JP3237702B2 - Negative photoresist composition using polymer having 1,2-diol structure and pattern forming method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique useful for photolithography in the manufacture of semiconductor devices, and more particularly, to a negative resist suitable for lithography using far ultraviolet light of 220 nm or less, especially ArF excimer laser light as exposure light. The present invention relates to a composition and a pattern forming method using the composition.

[0002]

2. Description of the Related Art In the field of manufacturing various electronic devices that require fine processing of a half-micron order represented by a semiconductor device, there is an increasing demand for higher density and higher integration of devices. Therefore, the demand for photolithography technology for forming fine 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 when 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), a 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.

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. Now, ArF excimer laser (19)
Use of photolithography using 3 nm) has been considered.

[0005] Lithography using an excimer laser satisfies the improvement of laser cost performance because the life of the gas used for laser oscillation is short and the laser device itself is expensive. There is a need. For this reason, in addition to high resolution corresponding to miniaturization of processing dimensions, there is a high demand for high sensitivity.

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).
Examples of the negative resist include SPIE proceeding of SPIE, 108
6, pp. 34-47 (1989). E. FIG. Boga
and the like, which describe a combination of polyvinyl phenol and a melamine derivative.

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. As a result, the exposure light is not transmitted to the substrate, and a fine resist pattern cannot be formed. Therefore,
Resins used for g-line, i-line, and KrF excimer laser resists cannot be applied to photolithography using short-wavelength light of 220 nm or less.

On the other hand, dry etching resistance, which is indispensable for a resist for manufacturing a semiconductor, is obtained from a benzene ring in a resin for resists for g-line, i-line, and KrF excimer laser. Therefore, a resist for ArF excimer laser exposure does not contain a benzene ring and has etching resistance,
A transparent photoresist material is required for a wavelength of 20 nm or less.

Positive resists which are transparent to ArF excimer laser light (193 nm) and have dry etching resistance have been actively studied in recent years. In these resists, a resin having an alicyclic group is used as a base resin. A typical example is
Copolymer having adamantyl methacrylate unit [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), 465-47.
4 (1996)], a copolymer having a carboxylated tricyclodecylmethyl methacrylate unit [Maeda et al.,
SPIE Proceding
f SPIE), volume 2724, pages 377 to 398 (1
996)].

[0010]

As described above, ArF
220 nm represented by excimer laser lithography
Among the following photoresists for short wavelength light, positive photoresists combining dry etching resistance and high resolution are already known. However, a negative photoresist having both dry etching resistance and high resolution has not been found yet. Therefore, a negative resist that can be used for lithography using light of 220 nm or less such as ArF excimer laser light as exposure light, that is, Ar resist
A negative resist having dry etching resistance, resolution, and substrate adhesion (a fine pattern is not easily peeled off from a substrate) for lithography using light of 220 nm or less such as an F excimer laser beam as exposure light has been eagerly desired. I have.

[0011]

Means for Solving the Problems The inventor of the present invention has made intensive studies to achieve the above object, and has completed the present invention.
That is, the negative photoresist composition of the present invention has the general formula (1):

[0012]

Embedded image (In the general formula (1), R ¹ is a hydrogen atom or a methyl group, and G is 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ]
Decyl group, 3,4-dihydroxy-dimethyltricyclo
[5.2.1.0 ^2,6 ] decyl group, 3,4-dihydroxytetracy
Black [4.4.0.1 ^2,5 .1 ^7,10] dodecyl methyl group, 3,4-di
Hydroxy-8-methyl-tetracyclo [4.4.0.1 ^{2, 5} .1
^7,10 ] dodecylmethyl group, 2,3-dihydroxy-nor
Bornyl-methyl group, 2,3-dihydroxy-5-methyl
Le-norbornyl-methyl group, dihydroxyadamanti
Group, dihydroxyisobonyl group and dihydroxyiso
Represents at least one member selected from a bornyl group . A) a polymer containing a unit represented by:

[0013]

Embedded image Formula (5): (In Formula (5), R ¹⁰ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an oxoalkyl group having 3 to 6 carbon atoms.) It is characterized by containing a crosslinking agent composed of a compound and a photoacid generator that generates an acid upon exposure.

Further, the method of forming a resist pattern according to the present invention comprises the steps of forming a layer containing the above negative photoresist composition on a substrate to be processed, and forming the layer with a desired pattern with light having a wavelength of 180 to 220 nm. Exposing according to
The method includes a step of performing baking and a step of performing development for removing a non-exposed portion from the substrate to be processed.

According to the present invention, an ArF excimer laser can be obtained in which a negative photoresist composition has excellent transparency, and a resist pattern obtained by curing the same can have excellent dry etching resistance and resolution. It is possible to provide a technique which is extremely suitable for lithography using short-wavelength light, such as for forming a fine pattern necessary for manufacturing a semiconductor element.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the general formula (1) showing the structure of the monomer unit of the polymer contained in the composition of the present invention, G represents an alicyclic group having a 1,2-diol structure. Examples of the alicyclic group having a 1,2-diol structure include alicyclic groups represented by general formulas (2) to (4), and at least one of these is contained in a polymer. It can be contained.

[0017]

Embedded image (In the general formula (2), R ² and R ³ represent a hydrogen atom or a methyl group.)

[0018]

Embedded image (In the general formula (3), R ⁴ represents a hydrogen atom or a methyl group.)

[0019]

Embedded image (In the general formula (4), R ⁵ represents a hydrogen atom or a methyl group.) As G in the general formula (1) in the present invention,
3,4-dihydroxytricyclo [5.2.1.
0 ^2,6] decyl group, 3,4-dihydroxy - dimethyl tricyclo [5.2.1.0 ^2,6] decyl group, 3,4-dihydroxy-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecylmethyl Group, 3,
4-dihydroxy-8-methyltetracyclo [4.4.0.1
^2,5 .1 ^7,10] dodecyl methyl group, 2,3-dihydroxy -
Norbornyl-methyl group, 2,3-dihydroxy-5-
Methyl-norbornyl-methyl group, dihydroxyadama
Ethyl group, dihydroxyisobonyl group and dihydroxy
At least one selected from isobornyl groups is used
It is.

[0020]

[Table 1] Thus, the alicyclic group having a 1,2-diol structure contains two hydroxyl groups. The hydroxyl group has a property of bonding as shown in the following reaction formula (A) in the presence of a crosslinking agent having a functional group represented by the general formula (5) and an acid catalyst. Therefore,
The polymer having a 1,2-diol structure and a crosslinking agent are crosslinked by an acid to form a three-dimensional network structure. As a result, it becomes insoluble in the developer. That is, a photoresist composition comprising a combination of a polymer containing a unit represented by the general formula (1), a crosslinking agent having a functional group represented by the general formula (5), and a photoacid generator according to the present invention. Is thinned, and exposed to deep UV light such as ArF excimer laser light, an acid is generated from the photoacid generator in the exposed area, and further, the acid becomes a catalyst by heating and the polymer is cross-linked. As a result,
The exposed portion is insolubilized in the developing solution to obtain a negative pattern. Furthermore, since the group having a 1,2-diol structure has two hydroxyl groups, the degree of crosslinking is greater than that of a group having a monol structure having only one hydroxyl group. Thus, when a polymer containing a group having a 1,2-diol structure is used for a negative resist, pattern deformation due to insufficient crosslinking hardly occurs. 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 hard to be peeled off from the substrate.

[0021]

Embedded image In the present invention, examples of the polymer containing the unit represented by the general formula (1) include polymers having a monomer composition represented by the following general formulas (6) to (8).
At least one of these can be used in the preparation of the composition.

[0022]

Embedded image (In the general formula (6), R ¹ , R ² , R ³ , R ⁶ and R ⁸
Each independently represents a hydrogen atom or a methyl group, R ⁷ represents a bridged cyclic hydrocarbon group having 7 to 13 carbon atoms having a carboxyl group, R ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or Represents a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group. Also, x, y, and z indicate the composition ratio of each unit, and x +
It is a number that satisfies y + z = 1, 0 <x ≦ 1, 0 ≦ y <1, and 0 ≦ z <1. The weight average molecular weight of the polymer is 2000
~ 200000. )

[0023]

Embedded image (In the general formula (7), R ¹ , R ⁴ , R ⁶ and R ⁸ represent a hydrogen atom or a methyl group, R ⁷ represents a carboxyl group-containing bridged cyclic hydrocarbon group having 7 to 13 carbon atoms, ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group, and k, m, and n.
Represents the composition ratio of each unit, k + m + n = 1, 0 <k ≦
1, 0 ≦ m <1, 0 ≦ n <1. The weight average molecular weight of the polymer is 2,000 to 200,000. )

[0024]

Embedded image (In the general formula (8), R ¹ , R ⁵ , R ⁶ and R ⁸ represent a hydrogen atom or a methyl group, R ⁷ represents a carboxyl group-containing bridged cyclic hydrocarbon group having 7 to 13 carbon atoms, ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group, and k, m, and n.
Represents the composition ratio of each unit, k + m + n = 1, 0 <k ≦
1, 0 ≦ m <1, 0 ≦ n <1. The weight average molecular weight of the polymer is 2,000 to 200,000. Note that the above general formulas (6) to (8) do not indicate the repeating unit structure of the monomer unit but indicate the monomer composition of the polymer, and x, y, z, k, l, and m each represent the entire polymer. Represents the composition ratio of monomer units. That is, the present invention is not limited only to the case where each unit in the above formula forms a predetermined sequence. For example, a random polymer or a block polymer of these monomer units may be used. The arrangement of each unit can be changed by a polymerization method or the like.

R ⁷ in the above general formulas (6) to (8) is a bridged cyclic hydrocarbon group having 7 to 13 carbon atoms and having a carboxyl group. [5.2.1.0 ^2,6 ] decylmethyl group, carboxytricyclo [5.2.1.0 ^2,6 ] decyl group, carboxyadamantyl group, carboxynorbornyl group, carboxymethylnorbornyl group, carboxyisobornyl group, carboxytetra cyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecyl group, a carboxymethyl tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10]} dodecyl group, and the like, to be limited only to these Absent. For patterning, the unexposed negative photoresist must be dissolved in a developer. The alicyclic group having a carboxyl group has an effect of increasing the dissolution rate of a negative photoresist in a developer. Further, the alicyclic group has an effect of improving dry etching resistance.

R⁹Is a hydrogen atom, a hydrocarbon having 1 to 12 carbon atoms
A C2-C12 hydrocarbon group having an amino group or a hydroxyl group
It is. As the hydrocarbon group having 1 to 12 carbon atoms, methyl
Group, ethyl group, n-propyl group, isopropyl group, n-
Butyl group, isobutyl group, t-butyl group, cyclohexyl
Group, dimethylcyclohexyl group, tricyclo [5.2.1.
0^2,6Decyl, adamantyl, norbornyl, iso
Bornyl group, tetracyclo [4.4.0.1^2,5.1^7,10] Dodeci
But are not limited thereto.
There is no. Also, a hydrocarbon having 2 to 12 carbon atoms having a hydroxyl group.
Hydroxyethyl group, hydroxypropyl
Group, hydroxybutyl group, hydroxycyclohexyl
Group, hydroxydimethylcyclohexyl group, hydroxy
Licyclo [5.2.1.0^2,6] Decyl group, hydroxyadamanti
Group, nohydrocarbonyl group, hydroxyisobornyl
Group, hydroxytetracyclo [4.4.0.1^2,5.1^7,10] Dodeci
But are not limited thereto.
There is no. The base resin of the negative photoresist is
Must have good solubility in developing solution to resolve
There is. R⁹Is a carboxyl group
Good solubility in developer due to (carboxylic acid)
Having. R⁹When a hydrocarbon group is used for
The polymer can be adjusted to an appropriate dissolution rate by the
Can be. Also, R ⁹The hydrocarbon group of the polymer is
It is also effective in adjusting the transition point and hardness. Also, R⁹Water
When using a hydrocarbon group having 2 to 12 carbon atoms having an acid group,
Increased crosslinking efficiency due to high reactivity of hydroxyl group to crosslinking agent
Great. In addition, due to the hydroxyl group, the photoresist film substrate
Adhesion to the substrate is improved.

[0027]

[Table 2] The polymer containing the unit represented by the general formula (1) of the negative photoresist composition of the present invention can be prepared, for example, by adding a suitable radical polymerization initiator in an atmosphere of an inert gas (eg, argon or nitrogen) in dry tetrahydrofuran. (E.g., azobisisobutyronitrile (AIBN)), and can be obtained by heating and stirring at 50 to 70C for 0.5 to 12 hours. The copolymerization ratio of the polymers represented by the general formulas (6) to (8), which are the polymers containing the unit represented by the general formula (1), is as follows:
A polymer having an arbitrary copolymerization ratio can be obtained by selecting polymerization conditions such as the proportion of charged monomers. Note that this method is also described in the specification of Japanese Patent Application No. 10-093499.

The weight average molecular weight of the polymer of the negative photoresist composition of the present invention is from 1,000 to 500.
000, more preferably 5,000 to 200,000
It is. This is because if the molecular weight is too low, the polymer will have a low glass transition point, making it difficult to handle as a resist, and if the molecular weight is too high, it may be difficult to form a uniform film on the substrate.

In the present invention, as the compound containing a group represented by the general formula (5), the following general formulas (9) to (1)
The compound represented by 2) can be used.

[0030]

Embedded image (In the general formula (9), R ¹⁰ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms (specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group,
A tert-butyl group, a pentyl group, a hexyl group and the like are shown, but not limited thereto. ) Or an oxoalkyl group having 3 to 6 carbon atoms (specifically, a β-oxopropyl group, a β-oxobutyl group, a β-oxoheptyl group, a β-oxohexyl group, or the like, but is not limited thereto. ), A ₁ = 1,2, a ₂ = 1,
2, b ₁ = 0,1, b ₂ = 0,1, a ₁ + b ₁ = 2, a ₂ +
b ₂ = 2. )

[0031]

Embedded image (In the general formula (10), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
To 6 alkyl groups (specifically, a methyl group, an ethyl group,
A propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group and the like are shown, but not limited thereto. ) Or an oxoalkyl group having 3 to 6 carbon atoms (specifically, a β-oxopropyl group, a β-oxobutyl group, a β-oxoheptyl group, a β-oxohexyl group, or the like, but is not limited thereto. ), R ¹¹ represents a hydrogen atom, a hydroxyl group,
An alkoxy group having 1 to 6 carbon atoms (specifically, a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, etc. It is not limited.) Or an oxoalkyloxy group having 3 to 6 carbon atoms (specifically, β-oxopropoxy group, β-oxobutoxy group, β-oxoheptyloxy group, β-oxohexyloxy group, etc. , But is not limited to this.) )

[0032]

Embedded image (In the general formula (11), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
To 6 alkyl groups (specifically, a methyl group, an ethyl group,
A propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group and the like are shown, but not limited thereto. ) Or an oxoalkyl group having 3 to 6 carbon atoms (specifically, a β-oxopropyl group, a β-oxobutyl group, a β-oxoheptyl group, a β-oxohexyl group, or the like, but is not limited thereto. ), R ¹¹ is a hydrogen atom, a hydroxyl group or an alkoxy group having 1 to 6 carbon atoms (specifically, methoxy, ethoxy, propyl, isopropyl, butoxy, isobutoxy, tert-butoxy, pentyloxy) Represents, but is not limited to, a hexyloxy group and the like, or an oxoalkyloxy group having 3 to 6 carbon atoms (specifically, a β-oxopropyl group, a β-oxobutyl group, a β-oxoheptyl). Group, β
Represents an oxohexyl group or the like, but is not limited thereto. ), And R ¹² represents an oxygen atom, a sulfur atom, an alkylene group having 1 to 3 carbon atoms (specifically, a methylene group, an ethylene group, a propylene group, a 1-methylethylene group or the like, but is not limited thereto. Not present) or a hydroxymethylene group. )

[0033]

Embedded image (In the general formula (12), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
To 6 alkyl groups (specifically, a methyl group, an ethyl group,
A propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group and the like are shown, but not limited thereto. ) Or an oxoalkyl group having 3 to 6 carbon atoms (specifically, a β-oxopropyl group, a β-oxobutyl group, a β-oxoheptyl group, a β-oxohexyl group, or the like, but is not limited thereto. ), And R ¹³ represents a hydrogen atom, a methyl group or an ethyl group. In the compound represented by the general formula (9), which is a cross-linking agent for the negative photoresist composition of the present invention, for example, methylol urea in which R ¹⁰ is a hydrogen atom is synthesized by methylating urea with formaldehyde. It is possible. Further, a compound in which R ¹⁰ is an alkyl group or an oxoalkyl group in the general formula (9) can be obtained by treating methylol urea with a corresponding alcohol.

For example, when treated with methanol, dimethylated methylol urea [where R ¹⁰ in the general formula (9) is a methyl group (an alkyl group having 1 carbon atom)]. ], When treated with ethanol, diethylated methylol urea [in the general formula (9), R ¹⁰ is an ethyl group (an alkyl group having 2 carbon atoms)]. ], When treated with isobutanol, diisobutylated methylol urea [R ¹⁰ in the general formula (9)]
Is an isobutyl group (an alkyl group having 4 carbon atoms). ], When treated with 2-oxopropanol (also called hydroxyacetone), di-β-oxopropylated methylol urea [in the general formula (9), R ¹⁰ is a β-oxopropyl group (an oxoalkyl group having 3 carbon atoms)]. . ] Can be obtained.

The compound represented by the general formula (10)
In the general formula (10), for example, R^TenIs a hydrogen source
Child, R¹¹Is a hydrogen atom.
Chill) ethylene urea (also known as 1,3-dimethylolimi)
Dazolidone-2) is composed of urea, ethylenediamine and form
It can be obtained by reacting an aldehyde.
In the general formula (10), R^TenIs an alkyl group or
Is an oxoalkyl group, R ¹¹Is a hydrogen atom,
1,3-bis (hydroxymethyl) ethyleneurea vs.
Can be obtained by treatment with the corresponding alcohol
it can.

For example, when treated with methanol, 1,3-
Bis (methoxymethyl) ethylene urea [General formula (1
0) wherein R ¹⁰ is a methyl group (alkyl group having 1 carbon atom) and R ¹¹ is a hydrogen atom. ], When treated with ethanol, 1,3-bis (ethoxymethyl) ethylene urea [In the general formula (10), R ¹⁰ is an ethyl group (2 carbon atoms)
And R ¹¹ is a hydrogen atom. And 1,3-bis (isobutoxymethyl) ethylene urea when treated with isobutanol [in the general formula (10), R ¹⁰ is an isobutyl group (alkyl group having 4 carbon atoms), and R ¹¹ is a hydrogen atom. And 2-oxopropanol (also called hydroxyacetone) to give 1,3-bis (β-oxopropoxymethyl) ethyleneurea [general formula (10)
Wherein R ¹⁰ is a 2-oxopropyl group (an oxoalkyl group having 3 carbon atoms), and R ¹¹ is a hydrogen atom. ] Can be obtained.

In the general formula (10), 1,3-bis (hydroxymethyl) -4,5-bis (hydroxy) ethylene urea (also called 1,3-dimethylol) wherein R ¹⁰ is a hydrogen atom and R ¹¹ is a hydroxyl group -4,5-dihydroxyimidazolidone-2) can be synthesized by reacting urea with glyoxal and then methylolating with formaldehyde. In the general formula (10), R ¹⁰
Is an alkyl group or an oxoalkyl group, and the compound wherein R ¹¹ is an alkoxy group or an oxoalkoxy group is
It can be obtained by treating 1,3-bis (hydroxymethyl) -4,5-bis (hydroxy) ethyleneurea with the corresponding alcohol.

For example, when treated with methanol, 1,3-
Bis (methoxymethyl) -4,5-bis (methoxy) ethyleneurea [In the general formula (10), R ¹⁰ is a methyl group (an alkyl group having 1 carbon atom), and R ¹¹ is a methoxy group (an alkoxy group having 1 carbon atom) What is. And treatment with ethanol gives 1,3-bis (ethoxymethyl) -4,5-
Bis (ethoxy) ethylene urea [in the formula (10), R ¹⁰ is an ethyl group (an alkyl group having 2 carbon atoms), and R ¹¹ is an ethoxy group (an alkoxy group having 2 carbon atoms). ], When treated with isopropanol, 1,3-bis (isopropoxymethyl) -4,5-bis (isopropoxy) ethyleneurea [In the general formula (10), R ¹⁰ is an isopropyl group (an alkyl group having 3 carbon atoms); ¹¹ is a propyloxy group (alkoxy group having 3 carbon atoms). ], When treated with tert-butanol, 1,3-bis (tert-butoxymethyl) -4,5-bis (tert-butoxy) ethyleneurea [In the general formula (5), R ¹⁰ is a tert-butyl group (4 carbon atoms) And R ¹¹ is a tert-butoxy group (alkoxy group having 4 carbon atoms). ], 2-oxopropanol (also known as hydroxyacetone) gives 1,3-bis (β
-Oxopropoxymethyl) -4,5-bis (β-oxopropoxy) ethylene urea [In the general formula (10), R ¹⁰ is a β-oxopropoxypyryl group (an oxoalkyl group having 3 carbon atoms), and R ¹¹ is a β -An oxopropoxy group (an oxoalkoxy group having 3 carbon atoms); ] Can be obtained.

Further, a compound represented by the general formula (11)
Is, for example, R in the general formula (11) ^Ten, R¹¹Is a hydrogen source
Child, R¹²Is a methylene group, 1,3-bis (hydroxy
Methyl) -tetrahydro-2 (1H) pyrimidinone
Urea and propylene diamine,
Can be obtained by reacting with
You. In the general formula (11), R^TenIs an alkyl group,
R¹¹Is a hydrogen atom, R¹²Is a methylene group,
3-bis (hydroxymethyl) -tetra-hydro-2
(1H) Pyrimidinone treated with corresponding alcohol
Can be obtained.

For example, when treated with methanol, dimethylated 1,3-bis (hydroxymethyl) -tetrahydro-2 (1H) pyrimidinone [R ¹⁰ in general formula (11)]
Is a methyl group (an alkyl group having 2 carbon atoms), R ¹¹ is a hydrogen atom, and R ¹² is a methylene group (an alkylene group having 1 carbon atom). ], Treated with ethanol to give diethylated 1,3
-Bis (hydroxymethyl) -tetrahydro-2 (1
H) Pyrimidinone [In the general formula (11), R ¹⁰ is an ethyl group (an alkyl group having 2 carbon atoms), R ¹¹ is a hydrogen atom, R ¹²
Is a methylene hydrogen atom (alkylene group having 1 carbon atom). ], Butylated with isobutanol,
3-bis (hydroxymethyl) -tetrahydro-2 (1
H) pyrimidinone [In the general formula (11), R ¹⁰ is an isobutyl group (an alkyl group having 4 carbon atoms), R ¹¹ is a hydrogen atom,
Those wherein R ¹² is a methylene group (alkylene group having 1 carbon atom)). ] Can be obtained.

In the general formula (11), R ¹⁰ and R ¹¹
Is a hydrogen atom, and R ¹² is an oxygen atom. The dimethyloluron can be obtained by reacting urea with 4 times the formaldehyde thereof. 1,3-bis (hydroxymethyl) -tetrahydro-5-hydroxy-2 (H) pyrimidinone in which R ¹⁰ and R ¹¹ are hydrogen atoms and R ¹² is a hydroxymethylene group is reacted with urea and 2-hydroxypropylenediamine. And further reacted with formaldehyde.

In the case of the compound represented by the general formula (12), for example, in the general formula (12), R ¹⁰ is a hydrogen atom,
1,3,4,6-tetrakis (hydroxymethyl) glycoluril wherein R ¹³ is a hydrogen atom (also known as 1,3,4,
6-tetrakis (hydroxymethyl) acetylene urea, tetramethylolated greoxazole diurein
Can be synthesized by reacting glyoxazole with a 2-fold molar amount of urea, and then converting it to methylol with formaldehyde. When R ¹⁰ is an alkyl group or an oxoalkyl group and R ¹³ is a hydrogen atom in the general formula (12), 1,3,4,6-tetrakis (hydroxymethyl) glycoluril is treated with a corresponding alcohol. Can be obtained.

For example, when treated with methanol,
4,6-tetrakis (methoxymethyl) glycoluril [In the general formula (12), R ¹⁰ is a methyl group (C 1
And R ¹³ is a hydrogen atom. When treated with ethanol, 1,3,4,6-tetrakis (ethoxymethyl) glycoluril [in the formula (12), R ¹⁰ is an ethyl group (alkyl group having 2 carbon atoms), and R ¹³ is a hydrogen atom] . When treated with isobutanol, 1,3,4,6-tetrakis (isobutoxymethyl) glycoluril [in the general formula (12), R ⁸ is an isobutyl group (an alkyl group having 4 carbon atoms), and R ¹³ is a hydrogen atom. some stuff. ], 2,3,4,6-tetrakis (β-oxopropoxymethyl) glycoluril when treated with 2-oxopropanol (also known as hydroxyacetone) [In the general formula (12), R ¹⁰ is a β-oxopropyl group (carbon number) Oxoalkyl group 3), wherein R ¹³ is a hydrogen atom. ] Can be obtained.

The photoacid generator of the resist composition of the present invention comprises
It is desirable to use 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 Any photoacid generator may be used as long as the solution can form a uniform coating film by a film forming method such as spin coating. Moreover, you may use individually or in mixture of 2 or more types. Examples of usable photoacid generators include sulfonium salt compounds represented by the general formula (14),
An iodonium salt compound represented by the general formula (16), a succinimide derivative represented by the general formula (17),
The diazo compound represented by 8), 2,6-dinitrobenzyl esters, disulfone compounds and the like can be used.
Examples of these are the Journal of the Organic Chemistry (Journal of the Organic Chemistry).
rganic Chemistry), 43, 15
No., pp. 3055-3058 (1978). V. JV Crivello et al., Triphenylsulfonium salt derivative, Journal of the Polymer Science (Journal of).
the Polymer Science), 56
Vol., P. 383-395 (1976). V. JV Crivello et al., A diphenyliodonium salt derivative; an alkylsulfonium salt derivative such as cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate disclosed in JP-A-7-28237;
Β-oxocyclohexylmethyl (2-norbornyl) sulfonium disclosed in US Pat.
There are sulfonium salt compounds having a bridged cyclic alkyl group such as trifluoromethanesulfonate. In addition, 2,6-dinitrobenzyl esters [O. O. Nalamasu et al., SPIE Procedure.
Ding, 1262, 32 (1990)], 1,
2,3-tri (methanesulfonyloxy) benzene [Takumi Ueno et al., Proceeding of PME '89, Kodansha, pp. 413-424 (1990)], disulfone compounds and the like.

[0045]

Embedded image [In the formula (14), R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent an alkyl-substituted, halogen-substituted or unsubstituted aromatic group,
Represents an alicyclic group, a bridged cyclic hydrocarbon group, a 2-oxo alicyclic group or an alkyl group, and Y ⁻ is BF ₄ ⁻ , AsF ₆ ⁻ , Sb
F ₆ ^- or the formula (15): Z-SO ₃ ^- (general formula (15) in Z is C _n F _{2n +} 1 _(n is an integer of 1 to 6), an alkyl group or an alkyl-substituted or halogen-substituted or unsubstituted Represents an aromatic group.). ]

[0046]

Embedded image (In the formula (16), R ¹⁷ and R ¹⁸ are each independently an alkyl-substituted or halogen-substituted or unsubstituted aromatic group,
An alicyclic group, a bridged cyclic alicyclic group, a 2-oxo alicyclic group, a 2-oxo bridged cyclic hydrocarbon group or an alkyl group;
BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ or the above general formula (15)
Represents a counter ion represented by )

[0047]

Embedded image (In the general formula (17), R ¹⁹ represents a halogen-substituted or unsubstituted alkyl group or an alkyl-substituted or halogen-substituted or unsubstituted divalent aromatic group, and R ²⁰ represents a halogen-substituted or unsubstituted alkyl group or an alkyl group. Or a halogen-substituted or unsubstituted aromatic group.)

[0048]

Embedded image (In the general formula (18), R ²¹ and R ²² each independently represent an alkyl group, an alkyl-substituted or halogen-substituted or unsubstituted aromatic group, an alkyl group, an alicyclic hydrocarbon group or a bridged cyclic hydrocarbon group. In addition, when the negative photoresist composition of the present invention contains a polyhydric alcohol (dihydric or higher alcohol), the resolution may be improved in some cases. This is because a polyhydric alcohol having high reactivity with the crosslinking agent acts as a crosslinking accelerator. Examples of the polyhydric alcohol used in the present invention include 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, D-cellobiose, cellulose, 1,5-decalindiol, glucose, galactose, lactose, maltose, mannose, mannitol and the like. Seeds can be used.

The content of the polymer containing the unit represented by the general formula (1) in the negative photoresist composition of the present invention is usually from 50 to 98 based on 100 parts by weight of all the components including itself. Parts by weight, preferably 70 to 95 parts by weight. If the content is less than 50 parts by weight, it may be difficult to form a uniform film. If the amount is more than 98 parts by weight, the amount of the cross-linking agent and the photoacid generator that can be introduced is inevitably reduced. The content of the cross-linking agent is usually 1 to 50 parts by weight based on 100 parts by weight of all components including itself.
Parts by weight, preferably 10 to 30 parts by weight. If the content is less than 1 part by weight, the polymer may not be sufficiently crosslinked and a pattern may not be obtained. If the amount is more than 50 parts by weight, it is difficult to form a uniform film, and the transparency of the thin film may decrease. In addition, the content of the polymer is insufficient, and sufficient etching resistance may not be obtained.

The content of the photoacid generator is usually from 0.2 to 15 parts by weight based on 100 parts by weight of all components including itself.
Parts by weight, preferably 0.5 to 10 parts by weight. When the content is less than 0.2 parts by weight, the sensitivity of the negative resist composition of the present invention is remarkably lowered, and it may be difficult to form a pattern. . On the other hand, if the amount exceeds 15 parts by weight, it may be difficult to form a uniform coating film, and there may be a problem that a residue (scum) is easily generated after development. . When a polyhydric alcohol is contained, the amount is usually 0.2 to 100 parts by weight based on all components including itself.
When it is contained in an amount of 20 parts by weight, the resolution is improved.

Preferred as the solvent used in the present invention are those in which the negative resist composition of the present invention is sufficiently dissolved,
Any solvent may be used as long as the solution is an organic solvent capable of forming a uniform coating film by a method such as a spin coating method. Moreover, you may use individually or in mixture of 2 or more types. Specifically, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monoethyl ether acetate ( 1-methoxy-2-acetoxypropane), methyl lactate, ethyl lactate, 2-methoxybutyl acetate, 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, Examples include, but are not limited to, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, and the like.

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, if necessary.

The negative resist composition of the present invention uses, as a base resin, a polymer having an alicyclic group, which is known to provide high dry etching resistance. Further, since this polymer does not have a 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, and has both high transparency and high dry etching resistance to light having a short wavelength of 220 nm or less such as ArF excimer laser light.

The present invention also provides a method for forming a negative photoresist pattern on a substrate to be processed by using the above negative photoresist material. FIG. 1 shows a method of forming a negative pattern according to the present invention. First, as shown in FIG. 1 (A), a negative photoresist material of the present invention is applied onto a substrate 1 to be processed,
The resist film 2 is formed by performing a pre-bake process using a heating means such as a hot plate for 240 seconds. next,
As shown in FIG. 1B, the resist film 2 is selectively exposed using an exposure device. After the exposure, the resist 2 film is subjected to a heat treatment. As a result, in the exposed area 4, the resin is crosslinked. Finally, as shown in FIG. 1 (D), only an unexposed portion of the resist film 2 is selectively dissolved and removed with an alkali developing solution such as an aqueous solution of tetramethylammonium hydroxide (TMAH) to form a negative pattern. You.

The negative photoresist material of the present invention is Ar
It has high transparency to light of 220 nm or less, such as F excimer laser light, and has resistance to dry etching and resolution, so that it can be used as a new negative photoresist material for manufacturing semiconductor devices.

[0056]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. Incidentally, the polymer used in each of the following examples,
It is a random polymer having the following monomer unit composition and can be obtained by the methods described in Production Examples 1 to 9.

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image The crosslinking agent was selected from the following compounds.

[0060]

Embedded image

[0061]

Embedded image Further, the photoacid generator and the polyhydric alcohol were selected from the following compounds.

[0062]

Embedded image (Production Example 1) Production method of polymer A1 In a 100 ml eggplant flask equipped with a reflux tube, 4 g of 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ] decyl acrylate and carboxytetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ]
4.72 g of dodecyl acrylate was dissolved in 50 ml of dry tetrahydrofuran, and 110 mg of azobisisobutyronitrile (AIBN) was added thereto, followed by stirring at 60 to 65 ° C under an argon atmosphere. After cooling for 2 hours, the reaction mixture was poured into 800 ml of ligroin / ether (1/1), and the deposited precipitate was separated by filtration. Further, reprecipitation purification was performed once again to obtain 4.8 g of the desired product (yield 55).
%). The copolymerization ratio at this time was 50:50 from the integration ratio of ¹ H-NMR (x = 0.65, y = 0.3
5). The weight average molecular weight (Mw) was determined by GPC analysis.
Is 8300 (in terms of polystyrene), dispersity (Mw / M
n) was 1.98.

[0063] (Production Example 2) Similar to the manufacturing method in Production Example 1 of Polymer A2, provided that 3,4-dihydroxy tricyclo [5.2.1.0 ^{2, 6]} decyl acrylate 3g carboxymethyl tetracyclo [4.4.0.1 ^{2 , 5.1 7,10]} dodecyl acrylate 8.24 g, were synthesized using AIBN138mg. Yield 51%, Mw = 9300, Mw / Mn = 1.7
9.

[0064] (Production Example 3) in the same manner as the method in Production Example 1 of Polymer A3, provided that 3,4-dihydroxy tricyclo [5.2.1.0 ^{2, 6]} decyl methacrylate 3g carboxymethyl tetracyclo [4.4.0.1 ^{2 , 5.1 7,10]} dodecyl methacrylate 8.16 g, were synthesized using AIBN138mg. Yield 65%, Mw = 28600, Mw / Mn =
2.22.

(Production Example 4) Method for producing polymer A4 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ] acrylate 4 in a 100 ml eggplant flask equipped with a reflux tube.
g, carboxy tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecyl methacrylate 2.9 g, tricyclodecyl [5.2.
1.0 ^2,6 ] acrylate (1.74 g) was dissolved in dry tetrahydrofuran (36 ml), AIBN (184 mg) was added thereto, and the mixture was stirred at 60 to 65 ° C. under an argon atmosphere. After cooling for 2 hours, the reaction mixture was allowed to cool with ligroin / ether (1/1).
1) The mixture was poured into 1000 ml, and the deposited precipitate was separated by filtration. Further, the target substance was purified by reprecipitation purification again to obtain 5.6.
2 g were obtained (65% yield). Mw = 1500, Mw / M
n = 2.03.

(Production Example 5) Method for producing polymer A5 In the same manner as in Production Example 1, except that 3,4-dihydroxytetra
Cyclo [4.4.0.1^2,5.1 ^7,10] Dodecyl methyl acrylate
5 g and carboxytetracyclo [4.4.0.1^2,5.1^7,10]
Using 5 g of dodecyl acrylate and 117 mg of AIBN
And synthesized. Yield 62%, Mw = 6100, Mw / Mn
= 1.83.

[0067] (Production Example 6) in 100ml eggplant flask equipped with a manufacturing method reflux condenser of the polymer A6, dihydroxy norbornyl methyl acrylate 6 g, t-butoxycarbonyl tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 ] 5.24 g of dodecyl acrylate in dry tetrahydrofuran 45
Then, 154 mg of AIBN was added thereto, and the mixture was stirred at 60 to 65 ° C under an argon atmosphere. After cooling for 2.5 hours, the reaction mixture was ligroin / ether (1/1).
The mixture was poured into 1000 ml, and the deposited precipitate was separated by filtration. Furthermore,
The precipitate was purified again to obtain 7.8 g of the desired product (yield 70%). Mw = 13800, Mw / Mn =
2.12.

[0068] (Production Example 7) 100 ml eggplant type flask 3,4-dihydroxy tricyclo [5.2.1.0 ^{2, 6]} that with a manufacturing method reflux condenser of the polymer A7 decyl acrylate 10 g, carboxy tetracyclo [4.4.0.1 ^{2 , 5} .1 ^7,10 ]
10.74 g of dodecyl methacrylate and 0.334 g of methyl methacrylate were dissolved in 80 ml of dry tetrahydrofuran, 255 mg of AIBN was added thereto, and the mixture was stirred at 60 to 65 ° C. under an argon atmosphere. After cooling for 2 hours, the reaction mixture was ligroin / ether (1/1) 1000 m
and the precipitated precipitate was filtered off. Further, re-precipitation purification was performed once again to obtain 14.33 g of the desired product (yield: 68%). Mw = 9500, Mw / Mn = 2.37.

(Production Example 8) Production method of polymer A8 In a 100 ml eggplant flask equipped with a reflux tube, 10 g of 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ] decyl acrylate and 1.54 g of methacrylic acid were dried in tetrahydrofuran. The solution was dissolved in 45 ml, AIBN (195 mg) was added thereto, and the mixture was stirred at 60 to 65 ° C under an argon atmosphere. After cooling for 2 hours, the reaction mixture was allowed to cool with ligroin / ether (1/1).
1) The mixture was poured into 1000 ml, and the deposited precipitate was separated by filtration. Further, the target substance was purified by another reprecipitation purification to obtain 8.5.
2 g were obtained (74% yield). Mw = 13200, Mw / M
n = 2.85.

(Production Example 9) Production method of polymer A9 6.75 g of 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ] decyl acrylate and carboxytetracyclo [4.4. 0.1 ^2,5 .1
^[7,10 ] dodecyl methacrylate (5 g) and hydroxytricyclo [5.2.1.0 ^2,6 ] decyl acrylate (1.15 g) were dissolved in dry tetrahydrofuran (50 ml).
N-170mg, 60-65 ° C under argon atmosphere
With stirring. After cooling for 2 hours, the reaction mixture was poured into 1000 ml of ligroin / ether (1/1), and the deposited precipitate was separated by filtration. Further, re-precipitation purification was performed once again to obtain 5.82 g of the desired product (yield: 45%). Mw = 54
00, Mw / Mn = 2.65.

Example 1 A negative photoresist composition (hereinafter simply referred to as a resist) having the following composition was prepared. The following operations were performed under a yellow lamp. (A) Polymer A1: 4.6 g (b) Crosslinker B1: 0.35 g (c) Photoacid generator C1 (triphenylsulfonium trifluoromethanesulfonate): 0.05 g (d) Ethyl lactate: 31 g The weight average molecular weight of the polymer A1 (the same applies hereinafter) is 83
00. Here, the molecular weight is LC-9 manufactured by Shimadzu Corporation.
A (column: KF-80M manufactured by Showa Denko) was measured by gel permeation chromatography (GPC), and determined as a polystyrene equivalent molecular weight.

The mixture of the above components was filtered with a 0.2 μm tetron filter to prepare a resist. This was spin-coated on a 3-inch quartz substrate and heated on a hot plate at 100 ° C. for 60 seconds to form a thin film having a thickness of 0.5 μm. 193.4 nm light of this thin film (ArF
The transmittance at the center wavelength of the excimer laser light) is 63.
5%. This is sufficient transparency as a single-layer resist.

(Example 2) The resist prepared in Example 1 was spin-coated on a 4-inch silicon substrate and heated on a hot plate at 100 ° C for 60 seconds to form a film having a thickness of 0.5
A μm thin film was formed. This was left standing in a contact-type exposure experiment machine sufficiently purged with nitrogen. A mask in which a pattern of chrome was drawn on a quartz plate was adhered to the resist film, and ArF excimer laser light was irradiated through the mask. Immediately thereafter, baked on a hot plate at 120 ° C. for 60 seconds, and baked with a 2.38% aqueous TMAH solution at a liquid temperature of 23 ° C.
Development was performed by the immersion method for 2 seconds, followed by rinsing with pure water for 60 seconds. As a result, only the unexposed portion of the resist film is dissolved and removed in the developing solution, and 7.2
At an exposure of mJ / cm ² , a negative pattern of 0.25 μmL / S was obtained.

Example 3 A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Polymer A1: 4.25 g (b) Crosslinker B1: 0.35 g (c) Photoacid generator C1 (triphenylsulfonium trifluoromethanesulfonate): 0.05 g (d) Polyhydric alcohol D1: 0 0.35 g (e) Diethylene glycol dimethyl ether: 31 g The prepared resist was spin-coated on a 4-inch silicon substrate and heated on a hot plate at 100 ° C. for 60 seconds to form a thin film having a thickness of 0.5 μm. This was left standing in a contact-type exposure experiment machine sufficiently purged with nitrogen. A mask in which a pattern of chrome was drawn on a quartz plate was adhered to the resist film, and ArF excimer laser light was irradiated through the mask. Immediately thereafter, baked on a hot plate at 120 ° C. for 60 seconds, and 2.38% TM at a liquid temperature of 23 ° C.
Developing by an immersion method in an AH aqueous solution for 60 seconds, followed by rinsing with pure water for 60 seconds.
As a result, only the unexposed portions of the resist film were dissolved and removed in the developing solution, and 0.20 μmL / S at an exposure of 3.5 mJ / cm ^2.
A negative pattern was obtained.

Example 4 An exposure experiment was performed in the same manner as in Example 3, except that 0.35 g of the crosslinking agent B2 was used instead of the crosslinking agent B1 to prepare a resist. As a result, 9.3
At an exposure of mJ / cm ² , a negative pattern of 0.225 μmL / S was obtained.

Example 5 An exposure experiment was carried out in the same manner as in Example 3, except that the resist was adjusted using a crosslinking agent B3 instead of the crosslinking agent B1. As a result, 10.2 mJ / cm
^At a light exposure of ² , a negative pattern of 0.3 μmL / S was obtained.

Example 6 An exposure experiment was carried out in the same manner as in Example 3, except that the resist was adjusted using a crosslinking agent B4 instead of the crosslinking agent B1. As a result, a negative pattern of 0.25 μmL / S was obtained at an exposure dose of 27 mJ / cm ² .

Example 7 An exposure experiment was performed in the same manner as in Example 3, except that the resist was adjusted using a crosslinking agent B5 instead of the crosslinking agent B1. As a result, 17.5 mJ / cm
^At a light exposure of ² , a negative pattern of 0.4 μmL / S was obtained.

Example 8 A resist was prepared in the same manner as in Example 3 except that the polymer A2 was used instead of the polymer A1, and the transmittance was measured. The molecular weight of the polymer A2 is 93
The molecular weight was 00 (polystyrene equivalent molecular weight: 0). As a result of the exposure experiment, 0.25 μmL at an exposure amount of 15.2 mJ / cm ²
A negative pattern of / S was obtained.

Example 9 In the same manner as in Example 3, except that the polymer A3 was used instead of the polymer A1, and 2.38 wt%
0.119wt% TMAH instead of% TMAH aqueous solution
A resist was prepared using an aqueous solution, and an exposure experiment was performed.
The transmittance was measured. The molecular weight of the polymer A3 was 286.
00 (polystyrene equivalent molecular weight). As a result of the exposure experiment, 0.25 μmL / S at an exposure amount of 7.3 mJ / cm ²
A negative pattern was obtained.

Example 10 An exposure experiment was performed in the same manner as in Example 3 except that the resist was adjusted using polymer A4 instead of polymer A1. The molecular weight of the polymer A4 was 11,500 (polystyrene equivalent molecular weight). As a result of the exposure experiment, 0.25 μm at an exposure amount of 4.5 mJ / cm ²
An L / S negative pattern was obtained.

Example 11 An exposure experiment was carried out in the same manner as in Example 3, except that the polymer A5 was used instead of the polymer A1 to prepare a resist. The molecular weight of the polymer A5 is 6
It was 100 (polystyrene equivalent molecular weight). As a result of the exposure experiment, a negative pattern of 0.25 μmL / S was obtained at an exposure amount of 8 mJ / cm ² .

Example 12 An exposure experiment was carried out in the same manner as in Example 3, except that the polymer A6 was used instead of the polymer A1 to prepare a resist. The molecular weight of the polymer A6 was 13,800 (molecular weight in terms of polystyrene). As a result of an exposure experiment, 0.225 μ at an exposure amount of 3.8 mJ / cm ^2.
A negative pattern of mL / S was obtained.

Example 13 An exposure experiment was conducted in the same manner as in Example 3, except that the polymer A7 was used instead of the polymer A1 to prepare a resist. The molecular weight of the polymer A7 was 7,200 (polystyrene equivalent molecular weight). As a result of the exposure experiment, 0.25 μmL at an exposure amount of 6.2 mJ / cm ²
A negative pattern of / S was obtained.

Example 14 An exposure experiment was carried out in the same manner as in Example 3, except that the polymer A8 was used instead of the polymer A1 to prepare a resist. The molecular weight of the polymer A8 was 13,800 (polystyrene equivalent molecular weight). As a result of an exposure experiment, 0.225 μ at an exposure amount of 3.8 mJ / cm ^2.
A negative pattern of mL / S was obtained.

Example 15 An exposure experiment was carried out in the same manner as in Example 3, except that the resist was adjusted using polymer A9 instead of polymer A1. The molecular weight of the polymer A9 was 8,150 (polystyrene equivalent molecular weight). As a result of the exposure experiment, 0.20 μmL at an exposure amount of 4.5 mJ / cm ²
A negative pattern of / S was obtained.

(Example 16) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Polymer A1: 4.05 g (b) Crosslinker B1: 0.35 g (c) Photoacid generator C2 (β-oxocyclohexylmethyl (norbornyl) trifluoromethanesulfonate): 0.25 g (d) Poly Polyhydric alcohol D1: 0.35 g (e) Diethylene glycol dimethyl ether: 23 g The prepared resist is spin-coated on a 4-inch silicon substrate and heated on a hot plate at 100 ° C. for 60 seconds to form a thin film having a thickness of 0.5 μm. did. This was left standing in a contact-type exposure experiment machine sufficiently purged with nitrogen. A mask in which a pattern of chrome was drawn on a quartz plate was adhered to the resist film, and ArF excimer laser light was irradiated through the mask. Immediately thereafter, baked on a hot plate at 120 ° C. for 60 seconds, and 2.38% TM at a liquid temperature of 23 ° C.
Developing by an immersion method in an AH 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 0.225 μmL at an exposure amount of 17.7 mJ / cm ^2.
A negative pattern of / S was obtained.

Example 17 A resist was prepared in the same manner as in Example 3, except that the photoacid generator C3 (bis (tert-butylphenyl) iodonium trifluoromethanesulfonate) was used instead of the photoacid generator C1. And an exposure experiment was performed. As a result, 0.45 at an exposure of 15 mJ / cm ^2.
A negative pattern of μmL / S was obtained.

(Example 18) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Polymer A1: 4.15 g (b) Crosslinker B1: 0.35 g (c) Photoacid generator C4 (N-hydroxysuccinimide-
(p-toluenesulfonic acid ester): 0.15 g (d) Polyhydric alcohol D1 (D1 shown in Example 3):
0.35 g (e) Diethylene glycol dimethyl ether: 23 g The prepared resist was spin-coated on a 4-inch silicon substrate, and heated on a hot plate at 100 ° C. for 60 seconds to form a thin film having a thickness of 0.5 μm. This was left standing in a contact-type exposure experiment machine sufficiently purged with nitrogen. A mask in which a pattern of chrome was drawn on a quartz plate was adhered to the resist film, and ArF excimer laser light was irradiated through the mask. Immediately thereafter, baked on a hot plate at 140 ° C for 60 seconds, and 2.38% TM at 23 ° C.
Developing by an immersion method in an AH aqueous solution for 60 seconds, followed by rinsing with pure water for 60 seconds.
As a result, only the unexposed portions of the resist film were dissolved and removed in the developing solution, and a 0.25 μmL / S negative pattern was obtained at an exposure dose of 22 mJ / cm ² .

(Embodiment 19) In the same manner as in Embodiment 15,
However, an exposure experiment was performed by adjusting the resist using a photoacid generator C5 (bisbenzenesulfonyl) diazomethane) instead of the photoacid generator C4. As a result, 8.5 mJ / cm ²
A negative pattern of 0.40 .mu.mL / S was obtained at the exposure amount.

(Example 20) A resist having the following composition was prepared. The following experiment was performed under a yellow lamp. (A) Polymer A1: 4.65 g (b) Crosslinking agent B1 (B1 shown in Example 1): 0.35
g (c) Ethyl lactate: 31 g A mixture of the above components was filtered through a 0.2 μm tetron filter to prepare a resist. This was spin-coated on a 3-inch silicon substrate and baked on a hot plate at 100 ° C. for 60 seconds to form a film having a thickness of 0.7 μm.
m was formed. The obtained membrane was used by Nidec Anelva DE
The etching rate for 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 polymer of KrF resist, and poly (methyl methacrylate) coating film which is a polymer having no bridged cyclic hydrocarbon group in its molecular structure. The results are also shown. The etching rate was standardized for the novolak resist. The obtained results indicate 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 the same manner as in Example 20,
However, the etching rate was also measured for a resist using the polymer A2 instead of the polymer A1. Table 2 shows the results.
Shown in From the results obtained, the resist of the present invention was CF ₄
It was shown that the etching rate with respect to the gas was slow and the dry etching resistance was excellent. This indicates that the resist of the present invention has high dry etching resistance.

(Example 22) In the same manner as in Example 20,
However, the etching rate was also measured for a resist using the polymer A3 instead of the polymer A1. Table 2 shows the results.
Shown in From the results obtained, the resist of the present invention was CF ₄
It was shown that the etching rate with respect to the gas was slow and the dry etching resistance was excellent. This indicates that the resist of the present invention has high dry etching resistance.

[0094]

[Table 3]

[0095]

As is apparent from the above description,
The negative photoresist material of the present invention has excellent transparency and can be used for lithography using short-wavelength light such as ArF excimer laser. It can be used for forming a fine pattern necessary for the above.

[Brief description of the drawings]

FIGS. 1A to 1D are views showing main steps in a method for forming a resist pattern according to the present invention.

[Explanation of symbols]

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

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/027 H01L 21/30 502R (72) Inventor Etsuo Hasegawa 5-1-1 Shiba, Minato-ku, Tokyo NEC Corporation (56) References JP-A-11-292822 (JP, A) JP-A-10-274853 (JP, A) JP-A-8-240911 (JP, A) JP-A-7-252324 (JP, A) ( 58) Surveyed field (Int.Cl. ⁷ , DB name) G03F 7/038 601

Claims (10)

(57) [Claims] 1. A polymer having a unit represented by the general formula (1), a crosslinking agent comprising a compound having a functional group represented by the general formula (5), and a photoacid generator which generates an acid upon exposure to light. And a negative photoresist composition. Embedded image (In the general formula (1), R ¹ is a hydrogen atom or a methyl group, and G is 3,4-dihydroxytricyclo [5.2.1.0 ^2,6 ]
Decyl group, 3,4-dihydroxy-dimethyltricyclo
[5.2.1.0 ^2,6 ] decyl group, 3,4-dihydroxytetracy
Black [4.4.0.1 ^2,5 .1 ^7,10] dodecyl methyl group, 3,4-di
Hydroxy-8-methyl-tetracyclo [4.4.0.1 ^{2, 5} .1
^7,10 ] dodecylmethyl group, 2,3-dihydroxy-nor
Bornyl-methyl group, 2,3-dihydroxy-5-methyl
Le-norbornyl-methyl group, dihydroxyadamanti
Group, dihydroxyisobonyl group and dihydroxyiso
Represents at least one member selected from a bornyl group . ) (In the general formula (5), R ¹⁰ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an oxoalkyl group having 3 to 6 carbon atoms.) 2. The negative photoresist composition according to claim 1, further comprising a polyhydric alcohol compound. 3. The negative photoresist composition according to claim 1, wherein G in the general formula (1) is at least one of the general formulas (2) to (4). Embedded image (In the general formula (2), R ² and R ³ each independently represent a hydrogen atom or a methyl group.) (In the general formula (3), R ⁴ represents a hydrogen atom or a methyl group.) (In the general formula (4), R ⁵ represents a hydrogen atom or a methyl group.) 4. The negative photoresist composition according to claim 1, wherein the polymer is at least one of the polymers represented by the general formulas (6) to (8). Embedded image (In the general formula (6), R ¹ , R ² , R ³ , R ⁶ and R ⁸
Each independently represents a hydrogen atom or a methyl group, R ⁷ represents a bridged cyclic hydrocarbon group having 7 to 13 carbon atoms having a carboxyl group, R ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or Represents a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group. Also, x, y, and z indicate the composition ratio of each unit, and x +
It is a number that satisfies y + z = 1, 0 <x ≦ 1, 0 ≦ y <1, and 0 ≦ z <1. The weight average molecular weight of the polymer is 2000
~ 200000. ) (In the general formula (7), R ¹ , R ⁴ , R ⁶ and R ⁸ are each independently a hydrogen atom or a methyl group, and R ⁷ is a bridged cyclic hydrocarbon having a carboxyl group and having 7 to 13 carbon atoms. R ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group.
K, m, and n indicate the composition ratio of each unit, and k + m + n
= 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦ n <1. The weight average molecular weight of the polymer is 2000 to 20.
0000. ) (In the general formula (8), R ¹ , R ⁵ , R ⁶ and R ⁸ are each independently a hydrogen atom or a methyl group, and R ⁷ is a bridged cyclic hydrocarbon having 7 to 13 carbon atoms having a carboxyl group. R ⁹ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms or a hydrocarbon group having 2 to 12 carbon atoms having a hydroxyl group.
K, m, and n indicate the composition ratio of each unit, and k + m + n
= 1, 0 <k ≦ 1, 0 ≦ m <1, 0 ≦ n <1. The weight average molecular weight of the polymer is 2000 to 20.
0000. ) 5. The negative photoresist composition according to claim 1, wherein the crosslinking agent is at least one of the compounds represented by formulas (9) to (12). Embedded image (In the general formula (9), R ¹⁰ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an oxoalkyl group having 3 to 6 carbon atoms, and a ₁ = 1 or 2, a ₂ = 1 or 2, b ₁
= 0 or 1, b ₂ = 0 or 1, a ₁ + b ₁ = 2, a ₂ +
b ₂ = 2. ) (In the general formula (10), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
And R ¹¹ 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. ) (In the general formula (11), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
An alkyl group having 3 to 6 carbon atoms or an oxoalkyl group having 3 to 6 carbon atoms, R ¹¹ is 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, and R ¹² is an oxygen atom. Represents an atom, a sulfur atom, an alkylene group having 1 to 3 carbon atoms or a hydroxymethylene group. ) (In the general formula (12), R ¹⁰ is a hydrogen atom and has 1 carbon atom.
To 6 or an oxoalkyl group having 3 to 6 carbon atoms, and R ¹³ represents a hydrogen atom or a methyl group. ) 6. The negative photoresist composition according to claim 1, wherein the crosslinking agent is a compound represented by the formula (13). Embedded image 7. A photoacid generator comprising a sulfonium salt compound represented by the general formula (14), an iodonium salt compound represented by the general formula (16), an imide compound represented by the general formula (17), and The negative photoresist composition according to any one of claims 1 to 6, which is at least one kind of a diazo compound represented by the formula (18). Embedded image [In the general formula (14), R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently an alkyl-substituted, halogen-substituted or unsubstituted aromatic group, alicyclic group, bridged cyclic hydrocarbon group, 2-oxo alicyclic group Alternatively, it represents an alkyl group, and Y ⁻ is BF ₄ ⁻ , As
F ₆ ⁻ , SbF ₆ ⁻ or formula (15): Z—SO ₃ ⁻ (in the general formula (15), Z is C _n F _{2n + 1} (n is an integer of 1 to 6), an alkyl group or alkyl-substituted or halogenated Represents a substituted or unsubstituted aromatic group). ] (In the general formula (16), R ¹⁷ and R ¹⁸ are each independently an alkyl-substituted or halogen-substituted or unsubstituted aromatic group, alicyclic group, bridged cyclic hydrocarbon group, 2-oxo alicyclic group or alkyl group. BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻
Alternatively, it represents a counter ion represented by the above formula (15). ) (In the general formula (17), R ¹⁹ is a halogen-substituted or unsubstituted alkylene group, an alkyl-substituted or halogen-substituted or unsubstituted divalent aromatic group, R ¹⁶ is a halogen-substituted or unsubstituted alkyl group, an alkyl group or It represents a halogen-substituted or unsubstituted aromatic group.) (In the general formula (18), R ²¹ and R ²² each independently represent an alkyl group, an alkyl-substituted or halogen-substituted or unsubstituted aromatic group, an alkyl group, an alicyclic hydrocarbon group or a bridged cyclic hydrocarbon group. Represents.) 8. A polymer of 50 to 98 parts by weight and a crosslinking agent of 1 to 50 parts by weight.
The negative photoresist composition according to any one of claims 1 to 7, further comprising 0.2 to 15 parts by weight of a photoacid generator that generates an acid upon exposure to light. 9. A step of forming a layer containing the negative photoresist composition according to claim 1 on a substrate to be processed, and forming the layer with a desired pattern with light having a wavelength of 180 to 220 nm. A resist pattern forming method, comprising the steps of: exposing according to the above, baking, and developing to remove a non-exposed portion from the substrate to be processed. 10. The method according to claim 9, wherein the light having a wavelength of 180 nm to 220 nm is ArF excimer laser light.