JPS61118744A - Positive photoresist composition - Google Patents

Abstract

PURPOSE:To obtain the titled compensation having a high sensitivity and an excellent heat-resistance property suitable for producing IC, LSI etc. by incorporating naphthoquinone-1,2-diazidosulfonic acid ester of polyhydroxybenzophenone to an alkaline soluble resin. CONSTITUTION:The titled composition is prepared by dissolving a photosensitive component of a compd. shown by the formula wherein D is naphthoquinone-1,2- diazido-5-sulfonyl or naphthoquinone-1,2-diazido-4-sulfonyl group, and the alkaline soluble resin such as a novolak resin to a suitable org. solvent. The obtd. composition is coated on a silicone wafer and dried to form a resist film. The very fine pattern is obtd. by exposing a pattern on the obtd. resist by an ultra-high voltage mercury lamp followed by washing the obtd. resist with an alkaline aqueous solution of (CH3)4NOH. The titled composition has a long storage life in addition to the prescribed characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial application field is a positive photoresist composition, more specifically, it is suitably used as a resist for ultra-fine processing in the manufacture of semiconductor devices such as ICs and LSIs.
The present invention relates to a positive photoresist composition which has high sensitivity and excellent heat resistance, and which does not generate foreign matter after one hour when used as a solution.

Conventional technology Conventionally, IC-? 'In the manufacturing process of semiconductor devices such as LSI, a thin film of a photoresist composition is formed on a silicon wafer as microfabrication using the photoetching method, and a mask pattern with a pattern of the semiconductor device is drawn on it by ultraviolet irradiation. A method is used in which the resist pattern is transferred, developed, and the silicon wafer is etched using the resist pattern thus obtained as a protective film. In this method, in order to obtain a thin film of a uniform thickness of the photoresist composition, the photoresist composition is usually dissolved in an organic solvent, and this solution is applied using a spinner or the like. The organic solvents used in this case include ketones that have good solubility in the composition;
Esters and seronulpes are considered to be optimal, and are limited to those having a boiling point in the range of 125 to 165°C from the viewpoint of uniformity of coating and drying properties.

By the way, as a positive photoresist composition.

Aromatic polyhydroxy compound naphthoquinone-1,2-
It is already known that diazide sulfone ester (hereinafter abbreviated as azido ester) containing as a t-photosensitive component is suitable. However, when a photoresist composition containing this azide ester is dissolved in an organic solvent to form a solution of the photoresist composition, although the azide ester dissolves extremely well in a ketone solvent, it decomposes significantly in the solution. There are many problems with storage stability,
Furthermore, in the case of ester-based solvents and selonulp-based solvents, although the storage stability of the azide ester is good, the solubility is poor and fine crystals often precipitate over the course of one hour. The aromatic polyhydroxy compound residue in the azide ester that can be used for this purpose is phenolic novolak resin.

Cresol novolac resin, gallic acid ester.

It is limited to polyhydroxybenzophenone, etc.
Among these, the aromatic polyhydroxy compound residue in the azide ester for high sensitivity is selected from gallic acid esters and polyhydroxybenzo 7e, which contain a large number of hydroxyl groups in the unit molecule. is normal., f'172.

Many proposals have been made regarding 7-toquinone-1,2-diazide sulfonic acid esters of droxybenzophenones (U.S. Pat. No. 3,046,118, U.S. Pat. No. 3,106,465). Specification.

Specification No. 3,148,983, Japanese Patent Publication No. 37-180
Publication No. 15).

Problems to be Solved by the Invention However, naphthoquinone-1,2-diazide sulfonic acid esters of polyhydroxybenzophenones cannot sufficiently overcome the drawbacks of the conventional photoresist compositions described above. Furthermore, heat resistance is also not sufficient. Also, among the esters, 4.2.3.4-
Trihydroxybenzophenone naphthoquinone-1,2
-Diazide sulfonic acid triester has good compatibility with alkali-soluble resins such as V solvents and novolac resins, and is said to be usable as a photosensitive component of photoresist compositions, but this is not always satisfactory. Until now, positive photoresist compositions used for ultrafine processing in the manufacture of semiconductor devices have sufficiently high sensitivity and excellent heat resistance, and are free from foreign substances when used as a solution. The reality is that no composition has been found that does not cause this.

In view of these circumstances, the purpose of the invention is to create a resist that is highly sensitive and has excellent heat resistance and is suitable for use as a resist for ultra-fine processing, especially in the manufacture of semiconductor devices, and also does not generate foreign matter when used as a solution. An object of the present invention is to provide an excellent positive photoresist composition.

Means for Solving the Problems As a result of intensive research, the inventors found that 2 as a photosensitive component.
, 3.4. It was discovered that the above object could be achieved by using naphthoquinone-1,2-diazide sulfonic acid tetraester of 4'-tetrahydroxybenzophenone, and based on this knowledge, the invention was completed. It's arrived.

That is, 1 the present invention provides an alkali-soluble resin with a general formula (wherein D is 7-toquinone-1,2-diazide-5-sulfonyl group or naphthoquinone-1,2-diazide-4-
The object of the present invention is to provide a positive photoresist composition containing a compound represented by a sulfonyl group.

The compound represented by the general formula (I) used as a photosensitive component in the composition of the present invention is 2.3.4.4'-tetrahydroxybenzophenone naphthoquinone-1,2
-diazide-5-sulfonic acid tetraester or naphthoquinone-1,2-diazide-4-sulfonic acid tetraester 1), these include 1, for example 2°3.4.4'-tetrahydroxybenzophenone and 7toquinone-1. 2-
Diazide-5-sulfonyl chloride or 7-toquinone-1,2-diazide-4-sulfonyl chloride is dissolved in dioxane, and an aqueous solution of alkali carbonate or alkali hydrogen carbonate is added dropwise at room temperature to cause a condensation reaction. A method of neutralizing and purifying the reaction product (U.S. Pat. No. 3,106.465, U.S. Pat. No. 3.148.9)
It can be manufactured by a method similar to the method described in the specification of No. 83).

The content of the compound represented by the general formula (1) in the composition of the present invention is preferably 5 weight range or more in the photosensitive fraction, and if the amount is less than this, the effect will not be fully exhibited.

The composition of the present invention contains the general formula (1) as a photosensitive fraction.
In addition to the compounds represented by, if necessary, 2゜3.4.
The power of 4'-tetrahydroxybenzophenone 7toquinone-1,2-diazide sulfonic acid triester, diester, and monoester, of course.

Other quinonediazide group-containing compounds 1 For example, orthobenzoquinonediazide, parabenzoquinonediazide, orthoquinonediazide, orthoanthraquinonediazide, or nuclear substituted derivatives thereof such as orthoquinonediazide or orthoquinonediazide sulfonic acid esters, as well as orthoquinonediazide sulfonyl chloride and hydroxyl groups or Examples of compounds with amino groups (e.g. phenol, p-methoxyphenol, dimethylphenol, hydroquinone,
Bisphenol A, naphthol, hyrocatechol, pyrogallol.

pyrogallol monomethyl ether, pyrogallol-1,
3-dimethylfur, gallic acid, gallic acid esterified or etherified with some hydroxyl groups left, aniline, p-
A reaction product with aminodiphenylamine or the like can be used in combination with a compatible compound.

In the composition of the present invention, an alkali-soluble resin is used as the film-forming substance. Examples of this alkali-soluble resin include 1, for example, a novolak resin produced from phenol or cresol and aldehydes, polyvinyl alcohol, polyvinyl alkyl ether, a copolymer of styrene and acrylic acid, and a copolymer of methacrylic acid and methacrylic acid alkyl ester. Polymers, hydroxystyrene polymers, polyvinylhydroxybenzoate, polyvinylhydroxybenzal, and the like can be mentioned.

These alkali-soluble resins are usually used in an amount of 1% by weight per 10 parts by weight of the optical component containing the compound represented by the general formula ([)].
It is used in a range of 200 parts by weight, preferably 10 to 60 parts by weight. If the amount of the alkali-soluble resin is too large, the fidelity of the resist image will be poor and the transferability will be poor, and if it is too small, the uniformity of the resist film will be poor and the resolution will also be reduced.

The composition of the present invention is preferably used in the form of a solution by dissolving the above-mentioned photosensitive fraction and alkali-soluble resin in a suitable solvent.

Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone and inamyl ketone; monomethyl ether and monoethyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or hashiethylene glycol heptanoacetate.

Mention may be made of polyhydric alcohols such as monoglobyl ether, monobutyl ether or monophenyl ether and their derivatives, cyclic ethers such as nidioxane, and esters such as methyl acetate, ethyl acetate, butyl acetate. These may be used alone or 2a
One or more may be used in combination.

Among these, polyhydric alcohols and their derivatives, so-called perrosol solvents, are particularly preferably used in photoresist compositions for microfabrication of semiconductor devices.

The composition of the present invention may further contain compatible additives, such as a sensitizer to increase the sensitivity of the photosensitive component, if necessary.
Conventional additives such as additional resins, plasticizers, stabilizers to improve the properties of the resist film, or colorants to make the developed image more visible can be added.

To give one example of a preferred method of using the composition of the present invention, first, a photosensitive component and an alkali-soluble resin such as a phenol novolak resin are placed on a support such as silicone urethane in a suitable solvent as described above. The dissolved solution is applied with a spinner, etc., and dried to fully form a photosensitive #, and then a desired mask pattern is formed using a light source 5 that emits ultraviolet light, such as a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, a xenon lamp, etc. Either the electron beam is exposed to light through the electron beam, or the electron beam is irradiated while scanning. Next, when this is immersed in a developer, for example, a weakly alkaline aqueous solution such as a 1-2 aqueous sodium hydroxide solution, the portions that have been solubilized by exposure are selectively dissolved and removed, resulting in an image faithful to the mask pattern. I can do it.

Effects of the Invention The positive photoresist composition of the present invention contains naphthoquinone-1,2-diazide-5-sulfonic acid tetraester of 2.3.4.4'-tetrahydroxybenzophenone or 7-toquinone-1,2 as a photosensitive component. -Diazide-4-
A sulfonic acid tetraester is used, which has extremely good compatibility with the solvent, so when the composition is used as a solution, precipitation of fine crystals over time is not observed. Further, the photosensitive component is the conventionally known 21314-1
7-hydroxybenzophenone naphthoquinone-1,2-
It has superior sensitivity and heat resistance compared to diazide sulfonic acid triester.1 For example, when the same alkali-soluble resin is used and the blending ratio of the resin and the photosensitive component is the same, the uninvented composition has + 2.3. It has about 1.5 times the sensitivity of a composition using naphthoquinone-1,2-diazide sulfonic acid triester of 4-trihydroxybenzophenone, and is also superior in heat resistance by about 30°C. ing.

As described above, since the composition of the present invention has excellent sensitivity and heat resistance, it is possible to use the composition for image formation with less exposure to ultraviolet rays than when using conventionally known compositions. The time required to form an image is shortened and work efficiency is improved. Furthermore, the composition of the present invention has excellent dry etching resistance, and when used as a solution as described above, it is an excellent photosensitive material with no foreign matter generated over time. It is suitably used as a resist for ultrafine processing in device manufacturing.

Example Next, the 'X invention will be explained in more detail with reference to Examples.

Synthesis Example 1 2.3.4.4'-Tetrahydroxybenzophenone 9
．． 8 t (0.04 mol) and naphthoquinone-1,2-
Diazide-5-sulfonyl chloride 26.8 f (0
, 10 mol) of dioxane 340? Dissolve in this and add 2
5. Aqueous sodium carbonate solution 249 was added dropwise over 30 minutes to 1 hour while stirring thoroughly. Then 35% hydrochloric acid 2
5? A dilute salt rR bath solution diluted with 1000 tons of ion-exchanged water was added to precipitate the reaction product, and the resulting precipitate was thoroughly washed with ion-exchanged water, water was removed, and then dried.

The dried product thus obtained was dissolved in tetrahydrofuran and washed with a Hitachi 655 liquid chromatograph [(Hitachi IR), 3 columns 5hoaex KF-301 (manufactured by Showa Denko K.K.) and GPC Kara A)], UVTDK.
C-100! Using a V-type ultraviolet detector (manufactured by JASCO Corporation).

As a result of analysis at a wavelength of 310 nm, the composition according to the sensitivity at a wavelength of 310 nm is 2 tetraesters in area ratio.
6.4%, diester 37.1%, mononis f k 2
The result was 4-2 excellent, and the unexhausted product was 12.3 poor.

Mata, gel permeation chromatography (GPC)
), only four peaks of one reaction product were detected, and based on their retention times, it was assumed that they were tetraester, diester, monoester, and unreacted products. However, its existence was not confirmed.

Synthesis Example 2 The reaction product of Synthesis Example 1 was completely dissolved in 10ft-acetone 502, and then left to stand to precipitate. The precipitate was dried and the acetone was evaporated from the filtrate to obtain a sticky paste-like substance.

According to the GPC20 analysis results of the dried material and pasty material, the dried material is a tetraester with a purity of 99% or more.

The paste was a mixture of 3% tetraester and the remainder consisting of diester, monoester, and unreacted materials.

Reference example 1 2.3.4-trihydroxybenzophenone 9.2t (
The reaction was carried out under the same charging ratio and reaction conditions as in Synthesis Example 1, except that 0.04 mol)' was used, and the resulting reaction product was found to have 53.6% triesters, 29.7% diesters, and 29.7% monoesters as a result of GPC20 analysis. Ester 11.3%.

The amount of unreacted substances was 5.4%.

Reference Example 2 The reaction product 10F of Reference Example 1 was mixed with acetone 50? After complete dissolution, the precipitate was left to stand and the precipitate was removed.The solution was treated in the same manner as in Synthesis Example 2, and the resulting dry powder and paste-like substance were analyzed by GPO.

The dry powder is a triester with a purity of 99% or more.

The paste-like material had a triester content of less than 10%.

Examples 1-3. Comparative Example 1.2 Cresol novolac resin (molecular weight 30,000, converted to holisterene) 8? In contrast, each of the reaction product 1 of Synthesis Example 1, the dried substance and paste-like substance of Synthesis Example 2, and the dry substance and paste-like substance of Reference Example 2 as photosensitive components was mixed with 23.3 of ethylene glycol monoethyl ether acetate.
f to form a photoresist composition, each of these was applied to a silicon wafer using a scrubber, and dried on a hot plate at 110°C for 90 seconds to give a film thickness of 1.3 μm.
A resist film of m was obtained. This film was exposed to light at 0.2 second intervals from 1 second to 5 seconds using an ultra-high pressure mercury lamp exposure device (Canon Inc. 1!PLA-500), and then exposed to a 2.38% tetramethylammonium hydroxide aqueous solution. The appearance after developing for 1 minute, washing with water for 30 seconds, and drying was measured as the appropriate exposure time (minimum time required for patterning).

Next, the resist patterns of the silicone wafer thus obtained were heated at 130°C, 140°C, and 15°C, respectively.
The pattern was beta-tested at each temperature of 0° C., 160° C., and 170° C. for 20 minutes, and the presence or absence of deformation of the pattern was evaluated as heat resistance. The following table shows the measurement results of sensitivity and heat resistance.

As can be seen, the tetraester of 2.3.4.4'-tetrahydroxybenzophenone is 2.3.4
- Superior in both sensitivity and heat resistance compared to triester of trihydroxybenzophenone.

Furthermore, when a paste-like material is used, the etch rate of unexposed areas is fast, and the resistance of the resist film tends to be weak.

Example 4.5. Comparative Examples 3 to 5 Example 4.5 and Comparative Example 4.5 are each Example 9iJ2
．． When preparing the photoresist compositions in No. 3 and Comparative Examples 1 and 2, the blending ratio of Talesol novolac resin and photosensitive component was determined by adjusting the ratio of naphthoquinone-1,2-diazide
In order to keep the amount of 5-sulfonyl group constant, the absorbance of Talesol novolac resin (absorbance at a sensitive wavelength of 280 nm' fJlI Abs 28G
) and the absorbance of 7-toquinone-1,2-diazide-5-sulfonyl group (absorbance at a photosensitive wavelength of 345 nm [Ab8345
) is constant, i.e. Abs 280/Abs
345-3.90, otherwise Example 2
, 3 and the same method as Comparative Examples 1 and 2.

Sensitivity and heat resistance were measured by adjusting the conditions.

In Comparative Example 3, a photoresist composition was prepared in the same manner as described above, except that the reaction product of Reference Example 1 was used as a photosensitive component, and the sensitivity and heat resistance were measured. These results are shown in the table below.

As can be seen, the tetraester tL of 2,3,4,4'-tetrahydroxybenzophenone is superior in both sensitivity and heat resistance to the triester of 2.3°4-trihydroxybenzophenone.

Comparative Example 6 A reaction was performed under the same conditions as in Synthesis Example 1 except that 9.82% of 2.2',4.4'-tetrahydroxybenzophenone was used, and the resulting reaction product was subjected to GPO analysis.

Tetraester and diester are each 73.4%.

23 and 14, the reaction product was concentrated at 3.5%. 2t of this reaction product and 8ft of Talesol novolak resin (molecular weight 30,000, polystyrene equivalent) were dissolved in 23.3f of ethylene glycol monoethyl ether acetate.
1-5. Comparison 9jl The compatibility of each photoresist composition obtained in Examples 1 to 5 was compared.

As a result, in Examples 1 to 5 and Comparative Examples 1 to 5,
Even after one week had elapsed, no precipitates were observed in the photoresist composition, but in some cases, precipitates were deposited.

Claims (1)

[Claims] 1 For alkali-soluble resins, there are general formulas▲mathematical formulas, chemical formulas, tables, etc.▼ (D in the formula is naphthoquinone-1,2-diazide-5-sulfonyl group or naphthoquinone-1,2- diazide-4-
1. A positive photoresist composition comprising a compound represented by the formula (sulfonyl group). 2 General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (D in the formula is naphthoquinone-1,2-diazide-5-sulfonyl group or naphthoquinone-1,2-diazide-4-
2. The composition according to claim 1, wherein the content of the compound represented by (which is a sulfonyl group) is 5% by weight or more in the photosensitive component.