JP5696352B2 - Radiation sensitive resin composition and polymer used therefor - Google Patents

Description

  The present invention relates to a radiation-sensitive resin composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photolithography processes, a polymer suitably used for the composition, and the polymer. It relates to the compound used for.

  The chemically amplified radiation-sensitive resin composition generates an acid in an exposed area by irradiation with far ultraviolet light or the like typified by a KrF excimer laser or an ArF excimer laser. It is a composition that changes the dissolution rate of the unexposed portion with respect to the developer to form a resist pattern on the substrate.

  When more precise line width control is performed, for example, when the device design dimension is sub-half micron or less, the chemically amplified resist not only has excellent resolution performance but also resist pattern line. It has become important that LWR (Line Width Roughness), which is an index of variation in width, is small and the pattern shape is rectangular.

In order to control such a fine shape, a component having an acid dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter referred to as “exposure”) (hereinafter referred to as “acid generator”). Many resists that utilize the chemical amplification effect (hereinafter referred to as “chemically amplified resist”) have been proposed.
As this chemically amplified resist, for example, a resist containing a polymer having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and an acid generator has been proposed (see Patent Document 1). ). This resist is an acidic group in which a t-butoxycarbonyl group or a t-butyl carbonate group present in a polymer is dissociated by the action of an acid generated by exposure, and the polymer is composed of a carboxyl group or a phenolic hydroxyl group. As a result, it utilizes the phenomenon that the exposed region of the resist film becomes readily soluble in an alkaline developer.

  By the way, most of the conventional chemically amplified resists are based on phenolic polymers. However, in the case of such polymers, if far ultraviolet rays are used as radiation, it is caused by the aromatic ring in the polymer. Since far ultraviolet rays are absorbed, the exposed far ultraviolet rays cannot sufficiently reach the lower layer of the resist film. Therefore, the exposure amount is large in the upper layer part of the resist film and smaller in the lower layer part, and the pattern profile of the resist pattern after development is thin at the upper part and becomes a trapezoidal shape thicker toward the lower part, and sufficient resolution can be obtained. There was no problem. In addition, when the pattern profile after development has a trapezoidal shape, a desired dimensional accuracy cannot be achieved in the next process, that is, etching or ion implantation, which is a problem.

  On the other hand, the resist pattern shape can be improved by increasing the radiation transmittance of the resist film. For example, a (meth) acrylate polymer represented by polymethyl methacrylate is highly transparent to far ultraviolet rays and is a very preferable polymer from the viewpoint of radiation transmittance. For example, a methacrylate polymer is used. A chemically amplified resist has been proposed (see Patent Document 2). However, the LWR characteristics and pattern rectangularity are still insufficient.

JP 59-45439 A JP-A-4-226461 JP-A-7-234511

  An object of the present invention is to provide a radiation-sensitive resin composition capable of forming a resist pattern having a small LWR and an excellent pattern shape.

The radiation sensitive resin composition of the present invention is
(A) a polymer (hereinafter also referred to as “polymer (A)”) containing a repeating unit represented by the following general formula (1) (hereinafter also referred to as “repeating unit (1)”);
(B) a radiation-sensitive acid generator (hereinafter also referred to as “acid generator (B)”);
(C) An organic solvent (hereinafter also referred to as “solvent (C)”) is contained.

(In the formula, R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, R ⁴ represents an alkyl group having 1 to ⁴ carbon atoms, and X represents a linear or branched hydrocarbon having 1 to 10 carbon atoms. Group, or a group in which some or all of these hydrogen atoms are substituted with fluorine.)

  In the radiation-sensitive resin composition of the present invention, the polymer (A) preferably further has a repeating unit represented by the following formula (2) (hereinafter also referred to as “repeating unit (2)”).

(In the formula, ^{R 1} is the same .R ¹⁰ in the formula (1) is a monovalent alicyclic hydrocarbon group having an alkyl group or 4 to 20 carbon atoms having 1 to 4 carbon atoms, R ¹¹ mutually A carbon atom which is independently an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or two R ¹¹ 's bonded to each other, and both are bonded And a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.)

The polymer of the present invention is characterized by having a repeating unit (1).
The polymer of the present invention preferably further has a repeating unit (2).

  The compound of the present invention is represented by the following formula (i).

(In the formula, the definitions of R ¹ , R ⁴ and X are the same as in the above formula (1).)

The radiation sensitive resin composition of the present invention has an effect that a resist pattern having a small LWR and an excellent pattern shape can be formed.
The polymer and compound of the present invention are suitably used as a raw material for the radiation-sensitive resin composition of the present invention.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

<Polymer (A)>
The polymer (A) constituting the radiation-sensitive resin composition of the present invention is a polymer of the present invention, and has a repeating unit (1). The repeating unit (1) has a tertiary alkoxycarbonyl structure, and this structure is decomposed by an acid generated by the radiation sensitive acid generator (B) and subsequent baking. Thereby, as for the radiation sensitive resin composition containing a polymer (A), a developing solution solubility is provided to an exposed part, and the spreading | diffusion of the acid to an unexposed part is suppressed by the generated hydroxyl group. As a result, the contrast between exposed and unexposed is increased, and an excellent effect peculiar to the present application that particularly good LWR characteristics and pattern shapes can be obtained.

In the above formula (1), R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, preferably a hydrogen atom or a methyl group. R ⁴ represents an alkyl group having 1 to ⁴ carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and an n-butyl group. Of these, a methyl group is preferably used. X represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, or a group in which some or all of these hydrogen atoms are substituted with fluorine. For example, methylene group, ethylene group, n-propylene Group, i-propylene group, n-butylene group and the like. Of these, ethylene group, i-propylene group and the like are preferably used.

As the monomer used for obtaining the repeating unit (1), the compound of the present invention represented by the above formula (i) is used. Preferable specific examples of the compound include, for example, compounds represented by the following formulas (i-1) to (i-4). Of these, compounds in which R ¹ is a hydrogen atom or a methyl group are preferably used.

(Wherein R ¹ is as defined in the above formula (1).)

  As shown in the following formula (I), the compound of the present invention can be synthesized by reacting a compound such as hydroxyalkyl (meth) acrylate with a dialkyl dicarbonate having a quaternary carbon.

The polymer (A) is a polymer exhibiting alkali insolubility or alkali insolubility, and further has a second protective group (acid dissociable group) that can be removed by the action of acid, and the action of acid. The polymer is preferably a polymer exhibiting alkali solubility by elimination of the protecting group. As the repeating unit having the second acid-dissociable group, the repeating unit (2) is preferable.
In the formula (2), the alkyl group having 1 to 4 carbon atoms in ^{R 2} and ^{R 3,} methyl, ethyl, n- propyl, i- propyl, n- butyl, 2-methylpropyl group , 1-methylpropyl group, t-butyl group and the like. Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms in R ² and R ³ include a cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; Examples thereof include a group having a bridged alicyclic skeleton such as a pentanyl group, a dicyclopentenyl group, a tricyclodecyl group, a tetracyclododecyl group, and an adamantyl group. Further, as the divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms which is formed together with the carbon atom to which the two R ³ are bonded to each other, the above-described monovalent alicyclic hydrocarbon group may be used. A group obtained by removing one hydrogen atom from a hydrocarbon group can be exemplified.

  Preferred examples of the repeating unit (2) include the following formulas (2-1) to (2-9).

(In the formula, R ¹ has the same definition as the above formula (1).)

The polymer (A) may further have other repeating units. Preferably, it further contains a repeating unit having a lactone skeleton. Examples of the repeating unit having a lactone skeleton include (meth) acrylic acid-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid. -9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] non-2-yl ester, (meth) acrylic acid-5-oxo-4-oxa-tricyclo [ 5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid-10-methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] Non-2-yl ester, (meth) acrylic acid-6-oxo-7-oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-6-oxo −7− Xa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic Acid-4-methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] oct-2-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4-yl ester, (meth) Acrylic acid-4-methyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-propyl-2 -Oxotetrahydropyran-4-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2,2 -Dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-2-oxotetrahydrofuran-3-yl ester , (Meth) acrylic acid-4,4-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid 2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester , (Meth) acrylic acid-4,4-dimethyl-5-oxy And a repeating unit derived from compounds such as tetrahydrofuran-2-yl methyl ester.
Examples of other repeating units include other repeating units derived from (meth) acrylic acid esters, such as hydroxyl group-containing (meth) acrylic acid esters and carboxyl group-containing (meth) acrylic acid esters.

The ratio of the repeating unit (1) in the polymer (A) is preferably from 0.1 to 30 mol%, particularly preferably from 0.1 to 20 mol%, based on all repeating units. If this ratio is less than 0.1 mol%, effects such as pattern shape and LWR reduction may be insufficient. Moreover, when it exceeds 20 mol%, there exists a possibility that the problem of a shape defect by low sensitivity or lack of solubility may arise.
Further, the ratio of the repeating unit (2) is preferably 20 to 80 mol%, particularly preferably 25 to 75 mol% in all repeating units. If this ratio is less than 25 mol%, sufficient solubility may not be obtained and resolution may deteriorate. Moreover, when it exceeds 75 mol%, there exists a possibility that adhesiveness with a board | substrate may deteriorate.

<Method for producing polymer (A)>
The production method of the polymer (A) of the present invention is not particularly limited. For example, a polymerizable unsaturated monomer corresponding to each repeating unit constituting a desired molecular composition is converted into a radical polymerization initiator. If necessary, it can be produced by polymerization in an appropriate solvent in the presence of a chain transfer agent or the like. The radical polymerization initiator is preferably added so as to have a sufficiently high concentration in order to realize a sufficient polymerization rate. However, if the ratio of the amount of radical polymerization initiator to the amount of chain transfer agent is too high, a radical-radical coupling reaction will occur and an undesirable non-living radical polymer will be formed, so the resulting polymer will have a molecular weight and molecular weight distribution, etc. In other words, a portion having uncontrolled characteristics in the polymer characteristics is included. The molar ratio between the amount of radical polymerization initiator and the amount of chain transfer agent is preferably (1: 1) to (0.005: 1).

Although it does not specifically limit as said radical polymerization initiator, A thermal polymerization initiator, a redox polymerization initiator, and a photoinitiator are mentioned. Specific examples include polymerization initiators such as peroxides and azo compounds. More specific radical polymerization initiators include t-butyl hydroperoxide, t-butyl perbenzoate, benzoyl peroxide, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azo. Examples thereof include bisisobutyronitrile (AIBN), 1,1′-azobis (cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate (MAIB), and the like.
Examples of the chain transfer agent include pyrazole derivatives and alkylthiols.

  As for the polymerization operation, polymerization can be carried out by a usual method such as batch polymerization or dropping polymerization. For example, with respect to the monomer that forms each of the above repeating units (1) and (2) and other repeating units as required, the necessary types and amounts are dissolved in an organic solvent, and a radical polymerization initiator and chain transfer are dissolved. A polymer (A) is obtained by polymerizing in the presence of an agent. As the polymerization solvent, an organic solvent capable of dissolving the monomer, radical polymerization initiator and chain transfer agent is generally used. Examples of the organic solvent include ketone solvents, ether solvents, aprotic polar solvents, ester solvents, aromatic solvents, and linear or cyclic aliphatic solvents. Examples of the ketone solvent include methyl ethyl ketone and acetone. Examples of ether solvents include alkoxyalkyl ethers such as methoxymethyl ether, ethyl ether, tetrahydrofuran, and 1,4-dioxane. Examples of the aprotic polar solvent include dimethylformamide and dimethylsulfoxide. Examples of ester solvents include alkyl acetates such as ethyl acetate and methyl acetate. Aromatic solvents include alkylaryl solvents such as toluene, xylene, and halogenated aromatic solvents such as chlorobenzene. Examples of the aliphatic solvent include hexane and cyclohexane.

The polymerization temperature is generally 20 to 120 ° C, preferably 50 to 110 ° C, more preferably 60 to 100 ° C. Although polymerization may be performed even in a normal air atmosphere, polymerization in an inert gas atmosphere such as nitrogen or argon is preferable. The molecular weight of the polymer (A) can be adjusted by controlling the ratio between the monomer amount and the chain transfer agent amount. The polymerization time is generally 0.5 to 144 hours, preferably 1 to 72 hours, more preferably 2 to 24 hours.
The polymer (A) may have a residue derived from a chain transfer agent at the end of the molecular chain, may not have a residue derived from the chain transfer agent at the end of the molecular chain, It may be in a state in which a part of the residue derived from the chain transfer agent remains.
The polymer (A) is naturally low in impurities such as halogen and metal, but the residual monomer or oligomer component is preferably not more than a predetermined value, for example, 1% by mass or less by HPLC analysis. Thus, it is possible to obtain a radiation-sensitive resin composition that can be used as a resist that not only can further improve the sensitivity, resolution, process stability, pattern shape, and the like as a resist, but also has little change over time in foreign matter and sensitivity.

  Examples of the method for purifying the polymer (A) include the following methods. As a method for removing impurities such as metals, a method of adsorbing metals in the polymer (A) solution using a zeta potential filter, or washing the polymer (A) solution with an acidic aqueous solution such as oxalic acid or sulfonic acid. And a method of removing the metal in a chelated state. In addition, as a method of removing residual monomer and oligomer components below the specified value, liquid-liquid extraction method that removes residual monomer and oligomer components by combining water washing and an appropriate solvent, those with a specific molecular weight or less A residual monomer by coagulating the polymer (A) in the poor solvent by dripping the polymer (A) solution into the poor solvent by a purification method such as ultrafiltration for extracting and removing only the polymer There are a reprecipitation method for removing etc. and a purification method in a solid state such as washing the filtered polymer slurry with a poor solvent. Moreover, these methods can also be combined. The poor solvent used in the reprecipitation method depends on the physical properties of the polymer (A) to be purified and cannot be generally exemplified. However, those skilled in the art will appropriately select the poor solvent according to the physical properties of the polymer. can do.

The weight average molecular weight in terms of polystyrene (hereinafter abbreviated as “Mw”) by gel permeation chromatography (GPC) of the polymer (A) is usually 1,000 to 300,000, preferably 2,000 to 300,000. More preferably, it is 2,000-12,000. When the Mw of the polymer (A) is less than 1,000, the heat resistance as a resist tends to be lowered. On the other hand, when it exceeds 300,000, the developability as a resist tends to be lowered.
The ratio (Mw / Mn) of Mw of the polymer (A) to polystyrene-reduced number average molecular weight (hereinafter abbreviated as “Mn”) by gel permeation chromatography (GPC) is preferably 1 to 5, and more preferably Preferably it is 1-3, Most preferably, it is 1-1.6.

<Acid generator (B)>
The acid generator (B) used in the radiation-sensitive resin composition of the present invention is a substance that generates an acid upon irradiation with radiation.
A general thing can be used as this acid generator (B). For example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethane sulfonate, triphenylsulfonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate, tri Phenylsulfonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, triphenylsulfonium camphorsulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cycl Rohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1 , 1,2,2-tetrafluoroethane sulfonate, 4-cyclohexyl-phenyl diphenyl sulfonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate 4-cyclohexylphenyldiphenylsulfonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 4-cyclohexylphenyldiphenylsulfonium camphorsulfonate, 4-t-butylphenol Phenyldiphenylsulfonium trifluoromethanesulfonate, 4-t-butylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-t-butylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-t-butylphenyldiphenylsulfonium 2-bicyclo [2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-t-butylphenyldiphenylsulfonium 2- (3-tetracyclo [4.4.0.1 ^{2, 5.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate, 4-t-butylphenyl diphenyl sulfonium N, N-bis (nonafluoro -n- butanesulfonyl) imidate, 4-t-butylphenyl diphenyl sulfonyl Umcamphor sulfonate,

Tri (4-t-butylphenyl) sulfonium trifluoromethanesulfonate, tri (4-t-butylphenyl) sulfonium nonafluoro-n-butanesulfonate, tri (4-t-butylphenyl) sulfonium perfluoro-n-octanesulfonate, Tri (4-t-butylphenyl) sulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, tri (4-t-butylphenyl) sulfonium 2 - (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate, tri (4-t- butylphenyl) sulfonium N, N-bis (nonafluoro - n-butanesulfonyl) imidate, tri (4-t-butylphenyl) sulfo Nitrogen camphorsulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1, 1,2,2 tetrafluoroethane sulfonate, diphenyliodonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate, diphenyliodonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, diphenyliodonium camphorsulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis ( 4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2. 2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium 2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, bis (4-t- butylphenyl) iodonium N, N-bis (nonafluoro -n- butanesulfonyl) imidate, bis (4-t- butylphenyl) Iodonium camphorsulfonate,

1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (4-n-Butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2-bicyclo [2.2. 1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10 ] dodecanyl) -1,1-difluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiofe Nitrogen camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butane Sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [ 2.2.1] Hept- - yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (3-tetracyclo [4.4.0.1 ^{2, 5.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate,

1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophene Nium camphorsulfonate, N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2. 2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) succinimide, N- (2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10} ] dodecanyl) -1,1-difluoroethanesulfonyloxy) Succinimide, N- (camphorsulfonyloxy) succinimide, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyl) Oxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene- 2,3-dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept 5-ene-2,3-dicarboximide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1 -Difluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2, 3-dicarboximide or the like is preferably used.
These acid generators (B) may be used alone or in combination of two or more.

  The blending amount of the acid generator (B) is usually 0.1 to 20 parts by mass, preferably 0.1 to 100 parts by mass of the polymer (A) from the viewpoint of ensuring the sensitivity and developability as a resist. -10 parts by mass. When the amount is less than 0.1 part by mass, the sensitivity and developability may be reduced. On the other hand, when it exceeds 20 parts by mass, the transparency to radiation is lowered, and it may be difficult to obtain a rectangular resist pattern.

<Solvent (C)>
When the radiation-sensitive resin composition of the present invention is used, it is dissolved in a solvent so that the total solid content is usually 1 to 50% by mass, preferably 1 to 25% by mass. It is prepared as a composition solution by filtering with a filter of about 2 μm.

  Examples of the solvent (C) include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, 3,3- Linear or branched ketones such as dimethyl-2-butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, Cyclic ketones such as isophorone; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-i-propyl ether acetate, propylene glycol mono-n-butyl Propylene glycol monoalkyl ether acetates such as ether acetate, propylene glycol mono-i-butyl ether acetate, propylene glycol mono-sec-butyl ether acetate, propylene glycol mono-t-butyl ether acetate; methyl 2-hydroxypropionate, 2-hydroxypropionic acid Ethyl, 2-hydroxypropionate n-propyl, 2-hydroxypropionate i-propyl, 2-hydroxypropionate n-butyl, 2-hydroxypropionate i-butyl, 2-hydroxypropionate sec-butyl, 2-hydroxy Alkyl 2-hydroxypropionates such as t-butyl propionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxy Methyl propionate, other 3-alkoxy propionic acid alkyl such as ethyl 3-ethoxypropionate,

  n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclohexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether , Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, propylene glycol monomethyl ether , Propylene glycol monoethyl Ether, propylene glycol mono-n-propyl ether, toluene, xylene, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, Ethyl acetoacetate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol Cole monoethyl ether, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, etc. Can do.

Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable. .
These solvent (C) may be used independently and may be used in combination of 2 or more type.

<Additives>
In the radiation sensitive resin composition of the present invention, various additives such as an acid diffusion controller, an alicyclic additive, a surfactant, and a sensitizer are added as necessary unless the effects of the present invention are impaired. Can be blended.

(Acid diffusion control agent)
The acid diffusion controller is a component having an action of controlling a diffusion phenomenon in the resist film of an acid generated from an acid generator by exposure and suppressing an undesirable chemical reaction in a non-exposed region.
By blending such an acid diffusion controller, the storage stability of the resulting radiation-sensitive resin composition can be improved. In addition, the resolution of the resist can be further improved, and the change in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to post-exposure heat treatment can be suppressed, resulting in extremely high process stability. An excellent composition can be obtained.

Examples of the acid diffusion controller include nitrogen-containing compounds such as tertiary amine compounds, amide group-containing compounds, quaternary ammonium hydroxide compounds, and other nitrogen-containing heterocyclic compounds.
Examples of the tertiary amine compound include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n- Tri (cyclo) alkylamines such as octylamine, cyclohexyldimethylamine, dicyclohexylmethylamine, tricyclohexylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4- Aromatic amines such as methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline; alkanolamines such as triethanolamine, N, N-di (hydroxyethyl) aniline; N, N, N ′, N′-Tetramethylethyl Diamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, bis (2- Examples thereof include dimethylaminoethyl) ether and bis (2-diethylaminoethyl) ether.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-butoxy. Carbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-(- ) -1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonylpipe Gin, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′- Diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl-1 , 7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di- t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′- -T-butoxycarbonyl-4,4'-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, etc. Examples thereof include Nt-butoxycarbonyl group-containing amino compounds.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

Examples of the other nitrogen-containing heterocyclic compounds include: pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl- Pyridines such as 4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline and acridine; in addition to piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine, Pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2 ] Octane, imidazole, 4-methylimida 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenz Examples thereof include imidazole and Nt-butoxycarbonyl-2-phenylbenzimidazole.
These nitrogen-containing compounds may be used alone or in combination of two or more.

  The blending amount of the acid diffusion controller is usually 10 parts by mass or less, preferably 5 parts by mass or less with respect to 100 parts by mass of the resin (A) from the viewpoint of ensuring high sensitivity as a resist. When this compounding quantity exceeds 10 mass parts, there exists a possibility that the sensitivity as a resist may fall remarkably. In addition, when the compounding quantity of an acid diffusion control agent is less than 0.001 mass part, there exists a possibility that the pattern shape and dimension fidelity as a resist may fall depending on process conditions.

(Alicyclic additive)
The alicyclic additive is a low molecular component that has an effect of further improving dry etching resistance, pattern shape, adhesion to the substrate, and the like.
Examples of such alicyclic additives include 1-adamantanecarboxylic acid, 2-adamantanone, 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α. -Butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t-butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantane diacetate di-t-butyl, 2, Adamantane derivatives such as 5-dimethyl-2,5-di (adamantylcarbonyloxy) hexane; alkylcarboxyl such as dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-butyl adipate, di-t-butyl adipate Acid esters and 5- [2-hydroxy 2,2-bis (trifluoromethyl) ethyl] tetracyclo [6.2.1.1 ^{3, 6.} 0 ^2,7 ] dodecane and the like. Other compounds include deoxycholic acid t-butoxycarbonylmethyl ester and richolic acid t-butoxycarbonylmethyl ester. Etc.
These alicyclic additives may be used alone or in combination of two or more.

(Surfactant)
A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like.
Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, and polyethylene glycol dilaurate. In addition to nonionic surfactants such as polyethylene glycol distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (manufactured by Tochem Products Co., Ltd.), Megafax F171, F173 (manufactured by Dainippon Ink & Chemicals, Inc.), Florard FC430, FC431 ( Sumitomo 3M Limited), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-105, SC-106 (Asahi Glass Co., Ltd.) And the like.
These surfactants may be used alone or in combination of two or more.

(Sensitizer)
The sensitizer absorbs radiation energy and transmits the energy to the acid generator (B), thereby increasing the amount of acid generated. Has the effect of improving the sensitivity.
Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like.
These sensitizers may be used alone or in combination of two or more.

  Furthermore, the radiation-sensitive resin composition of the present invention includes, in addition to the above-mentioned additives, an alkali-soluble resin, a low-molecular alkali-solubility control agent having an acid-dissociable protecting group, and antihalation as necessary. An agent, a storage stabilizer, an antifoaming agent and the like can be blended. In addition, by blending a dye or pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be alleviated, and by blending an adhesion aid, adhesion to the substrate can be improved. it can.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, the part is based on mass unless otherwise specified.

Each measurement and evaluation in each of the following synthesis examples was performed in the following manner.
(1) Mw and Mn
Gel permeation based on monodisperse polystyrene using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation under the analysis conditions of flow rate 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C. It was measured by an association chromatography (GPC). Further, the degree of dispersion Mw / Mn was calculated from the measurement results.
(2) ¹³ C-NMR, ¹ H-NMR analysis ¹³ C-NMR analysis of each resin and ¹ H-NMR of the monomer were measured using “JNM-EX270” manufactured by JEOL Ltd.

Hereinafter, synthesis examples of the compound (monomer) represented by the following formula (M-5) will be described.
In a 300 mL two-necked flask, 6.51 g (50.0 mmol) of 2-hydroxyethyl methacrylate, 10.91 g (50.0 mmol) of di-tert-butyl dicarbonate, and 100 mL of dry THF were added and stirred for 5 minutes. 4-Methylaminopyridine (0.122 g, 1 mmol) was added and stirred at room temperature for 3 hours. Thereafter, the solution which was extracted three times with 100 mL of ethyl acetate and washed twice with 100 mL H ₂ O was removed with an evaporator, and then dried overnight at room temperature. Finally, it is isolated by silica gel column chromatography (developing solvent hexane: ethyl acetate = 1: 1), and the solution is removed with an evaporator to obtain 10.48 g (yield 97%) of the desired product (M-5). It was.

For the synthesized (M-5), the compound was identified by ¹ H-NMR. The peak intensity and chemical shift are shown below.
¹ H-NMR: 1.46 (s, 9H, CO (C H ₃ ) ₃ ), 1.92 (s, 3H, CH ₃ ), 4.34 (m, 4H, OC H ₂ C H ₂ O), 5.60 (s, 1H , C H ₂ = C), 6.13 (s, 1H, C H ₂ = C)

Hereinafter, each synthesis example of resin (A) is demonstrated.
Each monomer used for the synthesis | combination of resin (A) is shown below as a formula (M-1)-(M-5).

<Synthesis of Resin (A-1)>
12.87 g (50 mol%) of the monomer (M-1), 3.52 g (10 mol%) of the monomer (M-5), and 13.6 g (40 mol) of the monomer (M-3) %) Was dissolved in 60 g of 2-butanone, and a monomer solution into which 1.26 g (5 mol%) of azobisisobutyronitrile was further added was prepared. Thereafter, a 500 mL three-necked flask charged with 30 g of 2-butanone was purged with nitrogen for 30 minutes. After the nitrogen purge, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added dropwise over 3 hours using a dropping funnel. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After the completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or less, poured into 600 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice with 200 g of methanol as a slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (24 g, yield 80%). .
This copolymer had Mw of 6832, Mw / Mn of 1.660, and as a result of ¹³ C-NMR analysis and ¹ H-NMR analysis, it was found that compound (M-1), (M-5) and compound (M-3 ) Was a copolymer having a content of each repeating unit derived from 49.5: 10.2: 40.3 (mol%). This copolymer is referred to as “polymer (A-1)”.

<Synthesis of Resins (A-2) to (A-6)>
Resin (A) was synthesized by the same method as the synthesis of Resin (A-1) except that the monomers shown in Table 1 and the monomer having a mass of charge mol% were used and the methanol solvent was appropriately changed to a hexane solvent. -2) to (A-6) were synthesized. The obtained polymer was measured for Mw, Mw / Mn (molecular weight dispersity), yield (mass%), and the ratio (mol%) of each repeating unit in the polymer. The results are shown in Table 2.

<Preparation of radiation-sensitive resin composition>
The resin (A), the acid generator (B), the nitrogen-containing compound (D) and the solvent (C) are mixed at the ratio shown in Table 3, and the radiation sensitive resins of Examples 1 to 3 and Comparative Examples 1 to 3 are mixed. A composition was prepared.

Here, each detail of (B) acid generator, (C) solvent, and (D) acid diffusion control agent of Table 1 is demonstrated.
<(B) Acid generator>
B-1: Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate B-2: 4-cyclohexylphenyldiphenylsulfonium nonafluoro -N-butanesulfonate B-3: 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2- Tetrafluoroethanesulfonate <(C) Solvent>
C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexanone C-3: Gamma butyrolactone <(D) Acid diffusion controller>
D-1: Nt-butoxycarbonyl-4-hydroxypiperidine

<Evaluation of radiation-sensitive resin composition>
Various evaluation was performed as follows about each radiation sensitive resin composition of Examples 1-4 and Comparative Examples 1-4. These evaluation results are shown in Table 4.

<Sensitivity>
When exposure is performed with an ArF light source, a silicon wafer having an ARC29 (Nissan Chemical Industries Co., Ltd.) film having a film thickness of 770 mm is formed on the wafer surface, and each composition solution is placed on a substrate with a clean track ACT8 (manufactured by Tokyo Electron). ) Was applied by spin coating, and PB was performed on a hot plate under the conditions shown in Table 4 to form a resist film having a thickness of 0.09 μm. The resist film formed as described above was exposed through a mask pattern using a Nikon ArF excimer laser exposure apparatus “S306C” (numerical aperture 0.78). After performing PEB under the conditions shown in Table 4, it was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, washed with water, and dried to form a positive resist pattern. At this time, an exposure amount such that a line and space pattern (1L1S) having a diameter of 0.090 μm in the mask has a diameter of 0.090 μm was set as the optimum exposure amount, and this optimum exposure amount was set as the sensitivity.

<Cross-sectional shape of pattern (pattern shape)>
The cross-sectional shape of the 0.075 μm line-and-space pattern in the sensitivity measurement described above was observed with “S-4800” manufactured by Hitachi High-Technologies Corporation, indicating a T-top shape (ie, a shape other than a rectangle). The case was “bad”, and the case showing a rectangular shape was “good”.

<LWR (Line Widness Roughness)>
At the optimum exposure amount, the 0.090 μm (1L / 1S) pattern formed on the resist film on the substrate was observed from the top of the pattern using a length measurement SEM (manufactured by Hitachi, Ltd., model number “S9380”), The diameter is measured at an arbitrary point, and the measurement variation is expressed by 3 sigma.
In addition, this value is so preferable that it is small, and the case where it was 9.0 nm or less was made favorable.

Claims (3)

(A) a polymer containing a repeating unit represented by the following general formula (1) and a repeating unit represented by the following formula (2);
(B) a radiation sensitive acid generator;
(C) an organic solvent, and the blending amount of the (B) radiation-sensitive acid generator is 0.1 to 20 parts by mass with respect to 100 parts by mass of the (A) polymer. A radiation sensitive resin composition.

(Wherein R ¹ represents a hydrogen atom, a methyl group or a trifluoromethyl group, R ⁴ represents an alkyl group having 1 to ⁴ carbon atoms, X represents a methylene group, an ethylene group, an n-propylene group, i-propylene)
Group or n-butylene group . )

(In the formula, R ¹ is the same as the above formula (1). R ² is an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ³ is mutually A carbon atom which is independently an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or two R ³ 's bonded to each other, and both are bonded And a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.) The radiation sensitive resin composition of Claim 1 whose ratio of the repeating unit represented by the said Formula (2) in the said (A) polymer is 25-75 mol% in all the repeating units. A polymer having a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), wherein the repeating unit represented by the above formula (2) A polymer having a ratio of 25 to 75 mol% in all repeating units.