JP7004859B2 - Filtration filter and filtration method, and method for manufacturing refined chemical products for lithography - Google Patents

Description

The present invention relates to a filtration filter and a filtration method, and a method for manufacturing a chemical solution refined product for lithography.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed, and a development process is performed to form a resist pattern having a predetermined shape on the resist film. The forming process is performed. A resist material whose exposed portion of the resist film changes to a characteristic that dissolves in a developing solution is called a positive type, and a resist material whose exposed portion of a resist film changes to a characteristic that does not dissolve in a developing solution is called a negative type.
In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, pattern miniaturization is rapidly progressing due to advances in lithography technology. As a method for miniaturizing a pattern, generally, the wavelength of an exposure light source is shortened (energy is increased). Specifically, in the past, ultraviolet rays typified by g-rays and i-rays were used, but nowadays, mass production of semiconductor devices using KrF excimer lasers and ArF excimer lasers is being carried out. Further, studies have been conducted on EUV (extreme ultraviolet rays) having a shorter wavelength (high energy) than these excimer lasers, EB (electron beam), X-rays, and the like.
The resist material is required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing fine dimensional patterns.
Conventionally, as a resist material satisfying such a requirement, a chemically amplified resist composition containing a base material component whose solubility in a developing solution is changed by the action of an acid and an acid generator component that generates an acid by exposure. Things are used.

As the pattern miniaturization progresses, the resist material is required to improve various lithography characteristics and suppress the occurrence of defects (surface defects).
Here, "defect" refers to all defects detected when the resist pattern after development is observed from directly above by, for example, a surface defect observation device (trade name "KLA") manufactured by KLA Corporation. .. This defect is, for example, a defect due to adhesion of foreign matter or precipitates to the surface of the resist pattern such as scum (resist residue), bubbles, dust, etc. after development, a bridge between line patterns, and filling of holes in the contact hole pattern. It refers to defects related to the pattern shape, uneven color of the pattern, etc.

In addition, in the resist material, there is also a problem of foreign matter aging characteristics (one of storage stability) in which fine particle-like foreign matter is generated during storage of the resist solution (resist composition in a solution state), and its improvement. Is desired.

Conventionally, in the production of a resist composition, in order to remove foreign substances, purification is generally performed by passing the resist composition through a filtration filter. However, the conventionally used method of passing the resist composition through a membrane filter or a depth filter is insufficient to suppress the occurrence of the defect of the resist pattern after development.
A step of passing a filter made of nylon and a step of passing a filter made of a polyolefin resin or a fluororesin are performed in response to the above-mentioned suppression of the occurrence of the defect of the resist pattern and the requirement for the foreign matter characteristics of the resist material over time. A method for producing a resist composition having both of them has been proposed (see Patent Document 1).

Further, various lithographic chemicals such as a resin solution containing a resin, a developing solution, a resist solvent, and a pre-wet solvent are used for forming the resist pattern. As a method for removing foreign substances (impurities) such as particles mixed in these chemicals, a method using a filtration filter has been conventionally adopted.
As the pattern becomes finer, the influence of impurities present in these chemicals also appears in the pattern formation.

Japanese Patent No. 4637476

With the further progress of lithography technology and the miniaturization of resist patterns, defects such as scum and microbridge generation after development become a remarkable problem when forming resist patterns with a size of tens to hundreds of nanometers. Therefore, more than ever, there is a need for a technique capable of suppressing the occurrence of defects in the resist pattern after development.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a filtration filter and a filtration method capable of further removing impurities, and a method for producing a chemical solution refined product for lithography in which impurities are further reduced. do.

According to the study, the present inventors have conventionally used a chemical solution for lithography such as a resist composition, a developing solution, a solvent for resist, and a pre-wet solvent by passing it through a filter provided with a polyimide resin porous film to purify it. We have found that the generation of fine particles of foreign matter during storage is significantly suppressed (the characteristics of foreign matter over time are significantly improved) as compared with the case of purifying by passing through a membrane filter or a depth filter, and the present invention has been developed. It came to be completed.

That is, the filtration filter of the first aspect of the present invention is provided with a polyimide-based resin porous membrane and is characterized in that it is used for filtering a chemical solution for lithography.

The filtration method of the second aspect of the present invention is characterized by including an operation of passing a chemical solution for lithography through the filtration filter of the first aspect.

The method for producing a lithographic chemical solution refined product according to a third aspect of the present invention is characterized by comprising a step of filtering the lithographic chemical solution by the filtration method according to the second aspect.

According to the filtration filter according to the present invention, impurities such as particles mixed in a chemical solution or the like can be further removed.
According to the filtration method according to the present invention, impurities such as particles mixed in the chemical solution and the like can be further removed.
According to the method for manufacturing a lithographic chemical refined product according to the present invention, it is possible to manufacture a lithographic chemical refined product with further reduced impurities. By using the resist composition refined product which is the chemical refined product, in the formation of the resist pattern, the generation of defects is further suppressed, and defects such as scum and microbridge generation are reduced, and a resist pattern having a good shape can be obtained. Can be formed.

It is a figure which showed typically one embodiment of the communication hole which constitutes a polyimide resin porous membrane. It is an SEM image which observed the surface of the polyimide resin porous membrane of this embodiment with a scanning electron microscope. It is an SEM image which observed the surface of the porous film made of polyamide (nylon) by a scanning electron microscope. It is an SEM image which observed the surface of a polyethylene porous membrane with a scanning electron microscope.

In the present specification and claims, "aliphatic" is defined as a relative concept to aromatics and means a group, a compound or the like having no aromaticity.
Unless otherwise specified, the "alkyl group" shall include linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
Unless otherwise specified, the "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The "alkyl halide group" is a group in which a part or all of the hydrogen atom of the alkyl group is substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which a part or all of the hydrogen atom of the alkyl group or the alkylene group is substituted with a fluorine atom.
The “constituent unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
"Exposure" is a concept that includes general irradiation of radiation.

The term "styrene" includes styrene and those in which the hydrogen atom at the α-position of styrene is substituted with another substituent such as an alkyl group, an alkyl halide group, or a hydroxyalkyl group.
The "styrene derivative" is a concept including a hydrogen atom at the α-position of styrene substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. Examples of these derivatives include those in which a substituent is bonded to a benzene ring of hydroxystyrene in which a hydrogen atom at the α-position may be substituted with a substituent.
The α-position (carbon atom at the α-position) refers to a carbon atom to which a benzene ring is bonded, unless otherwise specified.

The alkyl group as the substituent at the α-position is preferably a linear or branched alkyl group, and specifically, an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group). , N-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.
Further, the alkyl halide group as the substituent at the α-position is specifically a group in which a part or all of the hydrogen atom of the above-mentioned "alkyl group as the substituent at the α-position" is substituted with a halogen atom. Be done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable.
Further, as the hydroxyalkyl group as the substituent at the α-position, specifically, a group in which a part or all of the hydrogen atom of the above-mentioned "alkyl group as the substituent at the α-position" is substituted with a hydroxyl group can be mentioned. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, most preferably 1.

(Filtration filter)
The filtration filter of the first aspect of the present invention includes a polyimide-based resin porous membrane and is a suitable filter medium for filtering a chemical solution for lithography.

<Chemical solution for lithography>
The chemical solution for lithography, which is the object to be filtered, is not particularly limited, and is, for example, various chemical solutions used when manufacturing a semiconductor element or a liquid crystal display element by a technique of photolithography, DSA lithography, or imprint lithography, or a raw material thereof. Various chemicals are mentioned.
Examples of the chemical solution include those containing water; a polar solvent such as a ketone solvent, an ester solvent, an alcohol solvent, an ether solvent, and an amide solvent; and a hydrocarbon solvent. Further, as a chemical solution for lithography containing a resin, a resin solution in which a resin component for resist is dissolved in an organic solvent component, a resist composition described later, an insulating film composition, an antireflection film composition, and directed self-assembly (Directed Self Assembly). : DSA) Examples include block copolymer compositions applied to technology, resin compositions for imprinting, and the like. In addition, examples of the lithographic chemical solution used for pattern formation and the like include a pre-wet solvent, a resist solvent, a developing solution and the like.

Examples of the ketone solvent include 1-octanone, 2-octanone, 1-nonanonone, 2-nonanonone, acetone, 2-heptanone (methylamylketone), 4-heptanone, 1-hexanone, 2-hexanone, and diisobutyl. Examples thereof include ketones, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthylketone, isophorone, propylene carbonate and the like.
Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, pentyl acetate, isopentyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and diethylene glycol monoethyl. Ether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl formic acid, ethyl forerate, butyl formic acid, propyl formic acid, ethyl lactate, butyl lactate, propyl lactate, etc. Can be mentioned.
Examples of the alcohol-based solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, and n-heptyl alcohol. Alcohols such as n-octyl alcohol and n-decanol; glycol-based solvents such as ethylene glycol, diethylene glycol and triethylene glycol; ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether and diethylene glycol monomethyl Examples thereof include glycol ether-based solvents such as ether, triethylene glycol monoethyl ether and methoxymethylbutanol.
Examples of the nitrile-based solvent include organic solvents containing a nitrile group in the structure, for example, acetonitrile.
Examples of the ether solvent include dioxane, tetrahydrofuran and the like in addition to the above glycol ether solvent.
Examples of the amide solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, 1,3-dimethyl-2-imidazolidinone and the like. Can be mentioned.
Examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as toluene and xylene; and aliphatic hydrocarbon solvents such as pentane, hexane, octane and decane.

As the resin component for resist, the component (A1) described later (a polymer compound having a structural unit (ap) containing a polar group) is preferable.

The resist composition to be filtered includes, for example, a base material component (A) whose solubility in a developing solution changes due to the action of an acid (hereinafter referred to as “(A) component”) and an organic solvent component (S) (. Hereinafter, those containing "(S) component") and having an acid generating ability can be mentioned.

Examples of such a resist composition include those having an acid-generating ability to generate an acid by exposure, and the component (A) may generate an acid by exposure, and an addition compounded separately from the component (A) may be used. The agent component may generate an acid upon exposure.
Specifically, such a resist composition is used.
(1) It may contain an acid generator component (B) (hereinafter referred to as "(B) component") that generates an acid by exposure.
(2) The component (A) may be a component that generates an acid by exposure.
(3) The component (A) may be a component that generates an acid by exposure and may further contain a component (B).
That is, in the case of the above (2) and (3), the component (A) is "a base material component that generates an acid by exposure and whose solubility in a developing solution is changed by the action of the acid". When the component (A) is a base material component that generates an acid by exposure and whose solubility in a developer changes due to the action of the acid, the component (A1) described later generates an acid by exposure and the solubility in the developer changes. It is preferably a polymer compound whose solubility in a developing solution changes due to the action of an acid. As such a polymer compound, a resin having a structural unit that generates an acid upon exposure can be used. As the structural unit that generates an acid by exposure, a known one can be used. Above all, the resist composition of the present invention is preferably the case of (1) above.

-Regarding the component (A) In the present invention, the "base component" is an organic compound having a film-forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film forming ability is improved, and in addition, a nano-level resist pattern is easily formed.
Organic compounds used as base material components are roughly classified into non-polymers and polymers.
As the non-polymer, one having a molecular weight of 500 or more and less than 4000 is usually used. Hereinafter, the term "small molecule compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, a polymer having a molecular weight of 1000 or more is usually used. Hereinafter, the term "resin" or "polymer compound" indicates a polymer having a molecular weight of 1000 or more.
As the molecular weight of the polymer, the mass average molecular weight in terms of polystyrene by GPC (gel permeation chromatography) shall be used.

When the resist composition is a "negative resist composition for an alkali developing process" that forms a negative resist pattern in an alkali developing process, or a "positive for a solvent developing process" that forms a positive resist pattern in a solvent developing process. In the case of "type resist composition", as the component (A), a substrate component (A-2) soluble in an alkaline developer (hereinafter referred to as "component (A-2)") is preferably used. Further, a cross-linking agent component is blended. In such a resist composition, for example, when an acid is generated from the component (B) by exposure, the acid acts to cause cross-linking between the component (A-2) and the cross-linking agent component, resulting in alkaline development. Solubility in liquid decreases (solubility in organic developer increases). Therefore, in forming a resist pattern, when the resist film obtained by applying the resist composition on a support is selectively exposed, the exposed portion is sparingly soluble in an alkaline developing solution (relative to an organic developing solution). On the other hand, the unexposed part remains soluble in the alkaline developing solution (slightly soluble in the organic developing solution) and does not change. Therefore, a negative resist pattern is formed by developing with the alkaline developing solution. To. Further, at this time, a positive resist pattern is formed by developing with an organic developer.
As the preferred component (A-2), a resin soluble in an alkaline developer (hereinafter referred to as "alkali-soluble resin") is used.
As the cross-linking agent component, for example, it is usually preferable to use an amino-based cross-linking agent such as glycoluryl having a methylol group or an alkoxymethyl group, a melamine-based cross-linking agent, or the like, because a good resist pattern with less swelling can be formed. The blending amount of the cross-linking agent component is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the alkali-soluble resin.

When the resist composition is a "positive resist composition for an alkali developing process" that forms a positive resist pattern in an alkali developing process, or a "negative for a solvent developing process" that forms a negative resist pattern in a solvent developing process. In the case of "type resist composition", as the component (A), a substrate component (A-1) whose polarity is increased by the action of an acid (hereinafter referred to as "component (A-1)") is preferably used. Be done. By using the component (A-1), the polarity of the base material component changes before and after exposure, so that good development contrast can be obtained not only in the alkaline development process but also in the solvent development process.
When the alkaline developing process is applied, the component (A-1) is sparingly soluble in an alkaline developer before exposure. For example, when an acid is generated from the component (B) by exposure, the action of the acid causes the component (B). The polarity increases and the solubility in alkaline developers increases. Therefore, in the formation of a resist pattern, when the resist composition is selectively exposed to a resist film obtained by applying the resist composition on a support, the exposed portion changes from sparingly soluble to an alkaline developer to be soluble in an alkaline developer. Since the unexposed portion remains sparingly soluble in alkali, a positive resist pattern is formed by developing with alkali.
On the other hand, when a solvent developing process is applied, the component (A-1) has high solubility in an organic developer before exposure, and when acid is generated by exposure, the polarity is high due to the action of the acid. Therefore, the solubility in an organic developer is reduced. Therefore, in forming a resist pattern, when the resist composition is selectively exposed to a resist film obtained by applying the resist composition on a support, the exposed portion changes from soluble to sparingly soluble in an organic developer. On the other hand, since the unexposed portion remains soluble and does not change, it is possible to add contrast between the exposed portion and the unexposed portion by developing with an organic developer, and a negative resist pattern is formed.

The component (A) used in the resist composition of the present invention includes a structural unit (a1) containing an acid-degradable group whose polarity is increased by the action of an acid, a structural unit (a2) containing a lactone-containing cyclic group, and a polarity. A structural unit containing a group-containing aliphatic hydrocarbon group (a3), a structural unit containing an acid non-dissociable cyclic group (a4), a carbonate-containing cyclic group, or a structural unit containing a _—SO2 -containing cyclic group ( A resin component having a5) or the like is preferable.

・ ・ Structural unit (a1)
The structural unit (a1) is a structural unit containing an acid-degradable group whose polarity is increased by the action of an acid.
An "acid-degradable group" is a group having an acid-degradable property in which at least a part of the bonds in the structure of the acid-degradable group can be cleaved by the action of an acid.
Examples of the acid-degradable group whose polarity is increased by the action of an acid include a group which is decomposed by the action of an acid to form a polar group.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (-SO _3H ) and the like. Among these, a polar group containing —OH in the structure (hereinafter, may be referred to as “OH-containing polar group”) is preferable, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable.
More specifically, the acid-degradable group includes a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid-dissociable group).
Here, the term "acid dissociative group" is used.
(I) A group having acid dissociation that allows the bond between the acid dissociating group and an atom adjacent to the acid dissociating group to be cleaved by the action of an acid, or a group having acid dissociation.
(Ii) A group capable of cleaving the bond between the acid dissociative group and an atom adjacent to the acid dissociative group by further decarbonation reaction after the partial bond is cleaved by the action of the acid. ,
Refers to both.
The acid dissociative group constituting the acid-degradable group needs to be a group having a lower polarity than the polar group produced by the dissociation of the acid dissociative group, whereby the acid dissociative group is affected by the action of the acid. When is dissociated, a polar group having a higher polarity than the acid dissociative group is generated and the polarity is increased. As a result, the polarity of the entire component (A) increases. As the polarity increases, the solubility in the developer changes relatively, the solubility in the developer increases in the case of the alkaline developer, and the solubility in the developer in the case of the organic developer. Decrease.

The acid dissociative group is not particularly limited, and those previously proposed as an acid dissociative group of the base resin for a chemically amplified resist can be used.

The structural unit (a1) contained in the component (A) may be one kind or two or more kinds.
The ratio of the constituent unit (a1) in the component (A) is preferably 20 to 80 mol%, more preferably 20 to 75 mol%, and 25 to 25 to the total of all the constituent units constituting the component (A). 70 mol% is more preferred.

・ ・ Structural unit (a2)
The structural unit (a2) is a structural unit containing a lactone-containing cyclic group (however, excluding those corresponding to the above-mentioned structural unit (a1)).
The lactone-containing cyclic group of the structural unit (a2) is effective in enhancing the adhesion of the resist film to the substrate when the component (A) is used for forming the resist film.

The “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —O—C (= O) —in its ring skeleton. The lactone ring is counted as the first ring, and when it has only a lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of its structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

The structural unit (a2) contained in the component (A) may be one kind or two or more kinds.
The ratio of the constituent unit (a2) in the component (A) is preferably 1 to 80 mol%, more preferably 5 to 70 mol%, and 10 to 10 to the total of all the constituent units constituting the component (A). 65 mol% is more preferable, and 10 to 60 mol% is particularly preferable.

・ ・ Structural unit (a3)
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (however, excluding those corresponding to the above-mentioned structural units (a1) and (a2)).
Since the component (A) has the structural unit (a3), the hydrophilicity of the component (A) is enhanced, which contributes to the improvement of the resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, a hydroxyalkyl group in which a part of the hydrogen atom of the alkyl group is replaced with a fluorine atom, and the like, and a hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group, and for example, in the resin for the resist composition for ArF excimer laser, it can be appropriately selected from a large number of proposed ones and used. The cyclic group is preferably a polycyclic group, and more preferably 7 to 30 carbon atoms.

The structural unit (a3) contained in the component (A) may be one kind or two or more kinds.
The ratio of the constituent unit (a3) in the component (A) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, and 5 to 5 to the total of all the constituent units constituting the component (A). 25 mol% is more preferred.

・ ・ Structural unit (a4)
The structural unit (a4) is a structural unit containing an acid non-dissociative cyclic group.
Since the component (A) has the structural unit (a4), the dry etching resistance of the formed resist pattern is improved.
The "acid non-dissociative cyclic group" in the structural unit (a4) is a ring that remains in the structural unit as it is without dissociation even if the acid acts when an acid is generated from the component (B) by exposure. It is a formula base.
The ratio of the constituent unit (a4) in the component (A) is preferably 1 to 30 mol%, more preferably 10 to 20 mol%, based on the total of all the constituent units constituting the component (A).

・ ・ Structural unit (a5)
The structural unit (a5) is a structural unit containing a _—SO2 -containing cyclic group or a carbonate-containing cyclic group.

The "-SO ₂ -containing cyclic group" refers to a cyclic group containing a ring containing -SO _2- in its ring skeleton, and specifically, the sulfur atom (S) in -SO _2- A cyclic group that forms part of the cyclic skeleton of the cyclic group. A ring containing -SO _2- in its ring skeleton is counted as the first ring, and if it is only the ring, it is a monocyclic group, and if it has another ring structure, it is a polycyclic group regardless of its structure. It is called. -SO ₂ -The contained cyclic group may be monocyclic or polycyclic.
-SO ₂ -containing cyclic groups are particularly cyclic groups containing -O-SO ₂ -in their cyclic skeleton, that is, -OS- in -O-SO _2- contains a part of the cyclic skeleton. It is preferably a cyclic group containing a sultone ring to be formed.

The “carbonate-containing cyclic group” refers to a cyclic group containing a ring (carbonate ring) containing —O—C (= O) —O— in its cyclic skeleton. The carbonate ring is counted as the first ring, and when it has only a carbonate ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of its structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.

The structural unit (a5) contained in the component (A) may be one kind or two or more kinds.
The ratio of the constituent unit (a5) in the component (A) is preferably 1 to 80 mol%, more preferably 5 to 70 mol%, and 10 to 65 with respect to the total of all the constituent units constituting the component (A). More preferably, 10-60 mol% is particularly preferable.

In the resist composition of the present invention, the component (A) preferably contains a polymer compound (A1) having a structural unit (ap) containing a polar group (hereinafter, also referred to as “component (A1)”). In this case, the effect of the present invention is remarkable.
The polar group in the structural unit (ap) includes a hydroxyl group, a cyano group, a carboxy group, a sulfo group, a hydroxyalkyl group in which a part of the hydrogen atom of the alkyl group is replaced with a fluorine atom, and a carbonyl group (-C (= O)). -), Carbonyl group (-C (= O) -O-), carbonate group (-OC (= O) -O-), sulfonyl group (-S (= O) _2- ), sulfonyloxy group (-S (= O) ₂ -O-) and the like can be mentioned.

Preferred (A1) components include, for example, polymer compounds having a structural unit (a1). As the component (A1), specifically, a polymer compound having a constituent unit (a1) and a constituent unit (a2), a polymer compound having a constituent unit (a1) and a constituent unit (a3), and a constituent unit ( A polymer compound having a1) and a constituent unit (a5), a polymer compound having a constituent unit (a1), a constituent unit (a2) and a constituent unit (a3), a constituent unit (a1) and a constituent unit (a3). And a polymer compound having a structural unit (a5).

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (A) is not particularly limited, and is preferably 1000 to 50000, more preferably 1500 to 30000, and particularly 2000 to 20000. preferable.

In the resist composition of the present invention, the component (A) may be used alone or in combination of two or more.
The content of the component (A) in the resist composition of the present invention may be adjusted according to the resist film thickness to be formed and the like.

-Regarding the component (S) The resist composition in the present invention can be prepared by dissolving the resist material in the organic solvent component (component (S)).
The component (S) may be any component as long as it can dissolve each component to be used to form a uniform solution, and any conventionally known solvent for the chemically amplified resist composition may be appropriately used. It can be selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; and many such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol. Hyvalent alcohols; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, monomethyl ethers of the polyhydric alcohols or compounds having the ester bond, monoethyl. Derivatives of polyhydric alcohols such as monoalkyl ethers such as ethers, monopropyl ethers and monobutyl ethers or compounds having an ether bond such as monophenyl ethers [among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl Ethers (PGME) are preferred]; cyclic ethers such as dioxane, methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxy Esters such as ethyl propionate; anisole, ethylbenzyl ether, cresylmethyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, simene, mesitylen, etc. Examples thereof include aromatic organic solvents and dimethyl sulfoxide (DMSO).
The component (S) may be used alone or as a mixed solvent of two or more kinds.
For example, a mixed solvent in which PGMEA and a polar solvent are mixed is preferable.
The amount of the component (S) used is not particularly limited, and is appropriately set according to the coating film thickness at a concentration that can be applied to a substrate or the like. Generally, the component (S) is used so that the solid content concentration of the resist composition is preferably in the range of 1 to 20% by mass, more preferably 2 to 15% by mass.

-Regarding optional components In the resist composition in the present invention, in addition to the components (A) and (S), an acid generator component (B) ((B) component) that generates an acid by exposure and an acid diffusion control agent (hereinafter referred to as an acid diffusion control agent). At least one compound (E) selected from the group consisting of "component (D)"), an organic carboxylic acid, an oxo acid of phosphorus and a derivative thereof (hereinafter referred to as "component (E)"), and fluorine addition. An agent (hereinafter referred to as "component (F)") or the like may be contained.

-Regarding the component (B) The component (B) is an acid generator component that generates an acid by exposure.
The component (B) is not particularly limited, and those previously proposed as an acid generator for a chemically amplified resist can be used.
Examples of the component (B) include onium salt-based acid generators such as iodonium salt and sulfonium salt, oxime sulfonate-based acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and diazomethane-based poly (bissulfonyl) diazomethanes. Examples thereof include acid generators, nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, and disulfonate-based acid generators. Above all, it is preferable to use an onium salt-based acid generator.

In the resist composition of the present invention, the component (B) may be used alone or in combination of two or more.
When the resist composition contains the component (B), the content of the component (B) is preferably 0.5 to 60 parts by mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the component (A). 1 to 40 parts by mass is more preferable. By setting the content of the component (B) in the above range, pattern formation is sufficiently performed. Further, when each component of the resist composition is dissolved in an organic solvent, a uniform solution can be easily obtained, and the storage stability becomes better.

-Regarding the component (D) The component (D) is an acid diffusion control agent component.
The component (D) acts as a citric acid that traps the acid generated by exposure from the component (B) and the like.
The component (D) may be a photodisintegrating base (D1) (hereinafter referred to as “(D1) component”) that is decomposed by exposure and loses acid diffusion controllability, or is a nitrogen-containing organic substance that does not correspond to the component (D1). Compound (D2) (hereinafter referred to as “(D2) component”) may be used.

The content of the component (D1) is preferably 0.5 to 10.0 parts by mass, more preferably 0.5 to 8.0 parts by mass, and 1.0 to 8. 0 parts by mass is more preferable. When it is at least a preferable lower limit value in the above range, particularly good lithography characteristics or resist pattern shape can be easily obtained. When it is not more than the preferable upper limit value in the above range, the sensitivity can be maintained well and the throughput is also excellent.

As the component (D2), an aliphatic amine, particularly a secondary aliphatic amine or a tertiary aliphatic amine is preferable. The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkylamine or alkylalcoholamine) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms, or a cyclic amine.
The content of the component (D2) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A). Within the above range, the shape of the resist pattern, stability over time, and the like are improved.

In the resist composition of the present invention, the component (D) may be used alone or in combination of two or more.
When the resist composition contains the component (D), the content of the component (D) is preferably 0.1 to 15 parts by mass, preferably 0.3 to 12 parts by mass with respect to 100 parts by mass of the component (A). More preferably, 0.5 to 12 parts by mass is further preferable. When it is at least a preferable lower limit value in the above range, the lithography characteristics such as LWR are further improved when the resist composition is prepared. Moreover, a better resist pattern shape can be obtained. When it is not more than the preferable upper limit value in the above range, the sensitivity can be maintained well and the throughput is also excellent.

-Regarding the component (E) The component (E) is at least one compound selected from the group consisting of an organic carboxylic acid and a phosphorus oxo acid and a derivative thereof. By containing the component (E), it is possible to prevent deterioration of sensitivity and improve the shape of the resist pattern, stability over time, and the like.
In the resist composition of the present invention, the component (E) may be used alone or in combination of two or more.
When the resist composition contains the component (E), the content of the component (E) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A).

-Regarding the component (F) The component (F) is a fluorine additive. By containing the component (F), water repellency is imparted to the resist film.
Examples of the component (F) are described in JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, and JP-A-2011-128226. Fluorine-containing polymer compounds can be mentioned.
In the resist composition of the present invention, the component (F) may be used alone or in combination of two or more.
When the resist composition contains the component (F), the content of the component (F) is used in the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the component (A).

The resist composition may further include, if desired, miscible additives, such as additional resins for improving the performance of resist films, dissolution inhibitors, surfactants, plasticizers, stabilizers, colorants, anti-halation agents. , Dyes and the like can be appropriately added and contained.

Examples of the insulating film composition to be filtered include a siloxane polymer, an organic hydride siloxane polymer, an organic hydride silsesquioxane polymer, or a copolymer of hydrogensil sesquioxane and an alkoxyhydride siloxane or hydroxyhydride siloxane. Examples thereof include a liquid containing an organic solvent component.
Examples of the insulating film composition include a liquid containing a silsesquioxane resin, an acid generator component that generates an acid upon exposure, a cross-linking agent component, and an organic solvent component.

As the antireflection film composition to be filtered, a composition containing a film constituent material of the antireflection film and an organic solvent component is used. The film constituent material may be an organic material or an inorganic material containing Si atoms, and mainly contains a binder component such as a resin and / or a cross-linking agent, and an absorbent component that absorbs a specific wavelength such as ultraviolet rays. Can be mentioned. Each of these components may be used alone as a film-constituting material, or two or more kinds (that is, a resin and a cross-linking agent, a cross-linking agent and an absorbent component, a resin and an absorbent component, and a resin and a cross-linking agent and an absorbent component). ) May be combined to form a film constituent material. In addition, a surfactant, an acid compound, an acid generator, a cross-linking accelerator, a rheology adjuster, an adhesion aid and the like may be added to the antireflection film composition, if necessary.
The antireflection film composition to be filtered includes, for example, a polyfunctional epoxy compound having a plurality of epoxy portions in the side chain of the core unit and having one or more crosslinkable chromophores bonded thereto, and vinyl ether. Examples thereof include a liquid containing a cross-linking agent and an organic solvent component.
The "epoxy moiety" refers to at least one of a closed epoxide ring and a ring-opened (reacted) epoxy group, such as a reacted or unreacted glycidyl group, a glycidyl ether group, etc.
"Crosslinkable chromophore" refers to a photodamn moiety having a crosslinkable group that is free (ie, unreacted) after the chromophore has been attached to the polyfunctional epoxy compound.

Examples of the monomer for inducing the core unit include tris (2,3-epoxypropyl) isocyanurate, tris (4-hydroxyphenyl) methanetriglycidyl ether, trimethylopropane triglycidyl ether, and poly (ethylene glycol) di. Glycyzyl ether, bis [4- (glycidyloxy) phenyl] methane, bisphenol A diglycidyl ether, 1,4-butanediol diglycidyl ether, resorcinol diglycidyl ether, 4-hydroxybenzoate diglycidyl ether, glycerol diglycidyl ether, 4,4'-Methylenebis (N, N-diglycidylaniline), monoaryldiglycidyl isocyanurate, tetrakis (oxylanylmethyl) benzene-1,2,4,5-tetracarboxylate, bis (2,3-) Those containing polyfunctional glycidyl such as epoxypropyl) terephthalate or tris (oxylanylmethyl) benzene-1,2,4-tricarboxylate; 1,3-bis (2,4-bis (glycidyloxy) phenyl) Adamantin, 1,3-bis (1-adamantyl) -4,6-bis (glycidyloxy) benzene, 1- (2', 4'-bis (glycidyloxy) phenyl) adamantan or 1,3-bis (4') -Glysidyloxyphenyl) adamantan; poly [(phenylglycidyl ether) -co-formaldehyde], poly [(o-cresylglycidyl ether) -co-formaldehyde], poly (glycidyl methacrylate), poly (bisphenol A-co-epi) Examples include polymers such as chlorohydrin) -glycidyl endcaps, poly (styrene-co-glycidyl methacrylate) or poly (tert-butyl methacrylate-co-glycidyl methacrylate).

Examples of the precursor (compound before binding) of the color-developing group include 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 6-hydroxy-2-naphthoic acid, and 3-hydroxy-2-. Naftoic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 1,1'-methylene-bis (2-hydroxy-3) -Naftoeic acid), 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,5-dihydroxy Examples thereof include -4-methylbenzoic acid, 3-hydroxy-2-anthracenecarboxylic acid, 1-hydroxy-2-anthracenecarboxylic acid, 3-hydroxy-4-methoxymandelic acid, galvanic acid or 4-hydroxybenzoic acid.

Examples of the block copolymer composition applied to the DSA technique of the object to be filtered include a liquid containing a block copolymer and an organic solvent component.
As the block copolymer, for example, a polymer compound in which a hydrophobic polymer block (b11) and a hydrophilic polymer block (b21) are bonded can be preferably used.
As the hydrophobic polymer block (b11) (hereinafter, also simply referred to as “block (b11)”), a plurality of monomers having relatively different affinities with water are used, and among these a plurality of monomers, the affinity with water is used. A block made of a polymer (hydrophobic polymer) in which a monomer having a relatively lower property is polymerized. The hydrophilic polymer block (b21) (hereinafter, also simply referred to as “block (b21)”) is a polymer obtained by polymerizing the monomer having a relatively high affinity with water among the plurality of monomers (hydrophilic polymer). ) Is a block.

The block (b11) and the block (b21) are not particularly limited as long as they are a combination in which phase separation occurs, but a combination of blocks that are incompatible with each other is preferable.
Further, in the block (b11) and the block (b21), a phase composed of at least one type of block in a plurality of types of blocks constituting the block copolymer can be easily removed as compared with a phase composed of other types of blocks. It is preferably a combination.
The types of blocks constituting the block copolymer may be two types or three or more types.
The block copolymer may have partial constituents (blocks) other than the block (b11) and the block (b21) bonded to the block copolymer.

As the block (b11) and the block (b21), for example, a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded, and a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent. A block in which a structural unit derived from an acrylic acid ester ((α-substituted) structural unit derived from an acrylic acid ester) is repeatedly bonded, or a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent. It is derived from a block in which a structural unit derived from acrylic acid (a structural unit derived from (α-substituted) acrylic acid) is repeatedly bonded, a block in which a structural unit derived from a siloxane or a derivative thereof is repeatedly bonded, and an alkylene oxide. Examples thereof include a block in which structural units are repeatedly bonded, a block in which structural units containing a silsesquioxane structure are repeatedly bonded, and the like.

Examples of the styrene derivative include those in which the hydrogen atom at the α-position of styrene is substituted with a substituent such as an alkyl group or an alkyl halide group, or derivatives thereof. Examples of these derivatives include those in which a substituent is bonded to a benzene ring of styrene in which a hydrogen atom at the α-position may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group and the like.
Specifically, as the styrene derivative, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, 2,4,6-trimethylstyrene. , 4-Methylstyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene, 4-vinylbenzyl chloride, etc. Can be mentioned.

Examples of the (α-substituted) acrylic acid ester include acrylic acid esters and acrylic acid esters in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group and the like.
(Α Substitution) Specific examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, octyl acrylate, nonyl acrylate, and acrylic. Acrylic acid esters such as hydroxyethyl acrylate, hydroxypropyl acrylate, benzyl acrylate, anthracene acrylate, glycidyl acrylate, 3,4-epoxycyclohexylmethane acrylate, propyltrimethoxysilane acrylate; methyl methacrylate, ethyl methacrylate , Cycyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, nonyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, benzyl methacrylate, anthracene methacrylate, glycidyl methacrylate. , Acrylic esters such as 3,4-epoxycyclohexylmethane methacrylate and propyltrimethoxysilane methacrylate.

Examples of the (α-substituted) acrylic acid include acrylic acid and acrylic acid in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group and the like. Specific examples of the (α-substituted) acrylic acid include acrylic acid and methacrylic acid.

Examples of the siloxane or its derivative include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, and methylphenylsiloxane.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, isopropylene oxide, butylene oxide and the like.
As the silsesquioxane structure-containing structural unit, a cage-type silsesquioxane structure-containing structural unit is preferable. Examples of the monomer that provides the cage-type silsesquioxane structure-containing structural unit include compounds having a cage-type silsesquioxane structure and a polymerizable group.

As such a block copolymer, for example, a polymer in which a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded and a block in which structural units derived from (α-substituted) acrylic acid ester are repeatedly bonded are bonded. Compound; A polymer compound in which a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded and a block in which structural units derived from (α-substituted) acrylic acid are repeatedly bonded are bonded; from a styrene or styrene derivative. A polymer compound in which a block in which a structural unit derived from a derivative is repeatedly bonded and a block in which a structural unit derived from a siloxane or a derivative thereof is repeatedly bonded; a block in which a structural unit derived from an alkylene oxide is repeatedly bonded; , A block in which structural units derived from (α-substituted) acrylic acid ester are repeatedly bonded, and a polymer compound bonded with; a block in which structural units derived from alkylene oxide are repeatedly bonded, and from (α-substituted) acrylic acid. A block in which the induced structural units are repeatedly bonded and a polymer compound to which the compound is bonded; A repeatedly bonded block and a polymer compound bonded to; a block in which cage-type silsesquioxane structure-containing structural units are repeatedly bonded and a block in which structural units derived from (α-substituted) acrylic acid are repeatedly bonded. Bound polymer compound; a polymer compound in which a block in which cage-type silsesquioxane structure-containing structural units are repeatedly bonded and a block in which structural units derived from siloxane or a derivative thereof are repeatedly bonded can be mentioned. ..

Specific examples of such block copolymers include polystyrene-polymethylmethacrylate (PS-PMMA) block copolymers, polystyrene-polyethylmethacrylate block copolymers, polystyrene- (poly-t-butylmethacrylate) block copolymers, and polystyrene-polymethacrylic acid blocks. Examples thereof include polystyrene-polymethyl acrylate block copolymer, polystyrene-polyethyl acrylate block copolymer, polystyrene- (poly-t-butyl acrylate) block copolymer, polystyrene-polyacrylic acid block copolymer and the like.

Examples of the organic solvent component used in the insulating film composition, the antireflection film composition, and the block copolymer composition include the same components as the above-mentioned (S) component.

Examples of the resin composition for imprint to be filtered include a liquid containing a cycloolefin-based copolymer, a polymerizable monomer, a photoinitiator, and an organic solvent component.
Examples of this organic solvent component include halogenated hydrocarbons such as methyl chloride, dichloromethane, chloroform, ethyl chloride, dichloroethane, n-propyl chloride, n-butyl chloride and chlorobenzene; benzene, toluene, xylene, ethylbenzene, propylbenzene and butylbenzene. Alkylbenzenes such as: ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane and other linear aliphatic hydrocarbons; 2-methylpropane, 2-methylbutane, 2,3,3-trimethylpentane , 2,2,5-trimethylhexane and other branched chain aliphatic hydrocarbons; cyclic aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane and decahydroxynaphthalene; Examples include oil.

Examples of the cycloolefin-based copolymer include an amorphous polymer having a structural unit containing a cyclic olefin structure. Specific examples thereof include a copolymer having a structural unit containing a cyclic olefin structure and a structural unit containing a non-cyclic olefin structure.
Examples of the structural unit containing the cyclic olefin structure include a structural unit derived from a diene compound. Examples of the diene compound include 2,5-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, dicyclopentadiene, 5-isopropylidene-2-norbornene, and tri. Cyclopentadiene, 1,4,5,8-dimethano-1,4,4a,5,8,8a-hexahydronaphthalene, cyclopentadiene, 1,4-cyclohexadiene, 1,3-cyclohexadiene, 1,5- Cyclodiene such as cyclooctadiene, 1-vinylcyclohexene, 2-vinylcyclohexene, 3-vinylcyclohexene; 4,5,7,8-tetrahydroindene, 4-methyltetrahydroindene, 6-methyltetrahydroindene or 6-ethyltetrahydro Examples thereof include alkyltetrahydroindene such as indene.
As the structural unit containing the acyclic olefin structure, the structural unit derived from an acyclic monoolefin, for example, an α-olefin having 2 to 20 carbon atoms (preferably ethylene or propylene); an acyclic diene (1, Examples thereof include structural units derived from 5-hexadiene, 1,4-hexadiene, 1,3-hexadiene, 1,9-decadien, butadiene, isoprene, etc.).

As the polymerizable monomer, a monofunctional monomer or a polyfunctional monomer can be used, and examples thereof include a monofunctional monomer, a bifunctional monomer, a trifunctional monomer, a tetrafunctional monomer, a pentafunctional monomer, and the like, and among these, 2 Functional monomers are preferred. As the bifunctional monomer, a bifunctional monomer having an aliphatic cyclic group is preferable, and examples thereof include cyclohexanedimethanol dimethacrylate, cyclohexanedimethanol dimethacrylate, and tricyclodecanedimethanol diacrylate.

The photoinitiator may be any compound that initiates or promotes the polymerization of the cycloolefin-based copolymer upon irradiation with light, for example, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1. -On, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one , 1-Hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexa Fluorophosphate, a mixture of 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and 2- (2-hydroxyethoxy) ethyl ester, phenylglycosylate, benzophenone and the like can be mentioned.

The filtration filter of this embodiment is useful when the chemical solution containing the resin is the object to be filtered. Among these resin-containing chemical solutions, the chemical solution for photolithography, the chemical solution for DSA lithography, and the chemical solution for imprint lithography are more useful when they are the objects to be filtered, and are more useful and are applied to the resist composition and DSA technology. It is particularly useful when the copolymer composition and the resin composition for imprint are the objects to be filtered.

The filtration filter of this embodiment is particularly useful when the chemical solution containing the component (A1) is the object to be filtered among the resist compositions.

Further, among the lithographic chemicals, the filtration filter of this embodiment is also useful when the chemical selected from the group consisting of the prewet solvent, the resist solvent and the developer is the object to be filtered.
Further, in the filtration filter of this embodiment, a filter provided with a polyimide-based resin porous membrane is used, and acid resistance is enhanced, so that it is particularly useful for an object to be filtered (chemical solution for lithography) showing acidity. ..

Examples of the developer include an alkaline developer and a developer containing an organic solvent (organic developer).
Examples of the alkaline developer include a 0.1 to 10 mass% tetramethylammonium hydroxide (TMAH) aqueous solution.
The organic solvent contained in the organic developer may be any one that can dissolve the base material component (base material component before exposure), and can be appropriately selected from known organic solvents. For example, a ketone solvent, an ester solvent, an alcohol solvent, a nitrile solvent, an amide solvent, a polar solvent such as an ether solvent, a hydrocarbon solvent and the like can be mentioned, and specific examples thereof are given above. Be done.

<Filtration filter>
The filtration filter of this embodiment includes a polyimide-based resin porous membrane.
At least a polyimide-based resin porous membrane is used for such a filtration filter, and it may be a single body of the polyimide-based resin porous membrane, or may be one in which another filter medium is used together with the polyimide-based resin porous membrane.
Examples of other filter media include nylon films, polytetrafluoroethylene films, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) films, and films modified thereof.

In the present invention, the "polyimide-based resin" means one or both of polyimide and polyamide-imide. The polyimide and the polyamide-imide may each have at least one functional group selected from the group consisting of a carboxy group, a salt-type carboxy group, and an -NH- bond.

In such a filtration filter, the region of the polyimide-based resin porous membrane before and after passing the liquid is preferably sealed so that the supply liquid of the object to be filtered (chemical liquid for lithography) and the filtrate are separated without being mixed. As a method of this sealing, for example, a polyimide resin porous film is bonded by light (UV) curing, heat bonding (including bonding by anchor effect (heat welding, etc.)), or bonding using an adhesive. Examples thereof include a method of processing, or a method of adhering a polyimide resin porous film and another filter medium by an incorporation method or the like. As such a filtration filter, the above-mentioned polyimide-based resin porous film is provided in an outer container made of a thermoplastic resin (polyethylene, polypropylene, PFA, polyether sulfone (PES), polyimide, polyamide-imide, etc.). Can also be mentioned.
In such a filtration filter, examples of the form of the polyimide-based resin porous membrane include a planar shape and a pipe shape in which the opposite sides of the polyimide-based resin porous membrane are combined. The pipe-shaped polyimide resin porous film preferably has a fold-like surface because the area of contact with the feed solution increases.

-Regarding the Polyimide-based Resin Porous Membrane Examples of the polyimide-based resin porous membrane provided in the filtration filter include those having communication holes.
The communication holes are formed by individual pores (cells) that impart porosity to the polyimide resin porous membrane, and the individual pores are preferably holes having a curved surface on the inner surface. It is more preferably a substantially spherical hole (spherical cell).
In the polyimide-based resin porous membrane, for example, at least a part of communication holes are formed between adjacent holes.

FIG. 1 schematically shows an embodiment of communication holes constituting a polyimide-based resin porous membrane.
In the polyimide-based resin porous membrane of the present embodiment, the spherical cells 1a and the spherical cells 1b have almost the entire inner surface of each curved surface, forming a substantially spherical space.
The spherical cell 1a and the spherical cell 1b are adjacent to each other, and a communication hole 5 through which the overlapping portion Q of the adjacent spherical cell 1a and the spherical cell 1b penetrates is formed. Then, the object to be filtered flows through the communication hole 5 in the direction (arrow direction) from the spherical cell 1a to the spherical cell 1b, for example.

Such communication holes have a structure in which such adjacent holes communicate with each other, and in the polyimide-based resin porous membrane, such a plurality of holes are connected to form a flow path of an object to be filtered as a whole. It is preferable that it is.
The "flow path" is usually formed by communicating individual "holes" and / or "communication holes" with each other. The individual pores are formed, for example, by removing the individual fine particles present in the polyimide resin-fine particle composite film in the method for producing a polyimide resin porous film described later in a subsequent step. Further, in the communication hole, in the method for producing a polyimide resin porous membrane described later, the fine particles are removed in a subsequent step at a portion existing in the polyimide resin-fine particle composite film where the individual fine particles are in contact with each other. Adjacent holes formed by this.

FIG. 2 is an SEM image obtained by observing the surface of the polyimide-based resin porous membrane of the present embodiment with a scanning electron microscope (acceleration voltage 5.0 kV, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). ..
The polyimide-based resin porous film 10 of the present embodiment has a porous structure in which adjacent spherical cells 1 communicate with each other.
In the polyimide-based resin porous film 10, a spherical cell 1 and a communication hole in which adjacent spherical cells 1 communicate with each other are formed, and the degree of porosity is increased. Further, in the polyimide-based resin porous membrane 10, the spherical cell 1 or the communication hole opens on the surface of the polyimide-based resin porous membrane 10, and the communication hole opened on one surface inside the polyimide-based resin porous membrane 10. A flow path is formed which allows the fluid to pass through the inside of the polyimide-based resin porous membrane 10 by communicating with the other (back side) surface. Then, according to the polyimide-based resin porous membrane 10, the object to be filtered (resist composition) flows through the flow path, and the foreign matter contained in the object to be filtered (resist composition) is not filtered by separation and / or adsorption. Is removed from the object to be filtered.

The polyimide-based resin porous membrane contains a resin and may be substantially composed of only a resin, and is preferably 95% by mass or more, more preferably 98% by mass or more of the entire porous membrane. More preferably, 99% by mass or more is a resin.
The polyimide-based resin porous film contains at least one of polyimide or polyamide-imide as a resin, preferably at least polyimide, and may contain only polyimide or only polyamide-imide as a resin.

The polyimide-based resin may have at least one functional group selected from the group consisting of a carboxy group, a salt-type carboxy group, and an -NH- bond.
The polyimide-based resin preferably has the functional group other than the terminal of the main chain. Preferred examples of the functional group having the functional group other than the terminal of the main chain include polyamic acid (polyamic acid).

As used herein, the term "salt-type carboxy group" means a group in which a hydrogen atom in a carboxy group is replaced with a cation component. The "cation component" may be a cation itself in a completely ionized state, or may be a cation component in a state of being ion-bonded with -COO- ^and having virtually no charge. However, it may be a cation component having a partial charge, which is an intermediate state between the two.
When the "cation component" is an M ion component composed of an n-valent metal M, the cation itself is represented as M ^{n +} , and the cation component is "M _{1 / n" in "-COOM 1 / n} ". It is an element represented by.

Examples of the "cation component" include cations when a compound mentioned as a compound contained in the etching solution described later is ion-dissociated. Typical examples include an ionic component or an organic alkaline ionic component. For example, when the alkali metal ion component is a sodium ion component, the cation itself is a sodium ion (Na ⁺ ), and the cation component is an element represented by "Na" in "-COONa". The partially charged cation component is Na ^{δ +} .
The cation component is not particularly limited, and examples thereof include an inorganic component; an organic component such as NH ₄₊ and ^N ₍ CH ₃ ) ⁴⁺ . Examples of the inorganic component include alkali metals such as Li, Na and K; and metal elements such as alkaline earth metals such as Mg and Ca. Examples of the organic component include an organic alkaline ion component. Examples of the organic alkali ion component include quaternary ammonium cations represented by NH ₄₊ , for example, NR ^{4+ (} all _four Rs represent organic groups and may be the same or different from each other). As the organic group of R, an alkyl group is preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. Examples of the quaternary ammonium cation include N (CH ₃ ) ₄ ⁺ and the like.

The state of the cation component in the salt-type carboxy group is not particularly limited, and usually depends on the environment in which the polyimide resin is present, for example, whether it is in an aqueous solution, an organic solvent, or dry. do. If the cation component is a sodium ion component, for example, in an aqueous solution, it may be dissociated into -COO- ^and Na ⁺ , and if it is in an organic solvent or dry,- It is highly possible that COONa is not dissociated.

The polyimide-based resin may have at least one functional group selected from the group consisting of a carboxy group, a salt-type carboxy group, and a -NH- bond, but when it has at least one of these, it is usually used. , Acarboxy group and / or a salt-type carboxy group, and a -NH- bond. The polyimide resin may have only a carboxy group, may have only a salt-type carboxy group, or may have a carboxy group and a salt-type carboxy group, as far as the carboxy group and / or the salt-type carboxy group is concerned. You may have both. The ratio of the carboxy group and the salt-type carboxy group of the polyimide resin may vary depending on the environment in which the polyimide resin is present, even if the polyimide resin is the same, and the concentration of the cation component can be adjusted. Is also affected.

In the case of polyimide, the total number of moles of the carboxy group and the salt-type carboxy group of the polyimide resin is usually equal to that of the -NH- bond.
In particular, in the method for producing a polyimide porous membrane described later, when a carboxy group and / or a salt-type carboxy group is formed from a part of the imide bond in the polyimide, an -NH- bond is also formed substantially at the same time. The total number of moles of the carboxy group formed and the salt-type carboxy group is equimolar to the -NH-bond formed.
In the case of the method for producing a polyamide-imide porous film, the total number of moles of the carboxy group and the salt-type carboxy group in the polyamide-imide is not necessarily the same as that of the -NH- bond, and the etching (opening of the imide bond) described later is performed. It depends on the conditions such as chemical etching in the process.

The polyimide-based resin preferably has, for example, at least one structural unit selected from the group consisting of the structural units represented by the following general formulas (1) to (4).
In the case of polyimide, it is preferable to have at least one structural unit selected from the group consisting of the structural unit represented by the following general formula (1) and the structural unit represented by the following general formula (2).
In the case of polyamide-imide, those having at least one structural unit selected from the group consisting of the structural unit represented by the following general formula (3) and the structural unit represented by the following general formula (4) are preferable.

In the above formulas ( ¹ ) to ( ³ ), X1 to X4 may be the same or different from each other, and are hydrogen atoms or cation components.
R _Ar is an aryl group, and is a structural unit represented by the formula (5) constituting the polyamic acid described later or a structural unit represented by the formula (6) constituting the aromatic polyimide, respectively. Examples thereof include the same as the aryl group represented by _RA to which the carbonyl group is bonded.
Y ¹ to Y ⁴ are each independently a divalent residue excluding the amino group of the diamine compound, and are a structural unit represented by the formula (5) constituting the polyamic acid described later, or an aromatic polyimide. Examples thereof include those similar to the arylene group represented by _R'Ar in which N is bonded in each of the constituent units represented by the constituent formula (6).

As the polyimide-based resin in the present invention, a part of the imide bond (-N [-C (= O)] ₂ ) possessed by a general polyimide or polyamide-imide is opened, and in the case of a polyimide, the above general formula is used. It may have each structural unit represented by (1) or the general formula (2), and in the case of polyamide-imide, it may have each structural unit represented by the above general formula (3).

The polyimide-based resin porous film is a polyimide-based resin having at least one functional group selected from the group consisting of a carboxy group, a salt-type carboxy group, and a -NH- bond by opening a part of an imide bond. It may contain.

The invariance rate when a part of the imide bond is opened is obtained by the following procedures (1) to (3).
Procedure (1): A polyimide-based resin porous film that does not undergo the etching (opening of the imide bond) step described later (however, when the varnish for producing the porous film contains polyamic acid, an unfired composite film is used. It is assumed that the imidization reaction is substantially completed in the firing step.) The area of the peak representing the imide bond measured by the Fourier transform infrared spectroscopic (FT-IR) apparatus is also FT-. The value (X01) represented by the value divided by the area of the peak representing benzene measured by the IR device is obtained.
Procedure (2): An etching (imide bond opening) step described later on a polyimide-based resin porous film obtained by using the same polymer (wanice) as the porous film for which the above value (X01) was obtained. For the polyimide-based resin porous film after the above, the area of the peak representing the imide bond measured by the Fourier transform infrared spectroscopy (FT-IR) apparatus is the peak area representing the benzene also measured by the FT-IR apparatus. The value (X02) represented by the value divided by the area is obtained.
Procedure (3): Calculate the particle rate from the following formula.
Particle constant (%) = (X02) ÷ (X01) × 100

The non-change rate in the polyimide-based resin porous membrane is preferably 60% or more, more preferably 70 to 99.5%, and even more preferably 80 to 99%.
In the case of a porous membrane containing a polyamide-imide, the invariance rate may be 100% because it contains a -NH- bond.

In the case of a polyimide porous film, the value obtained by dividing the area of the peak representing the imide bond measured by the FT-IR device by the area of the peak representing benzene also measured by the FT-IR device is defined as the "imidization rate". ..
The imidization ratio for the value (X02) obtained in the above procedure (2) is preferably 1.2 or more, more preferably 1.2 to 2, and further preferably 1.3 to 1.6. It is particularly preferably 1.30 to 1.55, and most preferably 1.35 or more and less than 1.5. The imidization rate for the value (X01) obtained in the above procedure (1) is preferably 1.5 or more.
Such imidization ratio means that the larger the number, the larger the number of imide bonds, that is, the smaller the number of ring-opened imide bonds described above.

-Method for manufacturing a polyimide-based resin porous film The polyimide-based resin porous film is a step of forming a carboxy group and / or a salt-type carboxy group from a part of imide bonds in polyimide and / or polyamide-imide (hereinafter, "etching"). It can be manufactured by a method including "process").
In the etching step, when a carboxy group and / or a salt-type carboxy group is formed from a part of the imide bond, an equimolar-NH- bond with these groups is theoretically formed at substantially the same time.

When the resin contained in the polyimide-based resin porous film is substantially composed of polyamide-imide, the porous film already has a -NH- bond even without performing an etching step, and foreign matter in the object to be filtered is obtained. Shows good adsorption power. In such a case, the etching step is not always necessary because it is not necessary to slow down the flow velocity of the object to be filtered, but it is preferable to provide the etching step from the viewpoint of more effectively achieving the object of the present invention.

As a method for producing a polyimide-based resin porous film, a molding film containing polyimide and / or polyamide-imide as a main component (hereinafter, may be abbreviated as "polyimide-based resin molding film") is prepared, and then an etching step is performed. It is preferable to do it.
The polyimide-based resin molding film to be subjected to the etching step may be porous or non-porous.
The form of the polyimide-based resin molded film is not particularly limited, but a thin shape such as a film is preferable and porous in that the degree of porosity in the obtained polyimide-based resin porous film can be increased. It is more preferable that the shape is thin such as a film.

As described above, the polyimide resin molding film may be non-porous when the etching step is performed, but in that case, it is preferable to make the polyimide-based resin molding film porous after the etching step.
As a method for making the polyimide resin molding film porous before or after the etching step, a composite film of polyimide and / or polyamide-imide and fine particles (hereinafter referred to as "polyimide resin-fine particle composite film") is used. A method including a [removal of fine particles] step of removing the fine particles to make them porous is preferable.

Examples of the method for producing the polyimide-based resin porous film include the following production method (a) or production method (b).
Production method (a): A method of subjecting a composite film of polyimide and / or polyamide-imide and fine particles to an etching step before the [removal of fine particles] step.
Production method (b): A method of performing an etching step on the polyimide resin molded film made porous by the step after the [removal of fine particles] step. Among these, the degree of porosity in the obtained polyimide resin porous film. The latter manufacturing method (b) is preferable from the viewpoint that the above can be further enhanced.

An example of a method for manufacturing a polyimide-based resin porous membrane will be described below.

[Preparation of varnish]
A fine particle dispersion in which fine particles are dispersed in an organic solvent in advance is mixed with polyamic acid, polyimide or polyamide-imide in an arbitrary ratio, or tetracarboxylic acid dianhydride and diamine are polymerized in the fine particle dispersion. A varnish is prepared by using a polyamic acid or by further imidizing the polyamic acid to form a polyimide.
The viscosity of the varnish is preferably 300 to 2000 cP (0.3 to 2 Pa · s), more preferably 400 to 1800 cP (0.4 to 1.8 Pa · s). If the viscosity of the varnish is within the above range, the film can be formed more uniformly.
The viscosity of the varnish can be measured by an E-type rotational viscometer under a temperature condition of 25 ° C.

When the varnish is fired (dried if firing is optional) to form a polyimide resin-fine particle composite film, the ratio of fine particles / polyimide resin is preferably 1 to 4 (mass ratio), more preferably. The resin fine particles and polyamic acid, polyimide or polyamide-imide are mixed so as to have a mass ratio of 1.1 to 3.5 (mass ratio).
Further, when the polyimide resin-fine particle composite film is formed, the volume ratio of the fine particle / polyimide resin is preferably 1.1 to 5, more preferably 1.1 to 4.5. The fine particles are mixed with polyamic acid or polyimide or polyamide-imide.
When the mass ratio or volume ratio is equal to or more than the preferable lower limit value in the above range, pores having an appropriate density as a porous membrane can be easily obtained, and when the mass ratio or volume ratio is equal to or less than the preferable upper limit value in the above range, the viscosity is increased. Problems such as increase and cracks in the film are unlikely to occur, and stable film formation can be achieved.
In addition, in this specification, a volume ratio shows a value at 25 degreeC.

... Fine particles The fine particles can be used without particular limitation as long as they are insoluble in the organic solvent used for the varnish and can be selectively removed after the film formation.
Examples of the material of the fine particles include silica (silicon dioxide), titanium oxide, alumina (Al ₂ O ₃ ), and metal oxides such as calcium carbonate as inorganic materials. Examples of the organic material include high molecular weight olefin (polypropylene, polyethylene, etc.), polystyrene, acrylic resin (methyl methacrylate, isobutyl methacrylate, polymethylmethacrylate (PMMA), etc.), epoxy resin, cellulose, polyvinyl alcohol, polyvinyl butyral. , Polyester, polyether, polyethylene and other organic polymers.
Among these, silica such as colloidal silica is preferable as the inorganic material because minute pores having a curved surface on the inner surface are likely to be formed in the porous membrane. As the organic material, an acrylic resin such as PMMA is preferable.

The resin fine particles can be selected from, for example, ordinary linear polymers and known depolymerizable polymers without particular limitation depending on the intended purpose. Ordinary linear polymers are polymers in which the molecular chains of the polymer are randomly cleaved during thermal decomposition. A depolymerizable polymer is a polymer that decomposes into a monomer during thermal decomposition. Any polymer can be removed from the polyimide resin membrane by decomposing into a monomer, a low molecular weight substance, or CO ₂ when heated.

Among the depolymerizable polymers, from the viewpoint of handling at the time of pore formation, methyl methacrylate or isobutyl methacrylate having a low thermal decomposition temperature alone (polymethyl methacrylate or polyisobutyl methacrylate) or a copolymer polymer containing this as a main component. Is preferable.

The decomposition temperature of the resin fine particles is preferably 200 to 320 ° C, more preferably 230 to 260 ° C. When the decomposition temperature is 200 ° C. or higher, film formation can be performed even when a high boiling point solvent is used for the varnish, and the range of selection of firing conditions for the polyimide resin becomes wider. When the decomposition temperature is 320 ° C. or lower, only the resin fine particles can be easily eliminated without causing thermal damage to the polyimide resin.

The fine particles preferably have a high sphericity ratio because they tend to have a curved surface on the inner surface of the pores in the formed porous film. The particle size (average diameter) of the fine particles used is preferably, for example, 50 to 2000 nm, more preferably 200 to 1000 nm.
When the average diameter of the fine particles is within the above range, when the object to be filtered is passed through the polyimide-based resin porous membrane obtained by removing the fine particles, the object to be filtered is evenly contacted with the inner surface of the pores in the porous membrane. It is possible to efficiently adsorb foreign substances contained in the object to be filtered.

The particle size distribution index (d25 / d75) of the fine particles is preferably 1 to 6, more preferably 1.6 to 5, and even more preferably 2 to 4.
By setting the particle size distribution index to a preferable lower limit value or more in the above range, fine particles can be efficiently filled in the porous membrane, so that a flow path can be easily formed and the flow velocity is improved. In addition, holes of different sizes are likely to be formed, different convections occur, and the adsorption rate of foreign matter is further improved.
In addition, d25 and d75 are the values of the particle size of the cumulative frequency of the particle size distribution of 25% and 75%, respectively, and in the present specification, d25 is the one having the larger particle size.

Further, in the case of forming the unfired composite film as a two-layer in the [deposition of unfired composite film] described later, the fine particles (B1) used for the first varnish and the fine particles (B2) used for the second varnish are used. May use the same ones or different ones. In order to make the pores on the side in contact with the substrate more dense, it is preferable that the fine particles (B1) have a smaller or the same particle size distribution index than the fine particles (B2). Alternatively, the fine particles (B1) preferably have a smaller or the same sphericity ratio than the fine particles (B2). Further, the fine particles (B1) preferably have a smaller particle size (average diameter) than the fine particles (B2), and in particular, the fine particles (B1) have a particle size of 100 to 1000 nm (more preferably 100 to 600 nm) and the fine particles (B2). ) Is 500 to 2000 nm (more preferably 700 to 2000 nm), respectively. By using fine particles (B1) having a particle size smaller than that of the fine particles (B2), the opening ratio of the pores on the surface of the obtained polyimide-based resin porous membrane can be increased, the diameter can be made uniform, and the polyimide can be used. The strength of the porous film can be increased as compared with the case where the entire porous resin film is made of fine particles (B1) alone.

In the present invention, a dispersant may be further added to the varnish together with the fine particles for the purpose of uniformly dispersing the fine particles. By further adding the dispersant, the polyamic acid or polyimide or polyamide-imide can be mixed more uniformly with the fine particles, and the fine particles can be uniformly distributed in the unfired composite membrane. As a result, the front and back surfaces of the polyimide-based resin porous membrane are communicated with each other so as to provide a dense opening on the surface of the finally obtained polyimide-based resin porous membrane and improve the air permeability of the polyimide-based resin porous membrane. It is possible to efficiently form a communication hole for the communication.

The above-mentioned dispersant is not particularly limited, and known ones can be used. Examples of the dispersant include palm fatty acid salt, castor sulfate oil salt, lauryl sulfate salt, polyoxyalkylene allylphenyl ether sulfate salt, alkylbenzene sulfonic acid, alkylbenzene sulfonate, alkyldiphenyl ether disulfonate, and alkylnaphthalene. Anionic surfactants such as sulfonates, dialkyl sulfosuccinate salts, isopropyl phosphates, polyoxyethylene alkyl ether phosphate salts, polyoxyethylene allylphenyl ether phosphate salts; oleylamine acetate, laurylpyridinium chloride, cetylpyridinium chloride, lauryltrimethyl. Cationic surfactants such as ammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, didecyldimethylammonium chloride; palm alkyldimethylamine oxide, fatty acid amidepropyldimethylamine oxide, alkylpolyaminoethylglycine hydrochloride, amide betaine type activator , Alanine-type activator, amphoteric surfactant such as lauryliminodipropionic acid; polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene laurylamine, polyoxyethylene oleylamine, polyoxyethylene Polyoxyalkylene primary alkyl ether or polyoxyalkylene secondary alkyl ether nonionic surfactant, polyoxyethylene dilaurate, polyoxyethylene laurate, polyoxyethylenated Himasi oil, polyoxyethylene hydrogenated castor oil, sorbitan lauric acid ester, polyoxyethylene sorbitan lauric acid ester, fatty acid diethanolamide and other polyoxyalkylene-based nonionic surfactants; octyl stearate, trimethylolpropane tridecanoate, etc. Examples of the fatty acid alkyl ester; polyether polyols such as polyoxyalkylene butyl ether, polyoxyalkylene oleyl ether, and trimethylolpropanthris (polyoxyalkylene) ether. The above dispersants can be used alone or in admixture of two or more.

... Polyamic acid Examples of the polyamic acid that can be used in the present invention include those obtained by polymerizing an arbitrary tetracarboxylic acid dianhydride with a diamine.

... Tetracarboxylic acid dianhydride The tetracarboxylic acid dianhydride can be appropriately selected from the tetracarboxylic acid dianhydride that has been conventionally used as a raw material for synthesizing polyamic acid.
The tetracarboxylic dianhydride may be an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride.

Examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic acid dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, and bis (2,3-dicarboxyphenyl) methane. Dianhydride, Bis (3,4-dicarboxyphenyl) methane dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3', 4'-biphenyltetracarboxylic Acid dianhydride, 2,2,6,6-biphenyltetracarboxylic acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-bis) Dicarboxyphenyl) Propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropanedianhydride, 2,2-bis (3,4-dicarboxyphenyl) 2,3-Dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, bis (3,3) 4-Dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic acid dianhydride, 4,4- (p. -Phenylenedoxy) diphthalic acid dianhydride, 4,4- (m-phenylenedioxy) diphthalic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8 -Naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,3,4-benzenetetracarboxylic acid dianhydride, 3,4,9,10-perylene Tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, 9,9-bisfluorene phthalate, 3 , 3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride and the like.

Examples of the aliphatic tetracarboxylic dianhydride include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 1, Examples thereof include 2,4,5-cyclohexanetetracarboxylic dianhydride and 1,2,3,4-cyclohexanetetracarboxylic dianhydride.

Among the above, aromatic tetracarboxylic dianhydride is preferable from the viewpoint of heat resistance of the obtained polyimide resin. Among them, 3,3', 4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride are preferable from the viewpoint of price, availability and the like.
The tetracarboxylic dianhydride may be used alone or in admixture of two or more.

... Diamine Diamine can be appropriately selected from diamines conventionally used as a synthetic raw material for polyamic acid. This diamine may be an aromatic diamine or an aliphatic diamine, but an aromatic diamine is preferable from the viewpoint of heat resistance of the obtained polyimide resin. Diamines can be used alone or in admixture of two or more.

Examples of the aromatic diamine include a diamino compound having one phenyl group or about 2 to 10 phenyl groups bonded thereto. Specific examples of the aromatic diamine include phenylenediamine or its derivative, diaminobiphenyl compound or its derivative, diaminodiphenyl compound or its derivative, diaminotriphenyl compound or its derivative, diaminonaphthalene or its derivative, aminophenylaminoindan or its derivative. Examples thereof include derivatives, diaminotetraphenyl compounds or derivatives thereof, diaminohexaphenyl compounds or derivatives thereof, and cardo-type fluorangeamine derivatives.

As the phenylenediamine, m-phenylenediamine and p-phenylenediamine are preferable. Examples of the phenylenediamine derivative include diamines to which an alkyl group such as a methyl group and an ethyl group is bonded, for example, 2,4-diaminotoluene, 2,4-triphenylenediamine and the like.

A diaminobiphenyl compound is a compound in which two aminophenyl groups are bonded to each other. Examples of the diaminobiphenyl compound include 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl and the like.

A diaminodiphenyl compound is a compound in which two aminophenyl groups are bonded to each other via another group. Examples of other groups include ether bond, sulfonyl bond, thioether bond, alkylene group or derivative group thereof, imino bond, azo bond, phosphine oxide bond, amide bond, ureylene bond and the like. The alkylene group preferably has about 1 to 6 carbon atoms, and the derivative group thereof is one in which one or more hydrogen atoms of the alkylene group are substituted with a halogen atom or the like.

Examples of the diaminodiphenyl compound include 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4, 4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylketone, 3 , 4'-diaminodiphenylketone, 2,2-bis (p-aminophenyl) propane, 2,2'-bis (p-aminophenyl) hexafluoropropane, 4-methyl-2,4-bis (p-) Aminophenyl) -1-pentene, 4-methyl-2,4-bis (p-aminophenyl) -2-penten, iminodianiline, 4-methyl-2,4-bis (p-aminophenyl) pentane, Bis (p-aminophenyl) phosphinoxide, 4,4'-diaminoazobenzene, 4,4'-diaminodiphenylurea, 4,4'-diaminodiphenylamide, 1,4-bis (4-aminophenoxy) benzene, 1 , 3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl ] Sulphon, bis [4- (3-aminophenoxy) phenyl] sulphon, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl ] Hexafluoropropane and the like can be mentioned.

A diaminotriphenyl compound is a compound in which two aminophenyl groups and one phenylene group are bonded via other groups. Other groups include those similar to other groups in diaminodiphenyl compounds.
Examples of the diaminotriphenyl compound include 1,3-bis (m-aminophenoxy) benzene, 1,3-bis (p-aminophenoxy) benzene, and 1,4-bis (p-aminophenoxy) benzene.

Examples of diaminonaphthalene include 1,5-diaminonaphthalene and 2,6-diaminonaphthalene.

Examples of the aminophenyl aminoindane include 5- or 6-amino-1- (p-aminophenyl) -1,3,3-trimethylindane.

Examples of the diaminotetraphenyl compound include 4,4'-bis (p-aminophenoxy) biphenyl, 2,2'-bis [p- (p'-aminophenoxy) phenyl] propane, and 2,2'-bis [p-. Examples thereof include (p'-aminophenoxy) biphenyl] propane, 2,2'-bis [p- (m-aminophenoxy) phenyl] benzophenone and the like.

Examples of the cardo-type fluorene amine derivative include 9,9-bisaniline fluorene.

The aliphatic diamine preferably has, for example, about 2 to 15 carbon atoms, and specific examples thereof include pentamethylenediamine, hexamethylenediamine, and heptamethylenediamine.

The diamine may be a compound in which a hydrogen atom is substituted with at least one substituent selected from the group consisting of a halogen atom, a methyl group, a methoxy group, a cyano group and a phenyl group.

Among the above, as the diamine, phenylenediamine, a phenylenediamine derivative, and a diaminodiphenyl compound are preferable. Among them, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, and 4,4'-diaminodiphenyl ether are particularly preferable from the viewpoint of price, availability, and the like.

The method for producing the polyamic acid is not particularly limited, and a known method such as a method of reacting an arbitrary tetracarboxylic dianhydride with a diamine in an organic solvent is used.
The reaction of the tetracarboxylic dianhydride with the diamine is usually carried out in an organic solvent. The organic solvent used here is not particularly limited as long as it can dissolve tetracarboxylic dianhydride and diamine, respectively, and does not react with tetracarboxylic dianhydride and diamine. The organic solvent can be used alone or in combination of two or more.

Examples of the organic solvent used for the reaction between the tetracarboxylic acid dianhydride and the diamine include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, and the like. Nitrogen-containing polar solvents such as N, N-diethylformamide, N-methylcaprolactam, N, N, N', N'-tetramethylurea; β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valero Lactone-based polar solvents such as lactone, γ-caprolactone and ε-caprolactone; dimethylsulfoxide; acetonitrile; fatty acid esters such as ethyl lactate and butyl lactate; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, tetrahydrofuran, methylcell solve acetate, ethylcell Ethers such as solve acetate; phenolic solvents such as cresols can be mentioned.

Among these, as the organic solvent here, it is preferable to use a nitrogen-containing polar solvent from the viewpoint of the solubility of the polyamic acid produced.
Further, from the viewpoint of film forming property and the like, it is preferable to use a mixed solvent containing a lactone-based polar solvent. In this case, the content of the lactone-based polar solvent is preferably 1 to 20% by mass, more preferably 5 to 15% by mass, based on the total amount of the organic solvent (100% by mass).
As the organic solvent here, it is preferable to use one or more selected from the group consisting of a nitrogen-containing polar solvent and a lactone-based polar solvent, and a mixed solvent of a nitrogen-containing polar solvent and a lactone-based polar solvent may be used. More preferred.
The amount of the organic solvent used is not particularly limited, but is preferably such that the content of the polyamic acid produced in the reaction solution after the reaction is 5 to 50% by mass.

The amount of each of the tetracarboxylic acid dianhydride and the diamine used is not particularly limited, but it is preferable to use 0.50 to 1.50 mol of the diamine with respect to 1 mol of the tetracarboxylic acid dianhydride, and 0.60 to 0.60 to 1.50 mol. It is more preferable to use 1.30 mol, and it is particularly preferable to use 0.70 to 1.20 mol.

The reaction (polymerization) temperature is generally −10 to 120 ° C., preferably 5 to 30 ° C.
The reaction (polymerization) time varies depending on the raw material composition used, but is usually 3 to 24 (hours).
Further, the intrinsic viscosity of the polyamic acid solution obtained under such conditions is preferably in the range of 1000 to 100,000 cP (centipores) (1 to 100 Pa · s), more preferably 5000 to 70,000 cP (5 to 70 Pa · s). be.
The intrinsic viscosity of the polyamic acid solution can be measured by an E-type rotational viscometer under a temperature condition of 25 ° C.

... Polyimide As the polyimide that can be used in the present invention, any known polyimide can be used as long as it can be dissolved in the organic solvent used for the varnish, regardless of its structure and molecular weight.
The polyimide may have a condensable functional group such as a carboxy group in the side chain, or a functional group that promotes a crosslinking reaction or the like during firing.

Since the polyimide is soluble in the organic solvent used for the varnish, it is effective to use a monomer for introducing a flexible bent structure into the main chain.
Examples of this monomer include aliphatic diamines such as ethirediamine, hexamethylenediamine, 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, and 4,4'-diaminodicyclohexylmethane; 2-methyl-1,4-phenylene. Aromatic diamines such as diamine, o-tridine, m-tridine, 3,3'-dimethoxybenzidine, 4,4'-diaminobenzanilide; polyoxyalkylenes such as polyoxyethylenediamine, polyoxypropylenediamine and polyoxybutylenediamine. Diamine; Polysiloxane Diamine; 2,3,3', 4'-oxydiphthalic acid anhydride, 3,4,3', 4'-oxydiphthalic acid anhydride, 2,2-bis (4-hydroxyphenyl) propandibenzoate -3,3', 4,4'-tetracarboxylic acid dianhydride and the like can be mentioned.

It is also effective to use a monomer having a functional group that improves the solubility in such an organic solvent. Examples of the monomer having such a functional group include fluorinated diamines such as 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl and 2-trifluoromethyl-1,4-phenylenediamine. Can be mentioned.
Further, in addition to the monomer having such a functional group, the monomer exemplified in the above description of the polyamic acid can be used in combination as long as the solubility is not impaired.

The method for producing polyimide is not particularly limited, and examples thereof include known methods such as a method of chemically imidizing or heat imidizing a polyamic acid and dissolving it in an organic solvent.

Examples of the polyimide that can be used in the present invention include aliphatic polyimides (all-aliphatic polyimides) and aromatic polyimides, and among them, aromatic polyimides are preferable.
The aromatic polyimide is obtained by thermally or chemically ring-closing a polyamic acid having a structural unit represented by the following general formula (5), or a configuration represented by the following general formula (6). It may be obtained by dissolving a polyimide having a unit in a solvent.
In the formula, R _Ar represents an aryl group and _R'Ar represents an arylene group.

In the above formula, R _Ar is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 π electrons, and may be a monocyclic type or a polycyclic type. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Can be mentioned. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom, a nitrogen atom and the like. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Among them, an aromatic hydrocarbon ring is preferable, benzene and naphthalene are more preferable, and benzene is particularly preferable.
In the above formula, _{R'Ar includes a group obtained by removing two hydrogen atoms from the aromatic ring in the above R Ar .} Among them, a group in which two hydrogen atoms are removed from an aromatic hydrocarbon ring is preferable, a group in which two hydrogen atoms are removed from benzene or naphthalene is more preferable, and a phenylene group in which two hydrogen atoms are removed from benzene is particularly preferable.
The aryl group in R _Ar and the arylene group in _R'Ar may each have a substituent.

... Polyamide-imide As the polyamide-imide that can be used in the present invention, any known polyamide-imide can be used as long as it can be dissolved in the organic solvent used for the varnish, regardless of its structure and molecular weight.
The polyamide-imide may have a condensable functional group such as a carboxy group in the side chain, or a functional group that promotes a crosslinking reaction or the like during firing.

The polyamide-imide can be obtained by imidizing a precursor polymer obtained by reacting any trimellitic anhydride with diisocyanate or a reactive derivative of any trimellitic anhydride with diamine. Anything can be used without particular limitation.

Examples of the above-mentioned reactive derivative of trimellitic anhydride include trimellitic acid halides such as trimellitic acid chloride, and trimellitic acid esters anhydrous.

Examples of the above-mentioned arbitrary diisocyanate include metaphenylene diisocyanate, p-phenylenedi isocyanate, o-trizine diisocyanate, p-phenylenedi isocyanate, m-phenylenedi isocyanate, 4,4'-oxybis (phenylisocyanate), and 4,4'-diisocyanate. Diphenylmethane, bis [4- (4-isocyanatephenoxy) phenyl] sulfone, 2,2'-bis [4- (4-isocyanatephenoxy) phenyl] propane, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate , 4,4'-Diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 3,3'-diethyldiphenyl-4,4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4' -Dicyclohexylmethane diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, naphthalene diisocyanate and the like can be mentioned.

Examples of the above-mentioned optional diamine include the same diamines exemplified in the above-mentioned description of the polyamic acid.

... Organic solvent The organic solvent that can be used to prepare the varnish is not particularly limited as long as it can dissolve polyamic acid and / or polyimide resin and does not dissolve fine particles, and is tetracarboxylic acid dianhydride. Examples thereof include those similar to the organic solvent used for the reaction between the substance and the diamine.
The organic solvent can be used alone or in combination of two or more.

The content of the organic solvent in the varnish is preferably 50 to 95% by mass, more preferably 60 to 85% by mass. The solid content concentration in the varnish is preferably 5 to 50% by mass, more preferably 15 to 40% by mass.

Further, in the case of forming the unfired composite film as a two-layer in the [deposition of unfired composite film] described later, the volume of the polyamic acid or polyimide or polyamide-imide (A1) and the fine particles (B1) in the first varnish. The ratio is preferably 19:81 to 45:55. When the volume ratio of the fine particles (B1) is 100 as a whole, if it is 55 or more, the particles are uniformly dispersed, and if it is 81 or less, the particles are easily dispersed without agglomeration. This makes it possible to uniformly form holes on the side surface side of the base material of the polyimide resin molding film.
Further, it is preferable that the volume ratio of the polyamic acid or polyimide or polyamide-imide (A2) to the fine particles (B2) in the second varnish is 20:80 to 50:50. When the volume ratio of the fine particles (B2) is 100 or more, if the volume ratio is 50 or more, the particles are likely to be uniformly dispersed, and if the volume ratio is 80 or less, the particles do not aggregate with each other. Cracks and the like are less likely to occur on the surface. This facilitates the formation of a polyimide resin porous film having good mechanical properties such as stress and elongation at break.

Regarding the above volume ratio, it is preferable that the second varnish has a lower fine particle content ratio than the first varnish. By satisfying the above conditions, the strength and flexibility of the unfired composite film, the polyimide resin-fine particle composite film, and the polyimide resin porous film even if the fine particles are highly filled in the polyamic acid or polyimide or polyamide-imide. Sex is ensured. Further, by providing a layer having a low fine particle content ratio, the manufacturing cost can be reduced.

When preparing varnish, in addition to the above-mentioned components, antistatic agent, flame retardant, chemical imidizing agent, condensing agent for the purpose of antistatic, flame retardant imparting, low temperature firing, mold release, coatability, etc. , Known components such as a mold release agent and a surface conditioner can be blended as needed.

[Film formation of unfired composite film]
To form an unfired composite film containing polyamic acid or polyimide or polyamide-imide and fine particles, for example, the varnish is applied onto a substrate and the temperature is 0 to 120 ° C. (preferably 0) under normal pressure or vacuum. It is dried under the conditions of (~ 100 ° C.), more preferably 60 to 95 ° C. (more preferably 65 to 90 ° C.) under normal pressure. The coating film thickness is, for example, preferably 1 to 500 μm, more preferably 5 to 50 μm.

A release layer may be provided on the base material as needed. Further, in the film formation of the unfired composite film, a dipping step, a drying step, and a pressing step in a solvent containing water may be provided as arbitrary steps before the [firing of the unfired composite film] described later.

The release layer can be produced by applying a release agent on a substrate and drying or baking. As the release agent used here, known release agents such as an alkyl phosphate ammonium salt-based release agent, a fluorine-based release agent, and a silicone-based release agent can be used without particular limitation.
When the unfired composite film after drying is peeled from the substrate, a small amount of the release agent remains on the peeled surface of the unfired composite film. Since the remaining mold release agent may affect the wettability of the surface of the polyimide resin porous film and the mixing of impurities, it is preferable to remove it.
Therefore, it is preferable to wash the unfired composite film peeled off from the substrate with an organic solvent or the like. Examples of the cleaning method include known methods such as a method of immersing the unfired composite film in the cleaning liquid and then taking it out, and a method of shower cleaning.
In order to dry the unfired composite film after washing, for example, the unfired composite film after washing is air-dried at room temperature or heated to an appropriate set temperature in a constant temperature bath. At that time, for example, a method of fixing the end portion of the unfired composite film to a SUS mold or the like to prevent deformation can be adopted.

On the other hand, when the base material is used as it is without providing the release layer in the film formation of the unfired composite film, the step of forming the release layer and the step of cleaning the unfired composite film can be omitted.

When the unfired composite film is formed into a two-layer film, first, the first varnish is applied as it is on a substrate such as a glass substrate, and the temperature is 0 to 120 ° C. (preferably 0) under normal pressure or vacuum. It is dried under the conditions of (~ 90 ° C.), more preferably 10 to 100 ° C. (more preferably 10 to 90 ° C.) at normal pressure to form a first unfired composite film having a film thickness of 1 to 5 μm.
Subsequently, the second varnish is applied onto the first unfired composite film, and similarly, 0 to 80 ° C. (preferably 0 to 50 ° C.), more preferably 10 to 80 ° C. (further) at normal pressure. By drying under the condition of (preferably 10 to 30 ° C.) to form a second unfired composite film having a thickness of 5 to 50 μm, a two-layer unfired composite film can be formed.

[Baking of unbaked composite film]
After the above [film formation of unfired composite film], the unfired composite film is heat-treated (baked) to form a composite film (polyimide-based resin-fine particle composite film) composed of a polyimide-based resin and fine particles. It is formed.
When the varnish contains polyamic acid, it is preferable to complete the imidization by [calcination of the uncalcined composite membrane] in this step.

The temperature of the heat treatment (baking temperature) varies depending on the structure of the polyamic acid or polyimide or polyamide-imide contained in the unfired composite film and the presence or absence of a condensing agent, but is preferably 120 to 400 ° C., more preferably 150 to 375. ℃.

In order to perform firing, it is not always necessary to clearly separate the operation from the drying in the previous process. For example, in the case of firing at 375 ° C, a method of raising the temperature from room temperature to 375 ° C in 3 hours and then holding the temperature at 375 ° C for 20 minutes, or a method of gradually raising the temperature from room temperature to 375 ° C in increments of 50 ° C ( It is also possible to use a stepwise drying-heat imidization method, such as holding for 20 minutes at each step) and finally holding at 375 ° C. for 20 minutes. At that time, a method may be adopted in which the end portion of the unfired composite film is fixed to a SUS mold or the like to prevent deformation.

The thickness of the polyimide resin-fine particle composite film after heat treatment (firing) is, for example, preferably 1 μm or more, more preferably 5 to 500 μm, and even more preferably 8 to 100 μm.
The thickness of the polyimide resin-fine particle composite film can be determined by measuring the thicknesses of a plurality of points using a micrometer and averaging them.

This step is an arbitrary step. In particular, when polyimide or polyamide-imide is used for the varnish, this step may not be performed.

[Removal of fine particles]
After the above [firing of the unfired composite film], the polyimide-based resin porous film is produced by removing the fine particles from the non-polyimide-based resin-fine particle composite film.
For example, when silica is used as the fine particles, the silica is dissolved and removed by contacting the polyimide resin-fine particle composite film with low-concentration hydrogen fluoride (HF) water, and a porous film is obtained. When the fine particles are resin fine particles, the resin fine particles are decomposed and removed by heating to a temperature equal to or higher than the thermal decomposition temperature of the resin fine particles and lower than the thermal decomposition temperature of the polyimide-based resin to obtain a porous film.

[Etching (ring opening of imide bond)]
The etching step can be performed by a chemical etching method, a physical removal method, or a method in which these are combined.

-Chemical etching method A conventionally known method can be used for the chemical etching method.
The chemical etching method is not particularly limited, and examples thereof include treatment with an etching solution such as an inorganic alkaline solution or an organic alkaline solution. Above all, treatment with an inorganic alkaline solution is preferable.
Examples of the inorganic alkaline solution include a hydrazine solution containing hydrazine hydrate and ethylenediamine; a solution of an alkali metal hydroxide such as potassium hydroxide, sodium hydroxide, sodium carbonate, sodium silicate, and sodium metasilicate; an ammonia solution; Examples thereof include an etching solution containing alkali hydroxide, hydrazine and 1,3-dimethyl-2-imidazolidinone as main components.
Examples of the organic alkaline solution include primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; dimethylethanolamine. , Alcohol amines such as triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; alkaline etching solutions such as cyclic amines such as pyrrole and pihelidine. The alkali concentration in the etching solution is, for example, 0.01 to 20% by mass.

Pure water and alcohols can be appropriately selected as the solvent for each of the above-mentioned etching solutions, and those to which an appropriate amount of a surfactant is added can also be used.

-Physical removal method As the physical removal method, for example, a dry etching method using plasma (oxygen, argon, etc.), corona discharge, or the like can be used.

The above-mentioned chemical etching method or physical removal method can be applied before the above-mentioned [removal of fine particles] or after the above-mentioned [removal of fine particles].
Above all, it is preferable to apply after the above [removal of fine particles] because the communication holes inside the polyimide resin porous film are more easily formed and the removability of foreign substances is enhanced.

When the chemical etching method is performed in the etching step, a step of cleaning the polyimide-based resin porous film may be provided after this step in order to remove excess etching solution.
The cleaning after the chemical etching may be performed by washing alone with water, but it is preferable to combine pickling and washing with water.

Further, after the etching step, the polyimide-based resin porous film may be heat-treated (refired) in order to improve the wettability of the surface of the polyimide-based resin porous film with an organic solvent and remove residual organic substances. good. This heating condition is the same as the condition in the above-mentioned [Baking of unfired composite film].

For example, in the polyimide-based resin porous membrane manufactured by the above-mentioned manufacturing method, a spherical cell 1 and a communication hole in which adjacent spherical cells 1 are communicated with each other are formed in the same manner as in the embodiment shown in FIG. Preferably, the communication hole that opens to one of the outer surfaces communicates with the inside of the polyimide-based resin porous membrane 10 and opens to the other (back side) outer surface, so that the fluid forms the polyimide-based resin porous membrane 10. It has a communication hole so as to secure a flow path through which it can pass.

The garley air permeability of the polyimide-based resin porous membrane is preferably 30 seconds or more, for example, from the viewpoint of efficiently removing foreign substances while maintaining the flow velocity of the object to be filtered passing through the porous membrane to some extent. The garley air permeability of the polyimide resin porous membrane is more preferably 30 to 1000 seconds, further preferably 30 to 600 seconds, particularly preferably 30 to 500 seconds, and most preferably 30 to 300 seconds. Is. When the garley air permeability is not more than the preferable upper limit value in the above range, the degree of porosity (abundance ratio of communication holes, etc.) is sufficiently high, so that the effect of removing foreign substances can be more easily obtained.
The Garley air permeability of the polyimide resin porous membrane can be measured according to JIS P 8117.

The polyimide-based resin porous membrane preferably includes communication pores having a pore diameter of 1 to 200 nm, more preferably 3 to 180 nm, still more preferably 5 to 150 nm, and particularly preferably 10 to 130 nm.
The hole diameter of the communication hole means the diameter of the communication hole. Since one communication hole is usually formed from two adjacent particles by the above-mentioned manufacturing method, the diameter is defined as, for example, the direction in which the two holes constituting the communication hole are adjacent to each other in the longitudinal direction. , The case where the diameter is the direction perpendicular to the longitudinal direction is included.
When the above-mentioned etching (ring-opening of imide bond) step is not provided, the pore diameter of the communication hole tends to be small.

The average pore size of the polyimide resin porous membrane is preferably 100 to 2000 nm, more preferably 200 to 1000 nm, and even more preferably 300 to 900 nm.
The average pore size of the polyimide-based resin porous membrane is determined by the bubble point method using a palm poromometer (for example, manufactured by Porous Materials Co., Ltd.) for the porous film subjected to the above-mentioned chemical etching (for example, polyimide porous membrane). It is a value obtained by measuring the diameter of the communication hole based on. For a porous film that is not chemically etched (for example, a polyamide-imide porous film), the average particle size of the fine particles used to produce the porous film is defined as the average pore size.

As described above, the polyimide-based resin porous film in the present invention is preferably a porous film containing pores having an average pore size of several hundred nanometers. Therefore, for example, even minute substances in the nanometer unit can be adsorbed or captured in the pores and / or the communication pores in the porous membrane.

As for the pore diameter of the communication hole, when the distribution of the pore diameter of each hole that imparts porosity to the polyimide resin porous film is broad, the pore diameter of the communication hole formed between the adjacent holes tends to be smaller. be.
From the viewpoint of reducing the pore diameter of the communication holes, the porosity of the polyimide resin porous membrane is, for example, preferably 50% by mass or more, more preferably 60 to 90% by mass, still more preferably 60 to 80% by mass, and particularly preferably. Is about 70% by mass. When the porosity is at least a preferable lower limit value in the above range, the effect of removing foreign matter can be more easily obtained. When it is not more than the preferable upper limit value in the above range, the strength of the porous membrane is further increased.
The porosity of the polyimide-based resin porous film is obtained by calculating the ratio of the mass of the fine particles to the total mass of the resin and the like used in producing the porous film and the fine particles.

The polyimide resin porous film is excellent in mechanical properties such as stress and elongation at break.
The stress of the polyimide-based resin porous membrane included in the filtration filter is, for example, preferably 10 MPa or more, more preferably 15 MPa or more, still more preferably 15 to 50 MPa.
The stress of the polyimide-based resin porous membrane is a value measured by preparing a sample having a size of 4 mm × 30 mm and using a tester under measurement conditions of 5 mm / min.

The breaking elongation of the polyimide-based resin porous film is, for example, preferably 10% GL or more, and more preferably 15% GL or more. The upper limit of the elongation at break is, for example, preferably 50% GL or less, more preferably 45% GL or less, still more preferably 40% GL or less. Decreasing the porosity of the polyimide resin porous film tends to increase the elongation at break.
The breaking elongation of the polyimide-based resin porous film is a value measured by preparing a sample having a size of 4 mm × 30 mm and using a testing machine under measurement conditions of 5 mm / min.

The thermal decomposition temperature of the polyimide resin porous membrane is preferably 200 ° C. or higher, more preferably 320 ° C. or higher, still more preferably 350 ° C. or higher.
The thermal decomposition temperature of the polyimide resin porous film can be measured by raising the temperature to 1000 ° C. at a heating rate of 10 ° C./min in an air atmosphere.

In the polyimide-based resin porous membrane, the object to be filtered flows through the communication holes and passes through the inside of the porous membrane.
The shape of the pores and the communication holes is not particularly limited as the polyimide-based resin porous membrane, but a porous membrane containing pores having a curved surface on the inner surface is preferable, and many of the pores (preferably pores) in the porous membrane are preferable. It is more preferable that the entire inner surface) is formed of a curved surface.
Here, "having a curved surface on the inner surface" with respect to the hole means that the hole providing porosity has a curved surface on at least a part of the inner surface.
The polyimide-based resin porous film has an internal flow path in which communication holes formed by holes having curved surfaces on the inner surface are continuous, so that the surface area of the inner surface of the holes is increased. This not only allows the object to be filtered to pass through the inside of the porous membrane, but also increases the frequency of contact with the inner surface of the pores when passing while in contact with the curved surface of each pore, and foreign matter present in the object to be filtered. Is adsorbed by the inner surface of the hole, and foreign matter is easily removed from the object to be filtered.

In the present invention, a hole in which almost the entire inner surface of the hole in the polyimide resin porous film is a curved surface may be referred to as a "substantially spherical hole" or a "spherical cell". In the substantially spherical hole (spherical cell), the inner surface of the hole forms a substantially spherical space. The spherical cell is easily formed when the fine particles used in the above-mentioned method for producing a polyimide resin porous film are substantially spherical.
The "substantially spherical" is a concept including a true sphere, but is not necessarily limited to a true sphere, and is a concept including a substantially spherical one. "Substantially spherical" means that the sphericity defined by the major axis / minor axis, which is expressed by dividing the major axis of the particle by the minor axis, is within 1 ± 0.3. do. The spherical cell of the polyimide-based resin porous membrane in the present invention has such a sphericity of preferably 1 ± 0.1 or less, more preferably 1 ± 0.05 or less.

Since the pores in the polyimide-based resin porous membrane have a curved surface on the inner surface, when the object to be filtered is passed through the porous membrane, the object to be filtered sufficiently spreads inside the pores in the porous membrane, and the inner surface of the pores is sufficiently spread. And in some cases, there may be convection along the inner surface of the hole. As a result, foreign matter existing in the object to be filtered is more easily adsorbed on the inner surface of the pores in the polyimide resin porous film.
As the polyimide-based resin porous membrane, a porous membrane having a porous structure in which adjacent spherical cells communicate with each other is particularly preferable.

The polyimide resin porous membrane having spherical cells preferably has a structure in which spherical cells having an average spherical diameter of 50 to 2000 nm communicate with each other. The average spherical diameter of such spherical cells is more preferably 100 to 1000 nm, still more preferably 200 to 800 nm.
The average sphere diameter of such a spherical cell means an average value of the diameters of communication holes formed from two adjacent spherical cells. The average spherical diameter of the spherical cell can be obtained by the same method as the average pore diameter in the above-mentioned porous membrane.

Further, the flow path internally contained in the polyimide resin porous membrane having the spherical cells is selected from the group consisting of communication holes between the spherical cells and communication holes between the spherical cells and other cells1. It has more than a kind of communication hole. The diameter of the cells other than the above is appropriately determined in consideration of the size of the foreign matter removed from the object to be filtered and the like.
Further, the spherical cell may further have a recess on its inner surface. For example, a hole having a hole diameter smaller than that of the spherical cell may be formed in the concave portion, which opens on the inner surface of the spherical cell.

According to the filtration filter of the present embodiment described above, the object to be filtered is filtered by the filter provided with the polyimide-based resin porous membrane. As a result, foreign substances such as organic substances and metal impurities are removed from the object to be filtered more than ever. In particular, due to the use of the polyimide-based resin porous membrane, highly polar components and polymers that were difficult to remove in the past are sufficiently removed from the object to be filtered, and the highly polar polymer is particularly specific. Is removed.
The filtration filter of this embodiment is particularly suitable for filtering a chemical solution for lithography. According to such a filtration filter, impurities such as particles mixed in a chemical solution for lithography, such as a resist composition, a resin solution, a developing solution, a resist solvent, and a pre-wet solvent, are further removed.

Further, the filtration filter of this embodiment is replaced with a filter cartridge or the like for removing fine particle impurities which has been installed so far in a supply line of various chemicals or a POU (point of use) in a semiconductor manufacturing process, or with this. Can be used in combination. Therefore, various foreign substances can be efficiently removed from the object to be filtered (chemical solution for lithography) by the same apparatus and operation as in the conventional case, and a high-purity chemical solution for lithography can be prepared.

(Filtration method)
The filtration method of the second aspect of the present invention includes an operation of passing a chemical solution for lithography through the filtration filter of the first aspect. By such an operation, impurities such as particles mixed in the chemical solution and the like are removed.
Such an operation may be performed without a differential pressure (that is, the lithographic chemical solution may be passed through the filtration filter only by gravity), or may be performed with a differential pressure. Of these, the latter is preferable, and it is preferable to perform an operation of passing the lithographic chemical solution through the filtration filter by a differential pressure.

The "state in which the differential pressure is provided" means that there is a pressure difference between one side and the other side of the polyimide-based resin porous membrane provided in the filtration filter.
For example, pressurization (positive pressure) that applies pressure to one side of the polyimide resin porous film (the chemical solution supply side for lithography), and depressurization that makes one side (filtrate side) of the polyimide resin porous film negative pressure. (Negative pressure) and the like can be mentioned, and the former pressurization is preferable.

Pressurization applies pressure to the supply liquid side of the polyimide resin porous membrane in which the lithographic chemical solution (hereinafter sometimes referred to as "supply liquid") before passing through the polyimide resin porous membrane exists. be.
For example, it is preferable to apply pressure to the supply liquid side by using the flow pressure generated by the circulation or flow of the supply liquid, or by using the positive pressure of the gas.
The flow pressure can be generated, for example, by an active flow pressure addition method of a pump (liquid feed pump, circulation pump, etc.). Examples of the pump include a rotary pump, a diaphragm pump, a metering pump, a chemical pump, a plunger pump, a bellows pump, a gear pump, a vacuum pump, an air pump, a liquid pump and the like.
When the feed liquid is circulated or sent by the pump, the pump is usually arranged between the feed liquid tank (or the circulation tank) and the polyimide resin porous membrane.

The flow pressure may be, for example, the pressure applied to the polyimide-based resin porous film by the feed solution when the feed solution is passed through the polyimide-based resin porous film only by gravity. It is preferable that the pressure is applied by a specific flow pressure addition method.
The gas used for pressurization is preferably a gas that is inert or non-reactive with respect to the feed solution, and specific examples thereof include nitrogen and rare gases such as helium and argon.
As a method of applying pressure to the supply liquid side, it is preferable to use positive pressure of gas. At that time, the pressure on the filtrate side that has passed through the polyimide-based resin porous membrane may be atmospheric pressure without reducing the pressure.

Further, the pressurization may utilize both the flow pressure and the positive pressure of the gas. Further, the differential pressure may be a combination of pressurization and depressurization, for example, one that utilizes both flow pressure and depressurization, one that utilizes both positive pressure and depressurization of gas, or a flow fluid. It may utilize the positive pressure and the depressurization of the pressure and the gas. When the method of providing the differential pressure is combined, the combination of the fluid pressure and the positive pressure of the gas, and the combination of the fluid pressure and the depressurized pressure are preferable from the viewpoint of simplification of production and the like.
In the present invention, since the polyimide-based resin porous membrane is used, even one method of providing a differential pressure, for example, a positive pressure with a gas, is excellent in foreign matter removing performance.

The reduced pressure is to reduce the pressure on the filtrate side that has passed through the polyimide resin porous membrane. For example, the pressure may be reduced by a pump, but it is preferable to reduce the pressure to vacuum.

When the operation of passing the chemical solution for lithography through the filtration filter is performed with a differential pressure, the pressure difference is the film thickness, porosity or average pore size of the polyimide resin porous film used, or the desired degree of purification. , Flow rate, flow rate, concentration or viscosity of the feed solution, etc. are taken into consideration. For example, the pressure difference in the case of the so-called cross-flow method (flowing the supply liquid in parallel with the polyimide-based resin porous film) is preferably, for example, 3 MPa or less, and the so-called dead-end method (with respect to the polyimide-based resin porous film). The pressure difference in the case of flowing the feed liquid so as to intersect with each other is preferably 1 MPa or less, for example. The lower limit of each pressure difference is not particularly limited, and is preferably 10 Pa or more, for example.

The operation of passing the lithographic chemical solution through the filtration filter provided with the polyimide-based resin porous membrane described above can be performed while maintaining a high flow velocity of the lithographic chemical solution (supply liquid).
The flow rate in this case is not particularly limited, but for example, the flow rate of pure water when pressurized at room temperature (20 ° C.) at 0.08 MPa is preferably 1 mL / min or more, more preferably 3 mL / min or more. It is more preferably 5 mL / min or more, and particularly preferably 10 mL / min or more. The upper limit of the flow velocity is not particularly limited, and is, for example, 50 mL / min or less.
In the present invention, since the filtration filter provided with the polyimide-based resin porous membrane described above is used, filtration can be performed while maintaining a high flow velocity in this way, and the removal rate of foreign substances contained in the chemical solution for lithography is increased. Be done.

Further, the operation of passing the lithographic chemical solution through the filtration filter is preferably performed by setting the temperature of the lithographic chemical solution to 0 to 30 ° C., and more preferably set to 5 to 25 ° C.

As the filtration method of this embodiment, a circulation type filtration operation in which a lithographic chemical solution (supply solution) is constantly circulated and passed through a polyimide resin porous membrane can also be suitably applied.
Further, in the filtration method of this embodiment, the chemical solution for lithography may be passed through the filtration filter provided with the polyimide resin porous membrane a plurality of times, or at least a plurality of filtration filters including the polyimide resin porous membrane may be included. It may be passed through a filtration filter.

In the filtration method of this embodiment, before the feed liquid is passed through the polyimide resin porous membrane, the polyimide resin porous membrane is washed, the wettability with respect to the feed liquid is improved, or the polyimide resin porous membrane and the feed liquid are used. In order to adjust the surface energy with, a solution such as alcohol such as methanol, ethanol and isopropyl alcohol or ketone such as acetone and methyl ethyl ketone, water, a solvent contained in the feed solution or a mixture thereof is applied to the polyimide resin porous membrane. The liquid may be passed through contact.
In order to bring the above solution into contact with the polyimide-based resin porous membrane, the polyimide-based resin porous membrane may be impregnated or immersed in the above solution. By contacting the above solution with the polyimide-based resin porous membrane, for example, the solution can be infiltrated into the inner pores of the polyimide-based resin porous membrane. The contact between the solution and the polyimide resin porous membrane may be performed with the above-mentioned differential pressure provided, and in particular, when the solution is allowed to penetrate into the inner pores of the polyimide resin porous membrane, it is under pressure. It is preferable to do it in.

According to the filtration method of the present embodiment described above, impurities such as particles contained in the lithographic chemical solution are removed by the operation of passing the lithographic chemical solution through the filtration filter of the first aspect described above. As a result, foreign substances such as organic substances and metal impurities are removed from the object to be filtered (chemical solution for lithography) more than ever. In particular, since the filtration filter is provided with a polyimide resin porous membrane, highly polar components and polymers that were difficult to remove in the past are sufficiently removed from the object to be filtered (chemical solution for lithography). Highly polar polymers are specifically removed. Therefore, in the resist pattern formation, the occurrence of defects in the resist pattern after development is further suppressed.

Further, in the filtration method of this embodiment, the metal component as an impurity is sufficiently removed from the object to be filtered (chemical solution for lithography). Various base material components and organic solvents contained in the chemical solution for lithography contain metal components such as trace amounts of metal ion impurities. This metal component may be originally contained in the compounding component, but it may also be mixed from a chemical liquid transfer path such as a pipe of a manufacturing apparatus or a joint. In such a filtration method, for example, iron, nickel, zinc, chromium and the like that are easily mixed in the manufacturing process of the resist composition can be effectively removed.
For example, when the resist composition is filtered by the filtration method of this embodiment, a resist composition refined product having a metal component concentration of preferably less than 500 ppt (1 trillion percent), more preferably less than 100 ppt, and particularly preferably less than 10 ppt. Can be prepared.

(Manufacturing method of refined chemical products for lithography)
The method for producing a lithographic chemical solution refined product according to a third aspect of the present invention is a method having a step of filtering the lithographic chemical solution by the filtration method of the second aspect (hereinafter referred to as “filtration step”).
In such a filtration step, the chemical solution for lithography is filtered by the above <filtration filter>, that is, a filtration filter provided with a polyimide-based resin porous membrane.

The lithography chemical refined product produced by the method for producing a lithography chemical refined product according to the third aspect of the present invention is filtered by passing through a filtration filter provided with a polyimide-based resin porous membrane. Foreign substances such as organic substances and metal impurities have been removed. Such chemical refined products have very few fine particles of, for example, 30 nm or more.
The lithographic chemical solution refined product produced by the production method of this embodiment has further reduced impurities. For example, by using a resist composition refined product produced when the chemical solution for lithography is a resist composition, the generation of defects is further suppressed in the formation of a resist pattern, and defects such as scum and microbridge generation are reduced. It is possible to form a resist pattern having a good shape.
Further, even when the filtrate (refined product) obtained by filtering the chemical solution for lithography by the filtration filter of the first aspect is stored at 40 ° C. for 7 days, the generation of foreign substances is suppressed. That is, the lithographic chemical solution refined product is a high-purity product with further reduced impurities.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Manufacturing of filtration filters>
Using the raw materials shown below, a filtration filter having a polyimide porous membrane and a filtration filter having a polyamide-imide porous membrane were manufactured.

-Tetracarboxylic dianhydride: pyromellitic dianhydride.
-Diamine: 4,4'-diaminodiphenyl ether.
-Polyamide acid solution: Reaction product of pyromellitic acid dianhydride and 4,4'-diaminodiphenyl ether (solid content 21.9% by mass), solvent is N, N-dimethylacetamide.
Polyamideimide solution: Polyamideimide containing trimellitic acid anhydride and o-trizine diisocyanate as polymerization components (mass average molecular weight Mw about 30,000; solid content 14.0% by mass), solvent is N-methyl-2-pyrrolidone.
-Organic solvent (1): N, N-dimethylacetamide (DMAc).
-Organic solvent (2): γ-butyrolactone.
-Organic solvent (3): N-methyl-2-pyrrolidone (NMP).
-Dispersant: Polyoxyethylene secondary alkyl ether-based dispersant.
Fine particles: silica (1) (silica with a volume average particle size of 300 nm, particle size distribution index is about 1.5).

As the etching solution, the etching solution (1) shown below was used.
・ Etching liquid (1)
TMAH solution with a concentration of 1.0% by mass, the solvent is a mixed solvent of methanol: water = 4: 6 (mass ratio).

≪Manufacturing of polyimide porous membrane≫
[Preparation of silica dispersion (a)]
Silica (1) 23.1 parts by mass was added to a mixture of 23.1 parts by mass of the organic solvent (1) and 0.1 parts by mass of the dispersant, and the mixture was stirred to prepare a silica dispersion liquid (a).

[Preparation of varnish]
To 41.1 parts by mass of the polyamic acid solution, 42.0 parts by mass of the silica dispersion liquid (a) was added.
Next, a total of 66.9 parts by mass of the organic solvent (1) and the organic solvent (2) was used, and the solvent composition of the entire varnish was organic solvent (1): organic solvent (2) = 90:10 (mass ratio). The varnish was prepared by adding and stirring to prepare a varnish.
The volume ratio of polyamic acid to silica in the obtained varnish was 40:60 (mass ratio was 30:70).

[Film formation of unfired composite film]
The varnish obtained in the above [Preparation of varnish] was applied onto a PET film as a base material using an applicator. Then, it was prebaked at 90 ° C. for 5 minutes to form a coating film having a film thickness of 40 μm. Then, the formed coating film was immersed in water for 3 minutes. Then, the coating film was passed between the two rolls and pressed. At that time, the roll holding pressure was 3.0 kg / cm ² , the roll temperature was 80 ° C., and the moving speed of the unfired composite film was 0.5 m / min. After the pressing, the coating film was peeled off from the substrate to obtain an unfired composite film.

[Baking of unbaked composite film]
The unfired composite film obtained in the above [Film formation of unfired composite film] is imidized by heat treatment (baking) at a firing temperature of 400 ° C. for 15 minutes to obtain a polyimide-fine particle composite film. rice field.

[Removal of fine particles]
By immersing the polyimide-fine particle composite film obtained in the above [baking of unfired composite film] in a 10% HF solution for 10 minutes, the fine particles contained in the composite film were removed.
Then, it was washed with water and dried to obtain a polyimide porous membrane (PIm (1)).

The obtained polyimide porous film (PIm (1)) was observed with a scanning electron microscope (acceleration voltage 5.0 kV; trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). PIm (1) had a porous structure in which communication holes were formed in which adjacent spherical cells communicated with each other, as shown in FIG.

[Chemical etching]
By immersing the polyimide-fine particle composite membrane obtained in the above [baking of unfired composite membrane] in a 10% HF solution for 10 minutes, the fine particles contained in the composite membrane are removed to obtain a porous body. rice field. Then, it was washed with water and dried.
Then, according to the chemical etching conditions shown in the “CE” column in Table 1, the porous body after washing with water and drying was immersed in a predetermined etching solution for a predetermined time. The chemical etching conditions shown in Table 1 are as follows.
Condition 1: Immerse in the etching solution (1) for 2 minutes.
Then, the polyimide porous film (PIm (2)) was obtained by heat-treating (re-baking) at a re-baking temperature of 380 ° C. for 15 minutes each.

The obtained polyimide porous film (PIm (2)) was observed with a scanning electron microscope (acceleration voltage 5.0 kV; trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). PIm (2) had a porous structure in which communication holes were formed in which adjacent spherical cells communicated with each other, as shown in FIG.

≪Manufacturing of polyamide-imide porous membrane≫
[Preparation of silica dispersion (b)]
19.3 parts by mass of silica (1), 19.3 parts by mass of organic solvent (3), and 0.1 parts by mass of dispersant were mixed and stirred to prepare a silica dispersion liquid (b).

[Preparation of varnish]
To 53.6 parts by mass of the polyamide-imide solution, 35.0 parts by mass of the silica dispersion liquid (b) was added.
Next, the total amount of the organic solvent (1) and the organic solvent (3) was 33.7 parts by mass, and the solvent composition of the entire varnish was organic solvent (1): organic solvent (3) = 5: 95 (mass ratio). The varnish was prepared by adding and stirring to prepare a varnish.
The volume ratio of polyamide-imide to silica (2) in the obtained varnish was 40:60 (mass ratio was 30:70).

[Film formation of unfired composite film]
The varnish obtained in the above [Preparation of varnish] was applied onto a PET film as a base material using an applicator. Then, it was prebaked at 90 ° C. for 5 minutes to form a coating film having a film thickness of 40 μm. Then, the formed coating film was immersed in water for 3 minutes. Then, the coating film was passed between the two rolls and pressed. At that time, the roll holding pressure was 3.0 kg / cm ² , the roll temperature was 80 ° C., and the moving speed of the unfired composite film was 0.5 m / min. After the pressing, the coating film was peeled off from the substrate to obtain an unfired composite film.

[Baking of unbaked composite film]
The unfired composite film obtained in the above [Film formation of unfired composite film] was heat-treated (baked) at 280 ° C. for 15 minutes to obtain a polyamide-imide-fine particle composite film.

[Removal of fine particles]
The polyamide-imide-fine particle composite film obtained in the above [baking of unfired composite film] was immersed in a 10% HF solution for 10 minutes to remove fine particles contained in the composite film.
Then, it was washed with water and dried to obtain a polyamide-imide porous membrane (PAIm).

The obtained polyimide porous film (PAIm) was observed with a scanning electron microscope (acceleration voltage 5.0 kV; trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). The PAIm had a porous structure in which communication holes were formed in which adjacent spherical cells communicated with each other, as shown in FIG.

≪Manufacturing of filtration filters with other porous membranes≫
A filtration filter provided with a polyamide (nylon) porous membrane (PAm (d); pore size 20 nm, Pall, Dispo) was prepared.
A filtration filter provided with a polyamide (nylon) porous membrane (PAm (pou); Point of use, manufactured by Pall) was prepared.

FIG. 3 shows an SEM in which the surface of a polyamide (nylon) porous membrane (PAm (d)) is observed with a scanning electron microscope (acceleration voltage 5.0 kV; trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). It is a statue.
As shown in FIG. 3, the surface state of PAm (d) was different from the form shown in FIG. 2 (that is, a porous structure in which adjacent spherical cells communicate with each other).
The surface state of the polyamide (nylon) porous film (PAm (pou)) also has the form shown in FIG. 3 and the form shown in FIG. 2 (that is, the porous structure in which adjacent spherical cells communicate with each other). ) Was a different form.

A filtration filter equipped with a polyethylene porous membrane (PEm (pou); pore size of 3 nm, manufactured by Entegris, Point of use) was prepared.

FIG. 4 is an SEM image obtained by observing the surface of a polyethylene porous membrane (PEm (pou)) with a scanning electron microscope (acceleration voltage 5.0 kV; trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). ..
As shown in FIG. 4, the surface state of PEm (pou) was different from the form shown in FIG. 2 (that is, a porous structure in which adjacent spherical cells communicate with each other).

<Evaluation of filtration filter>
The filters provided with the polyimide porous membrane were evaluated as shown below.

[Imidization rate]
The imidization ratio of the polyimide porous membrane (PIm (2)) was determined.
PIm (2) represents an imide bond measured by a Fourier transform infrared spectroscopy (FT-IR) apparatus after heat treatment (refiring) for 15 minutes at a refiring temperature of 380 ° C. shown in Table 1. The value (area ratio) obtained by dividing the peak area by the peak area representing benzene also measured by the FT-IR apparatus was obtained, and this was used as the imidization ratio. The results are shown in Table 1.

[Garley air permeability]
A sample having a thickness of about 40 μm was cut out into a 5 cm square from the polyimide porous membrane (PIm (2)).
Using a Garley type densometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the time (seconds) for 100 mL of air to pass through the sample was measured according to JIS P 8117. The results are shown in Table 1.

[Porosity]
The ratio of the mass of the fine particles to the total mass of the resin (polyamideimide) or the like used in the production of the filtration filter and the fine particles was defined as the void ratio (mass%) of the filtration filter. The results are shown in Table 1.

[Stress and elongation at break]
A strip-shaped sample was obtained by cutting out a small piece having a size of 4 mm × 30 mm from the polyimide porous membrane (PIm (2)).
Using EZ Test (testing machine, manufactured by Shimadzu Corporation), the stress (MPa; tensile strength) and elongation at break (% GL) at break of the sample were evaluated under the measurement conditions of 5 mm / min. These results are shown in Table 1.

<Manufacturing of resist composition refined product (1)>
(Example 1, Comparative Examples 1 to 3)
A resist solution (1) is prepared by mixing and dissolving each component shown in Table 2, and the resist solution (1) is filtered by each filtration filter to prepare a resist composition refined product (solid content concentration 7). .5% by mass) were produced respectively.

In Table 2, each abbreviation has the following meaning. The value in [] is the blending amount (part by mass).
(A) -1: A polymer compound represented by the following chemical formula (A) -1. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 10100, and the molecular weight dispersion (Mw / Mn) was 1.62. The copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 ^MHz_13 C-NMR) is l / m / n = 40/40/20. there were.

(S) -1: Propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether = 60/40 (mass ratio) mixed solvent.
(B) -1: An acid generator composed of a compound represented by the following chemical formula (B) -1.
(D) -1: Tri-n-octylamine.
(E) -1: Salicylic acid.

(Example 1)
The resist solution (1) was filtered through a filtration filter (1) provided with a polyimide porous membrane (PIm (2)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Comparative Example 1)
The resist solution (1) was filtered through a filtration filter (2) provided with a polyamide (nylon) porous membrane (PAm (d)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Comparative Example 2)
The resist solution (1) was filtered through a filtration filter (3) provided with a polyamide (nylon) porous membrane (PAm (pou)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Comparative Example 3)
The resist solution (1) was filtered through a filtration filter (4) provided with a polyethylene porous membrane (PEm (pou)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

<< Evaluation of resist composition refined products (1) >>
In each example, a resist pattern was formed using the resist composition refined product obtained by filtering with a filtration filter, and the defect was evaluated as follows.

[Formation of resist pattern]
The organic antireflection film composition "ARC29A" (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to dry. As a result, an organic antireflection film having a film thickness of 89 nm was formed.
Next, the resist composition refined products obtained by filtering by the filtration methods of Examples 1 and Comparative Examples 1 to 3 were each applied onto the organic antireflection film using a spinner, and the temperature was 110 ° C. on a hot plate. A resist film having a film thickness of 80 nm was formed by performing a prebake (PAB) treatment under the conditions of 60 seconds and drying.
Next, an ArF excimer laser (193 nm) was applied to the resist film by using an ArF exposure apparatus NSR-S609B (manufactured by Nikon; NA (numerical aperture) = 1.07; Cross poly) via a 6% halftone mask. Irradiated selectively.
Then, it was subjected to post-exposure heating (PEB) treatment at 95 ° C. for 60 seconds, and was further alkaline-developed at 23 ° C. with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution for 10 seconds, and 15 using pure water. Rinse with water for a second and shake off to dry. Then, post-baking was performed at 100 ° C. for 45 seconds.
As a result, in each example, a line-and-space pattern (LS pattern) having a line width of 45 nm and a pitch of 100 nm was formed.

[Evaluation of defects (number of defects)]
With respect to the obtained LS pattern, the total number of defects in the wafer (total number of defects) was measured using a surface defect observation device (manufactured by KLA Tencol Co., Ltd., product name: KLA2371). The results are shown in Table 3. The number of wafers used for such measurement was two for each example, and the average value was adopted.

From the results shown in Table 3, it can be confirmed that by applying the present invention, the occurrence of defects is further suppressed and defects such as scum and microbridge generation are reduced.

<Manufacturing of resist composition refined product (2)>
(Examples 2 to 3, Comparative Examples 4 to 5)
A resist solution (2) is prepared by mixing and dissolving each component shown in Table 4, and the resist solution (2) is filtered by each filtration filter to prepare a resist composition refined product (solid content concentration 7). .5% by mass) were produced respectively.

In Table 4, each abbreviation has the following meaning. The value in [] is the blending amount (part by mass).
(A) -2: A polymer compound represented by the following chemical formula (A) -2. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 25,000, and the molecular weight dispersion (Mw / Mn) was 4.5. The copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 ^MHz_13 C-NMR) is l / m / n / o = 70/5 /. It was 20/5.

(A) -3: A polymer compound represented by the following chemical formula (A) -3. The mass average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 8500, and the molecular weight dispersion (Mw / Mn) was 2.0. The copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 ^MHz_13 C-NMR) is l / m / n = 65/15/20. there were.

(S) -2: Ethyl lactate.
(B) -2: An acid generator composed of a compound represented by the following chemical formula (B) -2.

Add-1: A compound represented by the following chemical formula (Add) -1.
Add-2: Surfactant. Product name Megafuck XR-104 (manufactured by DIC Corporation).

(Example 2)
The resist solution (2) was filtered through a filtration filter (1) provided with a polyimide porous membrane (PIm (2)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Comparative Example 4)
The resist solution (2) was filtered through a filtration filter (2) provided with a polyamide (nylon) porous membrane (PAm (d)) to obtain a refined resist composition.
Filtration conditions: Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Example 3)
The refined resist composition obtained in Comparative Example 4 was further filtered by a filtration filter (1) provided with a polyimide porous membrane (PIm (2)) to obtain a refined resist composition of interest. ..
Filtration conditions by the filtration filter (1): Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

(Comparative Example 5)
The resist composition refined product obtained in Comparative Example 4 is further filtered by a filtration filter (4) provided with a polyethylene porous membrane (PEm (pou)) to obtain a desired resist composition refined product. rice field.
Filtration conditions by the filtration filter (4): Filtration pressure 0.3 kgf / cm ² (2.94 N / cm ² ), temperature 23 ° C.

<< Evaluation of resist composition refined products (2) >>
A resist pattern was formed using the resist composition refined product obtained by filtering with a filtration filter in each example, and the defect was evaluated as follows.

[Formation of resist pattern]
A known organic antireflection film composition is applied onto an 8-inch silicon wafer using a spinner, and then baked on a hot plate at 205 ° C. for 60 seconds to dry, whereby organic reflection having a film thickness of 120 nm is obtained. An antireflection film was formed to prepare an organic antireflection film coated substrate.
Next, the resist composition refined products produced by the production methods of Examples 2 to 3 and Comparative Examples 4 to 5 are respectively applied onto the organic antireflection film-coated substrate using a spinner, and are placed on a hot plate. A resist film having a film thickness of 400 nm was formed by performing a prebake (PAB) treatment at a temperature of 110 ° C. for 60 seconds and drying.
Next, a KrF excimer laser (248 nm) was selectively applied to the resist film by an exposure apparatus NSR-S205C (manufactured by Nikon Corporation; NA = 0.75; 1 / 2annular) via a mask pattern (binary-mask). Irradiated.
Next, a post-exposure heating (PEB) treatment was performed at 140 ° C. for 60 seconds, and then a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution (trade name “NMD-3”, Tokyo Ohka Kogyo Co., Ltd.) was performed at 23 ° C. (Manufactured) was used for 60 seconds of alkaline development.
Then, post-baking was performed at 130 ° C. for 60 seconds.
As a result, in each example, a line-and-space pattern (LS pattern) having a line width of 200 nm and a pitch of 400 nm was formed.

[Evaluation of defects (number of defects)]
With respect to the obtained LS pattern, the total number of defects in the wafer (total number of defects) was measured using a surface defect observation device (manufactured by KLA Tencol Co., Ltd., product name: KLA2371). The results are shown in Table 5. The number of wafers used for such measurement was two for each example, and the average value was adopted.

From the results shown in Table 5, it can be confirmed that by applying the present invention, the occurrence of defects is further suppressed and defects such as scum and microbridge generation are reduced.

1 Spherical cell, 1a Spherical cell, 1b Spherical cell, 5 Communication holes, 10 Polyimide-based resin porous membrane.

Claims (2)

An unfired composite film forming step for forming an unfired composite film containing a polyamic acid, a polyimide or a polyamide-imide, and fine particles, and a step of forming an unfired composite film.
A firing step of heat-treating the unfired composite film film at 120 to 400 ° C. to obtain a polyimide resin-fine particle composite film.
A step of removing fine particles to obtain a polyimide resin porous film by removing the fine particles from the polyimide resin-fine particle composite film.
An etching step of forming a carboxy group and / or a salt-type carboxy group from a part of the imide bond in the polyimide resin molding film.
A re-baking step of heat-treating the polyimide resin porous film after the etching step at 120 to 400 ° C.
A filtration step of passing a chemical solution for lithography through the polyimide resin porous film after the re-baking step, and a filtration step.
Methods for manufacturing lithographic chemical refined products, including. The method for producing a lithographic chemical solution refined product according to claim 1, wherein the lithographic chemical solution contains an organic solvent.

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