JPS6327835A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having less tendency for swelling during processing, and improved anti-dryetching property by incorporating a condensation product of a specific halogenonaphthoquinone diazide compd. and a phenolic hydroxy group-contg. compd., and a novolak resin to the titled composition. CONSTITUTION:The titled composition comprises the condensation product of halogenonaphthoquinone diazide compd. shown by formula I and the phenolic hydroxy group-contg. compd., and the novolak resin to the titled composition. In formula I, at least one of X1-X3 groups is halogen atom, another of which is hydrogen atom. The positive type photoresist composition for forming an ultrafine pattern high in dimensional accuracy and having an excellent anti-dry etching property and less tendency for swelling during processing is obtd. by combinating said photosensitizing agent and the novolak resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to positive photoresist compositions. More specifically, the present invention relates to a positive photoresist composition for forming fine patterns with high dimensional accuracy, which is suitably used for manufacturing semiconductor integrated circuit elements such as VLSIs.

Conventional technology In recent years, in the semiconductor industry, industrial computers,
The demand for office automation, personal computers, etc. is expanding dramatically, and the technology for these devices continues to advance rapidly. Along with this, semiconductor integrated circuit devices are also rapidly becoming denser and more highly integrated. I'm here.

Also, in fine pattern formation, 256 kilobits)
The pattern width of semiconductor integrated circuit elements for DRAM is approximately 2μ.
m, 1.0 to 1.3 μm for 1 megapit DRAM,
Furthermore, as DRAM (4 megapixels) is integrated with a size of 0.7 to 0.8 μm, microfabrication technology on the so-called submicron order is becoming necessary.

Regarding this submicron order pattern formation,
The combination of positive photoresist and reduction projection exposure method allows
Although pattern resolution at 5μmi is becoming possible,
Since the wavelength of ultraviolet rays used in photolithography using the positive photoresist is 350 to 450 nm, it is impossible to resolve patterns of 0.5 μm or less, and this fine pattern of 0.5 μm or less is impossible. For K to be processed, it is necessary to use lithography using active radiation other than ultraviolet rays, such as electron beams or X-rays.

By the way, in order to increase the sensitivity of resists to electron beams and No. 10, p. 61 (1979), Journal of the Electrochemical Society (J, Electrochem,
Soc, ) J Volume 126, Page 1635 and Volume 1
829 (1979)], these resists use a main chain-cleaved polymer, and therefore have the disadvantage of poor dry etching resistance.

On the other hand, in etching for forming patterns in the submicron region, the wet etch leg method is difficult for the etching solution to penetrate into the gaps between the patterns, resulting in etching failure. Since micron patterns cannot be obtained, dry etching is often used. Therefore, resist materials for submicron processing are required to have dry etching resistance.

The polymer used for this dry etching-resistant resist is preferably one made of an aromatic compound that suppresses benzene nuclei; one example is a negative resist using chloromethylated polystyrene. . However, this negative resist has problems such as swelling in a developer, and high resolution patterns cannot be obtained.

Problems to be Solved by the Invention The present invention provides a highly dimensionally accurate ultra-thin film that has excellent dry etching resistance, does not swell in a developer, and is suitable for the development of semiconductor integrated circuit devices such as ultra-LSIs. The purpose of this invention is to provide a positive photoresist composition for forming fine patterns.

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive research and have developed a photosensitizer obtained by an esterification reaction between a certain type of halogenonaphthoquinone diazide compound and a compound containing a phenol hydroxide group. is not only felt by ultraviolet rays, but also
It has high sensitivity to electron beams and X-rays, and it was discovered that the purpose could be achieved by combining this photosensitive agent with a novolac resin stopper.Based on this knowledge, the present invention was completed. It's arrived.

That is, the present invention provides a halogenonaphthoquinonediazide compound represented by the general formula (4) (at least one of Xl, X2, and X3 in the formula is a halogen atom, and the others are hydrogen atoms) and a phenol hydroxide group. The object of the present invention is to provide a positive photoresist composition comprising a condensation product with a containing compound and (B) a novolak resin.

Hereinafter, one aspect of the present invention will be explained in detail.

Examples of the halogenonaphthoquinone diazide compound represented by the general formula (1) or (It) used as a raw material for the photosensitive component (4) in the composition of the present invention include 5-fluoro-naphthoquinone-1,2 -Diazide-
4-sulfonyl chloride, 6-fluoro-naphthoquinone-1,2-diazide-5-sulfonyl chloride, this 2
Fluorine atoms in two compounds are 3-fluoro, 5-fluoro,
Fluoro, 6-fluoro, 7-fluoro, 8-fluoro, a,S-difluoro, 3.6-difluoro, 3.
7-difluoro, 3,8-difluoro, 5,6-difluoro, 5,7-difluoro, 5,8-difluoro, 6,
7-difluoro, 6.8-difluoro, 7.8-difluoro, 3.5. Foot trifluoro, 3,5. Rotrifluoro, 3,5.8-trifluoro, 3,6. foot trifluoro, 3.6.8-trifluoro, 3.7.8-)
Examples include refluoro-substituted compounds and compounds in which the fluorine atom of these compounds is replaced with a chlorine atom, bromine atom, or iodine atom.

Examples of the phenolic hydroxyl group-containing compound, which is the other raw material for component (4), include alkyl gallate,
Polyhydroxybenzophenones, such as tetrahydroxybenzophenone, or trihydroxybenzene,
Trihydroxybenzene monoethers, '2.2'
, 4.4'-tetrahydroxydiphenylmethane, 4+
4'-dihydroxydiphenylpropane, 4.4'-dihydroxydiphenylsulfone, 2.2'-dihydroxy-1,1-dinaphthylmethane% 2-hydroxyfluorene, 2-hydroxyphenanthrene, polyhydroxyanthraquinone, purprogalin and its derivatives, Examples include phenyl 2,4.6-dolyhydroxybenzoic acid ester.

The photosensitive component used in the composition of the present invention is a condensation product obtained by subjecting the halogenonaphthoquinonediazide compound described above to an esterification reaction with a phenolic hydroxyl group-containing compound. This esterification is carried out by dissolving the halogenonaphthoquinonediazide compound and the phenolic hydroxyl group-containing compound in a predetermined ratio in a solvent such as tetrahydrofuran, and then adding a hydrogen chloride scavenger such as triethanolamine to the solution. After adding a sufficient amount to carry out the esterification reaction, and then separating the precipitated hydrochloride of the scavenger by means such as filtration, the solvent in the solution is distilled off to collect the reaction product. This can be done by

In the composition of the present invention, examples of the novolak resin used as component (B) include phenol novolak resin, talesol novolak resin, and phenol-alkylphenol cocondensation novolak resin.

In the composition of the present invention, the photosensitizer is a novolac resin 1
00 parts by weight, 3 to 60 parts by weight, preferably 5 to 60 parts by weight
It is desirable to use it in a range of 30 parts by weight. This amount is 3
If it is less than 6 parts by weight, the film loss in the unexposed area will be large;
If it exceeds 0 parts by weight, the sensitivity decreases, which is not preferable.

The positive photoresist composition of the present invention is preferably used in the form of a solution by dissolving the above-mentioned 7-borac resin and photosensitizer in a suitable solvent.

Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, isoamyl ketone; monomethyl ether, monoethyl ether, monopropyl ether, motubutyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate. Also, polyhydric alcohols such as hamonophenyl ether, their derivatives, cyclic ethers such as dioxane, and esters such as methyl acetate, ethyl acetate, butyl acetate, etc.: methyl, ethyl or butyl ether of propylene glycol, methyl of propylene glycol. , ethyl or butyl ether acetate.

These solvents may be used alone or in combination of two or more.

The positive-working photoresist compositions of the present invention may further contain conventionally compatible additives such as additional resins, plasticizers, stabilizers or colorants to make the developed image more p-layer visible. It is possible to add and contain the following substances.

To give an example of a preferred method of using the composition of the present invention, first, a solution of a novolak resin and a photosensitizer dissolved in an appropriate solvent is applied onto a support such as a silicon wafer using a spinner, and then dried. to form a photosensitive layer. Thereafter, exposure is performed through a required mask using a reduction projection exposure device or the like. Next, add this to a developer, for example 2
When developed using an aqueous solution of tetramethylammonium hydroxide or choline in an amount of ~5 weight, it is possible to obtain an image faithful to the mask pattern in which the portions solubilized by exposure are selectively dissolved and removed.

Effects of the Invention The positive photoresist composition of the present invention is a composition containing a photosensitive agent having a halogenonaphthoquinonediazide group and a novolac resin, and is capable of providing a submicron ultra-fine resist pattern by electron beam or X-ray exposure. The resist (turn) does not swell even during development and has high dry etching resistance, so it is suitably used for manufacturing semiconductor integrated circuit elements such as VLSI.

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

Synthesis Example 7 - 63.7 parts by weight of promonaphthoquinone-1,2-diazido-4-sulfonyl chloride and 19.0 parts by weight of 2.3.4-trihydroxybenzophenone were dissolved in 700 parts by weight of tetrahydrofuran, and then heated to 20°C or lower. A solution of 14.9 parts by weight of triethanolamine dissolved in tetrahydrofuran at a concentration of 10% by weight was added thereto after being cleaved for about 1 hour. Next, the precipitated triethanolamine hydrochloride was filtered off, 10 parts by weight of 1% by weight hydrochloric acid was added to the filtrate, and the mixture was neutralized by stirring. After 90% of tetrahydrofuran was distilled off, water was added. The reaction product was precipitated. Next, this reaction product was taken out, washed several times with water, and then dried in vacuo.
, 45 parts by weight of 4-trihydroxybenzophenone ester were obtained.

Example 1 In the synthesis example, 10 parts by weight of Tokken photosensitizer and 100 parts by weight of cresol novolac resin were dissolved in 600 parts by weight of ethylene glycol monoethyl ether acetate, and the pore size was 0.2 μm.
A film of the photosensitive layer obtained by baking it on a 4-inch silicon wafer at 90°C for 90 seconds using a resist coater TR-5111 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) after filtering it using a Teflon filter of Thickness is 0.5μm
It was applied so that it became K.

This Ueno-- is exposed to Nippon Kogaku Kogyo Co., Ltd.'s reduction projection exposure system N.
5R-150503A was exposed through a test chart mask, and then immersed in a 2.38 wt% aqueous solution of tetramethylammonium hydroxide (23°C) for 35 seconds. I was able to form the pattern perfectly. The resolution at this time was 0.6 μm.

Example 2 Using the solution of the photoresist composition of Example 1, a photosensitive layer with a thickness of 0.5 μm was obtained in the same manner, and a scanning electron microscope arm (manufactured by Hitachi, Ltd., HH8-RR type) was attached to this photosensitive layer. Using an improved electron beam irradiation device, irradiation was performed at an acceleration voltage of 20 kV, an irradiation current of 10''li A, and a spot diameter of 136 μm. When immersed and developed for 35 seconds, the minimum irradiation amount (sensitivity) required for pattern formation
was I X 1O-5Cj/d. Also 0.05μ
When a line was drawn with a beam of 0.5 μm, a line-and-space pattern of 0.5 μm was obtained.

The resulting resist pattern was irradiated with a low-pressure mercury lamp of 8 mW/ad for 20 minutes at 250°C.
No deformation of the pattern was observed even after 30 minutes of heat treatment.

Comparative Example 1 Positive type photoresist) 0FDR-1000 (naphthoquino/diazide-cresol novolak system) 15CPi Coated to a film thickness of 0.5 μm under the same conditions as Example 2, baked, and then irradiated with electron beam, the sensitivity was 4XIO- '(:
! It was /-.

Example 3 A resist pattern of 065 μm obtained in the same manner as in Example 1 was irradiated with ultraviolet rays for 2 minutes over the entire surface using a 5 kW ultra-high pressure mercury lamp having an intensity of 185 mW/crl at 365 nm, and then heated at 250° C. for 30 minutes. Beta'd for a minute. Next, this resist pattern was etched using an OAPM-301B plasma etching device (manufactured by Tokyo Ohka Kogyo Co., Ltd.).
Uses C1F3 gas, output 150W, vacuum degree 66.7
When dry etching was performed under conditions of Pa and temperature of 100° C., the rate of film reduction of the resist pattern film was Zoo nm/min.

Comparative Example 2 A photoresist solution obtained by dissolving polymethylacetate and methacrylate in cyclopentanone was used and treated under the same conditions as in Example 2 and irradiated with an electron beam, followed by a solution of isoamyl acetate: ethyl acetate = 9 = 1. The sensitivity was sxto-'c/lri. When the obtained resist pattern was subjected to beta testing at 250° C. for 30 minutes, the resist pattern was deformed into a rounded shape.

When this resist pattern was processed under the same dry etching conditions as in Example 2, the film reduction rate was 4.
00 nm/min.

Example 4 5.7-cyclonaphthoquinone-1,2-diazide-4
-10 parts by weight of sulfonic acid-2,3,4-1 hydroxybenzophene nonester and 1 part of Talesol novolac resin
The same procedure as in Example 2 was used, except that a photoresist solution obtained by dissolving 00 parts by weight of ethylene glycol monoethyl ether acetate in 60 parts by weight of ethylene glycol monoethyl ether acetate and filtering the solution using a Teflon filter with a pore size of 0.2 μm was used. When the sensitivity was measured under these conditions, it was 8×10 C/i. Further, when the obtained resist pattern was irradiated with a low pressure mercury lamp of 8 mW/i for 20 minutes, no deformation of the pattern was observed even after heat treatment at 250° C. for 30 minutes.

Regarding this product, the film reduction rate of the resist pattern film was examined in the same manner as in Example 3, and the result was 1100 n/min.

Example 5 10 parts by weight of 7-fluoronaphdoquinone-1,2-diazide-5-sulfonic acid-2,2',4,4'-tetrahydroxybenzophenone ester, phenol, and ter
Sensitivity was evaluated under the same conditions as in Example 2, except that the entire photoresist solution obtained by dissolving 100 parts by weight of a novolac resin containing t-butylphenol as a constituent in 600 parts by weight of ethylene glycotamonoethyl ether acetate was used. When measured, it was IX 1O-5C/aA. In addition, as in Example 4, the heat resistance of the obtained resist pattern was examined. As a result, no deformation of the resist pattern was observed even after heat treatment at 250°C for 30 minutes◇
Regarding this product, the film reduction rate of the resist pattern film was investigated in the same manner as in Example 3, and the result was 1100 n/min.
Met.

Claims (1)

[Claims] 1 (A) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (At least one of x_1, x_2, and x_3 in the formula
A positive photoresist composition comprising a condensation product of a halogenonaphthoquinonediazide compound represented by the following formula (in which one is a halogen atom and the other is a hydrogen atom) and a phenolic hydroxyl group-containing compound, and (B) a novolak resin.