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
2001-04-03
2003-06-17
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
C430S905000, C430S910000
Reexamination Certificate
active
06579659
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a chemical amplifying type positive resist composition used in the micro processing of a semiconductor.
In general, a lithography process using a resist composition has been adopted in the micro processing of a semiconductor. In lithography, the resolution can be improved with a decrease in wavelength of the exposure light in principle as expressed by Rayleigh's equation related to diffraction. 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 serially adopted as exposure light sources for lithography used in the manufacture of semiconductors. Thus, the wavelength has become shorter year by year. An ArF excimer laser having a wavelength of 193 nm is considered to be promising as the 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, as a resin in a resist for an ArF excimer laser lithography, an alternating copolymer consisting of polymeric units derived from alicyclic olefin and a polymeric unit derived from an unsaturated di-carboxylic acid anhydride (Proc. SPIE, Vol. 2724, pages 355-364 (1996) by T. I. Wallow et al), a polymer comprising polymeric units derived from alicyclic lactone (JP-A-2000-26446) and the like are known.
However, using such a conventional resin, balance among properties required for resist such as resolution, profile, sensitivity, dry-etching resistance and adhesion is insufficient, and further improvement has been desired.
An object of the present invention is to provide a positive resist composition of chemical amplification type which contains a resin component and an acid generating agent and is suitable for eximer laser lithography such as ArF laser lithography, KrF laser lithography and the like, wherein the composition is excellent in balance of properties such as resolution, profile, sensitivity, dry etching resistance, adhesion and the like.
The present inventors have previously found that adhesion to a substrate can be improved by using a resin having polymeric units of 2-alkyl-2-adamantyl (meth)acrylate, unsaturated dicarboxylic anhydride, alicyclic olefin and the like, or polymeric units of 2-alkyl-2-adamantyl (meth)acrylate, 3-hydroxy-1-adamantyl (meth)acrylate and the like, as a part of polymeric units in a resin constituting a chemical amplification type positive resist composition, and have suggested this finding (JP-A-11-305444 and 11-238542). Thereafter, the present inventors have further studied, and resultantly, found that a resist composition excellent in balance of properties such as resolution, profile, sensitivity, dry etching resistance, adhesion and the like can be obtained by using a resin having polymeric units such as an alicyclic lactone, unsaturated dicarboxylic anhydride, alicyclic olefin and the like, a resin having polymeric units such as an alicyclic lactone, 3-hydroxy-1-adamantyl (meth)acrylate and the like, or a resin having polymeric units such as an alicyclic lactone, (&agr;)&bgr;-(meth)acryloyloxy-&ggr;-butyrolactone and the like. Thus, the present invention was completed.
SUMMARY OF THE INVENTION
The present invention provides a practically excellent chemical amplification type positive resist composition comprising a resin which has the following polymeric units (A), (B) and (C), and is insoluble itself in an alkali, but becomes alkali-soluble by the action of an acid; and an acid generating agent.
(A): At least one polymeric unit of an alicyclic lactone selected from polymeric units represented by the following formulae (Ia) and (Ib);
wherein, each of R
1
and R
2
independently represents hydrogen or methyl, and n represents a number of 1 to 3:
(B): At least one polymeric unit selected from a polymeric unit represented by the following formula (II), a polymeric unit of a combination of a unit represented by the following formula (III) and a unit derived from unsaturated dicarboxylic acid anhydride selected from maleic anhydride and itaconic anhydride and a polymeric unit represented by the following formula (IV):
wherein, R
3
and R
7
represent hydrogen or methyl, R
4
represents hydrogen or hydroxyl group, each of R
5
and R
6
independently represents hydrogen, alkyl having 1 to 3 carbon atom, hydroxyalkyl having 1 to 3 carbon atoms, carboxyl, cyano or group —COOR
7
wherein R
7
is an alcohol residue, or R
5
and R
6
together form a carboxylic anhydride residue represented by —C(═O)OC(═O)—;
(C) A polymeric unit which becomes alkali-soluble by cleavage of a part of groups by the action of an acid.
The resist composition of the present invention comprises a resin having the above-mentioned polymeric units (A), (B) and (C). As the monomer used for driving polymeric units of alicyclic lactones represented by the formula (Ia) and (Ib). specifically, (meth)acrylates of alicyclic lactones having a hydroxyl groups describer below, mixtures thereof, and the like are exemplified. These esters can be produced, for example, by reacting the corresponding alicyclic lactone having a hydroxyl group and (meth)acrylic acids (e.g., JP-A 2000-26446).
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 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-hydroxylcyc
Miya Yoshiko
Takata Yoshiyuki
Uetani Yasunori
Yamada Airi
Ashton Rosemary
Birch & Stewart Kolasch & Birch, LLP
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