JP2010230891A - Radiation-sensitive resin composition, method for forming resist pattern, and block copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which can be suitably used for immersion exposure, wherein an obtained pattern feature is proper, an amount of an eluted component into a liquid for immersion exposure such as water which is brought into contact, with the composition during immersion exposure being small, a receding contact angle between a resist coating film and a liquid for immersion exposure such as water, being large and there are few development defects. <P>SOLUTION: The radiation-sensitive resin composition contains (A) an acid dissociable group-containing resin, (B) a radiation-sensitive acid generator, (C) a block copolymer having a fluorine atom, and (D) a solvent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition, a resist pattern forming method, and a block copolymer, and more specifically, to a liquid for immersion exposure such as water that has a good pattern shape and is in contact during immersion exposure. Radiation-sensitive resin composition that can be suitably used for immersion exposure, in which the amount of eluate is small, the receding contact angle between the resist coating and the immersion exposure liquid such as water is large, and there are few development defects The present invention relates to a resist pattern forming method capable of forming a resist pattern having a fine line width with few development defects, and a block copolymer having high solubility in a developing solution.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, recently, lithography technology capable of microfabrication at a level of 0.10 μm or less is required.

  However, in the conventional lithography process, near ultraviolet rays such as i rays are generally used as radiation, and it is said that fine processing at the subquarter micron level is extremely difficult with this near ultraviolet rays.

  Therefore, in order to enable fine processing at a level of 0.10 μm or less, use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include an emission line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, X-rays, and electron beams. Among these, KrF excimer laser (wavelength 248 nm) or ArF excimer laser (wavelength 193 nm) has attracted attention.

  As a resist suitable for irradiation with such an excimer laser, a component having an acid dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter also referred to as “exposure”) (hereinafter referred to as “acid generator”) Many resists using the chemical amplification effect (hereinafter also referred to as “chemically amplified resist”) have been proposed.

  As the chemically amplified resist, for example, a resist containing a resin having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and an acid generator has been proposed. In this resist, a t-butyl ester group or t-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, and the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposed region of the resist film becomes readily soluble in an alkali developer is utilized.

  In such a lithography process, further fine pattern formation (for example, a fine resist pattern having a line width of about 90 nm) will be required in the future. In order to achieve such a pattern formation with a line width finer than 90 nm, it is conceivable to shorten the light source wavelength of the exposure apparatus as described above and increase the numerical aperture (NA) of the lens.

  However, shortening the light source wavelength requires a new exposure apparatus, increasing the equipment cost. Further, when the lens has a high NA, the resolution and the depth of focus are in a trade-off relationship. Therefore, there is a problem that the depth of focus decreases even if the resolution is increased.

  In recent years, a liquid immersion lithography (liquid immersion lithography) method has been reported as a lithography technique that can solve such problems. In this method, a liquid refractive index medium (immersion exposure liquid) such as pure water or a fluorine-based inert liquid having a predetermined thickness is formed on at least the resist film between the lens and the resist film on the substrate during exposure. It is a method of interposing.

  In this method, a light source having the same exposure wavelength is used by replacing the exposure optical path space, which has conventionally been an inert gas such as air or nitrogen, with a liquid having a higher refractive index (n), such as pure water. However, as in the case of using a light source having a shorter wavelength or the case of using a high NA lens, high resolution is achieved. Further, there is no problem that the depth of focus is lowered as in the case of using a high NA lens. By using such an immersion exposure method, it is possible to realize formation of a resist pattern that is low in cost, excellent in resolution, and excellent in depth of focus using a lens mounted on an existing apparatus. . Currently, various resist polymers and additives for use in such immersion exposure are disclosed (see, for example, Patent Documents 1 to 3).

International Publication No. 04/068242 Pamphlet JP 2005-173474 A JP 2006-48029 A

  However, in the above-described immersion exposure process, since the resist film usually comes into direct contact with an immersion exposure liquid such as water during exposure, the acid generator and the like are eluted from the resist film. When the amount of the eluted material is large, there are problems that the lens is damaged, a predetermined pattern shape cannot be obtained, and sufficient resolution cannot be obtained.

  Also, when water is used as the liquid for immersion exposure, if the receding contact angle of water in the resist film is small, the liquid for immersion exposure such as water may spill from the edge of the wafer during high-speed scan exposure, or the water may run out. The water mark (droplet mark) remains due to the poorness of the film (watermark defect) or the water penetration into the resist film reduces the solubility of the film, and the pattern shape that should be resolved is locally sufficient. There is a problem in that resolution cannot be realized, and development defects such as unmelted defects that cause defective pattern shapes occur.

  Furthermore, even with resists using resins and additives as disclosed in Patent Documents 1 to 3, the receding contact angle between the resist film and water is not always sufficient, and the edge of the wafer during high-speed scanning exposure In some cases, liquid for immersion exposure such as water spills out and development defects such as watermark defects occur. Moreover, suppression of the amount of the eluate in water, such as an acid generator, was not enough.

  The present invention has been made in view of such problems of the prior art, and the problem is that the obtained pattern shape is good and immersion exposure of water or the like that is in contact with the immersion exposure. Radiation sensitivity that can be suitably used for immersion exposure with a small amount of eluate in the liquid for use, a large receding contact angle between the resist coating and liquid for immersion exposure such as water, and few development defects The object is to provide a resin composition. Moreover, the place made into the subject is providing the resist pattern formation method which can form a resist pattern with few development defects and a fine line | wire width. Furthermore, the place made into the subject is providing the block copolymer with the high solubility with respect to a developing solution.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors can achieve the above-mentioned problems by incorporating a block copolymer having a predetermined property having a fluorine atom into the radiation-sensitive resin composition. As a result, the present invention has been completed.

  That is, according to the present invention, the following radiation sensitive resin composition, resist pattern forming method, and block copolymer are provided.

  [1] A radiation sensitive composition comprising (A) an acid dissociable group-containing resin, (B) a radiation sensitive acid generator, (C) a block copolymer having a fluorine atom, and (D) a solvent. Resin composition.

  [2] The (C) block copolymer includes a first polymer block having a fluorine content of 0 to 15% by mass and a second polymer having a fluorine content of 20 to 50% by mass. The radiation-sensitive resin composition according to [1], including a block.

  [3] The radiation-sensitive resin composition according to [1] or [2], wherein the (C) block copolymer is a polymer having a (meth) acryl skeleton in its main chain.

  [4] The first polymer block has a structural unit represented by the following general formula (1-1), and the second polymer block is represented by the following general formula (1-2). The radiation-sensitive resin composition according to the above [2] or [3] having a structural unit.

（前記一般式（１−１）中、Ｒ^１は、水素原子、メチル基、又はトリフルオロメチル基を示し、Ｒ^２は、相互に独立に、炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示すか（但し、Ｒ^２の少なくとも１つは炭素数４〜２０の１価の脂環式炭化水素基又はその誘導体を示す）、或いは、何れか２つのＲ^２が相互に結合して、それぞれが結合している炭素原子とともに炭素数４〜２０の２価の脂環式炭化水素基又はその誘導体を形成し、残りのＲ^２が炭素数１〜４の直鎖状若しくは分岐状のアルキル基、又は炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体を示す。）

(In the general formula (1-1), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 2} are independently of each other, a monovalent alicyclic having 4 to 20 carbon atoms A hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ² is a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms) A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof, together with any carbon atoms to which any two R ² are bonded to each other. The remaining R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

（前記一般式（１−２）中、Ｒ^１は、水素原子、メチル基、又はトリフルオロメチル基を示し、Ｒ^３は、１〜１２個のフッ素原子を有する炭素数１〜２０の１価の直鎖状炭化水素基、分岐鎖状炭化水素基、若しくは脂環式炭化水素基を示すか、又は下記一般式（２）で表される１価の有機基を示す。）

In (Formula (1-2), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 3} is a monovalent C 1 -C 20 carbons having from 1 to 12 fluorine atoms A linear hydrocarbon group, a branched hydrocarbon group, or an alicyclic hydrocarbon group, or a monovalent organic group represented by the following general formula (2).

（前記一般式（２）中、Ｒ^４は、炭素数１〜１０の２価の直鎖状、分岐状、又は環状の飽和又は不飽和の炭化水素基を示し、Ｒ^５は、フッ素原子で置換された炭素数１〜１０の２価の直鎖状又は分岐状の炭化水素基を示し、Ｒ^６は、−ＯＸ^１を示す（但し、Ｘ^１は、水素原子又は酸で脱保護可能な１価の有機基を示す。）。）

(In the general formula (2), R ⁴ represents a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ represents a fluorine atom. Represents a substituted divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ represents —OX ¹ (provided that X ¹ can be deprotected with a hydrogen atom or an acid) Represents a monovalent organic group.).)

  [5] The above [1] to [4], wherein the content of the (C) block copolymer is 0.5 to 10 parts by mass with respect to 100 parts by mass of the (A) acid dissociable group-containing resin. The radiation-sensitive resin composition according to any one of the above.

  [6] The radiation-sensitive resin composition according to any one of [1] to [5], wherein the (C) block copolymer is obtained by living anionic polymerization.

  [7] (1) A step of forming a photoresist film on a substrate using the radiation sensitive resin composition according to any one of [1] to [6], and (2) on the photoresist film. Disposing an immersion exposure liquid and exposing the photoresist film through the immersion exposure liquid; (3) developing the exposed photoresist film to form a resist pattern; A resist pattern forming method comprising:

  [8] A first polymer block having a structural unit represented by the following general formula (1-1), and a second polymer block having a structural unit represented by the following general formula (1-2): A block copolymer having a polystyrene-reduced weight average molecular weight (Mw) of 1000 to 50000 as measured by gel permeation chromatography.

（前記一般式（１−１）中、Ｒ^１は、水素原子、メチル基、又はトリフルオロメチル基を示し、Ｒ^２は、相互に独立に、炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体、又は炭素数１〜４の直鎖状若しくは分岐状のアルキル基を示すか（但し、Ｒ^２の少なくとも１つは炭素数４〜２０の１価の脂環式炭化水素基又はその誘導体を示す）、或いは、何れか２つのＲ^２が相互に結合して、それぞれが結合している炭素原子とともに炭素数４〜２０の２価の脂環式炭化水素基又はその誘導体を形成し、残りのＲ^２が炭素数１〜４の直鎖状若しくは分岐状のアルキル基、又は炭素数４〜２０の１価の脂環式炭化水素基若しくはその誘導体を示す。）

(In the general formula (1-1), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 2} are independently of each other, a monovalent alicyclic having 4 to 20 carbon atoms A hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ² is a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms) A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof, together with any carbon atoms to which any two R ² are bonded to each other. The remaining R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

（前記一般式（１−２）中、Ｒ^１は、水素原子、メチル基、又はトリフルオロメチル基を示し、Ｒ^３は、１〜１２個のフッ素原子を有する炭素数１〜２０の１価の直鎖状炭化水素基、分岐鎖状炭化水素基、若しくは脂環式炭化水素基を示すか、又は下記一般式（２）で表される１価の有機基を示す。）

In (Formula (1-2), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 3} is a monovalent C 1 -C 20 carbons having from 1 to 12 fluorine atoms A linear hydrocarbon group, a branched hydrocarbon group, or an alicyclic hydrocarbon group, or a monovalent organic group represented by the following general formula (2).

（前記一般式（２）中、Ｒ^４は、炭素数１〜１０の２価の直鎖状、分岐状、又は環状の飽和又は不飽和の炭化水素基を示し、Ｒ^５は、フッ素原子で置換された炭素数１〜１０の２価の直鎖状又は分岐状の炭化水素基を示し、Ｒ^６は、−ＯＸ^１を示す（但し、Ｘ^１は、水素原子又は酸で脱保護可能な１価の有機基を示す。）。）

(In the general formula (2), R ⁴ represents a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ represents a fluorine atom. Represents a substituted divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ represents —OX ¹ (provided that X ¹ can be deprotected with a hydrogen atom or an acid) Represents a monovalent organic group.).)

  [9] The block copolymer according to [8], wherein the content ratio of the first polymer block is 5 to 95 mol%, and the content ratio of the second polymer block is 5 to 50 mol%.

  [10] The block copolymer according to [8] or [9], which is obtained by living anionic polymerization.

  The radiation-sensitive resin composition of the present invention has uniform fluorine content and protection rate of all molecules, so that the deprotection unevenness is reduced, and a resin having a low deprotection rate is not applied to the resist coating during development. Defects (blob-type defects) due to redeposition on the exposure region can be suppressed. Further, since each unit is a polymer block, the interaction of the fluorine unit is reduced, and the solubility in the developer after deprotection may be greatly improved. In addition, the deprotection efficiency is increased due to the reduced interaction of the fluorine unit. Further, since (C) purification of the block copolymer is unnecessary (no monomer cut is required), the molecular weight can be lowered (in radical polymerization, purification is usually difficult when the molecular weight is lowered).

  Therefore, the radiation-sensitive resin composition of the present invention has a good pattern shape, has a small amount of eluate in the liquid for immersion exposure such as water contacted during immersion exposure, resist film and water, etc. The liquid has a large receding contact angle with the liquid for immersion exposure and few development defects, and can be suitably used for immersion exposure. Further, according to the resist pattern forming method of the present invention, it is possible to form a resist pattern having a fine line width with few development defects. Furthermore, the block copolymer of the present invention has an effect of high solubility in a developer.

It is sectional drawing which shows an example of the state which made the photoresist film contact the ultrapure water.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that modifications, improvements, and the like appropriately added to the embodiments described above fall within the scope of the present invention.

I. Radiation Sensitive Resin Composition The radiation sensitive resin composition of the present invention comprises (A) an acid dissociable group-containing resin and (B) a radiation sensitive acid generator (hereinafter referred to as “(B) acid generator”). ), (C) a block copolymer having a fluorine atom (hereinafter, also referred to as “(C) block copolymer”), and (D) a solvent.

  The receding contact angle of the resist film made of the radiation sensitive resin composition of the present invention is preferably 70 ° or more, more preferably 72 ° or more, and particularly preferably 75 ° or more. Since the resist film comprising the radiation-sensitive resin composition of the present invention has such a high receding contact angle, the amount of eluate in the immersion exposure liquid such as water that has been contacted during immersion exposure is small, and development is performed. Since there are few defects, it can be suitably used for immersion exposure. In this specification, “retreat contact angle” means the liquid level when water of 25 μL is dropped on a substrate on which a coating film (resist coating) is formed and then water on the substrate is sucked at a rate of 10 μL / min. And the contact angle between the substrate and the substrate. Such a receding contact angle can be measured using, for example, a contact angle meter (trade name “DSA-10”) manufactured by KRUS. The radiation-sensitive resin composition of the present invention has a particularly excellent effect when the immersion exposure method is used, but can also be used in a normal resist pattern forming method that is not immersion exposure.

1 (A) Acid-dissociable group-containing resin (A) Acid-dissociable group-containing resin is a resin having an acid-dissociable group, and the effect of containing (C) a block copolymer in the radiation-sensitive resin composition, For example, there is no particular limitation as long as it has a large receding contact angle, a small amount of low molecular weight components are eluted, and an effect such as suppression of development defects can be suitably expressed. It is preferable to use an alkali-insoluble or hardly alkali-soluble polymer. “Alkali insoluble or hardly soluble in alkali” means (A) alkali development employed when a resist pattern is formed from a resist film formed from a radiation-sensitive resin composition containing an acid-dissociable group-containing resin. Under the conditions, when a film using only (A) an acid-dissociable group-containing resin is developed instead of the resist film, 50% or more of the initial film thickness of the film remains after development. In addition, the radiation sensitive resin composition of this invention may contain such (A) acid dissociable group containing resin individually by 1 type or in combination of 2 or more types.

(1) Component (A) Examples of the acid-dissociable group-containing resin include a “polymer having an alicyclic skeleton such as a norbornane ring in the main chain” obtained by polymerizing a norbornene derivative and the like, a norbornene derivative and anhydrous “Polymer having norbornane ring and maleic anhydride derivative in the main chain” obtained by copolymerization of maleic acid, “polymer having norbornane ring and (meth) acrylic compound in the main chain” ) "Polymer with mixed acrylic skeleton", obtained by copolymerization of norbornene derivative, maleic anhydride and (meth) acrylic compound "Heavy chain containing norbornane ring, maleic anhydride derivative and (meth) acrylic skeleton And “polymers having a (meth) acrylic skeleton in the main chain” obtained by polymerizing (meth) acrylic compounds. Among these, “a polymer having a (meth) acryl skeleton in the main chain” is more preferable.

  (A) The acid-dissociable group-containing resin has a structural unit having an acid-dissociable group. As such a structural unit, a structural unit represented by general formula (1-1) (hereinafter, also referred to as “structural unit (1)”) can be given. In addition, (A) acid dissociable group containing resin may have structural unit (1) individually by 1 type or in combination of 2 or more types.

In General Formula (1-1), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ² is independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms. A group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ² is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or Or any two R ² 's bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the carbon atom to which each R ² is bonded. And the remaining R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

Among the groups represented by R ² in general formula (1-1), examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms include cyclobutane, cyclopentane, cyclohexane, and bicyclo [2.2.1. ] Heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 . There are hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane and tricyclo [3.3.1.1 ^3,7 ] decane.

  Moreover, this alicyclic hydrocarbon group is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and at least one hydrogen atom in the above-mentioned unsubstituted alicyclic hydrocarbon group. , S-butyl group, i-butyl group, t-butyl group, etc., linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, hydroxyl group, cyano group, hydroxyalkyl group having 1 to 10 carbon atoms In addition, a derivative substituted with one or more of a carboxyl group, an oxygen atom and the like may be used.

  The content ratio of the structural unit (1) is preferably 10 to 70 mol%, more preferably 15 to 60 mol%, based on 100 mol% of all structural units constituting the (A) acid-dissociable group-containing resin. Preferably, it is 20-50 mol%, and it is especially preferable. There exists a possibility that the resolution as a resist may fall that a content rate is less than 10 mol%. On the other hand, if it exceeds 70 mol%, the exposure margin may be deteriorated.

  (A) The acid dissociable group-containing resin further preferably has a structural unit having a lactone skeleton (hereinafter also referred to as “structural unit (3)”). In addition, (A) acid dissociable group containing resin may have a structural unit (3) individually by 1 type or in combination of 2 or more types.

  Preferable examples of the monomer that gives the structural unit (3) include monomers represented by general formulas (3-1) to (3-6).

In general formulas (3-1) to (3-6), R ⁷ represents a hydrogen atom or a methyl group. In General Formula (3-1), R ⁸ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 4 carbon atoms, and l represents an integer of 1 to 3. In general formulas (3-2) and (3-3), A represents a single bond or a methylene group, and m represents 0 or 1. In general formulas (3-3) and (3-5), B represents an oxygen atom or a methylene group. In general formulas (3-4) and (3-5), R ⁹ represents a hydrogen atom or a methoxy group.

  The content ratio of the structural unit (3) is preferably 5 to 85 mol%, more preferably 10 to 70 mol%, based on 100 mol% of all structural units constituting the (A) acid-dissociable group-containing resin. It is especially preferable that it is 15-60 mol%. When the content ratio is less than 5 mol%, developability and exposure margin tend to be deteriorated. On the other hand, when it exceeds 85 mol%, the solubility and resolution of the (A) acid dissociable group-containing resin in the solvent (D) tend to deteriorate.

(2) Preparation method (A) The acid-dissociable group-containing resin includes, for example, a polymerizable unsaturated monomer corresponding to each structural unit, hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds Can be prepared by polymerizing in a suitable solvent in the presence of a chain transfer agent, if necessary.

  (A) As a solvent used for superposition | polymerization of acid dissociable group containing resin, Alkanes, such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; Cycloalkanes such as cycloheptane, cyclooctane, decalin and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene; halogenation such as chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide and chlorobenzene Hydrocarbons; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; Tetrahydrofuran, dimethoxyethane, diethoxyethane, etc. There is ether, and the like. In addition, these solvents can be used individually by 1 type or in combination of 2 or more types.

  (A) The reaction temperature in the polymerization of the acid dissociable group-containing resin is preferably 40 to 150 ° C, and more preferably 50 to 120 ° C. The reaction time at the time of polymerization is preferably 1 to 48 hours, and more preferably 1 to 24 hours.

(3) Physical Properties (A) The polystyrene-reduced weight average molecular weight (hereinafter also referred to as “Mw”) measured by gel permeation chromatography (GPC) of the acid-dissociable group-containing resin is not particularly limited, but is 1,000 to 100,000. It is preferable that it is 1000-30000, and it is especially preferable that it is 1000-20000. If it is less than 1000, the heat resistance of the resist tends to decrease. On the other hand, if it exceeds 100,000, the developability of the resist tends to be lowered. The ratio (Mw / Mn) of (A) the acid-dissociable group-containing resin Mw and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) measured by GPC is 1 to 5. Is preferable, and it is still more preferable that it is 1-3.

  Furthermore, the content ratio of the low molecular weight component derived from the monomer used when preparing the (A) acid-dissociable group-containing resin is in terms of solid content with respect to 100% by mass of the (A) acid-dissociable group-containing resin. It is preferably 0.1% by mass or less, more preferably 0.07% by mass or less, and particularly preferably 0.05% by mass or less. When the content ratio of the low molecular weight component is 0.1% by mass or less, it is possible to reduce the amount of the eluate in the immersion exposure liquid such as water that has been in contact with the immersion exposure. In addition, it is possible to suppress the generation of foreign matter in the resist during resist storage and the occurrence of coating unevenness during resist application, and the occurrence of defects during resist pattern formation can be sufficiently suppressed. The “monomer-derived low molecular weight component” includes a monomer, a dimer, a trimer, and an oligomer, and more specifically, a component having an Mw of 500 or less. Moreover, this low molecular weight component can be analyzed by high performance liquid chromatography (HPLC).

  Moreover, (A) acid dissociable group containing resin is so preferable that there are few impurities, such as a halogen and a metal. By reducing the impurities, it is possible to further improve the sensitivity, resolution, process stability, pattern shape, and the like of the resist.

  Low molecular weight components derived from monomers and impurities such as halogens and metals include, for example, chemical purification methods such as washing with water and liquid-liquid extraction, and physical purification such as these chemical purification methods and ultrafiltration and centrifugation. It can be removed by a combination with the law.

2 (B) Radiation-sensitive acid generator (B) The acid generator is a component that generates an acid upon exposure. The radiation-sensitive resin composition of the present invention contains (B) an acid generator, so that (A) an acid-dissociable group present in the acid-dissociable group-containing resin is formed by the action of an acid generated by exposure. The resist film is dissociated (the protecting group is eliminated). As a result, the exposed portion of the resist film becomes readily soluble in an alkali developer, and has a function of forming a positive resist pattern.

  As such (B) acid generator, what contains the compound represented by General formula (4) is preferable.

In the general formula (4), R ¹⁰ is a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched alkoxyl having 1 to 10 carbon atoms. A straight chain or branched alkoxycarbonyl group having 2 to 11 carbon atoms. R ¹¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxyl group having 1 to 10 carbon atoms, or a linear, branched or branched group having 1 to 10 carbon atoms. A cyclic alkanesulfonyl group is shown. R ¹² represents each independently a linear or branched alkyl group having 1 to 10 carbon atoms, an optionally substituted phenyl group, or an optionally substituted naphthyl group, or two R ¹² represents a divalent group having 2 to 10 carbon atoms which may be substituted, formed by bonding to each other. k represents an integer of 0 to 2, r represents an integer of 0 to 10, and Z ⁻ represents an anion represented by the following general formula (5).

R ¹³ C _q F _2q SO ₃ ⁻ (5)
(In General Formula (5), R ¹³ represents a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, and q represents an integer of 1 to 10)

Of the groups represented by R ^{10 to} R ¹² in the general formula (4), examples of the linear or branched alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, and an n-propyl group. I-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group , 2-ethylhexyl group, n-nonyl group, n-decyl group and the like. Among these, a methyl group, an ethyl group, an n-butyl group, and a t-butyl group are preferable.

Among the groups represented by R ¹⁰ and R ¹¹ in the general formula (4), examples of the linear or branched alkoxyl group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, and an n-propoxy group. I-propoxy group, n-butoxy group, 2-methylpropoxy group, 1-methylpropoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group, n-heptyloxy group N-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group and the like. Among these, a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group are preferable.

Of the groups represented by R ¹⁰ in the general formula (4), examples of the linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, and n-propoxycarbonyl. Group, i-propoxycarbonyl group, n-butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, t-butoxycarbonyl group, n-pentyloxycarbonyl group, neopentyloxycarbonyl group, n-hexyl Examples include an oxycarbonyl group, an n-heptyloxycarbonyl group, an n-octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, an n-nonyloxycarbonyl group, and an n-decyloxycarbonyl group. Among these, a methoxycarbonyl group, an ethoxycarbonyl group, and an n-butoxycarbonyl group are preferable.

Of the groups represented by R ¹¹ in the general formula (4), examples of the linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms include a methanesulfonyl group, an ethanesulfonyl group, and n- Propanesulfonyl group, n-butanesulfonyl group, tert-butanesulfonyl group, n-pentanesulfonyl group, neopentanesulfonyl group, n-hexanesulfonyl group, n-heptanesulfonyl group, n-octanesulfonyl group, 2-ethylhexanesulfonyl Group, n-nonanesulfonyl group, n-decanesulfonyl group, cyclopentanesulfonyl group, cyclohexanesulfonyl group and the like. Among these, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, and a cyclohexanesulfonyl group are preferable.

Of the groups represented by R ¹² in the general formula (4), examples of the optionally substituted phenyl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, 2, 3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,4,4 A phenyl group such as 6-trimethylphenyl group, 4-ethylphenyl group, 4-t-butylphenyl group, 4-cyclohexylphenyl group, 4-fluorophenyl group, linear, branched or A phenyl group substituted with a cyclic alkyl group; these phenyl group or alkyl-substituted phenyl group can be converted into a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxyl group, an alkoxy group; Examples include groups substituted with one or more groups such as a sialkyl group, an alkoxycarbonyl group, and an alkoxycarbonyloxy group.

  Among the groups substituted on the phenyl group or the alkyl-substituted phenyl group, examples of the alkoxyl group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, 1- Examples thereof include a linear, branched or cyclic alkoxyl group having 1 to 20 carbon atoms such as a methylpropoxy group, a t-butoxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

  Examples of the alkoxyalkyl group include a straight chain having 2 to 21 carbon atoms such as a methoxymethyl group, an ethoxymethyl group, a 1-methoxyethyl group, a 2-methoxyethyl group, a 1-ethoxyethyl group, and a 2-ethoxyethyl group. Examples include chain, branched or cyclic alkoxyalkyl groups.

  Furthermore, examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2-methylpropoxycarbonyl group, a 1-methylpropoxycarbonyl group, Examples thereof include a linear, branched or cyclic alkoxycarbonyl group having 2 to 21 carbon atoms such as a t-butoxycarbonyl group, a cyclopentyloxycarbonyl group, and a cyclohexyloxycarbonyl group.

  Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i-propoxycarbonyloxy group, n-butoxycarbonyloxy group, t-butoxycarbonyloxy group, and cyclopentyl. Examples thereof include linear, branched or cyclic alkoxycarbonyloxy groups having 2 to 21 carbon atoms such as oxycarbonyloxy group and cyclohexyloxycarbonyloxy group.

  Among the above-mentioned phenyl groups which may be substituted, a phenyl group, 4-cyclohexylphenyl group, 4-t-butylphenyl group, 4-methoxyphenyl group and 4-t-butoxyphenyl group are preferable.

Of the groups represented by R ¹² in the general formula (4), examples of the optionally substituted naphthyl group include 1-naphthyl group, 2-methyl-1-naphthyl group, 3-methyl-1- Naphthyl group, 4-methyl-1-naphthyl group, 5-methyl-1-naphthyl group, 6-methyl-1-naphthyl group, 7-methyl-1-naphthyl group, 8-methyl-1-naphthyl group, 2, 3-dimethyl-1-naphthyl group, 2,4-dimethyl-1-naphthyl group, 2,5-dimethyl-1-naphthyl group, 2,6-dimethyl-1-naphthyl group, 2,7-dimethyl-1- Naphthyl group, 2,8-dimethyl-1-naphthyl group, 3,4-dimethyl-1-naphthyl group, 3,5-dimethyl-1-naphthyl group, 3,6-dimethyl-1-naphthyl group, 3,7 -Dimethyl-1-naphthyl group, 3,8-dimethyl-1 -Naphthyl group, 4,5-dimethyl-1-naphthyl group, 5,8-dimethyl-1-naphthyl group, 4-ethyl-1-naphthyl group, 2-naphthyl group, 1-methyl-2-naphthyl group, 3 A naphthyl group substituted with a naphthyl group such as methyl-2-naphthyl group or 4-methyl-2-naphthyl group or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms; these naphthyl groups Alternatively, there are groups in which one or more alkyl-substituted naphthyl groups are substituted with groups such as hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, alkoxycarbonyloxy group, and the like.

  Of the groups substituted with a naphthyl group or an alkyl-substituted naphthyl group, the alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group, and alkoxycarbonyloxy group are exemplified as the group substituted with the above-described phenyl group or alkyl-substituted phenyl group. There is a group.

  Among the optionally substituted naphthyl groups described above, 1-naphthyl group, 1- (4-methoxynaphthyl) group, 1- (4-ethoxynaphthyl) group, 1- (4-n-propoxynaphthyl) group, 1- (4-n-butoxynaphthyl) group, 2- (7-methoxynaphthyl) group, 2- (7-ethoxynaphthyl) group, 2- (7-n-propoxynaphthyl) group, 2- (7-n -Butoxynaphthyl) group is preferred.

In the general formula (4), the divalent group having 2 to 10 carbon atoms formed by bonding two R ¹² to each other includes a 5- or 6-membered ring together with the sulfur cation in the general formula (4). A group that forms a 5-membered ring (that is, a tetrahydrothiophene ring) is more preferable.

  In addition, examples of the group that is substituted with a divalent group having 2 to 10 carbon atoms include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, exemplified as a group that is substituted with the above-described phenyl group or alkyl-substituted phenyl group, Examples include alkoxyl groups, alkoxyalkyl groups, alkoxycarbonyl groups, and alkoxycarbonyloxy groups.

In that have been described above also, the general formula (4) a group represented as R ¹² in the methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, 1-naphthyl group, or two R ¹² are bonded to each other It is preferable that the divalent group forms a tetrahydrothiophene ring structure together with the sulfur cation formed.

  In general formula (4), it is preferable that r is an integer of 0-2.

In the general formula (4), the C _q F _2q group in the anion represented by the general formula (5), which is a group represented by Z ⁻ , is a perfluoroalkylene group having a carbon number q. The fluoroalkylene group may be linear or branched. In general formula (5), q is preferably 1, 2, 4 or 8.

Among the groups represented by R ¹³ in general formula (5), the optionally substituted hydrocarbon group having 1 to 12 carbon atoms includes an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, and a bridged bridge. An alicyclic hydrocarbon group is preferred. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group N-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, norbornyl group, norbornylmethyl group, hydroxynorbornyl group, adamantyl Groups and the like.

  Preferred specific examples of the compound represented by the general formula (4) include triphenylsulfonium trifluoromethanesulfonate, tri-tert-butylphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium trifluoromethanesulfonate, and 4-methanesulfonylphenyl. -Diphenylsulfonium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium trifluoromethanesulfonate,

  Triphenylsulfonium perfluoro-n-butanesulfonate, tri-tert-butylphenylsulfonium perfluoro-n-butanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-butanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-butanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-butanesulfonate,

  Triphenylsulfonium perfluoro-n-octane sulfonate, tri-tert-butylphenylsulfonium perfluoro-n-octane sulfonate, 4-cyclohexylphenyl-diphenylsulfonium perfluoro-n-octane sulfonate, 4-methanesulfonylphenyl-diphenylsulfonium per Fluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro- n-octane sulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2 .1] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl)- 1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1,2,2-tetrafluoro Ethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (bicyclo [2.2. ] Hepta-2'-yl) -1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1,2,2-tetrafluoroethanesulfonate,

  Triphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, tri-tert-butylphenylsulfonium 2- (bicyclo [2.2.1] hepta-2 '-Yl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyl-diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 4-methanesulfonylphenyl -Diphenylsulfonium 2- (bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- ( Bicyclo [2.2.1] hepta-2'-yl) -1,1-difluoroeta Sulfonate, 1- (4-n- butoxynaphthyl) tetrahydrothiophenium 2- (bicyclo [2.2.1] hept-2'-yl) -1,1-difluoroethanesulfonate, and the like.

  In addition, (B) acid generator may contain the compound represented by General formula (4) individually by 1 type or in combination of 2 or more types.

  The content of (B) the acid generator is preferably 5 to 30 parts by mass, more preferably 5 to 25 parts by mass with respect to 100 parts by mass of the (A) acid-dissociable group-containing resin. It is particularly preferably 5 to 20 parts by mass. If the content is less than 5 parts by mass, the pattern may not be resolved or pattern collapse may occur. On the other hand, if it exceeds 30 parts by mass, the pattern may not be resolved or scum may be generated in the exposed area.

3 (C) Block copolymer (C) The block copolymer is a block copolymer having a fluorine atom. The radiation-sensitive resin composition of the present invention contains such a (C) block copolymer, so that a liquid for immersion exposure (for example, water) having a higher refractive index at a wavelength of 193 nm than that of air is used as a lens. In the resist pattern forming method including immersion exposure in which radiation is irradiated between the resist film and the resist film, the resist film can be particularly preferably used for forming the resist film. The resist film formed from this radiation-sensitive resin composition has a good pattern shape and has a small amount of eluate in the immersion exposure liquid such as water that has been in contact with the immersion exposure. And a liquid for immersion exposure such as water have a large receding contact angle (high receding contact angle), and there are few development defects.

(1) Component (C) The block copolymer has a first polymer block whose fluorine content is 0 to 15% by mass and a second polymer whose fluorine content is 20 to 50% by mass. A block copolymer containing a combined block is preferable. In addition, the (C) block copolymer may contain a 1st polymer block and a 2nd polymer block individually by 1 type or in combination of 2 or more types, respectively.

(First polymer block)
The first polymer block is a polymer block having a fluorine content of 0 to 15% by mass. Moreover, it is preferable to have the structural unit (1) described in “(A) Acid-dissociable group-containing resin”.

  Furthermore, it is more preferable to have a structural unit represented by the general formula (1-3) as the first polymer block.

In General Formula (1-3), R ¹⁴ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ¹⁵ is independently a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms. Or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ¹⁵ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or shows the derivatives thereof), or any two R ¹⁵ are bonded to each other, form a divalent alicyclic hydrocarbon group or a derivative thereof having 4 to 20 carbon atoms together with the carbon atom to which each is attached And the remaining R ¹⁵ represents a linear or branched alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.

Of the groups represented by R ¹⁵ in the general formula (1-3), examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms include cyclobutane, cyclopentane, cyclohexane, and bicyclo [2.2.1]. ] Heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 . There are hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane and tricyclo [3.3.1.1 ^3,7 ] decane.

  Moreover, this alicyclic hydrocarbon group is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and at least one hydrogen atom in the above-mentioned unsubstituted alicyclic hydrocarbon group. , S-butyl group, i-butyl group, t-butyl group, etc., linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, hydroxyl group, cyano group, hydroxyalkyl group having 1 to 10 carbon atoms In addition, a derivative substituted with one or more of a carboxyl group, an oxygen atom and the like may be used.

  The content ratio of the first polymer block is preferably 5 to 95 mol%, more preferably 30 to 90 mol%, based on 100 mol% of all structural units of the (C) block copolymer, and 50 It is especially preferable that it is -85 mol%. By adopting such a content ratio, both a sufficiently large receding contact angle and lithography performance can be achieved.

(Second polymer block)
The second polymer block is a polymer block having a fluorine content of 20 to 50% by mass. Moreover, it is preferable to have a structural unit represented by General Formula (1-2). The monomer constituting the first polymer block and the monomer constituting the second polymer block may be the same as long as the fluorine content of the polymer block is controlled within the respective ranges. Well, it can be different.

In General Formula (1-2), R ¹ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ³ represents a monovalent straight chain having 1 to 12 fluorine atoms and having 1 to 20 carbon atoms. A chain hydrocarbon group, a branched chain hydrocarbon group, an alicyclic hydrocarbon group, or a monovalent organic group represented by the general formula (2) is shown.

In the general formula (2), R ⁴ represents a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ is substituted with a fluorine atom. And a divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, wherein R ⁶ represents —OX ¹ (where X ¹ is a monovalent deprotectable with a hydrogen atom or an acid). Represents an organic group of

In general formula (1-2), the group represented by R ³ is a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-propyl group, a heptafluoro-i-propyl group, or a nonafluoro-n-butyl group. And a nonafluoro-i-butyl group, a nonafluoro-s-butyl group, and a nonafluoro-t-butyl group.

In general formula (2), the group represented by R ⁵ represents a linear or branched fluoroalkylene group having 1 to 10 carbon atoms. Preferable examples include fluoroalkylene groups as shown in the following formulas (X-1) to (X-8). Among these, a ditrifluoromethylmethylene group (that is, (X-1)) is particularly preferable.

In the general formula (2), a group represented as ^-R 5 -R ⁶ is preferably a group represented by the following formula (5-1) to (5-3).

  The content ratio of the second polymer block is preferably 5 to 50 mol%, more preferably 10 to 40 mol%, based on 100 mol% of all the structural units of the (C) block copolymer, 15 It is especially preferable that it is -30 mol%. If the content is less than 5 mol%, a sufficiently large receding contact angle may not be obtained. On the other hand, if it exceeds 50 mol%, there is a possibility that a good pattern shape cannot be obtained due to insufficient solubility of the (C) block copolymer in the developer.

  Moreover, the (C) block copolymer may further have other polymer blocks in addition to the first polymer block and the second polymer block.

  Examples of such other polymer blocks include (i) a polymer block having a lactone skeleton, a hydroxyl group, a carboxyl group, etc. capable of enhancing alkali solubility, and (ii) suppressing reflection from the substrate. Polymer block having aromatic hydrocarbon group or derivative thereof, (iii) aromatic hydrocarbon group or derivative thereof capable of enhancing etching resistance, polymer block having alicyclic hydrocarbon group or derivative thereof, etc. There is. Among these other polymer blocks, a polymer block having a lactone skeleton and a polymer block having an alicyclic hydrocarbon group or a derivative thereof are preferable.

  Examples of a preferable monomer that gives a polymer block having a lactone skeleton include monomers (3-1) to (3-6) described in “(A) Acid-dissociable group-containing resin”. .

  Moreover, as a polymer block which has an alicyclic hydrocarbon group or its derivative (s), specifically, the polymer block which has a structural unit represented by General formula (6) can be mentioned.

In General Formula (6), R ¹⁶ represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R ¹⁷ represents an alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

In the general formula (6), examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ¹⁷ include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2 2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tetracyclo [6.2.1.1 ^3,6 . Hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 ^2,7 ] dodecane and tricyclo [3.3.1.1 ^3,7 ] decane.

  Examples of the alicyclic hydrocarbon group derivative include, for example, at least one hydrogen atom in the above alicyclic hydrocarbon group, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl. Group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like, linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, hydroxyl group, cyano group, and 1 to 10 carbon atoms. Some are substituted with a hydroxyalkyl group, a carboxyl group, an oxygen atom or the like.

  In the radiation sensitive resin composition of the present invention, the content of the (C) block copolymer is 0.5 to 10 parts by mass with respect to 100 parts by mass of the (A) acid-dissociable group-containing resin. Preferably, it is 1-7 mass parts, More preferably, it is 1-5 mass parts. If the amount is less than 0.5 parts by mass, the water repellency of the surface may be insufficient, or the elution of the resist component into the immersion exposure liquid may not be suppressed. On the other hand, if it exceeds 10 parts by mass, the pattern may not be resolved or pattern collapse may occur.

(2) Preparation method (C) For example, the block copolymer is polymerized after the monomers constituting the first polymer block have been polymerized and the polymerization reaction has been completed, without any operations such as isolation. The monomer constituting the second polymer block can be charged and polymerized to carry out the polymerization. The polymerization method is not particularly limited, and can be performed by a conventionally known polymerization method such as radical polymerization, anionic polymerization, or cationic polymerization. Among these, it is preferable to carry out by anionic polymerization. Whether or not the polymerization reaction is completed can be confirmed, for example, by analyzing the polymerization solution by gas chromatography.

  Specific examples of the polymerization initiator used for anionic polymerization include alkyllithium such as n-butyllithium, sec-butyllithium and t-butyllithium, alkylenedilithium such as 1,4-dilithiobutane, and phenyl. Lithium, stilbene lithium, lithium naphthalene, sodium naphthalene, potassium naphthalene, n-butylmagnesium, n-hexylmagnesium, ethoxycalcium, calcium stearate, t-butoxystrontium, ethoxybarium, isopropoxybarium, ethylmercaptobarium, t-butoxybarium Phenoxybarium, diethylaminobarium, barium stearate and the like.

  (C) As a solvent used for the polymerization of the block copolymer, for example, alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cyclo Cycloalkanes such as heptane, cyclooctane, decalin, norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, chlorobenzene Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; tetrahydrofuran; Dimethoxyethane, diethoxyethane, etc. There is ether, and the like. In addition, these solvents can be used individually by 1 type or in combination of 2 or more types.

  (C) The reaction temperature in the polymerization of the block copolymer is preferably 40 to 150 ° C, and more preferably 50 to 120 ° C. The reaction time at the time of polymerization is preferably 1 to 48 hours, and more preferably 1 to 24 hours.

(3) Physical properties (C) The Mw of the block copolymer is preferably 1000 to 50000, more preferably 1000 to 20000, and particularly preferably 1000 to 10,000. If it is less than 1000, a sufficiently large receding contact angle may not be obtained. On the other hand, if it exceeds 50000, the developability when used as a resist tends to be lowered. In addition, the ratio (Mw / Mn) between Mw and Mn of the (C) block copolymer is preferably 1 to 1.2, and more preferably 1 to 1.1.

  In addition, (C) block copolymer is so preferable that there are few impurities, such as a halogen and a metal. By reducing the amount of impurities, it is possible to further improve the sensitivity, resolution, process stability, pattern shape, and the like of the resist.

4 (D) Solvent When the radiation sensitive resin composition of the present invention is used, the total solid content concentration is usually 1 to 50% by mass, preferably 1 to 25% by mass. Then, it is prepared and used as a composition solution by, for example, filtering with a filter having a pore size of about 0.05 μm.

  Examples of the solvent (D) include 2-butanone, 2-pentanone, 3-methyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-methyl-2-pentanone, and 3,3-dimethyl. Linear or branched ketones such as 2-butanone, 2-heptanone, 2-octanone; cyclopentanone, 3-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, 2,6-dimethylcyclohexanone, isophorone Cyclic ketones such as: 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 ether Propylene glycol monoalkyl ether acetates such as cetate, 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-ethoxypropionate Methyl phosphate, 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 Monoethyl ether, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, .gamma.-butyrolactone, ethylene carbonate, propylene carbonate and the like.

  Among these, linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and γ-butyrolactone are preferable. In addition, these (D) solvents can be used individually by 1 type or in mixture of 2 or more types.

5 (E) Nitrogen-containing compound The radiation-sensitive resin composition of the present invention may further contain (E) a nitrogen-containing compound as an additive. (E) The nitrogen-containing compound is a component having an action of controlling the diffusion phenomenon in the resist film of the acid generated from the (B) acid generator by exposure and suppressing undesirable chemical reaction in the non-exposed region. By containing such a nitrogen-containing compound (E), the storage stability of the resulting radiation-sensitive resin composition is improved. In addition, the resolution as a resist is further improved, and it is possible to suppress changes in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to post-exposure heat treatment, and the radiation sensitivity is extremely excellent in process stability. Resin composition can be obtained.

  Examples of (E) nitrogen-containing compounds include tertiary amine compounds, other amine compounds, amide group-containing compounds, urea compounds, and other nitrogen-containing heterocyclic compounds. In addition, (E) nitrogen-containing compound can be used individually by 1 type or in combination of 2 or more types.

  (E) The content of the nitrogen-containing compound is preferably 15 parts by mass or less with respect to a total of 100 parts by mass of (A) the acid dissociable group-containing resin and (C) the block copolymer, and 10 parts by mass. More preferably, it is more preferably 5 parts by mass or less. If it exceeds 15 parts by mass, the sensitivity as a resist tends to decrease. In addition, the lower limit of the content of the (E) nitrogen-containing compound is not particularly limited, but is usually 0.001 part by mass or more. If it is less than 0.001 part by mass, the pattern shape and dimensional fidelity as a resist may be lowered depending on the process conditions.

6 Other Additives The radiation sensitive resin composition of the present invention may further contain various other additives such as alicyclic additives, surfactants, and sensitizers as necessary. .

(Alicyclic additive)
An alicyclic additive is an additive that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a 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; t-butyl deoxycholic acid, t-butoxycarbonylmethyl deoxycholic acid, 2-ethoxyethyl deoxycholic acid, 2-deoxycholic acid 2- Cyclohexyloxyethyl, deoxy Deoxycholic acid esters such as 3-oxocyclohexyl cholic acid, tetrahydropyranyl deoxycholic acid, mevalonolactone ester of deoxycholic acid; t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, Lithocholic acid esters such as 2-cyclohexyloxyethyl lithocholic acid, 3-oxocyclohexyl lithocholic acid, tetrahydropyranyl lithocholic acid, mevalonolactone lithocholic acid; 3- (2-hydroxy-2,2-bis (trifluoromethyl) ) Ethyl) tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane and the like. In addition, these alicyclic additives can be used individually by 1 type or in combination of 2 or more types.

(Surfactant)
A surfactant is an additive that exhibits an effect of improving coatability, 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 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), Megafax F171, F173 (above, manufactured by Dainippon Ink and Chemicals), Florad FC430, FC431 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 ( As mentioned above, manufactured by Asahi Glass Co., Ltd.). In addition, these surfactants can be used individually by 1 type or in combination of 2 or more types.

(Sensitizer)
The sensitizer is an additive that acts to absorb the energy of radiation and transmit the energy to the acid generator (B), thereby increasing the amount of acid generated, and only the radiation-sensitive resin composition is applied. 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. In addition, these sensitizers can be used individually by 1 type or in combination of 2 or more types.

(Other)
In addition to the above-mentioned other additives, the radiation-sensitive resin composition of the present invention contains dyes or pigments to visualize the latent image in the exposed area, thereby reducing the influence of halation during exposure. can do. Moreover, adhesiveness with a board | substrate can be improved by containing an adhesion assistant. In addition, for example, an alkali-soluble resin, a low molecular weight alkali solubility controller having an acid-dissociable protecting group, an antihalation agent, a storage stabilizer, an antifoaming agent, dimethyl adipate, diethyl adipate, Alkylcarboxylic acid esters such as dipropyl adipate, di-n-butyl adipate, and di-t-butyl adipate may also be included.

II. Resist Pattern Forming Method The resist pattern forming method of the present invention is a step of forming a photoresist film on a substrate using the radiation sensitive resin composition described in (1) “I radiation sensitive resin composition”. And (2) a step of placing an immersion exposure liquid on the photoresist film and exposing the photoresist film through the immersion exposure liquid; and (3) developing the exposed photoresist film to form a resist. Forming a pattern. The radiation-sensitive resin composition is particularly useful as a chemically amplified resist. In the chemically amplified resist, (A) an acid-dissociable group-containing resin is produced by the action of an acid generated from (B) an acid generator upon exposure. The acid-dissociable group in the product dissociates to form a carboxyl group. As a result, the solubility of the exposed portion of the resist in the alkaline developer is increased, and this exposed portion is dissolved and removed by the alkaline developer. A resist pattern is obtained.

1 (1) Process To form a resist pattern using the radiation-sensitive resin composition of the present invention, first, a composition solution of the radiation-sensitive resin composition is applied by spin coating, cast coating, roll coating or the like. A photoresist film is formed by applying on a substrate such as a silicon wafer or a wafer covered with aluminum by an appropriate application means. In addition, you may heat-process (PB) after application | coating as needed.

  In order to maximize the potential of the radiation-sensitive resin composition of the present invention, use is made, for example, as disclosed in Japanese Patent Publication No. 6-12452 (Japanese Patent Laid-Open No. 59-93448). An organic or inorganic antireflection film may be formed on the substrate to be formed. In order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the photoresist film as disclosed in, for example, Japanese Patent Laid-Open No. 5-188598. Further, in order to prevent the (B) acid generator and the like from flowing out of the photoresist film in the immersion exposure, the immersion is performed on the photoresist film as disclosed in, for example, JP-A-2005-352384. A protective film can also be provided. These techniques can be used in combination.

2 (2) Step Next, the photoresist film is exposed through a mask so that a predetermined resist pattern is formed. In addition, immersion exposure liquid (liquid refractive index medium) such as pure water or fluorine-based inert liquid having a predetermined thickness is interposed between at least the photoresist film between the lens and the photoresist film on the substrate. . As the radiation used for the exposure, visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams, etc. can be appropriately selected and used according to the type of (B) acid generator, but an ArF excimer laser can be used. Far ultraviolet rays represented by (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser is more preferable.

  The exposure conditions such as the exposure amount are appropriately selected according to the blending composition of the radiation-sensitive resin composition, the type of additive, and the like. Note that heat treatment (hereinafter referred to as “PEB”) is preferably performed after exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the (A) acid dissociable group-containing resin proceeds smoothly. The heating conditions for this PEB vary depending on the composition of the radiation sensitive resin composition, but are preferably 30 to 200 ° C, more preferably 50 to 170 ° C.

3 (3) Process A predetermined resist pattern can be formed by developing the photoresist film exposed at the end with a developing solution.

  Examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [ 4.3.0] An alkaline aqueous solution in which at least one alkaline compound such as 5-nonene is dissolved is preferable. The concentration of the alkaline aqueous solution is preferably 10% by mass or less. If the concentration of the alkaline aqueous solution is more than 10% by mass, the unexposed area may be dissolved in the developer. In addition, after developing with the developing solution which consists of alkaline aqueous solution, generally it wash | cleans with water and dries.

  Moreover, an organic solvent can also be added to the developing solution which consists of alkaline aqueous solution. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, and 2,6-dimethylcyclohexanone; methanol, ethanol, n-propyl alcohol, i Alcohols such as propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol; ethers such as tetrahydrofuran and dioxane; ethyl acetate And esters such as n-butyl acetate and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; phenol, acetonylacetone and dimethylformamide. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types.

  It is preferable that the usage-amount of an organic solvent is 100 volume% or less with respect to 100 volume% of alkaline aqueous solution. If the amount of the organic solvent used is more than 100% by volume, the developability may be deteriorated, and the development residue in the exposed area may increase.

  Further, an appropriate amount of a surfactant or the like can be added to the developer composed of an alkaline aqueous solution.

III Block Copolymer The block copolymer of the present invention is described in “3 (C) Block Copolymer” in “I Radiation Sensitive Resin Composition” and is prepared by anionic polymerization. It is not necessary to remove the monomer, and its molecular weight can be lowered as compared with the case where it is prepared by radical polymerization. Therefore, the solubility with respect to a developing solution is high.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]: Gel permeation chromatography using monodisperse polystyrene as a standard under the following analysis conditions using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation. (GPC).
Flow rate: 1.0 mL / min Elution solvent: Tetrahydrofuran Column temperature: 40 ° C

  [Dispersity (Mw / Mn)]: Calculated from the measurement results.

[ ¹³ C-NMR analysis]: Measured using “JNM-EX270” manufactured by JEOL Ltd.

[Content ratio of monomer-derived low molecular weight component (%)]: High-performance liquid chromatography (HPLC) under the following analysis conditions using an “Intersil ODS-25 μm column” (4.6 mmφ × 250 mm) manufactured by GL Sciences Inc. It was measured by.
Flow rate: 1.0 mL / min Elution solvent: Acrylonitrile / 0.1% phosphoric acid aqueous solution

(Synthesis Example 1) (A) Preparation of Acid-Dissociable Group-Containing Resin (1) 11.93 g of a compound represented by the following formula (M-1) (hereinafter referred to as “monomer (M-1)”) 15 mol%), a compound represented by the following formula (M-2) (hereinafter referred to as “monomer (M-2)”) 39.60 g (35 mol%), and the following formula (M-3) 48.48 g (50 mol%) of a compound (hereinafter referred to as “monomer (M-3)”) is dissolved in 300 g of 2-butanone and further dimethyl 2,2′-azobisisobutyronitrile. A monomer solution was prepared by charging 58 g. A 500 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added using a dropping funnel. The solution was added dropwise over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C. or lower by water cooling. Next, the polymerization solution was poured into 2000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was washed twice on the slurry with 400 g of methanol, filtered again, and dried under reduced pressure at 60 ° C. for 15 hours to obtain a white powder polymer (74 g, yield). 74%). This polymer has Mw of 6900, Mw / Mn of 1.70, and from the measurement result of ¹³ C-NMR, the structural unit derived from the monomer (M-1), the monomer (M- The content ratio (mol%) of the structural unit derived from 2) and the structural unit derived from the monomer (M-3) was a copolymer of 14:37:49, respectively. This copolymer is referred to as (A) acid-dissociable group-containing resin (1). In addition, the content rate of the low molecular weight component derived from a monomer was 0.03% with respect to (A) acid dissociable group containing resin 100%.

Example 1 (C) Preparation of Block Copolymer (1) In a nitrogen atmosphere, in a solution of 5.1 g (0.12 mol) of lithium chloride dissolved in 1600 g of tetrahydrofuran (hereinafter referred to as “THF”), − After adding 21 g (0.050 mol) of the n-BuLi solution at 50 ° C., 9.113 g (0.050 mol) of 1-ethylcyclopentyl methacrylate was further added and stirred for 15 minutes. Subsequently, a solution obtained by dissolving 70.63 g (0.389 mol) of 1-ethylcyclopentyl methacrylate in 200 g of THF cooled to −50 ° C. was dropped. After completion of the dropwise addition, the mixture was further stirred for 90 minutes, and a small amount of the reaction solution was taken with a microsyringe, and it was confirmed by gas chromatography that there was no remaining 1-ethylcyclopentyl methacrylate. Subsequently, a solution obtained by dissolving 31.63 g (0.188 mol) of 2,2,2-trifluoroethyl methacrylate in 200 g of THF was added dropwise to the reaction solution. After completion of dropping, the mixture was further stirred for 60 minutes, and methanol was added to kill it. A small amount of this killing solution was taken and measured by gas chromatography, and it was confirmed that there was no 2,2,2-trifluoroethyl methacrylate remaining. The killing solution was poured into a large amount of water to precipitate a polymer, filtered, washed, and dried to obtain a white powdery polymer. The obtained polymer was dissolved again in THF and then poured into a large amount of methanol to precipitate the polymer. After filtration and washing, the polymer was dried under reduced pressure at 60 ° C. for 15 hours to obtain a white powdery polymer. This polymer has Mw of 4400, Mw / Mn of 1.06, a structural unit derived from monomer (M-1) from measurement of ¹³ C-NMR, and monomer (M-4) The content ratio (mol%) of the structural unit derived from was a copolymer of 68.8: 31.2, respectively. This copolymer is referred to as (C) block copolymer (1).

(Examples 2 and 3) (C) Preparation of block copolymers (2) and (3) A block (C) was prepared in the same manner as in Example 1 except that the polymerization reaction was carried out according to the formulation described in Table 1. Copolymers (2) and (3) were prepared. Table 1 shows the types of each monomer component, the blending amount (mol%) of the monomer component, the content ratio (mol%) of the structural unit derived from each monomer, and the values of Mw and Mw / Mn. Also shown.

(Example 4) (C) Preparation of block copolymer (4) After adding 21 g (0.050 mol) of n-BuLi solution at -50 ° C to 1600 g of THF under a nitrogen atmosphere, 1-ethylcyclopentyl was then added. 9.113 g (0.050 mol) of methacrylate was added and stirred for 15 minutes. Subsequently, a solution obtained by dissolving 70.63 g (0.389 mol) of 1-ethylcyclopentyl methacrylate in 200 g of THF cooled to −50 ° C. was dropped. After completion of the dropwise addition, the mixture was further stirred for 90 minutes, and a small amount of the reaction solution was taken with a microsyringe, and it was confirmed by gas chromatography that there was no remaining 1-ethylcyclopentyl methacrylate. Subsequently, a solution obtained by dissolving 31.63 g (0.188 mol) of 2,2,2-trifluoroethyl methacrylate in 200 g of THF was added dropwise to the reaction solution. After completion of dropping, the mixture was further stirred for 60 minutes, and methanol was added to kill it. A small amount of this killing solution was taken and measured by gas chromatography, and it was confirmed that there was no 2,2,2-trifluoroethyl methacrylate remaining. The killing solution was poured into a large amount of water to precipitate a polymer, filtered, washed, and dried to obtain a white powdery polymer. The obtained polymer was dissolved again in THF and then poured into a large amount of methanol to precipitate the polymer. After filtration and washing, the polymer was dried under reduced pressure at 60 ° C. for 15 hours to obtain a white powdery polymer. This polymer has Mw of 4300, Mw / Mn of 1.25, a structural unit derived from the monomer (M-1) from measurement of ¹³ C-NMR, and the monomer (M-4) The content ratio (mol%) of the structural unit derived from was a copolymer of 71.2: 28.8, respectively. This copolymer is referred to as (C) block copolymer (4).

  In addition, the kind of monomers other than the monomer (M-1)-(M-3) used in Examples 1-4 is described below.

(Comparative Example 1) (C) Preparation of copolymer (5) Monomer (M-1) 71.67 g (70 mol%) and monomer (M-4) 28.33 g (30 mol%) A monomer solution was prepared by dissolving in 100 g of 2-butanone and further adding 10.35 g of dimethyl 2,2′-azobisisobutyrate. A 500 mL three-necked flask charged with 100 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added using a dropping funnel. The solution was added dropwise over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization reaction, the polymerization solution was cooled to 30 ° C. or lower by water cooling. The polymerization solution was put into a mixed solution of 1200 g of methanol, 300 g of hexane and 60 g of water, stirred vigorously with a stirrer for 1 hour and allowed to stand for 2 hours, and then the lower layer was collected. After evaporating the solvent with an evaporator, 300 g of propylene glycol monomethyl ether acetate was added, and the concentration was measured using a refractometer. The solid content was 180 g (yield 60%). This polymer has Mw of 6000, Mw / Mn of 1.50, a structural unit derived from the monomer (M-1) from the measurement of ¹³ C-NMR, and the monomer (M-4 ) Was a copolymer having a content (mol%) of the structural unit derived from 70:30 respectively. This copolymer is referred to as (C) copolymer (5).

(Comparative example 2) (C) Preparation of copolymer (6) Monomer (M-1) 71.67 g (70 mol%) and monomer (M-4) 28.33 g (30 mol%) A solution was prepared by dissolving 0.72 g of dimethyl 2,2′-azobisisobutyrate and 2.1 g of 2-phenylpropan-2-ylbenzodithioate after dissolving in t-butylbenzene. This was stirred at 90 ° C. for 9 hours with stirring in a nitrogen atmosphere. After completion, the polymerization solution was allowed to cool to cool to 30 ° C. or lower. Thereafter, 7.47 g of dimethyl 2,2′-azobisisobutyrate was added to the polymerization solution, heated to 80 ° C., and stirred for 8 hours for end treatment. After the completion of the reaction, the solution was allowed to cool to 30 ° C. or lower, and then dropped into a mixed solvent of 1200 mL of methanol / water = 1/2 (mass ratio). The separated oily substance was recovered by decantation and dried at 40 ° C. for 12 hours to obtain the desired polymer. This polymer has Mw of 6000, Mw / Mn of 1.20, a structural unit derived from the monomer (M-1) from the measurement of ¹³ C-NMR, and the monomer (M-4 ) Was a copolymer having a content ratio (mol%) of 68.8: 31.2. This copolymer is referred to as (C) copolymer (6).

(Example 5)
100 parts of (A) acid-dissociable group-containing resin (1) prepared in Synthesis Example 1 and (B) 7 parts of triphenylsulfonium nonafluoro-n-butanesulfonate and 1- (4- n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate 2 parts, (C) block copolymer (1) prepared in Example 1, 5 parts, (D) propylene glycol monomethyl ether acetate 1330 as solvent Parts, 30 parts of γ-butyrolactone, 570 parts of cyclohexanone, and (E) 1.1 parts of Nt-butoxycarbonyl-4-hydroxypiperidine as a nitrogen-containing compound, and then filtered through a membrane filter having a pore size of 0.05 μm The composition solution 1 of the radiation sensitive resin composition was prepared.

(Examples 6-8, Comparative Examples 3-5)
Composition solutions 2 to 7 of the radiation sensitive resin composition were prepared in the same manner as in Example 5 except that it was prepared with the formulation described in Table 2.

  The compound names omitted in Table 2 are described below.

((B) acid generator)
(B-1): Triphenylsulfonium nonafluoro-n-butanesulfonate (B-2): 1- (4-n-butoxynaphthyl) tetrahydrothiophenium perfluoro-n-butanesulfonate

((D) solvent)
(D-1): Propylene glycol monomethyl ether acetate (D-2): γ-butyrolactone (D-3): Cyclohexanone

((E) Nitrogen-containing compound)
(E-1): Nt-butoxycarbonyl-4-hydroxypiperidine

  A positive resist pattern was formed using the composition solution of the prepared radiation-sensitive resin composition, and the radiation-sensitive resin composition was evaluated. The resist pattern formation method and its evaluation method are described below, and the results are shown in Table 3.

  [Formation of resist pattern]: A 12-inch silicon wafer having a 77 nm-thick lower-layer antireflection film (trade name “ARC29A”, manufactured by Brewer Science) on the surface was used as a substrate. This antireflection film was formed using a trade name “CLEAN TRACK ACT8” (manufactured by Tokyo Electron Ltd.). Subsequently, the radiation sensitive resin composition described in Table 3 was spin-coated on the substrate by CLEAN TRACK ACT8 and baked (PB) at 115 ° C. for 60 seconds to form a photoresist film having a thickness of 120 nm. Formed. An ArF excimer laser exposure apparatus (“NSR S306C”, manufactured by Nikon Corporation, illumination conditions; NA; 0.78, DipoleX, σ = 0.90 / 0.52) or an ArF excimer laser immersion exposure apparatus is applied to the photoresist film. (“NSR S610C”, manufactured by Nikon Corporation, illumination conditions; NA; 1.30, CrossPole, σ = 0.777 / 0.78), and exposed through a mask pattern. Thereafter, PEB was performed at 115 ° C. for 60 seconds, and then developed with a 2.38% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 30 seconds, washed with water, and dried to form a positive resist pattern.

[Recessed contact angle (°)]: Using “DSA-10” manufactured by KRUS, a substrate (wafer) on which a photoresist film formed of a radiation-sensitive resin composition was formed, and then promptly at room temperature; 23 ° C. , Humidity: 45%, measured under the normal pressure as follows.
1 Adjust the wafer stage position.
2 Set the wafer on the stage.
3 Inject water into the needle.
4 Finely adjust the needle position.
5 Drain water from the needle to form 25 μL water droplets on the wafer.
6 Pull the needle out of the water drop.
7 Pull the needle down again to the position adjusted in 4 above.
8 Aspirate a water droplet from the needle at a rate of 10 μL / min for 90 seconds. At the same time, the contact angle is measured every second (total 90 times).
9 From the time when the contact angle was stabilized, an average value was calculated for a total of 20 contact angles, and the average value was taken as the receding contact angle.

[Advance contact angle (°)]: Using “DSA-10” manufactured by KRUS, a substrate (wafer) on which a photoresist film made of a radiation-sensitive resin composition was formed, and immediately, room temperature; 23 ° C. , Humidity: 45%, measured under the normal pressure as follows.
1 Adjust the wafer stage position.
2 Set the wafer on the stage.
3 Inject water into the needle.
4 Finely adjust the needle position.
5 Drain water from the needle to form a 10 μL water droplet on the wafer.
6 Pull the needle out of the water drop.
7 Pull the needle down again to the position adjusted in 4 above.
Eject water droplets from the 8 needles at a rate of 10 μL / min for 90 seconds. At the same time, the contact angle is measured every second (total 90 times).
9 From the time when the contact angle was stabilized, an average value was calculated for a total of 20 contact angles, and the average value was taken as the forward contact angle.

[Static contact angle (°)] Using “DSA-10” manufactured by KRUS, a substrate (wafer) on which a photoresist film formed of a radiation-sensitive resin composition was formed, and then promptly at room temperature; 23 It measured as follows in 1 degreeC under the environmental conditions of (degreeC) and humidity; 45% and a normal pressure.
1 Adjust the wafer stage position.
2 Set the wafer on the stage.
3 Inject water into the needle.
4 Finely adjust the needle position.
5 Drain 0.5 μL of water from the needle to make a droplet at the tip of the needle.
6 Slowly lower the needle position and bring it closer to the wafer.
7 When the droplet approaches the wafer, the droplet moves to the wafer. At the same time, the contact angle is measured.
8 The operation from 1 to 7 was repeated 4 times, the average value was calculated, and the average value was taken as the static contact angle.

[Sensitivity (mJ / cm ² )]: The exposure amount for forming a line-and-space pattern (1L1S) having a line width of 90 nm in a one-to-one line width was defined as the optimum exposure amount, and this optimum exposure amount was defined as the sensitivity. A scanning electron microscope (“S-9380”, manufactured by Hitachi High-Technologies Corporation) was used for measuring the line width.

[Sensitivity (Immersion Exposure) (mJ / cm ² )]: The optimum exposure amount is defined as an exposure amount that forms a line-and-space pattern (1L1S) having a line width of 65 nm with a one-to-one line width. Was defined as sensitivity (immersion exposure). A scanning electron microscope (“CG-4000”, manufactured by Hitachi High-Technologies Corporation) was used for measuring the line width.

  [Blob defect number (development defect number)]: The entire surface of the wafer so that the exposed portion and unexposed portion of 1.5 cm square are in a checkered flag shape with the exposure amount of sensitivity (immersion exposure) on the resist-coated wafer. The pattern on the checkered flag was formed on the entire surface of the wafer by exposing the substrate and performing PEB and development. The number of defects on the unexposed portion of the wafer was measured using “KLA2351” manufactured by KLA-Tencor. The measured defects were observed using a scanning electron microscope (“CG-4000”, manufactured by Hitachi High-Technologies Corporation), blob-type defects were selected, and the number of defects is shown in Table 3.

  [Measurement of Elution Amount]: As shown in FIG. 1, an 8-inch silicon wafer that has been previously treated with hexamethyldisilazane 31 (100 ° C., 60 seconds) under the trade name “CLEAN TRACK ACT8” (manufactured by Tokyo Electron). A silicon rubber sheet 4 (manufactured by Kureha Elastomer Co., Ltd., thickness: 1.0 mm, shape: square with a side of 30 cm) was placed in the center of 3 above. Next, the hollowed portion at the center of the silicon rubber sheet 4 was filled with 10 mL of ultrapure water 5 using a 10 mL hole pipette.

  Separately, a lower layer antireflection film (trade name “ARC29A”, manufactured by Brewer Science Co., Ltd.) 61 having a film thickness of 77 nm is formed in advance by CLEAN TRACK ACT8, and then the radiation sensitive resin composition is formed in CLEAN TRACK ACT8. A silicon wafer 6 on which a 205 nm-thick photoresist film 62 was formed by spin coating on the antireflection film 61 and baking (115 ° C., 60 seconds) was prepared.

The prepared silicon wafer 6 is placed on the silicon rubber sheet 4 so that the photoresist film 62 is in contact with the ultrapure water 5 and the ultrapure water 5 is not leaked from the silicon rubber sheet 4. It was kept for 10 seconds. Thereafter, the silicon wafer 6 was removed, and the ultrapure water 5 was collected with a glass syringe, and this was used as a sample for analysis. The recovery rate of ultrapure water after the experiment was 95% or more. Subsequently, the peak intensity of the anion part of the acid generator (B) in the obtained ultrapure water was determined by LC-MS (liquid chromatograph mass spectrometer, LC part: SERIES1100 manufactured by AGILENT, MS part: Perseptive Biosystems, Inc. (Manufactured by Mariner) was measured under the following measurement conditions. At that time, (B) the peak intensities of 1ppb, 10ppb, and 100ppb aqueous solutions of the acid generator were measured under measurement conditions to prepare a calibration curve, and the elution amount was calculated from the peak intensity using this calibration curve. Similarly, each peak intensity of 1Eppb, 10ppb, and 100ppb aqueous solutions of (E) acid diffusion controller is measured under measurement conditions to create a calibration curve, and (E) acid is calculated from the peak intensity using this calibration curve. The elution amount of the diffusion control agent was calculated. The case where the elution amount was 5.0 × 10 ⁻¹² mol / cm ² / sec or more was evaluated as “bad”, and the case where it was 5.0 × 10 ⁻¹² mol / cm ² / sec or less was “good” ".

  As can be seen from Table 3, when the radiation-sensitive resin composition of the present invention is used, the receding contact angle between the resist film and water is large, and in immersion exposure, at the same level as when no fluororesin is contained. Since blob defects can be suppressed, it can be suitably used for immersion exposure. Moreover, the elution to the liquid for immersion exposure of low molecular weight components, such as (B) acid generator and (E) acid diffusion control agent, can be suppressed.

  If the radiation sensitive resin composition of the present invention is used, a fine pattern can be stably formed, and therefore it can be suitably used for semiconductor devices and the like that are expected to be further miniaturized in the future.

3, 6: silicon wafer, 4: silicon rubber sheet, 5: ultrapure water, 31: hexamethyldisilazane, 61: lower antireflection film, 62: photoresist film.

Claims (10)

(A) an acid dissociable group-containing resin;
(B) a radiation sensitive acid generator;
(C) a block copolymer having a fluorine atom;
(D) A radiation sensitive resin composition containing a solvent. The (C) block copolymer is
A first polymer block having a fluorine content of 0 to 15% by mass;
The radiation sensitive resin composition of Claim 1 containing the 2nd polymer block whose fluorine content rate is 20-50 mass%.   The radiation-sensitive resin composition according to claim 1 or 2, wherein the (C) block copolymer is a polymer having a (meth) acryl skeleton in its main chain. The first polymer block has a structural unit represented by the following general formula (1-1),
The radiation-sensitive resin composition according to claim 2 or 3, wherein the second polymer block has a structural unit represented by the following general formula (1-2).

(In the general formula (1-1), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 2} are independently of each other, a monovalent alicyclic having 4 to 20 carbon atoms A hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ² is a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms) A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof, together with any carbon atoms to which any two R ² are bonded to each other. The remaining R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

In (Formula (1-2), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 3} is a monovalent C 1 -C 20 carbons having from 1 to 12 fluorine atoms A linear hydrocarbon group, a branched hydrocarbon group, or an alicyclic hydrocarbon group, or a monovalent organic group represented by the following general formula (2).

(In the general formula (2), R ⁴ represents a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ represents a fluorine atom. Represents a substituted divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ represents —OX ¹ (provided that X ¹ can be deprotected with a hydrogen atom or an acid) Represents a monovalent organic group.).)   The content of the (C) block copolymer is 0.5 to 10 parts by mass with respect to 100 parts by mass of the (A) acid-dissociable group-containing resin. The radiation sensitive resin composition as described.   The radiation sensitive resin composition according to any one of claims 1 to 5, wherein the (C) block copolymer is obtained by living anionic polymerization. (1) forming a photoresist film on a substrate using the radiation sensitive resin composition according to any one of claims 1 to 6;
(2) arranging a liquid for immersion exposure on the photoresist film, and exposing the photoresist film through the liquid for immersion exposure;
(3) A step of developing the exposed photoresist film to form a resist pattern. A first polymer block having a structural unit represented by the following general formula (1-1);
A second polymer block having a structural unit represented by the following general formula (1-2), and a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography is 1000 to 50000 A block copolymer.

(In the general formula (1-1), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 2} are independently of each other, a monovalent alicyclic having 4 to 20 carbon atoms A hydrocarbon group or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms (provided that at least one of R ² is a monovalent alicyclic hydrocarbon having 4 to 20 carbon atoms) A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof, together with any carbon atoms to which any two R ² are bonded to each other. The remaining R ² represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

In (Formula (1-2), ^{R 1} represents a hydrogen atom, a methyl group, or trifluoromethyl group, ^{R 3} is a monovalent C 1 -C 20 carbons having from 1 to 12 fluorine atoms A linear hydrocarbon group, a branched hydrocarbon group, or an alicyclic hydrocarbon group, or a monovalent organic group represented by the following general formula (2).

(In the general formula (2), R ⁴ represents a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ represents a fluorine atom. Represents a substituted divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ represents —OX ¹ (provided that X ¹ can be deprotected with a hydrogen atom or an acid) Represents a monovalent organic group.).) The content ratio of the first polymer block is 5 to 95 mol%,
The block copolymer according to claim 8, wherein the content ratio of the second polymer block is 5 to 50 mol%.   The block copolymer according to claim 8 or 9, which is obtained by living anionic polymerization.

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