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
2001-02-26
2002-12-17
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
C430S910000
Reexamination Certificate
active
06495307
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a chemical amplifying type positive resist composition used in the minute processing of a semiconductor.
In general, a lithography process using a resist composition has been adopted in the minute processing of a semiconductor. In lithography, the resolution can be improved with a decrease in wavelength of exposure light in principle as expressed by the equation of Rayleigh's diffraction limited. A g-line with a wavelength of 436 nm, an i-line with a wavelength of 365 nm, and a KrF excimer laser with a wavelength of 248 nm have been adopted as exposure light sources for lithography used in the manufacture of a semiconductor. Thus, the wavelength has become shorter year by year. An ArF excimer laser having a wave length of 193nm is considered to be promising as a next-generation exposure light source.
A lens used in an ArF excimer laser exposure machine or an exposure machine using a light -source of shorter wave-length has a shorter lifetime as compared with lenses for conventional exposure light sources. Accordingly, the shorter time required for exposure to ArF excimer laser light is desirable. For this reason, it is necessary to enhance the sensitivity of a resist. Consequently, there has been used a so-called chemical amplifying type resist, which utilizes the catalytic action of an acid generated due to exposure, and contains a resin having a group cleavable by the acid.
It is known that, desirably, resins used in a resist for ArF excimer laser exposure have no aromatic ring in order to ensure the transmittance of the resist, but have an alicyclic ring in place of an aromatic ring in order to impart a dry etching resistance thereto. Various kinds of resins such as those described in Journal of Photopolymer Science and Technology, Vol. 9, No. 3, pages 387-398 (1996) by D. C. Hofer, are heretofore known as such resins. Also, use of an alternating copolymer consisting of polymeric units derived from alicyclic olefin and a polymeric unit derived from unsaturated di-carboxylic acid anhydride in a resist for an ArF excimer laser lithography is described in Proc. SPIE, Vol. 2724, pages 355-364 (1996) by T. I. Wallow et al.
However, using such a conventional resin, peeling off of the pattern is liable to occur on the developing process due to insufficient adhesion, particularly when its polarity is insufficient.
An object of the present invention is to provide a chemically amplified positive resist composition containing a resin component and an acid generating agent which is suitable for use in excimer laser lithography utilizing ArF, KrF or the like, and is satisfactory in various excellent resist performance characteristics such as sensitivity and resolution and, particularly, is excellent in adhesion to a substrate.
The inventors of the present invention have found that adhesion to a substrate is improved by using a resin having a polymeric unit derived from 2-alkyl-2-adamantyl-(meth)acrylate, a polymeric unit derived from unsaturated di-carboxylic acid anhydride, a polymeric unit derived from alicyclic olefin and the like as a part of the polymeric units in the resin composing a chemical amplifying type positive resist composition, and filed a patent application (JP-A-11-305444). They have conducted further studies and, as a result, have found that a specific resin having a polymeric unit derived from 3-hydroxy-1-adamantyl-(meth)acrylate, in addition to the above mentioned polymeric units, is more effective for improving adhesion to a substrate. The present invention was thus completed.
SUMMARY OF THE INVENTION
The present invention provides a chemically amplified positive resist composition comprising a resin (X) which, per se, is insoluble in alkali but becomes soluble in alkali when subjected to an action of acid, and has
(a) a polymeric unit, derived from 2-alkyl-2-adamantyl (meth)acrylate, represented by the formula(I),
(b) a polymeric unit, derived from 3-hydroxy-1-adamantyl (meth)acrylate, represented by the formula(II),
(c) a polymeric unit, derived from an alicyclic olefin, represented by the formula(III):
wherein R
1
and R
3
each independently represent hydrogen or methyl, R
2
represents alkyl, R
4
represents hydrogen or hydroxyl, and R
5
and R
6
each independently represent hydrogen, alkyl having 1 to 3 carbon atoms, hydroxyalkyl having 1 to 3 carbon atoms, carboxyl, cyano or a group represented by —COOR
7
, wherein R
7
represents an alcohol residue, or R
5
and R
6
together form a carboxylic acid anhydride residue represented by —C(═O)OC(═O)—, and
(d) a polymeric unit derived from unsaturated dicarboxylic acid anhydride selected from maleic anhydride and itaconic anhydride; and
an acid generating agent (Y).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
R
1
in the formula (I) and R
3
in the formula (II) is hydrogen or alkyl. It is preferred that at least one of R
1
and R
3
is hydrogen, since resin (X) having a polymeric unit derived acrylate exhibits more remarkable improving effects of adhesion to a substrate and dry-etching resistance than the resin not having a polymeric unit derived acrylate. R
4
represents alkyl having 1 to 4 carbon atoms. It is usually advantageous that the alkyl represented by R
4
is straight chain, although the alkyl may be branched. Specific examples of the alkyl include methyl, ethyl, propyl, isopropyl and butyl. Particularly, ethyl is preferred considering balance of sensitivity and heat resistance.
Examples of monomers used for deriving the polymeric unit of formula (I) include 2-methyl-2-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-ethyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl methacrylate and 2-n-butyl-2-adamantyl methacrylate. These monomers can be produced, for example, by reacting corresponding 2-methyl-2-adamantanols and (meth)acrylic acids.
Examples of monomers used for deriving the polymeric unit of formula (II) include 3-hydroxy-1-adamantyl acrylate, 3-hydroxy-1-adamantyl methacrylate, 3,5-dihydroxy-1-adamantyl acrylate and 3,5-dihydroxy-1-adamantyl methacrylate. These monomers can be produced, for example, by reacting corresponding hydroxyl adamantans and (meth)acrylic acids (JP-A-63-33350).
R
5
and R
6
in the formula(III) each independently represent hydrogen, alkyl having 1 to 3 carbon atoms, hydroxyalkyl having 1 to 3 carbon atoms, carboxyl, cyano or a carboxylate residue represented by —COOR
7
, wherein R
7
represents an alcohol residue. Alternatively, R
5
and R
6
may together form a carboxylic acid anhydride residue represented by —C(═O)OC(═O)—. Examples of the alkyl represented by R
5
or R
6
include methyl, ethyl and propyl. Examples of the hydroxyalkyl represented by R
5
and R
6
include hydroxymethyl and 2-hydroxyethyl. Examples of the alcohol residue represented by R
7
include unsubstituted or substituted alkyl having about 1 to 8 carbon atoms and 2-oxoxolane-3- or -4-yl. Examples of the substituents of the substituted alkyl include hydroxyl and an alicyclic hydrocarbon residue. Specific examples of the carboxylate residue, —COOR
7
, represented by R
5
and R
6
include methoxycarbonyl, ethoxycarbonyl, 2-hydroxyethoxycarbonyl, tert-butoxycarbonyl, 2-oxoxolane-3-yloxycarbonyl, 2-oxoxolane-4-yloxycarbonyl, 1,1,2-trimethylpropoxycarbonyl, 1-cyclohexyl-1-methylethoxycarbonyl, 1-(4-methylcyclohexyl)-1-methylethoxycarbonyl, and 1-(1-adamantyl)-1-methylethoxycarbonyl.
Examples of monomers used for deriving the polymeric unit of formula (III) include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene-2-carboxylic acid, methyl 5-norbornene-2-carboxylate, t-butyl 5-norbornene-2-carboxylate, 1-cyclohexyl-1-methylethyl 5-norbornene-2-carboxylate, 1-(4-methylcyclohexyl)-1-methylethyl 5-norbornene-2-carboxylate, 1-(4-hydroxylcyclohexyl)-1-methylethyl 5-norbornene-2-carboxylate, 1-methyl-1-(4-oxocyclohexyl)ethyl 5-norbornene-2-carboxylate, 1-(1-adamantyl)-1-methylethyl 5-norbornene-2-carboxylate, 1-methylcyclohexyl 5-norbornene-2-carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-
Fujishima Hiroaki
Takata Yoshiyuki
Uetani Yasunori
Ashton Rosemary
Birch & Stewart Kolasch & Birch, LLP
Sumitomo Chemical Company Limited
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