KR20190054600A - Polishing pad - Google Patents

Abstract

The present invention relates to a porous polyurethane polishing pad including a phase transition matter. According to the embodiment of the present invention, the porous polyurethane polishing pad is used for a chemical mechanical planarization (CMP) process of a semiconductor. The polishing pad includes a matrix resin, a blow hole, and a heat and impaction absorbing unit.

Description

Polishing pad {POLISHING PAD}

An embodiment relates to a polishing pad.

The CMP polishing pad is an essential material that plays an important role in the chemical mechanical planarization (CMP) process during the semiconductor manufacturing process, and plays an important role in implementing the CMP performance. Conventional CMP polishing pads were in the form of a polymer filled with microporous elements, typically a nonwoven felt coated with a polyurethane resin. The surface of the CMP polishing pad is composed of a groove responsible for the large flow of slurry and a pore supporting fine flow.

The pores in the polishing pad may be formed using a solid phase foaming agent having a void, a liquid phase foaming agent filled with a volatile liquid, a gas phase foaming agent such as an inert gas, a water-soluble substance, a fiber or the like, (See Korean Patent Publication No. 2006-0118010).

Korea Patent Publication No. 2006-0118010

Accordingly, it is an object of embodiments to provide a porous polyurethane polishing pad having improved surface hardness and thermostability.

In order to achieve the above object,

Matrix resin;

Pores disposed in the matrix resin; And

And a heat shock absorber disposed in the matrix resin.

The polishing pad according to the embodiment includes a thermal shock absorbing portion, which can suppress abrupt temperature rise and drop, and can have improved polishing performance.

1 is a cross-sectional view of a porous polyurethane polishing pad according to one embodiment.
2 is a sectional view of the heat shock absorbing particle.

One embodiment includes a matrix resin; Pores disposed in the matrix resin; And a heat shock absorber disposed in the matrix resin.

Referring to FIG. 1, a polishing pad according to one embodiment includes a matrix resin 300; Pores (200) disposed in the matrix resin; And a thermal shock absorber (100) disposed in the matrix resin.

Matrix resin

The matrix resin may be prepared from a composition comprising a urethane-based prepolymer and a curing agent. That is, the matrix resin may include a polyurethane resin. More specifically, the matrix resin may be formed by a curing reaction of a urethane-based prepolymer and a curing agent.

The term "prepolymer" generally means a polymer having a relatively low molecular weight in which a degree of polymerization is interrupted at an intermediate stage in order to easily form a final molded product. The prepolymer can be molded on its own or after reacting with other polymerizable compounds. Specifically, the urethane-based prepolymer may be one prepared by reacting an isocyanate compound with a polyol compound. More specifically, the urethane-based prepolymer may be one prepared by reacting a diisocyanate compound with a polyol compound.

Examples of the isocyanate compound used for preparing the urethane-based prepolymer include toluene diisocyanate (TDI), naphthalene-1,5-diisocyanate, paraphenylene diisocyanate p-phenylene diisocyanate, tolidine diisocyanate, 4,4'-diphenyl methane diisocyanate, hexamethylene diisocyanate (HDI), dicyclohexyl But are not limited to, dicyclohexylmethane diisocyanate, methylene diphenyl diisocyanate (MDI), 1-isocyanato-4 - [(4-isocyanatocyclohexyl) methyl] cyclohexane, At least one member selected from the group consisting of 4 - [(4-isocyanatocyclohexyl) methyl] cyclohexane, H12MDI) and isophorone diisocyanate Asia may be Nate.

The polyol compound that can be used in the production of the urethane-based prepolymer includes, for example, a polyether polyol, a polyester polyol, a polycarbonate polyol, a polycaprolactone polyol polyol, and an acryl polyol. The polyol may have a weight average molecular weight (Mw) of 300 to 3,000 g / mol.

The urethane-based prepolymer may have a weight average molecular weight of 500 to 3,000 g / mol. Specifically, the urethane-based prepolymer may have a weight average molecular weight (Mw) of 600 to 2,000 g / mol, or 800 to 1,000 g / mol.

The urethane-based prepolymer may contain 8 to 12% by weight of an isocyanate terminal group.

As an example, the urethane-based prepolymer may be a polymer having a weight average molecular weight (Mw) of 500 to 3,000 g / mol, which is obtained by using toluene diisocyanate as an isocyanate compound and polytetramethylene ether glycol as a polyol.

The curing agent may be at least one selected from the group consisting of an amine compound and an alcohol compound. Specifically, the curing agent may be at least one compound selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols. More specifically, the curing agent is selected from the group consisting of 4,4'-methylenebis (2-cloroaniline), diethyltoluenediamine, diaminodiphenyl methane Diaminodiphenyl sulphone, m-xylylene diamine, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenediamine, and the like. Diethyleneglycol, dipropyleneglycol, butanediol, butanediol, and the like may be used. [0033] The term " polyisocyanate " Hexanediol, glycerine, trimethylolpropane, and bis (4-amino-3-chlorophenyl) methane. It may be at least one member selected from the group eojineun.

pore

The pores are disposed in the matrix resin. Specifically, the pores may be formed by a foaming agent. More specifically, pores in the polishing pad are dispersed in the matrix resin, and the pores may be derived from thermally expanded microcapsules as a solid-phase blowing agent, or formed from a gas-phase blowing agent.

The foaming agent may be at least one selected from the group consisting of a gas phase foaming agent, a volatile liquid phase foaming agent and a solid phase foaming agent.

The solid-state blowing agent may be a thermally expanded microcapsule whose size is controlled (hereinafter referred to as 'thermally expanded microcapsule'). The thermally expanded microcapsules may be obtained by heating and expanding the thermally expandable microcapsules. The thermally expanded microcapsules have a uniform particle size as a structure of an already-expanded microballoons, and thus the particle size of pores can be uniformly controlled. Specifically, the solid-state blowing agent may be a microballoon structure having an average particle diameter of 5 to 200 mu m.

The gas-phase foaming agent is not particularly limited as long as it is an inert gas that does not participate in the reaction between the urethane-based prepolymer and the curing agent. Specifically, the gas phase foaming agent 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). More specifically, the gas phase blowing agent may be nitrogen gas (N ₂ ) or carbon dioxide gas (CO ₂ ).

The gas-phase foaming agent may be added in a volume corresponding to 10 to 30% of the total volume of the polyurethane composition (including urethane-based prepolymer, curing agent and foaming agent). Specifically, the gas phase blowing agent may be added in a volume corresponding to 15 to 30% of the total volume of the polyurethane composition.

The pores may be included in an amount of 40 to 60% by volume based on the total volume of the polishing pad. More specifically, the pores may be comprised between 45 and 55 vol% based on the total volume of the polishing pad.

The average diameter of the pores may be 10 to 100 [mu] m.

Heat shock Absorbing portion

The heat shock absorber is disposed in the matrix. In addition, the heat shock absorber may include a phase change material.

The phase change material may be disposed in the matrix resin in the form of a plurality of particles. That is, the heat shock absorbing part may be a plurality of heat shock absorbing particles.

The particles (heat shock-absorbing particles) may have an average diameter of 5 mu m or less. Specifically, the particles may have an average diameter of 1 탆 to 5 탆.

The heat shock absorber may include a core including the phase change material; And a shell surrounding the core.

As shown in FIG. 2, the thermal shock absorber 100 includes a core 110 including the phase change material; And a shell 120 surrounding the core. That is, the heat shock absorbing particles may be in the form of a core-shell.

The shell may comprise melamine or acetonitrile.

The phase change material (PCM) is capable of absorbing or releasing a large amount of heat as the phase changes from solid to liquid, from liquid to gas, or vice versa, with little change in temperature at a specific temperature Means a latent heat material, a heat storage material, or a material having a heat control function, which is a temperature control material that stores ambient heat and releases it when necessary. Unlike conventional regenerators, when the phase transition material reaches the phase change temperature (melting point of PCM), it absorbs a large amount of heat, but the temperature remains constant. When the ambient temperature falls, the phase transition material releases a latent heat that is stored as the phase transition material solidifies. Thus, the phase transition material absorbs heat and releases heat to maintain ambient temperature. In addition, phase change materials store 5 to 14 times more heat per volume unit than known heat storage materials such as water, stone, and stone. As a result, the porous polyurethane polishing pad of the embodiment including the phase transition material exhibits better thermostability than the polishing pad not containing the phase transition material.

The phase transition material may have a melting point of 30 to 60 캜. Specifically, the phase transition material may have a melting point of 35 ° C to 57 ° C. Therefore, the thermal shock absorber effectively absorbs the thermal shock in the above-mentioned temperature range, and can prevent the sudden rise or fall of the temperature.

The phase change material may be selected from the group consisting of hydrated inorganic salts, polyhydric alcohols, polyethylene glycol (PEG), polytetrahydrofuran (PTMG), polyethylene glycol (PEG) and polyethylene terephthalate Linear hydrocarbons having 10 to 40 carbon atoms, and the like.

The hydrated inorganic salt is _{LiNO 3 · 3H 2 O, Cabr} 2 · 6H 2 O, Na 2 SO 4 · 10H 2 O, NaNH 4 SO 4 · 2H 2 O, Na 2 SiO 3 · 5H 2 O, Na 3 PO 4 12H ₂ O, Na (CH ₃ COO) 3H ₂ O, NaHPO ₄ .12H ₂ O, K ₂ HPO ₄ .3H ₂ O, K ₂ HPO ₄ .3H ₂ O, K ₃ PO ₄ .7H ₂ O, _{Fe (NO 3) 3 · 9H} 2 O, FeCl 3 · 2H 2 O, Fe 2 O 3 · 4SO 4 · 9H 2 O, Ca (NO 3) 2 .3H 2 O and CaCl ₂ · 6H ₂ O the group consisting of And the like.

The polyhydric alcohol means an alkyl group containing at least two alcohol groups, and specifically includes at least one selected from the group consisting of 2,2-dimethylpropane-1,3-diol and hexamethylpropane-1,3- .

The copolymer of polyethylene glycol (PEG), polytetrahydrofuran (PTMG) and polyethylene glycol (PEG) and polyethylene terephthalate (PET) may have a weight average molecular weight of 500 to 20,000 g / mol, respectively.

The linear hydrocarbons are linear hydrocarbons having 10 to 40 carbon atoms, and specifically may be linear hydrocarbons having 10 to 35 carbon atoms.

The heat shock absorber may be included in an amount of 1 to 20% by volume based on the total volume of the polishing pad. Specifically, the heat shock absorber may be contained in an amount of 1 to 10% by volume based on the total volume of the polishing pad.

The ratio of the total volume of the heat shock absorber to the total volume of the pores may be from 1: 2 to 1:60. Specifically, the ratio of the total volume of the heat shock absorber to the total volume of the pores may be from 1: 3 to 1:55.

The porous polyurethane polishing pad may have a surface hardness of 40 to 70 shore D at 25 占 폚. Specifically, the porous polyurethane polishing pad may have a surface hardness of 50 to 70 Shore D, or 50 to 68 Shore D at 25 占 폚.

The porous polyurethane polishing pad has a thickness of 1.5 to 2.5 mm. Specifically, the porous polyurethane polishing pad may have a thickness of 1.8 to 2.5 mm. When the thickness of the polishing pad is within the above range, the basic physical properties as a polishing pad can be sufficiently exhibited.

The porous polyurethane polishing pad may have grooves on the surface for mechanical polishing. The grooves may have appropriate depth, width and spacing for mechanical polishing and are not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[ Example ]

Example  1. Porous polyurethane Of the polishing pad  Produce

1-1: Urethane Prepolymer  Produce

50 parts by weight of polytetramethylene ether glycol (weight average molecular weight: 1,000 g / mol) as a polyol compound to 100 parts by weight of toluene diisocyanate (TDI) as an isocyanate compound were put into a four-necked flask, To prepare a urethane-based prepolymer (weight average molecular weight: 1,000 g / mol) having an unreacted NCO content of 9.1% by weight.

1-2: Configuration of the device

In a casting machine equipped with a urethane-based prepolymer, a curing agent and an inert gas injection line, the prepolymer tank was filled with the urethane prepolymer of Example 1-1, the hardener tank was filled with triethylenediamine (manufactured by Dow Co.) (N ₂ ) were prepared. 1.5 parts by weight of a solid phase blowing agent (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., product name: F-65DE, average particle diameter: 50 占 퐉) and 10 parts by weight of a phase transition material were mixed with 100 parts by weight of the urethane-based prepolymer. , C ₂₂ H ₄₈ , Tm: 44 ° C, latent heat: 37.5 cal / g, core-shell type, average diameter: 1 μm) were preliminarily mixed and injected into the prepolymer tank.

1-3: Preparation of Porous Polyurethane

Example 1-2 A urethane type prepolymer, a curing agent and an inert gas were stirred into a mixing head at a constant speed through respective input lines. At this time, the molar equivalent of the NCO group of the urethane prepolymer and the molar equivalent of the reactive group of the curing agent were adjusted to 1: 1, and the total charge was maintained at a rate of 10 kg / min. In addition, the inert gas was adjusted so that the density of the porous polyurethane was constantly 0.8 kg / m ² , and the curing agent was added in an amount of 30 parts by weight based on 100 parts by weight of the urethane-based prepolymer. The injected raw materials were mixed with stirring and then injected into a mold (1,000 mm in width, 1,000 mm in height, 3 mm in height) and solidified to obtain a sheet-like porous polyurethane.

The surface of the prepared porous polyurethane was ground using a grinder and grooved using a tip to make an average thickness of 2 mm.

Example  2 and 3, and Comparative Example  One.

A porous polyurethane polishing pad having an average thickness of 2 mm was prepared in the same manner as in Example 1, except that the kind and content of the phase change material were changed as shown in Table 1 below.

Phase transition material Kinds content Example 1 n-docosane (C ₂₂ H ₄₈ , Tm: 44 캜, latent heat: 37.5 cal / g) 10 parts by weight Example 2 n-tetracosane (C ₂₄ H ₅₀ , Tm: 50.6 ° C, latent heat: 38.7 cal / g) 20 parts by weight Example 3 n-hexadosane (C ₂₆ H ₅₄ , Tm: 56.3 캜, latent heat: 38.6 cal / g) 30 parts by weight Comparative Example 1 - -

Test Example .

The properties of the polishing pads prepared in the above Examples and Comparative Examples were measured according to the following conditions and procedures and are shown in Table 2 below.

(1) Surface hardness

shore D hardness was measured. The polishing pad was cut into a size of 2 cm × 2 cm (thickness: about 2 mm), and then cut at a temperature of 25 ° C., 30 ° C., 50 ° C. and 70 ° C. and a humidity of 50 ± 5% Time. Then, the hardness of the polishing pad was measured using a hardness meter (D-type hardness meter).

(2) average particle diameter

The polishing pad was cut into squares of 2 cm x 2 cm (thickness: 2 mm) and observed with a scanning electron microscope (SEM) at a magnification of 100 times. The particle diameters of the whole pores and the thermal shock absorbers were measured from the images obtained by using the image analysis software, and the average particle diameters of the pores and the heat shock absorbers were calculated.

(3) Thermostability measurement

Using a CMP polishing equipment, a silicon wafer having a diameter of 300 mm on which silicon oxide was deposited by a CVD process was installed. The silicon oxide layer (silicon oxide film) of the silicon wafer was set down on a platen to which the multilayer polishing pad was attached. Thereafter, the polishing load was adjusted to 4.0 psi and the silicon oxide film was polished by rotating the platen at 150 rpm for 50 seconds while introducing the calcined ceria slurry onto the polishing pad at a rate of 250 ml / min. The maximum temperature of the polishing pad during the polishing process and the temperature of the polishing pad after 30 seconds of standing at room temperature after the polishing process were measured.

Example 1 Example 2 Example 3 Comparative Example 1 25 ° C Surface hardness (Shore D) 65.1 62.0 59.3 72.0 30 ° C Surface hardness (Shore D) 67.0 64.0 60.1 70.0 40 ° C Surface hardness (Shore D) 65.0 63.5 58.2 68.9 50 ° C Surface hardness (Shore D) 60.2 57.0 56.6 67.0 70 ° C Surface hardness (Shore D) 58.0 54.8 52.2 63.6 The average diameter (占 퐉) of the pore and the heat shock- 35.3 32.7 28.9 38.1 Constant temperature Maximum temperature (℃) 64.3 62.5 60.7 65.2 Temperature after leaving (℃) 50.1 55.6 58.1 40.3

As shown in Table 2, in Examples 1 to 3 including the phase transition material, the average diameter of the pores and the thermal shock absorbers decreased in proportion to the content of the phase transition material, the maximum temperature during polishing was lower, and the rate of temperature change after standing was small All.

100: Heat shock absorber 200: Groundwork

Claims (12)

Matrix resin;
Pores disposed in the matrix resin; And
And a heat shock absorber disposed in the matrix resin.
The method according to claim 1,
The matrix resin is prepared from a composition comprising a urethane-based prepolymer and a curing agent,
Wherein the pores have an average diameter of 10 mu m to 100 mu m.
The method according to claim 1,
Wherein the thermal shock absorbing portion comprises a phase transition material.
The method of claim 3,
A core including the phase change material; And a shell surrounding the core.
5. The method of claim 4,
Wherein the shell comprises melamine or acetonitrile.
The method of claim 3,
Wherein the phase transfer material is selected from the group consisting of inorganic hydrated salts, polyhydric alcohols, polyethylene glycol (PEG), polytetrahydrofuran (PTMG), copolymers of polyethylene glycol (PEG) and polyethylene terephthalate (PET), and linear hydrocarbons of 10 to 40 carbon atoms Wherein the polishing pad comprises at least one selected from the group consisting of:
The method according to claim 6,
Wherein the hydrated inorganic salt _{LiNO 3 · 3H 2 O, Cabr} 2 · 6H 2 O, Na 2 SO 4 · 10H 2 O, NaNH 4 SO 4 · 2H 2 O, Na 2 SiO 3 · 5H 2 O, Na 3 PO 4 12H ₂ O, Na (CH ₃ COO) 3H ₂ O, NaHPO ₄ .12H ₂ O, K ₂ HPO ₄ .3H ₂ O, K ₂ HPO ₄ .3H ₂ O, K ₃ PO ₄ .7H ₂ O, _{Fe (NO 3) 3 · 9H} 2 O, FeCl 3 · 2H 2 O, Fe 2 O 3 · 4SO 4 · 9H 2 O, Ca (NO 3) 2 .3H 2 O and CaCl ₂ · 6H ₂ O the group consisting of Wherein the polishing pad comprises at least one selected from the group consisting of:
The method according to claim 6,
Wherein the polyhydric alcohol comprises at least one member selected from the group consisting of 2,2-dimethylpropane-1,3-diol and hexamethylpropane-1,3-diol.
The method according to claim 6,
Wherein the copolymer of polyethylene glycol (PEG), polytetrahydrofuran (PTMG) and polyethylene glycol (PEG) and polyethylene terephthalate (PET) has a weight average molecular weight of 500 to 20,000 g / mol, respectively.
The method of claim 3,
Wherein the phase transition material has a melting point of from 30 캜 to 60 캜.
The method according to claim 1,
Wherein the thermal shock absorber is comprised between 1 and 20 vol% based on the total volume of the polishing pad.
The method according to claim 1,
Absorbing portion is disposed in the matrix resin in the form of a plurality of particles,
Wherein the particles have an average diameter of 1 占 퐉 to 5 占 퐉.

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