JPH04151156A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To avert the film thinning in unexposed parts so that rectangular shapes are formed and to allow patterning with a high resolution and high accuracy by incorporating a compd. which generates an acid or base when irradiated with radiations and a compd. which is soluble in alkalis and is dislocated and hardened when heated into the above compsn. CONSTITUTION:The compd. which generates the acid or base when irradiated with the radiations and the compd. which is soluble in alkalis in the presence of the acid or base and is dislocated and hardened when heated are incorporated into the above compsn. The acid or base is generated in the exposed parts and the exposed parts are dispersed and converted to the compsn. soluble in a developer when this photosensitive resin compsn. is irradiated with radiations. The entire part is then heat treated, by which a curing reaction is induced in the unexposed parts and a crosslinked structure is generated. The formation of the alkali-soluble compd. is thereby induced in the exposed parts and the insolubilization by the crosslinking of the high polymer in the unexposed parts. A difference in dissolution in the developer is thus generated and eventually, the pattern formation is enabled. Since the reaction entailing the crosslinked structure takes place in the unexposed parts at this time, the dissolution into the developer is prevented. The generation of the film thinning is prevented in this way and the patterns having the rectangular shapes are obtd. with the high resolution and high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive resin composition used, for example, in forming highly accurate fine patterns.

[Prior Art] Patterning for microfabrication of semiconductor elements and the like is performed by photolithography. In this case, light.

Resists that are sensitive to actinic rays such as electron beams are used. Conventionally, such materials have been used as resists, such as materials that decompose when irradiated with actinic rays, or compounds that harden when irradiated with radiation. however,
In these compounds, only the achievable type of reaction occurs, and the efficiency is extremely low because it reacts with the energy irradiated.
As a result, no significant improvement in sensitivity can be expected.

In recent years, in order to solve these problems, resists based on the idea of a chemical amplification mechanism have been studied. This is done using the acid that is generated when exposed to light as a catalyst.

This is a method in which the reaction is accelerated thermally instead of using light. In this method, the amount of light irradiation is sufficient to generate a catalytic amount of acid, so high sensitivity can be achieved at the 11th time.

On the other hand, the properties required of resist materials have become increasingly sophisticated, and it is no longer possible to satisfy all the properties by simply composing a resist with a single polymer compound.

The idea of a multicomponent resist that uses several materials in combination to share each characteristic was proposed. As a resist that takes these two ideas into consideration, for example, the publication (Polyme
r Engineering Science Volume 26 No. 1
101, published in 1986), a resist consisting of a novolac resin, a melamine resin, and an acid generator, and a resist consisting of a novolac resin, an acetal compound, and an acid generator, described in JP-A-1-10640, etc. is proposed.

[Problems to be Solved by the Invention] However, the former of the above-mentioned conventional examples has negative photosensitivity, and swelling and the like occur due to the developer.

In the latter case, where no improvement in resolution can be expected, swelling can be avoided because it is a positive type, but unexposed areas will dissolve to some extent.
Film peeling occurs during development, resulting in problems such as lower resolution and lower pattern accuracy.

This invention was made to solve this problem, and when applied to a resist with the same high sensitivity to radiation as the conventional one, the exposed area will dissolve in the developer, and the unexposed area will be cured and developed. The object of the present invention is to obtain a photosensitive resin composition that can prevent dissolution in a liquid, can avoid film sagging in unexposed areas, has a rectangular shape, and can be patterned with high resolution and high precision.

[! [Means for Solving IllIM] The photosensitive resin composition of the present invention contains a compound that generates an acid or base upon irradiation with radiation, and a compound that becomes alkali-soluble in the presence of an acid or base and undergoes rearrangement and hardening upon heating. It contains.

[Function] When the photosensitive resin composition of the example of this invention is irradiated with radiation, an acid or base is generated in the exposed area, and the exposed area is decomposed by this acid or base, making the composition soluble in a developer. Next, by heat-treating the whole, a curing reaction occurs in the unexposed area, and due to the reaction of 0 or more that forms a crosslinked structure, the formation of an alkali-soluble compound in the exposed area.
In the unexposed area, insolubilization occurs due to polymer crosslinking, resulting in a difference in solubility in the developer, and as a result, pattern formation becomes possible. At this time, since a reaction involving a crosslinked structure occurs in the unexposed area, dissolution in the developer is prevented, so that film burrs are prevented from occurring and a rectangular pattern is obtained.

[Example] The photosensitive resin composition of the example of this invention was - numerically (
It consists of a) an alkali-soluble polymer compound, (b) a compound that decomposes in the presence of an acid or base, and (C) a compound that generates an acid or base when irradiated with radiation, but (a)
) and (c) may be combined with the compound (b).

Examples of compounds related to this invention that decompose in the presence of an acid or base to become alkali-soluble and undergo rearrangement and harden when heated include carboxylic acid azides and sulfonic acid azides. It can be easily synthesized by reacting sodium azide or sulfonic acid chloride with sodium azide.

Examples of acid chlorides include: isophthalic acid dichloride, terephthalic acid dichloride, benzenetricarboxylic acid a-ride, benzophenone dicarboxylic acid chloride, diphenyl ether dicarboxylic acid chloride, polyphenylmethane dicarboxylic acid chloride, naphthalenedicarboxylic acid chloride, benzene disulfonic acid Examples include chloride, benzene trisulfonic acid chloride, diphenyl ether disulfonic acid chloride, polyphenylmethane disulfonic acid chloride, hexamethylene dicarboxylic acid chloride, cyclohexyldicarboxylic acid chloride, butanetetracarboxylic acid chloride, and the like.

Examples of compounds that generate acids upon irradiation with radiation according to the present invention include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroarsinate, and triphenylsulfonium hexafluoroborate. Fluorophosphate, triphenyl sulfonium trifluorosulfonate, diphenyl iodonium tetrafluoroborate, diphenyl iodonium hexafluoroantimonate, diphenyl iodonium hexafluoroarsinate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium trifluoro Onium salts such as sulfonates, 2.4,
6. -) Lis(trichloromethyl)triazine, 2allyl-4,6-bis(trichloromethyl)triazine.

α,α,α,-tribromomethyl-phenylsulfone,
α,α,α,α′,α,α,-hexachloroxylylene, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)-1.1,1,3,3,3-hexafluoro propane, 1,1.1-)lis(3,5-dibrome-
halogen-containing compounds such as 4-hydroxyphenyl)ethane, 2-nitropenzyl trilate, 2,6-sinitropenzyl tosylate, and 2,4-dinitropenzyl tolate. Examples include sulfonic acid esters such as methylsulfonic acid 2-nitrobenzyl ester, acetic acid 2-nitrobenzyl ester, and p-nitrobenzyl-9,10-dimethoxyanthracene-2-sulfonate.

Examples of the compound that generates a base upon irradiation with radiation according to the present invention include 1,1.1-)ri-phenylmethanol, 1,1.1-)-ri(methoxyphenyl)methanol, 1,1. 1-1-ly(methylphenyl)
Methanol, 1.1. i tritrophenyl) methanol, 1,1. i) Riphenylcyanomethane, I, l,
1-) Su(methoxyphenyl)cyanomethane, 1,1
．． Examples include 1-tri(methylphenyl)cyanomethane.

Further, when an alkali-soluble polymer compound is used in the photosensitive resin composition of the embodiment of the present invention, it is necessary that it has a structure with excellent dry etching resistance, and examples of materials suitable for this purpose include, for example.

Examples include phenol-formaldehyde resins such as phenol novolac resin, cresol novolac resin, and naphthol novolac resin, polyvinylphenol resin, and copolymers of vinylphenol and acrylic thread or styrene monomer.

Note that the radiation referred to here refers to visible light, ultraviolet rays, far ultraviolet rays, electron beams, X-rays, and the like.

An example of forming a pattern using a photosensitive resin composition according to an embodiment of the present invention will be described below in detail. First, compounds that generate acids or bases when irradiated with radiation,
a or a compound that decomposes in the presence of a base to become alkali-soluble and is rearranged and hardened by heating, a resist made of the photosensitive resin composition of the embodiment of the present invention is applied to a substrate such as a silicone wafer, After heating to remove the solvent, radiation is irradiated (or drawn in the case of electron beam) through a mask with a predetermined pattern.Next, in order to harden the unexposed areas, heating is performed at 60 to 150 °C. Good patterning can be achieved by performing the following steps: Further, the pattern forming method using the photosensitive resin composition of the present invention described above can be used as a microfabrication method that requires fine patterning of semiconductor elements, printed wiring boards, and the like.

Next, the present invention will be explained using specific examples, but is not limited thereto.

Example I 13g (0.2 liters) of sodium azide at 200w
The mixture was dissolved in L of water and cooled to 5°C. Terephthalic acid chloride 17p; (0.1 liter) was added little by little into this solution, and after all the addition, it was stirred for 1 hour, and then the W1 was kept pressed for 4 hours at room temperature. After the 0 reaction, the precipitated crystals were collected. After drying under reduced pressure, it was recrystallized from methanol to synthesize terephthalic acid azide.

Next, 5cresol novolak resin (Mn=6000)7
g, 3 g of terephthalic acid azide, and 0.3 g of diphenyliodonium tetrafluoroborate were dissolved in 25 g of cyclohexanone, and passed through a 0.2 micron filter to obtain a solution containing the photosensitive resin compound of one embodiment of the present invention. A resist solution was prepared.

This resist solution was applied onto a silicon wafer and
The wafer was pre-cured in an oven for 10 minutes at
pLIV light was irradiated. After irradiation, heat on a hot plate at 110°C for 2 minutes, return to room temperature, and then soak in 2% tetramethylammonium hydroxide aqueous solution for 2 minutes.
n immersion and development.

Through this series of operations, a good pattern with lines and spaces of 0.35 microns was obtained.

Examples 2 to 10 The compounds shown in Table 1 were synthesized in the same manner as in Example 1, and photosensitivity 17 of other examples of this invention was synthesized in the same manner as in Example 1.
Next, a resist solution containing an M fat compound was prepared, and a pattern was formed by the same operation as in Example 1.

As shown in Table 2, both had high sensitivity and good rectangular patterns of 0.35 microns were obtained.

[Effects of the Invention] As explained above, the present invention provides compounds that contain compounds that generate acids or bases when irradiated with radiation, and compounds that become alkali-soluble in the presence of acids or bases and undergo rearrangement and harden when heated. By using it, when applied to a resist with high sensitivity to radiation comparable to conventional ones,
It is possible to obtain a photosensitive resin composition that can avoid film deterioration in unexposed areas, has a rectangular shape, and can be patterned with high resolution and precision, and can be effectively used, for example, in the formation of ultrafine patterns for semiconductors, etc. It is.

Claims (1)

[Claims] A photosensitive resin composition containing a compound that generates a base upon irradiation with radiation, and a compound that becomes alkali-soluble in the presence of an acid or base, and undergoes rearrangement and hardening upon heating.