WO2015037606A1

WO2015037606A1 - Polishing pad and method for manufacturing same

Info

Publication number: WO2015037606A1
Application number: PCT/JP2014/073896
Authority: WO
Inventors: 博仁宮坂; 哲平立野; 香枝喜樂; 立馬松岡
Original assignee: 富士紡ホールディングス株式会社
Priority date: 2013-09-11
Filing date: 2014-09-10
Publication date: 2015-03-19
Also published as: TW201519994A; JP6567420B2; JPWO2015037606A1; TWI648129B

Abstract

　A polishing pad provided with a plastic sheet, wherein after a prescribed polishing test, the polishing surface of the sheet has a roughness curve skewness (Rsk) of -2.00 to -0.20, and a height distribution variation coefficient of 0.5-2.5 %.

Description

Polishing pad and manufacturing method thereof

The present invention relates to a polishing pad and a manufacturing method thereof, and more particularly to a polishing pad for finishing and a manufacturing method thereof.

Bare silicon, semiconductor devices, magnetic disk substrates, etc. are polished to smooth their surfaces. Such polishing is a process in which a polishing pad (slurry) in which abrasive grains are dispersed in an alkaline solution or the like is supplied to a surface to be polished and a polishing pad is pressed against the surface to be polished and rotated. This is called polishing (hereinafter referred to as “CMP”).

The polishing pad is made of various materials depending on the required smoothness. Generally, a polyurethane foam sheet formed by a wet film forming method is often used for a polishing pad for finishing (see, for example, Patent Document 1). For polishing pads used for final finishing of semiconductor devices and the like that are becoming finer, demands for defect-free and flattening are increasing. For example, scratches that have not been a problem as a result of miniaturization become fatal defects, and therefore, polishing processing with such low damage is required.

Also, in the CMP technique, it is necessary to stabilize the polishing rate from the viewpoint of increasing the efficiency of productivity and improving the yield. Since the polishing rate is greatly influenced by the contact state between the surface to be polished of the object to be polished and the polishing pad, the surface state of the polishing pad is likely to change at the initial stage of polishing, and the polishing rate is not stable.

Therefore, conventionally, a method of keeping the polishing pad wet (see Patent Document 2) or a method of controlling the surface roughness of the polishing pad (Patent Document 2) in order to shorten the time during which the initial polishing rate is unstable. 3 and 4).

JP 2002-059356 A JP 2009-148876 A JP 2010-253665 A JP 2009-154291 A

As a polishing process with low damage, a method of polishing with a soft polishing pad using a polishing slurry containing a silica-based or alumina-based abrasive having a small particle size is considered effective. By using a polishing slurry with a chemical element higher than that of a mechanical element and polishing with a soft polishing pad, the stress in the local microregion can be dispersed in the object to be polished at the time of polishing. The degree of contact between the abrasive grains and the polishing product that come into contact can be reduced, and scratches can be reduced. However, when the contribution of chemical components contained in the polishing slurry is increased, the polishing pad is likely to be deteriorated. In particular, in the case of a softened polishing pad containing polyurethane, since the polyurethane has few cross-linking points and is structurally weak, there is a further concern about deterioration due to the polishing slurry.

In addition, in the methods described in Patent Documents 2 to 4, after performing dressing for the purpose of improving clogging of the polishing slurry during polishing, or after temporarily stopping the polishing process and waiting in a wet state When the polishing process is resumed, the surface state of the polishing pad or the amount of abrasive grains retained changes. As a result, for a while after resuming the polishing process, the average polishing rate of the entire object to be polished decreases, or the uniformity of the polishing rate profile deteriorates, making it difficult to obtain a stable polishing rate. In order to stabilize the polishing rate, it is more effective that the surface of the polishing pad is always in the same state. In other words, a polishing pad in which the surface state during polishing is difficult to change is desirable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing pad that can quickly stabilize the polishing rate at the initial stage of polishing and that suppresses fluctuations in the polishing rate, and a method for manufacturing the same. .

As a result of intensive studies to achieve the above object, the inventors of the present invention can quickly stabilize the polishing rate at the initial stage of polishing because the polishing surface of the polishing pad has a predetermined surface property, and The inventors have found that the fluctuation of the polishing rate can be suppressed and have completed the present invention.

That is, the polishing pad of the present invention is a polishing pad comprising a resin sheet, and the polishing surface of the sheet after undergoing a predetermined polishing test has a roughness of −2.00 or more and −0.20 or less. It has a skewness Rsk of a curve and a height distribution variation coefficient of 0.5% or more and 2.5% or less. In the polishing pad of the present invention, the sheet preferably has a durometer hardness (type A) of 0 to 25, preferably a wet film formed, and a resin contained in the sheet is 3.0 MPa to 10 MPa. It is preferable to have a 100% modulus of 0.0 MPa. The resin includes a second resin having a bond generated by a reaction between an active hydrogen atom in the first resin having an active hydrogen atom and an isocyanate group derived from a blocked isocyanate compound, and the bond is bonded to the first resin. It is preferable to have 2.0 to 15.0 parts by mass in terms of a blocked isocyanate compound with respect to 100 parts by mass. Furthermore, the blocked isocyanate compound is preferably one obtained by blocking one or more compounds selected from the group consisting of polyvalent isocyanate compounds other than aromatic polyvalent isocyanate compounds with a blocking agent. Further, the first resin is preferably a polyurethane resin.

The manufacturing method of the polishing pad of the present invention is the manufacturing method of the polishing pad of the present invention, wherein the sheet provided in the polishing pad contains the second resin, the first resin having active hydrogen atoms and the block A step of coagulating and regenerating the first resin in the resin solution containing the isocyanate compound and the solvent, and reacting the active hydrogen atom of the first resin with the isocyanate group derived from the blocked isocyanate compound to obtain the second resin The second resin has a bond produced by a reaction between an active hydrogen atom and an isocyanate group in an amount of 2.0 to 15 parts by mass in terms of a blocked isocyanate compound with respect to 100 parts by mass of the first resin. It has 0 part by mass.

According to the present invention, it is possible to provide a polishing pad that can quickly stabilize the polishing rate in the initial stage of polishing and suppress the fluctuation of the polishing rate, and a method for manufacturing the same.

It is a conceptual diagram which shows the cross section of the surface vicinity of the resin sheet from which skewness differs mutually. It is an electron micrograph which shows the cross section of the surface vicinity of the resin sheet which concerns on this invention. It is an electron micrograph which shows the cross section of the surface vicinity of the resin sheet which concerns on a comparative example.

Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. However, the present invention is limited to the following embodiment. It is not a thing. The present invention can be variously modified without departing from the gist thereof.

The polishing pad of this embodiment is a polishing pad provided with a sheet made of resin (hereinafter also simply referred to as “resin sheet”), and the polishing surface of the resin sheet after passing through a predetermined polishing test is -2. It has a skewness of a roughness curve of 00 or more and −0.20 or less (hereinafter simply referred to as “Rsk”), and a height distribution variation coefficient of 2.5% or less.

The resin sheet has a polished surface, and the Rsk after the predetermined polishing test is −0.20 or less, preferably −0.25 or less, and −0.30 or less. More preferably, it is more preferably −0.35 or less. Further, Rsk after passing through a predetermined polishing test is preferably −2.00 or more, more preferably −1.90 or more. Further, the polished surface of the resin sheet has a coefficient of variation in height distribution after passing a predetermined polishing test of 2.5% or less, preferably 2.0% or less, and more preferably 1.5% or less. Preferably, it is more preferably 1.3% or less, and particularly preferably 1.2% or less. Further, the lower limit is preferably as small as possible, but the height distribution variation coefficient is preferably 0.5% or more, more preferably 0.7% or more. Here, Rsk and the height distribution variation coefficient are parameters obtained by measuring the resin portion of the polished surface of the resin sheet and are closely related to tribology (friction). In addition, when the resin sheet has a plurality of bubbles and the polishing surface has an opening portion derived from the bubbles, Rsk and the height distribution variation coefficient are measured on the resin portion of the polishing surface excluding the opening portion. It is a thing.

The “predetermined polishing test” means a polishing test that imitates the pad surface after polishing the dummy wafer before the main polishing, and is performed using the polishing pad under the following conditions. That is, the polishing pad after the predetermined polishing test represents the surface state of the polishing pad used in the polishing test.
-Polishing machine: Model number "F-REX300" manufactured by Ebara Manufacturing Co., Ltd.
Polishing head: manufactured by Ebara Manufacturing Co., Ltd., model number “GII”
・ Polishing slurry: manufactured by Cabot, model number “SS-25”, 20 times dilution ・ Polished object: 300 mmφ silicon wafer with silica film ・ Polishing pad diameter: 740 mmφ
・ Pad break-in conditions: 100 N × 10 minutes, diamond dresser # 100 (pellet type) rotation speed 20 rpm, surface plate rotation speed 80 rpm, ultrapure water supply amount 500 mL / min ・ Polishing conditions: surface plate rotation speed 70 rpm, polishing head rotation 71 rpm, polishing slurry flow rate 200 mL / min, polishing time 60 minutes (10 minutes × 6 wafers), polishing pressure 2.5 psi (1.7 × 10 ⁴ Pa)

Rsk is a value obtained by normalizing the third moment around the average value by Rq3 (the cube of the root mean square roughness), and the deviation of the surface roughness from the average line m, that is, the asymmetry around the average value (convex) It is an index indicating the objectivity of the concave. The closer the cross-sectional shape of the polished surface is to a curve showing repetition of normal distribution in both positive and negative directions with respect to the average line m of surface roughness, Rsk approaches 0. On the other hand, as the cross-sectional shape of the polished surface is biased in the positive direction or in the negative direction, Rsk is separated from 0. When Rsk is positive, it means that the roughness is convex upward (mountain), and there are many protrusions. On the contrary, Rsk being negative means that the roughness is convex downward (valley), and there are many flat portions on the surface. When Rsk becomes negative, it means that the resin sheet has a recess for holding the slurry. Further, it means that the smaller the value (the larger the absolute value), the smoother (flattening) the flat region other than the concave portion becomes wider and wider. That is, when the Rsk of the polished surface is −0.20 or less, it means that the amount of slurry retained is increased. As a result, when the polishing pad of this embodiment provided with such a resin sheet is used, it becomes easy to stabilize the polishing rate. Further, the polishing pad of this embodiment provided with such a resin sheet is easy to smooth because the convex part of the polishing surface is removed after the dressing process and the concave part and the flat region are formed easily, and the smoothness is maintained even by the polishing process. Since the surface state of the polished surface hardly changes, the polishing rate at the initial stage of polishing can be quickly stabilized. On the other hand, if Rsk is larger than −0.20, the number of concave portions is too small and the amount of slurry retained is reduced, and it takes a considerable time to stabilize the polishing rate at the initial stage of polishing. Further, when Rsk is −2.00 or more, it is possible to more effectively prevent the amount of slurry retained and the polishing rate from being lowered because the number of concave portions is too small.

FIG. 1 is a diagram schematically showing a cross section near the surface of a resin sheet. The smaller the value of Rsk, the closer to the shape shown in (a), and the larger the value, the closer to the shape shown in (b).

The height distribution variation coefficient is obtained by dividing the standard deviation σ of the height of the polishing surface of the polishing pad by the average of the height, and is an index indicating the smoothness of the polishing surface. Since the height measurement varies depending on the measurement location, the height distribution variation coefficient is obtained by subtracting the variation due to the measurement point. When the height distribution variation coefficient is 2.5% or less, the smoothness of the polished surface can be transferred to the object to be polished, and the object to be polished can be highly planarized. When the height distribution variation coefficient exceeds 2.5%, the surface unevenness is large, and the object to be polished cannot be flattened to a high degree.

Rsk and height distribution variation coefficient can be measured according to the method described in the examples. In addition, in order for the polished surface of the resin sheet after undergoing a predetermined polishing test to have Rsk and height distribution variation coefficient in the above numerical range, for example, when a resin sheet is obtained by a wet film forming method, a block described later An isocyanate compound may be appropriately selected and used. At that time, by considering the chain length of the portion other than the blocking agent of the blocked isocyanate compound and the flexibility of the molecule, the polishing surface can be more easily adjusted to the Rsk and the height distribution within the above numerical range by appropriately adjusting the amount used. A resin sheet having a coefficient of variation can be obtained.

The surface roughness (arithmetic mean roughness: Ra) of the resin sheet after undergoing a predetermined polishing test is not particularly limited, but from the viewpoint of more effectively and reliably achieving the effects of the present invention, 1.0 to 10. It is preferably 0 μm, more preferably 2.0 to 8.0 μm, and even more preferably 2.0 to 5.0 μm. The surface roughness can be measured according to the method described in the examples.

The resin sheet has a durometer hardness (type A) of preferably 0 to 25, more preferably 10 to 25, and even more preferably 10 to 20. A polishing pad provided with a resin sheet having such durometer hardness (type A) is soft and is preferably used for final finishing of a semiconductor device or the like. However, the polishing pad of this embodiment is also related to softness. In particular, it is particularly useful in that the polishing rate at the initial stage of polishing can be quickly stabilized, and fluctuations in the polishing rate can be suppressed. The durometer hardness (type A) is measured at 25 ° C. and measured in accordance with Japanese Industrial Standard (JIS K 6253). More specifically, a sample having a size of 30 mm × 30 mm is measured using a Shore A durometer according to JIS K 7311. In addition, a sample is produced by stacking a plurality of sheets as necessary so that the resin sheet has a total thickness of 4.5 mm or more. And three different places in a sample are measured, and let an average value be the value of durometer hardness (type A). Further, in the measurement method, a sample having a durometer hardness (type A) of 0 may be evaluated with a type C hardness that can measure a softer material. The hardness of type C is a value measured using an Asker rubber hardness meter C type, and is measured in accordance with JIS K7312 for a sample having a dimension of 30 mm × 30 mm. At 25 ° C., a resin sheet having such durometer hardness (type A) can be obtained by a wet film formation method.

The resin sheet preferably has a plurality of bubbles, and the composition thereof is not particularly limited as long as it is a composition that contains the most resin (hereinafter referred to as “matrix resin”) serving as a matrix surrounding the plurality of bubbles. . Specifically, the resin sheet may contain 70 to 100% by mass of the matrix resin with respect to the total amount. The resin sheet contains the matrix resin more preferably 80 to 95% by mass, and still more preferably 85 to 95% by mass, based on the total amount.

From the viewpoint of quickly stabilizing the polishing rate at the initial stage of polishing and / or further enhancing the resistance of the resin sheet to the chemical components contained in the polishing slurry (hereinafter referred to as “chemical resistance”), It is preferable to include a second resin having a bond generated by a reaction between an active hydrogen atom in the first resin having an active hydrogen atom and an isocyanate group derived from a blocked isocyanate compound. Whether or not the resin sheet contains the second resin can also be determined by whether or not it dissolves in N, N-dimethylformamide (DMF). From the same viewpoint, the matrix resin preferably contains 50% by mass or more of the second resin, more preferably 80% by mass or more, and still more preferably 90% by mass or more, based on the total amount of the matrix resin. It is particularly preferable to contain 95% by mass or more.

Although the factor that exhibits the above-described effects by including the second resin in the matrix resin has not been clarified in detail at present, the present inventors consider the factor as follows. However, the factors are not limited to the following.

Conventionally, the matrix resin in the vicinity of the polishing surface has a higher elongation and viscosity, and the state of the polishing surface, etc. gradually changes while repeating the process of being stretched and recovered by the friction described above. It takes a long time until the contributing working surface becomes stable. As a result, when a matrix resin having high elongation and viscosity such as durometer hardness (type A) of 0 to 25 is used, the polishing rate at the initial stage of polishing is difficult to stabilize. On the other hand, the second resin (hereinafter referred to as “resin after bonding”) has the above bond between the molecules of the first resin (hereinafter referred to as “pre-bonding resin”). Increased binding power. As a result, the post-bonding resin is less brittle with reduced elongation and viscosity than the pre-bonded resin, and therefore is easily collapsed by friction with the object to be polished on the polished surface during polishing. That is, the matrix resin containing the post-bonding resin tends to cause permanent distortion in the vicinity of the polished surface, and as a result of the collapse and removal of the portion, the polished surface is smoothed at an early stage. If the polishing surface is smoothed, the surface shape of the polishing pad is unlikely to change, and as a result, the polishing rate at the initial stage of polishing is considered to stabilize early. In addition, smoothing shown here shows smoothing about resin parts other than the opening part which stores and hold | maintains a slurry, The slurry surface etc. are clogged by the opening part, and the whole grinding | polishing surface by the absence of an opening is shown. It is different from smoothing.

Also, by having the above bonds between the molecules of the resin after bonding, the chemical resistance of the resin sheet is improved as a result of a decrease in solubility in chemical components.

As the pre-bonding resin, a polyurethane resin is preferable from the viewpoint of more effectively and reliably achieving the effects of the present invention. The pre-bonding resins are used alone or in combination of two or more.

As the polyurethane resin, for example, a polyisocyanate compound and a polyol compound, or a product obtained by reacting a polyisocyanate compound, a polyol compound and a polyamine compound as main components can be used. The polyurethane resin is preferably a polyurethane resin (polyurethane polyurea resin) containing a polyamine compound from the viewpoint of more effectively achieving the effects of the present invention. The polyisocyanate compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, dibenzyl diisocyanate, diphenyl ether diisocyanate, m-tetramethylxylylene diisocyanate, p-tetra Aromatic diisocyanate compounds such as methylxylylene diisocyanate, aromatic triisocyanate compounds such as triphenylmethane triisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane-4,4′-diisocyanate, hydrogenated xylylene diisocyanate, cyclohexyl-1 Alicyclic diisocyanate compounds such as 1,4-diisocyanate and isophorone diisocyanate, La diisocyanate, aliphatic diisocyanate compounds such as 1,6-hexamethylene diisocyanate (HDI) and the like. Among these, an aromatic diisocyanate compound is preferable from the viewpoint of more effectively and reliably achieving the effects of the present invention, and MDI is preferable as the aromatic diisocyanate compound. These are used singly or in combination of two or more. Furthermore, various modified polyisocyanate compounds such as polyisocyanurate type polyisocyanates having three or more functionalities based on these diisocyanate compounds or biuret type polyisocyanates can also be used.

The polyol compound to be reacted with the polyisocyanate compound has two or more hydroxyl groups in the molecule, and examples thereof include a low molecular weight polyol compound and a high molecular weight polyol compound. Examples of the low molecular weight polyol compound include a diol compound and a triol compound, and more specifically, ethylene glycol, butylene glycol, and 1,4-butanediol. Examples of the high molecular weight polyol compound include polyether polyol compounds such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol (PTMG), a reaction product of ethylene glycol and adipic acid, and butylene glycol and adipic acid. Polyester polyol compounds, polycarbonate polyol compounds, and polycaprolactone polyol compounds. Among these, a polyester polyol compound is preferred from the viewpoint of more effectively and reliably achieving the effects of the present invention. A polyol compound is used individually by 1 type or in combination of 2 or more types.

The polyamine compound to be reacted with the polyisocyanate compound has two or more amino groups in the molecule, and examples thereof include an aliphatic polyamine compound and an aromatic polyamine compound. More specifically, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4′-diamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA), similar to MOCA Examples include polyamine compounds having a structure. Of these, aliphatic polyamines are preferred from the viewpoint of more effectively and reliably achieving the effects of the present invention, and ethylenediamine is preferred as the aliphatic polyamine. The polyamine compound may have a hydroxyl group. Examples of such a compound include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylene. Examples thereof include diamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These are used singly or in combination of two or more.

The blocked isocyanate compound used to obtain the resin after bonding is obtained by reacting one or more isocyanate compounds with one or more blocking agents that are compounds having active hydrogen. In this blocked isonate compound, the blocking agent is dissociated by heating to regenerate the isocyanate group, so that it reacts with the polyurethane resin having an active hydrogen atom to form a bond. The isocyanate compound is preferably a polyvalent isocyanate compound having an average number of isocyanate groups of 2 or more per molecule from the viewpoint of forming many crosslinks with the pre-bonding resin.

As the polyvalent isocyanate compound used for the blocked isocyanate compound, the resin after bonding has no aromatic ring from the viewpoint of exhibiting low hardness without being too hard compared with the resin before bonding, that is, the aromatic polyvalent isocyanate compound. Polyisocyanate compounds other than those are preferred, aliphatic polyisocyanate compounds and alicyclic polyisocyanate compounds are preferred, and aliphatic polyisocyanate compounds are more preferred.

As the polyvalent isocyanate compound, a diisocyanate compound is preferable from the viewpoint of ensuring the flexibility of the resin sheet. Examples of such diisocyanate compounds include TDI, MDI, xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, dibenzyl diisocyanate, diphenyl ether diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethyl. Aromatic diisocyanate compounds such as xylylene diisocyanate, aromatic triisocyanate compounds such as triphenylmethane triisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane-4,4′-diisocyanate, hydrogenated xylylene diisocyanate, cyclohexyl-1, Alicyclic diisocyanate compounds such as 4-diisocyanate and isophorone diisocyanate, 1,4-tetramethylene diisocyanate Over DOO, aliphatic diisocyanate compounds such as HDI and the like. Among these, an aliphatic diisocyanate compound and an alicyclic diisocyanate compound are preferable, an aliphatic diisocyanate compound is more preferable, and HDI is still more preferable from the viewpoint of more effectively and reliably achieving the effects of the present invention. These are used singly or in combination of two or more.

Furthermore, various modified polyvalent isocyanate compounds such as tri- or higher functional adduct type polyisocyanate, isocyanurate type polyisocyanate or biuret type polyisocyanate by a modified polyvalent isocyanate compound exhibiting elasticity can also be used. Of these, adduct-type polyisocyanates and isocyanurate-type polyisocyanates are preferred, and adduct-type polyisocyanates are more preferred from the viewpoint of more effectively and reliably achieving the effects of the present invention. From the same viewpoint, adduct type HDI is preferable as the adduct type polyisocyanate, and isocyanurate type HDI is preferable as the isocyanurate type polyisocyanate. When the isocyanate group content of these modified polyvalent isocyanate compounds (hereinafter referred to as “NCO%”) is 13% or less, the number of carbon atoms in the chain between the isocyanate groups in the polyisocyanate molecule is large, and the isocyanate group Since the distance between them becomes relatively long, the distance between the bonds (between the crosslinking points) becomes long when the plurality of isocyanate groups and the plurality of active hydrogen atoms of the polyurethane resin are bonded. This maintains the flexibility of the pre-bonding resin and does not have a regular cross-linked structure, so the plastically deformed resin does not partially exhibit rubber-like recovery characteristics, and there is local permanent distortion on the polished surface. It is thought that it can occur. As a result, it is presumed that the polishing rate at the initial stage of polishing can be quickly stabilized, the working surface contributing to polishing is increased, and the polishing rate can be improved and the increased polishing rate can be maintained. From the same viewpoint, the upper limit value of NCO% is more preferably 10%, and further preferably 8%. The lower limit value of NCO% is preferably 3% by mass, more preferably 5% by mass. When NCO% is not less than the above lower limit, a crosslinked structure can be more sufficiently formed. NCO% is expressed by the following formula.
NCO% = (42 × NCO group number) / Molecular weight of isocyanate compound

Also, as a polyvalent isocyanate compound, a lactone is subjected to a ring-opening addition polymerization reaction with a polyol compound to form a lactone-modified product (polylactone polyol ester), and the above-mentioned polyvalent isocyanate compound is added to the lactone-modified polyvalent isocyanate compound. May be used. That is, the lactone-modified polyvalent isocyanate compound corresponds to a compound in which a ring-opening polymer of lactone is interposed by an ester bond between the hydroxyl group of the polyol compound and the isocyanate group of the polyvalent isocyanate compound. Such a lactone-modified polyvalent isocyanate compound is a soft resin sheet having a durometer hardness (type A) of 0 to 25 due to molecular flexibility due to an ester bond, and the resin sheet. Is preferable from the viewpoint of easily satisfying Rsk in the above range. From the same point of view, the modified polyisocyanate compound is a modified adduct, that is, the lactone ring-opening polymer is ester-bonded between the hydroxyl group of the polyol compound and the isocyanate group of the polyvalent isocyanate compound in the adduct-type polyisocyanate. It is more preferable that they are interposed. The addition polymerization of lactone to polyol can be carried out using an organic compound such as tin, lead or manganese, a metal chelate or the like as a catalyst.

Examples of the lactone include γ-lactone, δ-lactone, and ε-lactone, and among them, ε-caprolactone is preferable. As the polyol, a polyhydric alcohol having a relatively low molecular weight which is usually used for forming an adduct can be used. For example, ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, Diols such as 6-hexanediol, and triols such as glycerin, trimethylolpropane and trimethylolbutane.

The blocking agent for blocking the isocyanate group of the polyvalent isocyanate compound is not particularly limited as long as it is a generally known compound having an active hydrogen atom. Examples of the blocking agent include alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, t-butanol and 2-ethylhexanol, ketoximes such as methyl ethyl ketoxime, phenol, and ε-caprolactam. , Ethyl acetoacetate and diethyl malonate. These are used singly or in combination of two or more. Considering the dissociation property of the blocking agent, methyl ethyl ketoxime and ε-caprolactam are preferable as the blocking agent, and methyl ethyl ketoxime is more preferable.

From the viewpoint of promptly stabilizing the polishing rate at the initial stage of polishing and / or further improving chemical resistance against chemical components contained in the polishing slurry, the post-bonding resin is composed of an active hydrogen atom and a blocked isocyanate. The bond produced by the reaction with the isocyanate group derived from the compound is preferably 2.0 parts by mass to 15.0 parts by mass in terms of the blocked isocyanate compound, based on the resin before bonding (100 parts by mass), preferably 3.0 parts by mass. Part to 10.0 parts by weight, more preferably 5.0 parts to 7.5 parts by weight. By setting it as 2.0 mass parts or more in conversion of a block isocyanate compound, it will become more excellent in chemical resistance. By setting it as 15.0 mass parts or less in conversion of a block isocyanate compound, since the isocyanate compound which does not couple | bonds decreases and it can further suppress that a resin sheet becomes too brittle, stability of a polishing rate improves.

The matrix resin may include a resin contained in a resin sheet in a known polishing pad, represented by, for example, a polyurethane resin, a polysulfone resin, and a polyimide resin, in addition to the above-described post-bonding resin. These are used singly or in combination of two or more. Examples of the polyurethane resin include those described above.

Polysulfone resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Udel (trade name manufactured by Solvay Advanced Polymers Co., Ltd.). Moreover, a polyimide resin may be synthesize | combined by a conventional method and a commercial item may be obtained. Examples of commercially available products include Aurum (trade name, manufactured by Mitsui Chemicals, Inc.).

The resin sheet may contain, in addition to the matrix resin, one or more of materials usually used for a resin sheet for a polishing pad, for example, a pigment such as carbon black, a hydrophilic additive and a hydrophobic additive. These arbitrarily used materials may be used to control the size and number of bubbles in the resin sheet. Furthermore, various materials such as a solvent used in the manufacturing process of the resin sheet may remain in the resin sheet as long as the problem of the present invention is not impaired.

The 100% modulus at 25 ° C. of the resin contained in the resin sheet is 3.0 to 10.0 MPa from the viewpoint of more effectively and surely achieving the operational effects of the above-described embodiment and making a soft resin sheet. Preferably, it is 4.0 MPa or more, more preferably 8.0 MPa or less. The 100% modulus is a value obtained by dividing the load applied when the non-foamed resin sheet using the same material as the resin sheet is extended by 100%, that is, when the resin sheet is extended to twice the original length, by the cross-sectional area. .

The polishing pad of the present embodiment may have the same configuration as that of a conventional polishing pad, except that the polishing pad includes the resin sheet. For example, the polishing pad of this embodiment may include the resin sheet and a double-sided tape that is bonded and laminated to the resin sheet. The double-sided tape is for attaching a polishing pad to a polishing machine. For example, the double-sided tape has a flexible film substrate such as a polyethylene terephthalate film, and an acrylic adhesive or the like is provided on both surfaces of the substrate. Each adhesive layer is formed. The double-sided tape is bonded to a resin sheet with an adhesive layer on one side of the substrate, and the adhesive layer on the other side is covered with release paper. The base material of the double-sided tape also serves as the base material of the polishing pad.

Next, an example of a method for manufacturing the above-described polishing pad of this embodiment will be described. The manufacturing method of the polishing pad employs a so-called wet film-forming method, a step of coagulating and regenerating the pre-bonding resin in the resin solution containing the pre-bonding resin, the blocked isocyanate compound and the solvent (coagulation regenerating step); And a step (bonding step) of obtaining a resin after bonding by reacting an active hydrogen atom of the pre-bonding resin with an isocyanate group derived from a blocked isocyanate compound. The polishing pad manufacturing method further includes a resin solution preparation step for preparing the resin solution, a coating step for applying the resin solution to the film-forming substrate before the coagulation regeneration step, and a resin obtained through the coagulation regeneration step. At least one of a solvent removal step of removing the solvent from the substrate, a grinding step of grinding the polished surface of the resin sheet, a groove forming step of forming a groove on the polished surface of the resin sheet, and a bonding step of bonding a double-sided tape to the resin sheet It is preferable to have two steps.

In the resin solution preparation step, a resin solution containing a pre-bonding resin, a blocked isocyanate compound, and a solvent is prepared. A preparation method is not specifically limited, For example, a resin solution can be obtained by mixing each raw material which should be contained in a resin solution, and fully stirring. The pre-bonding resin and the blocked isocyanate compound may be those described above. Further, the content ratio of the blocked isocyanate compound in the resin solution is such that the post-bonding resin has a bond generated by a reaction between the active hydrogen atom of the pre-bonding resin and the isocyanate group derived from the blocked isocyanate compound in the above-described ratio. Is preferable.

Examples of the solvent include DMF, N, N-dimethylacetamide (DMAc), tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), and acetone. These are used singly or in combination of two or more.

From the viewpoint of ensuring the polishing ability of the resin sheet and more sufficiently holding the polishing slurry in the bubbles of the resin sheet, the resin solution has a viscosity measured at 25 ° C. using a B-type rotational viscometer of 3 to 30 Pa · It is preferably in the range of s, more preferably in the range of 5 to 20 Pa · s. From the viewpoint of obtaining a resin solution having such a numerical value range of viscosity, the content of the pre-bonding resin in the resin solution is preferably in the range of 10 to 30% by mass, and in the range of 15 to 25% by mass. More preferred. Since the viscosity of the resin solution also depends on the type and molecular weight of the matrix resin to be used, the concentration of the pre-bonding resin in the resin solution may be set by comprehensively considering these.

The resin solution may optionally contain additives in addition to the above raw materials. Examples of optional additives include pigments such as carbon black, hydrophilic activators that promote foaming, and hydrophobic activators that stabilize resin coagulation regeneration.

In the coating process, the resin solution is coated on the film forming substrate. As a coating method, for example, a coating device such as a knife coater may be used at room temperature to apply the sheet-like film-forming substrate substantially uniformly in a sheet shape. At this time, the application thickness (application amount) of the resin solution can be adjusted by adjusting the gap (clearance) between the knife coater or the like and the film forming substrate. Examples of the material for the film forming substrate include a resin film such as a PET film, a fabric, and a nonwoven fabric. Among these, a resin film such as a PET film that hardly penetrates the resin solution is preferable.

In the coagulation regeneration process, the coating film of the resin solution applied to the film-forming substrate is mainly composed of a poor solvent (for example, water for polyurethane resin) with respect to the resin contained in the resin solution such as the resin before bonding. Guide continuously into the coagulation liquid. In order to adjust the regeneration speed of the resin contained in the resin solution, an organic solvent such as a polar solvent other than the solvent in the resin solution may be added to the coagulation liquid. The temperature of the coagulation liquid is not particularly limited as long as the resin in the resin solution can be coagulated. When the resin is a polyurethane resin, it may be, for example, 5 to 80 ° C., but preferably 15 ~ 20 ° C. In the coagulating liquid, first, a film is formed at the interface between the coating film of the resin solution and the coagulating liquid, and a layer having innumerable fine bubbles called a skin layer is formed in the resin immediately adjacent to the film. Thereafter, due to the cooperative phenomenon of the diffusion of the solvent contained in the resin solution into the coagulation liquid and the penetration of the poor solvent into the resin, the regeneration of the resin having an open cell structure preferably proceeds, which is called a foamed resin region A region is formed. At this time, if the substrate for film formation is difficult to permeate the coagulation liquid (for example, a PET film), substitution of the solvent in the resin solution with the poor solvent occurs preferentially on the skin layer side, and the foamed resin region Larger bubbles tend to be formed on the side than on the skin layer side. At this time, the blocked isocyanate compound is mixed unreacted in the regenerated resin. Thus, a sheet-like resin (hereinafter also referred to as “film-forming resin”) is formed on the film-forming substrate.

Next, in the solvent removal step, the solvent remaining in the film-forming resin obtained through the coagulation regeneration step is removed. For removing the solvent, a conventionally known water washing treatment can be used.

Next, in the bonding step, the post-bonding resin is obtained by reacting the active hydrogen atom of the pre-bonding resin in the film-forming resin after removal of the solvent with the isocyanate group derived from the blocked isocyanate compound. At this time, the film-forming resin is preferably subjected to a heat treatment in a temperature range of 145 to 180 ° C., more preferably in a temperature range of 150 to 165 ° C., and preferably for 15 to 20 minutes. In the heat treatment, for example, the film-forming resin is continuously passed through a heated atmosphere. By heating, the blocking agent is dissociated from the blocked isocyanate compound contained in the film-forming resin, and a reactive isocyanate group is regenerated. This isocyanate group reacts with an active hydrogen atom of a resin before bonding, for example, when the resin before bonding is a polyurethane resin, and reacts with an active hydrogen atom constituting a urethane bond or a urea bond to obtain a resin after bonding. . Further, the resin dries with this heating. The resin sheet containing the post-bonding resin thus obtained may be cut to an appropriate length and laid flat.

In the grinding process, a grinding process is performed on the skin layer side of the resin sheet to make the thickness of the resin sheet uniform by buffing. That is, the substantially flat surface of the pressure welding jig is pressed against the surface of the resin sheet opposite to the skin layer, and buffing is performed on the skin layer side. Thereby, a part of air bubbles are opened in the polishing surface, and the thickness of the resin sheet is made uniform. Subsequently, in the groove forming step, the groove is formed by embossing or cutting the surface of the resin sheet on the skin layer side (the surface subjected to the grinding process).

In the bonding process, a double-sided tape is bonded to the resin sheet to obtain an abrasive sheet. At this time, the surface of the resin sheet on the foamed resin region side and the adhesive layer on one side of the double-sided tape are bonded together. The pressure-sensitive adhesive of the pressure-sensitive adhesive layer may be a conventionally known one, and may be a pressure-sensitive type or a heat-sensitive type.

The polishing method using the polishing pad of the present embodiment includes a step of polishing an object to be polished using the obtained polishing pad. One specific example will be described below. First, an object to be polished is held on a holding surface plate of a single-side polishing machine. Next, the polishing pad is mounted on the polishing surface plate disposed so as to face the holding surface plate. When the polishing pad is mounted on the polishing surface plate, if the polishing pad includes release paper, the release paper is removed, and the exposed double-sided tape is brought into contact with the polishing surface plate and pressed. In addition, when the polishing pad is not provided with a double-sided tape, it is also possible to attach or apply an adhesive or an adhesive to the polishing pad and then attach it to the polishing surface plate. A polishing slurry containing chemical components such as abrasives (polishing particles; for example, SiO ₂ , CeO ₂ ) and an oxidant represented by hydrogen peroxide is circulated and supplied between the object to be polished and the polishing pad. The object to be polished is polished by CMP by rotating the polishing surface plate or holding surface plate while pressing the object to be polished toward the polishing pad with a predetermined polishing pressure.

The polishing pad of this embodiment is particularly suitably used for finish polishing of magnetic disk substrates, semiconductor devices, bare silicon, and glass substrates for liquid crystal displays. However, the use of the polishing pad of this embodiment is not limited to them.

As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said this embodiment. The present invention can be variously modified without departing from the gist thereof.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
First, as a polyurethane resin, a polyester polyol compound-MDI-ethylenediamine-based polyurethane resin (polyurethane polyurea resin) having a 100% modulus at 25 ° C. of 6.0 MPa was prepared. Also, a blocked isocyanate compound (solid content: 80%, NCO%: about 6.0%) prepared by blocking an HDI adduct with methyl ethyl ketoxime was prepared as a blocked isocyanate compound. A block isocyanate compound solution is mixed with a solution composed of 30 parts by mass of polyurethane resin and 70 parts by mass of DMF so as to have a ratio of 2.0 parts by mass (5.3 parts by mass with respect to 100 parts by mass of polyurethane resin). Further, 31.8 parts by mass of DMF was added thereto and mixed and stirred to obtain a resin solution. The viscosity at 25 ° C. was measured with a B-type rotational viscometer (trade name “TVB-10 type” manufactured by Toki Sangyo Co., Ltd.) and found to be 11.0 Pa · s.

Next, a strip-like PET film was prepared as a film forming substrate. The resin solution was applied onto the coating surface of the film-forming substrate using a knife coater to obtain a coating film. Next, the obtained coating film was immersed in a room temperature coagulation bath made of water as a coagulation liquid, and the resin was coagulated and regenerated to obtain a film forming resin. The film-forming resin was taken out from the coagulation bath, peeled off from the film-forming substrate, and then immersed in a room temperature cleaning solution (desolvent bath) made of water to remove DMF.

Then, in the bonding step, using a heating device (manufactured by Ichikin Kogyo Co., Ltd., model number “VIC-0326-1680”), after drying moisture at 120 ° C., the dried film is heated and crosslinked at 150 ° C. (bonding). Thus, a resin sheet was obtained. Next, the surface of the resin layer after the bonding step was buffed to obtain a resin sheet having a thickness of 0.80 mm and a durometer hardness (type A) of 19. A base material was affixed to the non-buffed side of the resin sheet, and after embossing, it was affixed to a double-sided tape provided with release paper on one side to obtain an abrasive sheet.

[Method for measuring surface properties]
A polishing test which is a “predetermined polishing test” was performed under the following conditions.
-Polishing machine: Model number "F-REX300" manufactured by Ebara Manufacturing Co., Ltd.
Polishing head: manufactured by Ebara Manufacturing Co., Ltd., model number “GII”
・ Polishing slurry: manufactured by Cabot, model number “SS-25”, diluted 20 times ・ Substance to be polished: 300 mmφ silicon wafer with tetraethylorthosilicate (TEOS) film ・ Polishing pad diameter: 740 mmφ
・ Pad break-in conditions: 100 N × 10 minutes, diamond dresser # 100 (pellet type) rotation speed 20 rpm, surface plate rotation speed 80 rpm, ultrapure water supply amount 500 mL / min ・ Polishing conditions: surface plate rotation speed 70 rpm, polishing head rotation 71 rpm, polishing slurry flow rate 200 mL / min, polishing time 60 minutes (10 minutes × 6 wafers), polishing pressure 2.5 psi (1.7 × 10 ⁴ Pa)

A sample obtained by cutting the resin sheet on the polishing pad after performing the above-mentioned “predetermined polishing test” into a 5 mm × 5 mm rectangle is placed on a sample holder of a 3D laser microscope (model number “VK8700”) manufactured by Keyence. It was installed so as not to occur. The sample was observed at a magnification of 200 times with the 3D laser microscope. The measurement range is set to a range of 75 μm × 75 μm with no holes in 1.0 mm × 1.4 mm, and by setting the measurement condition to “filter; off”, Rsk, height distribution variation coefficient for each measurement point, Ra values were obtained. The measurement points were randomly selected 20 points, and the arithmetic mean of them was Rsk, height distribution variation coefficient, and Ra of the sample. In addition, when the area which is not opened is smaller than 75 micrometers x 75 micrometers, it is good also considering a measurement range as a range of 50 micrometers x 50 micrometers. The results are shown in Table 1.

(Example 2)
A polishing pad was prepared in the same manner as in Example 1 except that a polyester polyol compound-MDI-ethylenediamine-based polyurethane resin (polyurethane polyurea resin) having a 100% modulus at 25 ° C. of 3.0 MPa was used as the polyurethane resin. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 12.4 Pa · s. The durometer hardness (type A) of the resin sheet was 0 (0.3 in hardness (type C)).

Example 3
A polishing pad was prepared in the same manner as in Example 1 except that a polyester polyol compound-MDI-ethylenediamine-based polyurethane resin (polyurethane polyurea resin) having a 100% modulus of 9.0 MPa at 25 ° C. was used as the polyurethane resin. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 10.2 Pa · s. Further, the durometer hardness (type A) of the resin sheet was 22.

Example 4
A polishing pad was prepared in the same manner as in Example 1 except that the blocked isocyanate compound was mixed at a ratio of 5.0 parts by mass (13.3 parts by mass with respect to 100 parts by mass of the polyurethane resin). Was measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 11.9 Pa · s. The durometer hardness (type A) of the resin sheet was 21.

(Example 5)
Polishing pad in the same manner as in Example 1 except that a blocked isocyanate compound obtained by blocking an HDI isocyanurate form with methyl ethyl ketoxime (solid content: 80%, NCO%: about 12.5%) was used as the blocked isocyanate compound. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 10.9 Pa · s. Moreover, the durometer hardness (type A) of the resin sheet was 20.

(Comparative Example 1)
A polishing pad was prepared in the same manner as in Example 1 except that the blocked isocyanate compound was not used, and the surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 11.6 Pa · s. Further, the durometer hardness (type A) of the resin sheet was 19.

(Comparative Example 2)
A polishing pad was prepared in the same manner as in Example 1 except that a polyester polyol compound-MDI-ethylenediamine-based polyurethane resin (polyurethane polyurea resin) having a 100% modulus at 25 ° C. of 2.0 MPa was used as the polyurethane resin. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 12.7 Pa · s. Further, the durometer hardness (type A) of the resin sheet was 0 (0.5 (hardness (type C)).

(Comparative Example 3)
A polishing pad was prepared in the same manner as in Example 1 except that a polyester polyol compound-MDI-ethylenediamine-based polyurethane resin (polyurethane polyurea resin) having a 100% modulus at 25 ° C. of 15.0 MPa was used as the polyurethane resin. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 11.0 Pa · s. Moreover, the durometer hardness (type A) of the resin sheet was 26.

(Comparative Example 4)
A polishing pad was prepared in the same manner as in Example 1 except that the blocked isocyanate compound was mixed at a ratio of 7.0 parts by mass (18.6 parts by mass with respect to 100 parts by mass of the polyurethane resin). Was measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 12.2 Pa · s. Further, the durometer hardness (type A) of the resin sheet was 22.

(Comparative Example 5)
A polishing pad as in Example 1 except that a blocked isocyanate compound obtained by blocking an HDI adduct with methyl ethyl ketoxime (solid content: 80%, NCO%: about 15.5%) was used as the blocked isocyanate compound. The surface properties were measured. The results are shown in Table 1. When the viscosity of the resin solution was measured in the same manner as in Example 1, it was 10.8 Pa · s. The durometer hardness (type A) of the resin sheet was 21.

[Polishing test]
A polishing test was performed using the polishing pad under the following conditions.
-Polishing machine: Model number "F-REX300" manufactured by Ebara Manufacturing Co., Ltd.
Polishing head: manufactured by Ebara Manufacturing Co., Ltd., model number “GII”
Polishing slurry: Planar, model number “ER8176C”, 2-fold dilution, hydrogen peroxide concentration 0.8 mass%
・ Polished object: 300 mmφ silicon wafer with silica (TEOS) film ・ Polishing pad diameter: 740 mmφ
・ Dresser: 3M diamond dresser, model number “A188”
・ Pad break-in condition: 30 N × 30 minutes, dresser rotation speed 54 rpm, surface plate rotation speed 80 rpm, ultrapure water supply amount 500 mL / min ・ conditioning: Ex-situ 30 N, 4 scans, 16 seconds ・ Polishing condition: fixed Plate rotation speed 70 rpm, polishing head rotation speed 71 rpm, polishing slurry flow rate 200 mL / min, polishing time 1 minute (per wafer), polishing pressure 2.5 psi (1.7 × 10 ⁴ Pa)

<Polishing rate>
For the TEOS film on the wafer before and after the polishing test, the polishing rate (レート / min) was determined by dividing the thickness polished at each point by the polishing time from the thickness measurement results at 121 locations. The thickness was measured in the DBS mode of an optical film thickness measuring instrument (manufactured by KLA Tencor, model number “ASET-F5x”).

<Number of startup processing>
Whether or not the polishing rate at the initial stage of polishing was quickly stabilized was evaluated as follows. That is, the polishing rate with respect to the number of wafers to be polished was tracked, and the number of polishing processes in which the increase in the polishing rate as a trend was not observed was defined as the “number of startup processes”. It means that the smaller the “number of start-up treatments”, the faster the polishing rate at the initial stage of polishing is stabilized. The results are shown in Table 1.

<Evaluation of polishing rate stability and polishing uniformity>
Each polishing rate from 1 to 600 wafers is determined, and the maximum, minimum, average, and standard deviation of the polishing rate for 100, 300, and 600 processed wafers are calculated. The polishing rate stability and polishing uniformity were evaluated by the formula.
Polishing rate stability (%) = (maximum polishing rate−minimum polishing rate) / average polishing rate × 100
Polishing uniformity (%) = (polishing rate standard deviation / polishing rate average value) × 100
The polishing rate stability has a lower numerical value, and the smaller the variation due to the number of processed sheets, the higher the polishing stability. Further, the polishing uniformity indicates that the lower the numerical value, the less the polishing unevenness and the more uniformly the wafer surface is polished. The results are shown in Table 1.

<Evaluation of chemical resistance>
The chemical resistance was judged by the presence or absence of solubility in DMF with high polarity. When not dissolved in DMF, it can be said that the chemical resistance is excellent.

First, a resin sheet was cut into a 5 mm × 30 mm rectangle to obtain a sample. Next, the sample was put into a test tube containing 30 mL of DMF. The test tube in which the sample was introduced was stirred for 1 minute, then allowed to stand for 10 minutes, and further stirred for 2 minutes. Next, after allowing the test tube to stand for 5 minutes, the sample contained in the test tube is filtered together with DMF using a 50 mesh (mesh opening 300 μm) test sieve, and whether or not solid matter remains on the sieve is determined. It was confirmed visually. When the solid substance remained, it was evaluated as “A” because it was excellent in chemical resistance, and when the solid substance did not remain, it was evaluated as “B” because it was not excellent in chemical resistance. The results are shown in Table 1.

Further, photographs of the cross sections of the resin sheets of Example 1 and Comparative Example 1 observed with an electron microscope are shown in FIGS. 2 and 3, respectively. In the figure, the boundary with the upper black portion indicates the surface of the resin sheet. From the comparison of these photographs, the resin sheet according to the example has less surface irregularities than the resin sheet according to the comparative example. It was found that the flatness was high.

When the example and the comparative example were compared, it was found that the fluctuation of the polishing rate and the polishing uniformity tended to be smaller in the example even when the number of processed wafers was increased. Further, regarding the number of rising treatments, although a conventional resin having a high modulus tends to rise quickly, in Examples 1 and 3, the 100% modulus and durometer hardness (type A) are lower than those in Comparative Example 3. As a result, it was found that the number of rising treatments was small, and the polishing rate at the initial stage of polishing was quickly stabilized. Further, when Example 2 and Comparative Example 2 are compared with each other, both are 100% modulus and durometer hardness (type A), which is a fairly soft polishing pad, but Example 2 is the number of startup treatments. Both the polishing rate stability and the polishing uniformity were excellent.

According to the present invention, it is possible to provide a polishing pad that can quickly stabilize the polishing rate at the initial stage of polishing and that suppresses fluctuations in the polishing rate, and a method for manufacturing the same. There is industrial applicability to finish polishing of semiconductor devices, bare silicon, and glass substrates for liquid crystal displays.

Claims

A polishing pad comprising a resin sheet,
The polished surface of the sheet after undergoing a predetermined polishing test has a skewness Rsk of a roughness curve of −2.00 or more and −0.20 or less, and 0.5% or more and 2.5% or less. A polishing pad having a coefficient of variation of height distribution.
The polishing pad according to claim 1, wherein the sheet has a durometer hardness (type A) of 0 to 25.
The polishing pad according to claim 1 or 2, wherein the sheet is formed by wet film formation.
The polishing pad according to any one of claims 1 to 3, wherein the resin contained in the sheet has a 100% modulus of 3.0 MPa to 10.0 MPa.
The resin includes a second resin having a bond generated by a reaction between the active hydrogen atom in the first resin having an active hydrogen atom and an isocyanate group derived from a blocked isocyanate compound, and the bond is included in the first resin. The polishing pad according to any one of claims 1 to 4, wherein the polishing pad has 2.0 to 15.0 parts by mass in terms of the blocked isocyanate compound with respect to 100 parts by mass.
The polishing pad according to claim 5, wherein the blocked isocyanate compound is obtained by blocking one or more compounds selected from the group consisting of polyvalent isocyanate compounds other than aromatic polyvalent isocyanate compounds with a blocking agent.
The polishing pad according to claim 5 or 6, wherein the first resin is a polyurethane resin.
A method for producing a polishing pad according to any one of claims 1 to 7,
The sheet provided in the polishing pad contains a second resin,
A step of coagulating and regenerating the first resin in a resin solution containing a first resin having an active hydrogen atom, a blocked isocyanate compound, and a solvent;
Reacting the active hydrogen atom of the first resin with the isocyanate group derived from the blocked isocyanate compound to obtain the second resin,
In the second resin, a bond generated by the reaction between the active hydrogen atom and the isocyanate group is 2.0 parts by mass to 15.0 parts in terms of the blocked isocyanate compound with respect to 100 parts by mass of the first resin. The manufacturing method which has a mass part.