TW201636406A - Polishing pad - Google Patents

Abstract

The present invention provides a polishing pad with which the surface of a polishing layer is softened during a polishing process. The polishing pad comprises a polishing layer having polyurethane resin, wherein the polishing layer is formed by curing the polyurethane resin comprising a polyisocyanate compound, a polyol compound, a curing agent, and micro hollow spheres .

Description

Abrasive pad

The present invention relates to an abrasive sheet or a polishing pad for polishing a material requiring a high degree of surface flatness such as an optical material, a substrate for a semiconductor, a semiconductor wafer, a hard disk substrate, a glass substrate for liquid crystal, or a semiconductor device.

Extremely precise flatness is required for optical materials, semiconductor substrates, semiconductor wafers, hard disk substrates, liquid crystal glass substrates, and semiconductor devices. Further, various materials having different hardnesses such as metal, organic and inorganic insulating materials are exposed on the surface of the semiconductor material. In order to grind the surface of such a material to a flat surface, the surface of the polishing pad must also maintain flatness at all times. When the rigidity of the surface of the polishing pad changes during the polishing operation, the desired flatness cannot be achieved. For example, it is impossible to achieve precise flatness due to the surface of the polishing pad which is locally lowered in rigidity, and a phenomenon in which only the metal portion is preferentially polished (depression) or the like occurs.

On the other hand, a considerable amount of grinding debris is generated from the beginning of the first grinding operation to the replacement of the polishing pad and the polishing liquid. The clogging of the opening occurs due to the accumulation of the grinding debris, and the retention of the slurry is deteriorated, resulting in frictional heat. Therefore, during the first polishing operation, the temperature of the surface of the material to be polished rises from the initial stage to the final stage, and includes 30 ° C. It varies over a wide temperature range of 90 °C. Therefore, it is possible to locally change the rigidity of the surface of the polishing pad in accordance with the temperature change. Further, since the polishing liquid used for chemical mechanical polishing increases in temperature, the chemical action (corrosion of the surface of the non-abrasive material) becomes strong, so that it tends to cause a larger scratch.

Paragraph 0072 of Patent Document 1 (Japanese Patent Laid-Open Publication No. 2008-207324) There are: D hardness [D (23 ° C, wet)] of the polishing pad at 23 ° C when saturated swelling with 50 ° C of warm water and D hardness of the polishing pad at 23 ° C [D (23 ° C, dry)] The ratio [D (23 ° C, wet)] / [D (23 ° C, dry)] is about 0.9 to 1.1; the polishing pad having a ratio of 0.9 or more can be obtained by [E' (50 ° C, dry)] / [E '(50 ° C, wet)) is obtained by a polishing pad of about 2.5 or less.

On the other hand, in paragraph 0068 of Patent Document 1, it is described that the temperature dependence of the storage elastic modulus of the polyurethane elastomer is large, and the temperature dependency thereof changes due to water absorption, but in general, [E' (23 ° C, wet) / E' (50 ° C, wet)] of the polyurethane elastomer is large (for example, about 2.5 to 20); and in the polishing pad of Patent Document 1, for example, It is possible to reduce the [E' (23 ° C, wet) / E' (50 ° C, wet) of the polishing pad by filling a large amount of extremely fine single fibers including a thermoplastic resin having a glass transition temperature of 50 ° C or higher and a water absorption ratio of 4% by mass or less. )].

Although Patent Document 1 proposes to further reduce the difference in hardness between drying and wetting, it is revealed that it is difficult to achieve only a polyurethane elastomer.

In the patent document 2 (JP-A-2006-144156), it is disclosed that the difference between the Shore A hardness at room temperature and 60 ° C can be suppressed to 14 or less, and a high level can be stably provided. Flatness of the polishing pad. However, Patent Document 2 does not describe the difference in hardness between the surface of the polishing layer and the inside.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-207324

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-144156

The present invention provides a polishing pad in which the surface of the polishing layer is softened during polishing.

That is, the present invention provides the following.

[1] A polishing pad characterized by comprising a polishing layer comprising a polyurethane resin, wherein the polishing layer comprises a polyisocyanate compound, a polyol compound, a hardener, and a micro hollow sphere. The urethane resin curable composition is formed by hardening, and the following formula: {(D hardness of the polishing pad in a dry state) - (D hardness of the polishing pad which is swelled by warm water at 40 ° C)} / ( The D hardness of the polishing pad in the dry state is 0.1 to 0.3, and the following formula: {(the storage elastic modulus of the polishing pad in a dry state) - (the storage elastic modulus of the polishing pad which is swollen by warm water at 40 ° C) The value of the number /) (the storage elastic modulus of the polishing pad in the dry state) is 0.4 to 0.7.

[2] A polishing pad characterized by comprising a polishing layer comprising a polyurethane resin, wherein the polishing layer comprises a polyisocyanate compound, a polyol compound, and a 3,3'-dichloro group. The hardening agent of 4,4'-diaminodiphenylmethane and the hardening composition of the micro hollow sphere urethane resin are hardened, and the hardener is 100% by weight based on the total amount of the hardener. It comprises 3 to 10% by weight of a tetramer.

Here, the above tetramer is, for example, represented by the following formula: [Chemical Formula 1] Said.

[3] A polishing pad characterized by comprising a polishing layer comprising a polyurethane resin, wherein the polishing layer comprises a polyisocyanate compound, a polyol compound, a hardener, and a micro hollow sphere. The urethane resin curable composition is formed by curing, and at least has a surface layer portion which softens during wet grinding.

[4] The polishing pad according to [3], wherein the thickness of the surface layer portion is 50 μm or less.

[5] The polishing pad according to [3], wherein the thickness of the surface portion is smaller than the diameter of the minute hollow sphere.

[6] The polishing pad according to [3], wherein in the needle insertion test by thermomechanical analysis (TMA), the needle insertion temperature of the first stage is 50 to 100 ° C, and the needle insertion temperature of the second stage It is above 150 °C.

[7] The polishing pad according to any one of [1] to [6] wherein the polyisocyanate compound and the polyol compound comprise a prepolymer prepared by reacting a polyisocyanate compound with a polyol compound.

[8] A grinding method characterized in that it is an abrasive optical material or a semiconductor material A method of using a polishing pad as described in any one of [1] to [6].

[9] A method of reducing scratches when polishing an optical material or a surface of a semiconductor material, which uses the polishing pad according to any one of [1] to [6] to reduce the surface of the abrasive optical material or semiconductor material Scratch at the time.

According to the invention, the surface of the polishing layer is softened by polishing (about 40 ° C), and defects such as scratches of the object to be polished can be suppressed. Further, by having an appropriate hardness inside the polishing layer, a high polishing rate can be maintained.

Fig. 1 is a schematic view showing a needle insertion test by thermomechanical analysis (TMA).

Fig. 2 is a view showing the results of a needle insertion test of the polishing pad of Example 1.

Fig. 3 is a view showing the results of a needle insertion test of the polishing pad of Example 2.

Fig. 4 is a view showing the results of a needle insertion test of the polishing pad of Comparative Example 1.

(polishing pad)

The polishing pad of the present invention has an abrasive layer comprising a foamed polyurethane resin. The polishing layer is disposed in direct contact with the material to be polished, and other portions of the polishing pad may also include materials for supporting the polishing pad, such as elastic materials such as rubber. Depending on the rigidity of the polishing pad, the polishing pad can be integrally formed as one polishing layer.

The polishing pad of the present invention can be used in the same manner as a general polishing pad, and can be used in the same manner as a general polishing pad, in addition to the fact that the polishing pad is not easily scratched by the polishing material, and the like, and can be used in the same manner as a general polishing pad. The polishing pad is polished and laminated against the material to be polished, and the material to be polished can be pressed against the polishing layer while being rotated.

One aspect of the polishing pad of the present invention is characterized in that the polishing layer is made to contain polyisocyanide The ester compound, the polyol compound, the curing agent, and the urethane composition of the micro hollow sphere are cured, and the following formula (I): {(D hardness of the polishing pad in a dry state) - (D hardness of the polishing pad saturated with warm water at 40 ° C)} / (D hardness of the polishing pad in a dry state) is 0.1 to 0.3, more preferably 0.15 to 0.25, and the following formula (II): (The storage elastic modulus of the polishing pad in a dry state) - (the storage elastic modulus of the polishing pad saturated with warm water at 40 ° C)} / (the storage elastic modulus of the polishing pad in a dry state) is 0.4~ 0.9, more preferably 0.6~0.85.

The inventors of the present invention have found that the polishing properties of the polishing pad can be improved by limiting the values of the above formulas (I) and (II) to a specific range. The numerical range of the above formula (I) means that the D hardness of the polishing pad when wet is reduced by 10 to 30% when dry, and the numerical range of the above formula (II) means that the storage elastic modulus of the polishing pad when wet is relatively dry. Reduce 40~90%. In other words, when the polishing temperature of the polishing pad of the present invention reaches 40° C., the hardness and the modulus of elasticity of the surface are lowered, and the film is deformed so as not to cause scratches or the like. However, since the deformation is limited to the surface of the polishing pad, the polishing pad is limited to the surface of the polishing pad. The hardness and modulus of elasticity of the polishing pad as a whole are not excessively lowered to obtain the desired flatness or polishing rate.

Further, since the bubbles of the polishing layer of the present invention are independent bubbles and the bubbles are not in communication with each other, even if the surface of the polishing layer is exposed to water, water does not permeate into the inside of the polishing layer through the bubbles, and the internal dry state can be maintained.

Another aspect of the polishing pad of the present invention is characterized in that the polishing layer comprises a polyisocyanate compound, a polyol compound, and 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter The hardening agent called "MOCA" and the polyurethane resin curable composition of the micro hollow spheres are formed by curing, and the total amount of the curing agent is 100% by weight, and the fourth formula is included. The polymer is 3 to 10% by weight, preferably 4 to 8% by weight, more preferably 5 to 7% by weight. The chemical structure of MOCA is The chemical structure of the tetramer is

A tetramer is a compound having a reactive group of four amine groups in one molecule, and the reactivity of the four amine groups is sequentially lowered, the first > the second > the third > the fourth. Therefore, the reactivity of the tetramer is milder than that of MOCA (3,3'-dichloro-4,4'-diaminodiphenylmethane) having two amine groups in one molecule. When a hardener containing a large amount of tetramer is used, the reactivity of the fourth amine group may not be reacted due to a decrease in reactivity or steric hindrance, and it is considered that the heat resistance of the obtained hardened body is lowered (it becomes a resin easy) The tendency to soften).

A further aspect of the polishing pad of the present invention is characterized in that the polishing layer is a polyamine comprising a polyisocyanate compound, a polyol compound, a hardener, and a micro hollow sphere. The urethane resin curable composition is formed by curing, and at least has a surface layer portion which softens during wet polishing.

In the surface layer portion of the characteristic, it is preferable that the thickness of the surface layer portion is 50 μm or less, and it is particularly preferable that the thickness of the surface layer portion is smaller than the diameter of the minute hollow sphere.

Please refer to the accompanying drawings and the embodiments described below. In the needle insertion test by the thermomechanical analysis method (TMA), in the examples of the present invention, it can be confirmed that the needle insertion temperature of the first stage is 50 to 100 ° C, and the needle insertion temperature of the second stage is 150 ° C or more. The 2 stages are inserted. In the first stage, the penetration depth is 50 μm or less, but the diameter of the micro hollow sphere used in the embodiment is about 55 μm, so that it can be understood that the penetration depth of the first stage is not affected by the needle. The effect of movement or deformation of the hollow sphere. On the other hand, the polishing pad of the comparative example did not show the two-stage needle-in temperature and only showed the one-stage needle-in temperature exceeding 150 °C.

That is, when the polishing temperature of the polishing pad of the present invention reaches 40 ° C, the surface starts to soften, but the entire polishing pad is not softened to maintain flatness. Therefore, the surface is softened so as not to cause scratches or the like during polishing. However, since the softening is limited to the surface of the polishing pad, the entire polishing pad is not excessively softened so that the desired flatness or polishing cannot be obtained. rate.

(Method of manufacturing polishing pad)

The polishing pad of the present invention can be produced by a conventionally known production method such as die casting or slab forming. First, a polyurethane block is formed by the above-described production methods, and the block is formed into a sheet shape by slicing or the like, and a polishing layer containing a polyurethane resin is formed and bonded to a support or the like. And manufacturing. Alternatively, the abrasive layer may be formed directly on the support.

More specifically, the polishing layer is a polishing pad of the present invention in which a double-sided tape is attached to a side of the polishing layer opposite to the polishing surface and cut into a specific shape. The double-sided tape is not particularly limited and can be arbitrarily selected from the double-sided tape known in the art. Further, the polishing pad of the present invention may be a single layer structure composed only of a polishing layer, or may be a composite layer in which another layer (lower layer, support layer) is bonded to the surface of the polishing layer opposite to the polishing surface.

The polishing layer is formed by curing a polyurethane resin curable composition containing a polyisocyanate compound and a polyol compound, and curing the polyurethane resin curable composition.

The polishing layer contains a foamed polyurethane resin, and the foaming agent containing the micro hollow spheres can be dispersed in the polyurethane resin for foaming, in which case, by preparing a polyisocyanate compound, The polyurethane compound foaming curable composition of the polyol compound and the foaming agent is formed by foaming and curing the polyurethane resin foaming curable composition.

The polyurethane curable composition may be, for example, a two-liquid type composition obtained by mixing a liquid A containing a polyisocyanate compound and a liquid B containing a component other than the polyisocyanate compound. The liquid B containing the components other than the above may be further divided into a plurality of liquids, and a composition comprising three or more liquids may be mixed.

The polyisocyanate compound may also comprise a prepolymer prepared by the reaction of a polyisocyanate compound and a polyol compound which is commonly used in the industry. Prepolymers containing unreacted isocyanate groups are commonly used by users in the industry and can also be used in the present invention.

(isocyanate component)

Examples of the isocyanate component include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), 2,4-toluene diisocyanate (2,4-TDI), and naphthalene- 1,4-Diisocyanate, Diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-Methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethyl Oxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, Xylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propyl-1,2-diisocyanate, butyl-butyl- 1,2-diisocyanate, cyclohexyl-1,2-diisocyanate, cyclohexyl-1,4-diisocyanate, p-phenylene isothiocyanate, xylene-1,4-diisothiocyanate Ester, hypoethyl diisothiocyanate, and the like.

(polyol component)

Examples of the polyol component include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,3-butylene glycol, and 1,4-butanediol. , neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol and other glycols; polytetramethylene glycol (PTMG), polyethylene glycol, a polyether polyol such as polypropylene glycol; a polyester polyol such as a reaction product of ethylene glycol with adipic acid or a reaction product of butanediol and adipic acid; a polycarbonate polyol; a polycaprolactone polyol;

(hardener)

The hardener is a compound of a polyurethane resin which is reacted with an isocyanate group in the prepolymer when the prepolymer is used as a polyisocyanate compound. this invention Among them, for example, a curing agent described below can be exemplified.

The polyol used as the hardener is the same as the polyol component described above. Further, a triol or a trifunctional or higher polyhydric alcohol such as trifunctional glycerin may be used.

Examples of the polyamine include a diamine, and examples thereof include an alkylenediamine such as ethylenediamine, propylenediamine, and hexamethylenediamine; isophoronediamine and dicyclohexylmethane-4. 4'-diamine or the like having an aliphatic ring; 3,3'-dichloro-4,4'-diaminodiphenylmethane (alias: methylene bis-o-chloroaniline) (hereinafter referred to as MOCA) a diamine having an aromatic ring; 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, A polyamine having a hydroxyl group such as 2-hydroxypropylethylenediamine or di-2-hydroxypropylethylenediamine, particularly a hydroxyalkylalkylene diamine or the like. Further, a trifunctional triamine compound or a tetrafunctional or higher polyamine compound can also be used.

A particularly preferred hardener is the aforementioned MOCA, and the chemical structure of the MOCA is as described above. In MOCA, a tetramer is included as a by-product, and the chemical structure of the tetramer is as described above. The tetramer is contained in an amount of 3 to 10% by weight, preferably 4 to 8% by weight, and more preferably 5 to 7% by weight, based on 100% by weight of the total amount of the curing agent.

(foaming agent)

The foam can be formed by mixing a minute hollow sphere into a polyurethane resin. The micro hollow sphere is obtained by heating and expanding an unfoamed heat-expandable microsphere containing an outer shell (polymer shell) containing a thermoplastic resin and a low-boiling hydrocarbon contained in the outer shell. As the polymer shell, for example, a thermoplastic resin such as an acrylonitrile-vinylidene chloride copolymer, an acrylonitrile-methyl methacrylate copolymer, or a vinyl chloride-ethylene copolymer can be used. Similarly, as the low boiling point hydrocarbon encapsulated in the polymer shell, for example, isobutane, pentane, isopentane, petroleum ether or the like can be used.

(other ingredients)

Further, a catalyst or the like which is generally used in the industry may be added to the foaming curable composition.

[Examples]

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

(material)

List the materials used in the following examples.

‧The name of the urethane prepolymer:

ADIPRENE L325 manufactured by UNIROYAL

PANDEX C730 manufactured by DIC

NOVARETAN UP-127 manufactured by Mitsubishi Plastics Co., Ltd.

‧The trade name of MOCA (either of which contains a small amount of the above tetramer):

PANDEX E, PANDEX E50 manufactured by DIC

LM-52 Amine manufactured by IHARA CHEMICAL

‧The name of the hollow microparticles:

EXPANCEL 551DE40d42 manufactured by JAPAN FILLITE

MATSUMOTOMICROSPHERE F-80DE manufactured by Matsumoto Oil Co., Ltd.

(Example 1)

Prepared separately: Component A: NCO equivalent 460 urethane prepolymer (PANDEX C730) with toluene diisocyanate as main component, 100 g (parts), component B: PANDEX E and PANDEX E50 as hardeners by weight The mixture obtained by mixing 1:1 (containing 6.0% by weight of the hardener, containing 6.0% by weight of tetramer) 30.75 g (parts), and C component: hollow fine particles 2.25 g (parts) (EXPANCEL 551DE40d42 and MATSUMOTOMICROSPHERE) F-80DE is mixed according to 4:1). In addition, in order to express the ratio, it is described by g, and the required weight (part) is prepared according to the size of a block. Hereinafter, the description will be made in the same manner as g (parts).

Each of the component A and the component B is defoamed under reduced pressure in advance, and then the component A, the component B, and the component C are supplied to the mixer.

The resulting mixture was cast into a mold frame (square of 890 mm × 890 mm) which had been heated to 80 ° C, and after heating for 5 hours to be hardened, the formed resin foam was taken out from the mold frame. The foam was cut into a thickness of 1.3 mm to prepare a urethane sheet, and a polishing pad was obtained.

(Example 2)

Prepared separately: Component A: NCO equivalent of 400 urethane prepolymer (NOVARETAN UP-127) with toluene diisocyanate as main component, 100 g (parts), component B: PANDEX E and LM- as hardener 52 Amine mixed according to weight ratio of 7:3 (100% by weight of hardener, containing 5.0% by weight of tetramer) 30.5g (parts), C component: hollow microparticles 2.0g (parts) (will EXPANCEL 551DE40d42 and MATSUMOTOMICROSPHERE F-80DE are mixed according to 4:1).

Thereafter, a urethane sheet was produced in the same manner as in Example 1 to obtain a polishing pad.

(Comparative Example 1)

A polishing pad IC1000 manufactured by Nitta Haas Co., Ltd. was used as a comparative example.

(Comparative Example 2)

Prepared separately: Component A: NCO equivalent 460 urethane prepolymer (ADIPRENE L325) with toluene diisocyanate as the main component, 100 g (parts), component B: PANDEX E as a hardener (based on the weight of the hardener) 100 wt%, containing 2.1 wt% of tetramer) 29.8 g (part), C component: hollow microparticles (EXPANCEL 551 DE40d42) 2.1 g (parts).

Thereafter, a urethane sheet was produced in the same manner as in Example 1 to obtain a polishing pad.

(Comparative Example 3)

Prepared separately: Component A: NCO equivalent 460 urethane prepolymer (PANDEX C730) with toluene diisocyanate as main component, 100 g (parts), component B: IHARACUAMINE LM-52 Amine as hardener (hardened) The weight of the agent is 100% by weight, containing 11.8% by weight of tetramer) 31.0 g (parts), and C component: hollow fine particles (EXPANCEL 551DE40d42) 2.1g (parts).

Thereafter, a urethane sheet was produced in the same manner as in Example 1 to obtain a polishing pad.

(hardness, storage elastic modulus E', scratches)

The D hardness is measured in accordance with JIS K6253-1997/ISO 7619.

The storage elastic modulus E' (MPa) was measured by TA INSTRUMENTS JAPAN RSAIII at 40 ° C according to JIS K7244-4 under the conditions of an initial load of 10 g, a deformation range of 0.01 to 4%, and a measurement frequency of 0.2 Hz. It was measured at 40 ° C during drying and when wet.

The dry state of the polishing pad is defined as being placed in a state of 20±2° C. and a humidity of 65±5% for 2 hours or more. The wet state of the polishing pad is defined as being immersed in deionized water of 40° C.±2 for 1 hour. The state of swelling.

The evaluation of the defects such as the scratches was performed by polishing the 25 substrates, and the five substrates of the 21st to 25th sheets after the polishing were measured by the high-sensitivity measurement mode of the wafer surface inspection device (Surfscan SP1DLS, manufactured by KLA TENCOR Co., Ltd.). The number of defects such as scratches on the surface of the substrate was evaluated. In the evaluation of defects such as scratches, it will be 12 inches (300mm) In the wafer, less than 200 defects of 0.16 μm or more are denoted by ○, and 200 or more are denoted by ×.

(grinding rate)

The conditions of the grinding test are as follows.

‧ Grinding machine used: manufactured by Ebara Seisakusho Co., Ltd., F-REX300

‧ Grinding disc: 3M A188 (# 60)

‧ number of revolutions: (platen) 70rpm, (top ring) 71rpm

‧ Grinding pressure: 3.5psi

‧ Abrasive: manufactured by CABOT, product number: SS25 (using SS25 stock solution: pure water = 1:1 mixture)

‧Abrasant temperature: 20 ° C

‧ Abrasive agent outflow: 200ml/min

‧Workpiece used (abrasive): at 12 inches A substrate of tetraethoxydecane is formed on the germanium wafer by PE-CVD (Plasma-Enhanced Chemical Vapor Deposition) to a thickness of 1 μm.

During the polishing process, the surface temperature of the polishing pad rises, and the temperature from the initial temperature of the polishing to 20 ° C becomes 40 to 50 ° C.

(analysing conditions of tetramer)

‧ Analytical machine used: Gel Permeation Chromatograph L-7200 (Hitachi)

‧column: Ohpak KB-802.5 (excluding the limit 10000) 2 series

‧Mobile phase: DMF (dimethyl formamide, dimethylformamide)

‧Flow rate: 0.4mL/min

‧Oven: 60 ° C

‧Detector: RI (Refractive Index, refractive index) 60 ° C

‧ Sample size: 90 μL

The above results are shown in Tables 1 and 2.

As shown in Table 1, it was found that the surface hardness of the polishing pad of the present invention was softened in the polishing operation using the slurry by setting the D hardness and the storage elastic modulus at the time of wetting at 40 ° C to a specific range. This softening greatly contributes to the polishing performance (reduction of scratch rate, research) Increase in grinding rate).

As shown in Table 2, it was found that the amount of the tetramer contained in the MOCA used as the curing agent greatly contributes to the polishing performance (reduction in scratch rate and improvement in polishing rate).

Using the methods and novel insights of the present invention described above, it is possible to screen for useful hardeners comprising MOCA.

(Injection test using thermomechanical analysis (TMA))

The outline of the test is shown in Fig. 1. A needle to which a certain load is applied is pressed against the polishing pad, and the temperature rise of the needle and the depth of insertion of the needle are measured. If the temperature of the needle rises while the surface of the polishing pad softens, the needle is inserted.

Follow the conditions below.

Measuring device: TMA/Q400 (manufactured by TA INSTRUMENT) INTRACOOLER cooler

Measuring method: needle insertion mode

Probe diameter: 1mm

Heating rate: 5 ° C / min

Measurement environment: nitrogen (flow: 50mL/min)

Measuring load: 50gf

Test piece size: about 5mm × about 5mm × about 1.5mm thickness

Measuring direction: compression in the thickness direction (needle in)

Pre-measurement treatment: water (10 μL) is added to the sample immediately before the measurement

The results are shown in Figures 2 to 4.

In Examples 1 and 2 (Figs. 2 and 3), the needle was temporarily inserted into the sample at around 50 ° C, and after a while, the penetration depth was approximately constant, and the needle was reinserted into the sample at around 150 ° C. The results show that in Examples 1 and 2, the surface layer portion and the inner portion have differences in chemical structure, and the softening temperature is different to reflect this.

On the other hand, in Comparative Example 1 (Fig. 4), the needle was not inserted until the vicinity of 180 °C. It is considered that there is no difference in chemical structure between the surface layer portion and the inner portion.

The above results are shown in Table 3.

The needle-in temperature of the first paragraph is defined as the inflection point of the graph of the graph, and the needle-in temperature of the second segment is defined as the point where the slope of the tangent to the curve is 1 (= 45°).

As shown in Table 3, it was found that the polishing pad of the present invention softens the surface by polishing, and the polishing performance is improved (the scratch rate is lowered and the polishing rate is increased).

Claims (9)

A polishing pad characterized in that it has an abrasive layer comprising a polyurethane resin, and the polishing layer is a polyamine group containing a polyisocyanate compound, a polyol compound, a hardener, and a micro hollow sphere. The acid ester resin curable composition is formed by curing, and has the following formula: {(D hardness of the polishing pad in a dry state) - (D hardness of the polishing pad which is swollen by warm water at 40 ° C)} / (dry state) The D hardness of the polishing pad is 0.1 to 0.3, and the following formula: {(the storage elastic modulus of the polishing pad in a dry state) - (the storage elastic modulus of the polishing pad saturated with warm water at 40 ° C)} / (The storage elastic modulus of the polishing pad in a dry state) has a value of 0.4 to 0.7. A polishing pad characterized by comprising a polishing layer comprising a polyurethane resin, the polishing layer comprising a polyisocyanate compound, a polyol compound, and a 3,3'-dichloro-4,4 The hardening agent of '-diaminodiphenylmethane and the hardening composition of the micro hollow spheres are formed by hardening, and the above 3,3'-dichloro-4,4'-diamine The diphenylmethane contains 3 to 10% by weight of a tetramer. A polishing pad characterized by comprising a polishing layer comprising a polyurethane resin, wherein the polishing layer comprises a polyisocyanate compound, a polyol compound, and a hard The chemical agent and the urethane composition of the micro hollow spheres are formed by curing, and at least have a surface layer portion which softens during wet grinding. The polishing pad of claim 3, wherein the thickness of the surface portion is 50 μm or less. The polishing pad of claim 3, wherein the thickness of the surface portion is smaller than the diameter of the minute hollow sphere. The polishing pad of claim 3, wherein in the needle insertion test by thermomechanical analysis (TMA), the needle insertion temperature of the first stage is 50 to 100 ° C, and the needle insertion temperature of the second stage is 150 ° C or more. The polishing pad according to any one of claims 1 to 6, wherein the polyisocyanate compound and the polyol compound comprise a prepolymer prepared by reacting a polyisocyanate compound with a polyol compound. A method of grinding, which is a method of grinding a surface of an optical material or a semiconductor material, and using the polishing pad of any one of claims 1 to 6. A method of reducing scratches when polishing an optical material or a surface of a semiconductor material, using the polishing pad according to any one of claims 1 to 6 to reduce scratches when polishing the surface of the optical material or the semiconductor material.