JPH11271974A - Novel acrylic monomer, novel acrylic polymer, resist composition and pattern forming method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resist compsn. which can be exposed even at short wavelength, gives stable pattern characteristics and is excellent in dry etching resistance and transparency by using a specified monomer. SOLUTION: The resist compsn. contains a polymer of a monomer represented by the formula and an acid generating agent. In the formula, R is H or 1-3C optionally substd. alkyl, R' is 1-6C optionally substd. alkyl and Z is plural atoms required to complete an optionally substd. alicyclic hydrocarbon group having at least two norbornane skeletons in combination with C. The resist compsn. may further contain other additives such as amines. When amines are used, resist characteristics such as resolution, pattern shape and mask linearity can be enhanced even if active light of short wavelength such as ArF excimer laser is used as a light source for exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel monomer, a polymer obtained by polymerizing the monomers or the monomer and another polymerizable compound, and a polymer containing two norbornane skeletons which are eliminated by reacting with an acid. The present invention relates to a resist composition containing the same and a pattern forming method using the resist composition.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a step of forming a photosensitive film by applying a resist on the surface of a silicon wafer, a step of irradiating light to form a latent image, and then developing the latent image to form a negative or positive The step of obtaining an image by a lithography technique for forming an image is included. By the way, IC, LS
I. Furthermore, as semiconductors become more highly integrated, denser, smaller, and faster in VLSIs, the demand for fine processing of devices increases. At present, technology for forming fine patterns of 0.5 μm or less is required. I have. However, it is extremely difficult to form such a fine pattern by conventional lithography using near ultraviolet light or visible light, and the yield is significantly reduced. For this reason, instead of conventional lithography using near-ultraviolet light having a wavelength of 350 to 450 nm, a KrF excimer laser with a short wavelength of far ultraviolet light (short-wave ultraviolet light) and a wavelength of 248 nm is used in order to increase the resolution of exposure.
A lithography technique using an ArF excimer laser with a wavelength of 193 nm is being studied. In conventional lithography using near-ultraviolet light, an alkali-soluble phenol resin such as a novolak resin is used as a base polymer. Although this resin has good transparency to near ultraviolet light having a wavelength of 350-450 nm, it absorbs far ultraviolet light and vacuum ultraviolet light having shorter wavelengths, and thus has poor transparency. For light of shorter wavelength such as laser light, the transmittance is extremely deteriorated because the benzene ring absorbs light, so that there is a problem that sufficient sensitivity cannot be obtained and the pattern shape is poor. Therefore, a resin excellent in transparency at a short wavelength is required, and use of a methacrylate copolymer resin having no benzene ring is being studied. However, there is a problem that the dry etching resistance is significantly reduced unless a benzene ring is contained in the resin. In order to solve this problem, a polymer having an adamantane skeleton or a norbornane skeleton in an ester portion has been studied (Japanese Patent Laid-Open No. Hei 4-39).
665, JP-A-5-257284, JP-A-5-265212, and JP-A-7-234511. However, a polymer having an adamantane skeleton has a problem in that the resist is distorted during development and cracks and peeling of a pattern are likely to occur, and a polymer having a norbornane skeleton has a problem that its dry etching resistance is not sufficient.

[0003]

Based on such prior art, the present inventors have conducted intensive studies to obtain a new resist composition capable of short-wavelength exposure, and as a result, have found that a polymer having a certain type of norbornane skeleton bonded thereto. Can be exposed even at short wavelengths and show not only stable pattern characteristics, but also excellent dry etching resistance and transparency.
The present invention has been completed.

[0004]

According to the present invention, there is provided a novel monomer represented by the following formula (1).

[0005]

Embedded image (Wherein, R is a hydrogen atom or an optionally substituted alkyl group having 1-3 carbon atoms; R ′ is 1-6 carbon atoms)
Is an optionally substituted alkyl group; and Z is a plurality of atoms necessary to complete an optionally substituted alicyclic hydrocarbon group having at least two norbornane skeletons together with the described C. According to the present invention, a novel polymer having a structural unit represented by the following formula (2) is provided.

[0006]

Embedded image (Wherein, R is a hydrogen atom or an optionally substituted alkyl group having 1-3 carbon atoms; R ′ is 1-6 carbon atoms)
Is an optionally substituted alkyl group; and Z is a plurality of atoms necessary to complete an optionally substituted alicyclic hydrocarbon group having at least two norbornane skeletons together with the described C. Represents 2 to 100,000
Further, according to the present invention, it comprises a polymer containing a structural unit containing a group capable of reacting with an acid represented by the following formula (3) and leaving, and an acid generator. Provided is a resist composition, a pattern forming method including a step of applying the resist composition on a substrate and a step of exposing using a light source having a wavelength of 180 to 250 nm.

[0007]

Embedded image Wherein R ′ is an optionally substituted alkyl group having 1-6 carbon atoms; Z is at least 2
Represents a plurality of atoms necessary for completing an optionally substituted alicyclic hydrocarbon group having a norbornane skeleton)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION (Monomer) The present invention relates to a novel monomer represented by the following formula (1), and this monomer is suitably used, for example, as a raw material for synthesizing a resist polymer.

[0009]

Embedded image (Wherein, R is a hydrogen atom or an optionally substituted alkyl group having 1-3 carbon atoms; R ′ is 1-6 carbon atoms)
Is an optionally substituted alkyl group; and Z is a plurality of atoms necessary to complete an optionally substituted alicyclic hydrocarbon group having at least two norbornane skeletons together with the described C. Represents)

R In the above formula (1), R is preferably a hydrogen atom,
It is a methyl group, an ethyl group or an n-propyl group, and more preferably a hydrogen atom or a methyl group. Although the substituent of R is not particularly limited, suitable substituents include a fluorine atom,
A halogen atom such as a chlorine atom, a bromine atom and an iodine atom; an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group and a t-butyl group; a methoxy group, an ethoxy group, an isopropoxy group and a t-butoxy group And an alkoxy group having 1 to 4 carbon atoms such as a group. When used for resist applications, those not substituted are preferred in order to enhance the transparency of the resist composition at the exposure wavelength and because the production is simple.

R ′ In the above formula (1), R ′ is preferably a methyl group, an ethyl group, an n-propyl group, an n-butyl group,
More preferred are a methyl group and an ethyl group. The substituents for R ′ are the same as those described as the substituents for R.

The ring structure composed of C and Z The ring structure composed of C and Z in the above formula (1) is preferably represented by the following formula (4).

[0013]

Embedded image Wherein m and q are 0, 1, 2 or 3; n
Is 0 or 1, provided that m + q ≧ 1; p
Is 0 or 1; R ¹ to R ²⁰ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted hydrocarbon group, an alkoxy group, an alkylcarbonyloxy group,
A cyano group or a silyl group; provided that R ¹⁷ , R ¹⁸ , R
R ¹⁹ and R ²⁰ or R ¹⁸ and R ¹⁹ may be bonded to each other to form an optionally substituted alkylidene group;
¹⁸ and carbon in the R ¹⁹ - carbon atoms in the ring structure which bond to bond may form a carbon-carbon double bond) in the formula, the above-mentioned R 'is substituted.

M , n, p, q As described in the definition of m, n, p, and q in the above formula (4), the ring structure composed of C and Z has 2 to 5 norbornane skeletons. , Preferably 2-3, more preferably 2. These norbornane skeletons may be adjacent to each other or may have a 5-membered or 6-membered alicyclic skeleton interposed therebetween. More specifically, m + q = 1-4, more preferably m + q = 1-2, and still more preferably m + q = 1, n is 0 or 1, and p is 0 or 1.

R ¹ -R ²⁰ As described in the above formula (4), R ¹ to R ²⁰ each independently represent a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group, an alkoxy group, an alkyl group, It is a carbonyloxy group, a cyano group or a silyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The hydrocarbon group preferably includes a chain or cyclic hydrocarbon group having 1 to 20 carbon atoms; more preferably, a chain having 1 to 20 carbon atoms, preferably 1 to 10, and more preferably 1 to 6 carbon atoms. Alkyl group; having 2-20 carbon atoms, preferably 2-10 carbon atoms, more preferably 2 carbon atoms.
A chain alkenyl group having -6; a cyclic alkyl group having 3-15, preferably 3-8, and more preferably 5-6 carbon atoms; an aryl group having 6-12, preferably 6-8, and more preferably 6 carbon atoms Is mentioned. The alkoxy group has 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 6 carbon atoms.
A chain alkoxy group. Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group,
1-carbon atoms such as an ethylcarbonyloxy group, a propylcarbonyloxy group, and an isopropylcarbonyloxy group;
6 lower alkylcarbonyloxy groups. Examples of the alkylidene group include lower alkylidene groups having 1 to 6 carbon atoms, such as a methylidene group, an ethylidene group, a propylidene group, and an isopropylidene group. Among them, a hydrogen atom and a hydrocarbon group are preferable as R ^{1 to} R ²⁰ , and a hydrogen atom and a chain alkyl group are more preferable. The substituents of the hydrocarbon group, the alkoxy group, the alkylcarbonyloxy group, the cyano group, the silyl group and the alkylidene group are the same as those described as the substituent of R.

Preferred basic skeleton of the ring structure represented by the basic skeleton above formula (4) is as follows. (I) tetracyclo [4.4.0.1 ^2.5. 1 ^7.10 ]-
3-dodecyl skeleton,

[0017]

Embedded image (Ii) pentacyclo [7.4.0.1 ^2.5 .
^19.12 . 0 ^8.13 ] -3-pentadecyl skeleton,

[0018]

Embedded image (Iii) pentacyclo [8.4.0.1 ^{2.5. 19.12} .
0 ^8.13 ] -3-hexadecyl skeleton,

[0019]

Embedded image (Iv) Pentacyclo [6.5.1.1 ^3.6 . 0 ^2.7 .
0 ^9.14 ] -4-pentadecyl skeleton,

[0020]

Embedded image (V) Pentacyclo [6.6.1.1 ^3.6 . 0 ^2.7 . 0
^9.14 ] -4-Hexadecyl skeleton,

[0021]

Embedded image (Vi) Hexacyclo [6.6.1.1 ^3.6 .
1 ^10.13 . 0 ^2.7 . ^09.14 ] -4-heptadecyl skeleton,

[0022]

Embedded image(Vii) heptacyclo [8.7.0.1^2.9. 1^4.7.
1^11.17. 0^3.8. 0 ^12.16] -5-eicosyl skeleton,

[0023]

Embedded image (Viii) Heptacyclo [8.8.0.1 ^2.9 .
1 ^4.7 . 1 ^11.17 . 0 ^3.8 . 0 ^12.16 ] -5-eicosyl skeleton.

[0024]

Embedded image

[0025] These groups, specifically, unsubstituted tetracyclo [4.4.0.1 ^{2. 5.} 1 ^7.10 ] -3-
Dodecyl group; 3-position is monomethyl-substituted, monoethyl-substituted,
Mono-n- propyl-substituted or mono-n- butyl-substituted tetracyclo [4.4.0.1 ^2.5. 1 ^7.10] -3-dodecyl group; 4-position monomethyl substituted, monoethyl substituted, mono-n- propyl-substituted or mono-n- butyl-substituted tetracyclo [4.4.0.1 ^2.5. 1 ^7.10] -3-dodecyl group; 9-position monomethyl substituted, monoethyl substituted, mono-n- propyl-substituted or mono-n- butyl-substituted tetracyclo [4.4.0.1 ^2.5. 1 ^7.10] -3-dodecyl group; 3-position is the monomethyl substituted, tetracyclo [4.4.0.1 ^2.5 11-position is dimethyl substituted.
^17.10 ] -3-dodecyl group; tetracyclo [3.
4.0.1 ^2.5 . 1 ^7.10] -3-dodecyl group, the 3-position is mono-n- propyl-substituted, tetracyclo [4.4.0.1 ^{2. 5} 11-position is dimethyl substituted. 1 ^7.10 ] -3-
Dodecyl group; tetracyclo [4.4.0.1 in which 3-position is mono-n-butyl-substituted and 11-position is dimethyl-substituted
^2.5 . 1 ^7.10] -3-dodecyl group; 2-position is the monomethyl substituted, tetracyclo [4.4.0.1 ^2.5 11-position is dimethyl substituted. ^17.10 ] -3-dodecyl group; 2
Tetracyclo [4.4.0.1 ^2.5 . 1 ^7.10 ] -3-
Dodecyl group, 3-position is mono-n-propyl substituted, 11
Tetracyclo [4.4.0.1 substituted at the dimethyl position
^2.5 . 1 ^7.10] -3-dodecyl group; 2-position is mono-n- butyl-substituted, tetracyclo [4.4.0.1 ^2.5 11-position is dimethyl substituted. ^17.10 ] -3-dodecyl group;
Unsubstituted pentacyclo [6.5.1.1 ^3.6 . 0 ^2.7 .
0 ^9.13 ] -4-pentadecyl group; pentacyclo [6.5.1.1] substituted at the 3-position with monomethyl, monoethyl, mono-n-propyl or mono-n-butyl.
^3.6 . 0 ^2.7 . 0 ^9.13 ] -4-pentadecyl group; pentacyclo [6. Monosubstituted, monoethyl-substituted, mono-n-propyl-substituted or mono-n-butyl-substituted 2-position];
5.1.1 ^3.6 . 0 ^2.7 . 0 ^9.14] -4-pentadecyl group; unsubstituted pentacyclo [6.6.1.1 ^3.6. 0
^2.7 . 0 ^9.14 ] -4-hexadecyl group; pentacyclo [6.6.l. 4-substituted mono-, mono-, mono-n-propyl- or mono-n-butyl-substituted 4-position;
1 ^3.6 . 0 ^2.7 . 0 ^9.14] -4-hexadecyl; 3-position monomethyl substituted, monoethyl substituted, pentacyclo [6.6.1.1 ^3.6 mono n- propyl substituted or mono-n- butyl-substituted 14-position is dimethyl substituted. 0 ^2.7 .
^09.14 ] -4-hexadecyl group.

Particularly Preferred Monomers Some of the particularly preferred monomers of the present invention are listed below, but the present invention is not limited to these examples.

[0027]

Embedded image

Method for synthesizing monomer The monomer of the present invention can be synthesized according to a conventional method. An example is given below.

[0029]

Embedded image

Reaction conditions (1) In the above synthesis method (1), the upper reaction and the middle reaction were respectively performed by ORGANIC SYNTHESE.
SP852, R.P. L. Snowden, Helv. C
him. Acta 66, 1031 (1983). For the lower reaction, 1 and 2 are dissolved in an organic solvent, and preferably triethylamine, tri-
A tertiary amine such as n-butylamine or pyridine is added, and the reaction temperature is -100C to 50C, preferably -50C.
-30 ° C, more preferably -30 ° C-20 ° C, 1-4
8 hours, preferably 2 to 24 hours, more preferably 3 to
By reacting for 12 hours, 3 can be obtained. Examples of the organic solvent include dichloromethane, chloroform, carbon tetrachloride, benzene, toluene, xylene, tetrahydrofuran, dioxane and the like. Among them, dichloromethane is preferable in consideration of the subsequent extraction step. The reaction charge ratio (molar ratio) of 1 and 2
1 : 2 is 1: 5 to 5: 1, preferably 1: 3 to 3:
1, more preferably 1: 2 to 2: 1.

[0031]

Embedded image

Reaction conditions (2) In the above synthesis method (2), the reaction in the upper stage is, as described above, ORGANIC SYNTHESES P8
52. For the middle reaction, 4 and methyllithium were dissolved in an organic solvent, and the reaction temperature was -1.
The reaction is performed at 00C to 20C, preferably -50C to 10C, more preferably -30C to 0C, for 30 minutes to 24 hours, preferably 45 minutes to 12 hours, more preferably 1 hour to 8 hours. Thereby, 5 can be obtained. Examples of the organic solvent include tetrahydrofuran, dioxane, ether, benzene, toluene and the like, and preferred is tetrahydrofuran. In addition, the reaction charge ratio (molar ratio) of 4 and methyllithium 4 : CH ₃ Li is
The ratio is 1: 5 to 1: 1, preferably 1: 3 to 1: 1, and more preferably 1: 2 to 1: 1. For the lower reaction,
5 and 6 were dissolved in an organic solvent, and the reaction temperature was -100 ° C.
By reacting at -50 ° C, preferably -50 ° C to 30 ° C, more preferably -30 ° C to 20 ° C, for 30 minutes to 24 hours, preferably 45 minutes to 12 hours, more preferably 1 hour to 8 hours. , 7 can be obtained. Examples of the organic solvent include tetrahydrofuran, dioxane, ether, benzene, toluene and the like, and preferred is tetrahydrofuran. The reaction charging ratio of 5 and 6 (molar ratio) 5: 6, 1: 5 to 5: 1, preferably 1: 3 to 3: 1, more preferably 1: 2 to 2: 1.

(Polymer) The present invention also relates to a polymer having a structural unit represented by the formula (2). This polymer may contain other structural units in addition to the structural unit represented by the formula (2). The other structural unit is not particularly limited as long as it is a structural unit derived from a monomer polymerizable with the monomer represented by the formula (1), and is removed by reacting with an acid other than the formulas (3) and (4) described below. Examples include a structural unit having a leaving group and a structural unit having a group which does not leave by reacting with an acid. The method for preparing the polymer is not particularly limited, but a method for producing a polymer for a resist composition described below is preferable. However, the monomer represented by the formula (1) is necessarily used as the monomer to be used.

(Resist Composition) The present invention also relates to a structural unit containing a group capable of leaving upon reaction with an acid represented by the formula (3), preferably the formula (4) (hereinafter sometimes referred to as a structural unit I). ) And an acid generator (acid generating compound; PAG). Structural Unit I Structural unit I is a compound represented by the formula (3), preferably an LG having a group (LG) which is eliminated by reacting with an acid represented by the formula (4): 3), preferably having a group represented by the formula (4). Equation (3) and Equation (4)
Is as described above.

The structural unit I containing the structure LG preferably has a structure represented by the following formula (5).

[0036]

Embedded image

M In the above formula (5), M is a unit forming the main chain of the polymer, and is represented by the following formula (6) or (7), preferably represented by the following formula (6) .

[0038]

Embedded image (Wherein, R ²¹ and R ²² are the same or different and are each a hydrogen atom; a lower alkyl group which may be substituted or -CO
Groups represented by R ²⁴ (R ²⁴ is optionally substituted lower alkoxy group, or for example a phenoxy group, an aryloxy group such as a benzyl group), R ²³ is a hydrogen atom;
Represents a halogen atom or an optionally substituted lower alkyl group)

R^{twenty one}And R^{twenty two}Is preferably a hydrogen atom
Or an optionally substituted alkyl group having 1-4 carbon atoms
And more preferably a hydrogen atom or a methyl group.
You. R ^{twenty three}Is preferably a hydrogen atom or a substituted
Alkyl groups having a good carbon number of 1-4 are more preferable.
Is a hydrogen atom or a methyl group. R^{twenty four}Is preferably
An alkoxy group having 1 to 4 carbon atoms which may be substituted;
You. The same as the substituents described above.

[0040]

Embedded image (Wherein, R ²³ is the same as described above)

Specific examples of preferred formula (6) include units represented by the following formulas (8) and (9), and particularly preferred is a unit represented by the formula (8). Wherein R ²³ and R
²⁴ is the same as above.

[0042]

Embedded image

[0043]

Embedded image

B In the above formula (5), B is a single bond or a divalent organic group having 1 to 10 carbon atoms. Specific examples of the divalent organic group of B include methylene, ethylene, propane-1,3-diyl,
Propane-1,2-diyl, butane-1,4-diyl,
Butane-2,2-diyl, pentane-1,5-diyl,
Chain or cyclic optionally substituted alkylene such as hexane-1,6-diyl, cyclopentylene, cyclohexylene, 2-methylcyclohexylene; vinylene, propenylene, butynylene, hexynylene, 2-chloropentynylene , 3-ethylhexenylene, cyclohexenylene, 2-chlorocyclohexenylene, -CH =
_{CHCH = CH -, - CH 2} C = CHCH 2 CH = C
Linear or cyclic alkenylene which may be substituted, such as H-, -CCl = CH-CH = CCl-; phenylene which may be substituted; and a divalent organic group obtained by combining these. However, an organic group containing a benzene ring can be present in a range that does not adversely affect the transparency of the resist. B is a single bond, alkylene,
Alkenylene is preferred, and a single bond is particularly preferred.

A In the above formula (5), A is a divalent organic group having a bond that is cleaved by reacting with an acid. Chemically amplified resist composition containing 0.01 to 50 parts by weight, preferably 0.2 to 30 parts by weight, more preferably 0.5 to 5 parts by weight of a photoacid generator per 100 parts by weight of a polymer Is an acid generated by exposure to excimer laser light. Preferred photoacid generators include triphenylsulfonium trifluoromethanesulfonate, and preferred excimer laser light is a KrF excimer laser or an ArF excimer laser, more preferably an ArF excimer laser. Specific examples include a carbonyloxy group, an oxycarbonyloxy group, a sulfonyl group, an amide group, and a phenoxy group, and preferably a carbonyloxy group and an oxycarbonyloxy group.

LG In the above formula (5), LG is as described in relation to formulas (3) and (4). The LG of the present invention is characterized by having at least two norbornane skeletons in its structure. Since it does not contain a benzene ring, it has good transmittance for short wavelengths, and can form a fine pattern even when using short wavelength active light such as an ArF excimer laser. In addition, the transmittance is more excellent than that having an adamantane skeleton, and by having at least two norbornane skeletons, the dry etching resistance is more excellent than that having one adamantane skeleton. Have. Further, each norbornane skeleton has two rings, and the rigidity is reduced as compared with the adamantane skeleton having three rings.
The distortion applied to the resist film during development can be reduced, and cracks and peeling of the pattern can be prevented. The greater the number of norbornane skeletons, the better the dry etching resistance. However, the number of norbornane skeletons is preferably 2-3 because the solubility in an alkaline developer becomes less during development and the strain on the resist film increases. Yes, and more preferably two.

Other Structural Units In addition to the structural units I described above, the polymer of the present invention reacts with an acid other than those of the formulas (3) and (4) and is eliminated in order to enhance the sensitivity and resolution of the resist. A structural unit having a group (P *) (hereinafter sometimes referred to as a structural unit II) and / or a structural unit having a group (Q) which is not desorbed by reacting with an acid in order to enhance adhesion between a resist and a substrate; (Hereinafter may be referred to as a structural unit III).

Structural Unit II The structural unit II has a group (P *) which reacts with an acid other than the formulas (3) and (4) to leave. P * P * is a group other than the above-described LG, and is an organic group which is eliminated by reacting with an acid. More specifically,
No. 0, Japanese Patent Publication No. 5-69420, tertiary alkyl group; substituted allyl group; pyranyl group such as 3-methylpyranyl group; cyclic ether group such as tetrahydrofuranyl group and tetrahydropyranyl group; oxocyclohexyl group and the like. Groups having a cyclic ketone structure;
And the group having a lactone structure described in Japanese Patent Publication No. 7 (1994) -78, and the like.

Specific examples of the tertiary alkyl group include t
-Butyl group, t-amyl group and the like.

The substituted allyl group includes a group represented by the following formula (10).

[0051]

Embedded image (Wherein, R ²⁵ is each independently a hydrogen atom; a halogen atom; a nitro group; a cyano group; an optionally substituted alkyl group, alkenyl group or alkadienyl group having 1 to 12 carbon atoms). , Preferably a methyl group, an ethyl group,
An isopropyl group, a t-butyl group and the like; an alkenyl group is preferably a vinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a 3-butenyl group,
Pentenyl group, 2-pentenyl group, 4-pentenyl group,
A hexenyl group and the like; an alkadienyl group is preferably a 1,2-propadienyl group, a 1,3-butadienyl group, a 2,3-butadienyl group, a 1,3-pentadienyl group, a 2,3-pentadienyl group, , 4-pentadienyl group and the like. The substituents are the same as those described as the substituents for R.

The group having a lactone structure is represented by the following formula (1)
The group shown by 1) is mentioned.

[0053]

Embedded image (Wherein, R ²⁶ is an optionally substituted alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 4). As the alkyl group, preferably a methyl group, an ethyl group, or an n-
A propyl group, an n-butyl group and the like; n is preferably 1 or 2. The substituents are the same as those described as the substituents for R.

The structural unit II preferably has the following formula (12)
It has a structure shown by.

[0055]

Embedded image (Wherein, M, B and A are as defined above).

Structural Unit III The structural unit III has a group (Q) which does not leave upon reaction with an acid. Q Q may be any group other than -A-LG or -AP * described above, and is preferably a hydroxyl group; a carboxyl group; a cyano group; a -CONH ₂ group; a formyl group; An oxy group, a carbonyloxy group, an oxycarbonyloxy group,
It is a group selected from the group consisting of a cyclic group consisting of any one of carbonyloxycarbonyl groups and alkylene.
The substituents are the same as those described as the substituents for R.

The structural unit III preferably has the following formula (1)
It has the structure shown in 3).

[0058]

Embedded image (Wherein, M and B are the same as described above)

[0059] show some preferred polymer structures of the present invention having the structural unit polymer structure above below. Wherein R ²³ , R ′, Z,
B, A, P * and Q are as described above.

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

In the above polymer, the structural unit I
The ratio (mol%) to other structural units (total of structural units II and III) is 100: 0 to 20:80,
Preferably 90:10 to 30:70, more preferably 7
0:30 to 40:60. The presence of another unit is preferred in terms of sensitivity and resolution. The ratio (mol%) of the structural unit II to the structural unit III is from 10:90 to 90:
10, preferably 20:80 to 80:20, more preferably 30:70 to 70:30.

The weight average molecular weight (Mw; hereinafter, referred to as molecular weight) is usually from 2,000 to 50,000, preferably from 3,000 to 30,000. Dispersion (Mw / M
n) is 5.0 or less, preferably 4.0 or less. If the weight average molecular weight (Mw) and the degree of dispersion (Mw / Mn) are too large, the solubility of the polymer in the resist solvent is reduced,
When the resist is applied, the resist film tends to be clouded or the resist characteristics such as sensitivity and resolution tend to decrease.
If the weight average molecular weight (Mw) is too small, the resist film tends to become brittle and the heat resistance tends to decrease. In addition,
The weight average molecular weight (Mw) and the number average molecular weight (Mn) are a weight average molecular weight in terms of polystyrene and a number average molecular weight in terms of polystyrene measured by gel permeation chromatography in a tetrahydrofuran solvent using a refractometer (RI).

The monomer used for the production of the polymer is a monomer that gives any necessary unit among the above-mentioned structural units, and it is preferable that each of the monomers has a high purity of 95% or more, more preferably 97% or more. If the purity of the monomer is too low, the weight average molecular weight (Mw) and the degree of dispersion (Mw / Mn) of the resulting copolymer will increase, and the resist properties such as sensitivity and resolution will decrease. The method for purifying the monomer is not particularly limited, and examples thereof include various methods such as fractional distillation, fractional precipitation, fractional crystallization, solvent extraction, and adsorption chromatography. One component of the preferred monomer is the acrylic monomer of the present invention.

The polymer is prepared by dissolving the above-mentioned monomer components in an organic solvent, and reacting the mixture at a polymerization temperature of 40-45 in the presence of a polymerization initiator.
150 ° C., preferably 60-90 ° C., polymerization time 1-2
It can be obtained by reacting for 4 hours, preferably 3 to 15 hours. Examples of the organic solvent include ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene and toluene; ketones such as acetone and methyl ethyl ketone; methyl halides such as carbon tetrachloride, chloroform and methylene chloride; Formamide, dimethyl sulfoxide and the like can be mentioned. These organic solvents can be used alone or in combination of two or more.
Among these, ethers are particularly preferred.

Examples of the polymerization initiator include benzoyl peroxide, t-butyl hydroperoxide, and di-t-peroxide.
Peroxides such as butyl and cumene hydroperoxide; persulfates such as potassium persulfate and ammonium persulfate; chlorides such as aluminum chloride, stannic chloride and titanium tetrachloride; alkali metals such as n-butyllithium and sodium naphthalene Salts: 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4
Azo compounds such as dimethylvaleronitrile), dimethyl-2,2'-azobisisobutyrate, 4,4'-azobis (4-cyanopentanoic acid) and azobiscyclohexanecarbonitrile; 2,2'- Azobis (2-
Amidine compounds such as aminodipropane) dihydrochloride and 2,2′-azobis (N, N′-dimethyleneisobutylamidine) dihydrochloride; and boron trifluoride diethyl etherate. Of these, azo compounds are preferred.

In the present invention, it is preferable to carry out a polymerization reaction while stirring an organic solvent solution containing the above-mentioned monomer component and polymerization initiator under an inert gas atmosphere or under vacuum. It is preferable that oxygen is substantially completely removed from the solution containing each component and the inside of the reaction vessel. It is desirable to use the polymerization initiator after purification, instead of using a commercial product as it is. The purification method is not particularly limited, and examples thereof include a recrystallization method. For example, when an azo compound such as azobisisobutyronitrile is recrystallized, a high purity of 99% or more can be obtained.

When a purified polymerization initiator is used in an inert gas atmosphere, the molecular weight of the obtained polymer does not become too large and the dispersion can be made small. It is easy to prepare a solution, and the resist characteristics such as sensitivity and resolution are improved.

Acid generator The acid generator is not particularly limited. For example, ultraviolet rays generally used in the field of resists, radiation such as far ultraviolet rays by KrF excimer laser or ArF excimer laser, vacuum ultraviolet rays, electron beams, X-rays, laser beams, etc. And a photoacid generator that generates a Bronsted acid or a Lewis acid upon irradiation with, for example, onium salts, halogenated organic compounds, quinonediazide compounds, α, α′-bis (sulfonyl) diazomethane compounds, α-carbonyl- α′-Sulfonyldiazomethane compounds, sulfone compounds, organic acid ester compounds, organic acid amide compounds, organic acid imide compounds and the like can be used.

Examples of the onium salt include diazonium salts, ammonium salts, iodonium salts such as diphenyliodonium triflate, sulfonium salts such as triphenylsulfonium triflate, phosphonium salts, arsonium salts and oxonium salts.

The halogenated organic compounds include halogen-containing oxadiazole compounds, halogen-containing triazine compounds, halogen-containing acetophenone compounds, halogen-containing benzophenone compounds, halogen-containing sulfoxide compounds, halogen-containing sulfone compounds,
Halogen-containing thiazole compounds, halogen-containing oxazole-based compounds, halogen-containing triazole compounds, halogen-containing 2-pyrone-based compounds, other halogen-containing heterocyclic compounds, halogen-containing aliphatic hydrocarbon compounds,
Examples thereof include a halogen-containing aromatic hydrocarbon compound and a sulfenyl halide compound. More specifically, tris (2,3-dibromopropyl) phosphate, tris (2,3-dibromo-3-chloropropyl) phosphate, tetrabromochlorobutane, hexachlorobenzene, hexabromobenzene, hexabromocyclo Dodecane, hexabromocyclododecene, hexabromobiphenyl, allyltribromophenyl ether, tetrachlorobisphenol A, tetrabromobisphenol A,
Bis (chloroethyl) of tetrachlorobisphenol A
Ether, bis (bromoethyl) ether of tetrabromobisphenol A, bis (2,3
-Dichloropropyl) ether, bis (2,3-dibromopropyl) ether of bisphenol A, bis (2,3-dichloropropyl) ether of tetrachlorobisphenol A, bis (2,3-dibromopropyl) of tetrabromobisphenol A Ether, tetrachlorobisphenol S, tetrabromobisphenol S, bis (chloroethyl) ether of tetrachlorobisphenol S, bis (bromoethyl) ether of tetrabromobisphenol S, bis (2,3-
Dichloropropyl) ether, bis (2,3-dibromopropyl) ether of bisphenol S, tris (2
3-dibromopropyl) isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4- (2-hydroxyethoxy)
-3,5-dibromophenyl) propane and the like, dichlorodiphenyltrichloroethane, pentachlorophenol, 2,4,6-trichlorophenyl 4-nitrophenyl ether, 2,4-dichlorophenyl 3'-methoxy-4 '-Nitrophenyl ether, 2,4-dichlorophenoxyacetic acid, 4,5,6,7
-Tetrachlorophthalide, 1,1-bis (4-chlorophenyl) ethanol, 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethanol, 2,4,
4 ', 5-tetrachlorodiphenyl sulfide, 2,
Organic chloro-based pesticides such as 4,4 ', 5-tetrachlorodiphenyl sulfone are exemplified.

Specific examples of the quinonediazide compound include:
1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,1-naphthoquinonediazide-4-sulfonic acid Ester, 2,1-benzoquinonediazide-5
Sulfonic acid esters of quinonediazide derivatives such as sulfonic acid esters, 1,2-benzoquinone-2-diazide-4-sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride, 1,2-
Naphthoquinone-2-diazide-5-sulfonic acid chloride, 1,2-naphthoquinone-1-diazide-6-sulfonic acid chloride, 1,2benzoquinone-1-diazide-
And sulfonic acid chlorides of quinonediazide derivatives such as 5-sulfonic acid chloride.

The α, α′-bis (sulfonyl) diazomethane compound includes an unsubstituted, symmetrically or asymmetrically substituted alkyl, alkenyl, aralkyl, aromatic or heterocyclic group. Α, α'-
Bis (sulfonyl) diazomethane and the like can be mentioned. α
Specific examples of the -carbonyl-α-sulfonyldiazomethane-based compound include an unsubstituted, symmetrically or asymmetrically substituted alkyl, alkenyl, aralkyl, aromatic, or heterocyclic group-containing α- Carbonyl-
α-sulfonyldiazomethane and the like. Specific examples of the sulfone compound include a sulfone compound and a disulfone compound having an unsubstituted, symmetrically or asymmetrically substituted alkyl group, alkenyl group, aralkyl group, aromatic group, or heterocyclic group. . Examples of the organic acid ester include a carboxylic acid ester, a sulfonic acid ester, and a phosphoric acid ester.Examples of the organic acid amide include a carboxylic acid amide, a sulfonic acid amide, and a phosphoric acid amide. Examples thereof include carboxylic imide, sulfonic imide, and phosphoric imide.

The photoacid generator as described above is also used for a resist for a KrF excimer laser. Among these, around the wavelength of the ArF excimer laser (18)
(5.5-220 nm), for example,
Compounds represented by formula (II) or (III) in column 9-10 of JP-A-7-199467 and specific examples thereof, that is, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate , Dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, 2-oxocyclohexyl (2-norbornyl) sulfonium trifluoromethanesulfonate, 2-cyclohexylsulfonylcyclohexanone, dimethyl (2
-Oxocyclohexyl) sulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, phenylparatoluenesulfonate, the following formula (17)-(26) And the like.

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These photoacid generators may be used alone,
Alternatively, two or more types can be used in combination. The mixing ratio of the photoacid generator is generally 0.01 to 50 parts by weight, preferably 0.2 to 100 parts by weight of the polymer.
It is -30 parts by weight, particularly preferably 0.5-5 parts by weight. When in this range, a good pattern is obtained, which is preferable. Of these photoacid generators, compounds containing a benzene ring tend to increase the absorption of ArF excimer laser light when used in large amounts, so when used alone or in combination with other photoacid generators The mixing ratio is preferably 0.5-5 parts by weight with respect to 100 parts by weight of the polymer.

Other Additives In addition to the above-mentioned polymer and acid generator, other additives may be added to the resist composition of the present invention, if necessary, for example, amines. When amines are used in combination, resist characteristics such as resolution, pattern shape, and mask linearity can be improved even when active light having a short wavelength such as an ArF excimer laser is used as an exposure source. Considering that there is a step of baking the resist film at a high temperature, the amines are preferably high boiling compounds. The amines have a molecular weight of 1
00-240, preferably 120-220, more preferably 140-200 and a boiling point at 760 mmHg of 20
It is desirably 0-350 ° C, preferably 210-330 ° C. If the molecular weight is too large, the melting point generally tends to be high, and amines may be precipitated during storage or development with an alkaline developer. Conversely, if it is too small, the boiling point will be low. On the other hand, if the boiling point is too high, the molecular weight is usually large, the shape is bulky, and the diffusion in the film becomes insufficient, and there is a problem that the shape is reduced due to the effect of the hardly soluble layer on the resist film surface. On the other hand, if the boiling point is too low, it will volatilize at the bake temperature during pattern formation, and a sufficient effect cannot be obtained.

Examples of the amines include aliphatic primary amines such as nonylamine, decylamine, tridecylamine, tetradecylamine and pentadecylamine; aliphatic secondary amines such as diamylamine; tributylamine; Aliphatic tertiary amines such as triamylamine; aromatic amines such as di (4-methylbenzyl) amine, diphenylamine, and tribenzylamine; cyclic aliphatic amines such as hexamethylenetetramine; Among them, aromatic amines such as diphenylamine and cyclic aliphatic amines such as hexamethylenetetramine are preferable.

Resist Solvent The resist composition containing the polymer and the acid generator is uniformly dissolved in a solvent and used as a resist solution. As the solvent, those generally used as a solvent for a resist composition can be used. Specific examples thereof include ketones such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; alcohols such as n-propanol, i-propanol, n-butanol, i-butanol, t-butanol and cyclohexanol; ethylene. Ethers such as glycol dimethyl ether, ethylene glycol diethyl ether and dioxane; alcohol ethers such as ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether; propyl formate, butyl formate, propyl acetate and acetic acid Esters such as butyl, methyl propionate, ethyl propionate, methyl butyrate, and ethyl butyrate; methyl 2-oxypropionate, 2 Oxycarboxylic acid esters such as ethyl oxypropionate, methyl 2-methoxypropionate and ethyl 2-methoxypropionate; cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate and butyl cellosolve acetate; propylene Propylene glycols such as glycol, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether; Halogenated hydrocarbons such as ethylene; aromatic hydrocarbons such as toluene and xylene; polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylacetamide and N-methylpyrrolidone; Is done. These solvents can be used alone or in combination of two or more. The solvent is used in an amount sufficient to dissolve each component uniformly. Further, the resist composition may contain a compatible additive such as a striation inhibitor such as a storage stabilizer, a sensitizer, or a surfactant, if necessary.

When a resist film comprising the resist composition is irradiated (exposed) with radiation, the acid generator generates an acid,
Under the action of the acid, the structural units I and I of the polymer
In I, each protecting group is eliminated to form a polar group such as a carboxylic acid. As a result, the solubility of the irradiated part (exposed area) changes, and the part becomes soluble in an alkaline aqueous solution or a polar solvent. Therefore, this resist composition acts as a positive resist. Further, the structural unit III of the polymer
Does not desorb even by the action of the acid and maintains the adhesion to the substrate.

[0091] As the developing solution developing solution generally using an alkaline aqueous solution, and specific examples thereof include sodium hydroxide, potassium hydroxide, sodium silicate, inorganic alkali such as aqueous ammonia solution; ethylamine, such as propylamine Aqueous solutions of primary amines; aqueous solutions of secondary amines such as diethylamine and dipropylamine; aqueous solutions of alcohol amines such as trimethylamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide; Quaternary ammonium hydroxides such as trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide Aqueous solution and the like. If necessary, a water-soluble organic solvent such as methanol, ethanol, propanol, ethylene glycol or the like, preferably isopropanol, or the like, a surfactant, a resin dissolution inhibitor or the like can be added to the above-mentioned alkaline aqueous solution.

Pattern Forming Method To form a pattern using this resist composition,
Apply the resist solution on the substrate by spin coating etc.,
A film having an arbitrary thickness (usually about 0.01 μm to 2 μm in dry film thickness) is formed, and this is applied to ultraviolet light, far ultraviolet light by KrF excimer laser or ArF excimer laser, vacuum ultraviolet light, electron beam, X-ray, laser light. Exposure is performed using such radiation as a light source. After forming the resist film, before exposure, the temperature is in a range where the resist is not deteriorated by heat, usually 80-1.
It is preferred to bake at 90C, preferably 100-170C. If the bake temperature is too low, a hardly soluble layer will be formed on the resist surface after exposure, and if it is too high, the thermosetting or thermal decomposition of the resist film may occur. 180-250 nm that can be exposed through a mask as an exposure light source
Particularly good results can be obtained when using a light source in the short wavelength region, particularly an ArF excimer laser beam. Further, baking after exposure is usually performed, and the baking after exposure is usually at about 70 to 180 ° C. For the development, the above-described developer may be used.

[0093]

EXAMPLES The synthesis of a novel monomer, the synthesis of a polymer, the preparation of a resist composition and the formation of a resist pattern according to the present invention will be described below with reference to examples. The present invention is not limited by the following embodiments.

[Example 1] Synthesis of novel monomer In a 1 L round bottom flask, tetracyclo [4.4.0.1 was added.
^2.5 . 1 ^7.10 ] -3-dodecene 107g (0.668m
ol), formic acid (purity 98-100%), 127 g (2.7)
6 mol). This solution was vigorously stirred with a Teflon bar with a Dimroth with water flowing down. The system was heated to 100 ° C. in an oil bath to reflux the solution. After 4 hours, return to room temperature, 400m of distilled water
L was added and extracted with n-hexane. The extraction was repeated until the aqueous layer no longer became cloudy. Wash the extract with distilled water,
Then, it was washed with a saturated aqueous solution of sodium hydrogen carbonate and again washed with distilled water until it became neutral. Anhydrous sodium sulfate was added to the solution and dehydrated overnight. The next day, a small amount of activated carbon was added to the solution, filtered, and the filtrate was concentrated on a rotary evaporator. 144 g of residue was obtained. 144 g of the residue obtained above and 200 mL of acetone were charged into a 1 L three-necked flask equipped with an equal pressure dropping funnel and a thermometer. After stirring, the mixture was made a homogeneous solution and then cooled in an ice-water bath. While vigorously stirring this solution with a Teflon bar, chromium trioxide 26
360 g of an 8N chromic acid solution obtained by diluting 7 g and 222 ml of concentrated sulfuric acid with distilled water was slowly dropped from the dropping funnel. During the reaction, the solution was kept at 20-30 ° C. End of dripping 3
After an hour, 100 mL of acetone was newly added. Three hours later, the reaction was terminated, and sodium bisulfite was added. The acetone layer was separated, and the aqueous layer was extracted with acetone.
The acetone extract was stirred with potassium carbonate, filtered, and the filtrate was concentrated on a rotary evaporator. Ethyl acetate was added to the residue, and the mixture was washed with a saturated aqueous solution of potassium carbonate. Anhydrous potassium carbonate and anhydrous sodium sulfate were added to the solution and dehydrated overnight. The next day, the filtrate was concentrated on a rotary evaporator. 112 g of residue were obtained. 107 g of the residue was distilled under reduced pressure to obtain 80 g of tetracyclododecanone. 53 g of tetracyclododecanone in a 1 L three-necked flask equipped with a constant-pressure dropping funnel and a thermometer
(0.301 mol) and dry tetrahydrofuran 18
0.2 mL was charged. After stirring to make a homogeneous solution, -2
Cooled to 0 ° C. Thereafter, the temperature was maintained at -20 ° C during the reaction.
While vigorously stirring this solution with a Teflon bar, 301 ml of a methyllithium solution diluted with diethyl ether was used.
Was slowly dropped from the dropping funnel. Thereafter, the solution was stirred with a Teflon bar for 1 hour. Next, 35 mL of methacrylic acid chloride was slowly dropped from the dropping funnel. After dropping, the solution was stirred with a Teflon bar for 1 hour. Thereafter, the temperature was returned to room temperature, and the reaction solution was poured into 1 L of ice water stirred with a stirring blade. The solution was neutralized with sodium hydrogen carbonate, and the resulting organic layer was separated and washed four times with distilled water. The solution was dehydrated with anhydrous sodium sulfate overnight, and then filtered. The residue obtained by removing the solvent using a rotary evaporator was separated and purified on a silica gel column to give 3-methyltetracyclo [4.4.
0.1 ^2.5 . 47 g of ^17.10 ] -3-dodecyl methacrylate were obtained (colorless and transparent liquid, yield: 40%).

IR (NaCl, neat.cm)^-1): 2
960 (ν, CH), 1720 (ν, C = O), 164
0 (v, C = C), 1160 (v, C-O)¹ H-NMR (CDCl_Three, Internal standard substance: tetramethyl
Silane, ppm): 6.03.5.50 (each
1H), 2.49 (s, 1H), 2.09 (s, 1
H), 2.07 (s, 2H), 1.93 (s, 3H),
1.93 (d, J = 12.1 Hz, 1H^e), 1.88
(D, J = 10.9 Hz, 1H^e), 1.82 (d, J
= 7.3 Hz, 1H), 1.63 (dd, J = 13.2)
Hz, J = 4.4Hz, 1H^Four), 1.51 (dd, J
= 13.2 Hz, J = 3.8 Hz, 1H^a), 1.48
(S, 3H), 1.45 (d, J = 7.3 Hz, 1
H), 1.39 (d, J = 6.9 Hz, 2H^e), 1.
12 (d, J = 12.1 Hz, 1H ^a), 1.09 (d
d, J = 6.9 Hz, J = 2.3 Hz, 2H^a), 0.
88 (d, J = 10.9 Hz, 1H^a), A; Akisha
E, equatorial¹³ C-NMR (CDCl_Three, Ppm): 166.8 (C
= O), 137.6 (-C (CH_Three) =), 124.2
(= CH_Two), 87.1 (C-O), 52.4, 50.
8, 44.6, 40.6, 40.2, 39.6 (C
H), 47.1, 35.9, 33.6, 31.6, 3,
0.4 (CH_Two), 25.6 (CH_Three), 18.3 (-
C (CH_Three) =), GC MS m / z 260, 69

Example 2 Synthesis of homopolymer of methacrylate monomer synthesized in Example 1 In a 100 mL pressure-resistant cider bottle, 13.02 g (0.05 mol) of the methacrylate monomer synthesized in Example 1 was added.
l) and 1.23 g of purified 2,2′-azobisisobutyronitrile recrystallized with methanol (0.0075 mol)
1), then 16.7 mL of 1,4-dioxane
Was added, and a Teflon bar was put therein, sealed tightly with a crown plug, and each component was stirred with a Teflon bar to completely dissolve to give a solution. Nitrogen gas was blown into this solution for 10 minutes (bubbling) to completely remove oxygen from the system including the solution. Thereafter, the pressure-resistant cider bottle was immersed in an oil bath at 80 ° C. to start the polymerization reaction. The solution was immersed in an 80 ° C. oil bath for 7 hours with vigorous stirring with a Teflon bar. Thereafter, the temperature was returned to room temperature, the pressure was released, and then the stopper was removed. The obtained reaction mixture was poured into 3 L of stirred methanol, and the mixture was continuously stirred for 1 hour. Then, the stirring was stopped and the mixture was allowed to stand. The polymerization reaction product precipitated in methanol. After the precipitate was filtered under reduced pressure through filter paper, it was dried overnight in a vacuum drier at 40 ° C. The dried polymerization reaction product was dissolved in 60 mL of tetrahydrofuran, and the solution was then added to 3 mL.
L, poured into methanol, treated as before, filtered and dried. In this way, the desired polymer is
0.98 g (yield 84%) was obtained. Polystyrene equivalent weight average molecular weight (Mw) = 15,199, dispersity (Mw /
Mn) = 3.74.

Example 3 Synthesis of Copolymer of Methacrylate Monomer Synthesized in Example 1 and Mevalonic Lactone Methacrylate In a 100 mL pressure-resistant cider bottle, 7.81 g (0.03 mol) of the methacrylate monomer synthesized in Example 1 was added.
l), 5.95 g of mevalonic lactone methacrylate
(0.03 mol), and 1.48 g of purified 2,2'-azobisisobutyronitrile recrystallized with methanol.
(0.009 mol) was added, and then 1,4-dioxane (20 mL) was added. A Teflon bar was added, the tube was sealed with a crown plug, and each component was stirred with a Teflon bar to completely dissolve the solution. Thereafter, a polymerization reaction was carried out in the same manner as in Example 2, and 9.82 g of the target polymer was obtained (yield: 71).
%)Obtained. Weight average molecular weight (Mw) in terms of polystyrene
= 12,990 and the degree of dispersion (Mw / Mn) = 2.74. The copolymerization ratio at this time was 54/46 of the methacrylate monomer / mevalonic lactone methacrylate obtained in Example 1 from the integration ratio of ¹ H-NMR.

Example 4 Synthesis of Copolymer of Methacrylate Monomer Synthesized in Example 1 and Methoxycarbonylmethylethyl Methacrylate In a 100 mL pressure-resistant cider bottle, 7.81 g (0.03 mol) of the methacrylate monomer synthesized in Example 1 was added.
l), 5.59 g (0.03 mol) of methoxycarbonylmethylethyl methacrylate, and purified 2,2′-azobisisobutyronitrile recrystallized with methanol.
48 g (0.009 mol), and then 1,4-
Dioxane (20 mL) was added, a Teflon bar was added, the tube was sealed with a crown plug, and each component was stirred with a Teflon bar to completely dissolve the solution. Hereinafter, 8.82 g (yield 66%) of the target polymer was obtained in the same manner as in Example 2. Weight average molecular weight (Mw) in terms of polystyrene = 16,69
2. The degree of dispersion (Mw / Mn) was 3.02. The copolymerization ratio at this time was methacrylate monomer / methoxycarbonylmethylethyl methacrylate obtained in Example 1 = 49/51 from the integration ratio of ¹ H-NMR.

[Example 5] Permeability of resist film 1.3 g of the homopolymer synthesized in Example 2, 0.0005 g of a silicon-based surfactant, and 8.7 g of cyclohexanone
, And filtered through a tetrafluoroethylene filter (manufactured by Millipore) having a pore size of 0.1 μm to prepare a homopolymer solution. This solution was spin-coated on a 1-inch quartz substrate and baked in an oven at 115 ° C. for 20 minutes to form a thin film having a thickness of 0.5 μm. The wavelength dependence of the transmittance of the obtained film was measured using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation). As a result, the transmittance at 193 nm of this thin film was 85%, which was sufficient for a single-layer resist. It was confirmed that it exhibited the property.

Comparative Example 1 Transmittance of Poly (2-methyl-2-adamantyl methacrylate) Instead of the homopolymer synthesized in Example 2, poly (2-methyl-2-adamantyl methacrylate) was used.
Methyl-2-adamantyl methacrylate) (Mw = 1
5,203, Mw / Mn = 3.50) Except for using 1.3 g, a thin film was formed in the same manner as in Example 5, and the transmittance was measured. The transmittance of this thin film at 193 nm is 75%.
Met.

[Example 6] Etching resistance of the homopolymer synthesized in Example 2 1.3 g of the homopolymer synthesized in Example 2, 0.0005 g of a silicon-based surfactant, and 8.7 g of cyclohexanone
, And filtered through a tetrafluoroethylene filter (manufactured by Millipore) having a pore size of 0.1 μm to prepare a homopolymer solution. This solution was spin-coated on an 8-inch silicon substrate pre-treated with hexamethyldisilazane (90 ° C., 60 seconds), prebaked on a hot plate at 120 ° C. for 60 seconds, and further heated at 120 ° C. for 6 seconds.
Baking was performed on a hot plate for 0 second to form a thin film having a thickness of 0.7 μm. The etching rate of the obtained film with respect to a fluorine-based gas was measured using an IEM etcher manufactured by Tokyo Electron (etching condition: Pow).
er Top / Bottom = 2000 / 1400W,
Pressure 40mT, gas flow rate C ₄ F ₈ 21sccm, O ₂ 1
1 sccm, Ar 510 sccm). The etching rate was 10690 ° / min.

Comparative Example 2 Etching Resistance of Poly (2-methyl-2-adamantyl methacrylate) Instead of the homopolymer synthesized in Example 2, poly (2-methyl-2-adamantyl methacrylate) was used.
Methyl-2-adamantyl methacrylate) (Mw = 1
5,203, Mw / Mn = 3.50) Except for using 1.3 g, a thin film was formed and the etching rate was measured. The etching rate is 10790 ° /
min.

Example 7 Evaluation of Resist of Copolymer Synthesized in Example 3 The following experiment was conducted under a yellow lamp. 100 parts by weight of the copolymer synthesized in Example 3, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate (photoacid generator), 50 ppm of a silicon-based surfactant, and 0.15 parts by weight of diphenylamine were dissolved in cyclohexanone. The solution was filtered through a 1 μm filter made of tetrafluoroethylene (manufactured by Millipore) to prepare a resist solution (solid content: 14%). The obtained resist solution is
Spin-coated on a silicon substrate pretreated with hexamethyldisilazane, pre-baked at 130 ° C for 60 seconds,
A resist film having a thickness of 0.5 μm was formed. An ArF excimer laser exposure apparatus (Nikon Corporation, N
(A = 0.55) and baked at 100 ° C. for 60 seconds. Next, the film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 60 seconds, and then rinsed with ultrapure water. An L & S (line and space) of 0.17 μm could be resolved with an exposure amount of 30 mJ / cm 2.

Comparative Example 3 Evaluation of Resist of Copolymer of 2-Methyl-2-adamantyl Methacrylate and Mevalonic Lactone Methacrylate The following experiment was conducted under a yellow lamp. 2-
Copolymer of methyl-2-adamantyl methacrylate and mevalonic lactone methacrylate (composition ratio 50
/ 50, Mw = 13,100, Mw / Mn = 2.70)
100 parts by weight, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate (photoacid generator), 50 ppm of a silicon-based surfactant, and 0.15 parts by weight of diphenylamine are dissolved in ethyl lactate and made of tetrafluoroethylene having a pore diameter of 0.1 μm. The solution was filtered through a filter (manufactured by Millipore) to prepare a resist solution (solid content: 13%). Thereafter, exposure and development were carried out in the same manner as in Example 7, and 0.20 μm
L & S (line and space) could be resolved.

Example 8 Evaluation of Resist of Copolymer Synthesized in Example 4 The following experiment was performed under a yellow lamp. 100 parts by weight of the copolymer synthesized in Example 4, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate (photoacid generator), 50 ppm of a silicon surfactant, and 0.15 part by weight of diphenylamine are dissolved in propylene glycol monomethyl ether acetate. , Pore size 0.1
The solution was filtered through a μm filter made of tetrafluoroethylene (manufactured by Millipore) to prepare a resist solution (solid content 1).
5%). Thereafter, exposure and development were performed in the same manner as in Example 7,
0.30 μm L & S (line and space) could be resolved.

Comparative Example 4 Evaluation of Resist of Copolymer of 2-Methyl-2-adamantyl Methacrylate and Methoxycarbonylmethylethyl Methacrylate The following experiment was conducted under a yellow lamp. 2-
Copolymer of methyl-2-adamantyl methacrylate and methoxycarbonylmethylethyl methacrylate (composition ratio 50/50, Mw = 16,000, Mw / Mn
= 2.80) 100 parts by weight, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate (photoacid generator), 50 ppm of a silicon-based surfactant, and 0.15 parts by weight of diphenylamine are dissolved in propylene glycol monomethyl ether acetate, and the pore size is determined. The solution was filtered through a 0.1 μm filter made of tetrafluoroethylene (manufactured by Millipore) to prepare a resist solution (solid content: 15%). Thereafter, exposure and development were performed in the same manner as in Example 7, except that 0.50
Only L & S (line and space) of μm could be resolved.

[0107]

According to the present invention, there is provided a resist composition comprising a polymer having a structural unit containing at least two groups having a norbornane skeleton as a group capable of reacting with an acid to leave.
It has good transmittance and enables fine processing by exposure with an ArF excimer laser. Further, an excellent pattern shape can be obtained stably. Further, since it has excellent etching resistance, it is useful for manufacturing high-performance semiconductors.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 502R

Claims (4)

[Claims] 1. A monomer represented by the following formula (1). Embedded image (Wherein, R is a hydrogen atom or an optionally substituted alkyl group having 1-3 carbon atoms; R ′ is 1-6 carbon atoms)
Is an optionally substituted alkyl group; and Z is a plurality of atoms necessary to complete an optionally substituted alicyclic hydrocarbon group having at least two norbornane skeletons together with the described C. Represents) 2. A polymer having a structural unit represented by the following formula (2). Embedded image (Wherein, R is a hydrogen atom or an optionally substituted alkyl group having 1-3 carbon atoms; R ′ is 1-6 carbon atoms)
Is an optionally substituted alkyl group; and Z is a plurality of atoms necessary to complete an optionally substituted alicyclic hydrocarbon group having at least two norbornane skeletons together with the described C. Represents an integer of 2 to 100,000) 3. A resist composition comprising a polymer containing a structural unit having a group capable of reacting with an acid represented by the following formula (3) and leaving, and an acid generator. Embedded image Wherein R ′ is an optionally substituted alkyl group having 1-6 carbon atoms; Z is at least 2
Represents a plurality of atoms necessary for completing an optionally substituted alicyclic hydrocarbon group having a norbornane skeleton) 4. A pattern forming method, comprising a step of applying the resist composition according to claim 3 on a substrate and a step of exposing using a light source having a wavelength of 180 to 250 nm.