JP2000281729A - Polymer containing diol structure, negative resist composition using it and pattern formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a negative photo resist having dry-etching resistance, high resolution, resistance against swelling deformation and adhesiveness to the substrate by selecting a polymer having a repeating unit containing an alicyclic alkyl group having a diol. SOLUTION: This polymer contains a repeating unit of formula I. In the formula, R1 is H or CH3; R2 is a 2-6C alkylene; X is an alicyclic alkyl group having a diol structure, preferably a group of formulas II-V; (n) is 0-3; and R3-7 is R1. Preferably, the polymer has a diol structure of formula VI and has a weight average molecular weight of 1,000-50,000. In the formula, R8, R10 and R12 are each R1; R9 is a 7-18C crosslinking cyclic hydrocarbon group; R11 is a 7-13C hydrocarbon group having OH group; R13 is H or a 1-12C hydrocarbon group; w+x+y+z=1; and 0<w<=1; 0<=x, y, z<1. The negative photo resist has high transparency to ArF light, excellent dry-etching resistance and little pattern peeling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polymer having a diol structure, a negative resist composition using the same, and a pattern forming method. More specifically, a polymer suitable as a material for a resist used in photolithography using exposure light of 220 nm or less deep ultraviolet light, particularly ArF excimer laser light in the manufacturing process of various semiconductor devices, and a negative resist composition using the same And a pattern forming method.

[0002]

2. Description of the Related Art Various types of semiconductor devices, such as semiconductor devices, which require fine processing on the order of half microns are required to have higher densities and higher integration.
Therefore, the demand for photolithography technology for forming fine circuit patterns has become more and more severe.

As one of means for miniaturizing a pattern, there is a method of shortening the wavelength of exposure light used for forming a pattern using a photoresist. Therefore, in a mass production process of a 256 Mbit DRAM (having a processing dimension of 0.25 μm or less), the conventional i-line (wavelength = 365) is used as an exposure light source.
nm), the use of a shorter wavelength KrF excimer laser (wavelength = 248 nm) is being studied. Also,
In order to manufacture a DRAM having a degree of integration of 1 Gbit or more (processing size of 0.18 μm or less) requiring a finer processing technology, a light source having a shorter wavelength is required. At present, an ArF excimer laser ( 193 nm) is being considered. In lithography using an excimer laser, it is necessary to improve the cost performance of the laser because the life of the gas, which is the material for laser oscillation, is short and the laser device itself is expensive. . For this reason, in addition to high resolution corresponding to miniaturization of processing dimensions, demands for high sensitivity are increasing.

As a highly sensitive photoresist, a chemically amplified resist utilizing a photoacid generator as a photosensitive agent is well known. A characteristic of the chemically amplified resist is that a protonic acid generated from a photoacid generator, which is a component contained by light irradiation, causes an acid-catalyzed reaction with a base resin of the resist by heat treatment after exposure. In this way, the photoreaction efficiency (reaction per photon) is significantly higher than that of a conventional resist having less than 1. Representative examples of chemically amplified resists include triphenylsulfonium hexafluoroacetate and poly (p-tert-butoxycarbonyloxy-α) described in JP-A-2-27660 as positive resists. -Methylstyrene).
Further, as a negative resist, SPIE proceeding of SPIE (1086) is used.
Vol., Pp. 34-47 (1989). E. FIG. Bogan
A resist comprising a combination of the polyvinylphenol and a melamine derivative is described.

[0005] Resins having a benzene ring such as novolak and polyvinyl phenol have been used as resists for g-line, i-line, and KrF excimer laser. However, resins having a benzene ring are not suitable for ArF excimer laser light or the like.
Light absorption is extremely strong for light having a wavelength of 0 nm or less. Therefore, when these resists are used for ArF excimer laser lithography, most of the exposure light is absorbed on the surface of the thin film, and as a result, the exposure light is not transmitted to the substrate, and a fine resist pattern cannot be formed. Therefore g line, i
Resins that have been used for resists for lines and KrF excimer lasers cannot be applied to photolithography using short-wavelength light of 220 nm or less. But g-line,
In the case of i-line and KrF excimer laser exposure resists, there is also the reality that dry etching resistance, which is indispensable for resists for semiconductor production, is obtained from benzene rings in the resin, and it is not only necessary to use benzene rings. That is, the ArF excimer laser exposure resist is required to have etching resistance without containing a benzene ring and to be transparent to a wavelength of 220 nm or less.

Positive resists having high transparency to ArF excimer laser light (193 nm) and dry etching resistance have been actively studied in recent years. Resins having alicyclic hydrocarbon groups are used as base resins in those resists. A typical example is a copolymer having adamantyl methacrylate units [Takechi et al., Journal of Photopolymer Science.
AND TECHNOLOGY (Journal of Pho
toppolymer Science andTech
No. 5, Vol. 3 (No. 3), pp. 439-446 (1992)] and copolymers having isobornyl methacrylate units [R. D. Allen (RD Allen)
Et al., Journal of Photopolymer Science
AND TECHNOLOGY (Journal of Pho
toppolymer Science and Tec
hnology), 8 (4), 623-636 (1995), and 9 (3), 465-474.
(1996)], a copolymer having a carboxylated tricyclodecylmethyl methacrylate unit [Maeda et al., S
PIE Proceding of (Proceeding of
SPIE), vol. 2724, pp. 377-398 (19
1996)].

[0007] On the other hand, there have been very few studies on negative resists for ArF excimer laser exposure. According to the present inventors, negative resists which have obtained high resolution so far are poly (carboxytetracyclododecyl acrylate-hydroxytricyclodecyl acrylate), tetrakis (methoxymethyl) glycoluril, and triphenylsulfonium trif. Negative type resist with only a combination of rates, SPIE Proceding (Proceeding of SPIE), 3333
Vol., Pp. 417-424 (1998) describes a resolution of 0.18 μm by this resist.

[0008]

However, such a negative type photoresist tends to swell in a developing solution when the crosslinking density is insufficient, resulting in deformation of the pattern, and also in the lack of adhesion, which causes the pattern to be deformed. There was a problem that peeling easily occurred. The present invention has been made to solve such a problem, and is preferably used for lithography using light of 220 nm or less such as ArF excimer laser light as exposure light, and has a dry etching resistance and a high resolution. It is an object of the present invention to provide a highly practical negative photoresist having not only properties but also pattern deformation due to swelling and substrate adhesion (a fine pattern is hard to peel off from the substrate).

[0009]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a polymer containing a predetermined diol structure, a negative resist composition using the same, The inventors have found that the above problem can be solved by a pattern forming method, and have completed the present invention.

That is, the present invention provides the following polymer, composition and forming method. [1] A polymer containing a diol structure having a repeating unit represented by the following formula (1).

Embedded image [In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 6 carbon atoms, and X represents an alicyclic alkyl group having a diol structure. ]

[2] X in the formula (1) is an alicyclic alkyl group having a diol structure represented by the following formula (2), (3), (4) or (5): 1] The polymer according to the above.

Embedded image [In the formula (2), n represents an integer of 0 to 3, and R ³ and R ⁴ each represent a hydrogen atom or a methyl group. ]

[0012]

Embedded image [In the formula (3), R ⁵ represents a hydrogen atom or a methyl group. ]

[0013]

Embedded image [In the formula (4), R ⁶ represents a hydrogen atom or a methyl group. ]

[0014]

Embedded image [In the formula (5), R ⁷ represents a hydrogen atom or a methyl group. ]

[3] It has a diol structure represented by the following formula (6) and has a weight average molecular weight of 1,000 to 50,000.
The polymer according to [1] or [2], which is 00.

[0016]

Embedded image [In the formula (6), R ¹ and R ² are the same as in the formula (1), X is the same as in the formulas (1) to (5), and R ⁸ is a hydrogen atom or methyl. R ⁹ is a bridged cyclic hydrocarbon group having 7 to 18 carbon atoms having a carboxyl group, R ¹⁰ is a hydrogen atom or a methyl group, R ¹¹ is a hydrocarbon group having 7 to 13 carbon atoms having a hydroxyl group, R ¹² Is a hydrogen atom or a methyl group, R ¹³ is a hydrogen atom or a carbon number of 1 to 1.
2 hydrocarbon groups. In addition, w, x, y, and z are respectively w + x + y + z = 1, 0 <w ≦ 1, 0 ≦ x <1, and 0 ≦ y
<1, 0 ≦ z <1 is an arbitrary number satisfying. ]

[4] A polymer comprising the diol structure according to any one of [1] to [3], and a polymer represented by the following formula (7):
A negative photoresist composition comprising a cross-linking agent comprising a compound having a functional group shown in (1) and a photoacid generator which generates an acid upon exposure.

[0018]

Embedded image [In the formula (7), R ¹⁴ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an oxoalkyl group having 3 to 6 carbon atoms. ]

[5] The negative photoresist composition according to [4], further comprising a polyhydric alcohol compound.

[6] The crosslinking agent is represented by the following formulas (8) to (1).
The negative photoresist composition according to [4] or [5], which is at least one of the compounds described in 2).

[0021]

Embedded image[In the formula (8), R¹⁴Is the same as in equation (7)
Yes, a₁Is 1 or 2, a₂Is 1 or 2, b₁Is 0 or
1, b₂Represents 0 or 1, respectively, and a₁+ B ₁= 2,
a₂+ B₂= 2. ]

[0022]

Embedded image [In the formula (9), R ¹⁴ is the same as in the formula (7), and R ¹⁵ represents a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or an oxoalkyloxy group having 3 to 6 carbon atoms. . ]

[0023]

Embedded image [In the formula (10), R ¹⁴ is the same as in the formula (7), and R ¹⁶ is a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an oxoalkyloxy group having 3 to 6 carbon atoms, R ¹⁷ represents an oxygen atom, a sulfur atom, an alkylene group having 1 to 3 carbon atoms, or a hydroxymethylene group. ]

[0024]

Embedded image [In the formula (11), R ¹⁴ is the same as in the formula (7), and R ¹⁸ represents a hydrogen atom or a methyl group. ]

[0025]

Embedded image [7] The photoacid generator is a sulfonium salt compound represented by the following formula (13), an iodonium salt compound represented by the following formula (15), an imide compound represented by the following formula (16), or a formula represented by the following formula (17) The negative photoresist composition according to any one of [4] to [6], which is at least one diazo compound.

[0026]

Embedded image [In the formula (13), R ¹⁹ , R ²⁰ , and R ²¹ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo aliphatic compound. cyclic alkyl group, an alkyl group, Y ^- is BF ₄ ^-,
And AsF ₆ ⁻ , SbF _6, or a counter ion represented by the following formula (14). ]

[0027]

Embedded image [In the formula (14), Z represents C _n F _{2n + 1} (n is an integer of 1 to 6), an alkyl group, an alkyl-substituted, halogen-substituted or unsubstituted aromatic group. ]

[0028]

Embedded image [In formula (15), R ²² and R ²³ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo alicyclic alkyl. group, an alkyl group, Y ^- is the same as that of formula (13). ]

[0029]

Embedded image [In the formula (16), R ²⁴ is a halogen-substituted or unsubstituted alkylene group, an alkyl-substituted, halogen-substituted or unsubstituted divalent aromatic group, R ²⁵ is a halogen-substituted or unsubstituted alkyl group, an alkyl group, It represents a halogen-substituted or unsubstituted aromatic group. ]

[0030]

Embedded image [In the formula (17), R ²⁶ and R ²⁷ each independently represent a halogen-substituted or unsubstituted alkyl group, a halogen-substituted or unsubstituted aromatic group, or an alicyclic hydrocarbon group. ]

[8] 50 to 98 parts by weight of the polymer,
It contains 1 to 50 parts by weight of the crosslinking agent and 0.2 to 15 parts by weight of a photoacid generator which generates an acid upon exposure [4] to
The negative photoresist composition according to any one of [7].

[9] A step of applying the negative photoresist composition according to any one of [4] to [8] on a substrate to be processed, and the step of applying the negative photoresist composition with light having a wavelength of 180 to 220 nm. A resist pattern forming method including a step of exposing an object, a step of performing baking, and a step of performing development.

[10] The method for forming a resist pattern according to [9], wherein the light having a wavelength of 180 nm to 220 nm is ArF excimer laser light.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. 1. Polymer Containing Diol Structure The polymer of the present invention is a polymer containing a diol structure having a repeating unit represented by the above formula (1). In the formula (1), X represents an alicyclic alkyl group having a diol structure. Examples of the alicyclic alkyl group having a diol structure include the alicyclic alkyl groups represented by the formulas (2), (3), (4), and (5).

More specifically, the 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ] decyl group shown in Table 1
Dihydroxy-dimethyltricyclo [5.2.1.0 ^2,6 ] decyl group, 3,4-dihydroxytetracyclo [4.4.0.
1 ^2,5 .1 ^7,10] dodecyl methyl group, 3,4-dihydroxy-8-methyl-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecyl methyl or dihydroxy adamantyl group, dihydroxy isobornyl group , A dihydroxyadamantyl group, a dihydroxyisobornyl group and the like.

[0036]

[Table 1]

Specific examples of the polymer of the present invention include a polymer having a diol structure represented by the above formula (6) and having a weight average molecular weight of 1,000 to 50,000.

In the formula (6), R ⁹ is specifically a carboxytricyclo [5.2.1.0 ^2,6 ] decylmethyl group, a carboxytricyclo [5.2.1.0 ^2,6 ] decyl group as shown in Table 2,
Carboxy adamantyl group, carboxy norbornyl group, a carboxymethyl norbornyl group, carboxy isobornyl group, carboxy tetracyclo [4.4.0.1 ^2,5 .1 ^7,
10 ] dodecyl group, carboxymethyltetracyclo [4.4.
0.1 ^2,5 .1 ^7,10 ] dodecyl group, and the like, but is not limited thereto.

For patterning, an unexposed negative photoresist must be dissolved in a developer, and an alicyclic group having a carboxyl group has an effect of increasing the dissolution rate of the negative photoresist in the developer. Further, the crosslinked cyclic hydrocarbon has an effect of improving dry etching resistance.

[0040]

[Table 2]

R ¹¹ is specifically a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxycyclohexyl group, a hydroxydimethylcyclohexyl group, a hydroxytricyclo [5.2.1.0 ^2,6 ] decyl group, a hydroxyadamantyl group , hydroxy norbornyl group, hydroxy isobornyl group, hydroxy tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecyl group, and the like are not limited only to these.

R ¹³ is specifically a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
Isobutyl, t- butyl group, a cyclohexyl group, dimethyl cyclohexyl group, a tricyclo [5.2.1.0 ^{2, 6]} decyl group, an adamantyl group, norbornyl group, isobornyl group, tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] Examples thereof include a dodecyl group, but are not limited thereto.

The polymer of the present invention is, for example, disclosed in Japanese Patent Application No. 10-3.
It can be obtained by polymerizing a monomer such as an alicyclic (meth) acrylate derivative having a diol structure described in 12171 using a suitable radical polymerization initiator. Specifically, a radical polymerization initiator such as azobisisobutyronitrile or benzoyl peroxide is added in a solvent such as tetrahydrofuran under an inert gas (argon, nitrogen, etc.) atmosphere, and the solution is added at 0. It can be obtained by heating and stirring for 5 to 12 hours.

The alicyclic (meth) acrylate derivative having a diol structure can be synthesized, for example, according to the following. The alicyclic (meth) acrylate having an unsaturated bond represented by the following formula (18) is epoxidized with a peroxide such as m-chloroperbenzoic acid to obtain the following formula (19)
Alicyclic epoxy (meth) acrylate shown in
Further, it can be obtained by performing a ring opening reaction of an epoxy group with perchloric acid or the like. The alicyclic (meth) acrylate represented by the formula (19) used herein is represented by the following formula (20)
Can be obtained by reacting an alicyclic alcohol shown in (1) with (meth) acrylic acid chloride using an alkali catalyst such as a tertiary amine. Further, it can also be synthesized by reacting the alicyclic alcohol represented by the formula (20) with (meth) acrylic acid using an acid catalyst such as trifluoroacetic acid.

Embedded image [In the formula (18), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene chain having 2 to 6 carbon atoms, and n represents an integer of 0 to 3. ]

[0045]

Embedded image [In the formula (19), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene chain having 2 to 6 carbon atoms, and n represents an integer of 0 to 3. ]

[0046]

Embedded image [In the formula (20), n represents an integer of 0 to 3. The polymer represented by the formula (6) can be obtained by polymerizing a monomer using a suitable radical polymerization initiator. Specifically, a radical polymerization initiator such as azobisisobutyronitrile or benzoyl peroxide is added in a solvent such as tetrahydrofuran under an inert gas (argon, nitrogen, etc.) atmosphere at a temperature of 0.5 to 50.degree. It can be obtained by heating and stirring for up to 12 hours. As for the copolymerization ratio, a polymer having an arbitrary copolymerization ratio can be obtained by selecting polymerization conditions such as the ratio of charged monomers. The weight average molecular weight of this polymer is preferably from 1,000 to 500,000, more preferably from 3,000 to 200,000.
0. If the molecular weight is less than 1,000, the polymer has a low glass transition point and may be difficult to handle as a resist. If it exceeds 500,000, it may be difficult to form a uniform film on a substrate.

2. Negative photoresist composition The negative photoresist composition of the present invention contains the polymer, a crosslinking agent, a photoacid generator and, if necessary, a polyhydric alcohol compound. Here, as the crosslinking agent, a compound containing a group represented by the above formula (7) can be exemplified.
The compound having a functional group represented by the formula (7) has a property of reacting with a hydroxyl group in the presence of an acid catalyst as shown in the following reaction formula (A). That is, the polymer having a hydroxyl group is crosslinked by a compound having a functional group represented by the formula (7) in the presence of an acid catalyst. If the polymer is soluble in the developer, the polymer becomes insoluble in the developer due to the crosslinking.

The negative photoresist of the present invention comprises a polymer having an alicyclic alkyl group having a diol structure having two hydroxyl groups in a repeating unit. That is, the polymer in the negative photoresist of the present invention is:
It has more reaction sites with a crosslinking agent than a conventionally known polymer having a monol.

Further, in the polymer in the negative photoresist of the present invention, the hydroxylated alicyclic alkyl group (X in the general formula (1)) has an alkylene chain between the alicyclic alkyl group and the main chain of the polymer. (R ² in the general formula (1)), the degree of freedom in the resist film is relatively large, and as a result, the reactivity to the crosslinking agent increases. That is,
The polymer in the negative photoresist of the present invention has a large number of reaction sites with respect to the crosslinking agent and has high reactivity with the crosslinking agent, so that a high crosslinking density can be obtained.

Thus, when a polymer containing a group having a diol structure is used for a negative resist, pattern deformation due to insufficient crosslinking is unlikely to occur. Further, since the polymer containing a group having a diol structure has two polar groups having an action of improving the adhesion to the substrate, the formed resist pattern is not easily peeled off from the substrate.

[0051]

Embedded image [In the above formula (7), R ¹⁴ is a hydrogen atom, having 1 to 6 carbon atoms.
Or an oxoalkyl group having 3 to 6 carbon atoms. ]

[0052]

Embedded image Examples of the compound containing the group represented by the formula (7) include compounds represented by the following formulas (8) and (12).

[0053]

Embedded image [In the formula (8), R ¹⁴ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms (specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl A hexyl group, etc., but is not limited thereto.) Or 3 carbon atoms.
To 6 oxoalkyl groups (specifically, β-oxopropyl, β-oxobutyl, β-oxoheptyl,
represents a β-oxohexyl group or the like, but is not limited thereto. ). a ₁ is 1 or 2, a ₂ is 1 or 2, b ₁ is 0 or 1, b ₂ is 0 or 1, a ₁ + b ₁ =
2, a ₂ + b ₂ = 2. ]

[0054]

Embedded image [In the general formula (9), R ¹⁴ is the same as in the case of the formula (8), and R ¹⁵ is a hydrogen atom, a hydroxyl group or an alkoxy group having 1 to 6 carbon atoms (specifically, a methoxy group, an ethoxy group, a propoxy group) Group, isopropyloxy group, butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group,
Represents a hexyloxy group or the like, but is not limited thereto. ) Or an oxoalkyloxy group having 3 to 6 carbon atoms (specifically, a β-oxopropoxy group, a β-oxobutoxy group, a β-oxoheptyloxy group, a β-oxohexyloxy group, and the like, but not limited thereto. It is not.) ]

[0055]

Embedded image [In the general formula (10), R ¹⁴ is the same as in the case of the formula (8), and R ¹⁷ is an oxygen atom, a sulfur atom, an alkylene group having 1 to 3 carbon atoms (specifically, a methylene group, an ethylene group, Represents a propylene group, a 1-methylethylene group, etc., but is not limited thereto.) And a hydroxymethylene group. ]

[0056]

Embedded image [In the formula (11), R ¹⁴ is the same as in the case of the formula (8), and R ¹⁸ represents a hydrogen atom or a methyl group or an ethyl group. ]

In the compound containing a group represented by the formula (7) which is a crosslinking agent of the negative photoresist composition of the present invention, for example, methylol urea in which R ¹⁴ is a hydrogen atom is obtained by converting urea to methylol with formaldehyde. Can be synthesized.

The compound of the formula (8) wherein R ¹⁴ is an alkyl group or an oxoalkyl group can be obtained by treating methylol urea with the corresponding alcohol. For example, when treated with methanol, dimethylated methylol urea [in Formula (8), R ¹⁴ is a methyl group (alkyl group having 1 carbon atom)], and when treated with ethanol, diethyl methylol urea [in Formula (8), R ¹⁴ is ethyl] Group (alkyl group having 2 carbon atoms)], and when treated with isobutanol, diisobutylated methylol urea [in the formula (8), R ¹⁴ is an isobutyl group (alkyl group having 4 carbon atoms)], 2-oxopropanol (also called hydroxyacetone) To obtain a di-β-oxopropylated methylol urea [in the formula (8), R ¹⁴ is a β-oxopropyl group (an oxoalkyl group having 3 carbon atoms)].

In the compound represented by the formula (9), for example, 1,3-bis (hydroxymethyl) ethylene urea (also called 1,3-bis) in which R ¹⁴ is a hydrogen atom and R ¹⁵ is a hydrogen atom in the formula (9) Dimethylol imidazolidone-
2) can be obtained by reacting urea with ethylenediamine and formaldehyde.

In the equation (9), R¹⁴Is alkyl
Group or oxoalkyl group, R^{1 5}Is a hydrogen atom
The compound is 1,3-bis (hydroxymethyl) ethylene
By treating urea with the corresponding alcohol
Obtainable. For example, when treated with methanol
1,3-bis (methoxymethyl) ethyleneurea [Formula
In (9), R¹⁴Is a methyl group (alkyl having 1 carbon atom)
Group), R^FifteenIs a hydrogen atom], when treated with ethanol
1,3-bis (ethoxymethyl) ethyleneurea [Formula
In (9), R¹⁴Is an ethyl group (alkyl having 2 carbon atoms)
Group), R^FifteenIs a hydrogen atom], treated with isobutanol
And 1,3-bis (isobutoxymethyl) ethyleneurea
[In the formula (9), R¹⁴Is an isobutyl group (with 4 carbon atoms)
Alkyl group), R ^FifteenIs a hydrogen atom], 2-oxopropa
1,3 when treated with knol (also known as hydroxyacetone)
-Bis (β-oxopropoxymethyl) ethylene urea
[In the formula (9), R¹⁴Is a 2-oxopropyl group (charcoal
An oxoalkyl group having a prime number of 3), R^{1 5}Is a hydrogen atom]
Can be

Also, in the formula (9), 1,3-bis (hydroxymethyl) -4,5-bis (hydroxy) ethylene urea wherein R ¹⁴ is a hydrogen atom and R ¹⁵ is a hydroxyl group (also known as 1,3-dimethylol- 4,5-Dihydroxyimidazolidone-2) can be synthesized by reacting urea with glyoxal and then converting it to methylol with formaldehyde.

[0062] Further, compounds ^{wherein R 14} is an alkyl group or an oxoalkyl ^{group, R 1 5} is an alkoxy group or an oxo alkoxy group in the formula (9) include 1,3-bis (hydroxymethyl) -4,5-bis (Hydroxy)
It can be obtained by treating ethylene urea with the corresponding alcohol. For example, when treated with methanol, 1,3-bis (methoxymethyl) -4,5-bis (methoxy) ethyleneurea [R ¹⁴ in the formula (9)]
There methyl group (alkyl group having 1 carbon ^{atom), R 15} is a methoxy group (an alkoxy group having 1 carbon atom), also by treatment with ethanol and 1,3-bis (ethoxymethyl) -4,5
Bis (ethoxy) ethyleneurea [R in formula (9)
¹⁴ is an ethyl group (an alkyl group having 2 carbon atoms), R ¹⁵ is an ethoxy group (an alkoxy group having 2 carbon atoms)], and when treated with isopropanol, 1,3-bis (isopropoxymethyl) -4,5-bis (iso- Propoxy) ethylene urea [In the formula (9), R ¹⁴ is an isopropyl group (having 3 carbon atoms)
Alkyl group) ^{of, R 15} is propyl group (3 carbon atoms
Alkoxy group)] and treated with tert-butanol to give 1,3-bis (tert-butoxymethyl) -4,5
-Bis (tert-butoxy) ethylene urea [In the formula (9), R ¹⁴ represents a tert-butyl group (C 4
Alkyl ^group), alkoxy groups ^{R 15} is tertiary butoxy group (4 carbon atoms)], treatment with 2-oxo-propanol (also known as hydroxyacetone) 1,3-bis (beta
-Oxopropoxymethyl) -4,5-bis (β-oxopropoxy) ethyleneurea [In the formula (9), R
¹⁴ is a β-oxopropyropyl group (an oxoalkyl group having 3 carbon atoms), and R ¹⁵ is a β-oxopropoxy group (an oxoalkoxy group having 3 carbon atoms).

In the compound represented by the formula (10), for example, in the formula (10), R ¹⁴ and R ¹⁶ are hydrogen atoms, R ¹⁷
Is a methylene group, 1,3-bis (hydroxymethyl)
In the case of -tetrahydro-2 (1H) pyrimidinone, it can be obtained by reacting urea with propylenediamine and further reacting with formaldehyde.

In the formula (10), when R ¹⁴ is an alkyl group, R ¹⁶ is a hydrogen atom and R ¹⁷ is a methylene group, 1,3-bis (hydroxymethyl) -tetra-hydro-2 (1H) pyrimidinone is used. It can be obtained by treating with the corresponding alcohol. For example, when treated with methanol, dimethylated 1,3-bis (hydroxymethyl) -tetrahydro-2 (1H) pyrimidinone [in the formula (10), R ¹⁴ is a methyl group (an alkyl group having 2 carbon atoms), R ¹⁶ is a hydrogen atom, R ¹⁷ is a methylene group (alkylene group having 1 carbon atom)], and treated with ethanol to give diethylated 1,3-bis (hydroxymethyl) -tetrahydro-2 (1H) pyrimidinone [In the formula (10), R ¹⁴ is an ethyl group (carbon An alkyl group of Formula 2), R
¹⁶ is a hydrogen atom, R ¹⁷ is a hydrogen atom of a methylene group (alkylene group having 1 carbon atom)], and treated with isobutanol, butylated 1,3-bis (hydroxymethyl) -tetrahydro-2 (1H) pyrimidinone [formula (10) At R
¹⁴ isobutyl group (an alkyl group having 4 carbon ^{atoms), R 16}
Is a hydrogen atom, and R ¹⁷ is a methylene group (alkylene group having 1 carbon atom)].

In the formula (10), R ¹⁴ and R ¹⁶
Is a hydrogen atom, and R ¹⁷ is an oxygen atom. The dimethylol uron can be obtained by reacting urea with formaldehyde in a molar ratio of 4 times that of urea.

Further, R ¹⁴ and R ¹⁶ are a hydrogen atom, R ¹⁷
Is a hydroxymethylene group, 1,3-bis (hydroxymethyl) -tetrahydro-5-hydroxy-2 (H)
Pyrimidinone can be obtained by reacting urea with 2-hydroxypropylenediamine and further reacting with formaldehyde.

In the case of the compound represented by the formula (11),
In general, for example, in general formula (11), R ¹⁴Is a hydrogen atom,
R¹⁸Is a hydrogen atom, 1,3,4,6-tetrakis
(Hydroxymethyl) glycoluril (also known as 1,3
4,6-tetrakis (hydroxymethyl) acetylene
Rear, tetramethylolated greoxazole diurei
G), glyoxazole and twice the molar amount of urea are
And then methylolate with formaldehyde
Can be synthesized.

In the equation (11), R¹⁴Is archi
Or an oxoalkyl group, R ¹⁸Is a hydrogen atom
In the case of the compound, 1,3,4,6-tetrakis (hydroxy
Methyl) glycoluril with the corresponding alcohol
It can be obtained by processing. For example, methano
And 1,3,4,6-tetrakis (Metoki)
(Cimethyl) glycoluril [in the formula (11), R
¹⁴Is a methyl group (alkyl group having 1 carbon atom), R¹⁸But water
Elementary atom], when treated with ethanol, 1,3,4,6-te
Thrakis (ethoxymethyl) glycoluril [Formula (1)
In 1), R^{1 4}Is an ethyl group (alkyl having 2 carbon atoms)
Group), R¹⁸Is a hydrogen atom], treated with isobutanol
And 1,3,4,6-tetrakis (isobutoxymethyl)
Glycoluril [in the formula (11), R¹⁴Is isobu
Tyl group (alkyl group having 4 carbon atoms), R ¹⁸Is a hydrogen source
Child], 2-oxopropanol (also known as hydroxyaceto
1,3,4,6-tetrakis (β-O
Xopropoxymethyl) glycoluril [formula (10)
At R¹⁴Is a β-oxopropyl group (C 3
Oxoalkyl group), R¹⁸Is a hydrogen atom]
Wear.

The photoacid generator used in the present invention includes
It is preferably a photoacid generator that generates an acid upon irradiation with light having a wavelength of 180 nm to 220 nm, and the mixture with the polymer of the resist composition of the present invention described above is sufficiently dissolved in an organic solvent, and It is preferable that the solution can form a uniform coating film by a film forming method such as spin coating. Also, 1
Species may be used alone or in combination of two or more.

Examples of the photoacid generator that can be used include a sulfonium salt compound represented by the above formula (13) and a compound represented by the following general formula (1):
An iodonium salt compound represented by 5), a succinimide derivative represented by the general formula (16), a diazo compound represented by the formula (17), 2,6-dinitrobenzyl esters, a disulfone compound, and the like can be used. Examples of these include the Journal of the Organic Chemistry (Jo
urnal of the Organic Chem
Istry), Vol. 43, No. 15, pp. 3055-3058
Page (1978). V. JV Crivello et al., A triphenylsulfonium salt derivative, Journal of the Polymer Science (Journal of the Polymer).
r Science), 56, 383-395 (1976). V. A diphenyliodonium salt derivative of JV Crivello et al., Cyclohexylmethyl (2-oxocyclohexyl) disclosed in JP-A-7-28237.
Alkylsulfonium salt derivatives such as sulfonium trifluoromethanesulfonate; β-oxocyclohexylmethyl (2) disclosed in JP-A-8-27102;
-Norbornyl) sulfonium There are sulfonium salt compounds having a bridged cyclic alkyl group such as trifluoromethanesulfonate. In addition, 2,6-dinitrobenzyl esters [O. O. Nalam
asu) et al., SPIE Proceeding, Vol. 1262,
32 (1990)], 1,2,3-tri (methanesulfonyloxy) benzene [Takumi Ueno et al., Proceeding of PME '89, Kodansha, 413-4]
24 (1990)], disulfone compounds and the like.

[0071]

Embedded image [In the formula (13), R ¹⁹ , R ²⁰ , and R ²¹ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo aliphatic compound. cyclic alkyl group, an alkyl group, Y ^- is BF ₄ ^-,
And AsF ₆ ⁻ , SbF _6, or a counter ion represented by the following formula (14). ]

[0072]

Embedded image [In the formula (14), Z represents C _n F _{2n + 1} (n is an integer of 1 to 6), an alkyl group, an alkyl-substituted, halogen-substituted or unsubstituted aromatic group. ]

[0073]

Embedded image [In formula (15), R ²² and R ²³ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo alicyclic alkyl. group, an alkyl group, Y ^- is the same as that of formula (13). ]

[0074]

Embedded image [In the formula (16), R ²⁴ is a halogen-substituted or unsubstituted alkylene group, an alkyl-substituted, halogen-substituted or unsubstituted divalent aromatic group, R ²⁵ is a halogen-substituted or unsubstituted alkyl group, an alkyl group, It represents a halogen-substituted or unsubstituted aromatic group. ]

[0075]

Embedded image [In the formula (17), R ²⁶ and R ²⁷ each independently represent a halogen-substituted or unsubstituted alkyl group, a halogen-substituted or unsubstituted aromatic group, or an alicyclic hydrocarbon group. ]

When the negative photoresist composition of the present invention contains a polyhydric alcohol (dihydric or higher alcohol), the resolution may be improved. This is because a polyhydric alcohol having high reactivity with the crosslinking agent acts as a crosslinking accelerator. As the polyhydric alcohol used as needed in the present invention, for example, ethylene glycol,
Glycerol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2,4-butanetriol, 1,2-pentanediol, 1,4- Pentanediol, 1,5-
Pentanediol, 2,4-pentanediol, 1,2
-Hexanediol, 1,5-hexanediol, 1,
6-hexanediol, 2,5-hexanediol,
1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,
2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3,5-cyclohexanetrimethanol, 1,2-cyclopentanediol, 1,3-
Cyclopentanediol, 1,2-cyclooctanediol, 1,5-cyclooctanediol, tricyclodecanedimethanol, 2,3-norbornanediol, 2
(3) -hydroxy-5,6-bis (hydroxymethyl) norbornane, 2,3-dihydroxy-5 (6)-
Hydroxymethylnorbornane, 1,4-anhydroerythritol, L-arabinose, L-arabitol,
Examples include, but are not limited to, D-cellobiose, cellulose, 1,5-decalindiol, glucose, galactose, lactose, maltose, mannose, mannitol, and the like.

The content of the polymer having a diol structure in the negative photoresist composition of the present invention is usually 50 to 98 parts by weight, preferably 70 to 95 parts by weight, per 100 parts by weight of all the components including itself. Parts by weight. If the content is less than 50 parts by weight, it is difficult to form a uniform film. On the other hand, if the amount exceeds 98 parts by weight, the amount of the crosslinking agent and the photoacid generator that can be introduced is inevitably reduced.

The content of the crosslinking agent is usually 1 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of all the components including itself. If the content is less than 1 part by weight, crosslinking of the polymer does not sufficiently occur and a pattern cannot be obtained. Also, if it exceeds 50 parts by weight,
It is difficult to form a uniform film, and the transparency of the thin film may decrease. Furthermore, the content of the polymer is also insufficient,
In some cases, sufficient etching resistance cannot be obtained.

The content of the photoacid generator is usually 0.2 to 15 parts by weight based on 100 parts by weight of all the components including itself.
Parts by weight, preferably 0.5 to 10 parts by weight. If the content is less than 0.2 parts by weight, the sensitivity of the negative resist composition of the present invention is remarkably reduced, and it is difficult to form a pattern. On the other hand, when the amount exceeds 15 parts by weight, it becomes difficult to form a uniform coating film, and there is a problem that a residue (scum) is easily generated after development.

When a polyhydric alcohol is contained,
The content of 0.2 to 20 parts by weight based on 100 parts by weight of all components including itself has an effect of improving resolution.

Further, a preferable solvent used in the present invention is an organic solvent in which the negative resist composition of the present invention is sufficiently dissolved and the solution is capable of forming a uniform coating film by a method such as spin coating. There is no particular limitation as long as it is a solvent.
Moreover, you may use individually by 1 type or in mixture of 2 or more types.

Specifically, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, ter
t-butyl alcohol, methyl cellosolve acetate,
Ethyl cellosolve acetate, propylene glycol monoethyl ether acetate (1-methoxy-2-acetoxypropane), methyl lactate, ethyl lactate, acetic acid 2-
Methoxybutyl, 2-ethoxyethyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, N-methyl-2-pyrrolidinone, cyclohexanone, cyclopentanone, cyclohexanol, Methyl ethyl ketone, 1,
4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate
, Ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, and the like, but are not limited thereto. Further, other components such as a surfactant, a dye, a stabilizer, a coating improver, and a dye may be added to the resist composition of the present invention as needed.

The negative resist composition of the present invention uses, as a base resin, a polymer having an alicyclic alkyl group, which is known to provide high dry etching resistance.
Further, since this polymer has no benzene ring, it has high transparency to light having a short wavelength of 220 nm or less such as ArF excimer laser light. As described above, the resist composition of the present invention is a chemically amplified resist,
It has both transparency to short wavelength light of 220 nm or less such as excimer laser light and high dry etching resistance. Therefore, it can be used as a new negative photoresist material for manufacturing semiconductor devices.

3. Pattern Forming Method The present invention also provides a method for forming a negative pattern of a photoresist on a substrate to be processed using the above negative photoresist composition. FIG. 1 shows a method of forming a negative pattern according to the present invention.

First, as shown in FIG. 1A, a negative photoresist material of the present invention is applied on a substrate 1 to be processed.
Then, the resist film 2 is formed by performing a pre-baking process at 60 to 170 ° C. for 30 to 240 seconds using a heating means such as a hot plate. Next, as shown in FIG. 1B, the resist film 2 is selectively exposed by an exposure device using a photomask 3. After the exposure, the resist 2 film is subjected to a heat treatment. As a result, as shown in FIG. 1 (C), in the exposed region 4, crosslinking of the resin occurs. And finally Figure 1
As shown in (D), only an unexposed portion of the resist film 2 is selectively dissolved and removed by an alkali developing solution such as an aqueous solution of tetramethylammonium hydroxide (TMAH) to form a negative pattern.

[0086]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention.

(Example 1) Synthesis of polymer A1 having the following structure

[0088]

Embedded image

[0089] In 100ml round-bottomed flask with a reflux pipe, 3,4-dihydroxy tricyclo [5.2.1.0 ^{2, 6]} decyl oxyethyl acrylate 0.52 g, carboxy tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 1} ] 3.31 g of dodecyl acrylate and 5 g of hydroxytricyclodecyl acrylate were dissolved in 36 ml of dry tetrahydrofuran, and azobisisobutyronitrile (AIBN) 119 m was added thereto.
g and stirred at 60-65 ° C. under an argon atmosphere. After cooling for 2 hours, the reaction mixture was poured into 400 ml of hexane / ether (4/1), and the deposited precipitate was separated by filtration. Further re-precipitation purification was performed again to obtain 4.8 g of the desired product (yield: 54.4%). The copolymerization ratio at this time was 5:33:62 from the integration ratio of ¹ H-NMR. The molecular weight of the obtained resin A1 was 8,300. The molecular weight was determined by gel permeation using LC-9A manufactured by Shimadzu Corporation (column: KF-80M manufactured by Showa Denko).
It was measured by chromatography (GPC) and determined as a molecular weight in terms of polystyrene.

Example 2 A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Resin A1 (A1 synthesized in Example 1) 3.7 g (b) Crosslinking agent B1 (B1 shown below) 0.28 g (c) Photoacid generator C1 (triphenylsulfonium trifluoromethanesulfonate) G) (C1 shown below) 0.02 g (d) diethylene glycol dimethyl ether 18.2 g

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The molecular weight of the resin A1 used was 8,300. Here, the molecular weight was measured by gel permeation chromatography (GPC) using LC-9A manufactured by Shimadzu Corporation (column: KF-80M manufactured by Showa Denko KK) and determined as a molecular weight in terms of polystyrene. Add the above mixture to 0.
After filtration through a 2 μm tetron filter, a resist was prepared. This was spin-coated on a 3-inch quartz substrate, and heated on a hot plate at 120 ° C. for 60 seconds to form a thin film having a thickness of 0.4 μm. 193.4 of this thin film
The transmittance in nm light (center wavelength of ArF excimer laser light) was measured by an ultraviolet spectrophotometer (UV365, manufactured by Shimadzu Corporation), and the transmittance was 68%. This is sufficient transparency as a single-layer resist.

(Example 3) The resist prepared in Example 2 was spin-coated on an 8-inch silicon substrate and heated on a hot plate at 120 ° C for 60 seconds to form a film having a thickness of 0.4.
A μm thin film was formed. This was exposed through a mask using a Nikon ArF excimer laser exposure apparatus (NA = 0.55). Immediately thereafter, baked on a hot plate at 120 ° C for 60 seconds, and 2.38% TMA at a liquid temperature of 23 ° C.
Developing by an immersion method in an H aqueous solution for 60 seconds, followed by rinsing with pure water for 60 seconds. As a result, only the unexposed portion of the resist film was dissolved and removed in the developing solution, and a 0.2 μm line and space (L / S) negative pattern was obtained at an exposure of 6.4 mJ / cm ² . . In the obtained pattern, no deformation due to swelling and no peeling of the pattern due to insufficient adhesion were observed.

Example 4 A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Resin A1 (A1 shown in Example 1) 6.84 g (b) Crosslinking agent B1 (B1 shown in Example 2) 0.56 g (c) Photoacid generator C1 (triphenylsulfonium trifluoromethanesulfo) (Nat) (C1 shown in Example 2) 0.04 g (d) Polyhydric alcohol D1 (D1 shown below) 0.56 g (e) Diethylene glycol dimethyl ether 36.4 g

The prepared resist was spin-coated on an 8-inch silicon substrate and placed on a hot plate at 120 ° C.
For 60 seconds to form a thin film having a thickness of 0.4 μm.
This is a Nikon ArF excimer laser exposure device (NA =
0.55) through a mask. Immediately thereafter, bake on a hot plate at 130 ° C for 60 seconds,
Developing by a dipping method in a 2.38% TMAH aqueous solution at a liquid temperature of 23 ° C. for 60 seconds, followed by rinsing with pure water for 60 seconds. As a result, only the unexposed portion of the resist film was dissolved and removed in the developing solution, and 5.2 mJ / c
pattern of negative type 0.17μmL / S at an exposure amount of m ² - emission was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

Embedded image

Example 5 An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using 0.56 g of a crosslinking agent B2 (B2 shown below) instead of the crosslinking agent B1. As a result, at a light exposure of 5.8 mJ / cm ² , the light intensity was 0.1 mm.
A negative pattern of 21 μmL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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Example 6 An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using 0.56 g of a crosslinking agent B3 (B3 shown below) instead of the crosslinking agent B1. As a result, at an exposure amount of 6.0 mJ / cm ² , the light intensity was 0.1 mm.
A negative type pattern of 225 mL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 7) An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared by using a cross-linking agent B4 (B4 shown below) instead of the cross-linking agent B1. As a result, 0.3 μmL at an exposure amount of 12.8 mJ / cm ²
A negative pattern of / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

Embedded image

(Example 8) An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using a cross-linking agent B5 (B3 shown below) instead of the cross-linking agent B1. As a result, 0.35 μm at an exposure of 13.6 mJ / cm ²
An L / S negative pattern was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

Embedded image

(Example 9) A resin A2 was used instead of the resin A1.
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using (A2 shown below). In addition,
The molecular weight of the resin A2 was 6,200 (polystyrene equivalent molecular weight). As a result of the exposure experiment, a negative pattern of 0.21 μmL / S was obtained at an exposure amount of 8.8 mJ / cm ² . The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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Example 10 Resin A was used instead of resin A1
Preparation of resist using A3 (A3 shown below)
An exposure experiment was performed in the same manner as in Example 4 except for the above. What
The molecular weight of resin A3 is 32500 (polystyrene conversion
Molecular weight). In this experiment the developer was 0.11
A 9 wt% TMAH aqueous solution was used. As a result of the exposure experiment,
5.2mJ / cm ²0.275 μmL / S
A negative pattern was obtained. In the obtained pattern,
Deformation due to deformation due to swelling and poor adhesion
No screeching was seen.

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(Example 11) In place of resin A1, resin A
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using No. 4 (A4 shown below). The molecular weight of the resin A4 was 22000 (polystyrene equivalent molecular weight). 3.8 mJ / cm as a result of exposure experiment
^At a light exposure of ² , a negative pattern of 0.325 μmL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 12) In place of resin A1, resin A
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using No. 5 (A5 shown below). The molecular weight of the resin A5 was 6,100 (molecular weight in terms of polystyrene). As a result of the exposure experiment, a 0.25 μmL / S negative pattern was obtained at an exposure amount of 8 mJ / cm ² . The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

[0103]

Embedded image

(Example 13) In place of resin A1, resin A
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using No. 6 (A6 shown below). The molecular weight of the resin A6 was 8,200 (molecular weight in terms of polystyrene). In this experiment the developer was 0.119
A wt% TMAH aqueous solution was used. 3. Results of exposure experiment.
With an exposure of 6 mJ / cm ² , a negative pattern of 0.25 μmL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 14) Resin A instead of resin A1
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using No. 7 (A7 shown below). The molecular weight of the resin A6 was 6,400 (molecular weight in terms of polystyrene). As a result of the exposure experiment, 3.4 mJ / cm ²
With a light exposure of 0.19 μmL / S, a negative pattern was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

Embedded image

(Example 15) In place of resin A1, resin A
An exposure experiment was performed in the same manner as in Example 4 except that a resist was prepared using No. 8 (A8 shown below). The molecular weight of the resin A6 was 5,500 (molecular weight in terms of polystyrene). As a result of the exposure experiment, 3.6 mJ / cm ²
With this exposure amount, a negative pattern of 0.21 μmL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 16) Resin A instead of resin A1
An exposure experiment was performed in the same manner as in Example 4, except that a resist was prepared using No. 9 (A9 shown below). The molecular weight of the resin A6 was 9,500 (polystyrene equivalent molecular weight). As a result of the exposure experiment, 4.0 mJ / cm ²
With a light exposure of 0.19 μmL / S, a negative pattern was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 17) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Resin A1 (A1 shown in Example 1) 6.64 g (b) Crosslinking agent B1 (B1 shown in Example 2) 0.56 g (c) Photoacid generator C2 (β-oxocyclohexylmethyl ( (Norbornyl) trifluoromethanesulfonate) (C2 shown below) 0.24 g (d) Polyhydric alcohol D1 (D1 shown in Example 4) 0.56 g (e) Diethylene glycol dimethyl ether 36.4 g

The prepared resist was spin-coated on an 8-inch silicon substrate, and was heated to 120 ° C. on a hot plate.
For 60 seconds to form a thin film having a thickness of 0.4 μm.
This is a Nikon ArF excimer laser exposure device (NA =
0.55) through a mask. Immediately thereafter, bake on a hot plate at 130 ° C for 60 seconds,
Development was performed by a dipping method in a 2.38% TMAH aqueous solution for 60 seconds, followed by rinsing with pure water for 60 seconds. As a result, only the unexposed portion of the resist film was dissolved and removed in the developing solution, and a 0.225 mL / S negative pattern was obtained at an exposure of 14.4 mJ / cm ² . The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

[0110]

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Example 18 A resist was prepared using photoacid generator C3 (bis (tert-butylphenyl) iodonium trifluoromethanesulfonate) (C3 shown below) instead of photoacid generator C1. An exposure experiment was performed in the same manner as in Example 4. As a result, 10.
At an exposure of ² mJ / cm ² , a negative pattern of 0.19 μmL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 19) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Resin A1 (A1 shown in Example 1) 6.8 g (b) Crosslinking agent B1 (B1 shown in Example 2) 0.56 g (c) Photoacid generator C4 (N-hydroxyphthalimide-p) -Toluenesulfonic acid ester) (C4 shown below) 0.08 g (d) Polyhydric alcohol D1 (D1 shown in Example 4) 0.56 g (e) Diethylene glycol dimethyl ether 36.4 g

The prepared resist was spin-coated on an 8-inch silicon substrate, and heated on a hot plate at 120 ° C.
For 60 seconds to form a thin film having a thickness of 0.4 μm.
This is a Nikon ArF excimer laser exposure device (NA =
0.55) through a mask. Immediately thereafter, baked on a hot plate at 150 ° C for 60 seconds,
Developing by a dipping method in a 2.38% TMAH aqueous solution at a liquid temperature of 23 ° C. for 60 seconds, followed by rinsing with pure water for 60 seconds. As a result, only the unexposed portion of the resist film was dissolved and removed in the developing solution, and the resist film was 7.2 mJ / c.
pattern of negative type 0.30μmL / S at an exposure amount of m ² - emission was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 20) In the same manner as in Example 19 except that a resist was prepared using a photoacid generator C5 (bisbenzenesulfonyl) diazomethane (C5 shown below) instead of the photoacid generator C4. Then, an exposure experiment was performed.
As a result, 0.325 μm at an exposure amount of 7.4 mJ / cm ^2.
A negative pattern of mL / S was obtained. The resulting pattern did not show any deformation due to swelling and no peeling of the pattern due to insufficient adhesion.

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(Example 20) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Resin A1 (A1 shown in Example 1) 4.65 g (b) Crosslinking agent B1 (B1 shown in Example 2) 0.35 g (c) Diethylene glycol dimethyl ether 20 g

The above mixture was filtered through a 0.2 μm tetron filter to prepare a resist. This was spin-coated on a 4-inch silicon substrate and baked on a hot plate at 100 ° C. for 60 seconds to form a film having a thickness of 0.5 μm.
m was formed. The obtained membrane was used by Nidec Anelva DE
The etching rate with respect to CF ₄ gas was measured using an M451 reactive ion etching (RIE) apparatus (etching conditions: Power = 100 W, pressure = 5P).
a, gas flow rate = 30 sccm). Table 3 shows the results. As a comparative example, novolak resist (P, manufactured by Sumitomo Chemical Co., Ltd.)
FI-15A), poly (p-vinylphenol) used as a base resin for KrF resist, and poly (methyl methacrylate) coating film which is a resin having no bridging cyclic hydrocarbon group in the molecular structure. Show. The etching rate was standardized for the novolak resist. The obtained results show that the resist of the present invention has a low etching rate with respect to CF ₄ gas and is excellent in dry etching resistance. It shows that the resist of the present invention has high dry etching resistance.

(Example 21) In place of resin A1, resin A
The etching rate of the resist was measured in the same manner as in Example 20, except that the resist was prepared using the resin 2 (resin A2 shown in Example 5). Table 2 shows the results. The obtained results show that the resist of the present invention has a low etching rate with respect to CF ₄ gas and is excellent in dry etching resistance. This indicates that the resist of the present invention has high dry etching resistance.

[0118]

[Table 3]

[0119]

As is apparent from the above description,
The negative photoresist of the present invention has high transparency to ArF light, excellent dry etching resistance, and the obtained pattern is free from pattern deformation due to swelling and has little pattern peeling. Therefore, it is useful for photolithography in semiconductor device manufacturing.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a resist pattern forming method of the present invention.

[Explanation of symbols]

 1: substrate to be processed 2: resist film 3: mask 4: cross-linked area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Etsuo Hasegawa 5-7-1 Shiba, Minato-ku, Tokyo F-term within NEC Corporation (reference) 2H025 AA09 AB16 AC04 AC08 AD01 BE00 BE07 BG00 CC20 FA12 4J002 BG071 EC048 EC058 EC068 ET016 EV217 EV297 EZ007 FD146 FD207 GP03 4J100 AL16P AL16Q BA03P BA16Q BC08P BC08Q BC09P BC09Q BC12P BC12Q BC27Q CA01 CA04 CA05 CA06 DA01 HA53 JA38

Claims (10)

[Claims] 1. A polymer comprising a diol structure having a repeating unit represented by the following formula (1). Embedded image [In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 6 carbon atoms, and X represents an alicyclic alkyl group having a diol structure. ] 2. X in the formula (1) is an alicyclic alkyl group having a diol structure represented by the following formula (2), (3), (4) or (5). 2. The polymer according to 1. Embedded image [In the formula (2), n represents an integer of 0 to 3, and R ³ and R ⁴ each represent a hydrogen atom or a methyl group. ] [In the formula (3), R ⁵ represents a hydrogen atom or a methyl group. ] [In the formula (4), R ⁶ represents a hydrogen atom or a methyl group. ] [In the formula (5), R ⁷ represents a hydrogen atom or a methyl group. ] 3. It has a diol structure represented by the following formula (6):
3. The polymer according to claim 1, wherein the weight average molecular weight is 1,000 to 50,000. Embedded image [In the formula (6), R ¹ and R ² are the same as in the formula (1), X is the same as in the formulas (1) to (5), and R ⁸ is a hydrogen atom or methyl. R ⁹ is a bridged cyclic hydrocarbon group having 7 to 18 carbon atoms having a carboxyl group, R ¹⁰ is a hydrogen atom or a methyl group, R ¹¹ is a hydrocarbon group having 7 to 13 carbon atoms having a hydroxyl group, R ¹² Is a hydrogen atom or a methyl group, R ¹³ is a hydrogen atom or a carbon number of 1 to 1.
2 hydrocarbon groups. In addition, w, x, y, and z are respectively w + x + y + z = 1, 0 <w ≦ 1, 0 ≦ x <1, and 0 ≦ y
<1, 0 ≦ z <1 is an arbitrary number satisfying. ] 4. A polymer comprising a diol structure according to claim 1, a crosslinking agent comprising a compound having a functional group represented by the following formula (7): A negative-working photoresist composition comprising a photoacid generator. Embedded image [In the formula (7), R ¹⁴ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an oxoalkyl group having 3 to 6 carbon atoms. ] 5. The negative photoresist composition according to claim 4, further comprising a polyhydric alcohol compound. 6. The crosslinking agent represented by the following formulas (8) to (12):
6. The compound according to claim 4, which is at least one kind of compound.
Negative photoresist composition. Embedded image[In the formula (8), R¹⁴Is the same as in equation (7)
Yes, a₁Is 1 or 2, a₂Is 1 or 2, b₁Is 0 or
1, b₂Represents 0 or 1, respectively, and a₁+ B ₁= 2,
a₂+ B₂= 2. ][In the formula (9), R¹⁴Is the same as in equation (7)
Yes, R^FifteenRepresents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms.
Alkoxy group or oxoalkyloxy having 3 to 6 carbon atoms
Represents a group. ][In the formula (10), R¹⁴Is the same as in equation (7)
And R¹⁶Represents a hydrogen atom, a hydroxyl group,
Alkoxy group, oxoalkyloxy having 3 to 6 carbon atoms
Group, R¹⁷Is an oxygen atom, a sulfur atom, an alkyl group having 1 to 3 carbon atoms.
It represents a kylene group or a hydroxymethylene group. [Image Omitted][In the formula (11), R¹⁴Is the same as in equation (7)
And R¹⁸Represents a hydrogen atom or a methyl group. ] 7. The photoacid generator is a sulfonium salt compound represented by the following formula (13), an iodonium salt compound represented by the following formula (15), an imide compound represented by the following formula (16), or a compound represented by the following formula (17): The negative photoresist composition according to any one of claims 4 to 6, wherein the composition is at least one of the following diazo compounds. Embedded image [In the formula (13), R ¹⁹ , R ²⁰ , and R ²¹ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo aliphatic compound. cyclic alkyl group, an alkyl group, Y ^- is BF ₄ ^-,
And AsF ₆ ⁻ , SbF _6, or a counter ion represented by the following formula (14). ] [In the formula (14), Z represents C _n F _{2n + 1} (n is an integer of 1 to 6), an alkyl group, an alkyl-substituted, halogen-substituted or unsubstituted aromatic group. ] [In formula (15), R ²² and R ²³ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, an alicyclic alkyl group, a bridged cyclic hydrocarbon group, or a 2-oxo alicyclic alkyl. group, an alkyl group, Y ^- is the same as that of formula (13). ] [In the formula (16), R ²⁴ is a halogen-substituted or unsubstituted alkylene group, an alkyl-substituted, halogen-substituted or unsubstituted divalent aromatic group, R ²⁵ is a halogen-substituted or unsubstituted alkyl group, an alkyl group, It represents a halogen-substituted or unsubstituted aromatic group. Embedded image [In the formula (17), R ²⁶ and R ²⁷ each independently represent a halogen-substituted or unsubstituted alkyl group, a halogen-substituted or unsubstituted aromatic group, or an alicyclic hydrocarbon group. ] 8. The composition according to claim 4, wherein said polymer comprises 50 to 98 parts by weight, said crosslinking agent comprises 1 to 50 parts by weight, and 0.2 to 15 parts by weight of a photoacid generator which generates an acid upon exposure. A negative photoresist composition according to any one of the above. 9. A step of applying the negative photoresist composition according to claim 4 on a substrate to be processed.
A method of forming a resist pattern, comprising: exposing the negative photoresist composition to light having a wavelength of 180 to 220 nm; baking; and developing. 10. The method according to claim 9, wherein the light having a wavelength of 180 nm to 220 nm is ArF excimer laser light.