JPS61143746A - Novel high-energy ray sensitive material - Google Patents

Abstract

PURPOSE:To obtain a resist material superior in sensitivity and resolution and high in dry etching resistance by using a specified copolymer. CONSTITUTION:The resist material is enhanced in sensitivity by using the copolymer having the repeating units each having high energy sensitive group, such as vinyl or epoxy group, and at the same time, a phenyl structure represented by formula I, and also enhanced in dry etching resistance by incorporating the repeating units of formula II, each having a hetero ring in said copolymer. In formulae I and II, R is vinyl, epoxy, or the like; R1 is H, 1-6C alkyl, or halogen, and R, R1 substitute one of the o, m, and p-positions; each of W, X, Y, and Z is H, halogen, cyano, 1-6C alkyl, haloalkyl, or 6-30C substd. by 1-6C alkyl or haloalkyl, -COOR2, -COR2, or the like, nitro, or hetero ring substd. by H, OH, COOH, halogen, nitro, or the like; and R2 is 6-30C aryl or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resist material with high dry etching resistance that is sensitive to high energy radiation. More specifically, the present invention relates to a novel resist material for creating electronic circuits such as semiconductor devices and integrated circuits.

[Conventional technology]

Traditionally, materials that are sensitive to high-energy radiation.

It has been widely used in printing plates, UV inks, photocurable paints, etc., but in recent years, remarkable progress has been made in the field of resist materials for forming fine patterns. Among these, especially integrated circuits (
With the increasing density of IC) and large-scale integrated circuits (LSI),
There is a need for materials that can form finer patterns.

Resist materials are classified into positive resists, which are destroyed by irradiation with high-energy rays and removed by development, and negative resists, which are insolubilized due to crosslinking and other factors due to irradiation, and the unirradiated parts are removed by development. Ru.

To form a circuit such as an LSI, a resist is first applied to a substrate, then a pattern is formed by irradiation with high-energy radiation and development, and then the substrate is etched to create the image. In the manufacturing process, there is a strong trend toward dry etching, and resist materials are strongly desired to have dry etching resistance. That is, resist materials are required to have high sensitivity, high resolution, high dry etching resistance, as well as properties such as heat resistance and adhesion.

The development of resist materials is currently being actively pursued, and materials with various structures have been proposed, and materials having an epoxy group as a high-energy ray-sensitive group are known. for example,
Polyglycidyl methacrylate, epoxidized polyisoprene, epoxidized polybutadiene, etc. have extremely high sensitivity as negative electron beam resists, as reported by J.
El Bartelt (J, L, Bartelt)
, E.D. Feit (II!, D, Fe1t)
) both published the Journal of the Electrochemical Society (J.

urnal of electrochemical
Glycidyl methacrylate/ethyl acrylate copolymer and glycidyl methacrylate are already commercially available, but although they have high sensitivity, they lack resolution and dry etching resistance. There is a side. As products with improved dry etching resistance, epoxidized diallyl orthophthalic acid polymer is disclosed in JP-A-56-64336), diallyl-orthophthalic acid polymer (JP-A-56-7054)
7), a polymer with a naphthyl group introduced into the side chain (Japanese Unexamined Patent Publication No. 192947/1982), etc.
It is presumed that the dry etching resistance is due to the presence of aromatic rings in the side chains, but the dry etching resistance cannot be said to be sufficient.

[Problem that the invention seeks to solve]

As a result of intensive studies based on these technological trends, the present inventors have discovered a new resist material that has higher sensitivity, higher resolution, and especially extremely high dry etching resistance than conventional resist materials. Ta.

[Means for solving problems]

The present invention relates to a high-energy ray-sensitive resist material containing a copolymer (hereinafter referred to as copolymer (A)) consisting of repeating structural units represented by the following structural formulas (1) and (2). .

[However, in formula (1), R represents a vinyl group, an epoxy group, or an episulfide group, and R1 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or a halogen. Also, R7
and R is substituted at the ortho, meta or bara position relative to the carbon atom in the main chain. (2) In the formula, w, x, y and Z are each hydrogen, halogen, cyano group, alkyl group having 1 to 6 carbon atoms, halogenated alkyl group having 1 to 6 carbon atoms, alkyl having 1 to 6 carbon atoms. 6 to 30 carbon atoms substituted with a group or a halogenated alkyl group
an aryl group having 6 to 30 carbon atoms, -C
OOR2, = COR2, -0-COR (R2 is an alkyl group having 1 to 12 carbon atoms or a halogenated alkyl group, an alkyl group having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group) aryl group or aryl group having 6 to 30 carbon atoms), nitro group, or R3 (R3 is hydrogen, hydroxyl group, carboxyl group, halogen, nitro group, amino group, nitrile group, alkyl group having 1 to 6 carbon atoms, or represents a substituent containing a heterocycle substituted with a halogenated alkyl group or a C6-C30 aryl group). However, at least one of w, x, y and Z is a substituent containing a heterocycle. [The copolymer (A) of the present invention has a vinyl group, epoxy group, or thiiranyl group as a high-energy ray-sensitive group in the repeating structural unit represented by structural formula (1), and also has a phenyl skeleton at the same time. Because of this, it has unprecedented sensitivity as a resist material, and because it contains a heterocycle in the repeating structural unit represented by structural formula (2), it has high dry etching resistance.

In formula (1), hydrogen, an alkyl group having 1 to 6 carbon atoms, or halogen can be used for R1, but hydrogen is preferable from the viewpoint of dry etching resistance.

In formula (1), R is a vinyl group, an epoxy group or a thiiranyl group. In making these selections, the reactivity of each functional group and the energy characteristics of the high-energy radiation should be considered. That is, when electron beams or X-rays are used as high-energy rays, vinyl groups or epoxy groups are generally used, and when ultraviolet rays or deep ultraviolet rays are used, epoxy groups or thiiranyl groups are generally used.

The repeating structural unit represented by structural formula (11) does not need to be of one type; by using two or more types in an appropriate ratio, it is possible to create a resist material with a more comprehensive performance that combines the characteristics of each type. can be made.

In formula (1), R can be at any of the ortho, meta, or para positions with respect to the carbon atom in the main chain, but from the viewpoint of sensitivity, the meta or para positions are preferred.

The number average molecular weight of the copolymer (A) is 500 to 1.0.
00,000 is common, and in terms of sensitivity and resolution, it is 3°0.
00 to soo or ooo is preferable.

There is no limit to the molar fraction of the repeating structural unit represented by the structural formula (1) in the copolymer (A), and the molar fraction of the structural formula (1) is generally 1% or more, and from the viewpoint of sensitivity. , 5% or more is preferable, and considering resolution and dry etching resistance, 5% or more is preferable.
% to 90% is more preferred.

W, X in the repeating structural unit represented by structural formula (2)
, Y and Z include hydrogen, halogen, cyano group, and 1 carbon number.
an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group, and an aryl group having 6 to 30 carbon atoms; basis,
-COOR2, to -CO, -0-G O1% (Rz is an alkyl group having 1 to 12 carbon atoms or a halogenated alkyl group, or an alkyl group having 6 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group) to 30 aryl group, or C6 to C30 aryl group), nitro group, or R3 (R3 is hydrogen, hydroxyl group, carboxy/L[, halogen, nitro group, amino group, nitrile group,
A substituent containing a heterocycle substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group, or an aryl group having 6 to 3 o carbon atoms can be used.

In addition, it is essential that at least one of W End of number 6 to 30-
It is preferable to contain a C6 to C30 group at the same time in order to further improve the dry etching resistance. Considering both the ease of availability and the dry etching resistance, The aryl group of 14 is particularly preferred. As a specific example, -C, H,, -C,, H,
, -C14I (9, etc.).

Also, halogen, cyano group, -COOR2, -c.

R7, -C-0-R, (represents an alkyl group having 1 to 12 carbon atoms or a halogenated alkyl group, an aryl having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group) or C6 to C30 group), the l of the film
l1if Impact resistance is improved and at the same time adhesion to the substrate is improved. Therefore, when adhesion to the substrate is particularly required, it is preferable to introduce these substituents.

Further, it is preferable that at least one of W X Y and Z contains a heterocycle from the viewpoint of dry etching resistance of the copolymer (A).

Although various substituents containing a heterocycle can be used, from the viewpoint of dry etching resistance, a substituent containing a nitrogen-containing heterocycle is preferable. ) can be mentioned.

(11(z) (3) (4) [However, in each structural formula, n represents 0 or l, R3 is hydrogen,
It represents a hydroxyl group, a carboxyl group, a halogen, a nitro group, an amino group, a nitrile group, or an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group. ) Among them, structural formulas (3), (5), (16), (17),
(18), (19), (20), (21), (22),
(24) and (25) are preferred, and from the viewpoint of stability as a material, (3), (9), α01. (18), (
21) and (22) are more preferred.

A specific preferred combination of the repeating structural units represented by the structural formula (2) is (W, X.

Y, Z'), (H, H, H, 1le
L), (H,H,CH,Het), (CH,H,H
, Het ), (H, H, CH, Bet )-(CH,
H,H,l1et), (H,H,CH,Bet)
, (CH,H,,H,Het), etc. [However, in the combination formula, Het is structural formula (3), (9), αl,
(18), (21) and (22) are represented. ] Structural formula (2
) It is not necessary to use only one type of monomer, but by using two or more types in an appropriate ratio, or by using a third component, the overall performance as a resist material can be improved. I can do it.

A resist solution is prepared by dissolving the copolymer (A) in a coating liquid, for example, a solvent such as benzene, toluene, tetrahydrofuran, or cellosolve acetate. Next, Konoshi・
The cyst solution is uniformly applied on the substrate, and the temperature is 40 to 1.
Dry at a temperature of 80°C.

Next, a pattern is drawn by irradiating with high-energy rays such as X-rays, electron beams, γ-rays, or far ultraviolet rays, and then developed with an appropriate solvent to form a pattern.

In order to cause a crosslinking reaction by irradiation with ultraviolet rays, it is preferable to add a photodegradable radical initiator. Examples of this initiator include benzophenone, bis(dimethylamino)
Substituted benzophenones such as benzophenone, bis(diethylamino)benzophenone, chlorobenzophenone, dichlorobenzophenone, benzoin alkyl ethers such as benzoin methyl ether and benzoin propyl ether, penzyl dialkyl ketols such as benzyl dimethyl ketal, benzyl ethyl ketal, benzyl, α-
Hydroxyacetophenone 1,2.2'-jethoxyacetophenone, α-hydroxyisobutyrophenone, p
Substituted acetophenones such as -t-butyltrichloroacetophenone, substituted anthraquinones such as 1-chloroanthraquinone and 2-ethylanthraquinone, substituted thioxanthone such as 2-chlorothioxanthone, diisopropylthioxanthone, and 2-methylthioxanthone, phenylglyoxylate, dibenzosbarone , Anthrone, etc. It is also preferable to use a sensitizer suitable for each initiator.

〔Example〕

Specific embodiments will be shown below with reference to Examples, but the present invention is not limited thereto.

The analytical apparatuses and analytical methods used in the following Synthesis Examples, Examples, and Reference Examples are as follows.

GPC (gel permeation chromatography) manufactured by Nihon Bunko, pump: TWINCLU, column:
Measurement of number average molecular weight using A-803, A-804 series and standard polystyrene calibration curve.

Infrared absorption spectrum: Hitachi 285 type infrared spectrometer, KB
Measured by rBr method or NUJOL method.

NMR (Nuclear Magnetic Resonance Spectrum): JεOL, JMR
- Measured value by GX400 type FT-NMR (400MHz).

Synthesis Example 14 - Vinylstyrene oxide synthesis stirrer,
17 with a thermometer! In a reactor, p-divinylbenzene (25g) and sodium hydrogen carbonate (40g) were added.
) Toluene (400 ml) was added, the internal temperature was maintained at 5°C, and a toluene solution of metachloroperbenzoic acid (100 g, 40% by weight) was added dropwise with stirring, and the internal temperature was reduced to 5°C.
Stirring was continued for 10 hours while maintaining the temperature. After the reaction is complete,
The reaction solution was washed with an aqueous sodium hydrogen carbonate solution and dried over anhydrous magnesium sulfate. After removing the desiccant by filtration, toluene was distilled off under reduced pressure, followed by distillation purification to obtain 4-vinylstyrene oxide (I Torr, 74°C). Yield is 6
It was 5g.

Synthesis Example 2 Methanol (300 ml) was added to 11 flasks equipped with a stirrer and a thermometer, 4-vinylstyrene oxide (100 g) was added, and the internal temperature was adjusted to 5°C to 10°C.
Thiourea (35 g) was gradually added while maintaining the
Stirring was continued for 72 hours. After the reaction was completed, methanol was concentrated and distilled off, and the residue was washed with water to obtain 4-vinylstyrene episulfide (60 g). From the proton nuclear magnetic resonance spectrum of the product, the δ value is 7°2-7.5.6.65
．． 5.76.5.20.3.95-4.15.2.8-
3.0, 4.1.1, 1, and 2 protons were observed, respectively.

Synthesis Example 3-1 A 21 flask equipped with a stirrer, a dropping funnel, and a temperature needle was purged with nitrogen, and dried tetrahydrofuran (500 ml
) and diisopropylamine (200g), and heated to 0°C.
Cooled to . Next, a 15% by weight n-butyllithium hexane solution (190 ml) was added dropwise with stirring. 9-vinylcarbazole (80 g) while maintaining the temperature at 0°C.
), and a solution of p-divinylbenzene (50 g) in tetrahydrofuran (200 ml) was added continuously at a rate of 30 ml/hr, and stirring was continued for an additional 8 hours under a nitrogen stream. After adding methanol (30 ml), the reaction mixture was slowly added to a large amount of methanol, resulting in a white precipitate. This was filtered, washed with water, and dried to obtain a white solid (65.0 g). This white solid was easily soluble in acetone, ethyl acetate, toluene, chloroform, etc. The number average molecular weight determined by GPC is 48,00
It was 0.

The NMR spectrum has a δ value of 1.5 around 0.8 to 3.0.
Broad absorption peaked at 5.0-5.3 and 5.5
~5.8 slightly sharp absorption, 6.0~7.6, 6.6
Broad absorptions with peaks of 7.1 and 7.1 were observed.

From the relative intensities of the above absorptions, the molar ratio of divinylbenzene and carbazole was determined to be 5:4.

Synthesis Example 3-2 Into a 100ml reactor equipped with a temperature needle and a stirrer, the compound obtained above (2.6g) and methylene chloride (30ml
l), add sodium hydrogen carbonate (2.6 g), and add 5
Cooled to ℃. A solution of metachloroperbenzoic acid (3.6 g) in methylene chloride (24 ml) was added dropwise with stirring, and the reaction solution was kept at 5° C. and stirred for 24 hours.

After confirming with iodized starch paper that metachloroperbenzoic acid had disappeared from the reaction solution, the reaction solution was washed three times with a saturated aqueous sodium bicarbonate solution and dried over anhydrous magnesium sulfate. After filtering off the desiccant, methylene chloride was distilled off under reduced pressure to obtain a white powder (2.6 g). This was easily soluble in organic solvents such as toluene, methyl ethyl ketone, ethyl acetate, and chloroform. The number average molecular weight determined by GPC was 52,000. The NMR spectrum shows a broad absorption with a peak of 1.5 near the δ value of 0.8 to 3.0, a slightly broad absorption of 2.8, 3, 1, 3, 8, 5.2, and a slightly broad absorption at 5°7. Absorption was observed in a wide range from 6.0 to 7.0, with peaks at 6.6 and 7°1.

Synthesis Example 4 17! Equipped with a stirrer and a temperature needle! Methanol/toluene (300/300ml V/V) was added to a flask, and the epoxy compound obtained in Synthesis Example 3 (100g
), and while maintaining the internal temperature at 5℃ to 10"C,
Thiourea (50 g) was added gradually and stirring continued for 72 hours. After the reaction was completed, methanol was concentrated and distilled off, and the residue was washed with water to obtain an episulfide compound (72.3 g).

Synthesis Example 5 1! Equipped with a stirrer, temperature needle, and reflux condenser! Purified toluene (400 ml) was added to a separable flask, and the epoxy compound (50 g) obtained in Synthesis Example 1 was added.
and 1-vinylindole (50 g) were added with stirring, and α,α゛-azobisisobutyronitrile (1.0 g) was added.
was added, and while maintaining the internal temperature at 70°C, it was heated under a nitrogen stream for 7 days.
Stirring was continued for an hour. After the reaction was completed, the reaction mixture was poured into a large amount of methanol and left overnight. A white precipitate was separated by filtration, washed with methanol, and then dried under reduced pressure at room temperature to obtain a copolymer. The yield was 87 g, and the number average molecular weight was 23,000 according to GPC.

Furthermore, the NMR spectrum of the copolymer revealed that it contained 56 mol% of an epoxy compound.

Synthesis Example 6 Purified toluene (400 ml) was added to 11 separable flasks equipped with a stirrer, temperature needle, and reflux condenser, and the episulfide compound (50 ml) obtained in Synthesis Example 2 was added.
g) and 1-vinylpyrrole (50 g) were added under stirring, and α,α”-azobisisobutyronitrile (1,0
g) was added, and stirring was continued for 7 hours under a nitrogen stream while maintaining the internal temperature at 70"C. After the reaction was completed, the reaction mixture was poured into a large amount of methanol and left overnight. The white precipitate was filtered. The mixture was separated, washed with methanol, and then dried under reduced pressure at room temperature to obtain a copolymer.

The yield was 87g, and from cpc, its number average molecular weight was 12
．． It was 000.

Further, the NMR spectrum of the copolymer revealed that it contained 78 mol% of an epoxy compound.

Synthesis Example 7 In Synthesis Example 3, instead of 9-vinylcarbazole, 1
A white copolymer (5.1 g) was obtained in exactly the same manner except that -vinylimidazole was used. The number average molecular weight determined by GPC was 9,800, and NMR revealed that it contained 64 mol% of divinylbenzene.

Synthesis Example 8 In Synthesis Example 5, 1-vinylindole was replaced with 1-
The same procedure was carried out except that phenyl-2-(9-vinylcarbazole Σethylene was used, and 48 g of a white copolymer was obtained. The number average molecular weight determined by CPC was 62.000.
It was found from the NMR spectrum that it contained 52 mol% of epoxy compound.

Synthesis Example 9 A white copolymer (42 g) was obtained in exactly the same manner as in Synthesis Example 3 except that 1-naphthyl-2-(9-vinylcarbazole)-ethylene was used. The number average molecular weight determined by GPC was 89.000, and the NMR spectrum revealed that 72 mol% of divinylbenzene was contained.

Synthesis Example 10 A white copolymer (32 g) was obtained in exactly the same manner as in Synthesis Example 6 except that 1-phenyl-L (9-vinylcarbazole)-ethylene was used. The number average molecular weight determined by GPC was 32.000, and the NMR spectrum revealed that it contained 84 mol% of an episulfide compound.

Examples Various copolymers obtained in Synthesis Examples 3 to 10 were dissolved in the coating solutions shown in Table 1 to prepare a resist coating solution and spin-coated onto a silicon wafer to form a resist layer (thickness: 1 μm).
was formed. Next, pre-beta was performed under the conditions shown in Table 1, and a pattern was drawn using an electron beam drawing device (acceleration voltage: 20 KV). After irradiation, it was processed with a prescribed developer.

In addition, the dry etching resistance was evaluated using a parallel plate type etching apparatus and using CF4/02 (CF4/02) as the etchant gas.
95/5% by volume) I Torr 0.3W with mixed gas
Etching was performed for 5 minutes under the conditions of /di, and the decrease in the thickness of the resist film was measured. The results are shown in Table 1.

Table 1

Claims (2)

[Claims] (1) A high-energy ray-sensitive resist material containing a copolymer consisting of repeating structural units represented by the following structural formulas (1) and (2). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(2) [However, in formula (1), R represents a vinyl group, epoxy group, or episulfide group, and R_1 Represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or halogen. Also, R
_1 and R are ortho, meta,
Alternatively, substitute at any of the para positions. (2) In the formula, W, X, Y and Z each represent hydrogen, halogen, cyano group, alkyl group having 1 to 6 carbon atoms, or 1 carbon number.
a halogenated alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 30 carbon atoms, -COOR_2, -COR_2,
-O-COR_2 (R_2 is an alkyl group having 1 to 12 carbon atoms or a halogenated alkyl group, an aryl group having 6 to 30 carbon atoms substituted with an alkyl group having 1 to 6 carbon atoms or a halogenated alkyl group, or an aryl group having 6 to 30 carbon atoms) 6 to 30 aryl group), nitro group, or R_3(R
_3 is hydrogen, hydroxyl group, carboxyl group, halogen, nitro group, amino group, nitrile group, alkyl group having 1 to 6 carbon atoms or halogenated alkyl group, or 6 carbon atoms
represents a substituent containing a heterocycle substituted with 1 to 30 aryl groups). However, at least one of W, X, Y and Z is a substituent containing a heterocycle. ]