JPS63284545A - Negative type photoresist composition - Google Patents

Abstract

PURPOSE:To obtain a fine resist pattern by using a specific phenol novolak resin and arom. azide compd. which absorbs light of a specific wavelength range to constitute a negative type photoresist compsn. adequate for lithography by deep UV and excimer laser. CONSTITUTION:The substd. phenol novolak resin consisting of a mixture composed of the phenols expressed by the formula and formaldehyde and the arom. azide compd. which absorbs light of <=350mm wavelength are used at the time of forming the negative type photoresist compsn. In the formula, R1 denotes an alkenyl group or alkenyloxy group; R2 denotes a hydrogen atom., hydroxyl group, alkyl group, alkenyl group or alkoxy group. Phenols contain a substituent having carbon-carbon double bonds and is, for example, 2-(1-propenyl)phenol, etc. 4,4'-diazide diphenyl sulfide, etc., are used for the arom. axide compd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel negative photoresist composition. More specifically, the present invention relates to a negative photoresist composition suitable for microfabrication in the manufacture of semiconductor devices, particularly sensitive to deep UV or excimer laser.

BACKGROUND OF THE INVENTION In recent years, there has been remarkable progress in increasing the density and integration of semiconductor integrated circuits, and resolution accuracy in microfabrication technology is now required down to the submicron range. As for the lithography technology that is the mainstream of the semiconductor manufacturing industry, microfabrication of 0.5 μm or less is required, and in order to meet this requirement, the wavelength range is 200 to 600 μm.
DθepUV lithography, which uses ultraviolet light (DeθpUv) with a short wavelength of 00 nm for exposure, has been proposed. In deep UV lithography, exposure equipment that uses a xenon-mercury lamp as a light source is often used, but recently excimer lasers have been developed, and DeθpUV
It is attracting attention as a light source. The most commonly used excimer laser is the iFL laser (wavelength: 248 nm), but research has also been conducted on photoresists that are compatible with it, and so far, chloromethylated polystyrene and polyvinylphenol have been used. A negative-type photoresist comprising a mixture of and an aromatic bisazide compound has been developed (Japanese Patent Publication No. 8777/1983). However, this negative photoresist has the drawback of insufficient resolution. Further, a deep UV negative photoresist composition comprising a phenol novolac resin and a bisazide compound is also known. however,
In lithography used in the manufacture of semiconductor devices,
After a resist pattern is formed on the substrate, the entire surface is irradiated with ultraviolet rays to improve thermal strength, and then the etching process is carried out. With the trend towards miniaturization,
Dry etching methods such as plasma etching and active ion etching are now being used, and resist patterns with excellent heat resistance are desired, but this negative photoresist has poor heat resistance. It is not sufficient and has the disadvantage that the resist pattern sag at temperatures above 150°C.

In this way, the D
Negative photoresists that use eep UV or excimer lasers or are used in lithography have not yet been produced for practical use, so the semiconductor manufacturing industry is looking for resists with excellent resolution and improved heat resistance. There was a strong desire for the emergence of a negative photoresist that could provide patterns.

Problems to be Solved by the Invention The present invention, in response to such demands, has developed a method using deep UV and excimer lasers, which are sensitive to high sensitivity and high resolution, and provide a resist pattern with good dry etching resistance. This was done with the aim of providing a high quality negative photoresist composition.

Means for Solving the Problems As a result of intensive research to develop a negative photoresist composition suitable for phosphorography using Deep Uv or excimer laser, the present inventors found that a specific phenol novolac resin and a specific The inventors have discovered that the objective can be achieved by combining it with an aromatic azide compound that absorbs light in the wavelength range of , and have completed the present invention based on this knowledge.

That is, the present invention relates to (A) the general formula (wherein R□ is an alkenyl group or an alkenyloxy group,
(R2 is a hydrogen atom, a hydroxyl group, an alkyl group, an alkenyl group, or an alkoxy group) A substituted phenol novolac resin consisting of a condensate of a phenol represented by the following formula and formaldehyde, and (B)
The present invention provides a negative photoresist composition containing an aromatic azide compound that absorbs light with a wavelength of 350 nm or less.

The present invention will be explained in detail below.

The phenol used as a raw material for the substituted phenol novolac resin as component (A) in the composition of the present invention has a substituent having a carbon-carbon double bond represented by the general formula (I), and Examples include 2-(1-propenyl)phenol, 2-(2-propenyl)phenol, 4-(1-propenyl)phenol, 4-(2-propenyl)phenol, 3-(2-propenyl)phenol,
7'lopenyl)-1,2-benzenediol, 4-(2
-propenyl)-1,2-benzenediol, 2-(2
-propenyl)-4-methylphenol, 2-(2-propenyl)-6-methylphenol, 4-α-methylvinylphenol, 2,6-di(propenyl)phenol, 2-methoxy-4-(1-propenyl ) phenol,
Examples include 2-methoxy-4-(2-propenyl)phenol.

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

Moreover, it is preferable to mix the above-mentioned general formula enol, cresol, etc. with these phenols. In this case, the blending amount is preferably in the range of 20 to 90% by weight relative to the phenol represented by the general formula (I), and if the blending amount exceeds 90% by weight, the heat resistance will decrease.
On the other hand, if it is less than 20% by weight, it is not preferable because the solubility in alkali is low.

In the composition of the present invention, a substituted phenol novolac resin obtained by condensing the above-mentioned phenols and formaldehyde by a conventional method is used as component (A).

The substituted phenolic novolak resin used in the present invention is preferably mixed with other novolak resins, such as phenol novolak resins or cresol novolak resins. In this case, the mixing amount thereof is preferably in the range of 20 to 90% by weight relative to the substituted phenol novolac resin. If the amount of other novolak resins exceeds this range, the heat resistance will be poor, and if the resin is not mixed, the solubility in alkali will be low, which is not preferable.

As the aromatic azide compound of component (B) in the composition of the present invention, any compound having a maximum absorption wavelength of 350 nm or less can be used, and specifically, 4, 4,
Examples include '-diazido diphenyl sulfite\4.4'-diazido diphenyl sulfone, 4,4'-diado diphenylmethane, polyvinyl azide benzoate, and polyvinyl azide formal. These may be used alone or in combination of two or more.

Regarding the blending ratio of the components (A) and (B) in the composition of the present invention, the amount of the aromatic azide compound (B) is 10 to 40 parts by weight per 100 parts by weight of the substituted phenol novolac resin (A). It is preferable to mix them in parts by weight. If the amount is less than 10 parts by weight, the sensitivity will be low, and if it exceeds 40 parts by weight, the azide compound will precipitate in the coating liquid when the composition is prepared into a coating liquid, resulting in poor stability. This is not preferable because it reduces the

The composition of the present invention is preferably used in the form of a solution by dissolving the substituted phenol novolak resin as component (A) and the aromatic azide compound as component (B) in a suitable solvent. Examples of this solvent include acetone, methyl ethyl ketone,
Ketones such as cyclohexanone: monomethyl ether, monoethyl ether, monoethyl ether, mono of ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol monoacetate Examples include polyhydric alcohols such as butyl ether or monophenyl ether, derivatives thereof, cyclic ethers such as nidioxane, and esters such as methyl acetate, ethyl acetate, and butyl acetate. These solvents may be used alone or in combination of two or more.

The negative photoresist compositions of the present invention may further contain compatible additives, such as additional resins, plasticizers, stabilizers or colorants to make the developed image more visible. It is possible to add some materials.

A preferred method for using the composition of the present invention is to first apply the negative photoresist coating solution of the present invention prepared as described above onto a substrate such as a silicon wafer using a spinner or the like, and dry it. After forming the photosensitive layer, it is exposed to light through a required mask using a Dθθp UV exposure device, an excimer laser exposure device, or the like. Next, this is developed using a developer such as an aqueous solution of tetramethylammonium hydroxide or choline having a weight ratio of 1.5 to 5 to obtain a resist pattern in which non-exposed areas are selectively dissolved and removed. Thereafter, by irradiating the entire surface of the resist pattern with ultraviolet light having a wavelength of 350 to 450 nm, a resist pattern with excellent heat resistance can be obtained.

Effects of the Invention The negative photoresist composition of the present invention is a combination of a substituted phenol novolac resin having a carbon-carbon double bond and an aromatic azide compound, and
Not only the azide group but also the carbon-carbon double bond is cross-linked by active light having the following wavelength, resulting in an excellent cross-sectional shape.
Moreover, since it is possible to provide a fine resist pattern with improved heat resistance, it is suitably used for manufacturing semiconductor integrated circuit elements such as VLSI.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 Substituted phenol novolac resin 85 obtained by adding 7 mol of formalin O to 1 ml of 2-(2-propenyl)phenol and condensing the mixture in a conventional manner using an oxalic acid catalyst.
parts by weight, 4,4'-diazide diphenyl sulfide 1
After dissolving 5 parts by weight in 400 parts by weight of ethylene glycol monoether acetate, this was dissolved in a pore size of 0.
．． A photoresist composition was prepared by filtration using a 2 μm membrane filter.

This photoresist composition was coated with a resist coater TR-40.
The resist was coated on a 4-inch silicon wafer using Model 00 (manufactured by Tara Shichisha) and prebaked at 85° C. for 30 minutes to form a resist layer with a dry thickness of 1.0 μm. Then, using a Deep IIV exposure device using a xenon-mercury lamp, 1 Deep UV was applied through the test chart mask.
After irradiation for 5 seconds, development was performed at 23° C. for 60 seconds with a 3.0% by weight aqueous solution of tetramethylammonium hydroxide, resulting in a line-and-space pattern with a vertical cross-section of 0.7 μm.

Then, a 100W low-pressure mercury lamp (8mW/c at 254nm) was applied to the entire surface of the resist pattern obtained by this development.
M2) was irradiated with Dθθp UV for 2 minutes.

The resist pattern thus obtained did not soften even when subjected to heat treatment at 250° C. for 30 minutes.

Examples 2 to 7, Comparative Examples 1 to 3 Except for replacing the substituted phenol novolac resin and aromatic azide compound in Example 1 with the components shown in the following table,
Resist layer turns were formed in the same manner as in Example 1, and the resolution and heat resistance of the resist pattern were examined. The results are shown in the table below.

Note 1) Heat resistance was determined by the presence or absence of blur when heated to 250°C.

2) The weight ratio of the mixture in the substituted phenol novolak resin is in parentheses.

Claims (1)

[Claims] 1 (A) General formula ▲ Numerical formulas, chemical formulas, tables, etc. A substituted phenol novolak resin consisting of a condensate of phenols and formaldehyde represented by
A negative photoresist composition comprising an aromatic azide compound that absorbs light with a wavelength of 350 nm or less.