheet is cut out from the obtained polyurethane resin block. In the mixing step, the urethane prepolymer and the curing agent are supplied into a mixer and stirred and mixed. When hollow fine particles are used, a polyurethane resin block incorporating the hollow fine particles can be obtained by mixing the urethane prepolymer, the curing agent, and the hollow fine particles. The order of mixing is not particularly limited, but it is preferable to mix the urethane prepolymer and the hollow fine particles first, and then supply the curing agent into the mixing machine. Thus, a mixed solution for the polyurethane resin block is prepared. The mixing step is performed in a state where the components are heated to a temperature at which the fluidity of each component can be ensured.

  For example, a curing agent is put into a jacketed mixer capable of controlling the temperature, and the mixture is stirred at 30 to 130 ° C. to a solution of a urethane prepolymer (for example, an isocyanate group-containing compound) heated to 30 to 90 ° C. containing hollow fine particles. . If necessary, the mixture may be received in a jacketed tank with a stirrer and aged. The stirring time is appropriately adjusted depending on the number of teeth, the number of revolutions, the clearance and the like of the mixer, and is, for example, 0.1 to 60 seconds.

  In the molding step, the mixture for the polyurethane resin block prepared in the mixing step is poured into a mold preheated to 30 to 100 ° C., and is heated and cured at about 100 to 150 ° C. for about 10 minutes to 5 hours. A polyurethane resin block is formed. At this time, the urethane prepolymer and the curing agent react to form a polyurethane resin, whereby the mixed liquid is cured in a state where bubbles and / or hollow fine particles are dispersed in the polyurethane resin. Thereby, a polyurethane resin block including a large number of substantially spherical bubbles is formed.

  The polyurethane resin block obtained by the molding step is then sliced into a sheet to form a polyurethane sheet. By slicing, an opening is provided on the sheet surface. At this time, aging may be performed at 30 to 150 ° C. for about 1 hour to 24 hours in order to form openings on the surface of the polishing layer which are excellent in abrasion resistance and are not easily clogged.

  The polishing layer having the polyurethane sheet obtained in this manner is thereafter applied with a double-sided tape on the surface opposite to the polishing surface of the polishing layer, cut into a predetermined shape, preferably a disc shape, The polishing pad according to the embodiment is completed. The double-sided tape is not particularly limited, and can be arbitrarily selected from double-sided tapes known in the art.

  Further, the polishing pad of the present embodiment may have a single-layer structure composed of only the polishing layer, and may have a multilayer structure in which another layer (lower layer, support layer) is bonded to the surface of the polishing layer opposite to the polishing surface. It may consist of layers. The characteristics of the other layers are not particularly limited, and when a layer softer than the polishing layer (having a smaller A hardness or D hardness) is bonded to the surface on the opposite side of the polishing layer, the polishing flatness is further improved. I do. On the other hand, when a layer harder than the polishing layer (having a higher A hardness or a higher D hardness) is attached to the surface on the opposite side of the polishing layer, the polishing rate is further improved.

  In the case of having a multi-layer structure, a plurality of layers may be bonded and fixed to each other using a double-sided tape or an adhesive while applying pressure as necessary. There are no particular restrictions on the double-sided tape or adhesive used at this time, and any one of double-sided tapes and adhesives known in the art can be used.

  Further, the polishing pad of the present embodiment may be subjected to a grinding process, a grooving process, an embossing process, or a hole process (punching process) on the front surface and / or the back surface of the polishing layer, if necessary. And / or an adhesive layer may be bonded to the polishing layer, and a light transmitting portion may be provided. The grinding method is not particularly limited, and the grinding can be performed by a known method. Specifically, grinding with sandpaper is mentioned. There is no particular limitation on the shape of the groove processing and the embossing processing, and examples thereof include a lattice type, a concentric type, and a radial type.

(Manufacturing method of polished product)
The method for manufacturing a polished product according to the present embodiment includes a polishing step of polishing an object to be polished using the polishing pad in the presence of a polishing slurry to obtain a polished product. The polishing step may be a primary polishing (coarse polishing), a final polishing, or a combination of both polishing. Among them, the polishing pad of the present embodiment is preferably used for chemical mechanical polishing. Hereinafter, the method of manufacturing a polished product of the present embodiment will be described by taking chemical mechanical polishing as an example, but the method of manufacturing a polished product of the present embodiment is not limited to the following.

  In this manufacturing method, with the supply of the polishing slurry, the holding platen and the polishing platen are relatively rotated while pressing the object to be polished with the holding platen toward the polishing pad side, so that the object to be polished is The processing surface is polished by chemical mechanical polishing (CMP) with a polishing pad. The holding platen and the polishing platen may rotate in the same direction at different rotational speeds, or may rotate in different directions. The object to be polished may be polished while moving (rotating) inside the frame portion during the polishing.

The polishing slurry includes chemical components such as water and an oxidizing agent represented by hydrogen peroxide, additives, and abrasive grains (abrasive particles; for example, SiC, SiO ₂ , and Al ₂ O) depending on an object to be polished and polishing conditions. ₃ , CeO ₂ ) and the like.

  The object to be polished is not particularly limited. For example, materials such as semiconductor devices and electronic parts, particularly thin substrates such as Si substrates (silicon wafers), hard disk substrates, glass and LCD (liquid crystal display) substrates, etc. (Substrate to be polished). Among them, the method for manufacturing a polished product according to the present embodiment can be suitably used as a method for manufacturing a semiconductor device having a metal layer such as an oxide layer and copper formed thereon.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited at all by the following Examples.

[Example 1]
NCO obtained by reacting tolylene diisocyanate (a mixture of 80% by mass of 2,4-TDI and 20% by mass of 2,6-TDI), poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, and diethylene glycol (DEG) Expanded hollow fine particles (average particle size: 30 to 50 μm in particle size in which the shell portion is made of acrylonitrile-vinylidene chloride copolymer and the shell size is 30 to 50 μm in 100 parts of urethane prepolymer having an equivalent weight of 440) : 40 μm), and 1.7 parts were added and mixed to obtain a urethane prepolymer mixed solution. The obtained urethane prepolymer mixture was charged into a first liquid tank and kept at 80 ° C. Also, 27 parts of 3,3'-dichloro-4,4'-diaminodiphenylmethane (methylenebis-o-chloroaniline) (MOCA) as a curing agent was put into the second liquid tank, heated and melted at 120 ° C., and further decompressed under reduced pressure. Foaming gave a hardener melt.

  Next, the respective liquids of the first liquid tank and the second liquid tank were injected from the respective injection ports of the mixer having two injection ports, and were mixed by stirring to obtain a mixed liquid. At this time, the mixing ratio was adjusted so that the R value representing the equivalent ratio of the amino group and the hydroxyl group present in the curing agent to the isocyanate group present at the terminal in the urethane prepolymer was 0.90.

  The obtained mixed liquid was poured into a mold preheated to 100 ° C., and primary cured at 110 ° C. for 30 minutes. The formed block-shaped molded product was pulled out of the mold and subjected to secondary curing in an oven at 130 ° C. for 2 hours to obtain a urethane resin block. After the obtained urethane resin block was allowed to cool to 25 ° C., it was heated again in an oven at 120 ° C. for 5 hours, and then subjected to a slice treatment to obtain a foamed polyurethane sheet. A double-sided tape was attached to the back surface of the obtained polyurethane sheet, and used as a polishing pad.

[Example 2]
NCO obtained by reacting tolylene diisocyanate (a mixture of 80% by mass of 2,4-TDI and 20% by mass of 2,6-TDI), poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, and diethylene glycol (DEG) To 100 parts of an urethane prepolymer having an equivalent weight of 460, 2.4 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixed solution. Further, as a curing agent, 26 parts of MOCA were heated and melted and mixed to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 3]
To 100 parts of the urethane prepolymer of Example 1, 2.1 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 27 parts of MOCA and 4.8 parts of polypropylene glycol were heated and melted and mixed to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

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

[Example 4]
It is obtained by reacting 2,4-tolylene diisocyanate, poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1,000, and diethylene glycol (DEG). 100 parts of a urethane prepolymer having an NCO equivalent of 440, a shell portion made of an acrylonitrile-vinylidene chloride copolymer, and particles having an isobutane gas encapsulated in the shell have a size of 5 to 15 μm (average particle size: 8.5 μm). Was added and mixed to obtain a urethane prepolymer mixed liquid. 27 parts of MOCA as a curing agent was heated and melted, and further defoamed under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 5]
It is obtained by reacting 2,4-tolylene diisocyanate, poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 650, poly (oxytetramethylene) glycol (PTMG) having a number average molecular weight of 1,000, and diethylene glycol (DEG). To 100 parts of a urethane prepolymer having an NCO equivalent of 460, 3.4 parts of the same hollow fine particles as those used in Example 4 were added and mixed to obtain a urethane prepolymer mixed solution. As a curing agent, 26 parts of MOCA were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 6]
To 100 parts of the urethane prepolymer of Example 5, 1.8 parts of the same hollow fine particles as those used in Example 4 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 26 parts of MOCA were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 7]
To 100 parts of the urethane prepolymer of Example 5, 2.5 parts of the same hollow fine particles as those used in Example 4 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 26 parts of MOCA were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

Example 8
To 100 parts of the urethane prepolymer of Example 5, 2.1 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 27 parts of MOCA and 8.7 parts of polypropylene glycol were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 9]
In the 100 parts of the urethane prepolymer of Example 5, the shell portion is made of acrylonitrile-vinylidene chloride copolymer, and the particles having isobutane gas encapsulated in the shell have an expansion of 15 to 25 μm (average particle size: 20 μm). 3.0 parts of the hollow fine particles thus obtained were added and mixed to obtain a urethane prepolymer mixed liquid. As a curing agent, 25.8 parts of MOCA and 8.6 parts of polypropylene glycol were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 10]
To 100 parts of the urethane prepolymer of Example 5, 3.0 parts of the same hollow fine particles as those used in Example 4 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 25.8 parts of MOCA and 8.6 parts of polypropylene glycol were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 11]
To 100 parts of the urethane prepolymer of Example 4, 1.7 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixture. 27 parts of MOCA as a curing agent was heated and melted, and further defoamed under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 12]
To 100 parts of the urethane prepolymer of Example 5, 2.4 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 26 parts of MOCA were heated and melted, followed by defoaming under reduced pressure to obtain a curing agent melt. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

[Example 13]
To 100 parts of the urethane prepolymer of Example 4, 2.1 parts of the same hollow fine particles as those used in Example 1 were added and mixed to obtain a urethane prepolymer mixture. As a curing agent, 27 parts of MOCA and 4.8 parts of polypropylene glycol were heated and melted, followed by defoaming under reduced pressure to obtain a melt of the curing agent. A polishing pad was obtained in the same manner as in Example 1 using the urethane prepolymer mixed liquid and the curing agent melt liquid.

(Dynamic viscoelasticity measurement)
The dynamic viscoelasticity of the polyurethane sheet was measured under the following conditions. First, a polyurethane sheet was immersed in water at a temperature of 23 ° C. for 3 days. Using the obtained polyurethane sheet as a sample, a dynamic viscoelasticity measurement was performed in water (submerged state). As a dynamic viscoelasticity measuring device, DMA8000 (manufactured by PerkinElmer Japan) was used.
(Measurement condition)
Measuring device: DMA8000 (manufactured by PerkinElmer Japan)
Sample: 4cm long x 0.5cm wide x 0.125cm thick
Test length: 1cm
Pretreatment of sample: kept in water at a temperature of 23 ° C. for 3 days Test mode: tensile frequency: 1.6 Hz (10 rad / sec)
Temperature range: 20-100 ° C
Heating rate: 5 ° C / min
Strain range: 0.10%
Initial load: 148g
Measurement interval: 1 point / ° C

  Further, a polyurethane sheet in a dry state in which the polyurethane sheet was held for 40 hours in a thermo-hygrostat at a temperature of 23 ° C. (± 2 ° C.) and a relative humidity of 50% (± 5%) was used as a sample under a normal air atmosphere ( (In a dry state). The measurement was carried out under the same conditions as above, except that RSA3 (manufactured by TA Instruments) was used as the other device. The results of the dynamic viscoelasticity measurement of Examples and Comparative Examples are shown in FIGS. In the figure, what is described as (underwater) is the result of the dynamic viscoelasticity measurement in a submerged state, and what is described as (DRY) is the result of the dynamic viscoelasticity measurement in a dry state. .

(Surface quality confirmation test)
The polishing pad was set at a predetermined position of the polishing apparatus 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: (stable plate) 70 rpm, (top ring) 71 rpm
Polishing pressure: 3.5 psi
Abrasive temperature: 20 ° C
Abrasive discharge rate: 200 ml / min
Abrasive: PLANERLITE7000 (manufactured by Fujimi Corporation)
Polishing object: Cu film substrate Polishing time: 60 seconds Pad break: 35N 10 minutes Conditioning: Ex-situ, 35N, 4 scans

  From the tenth to the fiftieth workpieces after the above-mentioned polishing, polishing scratches (scratch) larger than 155 nm on the surface to be polished were visually confirmed with a Review SEM of eDR5210 (manufactured by KLA Tencor), and the average value was determined. Obtained. The surface quality was evaluated based on the confirmation result of the scratch.

  The polishing pad of the present invention is used for polishing optical materials, semiconductor devices, substrates for hard disks, etc., and is particularly suitable for polishing devices in which an oxide layer, a metal layer such as copper, etc. are formed on a semiconductor wafer. It has industrial applicability as a polishing pad used for polishing.

Claims (7)

Equipped with a polyurethane sheet as a polishing layer,
The polyurethane sheet has a peak value α of loss tangent tan δ in a dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a immersed state. Greater than the peak value β of the loss tangent tan δ in the dynamic viscoelasticity measurement performed under the conditions of
Polishing pad. A rate of change of the peak value α with respect to the peak value β is 1.03 to 1.30;
The polishing pad according to claim 1. The peak value α is 0.10 or more;
The polishing pad according to claim 1. The peak temperature A at the peak value α is 60 to 85 ° C.,
The polishing pad according to claim 1. The polyurethane sheet is subjected to a loss tangent tan δ in a dynamic viscoelasticity measurement performed at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a immersed state, and at a frequency of 1.6 Hz and a temperature of 20 to 100 ° C. in a dry state. The loss tangent tan δ in the dynamic viscoelasticity measurement has a temperature at which the value becomes the same, at 70 ° C. or more,
The polishing pad according to claim 1. The polyurethane sheet includes a polyurethane resin and hollow fine particles dispersed in the polyurethane resin,
The polishing pad according to claim 1. In the presence of a polishing slurry, using the polishing pad according to any one of claims 1 to 6, having a polishing step of polishing the object to be polished,
A method of manufacturing a polished product.