KR102283399B1 - Composition for polishing pad, polishing pad and preparation method thereof - Google Patents

Abstract

In the composition according to the embodiment, the composition of the oligomers constituting the chain in the urethane-based prepolymer may be adjusted to control physical properties such as gelation time. Therefore, since the polishing pad obtained by curing the composition according to the embodiment can control the fine pore characteristics, the polishing rate, and the pad cutting rate, it is possible to efficiently manufacture a high-quality semiconductor device using the polishing pad.

Description

A composition for a polishing pad, a polishing pad, and a manufacturing method thereof

Embodiments relate to a composition for a porous polyurethane polishing pad that can be used in a chemical mechanical planarization (CMP) process of a semiconductor, a porous polyurethane polishing pad, and a method of manufacturing the same.

In the chemical mechanical planarization (CMP) process of the semiconductor manufacturing process, in a state where a wafer is attached to a head and brought into contact with the surface of a polishing pad formed on a platen, slurry is supplied to chemically prepare the wafer surface. It is a process of mechanically flattening the uneven part of the wafer surface by moving the platen and the head relative to each other while reacting.

The polishing pad is an essential raw material that plays an important role in the CMP process, and is generally made of a polyurethane resin, and the polyurethane resin includes a prepolymer obtained by reacting a diisocyanate monomer with a polyol, a curing agent, a foaming agent, etc. do.

In addition, the polishing pad has a surface on the surface of which a groove is responsible for a large flow of the slurry and a pore that supports a fine flow. It is formed by forming a gas, or by generating a gas by a chemical reaction.

Korean Patent Publication No. 2016-0027075

The urethane-based prepolymer used to manufacture the polishing pad has different properties depending on the monomer, which greatly affects the performance of the chemical mechanical planarization (CMP) process. Therefore, controlling the composition and physical properties of the urethane-based prepolymer is very important in controlling the performance of the polishing pad.

As a result of research by the present inventors, the gelation time changes depending on the composition of the oligomers constituting the chains in the urethane-based prepolymer, and accordingly, the elongation and the pore diameter of the polishing pad change, thereby affecting the CMP performance such as the polishing rate. found it In particular, the present inventors paid attention to the composition of oligomers produced by the reaction of an aromatic diisocyanate monomer and a polyol used in the preparation of a urethane-based prepolymer.

Accordingly, embodiments provide a composition in which physical properties are controlled by controlling the composition of oligomers constituting a chain in the urethane-based prepolymer, a method for preparing the composition, a method for manufacturing a polishing pad using the composition, a polishing pad obtained from the composition, and the polishing An object of the present invention is to provide a method for manufacturing a semiconductor using a pad.

According to one embodiment, it includes a urethane-based prepolymer, a curing agent, and a foaming agent, and includes a urethane-based prepolymer, a curing agent, and a foaming agent, wherein the urethane-based prepolymer includes a first oligomer in which n is 0 or 1 in the following Chemical Formula 1; and a second oligomer wherein n is 2 or 3 in Formula 1 below.

[Formula 1]

According to another embodiment, preparing a first oligomer in which n is 0 or 1 in Formula 1; preparing a second oligomer in which n is 2 or 3 in Formula 1; preparing a urethane-based prepolymer including the first oligomer and the second oligomer; and mixing the urethane-based prepolymer, a curing agent, and a foaming agent, a method for preparing a composition is provided.

According to another embodiment, preparing a first raw material composition comprising a urethane-based prepolymer; preparing a second raw material composition including a curing agent; Preparing a third raw material composition comprising a foaming agent; preparing a raw material mixture by sequentially or simultaneously mixing the first raw material composition with the second raw material composition and the third raw material composition; and injecting the raw material mixture into a mold and curing the mixture, wherein the urethane-based prepolymer has the same configuration as the urethane-based prepolymer included in the composition according to an embodiment above, a method of manufacturing a polishing pad is provided.

According to another embodiment, it includes a polyurethane resin and a plurality of fine pores dispersed in the polyurethane resin, wherein the polyurethane resin is derived from a urethane-based prepolymer, and the urethane-based prepolymer according to an embodiment A polishing pad having the same composition as the urethane-based prepolymer included in the composition is provided.

According to another embodiment, comprising the step of polishing the surface of the wafer using a polishing pad, the polishing pad comprises a polyurethane resin and a plurality of fine pores dispersed in the polyurethane resin, the polyurethane resin is derived from a urethane-based prepolymer, and the urethane-based prepolymer has the same configuration as the urethane-based prepolymer included in the composition according to an embodiment above, a method for manufacturing a semiconductor device is provided.

In the composition according to the embodiment, the composition of the oligomers constituting the chain in the urethane-based prepolymer may be adjusted to control physical properties such as gelation time. Therefore, since the polishing pad obtained by curing the composition according to the embodiment can control the fine pore characteristics, the polishing rate, and the pad cutting rate, it is possible to efficiently manufacture a high-quality semiconductor device using the polishing pad.

1, 2 and 3 show the results of matrix-assisted laser desorption/ionization (MALDI) analysis of the urethane-based prepolymers prepared in Examples 1, 2 and Comparative Example 1, respectively.
4A, 4B and 4C are scanning electron microscope (SEM) images of pores of a polishing pad obtained by curing the compositions of Examples 1, 2 and Comparative Example 1, respectively.
5 shows the removal rates of the polishing pads of Examples 1, 2 and Comparative Example 1. FIG.
6 shows the pad cut rates of the polishing pads of Examples 1, 2 and Comparative Example 1. FIG.

In the following description of embodiments, in the case where each layer, pad or sheet, etc. is described as being formed "on" or "under" each layer, pad or sheet, etc., "on ( “on” and “under” include both “directly” or “indirectly through” other elements.

In addition, the reference for the upper / lower of each component will be described with reference to the drawings. The size of each component in the drawings may be exaggerated for explanation, and does not mean the size actually applied.

In addition, it should be understood that all numerical ranges indicating physical property values, dimensions, etc. of the components described in the present specification are modified by the term "about" in all cases unless otherwise specified.

[Composition for polishing pad]

The composition according to an embodiment includes a urethane-based prepolymer, a curing agent, and a foaming agent. Hereinafter, each component will be described in detail.

Urethane-based prepolymer

A prepolymer generally refers to a polymer having a relatively low molecular weight in which the polymerization degree is stopped at an intermediate stage to facilitate molding in the production of a final molded article. For example, the weight average molecular weight (Mw) of the urethane-based prepolymer may be 500 g/mol to 3,000 g/mol, 600 g/mol to 2,000 g/mol, or 700 g/mol to 1,500 g/mol. The prepolymer can be formed into a final product on its own or after further reaction with other polymerizable compounds or curing agents.

The urethane-based prepolymer may be a prepolymerization product of at least one diisocyanate monomer and at least one polyol.

The one or more diisocyanate monomers may be one or more aromatic diisocyanate monomers and/or one or more aliphatic diisocyanate monomers, for example, toluene diisocyanate (TDI), naphthalene-1,5-di Isocyanate (naphthalene-1,5-diisocyanate), para-phenylene diisocyanate (p-phenylene diisocyanate), tolidine diisocyanate, diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate ( It may be one or more isocyanates selected from the group consisting of hexamethylene diisocyanate, HDI), dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate, and the like.

As a specific example, the at least one diisocyanate monomer comprises at least one aromatic diisocyanate monomer, and the at least one aromatic diisocyanate monomer comprises toluene 2,4-diisocyanate and toluene 2,6-diisocyanate. can

As another specific example, the one or more diisocyanate monomers further include one or more aliphatic diisocyanate monomers, and the one or more aliphatic diisocyanate monomers include diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI). , dicyclohexylmethane diisocyanate (H12MDI), and the like.

The polyol refers to a compound having two or more hydroxyl groups, and may include a monomolecular polyol and a high molecular polyol.

Examples of the monomolecular polyol include ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), propanediol (PDO), methyl propanediol (MP-diol), and the like, and the polymer type Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, and the like. The high molecular weight polyol may have a weight average molecular weight of 300 g/mol to 3,000 g/mol.

As a specific example, the polyol may include diethylene glycol (DEG) and polytetramethylene ether glycol (PTMEG).

Chain composition in the prepolymer

The urethane-based prepolymer includes a polymerization reaction product of various molecular weights between a diisocyanate monomer and a polyol.

Specifically, the urethane-based prepolymer includes oligomers of various molecular weights between an aromatic diisocyanate monomer and a polyol.

More specifically, the urethane-based prepolymer includes oligomers of various molecular weights between toluene diisocyanate (TDI) and diethylene glycol (DEG).

The urethane-based prepolymer included in the composition according to the embodiment may include a first oligomer in which n is 0 or 1 in the following Chemical Formula 1; and a second oligomer in which n is 2 or 3 in Formula 1 below.

[Formula 1]

For example, the urethane-based prepolymer may include the first oligomer and the second oligomer in a weight ratio of 1:0.1 to 1:10, a weight ratio of 1:0.2 to 1:5, a weight ratio of 1:0.5 to 1:2, or It may be included in a weight ratio of 1:0.6 to 1:1.5.

As a specific example, the urethane-based prepolymer may include the first oligomer and the second oligomer in a weight ratio of 1:0.2 to 1:5.

In addition, the urethane-based prepolymer may further include a third oligomer in which n is an integer of 4 to 6 in Formula 1 above.

For example, the urethane-based prepolymer may include the first oligomer, the second oligomer, and the third oligomer in a weight ratio of 1:0.1:0.1 to 1:10:10, and 1:0.2:0.2 to 1:5:5. It may be included in a weight ratio of 1:0.5:0.5 to 1:2:2, or in a weight ratio of 1:0.6:0.6 to 1:1.5:1.5.

As a specific example, the urethane-based prepolymer may include the first oligomer, the second oligomer, and the third oligomer in a weight ratio of 1:0.2:0.1 to 1:5:10.

The first oligomer may be an oligomer in which n is 0 in Formula 1, an oligomer in which n is 1, or a mixture thereof.

The second oligomer may be an oligomer in which n is 2 in Formula 1, an oligomer in which n is 3, or a mixture thereof.

In Formula 1, the third oligomer may be an oligomer in which n is 4, an oligomer in which n is 5, an oligomer in which n is 6, or a mixture of at least two thereof.

Accordingly, a composition including the first oligomer, the second oligomer, and the third oligomer may have various compositions.

As an example, the composition may include at least one of an oligomer in which n is 0 and an oligomer in which n is 1 in Formula 1, and at least one of an oligomer in which n is 2 and an oligomer in which n is 3 in Formula 1 .

As another example, the composition may include at least one of an oligomer in which n is 0 and an oligomer in which n is 1 in Chemical Formula 1, at least one of an oligomer in which n is 2 and an oligomer in which n is 3 in Chemical Formula 1, and Chemical Formula 1 In may include at least one of an oligomer in which n is 4, an oligomer in which n is 5, and an oligomer in which n is 6.

As another example, in Formula 1, the composition may include an oligomer in which n is 0, an oligomer in which n is 1, and an oligomer in which n is 2.

As another example, in Formula 1, the composition may include an oligomer in which n is 0, an oligomer in which n is 1, an oligomer in which n is 2, and an oligomer in which n is 3.

As another example, in Formula 1, the composition may include an oligomer in which n is 0, an oligomer in which n is 1, an oligomer in which n is 2, an oligomer in which n is 3, and an oligomer in which n is 4.

As another example, in Formula 1, the composition may include an oligomer in which n is 0, an oligomer in which n is 1, an oligomer in which n is 2, an oligomer in which n is 3, an oligomer in which n is 4, and an oligomer in which n is 5. can

As another example, in Formula 1, the composition includes an oligomer in which n is 0, an oligomer in which n is 1, an oligomer in which n is 2, an oligomer in which n is 3, an oligomer in which n is 4, an oligomer in which n is 5, and n is 6 oligomers.

The urethane-based prepolymer included in the composition according to the embodiment may further include a compound represented by Formula 2 below.

[Formula 2]

In Formula 2, p is an integer of 5 to 30.

Alternatively, p may be an integer of 1 to 100, 3 to 50, or 10 to 20.

Reacted diisocyanate monomer

In the urethane-based prepolymer, the diisocyanate monomer may constitute a chain in the prepolymer by urethane-reacting at least one NCO group (ie, urethane-reacting two NCO groups or urethane-reacting one NCO group).

In the present specification, the urethane reaction means that the NCO group of the diisocyanate monomer reacts with the OH group of the polyol to form a urethane group and is connected.

In particular, the one or more diisocyanate monomers used in the preparation of the urethane-based prepolymer include one or more aromatic diisocyanate monomers, and the one or more aromatic diisocyanate monomers may participate in the prepolymerization reaction at a high ratio.

For example, the urethane-based prepolymer may contain, based on the total weight of the one or more aromatic diisocyanate monomers, the aromatic diisocyanate monomer in which at least one NCO group has been urethane-reacted from 50 wt% to 99 wt%, from 60 wt% to 99 wt%, 70 wt% to 99 wt%, 80 wt% to 99 wt%, or 90 wt% to 99 wt% may be included.

In particular, the urethane-based prepolymer is, based on the total weight of the at least one aromatic diisocyanate monomer, 10% to 40% by weight of the aromatic diisocyanate monomer in which two NCO groups are urethane-reacted, 10% to 35% by weight , 15 wt% to 35 wt%, 20 wt% to 35 wt%, 10 wt% to 30 wt%, 20 wt% to 30 wt%, 15 wt% to 25 wt%, or 10 wt% to 25 wt% may include

In addition, the urethane-based prepolymer, based on the total weight of the at least one aromatic diisocyanate monomer, 50% to 90% by weight of the aromatic diisocyanate monomer in which one NCO group is urethane-reacted, 60% to 90% by weight , 70% to 90% by weight, 80% to 90% by weight, 50% to 80% by weight, or 60% to 80% by weight may be included.

At this time, the urethane-based prepolymer is an aromatic diisocyanate monomer in which the two NCO groups are urethane-reacted, and the aromatic diisocyanate monomer in which the two NCO groups are urethane-reacted in a weight ratio of 0.1:1 to 1:1, 0.2:1 to 1:1 of, a weight ratio of 0.2:1 to 0.5:1, a weight ratio of 0.3:1 to 1:1, or a weight ratio of 0.3:1 to 0.5:1.

More specifically, the one or more aromatic diisocyanate monomers may include toluene 2,4-diisocyanate and toluene 2,6-diisocyanate, wherein the urethane-based prepolymer is a total of the one or more aromatic diisocyanate monomers. Based on the weight, toluene 2,4-diisocyanate in which at least one NCO group has been urethane-reacted and toluene 2,6-diisocyanate in which at least one NCO group has been urethane-reacted, total 90% to 98% by weight, 93% by weight to 98% by weight, or 95% to 98% by weight.

In addition, the urethane-based prepolymer is, based on the total weight of the at least one aromatic diisocyanate monomer, toluene 2,4-diisocyanate in which two NCO groups are urethane-reacted from 10 wt% to 40 wt%, 10 wt% to 35% by weight, 15% to 35% by weight, 20% to 35% by weight, 10% to 30% by weight, 20% to 30% by weight, or 10% to 25% by weight.

In addition, the urethane-based prepolymer is, based on the total weight of the at least one aromatic diisocyanate monomer, 40 wt% to 80 wt%, 45 wt% to 45 wt% of toluene 2,4-diisocyanate in which one NCO group is urethane-reacted 75% by weight, 45% to 70% by weight, 50% to 65% by weight, 45% to 65% by weight, 45% to 60% by weight, 60% to 75% by weight, or 60% to 70% by weight It may be included in weight %.

In addition, the urethane-based prepolymer, based on the total weight of the at least one aromatic diisocyanate monomer, 1 wt% to 30 wt% of toluene 2,6-diisocyanate in which one NCO group is urethane-reacted, 5 wt% to 25% by weight, 10% to 25% by weight, 10% to 20% by weight, 5% to 20% by weight, 5% to 15% by weight, or 10% to 15% by weight.

unreacted diisocyanate monomer

In addition, some of the compounds used in the reaction for preparing the urethane-based prepolymer may not participate in the reaction.

Accordingly, there may be a compound that remains uninvolved in the reaction in the urethane-based prepolymer.

Specifically, the urethane-based prepolymer may include an unreacted diisocyanate monomer. As used herein, the term 'unreacted diisocyanate monomer' refers to a diisocyanate monomer in which both NCO groups remain unreacted.

The urethane-based prepolymer is, based on the weight of the urethane-based prepolymer, 7 wt% to 10 wt%, 7 wt% to 9 wt%, 7 wt% to 8 wt%, 8 wt% of unreacted diisocyanate monomer to 10 wt%, 9 wt% to 10 wt%, 8 wt% to 9 wt% may be included.

The unreacted diisocyanate monomer present in the urethane-based prepolymer may include an unreacted aromatic diisocyanate monomer.

For example, the urethane-based prepolymer may contain, based on the weight of the urethane-based prepolymer, unreacted aromatic diisocyanate monomer in an amount of 0.1 wt% to 5 wt%, 0.1 wt% to 3 wt%, 0.1 wt% to 2.3 wt% %, 0.1 wt% to 1.5 wt%, 0.1 wt% to 1 wt%, 0.5 wt% to 2 wt%, 1 wt% to 2 wt% may be included.

As a specific example, the urethane-based prepolymer may include an unreacted aromatic diisocyanate monomer in an amount of 0.1 wt% to 3 wt%, based on the weight of the urethane-based prepolymer.

When one or more aromatic diisocyanate monomers used in the reaction of the urethane-based prepolymer include toluene 2,4-diisocyanate and toluene 2,6-diisocyanate, among them, toluene 2,6-diisocyanate is relatively reactive Since this is low, it may be present in the urethane-based prepolymer without reacting with the polyol.

For example, the urethane-based prepolymer may contain, based on the weight of the urethane-based prepolymer, unreacted toluene 2,6-diisocyanate in an amount of 0.1 wt% to 10 wt%, 0.1 wt% to 8 wt%, 0.1 wt% to 6 wt%, 0.1 wt% to 4 wt%, 0.1 wt% to 3 wt%, 0.5 wt% to 4 wt%, or 1 wt% to 4 wt% may be included.

In addition, the unreacted diisocyanate monomer present in the urethane-based prepolymer may include an unreacted aliphatic diisocyanate monomer.

For example, the urethane-based prepolymer may contain 1 wt% to 20 wt%, 1 wt% to 15 wt%, 1 wt% to 10 wt% of the unreacted aliphatic diisocyanate monomer, based on the weight of the urethane-based prepolymer. %, 5 wt% to 20 wt%, 10 wt% to 20 wt%, or 5 wt% to 15 wt%.

In addition, the urethane-based prepolymer includes an unreacted aromatic diisocyanate monomer and an unreacted aliphatic diisocyanate monomer in a weight ratio of 0.01:1 to 1:1, a weight ratio of 0.05:1 to 0.8:1, and 0.05:1 to 0.7:1 of, a weight ratio of 0.05:1 to 0.5:1, or a weight ratio of 0.05:1 to 0.3:1.

Unreacted NCO group content

The urethane-based prepolymer may have an unreacted NCO group at the end of the polymer, oligomer or monomer included therein.

For example, the urethane-based prepolymer may include, based on the weight of the urethane-based prepolymer, 5 wt% to 15 wt%, 5 wt% to 13 wt%, 8 wt% to 10 wt%, 9 of unreacted NCO groups It may be included in an amount of 10% by weight to 10% by weight, 7% to 9% by weight, or 7% to 8% by weight.

As a specific example, the urethane-based prepolymer may include 7 wt% to 10 wt% of unreacted NCO groups based on the weight of the urethane-based prepolymer. In this case, the urethane-based prepolymer may include 1 wt% to 3 wt% of the unreacted aromatic diisocyanate monomer based on the weight of the urethane-based prepolymer. In addition, at this time, the composition may have a gelation time of 100 seconds to 115 seconds.

hardener

The curing agent may be at least one of an amine compound and an alcohol compound. Specifically, the curing agent may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

For example, the curing agent is 4,4'-methylenebis (2-chloroaniline) (MOCA), diethyltoluenediamine (DETDA), diaminodiphenyl methane (diaminodiphenyl methane), diaminodiphenyl sulfone ( diaminodiphenyl sulphone), m-xylylene diamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine ), polypropylenetriamine, ethyleneglycol, diethyleneglycol, dipropyleneglycol, butanediol, hexanediol, glycerine, trimethylolpropane ( trimethylolpropane) and bis(4-amino-3-chlorophenyl)methane may be at least one selected from the group consisting of bis(4-amino-3-chlorophenyl)methane.

The urethane-based prepolymer and the curing agent may be mixed in a molar equivalent ratio of 1:0.8 to 1:1.2, or a molar equivalent ratio of 1:0.9 to 1:1.1, based on the number of moles of reactive groups in each molecule. . Here, "based on the number of moles of each reactive group" means, for example, based on the number of moles of isocyanate groups of the urethane-based prepolymer and the number of moles of reactive groups (amine groups, alcohol groups, etc.) of the curing agent. Therefore, the urethane-based prepolymer and the curing agent may be added at a constant rate in the mixing process by controlling the input rate to be added per unit time in amounts satisfying the molar equivalent ratio exemplified above.

blowing agent

The foaming agent is not particularly limited as long as it is commonly used to form pores of the polishing pad.

For example, the foaming agent may be at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and an inert gas.

The solid foaming agent may be a microcapsule whose size is adjusted by thermal expansion (hereinafter, referred to as 'thermal-expanded microcapsule'). The thermally expanded microcapsules may be obtained by heating and expanding the thermally expandable microcapsules. The thermally expanded microcapsule is a structure of an already expanded microballoon, and has the advantage of uniformly controlling the particle size of the pores by having a uniform particle size. Specifically, the solid foaming agent may be a micro-balloon structure having an average particle diameter of 5 μm to 200 μm.

The thermally expandable microcapsules may include: a shell including a thermoplastic resin; And it may include a foaming agent encapsulated inside the shell. The thermoplastic resin may be at least one selected from the group consisting of a vinylidene chloride-based copolymer, an acrylonitrile-based copolymer, a methacrylonitrile-based copolymer, and an acrylic copolymer. Further, the blowing agent may be at least one selected from the group consisting of hydrocarbons having 1 to 7 carbon atoms.

The solid foaming agent may be used in an amount of 0.1 parts by weight to 2.0 parts by weight based on 100 parts by weight of the urethane-based prepolymer. Specifically, the solid foaming agent may be used in an amount of 0.3 parts by weight to 1.5 parts by weight, or 0.5 parts by weight to 1.0 parts by weight based on 100 parts by weight of the urethane-based prepolymer.

The type of the inert gas is not particularly limited as long as it does not participate in the reaction between the urethane-based prepolymer and the curing agent. For example, the inert gas _{may be at least one selected from the group consisting of nitrogen gas (N 2} ), carbon dioxide gas (CO ₂ ), argon gas (Ar), and helium (He). Specifically, the inert gas may be nitrogen gas (N ₂ ) or carbon dioxide gas (CO ₂ ).

The inert gas may be introduced in a volume corresponding to 10% to 30% of the total volume of the polyurethane composition. Specifically, the inert gas may be input in a volume corresponding to 15% to 30% of the total volume of the polyurethane composition.

gelation time

The composition takes a certain amount of time to gel by curing, which is referred to as gel time.

The gelation time of the composition may be at least 50 seconds, at least 70 seconds, at least 80 seconds, or at least 100 seconds. For example, the gelation time of the composition may be 50 seconds to 200 seconds, 50 seconds to 150 seconds, 50 seconds to 100 seconds, 100 seconds to 200 seconds, or 150 seconds to 200 seconds. As a specific example, the composition may have a gelation time of 80 seconds to 130 seconds.

The gelation time may be, for example, a value measured at 70°C.

Characteristics after curing

The composition may have mechanical properties such as tensile strength, elongation, hardness and the like after curing in a specific range.

For example, the tensile strength after curing of the composition is 5 N/mm ² to 30 N/mm ² , 10 N/mm ² to 25 N/mm ² , 10 N/mm ² to 20 N/mm ² , or 15 N /mm ² to 30 N/mm ² It may be.

In addition, the elongation after curing of the composition may be 50% to 300%, 100% to 300%, 150% to 250%, or 100% to 200%.

In addition, the hardness of the composition after curing is 30 Shore D to 80 Shore D, 40 Shore D to 70 Shore D, 50 Shore D to 70 Shore D, 40 Shore D to 60 Shore D, or 50 Shore D to 60 Shore D days. can

As a specific example, the composition may have ^{a tensile strength of 10 N/mm 2} to 23 N/mm ² after curing, an elongation of 80% to 250%, and a hardness of 40 Shore D to 65 Shore D.

The composition may have a plurality of micropores after curing.

The average size of the micropores may be 10 μm to 50 μm, 20 μm to 50 μm, 20 μm to 40 μm, 20 μm to 30 μm, or 30 μm to 50 μm.

In addition, the composition has a removal rate after curing of 3,000 Å/50 sec to 5,000 Å/50 sec, 3,000 Å/50 sec to 4,000 Å/50 sec, 4,000 Å/50 sec to 5,000 Å/50 sec, or 3,500 Å/50 sec to 4,500 Å/50 sec.

In addition, the composition has a pad cut rate after curing of 30 µm/hr to 60 µm/hr, 30 µm/hr to 50 µm/hr, 40 µm/hr to 60 µm/hr, 40 µm/hr to 50 μm/hr.

[Method for preparing the composition]

A method of preparing a composition according to an embodiment includes preparing a first oligomer in which n is 0 or 1 in Formula 1; preparing a second oligomer in which n is 2 or 3 in Formula 1; preparing a urethane-based prepolymer including the first oligomer and the second oligomer; and mixing the urethane-based prepolymer, a curing agent, and a foaming agent.

The step of preparing the first oligomer and the second oligomer is performed by reacting one or more diisocyanate monomers with one or more polyols, and by controlling reaction conditions such as a reaction equivalent ratio and reaction time, the first oligomer and the A second oligomer can be obtained. Alternatively, after preparing a prepolymer having oligomers of various molecular weights, the first oligomer and the second oligomer may be obtained by purification.

The step of preparing the urethane-based prepolymer including the first oligomer and the second oligomer may be performed simultaneously with or in connection with the step of preparing the first oligomer and the second oligomer. Alternatively, the urethane-based prepolymer may be obtained by first preparing the first oligomer and the second oligomer and then mixing them.

Thereafter, the urethane-based prepolymer may be mixed with a curing agent and a foaming agent to obtain a composition.

For example, it may be prepared by first mixing the urethane-based prepolymer, curing agent, foaming agent and additives in a stirrer, and then adding a photoinitiator. At this time, the stirring may be performed at 1,000 rpm to 10,000 rpm, or 4,000 rpm to 7,000 rpm.

[Manufacturing method of abrasive pad]

A method of manufacturing a polishing pad according to an embodiment includes molding while curing the composition according to the embodiment.

That is, the method of manufacturing a polishing pad according to an embodiment includes the steps of preparing a first raw material composition including a urethane-based prepolymer; preparing a second raw material composition including a curing agent; Preparing a third raw material composition comprising a foaming agent; preparing a raw material mixture by sequentially or simultaneously mixing the first raw material composition with the second raw material composition and the third raw material composition; and injecting the raw material mixture into a mold and curing the mixture, wherein the urethane-based prepolymer includes: a first oligomer in which n is 0 or 1 in the following Chemical Formula 1; and a second oligomer in which n is 2 or 3 in Formula 1 below.

[Formula 1]

Specifically, preparing the raw material mixture may include mixing the first raw material composition with the second raw material composition and then further mixing the third raw material composition, or mixing the first raw material composition with the third raw material composition. After mixing, it may be further mixed with the second raw material composition.

In addition, the step of preparing the raw material mixture may be performed at 50° C. to 150° C. conditions, and, if necessary, may be performed under vacuum defoaming conditions.

The step of hardening by injecting the raw material mixture into the mold may be performed under a ^{temperature condition of 60° C. to 120° C. and a pressure condition of 50 kg/m 2} to 200 kg/m ^{2 .}

In addition, the manufacturing method may further include a process of cutting the surface of the obtained polishing pad, a process of processing a groove on the surface, an adhesion process with a lower layer, an inspection process, a packaging process, and the like. These processes may be performed in the manner of a conventional polishing pad manufacturing method.

[polishing pad]

The polishing pad according to an embodiment includes a cured product of the composition according to the embodiment and a plurality of fine pores dispersed in the cured product.

That is, the polishing pad according to an embodiment includes a polyurethane resin and a plurality of micropores dispersed in the polyurethane resin, the polyurethane resin is derived from a urethane-based prepolymer, and the urethane-based prepolymer has the following formula a first oligomer in which 1 to n is 0 or 1; and a second oligomer in which n is 2 or 3 in Formula 1 below.

[Formula 1]

The polishing pad is made of a polyurethane resin, and the polyurethane resin may include a cured product (polymer) of a urethane-based prepolymer having an isocyanate end group. The weight average molecular weight (Mw) of the polyurethane resin is 500 g/mol to 1,000,000 g/mol, 5,000 g/mol to 1,000,000 g/mol, 50,000 g/mol to 1,000,000 g/mol, 100,000 g/mol to 700,000 g/mol mol, or from 500 g/mol to 3,000 g/mol.

The thickness of the polishing pad may be 0.8 mm to 5.0 mm, 1.0 mm to 4.0 mm, 1.0 mm to 3.0 mm, 1.5 mm to 2.5 mm, 1.7 mm to 2.3 mm, or 2.0 mm to 2.1 mm. When it is within the above range, it is possible to sufficiently exhibit basic physical properties as a polishing pad while minimizing the deviation of the particle size for each upper and lower part of the pores.

The specific gravity of the polishing pad may be 0.6 g/cm 3 to 0.9 g/cm 3 , or 0.7 g/cm 3 to 0.85 g/cm 3 .

In addition, the polishing pad may have the same physical properties and pore properties that the composition according to the embodiment has after curing, in addition to the physical properties exemplified above.

The hardness of the polishing pad may be 30 Shore D to 80 Shore D, 40 Shore D to 70 Shore D, 50 Shore D to 70 Shore D, 40 Shore D to 60 Shore D, or 50 Shore D to 60 Shore D.

The tensile strength of the polishing pad is 5 N/mm ² to 30 N/mm ² , 10 N/mm ² to 25 N/mm ² , 10 N/mm ² to 20 N/mm ² , or 15 N/mm ² to It may be 30 N/mm ^{2 .}

The elongation of the polishing pad may be 50% to 300%, 100% to 300%, 150% to 250%, or 100% to 200%.

The micropores are dispersed in the polyurethane resin.

The average size of the micropores may be 10 μm to 50 μm, 20 μm to 50 μm, 20 μm to 40 μm, 20 μm to 30 μm, or 30 μm to 50 μm. As a specific example, the micropores may have an average size of 21 μm to 25 μm.

In addition, the micropores may be included in the number of 100 to 300, 150 to 300, or 100 to 250 per ^{0.3 cm 2 area of the polishing pad.}

In addition, the total area of the micropores may be 30% to 60%, 35% to 50%, or 35% to 43% based on the total area of the polishing pad.

In addition, the micropores may be included in an amount of 30% by volume to 70% by volume, or 40% by volume to 60% by volume based on the total volume of the polishing pad.

A removal rate of the polishing pad is 3,000 Å/50 sec to 5,000 Å/50 sec, 3,000 Å/50 sec to 4,000 Å/50 sec, 4,000 Å/50 sec to 5,000 Å/50 sec, or 3,500 Å /50 sec to 4,500 Å/50 sec. As a specific example, the polishing pad may have a removal rate of 3,500 Å/50 sec to 3,900 Å/50 sec. The polishing rate may be an initial polishing rate immediately after curing (ie, immediately after manufacturing) of the polishing pad. When the initial polishing rate is within the above preferred range, it is advantageous to suppress a pad glazing phenomenon and to maintain an excellent polishing rate at an appropriate level in subsequent repeated polishing processes.

In addition, the pad cut rate of the polishing pad is 30 μm/hr to 60 μm/hr, 30 μm/hr to 50 μm/hr, 40 μm/hr to 60 μm/hr, 40 μm/hr to 50 μm/hr.

The polishing pad may have a groove on its surface for mechanical polishing. The groove may have an appropriate depth, width and spacing for mechanical polishing, and is not particularly limited.

A polishing pad according to another exemplary embodiment may include an upper pad and a lower pad, wherein the upper pad may have the same composition and physical properties as the polishing pad according to the exemplary embodiment.

The lower pad serves to absorb and disperse an impact applied to the upper pad while supporting the upper pad. The lower pad may include a nonwoven fabric or suede.

In addition, an adhesive layer may be inserted between the upper pad and the lower pad.

The adhesive layer may include a hot melt adhesive. The hot melt adhesive may be at least one selected from the group consisting of a polyurethane-based resin, a polyester-based resin, an ethylene-vinyl acetate-based resin, a polyamide-based resin, and a polyolefin-based resin. Specifically, the hot melt adhesive may be at least one selected from the group consisting of a polyurethane-based resin and a polyester-based resin.

[Method for manufacturing semiconductor device]

A method of manufacturing a semiconductor device according to an embodiment includes polishing a surface of a wafer using the polishing pad according to the embodiment.

That is, the method of manufacturing a semiconductor device according to an embodiment includes polishing the surface of the wafer using a polishing pad, wherein the polishing pad is a polyurethane resin and a plurality of fine pores dispersed in the polyurethane resin. Including, wherein the polyurethane resin is derived from a urethane-based prepolymer, the urethane-based prepolymer is a first oligomer in which n is 0 or 1 in the following Chemical Formula 1; and a second oligomer in which n is 2 or 3 in Formula 1 below.

[Formula 1]

Specifically, after the polishing pad according to the embodiment is adhered to the surface plate, a wafer is placed on the polishing pad. At this time, the surface of the wafer is in direct contact with the polishing surface of the polishing pad. A polishing slurry may be sprayed onto the polishing pad for polishing. Thereafter, the wafer and the polishing pad may be rotated relative to each other, so that the surface of the wafer may be polished.

The polishing pad according to the embodiment is obtained by curing a urethane-based prepolymer with a controlled composition and thus has excellent elongation, hardness, fine pore properties, polishing rate, etc. can be manufactured.

[Example]

It will be described in more detail through the following examples, but is not limited to the scope of these examples.

Examples and Comparative Examples

Toluene 2,4-diisocyanate (2,4-TDI), toluene 2,6-diisocyanate (2,6-TDI), polytetramethylene ether glycol (PTMEG) and dicyclohexylmethane diisocyanate (H12MDI) 4 It was put into a sphere flask and reacted at 80° C., and diethylene glycol (DEG) was further added to further react at 80° C., followed by purification to prepare reactants of various molecular weights and urethane-based prepolymers containing them.

A casting apparatus equipped with a tank and an input line for supplying raw materials such as a prepolymer, a curing agent, an inert gas, and a foaming agent, respectively, was prepared. The previously prepared urethane-based prepolymer, curing agent (bis(4-amino-3-chlorophenyl)methane, Ishihara Corporation), inert gas (N ₂ ), liquid foaming agent (FC3283, 3M Corporation), solid foaming agent (Akzonobel Corporation) and silicone-based Surfactant (Evonik) was charged to each tank. Through each input line, the raw material was added to the mixing head at a constant speed while stirring. At this time, the prepolymer and the curing agent were added in an equivalent ratio of 1:1 and a total amount of 10 kg/min.

The stirred raw material was discharged to a mold (1,000 mm x 1,000 mm x 3 mm) and the reaction was completed to obtain a solid cake-shaped molded article. Thereafter, the upper and lower ends of the molded body were cut by a thickness of 0.5 mm, respectively, to obtain an upper pad having a thickness of 2 mm.

Thereafter, the upper pad was subjected to surface milling and groove forming processes, and the upper pad was laminated with the lower pad using a hot melt adhesive.

Specific process conditions of the upper pad are summarized in the table below.

division Example 1 Example 2 Comparative Example 1 award
wealth
group
de Unreacted NCO group content of prepolymer 9.2% by weight 8.0 wt% 15% by weight casting mold single sheet single sheet single sheet Sheet machining (casting, cutting, grooving) sequential sequential sequential parts by weight of prepolymer 100 100 100 part by weight of surfactant 0.2~1.5 0.2~1.5 0.2~1.5 Parts by weight of solid foaming agent 0.5~1.0 0.5~1.0 0.5~1.0 Inert gas input (L/min) 0.5~1.5 0.5~1.5 0.5~1.5

test example

The urethane-based prepolymers or polishing pads obtained in Examples and Comparative Examples were tested for the following items, and the results are shown in Table 2.

(1) MALDI analysis of prepolymers

A prepolymer sample was dissolved in tetrahydrofuran (THF) and mixed with a matrix and a salt, and then using a matrix-assisted laser desorption/ionization (MALDI) measuring instrument (UltrafleXtreme®, Bruker) analyzed.

The results of Examples 1 and 2 are shown in FIGS. 1 and 2, and the results of Comparative Example 1 are shown in FIG. 3 . The molecular weight value of the peaks shown in FIG. 1 is the molecular weight to which Na ⁺ ions used as salts in MALDI analysis are bound.

As shown in FIG. 1 , in the MALDI data of Example 1, oligomers in which n is 0 to 3 in Formula 1 were observed (see the table below).

n value 0 One 2 3 Example 1 477.141 756.987 1037.236 1317.427

Also, as shown in FIG. 2 , oligomers having n of 0 to 6 in Formula 1 were observed in the MALDI data of Example 2 (see table below).

n value 0 One 2 3 4 5 6 Example 2 477.158 757.362 1037.539 1317.776 1598.983 1879.282 2159.376

Also, as shown in FIG. 3 , in the MALDI data of Comparative Example 1, oligomers in which n is 0 to 1 in Chemical Formula 1 were observed (refer to the table below).

n value 0 One Comparative Example 1 477.141 756.993

Other peaks in FIGS. 1 to 3 were confirmed to be a reaction product of TDI and PTMEG or a component added for MALDI analysis .

(2) NMR analysis of prepolymer

5 mg of the prepolymer sample _{was dissolved in CDCl 3} ^{and 1} H-NMR and ¹³ C-NMR analysis were performed at room temperature using a nuclear magnetic resonance (NMR) apparatus (JEOL 500 MHz, 90° pulse). The content of the reacted or unreacted aromatic diisocyanate monomer in the prepolymer was calculated by integrating the peaks of the reacted methyl group and unreacted methyl group of TDI in the obtained NMR data.

Specifically, when the weight of 2,4-TDI (hereinafter referred to as "4-reacted 2,4-TDI") in which only the NCO substituted at the 4-position among the two NCO groups is urethane-reacted with a polyol is 100 parts by weight , 2,4-TDI in which both NCO groups are urethane-reacted with polyol to form a chain (hereinafter referred to as "2,4-reacted 2,4-TDI"), 2 in which both NCO groups do not react with polyol ,6-TDI (hereinafter referred to as "unreacted 2,6-TDI") and 2,6-TDI (hereinafter referred to as "reacted 2,6-TDI") 2-reacted 2,6-TDI") was calculated by weight (otherwise, 2,4-TDI in which only NCO at the 2-position was reacted and 2,6-TDI in which both NCO groups were reacted were almost detected. did not).

The results are summarized in the table below.

division Example 1 Example 2 Comparative Example 1 content
(parts by weight) 4-reacted 2,4-TDI 100.00 100.00 100.00 2,4-reacted 2,4-TDI 36.63 49.65 13.90 unreacted 2,6-TDI 7.83 3.65 21.22 2-reacted 2,6-TDI 21.67 26.17 9.59 Total amount of TDI 166.13 179.47 144.71

division Example 1 Example 2 Comparative Example 1 content
(weight%)
(Full TDI
by weight) unreacted TDI 4.71 2.03 14.66 TDI with 2 NCOs (c1) 22.05 27.66 9.61 1 NCO reacted TDI (c2) 73.24 70.30 75.73 TDI with at least one NCO reacted 95.29 97.97 85.34 c1/c2 weight ratio 0.30 0.39 0.13

division Example 1 Example 2 Comparative Example 1 content (wt%)
(Urethane-based prepolymer
by weight) unreacted TDI (c3) 1.46 0.68 6.28 unreacted H12MDI (c4) 7.60 7.60 7.60 c3 + c4 9.06 8.28 13.88 c3 / c4 weight ratio 0.19 0.09 0.83

(3) hardness

The sample was cut to 5 cm Х 5 cm (thickness: 2 mm), and after storage at a temperature of 25° C. for 12 hours, Shore D hardness and Asker C hardness were measured using a durometer.

(4) specific gravity

The sample was cut to 2 cm Х 5 cm (thickness: 2 mm), and the multilayer specific gravity was measured using a hydrometer after storage at a temperature of 25° C. for 12 hours.

(5) Tensile strength

The sample was cut to 4 cm Х 1 cm (thickness: 2 mm), and the highest strength value just before the breaking of the polishing pad was measured at a speed of 50 mm/min using a universal tester (UTM).

(6) elongation

Cut the sample to 4 cm Х 1 cm (thickness: 2 mm), measure the maximum amount of deformation just before breakage of the polishing pad at a speed of 50 mm/min using a universal testing machine (UTM), and then measure the maximum amount of deformation compared to the initial length is expressed as a percentage (%).

(7) gel time

The prepolymer and the curing agent were mixed in an equivalent of 1:1 and stirred at 5,000 rpm, and the time it took for the mixture to gel at 70°C was measured.

The results are summarized in the table below.

division evaluation items Example 1 Example 2 Comparative Example 1 Top
pad thickness (mm) 2 2 2 Hardness (Shore D) 60 52 68 Specific gravity (g/cc) 0.8 0.8 0.8 Tensile strength (N/mm ² ) 21 18 25 Elongation (%) 125 200 63 gelation time (s) 108 121 50 bottom
pad type Non-woven Non-woven Non-woven thickness (mm) 1.1 1.1 1.1 Hardness (Asker C) 70 70 70 laminated
pad thickness (mm) 3.32 3.32 3.32 compressibility (%) 1.05 1.05 1.05

(8) Pore Characteristics

The pores of the polishing pad were observed with a scanning electron microscope (SEM) and shown in FIGS. 4A to 4C. As shown in FIGS. 4A to 4C , the pores of the polishing pads of Examples 1 and 2 were finely and uniformly distributed over a large area.

In addition, the characteristics of the pores were calculated based on the SEM image and summarized in the table below.

- Number average diameter: the average of the sum of the pore diameters on the SEM image divided by the number of pores

- Number of pores: the number of pores present per ^{0.3 cm 2 on the SEM image}

- Pore area ratio: Percentage of the area of the pores alone compared to the total area of the SEM image

division Example 1 Example 2 Comparative Example 1 Number average diameter (㎛) 22.454 23.313 20.523 Number of pores (per ^{0.3 cm 2)} 176 167 162 Pore area ratio (%) 38.165 38.896 38.245

(9) removal rate

The initial polishing rate immediately after the polishing pad was manufactured was measured as follows.

Silicon oxide was deposited on a silicon wafer having a diameter of 300 mm by a chemical vapor deposition (CVD) process. A polishing pad was attached to the CMP equipment, and the silicon oxide layer of the silicon wafer was installed to face the polishing surface of the polishing pad. While supplying the calcined ceria slurry on the polishing pad at a rate of 250 mL/min, the silicon oxide film was polished for 60 seconds under a load of 4.0 psi and a speed of 150 rpm. After polishing, the silicon wafer was removed from the carrier, mounted on a spin dryer, washed with distilled water, and dried with nitrogen for 15 seconds. For the dried silicon wafer, the film thickness change before and after polishing was measured using an optical interference type thickness measuring device (SI-F80R, Keyence). Then, the polishing rate was calculated using the following equation. The results are shown in FIG. 5 .

Polishing rate (Å/50 sec) = film thickness change before and after polishing (Å) / polishing time (50 sec)

As shown in FIG. 5 , the polishing pad of Examples 1 and 2 had an excellent initial polishing rate at an appropriate level, whereas the polishing pad of Comparative Example 1 had an excessively high initial polishing rate due to increased hard segment aggregation. Accordingly, the polishing pad of Comparative Example 1 is expected to have a sharp decrease in the polishing rate due to the pad glazing phenomenon.

(10) pad cut-rate

The polishing pad was pre-conditioned with deionized water for 10 minutes, and then conditioned while spraying deionized water for 1 hour. The cutting rate of the polishing pad was calculated by measuring the thickness changed during the conditioning process. The equipment used for conditioning was CTS's AP-300HM, the conditioning pressure was 6 lbf, the rotation speed was 100~110 rpm, and the disk used for conditioning was Sasol LPX-DS2. The results are shown in FIG. 6 .

As shown in FIG. 6 , the polishing pads of Examples 1 and 2 had excellent pad cutting rates during conditioning using a diamond disk, whereas the polishing pad of Comparative Example 1 had a low pad cutting rate due to increased hard segment aggregation.

Claims (9)

Including a urethane-based prepolymer, a curing agent and a foaming agent,
The urethane-based prepolymer is
a first oligomer in which n is 0 or 1 in Formula 1; and
and a second oligomer in which n is 2 or 3 in Formula 1,
The urethane-based prepolymer comprises 5% to 13% by weight of unreacted NCO groups based on the weight of the urethane-based prepolymer,
The composition, wherein the foaming agent is at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and an inert gas.
[Formula 1]

The method of claim 1,
The composition of the urethane-based prepolymer comprising the first oligomer and the second oligomer in a weight ratio of 1:0.2 to 1:5. The method of claim 1,
The urethane-based prepolymer further comprises a third oligomer in which n is an integer of 4 to 6 in Formula 1 above. 4. The method of claim 3,
The urethane-based prepolymer comprises the first oligomer, the second oligomer and the third oligomer in a weight ratio of 1:0.2:0.1 to 1:5:10. The method of claim 1,
The urethane-based prepolymer is
A composition further comprising a compound represented by the following formula (2):
[Formula 2]

In Formula 2, p is an integer of 5 to 30. The method of claim 1,
The urethane-based prepolymer, based on the weight of the urethane-based prepolymer, the composition comprising an unreacted aromatic diisocyanate monomer in an amount of 0.1 wt% to 5 wt%. The method of claim 1,
the composition has a gelation time of 80 seconds to 130 seconds,
A composition having, after curing, ^{a tensile strength of 10 N/mm 2} to 23 N/mm ² , an elongation of 80% to 250%, and a hardness of 40 Shore D to 65 Shore D. preparing a first oligomer in which n is 0 or 1 in Formula 1;
preparing a second oligomer in which n is 2 or 3 in Formula 1;
preparing a urethane-based prepolymer including the first oligomer and the second oligomer; and
Including; mixing the urethane-based prepolymer, a curing agent and a foaming agent;
The urethane-based prepolymer comprises 5% to 13% by weight of unreacted NCO groups based on the weight of the urethane-based prepolymer,
The method for producing a composition, wherein the foaming agent is at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and an inert gas.
[Formula 1]

A polyurethane resin and a plurality of fine pores dispersed in the polyurethane resin, wherein the polyurethane resin is derived from a composition comprising a urethane-based prepolymer, a curing agent and a foaming agent,
The urethane-based prepolymer is
a first oligomer in which n is 0 or 1 in Formula 1; and
and a second oligomer in which n is 2 or 3 in Formula 1,
The urethane-based prepolymer comprises 5% to 13% by weight of unreacted NCO groups based on the weight of the urethane-based prepolymer,
The polishing pad, wherein the foaming agent is at least one selected from a solid foaming agent having a hollow structure, a liquid foaming agent using a volatile liquid, and an inert gas.
[Formula 1]

Images