TW201942175A - Polishing pad, polishing pad production method, and method for polishing surface of optical material or semiconductor material - Google Patents

Abstract

The purpose of the present invention is to provide a polishing pad that minimizes defects in a polished object, is capable of achieving a flat topography, and exhibits excellent defect performance and topography performance. Provided is a polishing pad having a polishing layer that contains a polyurethane resin, wherein: the polyurethane resin is a cured product of a curable resin composition comprising an isocyanate-terminated urethane prepolymer and a curing agent; the isocyanate-terminated urethane prepolymer is a reaction product between a polyisocyanate component and a polyol component containing a glycol having a molecular weight of 50-300; and the content of the glycol is more than 0 wt% but less than 5 wt% with respect to the total amount of the isocyanate-terminated urethane prepolymer.

Description

Polishing pad, manufacturing method of polishing pad, and surface polishing method of optical material or semiconductor material

The invention relates to a polishing pad, a manufacturing method of the polishing pad, and a surface polishing method of an optical material or a semiconductor material. The polishing pad of the present invention is used for polishing optical materials, semiconductor wafers, semiconductor devices, substrates for hard disks, and the like, and is particularly suitable for polishing devices having an oxide layer and a metal layer formed on a semiconductor wafer.

Optical materials, semiconductor wafers, hard disk substrates, glass substrates for liquid crystals, and semiconductor devices require very precise flatness. In the polishing of semiconductor devices, along with the miniaturization and high density of integrated circuits in recent years, suppression of defects (defects) such as scratches (scratches) on the object to be polished or flat morphology (depression, Suppression of abrasion, etc.), and increasingly stricter levels are required. In order to smooth the surface of such various materials, a hard polishing pad is usually used.

Currently, most hard polishing pads are manufactured by the so-called prepolymer method, that is, polyamines or polyols as hardeners, foaming agents, catalysts, etc. as additives, and polyol components and isocyanate components. The urethane prepolymers of the reactants are mixed to produce a polyurethane composition, and the polyurethane composition is hardened. Most urethane prepolymers are made from isocyanate components such as toluene diisocyanate (TDI) or diphenylmethane diisocyanate (MDI), polyoxytetramethylene glycol (PTMG), or polypropylene glycol (PPG). Manufactured from high molecular weight polyols such as low molecular weight polyols such as diethylene glycol (DEG). In addition, in the urethane prepolymer for polishing pads, it is generally used: diethylene glycol (DEG) is used at a relatively high content of approximately 5 to 10% by weight relative to the entire urethane prepolymer. ) As a low molecular weight polyol, or only using diethylene glycol (DEG) as a low molecular weight polyol.

[Problems to be solved by the invention]

However, the inventors of the present inventors have studied and found that, as shown in the following comparative examples, diethylene glycol (DEG) is contained in a relatively high content of 5% by weight relative to the entire urethane prepolymer. Diol (DEG) is a polishing pad formed of an isocyanate-terminated urethane prepolymer of a low molecular weight diol, or an isocyanate-terminated amine group containing only diethylene glycol (DEG) as a low molecular weight diol The polishing pad formed by the formate prepolymer may cause defects in the object to be polished, so that a flat morphology cannot be obtained.

As described above, there is a demand for a polishing pad that can suppress defects in an object to be polished and achieve a flat topography, and has excellent defect performance and topography performance.

An object of the present invention is to provide a polishing pad, a manufacturing method of the polishing pad, and a surface polishing method of an optical material or a semiconductor material. The polishing pad can suppress defects in the object to be polished and realize a flat topography, and the defect performance and topography Excellent performance.
[Technical means to solve the problem]

The present inventors conducted diligent research in order to solve the above-mentioned problems, and as a result, found that polyoxyalkylene glycols such as diethylene glycol (DEG), which is used as a component of the isocyanate-terminated urethane prepolymer, have been found. The content is suppressed to a low level, or a specific alkylene glycol is used instead of diethylene glycol (DEG) as a component of the isocyanate-terminated urethane prepolymer, thereby solving the above problems, thereby completing the present invention. invention. Specific aspects of the invention are described below.
In addition, in this specification, when "~" is used to indicate a numerical range, the range includes numerical values at both ends.

[1] A polishing pad having a polishing layer containing a urethane resin, and the urethane resin is a hardened product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a hardener, and the isocyanate-terminated The urethane prepolymer is a reaction product of a polyol component and a polyisocyanate component of a diol having a molecular weight of 50 to 300, and the content of the diol is relative to the entire isocyanate-terminated urethane prepolymer. More than 0% by weight and less than 5% by weight.
[2] The polishing pad according to [1], wherein the diol is polyoxyalkylene glycol.
[3] The polishing pad according to [2], wherein the polyoxyalkylene glycol is diethylene glycol.
[4] The polishing pad according to [1], wherein the diol is an alkylene glycol.
[5] The polishing pad according to [4], wherein the alkylene glycol-based linear compound has a hydroxyl group at a molecular terminal.
[6] The polishing pad according to [5], wherein the alkylene glycol is 1,4-butanediol.
[7] The polishing pad according to any one of [1] to [6], wherein the NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is less than 500.
[8] The polishing pad according to any one of [1] to [7], wherein the polyisocyanate component includes toluene diisocyanate.
[9] The polishing pad according to any one of [1] to [8], wherein the polyol component further includes polyoxytetramethylene glycol.
[10] The polishing pad according to any one of [1] to [9], wherein the hardener comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.
[11] The polishing pad according to any one of [1] to [10], wherein the curable resin composition further contains fine hollow spheres.
[12] A method, which is a method for manufacturing a polishing pad according to any one of [1] to [11], and the method includes a step of forming the polishing layer.
[13] A method which is a surface polishing method of an optical material or a semiconductor material, and the above method uses a polishing pad according to any one of [1] to [11].

[1 '] A polishing pad having a polishing layer containing a polyurethane resin, and the polyurethane resin is a hardened product of a hardening resin composition containing an isocyanate-terminated urethane prepolymer and a hardener, and the isocyanate seal The urethane-terminated prepolymer is a reaction product of a polyol component and a polyisocyanate component of a polyoxyalkylene glycol having a molecular weight of 50 to 300, and the content of the polyoxyalkylene glycol relative to the isocyanate The total amount of the blocked urethane prepolymer is more than 0% by weight and less than 5% by weight.
[2 '] The polishing pad according to [1'], wherein the polyoxyalkylene glycol is diethylene glycol.
[3 '] The polishing pad according to [1'] or [2 '], wherein the NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is less than 500.
[4 '] The polishing pad according to any one of [1'] to [3 '], wherein the polyisocyanate component includes toluene diisocyanate.
[5 '] The polishing pad according to any one of [1'] to [4 '], wherein the polyol component further includes polyoxytetramethylene glycol.
[6 '] The polishing pad according to any one of [1'] to [5 '], wherein the hardener comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.
[7 '] The polishing pad according to any one of [1'] to [6 '], wherein the curable resin composition further contains fine hollow spheres.
[8 '] A method for manufacturing a polishing pad according to any one of [1'] to [7 '], and the method includes a step of forming the polishing layer.
[9 '] A method which is a surface polishing method of an optical material or a semiconductor material, and the above method uses a polishing pad according to any one of [1'] to [7 '].

[1 ''] A polishing pad having a polishing layer containing a polyurethane resin, and the polyurethane resin is a hardened product of a hardening resin composition containing an isocyanate-terminated urethane prepolymer and a hardener, and the isocyanate The blocked urethane prepolymer includes a reaction product of a polyol component of a polyalkylene glycol having a molecular weight of 50 to 300 and a polyisocyanate component, and the content of the polyalkylene glycol relative to the isocyanate blocked amine The urethane prepolymer as a whole exceeds 0% by weight and less than 5% by weight.
[2 "] The polishing pad according to [1"], wherein the alkylene glycol-based linear compound having a hydroxyl group at a molecular terminal.
[3 "] The polishing pad according to [2"], wherein the alkylene glycol is 1,4-butanediol.
[4 ''] The polishing pad according to any one of [1 ''] to [3 ''], wherein the polyisocyanate component includes toluene diisocyanate.
[5 "] The polishing pad according to any one of [1"] to [4 "], wherein the polyol component further includes polyoxytetramethylene glycol.
[6 ''] The polishing pad according to any one of [1 ''] to [5 ''], wherein the hardener comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane.
[7 "] The polishing pad according to any one of [1"] to [6 "], wherein the curable resin composition further includes fine hollow spheres.
[8 "] A method, which is a method for manufacturing a polishing pad according to any one of [1"] to [7 "], and the method includes a step of forming the polishing layer.
[9 ''] A method which is a surface polishing method such as an optical material or a semiconductor material, and the above method uses a polishing pad such as any one of [1 "] to [7"].
[Effect of the invention]

The polishing pad of the present invention can suppress defects in the object to be polished and achieve a flat topography, and has excellent defect performance and topography performance.

(Action 1)
In the present invention, the content of the polyoxyalkylene glycol having a molecular weight of 50 to 300 with respect to the entire isocyanate-terminated urethane prepolymer is set to exceed 0% by weight and less than 5% by weight to replace the previous one. Relatively high content.

The inventors also unexpectedly discovered that by setting the content of polyoxyalkylene glycol with a molecular weight of 50 to 300 to the isocyanate-terminated urethane prepolymer as a whole to exceed 0% by weight and If it is less than 5% by weight, a polishing pad capable of suppressing defects in the object to be polished, achieving a flat topography, and having excellent defect performance and topography performance can be obtained. The specific reasons for obtaining these characteristics have not been clarified, but it is speculated as follows.

It is believed that polyoxyalkylene glycols having a molecular weight of 50 to 300, such as diethylene glycol, have high hydrophilicity because the molecular chain between the two hydroxyl groups contains oxygen atoms. Such polyoxyalkylene glycols are widely used as In the case of the raw material of the isocyanate-terminated prepolymer, the obtained isocyanate-terminated prepolymer also has high hydrophilicity. In addition, it is considered that if the isocyanate-terminated prepolymer as a component of the polishing layer has high hydrophilicity, it is easy to attract the slurry containing water to the polishing layer side during grinding, and the grinding debris existing in the slurry is also Attracted together, it is easy to produce scratches, depressions, and abrasion.
On the other hand, it is considered that in the case where only a small amount of polyoxyalkylene glycol is used as a raw material of the isocyanate-terminated prepolymer, the obtained isocyanate-terminated prepolymer is compared with the case where a large amount of polyoxyalkylene glycol is used. The hydrophobicity becomes higher (hydrophilicity becomes lower). It is also considered that if the isocyanate-terminated prepolymer, which is a component of the polishing layer, has high hydrophobicity, it is not easy to attract the grinding debris and the like existing in the slurry, so that it is not easy to generate scratches, dents, and abrasion.

(Action 2)
In the present invention, as the polyol component contained in the isocyanate-terminated urethane prepolymer, an alkylene glycol having a molecular weight of 50 to 300 is used instead of the diethylene glycol previously used.

The inventors also unexpectedly found that by using an alkylene glycol having a molecular weight of 50 to 300, it is possible to obtain defects that can suppress defects in the object to be polished and achieve a flat morphology, and the defect performance and morphology performance are excellent. Polishing pad. The specific reasons for obtaining these characteristics have not been clarified, but it is speculated as follows.

It is speculated that the diethylene glycol previously used is highly hydrophilic because the molecular chain between the two hydroxyl groups contains oxygen atoms. On the other hand, the alkylene glycol with a molecular weight of 50 to 300 is only composed of the molecular chain between the two hydroxyl groups. Carbon atoms and hydrogen atoms are formed, which results in higher hydrophobicity (lower hydrophilicity). In addition, it is considered that isocyanate-terminated prepolymers using these diols as raw materials also have the same characteristics. It is considered that if the isocyanate-terminated prepolymer as a component of the polishing layer has high hydrophilicity, it is easy to attract the slurry containing water to the polishing layer side during grinding, and the grinding debris existing in the slurry is also one. And it is attracted, so it is easy to produce scratches, depressions, and abrasion. On the other hand, if the hydrophobicity of the isocyanate-terminated prepolymer as a component of the polishing layer is high, it is not easy to attract the grinding debris and the like existing in the slurry, so that it is not easy to generate scratches, dents, and abrasion. .

Hereinafter, the polishing pad, the manufacturing method of the polishing pad, and the surface polishing method of an optical material or a semiconductor material of this invention are demonstrated.

The polishing pad of the present invention has a polishing layer containing a polyurethane resin. The polyurethane resin is a cured product of a hardening resin composition containing an isocyanate-terminated urethane prepolymer and a hardener. The isocyanate-terminated urethane The ester prepolymer is a compound (reaction product) including a polyol component having a molecular weight of 50 to 300 and a polyisocyanate component, and the content of the diol is relative to the entire isocyanate-terminated urethane prepolymer. More than 0% by weight and less than 5% by weight.

As the diol, polyoxyalkylene glycol or an alkylene glycol can be used.

The polishing pad of the present invention has a polishing layer containing a polyurethane resin. The polishing layer is disposed at a position in direct contact with the material to be polished, and other parts of the polishing pad may be composed of a material to support the polishing pad, such as a rubber-rich material. Depending on the hardness of the polishing pad, the polishing layer can be used as a polishing pad.

The polishing pad of the present invention is capable of suppressing defects in the object to be polished and achieving a flat morphology, and has excellent defect performance and morphological performance. The shape of the polishing pad is not significantly different from that of ordinary polishing pads, and can be the same as that of ordinary polishing pads. In use, for example, the polishing pad may be laminated against the material to be polished while the polishing pad is rotated, or may be polished while being pressed against the polishing layer while the material to be polished is rotated.

The polishing pad of the present invention can be produced by a manufacturing method such as die casting molding and flat plate molding which are generally known. It is manufactured by the following methods: First, a polyurethane block is formed by these manufacturing methods, the block is made into a sheet shape by slicing, etc., and a polishing layer made of a polyurethane resin is formed and attached to a support. . Alternatively, the polishing layer may be directly formed on the support.

More specifically, the polishing layer is a polishing pad according to the present invention by attaching a double-sided tape to the polishing layer on the side opposite to the polishing surface and cutting it into a predetermined shape. The double-sided tape is not particularly limited, and can be arbitrarily selected and used from the double-sided tapes known in the art. In addition, the polishing pad of the present invention may have a single-layer structure including only a polishing layer, or may include a plurality of layers formed by laminating other layers (lower layer, support layer) on the side of the polishing layer opposite to the polishing surface.

The polishing layer is formed by preparing a curable resin composition containing an isocyanate-terminated urethane prepolymer and a curing agent, and curing the curable resin composition.

The abrasive layer may include a foamed polyurethane resin, and foaming may be performed by dispersing a foaming agent containing minute hollow spheres in the polyurethane resin. In this case, a curable resin composition containing an isocyanate-terminated urethane prepolymer, a curing agent, and a foaming agent is prepared, and the curable resin composition is foamed and hardened, thereby forming it.

The curable resin composition may be, for example, a two-liquid composition prepared by mixing an A liquid containing an isocyanate-terminated urethane prepolymer and a B liquid containing a hardener component. Liquids A and B can be added to other ingredients, but in the case of a bad situation, it can be divided into multiple liquids, so that a composition composed of a mixture of three or more liquids can be used as a curable resin combination. Thing.

In the present invention, the isocyanate-terminated urethane prepolymer is preferably: a product obtained by reacting a polyol component including a diol having a molecular weight of 50 to 300 with a polyisocyanate component; A product obtained by reacting a polyol component of a polyoxyalkylene glycol having a molecular weight of 50 to 300 and a polyisocyanate component, or a polyol component including a polyalkylene glycol having a molecular weight of 50 to 300 and a polyisocyanate component. The product obtained by carrying out the reaction.

The NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is preferably less than 500, more preferably 350-495, and most preferably 400-490. By setting the NCO equivalent (g / eq) within the above numerical range, a polishing pad with appropriate polishing performance can be obtained. If the NCO equivalent (g / eq) is less than 350, the hardness of the obtained polishing pad becomes large and the defect performance is reduced. So it's not good. In addition, if the NCO equivalent (g / eq) is higher than 500, the obtained polishing pad tends to have a reduced hardness and a flattening performance, which is not preferable.

The molecular weight of the diol (preferably polyoxyalkylene glycol or alkylene glycol) contained in the isocyanate-terminated urethane prepolymer as a polyol component is 50 to 300, preferably 60 ~ 250, most preferably 70 ~ 200. The NCO equivalent (g / eq) can be adjusted by setting the molecular weight of the diol (preferably polyoxyalkylene glycol or alkylene glycol) within the above numerical range, but if the molecular weight is less than 50, then In the manufacture of prepolymers, the reactivity is high and it is not easy to control the reaction speed. If the molecular weight is greater than 300, the adjustment of the NCO equivalent (g / eq) requires a large amount of diol (preferably polyoxyalkylene glycol or elongation). Alkyl glycol), so that the hydrophilicity is high, so it is not good.

(Polyoxyalkylene glycol with a molecular weight of 50 to 300)
The content of the polyoxyalkylene glycol having a molecular weight of 50 to 300 relative to the entire isocyanate-terminated urethane prepolymer exceeds 0% by weight and less than 5% by weight, preferably 0.5 to 4% by weight, and most preferably It is 1 to 3% by weight. By making the content of the polyoxyalkylene glycol within the above-mentioned numerical range, defects in the object to be polished can be suppressed and a flat morphology can be realized.

As the polyoxyalkylene glycol having a molecular weight of 50 to 300, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, etc. can be used, and the NCO equivalent (g / From the viewpoint of adjustment of eq), diethylene glycol having a relatively low molecular weight is preferably used.

In the case where the isocyanate-terminated urethane prepolymer contains a polyoxyalkylene glycol having a molecular weight of 50 to 300, the isocyanate-terminated urethane prepolymer contains a molecular weight other than 50 to 300. Examples of the polyol component other than polyoxyalkylene glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, and 1 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1 Low molecular weight (molecular weight 50-300, such as 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol) Of) polyalkylene glycols; polyoxytetramethylene glycol (PTMG), polyethylene glycol, polypropylene glycol and other polyether polyols; reactants of ethylene glycol and adipic acid or butanediol and Polyester polyols such as adipic acid reactants; polycarbonate polyols; polycaprolactone polyols.
Among these, polyoxytetramethylene glycol is preferably used from the viewpoints of the rationality of the prepolymer or the mechanical strength of the obtained polishing pad. The number average molecular weight of the polyoxytetramethylene glycol is preferably 500 to 2000, more preferably 600 to 1,000, and most preferably 650 to 850.

In the case where the isocyanate-terminated urethane prepolymer includes a polyoxyalkylene glycol having a molecular weight of 50 to 300, the isocyanate-terminated urethane prepolymer may include the above-mentioned lows listed as a polyol component The molecular weight (50 to 300 molecular weight) of alkylene glycol may or may not be included. As the low molecular weight (50 to 300 molecular weight) alkylene glycol, the above-mentioned ones listed as the polyol component can be used.
When the isocyanate-terminated urethane prepolymer contains a polyoxyalkylene glycol having a molecular weight of 50 to 300 and further contains an alkylene glycol having a molecular weight of 50 to 300, an alkylene having a molecular weight of 50 to 300 The content of the diol with respect to the entire isocyanate-terminated urethane prepolymer is preferably 0 to 5% by weight, more preferably 0.5 to 4% by weight, and most preferably 1 to 3% by weight. Here, the term "excluding low-molecular-weight (50-300 molecular weight) alkylene glycol" means that it is not contained as an intentional additive, and even when contained as an impurity, the isocyanate-blocked urethane The entire prepolymer is also preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and most preferably 0.01% by mass or less. By setting the content of the low molecular weight (50 to 300 molecular weight) alkylene glycol within the above-mentioned numerical range, defects in the object to be polished can be suppressed and a flat morphology can be achieved.

(Dialkylene glycol with a molecular weight of 50 to 300)
The content of the alkylene glycol with a molecular weight of 50 to 300 relative to the entire isocyanate-terminated urethane prepolymer exceeds 0% by weight and less than 5% by weight, preferably 0.5 to 4% by weight, and most preferably 1 ~ 3% by weight. By setting the content of the alkylene glycol within the above numerical range, defects in the object to be polished can be suppressed and a flat morphology can be realized.

The alkylene glycol having a molecular weight of 50 to 300 is not particularly limited, and a linear or branched one may be used, and a molecular end having a hydroxyl group may be used. As the alkylene glycol having a molecular weight of 50 to 300, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, 4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc., in terms of NCO equivalent (g / eq From the standpoint of adjustment, 1,4-butanediol is preferably used because its molecular weight is similar to that of diethylene glycol previously used.

In the present invention, an alkylene glycol having a molecular weight of 50 to 300 can be used to replace all or part of the diethylene glycol previously used to produce an isocyanate-terminated urethane prepolymer.

In the case where the isocyanate-terminated urethane prepolymer contains an alkylene glycol having a molecular weight of 50 to 300, the isocyanate-terminated urethane prepolymer contains an alkylene glycol having a molecular weight other than 50 to 300. Examples of polyhydric alcohol components other than glycols include low molecular weight (50 to 300 molecular weight) polyoxyethylene such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol. Alkyl glycols; polyetherpolyols such as polyoxytetramethylene glycol (PTMG), polyethylene glycol, and polypropylene glycol; reactants of ethylene glycol and adipic acid or butanediol and adipic acid Reactants such as polyester polyols; polycarbonate polyols; polycaprolactone polyols.
Among these, polyoxytetramethylene glycol is preferably used from the viewpoints of the rationality of the prepolymer or the mechanical strength of the obtained polishing pad. The number average molecular weight of the polyoxytetramethylene glycol is preferably 500 to 2000, more preferably 600 to 1,000, and most preferably 650 to 850.

When the isocyanate-terminated urethane prepolymer contains an alkylene glycol having a molecular weight of 50 to 300, the isocyanate-terminated urethane prepolymer may include the above-mentioned low molecular weight ( Polyoxyalkylene glycols (with a molecular weight of 50 to 300) may not be included. As the low molecular weight (50 to 300 molecular weight) polyoxyalkylene glycol, the above-mentioned ones listed as the polyol component can be used.
When the isocyanate-terminated urethane prepolymer contains an alkylene glycol having a molecular weight of 50 to 300 and further contains a polyoxyalkylene glycol having a molecular weight of 50 to 300, a polyoxyethylene having a molecular weight of 50 to 300 The content of the alkyl diol with respect to the entire isocyanate-terminated urethane prepolymer is preferably more than 0% by weight and less than 3% by weight, more preferably 0.1 to 2.8% by weight, and most preferably 0.2 to 2.5% by weight. %. Here, "low molecular weight (50 to 300) polyoxyalkylene glycol is not included" means that it is not contained as an intentional additive, and even when contained as an impurity, it is blocked with isocyanate-terminated aminomethyl The entire acid ester prepolymer is also preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and most preferably 0.01% by mass or less. By setting the content of the low molecular weight (50 to 300) polyoxyalkylene glycol within the above numerical range, defects in the object to be polished can be suppressed and a flat morphology can be achieved.

Examples of the polyisocyanate component included in the isocyanate-terminated urethane prepolymer include, for example, m-phenylene diisocyanate, terephthalic acid diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), and 2, 4-toluene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis (cyclic Hexyl isocyanate) (hydrogenated MDI), 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, benzene Dimethyl-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene -1,2-diisocyanate, cyclohexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, p-phenylenediisothiocyanate, xylylene-1,4-diiso Thiocyanate, ethylidene diisothiocyanate, etc.
Among these, 2,6-toluene diisocyanate (2,6-TDI), 2,4-toluene diisocyanate (2,4) are preferably used from the viewpoint of the polishing characteristics or mechanical strength of the obtained polishing pad. -TDI) and other toluene diisocyanates.

As a hardening | curing agent contained in a curable resin composition, the amine hardening | curing agent demonstrated below is mentioned, for example.
Examples of the polyamine constituting the amine-based hardener include diamines. Among the diamines, alkylene diamines such as ethylene diamine, propylene diamine, and hexamethylene diamine; Isophorone diamine, dicyclohexylmethane-4,4'-diamine and other diamines with aliphatic rings; 3,3'-dichloro-4,4'-diaminodiphenylmethane (alias: Methylene bis-o-chloroaniline) (hereinafter referred to as MOCA) diamines with aromatic rings; 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl ethylenediamine, di-2-hydroxyethyl Diamines with hydroxyl groups, such as diethylene glycol diamine, di-2-hydroxyethyl ethylene diamine, 2-hydroxypropyl ethylene diamine, di-2-hydroxypropyl ethylene diamine, especially hydroxyalkane Alkylene diamine; etc. Moreover, a trifunctional triamine compound and a tetrafunctional or more polyamine compound can also be used.

A particularly preferred hardener is the aforementioned MOCA, and the chemical structure of the MOCA is as follows.

[Chemical 1]

The amount of the entire hardener is the ratio of the mole number of NH ₂ of the hardener to the mole number of NCO of the isocyanate-terminated urethane prepolymer (mole number of NH ₂ / The molar number of NCO) is preferably 0.7 to 1.1, more preferably 0.75 to 1.0, and most preferably 0.8 to 0.95.

In the present invention, the curable resin composition may further include fine hollow spheres.
Foams can be formed by mixing tiny hollow spheres with a polyurethane resin. The term "small hollow sphere" refers to a product obtained by thermally expanding an outer shell (polymer shell) made of a thermoplastic resin and an unfoamed, thermally expandable microsphere containing a low boiling point hydrocarbon contained in the outer shell. Examples of the polymer shell include thermoplastic resins such as acrylonitrile-vinylidene chloride copolymer, acrylonitrile-methyl methacrylate copolymer, and vinyl chloride-ethylene copolymer. Similarly, as the low-boiling hydrocarbon contained in the polymer shell, for example, isobutane, pentane, isopentane, and petroleum ether can be used.

In addition, a catalyst or the like commonly used in the art may be added to the curable resin composition.
In addition, the above-mentioned polyisocyanate component may be added to the curable resin composition, and the ratio of the weight of the additional polyisocyanate component to the total weight of the isocyanate-terminated urethane prepolymer and the additional polyisocyanate component may be added. It is preferably 0.1 to 10% by weight, more preferably 0.5 to 8% by weight, and even more preferably 1 to 5% by weight.
The polyisocyanate component added to the polyurethane resin curable composition is not particularly limited, and the polyisocyanate component described above can be used, but 4,4'-methylene-bis (cyclohexyl isocyanate) (hydrogenated MDI) is preferred. ).

The contact angle of the polishing layer in the polishing pad of the present invention with respect to water is preferably greater than 70 °, more preferably 75 ° or more, and most preferably 80 ° or more. If the contact angle is 70 ° or less, the hydrophilicity becomes high, and the time for holding the slurry containing the grinding debris becomes longer, so that the defect tends to become larger. In the present invention, the contact angle of water is measured by a droplet method using an automatic contact angle meter (DropMaster 500 manufactured by Kyowa Interface Science Co., Ltd.) as described below.
[Example]

The present invention is experimentally described by the following examples, but the following description is not intended to limit the scope of the present invention to the following examples.

(material)
List the materials used in the following examples.

・ Isocyanate-terminated urethane prepolymer:
Prepolymer (1) ... Prepolymerization of urethane prepolymers containing toluene diisocyanate as a polyisocyanate component and polytetramethylene ether glycol having a number average molecular weight of 650 as an NCO equivalent of 513 as a polyol component (2) ..... Contains toluene diisocyanate as a polyisocyanate component, and polytetramethylene glycol and diethylene glycol with a number average molecular weight of 650 (1% by weight based on the entire prepolymer) as polyol components. NCO equivalent 486 urethane prepolymer prepolymer (3) .... Contains toluene diisocyanate as a polyisocyanate component, and polytetramethylene ether glycol and diethylene glycol (relative to the number average molecular weight 650 (relatively 2% by weight of the entire prepolymer) NCO equivalent of 463 as a polyol component, a urethane prepolymer prepolymer (4) ... containing toluene diisocyanate as a polyisocyanate component, and a number average molecular weight of 650 Polytetramethylene ether glycol and diethylene glycol (3% by weight based on the entire prepolymer) as urethane prepolymer prepolymers with an NCO equivalent of 450 as the polyol component (5) ... Toluene diisocyanate as a polyisocyanate NCO with polytetramethylene ether glycol having a number average molecular weight of 650, polytetramethylene ether glycol with a number average molecular weight of 1,000, and diethylene glycol (5% by weight relative to the entire prepolymer) as the polyol NCO Equivalent 437 urethane prepolymer prepolymer (1 ') ... contains toluene diisocyanate as a polyisocyanate component, and polytetramethylene ether glycol with a number average molecular weight of 650 and 1,4-butane Alcohol (1% by weight based on the entire prepolymer) NCO equivalent of 484 as a polyol component Urethane prepolymer prepolymer (2 ') ... includes toluene diisocyanate as a polyisocyanate component and quantity Polytetramethylene ether glycol having an average molecular weight of 650 and 1,4-butanediol (2% by weight based on the entire prepolymer) as urethane prepolymer prepolymers having an NCO equivalent of 459 as a polyol component (3 ') ... Polyurethane diisocyanate is included as a polyisocyanate component, and polytetramethylene glycol and 1,4-butanediol (3% by weight based on the entire prepolymer) are included as a multicomponent Urethane prepolymer prepolymer (4 ') with NCO equivalent of 439 of alcohol component Isocyanate as a polyisocyanate component, and polytetramethylene ether glycol with a number average molecular weight of 650, 1,4-butanediol (1% by weight based on the entire prepolymer), and diethylene glycol (with respect to the prepolymer) 1% by weight) Urethane prepolymer of NCO equivalent 441 as a polyol component

·hardener:
MOCA ... 3,3'-dichloro-4,4'-diaminodiphenylmethane (alias: methylenebis-o-chloroaniline) (NH ₂ equivalent = 133.5)
・ Product name of tiny hollow sphere:
EXPLCEL 551DE40d42 made by Japan Fillite

<Examples 1 to 3 and Comparative Example 1>
(Example 1)
100 g of the prepolymer (2) was prepared as the A component, 24 g of MOCA as the hardener was used as the B component, and 4.5 g of fine hollow spheres (EXPANCEL 551DE40d42) were used as the C component. In addition, the ratio of the mole number of NH ₂ of the amine hardener of the B component to the mole number of the NCO of the prepolymer of the A component (mole number of NH ₂ / mole number of NCO) was 0.87. In addition, the ratio is described in g, and the required weight (parts) is prepared according to the size of the block. Hereinafter, it will be described in the same g (parts) notation.
The A component and the C component are mixed, the mixture of the A component and the C component is decompressed under reduced pressure, and thereafter, the mixture of the A component and the C component and the B component are supplied to the mixer.
The obtained mixed solution was cast into a mold frame heated to 80 ° C., and the formed resin foam was extracted from the mold frame after being heated for 1 hour to harden, and then cured at 120 ° C. for 5 hours. This foam was sliced to a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

(Example 2)
100 g of the prepolymer (3) was prepared instead of 100 g of the prepolymer (2) of the component A of Example 1.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.

(Example 3)
100 g of the prepolymer (4) was prepared in place of 100 g of the prepolymer (2) of the component A of Example 1.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.

(Comparative example 1)
100 g of the prepolymer (5) was prepared in place of 100 g of the prepolymer (2) of the component A of Example 1.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 1 to obtain a polishing pad.
(Comparative example 2)
100 g of the prepolymer (1) was prepared in place of 100 g of the prepolymer (2) of the component A of Example 1. Hereinafter, an attempt was made to form a urethane sheet in the same manner as in Example 1. However, since the curable resin composition containing the A component, the B component, and the C component took a long time to cure, the curing was not sufficiently performed. It is not easy to slice the obtained foam, and it is impossible to obtain a polishing pad.

(experiment method)
Each of the urethane sheets (polishing pads) of Examples 1 to 3 and Comparative Example 1 was subjected to the following density, A hardness, and D hardness measurements.
(density)
The density (g / cm ³ ) is measured in accordance with Japanese Industrial Standards (JIS K 6505).
(A hardness)
The A hardness of the polishing pad was measured using a Shore A hardness tester in accordance with Japanese Industrial Standards (JIS-K-7311). Here, the sample is obtained by overlapping a plurality of urethane sheets as necessary so that the total thickness is at least 4.5 mm or more.
(D hardness)
The D hardness of the polishing pad is measured using a D-type hardness tester in accordance with Japanese Industrial Standards (JIS-K-6253). Here, the sample is obtained by overlapping a plurality of urethane sheets as necessary so that the total thickness is at least 4.5 mm or more.

Table 1 shows the basic physical properties of the polishing pads obtained in Examples 1 to 3 and Comparative Example 1.

[Table 1]
Table 1

(Grinding rate)
The polishing rate (Å) of each of the polishing pads of Examples 1 to 3 and Comparative Example 1 was measured. The conditions of the polishing test are as follows.

(Conditions of grinding test)
・ Using grinder: F-REX300 manufactured by Ebara Manufacturing Co., Ltd.
・ Disk: 3MA188 (# 100)
・ Rotating speed: (platen) 70 rpm, (top ring) 71 rpm
・ Grinding pressure: 3.5 psi, 2.9 psi, or 1.5 psi. ・ Abrasive: made by Cabot, product number: SS25 (using SS25 stock solution: pure water = 1: 1 mixed solution)
・ Abrasive temperature: 20 ℃
・ Abrasive discharge: 200 ml / min
・ Workpiece (object to be polished): A substrate formed on a 12-inch silicon wafer to make tetraethoxysilane (TEOS) an insulating film with a thickness of 1 μm by PE-CVD. The initial temperature of the polishing is 20 ° C, and the surface temperature of the pad rises to 40-50 ° C during the polishing.
・ The polishing rate is after grinding for 10 minutes to polish the first to 51 wafers at 3.5 psi, to polish the 52nd wafer at 2.9 psi, and to polish at 1.5 psi The 53rd wafer was polished and the values measured for the 1st, 5th, 10th, 15th, 20th, 25th, 50th, 52th, and 53th wafers.

The evaluation results of the polishing rate (Å) are shown in Table 2 and FIG. 1. Figure 1 shows the polishing rate (Å) in 3.5 psi (50th wafer), 2.9 psi (52th wafer), and 1.5 psi (53rd wafer).

[Table 2]
Table 2

(defect)
Defects such as scratches on the polishing pads of Examples 1 to 3 and Comparative Example 1 were evaluated as described below.
The evaluation of defects such as scratches is based on the above (polishing rate) (conditions of the polishing test) of 51 substrates, and the wafer surface inspection apparatus (manufactured by KLA-Tencor, Surfscan SP2xpDLS) is used for high-sensitivity measurement mode. The 11th, 26th, and 51th substrates were measured after grinding, and the number of defects in the surface of the substrate (fine dent-like scratches of 0.2 μm to 10 μm) was measured. to evaluate.

The evaluation results of the defects are shown in Table 3 and FIG. 2.

[table 3]
table 3

As can be seen from the results in Table 2 and FIG. 1, the polishing pads of Examples 1 to 3 and Comparative Example 1 exhibited sufficient polishing rate (Å) as a polishing pad, and had excellent polishing properties. In addition, it can be seen that the polishing pads of Examples 1 to 3 and Comparative Example 1 showed the same degree of polishing rate (Å) under the polishing pressures of any of 3.5 psi, 2.9 psi, and 1.5 psi, and no larger polishing rate was observed. difference.

As can be seen from the results in Table 3 and FIG. 2, the content of diethylene glycol relative to the entire isocyanate-terminated urethane prepolymer was 1% by weight, 2% by weight, or 3% by weight of Examples 1 to 3. Abrasive pads have fewer defects and are considered good results.
On the other hand, it can be seen that the polishing pad of Comparative Example 1 in which the content of diethylene glycol relative to the entire isocyanate-terminated urethane prepolymer was 5 wt% had many defects.
From the results of Examples 1 to 3 and Comparative Example 1, it can be seen that as the content of diethylene glycol relative to the entire isocyanate-terminated urethane prepolymer decreases, defects such as scratches decrease, which is considered to be a good result.
In addition, as shown in Comparative Example 2, if the content of diethylene glycol is set to 0% by weight, there is a problem that the reaction time becomes long and it takes a long time until it is hardened. Therefore, the productivity is poor and the hardening is further accelerated. Slicing cannot be performed smoothly in the subsequent slicing step.

As described above, the polishing pads of Examples 1 to 3 have a high polishing rate (Å), excellent polishing properties, and can suppress defects in the object to be polished. On the other hand, although the polishing pad of Comparative Example 1 had a high polishing rate (Å) and excellent polishing properties, there were many defects in the object to be polished.

Based on the above results, it was confirmed that the polishing pad whose content of diethylene glycol relative to the entire isocyanate-terminated urethane prepolymer exceeds 0% by weight and less than 5% by weight can suppress defects in the object to be polished and achieve flatness. Morphology, and excellent defect performance and morphology performance.

<Examples 4 to 7, Comparative Example 3>
(Example 4)
100 g of the prepolymer (1 ′) was used as the A component, 24 g of MOCA as the hardener was used as the B component, and 4.5 g of micro hollow spheres (EXPANCEL 551DE40d42) were used as the C component. In addition, the ratio of the mole number of NH ₂ of the amine hardener of the B component to the mole number of the NCO of the prepolymer of the A component (mole number of NH ₂ / mole number of NCO) was 0.87. In addition, the ratio is described in g, and the required weight (parts) is prepared according to the size of the block. Hereinafter, it will be described in the same g (parts) notation.
The A component and the C component are mixed, the mixture of the A component and the C component is decompressed under reduced pressure, and thereafter, the mixture of the A component and the C component and the B component are supplied to the mixer.
The obtained mixed solution was cast into a mold frame heated to 80 ° C., and the formed resin foam was extracted from the mold frame after being heated for 1 hour to harden, and then cured at 120 ° C. for 5 hours. This foam was sliced to a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

(Example 5)
100 g of the prepolymer (2 ') was prepared in place of 100 g of the prepolymer (1') of the component A of Example 4.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 4 to obtain a polishing pad.

(Example 6)
100 g of the prepolymer (3 ') was prepared in place of 100 g of the prepolymer (1') of the component A of Example 4.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 4 to obtain a polishing pad.

(Example 7)
100 g of the prepolymer (4 ') was prepared in place of 100 g of the prepolymer (1') of the component A of Example 4.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 4 to obtain a polishing pad.

(Comparative example 3)
100 g of the prepolymer (5) was prepared in place of 100 g of the prepolymer (1 ′) of the component A of Example 4.
Hereinafter, a urethane sheet was prepared in the same manner as in Example 4 to obtain a polishing pad.

(experiment method)
Regarding each of the polishing pads of Examples 4 to 7 and Comparative Example 3, the following contact angles were measured and defects were evaluated.

(Contact angle)
Regarding the surfaces of the urethane sheets of Examples 4 to 7 and Comparative Example 3, the contact angle of water was measured. The contact angle of water was measured by a droplet method using an automatic contact angle meter (DropMaster 500, manufactured by Kyowa Interface Science Co., Ltd.). That is, add distilled water to the syringe of the automatic contact angle meter, and drop 1 drop (1 μL) of water droplets from the injection needle on the surface of the abrasive sheet at a temperature of 20 ° C and a humidity of 50%, and read 300 seconds after the drop. Contact angle.

(defect)
The evaluation of the defects is based on the polishing of 25 substrates based on the following grinding test conditions. The 5th of the 21st to 25th wafers after polishing are processed in the high-sensitivity measurement mode of a wafer surface inspection device (manufactured by KLA-Tencor, SurfscanSP2xpDLS) The substrate was measured, and the number of scratches caused by grinding debris was evaluated. In the evaluation of defects, a defect of 0.16 μm or more on a 12-inch (300 mm <b) wafer is regarded as ○ when it is less than 200, and it is regarded as × when it is more than 200.

(Conditions of grinding test)
・ Grinding machine used: F-REX300, manufactured by Ebara Manufacturing Co., Ltd.
・ Disk: 3MA188 (# 100)
・ Rotating speed: (platen) 70 rpm, (top ring) 71 rpm
・ Grinding pressure: 3.5 psi
・ Abrasive: made by Cabot, product number: SS25 (using SS25 stock solution: pure = mixed solution with a weight ratio of 1: 1)
・ Abrasive temperature: 20 ℃
・ Abrasive discharge: 200 ml / min
・ Workpiece (object to be polished): A substrate formed on a 12-inch silicon wafer by using PE-CVD to make tetraethoxysilane into an insulating film with a thickness of 1 μm. The initial temperature of self-polishing is 20 ° C. During this period, the surface temperature of the pad rose to 40-50 ° C.

The above results are shown in Table 4.

[Table 4]
Table 4
* 1,4-BD: 1,4-butanediol, DEG: diethylene glycol *-: It is not added as a component.

As shown in Table 4, the polishing pads of Examples 4 to 7 had a contact angle of 75 ° or more, which was more hydrophobic than the polishing pad of Comparative Example 3, and could suppress the generation of scratches. In addition, from the results of Examples 4 to 7 and Comparative Example 3, it can be seen that if the amount of 1,4-butanediol, which is an alkylene glycol, which is relatively high in hydrophobicity, is increased, or the polyoxygen, which is relatively hydrophilic, is decreased. The amount of diethylene glycol added to the alkylene glycol tends to increase the contact angle of the polishing pad.

Based on the above results, it was confirmed that the polishing pad whose content of 1,4-butanediol relative to the entire isocyanate-terminated urethane prepolymer exceeds 0% by weight and less than 5% by weight can suppress defects in the object to be polished. And achieve a flat topography, and excellent defect performance and topography performance.

FIG. 1 is a graph showing evaluation results of polishing rates (Å) in Examples 1 to 3 and Comparative Example 1. FIG.

FIG. 2 is a graph showing evaluation results of defects in Examples 1 to 3 and Comparative Example 1. FIG.

Claims (13)

A polishing pad having a polishing layer containing a polyurethane resin, and The polyurethane resin is a cured product of a curable resin composition containing an isocyanate-terminated urethane prepolymer and a hardener. The isocyanate-terminated urethane prepolymer includes a diol having a molecular weight of 50 to 300. The reaction product of the polyol component and the polyisocyanate component, and the content of the diol is more than 0% by weight and less than 5% by weight relative to the entire isocyanate-terminated urethane prepolymer. The polishing pad according to claim 1, wherein the diol is polyoxyalkylene glycol. The polishing pad according to claim 2, wherein the polyoxyalkylene glycol is diethylene glycol. The polishing pad according to claim 1, wherein the diol is an alkylene glycol. The polishing pad according to claim 4, wherein the alkylene glycol-based linear compound has a hydroxyl group at a molecular terminal. The polishing pad according to claim 5, wherein the alkylene glycol is 1,4-butanediol. The polishing pad according to any one of claims 1 to 6, wherein the NCO equivalent (g / eq) of the isocyanate-terminated urethane prepolymer is less than 500. The polishing pad according to any one of claims 1 to 7, wherein the polyisocyanate component includes toluene diisocyanate. The polishing pad according to any one of claims 1 to 8, wherein the polyol component further comprises polyoxytetramethylene glycol. The polishing pad according to any one of claims 1 to 9, wherein the hardener comprises 3,3'-dichloro-4,4'-diaminodiphenylmethane. The polishing pad according to any one of claims 1 to 10, wherein the curable resin composition further contains fine hollow spheres. A method for manufacturing a polishing pad according to any one of claims 1 to 11, and The method includes the step of forming the polishing layer. A method which is a surface polishing method of an optical material or a semiconductor material, and the above method uses a polishing pad according to any one of claims 1 to 11.