KR101234313B1 - Method for manufacturing porous sheet and porous sheet manufactured by the method - Google Patents

Abstract

The present invention comprises the steps of: a) preparing a polymer resin sheet comprising a supercritical extract object soluble in a supercritical fluid; And b) injecting a supercritical fluid into the polymer resin sheet to extract the supercritical extract object included in the polymer resin sheet to form pores in the polymer resin sheet. It provides a prepared porous sheet.

Description

Manufacturing method of porous sheet and porous sheet manufactured by the same {METHOD FOR MANUFACTURING POROUS SHEET AND POROUS SHEET MANUFACTURED BY THE METHOD}

The present invention relates to a method for producing a porous sheet using supercritical fluid extraction (SFE) and a porous sheet produced thereby.

This application claims the benefit of the application date of Korean Patent Application No. 10-2009-0051598 filed to the Korea Intellectual Property Office on June 10, 2009, the entire contents of which are incorporated herein.

Chemical mechanical polishing (CMP) processes are used to form flat surfaces on semiconductor wafers, field emission displays and many other microelectronic substrates in the manufacture of microelectronic devices. For example, manufacturing processes for semiconductor devices generally include the formation of various processing layers, selective removal or patterning of some of these layers, and the formation of semiconductor wafers by deposition of additional processing layers on the surface of the semiconductor substrate. For example, the processing layer may include an insulating layer, a gate oxide layer, a conductive layer, a metal or glass layer, and the like. In general, it is desirable that at certain stages of the wafer process the top surface of the processing layer is planar, ie flat, for the deposition of subsequent layers.

Chemical mechanical polishing (CMP) processes are used to prepare wafers for subsequent processing steps by polishing and removing some of the deposited material such as conductive or insulating materials from the wafer.

In a typical chemical mechanical polishing (CMP) process, the wafer is mounted face down on a carrier included in a chemical mechanical polishing (CMP) tool. Force is applied to the carrier and wafer downwards towards the polishing pad. The carrier and wafer rotate on a rotating polishing pad on a polishing table of a chemical mechanical polishing (CMP) tool. Generally, polishing compositions (also called polishing slurries) are incorporated between the rotating wafer and the rotating polishing pad during the polishing process. Typically, the polishing composition contains a chemical that interacts with or dissolves a portion of the top wafer layer, and an abrasive that physically removes a portion of the layer. The wafer and the polishing pad can rotate in the same direction or in opposite directions, which is preferred for carrying out a particular polishing process in either direction. The carrier may also reciprocate in a polishing pad on a polishing table.

Polishing pads used in such chemical mechanical polishing (CMP) processes include soft and hard pad materials (polymer-impregnated fabrics, microporous films, cellular polymeric foams, non-porous). porous) polymer sheets and sintered thermoplastic particles).

Pads containing a polyurethane resin impregnated with a polyester nonwoven are examples of polymer-impregnated woven polishing pads. The microporous polishing pad includes a microporous urethane film coated on the base material. These polishing pads are closed-cell porous films. Foamable polymeric foam polishing pads contain a closed-cell structure that is randomly and uniformly distributed three-dimensionally.

Most of the recent polishing pads use a porous sheet having closed-pore in the pad, where the pores are used to improve the efficiency of the process by controlling the flow of the polishing slurry. Therefore, when forming pores in the polishing pad, it is important to uniformly and evenly dispersed.

As an example of manufacturing such a polishing pad, Korean Patent No. 10-0191227 describes a method of manufacturing a pad by adding a hollow polymeric microelement to a polymeric matrix.

However, the hollow polymeric microelement has a shell having a thickness of several microns, and this shell has a problem in that a scratch can be formed on a polishing object such as a wafer in a chemical mechanical polishing (CMP) process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preparing a porous sheet and a porous sheet manufactured thereby, which are excellent in uniformity and dispersibility of pores, can reduce scratch formation on a process, and can improve process efficiency. will be.

The present invention comprises the steps of: a) preparing a polymer resin sheet comprising a supercritical extract object soluble in a supercritical fluid; And b) injecting a supercritical fluid into the polymer resin sheet to extract the supercritical extract object included in the polymer resin sheet to form pores in the polymer resin sheet. .

It provides a porous sheet produced by the manufacturing method according to the present invention.

Provided are a polishing pad comprising a porous sheet according to the present invention.

According to the present invention, it is possible to provide a method for producing a porous sheet capable of forming pores with excellent uniformity and dispersibility in the sheet. In addition, since it is a method of extracting a substance that is soluble in the supercritical fluid, it is possible to form pores without leaving a residue inside the sheet. As a result, the occurrence of scratches on the wafer, which is the polishing target, may be reduced by the residue, and process efficiency may be improved.

1 is a view showing a method for manufacturing a porous sheet according to the present invention.
2 is a SEM photograph of the porous sheet according to Example 1 of the present invention.
3 is a graph showing the experimental results of Examples 1 and 3 to 5.
4 is an SEM photograph of a sheet according to a comparative example.

Method for producing a porous sheet according to the present invention comprises the steps of: a) preparing a polymer resin sheet comprising a supercritical extract object soluble in a supercritical fluid; And b) injecting a supercritical fluid into the polymer resin sheet to extract the supercritical extract contained in the polymer resin sheet to form pores in the polymer resin sheet.

As the supercritical extract object of step a), a material selected from an aromatic compound, an aliphatic hydrocarbon, and an aliphatic alcohol may be used.

Here, examples of the aromatic compound include naphthalene, anthracene, chrysene and pentacene. As the aliphatic hydrocarbon, C ₇ to C ₁₀ aliphatic hydrocarbon may be used, but is not limited thereto. Specifically, mineral oil, octane, decane and dodecane may be used as examples. Can be. Examples of the aliphatic alcohols include heptanol, nonanol, and dodecanol.

Among them, naphthalene or octane may be used as the supercritical extract, but is not limited thereto.

The shape of the supercritical extract object included in the polymer resin sheet may be spherical or elliptical, but is not limited thereto.

The content of the supercritical extractable object in the polymer resin sheet of step a) may be 5 to 50% by weight, more preferably 20 to 40% by weight.

The polymer resin sheet of step a) is polyurethane, thermoplastic elastomer, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastomeric rubber, styrene copolymer, polyaromatic, fluoropolymer, polyimide, crosslinked polyurethane Crosslinked polyolefins, polyethers, polyesters, polyacrylates, elastomeric polyethylenes, polytetrafluoroethylenes, polyethyleneterraphthalates, polyarylenes, polystyrenes, polymethylmethacrylates, copolymers and block copolymers thereof, And it may include a polymer resin selected from the group consisting of mixtures and blends thereof. Here, polyurethane is a material having excellent abrasion resistance, and may be most preferable as a material of the polishing pad. In addition, it is also possible to obtain a polymer having desired physical properties by changing the raw material composition in various ways, which is a great feature of polyurethane, and is suitable for forming a polishing pad.

The step a) comprises: a1) mixing the supercritical extract and a prepolymer of a polymer resin; And a2) curing the mixture mixed in the step a1).

In step a1), the mixing conditions of the supercritical extract and the prepolymer of the polymer resin may vary depending on the mixing speed of the impeller and the temperature of the reactor. It may also be used simultaneously with the curing agent when mixing. Here, the mixing speed of the impeller and the temperature conditions of the reactor can be variously adjusted, preferably the mixing speed of the impeller may be 200 to 3000rpm, the temperature of the reactor may be 40 to 70 ℃.

In step a1), 1,4-butanediol (1,4-butandiol), 4,4'-methylenebis (2-chloroaniline) (4,4'-methylenebis (2-chloroaniline)), ethylene glycol, 1 , 2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2 At least one selected from the group consisting of 4-trimethylpetanediol, hydroquinone, bis (2-hydroxyethyl) hydroquinone, 4,4'-dihydroxybiphenyl, bisphenol A, bisphenol F, and mixtures thereof Further chain extenders can be added.

In the step a2), it can be cured for 4 to 48 hours at 70 to 100 ℃.

When the sheet is manufactured using the polyurethane resin in step a), the polyurethane may be formed by an organic polyisocyanate, a polyurethane prepolymer, a polyol compound, and a chain extender.

Here, it may include 1 to 20% by weight of organic polyisocyanate, 10 to 88% by weight of polyurethane prepolymer, 10 to 88% by weight of polyol compound, and 1 to 50% by weight of chain extender.

Examples of the organic polyisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4, Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, ethylene Aliphatic diisocyanates such as diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexyl methane diisocyanate And alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated m-xylylene diisocyanate, norbornane diisocyanate, and the like. have. It can be used 1 type or in mixture of 2 or more types. However, this is not a kind limited.

As said organic polyisocyanate, in addition to the said diisocyanate compound, a trifunctional or more than trifunctional polyisocyanate compound can also be used. As a polyfunctional isocyanate compound, a series of diisocyanate adduct compounds can be used as desmodule-N (Bayer Corporation) or brand name duranate (made by Asahi Kasei Co., Ltd.).

Examples of the polyol compound include high molecular weight polyols such as polyether polyols, polyester polyols, polycarbonate polyols, and acrylic polyols. In addition to the above high molecular weight polyols, low molecular weight polyols may be used together. These polyol compounds can be used 1 type or in mixture of 2 or more types. However, this is not a kind limited.

The ratio of the above-mentioned organic polyisocyanate, polyol compound and chain extender can be varied in various ways depending on the molecular weight and the desired physical properties of the use (for example, a polishing pad) of the polyurethane produced therefrom. In order to obtain a polishing pad having desired polishing properties, the number of isocyanate groups of the organic polyisocyanate relative to the total number of functional groups (total of active hydrogen groups such as hydroxyl groups and amino groups) of the polyol compound and the chain extender is in the range of 0.95 to 1.15. Preferably, it may be more preferably 0.99 to 1.10. In addition, the ratio of a high molecular weight component and a low molecular weight component in a polyol compound can be determined by the characteristic calculated | required by the polyurethane manufactured from these.

In the step a), when the sheet is manufactured using a polyurethane resin, the polyurethane to be a matrix can be manufactured by applying a urethanization technique such as a melting method and a solution method, but in consideration of cost, working environment, etc. It is preferable to manufacture by the melting method.

Polyurethane can be produced either by a prepolymer method or a one-shot method, but a prepolymer method in which an isocyanate terminated prepolymer is synthesized from an organic polyisocyanate and a polyol compound in advance and a chain extender is reacted therewith is produced. It is suitable because of excellent physical properties of urethane.

On the other hand, what is marketed as an isocyanate terminal prepolymer made from an organic polyisocyanate and a polyol compound can be applied to the production method of polyurethane by the prepolymer method as long as it is suitable for the present invention. Isocyanate-terminated prepolymer may have a molecular weight of about 800 to 5000 excellent in processability, physical properties and the like, may be suitable.

In the prepolymer method, the isocyanate terminal prepolymer is an isocyanate group-containing compound, and the chain extender (polyol compound, if necessary) is an active hydrogen group-containing compound. In the one-shot method, the organic polyisocyanate is an isocyanate group-containing compound, and the chain extender and the polyol compound are active hydrogen group-containing compounds.

In the production of such polyurethanes, stabilizers such as antioxidants, surfactants, lubricants, pigments, fillers, antistatic agents, and other additives may be further added to the polyurethane stock solution as necessary.

In step b), as a method of injecting the supercritical fluid into the polymer resin sheet prepared in step a), a pressurized gas injection process of forcibly injecting the supercritical fluid into the polymer resin sheet using high pressure may be used. have.

The supercritical fluid injected into the polymer resin sheet in step b) will be described in detail.

Here, a supercritical fluid is a state in which a substance that becomes a gas and a liquid at a normal temperature and pressure also cannot be distinguished from a gas and a liquid because an evaporation process does not occur when a certain high temperature and high pressure limit called a supercritical point is exceeded. That is, the critical state, which means the material in this state.

Supercritical fluids are produced by applying sufficient elevated temperature and pressure to the gas to create a supercritical state in which the gas behaves like a fluid.

The gas may be a hydrocarbon, chlorofluorocarbons, hydrochlorofluorocarbons (eg Freon), nitrogen, carbon dioxide, carbon monoxide or combinations thereof.

The gas is preferably a nonflammable gas, for example a gas containing no C-H bond. More preferably, the gas is nitrogen, carbon dioxide, or a combination thereof. Most preferably, the gas is carbon dioxide or a gas containing carbon dioxide.

The gas is preferably converted to supercritical gas before being injected into the polymer resin sheet.

If the gas is carbon dioxide, the temperature is at least 31 ° C. and the pressure is between 7 MPa (about 1000 psi) and 35 MPa (about 5000 psi) (eg, 19 MPa (about 2800 psi) to 26 MPa (about 3800 psi)).

The supercritical fluid of step b) may preferably include one or more selected from supercritical carbon dioxide, supercritical isobutane, supercritical butane, supercritical propane, supercritical pentane, and supercritical nitrogen.

The step b) may be performed at a pressure of 50 to 300 atm and a temperature of 25 to 120 ° C., preferably at a pressure of 70 to 200 atm and a temperature of 30 to 80 ° C. Step b) may be performed in a supercritical equipment known in the art.

In step b), it may be mixed with acetone, alcohol and the like to perform a supercritical fluid extraction.

Here, in the mixing method, the supercritical fluid may be injected at the same time, or the solvent may be mixed in the supercritical reactor in advance. The solvent may vary depending on the supercritical extract included in the polymer resin sheet, and for example, acetone, alcohol, hexane, and the like may dissolve the supercritical extract.

As such, when the supercritical fluid of step b) is injected into the polymer resin sheet prepared in step a), the supercritical fluid dissolves the supercritical extract contained in the sheet, thereby preparing in step a). The pores can be formed without leaving a residue in the polymer resin sheet. Herein, the pores formed may be closed pores. Here, the closed pore means a pore in which pores are not independently connected to other pores.

The pores formed in the polymer resin sheet in step b) may be spherical or elliptical, but are not limited thereto.

In step b), the average diameter of the pores formed in the polymer resin sheet may be 80 micrometers or less, preferably 5 to 50 micrometers, and more preferably 10 to 30 micrometers. Here, the average diameter of the pores means the average value of the lines when a plurality of lines passing through the center of the circle around the circle.

In step b), the density of the sheet having pores formed in the polymer resin sheet may be 0.5 to 1 g / cm 3, preferably 0.6 to 1 g / cm 3, and more preferably 0.7 to 0.9 g / cm 3. have.

The polymer resin sheet in which the pores are formed in step b) may have a porosity of 50% or less, preferably 10 to 50%, and more preferably 20 to 40%.

As described above, according to the present invention, pores can be formed without leaving a residue in the polymer resin sheet (see FIG. 2). However, in the case of the conventional pressurized gas foaming method, when foamed by injection into a polyurethane that is cured, that is, crosslinking is advanced, there is a disadvantage that foaming is not performed depending on the degree of curing. In the case of the non-crosslinking or low modulus polyurethane, foaming proceeds by injection of pressurized gas, but it is difficult to show the physical properties of the pad for use in a CMP pad. When foaming using a pressurized gas method to a polyurethane having a high degree of curing, foaming does not occur at all or a polymer matrix is broken (see FIG. 4).

On the other hand, the present invention provides a porous sheet produced by the above-described manufacturing method.

The porous sheet according to the present invention can be used as a polishing pad. The porous sheet alone may be used as a polishing pad, or a plurality of porous sheets may be laminated and used as a polishing pad. In addition, by attaching another film to the porous sheet may be used as a polishing pad.

Hereinafter, the present invention will be described in detail with reference to FIG. 1.

As an example, as shown in FIG. 1, a prepolymer of polyurethane is mixed with aliphatic hydrocarbons, naphthalene or fish oil as a solute soluble in a supercritical fluid and dispersed well. This prepolymer mixture is reacted with 1.4-butanediol or 4,4'-methylenebis (2-chloroaniline) (4,4'-methylenebis (2-chloroaniline)) as a chain extender. Form a chain. It is cured for 4-6 hours in an oven at 100 ℃ to form the desired shape in a mold. The cured polyurethane is placed in a supercritical equipment to extract the solute. Here, CO ₂ may be used as the supercritical fluid, and supercritical extraction may be performed by mixing with acetone or alcohol. Specifically, acetone or an alcohol, such as alcohol, is simultaneously put into the polyurethane sheet to be extracted. In other words, put acetone or alcohol in the supercritical extraction equipment, close the supercritical extraction equipment and inject CO ₂ to the desired pressure. Alternatively, CO ₂ can be injected simultaneously into the supercritical equipment.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example  One

In Example 1, a mixed solution is first prepared by mixing a prepolymer and octane. The prepolymer uses L325 (Chemtura, 9.17% NCO), and octane is used as the supercritical extract that is dissolved in the supercritical fluid, that is, the pore forming body.

First, 1000 g of prepolymer and 400 g of octane were put into a 50 ° C reactor and mixed for 5 minutes. The octane is then dispersed into the prepolymer to form spherical droplets in the prepolymer. Thereafter, 260 g of MOCA (methylenebis (2-chloroaniline)) was added and mixed together. The prepared polyurethane mixture was poured into a mold and gelled at room temperature for 1 hour and then cured in an oven at 100 ° C. for 24 hours.

The cured polyurethane mixture was cut thin to 3 mm thick and placed in a supercritical extractor. The temperature of the supercritical extractor was 45 ° C. and carbon dioxide was pressurized into the apparatus to maintain the pressure at 150 bar. The pressure was released after holding in the apparatus for 1 hour. Polyurethane samples were removed from the apparatus, kept at room temperature for 1 hour, and then maintained at 100 ° C. for 1 hour.

The sample thus prepared had a density of 0.802 g / cm ³ and a hardness of 50 with a Shore D meter. SEM pictures of the samples are shown in FIG. 2. The storage modulus and tan delta of this sample are shown in FIG. 3.

As described above, when the porous sheet is manufactured by using supercritical fluid extraction (SFE) according to the present invention, since the melting material is extracted in the supercritical fluid, pores are formed without leaving residue inside the sheet. Can be formed. This can reduce the formation of scratches on the polishing object by the residue of the sheet during the polishing process, it is possible to improve the process efficiency.

Example  2

In Example 2, prepolymer and MOCA are mixed first, followed by octane.

First, the prepolymer was put into the reactor 1000g L325 (NCO% 9.17%, manufactured by Chemtura) and maintained at a temperature of 50 ℃. 260 g of pre-melted MOCA was added and mixed at 1000 rpm for 30 seconds, followed by mixing 400 g of octane.

The prepared polyurethane mixture was poured into a mold and gelled at room temperature for 30 minutes and then cured in an oven at 100 ° C. for 16 hours.

The cured polyurethane mixture was cut thin to 3 mm thick and placed in a supercritical extractor. The temperature of the supercritical extractor was pressurized to 40 bar with carbon dioxide at 40 ° C. to maintain the pressure at 100 bar. The pressure was released after holding in the apparatus for 2 hours. Polyurethane samples were removed from the apparatus, kept at room temperature for 1 hour, and then maintained at 100 ° C. for 1 hour.

Example  3

In Example 3, H ₁₂ MDI is added to produce a high modulus pad.

The same procedure as in Example 1 was conducted except that H ₁₂ MDI was added to L325 to prepare a prepolymer having an NCO% of 9.7%. The storage modulus and tan delta of the pads prepared in Example 3 are shown in FIG. 3.

Example  4

In Example 4, H ₁₂ MDI is added to produce a high modulus pad.

The same procedure as in Example 1 was carried out except that H ₁₂ MDI was added to L325 to prepare a prepolymer having an NCO% of 11%. The storage modulus and tan delta of the pads prepared in Example 4 are shown in FIG. 3.

Example  5

In Example 5, H ₁₂ MDI is added to produce a high modulus pad.

The same procedure as in Example 1 was carried out except that H ₁₂ MDI was added to L325 to prepare a prepolymer having an NCO% of 12%. The storage modulus and tan delta of the pads prepared in Example 5 are shown in FIG. 3.

Example  6

First, 1000 g of prepolymer, 300 g of octane, and 100 g of dodecane were added to a 50 ° C reactor and mixed for 2 minutes. At this time, octane and dodecane are dispersed in the prepolymer to form spherical droplets (1 to 100 micrometers) in the prepolymer. Thereafter, 260 g of MOCA (methylenebis (2-chloroaniline)) was added and mixed together. The prepared polyurethane mixture was poured into a mold and gelled at room temperature for 1 hour and then cured in an oven at 100 ° C. for 24 hours. The experimental procedure after curing was the same as in Example 1. The pores of the pads thus prepared were 10 to 70 micrometers in size.

Example  7

The pad sheet cured in the same manner as in Example 1 was placed in a supercritical extraction device. The temperature was 50 ° C. and the pressure was maintained at 150 bar. After holding for 1 hour, the pressure was released and the sheet was taken out to remove all CO ₂ from the 100 ° C. oven. The specific gravity of the pad prepared as described above was 0.75 g / cm ³ .

3 shows the experimental results of Examples 1 and 3 to 5 (storage modulus and tan delta were measured), and the storage modulus and tan delta of FIG. 3. The specific measurement method of is as follows. DMA8000 (manufactured by PerkinElmer) was used to measure storage modulus and tan delta, frequency was 1.5 Hz, amplitude was 0.05 mm, and temperature was -10. The scan was from 100 ° C. to 100 ° C.

As shown in FIG. 3, the storage modulus of the sample prepared in Example 1 (NCO% 9.17) was measured to show 396.5 MPa at 25 ° C. FIG.

In addition, the storage modulus was 446.8, 580.3, and 698.4 MPa in the case of increasing the NCO% to 9.7, 11, and 12% by adding H ₁₂ MDI, and increasing the storage modulus by increasing the NCO%. Could increase.

On the other hand, as shown in Figure 3, the tan delta (tan delta) has shown a tendency to decrease on the contrary because the storage modulus increased.

Comparative example

First, 1000 g of L325 (NCO% 9.17%, manufactured by Chemtura) as a prepolymer was placed in a 50 ° C reactor and mixed for 5 minutes. Thereafter, 260 g of MOCA (methylenebis (2-chloroaniline)) was added and mixed together. The prepared polyurethane mixture was poured into a mold and gelled at room temperature for 1 hour and then cured in an oven at 100 ° C. for 24 hours.

The cured polyurethane mixture was cut thin to 3 mm thick and placed in a supercritical foaming device. The temperature of the supercritical foamer was 45 ° C. and carbon dioxide was pressurized into the device to maintain the pressure at 150 bar. The pressure was released after holding in the apparatus for 1 hour. Polyurethane samples were removed from the apparatus, kept at room temperature for 1 hour, and then maintained at 100 ° C. for 1 hour.

SEM image of the sheet according to the comparative example, as a result it was confirmed that the crack occurred through FIG. As described above, when foaming the polyurethane having a high degree of curing by using the pressurized gas method, it was confirmed that the polymer matrix was broken as shown in FIG. 4.

Claims (17)

a) preparing a polymer resin sheet comprising a supercritical extract object soluble in a supercritical fluid; And
b) injecting a supercritical fluid into the polymer resin sheet to extract the supercritical extract contained in the polymer resin sheet to form pores in the polymer resin sheet,
Step a) comprises the steps of a1) mixing the supercritical extract and a prepolymer of a polymer resin; And a2) curing the mixture mixed in the step a1). The method of claim 1, wherein the supercritical extract object comprises one or more selected from aromatic compounds, aliphatic hydrocarbons and aliphatic alcohols. The method of claim 1, wherein the polymer resin sheet of step a) is polyurethane, thermoplastic elastomer, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastomeric rubber, styrene-based copolymer, polyaromatic, fluoropolymer, polyimide, crosslinking Bound polyurethanes, crosslinked polyolefins, polyethers, polyesters, polyacrylates, elastomeric polyethylenes, polytetrafluoroethylenes, polyethyleneterraphthalates, polyarylenes, polystyrenes, polymethylmethacrylates, copolymers thereof, and A block copolymer, and a method for producing a porous sheet comprising a polymer resin selected from the group consisting of mixtures and blends thereof. delete The method of claim 1, wherein in step a1), 1,4-butanediol (1,4-butandiol), 4,4'-methylenebis (2-chloroaniline) (4,4'-methylenebis (2-chloroaniline)), Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol , 2,2,4-trimethylpetanediol, hydroquinone, bis (2-hydroxyethyl) hydroquinone, 4,4'-dihydroxybiphenyl, bisphenol A, bisphenol F, and mixtures thereof The method of manufacturing a porous sheet further comprising adding at least one selected chain extender. The method of claim 1, wherein in the step a2) it is cured for 4 to 48 hours at 70 to 100 ℃. The method of claim 1, wherein the content of the supercritical extract in the polymer resin sheet of step a) is 5 to 50% by weight. The porous sheet of claim 1, wherein the supercritical fluid of step b) comprises at least one selected from supercritical carbon dioxide, supercritical isobutane, supercritical butane, supercritical propane, supercritical pentane, and supercritical nitrogen. Manufacturing method. The method of claim 1, wherein the step b) is carried out at a pressure of 50 to 300 atm and a temperature of 25 to 120 ℃. The method of claim 1, wherein the average diameter of the pores formed in the polymer resin sheet in step b) is 80 micrometers or less. The method according to claim 1, wherein the density of the sheet in which the pores are formed in the polymer resin sheet in step b) is 0.5 to 1g / cm 3 Method for producing a porous sheet. The method of claim 1, wherein the polymer resin sheet in which the pores are formed in step b) has a porosity of 50% or less. Porous sheet produced by the manufacturing method according to any one of claims 1 to 3, and 5 to 12. delete delete Polishing pad comprising a porous sheet according to claim 13. delete

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