JPS61285450A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive compsn. which has excellent sensitivity, resolution, etc. and is suitable for production of integrated circuit elements by constituting the compsn. of the sulfonate of a specific arom. azidosulfonic acid and compd. having a phenolic hydroxyl group and arom. polymer having an OH group. CONSTITUTION:The photosensitive compsn. consisting of the azide compd. expressed by the formula (Ar is an arom. ring of benzene, naphthalene, anthracene and phenanthrene which have no nucleus substituents except N3 group and SO2 group or may contain halogen or NO2 as the nucleus substituent, Ar' is an arom. compd. having >=1 phenolic OH and the residual arom. group except >=1 phenolic OH group remaining therein, n is >=1), novolak type phenolic resin and the polymer selected from the group consisting of a polyhydroxystyrene polymer and polyvinyl hydroxy naphthalene polymer is prepd. The compsn. for a negative type photoresist having excellent dimensional accuracy, adhesiveness to a substrate, heat resistance, chemical resistance, etc. is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photosensitive composition, and more particularly to a negative photosensitive composition for pattern formation used in the manufacture of semiconductor integrated circuit devices.

Therefore, the present invention can be utilized in the industrial field of manufacturing materials for semiconductor integrated circuit elements.

2. Description of the Related Art Semiconductor devices such as transistors, integrated circuits (abbreviated as IC), and large-scale integrated circuits (abbreviated as LSI) have been manufactured by microfabrication technology using photolithography or photoetching. This method involves coating a photoresist layer on a silicon wafer, overlaying a mask with a predetermined pattern on it, and exposing it to light.
After developing to form an image, etching is performed to form a desired pattern, and this is used to perform selective diffusion. Usually, this process is repeated several times to perform selective diffusion, and then the aluminum electrode is installed.
Then, a semiconductor electronic component is created by performing wiring processing.

There are two types of photoresists commonly used in the semiconductor industry: negative type, which undergoes a crosslinking reaction upon irradiation with electromagnetic waves or active light such as particle beams, and positive type, which decomposes and becomes solubilized. After selectively irradiating the photoresist with active light (that is, so as to form an image), the photoresist is brought into contact with an organic solvent or alkaline aqueous solution called a developer.
In the conventional negative photoresist, the non-irradiated areas are selectively dissolved and removed by a developer, and in the case of positive photoresists, the irradiated areas are selectively dissolved and removed by the developer to obtain a desired pattern.

Typical negative photoresists are mainly composed of cyclized rubber and aromatic bisazide, but the limit of resolution of patterns obtained from them is said to be 1.5 gm even for line and space, and recently In the age of ultra-LSI, various improvements and developments are being made to meet the technical demands. , 1-azidopyrene, 1,8-diazidnaphthalene, and a mixture with an azide compound such as 2,6-di(4'-7zidobenzal)-4-methylcyclohexanone is described in JP-A-58-111940. Novolak resin or polyhydroxystyrene resin and p-azidoben, chromic acid 2-
Hydroxyethyl, metaazidobenzoic acid 2-(N,N-
Mixtures with aromatic azide compounds such as dimethylamino)ethyl are disclosed.

Problems to be Solved by the Invention The requirements for photoresists used in the manufacture of semiconductor integrated circuit devices are generally (1) high resolution and good dimensional accuracy, and (2) high sensitivity and resistance to changes in exposure dose. There should be little dimensional change.

(3) Good adhesion to the substrate and excellent chemical resistance; (4) No striations or pinholes; (5) Excellent dry etching resistance and heat resistance. 6) It is stable in quality and does not change over time, and there is no variation between lofts; (7) it does not contain impurities that adversely affect device characteristics; (8) it has wide tolerance in the phosphorography process; (9) ) It is extremely difficult to provide materials that satisfy all of these requirements, such as low price and easy availability.

Therefore, an object of the present invention is to provide a novel negative photoresist that is highly sensitive and has excellent resolution.

Means for Solving the Problems In view of the above circumstances, the present inventors have conducted intensive research and have developed a compound in which an azide group and a sulfonyl group are directly bonded to an aromatic ring such as a benzene ring, naphthalene ring, or anthracene ring. is photosensitive and has a high affinity with polymers in which a hydroxyl group is directly bonded to an aromatic ring, such as novolak-type phenolic resins and polyhydroxystyrene; therefore, it is difficult to mix such azide compounds with polymers. The photoresist obtained by this method has good compatibility, and has high sensitivity because the azide compound and polymer are uniform.Moreover, since the polymer and the azide compound each have at least one aromatic ring, there is little swelling by organic solvents, and it has high resolution. The present invention was completed based on this discovery.

The gist of the present invention is the general formula % (1) [wherein Ar has no nuclear substituent other than an azide group and a sulfonyl group, or has a nuclear substituted halogen atom or nitro group] Good benzene ring.

It is an aromatic ring such as a naphthalene ring, an anthracene ring, or a phenanthrene ring, and Ar' is an aromatic compound having at least one phenolic hydroxyl group. It is an aromatic residue excluding at least one of its phenolic hydroxyl groups, and n is an integer of 1 or more. ] This is a photosensitive composition characterized by comprising an azide compound represented by the following and a polymer.

The configuration of the present invention will be explained in detail below.

(Azide compound) The azide compound in the photosensitive composition of the present invention has an azide group and no other nuclear substituent, or a benzene ring which may have a nuclear substituted halogen atom or a nitro group. , a sulfone of an aromatic sulfonic acid having a naphthalene ring or anthracene ring (hereinafter simply referred to as an azido group-containing aromatic sulfonic acid) and an aromatic compound having at least one phenolic hydroxyl group (hereinafter simply referred to as a phenol compound) It is an acid ester. Specific examples of the azido group-containing aromatic sulfonic acid constituting the ester include the following.

4-azidobenzenesulfonic acid, l-azido-2-naphthalenesulfonic acid, l-azido-
4-Naphthalenesulfonic acid.

l-azido-5-naphthalenesulfonic acid, 1-azido-
6-naphthalenesulfonic acid, l-azido-7-naphthalenesulfonic acid.

1-azido-8-naphthalenesulfonic acid, ? -azido-1-naphthalenesulfonic acid, 2-azido-5-naphthalenesulfonic acid.

2-azido-6-naphthalenesulfonic acid, 2-azido-
7-Naphthalenesulfonic acid.

2-azido-8-naphthalenesulfonic acid.

l-azido-4-nido-o-5-naphthalenesulfonic acid, l-azido-4-chloro-6-naphthalenesulfonic acid, 2-azido-4-nitro-6-naphthalenesulfonic acid, 2-azido-4-chloro-6-naphthalenesulfonic acid, l-azido-8-nitro-5-naphthalenesulfonic acid, 1-azido-8-chloro-5-naphthalenesulfonic acid, 2-azido-8-nitro-4-naphthalenesulfonic acid, 2-azido-8-chloro-4-naphthalenesulfonic acid, l-azido-8-nitro-4-naphthalenesulfonic acid, l-azido-8-chloro-4-naphthalenesulfonic acid, l-azido-4-anthracene sulfonic acid.

2-azido-4-anthracenesulfonic acid, ■-azido-5-anthracenesulfonic acid, 2-azido-5-anthracenesulfonic acid.

Moreover, the following can be illustrated as a phenol compound.

gallic acid alkyl esters, such as n-propyl gallate and isoamyl gallate, 2.3.4-
Trihydroxybenzophenone, 2.4.6-) benzophenone substitutes such as 2.2', 4.4'-tetrahydroxybenzophenone, 2.4.6-)-tetrahydroxybenzophenone, bisphenol A, 2-naphthyl°-2.3.4 - Naphthylphenyl ketone substitutes such as 1-lyhydroxyphenyl ketone.

2-naphthyl-2-phenylpropane substitutes, such as 2-(α-naphthyl)-2-(2',4'-dihydroxyphenyl)propane.

The azide compound in the present invention can be obtained by sulfonic acid esterification of the azide group-containing aromatic sulfonic acid and the phenol compound by a conventional method.

(Polymer) The polymer in the composition of the present invention is a solvent-soluble polymer compound having a phenolic hydroxyl group, and specific examples include primary polymers.

novolac type phenolic resin, polyhydroxystyrene polymer, Polyvinylhydroxynaphthalene polymer.

These polymers can be used alone or in combination.

(Blending ratio) The photosensitive composition of the present invention contains 0.5 to 30% by weight, preferably 5 to 30% by weight, of the azide compound based on the polymer.
It is made by blending 20% by weight.

If the content of the azide compound is too low, the sensitivity will be low and only weak images will be obtained, which is undesirable. This is not preferable because an azide compound will precipitate on the film surface, making it impossible to form an accurate fine pattern.

(Pattern Formation Method) In order to form a fine pattern using the photosensitive composition of the present invention, this photosensitive composition is dissolved in a solvent to form a film forming coating solution, and this is applied to a substrate such as a silicon wafer. Apply on top.

Examples of solvents that can be used as the above solvent are as follows.

Cyclohexanone.

Methyl n-butyl ketone.

Methyl n-propyl ketone, ethyl n-butyl ketone, ethylene glycol monomethyl ether acetate-ethylene glycol monoethyl ether acetate, ethylene glycol motsuptyl ether.

Ethylene glycol monoethyl ether.

toluene, xylene, l-Nitropropane.

2-nitropropane, 1.1,2.2-tetrachloroethane, N,N-dimethylformamide, etc.

Although the above-mentioned solvents may be used alone, the preferred solvent is a mixture of multiple types of solvents.

When the substrate provided with the photosensitive layer is imagewise irradiated with actinic light such as ultraviolet rays, far ultraviolet rays, The image is formed by removing the unexposed portions through development processing.

Note that as the developer, the solvent used in the film-forming coating solution can be used as is, but the developer is not limited thereto.

EXAMPLES The present invention will be explained in detail with reference to synthesis examples and examples below, but the following synthesis examples and examples are for illustrating the present invention and are not intended to limit the present invention.

Synthesis Example 1 After dissolving 5 g of α-naphthylamine-5-sulfonic acid in a 6% aqueous sodium carbonate solution, it was acidified with a 3% aqueous hydrochloric acid solution, cooled to 0 to 5°C using a cryogen, and dissolved while stirring. After adding 1.2 g of sodium nitrite and reacting for 15 minutes.

A 20% aqueous solution of 2.5 g of sodium azide is added to the resulting diazonium salt aqueous solution while stirring. Further 0~
The mixture is kept at 5°C and reacted for 1 hour.

Then, the desired azide compound precipitates out. The precipitate was then suction filtered, purified by recrystallization using activated carbon and distilled water, and the obtained crystals were chlorinated with thionyl chloride to obtain 2 g of α-azidonaphthalene-5-sulfonyl chloride.

2 g of the obtained α-azidonaphthalene-5-sulfonyl chloride and 0.5 g of isoamyl gallate were dissolved in dioxane, filtered, and then 0.2 g of sodium carbonate was added as a catalyst.
Add a 10% aqueous solution of and react at room temperature for 2 hours. Pour the reaction solution into 5 times the amount of pure water to precipitate crystals, filter the crystals, recrystallize with ethanol, and air dry. 3°4.5-tri(azidonaphthalene-5-sulfonyl) gallic acid isoamyl ester is obtained. The obtained azide compound has an infrared absorption spectrum of 2140
cm, 1390cm, and 1200cm
cm", and in the ultraviolet/visible absorption spectrum, the absorption maximum was 335 nm.
By R spectroscopy, thin layer chromatography and elemental analysis,
Confirmed to be pure.

Synthesis Example 2 1.6 m of chlorosulfonic acid in 40 mfl of chloroform
Add M, cool to 0°C with a cryogen, and add 2 g of α-acetylaminoanthracene while stirring. After 15 minutes, the temperature was returned to room temperature, and the reaction took a total of 1.5 hours. The lower oily substance was separated from the upper layer, washed twice with chloroform, and then the reaction product, a compound in which sulfonyl chloride was introduced into α-7cetylaminoanthracene, was washed with pure water for 40 minutes.
Oil is poured into m1 to decompose it and dissolve it as sulfonic acid. Furthermore, 4 mJL of hydrochloric acid was added, boiled for 15 minutes to hydrolyze the acetylamino group, and cooled on ice to precipitate crystals.
Filter by suction to obtain crystalline α-7minoanthracene-4-sulfonic acid. Obtained α-aminoanthracene-4
-Sulfonic acid was azidated and chlorosulfonylated in the same manner as in Synthesis Example 1, and 1.5 g of α-azidoanthracene-4-sulfonyl chloride thus obtained was dissolved in dioxane together with 0.6 g of inamyl gallate, and sodium carbonate was dissolved in dioxane. The reaction was carried out in the same manner as in Synthesis Example 1 using 2.5 mJL of a 5% aqueous solution of as a catalyst to obtain 1.8 g of 3,4°5-tri(azidoanthracene-4-sulfonyl) gallic acid inamyl ester. The infrared absorption spectrum of the obtained azide compound shows absorption maxima at 2110 cm, 1-390 cm, and 1200 Qm-1, and the ultraviolet/visible absorption spectrum shows absorption maxima at 405 nm, 390 nm, and 380 nm.
There was an absorption maximum at nm.

Synthesis Example 3 34.2 g of 4-azido-3-nitrobenzenesulfonyl chloride obtained by azidation and chlorosulfonylation in the same manner as in Example 1 using 2-nitroaniline-4-sulfonic acid as jul was 2° Synthesis Example 1 Dissolved in dioxane with 10 g of 4.6-trihydroxyhenzophenone and using 10 m of a 10% aqueous solution of sodium carbonate as a catalyst.
2.4.6-tri(4-azido-3
-nitrobenzenesulfonyl)benzophenone ester was obtained.

Example 1 Nopola 7 resin (PSF-2805 manufactured by Gunei Chemical Co., Ltd.) 10
g, 1 g of 3,4,5-tri(azidnaphthalene-5-sulfonyl) gallic acid isoamyl ester obtained in Synthesis Example 1
ethylene glycol monoethyl ether acetate)2
The solution was dissolved in 2 g, filtered under pressure, and coated on a silicon wafer to a thickness of lpm using a spinner. After pre-baking in a hot air dryer at 90°C, the UV exposure device PLA-520
F (manufactured by Canon), using a cold mirror CM-290 and proximity exposure to deep ultraviolet rays through a resolution test mask with a pattern of minimum line width 0.5 JLm.
Next, it was developed using a mixed developer consisting of isoamyl acetate and xylene, and rinsed with xylene.
A faithful resist pattern was obtained by resolving up to m.

Example 2 3,4.5-)su(azidonaphthalene-) obtained in Synthesis Example 1
Exposure was carried out in exactly the same manner as in Example 1, using 3,4,5-tri(azidoanthracene-4-sulfonyl) gallic acid isoamyl ester obtained in Synthesis Example 2 instead of 5-sulfonyl) gallic acid isoamyl ester. After development, a faithful resist pattern with resolution down to 0.51 Lm was obtained.

Example 3 10 g of polyhydroxystyrene (manufactured by Marukubi Sekiyu Co., Ltd.), 0.5 g of 2,4.6-1s(4-azido-3-nitrobenzenesulfonyl)benzophenone ester obtained in Synthesis Example 3
was dissolved in 32 g of cyclohexanone, exposed and developed in exactly the same manner as in Example 1 to obtain a faithful resist pattern that was also resolved down to 0.5 gm.

Example 4 After forming a photosensitive resin layer on a silicon wafer in the same manner as in Example 1, a scanning electron microscope HMS-21 (
(Hitachi model), exposure amount 10JLC/crn'
The resist pattern was linearly irradiated with an electron beam under the following conditions and developed in exactly the same manner as in Example 1 to obtain a resist pattern that was resolved to 0.5 pm.

Example 5 After forming a photosensitive resin layer on a silicon wafer in the same manner as in Example 1, the X-ray tube AFX-51A-RH was
Using an X-ray generator (manufactured by Toshiba) and an X-ray generator Proximity exposure, Example 1
A resist pattern with resolution down to 0.5 Bm was obtained by developing in exactly the same manner as above.

Example 6 After forming a resist pattern on a silicon wafer provided with S and 02M by the method of Example 1, a plasma etching apparatus OAPM-400 (Tokyo Ohka Kogyo Department) was used, and etching gases were CF and CHF3. :Dry etching was performed for 60 seconds using a mixed gas of 5. s
While 102 DI was etched by 0.24 JLm, the resist film was reduced by only 0.03 pm.

The photosensitive resin used in Storage Stability Test Example 1 was sealed and kept at -15℃ and -3℃.
The samples were left in constant temperature dark rooms at 20°C and 20°C for 6 months.

When a pattern was formed using this photosensitive resin in exactly the same manner as in Example 1, similar results were obtained.

Remaining Film Ratio Test In the operations of Examples 1, 4, and 5, the amount of remaining film after development was measured while changing the exposure amount, and an exposure amount-remaining film ratio curve was obtained. The results are shown in the curves (a
).

For comparison, a photoresist prepared by dissolving 10 g of cyclized rubber and 1 g of 3,4.5-)su(azidonaphthalene-5-sulfonyl) gallic acid isoamyl ester in 22 g of xylene was used, and the film thickness was the same as above with lJLm. The film was irradiated with varying exposure amounts using an exposure device, developed and rinsed under specified conditions, and the amount of residual W2 after development was measured to obtain an exposure amount-residual film rate curve. The results are shown in the curves (b) in Figures 1, 2, and 3.
).

Figure 1 shows exposure to far ultraviolet rays, Figure 2 shows exposure to electron beam,
FIG. 3 shows the results of exposure to X-rays.

Comparing curves (a) and (b) in Figures 1, 2, and 3, it is clear that the photosensitive composition of the present invention is significantly superior to conventional compositions. .

Effects of the Invention The photosensitive composition of the present invention can be
It is highly sensitive to actinic rays such as radiation, and compared to conventional negative photoresists, it is possible to obtain images with high resolution without causing swelling due to the developer during development. Furthermore, when the support to which the photosensitive composition is applied is dry-etched using the composition as a mask, the composition shows resistance and has sufficient practicality, and the azide compound and polymer are soluble in solvents. Since the composition of the present invention has excellent solubility and is stable over a long period of time, it can withstand long-term storage and is extremely useful as a photoresist for semiconductors.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are graphs showing the residual film rate of the photosensitive composition of the present invention and the residual film rate of the conventional photosensitive composition.

Claims (3)

[Claims] (1) General formula (N_3-Ar-SO_2-O)_n-Ar' (1) [
In addition to the azide group and the sulfonyl group, Ar in the formula represents a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, which may have no nuclear substituent or a nuclear substituted halogen atom or a nitro group. is an aromatic ring; Ar' is an aromatic residue from which at least one phenolic hydroxyl group has been removed in an aromatic compound having at least one phenolic hydroxyl group; and n is an integer of 1 or more. ] A photosensitive composition comprising an azide compound represented by the following and a polymer. (2) The aromatic compound having at least one phenolic hydroxyl group is a gallic acid ester, a benzophenone substituted product, bisphenol A, a naphthylphenyl ketone substituted product,
The photosensitive composition according to claim 1, which is at least one compound selected from the group of 2-naphthyl-2-phenylpropane substituted products. (3) Claim 1 or 2, wherein the polymer is at least one polymeric compound selected from the group of novolac-type phenolic resin, polyhydroxystyrene polymer, and polyvinylhydroxynaphthalene polymer. photosensitive composition.