JP2010160346A - Radiation-sensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which has a large depth of focus and ensures small LWR and MEEF, excellent pattern collapse resistance and excellent development defect control property. <P>SOLUTION: The radiation-sensitive resin composition includes: a polymer (A) having one or more repeating units represented by general formulae (1) and (2) and one or more repeating units (3) having a carbonate structure; and a radiation-sensitive acid generator (B). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiation-sensitive resin composition used in semiconductor manufacturing processes such as ICs, circuit boards such as liquid crystals and thermal heads, and other photolithography processes. More specifically, a chemically amplified radiation-sensitive resin composition that can be suitably used in a photolithography process using far ultraviolet rays having a wavelength of 250 nm or less or an electron beam as an exposure light source, such as KrF excimer laser and ArF excimer laser. It is about.

  The chemically amplified radiation-sensitive resin composition generates an acid in an exposed portion by irradiation with far ultraviolet rays or electron beams typified by a KrF excimer laser or an ArF excimer laser, and is exposed by a chemical reaction using this acid as a catalyst. It is a composition that causes a difference in the dissolution rate of the part and the unexposed part in the developer to form a resist pattern on the substrate.

  For example, when a KrF excimer laser (wavelength 248 nm) is used as a light source, a polymer having a basic skeleton of poly (hydroxystyrene) (hereinafter sometimes referred to as “PHS”) that has low absorption in the 248 nm region. A chemically amplified radiation-sensitive resin composition containing as a constituent is used. According to this composition, high sensitivity, high resolution, and good pattern formation can be realized.

  However, when a shorter wavelength light source, for example, an ArF excimer laser (wavelength 193 nm) is used as a light source for the purpose of further microfabrication, an aromatic compound such as PHS having a large absorption in the 193 nm region should be used. There was a problem that was difficult.

  Therefore, as a lithography material using an ArF excimer laser as a light source, a polymer having an alicyclic hydrocarbon having no large absorption in the 193 nm region in its skeleton, particularly a polymer having a lactone skeleton in its repeating unit is constituted. A resin composition as a component is used.

  As the radiation sensitive resin composition as described above, for example, a radiation sensitive resin composition containing a polymer having a mevalonic lactone skeleton or a γ-butyrolactone skeleton in its repeating unit is disclosed. (See Patent Documents 1 and 2).

JP-A-9-73173 US Pat. No. 6,388,101

  It has been found that the above-mentioned composition has a lactone skeleton in its repeating unit, so that the resolution performance as a resist is remarkably improved. However, at the present time when the miniaturization of resist patterns has progressed to a level of 90 nm or less, not only high resolution performance but also other performance has been required. For example, as one of the resist pattern miniaturization techniques, liquid immersion exposure is currently being put into practical use, and a resist material that can cope with this liquid immersion exposure is demanded. Specifically, development of materials that satisfy various required characteristics such as LWR (Line Wide Logness), MEEF (Mask Error Enhanced Factor), pattern shape, exposure margin, depth of focus (DOF), etc. is required. ing.

  The present invention has been made in view of such problems of the prior art, and provides a radiation-sensitive resin composition having excellent LWR, MEEF, and pattern shape, and having excellent exposure margin and DOF. It is.

  As a result of intensive studies to solve the problems of the prior art as described above, the present inventors have sensitized a resin comprising a polymer having a repeating unit containing a cyclic carbonate structure and a radiation-sensitive acid generator. The present inventors have found that the above-mentioned problems can be solved by using the component of the radiation resin composition, and have completed the present invention. Specifically, the present invention provides the following radiation-sensitive resin composition.

[1] Polymer (A) containing at least one type of repeating unit represented by the following general formulas (1) and (2) and a repeating unit (3) having a cyclic carbonate structure, and a radiation-sensitive acid generator A radiation-sensitive resin composition containing (B).

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )
(In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, the general formula (1) (Excluding repeating units represented by

[2] A polymer containing at least one type of repeating unit represented by the following general formulas (1) and (2) and a repeating unit (3) having a cyclic carbonate structure.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )
(In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, the general formula (1) (Excluding repeating units represented by

  The radiation sensitive resin composition of this invention has favorable LWR, MEEF, and pattern shape. The radiation-sensitive resin composition of the present invention is further excellent in exposure margin and DOF. Therefore, it can be suitably used as a lithography material using an ArF excimer laser as a light source. Moreover, it can respond also to the lithography material which uses immersion exposure and a KrF excimer laser as a light source.

  Hereinafter, the best mode for carrying out the radiation-sensitive resin composition of the present invention will be specifically described. However, the present invention includes all embodiments including the invention-specific matters, and is not limited to the embodiments described below. In the following description, the same type of substituent is given the same reference numeral, and the description is omitted.

  Moreover, in this specification, "... group" shall mean "optionally substituted ... group". For example, when “alkyl group” is described, it includes not only an unsubstituted alkyl group but also an alkyl group in which a hydrogen atom is substituted with another functional group. Furthermore, “... group” means “optionally branched ... group”. For example, “alkylcarbonyl group” includes not only a linear alkylcarbonyl group but also a branched alkylcarbonyl group.

  The radiation-sensitive resin composition of the present invention comprises a polymer (A) and an acid generator (B) as essential components, and an acid diffusion inhibitor (C), a solvent (D) and an additive (E) depending on the purpose. ). Hereinafter, each component will be described.

[1] Polymer (A):
The polymer (A) in the present invention contains one or more types of repeating units represented by the following general formulas (1) and (2) and a repeating unit (3) having a carbonate structure.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )
(In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, the general formula (1) (Excluding repeating units represented by

[1-1] Repeating unit (1):
The polymer (A) is a polymer having a repeating unit of the following general formula (1).

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )

  As the repeating unit (1), repeating units represented by the following general formulas (1-1) to (1-18) are particularly preferable.

  In the polymer (A), one of the exemplified repeating units (1) may be contained alone, or two or more thereof may be contained. In the polymer (A), the content of the repeating unit (1) is preferably 5 to 80 mol%, more preferably 10 to 80 mol%, based on all repeating units constituting the polymer (A). It is further more preferable that it is 20 to 70%. If the content of the repeating unit (1) exceeds 80 mol%, the adhesiveness of the resist film is lowered, and pattern collapse or pattern peeling may occur.

[1-2] Repeating unit (2):
The polymer (A) is a polymer having a repeating unit of the following general formula (2).

(In the general formula (2), R ³ represents hydrogen or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, it is represented by the general formula (1). (Excluding repeating units.)

In the general formula (2), as the “alkyl group having 1 to 20 carbon atoms” represented by R ⁴ , methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, lauryl group, stearyl Linear alkyl group such as a group; branched alkyl group such as i-propyl group, 2-methylpropyl group, 1-methylpropyl group, isobutyl group, 2-ethylhexyl group; cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclo Monocyclic cycloalkyl groups such as octyl and cyclododecyl; bicyclo [2.2.1] heptyl, bicyclo [2.2.2] octyl, tricyclo [5.2.1.0 ^2,6 ] A polycyclic cycloalkyl group having a plurality of ring structures such as a decanyl group, an adamantyl group, and a tricyclo [3.3.1.1 ^3,7 ] decanyl group can be given.

  These monocyclic and polycyclic cycloalkyl groups have at least one hydrogen atom selected from at least one substituent selected from alkyl groups having 1 to 4 carbon atoms and cycloalkyl groups having 3 to 12 carbon atoms. May be substituted.

  Examples of the “alkyl group having 1 to 4 carbon atoms” include linear alkyl groups having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group; an i-propyl group and 2-methyl And a branched alkyl group having 3 to 4 carbon atoms such as a propyl group, a 1-methylpropyl group and a t-butyl group. Examples of the “C3-C12 cycloalkyl group” include a cyclopropyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.

Preferred examples of the monomer that gives the repeating unit (2) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, (Meth) acrylic acid-bicyclo [2.2.1] heptyl ester, (meth) acrylic acid-cyclohexyl ester, (meth) acrylic acid-bicyclo [4.4.0] decanyl ester, (meth) acrylic acid- Bicyclo [2.2.2] octyl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] decanyl ester, (meth) acrylic acid-adamantyl, (meth) acrylic acid-tricyclo [ 3.3.1.1 ^3,7 ] decanyl ester and the like.

  In the resin (A), one of the exemplified repeating units (2) may be contained alone, or two or more thereof may be contained.

  In the polymer (A), one of the exemplified repeating units (2) may be contained alone, or two or more thereof may be contained. In the polymer (A), the content of the repeating unit (2) is such that the total amount of the repeating unit (2) is 5 to 70 mol% with respect to all the repeating units constituting the polymer (A). Preferably, it is 5-60 mol%, and it is still more preferable that it is 5-50 mol%. By setting it as such a content rate, the developability as a resist, defect property, low LWR, low PEB temperature dependence, etc. can be improved. On the other hand, when the content of the repeating unit (2) is less than 5 mol%, the pattern collapse performance as a resist may be lowered. Moreover, when it exceeds 70 mol%, there exists a possibility that the resolution as a resist, LWR, and PEB temperature dependence may fall.

[1-3] Repeating unit (3):
The repeating unit (3) is a repeating unit containing a cyclic carbonate structure and is an essential repeating unit of the polymer (A).

  Examples of the cyclic carbonate structure of the repeating unit (3) include the structure of the following general formula (3).

In the general formula (3), R ^5, independently of one another, a hydrogen atom, a methyl group or a trifluoromethyl group. Of these, a methyl group is preferable. Moreover, several R < ⁶ > shows the C1-C5 chain hydrocarbon group which may have a hydrogen atom or a hydroxyl group mutually independently. Examples of the “chain hydrocarbon group having 1 to 5 carbon atoms” include linear alkyl groups having 1 to 5 carbon atoms such as methyl group, ethyl group, propyl group, and butyl group; isopropyl group, isobutyl group, t -C3-C5 branched alkyl groups, such as a butyl group, etc. can be mentioned.

  In the general formula (3), n represents an integer of 2 to 4. That is, the cyclic carbonate structure is a 5-membered ring structure when n = 2 (ethylene group), a 6-membered ring structure when n = 3 (propylene group), and a 7-membered structure when n = 4 (butylene group). It becomes a ring structure.

  In the general formula (3), A is a single bond, a divalent or trivalent chain hydrocarbon group having 1 to 30 carbon atoms, or a substituted or unsubstituted carbon atom, or a substituted or unsubstituted carbon atom having 3 to 30 carbon atoms. An alicyclic hydrocarbon group which may contain a divalent or trivalent heteroatom, or a substituted or unsubstituted divalent or trivalent aromatic hydrocarbon group having 6 to 30 carbon atoms. .

  When A is a single bond, the oxygen atom of (meth) acrylic acid constituting the polymer and the carbon atom forming the cyclic carbonate structure are directly bonded.

  The “chain hydrocarbon group” referred to in the present specification means a hydrocarbon group composed of only a chain structure without including a cyclic structure in the main chain. Examples of the “divalent chain hydrocarbon group having 1 to 30 carbon atoms” include a methylene group, an ethylene group, a 1,2-propylene group, a 1,3-propylene group, a tetramethylene group, and a pentamethylene group. , Hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadeca Linear alkylene groups such as methylene, octadecamethylene, nonadecamethylene, icosalen; 1-methyl-1,3-propylene, 2-methyl-1,3-propylene, 2-methyl-1 , 2-propylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group, methylidene group, ethylide And the like can be given; group, propylidene group, and a 2-propylidene group branched alkylene group. Examples of the “trivalent chain hydrocarbon group having 1 to 30 carbon atoms” include a group in which one hydrogen atom is eliminated from the functional group.

  As a specific example of the structure when A is a chain hydrocarbon group, the oxygen atom of (meth) acrylic acid constituting the polymer and the carbon atom forming the cyclic carbonate structure have 1 to 5 carbon atoms. The structure couple | bonded through these linear alkyl groups can be mentioned (refer the repeating unit (3-1)-(3-6) mentioned later). In addition, these chain hydrocarbon groups may have a substituent (see the repeating unit (3-15) described later).

  A carbon atom contained in A and a carbon atom forming a cyclic carbonate structure may be bonded to form a ring structure. In other words, the cyclic carbonate structure may constitute a part of a bridged ring or a spiro ring. When the ring structure contains two carbon atoms in the cyclic carbonate structure, a bridged ring is formed, and when only one carbon atom in the cyclic carbonate ester is contained, a spiro ring is formed. The The repeating units (3-7), (3-9), and (3-16) to (3-21) described later include a carbon atom contained in A and two carbon atoms that form a cyclic carbonate structure. This is an example in which a bridged ring including is formed. On the other hand, the repeating unit (3-10) described later is an example in which a spiro ring is formed by the carbon atom contained in A and one carbon atom forming a cyclic carbonate structure. The ring structure may be a heterocycle containing a heteroatom such as oxygen (O) or nitrogen (N) (see repeating units (3-16) to (3-21) described later).

  The “alicyclic hydrocarbon group” in the present specification means a hydrocarbon group containing only an alicyclic hydrocarbon structure in the ring structure and no aromatic ring structure. However, the “alicyclic hydrocarbon group” does not need to be composed only of the structure of the alicyclic hydrocarbon, and a part thereof may include a chain structure.

  Examples of the “divalent alicyclic hydrocarbon group” include a 1,3-cyclobutylene group, a 1,3-cyclopentylene group, a 1,4-cyclohexylene group, and a 1,5-cyclooctylene group. A monocyclic cycloalkylene group having 3 to 10 carbon atoms such as 1,4-norbornylene group, 2,5-norbornylene group, 1,5-adamantylene group, 2,6-adamantylene group, etc. An alkylene group; and the like. Examples of the “trivalent alicyclic hydrocarbon group” include a group in which one hydrogen atom is eliminated from the functional group.

  As the structure when A is an alicyclic hydrocarbon group, an oxygen atom of (meth) acrylic acid constituting a polymer and a carbon atom constituting a cyclic carbonate are bonded via a cyclopentylene group. (Refer to repeating units (3-10) described later), those bonded via a norbornylene group (refer to repeating units (3-11) and (3-12) described later), substituted tetra Examples include those bonded via a decahydrophenanthryl group (see the repeating unit (3-13) described later).

  In addition, the repeating units (3-11) and (3-12) to be described later are examples in which a bridged ring including a carbon atom contained in A and two carbon atoms constituting a cyclic carbonate is formed. It is. On the other hand, repeating units (3-10) and (3-13) described later are examples in which a spiro ring is formed by the carbon atom contained in A and one carbon atom constituting the cyclic carbonate. .

  The “aromatic hydrocarbon group” in the present specification means a hydrocarbon group containing an aromatic ring structure in the ring structure. However, the “aromatic hydrocarbon group” does not need to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic hydrocarbon structure.

  Examples of the “divalent aromatic hydrocarbon group” include arylene groups such as a phenylene group, a tolylene group, a naphthylene group, a phenanthrylene group, and an anthrylene group. Examples of the “trivalent aromatic hydrocarbon group” include a group in which one hydrogen atom is eliminated from the functional group.

  As an example in which A is an aromatic hydrocarbon group, an oxygen atom of (meth) acrylic acid constituting a polymer and a carbon atom constituting a cyclic carbonate are bonded via a benzylene group ( And the like (see repeating unit (3-14) described below). This repeating unit (3-14) is an example in which a bridged ring including a carbon atom contained in A and two carbon atoms forming a cyclic carbonate structure is formed.

  Monomers that give the repeating unit (3) are described in, for example, Tetrahedron Letters, Vol. 27, no. 32 p. 3741 (1986), Organic Letters, Vol. 4, no. 15 p. 2561 (2002), etc., and can be synthesized by a conventionally known method.

Particularly preferred examples of the repeating unit (3) include repeating units (3-1) to (3-21) represented by the following general formulas (3-1) to (3-21). In addition, ^{R 5} in the following formulas (3-1) to (3-21) has the same meaning as ^{R 5} in the general formula (3).

  In the polymer (A), only one of the exemplified repeating units (3) may be contained, or two or more kinds may be contained. The ratio of the repeating unit (3) contained in the polymer (A) is preferably 5 to 80 mol%, and preferably 5 to 70 mol%, in all repeating units constituting the polymer (A). Further preferred is 5 to 50 mol%. By making the ratio of the repeating unit (3) contained in the polymer (A) within the above range, it is possible to improve developability as a resist, low defect, low LWR, low PEB temperature dependency, and the like. . In addition, there exists a possibility that the developability and low defect property as a resist may fall that the content rate of a repeating unit (3) is less than 5 mol%. On the other hand, if it exceeds 80 mol%, the resolution as a resist, low LWR, and low PEB temperature dependence may be reduced.

  Note that “low defectivity” means that defects are less likely to occur in the photolithography process. Examples of the “defect” in the photolithography process include a watermark defect, a blob defect, a bubble defect, and the like. If a large number of these defects occur in device manufacturing, the device yield is greatly affected, which is not preferable.

  Furthermore, the “watermark defect” is a defect in which a droplet trace of the immersion liquid remains on the resist pattern, and the “blob defect” is a resin once dissolved in the developer, which is deposited by the rinse shock, The “bubble defect” refers to a defect in which a desired pattern cannot be obtained due to a change in optical path caused by the immersion liquid containing bubbles at the time of immersion exposure.

[1-4] Manufacturing method:
Next, the manufacturing method of a polymer (A) is demonstrated.

  The polymer (A) can be synthesized according to a conventional method such as radical polymerization. For example, (1) a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; (2) a solution containing the monomer and a radical A method in which a solution containing an initiator is dropped into a reaction solvent or a solution containing a monomer separately to cause a polymerization reaction; (3) a plurality of types of solutions containing each monomer, and radical initiation It is preferable to synthesize | combine by the method of dripping the solution containing an agent separately to the solution containing a reaction solvent or a monomer, respectively, and carrying out a polymerization reaction.

  In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the amount of the monomer in the dropped monomer solution is 30 mol% with respect to the total amount of monomers used for polymerization. Preferably, it is more preferably 50 mol% or more, and particularly preferably 70 mol% or more.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30-180 degreeC, 40-160 degreeC is preferable and 50-140 degreeC is still more preferable. Although dripping time changes with conditions, such as reaction temperature, the kind of initiator, and the monomer made to react, it is 30 minutes-8 hours normally, 45 minutes-6 hours are preferable, and 1-5 hours are still more preferable. Further, the total reaction time including the dropping time varies depending on the conditions as well as the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 to 6 hours.

  Examples of the radical initiator used in the polymerization include 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropionitrile), 2, And 2'-azobis (2,4-dimethylvaleronitrile). These initiators can be used alone or in admixture of two or more.

  As the polymerization solvent, any solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and capable of dissolving the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These solvents can be used alone or in admixture of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As a reprecipitation solvent, the solvent illustrated as the said polymerization solvent can be used individually or in mixture of 2 or more types. In addition to the reprecipitation method, the resin can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation. That is, after completion of the polymerization reaction, the polymerization solution is appropriately concentrated, for example, a solvent system that separates into two liquids such as methanol / heptane is selected and added, and low molecular components are removed from the resin solution, and a necessary solvent system ( And the desired resin is recovered as a solution.

  In addition, although the polymer (A) contains a low molecular weight component derived from a monomer, the content thereof is 0.1% by mass or less with respect to the total amount (100% by mass) of the polymer (A). It is preferable that it is 0.07 mass% or less, and it is especially preferable that it is 0.05 mass% or less.

  When the content of this low molecular weight component is 0.1% by mass or less, a resist film is prepared using this polymer (A), and the water in contact with the resist film is subjected to immersion exposure. It is possible to reduce the amount of eluate in Furthermore, no foreign matter is deposited in the resist during resist storage, and coating unevenness does not occur during resist application. Therefore, it is possible to sufficiently suppress the occurrence of defects when forming a resist pattern.

  In the present specification, when the term “low molecular weight component” derived from a monomer is used, the polystyrene-equivalent weight average molecular weight (hereinafter sometimes referred to as “Mw”) by gel permeation chromatography (GPC) is Mw500. It shall mean the following ingredients. Specifically, it is a component such as a monomer, dimer, trimer or oligomer. This “low molecular weight component” can be removed by, for example, chemical purification methods such as washing with water, liquid-liquid extraction, and the like, and chemical purification methods combined with physical purification methods such as ultrafiltration and centrifugation. it can.

  The low molecular weight component can be quantified by analyzing the polymer (A) by high performance liquid chromatography (HPLC). In addition to the low molecular weight component, the polymer (A) is preferably as low as possible impurities such as halogen and metal, thereby further improving the sensitivity, resolution, process stability, pattern shape, etc. when used as a resist. Can do.

  On the other hand, the polystyrene-equivalent weight average molecular weight (hereinafter referred to as “Mw”) by gel permeation chromatography (GPC) of the polymer (A) is not particularly limited, but is preferably 1,000 to 100,000. 1,000 to 30,000 is more preferable, and 1,000 to 20,000 is particularly preferable. When the Mw of the polymer (A) is less than 1,000, the heat resistance when used as a resist tends to decrease. On the other hand, when the Mw of the polymer (A) exceeds 100,000, the developability when used as a resist tends to be lowered.

  The ratio (Mw / Mn) of Mw to the number average molecular weight in terms of polystyrene (hereinafter referred to as “Mn”) by gel permeation chromatography (GPC) of the polymer (A) is usually 1.0 to 5. 0, preferably 1.0 to 3.0, and more preferably 1.0 to 2.0.

  In the resin composition of this invention, a polymer (A) can be used individually or in mixture of 2 or more types.

[2] Acid generator (B):
The acid generator (B) is a radiation-sensitive acid generator that generates an acid upon exposure. This acid generator dissociates an acid-dissociable group present in the polymer (A) contained in the radiation-sensitive resin composition by an acid generated by exposure (releases a protecting group), The polymer (A) is alkali-soluble. As a result, the exposed portion of the resist film becomes readily soluble in an alkaline developer, thereby forming a positive resist pattern.

  As an acid generator (B) in this embodiment, what contains the compound shown by the following general formula (B-1) is preferable.

In the general formula (B-1), R ¹⁴ represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, or an alkoxycarbonyl group having 2 to 11 carbon atoms, R ¹⁵ represents an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, an alkanesulfonyl group having 1 to 10 carbon atoms, R ¹⁶ is independently an alkyl group having 1 to 10 carbon atoms, A phenyl group and a naphthyl group are shown. However, two R ¹⁶ may be bonded to each other to form a divalent group having 2 to 10 carbon atoms. k represents an integer of 0 to 2, r represents an integer of 0 to 10, and X ⁻ represents an anion represented by the following general formulas (b-1) to (b-4). )
_{^{R 17 C y F 2y SO 3}} -: (b-1)
R ¹⁷ SO ₃ ⁻ : (b-2)
(In the general formulas (b-1) and (b-2), R ¹⁷ represents a hydrogen atom, a fluorine atom, or a hydrocarbon group having 1 to 12 carbon atoms, and y represents an integer of 1 to 10.)

(In the general formulas (b-3) and (b-4), R ¹⁸ independently represents a fluorine-substituted alkyl group having 1 to 10 carbon atoms, provided that two R ¹⁸ are bonded to each other. A divalent fluorine-substituted alkylene group having 2 to 10 carbon atoms may be formed.)

In the general formula (B-1), examples of the “alkyl group having 1 to 10 carbon atoms” represented by R ¹⁴ , R ¹⁵ and R ¹⁶ include n already mentioned “alkyl group having 1 to 4 carbon atoms” and n -Linear alkyl group such as pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; branched alkyl group such as neopentyl group, 2-ethylhexyl group; Etc. In these, a methyl group, an ethyl group, n-butyl group, t-butyl group etc. are preferable.

Examples of the “C1-C10 alkoxyl group” represented by R ¹⁴ and R ¹⁵ include a straight-chain alkoxyl group and a branched alkoxyl group. In these, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group etc. are preferable.

Examples of the “C2-C11 alkoxycarbonyl group” represented by R ¹⁴ include linear alkoxycarbonyl groups and branched alkoxycarbonyl groups. Of these, a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, and the like are preferable.

Examples of the “alkanesulfonyl group having 1 to 10 carbon atoms” represented by R ¹⁵ include a linear alkanesulfonyl group, a branched alkanesulfonyl group, and a cycloalkanesulfonyl group. Among these, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group, a cyclohexanesulfonyl group, and the like are preferable.

  Moreover, in general formula (B-1), it is preferable that r is an integer of 0-2.

In the general formula (B-1), as the “phenyl group” represented by R ¹⁶ , in addition to the phenyl group; o-tolyl group, m-tolyl group, p-tolyl group, 2,3-dimethylphenyl group, etc. A substituted phenyl group; a hydrogen atom of these groups is at least one group selected from the group consisting of hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group; A substituted group; and the like.

  Among the groups that substitute a hydrogen atom of a phenyl group or a substituted phenyl group, the “alkoxyl group” includes a linear alkoxyl group such as a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group; i-propoxy group And branched alkoxyl groups such as 2-methylpropoxy group, 1-methylpropoxy group and t-butoxy group; cycloalkyloxy groups such as cyclopentyloxy group and cyclohexyloxy group. These groups preferably have 1 to 20 carbon atoms.

  Examples of the “alkoxyalkyl group” include linear alkoxyalkyl groups such as methoxymethyl group, ethoxymethyl group, 2-methoxyethyl group and 2-ethoxyethyl group; branched groups such as 1-methoxyethyl group and 1-ethoxyethyl group An alkoxyalkyl group having a cycloalkane structure; and the like. These groups preferably have 1 to 20 carbon atoms.

  Examples of the “alkoxycarbonyl group” include linear alkoxycarbonyl groups such as methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, n-butoxycarbonyl group; i-propoxycarbonyl group, 2-methylpropoxycarbonyl group, 1 -Branched alkoxycarbonyl groups such as methylpropoxycarbonyl group and t-butoxycarbonyl group; cycloalkyloxycarbonyl groups such as cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl; These groups preferably have 2 to 21 carbon atoms.

  Examples of the “alkoxycarbonyloxy group” include linear alkoxycarbonyloxy groups such as methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, n-butoxycarbonyloxy group; i-propoxycarbonyloxy group, t -Branched alkoxycarbonyloxy groups such as butoxycarbonyloxy group; cycloalkyloxycarbonyl groups such as cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl; and the like. These groups preferably have 2 to 21 carbon atoms.

As the “phenyl group” represented by R ¹⁶ , a phenyl group, 4-cyclohexylphenyl group, 4-t-butylphenyl group, 4-methoxyphenyl group, 4-t-butoxyphenyl group and the like are preferable.

Examples of the “naphthyl group” represented by R ¹⁶ include 1-naphthyl group; 2-methyl-1-naphthyl group, 3-methyl-1-naphthyl group, 4-methyl-1-naphthyl group and the like. A substituted naphthyl group of the above; the hydrogen atom of these groups is at least one group selected from the group consisting of hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group And the like.

  Examples of the “alkoxyl group”, “alkoxyalkyl group”, “alkoxycarbonyl group”, and “alkoxycarbonyloxy group” that replace the hydrogen atom of the naphthyl group or substituted naphthyl group include the groups exemplified in the section of the phenyl group Can do.

Examples of the “naphthyl group” represented by R ¹⁶ include 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 and the like are preferable.

In addition, as a “divalent group having 2 to 10 carbon atoms” formed by bonding two R ¹⁶ to each other, two R ¹⁶ are bonded to each other, in the general formula (B-1) A structure in which a 5-membered ring or a 6-membered ring is formed with the sulfur atom, and a structure in which a 5-membered ring (tetrahydrothiophene ring) is formed is preferable.

  This “divalent group” has at least one hydrogen atom selected from the group consisting of hydroxyl group, carboxyl group, cyano group, nitro group, alkoxyl group, alkoxyalkyl group, alkoxycarbonyl group and alkoxycarbonyloxy group. It may be substituted with a group. A part of hydrogen atoms may be substituted. Examples of the “alkoxyl group”, “alkoxyalkyl group”, “alkoxycarbonyl group”, and “alkoxycarbonyloxy group” include the groups exemplified in the section of the phenyl group.

As R ¹⁶ , a methyl group, an ethyl group, a phenyl group, a 4-methoxyphenyl group, a 1-naphthyl group, two R ^16s are bonded to each other, and together with the sulfur atom in the general formula (B-1), tetrahydrothiophene A structure in which a ring is formed is preferable.

  Examples of the cation of the general formula (B-1) include triphenylsulfonium cation, tri-1-naphthylsulfonium cation, tri-tert-butylphenylsulfonium cation, 4-fluorophenyl-diphenylsulfonium cation, di-4-fluorophenyl- Phenylsulfonium cation, tri-4-fluorophenylsulfonium cation, 4-cyclohexylphenyl-diphenylsulfonium cation, 4-methanesulfonylphenyl-diphenylsulfonium cation, 4-cyclohexanesulfonyl-diphenylsulfonium cation, 1-naphthyldimethylsulfonium cation, 1- Naphthyldiethylsulfonium cation, 1- (4-hydroxynaphthyl) dimethylsulfonium cation, 1- (4-methylnaphthane Til) dimethylsulfonium cation, 1- (4-methylnaphthyl) diethylsulfonium cation, 1- (4-cyanonaphthyl) dimethylsulfonium cation, 1- (4-cyanonaphthyl) diethylsulfonium cation, 1- (3,5-dimethyl) -4-hydroxyphenyl) tetrahydrothiophenium cation, 1- (4-methoxynaphthyl) tetrahydrothiophenium cation, 1- (4-ethoxynaphthyl) tetrahydrothiophenium cation, 1- (4-n-propoxynaphthyl) Tetrahydrothiophenium cation, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium cation, 2- (7-methoxynaphthyl) tetrahydrothiophenium cation, 2- (7-ethoxynaphthyl) tetrahydrothioff Cation, 2- (7-n- propoxy-naphthyl) tetrahydrothiophenium cation, 2- (7-n- butoxynaphthyl) tetrahydrothiophenium cation, and the like are preferable.

In the general formula (b-1), “—C _y F _2y —” is a perfluoroalkylene group having a carbon number y and may be linear or branched. And y is preferably 1, 2, 4 or 8.

In the general formulas (b-1) and (b-2), examples of the “hydrocarbon group having 1 to 12 carbon atoms” represented by R ¹⁷ include an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, and Aburashi A cyclic hydrocarbon group is preferred.

In the general formulas (b-3) and (b-4), as the “fluorine-substituted alkyl group having 1 to 10 carbon atoms” represented by R ¹⁸ , a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, Nonafluorobutyl group, dodecafluoropentyl group, perfluorooctyl group and the like can be mentioned.

Examples of the “divalent fluorine-substituted alkylene group having 2 to 10 carbon atoms” formed by bonding two R ¹⁸ to each other include a tetrafluoroethylene group, a hexafluoropropylene group, an octafluorobutylene group, a decafluoropentylene group. Examples include a len group and an undecafluorohexylene group.

  As an anion site of the general formula (B-1), trifluoromethanesulfonate anion, perfluoro-n-butanesulfonate anion, perfluoro-n-octanesulfonate anion, 2- (bicyclo [2.2.1] hepta-2 -Yl) -1,1,2,2-tetrafluoroethanesulfonate anion, 2- (bicyclo [2.2.1] hept-2-yl) -1,1-difluoroethanesulfonate anion, 1-adamantylsulfonate anion In addition, anions represented by the following formulas (b-3a) to (b-3g) are preferable.

  The acid generator (B) is composed of combinations of cations and anions already exemplified. However, the combination is not particularly limited. In the resin composition of this invention, an acid generator (B) may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  In addition, in the resin composition of this invention, you may use together acid generators other than an acid generator (B). Examples of such acid generators include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. Specifically, the following can be mentioned.

  Examples of the “onium salt compound” include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  Examples of the “halogen-containing compound” include haloalkyl group-containing hydrocarbon compounds, haloalkyl group-containing heterocyclic compounds, and the like.

  Examples of “diazoketone compounds” include 1,3-diketo-2-diazo compounds, diazobenzoquinone compounds, diazonaphthoquinone compounds, and the like.

  Examples of the “sulfone compound” include β-ketosulfone, β-sulfonylsulfone, α-diazo compounds of these compounds, and the like.

  Examples of the “sulfonic acid compound” include alkyl sulfonic acid esters, alkyl sulfonic acid imides, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, imino sulfonates, and the like.

  These acid generators can be used singly or in combination of two or more.

  In the resin composition of the present invention, the total amount of the acid generator (B) and the other acid generator used is based on 100 parts by mass of the polymer (A) from the viewpoint of ensuring sensitivity and developability as a resist. Usually, it is 0.1-30 mass parts, and it is preferable that it is 0.5-20 mass parts. In this case, if the total amount used is less than 0.1 parts by mass, the sensitivity and developability tend to be lowered. On the other hand, when it exceeds 30 parts by mass, the transparency to radiation is lowered, and it tends to be difficult to obtain a rectangular resist pattern. Moreover, it is preferable that the usage-amount of another acid generator is 80 mass% or less with respect to the total amount of an acid generator (B) and another acid generator, and it is further 60 mass% or less. preferable.

[3] Acid diffusion inhibitor (C):
The radiation sensitive resin composition of the present invention may further contain an acid diffusion inhibitor (C) in addition to the polymer (A) and the acid generator (B) described so far. This acid diffusion inhibitor (C) controls the diffusion phenomenon in the resist film of the acid generated from the acid generator upon exposure, and suppresses an undesirable chemical reaction in the non-exposed region. By blending such an acid diffusion inhibitor (C), the storage stability of the resulting radiation-sensitive resin composition is improved, the resolution as a resist is further improved, and the heat treatment from exposure to exposure is performed. The change in the line width of the resist pattern due to the fluctuation of the holding time (PED) up to the above can be suppressed, and a composition having excellent process stability can be obtained.

  In the radiation sensitive resin composition of the present invention, a nitrogen-containing compound (C-1) represented by the following general formula (C-1) is used as the acid diffusion inhibitor (C).

[In General Formula (C-1), R ¹⁹ and R ²⁰ are each independently a hydrogen atom, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, or 3 to 20 carbon atoms. A monovalent alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms is shown. Two R ¹⁹ may be bonded to form a ring structure. ]

In the general formula (C-1), the group represented by R ²⁰ is preferably a tert-butyl group or a tert-amyl group.

In the general formula (C-1), two R ¹⁹ may be bonded to form a ring structure. For example, the nitrogen compound (C-1) in which the nitrogen atom in C-1 forms part of a cyclic amine is also included (for example, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl-2-phenyl) Benzimidazole).

  Examples of the nitrogen-containing compound represented by the general formula (C-1) include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, and Nt-butoxy. N-tert-butyl group-containing amino compounds such as carbonyldi-n-decylamine; Nt-amyloxycarbonyldi-n-octylamine, Nt-amyloxycarbonyldi-n-nonylamine, Nt-amino And N-tert-amyl group-containing amino compounds such as loxycarbonyldi-n-decylamine.

  Among these compounds, Nt-butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, (S)-(−)-1- (T-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl-4 -Hydroxypiperidine, Nt-butoxycarbonyl-2-phenylbenzimidazole, Nt-amyloxycarbonyldicyclohexylamine, Nt-amyloxycarbonyl-1-adamantylamine, Nt-amyloxycarbonyl-2- Adamantylamine, (S)-(−)-1- (t-a Roxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, Nt-amyloxycarbonylpyrrolidine, Nt-amyloxycarbonyl-4 -Hydroxypiperidine, Nt-amyloxycarbonyl-2-phenylbenzimidazole are preferred.

  Examples of the acid diffusion inhibitor (C) other than the nitrogen-containing compound (C-1) include nitrogen-containing compounds such as tertiary amine compounds, quaternary ammonium hydroxide compounds, and nitrogen-containing heterocyclic compounds.

  Examples of the “tertiary amine compound” include tri (cyclo) alkylamines such as triethylamine, tri-n-propylamine, tri-n-butylamine; aniline, N-methylaniline, N, N-dimethylaniline and the like. Aromatic amines; alkanolamines such as triethanolamine, N, N-di (hydroxyethyl) aniline; N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzenetetramethylenediamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) An ether etc. can be mentioned.

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

  Examples of the “nitrogen-containing heterocyclic compound” include pyridines such as pyridine, 2-methylpyridine and 4-methylpyridine; piperazines such as piperazine and 1- (2-hydroxyethyl) piperazine; pyrazine, pyrazole, pyridazine, Quinosaline, purine, pyrrolidine, piperidine, 3-piperidino-1,2-propanediol, morpholine, 4-methylmorpholine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, imidazole, 4 -Methylimidazole, 1-benzyl-2-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methyl Benz Imidazo , Mention may be made of N-t-butoxycarbonyl-2-phenylbenzimidazole, and the like.

  An acid diffusion inhibitor (C) can be used individually by 1 type or in mixture of 2 or more types.

  In the resin composition of the present invention, the total amount of the acid diffusion inhibitor (C) used is preferably less than 10 parts by mass with respect to 100 parts by mass of the polymer (A) from the viewpoint of ensuring high sensitivity as a resist. More preferably, it is less than 5 parts by mass. When the total amount used exceeds 10 parts by mass, the sensitivity as a resist tends to be remarkably reduced. In addition, if the usage-amount of an acid diffusion inhibitor (C) is less than 0.001 mass part, there exists a possibility that the pattern shape and dimensional fidelity as a resist may fall depending on process conditions.

[4] Solvent (D):
As the solvent (D), at least the polymer (A), the acid generator (B), the acid diffusion inhibitor (C), and a solvent that can dissolve the additive (E) if desired are particularly limited. is not. For example, alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof can be used.

  Among these, it is preferable to use propylene glycol monoalkyl ether acetates, particularly propylene glycol monomethyl ether acetate. Besides, ketones, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, γ-butyrolactone and the like are preferable. These solvent can be used individually by 1 type or in mixture of 2 or more types.

[5] Additive (E):
In the radiation sensitive resin composition of the present invention, various additives (E) such as a fluorine-containing resin, an alicyclic skeleton-containing resin, a surfactant, and a sensitizer can be blended as necessary. . The amount of each additive can be determined as appropriate according to the purpose.

  The fluorine-containing resin exhibits an action of developing water repellency on the resist film surface particularly in immersion exposure. In addition, it suppresses the elution of components from the resist film to the immersion liquid, and does not leave droplets even if immersion exposure is performed by high-speed scanning, and as a result, suppresses immersion-derived defects such as watermark defects. It is an effective ingredient.

  The structure of the fluorine-containing resin is not particularly limited. (1) Fluorine-containing resin that itself is insoluble in the developer and becomes alkali-soluble by the action of acid, and (2) itself is soluble in the developer. Fluorine-containing resin whose alkali solubility is increased by the action of acid, (3) Fluorine-containing resin which is itself insoluble in the developer and becomes alkali-soluble by the action of alkali, (4) itself is soluble in the developer And fluorine-containing resins whose alkali solubility is increased by the action of alkali.

  Examples of the “fluorine-containing resin” include resins made of a polymer having at least one repeating unit selected from the repeating unit (4) and the fluorine-containing repeating unit. Further, the repeating units (1) to (3 ), (5) and a polymer having at least one repeating unit selected from the group (6) is preferred.

  Examples of the “fluorine-containing repeating unit” include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, and the like.

  As the fluorine-containing resin, for example, polymers represented by the following general formulas (Ea) to (Ef) are preferable. These fluorine-containing resins can be used alone or in combination of two or more.

  The alicyclic skeleton-containing resin is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

  Examples of the alicyclic skeleton-containing resin include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonyl, and the like. Deoxycholic acid esters such as methyl and deoxycholic acid 2-ethoxyethyl; Lithocholic acid esters such as t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid and 2-ethoxyethyl lithocholic acid; Alkyl carboxylic acid esters such as diethyl and dipropyl adipate;

3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like. These alicyclic skeleton-containing resins can be used singly or in combination of two or more.

  A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol In addition to nonionic surfactants such as distearate, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (made by Asahi Glass Co., Ltd.), etc. Can do. These surfactants can be used individually by 1 type or in mixture of 2 or more types.

  The sensitizer absorbs radiation energy and transmits the energy to the acid generator (B), thereby increasing the amount of acid produced. It has the effect of improving the “apparent sensitivity”.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers can be used individually by 1 type or in mixture of 2 or more types.

  As the additive (E), dyes, pigments, adhesion assistants and the like can also be used. For example, by using a dye or a pigment, the latent image of the exposed area can be visualized, and the influence of halation during exposure can be reduced. Moreover, the adhesiveness with a board | substrate can be improved by mix | blending an adhesion aid. Examples of other additives include alkali-soluble resins, low-molecular alkali solubility control agents having an acid-dissociable protecting group, antihalation agents, storage stabilizers, and antifoaming agents.

  As the additive (E), one of the various additives described above may be used alone, or two or more of them may be used in combination.

[6] Photoresist pattern forming method:
The radiation sensitive resin composition of the present invention is useful as a chemically amplified resist. In a chemically amplified resist, a resin component, mainly an acid dissociable group in the polymer (A), is dissociated by the action of an acid generated from an acid generator by exposure to generate a carboxyl group. As a result, the solubility of the exposed portion of the resist in the alkaline developer is increased, and the exposed portion is dissolved and removed by the alkaline developer to obtain a positive photoresist pattern.

(Photoresist pattern formation method)
As a method for forming a photoresist pattern, for example, a photoresist pattern is generally formed as follows. (1) After forming a photoresist film on the substrate using the radiation-sensitive resin composition (step (1)), (2) the formed photoresist film (with an immersion medium if necessary) ), Exposing by exposure to radiation through a mask having a predetermined pattern (step (2)), heating the substrate (exposed photoresist film) (step (3)), and then (4) developing ( Step (4)), a photoresist pattern can be formed.

  In the step (1), a radiation sensitive resin composition or a composition solution obtained by dissolving it in a solvent is applied to a substrate (silicon wafer) by an appropriate application means such as spin coating, cast coating, roll coating or the like. , Silicon dioxide, a wafer coated with an antireflection film, etc.) to form a photoresist film. Specifically, after applying the resin composition solution so that the obtained resist film has a predetermined film thickness, the solvent in the coating film is volatilized by pre-baking (PB) to form a resist film.

  In step (2), the photoresist film formed in step (1) is irradiated with radiation (possibly through an immersion medium such as water) and exposed. In this case, radiation is irradiated through a mask having a predetermined pattern. As the radiation, irradiation is performed by appropriately selecting from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like according to the line width of the target pattern. Far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser is particularly preferable.

  Step (3) is called post-exposure bake (PEB), and is a step in which the acid generated from the acid generator deprotects the polymer in the exposed portion of the photoresist film in step (2). There is a difference in the solubility of the exposed portion (exposed portion) and the unexposed portion (unexposed portion) in the alkaline developer. PEB is usually carried out by appropriately selecting in the range of 50 ° C to 180 ° C.

  In step (4), the exposed photoresist film is developed with a developer to form a predetermined photoresist pattern. After development, it is common to wash with water and dry. As the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous 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 aqueous alkaline solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable.

  Also, when performing immersion exposure, before the step (2), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. As the protective film for immersion, a solvent-peeling type protective film (see, for example, Japanese Patent Application Laid-Open No. 2006-227632) that peels off with a solvent before the step (4), a development that peels off simultaneously with the development in the step (4) Any of liquid-removable protective films (see, for example, WO2005-069096 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, the part is based on mass unless otherwise specified. Each measurement and evaluation in Examples and Comparative Examples was performed as follows.

Polystyrene equivalent weight average molecular weight (Mw):
A gel based on monodisperse polystyrene using Tosoh's GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. Measured by permeation chromatography (GPC).

Polystyrene equivalent number average molecular weight (Mn):
A gel based on monodisperse polystyrene using Tosoh's GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. Measured by permeation chromatography (GPC).

[ ¹³ C-NMR analysis]:
The ¹³ C-NMR analysis of each polymer was measured using a nuclear magnetic resonance apparatus (trade name: JNM-ECX400, manufactured by JEOL Ltd.).

(Synthesis of polymer (A))
Resins (A-1) to (A-4) were synthesized using the following monomers (M-1) to (M-4) in the respective synthesis examples. Monomers (M-1) to (M-2) are monomers corresponding to the repeating unit (1), and the monomer (M-4) is a monomer corresponding to the repeating unit (2). The body (M-3) is a monomer corresponding to the repeating unit (3).

(Synthesis Example 1: Resin (A-1))
Monomer (M-1) 27.42 g (50 mol%), Monomer (M-4) 5.16 g (10 mol%), Monomer (M-3) 17.43 g (40 mol%) Was dissolved in 100 g of 2-butanone, and a monomer solution containing 2.27 g (5 mol%) of dimethyl 2,2′-azobis (2-methylpropionate) as an initiator was prepared.

  Next, 50 g of 2-butanone was charged into a 500 ml three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using a dropping funnel, a monomer solution prepared in advance 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, the polymerization solution was cooled to 30 ° C. or less by water cooling. After cooling, it was poured into 1000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was slurried with 200 g of methanol and washed twice. Thereafter, the white powder was again filtered off and dried at 50 ° C. for 17 hours to obtain a white powder copolymer (39 g, yield 78%). This copolymer was referred to as “resin (A-1)”.

This copolymer has Mw of 6520, Mw / Mn of 1.61, and as a result of ¹³ C-NMR analysis, monomer (M-1), monomer (M-4), and single monomer The content rate of each repeating unit derived from a body (M-3) was 50.2: 9.5: 40.3 (mol%).

(Synthesis Example 2: Resins (A-2) to (A-4)
Resins (A-2) to (A-4) were synthesized in the same manner as in Synthesis Example 1, except that the formulation shown in Table 1 was used.

Moreover, about the obtained resin (A-2)-(A-4), the ratio (mol%) of each repeating unit by ¹³ C-NMR analysis, a yield (%), Mw, and dispersity (Mw / The measurement results of Mn) are shown in Table 2.

(Preparation of radiation-sensitive resin composition)
Table 3 shows the compositions of the radiation-sensitive resin compositions prepared in each example and comparative example. Moreover, each component (an acid generator (B), an acid diffusion inhibitor (C), and a component constituting a radiation-sensitive resin composition other than the resins (A-1) to (A-4) synthesized in the above synthesis example) The solvent (D)) is shown below.

<Acid generator (B)>
(B-1): Triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate

<Acid diffusion inhibitor (C)>
(C-1): Nt-butoxycarbonyl-4-hydroxypiperidine

<Solvent (D)>
(D-1): Propylene glycol monomethyl ether acetate,
(D-2): cyclohexanone,
(D-3): γ-butyrolactone

Example 1
100 parts by mass of the resin (A-1) obtained in Synthesis Example 1 and the acid generator (B), (B-1): triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl- 7.5 parts by mass of 1,1-difluoroethanesulfonate and 0.9 parts by mass of (C-1): Nt-butoxycarbonyl-4-hydroxypiperidine were mixed as the acid diffusion inhibitor (C). As a solvent (D), (D-1) 1500 parts by mass of propylene glycol monomethyl ether acetate, (D-2) 650 parts by mass of cyclohexanone and (D-3) 30 parts by mass of γ-butyrolactone were added to dissolve the above mixture. Thus, a mixed solution was obtained, and the obtained mixed solution was filtered through a filter having a pore size of 0.20 μm to prepare a radiation sensitive resin composition.

(Example 2, Comparative Examples 1-2)
Radiation-sensitive resin composition (Example 2), (Comparison) as in Example 1, except that the composition of each component for preparing the radiation-sensitive resin composition was changed as shown in Table 3. Examples 1 and 2) were obtained.

[Evaluation methods]
About the obtained radiation sensitive resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2, using ArF excimer laser as a light source, sensitivity, dense line focal depth, isolated space focal depth, LWR, MEEF, minimum pre-collapse dimensions And the number of development defects were evaluated. The evaluation results are shown in Table 4.

Sensitivity (unit: mJ / cm ² ):
A lower antireflection film having a film thickness of 77 nm was formed on an 8-inch wafer surface using a lower antireflection film forming agent (trade name: ARC29A, manufactured by Nissan Chemical Industries, Ltd.). The radiation-sensitive resin compositions of Examples and Comparative Examples were applied to the surface of this substrate by spin coating, and subjected to SB (Soft Bake) for 90 seconds at a temperature shown in Table 4 on a hot plate, and the film thickness was 120 nm. A resist film was formed.

  This resist film was exposed through a mask pattern using a full-field reduction projection exposure apparatus (trade name: S306C, Nikon Corporation, numerical aperture 0.78). Thereafter, PEB was performed for 90 seconds at the temperature shown in Table 4, and then developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution (hereinafter referred to as “TMAH aqueous solution”) at 25 ° C. for 60 seconds, followed by washing with water. And dried to form a positive resist pattern.

At this time, the exposure amount (mJ / cm ² ) formed in a one-to-one line and space with a line width of 90 nm is defined as an optimum exposure amount through a mask with a one-to-one line and space with a dimension of 90 nm. The optimum exposure amount (mJ / cm ² ) was defined as “sensitivity”. A scanning electron microscope (trade name: S9220, manufactured by Hitachi High-Technologies Corporation) was used for length measurement.

Depth of focus (DOF) of isolated lines:
The focus fluctuation width when the pattern dimension resolved with the 90 nm 1L / 1S mask pattern at the optimum exposure dose is within ± 10% of the mask design dimension was defined as the dense line focal depth. Specifically, it was evaluated as “good” when the dense line focal depth was 0.40 μm or more, and “bad” when it was less than 0.40 μm. The scanning electron microscope was used for observing the pattern dimensions.

Exposure margin (EL):
The exposure margin was defined as the ratio of the exposure amount range when the pattern dimension resolved by the 90 nm 1L / 1S mask pattern was within ± 10% of the mask design dimension to the optimum exposure amount. Specifically, it was evaluated as “good” when the exposure margin was 10% or more, and “bad” when it was less than 10%. The scanning electron microscope was used for observing the pattern dimensions.

Pattern roughness (LWR):
Using the scanning electron microscope, when observing a 90 nm 1L / 1S pattern resolved at the optimum exposure amount from the top of the pattern, the line width was measured at 10 points at arbitrary points, and the 3 sigma value of the measured value (Variation) was defined as LWR. The smaller this value, the better. Specifically, when the LWR was 8.0 nm or less, it was evaluated as “good”, and when it exceeded 8.0 nm, it was evaluated as “bad”.

MEEF:
Using the scanning electron microscope, the optimal exposure dose is 5 types of mask sizes (85.0 nm L / 180 nm P, 87.5 nm L / 180 nm P, 90.0 nm L / 180 nm P, 92.5 nm L / 180 nm P, 95.0 nm L / 180 nm P). Resolved pattern dimensions were measured. The measurement results were plotted with the horizontal axis representing the mask size and the vertical axis representing the line width, and the slope of the graph was determined by the least square method. This inclination was defined as MEEF. Specifically, it was evaluated as “good” when the MEEF was 4.0 or more and “bad” when it was less than 4.0.

Pattern cross-section:
The cross-sectional shape of the line-and-space pattern with a line width of 90 nm resolved with the above sensitivity is observed with the trade name “S-4200” (manufactured by Hitachi High-Technologies Corporation), and the line width in the middle of the resist pattern Lb and the line width La at the upper part of the film are measured, and the case where it is within the range of 0.9 ≦ (La / Lb) ≦ 1.1 is evaluated as “good”, and the case where it is out of range is determined as “bad”. It was evaluated.

The radiation sensitive resin composition of the present invention can be suitably used as a lithography material using a KrF excimer laser and an ArF excimer laser as a light source. Moreover, it can respond also to immersion exposure.

Claims (2)

Polymer (A) containing at least one type of repeating unit represented by the following general formulas (1) and (2) and a repeating unit (3) having a cyclic carbonate structure, and a radiation sensitive acid generator (B) A radiation-sensitive resin composition.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )
(In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, the general formula (1) (Excluding repeating units represented by A polymer comprising one or more types of repeating units represented by the following general formulas (1) and (2) and a repeating unit (3) having a cyclic carbonate structure.

(In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, or 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof, or a divalent hydrocarbon group of 4 to 20 carbon atoms formed by bonding any two R ² to each other. )
(In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group. However, the general formula (1) (Excluding repeating units represented by