JP5678449B2 - Radiation sensitive composition - Google Patents

Description

The present invention relates to a radiation-sensitive composition. More specifically, for microfabrication by various types of radiation such as KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV (extreme) deep ultraviolet rays, synchrotron radiation, etc., X-rays, electron beams, etc. It relates to radiation-sensitive compositions used as suitable chemically amplified resist.

  Conventionally, in a manufacturing process of a semiconductor device such as an IC or LSI, fine processing by lithography using a photoresist composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in the submicron region and the quarter micron region has been required. Along with this, there is a tendency to shorten the exposure wavelength from g-line to i-line, KrF excimer laser light, and further ArF excimer laser light. Further, in addition to excimer laser light, lithography using electron beams, X-rays, or EUV light is also being developed.

  Lithography using EUV light is positioned as a next-generation or next-generation pattern forming technique, and a positive resist with high sensitivity and high resolution is desired. In particular, high sensitivity is a very important issue for shortening the wafer processing time. However, in the positive resist for EUV, if high sensitivity is pursued, not only the resolution is lowered but also the nano edge roughness is deteriorated. Therefore, it is strongly desired to develop a resist that simultaneously satisfies these characteristics. ing. Nano edge roughness is designed when the pattern is viewed from directly above because the resist pattern and the edge of the substrate interface vary irregularly in the direction perpendicular to the line direction due to the characteristics of the resist. This refers to the deviation that occurs between the dimensions and the actual pattern dimensions. Since the deviation from the design dimension is transferred by an etching process using a resist as a mask and the electrical characteristics are deteriorated, the yield is lowered. In particular, in the ultrafine region of 32 nm or less where EUV is about to be applied, nano edge roughness is an extremely important improvement issue. High sensitivity, high resolution, good pattern shape, and good nanoedge roughness are in a trade-off relationship, and how to satisfy them simultaneously is very important.

  As for the positive resist for EUV, the resist technology for KrF excimer laser has been mainly diverted so far. For example, Patent Document 1 discloses a radiation-sensitive resin composition containing a copolymer of 4-hydroxystyrene and 2-methyl-2-adamantyl acrylate. Patent Document 2 discloses a radiation-sensitive resin composition using two types of photoacid generators. Further, Patent Document 3 discloses a radiation-sensitive resin composition that uses a photoacid generator that generates a strong acid and a photoacid generator that generates a weak acid, and Patent Documents 4 and 5 disclose oxoacids. A radiation sensitive resin composition using a compound that generates an acid other than the above is disclosed.

JP 2001-166478 A Japanese Patent Laid-Open No. 5-323590 JP-A-5-181279 JP 2002-6482 A JP-A-8-526859

  However, even if the radiation-sensitive resin compositions disclosed in Patent Documents 1 to 5 are used, at present, high sensitivity, high resolution, good pattern shape, and good nanoedge roughness cannot be satisfied at the same time. is there.

  The present invention has been made in view of the above-described problems of the prior art, and the problem is that KrF excimer laser, ArF excimer laser, EUV and other (ultra) far ultraviolet rays, synchrotron radiation, etc. A radiation-sensitive composition capable of forming a chemically amplified positive resist film that can effectively form X-rays and electron beams, has excellent sensitivity, and can form fine patterns with high accuracy and stability. There is to do.

  As a result of intensive studies to achieve the above problems, the present inventors have found that the above problems can be achieved by containing a sulfonimide compound represented by a specific structural formula. It came to be completed.

That is, according to this invention, the radiation sensitive composition shown below is provided.

[1] A radiation-sensitive composition containing a sulfonimide compound represented by the following general formula (1- a ) (hereinafter also referred to as “compound (C)”), an acid-dissociable group-containing compound, and a solvent. object.

（前記一般式（１−ａ）中、Ｍ^＋は、一価のオニウムカチオンを示す。Ｒ ^ｘ は、炭素数１〜１２の直鎖状若しくは分岐状のアルキル基、アリール基、アラルキル基、アシル基、又は脂環式炭化水素基を示す。ｘは、０〜２の整数を示す。）

(In the general formula (1- a ), M ⁺ represents a monovalent onium cation. R ^x represents a linear or branched alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group, an acyl group. Group represents an alicyclic hydrocarbon group, and x represents an integer of 0 to 2. )

  [2] The acid dissociable group-containing compound is a repeating unit represented by the following general formula (2) and at least one repeating unit represented by the following general formula (3) (hereinafter, “repeating” The radiation-sensitive composition according to [1], which is a resin having a unit (1) ”.

（前記一般式（２）中、Ｒ^１は、水素原子、メチル基、トリフルオロメチル基、又はヒドロキシメチル基を示す。複数のＲ^２は、相互に独立に、炭素数４〜２０の一価の脂環式炭化水素基、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。但し、いずれか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共に脂環式炭化水素基を形成してもよい。）

(In the general formula (2), R ¹ represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. The plurality of R ² are independently monovalent from 4 to 20 carbon atoms. shown alicyclic hydrocarbon group, or a linear or branched alkyl group having 1 to 4 carbon atoms. However, any two of R ² are bonded to each other, the carbon atom to which each is attached And an alicyclic hydrocarbon group may be formed together.)

（前記一般式（３）中、Ｒ^１は、水素原子、メチル基、トリフルオロメチル基、又はヒドロキシメチル基を示す。複数のＲ^２は、相互に独立に、炭素数４〜２０の一価の脂環式炭化水素基、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。但し、いずれか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共に脂環式炭化水素基を形成してもよい。）

(In the general formula (3), R ¹ represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. The plurality of R ² are independently monovalent from 4 to 20 carbon atoms. shown alicyclic hydrocarbon group, or a linear or branched alkyl group having 1 to 4 carbon atoms. However, any two of R ² are bonded to each other, the carbon atom to which each is attached And an alicyclic hydrocarbon group may be formed together.)

[3] In the above [1] or [2], further containing a radiation-sensitive acid generator including an onium salt represented by the following general formula (4) (hereinafter also referred to as “acid generator (B)”) The radiation-sensitive composition described.
A ⁺ B ⁻ : (4)
(In the general formula (4), A ⁺ represents a monovalent onium cation. B ⁻ represents a monovalent anion represented by the following general formula (B-1) or the following general formula (B-2). Show.)

R ³ C _n F _2n SO ₃ ⁻ : (B-1)
R ⁴ SO ₃ ⁻ : (B-2)
(R ³ in the general formula (B-1) and R ⁴ in the general formula (B-2) represent a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms. In general formula (B-1), n represents an integer of 1 to 10.)

  The radiation sensitive composition of the present invention is sensitive to X-rays such as KrF excimer laser, ArF excimer laser, EUV (extreme) deep ultraviolet rays, synchrotron radiation, and electron beams, and nano edge roughness, sensitivity and resolution. It is possible to form a chemically amplified positive resist film capable of forming a fine pattern with high accuracy and stability.

It is a schematic diagram which shows a line pattern.

  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. Sulfonimide compounds:
Scan Ruhon'imido compound is a compound represented by the general formula (1). The compound (C) usually exhibits basicity, but in the lithography process, by irradiating the resist film with an electron beam, radiation or the like, a sulfonimide is generated in the resist film and loses basicity. Therefore, it will decompose in the exposed area and will not affect the dissociation reaction of the acid dissociable group, but it will react with the acid generated from the acid generator in the unexposed area to suppress the dissociation reaction in the unexposed area. Can do.

In the general formula (1- a ), M ⁺ is a monovalent onium cation, preferably a sulfonium cation or an iodonium cation, and particularly preferably a sulfonium cation represented by the general formula (5). .

（一般式（５）中、複数のＲ^５は、相互に独立に、置換されていてもよい炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、又は置換されていてもよい炭素数６〜１８のアリール基を示す。但し、いずれか２つのＲ^５が相互に結合してイオウカチオンとともに環状構造を形成し、残りの１つのＲ^５が置換されていてもよい炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、又は置換されていてもよい炭素数６〜１８のアリール基であってもよい。）

(In General Formula (5), several R < ⁵ > is the C1-C10 linear or branched alkyl group which may be substituted mutually independently, or the carbon number which may be substituted. 6 to 18 aryl group, provided that any two R ^{5 's} are bonded to each other to form a cyclic structure with a sulfur cation, and the remaining one R ⁵ may be substituted with 1 to 10 carbon atoms. Or a linear or branched alkyl group, or an optionally substituted aryl group having 6 to 18 carbon atoms.)

R ^x in the formula (1-a) shows a linear or branched alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group, an acyl group, or an alicyclic hydrocarbon group. In general formula (1-a) , x represents an integer of 0-2. )

Specific examples of the compound represented by the general formula (1- a) include compounds represented by the following formula (1-1 ) .

(Synthesis method)
Compound (C) can be synthesized, for example, as shown in the following reaction formula. First, the compound represented by the general formula (6) is reacted with sodium hydrogen carbonate in an aqueous solution to obtain a compound represented by the general formula (7). Next, it can be synthesized by reacting with a desired onium cation M ⁺ halide (for example, M ⁺ Br ⁻ ) in an aqueous solution.

（一般式（６）〜（８）中、Ｙは、カルボニル基を示す。Ｒ^ａ及びＲ^ｂは、相互に独立に、炭素数１〜１２の直鎖状若しくは分岐状のアルキル基、アリール基、アラルキル基、アシル基、又は脂環式炭化水素基を示す。但し、Ｒ^ａとＲ^ｂとが結合してＲ^ａとＲ^ｂの炭素数を足して員数６〜１２の環状構造を形成しても良い。また、一般式（８）中、Ｍ^＋は、一価のオニウムカチオンを示す。）

(In General Formulas (6) to (8), Y represents a carbonyl group. R ^a and R ^b are each independently a linear or branched alkyl group having 1 to 12 carbon atoms or an aryl group. , an aralkyl group, an acyl group, or an alicyclic hydrocarbon group. However, forming a cyclic structure membered 6-12 by adding the number of carbon atoms in R ^a and R ^b are bonded with each R ^a and R ^b In general formula (8), M ⁺ represents a monovalent onium cation.)

II. Radiation sensitive composition:
The radiation-sensitive composition of the present invention contains the sulfonimide compound described in “I. Sulfonimide compound”, an acid-dissociable group-containing compound, and a solvent, and usually generates a radiation-sensitive acid. It further contains an agent. By containing compound (C), the dissociation reaction due to the acid generated from the radiation-sensitive acid generator proceeds in the radiation-irradiated region, and in the non-irradiated region, the dissociation reaction due to the diffusion of the acid generated in the irradiated region. Can be suppressed. Therefore, the dimensional accuracy of the formed resist pattern is very good.

1. Acid-dissociable group-containing compound:
Examples of the acid-dissociable group-containing compound include an acid-dissociable group-containing resin (hereinafter referred to as “resin (A)”) or an acid-dissociable group-containing low molecular compound having a molecular weight of 5000 or less. Among these, resin (A) is preferable.

(Resin (A))
The resin (A) is a resin having a repeating unit having an acid-dissociable group, and is usually a resin that is insoluble in alkali or hardly soluble in alkali and easily soluble in alkali by the action of an acid. The term “alkali insoluble or alkali insoluble” as used herein refers to the alkali development conditions employed when a resist pattern is formed from a resist film formed using a radiation-sensitive composition containing the resin (A). Thus, when a 100 nm-thick film using only the resin (A) is developed instead of the resist film, 50% or more of the initial film thickness remains after development.

  When the radiation sensitive composition contains such a resin (A), the sensitivity is particularly excellent. Therefore, in a lithography process, a chemically amplified positive resist film that is sensitive to electron beams or extreme ultraviolet rays, has low roughness, is excellent in sensitivity and resolution, and can form fine patterns with high accuracy and stability. Can be formed.

(1) Component:
The resin (A) is preferably a resin having the repeating unit (1).

Among the groups represented by R ² in the general formula (2), examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and i. -Propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include cyclohexane such as norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane. Groups composed of alicyclic rings derived from alkanes and the like; groups composed of these alicyclic rings are, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- Examples thereof include a group substituted with one or more of a linear or branched alkyl group having 1 to 4 carbon atoms such as a methylpropyl group, a 1-methylpropyl group, and a t-butyl group, or a cycloalkyl group. Furthermore, as the alicyclic hydrocarbon group formed together with the carbon atom to which any two R ² are bonded to each other, for example, norbornane, tricyclodecane, tetracyclododecane, adamantane, Examples thereof include groups composed of alicyclic rings derived from cyclopentane and cyclohexane, and groups obtained by substituting these alicyclic rings with the alkyl group.

In the general formula (3), specific examples of the group represented by R ² has the general formula (2), it can be said as with the group represented as R ^2.

  Among the repeating units (1), the repeating units represented by the general formulas (2-1) to (2-7) and the repeating unit represented by the general formula (3-1) are preferable, and the general formula (2- The repeating units represented by 2) to (2-4) are particularly preferable.

（一般式（２−１）〜（２−７）及び（３−１）中、Ｒ^１は、水素原子、メチル基、トリフルオロメチル基、又はヒドロキシメチル基を示す。Ｒ^６は、炭素数１〜４の直鎖状又は分岐状のアルキル基を示す。但し、Ｒ^６が複数存在する場合は相互に独立である。）

(In General Formulas (2-1) to (2-7) and (3-1), R ¹ represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. R ⁶ represents the number of carbon atoms. 1 to 4 linear or branched alkyl groups, provided that a plurality of R ⁶ are present independently of each other.

  In addition, resin (A) may have only 1 type of repeating units (1), and may have 2 or more types.

  The resin (A) may be composed only of the repeating unit (1), but in addition to the repeating unit (1), the repeating unit represented by the general formula (9) (hereinafter referred to as “repeating unit (2)”). The repeating unit represented by the general formula (10) (hereinafter referred to as “repeating unit (3)”) and the repeating unit represented by the general formula (11) (hereinafter referred to as “repeating unit (4)”). It is further preferred to have at least one repeating unit selected from the group consisting of

（一般式（９）中、Ｒ^７は、水素原子又はメチル基を示す。Ｒ^８は、炭素数１〜１２の直鎖状若しくは分岐状のアルキル基、又は炭素数１〜１２の直鎖状若しくは分岐状のアルコキシル基を示す。ｉは、０〜３の整数を示す。ｊは、０〜３の整数を示す。但し、ｉ＋ｊ≦５である。）

(In General Formula (9), R ⁷ represents a hydrogen atom or a methyl group. R ⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear structure having 1 to 12 carbon atoms. Alternatively, it represents a branched alkoxyl group, i represents an integer of 0 to 3. j represents an integer of 0 to 3, provided that i + j ≦ 5.

（一般式（１０）中、Ｒ^７は、水素原子又はメチル基を示す。Ｒ^８は、炭素数１〜１２の直鎖状若しくは分岐状のアルキル基、又は炭素数１〜１２の直鎖状若しくは分岐状のアルコキシル基を示す。ｋは、０〜３の整数を示す。ｌは、０〜３の整数を示す。但し、ｋ＋ｌ≦５である。）

(In General Formula (10), R ⁷ represents a hydrogen atom or a methyl group. R ⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear structure having 1 to 12 carbon atoms. Or a branched alkoxyl group, k represents an integer of 0 to 3. l represents an integer of 0 to 3, provided that k + l ≦ 5.

（一般式（１１）中、Ｒ^７は、水素原子又はメチル基を示す。Ｒ^８は、炭素数１〜１２の直鎖状若しくは分岐状のアルキル基、又は炭素数１〜１２の直鎖状若しくは分岐状のアルコキシル基を示す。ｍは、０〜３の整数を示す。ｎは、０〜３の整数を示す。但し、ｍ＋ｎ≦５である。）

(In General Formula (11), R ⁷ represents a hydrogen atom or a methyl group. R ⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, or a linear structure having 1 to 12 carbon atoms. Or a branched alkoxyl group, m represents an integer of 0 to 3. n represents an integer of 0 to 3, provided that m + n ≦ 5.

Among the groups represented by R ⁸ in the general formula (9), examples of the linear or branched alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and i- Examples include propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like. Moreover, as a C1-C12 linear or branched alkoxyl group, a methoxy group, an ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1 -Methylpropoxy group, t-butoxy group and the like. Among these, the group represented as R ⁸ is preferably a methyl group, an ethyl group, an n-butyl group, or a t-butyl group.

  In general formula (9), i is an integer of 0 to 3, and is more preferably 1 or 2. Moreover, j is an integer of 0-3, and it is more preferable that it is an integer of 0-2.

  Specific examples of the repeating unit (2) include repeating units represented by formulas (9-1) to (9-4). In addition, when resin (A) has a repeating unit (2), it may have only 1 type of repeating unit (2), and may have 2 or more types.

Specific examples of the linear or branched alkyl group having 1 to 12 carbon atoms and the linear or branched alkoxyl group having 1 to 12 carbon atoms among the groups represented by R ⁸ in general formula (10). As an example, the same thing as the group represented by R ⁸ in general formula (9) can be said.

  In general formula (10), k is an integer of 0 to 3, and is more preferably 1 or 2. L is an integer of 0 to 3, and is more preferably 0 or 1.

  Specific examples of the repeating unit (3) include repeating units represented by formulas (10-1) and (10-2). In addition, when resin (A) has a repeating unit (3), it may have only 1 type of repeating units (3), and may have 2 or more types.

Specific examples of the linear or branched alkyl group having 1 to 12 carbon atoms and the linear or branched alkoxyl group having 1 to 12 carbon atoms among the groups represented by R ⁸ in general formula (11). As an example, the same thing as the group represented by R ⁸ in general formula (9) can be said.

  In general formula (11), m is an integer of 0 to 3, and is more preferably 1 or 2. N is an integer of 0 to 3, more preferably 0 or 1.

  Specific examples of the repeating unit (4) include repeating units represented by formulas (11-1) and (11-2). In addition, when resin (A) has a repeating unit (4), it may have only 1 type of repeating units (4), and may have 2 or more types.

  The polymer which has a repeating unit represented by Formula (9-1)-(9-3) can be obtained by superposing | polymerizing using a corresponding hydroxy styrene derivative as a monomer. Furthermore, it can also obtain by superposing | polymerizing using the compound which can obtain a hydroxy styrene derivative as a monomer by hydrolyzing. As monomers used for obtaining a polymer having a repeating unit represented by the formulas (9-1) to (9-3), p-acetoxystyrene, p- (1-ethoxyethoxy) styrene, and the like can be given. preferable. When these monomers are used, a polymer having repeating units represented by the formulas (9-1) to (9-3) is obtained by polymerizing and then hydrolyzing the side chain. .

  Moreover, the polymer which has a repeating unit represented by Formula (9-4), (10-1), (10-2), (11-1), and (11-2) is a corresponding monomer. It can obtain by superposing | polymerizing using. Monomer used to obtain a polymer having repeating units represented by formulas (9-4), (10-1), (10-2), (11-1), and (11-2) As such, p-isopropenylphenol, 4-hydroxyphenyl acrylate, 4-hydroxyphenyl methacrylate, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide and the like are preferable.

  The resin (A) may further have a repeating unit derived from a non-acid dissociable compound (hereinafter referred to as “repeating unit (5)”) in addition to the repeating units (1) to (4).

  Non-acid dissociable compounds include, for example, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, isobornyl acrylate, tricyclodecanyl (meth) acrylate, and tetracyclodode. Examples thereof include senyl (meth) acrylate and a compound represented by the formula (12). Among these, styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, tricyclodecanyl acrylate, and a compound represented by the formula (12) are preferable. In addition, when resin (A) has a repeating unit (5), it may have only 1 type of repeating units (5), and may have 2 or more types.

  The content of the repeating unit (1) is preferably 1 mol% or more, more preferably 20 to 70 mol%, when the total of all repeating units in the resin (A) is 100 mol%, more preferably 20 to 70 mol%. More preferably, it is 60 mol%. When the content of the repeating unit (1) is 1 mol% or more, the nano edge roughness can be excellent.

  The total content of the repeating units (2) to (4) is preferably 1 to 95 mol% when the total of all repeating units in the resin (A) is 100 mol%, and preferably 10 to 95 mol%. It is more preferable that it is 40 to 80 mol%. When the total content of the repeating units (2) to (4) is more than 95 mol%, the nano edge roughness may be deteriorated.

  Furthermore, the total content of the repeating units (1) to (4) is preferably 10 mol% or more when the total of all repeating units in the resin (A) is 100 mol%, and is 40 to 100 mol%. More preferably, it is more preferably 50 to 100 mol%. When the total content of the repeating units (1) to (4) is 10 mol% or more, the nano edge roughness can be excellent.

  The content of the repeating unit (5) is usually 60 mol% or less and preferably 50 mol% or less when the total of all repeating units in the resin (A) is 100 mol%. When the content of the repeating unit (5) is 60 mol% or less, the performance balance between the resolution performance and the nano edge roughness can be excellent.

(2) Preparation method:
Although the preparation method of resin (A) is not specifically limited, For example, it can carry out by well-known radical polymerization or anionic polymerization. Further, the side chain hydroxystyrene units in the repeating units (2) to (4) can be obtained by hydrolysis of an acetoxy group or the like in the presence of a base or an acid in an organic solvent after completion of the polymerization reaction. .

  In the radical polymerization, for example, a necessary monomer such as a monomer giving the repeating unit (1) is stirred and heated in a suitable organic solvent in a nitrogen atmosphere in the presence of a radical polymerization initiator. Can be implemented.

  Examples of the radical polymerization initiator include azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis- (2,4-dimethylvaleronitrile); benzoyl peroxide, lauroyl peroxide, and the like. Organic peroxides; hydrogen peroxide, etc. In this polymerization, a polymerization aid such as 2,2,6,6-tetramethyl-1-piperidinyloxy, iodine, mercaptan, styrene dimer may be added as necessary.

  The reaction temperature in radical polymerization is not particularly limited, and is appropriately selected depending on the type of radical polymerization initiator (for example, 50 to 200 ° C.). In particular, when an azo initiator or a peroxide initiator is used, a temperature at which the half-life of the radical polymerization initiator is about 10 minutes to 30 hours is preferable, and the half-life of the radical polymerization initiator is 30 minutes to 10 minutes. A temperature that is on the order of hours is more preferable. The reaction time varies depending on the type of radical polymerization initiator and the reaction temperature, but the reaction time during which 50% or more of the radical polymerization initiator is consumed is desirable, and is usually about 0.5 to 24 hours.

  In the anionic polymerization, for example, necessary monomers such as the repeating unit (1) are stirred and maintained at a predetermined temperature in a suitable organic solvent in a nitrogen atmosphere in the presence of an anionic polymerization initiator. Can be implemented.

  Examples of the anionic polymerization initiator include n-butyl lithium, s-butyl lithium, t-butyl lithium, ethyl lithium, ethyl sodium, 1,1-diphenylhexyl lithium, 1,1-diphenyl-3-methylpentyl lithium, and the like. There are organic alkali metals.

  The reaction temperature in anionic polymerization is not particularly limited, and is appropriately selected depending on the type of anionic polymerization initiator and the like. In particular, when alkyllithium is used as an anionic polymerization initiator, the temperature is preferably −100 to 50 ° C., more preferably −78 to 30 ° C. The reaction time varies depending on the type of anionic polymerization initiator and the reaction temperature, but the reaction time during which 50% or more of the anionic polymerization initiator is consumed is desirable, and is usually about 0.5 to 24 hours.

  In the preparation of the resin (A), it is possible to carry out a polymerization reaction by heating or cationic polymerization without using a polymerization initiator.

  When the hydroxystyrene unit is introduced by hydrolyzing the side chain of the resin (A), examples of the acid used for the hydrolysis reaction include p-toluenesulfonic acid and its hydrate, methanesulfonic acid, trifluoro Inorganic acids such as lomethanesulfonic acid; salts such as pyridinium p-toluenesulfonate. Examples of the base include inorganic bases such as potassium hydroxide and sodium hydroxide; organic bases such as triethylamine and piperidine.

  Examples of the organic solvent used for polymerization and hydrolysis include ketones such as acetone, methyl ethyl ketone, and methyl amyl ketone; ethers such as diethyl ether and tetrahydrofuran (THF); alcohols such as methanol, ethanol, and propanol; Aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated alkyls such as chloroform, bromoform, methylene chloride, methylene bromide and carbon tetrachloride; ethyl acetate, Esters such as butyl acetate, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cellosolves; non-protons such as dimethylformamide, dimethyl sulfoxide, hexamethyl phosphoramide There is a polar solvent, and the like. Among these, acetone, methyl amyl ketone, methyl ethyl ketone, tetrahydrofuran, methanol, ethanol, propanol, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and the like are preferable.

(3) Physical properties:
The polystyrene equivalent weight average molecular weight (hereinafter also referred to as “Mw”) of the resin (A) measured by gel permeation chromatography (GPC) is preferably 3000 to 100,000, and preferably 3000 to 40000. More preferably, it is 3000-25000. Moreover, ratio (Mw / Mn) of Mw of resin (A) and the number average molecular weight (henceforth "Mn") of polystyrene conversion measured by GPC is 1-5 normally, and 1-3 It is preferable that it is 1 and 2.5.

(Low molecular weight compounds containing acid dissociable groups)
In this specification, the acid dissociable group-containing low molecular weight compound has a molecular weight of 5000 or less, has at least two acid dissociable groups in its structure, and is located at a position where the distance between the acid dissociable groups is farthest. And a compound that passes through at least four bonding atoms excluding an acid dissociable group (hereinafter referred to as “compound (A ′)”).

  When the compound (A ′) has two acid-dissociable groups in its structure, it preferably passes through at least 10 bonding atoms excluding the acid-dissociable group, more preferably through at least 11, It is particularly preferable to pass 12 pieces. Further, when the structure has 3 or more acid-dissociable groups, it is preferable that at least 9 bonding atoms excluding the acid-dissociable group are passed, more preferably at least 10 are passed, and at least 11 are passed. It is particularly preferred. The upper limit of bond atoms excluding the acid dissociable group is preferably 50 or less, and more preferably 30 or less.

  Even when the compound (A ′) has 3 or more, preferably 4 or more acid dissociable groups, or 2 acid dissociable groups, the acid dissociable groups are separated from each other by a certain distance or more. If so, the dissolution inhibiting property for the alkali-soluble resin is remarkably improved. In addition, the distance between the acid dissociable groups in the compound (A ′) is indicated by the number of via-bonded atoms excluding the acid dissociable group. For example, in the case of the compounds represented by the following general formulas (A′-1) and (A′-2), the number of via bond atoms, which is the distance between the acid dissociable groups, is 4, respectively. In the case of the compound represented by A′-3), the number of via-bonding atoms is 12.

  In addition, the compound (A ′) may have a plurality of acid-dissociable groups on one benzene ring and is composed of a skeleton having one or two acid-dissociable groups on one benzene ring. It is preferred that Furthermore, the molecular weight of the compound (A ′) is 5,000 or less, preferably 500 to 4,000, and more preferably 1,000 to 2,500.

Compound (A '), the acid dissociable group, i.e., ^{-COO-A 0} group, a group containing ^{-O-B 0 group,} -R ^{0 -COO-A} 0 group or ^{-Ar-O-B 0} It is preferable to have a group represented by a group.

Here, R ⁰ represents a divalent or higher aliphatic hydrocarbon group or aromatic hydrocarbon group which may have a substituent. Ar represents a divalent or higher-valent aromatic hydrocarbon group which may have a monocyclic or polycyclic substituent. A ⁰ is —C (R ⁰¹ ) (R ⁰² ) (R ⁰³ ), —Si (R ⁰¹ ) (R ⁰² ) (R ⁰³ ), or —C (R ⁰⁴ ) (R ⁰⁵ ) —O—R ^06. The group represented by these is shown. B ⁰ represents a group represented by ^{A 0,} or ^{-CO-O-A 0.}

R ^{01 to} R ⁰⁵ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group (provided that at least two of R ^{01 to} R ⁰³ are groups other than hydrogen atoms). Is). R ⁰⁶ represents an alkyl group or an aryl group. Two of R ^{01 to} R ⁰³ may be bonded to form a cyclic structure. Moreover, two of R ^{04 to} R ⁰⁶ may be bonded to form a cyclic structure.

Among the groups represented by R ^{01 to} R ⁰⁵ , the alkyl group includes an alkyl having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, and a t-butyl group. Groups are preferred. Moreover, as a cycloalkyl group, C3-C10 cycloalkyl groups, such as a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, an adamantyl group, are preferable. Furthermore, as an alkenyl group, C2-C4 alkenyl groups, such as a vinyl group, a propenyl group, an allyl group, a butenyl group, are preferable. Moreover, as an aryl group, C6-C14 aryl groups, such as a phenyl group, a xylyl group, a toluyl group, a cumenyl group, a naphthyl group, an anthracenyl group, are preferable.

The substituents that R ⁰ and Ar may have include: hydroxyl group; halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; nitro group; cyano group; alkyl group; methoxy group, ethoxy group, hydroxy Alkoxy groups such as ethoxy group, propoxy group, hydroxypropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group and t-butoxy group; alkoxycarbonyl groups such as methoxycarbonyl group and ethoxycarbonyl group; benzyl group and phenethyl group Aralkyl group such as cumyl group; Aralkyloxy group; Acyl group such as formyl group, acetyl group, butyryl group, benzoyl group, cyanamyl group, valeryl group; Acyloxy group such as butyryloxy group; Alkenyl group; Vinyloxy group, propenyloxy group , Allyloxy group, butenyloxy group, etc. An aryloxy group such as a phenoxy group; an aryloxycarbonyl group such as a benzoyloxy group.

  As the acid dissociable group, a silyl ether group, a cumyl ester group, an acetal group, a tetrahydropyranyl ether group, an enol ether group, an enol ester group, a tertiary alkyl ether group, a tertiary alkyl ester group, Tertiary alkyl carbonate groups and the like. More preferred are tertiary alkyl ester groups, tertiary alkyl carbonate groups, cumyl ester groups, and tetrahydropyranyl ether groups.

Examples of the compound (A ′) include JP-A-1-289946, JP-A-1-289947, JP-A-2-2560, JP-A-3-128959, JP-A-3-158855, JP-A-3-158855. JP-A-3-179353, JP-A-3-191351, JP-A-3-200251, JP-A-3-200252, JP-A-3-200263, JP-A-3-200254, JP-A-3-200341. Japanese Patent Laid-Open No. 200225, Japanese Patent Laid-Open No. 3-259149, Japanese Patent Laid-Open No. 3-279958, Japanese Patent Laid-Open No. 3-279959, Japanese Patent Laid-Open No. 4-1650, Japanese Patent Laid-Open No. 4-1651, Japanese Patent Laid-Open No. 4-11260 JP-A-4-12356, JP-A-4-12357, JP-A-4-271349, JP-A-5-45869, JP-A-5 No. 158233, JP-A-5-224409, JP-A-5-257275, JP-A-5-297583, JP-A-5-303200, JP-A-5-341510, etc. A compound in which part or all of the phenolic hydroxyl group of a hydroxy compound is bonded with a —R ⁰ —COO—A ⁰ or —Ar—O—B ⁰ group and protected is included.

  In addition, examples of the compound (A ′) include a compound represented by the following general formula (A′-4).

（一般式（Ａ’−４）中、Ｒは、相互に独立に、水素原子、又は置換若しくは非置換の酸解離性基を示す。Ｘは、相互に独立に、炭素数１〜８の置換又は非置換のアルキレン基を示す。Ｚは、相互に独立に、炭素数１〜１０の置換若しくは非置換のアルキル基、炭素数２〜１０の置換若しくは非置換のアルケニル基、炭素数２〜１０の置換若しくは非置換のアルキニル基、炭素数７〜１０の置換若しくは非置換のアラルキル基、炭素数１〜１０の置換若しくは非置換のアルコキシ基、又は置換若しくは非置換のフェノキシ基を示す。ｑは、相互に独立に、０又は１である。）

(In the general formula (A′-4), R independently represents a hydrogen atom or a substituted or unsubstituted acid-dissociable group. X independently represents a substituent having 1 to 8 carbon atoms. Or Z represents an independently substituted alkylene group, each independently representing a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, or 2 to 10 carbon atoms. A substituted or unsubstituted alkynyl group, a substituted or unsubstituted aralkyl group having 7 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, or a substituted or unsubstituted phenoxy group. , Independently of one another, 0 or 1.)

2. Radiation sensitive acid generator:
The radiation-sensitive acid generator is a substance that generates an acid in the radiation-sensitive composition when the radiation-sensitive composition of the present invention is irradiated with an electron beam or radiation in a lithography process. The acid dissociable group in the acid dissociable group-containing compound is dissociated by the action of the acid generated from the radiation sensitive acid generator.

  Examples of the radiation sensitive acid generator include an onium salt, a diazomethane compound, and a sulfonimide compound (however, the compound represented by the general formula (1)) from the viewpoint of good acid generation efficiency, heat resistance, and the like. It is preferably at least one selected from the group consisting of: In addition, these may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of onium salts include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like. Among these, the onium salt represented by the general formula (4) is preferable.

In order to obtain good sensitivity, in the general formula (4), A ⁺ is preferably a sulfonium cation or an iodonium cation. Specific examples thereof include a sulfonium cation represented by the general formula (5) and an iodonium cation represented by the following general formula (13).

（一般式（１３）中、複数のＲ^９は、相互に独立に、置換されていてもよい炭素数１〜１０の直鎖状若しくは分岐状のアルキル基、又は置換されていてもよい炭素数６〜１８のアリール基を示す。但し、２つのＲ^９が相互に結合してヨウ素カチオンとともに環状構造を形成してもよい。）

(In the general formula (13), a plurality of R ⁹ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted, or an optionally substituted carbon number. 6 to 18 aryl groups, provided that two R ⁹ may be bonded to each other to form a cyclic structure together with an iodine cation.)

A monovalent onium cation moiety represented by A ⁺ is described in, for example, Advances in Polymer Sciences, Vol. 62, p. 1-48 (1984).

Specific examples of the monovalent anion represented by B ⁻ in the general formula (4) include the anions represented by the general formulas (B-1) and (B-2), and the following general formula (B -3) and anions represented by (B-4). Among these, the anions represented by the general formulas (B-1) and (B-2) are preferable.

（一般式（Ｂ−３）中、複数のＲ^１０は、相互に独立に、少なくとも１つのフッ素原子で置換された炭素数１〜２０のアルキル基を示す。但し、２つのＲ^１０が相互に結合して、少なくとも１つのフッ素原子で置換された員数６〜２０の環状構造を形成してもよい。一般式（Ｂ−４）中、複数のＲ^１１は、相互に独立に、少なくとも１つのフッ素原子で置換された炭素数１〜２０のアルキル基を示す。但し、いずれか２つのＲ^１１が相互に結合して、少なくとも１つのフッ素原子で置換された員数６〜２０の環状構造を形成し、残りの１つのＲ^１１が少なくとも１つのフッ素原子で置換された炭素数１〜２０のアルキル基であってもよい。）

(In the general formula (B-3), a plurality of R ^{10 s} each independently represent an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom, provided that two R ^{10 s} each other. It may combine to form a cyclic structure having 6 to 20 members substituted with at least one fluorine atom, wherein in the general formula (B-4), a plurality of R ¹¹ are independently of each other at least one 1 represents an alkyl group having 1 to 20 carbon atoms substituted with a fluorine atom, provided that any two R ¹¹ are bonded to each other to form a cyclic structure having 6 to 20 members substituted with at least one fluorine atom; And the remaining one R ¹¹ may be an alkyl group having 1 to 20 carbon atoms substituted with at least one fluorine atom.)

  Examples of the diazomethane compound include a compound represented by the following general formula (14).

（一般式（１４）中、複数のＲ^１２は、相互に独立に、１価の有機基を示す。）

(In the general formula (14), a plurality of R ¹² independently represent a monovalent organic group.)

In the general formula (14), examples of the monovalent organic group represented by R ¹² include an alkyl group, an aryl group, a halogen-substituted alkyl group, and a halogen-substituted aryl group. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group. -12 linear or branched alkyl groups can be mentioned. Specific examples of the aryl group include aryl groups having 6 to 22 carbon atoms such as a phenyl group, a tolyl group, a naphthyl group, and an anthryl group.

  Specific examples of the halogen-substituted alkyl group include groups in which at least one hydrogen atom in the above-described alkyl group is substituted with a halogen (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.). Specific examples of the halogen-substituted aryl group include groups in which at least one hydrogen atom in the above-described aryl group is substituted with a halogen (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.).

  Furthermore, examples of the sulfonimide compound include a compound represented by the following general formula (15).

（一般式（１５）中、Ｄは、２価の基を示す。Ｒ^１３は１価の有機基を示す。）

(In General Formula (15), D represents a divalent group. R ¹³ represents a monovalent organic group.)

  In the general formula (15), examples of the divalent group represented by D include a methylene group, an alkylene group, an arylene group, and an alkoxylene group. Specific examples of the alkylene group include linear or branched alkylene groups having 2 to 12 carbon atoms such as an ethylene group, a 1-methylethylene group, and an n-butylene group. Specific examples of the arylene group include arylene groups having 6 to 22 carbon atoms such as phenylene group, naphthylene group, methylphenylene group, ethylphenylene group, chlorophenylene group, bromophenylene group, and fluorophenylene group. Specific examples of the alkoxylene group include linear or branched alkoxylene groups having 2 to 12 carbon atoms such as an ethoxylene group, a propoxyxylene group, and a butylenexylene group.

In the general formula (15), examples of the monovalent organic group represented by R ¹³ include an alkyl group, an aryl group, a halogen-substituted alkyl group, and a halogen-substituted aryl group. These explanations can be applied as they are for the monovalent organic group represented as R ¹² in the general formula (14).

  The content of the radiation-sensitive acid generator is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the acid dissociable group-containing compound. . There exists a possibility that a sensitivity and developability may fall that content is less than 0.1 mass part. On the other hand, if it exceeds 40 parts by mass, transparency to radiation, pattern shape, heat resistance and the like may be reduced.

3. Compound represented by general formula (1):
The compound represented by the general formula (1) is a sulfonimide compound described in “I. Sulfonimide compound”.

  The content of the compound (C) is preferably 30 parts by mass or less, more preferably 5 to 25 parts by mass, and 5 to 20 parts by mass with respect to 100 parts by mass of the acid dissociable group-containing compound. More preferably it is. There exists a possibility that the resolution of the formed resist film may fall that content of a compound (C) is more than 30 mass parts. On the other hand, if it is less than 5 parts by mass, the resolution may be lowered.

4). solvent:
The radiation-sensitive composition of the present invention is usually used as a composition solution in which an acid-dissociable group-containing compound, a radiation-sensitive acid generator, and compound (C) are dissolved in a solvent.

  Examples of the solvent include linear or branched ketones, cyclic ketones, propylene glycol monoalkyl ether acetates, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate, and γ-butyrolactone. It is preferably at least one selected from the group.

  The amount of the solvent used is preferably such that the total solid concentration in the radiation-sensitive composition is 1 to 70% by mass, more preferably 1 to 15% by mass. The amount is more preferably 10% by mass.

  The composition solution when using the radiation-sensitive composition of the present invention comprises an acid-dissociable group-containing compound, a radiation-sensitive acid generator, a compound (C), and other components (excluding the solvent) as necessary. It is preferable to filter with a filter having a pore size of about 0.2 μm, for example, after being uniformly dissolved in the solvent so that the total solid content concentration falls within the above range.

5. Acid diffusion control agent:
The radiation-sensitive composition of the present invention may further contain an acid diffusion controller. The acid diffusion control agent has a function of controlling a diffusion phenomenon in the resist film of an acid generated from the radiation-sensitive acid generator by exposure and suppressing an undesirable chemical reaction in a non-exposed region.

  By containing such an acid diffusion control agent, the storage stability of the resulting radiation-sensitive composition is improved, and the resist pattern resulting from fluctuations in the holding time (PED) from after exposure to the subsequent heat treatment It is possible to suppress the change in the line width. Therefore, a radiation sensitive composition having extremely excellent process stability can be obtained.

  Examples of the acid diffusion controller include nitrogen-containing organic compounds. Examples of the nitrogen-containing organic compound include a compound represented by the following general formula (16) (hereinafter referred to as “nitrogen-containing compound (i)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “containing“ Nitrogen compound (ii) ”), polyamino compounds and polymers having 3 or more nitrogen atoms (hereinafter collectively referred to as“ nitrogen-containing compounds (iii) ”), amide group-containing compounds, urea compounds, nitrogen-containing complexes Examples include ring compounds.

（一般式（１６）中、複数のＲ^１４は、相互に独立に、水素原子、置換されていても良い直鎖状若しくは分岐状のアルキル基、シクロアルキル基、置換されていても良いアリール基、又は置換されていても良いアラルキル基を示す。）

(In the general formula (16), a plurality of R ¹⁴ are each independently a hydrogen atom, an optionally substituted linear or branched alkyl group, a cycloalkyl group, or an optionally substituted aryl group. Or an optionally substituted aralkyl group.)

  Examples of the nitrogen-containing compound (i) include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylamines such as triethanolamine; and aromatic amines.

  Examples of the nitrogen-containing compound (ii) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, and 4,4′-diaminodiphenylether. 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, , 4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, bis (2-dimethylaminoethyl) ) Ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-y Dazorijinon, 2 quinoxalinium linoleic, N, N, N ', there is N'- tetrakis (2-hydroxypropyl) ethylenediamine and the like.

  Examples of the nitrogen-containing compound (iii) include polymers of polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide, and the like.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt- Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-( -)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl Perazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′- Diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N′-di-t-butoxycarbonyl- 1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di -T-butoxycarbonyl-1,10-diaminodecane, N, N'-di-t-butoxycarbonyl-1,12-diaminododecane, N, '-Di-t-butoxycarbonyl-4,4'-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenz In addition to Nt-butoxycarbonyl group-containing amino compounds such as imidazole, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl), and the like.

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea. Etc.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine. 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2. 2.2] Octane and the like.

  In addition, a radiation sensitive composition may contain an acid diffusion control agent individually by 1 type or in combination of 2 or more types.

  The content of the acid diffusion controller is preferably 15 parts by mass or less, more preferably 0.001 to 10 parts by mass, and more preferably 0.005 to 100 parts by mass with respect to 100 parts by mass of the acid dissociable group-containing compound. 5 parts by mass is particularly preferable. There exists a possibility that the sensitivity of the formed resist film and the developability of an exposure part may fall that content of an acid diffusion control agent exceeds 15 mass parts. On the other hand, if it is less than 0.001 part by mass, the pattern shape and dimensional fidelity of the formed resist film may be lowered depending on the process conditions.

6). Other ingredients:
The radiation-sensitive composition of the present invention may further contain various additives such as a surfactant, a sensitizer, and an aliphatic additive as other components as necessary.

  A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like. Examples of such surfactants include nonionic surfactants such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, as well as 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), MegaFuck 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 may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, it is preferable that content of surfactant is 0.001-2 mass parts with respect to 100 mass parts of acid dissociable group containing compounds.

  A sensitizer absorbs the energy of radiation and transmits the energy to the radiation-sensitive acid generator, thereby increasing the amount of acid produced. The apparent sensitivity of the radiation-sensitive composition. Has the effect of improving. Examples of such sensitizers include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, and phenothiazines. In addition, these sensitizers may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, it is preferable that content of a sensitizer is 0.1-10 mass parts with respect to 100 mass parts of acid dissociable group containing compounds.

  Further, by blending a dye or a pigment, the latent image in the exposed area can be visualized, and the influence of halation during exposure can be reduced. Moreover, the adhesiveness of a resist film and a board | substrate can be improved by containing an adhesion aid.

The alicyclic additive is a component having an action of further improving dry etching resistance, pattern shape, adhesion to the substrate, and the like. Examples of such alicyclic additives include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t- Deoxycholic acid esters such as butoxycarbonylmethyl; lithocholic acid esters such as tert-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, and 3- (2-hydroxy-2,2-bis (trifluoromethyl) ) ethyl) tetracyclo ^(6.2.1.1 3,6 ^{.0 2,7)} there is a dodecane. In addition, these alicyclic additives may be used individually by 1 type, and may be used in combination of 2 or more type.

  It is preferable that content of an alicyclic additive is 0.5-20 mass parts with respect to 100 mass parts of acid dissociable group containing compounds. There exists a possibility that the heat resistance of the formed resist film may fall that content of this alicyclic additive exceeds 20 mass parts.

  In addition to these, an alkali-soluble polymer, a low-molecular alkali solubility control agent having an acid-dissociable protecting group, an antihalation agent, a storage stabilizer, an antifoaming agent, and the like can be contained.

(Method for forming resist pattern)
The radiation-sensitive composition of the present invention is useful as a material capable of forming a chemically amplified positive resist film. In the chemically amplified positive resist film, the acid-dissociable group in the acid-dissociable group-containing compound is dissociated by the action of the acid generated from the radiation-sensitive acid generator by exposure, and the acid-dissociable group-containing compound is alkalinized. It becomes soluble. That is, an alkali-soluble site is generated in the resist film. This alkali-soluble portion is an exposed portion of the resist, and this exposed portion can be dissolved and removed by an alkali developer. In this way, a positive resist pattern having a desired shape can be formed. This will be specifically described below.

  In order to form a resist pattern using the radiation-sensitive composition of the present invention, first, a resist film is formed using the radiation-sensitive composition of the present invention. As the radiation-sensitive composition, for example, as described above, after adjusting the total solid content concentration, a composition solution filtered with a filter having a pore size of about 0.2 μm can be used. A resist film is formed by applying this composition solution onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating or roll coating. Thereafter, in some cases, heat treatment (hereinafter referred to as “PB”) may be performed at a temperature of about 70 to 160 ° C. in advance.

  Next, the resist film is exposed so that a predetermined resist pattern is formed. Examples of radiation that can be used for this exposure include (extreme) far ultraviolet rays such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), EUV (extreme ultraviolet light, wavelength 13.5 nm, etc.), and synchro Examples include X-rays such as tron radiation, and charged particle beams such as electron beams. Moreover, exposure conditions, such as exposure amount, can be suitably selected according to the compounding composition of a radiation sensitive composition, the kind of additive, etc. This exposure can also be immersion exposure.

  After the exposure, heat treatment (hereinafter referred to as “PEB”) is preferably performed. This PEB makes it possible to smoothly dissociate the acid dissociable group of the acid dissociable group-containing compound. Although the heating conditions for PEB can be appropriately selected depending on the composition of the radiation-sensitive composition, it is preferably 30 to 200 ° C, more preferably 50 to 170 ° C.

  In the present invention, in order to maximize the potential of the radiation-sensitive composition, it is used, for example, as disclosed in Japanese Patent Publication No. 6-12452 (Japanese Patent Laid-Open No. 59-93448). An organic or inorganic antireflection film can also be formed on the substrate. Further, in order to prevent the influence of basic impurities contained in the environmental atmosphere, a protective film can be provided on the resist film as disclosed in, for example, JP-A-5-188598. These techniques can be used in combination.

  Next, a predetermined resist pattern is formed by developing the exposed resist film. Examples of the developer used for development include sodium hydroxide, potassium hydroxide, sodium carbonate, tetramethylammonium hydroxide, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5. An alkaline aqueous solution in which at least one alkaline compound such as diazabicyclo- [4.3.0] -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. Further, the developer is preferably pH 8 to 14, more preferably pH 9 to 14.

  Moreover, an organic solvent can also be added to the developing solution which consists of alkaline aqueous solution, for example. 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. These organic solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

  The blending amount of the organic solvent is preferably 100 parts by volume or less with respect to 100 parts by volume of the alkaline aqueous solution. If the blending amount of the organic solvent is more than 100 parts by volume, the developability is lowered, and there is a possibility that the remaining development in the exposed part increases. In addition, an appropriate amount of a surfactant or the like can be added to the developer composed of an alkaline aqueous solution. In addition, after developing with the developing solution which consists of alkaline aqueous solution, it can also wash with water and can be dried.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. “Parts” in Examples and Comparative Examples 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. In this embodiment, EB (electron beam) is used for exposure of the resist film. However, even when short wavelength radiation such as EUV is used, the basic resist characteristics are similar, and it is known that there is a correlation between them.

  [Weight average molecular weight (Mw) and number average molecular weight (Mn)]: GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column temperature : Measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C. Further, the degree of dispersion Mw / Mn was calculated from the measurement results.

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

[ ¹ H-NMR analysis]: Measured using a model “JNM-Delta400” manufactured by JEOL Ltd.

[Sensitivity (L / S) (μC / cm ² )]: A pattern (so-called “pattern”) including a line part having a line width of 150 nm and a space part (that is, a groove) having an interval of 150 nm formed by adjacent line parts. The exposure amount for forming a line-and-space pattern (1L1S) with a one-to-one line width was taken as the optimum exposure amount, and the sensitivity was evaluated based on this optimum exposure amount.

  [Nano edge roughness (nm)]: A line-and-space pattern (1L1S) having a designed line width of 150 nm is scanned with a scanning electron microscope for semiconductors (high-resolution FEB measuring device, trade name “S-9220”, Hitachi, Ltd.) (Manufactured by Seisakusho). Regarding the observed shape, as shown in FIG. 1, the difference between the line width at the most conspicuous portion of the unevenness generated along the lateral side surface 2 a of the line portion of the resist film formed on the silicon wafer 1 and the design line width 150 nm “ Nano edge roughness was evaluated by measuring “ΔCD” with CD-SEM (manufactured by Hitachi High-Technologies Corporation, “S-9220”). In addition, the unevenness | corrugation shown in FIG. 1 is exaggerated from actuality.

  [Resolution (L / S) (nm)]: For the line-and-space pattern (1L1S), the minimum line width of the line pattern resolved with the optimum exposure dose was taken as the resolution.

(Synthesis Example 1: Preparation of Resin (A-1))
56 g of p-acetoxystyrene, 44 g of a compound represented by the formula (M-1) (hereinafter also referred to as “compound (M-1)”), 4 g of azobisisobutyronitrile (hereinafter referred to as “AIBN”), and 1 g of t-dodecyl mercaptan was dissolved in 100 g of propylene glycol monomethyl ether, and then the polymerization was carried out for 16 hours while maintaining the reaction temperature at 70 ° C. in a nitrogen atmosphere. After the polymerization, the reaction solution was dropped into 1000 g of n-hexane to coagulate and purify the copolymer.

Next, 150 g of propylene glycol monomethyl ether was added to the copolymer again, and then 150 g of methanol, 35 g of triethylamine, and 7 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained copolymer was dissolved in 150 g of acetone, then dropped into 2000 g of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. Dried overnight. The obtained copolymer has Mw of 11000, Mw / Mn of 2.0, and as a result of ¹³ C-NMR analysis, it is derived from the repeating unit derived from p-hydroxystyrene and the compound (M-1). It was a copolymer having a content ratio (mol ratio) of the repeating unit of 65:35. Hereinafter, this copolymer is referred to as “resin (A-1)”.

(Example 1: Synthesis of compound (C))
A compound (40 mmol) represented by the following formula (C′-1) was dissolved in water and stirred for 30 minutes. Thereto was added an aqueous solution of a compound (30 mmol) represented by the following formula (C′-2), and the mixture was stirred for 1.5 hours. After adding 500 g of methylene chloride to the reaction solution and further stirring for 1 hour, the methylene chloride layer was recovered and washed 5 times with 500 g of water. Thereafter, methylene chloride was distilled off under reduced pressure and dried to obtain a compound.

¹ H-NMR of the obtained compound was measured. The measurement results are shown below. The measurement sample was prepared by dissolving the obtained compound (0.03 mmol) in deuterated dimethyl sulfoxide (1.0 ml).

¹ H-NMR (400 MHz, solvent DMSO-d6, internal standard TMS): δ (ppm) = 7.75-7.90 (15H, m), 5.25 (1H, s), 1.90 (3H, s).

^From the result of ¹ H-NMR, it was found that the structure of the obtained compound was a structure represented by the following formula (C-1). Hereinafter, this compound is referred to as “compound (C-1)”.

(Example 2)
100 parts of resin (A-1) prepared in Synthesis Example 1, 15 parts of acid generator (B-1), 5 parts of compound (C-1) synthesized in Example 1, acid diffusion controller (D-1) 2 parts, 1100 parts of solvent (E-1), and 2500 parts of solvent (E-2) are mixed, and the resulting mixture is filtered through a membrane filter having a pore size of 200 nm, whereby a composition of a radiation sensitive composition is prepared. A solution was prepared.

(Examples 3-4 and Comparative Examples 1-2)
Resin (A), acid generator (B), compound (C), acid diffusion controller (D), and solvent (E) were mixed in the amounts shown in Table 1, and the resulting mixture was mixed with pore size. The composition solution of each radiation sensitive composition was prepared by filtering with a 200 nm membrane filter.

  Details of the acid generator (B), the acid diffusion controller (D), and the solvent (E) are shown below.

(Acid generator (B))
(B-1): Compound represented by formula (B-1) (B-2): Compound represented by formula (B-2)

(Acid diffusion control agent (D))
(D-1): Tri-n-octylamine

(Solvent (E))
(E-1): Ethyl lactate (E-2): Propylene glycol monomethyl ether acetate

(Evaluation of radiation-sensitive composition)
Within the trade name “Clean Track ACT-8” manufactured by Tokyo Electron Co., Ltd., a composition solution of a radiation sensitive composition was spin coated on a silicon wafer, and then PB (heat treatment) was performed under the conditions shown in Table 2. A resist film having a thickness of 50 nm was formed. Thereafter, the resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (manufactured by Hitachi, Ltd., model “HL800D”, output: 50 KeV, current density: 5.0 amperes / cm ² ). After the electron beam irradiation, PEB was performed under the conditions shown in Table 2. Thereafter, development was performed by a paddle method at 2.degree. C. for 1 minute using a 2.38% tetramethylammonium hydroxide aqueous solution. Thereafter, it was washed with pure water and dried to form a resist pattern. An evaluation test was performed on the resist pattern thus formed. The evaluation results are shown in Table 2.

  As can be seen from Table 2, the radiation sensitive compositions of Examples 2 to 4 containing the compound (C-1) are compared to the radiation sensitive compositions of Comparative Examples 1 and 2 not containing the compound (C). It is possible to form a chemically amplified positive resist film that is sensitive to electron beams, has low roughness, is excellent in sensitivity, and can form fine patterns with high accuracy and stability. it can. In particular, the radiation-sensitive compositions of Examples 3 to 4 containing the compound (C-1) and not containing the acid diffusion controller (D) include the compound (C-1) and the acid diffusion controller (D). Compared with the radiation-sensitive composition of Example 2 contained, the sensitivity was particularly excellent.

  The radiation-sensitive composition of the present invention is not only excellent in the resolution of the line and space pattern at the time of resist pattern formation, but also excellent in nano edge roughness, so it is useful for fine pattern formation by EB, EUV and X-rays. is there. Therefore, the radiation-sensitive composition of the present invention is extremely useful as a material capable of forming a chemically amplified resist for manufacturing semiconductor devices, which is expected to be further miniaturized in the future.

1; silicon wafer; 2; resist pattern; 2a; lateral side of resist pattern.

Claims (3)

A sulfonimide compound represented by the following general formula (1- a );
An acid dissociable group-containing compound;
A radiation-sensitive composition comprising a solvent.

(In the general formula (1- a ), M ⁺ represents a monovalent onium cation. R ^x represents a linear or branched alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group, an acyl group. Group represents an alicyclic hydrocarbon group, and x represents an integer of 0 to 2. ) The acid-labile group-containing compound is a resin having at least one repeating unit of a repeating unit represented by the following general formula (2) and a repeating unit represented by the general formula (3). The radiation-sensitive composition as described in 1.

(In General Formula (2), R ¹ represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. A plurality of R ² are independently monovalent from 4 to 20 carbon atoms. An alicyclic hydrocarbon group, or a linear or branched alkyl group having 1 to 4 carbon atoms, provided that any two R ² are bonded to each other, together with the carbon atom to which each is bonded. (An alicyclic hydrocarbon group may be formed.)

(In General Formula (3), R ¹ represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group. A plurality of R ² are independently monovalent from 4 to 20 carbon atoms. An alicyclic hydrocarbon group, or a linear or branched alkyl group having 1 to 4 carbon atoms, provided that any two R ² are bonded to each other, together with the carbon atom to which each is bonded. (An alicyclic hydrocarbon group may be formed.) The radiation sensitive composition of Claim 1 or 2 which further contains the radiation sensitive acid generator containing the onium salt represented by following General formula (4).
A ⁺ B ⁻ : (4)
(In the general formula (4), A ⁺ represents a monovalent onium cation. B ⁻ represents a monovalent anion represented by the following general formula (B-1) or the following general formula (B-2). Show.)
R ³ C _n F _2n SO ₃ ⁻ : (B-1)
R ⁴ SO ₃ ⁻ : (B-2)
(R ³ in the general formula (B-1) and R ⁴ in (B-2) represent a fluorine atom or a hydrocarbon group having 1 to 12 carbon atoms. In the general formula (B-1), n represents an integer of 1 to 10.)

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