JPH01233447A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To suppress the generation of a crack, and to improve the coating property and the difinition of the composition by incorporating a specified compd. bound with o-nitrobenzyloxycarbonyl group to the part or the whole of a hydroxyl group contd. in phenol, cresol or xylenol. CONSTITUTION:The composition is composed of the mixture of a resin contg. a phenol, a cresol or a xylenol skeleton and a dissolving inhibitor. The compd. bound the o-nitrobenzyloxycarbonyl group shown by formula I to the part or the whole of the hydroxyl group contd. in the phenol, the cresol or the xylenol is incorporated in the composition. In formula I, R1-R4 are each hydrogen, halogen atom. or alkyl group, etc. Thus, the coating property of the composition is reduced, and the generation of the crack is removed, and also the composition having the excellent difinition is obtd.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a photosensitive composition that uses ultraviolet light as the exposure wavelength, and more specifically, to a photosensitive composition that is alkaline developable and free from the risk of cracking. The present invention relates to a sexual composition.

(Prior Art) Photosensitive compositions are indispensable for forming fine patterns in the manufacture of semiconductor devices, and positive-type photosensitive compositions are mainly used in general manufacturing lines. Typical examples of these include novolac resins that are soluble in alkaline developers, and dissolution inhibitors (such as 1,2-naphthoquinonediazide sulfonate esters) that make the base resin resistant to alkaline developers. photosensitizer)
There is a mixture of

In addition, as a negative type that is developed with an organic solvent, the hydroxyl group of novolak is directly esterified with 1,2-naphthoquinonediazide sulfonic acid (Fuji Pharmaceutical Co., Ltd.,
LMR-UV).

The pattern formation mechanism of such a photosensitive composition is mainly based on the change in polarity (solubility in a developer) of the 1,2-naphthoquinonediazide derivative before and after light irradiation. Therefore, the larger the difference in dissolution rate between the exposed portion and the unexposed portion, the better the pattern resolution.

Since the aforementioned mixture of novolac resin and 1,2-naphthoquinone diazide sulfonic acid ester satisfies the aforementioned properties, its usage may increase in the future as patterns become finer. It is said that

By the way, in such a system, the high solution is 11! In an attempt to improve the temperature, a photosensitive substituent was introduced into the phenolic hydroxyl group of the polyvinylphenol resin, and this substituent was eliminated by a photoreaction before and after exposure, thereby changing the solubility of the polyvinylphenol resin itself. A method for obtaining a synergistic effect with a dissolution inhibitor has been disclosed (for example, JP-A No. 62-69263). In this example, an 0-nitrobenzyl group is used as the photosensitive group and is directly bonded to the phenol water W group of the polyvinylphenol resin. In this case, it is desired to introduce as much of the 0-nitrobenzyl group into the resin as possible in order to improve their resolution.

(Problem to be solved by the invention ff1) However, it is difficult to introduce more groups into polyvinylphenol resin due to steric hindrance caused by the above-mentioned 0-nitrobenzyl group.
Furthermore, when a large amount is introduced, there are problems such as the paste resin becoming insoluble in the coating solvent and cracks occurring after coating. Such problems are found not only in polyvinylphenol resins but also in cresol novolac resins and xylenol novolak resins having a phenol skeleton as base resins, and among cresol novolac resins, these problems were particularly noticeable in para-substituted resins.

This invention is directed to the above-mentioned photosensitive group 0-nitrobenzyl, which is difficult to introduce in large quantities into a resin having a phenol skeleton, etc., and also because it becomes insoluble in the coating solvent when introduced in large quantities, and the coating properties are poor. It is an object of the present invention to provide a photosensitive composition with excellent resolution by eliminating problems such as a decrease in image quality and generation of cracks.

(Means for Solving the Problems) This invention uses ultraviolet rays as the exposure wavelength, and in a photosensitive composition that is a mixture of a paste resin and a dissolution inhibitor,
An 0-nitrobenzyloxycarbonyl group is introduced into the base resin as a photosensitive group.

That is, the present invention provides a photosensitive composition comprising a mixture of a resin having a phenol skeleton, a cresol skeleton, or a xylenol skeleton and a dissolution inhibitor (photosensitizer),
Some or all of the hydroxyl groups of the above-mentioned phenol, cresol or chirelenol have the general formula, (wherein R7 to R4 are hydrogen, halogen (chlorine, bromine, fluorine), 2-alkoxy group (methoxy group).

ethoxy group), alkyl group (methyl group, ethyl group, isopropyl group, t-butyl group).

selected from. ) A photosensitive composition characterized by containing a compound having an O-nitrobenzyloxycarbonyl group bonded thereto.

In the present invention, the resin having a phenol skeleton, cresol skeleton, or xylenol skeleton includes, for example, hapolyvinylphenol p vinylphenol.

Methyl methacrylate copolymer, vinylphenol methacrylic acid copolymer, vinylphenol methacrylate hydroxyethyl copolymer, cresol novolak resin (Or
(including copolymers of isomers of p-)
Crucible resins, resol xylenol novolak resins, cresol ubivinylphenol, copolymers of xylenol and acrylonitrile, styrene, etc. can be mentioned. Of course, mixtures of two or more of the polymers listed here or mixtures of one or more of the above resins with other resin components can also be used as long as they are soluble in an aqueous alkaline solution. .

Next, specific examples of the 0-nitrobenzyloxycarbonyl group to be introduced into the hydroxyl group of phenol, cresol or xylenol include those shown in the following formula.

A precursor for introducing such a substituent is phosgene and
It can be synthesized as chloroformates obtained by reacting with the corresponding benzyl alcohol derivative in a 1:1 molar ratio. The introduction of the substituent is carried out by introducing the obtained 0-nitrobenzyl chloroformate into a resin solution in the presence of an amine such as triethylamine or pyridine.
This is achieved by dropwise reaction at temperatures between .degree. C. and room temperature.

The introduction ratio of the O-nitrobenzyloxycarbonyl group to the hydroxyl group of the phenol, cresol or xylenol is in the range of 20 to 80%, and although sensitivity decreases, it is desirable to have as much as possible in order to improve resolution. This is because if the introduction rate is less than 20%, patterning is almost impossible, and if too large a quantity is introduced, solubility and coating properties may be impaired.

Examples of the dissolution inhibitor (photosensitizer) used in the photosensitive composition of the present invention include 1,2-naphthoquinone-2-diazide-4-sulfonic acid, 2,3,4-tri,doxybenzophenone, or 2.3.4゜4'-tetrahydroxybenzophenone or methyl gallate or pyrogallol in which part or all of the hydroxyl groups are esterified, or 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester; 2,3.4-trihydroxybensibuenone or 2.3.4.4'-tetrahydroxybenzophenone or methyl gallate or pyrogallol in which part or all of the hydroxyl groups are esterified, 1,2-benzoquinone- Part or all of the hydroxyl groups of 2-diazide-4-sulfonic acid and 2,3,4-trihydroxybenzophenone, 2,3°4,4'-tetrahydroxybenzophenone, methyl gallate, or pyrogallol are esterified. Things, etc. can be mentioned. These dissolution inhibitors (photosensitizers) can be used alone or as a mixture of two or more.

The photosensitive composition of the present invention is dissolved in an organic solvent such as cyclohexanone, ethyl cellosolve acetate, methyl cellosolve acetate, methyl isobutyl ketone, methyl ethyl ketone, or anisole, and used by spin coating on a silicon wafer. Then, as usual, after drying in a vacuum adsorption oven, UV exposure (
200-450 nm) Lt, pattern formation is performed by cleaning with an alkaline aqueous solution and drying. As the aqueous alkali solution, an aqueous solution of an organic alkali such as tetramethylammonium hydroxide, triethanolamine, or (2-hydroxyethyl)ammonium hydroxy, or an inorganic alkali such as sodium hydroxide, potassium hydroxide, or aqueous ammonia is used.

A dye is added to this photosensitive composition i*wl as necessary.

Additives such as plasticizers, adhesives, development accelerators, and surfactants may be used in combination.

(Function) The mechanism of action of the photosensitive composition solution of the present invention, which has the above-mentioned particularly good coating properties and does not cause cracks, is that the photosensitive composition solution of the present invention has low steric hindrance due to the above-mentioned three-dimensional structure. This is thought to be due to the fact that the introduction of the benzyloxycarbonyl group reduces the strain in the molecule.

Furthermore, the improvement in resolution is thought to be due to the action of causing a polarity change in the resin itself, without depending on the polarity change of the dissolution inhibitor alone.

(Example) The present invention will be specifically explained below using examples.

Example 1 Weight ratio of phosgene and O-nitrobenzyl alcohol: 1
: One composition was prepared by the above synthesis method. - 70 g of nitrobenzyl chloroformate, 50 g of polyvinylphenol [Mw = 8.000 manufactured by Maruzen Petrochemicals], 50 g of triethylamine, and 500 mL of 1.4-dioxane.
The mixture was added dropwise over 60 minutes to a solution that had been dissolved in water and cooled with water. Thereafter, the mixture was stirred overnight at room temperature, the resulting salt was filtered, and the mixture was poured into 21 water. The resulting precipitate was filtered, washed three times with 11 portions of water, and dried to obtain 80 g of 0-nitrobenzyloxycarbonate of vinylphenol.

The carbonate esterification rate was approximately 70% as determined by NMR.

Ester 3 prepared from 20 g of the obtained resin and 2.3.4.4'-tetrahydroxybenzophenone 1.2-naphthoquinone-2=diazide-4-sulfonic acid chloride
．． After dissolving 5 g in 90 mL of ethyl cellosolve acetate, 1 pm and 0.45 μm, then 0.2 μm
A resist solution was prepared by filtration through a filter.

Using this resist solution, a Debite region bake was performed at 200°C for 1 minute, and then it was coated with a spinner on a silicon wafer that had been subjected to OAP (hexamethyldisilazane manufactured by Tokyo Ohka) vapor treatment for 1 minute at room temperature. Dry on a hot plate at 100°C for 1 minute, 1.07
A photoresist film with a thickness of μm was obtained. This substrate was processed using a G-line reduction projection exposure device (numerical aperture 0.35, manufactured by Nippon Kogaku).
Test reticle (homemade 0.5μm, 0.55μm, 0.
6 μm.

After printing a test pattern using a 0.7 μm line and space pattern (including a 0.7 μm line-and-space pattern),
Deep development was performed for 0 seconds. Thereafter, it was dried for 1 minute on a vacuum adsorption hot plate at 105°C. SEMQ
As a result of the investigation, a 0.6 μm line and space was visualized.

Comparative Example 1 The same procedure was used as in Example 1 except that 15 g of polyvinylphenol, which was not subjected to carbonic acid esterification as described above, was used as the base resin for the resist solution. The 0017 μm line and space pattern was resolved.

Comparative Example 2 As a resin, polyvinylphenol (etherification rate 70%) which had been subjected to 0-nitrobenzyl etherification as described above as one of the conventional techniques was synthesized. When a resist solution was prepared and coating was performed in the same manner as in Example 1, many cracks occurred around the wafer.

Example 2 Para-cresol novolac resin 50 purified as a resin
A resist solution was prepared in exactly the same manner as in Example 1, except that G was used, and pattern formation was performed in the same manner. SEM
When Li inspection was performed, a 0.55 μm line and space pattern was resolved.

Comparative Example 3 A pattern was formed in exactly the same manner as in Example 1, except that the resin was subjected to the above carbonate esterification and 50 g of para-cresol novolak resin was used as it was as a paste resin for resist. As a result of SEM observation, 0.
An 8 μm line and space pattern was resolved.

Comparative Example 4 The above-mentioned 0-nitrobenzyl etherification e was used as the resin. An attempt was made to prepare a resist solution in exactly the same manner as in Example 1 except for using 20 g of para-cresol novolak resin (etherification rate 70%), but the solvent ethyl cellosolve acetate (which is extremely difficult to dissolve) When the filtered solution was used to spin-coat a silicon wafer, it was not possible to increase the thickness of the film, and cracks appeared from the periphery.

Example 3 After adding 10 g of the resin synthesized in Example 1 to the resist solution prepared in Example 1, the same solution was applied on a 2-inch silicon wafer, and 10 g of resin was added in the same manner.
．． A photosensitive layer of 0.05 μm was obtained.

Using a deep ultraviolet contact exposure device (PLA-5213 manufactured by Canon), a test pattern was exposed using a self-made mask with light that had passed through a CM-250 cold mirror. Similarly, development was performed and cross-sectional SEM II observation was performed, and 0.4 μm lines and spaces were resolved.

Example 4 To the resist solution prepared in Example 2, 10 g of the carbonate-esterified resin synthesized in Example 2 was further added and filtered in the same manner to prepare a resist solution. This was exposed and developed in the same manner as in Example 3, and the cross section SE
When Mii observation was performed, 0.4 μm line and space was resolved.

(Effects of the Invention) As described in detail above, according to the photosensitive composition of the present invention, since an 0-nitrobenzyloxycarbonyl group is bonded as a photosensitive group, Even if the content of the photosensitive group is increased, it is possible to provide a photosensitive composition in which the solubility does not decrease or cracks occur as in the above-mentioned conventional methods, the coating properties are significantly improved, and the resolution is significantly improved. There is, and the effect of its industrial use is extremely large.

Furthermore, the photosensitive composition of the present invention can be applied to a reduction projection exposure method using a KrF excimer laser as a light source, which has been attracting attention recently, and has effects such as making ultra-fine patterns possible. .

Claims (1)

[Scope of Claims] A photosensitive composition comprising a mixture of a resin having a phenol skeleton, a cresol skeleton or a xylenol skeleton, and a dissolution inhibitor (photosensitizer), wherein some of the hydroxyl groups of the phenol, cresol or xylenol are Or all of them have general formulas, ▲mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 to R_4 are hydrogen, halogen (chlorine, bromine,
fluorine), alkoxy groups (methoxy group, ethoxy group),
Alkyl group (methyl group, ethyl group, isopropyl group, t
-butyl group). 1. A photosensitive composition comprising a compound having an o-nitrobenzyloxycarbonyl group bound thereto.