WO2020130094A1

WO2020130094A1 - Composition for forming substrate treatment film and method for cleaning semiconductor substrate

Info

Publication number: WO2020130094A1
Application number: PCT/JP2019/049920
Authority: WO
Inventors: 崇片切; 俊青木; 智裕松木; 嘉奈子植田; 和憲高梨; 大貴中津
Original assignee: Jsr株式会社
Priority date: 2018-12-19
Filing date: 2019-12-19
Publication date: 2020-06-25
Also published as: TW202033725A; JPWO2020130094A1

Abstract

The present invention is a composition for forming a substrate treatment film to be used in a method for cleaning a semiconductor substrate, the method being equipped with a step for applying a composition for forming a substrate treatment film to a substrate, and a step for bringing the substrate treatment film formed through the application step into contact with a substrate treatment film removal solution, wherein the composition for forming a substrate treatment film is characterized by containing a polymer and a solvent, the polymer having a C2-20 monovalent hydrocarbon group.

Description

Substrate treatment film forming composition and method for cleaning semiconductor substrate

The present invention relates to a composition for forming a substrate treatment film and a method for cleaning a semiconductor substrate.

In the semiconductor substrate manufacturing process, cleaning is performed to remove particles adhering to the surface of the patterned substrate. In recent years, with the progress of miniaturization of formed patterns, for example, it becomes more difficult to remove particles smaller than the pattern size from the substrate on which the pattern is formed, which causes a reduction in the yield of semiconductor substrates. ing.

Japanese Unexamined Patent Publication No. 7-74137 discloses a method of removing particles on the surface of a substrate by supplying a coating solution to the surface of the substrate to form a thin film and then peeling off the thin film with an adhesive tape or the like. ..

Japanese Unexamined Patent Application Publication No. 2014-99583 discloses that a treatment liquid for forming a film on the surface of a substrate is supplied, solidified or cured, and then all treatment liquids solidified or cured by a removing liquid are dissolved. A substrate cleaning apparatus and a substrate cleaning method for removing the particles are disclosed.

JP, 7-74137, A JP, 2014-99583, A

According to the present invention, in a process of forming a treatment film on a surface of a semiconductor substrate and removing fine particles adhering to the surface of the substrate, the substrate treatment capable of easily removing the particles and the treatment film formed from the substrate surface. An object of the present invention is to provide a film forming composition and a method for cleaning a semiconductor substrate.

The invention made to solve the above problems, a step of applying a substrate treatment film forming composition to the substrate, and a step of contacting a substrate treatment film removal liquid to the substrate treatment film formed by the coating step A composition for forming a substrate treatment film for use in a method for cleaning a semiconductor substrate, comprising: a polymer and a solvent, wherein the polymer has a monovalent hydrocarbon group having 2 to 20 carbon atoms. And

Another invention made to solve the above problems is a step of applying a substrate treatment film forming composition to a substrate, and a substrate treatment film removing liquid is brought into contact with the substrate treatment film formed by the coating step. A method for cleaning a semiconductor substrate, comprising: a step for forming a substrate treatment film containing a polymer and a solvent, wherein the polymer has a monovalent hydrocarbon group having 2 to 20 carbon atoms. Is characterized by.

According to the composition for forming a substrate treatment film and the method for cleaning a semiconductor substrate of the present invention, in the process of forming a treatment film on the surface of a semiconductor substrate and removing fine particles adhering to the substrate surface, the particles and the formed particles are formed. The treated film can be easily removed from the substrate surface. Therefore, the present invention can be suitably used in a manufacturing process of a semiconductor device, which is expected to be further miniaturized in the future.

It is explanatory drawing which shows the composition supply process for substrate treatment film formation in the cleaning method of the semiconductor substrate using the composition for substrate treatment film formation of this invention. It is explanatory drawing which shows formation of the process film in the cleaning method of the semiconductor substrate of this invention. It is explanatory drawing which shows the peeling process liquid supply process in the cleaning method of the semiconductor substrate of this invention.

<Substrate treatment film forming composition>
The composition for forming a substrate treatment film comprises a step of applying a composition for forming a substrate treatment film to a substrate, and a step of bringing a substrate treatment film removing liquid into contact with the substrate treatment film formed by the applying step. It is used for cleaning semiconductor substrates. The composition for forming a substrate treatment film contains a polymer (hereinafter, also referred to as “[A] polymer”) and a solvent (hereinafter, also referred to as “[B] solvent”), and the above-mentioned [A] polymer is It has a monovalent hydrocarbon group having 2 to 20 carbon atoms.

According to the composition for forming a substrate treatment film, a treatment film is formed on the surface of a semiconductor substrate, and by removing the treatment film, particles adhering to the surface of the semiconductor substrate, particularly the semiconductor substrate on which a pattern is formed, are removed. It can be easily removed (hereinafter, also referred to as "particle removability"), and the formed treatment film can be easily removed from the substrate surface (hereinafter, also referred to as "film removability").

The composition for forming a substrate treatment film contains a [A] polymer and a [B] solvent, and the [A] polymer has a monovalent hydrocarbon group having 2 to 20 carbon atoms to remove the film. And excellent particle removability. It is not always clear why the composition for forming a substrate treatment film having the above-mentioned composition exerts the above-mentioned effect, but for example, the polymer [A] is a monovalent hydrocarbon having 2 to 20 carbon atoms. Since it has a group, it is considered that the hydrophobicity becomes appropriate, and as a result, the incorporation of particles into the treatment film formed by the [A] polymer is promoted, and the particle removability is improved, Further, it is considered that the film removability of the treated film is improved.

In addition to the [A] polymer and the [B] solvent, the composition for forming a substrate treatment film has a compound having at least one of a carboxy group and an alcoholic hydroxyl group as a suitable component (hereinafter, also referred to as “[C] compound”). ) May be contained, and other optional components may be contained as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] polymer>
The polymer [A] is a polymer having a monovalent hydrocarbon group having 2 to 20 carbon atoms (hereinafter, also referred to as "group (I)"). "Polymer" refers to a compound having two or more structural units. The lower limit of the molecular weight of the polymer [A] is preferably 300, more preferably 500. The polymer [A] may be used alone or in combination of two or more.

Examples of the group (I) include a monovalent aliphatic hydrocarbon group having 2 to 20 carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent aliphatic hydrocarbon group having 2 to 20 carbon atoms include ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group and t-butyl group. An alkyl group such as ethenyl group, a propenyl group, an alkenyl group such as butenyl group, an ethynyl group, a propynyl group, a monovalent chain hydrocarbon group having 2 to 20 carbon atoms such as an alkynyl group such as butynyl group, a cyclopentyl group, Cycloalkyl group such as cyclohexyl group, cyclopentenyl group, cycloalkenyl group such as cyclohexenyl group, bridged ring saturated hydrocarbon group such as norbornyl group, adamantyl group, tricyclodecyl group, norbornenyl group, tricyclodecenyl group And a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms such as a bridged ring unsaturated hydrocarbon group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl group, tolyl group, xylyl rare, naphthyl group and anthryl group, benzyl group, phenylethyl group, naphthylmethyl group and anthryl group. Examples thereof include aralkyl groups such as a methyl group.

The group (I) is preferably a monovalent aliphatic hydrocarbon group having 2 to 20 carbon atoms, more preferably a monovalent aliphatic hydrocarbon group having 2 to 10 carbon atoms, and an alkyl group having 2 to 6 carbon atoms. Alternatively, a cycloalkyl group having 3 to 6 carbon atoms is more preferable, an ethyl group, a t-butyl group or a cyclohexyl group is particularly preferable, an ethyl group or a t-butyl group is still more preferable, and a t-butyl group is the most preferable. Since the polymer [A] has the above-mentioned groups, it has more appropriate hydrophobicity, and as a result, the film removability and the particle removability can be further improved.

Examples of the [A] polymer include novolac resin, resol resin, aromatic ring-containing vinyl resin, acrylic resin, calixarene resin and the like.

(Novolak resin)
The novolac resin is a chain polymer obtained by reacting a compound having an aromatic ring to which a phenolic hydroxyl group is bonded (hereinafter, also referred to as “phenol compound”) with an aldehyde compound using an acidic catalyst. In the novolak resin having the group (I), the group (I) is usually bonded to the aromatic ring to which the phenolic hydroxyl group is bonded and/or the methylene group derived from the aldehyde compound. When the group (I) is bonded to the benzene ring to which the phenolic hydroxyl group is bonded, the position of the group (I) with respect to the 1-position of the phenolic hydroxyl group in the benzene ring is at any of the 2-position, 3-position and 4-position. It may be.

The novolac resin having a group (I) has, for example, a structural unit represented by the following formula (1) (hereinafter, also referred to as “structural unit (I)”).

In the above formula (1), Ar ¹ is a (p1+q1+r+2)-valent group obtained by removing (p1+q1+r+2) hydrogen atoms on the aromatic ring from an arene having 6 to 20 carbon atoms. X ¹ is a group (I). p1 is an integer of 1 to 9. When p1 is 2 or more, a plurality of X ¹ are the same or different from each other. Y ¹ is a monovalent organic group having 1 to 20 carbon atoms other than the group (I) or a halogen atom. q1 is an integer of 0 to 8. When q1 is 2 or more, a plurality of Y ¹ are the same or different from each other. r is an integer of 1 to 9. However, p1+q1+r is 10 or less. R ¹ is a hydrogen atom or the group (I).

Examples of the arene having 6 to 20 carbon atoms which gives Ar ¹ include benzene, naphthalene, anthracene, phenanthrene, tetracene, pyrene, triphenylene and fluorene. Among these, benzene or naphthalene is preferable, and benzene is more preferable.

"Organic group" refers to a group containing at least one carbon atom. Examples of the monovalent organic group having 1 to 20 carbon atoms include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group containing a divalent hetero atom-containing group between carbon and carbon of the hydrocarbon group, Examples include groups in which a part or all of the hydrogen atoms of the hydrocarbon group and the group containing a hetero atom-containing group are substituted with a monovalent hetero atom-containing group. The monovalent organic group having 1 to 20 carbon atoms other than the group (I) represented by Y ¹ is, for example, a group other than the group (I) among the groups exemplified as the monovalent organic group having 1 to 20 carbon atoms. Groups and the like.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a methyl group and groups similar to the groups exemplified as the above group (I).

Examples of the hetero atom constituting the divalent or monovalent hetero atom-containing group include oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, silicon atom, halogen atom and the like.

Examples of the divalent hetero atom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, and groups in which two or more of these are combined. R'is a hydrogen atom or a monovalent hydrocarbon group. Of these, —O— and —S— are preferred.

Examples of the monovalent hetero atom-containing group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a hydroxy group, a carboxy group, a cyano group, an amino group and a sulfanyl group.

As p1, 1 to 3 is preferable, 1 or 2 is more preferable, and 1 is further preferable.
As q1, 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.
As r, 1 to 3 is preferable, 1 or 2 is more preferable, and 1 is further preferable.
R ¹ is preferably a hydrogen atom.

Examples of the phenol compound having a group (I) which is a raw material compound of a novolac resin include 2-, 3- or 4-ethylphenol, 2-, 3- or 4-t-butylphenol, 2-, 3- or 4- Cyclohexylphenol, 2-, 3- or 4-phenylphenol, 2-, 3- or 4-benzylphenol, 2-, 3-, 4-, 5-, 6-, 7- or 8-t-butylnaphthol, etc. Are listed.

As the aldehyde compound which is the raw material compound of the novolac resin, for example, formaldehyde, acetaldehyde and the like can be used, and as the aldehyde compound having the group (I), for example, propionaldehyde, butyraldehyde, cyclohexanecarboxaldehyde, benzaldehyde, formylpyrene. Etc. can be used. Note that paraformaldehyde may be used instead of formaldehyde, and paraaldehyde may be used instead of acetaldehyde.

Examples of the acidic catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, organic acids such as methanesulfonic acid, paratoluenesulfonic acid, oxalic acid, boron trifluoride, anhydrous aluminum chloride, Lewis acids such as zinc acetate, etc. Can be mentioned. Of these, organic acids are preferable, and paratoluenesulfonic acid is more preferable.

(Resol resin)
The resole resin is a polymer obtained by reacting a phenol compound and an aldehyde compound using a basic catalyst. In the resole resin having the group (I), the group (I) is usually bonded to the aromatic ring to which the phenolic hydroxyl group is bonded and/or the methylene group derived from the aldehyde compound.

Examples of the phenol compound and the aldehyde compound which are the raw material compounds of the resol resin include the same compounds as the phenol compound and the aldehyde compound which are the raw materials of the above novolak resin.

Examples of the basic catalyst include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, lithium hydroxide, potassium hydroxide and calcium hydroxide, amines such as ammonia, triethanolamine, triethylamine and hexamethylenetetramine. Examples thereof include compounds and basic substances such as sodium carbonate.

(Aromatic ring-containing vinyl resin)
The aromatic ring-containing vinyl resin is a polymer having a structural unit derived from a compound having an aromatic ring and a polymerizable carbon-carbon double bond. In the aromatic ring-containing vinyl resin having the group (I), the group (I) is usually bonded to the aromatic ring derived from the above compound.

The aromatic ring-containing vinyl resin having a group (I) has, for example, a structural unit represented by the following formula (2) (hereinafter, also referred to as “structural unit (II)”).

In the above formula (2), R ² is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. Ar ² is a (p2+q2+1)-valent group obtained by removing (p2+q2+1) hydrogen atoms on an aromatic ring from an arene having 6 to 20 carbon atoms. X ² is a group (I). p2 is an integer of 1 to 11. When p2 is 2 or more, a plurality of X ² are the same or different from each other. Y ² is a monovalent organic group having 1 to 20 carbon atoms other than the group (I), a halogen atom or a phenolic hydroxyl group. q2 is an integer of 0 to 10. When q2 is 2 or more, a plurality of Y ² are the same or different from each other.

Examples of the monovalent organic group having 1 to 10 carbon atoms represented by R ² include, for example, the monovalent organic groups having 1 to 20 carbon atoms exemplified in Y ¹ above. Can be given. R ² is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

Examples of the monovalent organic group having 1 to 20 carbon atoms other than the group (I) represented by Y ² include, for example, monovalent organic groups having 1 to 20 carbon atoms other than the above group (I) for Y ^1. The same groups as the above groups can be mentioned.

As p2, 1 to 3 are preferable, 1 or 2 is more preferable, and 1 is still more preferable.
As q2, 0 to 2 is preferable, 0 or 1 is more preferable, and 0 is further preferable.

Examples of the compound providing the structural unit (II) include 2-, 3- or 4-ethylstyrene, 2-, 3- or 4-t-butylstyrene, 2-, 3- or 4-cyclohexylstyrene, 2-, Styrene having a group (I) such as 3- or 4-phenylstyrene, 2-, 3- or 4-benzylstyrene, hydroxy having a group (I) such as 2- or 3-t-butyl-4-hydroxystyrene Examples thereof include styrene, vinylnaphthalene having a group (I) such as 2-, 3-, 4-, 5-, 6-, 7- or 8-t-butyl-1-vinylnaphthalene.

The aromatic ring-containing vinyl resin having the structural unit (II) preferably further has a structural unit containing a phenolic hydroxyl group or an alcoholic hydroxyl group (hereinafter, also referred to as “structural unit (A)”).

Examples of the compound that provides the structural unit (A) include 2-, 3- or 4-hydroxystyrene, hydroxyalkyl (meth)acrylate such as hydroxyethyl (meth)acrylate, hydroxyphenyl (meth)acrylate and the like. (Meth)acrylic acid hydroxyaryl ester and the like can be mentioned.

When the aromatic ring-containing vinyl resin has the structural unit (II) and the structural unit (A), the lower limit of the molar ratio of the structural unit (A) to the structural unit (II) is preferably 5/95, preferably 10/90. Is more preferable, and 20/80 is even more preferable. The upper limit of the molar ratio is preferably 90/10, more preferably 70/30, even more preferably 40/60.

(acrylic resin)
Acrylic resin is a polymer having a structural unit derived from (meth)acrylic acid ester. The acrylic resin having a group (I) is usually formed by using a (meth)acrylic acid ester of a compound having a group (I) as a monomer compound.

The acrylic resin having a group (I) has, for example, a structural unit represented by the following formula (3) (hereinafter, also referred to as “structural unit (III)”).

In the above formula (3), R ³ is a hydrogen atom or a methyl group. R ⁴ is a single bond or a divalent organic group having 1 to 20 carbon atoms. Z is a group (I).

R ³ is preferably a hydrogen atom.

The divalent organic group having 1 to 20 carbon atoms represented by R ⁴ is, for example, a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 20 carbon atoms exemplified in Y ¹ above. Etc. R ⁴ is preferably a single bond.

Examples of the compound giving the structural unit (III) include an alkyl ester of (meth)acrylic acid having 2 or more carbon atoms such as ethyl (meth)acrylate, propyl (meth)acrylate, and t-butyl (meth)acrylate. (Meth)acrylic acid cycloalkyl ester such as cyclohexyl (meth)acrylate, (meth)acrylic acid aryl ester such as phenyl (meth)acrylate, (meth)acrylic acid aralkyl ester such as benzyl (meth)acrylate, ( Examples thereof include alkoxy group-containing alkyl esters of (meth)acrylic acid such as t-butoxyethyl meth)acrylate having 2 or more carbon atoms.

The acrylic resin having the structural unit (III) preferably further has a structural unit represented by the following formula (4) (hereinafter, also referred to as “structural unit (B)”).

In the above formula (4), R ⁵ is a hydrogen atom or a methyl group. R ⁶ is a divalent organic group having 1 to 20 carbon atoms.

R ⁵ is preferably a hydrogen atom.

The divalent organic group having 1 to 20 carbon atoms represented by R ⁶ is, for example, a group obtained by removing one hydrogen atom from the monovalent organic group having 1 to 20 carbon atoms exemplified in the above item Y ^1. Etc. As R ⁶ , a divalent hydrocarbon group is preferable, a divalent chain hydrocarbon group is more preferable, an alkanediyl group is further preferable, and an ethanediyl group is particularly preferable.

Examples of the compound that provides the structural unit (B) include hydroxyethyl (meth)acrylate, hydroxyalkyl (meth)acrylates such as hydroxypropyl (meth)acrylate, and (meth)acrylates such as hydroxycyclohexyl (meth)acrylate. Examples thereof include hydroxycycloalkyl esters of acrylic acid, (meth)acrylic acid hydroxyaryl esters such as (meth)acrylic acid hydroxyphenyl, and (meth)acrylic acid hydroxyaralkyl esters such as (meth)acrylic acid hydroxybenzyl. Among these, (meth)acrylic acid hydroxyalkyl ester is preferable, and (meth)acrylic acid hydroxyethyl is more preferable.

When the acrylic resin has the structural unit (III) and the structural unit (B), the lower limit of the molar ratio of the structural unit (B) to the structural unit (III) is preferably 5/95, more preferably 10/90, 20/80 is more preferable. The upper limit of the molar ratio is preferably 90/10, more preferably 70/30, even more preferably 40/60.

(Calix arene resin)
The calixarene resin is a cyclic oligomer in which a plurality of aromatic rings to which phenolic hydroxyl groups are bonded are cyclically bonded via a hydrocarbon group. In the calixarene resin having the group (I), the group (I) is usually bonded to the aromatic ring to which the phenolic hydroxyl group is bonded and/or the hydrocarbon group.

Examples of the compound that gives the aromatic ring to which the group (I) and the phenolic hydroxyl group are bonded include the same compounds as the phenol compound having the group (I) exemplified as the raw material compound of the above novolak resin. Examples of the hydrocarbon group include a methylene group and a methylene group to which the group (I) is bonded.

The lower limit of the weight average molecular weight (Mw) of the polymer [A] is preferably 1,000, more preferably 2,000, further preferably 3,000, particularly preferably 4,000. The upper limit of Mw is preferably 100,000, more preferably 30,000, further preferably 20,000, particularly preferably 15,000.

As for Mw in this specification, a GPC column (two "G2000HXL", one "G3000HXL" and one "G4000HXL") manufactured by Tosoh Corporation is used, and a flow rate: 1.0 mL/min, an elution solvent: tetrahydrofuran, It is a value measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under analysis conditions of column temperature: 40°C.

As a minimum of the content rate of the [A] polymer in all the components other than the [B] solvent of the composition for substrate treatment film formation, 70 mass% is preferred, 80 mass% is more preferred, and 90 mass% is still more preferred. , 95 mass% is particularly preferable. As a maximum of the above-mentioned content rate, 99.99 mass% is preferred, 99.9 mass% is more preferred, and 99.0 mass% is still more preferred.

The lower limit of the content ratio of the [A] polymer in the substrate treatment film forming composition is preferably 1% by mass, more preferably 3% by mass, further preferably 5% by mass, and particularly preferably 7% by mass. The upper limit of the content ratio is preferably 50% by mass, more preferably 30% by mass, further preferably 20% by mass, and particularly preferably 15% by mass.

<[B] solvent>
The solvent [B] can be used without particular limitation as long as it dissolves or disperses the polymer [A] and optional components contained as necessary. As the solvent [B], one type can be used alone, or two or more types can be used in combination.

Examples of the [B] solvent include organic solvents (hereinafter, also referred to as “[b] organic solvent”), water and the like. When the [B] solvent contains the [b] organic solvent, the lower limit of the content ratio of the [b] organic solvent in the [B] solvent is preferably 70% by mass, more preferably 90% by mass, and further preferably 95% by mass. 99% by mass is particularly preferable. The content ratio of the above-mentioned [b] organic solvent may be 100% by mass. When the solvent [B] contains water, the upper limit of the water content in the solvent [B] is preferably 10% by mass, more preferably 2% by mass, and further preferably 1% by mass. The lower limit of the water content is, for example, 0.01% by mass.

Examples of the organic solvent [b] include alcohol solvents, ketone solvents, ether solvents, ester solvents, nitrogen-containing solvents and the like.

Examples of the alcohol solvent include monoalcohols such as methanol, ethanol, n-propanol and n-butanol, polyhydric alcohols such as ethylene glycol, 1,2-propylene glycol and 1,2-butanediol, propylene glycol monomethyl. Examples thereof include ethers, partial ethers of polyhydric alcohols such as propylene glycol monoethyl ether, and lactic acid esters such as ethyl lactate and butyl lactate.

Examples of ketone solvents include chain ketones such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ketones such as cyclohexanone.

Examples of ether solvents include chain ethers such as n-butyl ether and cyclic ethers such as tetrahydrofuran and 1,4-dioxane.

Examples of the ester solvent include carbonates such as diethyl carbonate, acetic acid esters such as methyl acetate and ethyl acetate, lactones such as γ-butyrolactone, and polyhydric alcohol partial ethers such as diethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. Examples thereof include carboxylates.

Examples of the nitrogen-containing solvent include chain nitrogen-containing compounds such as N,N-dimethylacetamide and cyclic nitrogen-containing compounds such as N-methylpyrrolidone.

As the organic solvent [b], alcohol solvents and/or ester solvents are preferable, polyhydric alcohol partial ethers, lactic acid esters and/or polyhydric alcohol partial ether carboxylates are more preferable, and propylene glycol monoethyl ether. , Ethyl lactate and/or propylene glycol monomethyl ether acetate are more preferred.

The lower limit of the content of the [B] solvent is preferably 100 parts by mass, more preferably 300 parts by mass, further preferably 500 parts by mass, and particularly preferably 700 parts by mass, relative to 100 parts by mass of the [A] polymer. .. The upper limit of the content is preferably 10,000 parts by mass, more preferably 5,000 parts by mass, further preferably 3,000 parts by mass, and particularly preferably 2,000 parts by mass.

The lower limit of the content ratio of the [B] solvent in the composition for forming a substrate treatment film is preferably 50% by mass, more preferably 70% by mass, further preferably 80% by mass, and particularly preferably 85% by mass. The upper limit of the content ratio is preferably 99% by mass, more preferably 97% by mass, further preferably 95% by mass, and particularly preferably 93% by mass.

<[C] compound>
The compound [C] is a compound having at least one of a carboxy group and an alcoholic hydroxyl group (however, a compound corresponding to the solvent [B] is excluded). When the composition for forming a substrate treatment film further contains the compound [C], the film removability can be further improved.

Examples of the [C] compound include organic acids that are not polymers (hereinafter, also referred to as “[c1] organic acid”), alcoholic hydroxyl group-containing compounds (hereinafter, also referred to as “[c2] hydroxyl group-containing compound”) (however, c1] excluding compounds corresponding to organic acids) and the like. The compound [C] can be used alone or in combination of two or more.

The [c1] organic acid is a non-polymeric organic acid. The upper limit of the molecular weight of [c1] organic acid is, for example, 500, preferably 400, and more preferably 300. The lower limit of the molecular weight of [c1] organic acid is, for example, 50, and 55 is preferable. The number of carboxy groups in [c1] organic acid is preferably 1 to 4, and more preferably 1 or 2.

The [c1] organic acid is preferably a carboxylic acid, and more specifically, for example, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, cyclohexanecarboxylic acid, cyclohexylacetic acid, 1-adamantanecarboxylic acid, benzoic acid, A carboxylic acid composed of an aliphatic saturated hydrocarbon group such as phenylacetic acid and/or an aromatic hydrocarbon group and a carboxy group,
Fluorine atom-containing monocarboxylic acids such as difluoroacetic acid, trifluoroacetic acid, pentafluoropropanoic acid, heptafluorobutanoic acid, fluorophenylacetic acid and difluorobenzoic acid,
10-hydroxydecanoic acid, 5-oxohexanoic acid, 3-methoxycyclohexanecarboxylic acid, camphorcarboxylic acid, dinitrobenzoic acid, nitrophenylacetic acid, lactic acid, glycolic acid, glyceric acid, salicylic acid, anisic acid, gallic acid, furancarboxylic acid Monocarboxylic acid containing a hetero atom other than a fluorine atom in a portion other than the carboxy group such as
Monocarboxylic acid compounds such as double bond-containing monocarboxylic acids such as (meth)acrylic acid, crotonic acid, cinnamic acid, sorbic acid,
Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, dodecanedicarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, cyclohexanehexacarboxylic acid, 1,4-naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, Polycarboxylic acids composed of a single bond such as trimellitic acid, pyromellitic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, an aliphatic saturated hydrocarbon group and/or an aromatic hydrocarbon group and a plurality of carboxy groups ,
Partial esterification product of the above polycarboxylic acid,
Fluorine atom-containing polycarboxylic acids such as difluoromalonic acid, tetrafluorophthalic acid, and hexafluoroglutaric acid,
Tartaric acid, citric acid, malic acid, tartronic acid, diglycolic acid, polycarboxylic acid containing a hetero atom other than a fluorine atom in a portion other than the carboxy group such as iminodiacetic acid,
Examples thereof include polycarboxylic acid compounds such as double bond-containing polycarboxylic acids such as maleic acid, fumaric acid and aconitic acid.

As the [c1] organic acid, from the viewpoint of further improving the film removability, a carboxylic acid or polycarboxylic acid having an aliphatic saturated hydrocarbon group and a carboxy group is preferable, and acetic acid or malic acid is more preferable.

The lower limit of the number of alcoholic hydroxyl groups in the [c2] hydroxyl group-containing compound is preferably 2, more preferably 3, and even more preferably 4. The upper limit of the number is 20, for example.

Examples of the [c2] hydroxyl group-containing compound include polyhydric alcohol compounds and sugar compounds.

Examples of the polyhydric alcohol compound include glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, adamantanediol, adamantanetriol, adamantanetetraol, 1,3-dimethyladamantane-5,7-diol, polyethylene glycol, polyvinyl alcohol and the like. Are listed.

Examples of sugar compounds include molasses, molasses, glucose, galactose, xylose, lactose, mannose, talose, rhamnose, arabinose, glucosylmannose, lyxose, allose, altrose, gulose, idose, ribose, erythrose, threose, psicose, fructose. , Sorbose, tagatose, pentulose, tetrose, erythritol, mesoerythritol, sucrose, maltose, isomaltose, cellobiose, lactose, trehalose, kojibiose, sophorose, nigerose, laminaribiose, isomaltose, gentiobiose, melibiose, branteose. , Vicyanose, agarobiose, silabiose, rutinose, primeprose, xylobiose, lodmenabiose, maltitol, lactitol, D-threitol, D-arabinitol, ribitol, xylitol, sorbitol, galactitol, D-mannitol, allitol, higher alditol, aldonic acid, Glucitoses, maltotriose, alginic acid and salts thereof, cyclodextrins, celluloses, starch, dextran, mannan, pectin, pectic acid, chitosan, hyaluronic acid, chondroitin sulfate, heparan sulfate, keratan sulfate and the like can be mentioned.

As the [c2] hydroxyl group-containing compound, a sugar compound is preferable, and erythritol, ribitol, sucrose or trehalose is more preferable.

The lower limit of the solubility of the [C] compound in water at 25° C. is preferably 5% by mass, more preferably 7% by mass, and further preferably 10% by mass. The upper limit of the solubility is preferably 50% by mass, more preferably 40% by mass, further preferably 30% by mass. By setting the solubility in the above range, the film removability can be further improved.

The [C] compound is preferably solid at 25° C. When the [C] compound is solid at 25° C., it is considered that the solid [C] compound is precipitated in the film formed from the composition for forming a substrate-treating film, which can further improve the film removability. it can.

When the composition for forming a substrate treatment film contains a [C] compound, the lower limit of the content of the [C] compound is preferably 0.01 part by mass relative to 100 parts by mass of the [A] polymer, 0.1 part by mass is more preferable, 1 part by mass is further preferable, and 2 parts by mass is particularly preferable. The upper limit of the content is preferably 100 parts by mass, more preferably 50 parts by mass, further preferably 20 parts by mass, and particularly preferably 10 parts by mass. By setting the content of the compound [C] within the above range, the film removability and the particle removability can be further improved.

<Other optional ingredients>
Examples of other optional components include a surfactant and the like. Other optional components may be used alone or in combination of two or more.

The coatability of the composition for forming a substrate-treated film can be further improved by further containing a surfactant. Examples of the surfactant include nonionic surfactants, cationic surfactants and anionic surfactants.

Examples of the nonionic surfactant include ether type nonionic surfactants such as polyoxyethylene alkyl ether, ether ester type nonionic surfactants such as polyoxyethylene ether of glycerin ester, polyethylene glycol fatty acid ester, glycerin ester, sorbitan ester. Ester type nonionic surfactants and the like.

Examples of the above-mentioned cationic surfactants include aliphatic amine salts and aliphatic ammonium salts.

Examples of the anionic surfactants include fatty acid soaps, carboxylates such as alkyl ether carboxylates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, sulfonates such as α-olefin sulfonates, and higher alcohol sulfates. Examples thereof include salts, sulfuric acid ester salts such as alkyl ether sulfates, and phosphoric acid ester salts such as alkyl phosphoric acid esters.

When the composition for forming a substrate treatment film contains a surfactant, the upper limit of the content of the surfactant is, for example, 2 parts by mass with respect to 100 parts by mass of the polymer [A]. The lower limit of the content is, for example, 0.01 part by mass. By setting the content of the surfactant within the above range, the coatability can be further improved.

<Method for preparing composition for forming substrate treatment film>
The composition for forming a substrate-treating film is prepared by mixing arbitrary components such as a polymer [A], a solvent [B], and optionally a compound [C] at a predetermined ratio, and preferably the obtained mixed liquid. Can be prepared, for example, by filtering with a filter having a pore size of 0.1 to 5 μm.

<Semiconductor substrate cleaning method>
The semiconductor substrate cleaning method comprises a substrate processing film forming composition supplying step of supplying a substrate processing film forming composition containing a volatile component to form a film on a substrate to the substrate, and the volatile component volatilizing. By the above, the composition for forming a substrate treatment film is solidified or cured on the substrate, and a peeling treatment liquid supplying step of supplying a peeling treatment liquid for peeling the treatment film from the substrate to the treatment film. .. In the method for cleaning a semiconductor substrate, the above-mentioned composition for forming a substrate treatment film is used as the composition for forming a substrate treatment film.

According to the method for cleaning a semiconductor substrate, since the above-mentioned composition for forming a substrate treatment film is used, a treatment film (hereinafter, also referred to as “treatment film (B)”) is formed on the surface of the semiconductor substrate and the substrate surface is formed. In the process of removing foreign matter, the fine particles on the substrate surface can be efficiently removed, and the formed treatment film (B) can be easily removed from the substrate surface.

An application example of the semiconductor substrate cleaning method will be described in detail with reference to the drawings. Hereinafter, each step will be described.

[Substrate processing film forming composition supplying step]
In this step, a substrate treatment film forming composition containing a volatile component for forming a film on the substrate is supplied to the substrate. The above-mentioned composition for forming a substrate treatment film is used as the composition for forming a substrate treatment film.

The substrate may be a substrate on which no pattern is formed or a substrate on which a pattern is formed.

As the substrate on which the pattern is not formed, for example, a silicon substrate, an aluminum substrate, a nickel substrate, a chromium substrate, a molybdenum substrate, a tungsten substrate, a copper substrate, a tantalum substrate, a metal substrate such as a titanium substrate, a semi-metal substrate, a silicon nitride substrate, or alumina. Examples thereof include substrates, silicon dioxide substrates, tantalum nitride substrates, and ceramic substrates such as titanium nitride. Among these, a silicon substrate, a silicon nitride substrate or a titanium nitride substrate is preferable, and a silicon substrate is more preferable.

As the pattern of the substrate on which the pattern is formed, for example, the line width of the space portion is 2,000 nm or less, 1,000 nm or less, 500 nm or less, and further a line and space pattern or trench pattern of 50 nm or less, or a diameter of 300 nm or less, Examples of the hole pattern include 150 nm or less, 100 nm or less, and further 50 nm or less.

The dimensions of the pattern formed on the substrate are, for example, height of 100 nm or more, 200 nm or more, further 300 nm or more, width of 50 nm or less, 40 nm or less, further 30 nm or less, aspect ratio (pattern height/pattern width ), 3 or more, 5 or more, and more preferably 10 or more fine patterns.

Incidentally, it is preferable that the coating film formed by supplying the substrate treatment film forming composition to the substrate (hereinafter, also referred to as “coating film (A)”) fills the concave portion of the pattern. By embedding the concave portion of the pattern in the coating film (A), the particles attached to the concave portion of the pattern can be removed more efficiently, and a more excellent particle removing effect is exhibited.

Examples of the method for supplying the substrate treatment film forming composition to the substrate include a spin coating method (spin coating), a casting coating method, and a roll coating method. Thereby, the coating film (A) of the composition for forming a substrate treatment film is formed.

First, as shown in FIG. 1A, a substrate processing film forming composition is supplied onto a wafer W. Thereby, the coating film (A) of the composition for forming a substrate treatment film is formed.

Next, as shown in FIG. 1B, the composition for forming a substrate treatment film is formed on the substrate by volatilizing a part or all of the volatile components such as the solvent [B] from the coating film (A) thus formed. The treated film (B) is formed by solidifying or hardening. "Solidification" means solidification, and "curing" means that molecules are linked to increase the molecular weight (for example, crosslinking or polymerization). At this time, the particles attached to the pattern, the wafer W, etc. are taken into the processing film (B) and separated from the pattern, the wafer W, etc.

In this case, the solidification or curing of the coating film (A) can be promoted by heating and/or reducing the pressure of the coating film (A).

The lower limit of the heating temperature for solidification and/or curing is preferably 30°C, more preferably 40°C. The upper limit of the heating temperature is preferably 200°C, more preferably 100°C, and even more preferably 90°C. The lower limit of the heating time is preferably 5 seconds, more preferably 10 seconds, further preferably 30 seconds. The upper limit of the heating time is preferably 10 minutes, more preferably 5 minutes, even more preferably 2 minutes.

The lower limit of the average thickness of the formed treatment film (B) is preferably 10 nm, more preferably 20 nm, even more preferably 50 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm.

[Peeling treatment liquid supply process]
In this step, the treatment film (B) is peeled from the substrate for the treatment film (B) formed by solidifying or curing the composition for forming a substrate treatment film on the substrate by volatilization of the volatile component. A stripping treatment liquid is supplied.

As shown in FIG. 1C, the stripping treatment liquid is supplied onto the treatment film (B). As a result, the processing film (B) is completely removed from the wafer W. As a result, the particles are removed from the wafer W together with the processing film (B).

As the stripping treatment liquid, water, an organic solvent, an alkaline aqueous solution or the like can be used. The peeling treatment liquid is preferably a liquid containing water, more preferably water or an alkaline aqueous solution, and even more preferably an alkaline aqueous solution. An alkaline developer can be used as the alkaline aqueous solution. As the alkaline developer, a known one can be used. Specific examples include an aqueous solution containing at least one of ammonia, tetramethylammonium hydroxide (TMAH) and choline. As the organic solvent, for example, thinner, isopropyl alcohol (IPA), 4-methyl-2-pentanol (MIBC), toluene, acetic acid esters, alcohols, glycols (propylene glycol monomethyl ether, etc.) can be used. .. Further, the treatment film (B) can be removed by sequentially using different types of peeling treatment liquids such as first supplying water as a peeling treatment liquid onto the treatment film (B) and then supplying an alkaline developing solution. Good. By sequentially using different types of stripping treatment liquids, the film removability can be further improved.

By supplying a stripping solution such as an alkali developing solution, a zeta potential of the same polarity (here, negative) is generated on the surface of the wafer W or pattern and the surface of the particles, as shown in FIG. 1C. The particles separated from the wafer W or the like repel each other by being charged with a zeta potential having the same polarity as that of the wafer W or the like. This makes it possible to further suppress reattachment of particles to the wafer W or the like.

As described above, according to the semiconductor substrate cleaning method, particles can be removed with a weaker force as compared with conventional particle removal using physical force, so that pattern collapse can be suppressed. Further, since the particles are removed without utilizing the chemical action, the erosion of the wafer W or the pattern due to the etching action or the like can be suppressed. Furthermore, it is possible to easily remove particles having a small particle size and particles that have entered the gaps of the pattern, which were difficult to remove by the substrate cleaning method using physical force.

The substrate processing film forming composition supplied to the wafer W is finally completely removed from the wafer W. Therefore, the wafer W after cleaning is in a state before the composition for forming a substrate treatment film is supplied, specifically, a state in which the circuit formation surface is exposed.

The above-described semiconductor substrate cleaning method can be performed by various known devices, storage media, and the like. As an example of a suitable apparatus, for example, the substrate cleaning apparatus disclosed in JP-A-2014-99583 can be cited. Specifically, it is formed by a first liquid supply unit that supplies the substrate treatment film forming composition to the semiconductor substrate, and a substrate treatment film forming composition that is supplied to the substrate by the first liquid supplying unit. An example is a semiconductor substrate cleaning apparatus that includes a second liquid supply unit that supplies a removing liquid that dissolves the film onto the film. The storage medium is a computer-readable storage medium that stores a program that operates on a computer and controls the substrate cleaning apparatus, and the program is used to perform the semiconductor substrate cleaning method. As described above, a storage medium or the like that causes a computer to control the substrate cleaning apparatus can be used.

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples. Each physical property in the examples was measured by the following methods.

[Weight average molecular weight (Mw)]
As the polymer Mw, a GPC column (two "G2000HXL", one "G3000HXL", one "G4000HXL" from Tosoh Corp.) was used, and a flow rate: 1.0 mL/min, elution solvent: tetrahydrofuran, column It was measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under the analysis conditions of temperature: 40°C.

<Synthesis of Polymer [A]>
Polymers represented by the following formulas (A-1) to (A-6) and (a-1) to (a-3) (hereinafter, "polymers (A-1) to (A-6) and (A-6) a-1) to (a-3)") were synthesized by the procedure shown below.

In the above formula (A-6), the numerical value attached to each structural unit indicates the content ratio (mol %) of each structural unit to all the structural units constituting the polymer (A-6).

[Synthesis Example 1] (Synthesis of Polymer (A-1))
Under a nitrogen atmosphere, 100 g of 2-ethylphenol, 66.43 g of 37 mass% formaldehyde and 282.94 g of methyl isobutyl ketone were added and dissolved in a reaction vessel. The obtained solution was heated to 40° C., 1.59 g of paratoluenesulfonic acid was added, and the mixture was reacted at 85° C. for 4 hours. The reaction solution was cooled to 30° C. or lower, and the reaction solution was poured into a mixed solution of methanol/water (50/50 (mass ratio)) to reprecipitate. The precipitate was collected with filter paper and dried to obtain the polymer (A-1). The Mw of the polymer (A-1) was 8,000.

[Synthesis Examples 2 to 5] (Synthesis of Polymers (A-2) to (A-5))
The starting compounds were appropriately selected, and the above polymers (A-2) to (A-5) were synthesized in the same manner as in Synthesis Example 1. The Mw of the polymer (A-2) is 7,000, the Mw of the polymer (A-3) is 6,000, the Mw of the polymer (A-4) is 6,000, and the Mw of the polymer (A-5) is Mw was 7,000.

[Synthesis Example 6] (Synthesis of Polymer (A-6))
19.44 g of methyl ethyl ketone was charged into a reaction vessel under a nitrogen atmosphere, and the liquid temperature was raised to 80°C. Separately, a solution prepared from 20.00 g of t-butyl acrylate, 7.77 g of 2-hydroxyethyl acrylate, 2.64 g of 2,2-azobisisobutyrate and 36.10 g of methyl ethyl ketone was heated at 80° C. with respect to the above liquid. It dripped over 3 hours, maintaining. After the dropping, the above polymer (A-6) was obtained by aging at 80° C. for 3 hours. The Mw of the polymer (A-6) was 8,000.

[Comparative Synthesis Examples 1 and 2] (Synthesis of Polymers (a-1) and (a-2))
The starting compounds were appropriately selected, and the above polymers (a-1) and (a-2) were synthesized in the same manner as in Synthesis Example 1. The Mw of the polymer (a-1) was 10,000, and the Mw of the polymer (a-2) was 10,000.

[Comparative Synthesis Example 3] (Synthesis of Polymer (a-3))
A monomer compound was appropriately selected, and in the same manner as in Synthesis Example 6, the polymer (a-3) was synthesized. The Mw of the polymer (a-3) was 8,000.

<Preparation of composition for forming substrate treatment film>
Each component used in the preparation of the composition for forming a substrate treatment film is shown below.

([A] component)
The polymers (A-1) to (A-6) and (a-1) to (a-3) synthesized in the above Synthesis Example were used.

([B] solvent)
B-1: Propylene glycol monoethyl ether B-2: Propylene glycol monomethyl ether acetate B-3: Ethyl lactate B-4: Water

([C] compound)
C-1: erythritol C-2: ribitol C-3: sucrose C-4: trehalose C-5: malic acid C-6: acetic acid

[Example 1]
10 parts by mass of (A-1) as a polymer of [A] was dissolved in 100 parts by mass of (B-1) as a solvent of [B]. The obtained solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare a substrate treatment film forming composition (J-1).

[Examples 2 to 15 and Comparative Examples 1 to 3]
Compositions for forming a substrate treatment film (J-2) to (J-15) and (j-1) were prepared in the same manner as in Example 1 except that the types and contents shown in Table 1 below were used. ~(j-3) were prepared. "-" in Table 1 indicates that the corresponding component was not used.

<Cleaning of semiconductor substrate>
Using the composition for forming a substrate treatment film of Examples 1 to 15 and Comparative Examples 1 to 3, a semiconductor substrate was washed by the following method.

Silica particles with a particle diameter of 80 nm were attached to an 8-inch silicon wafer on which a line-and-space pattern (1L1S, aspect ratio 1) having a line width of the space portion of 1,000 nm was formed. Each substrate treatment film forming composition was supplied onto this silicon wafer, and a substrate on which a treatment film was formed was obtained by a spin coating method under conditions of 1,500 rpm and 30 seconds. After the treatment film is formed, a paddle developing device is used to form a liquid film of a 2.38 mass% tetramethylammonium hydroxide aqueous solution as a peeling treatment liquid on the treatment film, thereby removing the peeling treatment liquid. Immersion was started. After 30 seconds from the start of immersion, the semiconductor substrate was washed by washing with water and drying by a spin dry method.

<Evaluation>
With respect to the cleaned semiconductor substrate, the film removability and the particle removability were evaluated by analyzing the entire surface of the semiconductor substrate using a dark-field defect apparatus (“KLA2800” manufactured by KLA-TENCOR). The evaluation results are also shown in Table 2 below.

The film removability is “A” (extremely good) when the number of residual defects other than silica particles is less than 10/cm ^{2, and} “B” (good) when the number of residual defects is 10/cm ² or more and less than 50/cm ^2. ), and when it was 50 pieces/cm ² or more, it was evaluated as “C” (defective). The particle removability is "A" (extremely good) when the removal rate of silica particles is 90% or more, "B" (good) when 50% or more and less than 90%, and "B" (good) when the removal rate is less than 50%. It was evaluated as "C" (poor).

As shown in Table 2, according to the composition for forming a substrate treatment film of Example, both the film removability and the particle removability were good or extremely good. On the other hand, in the composition for forming a substrate treatment film of Comparative Example, both the film removability and the particle removability were poor.

Claims

A step of applying a substrate treatment film forming composition to the substrate,
A substrate treatment film forming composition used in a method for cleaning a semiconductor substrate, which comprises a step of bringing a substrate treatment film removing liquid into contact with the substrate treatment film formed by the coating step,
Contains a polymer and a solvent,
A composition for forming a substrate treatment film, wherein the polymer has a monovalent hydrocarbon group having 2 to 20 carbon atoms.
The substrate processing film forming composition according to claim 1, wherein the solvent contains an organic solvent, and the content ratio of the organic solvent in the solvent is 90% by mass or more.
The composition for forming a substrate treatment film according to claim 1 or 2, wherein the monovalent hydrocarbon group having 2 to 20 carbon atoms is a monovalent aliphatic hydrocarbon group having 2 to 20 carbon atoms.
The composition for forming a substrate treatment film according to claim 3, wherein the monovalent aliphatic hydrocarbon group having 2 to 20 carbon atoms is a monovalent aliphatic hydrocarbon group having 2 to 10 carbon atoms.
The composition for forming a substrate treatment film according to any one of claims 1 to 4, wherein the polymer is a novolac resin.
The composition for forming a substrate treatment film according to any one of claims 1 to 5, further comprising a compound having at least one of a carboxy group and an alcoholic hydroxyl group.
A step of applying a substrate treatment film forming composition to the substrate,
A substrate treatment film forming composition used in a method for cleaning a semiconductor substrate, which comprises a step of bringing a substrate treatment film removing liquid into contact with the substrate treatment film formed by the coating step,
The composition for forming a substrate treatment film,
Contains a polymer and a solvent,
A method for cleaning a semiconductor substrate, wherein the polymer has a monovalent hydrocarbon group having 2 to 20 carbon atoms.