JPH0429146A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To improve a resolution without impairing heat resistance by incorporating a solvent essentially consisting of specific 3-octanone into the above resist. CONSTITUTION:The 3-octanone expressed by formula I is used as the solvent. The positive type resist compsn. contains a quinone diazide compd. and alkaline- soluble resin. While the amt. of the solvent to be used is not particularly limited as far as the coating to form the coating film of the uniform quality free from pinholes and unequal coating on a wafer is possible, the resist compsn. is usually prepd. to the concn. at which the solid content, i.e., a radiation sensitive compd. and resin are incorporated therein in a 3 to 50wt.% range; in addition, the ratio of the 3-octaone to the total solvent amt. is 50 to 100wt.%. The resist having the excellent heat resistance and resolution is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a novel positive resist composition.

<Prior Art> A radiation-sensitive resist composition containing a compound having a quinonediazide group changes from an alkali-insoluble state to an alkali-soluble state by decomposing the quinonediazide group and producing a carboxyl group by irradiation with light of 500 nm or less. Utilizing this, a resist composition containing a compound having a quinonediazide group is used as a positive resist. This positive resist is characterized by extremely high resolution and is used in the production of integrated circuits such as ICJP LSI.

In recent years, integrated circuits have become increasingly finer due to higher integration, and submicron pattern formation is now required.

One way to improve the resolution of the resist is to lower the molecular weight of the alkali-soluble resin, but this method lowers the heat resistance.

In general, resolution and heat resistance tend to contradict each other, and attempts to improve one result in the inconvenience of worsening the other.

<Problems to be Solved by the Invention> An object of the present invention is to provide a positive resist composition with excellent resolution without impairing heat resistance.

Specific Means for Solving the Problem> As a result of intensive studies aimed at providing a resist with excellent resolution without impairing heat resistance, the present inventors found that the resist expressed by the following formula (I) discovered that these objectives could be achieved by using 3-octanone as a solvent,
This led to the present invention.

The positive resist composition of the present invention contains a quinonediazide compound and an alkali-soluble resin. The quinonediazide compound, which is a radiation-sensitive compound used in the positive resist composition, is not particularly limited, but includes, for example, 1.
2-benzoquinonediazide-4-sulfonic acid ester,
Examples include 1.2-naphthoquinonediazide-4-sulfonic acid ester and 12-naphthoquinonediazide-5-sulfonic acid ester. These esters can be obtained by a known method, for example, by condensing 1,2-naphthoquinonediazide sulfonic acid or benzoquinonediazide sulfonic acid with a compound having a hydroquine group in the presence of a weak alkali.

The alkali-soluble resin used in the composition of the present invention is not particularly limited, and examples thereof include polyvinylphenol, novolak resin, and the like. Novolac resins include, for example, phenol, 0-cresol, m-cresol, p-talesonope 2,5-xylenol, 3,5
-xylenol, 3.4-xylenol, 2,3.5-
) Limethylphenol, 4-t-butylphenol, 2
-t-butylphenol, 3-t-butylphenol,
3-ethylphenol, 2-ethylphenol 4-
Ethylphenol, 3-methyl-6-t-butylphenol, 4-methyl-2-t-butylphenol, 2-naphthol, 1.3-dihydroxynaphthalene, 1.7-
Phenols such as dihydroxynaphthalene and 1,5-dihydroxynaphthalene alone or in combination of two or more,
Examples include resins condensed with aldehydes by conventional methods.

The weight ratio of these radiation-sensitive compounds to the alkali-soluble resin is preferably in the range of 1:1 to 1.

The amount of solvent used in the present invention is uniform on the wafer,
There is no particular restriction as long as it is possible to form a coating film without pinholes or uneven coating, but usually the resist composition is adjusted to a concentration such that the solid content, that is, the radiation-sensitive compound and resin is in the range of 3 to 50% by weight. do. Further, the amount of 3-octanone based on the total amount of solvent is preferably 50 to 100% by weight.

The composition of the present invention may contain other solvents as long as the effects of the present invention are not impaired.

The compositions of the present invention may also contain, for example, sensitizers, other additive resins, surfactants, stabilizers, or dyes to make the formed image more visible, as well as other additives commonly used in the art. Various additives can be added.

<Effects of the Invention> The positive resist composition of the present invention has excellent heat resistance and resolution.

<Examples> The present invention will be specifically explained below using Examples, but the present invention is not limited thereto.

Examples and Comparative Examples A resist solution was prepared by dissolving a novolac resin and a quinonediazide compound in 50 parts of a solvent with the composition shown in Table 1.

A resist solution was prepared by filtering each of these compositions through a 0.2 μm Teflon filter. This was coated to a thickness of 1.3 μm using a spin coater on a silicon wafer that had been cleaned by a conventional method.

The silicone wafer was then baked on a hot plate at 100° C. for 60 seconds. Then add 436 to this wafer.
Exposure was carried out using a reduction projection exposure machine having an exposure wavelength of 1 m (g-line) using a Kon Co., Ltd. NSR1505G3CNA=0.42) while changing the exposure amount stepwise. A positive pattern was obtained by developing this for 1 minute with Sumitomo Chemical developer 5OPD.

The resolution was evaluated using an SEM (scanning electron microscope) to determine the dimensions of the line and space pattern that can be separated without film loss at an exposure dose that makes the 0.8 μm line and space pattern 1:1.

The heat resistance of the resist was determined by heating the wafer after the resist pattern was formed on a direct hot plate at a predetermined temperature for 3 minutes, and then observing the presence or absence of thermal deformation of the 3 μm line and space pattern using SEM.

The results are shown in Table 1.

1) Novolac resin A novolak with a weight average molecular weight of 6000 (in terms of polystyrene) obtained by reacting using a nitrogen acid catalyst at a molar ratio of macresol/paracresol = 4/6 and formalin/cresol = 0.8/1. resin.

2) Quinonediazide Compound A A condensation reaction product of naphthoquinone-(1,2)-diazide-(2)5-sulfonic acid chloride and a compound of the following formula. (Reaction molar ratio 2.5:1) CH, C113 Quinonediazide compound B Naphthoquinone = (1,2)-diazide-(2) condensation reaction product of 5-sulfonic acid chloride and 2.3,4,4°tetrahydroxybenzophenone .

(Reaction molar ratio 2.7:1) 3) Heat resistance Temperature at which a 3 μm line and space pattern starts to undergo thermal deformation.

Claims (2)

[Claims] (1) A positive resist composition characterized by containing a solvent containing 3-octanone represented by the following formula (I) as a main component. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (2) The positive resist composition according to claim 1, wherein the quinonediazide compound and the alkali-soluble resin are dissolved in a solvent.