JP2010145537A - Surface treatment agent for forming resist pattern and resist pattern formation method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment agent for a freezing process, which can suppress variations in the line width of a first resist pattern and LWR (line width roughness) which may be caused by freezing treatment applied to the first resist pattern and the formation of a second resist pattern in a double patterning method, and to provide a resist pattern formation method using the surface treatment agent. <P>SOLUTION: The surface treatment agent for forming a resist pattern contains a compound (A) having an epoxy skeleton or an oxetane skeleton and resin or oligomer (B) which is inactive to the compound (A) and the resist pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a surface treatment agent for forming a resist pattern used in a semiconductor manufacturing process such as an IC, a manufacturing process of a circuit board such as a liquid crystal or a thermal head, and other photofabrication lithography processes, and the same. The present invention relates to a pattern forming method.
Particularly, the present invention relates to a surface treatment agent for forming a resist pattern suitable for exposure with an immersion type projection exposure apparatus using a deep ultraviolet light having a wavelength of 200 nm or less as a light source, and a pattern forming method using the same. is there.

  Since the exposure light source has been shortened to 248 nm using a KrF excimer laser, an image forming method called chemical amplification and a resist suitable for it have been used as a resist image forming method in order to compensate for sensitivity reduction due to light absorption. An example of a positive-type chemical amplification image forming method will be described. When exposed, the acid generator in the exposed area decomposes to generate an acid, and the acid generated in the exposure bake (PEB) is a reaction catalyst. Is used to change an alkali-insoluble group to an alkali-soluble group, and an exposed portion is removed by alkali development.

  With the miniaturization of semiconductor elements, the wavelength of an exposure light source has been shortened and the projection lens has a high numerical aperture (high NA). Currently, an exposure machine using an ArF excimer laser having a 193 nm wavelength as a light source has been developed. The degree of achievement of miniaturization of a semiconductor element can be expressed by resolving power, and can be expressed by the following equation as is generally well known.

(Resolving power) = k ₁ · (λ / NA)
Here, λ is the wavelength of the exposure light source, NA is the numerical aperture of the projection lens, and k ₁ is a coefficient related to the process.

  As a technique for increasing the resolving power, a so-called immersion method has been proposed in which the space between the projection lens and the sample is filled with a liquid having a high refractive index (hereinafter also referred to as “immersion liquid”).

This “immersion effect” means that when λ ₀ is the wavelength of the exposure light in the air, n is the refractive index of the immersion liquid with respect to air, θ is the convergence angle of the light beam, and NA ₀ = sin θ. The above-described resolving power and depth of focus can be expressed by the following equations.

(Resolving power) = k ₁ · (λ ₀ / n) / NA ₀
That is, the immersion effect is equivalent to using an exposure wavelength having a wavelength of 1 / n. In other words, in the case of a projection optical system with the same NA, the depth of focus can be increased n times by immersion.

Further, as a technique for increasing the resolution, a pattern forming method using a special process has been proposed. This is equivalent to decreasing k ₁ in the above-described resolving power equation. One of them is a freezing process (see, for example, Patent Documents 1 to 3 and Non-Patent Documents 1 to 4).

  As described in Non-Patent Document 3 and Non-Patent Document 4, the freezing process is a process in which a first resist pattern is formed on a first resist film and further formed on the first resist pattern. In the double patterning method for forming the second resist pattern on the second resist film, the first resist pattern is treated for the second time by performing chemical or physical treatment on the first resist pattern. It is a process including a step of substantially insolubilizing a resist solvent to be applied and a developing solution. By using the freezing process, it is possible to perform etching after continuing the lithography process from exposure to development twice, and it is possible to reduce the etching process after the first exposure. Here, “substantially insolubilized” with respect to the solvent and developer of the resist to be applied the second time means that the resist that has been applied the second time is insolubilized in the solvent. When the second resist solution is applied onto the resist pattern, the first resist film thickness decreased within the application time (typically within 60 seconds) is within 5% of the initial film thickness. Indicates that

  In Patent Document 1, a treating agent for freezing containing a specific metal compound is allowed to act on a first resist pattern to form a metal oxide film, which is insolubilized in a resist solvent and a developing solution to be applied a second time. A method has been proposed.

  However, in this method, since the metal oxide film is not formed on the second resist pattern, a difference in etching resistance occurs between the first resist pattern and the second resist pattern. It is difficult to control. In order to avoid this, it is conceivable to apply a surface treatment agent to the second resist pattern, but there is a problem that the number of steps increases.

  In Patent Document 3, Non-Patent Document 1 and Non-Patent Document 2, a processing agent for freezing containing a specific resin and a crosslinking agent is allowed to act on the first resist pattern to form a film made of a resin composition of the processing agent. A method of insolubilizing with respect to the solvent and developer of the resist to be applied for the second time has been proposed. However, the method disclosed in Patent Document 3 has a problem that the resist pattern is thickened and the resolution is lowered. In the methods disclosed in Non-Patent Documents 1 and 2, the resist pattern after freezing There was a problem that the line width roughness (LWR) deteriorated.

Further, Patent Document 2 proposes a method of modifying a first resist pattern by irradiating the first resist pattern with vacuum ultraviolet rays so as to insolubilize the resist resist and a developing solution to be applied a second time. However, there is a problem that the dimension of the first resist pattern is reduced.
JP 2008-33174 A JP 2006-18095 A JP 2008-83537 A Proceedings of SPIE, 6153, 615301 (2006) Proceedings of SPIE, 6923, 69230H (2008) Proceedings of SPIE, Vol. 6924, 69240R (2008) Proceedings of SPIE, 6520, 65200F (2007)

  The present invention has been made in view of the above circumstances, and in the double patterning method, the line width of the first resist pattern by the freezing treatment performed on the first resist pattern and the formation of the second resist pattern, and It is an object of the present invention to provide a surface treatment agent for a freezing process capable of suppressing variation in LWR and a resist pattern forming method using the same.

As a result of intensive studies to solve the above problems, the present inventor has reached the present invention shown below.
(1) (A) a compound having an epoxy skeleton or an oxetane skeleton, and (B) a surface treatment for forming a resist pattern comprising a compound (A) and a resin or oligomer that is inert to the resist pattern. Agent.

  (2) The surface treatment agent for forming a resist pattern according to (1), wherein the compound (A) having an epoxy skeleton or an oxetane skeleton has a structure represented by the following general formula (i).

In general formula (i):
R ₁ represents a monovalent organic group.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.
When p is 2 or more, a plurality of R ₁ may be the same or different and may be bonded to each other to form a ring.

  (3) The surface treatment agent for forming a resist pattern according to (2), wherein the compound (A) having a structure represented by the general formula (i) is represented by the following general formula (I): .

In formula (I):
m represents an integer of 1 or more.
R ₁ represents a monovalent organic group.
R ₂ represents an m-valent organic group.
R ₁ and R ₂ may combine with each other to form a ring.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.
When p is 2 or more, a plurality of R ₁ may be the same or different and may be bonded to each other to form a ring.

  (4) The surface treatment agent for forming a resist pattern according to (2), wherein the compound (A) is a resin or oligomer having a group represented by the general formula (i) in the side chain.

  (5) Any one of (1) to (4), wherein the resin or oligomer (B) inert to the compound (A) and the resist pattern is polyalkylene oxide or polyvinyl alcohol. The surface treatment agent for resist pattern formation as described in 2.

  (6) Furthermore, it contains at least one organic solvent selected from alcohol solvents, fluorocarbon solvents and saturated hydrocarbon solvents, any one of (1) to (5) The surface treatment agent for resist pattern formation as described in 2.

  (7) After forming the first resist pattern on the first resist film, the second resist film is formed on the first resist pattern, and the second resist pattern is formed on the second resist film. Any of (1) to (6), wherein the first resist pattern is used after the first resist pattern is formed and before the second resist film is formed in the pattern forming step to be formed. The surface treating agent for forming a resist pattern according to item 1.

(8) forming a first resist pattern using the first resist composition;
A step of treating the first resist pattern with the surface treating agent according to any one of (1) to (7);
Forming a second resist pattern using a second resist composition on the first resist pattern after the surface treatment;
A resist pattern forming method comprising:

  (9) A heating step after the step of surface-treating the first resist pattern using the surface treatment agent according to any one of (1) to (7) and before the step of forming the second resist pattern (8) The resist pattern forming method according to (8).

  According to the present invention, in the freezing process in the double patterning method, the surface treatment agent capable of suppressing the line width variation of the first resist pattern and forming a pattern with good line edge roughness, and pattern formation using the same Can provide a method.

The treatment agent of the present invention will be described in detail below.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what does not have a substituent and what has a substituent. . For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

1. Resist pattern forming surface treatment agent The resist pattern forming surface treatment agent of the present invention is a composition containing a compound (A) and a resin or oligomer (B) described below as essential components, and is a first resist film. Surface treatment agent for the first resist pattern after the step of forming the first resist pattern on the first resist pattern and before the step of forming the second resist film on the first resist pattern and forming the second resist pattern Is preferably used.

[(A) Compound having epoxy skeleton or oxetane skeleton]
The surface treating agent for forming a resist pattern of the present invention contains (A) a compound having an epoxy skeleton or an oxetane skeleton (hereinafter also referred to as “compound (A)”).
The compound (A) preferably includes a structure represented by the following general formula (i).

In general formula (i):
R ₁ represents a monovalent organic group.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.

When p is 2 or more, a plurality of R ₁ may be the same or different, and two R ₁ may be bonded to each other to form a ring.
Examples of the monovalent organic group (R ₁ ) include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonylamino group, and a cyano group.

The alkyl group as the organic group (R ₁ ) may have a substituent, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isopropyl group, isobutyl group, t-butyl group, neopentyl group, 2-ethylhexyl group.

The cycloalkyl group as the organic group (R ₁ ) may have a substituent, may be polycyclic, and may have an oxygen atom in the ring. Specific examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.
The aryl group as the organic group (R ₁ ) may have a substituent, and examples thereof include a phenyl group and a naphthyl group.
The aralkyl group as the organic group (R ₁ ) may have a substituent, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, and a naphthylethyl group.

Alkenyl group as the organic group (R _1), the above alkyl group, and a group having a double bond at an arbitrary position of the cycloalkyl group.
Examples of the alkoxy group as the organic group (R ₁ ) and the alkoxy group in the alkoxycarbonylamino group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a pentyloxy group, a hexyloxy group, and a heptyloxy group. Is mentioned.
Examples of the substituent that each organic group (R ₁ ) may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, a cycloalkyl group, an aryl group, an alkoxy group, and an acyl group. , Acyloxy group, alkoxycarbonyl group, aminoacyl group and the like. As for the cyclic structure in the aryl group, cycloalkyl group and the like, examples of the further substituent include an alkyl group. As for the aminoacyl group, examples of the further substituent include 1 or 2 alkyl groups.

In addition, when p is 2 or more, the ring structure that can be formed by bonding two R ₁ to each other may be a monocyclic ring, a polycyclic ring or an aromatic ring. Preferred specific examples include a cyclohexyl group, a cyclopentyl group, a cyclo ring. Examples include a heptyl group, a cyclooctyl group, a phenyl group, a naphthyl group, a tricyclododecyl group, a norbornyl group, and the like, and may further have the above-described substituent on the ring.

Preferred as the organic group (R ₁ ) is one in which the carbon atom adjacent to the oxygen atom of the cyclic ether represented by the formula (i) is unsubstituted. More preferably, it is a linear alkyl group having 1 to 5 carbon atoms of the organic group (R ₁ ).

Most preferably, it does not have an organic group (R ₁ ) (p = 0).

  Hereinafter, a compound having a structure represented by the general formula (i) when n is 0 is referred to as an epoxy compound, and a compound having a structure represented by the general formula (i) when n is 1 is also referred to as an oxetane compound. To do.

  In one embodiment, the compound (A) is preferably a compound represented by the following general formula (I).

In formula (I):
m represents an integer of 1 or more.
R ₁ represents a monovalent organic group.
R ₂ represents an m-valent organic group.
R ₁ and R ₂ may combine with each other to form a ring.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.
when p is 2 or more, plural R ₁ may be the same or different, it may be bonded to each other to form a ring.

The general formula (I) will be described in detail.
m is preferably 2 or more, more preferably 5 or more. The upper limit of m is not particularly limited, but is preferably 10 or less.

Specific examples of the monovalent organic group represented by R ₁ include the same monovalent organic groups listed for R ₁ in formula (i).
When R ₁ is an organic group, R ₁ and R ₂ may be bonded to each other to form a ring. Examples of the ring structure in which R ₁ and R ₂ are bonded include a cyclopentane ring and a cyclohexane ring. , Cycloheptane ring, cyclooctane ring, norbornane ring, adamantane ring and the like.

R ₂ represents an m-valent organic group. Examples of the organic group (R ₂ ) include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonylamino group, and a cyano group.

The alkyl group as the organic group (R ₂ ) may have a substituent, and may have an oxygen atom, a sulfur atom, or a nitrogen atom in the alkyl chain. Specifically, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, etc. And a branched alkyl group such as isopropyl group, isobutyl group, t-butyl group, neopentyl group and 2-ethylhexyl group.

The cycloalkyl group as the organic group (R ₂ ) may have a substituent, may be polycyclic, and may have an oxygen atom in the ring. Specific examples include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like.

The aryl group as the organic group (R ₂ ) may have a substituent, and examples thereof include a phenyl group and a naphthyl group.

The aralkyl group as the organic group (R ₂ ) may have a substituent, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, and a naphthylethyl group.
Examples of the alkenyl group as the organic group (R ₂ ) include a group having a double bond at an arbitrary position of the alkyl group and the cycloalkyl group.
Examples of the alkoxy group in the organic group (R ₂ ) and the alkoxycarbonylamino group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a pentyloxy group, a hexyloxy group, and a heptyloxy group. Is mentioned.

Examples of the substituent that each organic group (R ₂ ) may have include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxy group, a carbonyl group, a cycloalkyl group, an aryl group, an alkoxy group, and an acyl group. , Acyloxy group, alkoxycarbonyl group, aminoacyl group and the like. As for the cyclic structure in the aryl group, cycloalkyl group and the like, examples of the further substituent include an alkyl group. As for the aminoacyl group, examples of the further substituent include 1 or 2 alkyl groups.

The organic group (R ₂ ) is preferably a case where the carbon atom adjacent to the oxygen atom of the cyclic ether represented by the formula (I) is unsubstituted. Furthermore, the carbon number of R ₂ is preferably 1-30, more preferably 4-20.

Also, those having an aromatic ring in the structure of R ₂ are also preferred. For example, monocyclic aromatic benzene derivatives, compounds in which a plurality of aromatic rings are linked (naphthalene, anthracene, tetracene, etc.), non-benzene aromatic derivatives, etc. Examples of non-benzene aromatic derivatives include pyrrole Residues, furan residues, thiophene residues, indole residues, benzofuran residues, benzothiophene residues and the like can be mentioned.

  Examples of the epoxy compound include aromatic epoxides, alicyclic epoxides, aliphatic epoxides, and the like. As the aromatic epoxide, a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin are used. Di- or polyglycidyl ether produced by the reaction may be mentioned, for example, di- or polyglycidyl ether of bisphenol A or its alkylene oxide adduct, di- or polyglycidyl ether of hydrogenated bisphenol A or its alkylene oxide adduct, and novolak type An epoxy resin etc. are mentioned. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least two cycloalkane rings such as cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Or a cyclopentene oxide containing compound is mentioned preferably.

  Examples of the aliphatic epoxide include diglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof. Typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, or 1,6. -Diglycidyl ether of alkylene glycol such as diglycidyl ether of hexanediol, glycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, diglycidyl ether of ethylene glycol or its adduct of alkylene oxide Diglycidyl ether of polyalkylene glycol represented by diglycidyl ether of propylene glycol or its alkylene oxide adduct, etc. It is below. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.

  Among these polyfunctional epoxy compounds, a preferable epoxy compound is an alicyclic polyfunctional epoxy compound, and an alicyclic polyfunctional epoxy compound in which the alicyclic ring is a cyclohexane ring having 6 carbon atoms is preferable. For example, an epoxy compound made from a compound obtained by polycondensation of 2,2-bis (hydroxyphenyl) -1-butanol and 1,2-epoxy-4-vinylcyclohexane is one of the more preferable ones. A preferred alicyclic polyfunctional epoxy compound having a cyclohexane ring is available, for example, from Daicel Chemical Industries, Ltd. as EHPE3150 (hereinafter referred to as epoxy resin A).

  Examples of polyfunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol. S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) Dipetate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4′-epoxy-6′- Methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate), epoxy Dioctyl hexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin Triglycidyl ether, trimethylolpropane triglycidyl ether, 1,1,3-tetradecadiene dioxide, limonene dioxide, 1,2,7,8-diepoxyoctane, 1,2,5,6-diepoxycyclohexane Examples include octane.

  Examples of the polyfunctional oxetane compound include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)). Bis- (3-ethyloxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1 , 3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenylbis (3-ethyl-3-oxetanylmethyl) ether, Triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3 -Ethyl-3-oxetanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis ( 3-ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl) -3-oxetanylmethyl) ether, dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol tetrakis 3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol hexakis (3-ethyl-3-oxetanylmethyl) ether, caprolactone-modified dipentaerythritol pentakis (3-ethyl-3-oxetanylmethyl) ether, ditri Methylolpropane tetrakis (3-ethyl-3-oxetanylmethyl) ether, EO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO-modified bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO Modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, PO modified hydrogenated bisphenol A bis (3-ethyl-3-oxetanylmethyl) ether, EO modified bisphenol F (3 Polyfunctional oxetane such as ethyl-3-oxetanylmethyl) ether.

In another embodiment, the compound (A) is preferably a resin or oligomer having a structure represented by the general formula (i) in the side chain.
Thus, the main chain skeleton in the case where the compound (A) is a resin or oligomer having an epoxy structure or an oxetane structure in the side chain is not particularly limited, and examples thereof include ethylene and (meth) acrylic acid. The main chain of the repeating unit corresponding to a monomer unit is mentioned.

The weight average molecular weight of the compound (A) as a resin or oligomer is usually 100,000 or less, preferably 5000 to 50000, more preferably 8000 to 30000, as a polystyrene conversion value determined by the GPC method.
Specific examples of the compound (A) as a resin or oligomer include, for example, a resin or oligomer containing a repeating unit corresponding to a monomer having an oxetane structure in the side chain represented by the formula (1).

[Wherein R ³ represents a hydrogen atom or a methyl group, X represents a methylene group or an ethylene group, and R ⁴ represents a methyl group or an ethyl group. ]
Examples of the compound represented by the general formula (1) include 3-methyl-3-methacryloxymethyl oxetane, 3-methyl-3-acryloxymethyl oxetane, 3-ethyl-3-methacryloxymethyl oxetane, 3-ethyl- 3-acryloxymethyl oxetane, 3-methyl-3-methacryloxyethyl oxetane, 3-methyl-3-acryloxyethyl oxetane, 3-ethyl-3-methacryloxyethyl oxetane, 3-ethyl-3-acryloxyethyl oxetane Etc.

  The repeating unit having an oxetane skeleton is a unit derived from the repeating having the oxetane skeleton, but the repeating unit having the oxetane skeleton may be one kind or two or more kinds. Moreover, the copolymer with another monomer may be sufficient.

  Examples of the copolymer include 3-ethyl-3-methacryloxymethyl oxetane / benzyl methacrylate / methacrylic acid copolymer, 3-ethyl-3-methacryloxymethyl oxetane / benzyl methacrylate / methacrylic acid / styrene copolymer. , 3-ethyl-3-methacryloxymethyl oxetane / methyl methacrylate / methacrylic acid copolymer, 3-ethyl-3-methacryloxymethyl oxetane / methyl methacrylate / methacrylic acid / styrene copolymer, and the like.

  Examples of the resin or oligomer containing a repeating unit corresponding to a monomer having an epoxy skeleton in the side chain include those having a repeating unit corresponding to the monomer as shown below.

  When the compound (A) is a copolymer, the content of the monomer having the structure represented by the general formula (i) is usually 3% by mass or more, preferably 5% by mass or more in terms of mass fraction. It is usually 95% by mass or less, preferably 90% by mass or less. Further, the content of the unsaturated carboxylic acid unit is usually 5% by mass or more, preferably 10% by mass or more, and usually 50% by mass or less, preferably 40% by mass or less in terms of mass fraction.

  In addition to the above, JP-A-6-9714, JP-A-2001-31892, 2001-40068, 2001-55507, 2001-310938, 2001-310937, 2001 Epoxy compounds, oxetane compounds, and the like described in each publication such as 220526 can also be used.

[Inactive resin or oligomer]
The treating agent of the present invention contains the above-described compound (A) and an inactive resin or oligomer that does not cause chemical bonding to the resist pattern (hereinafter also simply referred to as “inactive polymer”).

  The inactive resin or oligomer does not form a chemical bond with the compound (A) of the present invention that forms a bond by reacting with a functional group contained in the resist pattern by heating, and does not dissolve the resist pattern. Polymers or oligomers that are soluble in are preferred.

  Examples thereof include polyalkylene oxide, polyalkylene glycol, polyvinyl alcohol, polyvinyl ether, polystyrene, poly (methyl) methacrylate, polyvinyl ester, polyamide, polysiloxane and the like. Among these, polyalkylene oxide, polyalkylene glycol, and polyvinyl alcohol are preferable.

Specific examples of the inert polymer that can be used in the present invention include the following.
Examples of the polyalkylene oxide include polyethylene oxide dialkyl ether, polyethylene oxide diester, polypropylene oxide dialkyl ether, and polypropylene oxide diester.
Examples of the polyalkylene glycol include polyethylene glycol dialkyl ether, polyethylene glycol diester, polypropylene glycol dialkyl ether, and polypropylene glycol diester.

Examples of polystyrene include polystyrene, polyalkyl styrene, polyalkoxy styrene, polyvinyl benzoate, polyvinyl benzoic acid amide, polyhydroxy styrene salt, polyvinyl benzoate, and polystyrene sulfone salt.
Examples of poly (methyl) methacrylate include polyacrylate, polymethacrylate, and polymethacrylate, polyacrylate, polymethacrylamide, and polyacrylate.

Examples of the polyvinyl ether include polymethyl vinyl ether, polyisobutyl vinyl ether, and poly [2- (methoxyethoxy) ethylene].
Polyvinyl acetate is mentioned as a polyvinyl ester.
Examples of the polyamide include polyalanine, polyphenylalanine, polyglycine, polyleucine, polyisoleucine, polyvaline, polymethionine, and copolymers thereof.
Examples of polysiloxane include polydimethylsiloxane.

The weight average molecular weight of the inert polymer is preferably 5000 to 200,000, more preferably 7500 to 100,000, as measured by GPC of polyethylene oxide standard.
Moreover, the content rate of an inert polymer is 1-10 normally by mass ratio with respect to the compound (A) of this invention, Preferably it is 1-6, More preferably, it is a ratio of 1.5-4.

〔solvent〕
As a solvent contained in the surface treatment agent for forming a resist pattern of the present invention, any solvent can be used as long as it does not dissolve the first resist pattern and dissolves the compound (A) and the inert polymer of the present invention. Can also be used. Here, not dissolving the first resist pattern means that when a line and space pattern having a pattern height of 0.2 μm and 200 nm is formed under a condition of 23 ° C. and immersed in an organic solvent for 10 minutes, the pattern It is shown that both the width variation and the pattern height variation are within ± 5%. Examples of such solvents include alcohol solvents, fluorocarbon solvents, saturated hydrocarbon solvents, and the like. Among these solvents, alcohol solvents are preferred from the viewpoint of solubility of the compound (A) of the present invention. The water content of the solvent is preferably 40 mol% or less, more preferably 10 mol% or less, and still more preferably 5 mol% or less.

The alcohol solvent is preferably a monohydric alcohol from the viewpoint of environmental safety, storage stability, and safety to the human body. These can be used alone or in combination.
Specific examples of the monohydric alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, isobutanol, tert-pentanol, n-hexanol, n-heptanol, 2- Heptanol, n-octanol, n-decanol, 3-methyl-3-pentanol, 2,3-dimethyl-2-pentanol, 4-phenyl-2-methyl-2-hexanol, 1-phenyl-2-methyl- Examples include 2-propanol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, 2-ethyl-1-butanol, and n-undecanol. Among these, alcohols having 4 to 11 carbon atoms are preferable. More preferably, it has 7 to 9 carbon atoms. 4 or more carbon atoms are preferable and 7 or more carbon atoms are more preferable in terms of suppression of volatilization of the solvent.

  As the fluorocarbon solvent, perfluoro-2-butyltetrahydrofuran, perfluorotetrahydrofuran, perfluorohexane, perfluoroheptane, perfluorotributylamine, perfluorotetrapentylamine, perfluorotetrahexylamine, etc. can be used. . These organic solvents can be used alone or in combination. Moreover, 40-80 mass% is preferable, and, as for the content rate of the fluorine in a molecule | numerator, More preferably, it is 50-80 mass%.

  Among them, the carbon number of the fluorocarbon solvent is preferably 7 to 12, more preferably 9 to 12. 7 or more carbon atoms are preferable and 9 or more carbon atoms are more preferable in terms of suppression of volatilization of the solvent.

Examples of the saturated hydrocarbon solvent include linear or branched alkanes and cycloalkanes. Specifically, pentane, 2-methylbutane, 3-methylpentane, hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, octane, 2,2,4-trimethylpentane, 2,2,3 -Trimethylhexane, nonane, decane, undecane, dodecane, 2,2,4,6,6-pentamethylheptane, tridecane, pentadecane, tetradecane, hexadecane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc. can be used. . These organic solvents can be used alone or in combination. Terpene-based saturated hydrocarbons can also be used as the solvent, and specifically, cyclic saturated terpenes such as pinane, bornane, caran, fencan, tsujang, o-menthane, m-menthane, and p-menthane are preferable. These saturated hydrocarbon solvents that can be cited preferably have 6 to 10 carbon atoms, more preferably 7 to 9 carbon atoms. 6 or more carbon atoms are preferable and 7 or more carbon atoms are more preferable in terms of suppression of volatilization of the solvent.

  As long as the organic solvent does not dissolve the first resist pattern and dissolves the compound (A) and the inert polymer of the present invention, any organic solvent may be used. Either a fluorocarbon solvent or a saturated hydrocarbon solvent, more preferably 80% by mass or more, and more preferably 100% by mass of an alcohol solvent is used.

  As the other organic solvent, any one or more of ester, ether, ketone, amide, aromatic hydrocarbon and cyclic ketone can be appropriately selected and used. For example, esters such as ethyl lactate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dimethyl glycol monoacetate monomethyl ether, monoethyl ether, or mono Examples thereof include ethers such as phenyl ether and derivatives thereof, cyclic ethers such as dioxane, and ketones such as acetone, methyl ethyl ketone, cyclohexanone, and 2-heptanone.

  The content of the organic solvent in the treating agent is not particularly limited as long as the compound (A) and the inert polymer of the present invention are dissolved, but the total solid content concentration including the compound (A) of the present invention is preferably 98 to 98%. It may be adjusted to 0.001% by mass, more preferably 50 to 0.01% by mass, and still more preferably 30 to 0.05% by mass.

[Surfactant]
The treatment agent of the present invention preferably contains various surfactants. Examples of the surfactant include those that can be used in the “first resist” described later. These surfactants may be used alone or in combination of several.

The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the processing agent.
By adding a surfactant to the treatment agent, the coating property when applying the treatment agent is improved.

  If necessary, the treatment agent of the present invention may further contain a photoacid generator, a photosensitizer, a freezing reaction accelerator other than the acid, a resin, and the like.

2. 1st resist In this invention, after forming a 1st resist pattern on a 1st resist film, the 1st resist pattern is made into 2nd resist liquid with the processing agent of this invention containing a compound (A). In addition, it is important to change so as not to dissolve in the developer. This control can be optimized by changing the properties of the first resist and / or the process conditions when the treatment agent is applied.

Can also be achieved.

The first resist may be either a positive resist or a negative resist, but is preferably a positive resist for the purpose of improving the reactivity with the treatment agent. Here, “positive resist” refers to a resist in which an exposed portion is dissolved in a developer, and “negative resist” refers to a resist in which a non-exposed portion is dissolved in a developer. A positive resist generally uses a chemical reaction such as elimination of an atomic group protecting an alkali-soluble group in order to increase the solubility of an exposed portion in a developer. Employs bond formation between molecules such as cross-linking reaction and polymerization reaction.
The positive resist preferably contains (A) a resin that is decomposed by the action of an acid and increases the solubility in an alkaline developer, and (B) a compound that generates an acid upon irradiation with actinic rays or radiation.

[1] Resin (resin (A)) that is decomposed by the action of an acid to increase the solubility in an alkaline developer
Resin (A) is a resin whose solubility in an alkali developer increases by the action of an acid, and decomposes into the main chain or side chain of the resin or both the main chain and the side chain by the action of an acid and is soluble in alkali. It is a resin having a group that generates a group (hereinafter also referred to as “acid-decomposable group”).
Preferred alkali-soluble groups include carboxyl groups, fluorinated alcohol groups (preferably hexafluoroisopropanol), and sulfonic acid groups.
A preferable group as the acid-decomposable group is a group in which the hydrogen atom of these alkali-soluble groups is substituted with a group capable of leaving with an acid.

Examples of the group leaving with an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), -C (R ₀₁ ) (R ₀₂ ). ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.
The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like. More preferably, it is a tertiary alkyl ester group.
In the resin (A), the repeating unit having an acid-decomposable group is preferably a repeating unit represented by the following general formula (AI).

In general formula (AI),
Xa ₁ represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represents an alkyl group (straight or branched) or a cycloalkyl group (monocyclic or polycyclic).
At least two of Rx _{1 to} Rx ₃ may combine to form a cycloalkyl group (monocyclic or polycyclic).
Examples of the divalent linking group for T include an alkylene group, —COO—Rt— group, —O—Rt— group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a —COO—Rt— group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group or a — (CH ₂ ) ₃ — group.
The alkyl group of Rx _{1 to} Rx ₃ is preferably an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a t-butyl group.

Examples of the cycloalkyl group represented by Rx _{1 to} Rx ₃ include monocyclic cycloalkyl groups such as cyclopentyl group and cyclohexyl group, polycyclic cycloalkyl groups such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group, and adamantyl group. Groups are preferred.
Examples of the cycloalkyl group formed by combining at least two of Rx _{1 to} Rx ₃ include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, A polycyclic cycloalkyl group such as an adamantyl group is preferred.
It is preferable that Rx ₁ is a methyl group or an ethyl group, and Rx ₂ and Rx ₃ are bonded to form the above-described cycloalkyl group.
The atomic group may further have a substituent, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group, a hydroxyl group, and a cyano group.
As for the content rate of the repeating unit which has an acid-decomposable group, 20-50 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 25-45 mol%.
Although the specific example of the repeating unit which has a preferable acid-decomposable group is shown below, this invention is not limited to this.

  The resin (A) preferably further has a repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group.

The repeating unit having a lactone group that can be preferably contained in the resin (A) will be described.
Any lactone group can be used as long as it has a lactone structure, but it is preferably a 5- to 7-membered ring lactone structure, and forms a bicyclo structure or a spiro structure in the 5- to 7-membered ring lactone structure. The other ring structure is preferably condensed. It is more preferable to have a repeating unit having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16). The lactone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and a specific lactone structure is used. This improves line edge roughness and development defects.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. More preferably, they are a C1-C4 alkyl group, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different, and a plurality of substituents (Rb ₂ ) may be bonded to form a ring. .

  Examples of the repeating unit having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AII).

In general formula (AII),
Rb ₀ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom. Examples of the halogen atom for Rb ₀ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Rb ₀ is preferably a hydrogen atom or a methyl group.
Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, or a divalent linking group obtained by combining these. Preferably a single bond, -Ab ₁ -CO ₂ - is a divalent linking group represented by. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbornylene group.
V represents a group having a structure represented by any one of the general formulas (LC1-1) to (LC1-16).

The repeating unit having a lactone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.
As for the content rate of the repeating unit which has a lactone group, 15-60 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 20-50 mol%, More preferably, it is 30-50 mol%.
Particularly preferred repeating units having a lactone group include the following repeating units. By selecting an optimal lactone group, the pattern profile and the density dependence become good.

The repeating unit having a hydroxyl group or a cyano group that can be preferably contained in the resin (A) will be described. When the resin (A) contains the repeating unit, the substrate adhesion and the developer affinity are improved. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. Preferred examples of the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group include a monohydroxyadamantyl group, a dihydroxyadamantyl group, a monohydroxydiamantyl group, a dihydroxyadamantyl group, and a norbornyl group substituted with a cyano group.
Examples of the repeating unit having the atomic group include repeating units represented by the following general formulas (AIIa) to (AIId).

In the formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.
R ₂ c to R ₄ c are in the general formula (VIIa) ~ (VIIc), same meanings as R ₂ c~R ₄ c.
The content of the repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, based on all repeating units in the resin (A). Preferably it is 5-20 mol%.
Specific examples of the repeating unit having a hydroxyl group or a cyano group are given below, but the present invention is not limited thereto.

  The repeating unit having an alkali-soluble group that can be preferably contained in the resin (A) will be described. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulsulfonylimide group, and an aliphatic alcohol (for example, hexafluoroisopropanol group) substituted with an electron-attracting group at the α-position. It is more preferable to have a repeating unit. By containing the repeating unit having an alkali-soluble group, the resolution in contact hole applications is increased. The repeating unit having an alkali-soluble group includes a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or an alkali in the main chain of the resin through a linking group. Either a repeating unit to which a soluble group is bonded, or a polymerization initiator or chain transfer agent having an alkali-soluble group is used at the time of polymerization and introduced at the end of the polymer chain, and the linking group is monocyclic or polycyclic. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid or methacrylic acid.

As for the content rate of the repeating unit which has an alkali-soluble group, 0-25 mol% is preferable with respect to all the repeating units in resin (A), More preferably, it is 3-20 mol%, More preferably, it is 5-15 mol%.
Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto.

  The resin (A) may further have a repeating unit that has an alicyclic hydrocarbon structure and does not exhibit acid decomposability. This can reduce elution of low molecular components from the resist film to the immersion liquid during immersion exposure, and is advantageous in terms of dry etching resistance. Specific examples include a repeating unit represented by the following general formula (III).

In general formula (III), R ₅ represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
Ra represents a hydrogen atom, an alkyl group, or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group.

The cyclic structure possessed by R ₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkenyl having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like, and cycloalkyl groups having 3 to 12 carbon atoms and cyclohexenyl group. Groups. Preferable monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferable examples include a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) Hydrocarbon rings and tricyclic hydrocarbon rings such as homobredan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, and tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring. The bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring such as perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene. A condensed ring in which a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring are condensed is also included.

Preferred examples of the bridged cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferable examples of the bridged cyclic hydrocarbon ring include a norbornyl group and an adamantyl group.

  These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino group protected with a protecting group, and the like. It is done. Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above alkyl group may further have a substituent, and the substituent which may further have a halogen atom, an alkyl group, a hydroxyl group protected with a protecting group, an amino protected with a protecting group The group can be mentioned.

  Examples of the protecting group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups include alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups include methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl groups, and preferred substituted ethyl groups. 1-ethoxyethyl, 1-methyl-1-methoxyethyl, preferred acyl groups include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, pivaloyl groups, etc., aliphatic acyl groups having 1 to 6 carbon atoms, alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The content of the repeating unit represented by the general formula (III) having neither a hydroxyl group nor a cyano group is preferably from 0 to 40 mol%, more preferably based on all repeating units in the resin (A). 0 to 20 mol%.
Specific examples of the repeating unit represented by the general formula (III) are shown below, but the present invention is not limited thereto. In the formula, Ra represents H, CH ₃ , CH ₂ OH, or CF ₃ .

Resin (A) adjusts dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and resolution, heat resistance, sensitivity, etc., which are general required characteristics of resist, in addition to the above repeating structural units. For this purpose, various repeating structural units can be included.
Examples of such repeating structural units include, but are not limited to, repeating structural units corresponding to the following monomers.

Thereby, the performance required for the resin (A), in particular,
(1) Solubility in coating solvent,
(2) Film formability (glass transition point),
(3) Alkali developability,
(4) Membrane slip (hydrophobic, alkali-soluble group selection),
(5) Adhesion of unexposed part to substrate,
(6) Dry etching resistance,
Etc. can be finely adjusted.

  As such a monomer, for example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. Etc.

  In addition, any addition-polymerizable unsaturated compound that can be copolymerized with monomers corresponding to the above various repeating structural units may be copolymerized.

  In the resin (A), the molar ratio of each repeating structural unit is the resist dry etching resistance, standard developer suitability, substrate adhesion, resist profile, and the general required performance of the resist, resolving power, heat resistance, sensitivity. It is set appropriately in order to adjust etc.

  When the positive resist composition of the present invention is for ArF exposure, the resin (A) preferably has no aromatic group from the viewpoint of transparency to ArF light.

  The resin (A) is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, all of the repeating units are methacrylate repeating units, all of the repeating units are acrylate repeating units, or all of the repeating units are methacrylate repeating units and acrylate repeating units. Although it can be used, the acrylate-based repeating unit is preferably 50 mol% or less of the total repeating units. More preferably, the (meth) acrylate repeating unit having an acid-decomposable group represented by the general formula (AI) is 20 to 50 mol%, the (meth) acrylate repeating unit having a lactone group is 20 to 50 mol%, It is a copolymer having 5 to 30 mol% of (meth) acrylate-based repeating units having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and further containing 0 to 20 mol% of other (meth) acrylate-based repeating units. .

  When the positive resist composition of the present invention is irradiated with KrF excimer laser light, electron beam, X-ray, high energy light beam (EUV, etc.) having a wavelength of 50 nm or less, the resin (A) is represented by the general formula (AI). In addition to the repeating unit represented, it is preferable to further have a hydroxystyrene-based repeating unit. More preferably, it has a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected with an acid-decomposable group, and an acid-decomposable repeating unit such as a (meth) acrylic acid tertiary alkyl ester.

  Preferred examples of the repeating unit having an acid-decomposable group include t-butoxycarbonyloxystyrene, 1-alkoxyethoxystyrene, a repeating unit of (meth) acrylic acid tertiary alkyl ester, and the like. The repeating unit by 2-adamantyl (meth) acrylate and dialkyl (1-adamantyl) methyl (meth) acrylate is more preferable.

  Resin (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, it is put into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The concentration of the reaction is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

  The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after the polymerization reaction is completed, a solvent in which the polymer is hardly soluble or insoluble is contacted to precipitate the resin (step a), the resin is separated from the solution (step b), and the resin solution A is dissolved again in the solvent. Preparation (step c), and then contacting the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably a volume amount not more than 5 times). Alternatively, a method including precipitating a resin solid (step d) and separating the precipitated resin (step e) may be used.

  The weight average molecular weight of the resin (A) is preferably 1,000 to 200,000, more preferably 2,000 to 20,000, and even more preferably 3,000 to 15 in terms of polystyrene by GPC method. 1,000, particularly preferably 3,000 to 10,000. By setting the weight average molecular weight to 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and deterioration of developability and film formation due to increase in viscosity can be prevented. it can.

  The degree of dispersion (molecular weight distribution) is usually 1 to 3, preferably 1 to 2.6, more preferably 1 to 2, and particularly preferably 1.4 to 1.7. The smaller the molecular weight distribution, the better the resolution and the resist shape, and the smoother the side wall of the resist pattern, the better the roughness.

In the positive resist composition of the present invention, the blending ratio of the resin (A) in the entire composition is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass in the total solid content. .
In the present invention, the resin (A) may be used alone or in combination.
Hereinafter, although the specific example of the polymer which can be used for this invention is shown, this invention is not necessarily limited only to these.

[2] Compound that generates acid upon irradiation with actinic rays or radiation (component (B))
The positive photosensitive composition of the present invention contains a compound that generates an acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “acid generator”).
As an acid generator, photo-initiator of photocation polymerization, photo-initiator of photo-radical polymerization, photo-decoloring agent of dyes, photo-discoloring agent, or irradiation with actinic ray or radiation used for micro-resist etc. Known compounds that generate acids and mixtures thereof can be appropriately selected and used.

  Examples thereof include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

  Further, a group that generates an acid upon irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, such as US Pat. No. 3,849,137, German Patent No. No. 3914407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used.

Furthermore, compounds capable of generating an acid by light described in US Pat. No. 3,779,778, European Patent 126,712, etc. can also be used.
Preferred compounds among the acid generators include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group.
The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. The two of the group formed by bonding of the R ₂₀₁ to R _203, there can be mentioned an alkylene group (e.g., butylene, pentylene).

Z ⁻ represents a non-nucleophilic anion.
Examples of the non-nucleophilic anion as Z ⁻ include a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methide anion.

  A non-nucleophilic anion is an anion that has an extremely low ability to cause a nucleophilic reaction, and is an anion that can suppress degradation over time due to an intramolecular nucleophilic reaction. This improves the temporal stability of the resist.

Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion, and a camphor sulfonate anion.
Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkylcarboxylate anion.

  The aliphatic moiety in the aliphatic sulfonate anion may be an alkyl group or a cycloalkyl group, preferably an alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms such as methyl. Group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, boronyl group and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include, for example, a nitro group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group , Hydroxyl group, amino group, cyano group, alkoxy group (preferably having 1 to 15 carbon atoms), cycloalkyl group (preferably having 3 to 15 carbon atoms), aryl group (preferably having 6 to 14 carbon atoms), alkoxycarbonyl group ( Preferably 2 to 7 carbon atoms, acyl group (preferably 2 to 12 carbon atoms), alkoxycarbonyloxy group (preferably 2 to 7 carbon atoms), alkylthio group (preferably 1 to 15 carbon atoms), alkylsulfonyl group (Preferably 1 to 15 carbon atoms), alkyliminosulfonyl group (preferably 2 to 15 carbon atoms), ant Ruoxysulfonyl group (preferably having 6 to 20 carbon atoms), alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), alkyloxyalkyloxy group (Preferably having 5 to 20 carbon atoms), a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

Examples of the aliphatic moiety in the aliphatic carboxylate anion include the same alkyl group and cycloalkyl group as in the aliphatic sulfonate anion.
Examples of the aromatic group in the aromatic carboxylate anion include the same aryl group as in the aromatic sulfonate anion.
The aralkyl group in the aralkyl carboxylate anion is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylmethyl group.

  The alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion include, for example, the same halogen atom and alkyl as in the aromatic sulfonate anion Group, cycloalkyl group, alkoxy group, alkylthio group and the like.

Examples of the sulfonylimide anion include saccharin anion.
The alkyl group in the bis (alkylsulfonyl) imide anion and tris (alkylsulfonyl) methide anion is preferably an alkyl group having 1 to 5 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl. Group, sec-butyl group, pentyl group, neopentyl group and the like. Examples of substituents for these alkyl groups include halogen atoms, alkyl groups substituted with halogen atoms, alkoxy groups, alkylthio groups, alkyloxysulfonyl groups, aryloxysulfonyl groups, cycloalkylaryloxysulfonyl groups, and the like. Alkyl groups substituted with fluorine atoms are preferred.
Examples of other non-nucleophilic anions include fluorinated phosphorus, fluorinated boron, and fluorinated antimony.

Examples of the non-nucleophilic anion of Z ⁻ include an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, and an alkyl group. A bis (alkylsulfonyl) imide anion substituted with a fluorine atom and a tris (alkylsulfonyl) methide anion wherein an alkyl group is substituted with a fluorine atom are preferred. More preferably, the perfluoroaliphatic sulfonic acid anion having 4 to 8 carbon atoms, the benzenesulfonic acid anion having a fluorine atom, a bis (alkylsulfonyl) imide anion in which the alkyl group is substituted with a fluorine atom, and the alkyl group being substituted with a fluorine atom Tris (alkylsulfonyl) methide anion.

Examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include the corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.
In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

More preferable (ZI) components include compounds (ZI-1), (ZI-2), and (ZI-3) described below.
The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compounds, namely, compounds containing an arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group with the remaining being an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, and aryldicycloalkylsulfonium compounds.

  The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the aryl group having a heterocyclic structure include a pyrrole residue (a group formed by losing one hydrogen atom from pyrrole) and a furan residue (a group formed by losing one hydrogen atom from furan). Groups), thiophene residues (groups formed by the loss of one hydrogen atom from thiophene), indole residues (groups formed by the loss of one hydrogen atom from indole), benzofuran residues ( A group formed by losing one hydrogen atom from benzofuran), a benzothiophene residue (a group formed by losing one hydrogen atom from benzothiophene), and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

Aryl group, alkyl group of R ₂₀₁ to R _203, cycloalkyl group, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (for example, 6 to 14 carbon atoms) , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group may be substituted. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and linear, branched or cyclic alkoxy groups having 1 to 12 carbon atoms, more preferably carbon. These are an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represents an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, 2-oxocycloalkyl group, alkoxy group. A carbonylmethyl group, particularly preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R ₂₀₁ to R _203, preferably a linear or branched alkyl group having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon Examples thereof include cycloalkyl groups of several 3 to 10 (cyclopentyl group, cyclohexyl group, norbornyl group). More preferred examples of the alkyl group include a 2-oxoalkyl group and an alkoxycarbonylmethyl group. More preferred examples of the cycloalkyl group include a 2-oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched, and a group having> C = O at the 2-position of the above alkyl group is preferable.
The 2-oxocycloalkyl group is preferably a group having> C═O at the 2-position of the cycloalkyl group.

The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having 1 to 5 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group).
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

Next, the compound (ZI-3) will be described.
The compound (ZI-3) is a compound represented by the following general formula (ZI-3), and is a compound having a phenacylsulfonium salt structure.

In general formula (ZI-3),
R _{1c to} R _5c are each independently a hydrogen atom, a linear or branched alkyl group (preferably having 1 to 12 carbon atoms), a cycloalkyl group (preferably having 3 to 8 carbon atoms), a linear or branched alkoxy group. A group (C1-C12 is preferable in the case of a straight chain, C3-C8 is preferable in the case of a branch), or represents a halogen atom.
R _6c and R _7c each independently represent a hydrogen atom, a linear or branched alkyl group (preferably having 1 to 12 carbon atoms) or a cycloalkyl group (preferably having 3 to 8 carbon atoms).
R _x and R _y each independently represents a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group (preferably having 3 to 8 carbon atoms), an allyl group or a vinyl group.
Any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y may be bonded to each other to form a ring structure, and this ring structure includes an oxygen atom and a sulfur atom. , An ester bond and an amide bond may be included.

Zc ⁻ represents a non-nucleophilic anion, and examples thereof include the same non-nucleophilic anion as Z ^{− in} formula (ZI).
R _x and R _y are preferably an alkyl group or cycloalkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more alkyl groups or cycloalkyl groups.

  Preferable specific examples of the compound (ZI-3) include compounds exemplified in paragraphs 0047 and 0048 of JP-A-2004-233661, and paragraphs 0040 to 0046 of JP-A-2003-35948. Can do.

Next, general formulas (ZII) and (ZIII) will be described.
In general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.

The aryl group, alkyl group, and cycloalkyl group of R _{204 to} R ₂₀₇ are the same as the aryl group described as the aryl group, alkyl group, and cycloalkyl group of R _{201 to} R ₂₀₃ in the aforementioned compound (ZI-1). is there.
Aryl group, alkyl group of R ₂₀₄ to R _207, cycloalkyl groups may have a substituent. Examples of this substituent include those that the aryl group, alkyl group, and cycloalkyl group of R _{201 to} R ₂₀₃ in the above-described compound (ZI-1) may have.

Z ⁻ represents a non-nucleophilic anion, and examples thereof include the same as the non-nucleophilic anion of Z ^{− in} formula (ZI).
Examples of the acid generator further include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₈ , R ₂₀₉ and R ₂₁₀ each independently represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.
Among the acid generators, compounds represented by the general formulas (ZI) to (ZIII) are more preferable.

Further, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates monovalent perfluoroalkanesulfonic acid, or a monovalent fluorine atom or fluorine atom. A compound that generates an aromatic sulfonic acid substituted with a group containing fluorinated acid, or a compound that generates a monovalent fluorine atom or imide acid substituted with a group containing a fluorine atom, and even more preferably, It is a sulfonium salt of a substituted alkanesulfonic acid, a fluorine-substituted benzenesulfonic acid, a fluorine-substituted imide acid or a fluorine-substituted methide acid. The acid generator that can be used is particularly preferably a fluorinated substituted alkane sulfonic acid, a fluorinated substituted benzene sulfonic acid or a fluorinated substituted imido acid whose pKa of the generated acid is pKa = -1 or less, and the sensitivity is improved. .
Among acid generators, particularly preferred examples are listed below, but the present invention is not limited thereto.

An acid generator can be used individually by 1 type or in combination of 2 or more types.
The content of the acid generator in the positive photosensitive composition is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, based on the total solid content of the positive photosensitive composition. More preferably, it is 1-7 mass%.

[3] Basic Compound The positive resist composition of the present invention preferably contains a basic compound in order to reduce the change in performance over time from exposure to heating.
Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In general formulas (A) and (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and are a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number). 6-20), wherein R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
About the said alkyl group, as an alkyl group which has a substituent, a C1-C20 aminoalkyl group, a C1-C20 hydroxyalkyl group, or a C1-C20 cyanoalkyl group is preferable.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms.

  The alkyl groups in the general formulas (A) and (E) are more preferably unsubstituted.

  Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds include imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.

  Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole, and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, and 1,8-diazabicyclo [5,4,0. ] Undecar 7-ene etc. are mentioned. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris ( and t-butylphenyl) sulfonium hydroxide, bis (t-butylphenyl) iodonium hydroxide, phenacylthiophenium hydroxide, 2-oxopropylthiophenium hydroxide, and the like. As the compound having an onium carboxylate structure, an anion portion of the compound having an onium hydroxide structure is converted to a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkylcarboxylate. Examples of the compound having a trialkylamine structure include tri (n-butyl) amine and tri (n-octyl) amine. Examples of the aniline compound include 2,6-diisopropylaniline, N, N-dimethylaniline, N, N-dibutylaniline, N, N-dihexylaniline and the like. Examples of the alkylamine derivative having a hydroxyl group and / or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine, and tris (methoxyethoxyethyl) amine. Examples of aniline derivatives having a hydroxyl group and / or an ether bond include N, N-bis (hydroxyethyl) aniline.

  Preferred examples of the basic compound further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.

The amine compound having a phenoxy group, the ammonium salt compound having a phenoxy group, the amine compound having a sulfonate group, and the ammonium salt compound having a sulfonate group have at least one alkyl group bonded to a nitrogen atom. Is preferred. The alkyl chain preferably has an oxygen atom and an oxyalkylene group is formed. The number of oxyalkylene groups is one or more in the molecule, preferably 3 to 9, and more preferably 4 to 6. -CH ₂ CH ₂ O Among the oxyalkylene group _{-, - CH (CH 3)} CH 2 O- or -CH ₂ CH ₂ CH ₂ O- structure is preferred.

  Specific examples of the amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group are exemplified in [0066] of US2007 / 0224539A. The compounds (C1-1) to (C3-3) are exemplified, but not limited thereto.

These basic compounds are used alone or in combination of two or more.
The usage-amount of a basic compound is 0.001-10 mass% normally on the basis of the total solid of a positive resist composition, Preferably it is 0.01-5 mass%.
The mixing ratio of the acid generator and the basic compound in the composition is preferably acid generator / basic compound (molar ratio) = 2.5 to 300. In other words, the molar ratio is preferably 2.5 or more from the viewpoint of sensitivity and resolution, and is preferably 300 or less from the viewpoint of suppressing the reduction in resolution due to the thickening of the resist pattern over time until post-exposure heat treatment. The acid generator / basic compound (molar ratio) is more preferably 5.0 to 200, still more preferably 7.0 to 150.

[4] Surfactant The positive resist composition of the present invention preferably further contains a surfactant, and a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based surfactant, It is more preferable to contain either one or two or more surfactants having both fluorine atoms and silicon atoms.
When the positive resist composition of the present invention contains the above-described surfactant, a resist pattern with good adhesion and low development defects can be obtained with good sensitivity and resolution when using an exposure light source of 250 nm or less, particularly 220 nm or less. It becomes possible.

  Examples of the fluorine-based and / or silicon-based surfactant include, for example, JP-A No. 62-36663, JP-A No. 61-226746, JP-A No. 61-226745, JP-A No. 62-170950, JP 63-34540 A, JP 7-230165 A, JP 8-62834 A, JP 9-54432 A, JP 9-5988 A, JP 2002-277862 A, US Patent Nos. 5,405,720, 5,360,692, 5,529,881, 5,296,330, 5,436,098, 5,576,143, 5,294,511, 5,824,451 Surfactant can be mentioned, The following commercially available surfactant can also be used as it is.

  Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431, 4430 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189 , F113, F110, F177, F120, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Manufactured by Troy Chemical Co., Ltd.), GF-300, GF-150 (manufactured by Toagosei Chemical Co., Ltd.), Surflon S-393 (manufactured by Seimi Chemical Co., Ltd.), F-top EF121, EF122A, EF122B, RF122C, EF125M , EF135M, EF351, 352, EF801, EF802, EF 01 (manufactured by Gemco), PF636, PF656, PF6320, PF6520 (manufactured by OMNOVA), FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D, 222D (manufactured by Neos) Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

  In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.

Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₃ F ₇ group and (poly (oxy) And a copolymer of (ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate).

In the present invention, other surfactants other than fluorine-based and / or silicon-based surfactants can also be used. Specifically, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, etc. Sorbitans such as polyoxyethylene alkyl aryl ethers, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Fatty acid esters, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopa Mite - DOO, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, may be mentioned polyoxyethylene sorbitan tristearate nonionic surfactants of polyoxyethylene sorbitan fatty acid esters such as such.
These surfactants may be used alone or in several combinations.
The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total solid content in the positive resist composition.

[5] Solvent Examples of the solvent that can be used when preparing the positive resist composition by dissolving the above components include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate ester, Organic solvents such as alkyl alkoxypropionates, cyclic lactones (preferably having 4 to 10 carbon atoms), monoketone compounds that may contain rings (preferably having 4 to 10 carbon atoms), alkylene carbonates, alkyl alkoxyacetates, alkyl pyruvates, etc. Can be mentioned.

  Examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl Preferred examples include ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.

  Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate.
Preferable examples of the alkyl alkoxypropionate include ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate.

  Examples of the cyclic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, and γ-octano. Preferred are iclactone and α-hydroxy-γ-butyrolactone.

  Examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2 -Methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one, -Penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methyl Cyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methylcyclo A preferred example is heptanone.

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
Examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2- (2-ethoxyethoxy) ethyl acetate, 3-methoxy-3-methylbutyl acetate, and 1-methoxy-acetate. 2-propyl is preferred.
Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate, and propyl pyruvate.

As a solvent which can be preferably used, a solvent having a boiling point of 130 ° C. or higher under normal temperature and normal pressure can be mentioned. Specifically, cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, acetic acid -2- (2-ethoxyethoxy) ethyl and propylene carbonate are mentioned.
In the present invention, the above solvents may be used alone or in combination of two or more.

In this invention, you may use the mixed solvent which mixed the solvent which contains a hydroxyl group in a structure, and the solvent which does not contain a hydroxyl group as an organic solvent.
Examples of the solvent containing a hydroxyl group include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate, and the like. Particularly preferred are propylene glycol monomethyl ether and ethyl lactate.

  Examples of the solvent not containing a hydroxyl group include propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, butyl acetate, N-methylpyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide and the like. Among these, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethyl ethoxypropionate. 2-heptanone is most preferred.

  The mixing ratio (mass) of the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent not containing a hydroxyl group is particularly preferred from the viewpoint of coating uniformity.

3. Second resist As the second resist used to form the second resist pattern, those described as the first resist can be used as appropriate, but the first resist pattern and the second resist pattern From the viewpoint of making the dry etching resistance the same, the resin used for the second resist is preferably substantially the same as the resin used for the first resist. Furthermore, in order to form a substantially identical pattern between the first resist and the second resist with respect to an actual semiconductor device mask in which patterns of various sizes and shapes exist, Most preferably, the second resist is made of the same resist.

4). Formation of First Resist Pattern In the present invention, the first resist composition is filtered and then applied onto a predetermined support as follows. The filter used for filter filtration is preferably made of polytetrafluoroethylene, polyethylene, or nylon having a pore size of 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less.

  The filtered resist composition is coated on a substrate (eg, silicon / silicon dioxide coating) used for the manufacture of precision integrated circuit elements by a suitable coating method such as a spinner or a coater, and dried to form a resist film. Form. Heating (pre-baking) is preferably performed in the drying stage. The film thickness is preferably adjusted in the range of 50 to 200 nm, more preferably in the range of 70 to 180 nm.

When applying a resist composition with a spinner, the rotation speed is 500-3000 rpm normally, Preferably it is 800-2000 rpm, More preferably, it is 1000-1500 rpm.
Before forming the resist film, an antireflection film may be coated on the substrate in advance.
As the antireflection film, any of an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and amorphous silicon, and an organic film type made of a light absorber and a polymer material can be used. In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, AR-2, AR-3, AR-5 manufactured by Shipley, etc. may be used. it can.

[Dry exposure method]
The resist film is irradiated with actinic rays or radiation through a predetermined mask, preferably baked (heated), developed and rinsed. Thereby, a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, X-ray, electron beam, etc., preferably 250 nm or less, more preferably 220 nm or less, particularly preferably 1 to 1. Far ultraviolet light having a wavelength of 200 nm, specifically, ArF excimer laser, F ₂ excimer laser, EUV (13 nm), and electron beam are preferable, and ArF excimer laser is more preferable.

[Immersion exposure]
Exposure (immersion exposure) may be performed by filling a liquid (immersion medium) having a higher refractive index than air between the resist film and the lens during irradiation with actinic rays or radiation. Thereby, resolution can be improved. As the immersion medium to be used, any liquid can be used as long as it has a higher refractive index than air, but pure water is preferred.

The immersion liquid used for the immersion exposure will be described below.
The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the resist film. Is an ArF excimer laser (wavelength; 193 nm), it is preferable to use water from the viewpoints of availability and ease of handling in addition to the above-mentioned viewpoints.
Further, a medium having a refractive index of 1.5 or more can be used in that the refractive index can be further improved. This medium may be an aqueous solution or an organic solvent.

  When water is used as the immersion liquid, the surface tension of the water is decreased and the surface activity is increased, so that the resist film on the wafer is not dissolved and the influence on the optical coating on the lower surface of the lens element can be ignored. An additive (liquid) may be added in a small proportion. The additive is preferably an aliphatic alcohol having a refractive index substantially equal to that of water, and specifically includes methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. By adding an alcohol having a refractive index substantially equal to that of water, even if the alcohol component in water evaporates and the content concentration changes, an advantage that the change in the refractive index of the entire liquid can be made extremely small can be obtained. On the other hand, when an opaque material or impurities whose refractive index is significantly different from that of water are mixed with 193 nm light, the optical image projected on the resist film is distorted. . Further, pure water filtered through an ion exchange filter or the like may be used.

The electrical resistance of water is desirably 18.3 MQcm or more, the TOC (organic substance concentration) is desirably 20 ppb or less, and deaeration treatment is desirably performed.
Moreover, it is possible to improve lithography performance by increasing the refractive index of the immersion liquid. From such a viewpoint, an additive for increasing the refractive index may be added to water, or heavy water (D ₂ O) may be used instead of water.

  When the resist film made of the positive resist composition of the present invention is exposed through an immersion medium, a hydrophobic resin (HR) can be further added as necessary. As a result, hydrophobic resin (HR) is unevenly distributed on the surface of the resist film, and when the immersion medium is water, the receding contact angle of the resist film surface with respect to the water when the resist film is formed is improved, and the immersion water tracking is improved. Can be made. As the hydrophobic resin (HR), any resin can be used as long as the receding contact angle of the surface can be improved by addition, but a resin having at least one of fluorine atom and silicon atom is preferable. The receding contact angle of the resist film is preferably 60 ° to 90 °, more preferably 70 ° or more. The addition amount can be adjusted and used as appropriate so that the receding contact angle of the resist film falls within the above range, but is preferably 0.1 to 10% by mass based on the total solid content of the positive resist composition, More preferably, it is 0.1-5 mass%. Hydrophobic resin (HR) is ubiquitous at the interface as described above, but unlike a surfactant, it does not necessarily have a hydrophilic group in the molecule, and polar / nonpolar substances are mixed uniformly. There is no need to contribute.

  The receding contact angle is the contact angle measured when the contact line at the droplet-substrate interface recedes, and is useful for simulating the ease of droplet movement under dynamic conditions. It is generally known. In simple terms, it can be defined as the contact angle when the droplet interface recedes when the droplet discharged from the needle tip is deposited on the substrate and then sucked into the needle again. It can be measured by using a contact angle measuring method generally called an expansion / contraction method.

  In the immersion exposure process, the immersion head needs to move on the wafer following the movement of the exposure head to scan the wafer at high speed to form the exposure pattern. In this case, the contact angle of the immersion liquid with respect to the resist film is important, and the resist is required to follow the high-speed scanning of the exposure head without remaining droplets.

The fluorine atom or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or may be substituted on the side chain.
The hydrophobic resin (HR) is preferably a resin having an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms) is a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, It may have a substituent.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have another substituent.
Examples of the aryl group having a fluorine atom include those in which at least one hydrogen atom of an aryl group such as a phenyl group or a naphthyl group is substituted with a fluorine atom, and may further have another substituent.
Preferred examples of the alkyl group having a fluorine atom, the cycloalkyl group having a fluorine atom, or the aryl group having a fluorine atom include groups represented by the following general formulas (F2) to (F4). The present invention is not limited to this.

In general formulas (F2) to (F4),
R _{57 to} R ₆₈ each independently represents a hydrogen atom, a fluorine atom or an alkyl group. However, at least one of R _{57 to} R ₆₁ , R _{62 to} R ₆₄ and R _{65 to} R ₆₈ is a fluorine atom or an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom (preferably having a carbon number of 1 ~ 4). R _{57 to} R ₆₁ and R _{65 to} R ₆₇ are preferably all fluorine atoms. R ₆₂ , R ₆₃ and R ₆₈ are preferably an alkyl group (preferably having 1 to 4 carbon atoms) in which at least one hydrogen atom is substituted with a fluorine atom, and preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Further preferred. R ₆₂ and R ₆₃ may be connected to each other to form a ring.

  Specific examples of the group represented by the general formula (F2) include a p-fluorophenyl group, a pentafluorophenyl group, and a 3,5-di (trifluoromethyl) phenyl group.

  Specific examples of the group represented by the general formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2 -Methyl) isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-t-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro (trimethyl) hexyl group, 2,2 1,3,3-tetrafluorocyclobutyl group, perfluorocyclohexyl group and the like. Hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro (2-methyl) isopropyl group, octafluoroisobutyl group, nonafluoro-t-butyl group and perfluoroisopentyl group are preferable, and hexafluoroisopropyl group and heptafluoroisopropyl group are preferable. Further preferred.

Specific examples of the group represented by the general formula (F4) include, for example, —C (CF ₃ ) ₂ OH, —C (C ₂ F ₅ ) ₂ OH, —C (CF ₃ ) (CH ₃ ) OH, -CH (CF ₃₎ OH and the like, -C (CF _{3) 2} OH is preferred.

Hereinafter, although the specific example of the repeating unit which has a fluorine atom is shown, this invention is not limited to this. Specific examples include repeating units having fluorine atoms, which are contained in the resins (HR-1) to (HR-65) described later.
In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ .
X ₂ represents —F or —CF ₃ .

The hydrophobic resin (HR) is preferably a resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure as a partial structure having a silicon atom.
Specific examples of the alkylsilyl structure or the cyclic siloxane structure include groups represented by the following general formulas (CS-1) to (CS-3).

In general formulas (CS-1) to (CS-3),
R _{12 to} R ₂₆ each independently represents a linear or branched alkyl group (preferably having 1 to 20 carbon atoms) or a cycloalkyl group (preferably having 3 to 20 carbon atoms).
L < ₃ > -L < ₅ > represents a single bond or a bivalent coupling group. As the divalent linking group, an alkylene group, a phenylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a urethane group, or a urea group is used alone or in combination of two or more groups. A combination is mentioned.
n represents an integer of 1 to 5.

Hereinafter, although the specific example of the repeating unit which has group represented by general formula (CS-1)-(CS-3) is given, this invention is not limited to this. In specific examples, X ₁ represents a hydrogen atom, —CH ₃ , —F or —CF ₃ . Specific examples also include a repeating unit having a silicon atom contained in the resins (HR-1) to (HR-65) described later.

  Furthermore, the hydrophobic resin (HR) may have at least one group selected from the following groups (x) to (z).

(X) an alkali-soluble group,
(Y) a group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer;
(Z) A group that decomposes by the action of an acid.

  (X) Alkali-soluble groups include phenolic hydroxyl groups, carboxylic acid groups, fluorinated alcohol groups, sulfonic acid groups, sulfonamido groups, sulfonylimide groups, (alkylsulfonyl) (alkylcarbonyl) methylene groups, (alkylsulfonyl) ( Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris (alkylsulfonyl) ) And a methylene group.

  Preferred alkali-soluble groups include fluorinated alcohol groups (preferably hexafluoroisopropanol), sulfonimide groups, and bis (carbonyl) methylene groups.

  Examples of the repeating unit having an alkali-soluble group (x) include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid or methacrylic acid, or a main group of the resin via a linking group. Examples include repeating units in which an alkali-soluble group is bonded to the chain. Furthermore, a polymerization initiator or a chain transfer agent having an alkali-soluble group can be used at the time of polymerization to be introduced at the end of the polymer chain. Is also preferable.

  The content of the repeating unit having an alkali-soluble group (x) is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the polymer.

  Specific examples of the repeating unit having an alkali-soluble group (x) are shown below, but the present invention is not limited thereto.

  (Y) Examples of the group that decomposes by the action of an alkali developer and increases the solubility in the alkali developer include a group having a lactone structure, an acid anhydride group, an acid imide group, and the like, and preferably a lactone A group having a structure.

  As the repeating unit having a group (y) that is decomposed by the action of an alkali developer and increases the solubility in the alkali developer, an alkali is added to the main chain of the resin, such as a repeating unit of an acrylate ester or a methacrylate ester. A polymerization initiator having a repeating unit to which a group (y) that decomposes by the action of the developer and increases the solubility in an alkali developer is bonded, or a group (y) that increases the solubility in an alkali developer And a chain transfer agent used at the time of polymerization are preferably introduced at the end of the polymer chain.

  The content of the repeating unit having a group (y) whose solubility in an alkali developer is increased is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, still more preferably based on all repeating units in the polymer. 5 to 15 mol%.

  Specific examples of the repeating unit having a group (y) that increases the solubility in an alkali developer include the same repeating units as those having a lactone structure exemplified for the resin of the component (B).

  In the hydrophobic resin (HR), examples of the repeating unit having a group (z) that is decomposed by the action of an acid are the same as the repeating unit having an acid-decomposable group exemplified in the resin of the component (B). . In the hydrophobic resin (HR), the content of the repeating unit having a group (z) that is decomposed by the action of an acid is preferably 1 to 80 mol%, more preferably 10 to 10%, based on all repeating units in the polymer. 80 mol%, more preferably 20 to 60 mol%.

  The hydrophobic resin (HR) may further have a repeating unit represented by the following general formula (IV).

In general formula (IV),
R ₄ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, or a cycloalkenyl group.
L ₆ represents a single bond or a divalent linking group.
In the general formula (IV), the alkyl group of R ₄ is preferably a linear or branched alkyl group having 3 to 20 carbon atoms.
The cycloalkyl group is preferably a cycloalkyl group having 3 to 20 carbon atoms.
The alkenyl group is preferably an alkenyl group having 3 to 20 carbon atoms.
The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20 carbon atoms.
The divalent linking group of L ₆ is preferably an alkylene group (preferably having 1 to 5 carbon atoms) or an oxy group.

  When the hydrophobic resin (HR) has a fluorine atom, the fluorine atom content is preferably 5 to 80% by mass, and 10 to 80% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that the repeating unit containing a fluorine atom is 10-100 mass% in hydrophobic resin (HR), and it is more preferable that it is 30-100 mass%.

When the hydrophobic resin (HR) has a silicon atom, the content of the silicon atom is preferably 2 to 50% by mass and preferably 2 to 30% by mass with respect to the molecular weight of the hydrophobic resin (HR). Is more preferable. Moreover, it is preferable that it is 10-100 mass% in hydrophobic resin (HR), and, as for the repeating unit containing a silicon atom, it is more preferable that it is 20-100 mass%.
The weight average molecular weight of the hydrophobic resin (HR) in terms of standard polystyrene is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and even more preferably 2,000 to 15,000. is there.

  As for the hydrophobic resin (HR), it is preferable that the residual monomer and oligomer components are 0 to 10% by mass, more preferably, as in the resin of the component (B), there are few impurities such as metals. Is more preferably 0 to 5% by mass and 0 to 1% by mass. Thereby, a resist having no change over time such as foreign matter in liquid or sensitivity can be obtained. The molecular weight distribution (Mw / Mn, also referred to as dispersity) is preferably in the range of 1 to 5, more preferably 1 to 3, and still more preferably from the viewpoints of resolution, resist shape, resist pattern sidewall, roughness, and the like. It is the range of 1-2.

  As the hydrophobic resin (HR), various commercially available products can be used, or they can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a monomer polymerization method in which a monomer species and an initiator are dissolved in a solvent and the polymerization is performed by heating, and a solution of the monomer species and the initiator is dropped into the heating solvent over 1 to 10 hours. The dropping polymerization method is added, and the dropping polymerization method is preferable. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, amide solvents such as dimethylformamide and dimethylacetamide, Furthermore, the solvent which melt | dissolves the composition of this invention like the below-mentioned propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone is mentioned. More preferably, the polymerization is performed using the same solvent as the solvent used in the positive resist composition of the present invention. Thereby, generation | occurrence | production of the particle at the time of a preservation | save can be suppressed.

  The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As a polymerization initiator, a commercially available radical initiator (azo initiator, peroxide, etc.) is used to initiate the polymerization. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, or a carboxyl group is preferable. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. The concentration of the reaction is 5 to 50% by mass, preferably 30 to 50% by mass. The reaction temperature is usually 10 ° C to 150 ° C, preferably 30 ° C to 120 ° C, more preferably 60-100 ° C.

  After completion of the reaction, the mixture is allowed to cool to room temperature and purified. Purification can be accomplished by a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water and an appropriate solvent, and a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less. , Reprecipitation method that removes residual monomer by coagulating resin in poor solvent by dripping resin solution into poor solvent and purification in solid state such as washing filtered resin slurry with poor solvent A normal method such as a method can be applied. For example, the resin is precipitated as a solid by contacting a solvent (poor solvent) in which the resin is hardly soluble or insoluble in a volume amount of 10 times or less, preferably 10 to 5 times that of the reaction solution.

  The solvent (precipitation or reprecipitation solvent) used in the precipitation or reprecipitation operation from the polymer solution may be a poor solvent for the polymer, and may be a hydrocarbon, halogenated hydrocarbon, nitro, depending on the type of polymer. A compound, ether, ketone, ester, carbonate, alcohol, carboxylic acid, water, a mixed solvent containing these solvents, and the like can be appropriately selected for use. Among these, as a precipitation or reprecipitation solvent, a solvent containing at least an alcohol (particularly methanol or the like) or water is preferable.

  The amount of the precipitation or reprecipitation solvent used can be appropriately selected in consideration of efficiency, yield, and the like, but generally 100 to 10000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymer solution, More preferably, it is 300-1000 mass parts.

  The temperature for precipitation or reprecipitation can be appropriately selected in consideration of efficiency and operability, but is usually about 0 to 50 ° C., preferably around room temperature (for example, about 20 to 35 ° C.). The precipitation or reprecipitation operation can be performed by a known method such as a batch method or a continuous method using a conventional mixing vessel such as a stirring tank.

  The precipitated or re-precipitated polymer is usually subjected to conventional solid-liquid separation such as filtration and centrifugation, and dried before use. Filtration is performed using a solvent-resistant filter medium, preferably under pressure. Drying is performed at a temperature of about 30 to 100 ° C., preferably about 30 to 50 ° C. under normal pressure or reduced pressure (preferably under reduced pressure).

The resin may be once deposited and separated, and then dissolved again in a solvent, and the resin may be brought into contact with a hardly soluble or insoluble solvent. That is, after completion of the radical polymerization reaction, a solvent in which the polymer is hardly soluble or insoluble is brought into contact, the resin is precipitated (step a), the resin is separated from the solution (step b), and dissolved again in the solvent. (Step c), and then contact the resin solution A with a solvent in which the resin is hardly soluble or insoluble in a volume amount less than 10 times that of the resin solution A (preferably 5 times or less volume). This may be a method including precipitating a resin solid (step d) and separating the precipitated resin (step e).
Specific examples of the hydrophobic resin (HR) are shown below. Table 1 below shows the molar ratio of the repeating units in each resin (corresponding to each repeating unit in order from the left), the weight average molecular weight, and the degree of dispersion.

  Since the resist film is not directly brought into contact with the immersion liquid between the resist film of the positive resist composition of the present invention and the immersion liquid, it is also referred to as an “immersion liquid hardly soluble film” (hereinafter referred to as “top coat”). ) May be provided.

The performance required for the top coat and how to use it are explained in Chapter 7 of "Category and process of immersion lithography" published by CMMC.
From the viewpoint of 193 nm transparency, the top coat is preferably a polymer that does not contain abundant aromatics. Specifically, the polymer contains a hydrocarbon polymer, an acrylate polymer, polymethacrylic acid, polyacrylic acid, polyvinyl ether, and silicon. Examples thereof include a polymer and a fluorine-containing polymer. The aforementioned hydrophobic resin (HR) is also suitable as a top coat. Commercially available top coat materials can also be used as appropriate.

  After the dry exposure or immersion exposure, preferably post-baking (post-heating) is performed, followed by development and rinsing. Thereby, a good pattern can be obtained.

  In the development step, an alkali developer is usually used. As an alkaline developer of the resist composition, inorganic hydroxides such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, primary amines such as ethylamine and n-propylamine, Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide and the like Alkaline aqueous solutions such as quaternary ammonium salts, cyclic amines such as pyrrole and pihelidine can be used.

Furthermore, alcohols and surfactants can be appropriately added to the alkaline developer for use.
The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass.
The pH of the alkali developer is usually from 10.0 to 15.0.

As the rinsing liquid, pure water is usually used, and an appropriate amount of a surfactant can be added and used.
In addition, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing liquid adhering to the pattern with a supercritical fluid can be performed.
Further, after the rinsing process or the supercritical fluid process, a heat treatment can be performed to remove moisture remaining in the pattern.

5). Chemical treatment of the first resist pattern After the first resist pattern is formed using the above method, the chemical treatment (freezing treatment) of the first resist pattern is performed using the treatment agent of the present invention.

[Washing with acid]
First, it is preferable to wash the first resist pattern with a solution containing an acid different from the treatment agent of the present invention. Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as carboxylic acid, sulfonic acid, sulfonylimide acid, and methide acid. Among these, carboxylic acid, sulfonic acid, and imide Organic acids such as acid and methide acid are preferred.

Examples of carboxylic acids include alkyl sulfonic acids such as acetic acid and propionic acid, fluoroalkyl carboxylic acids such as perfluoroalkyl carboxylic acids having 1 to 8 carbon atoms, and aromatic carboxylic acids such as benzoic acid and pentafluorobenzoic acid. .
Examples of the sulfonic acid include butanesulfonic acid, hexanesulfonic acid, alkylsulfonic acid such as C1-C8 perfluoroalkylsulfonic acid, and aromatic sulfonic acid such as p-toluenesulfonic acid and pentafluorobenzenesulfonic acid. It is done.

Examples of imido acids include bis (alkylsulfonyl) imidic acid having 1 to 8 carbon atoms, bis (perfluoroalkylsulfonyl) imidic acid having 1 to 8 carbon atoms, cyclic disulfonylimide acid having 5 to 8 members, and fluorination. Examples thereof include disulfonylimide acids such as 5- to 8-membered cyclic disulfonylimide acids having an alkylene chain.
Examples of the methide acid include trisulfonylmethide acids such as tris (alkylsulfonyl) methido acid having 1 to 8 carbon atoms and tris (fluoroalkylsulfonyl) methido acid having 1 to 8 carbon atoms.

  Among these, perfluoroalkyl carboxylic acids, sulfonic acids, imide acids, and methide acids are preferable, and perfluoroalkyl sulfonic acids, aromatic sulfonic acids, imide acids, and methide acids are more preferable.

The solvent of the solution may be any solvent in which the resist pattern does not dissolve and the acids dissolve, and includes, for example, water and a solvent used in the treatment agent of the present invention, preferably a solvent used in the treatment agent of the present invention. Is used.
The concentration of the acid is 0.1 to 10 mol%, preferably 0.5 to 5 mol%, and more preferably 0.5 to 3 mol%.

  As a preferred treatment method, an acid solution is padded on the substrate on which the first resist pattern is formed, and after a while, the substrate is rotated and shaken off, and the substrate is washed with a solvent.

  The longer the contact time between the solution and the resist pattern after padding the solution is 5 seconds or longer, the better, but considering the throughput, it is preferably 3 minutes or less, more preferably 2 minutes or less, and 1 minute or less. Most preferred.

  Moreover, it is preferable to use the solvent used for the acid solution as the solvent for washing the substrate with a solvent in order to remove excess acid from the substrate.

  In the cleaning method, the solvent is discharged at the center of the substrate at a flow rate of 0.5 to 5 ml / sec for 5 to 30 seconds while rotating the substrate at 50 to 500 rpm, and then the substrate is discharged at 500 to 3000 rpm for 10 to 60 seconds. Although the method of rotating and shaking off a solvent is preferable, it is not limited to this.

[Chemical treatment]
Next, a method for chemical treatment of the first resist pattern using the treating agent of the present invention will be described.
Examples of the method for bringing the treatment agent into contact with the resist pattern include a method of immersing the resist pattern in the treatment agent and a method of applying the treatment agent on the resist pattern.
As a method of immersing, a method of padding the treatment agent on the substrate on which the first resist pattern is formed is preferable.
The longer the time during which the processing agent is padded on the substrate and the processing agent is in contact with the resist pattern is longer than 5 seconds, it is better. However, considering the throughput, it is preferably 3 minutes or less, more preferably 2 minutes or less. Most preferred is 1 minute or less.
Moreover, although the temperature in a processing apparatus and the temperature of a processing agent can be made higher than room temperature in order to advance reaction, the temperature of 50 degrees C or less is preferable from a safety viewpoint.

  Also, spin coating is preferred as a method for applying the treating agent on the resist pattern. In the case of spin coating, the processing agent is discharged to the center of the substrate for 0.5 to 5 seconds at a flow rate of 0.5 to 5 ml / second while rotating the substrate at 50 to 500 rpm, and then the substrate is driven at 10 to 500 to 3000 rpm. It is preferable to rotate for 60 seconds to shake off excess treatment agent and apply the treatment agent.

In the present invention, it is preferable to heat the substrate after the dipping / coating or in parallel with the dipping / coating in order to advance the reaction between the treating agent of the present invention and the resist pattern.
Usually, the heating temperature is preferably 60 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. or higher and 180 ° C. or lower, and most preferably 90 ° C. or higher and 150 ° C. or lower. The heating time is preferably from 10 seconds to 300 seconds, and more preferably from 30 seconds to 150 seconds. When the treatment agent of the present invention contains a polymer or oligomer, a film of the treatment agent is formed on the substrate by the above process.

  After reacting the treating agent with the resist pattern, it is preferable to wash the substrate with a solvent in order to remove excess treating agent from the substrate. As the solvent in this case, it is preferable to use pure water or the solvent used in the treatment agent. The cleaning method is as follows. First, a paddle is formed on the substrate with a solvent and allowed to stand, and then the solvent is rotated at 50 to 500 rpm while the solvent is rotated at a flow rate of 0.5 to 5 ml / second at the center of the substrate. A method is preferred in which the excess processing solvent is shaken off while discharging the substrate for 2 seconds and rotating the substrate at 500 to 3000 rpm for 10 to 60 seconds, but is not limited thereto.

  Furthermore, it is preferable to add a heating step in order to remove the cleaning solvent. The heating temperature is preferably 60 ° C. or higher and 200 ° C. or lower, more preferably 70 ° C. or higher and 170 ° C. or lower, and most preferably 80 ° C. or higher and 150 ° C. or lower. The heating time is preferably 30 seconds or longer and 120 seconds or shorter, and more preferably 40 seconds or longer and 100 seconds or shorter. Further, instead of heating, the solvent may be removed by blowing the substrate with an inert gas such as nitrogen gas.

6). Formation of Second Resist Pattern In the present invention, the second resist composition is filtered and then applied to a substrate on which a first resist pattern that has already been chemically treated is formed. The filter filtration is the same as in the first resist pattern.

  The second resist composition is applied onto the first resist pattern that has been subjected to chemical treatment (freezing treatment) in the same manner as the formation of the first resist pattern to form a resist film. For the subsequent steps of forming the second resist pattern, such as drying (pre-baking), exposure, post-baking, development, and rinsing, the same methods as those described as the first resist pattern forming method can be applied. It is. Thus, a second resist pattern different from the first resist pattern can be formed.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.
<Preparation of resist composition>
[Synthesis of Resin (1)]
Under a nitrogen stream, 20 g of a 6/4 (mass ratio) mixed solvent of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether was placed in a three-necked flask and heated to 80 ° C. (solvent 1). Butyrolactone methacrylate, hydroxyadamantane methacrylate and 2-methyl-2-adamantyl methacrylate are dissolved in a mixed solvent of 6/4 (mass ratio) of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether at a molar ratio of 50/10/40. A 22 mass% monomer solution (200 g) was prepared. Furthermore, 8 mol% of initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the monomer, and the dissolved solution was added dropwise to (solvent 1) over 6 hours. After completion of dropping, the reaction was further carried out at 80 ° C. for 2 hours. The reaction solution was allowed to cool and then poured into 1800 ml of hexane / 200 ml of ethyl acetate. The precipitated powder was collected by filtration and dried to obtain 37 g of Resin (1).
As a result of GPC measurement using polystyrene as a standard, the obtained resin (1) had a weight average molecular weight (Mw) of 10,000 and a dispersity (Mw / Mn) of 1.8.

[Synthesis of Resins (2) to (4) and (1b) to (3b)]
Resins (2), (3), (4) and (1b), (2b), (3b) were synthesized by the same synthesis method as for resin (1).
The structures of the repeating units in the resins (1) to (4) and (1b) to (3b) are shown below, the composition ratio of the repeating units (corresponding to each repeating unit in order from the left), the weight average molecular weight (Mw), and the dispersion The degree (Mw / Mn) is shown in Table 2.

[Preparation of resist]
The components shown in Table 3 below were dissolved in a solvent, and a solution with a solid content of 3.5% by mass was prepared for each, and this was filtered through a 0.1 μm polyethylene filter to form positive resist compositions Ar-01 to Ar. -04 was prepared.

  The (b) acid generator, (c) basic compound, (d) surfactant, and solvent shown in Table 3 are as follows.

[(B) Acid generator]

[(C) Basic compound]
TPI: 2,4,5-triphenylimidazole PEA: N-phenyldiethanolamine DPA: 2,6-diisopropylphenyl alcohol PBI: 2-phenylbenzimidazole [(d) Surfactant]
W-1: MegaFuck F176 (Dainippon Ink Chemical Co., Ltd.) (Fluorine)
W-2: Megafuck R08 (Dainippon Ink Chemical Co., Ltd.) (fluorine and silicon)
W-3: Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) (silicon-based)
〔solvent〕
A1: Propylene glycol monomethyl ether acetate A2: γ-butyrolactone A3: Cyclohexanone B1: Propylene glycol monomethyl ether B2: Ethyl lactate <Preparation of surface treatment agent>
Compound (A)]
(Polymer A1)
Methacrylic acid / benzyl methacrylate / 3-ethyl-3-methacryloxymethyloxetane copolymer (30/30/40 (molar ratio))
(Polymer A2)
Ortho-cresol novolac epoxy resin (ECON 1020; Nippon Kayaku)
(Polymer A3)
Polyfunctional cyclohexane epoxy resin having an epoxy group on the cyclohexane ring (epoxy equivalent: about 180 g / eq) (trade name: EHPE3150, manufactured by Daicel Chemical Industries, Ltd.)
(Polymer A4)
Carboxytetracyclododecyl methacrylate / 3,4 epoxy tricyclo [5,2,1,0 ²⁶ ] decyl acrylate

(Synthesis method of polymer A1)
In a 500 ml three-necked flask equipped with a stirrer, a condenser and a thermometer, methacrylic acid (25.8 g), benzyl methacrylate (105.7 g), and 3-ethyl-3-methacryloxymethyloxetane (18.4 g) were added. Dissolved in propylene glycol monomethyl ether acetate (278.5 g), azobisisobutyronitrile (3.6 g) was added thereto, and the mixture was stirred for 5 hours while maintaining the internal temperature at 65 to 75 ° C. in a nitrogen atmosphere. Purification was performed according to a conventional method to obtain polymer A1.

(Synthesis method of polymer A4)
In a 100 ml three-necked flask equipped with a stirrer, a condenser and a thermometer, 1.45 g of carboxytetracyclododecyl methacrylate and 3,4-epoxytricyclo [5.2.1.0 ^2,6 ] decyl acrylate11. 2 g was dissolved in 29.5 ml of dry tetrahydrofuran, 200 mg of azobisisobutyronitrile was added thereto, and the mixture was stirred for 2 hours while maintaining the internal temperature at 60 to 65 ° C. in a nitrogen atmosphere. Purification was performed according to a conventional method to obtain polymer A4.

  The components shown in Table 4 below were dissolved in a solvent, and each of the obtained solutions was filtered through a polyethylene filter having a pore size of 0.1 μm to prepare a freezing treatment agent (surface treatment agent). In Table 4, values in parentheses represent parts by mass.

(Chemical species)
I-1: Tetraisocyanate silane (Matsumoto Fine Chemical Co., Ltd. trade name: ORGATIX SI-400)
(Inert polymer)
P1: Poly (ethylene oxide) (weight average molecular weight 1000000, Aldrich Corporation)
P2: Polyvinyl alcohol (weight average molecular weight 130000, Aldrich Corporation)
(catalyst)
D1: Nonafluoro-1-butanesulfonic acid D2: 1,8-diazabicyclo [5.4.0] -7-undecene (Tokyo Chemical Industry)
(solvent)
C1: n-butanol C2: Isopropanol <Pattern formation method for freezing process>
Using the prepared surface treatment agent and resist composition, a pattern was formed by the following method and evaluated.

[Formation of pattern]
(Examples 1-12)
Hereinafter, a pattern forming method subjected to a freezing process will be described with reference to FIG.
An organic antireflection film (ARC29A (manufactured by Nissan Chemical Industries)) was applied on the silicon wafer 5 and baked at 205 ° C. for 60 seconds to form an antireflection film 4 having a thickness of 78 nm. The first resist composition prepared thereon was uniformly applied by spin coating, and baked at 110 ° C. for 60 seconds to form a first resist film 1 having a film thickness of 80 nm (FIG. 1A). .

  Next, the wafer coated with the resist film 1 was subjected to immersion pattern exposure using an ArF excimer laser scanner (TWINSCAN XT: 1700Fi manufactured by ASML) through an exposure mask m1 (line / space = 1/1) (FIG. 1 (b)). Pure water was used as the immersion liquid. The exposure amount was optimized so as to obtain a desired line width. Thereafter, the mixture was heated at 120 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and spin-dried. Further, the remaining water was removed by heating at 90 ° C. for 90 seconds to obtain a first resist pattern 1a having a pitch of 100 nm and a line width of 50 nm (FIG. 1C).

  Subsequently, the surface treatment agent (freezing agent) of the present invention is spin-coated on the substrate to a desired film thickness by adjusting the rotation speed (FIG. 1 (d)), and baked at 100 ° C. for 90 seconds to form a film. The reaction was allowed to proceed while forming a surface treating agent film 10 having a thickness of 150 nm (FIG. 1 (e)). Thereafter, in order to remove excess processing agent, the same solvent as that used for the processing agent is discharged from the nozzle n at a flow rate of 2 cc / sec for 5 seconds to form a paddle at the center of the substrate, and the substrate is left to stand for 30 seconds. The solvent is placed in contact with the surface treatment agent film, and further the substrate is rotated at 300 rpm. The solvent is discharged at the flow rate of 1 ml / second for 10 seconds at the center of the substrate, and then the substrate is rotated at 2000 rpm for 30 seconds. The solvent was shaken off. In order to remove the solvent remaining on the substrate, it was heated at 90 ° C. for 90 seconds and cooled to room temperature (FIG. 1 (f)).

  Next, a second positive resist composition is applied on the substrate on which the first resist pattern 1b subjected to the above chemical treatment is formed, and baked at 110 ° C. for 60 seconds to obtain a film having a thickness of 80 nm. A second resist film 2 was formed (FIG. 1 (g)). At this time, the same 2nd resist composition as the 1st resist composition was used.

The wafer coated with the resist film 2 was subjected to immersion pattern exposure using an ArF excimer laser scanner (TWINSCAN XT: 1700Fi, manufactured by ASML) through an exposure mask m2 (line / space = 1/1) (FIG. 1 ( h)). Pure water was used as the immersion liquid, and the exposure amount was optimized to have a desired line width. Thereafter, the mixture was heated at 120 ° C. for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and spin-dried. Further, the remaining water was removed by heating at 90 ° C. for 90 seconds to obtain a second resist pattern 2a having a pitch of 100 nm and a line width of 50 nm (FIG. 1 (i)).
The obtained pattern was evaluated by the evaluation method described later, and the results are summarized in Table 5.

(Comparative Examples 1 and 2)
After the first resist pattern 1a was formed by the same method as in the above example, the following processing was performed. First, while rotating the substrate at 100 rpm, the processing agent FA (FB) is discharged from the nozzle n at a flow rate of 2 cc / sec at the center of the substrate for 5 seconds to form a paddle with a liquid temperature of 25 ° C. In this state, the substrate was allowed to stand for 90 seconds to bring the treatment agent into contact with the resist pattern. Thereafter, the treatment agent was spun off at 2000 rpm for 30 seconds.

Further, in order to remove the surplus treatment agent, the solvent (n-butanol) used for the treatment agent FA was discharged to the center of the substrate for 10 seconds at a flow rate of 1 ml / sec while rotating the substrate at 300 rpm. Thereafter, the substrate was rotated at 2000 rpm for 30 seconds to shake off the solvent. In order to remove the solvent remaining on the substrate, it was heated at 90 ° C. for 90 seconds and cooled to room temperature. As a result, a first resist pattern 1b subjected to the freezing treatment with the treating agent solution was obtained.
Subsequently, the 2nd resist pattern 2a was obtained by the method similar to the said Example.
The obtained pattern was evaluated by the following evaluation methods, and the results are summarized in Table 5.

〔Evaluation methods〕
(Evaluation of pattern line width)
In the resist pattern created by the above method, the line width (x [nm]) of the resist pattern 1a in FIG. 1C and the line width (y [nm]) of the resist pattern 1b in FIG. The line width variation before and after the formation of the second resist pattern in the first resist pattern was evaluated from the difference (y−x [nm]).

  The line width is measured using a length-measuring scanning electron microscope (SEM), and the pattern is observed. A length-measuring SEM (Hitachi, Ltd., S-9380II) is measured in the range where the edge in the longitudinal direction of the line pattern is 0.7 μm. ), The line width was measured at 50 points, and the average was calculated.

(LWR evaluation)
In the pattern 1b of FIG. 1 (f), the line pattern finished to 50 nm is observed with a scanning microscope (S9260 manufactured by Hitachi, Ltd.), and the range of the edge of 2 μm in the longitudinal direction of the line pattern is from the reference line where the edge should be The distance was measured at 50 points, the standard deviation was obtained, and 3σ was calculated. Similarly, in the pattern 1b of FIG. 1 (i), the standard deviation was similarly obtained and 3σ was calculated. Table 5 shows the result of subtracting 3σ of pattern 1b of FIG. 1 (i) from 3σ of pattern 1b of FIG. 1 (f). In addition, it shows that it is so favorable that a numerical value is small.

  From Table 5, it can be seen that according to the present invention, in the freezing process in the double patterning method, the line width variation of the first resist pattern is suppressed, and a pattern with good line edge roughness can be obtained.

The schematic process drawing explaining the pattern formation method used in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st resist film, 2 ... 2nd resist film, 3 ... Surface treatment agent (freezing agent), 4 ... Antireflection film, 5 ... Silicon wafer, 10 ... Surface treatment agent film, 1a ... first resist pattern, 1b ... first resist pattern (freezing treatment completed), 2a ... second resist pattern, m1, m2 ... mask, n ···nozzle

Claims (9)

A surface treatment agent for forming a resist pattern, comprising: (A) a compound having an epoxy skeleton or an oxetane skeleton; and (B) a compound or a resin or an oligomer inert to the resist pattern. The surface treatment agent for forming a resist pattern according to claim 1, wherein the compound (A) having an epoxy skeleton or an oxetane skeleton has a structure represented by the following general formula (i).

In general formula (i):
R ₁ represents a monovalent organic group.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.
when p is 2 or more, plural R ₁ may be the same or different, it may be bonded to each other to form a ring. The surface treatment agent for forming a resist pattern according to claim 2, wherein the compound (A) having a structure represented by the general formula (i) is represented by the following general formula (I).

In formula (I):
m represents an integer of 1 or more.
R ₁ represents a monovalent organic group.
R ₂ represents an m-valent organic group.
R ₁ and R ₂ may combine with each other to form a ring.
n represents 0 or 1.
p represents an integer of 2n + 3 or less.
when p is 2 or more, plural R ₁ may be the same or different, it may be bonded to each other to form a ring.   The surface treatment agent for forming a resist pattern according to claim 2, wherein the compound (A) is a resin or an oligomer having a group represented by the general formula (i) in the side chain.   The resist pattern according to any one of claims 1 to 4, wherein the resin or oligomer (B) inert to the compound (A) and the resist pattern is polyalkylene oxide or polyvinyl alcohol. Surface treatment agent for forming.   The resist pattern according to any one of claims 1 to 5, further comprising at least one organic solvent selected from an alcohol solvent, a fluorocarbon solvent, and a saturated hydrocarbon solvent. Surface treatment agent for forming.   A pattern that forms a first resist pattern on the first resist film, then forms a second resist film on the first resist pattern, and forms a second resist pattern on the second resist film The forming step is used for the first resist pattern after the first resist pattern is formed and before the second resist film is formed. Surface treatment agent for resist pattern formation. Forming a first resist pattern using the first resist composition;
A step of treating the first resist pattern with the surface treating agent according to any one of claims 1 to 7;
Forming a second resist pattern using a second resist composition on the first resist pattern after the surface treatment;
A resist pattern forming method comprising:   A heating step is included after the step of surface-treating the first resist pattern using the surface treating agent according to any one of claims 1 to 7, and before the step of forming the second resist pattern. The method for forming a resist pattern according to claim 8.

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