Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2000-05-31
2003-05-27
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S920000, C430S921000, C430S919000
Reexamination Certificate
active
06569596
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a negative working chemical amplification type resist composition which is used for forming: a resist pattern by irradiation of radiation such as ultra violet ray, electron beam or X-rays and by alkaline development, and for manufacturing semiconductor integrated circuits.
Negative working chemical amplification type resists comprising an alkali-soluble resin, a cross-linking agent and an acid generator are alkali-soluble as they are, but are changed to an alkali-insoluble state by cross-linking the alkali-soluble resin with the cross-linking agent through the post exposure bake (sometimes abbreviated as PEB) with the aid of an acid, working as a catalyst, generated from the acid generator by irradiation with a radiation. Therefore, these resists can form a negative image by irradiation with a radiation through a mask (so-called patterning exposure) and alkaline development. These negative working chemical amplification type resists have frequently been used in the production of integrated circuits because of their excellent resolution and sensitivity. As the recent increase in integration level of the integrated circuits, a further improvement in the resolution has been demanded.
The alkali-soluble resin which have been used in conventional known negative working chemical amplification type resists were novolak resins, polyvinylphenol, and polyvinylphenol compounds in which hydroxyl groups are partially alkyl etherified, as disclosed in JP-A-7-295220. A sufficient and satisfactory resolution for meeting the recent demand, however, could not be obtained by simply improving the alkali-soluble resin.
The purpose of the present invention is to provide negative working chemical amplification type resist compositions having an improved resolution. As the result of extensive studies for attaining such purpose, the present inventors have found the fact that the resolution can be further improved by comprising a certain specific compound together with an alkali-soluble resin, a cross-linking agent and an acid generator. The present invention has been completed based on such fact.
SUMMARY OF THE INVENTION
The present invention provides a negative working chemical amplification type resist composition comprising an alkali-soluble resin; a cross-linking agent; a N-substituted succinimide compound represented by the owing formula (I):
wherein R represents an unsubstituted or substituted alkyl, an alicyclic hydrocarbon residue, an aryl or a camphor group, and;
an acid generator other than the above N-substituted succinimide compound.
DETAILED DESCRIPTION OF THE INVENTION
The alkali-soluble resin and the cross-linking agent in the present invention may be those commonly used in this field. As the alkali-soluble resin, a novolak resin, polyvinylphenol or a polyvinylphenol compound in which hydroxyl groups are partially alkyl etherified is commonly used.
A novolac resin can usually be obtained by condensing a phenol compound and an aldehyde in the presence of an acid catalyst.
Examples of the phenol compound used in the preparation of the novolac resin include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-tert-butyl-4-methylphenol, 2-tert-butyl-5-methylphenol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 2-methoxyphenol, 3-methoxyphenol, 4-methoxyphenol, 2,3-dimethoxyphenol, 2,5-dimethoxyphenol, 3,5-dimethoxyphenol, 2-methoxyresorcinol, 4-tert-butylcatechol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 2,5-diethylphenol, 3,5-diethylphenol, 2,3,5-triethylphenol, 2-naphthol, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene and a polyhydroxytriphenylmethane compound obtainable by condensation of xylenol and hydroxybenzaldehyde. These phenol compounds can be used singly or in combination of two or more.
Examples of the aldehyde used in the preparation of the novolac resin include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butylaldehyde, iso-butylaldehyde, pivalaldehyde, n-hexylaldehyde, acrolein and crotonaldehyde; alicyclic aldehydes such as cyclohexanealdehyde, cyclopentanealdehyde, furfural and furylacrolein; aromatic aldehydes such as benzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde, 3,4-dimethylbenzaldehyde, 3,5-dimethylbenzaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-anisaldehyde, m-anisaldehyde, p-anisaldehyde and vanillin; and aromatic-aliphatic aldehydes such as phenylacetaldehyde and cinnamaldehyde. These aldehydes can be used singly or in combination of two or more. Among these aldehydes, formaldehyde is preferably used because of easy availability in the industry.
Examples of the acid catalyst used for condensation of the phenol compound with the aldehyde compound include inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid and phosphoric acid; organic acids such as formic acid, acetic acid, oxalic acid, trichloroacetic acid and p-toluenesulfonic acid; and bivalent metal salts such as zinc acetate, zinc chloride and magnesium acetate. These acid catalysts can be used singly or in combination of two or more. The condensation reaction can be carried out according to the usual manner, for example, at a temperature within a range of 60 to 120° C. for 2 to 30 hours.
It is preferred for improving the resolution of the resist that a novolak resin having a weight average molecular weight of 900 or less is contained as a part of the alkali-soluble resin. The weight average molecular weight herein refers to a value measured by gel permeation chromatography (GPC) using polystyrene as the standard. This is also applied to other weight average molecular weight referred to below in this specification. These low molecular weight novolak resin oligomer can also be produced by condensing a phenol compound as described above and an aldehyde in the presence of an acid catalyst according to the conventional method. In this reaction, reaction conditions for obtaining low molecular weight product should be adopted. For example, amount of acid should be smaller, such as about 0.001 to 0.01 times the mole of the phenol compound as the raw material, and reaction period should be shorter such as about 1 to 5 hours.
When the low molecular weight novolak resin oligomer is used as a part of the alkali-soluble resin, the rest of the alkali-soluble resin is preferably a resin having a greater weight average molecular weight than said resin. For example, a resin having a weight average molecular weight of 2,000 or more is preferable. Particularly, co-use of a novolak resin mainly comprising a higher molecular weight fraction is preferred for improving the resolution. Specifically, it is preferred that a pattern area of the resin corresponding to polymers having a, molecular weight of 1,000 or less is 25% or less, more preferably 20% or less, of the total pattern area except for the area of the unreacted phenol compound as the raw material. The pattern area herein refers to an area measured by GPC with an UV detector at 254 nm. The molecular weight herein refers to a value measured using polystyrene as the standard, as in the weight average molecular weight described above. The novolak resin mainly comprising a higher molecular weight fraction as described above can be produced, for example, by applying a fractionation to a novolak resin obtained by the condensation reaction. For carrying out the fractionation, adoptable methods include: a method in which a novolak resin is dissolved in a good solvent, and then the solution is poured into water for precipitating the higher molecular weight fraction; and a method in which said solution is mixed with a poor solvent such as pentane, hexane or heptane, and the lower layer containing mainly the higher molecular weight fraction is separated. Examples of
Inoue Hiroki
Uetani Yasunori
Yamada Airi
Ashton Rosemary
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Chemical Company Limited
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