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
2001-01-22
2002-11-05
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, C430S905000, C430S326000
Reexamination Certificate
active
06475699
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 wavelength of 193 nm 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 action of 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.
However, conventionally known resins have a problem that peeling off of a pattern at development tends to occur due to insufficient adhesion, especially when the polarity is insufficient. Excellent dry etching resistance is also desired in resist since the resist film of resist pattern formed in lithography functions as a protection film at the dry etching process in production of integrated circuit.
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 adhesion to a substrate and dry-etching resistance while exhibiting various excellent resist performance characteristics such as sensitivity and resolution.
The inventors of the present invention have discovered the fact that a chemical amplifying type positive resist composition comprises a resin component having a polymeric unit of a specific structure is excellent in adhesion to a substrate and dry-etching resistance as well as in balance of various resist performance characteristics such as sensitivity and resolution. The present invention has been completed based on this discovery.
SUMMARY OF THE INVENTION
The present invention provides a chemically amplified positive resist composition comprising a resin (X) which, per se, is insoluble or slightly soluble in alkali but becomes soluble in alkali when subjected to an action of acid, and has
(a) a polymeric unit, derived from 1-adamantyl-1-alkylalkyl (meth)acrylate, represented by the following formula (I):
wherein R
1
represents hydrogen or methyl, R
2
and R
3
each independently represent alkyl having 1 to 4 carbon atoms, and R
4
and R
5
each independently represent hydrogen, hydroxyl or alkyl,
(b) polymeric unit, derived from alicyclic olefin, such as norbornene, represented by the following formula (II):
wherein R
6
and R
7
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
8
, wherein R
8
represents an alcohol residue,
or R
6
and R
7
together form a carboxylic acid anhydride residue represented by —C(═O)OC(═O)—, and
(c) 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
The polymeric unit derived from unsaturated dicarboxylic acid anhydride selected from maleic anhydride and itaconic anhydride is represented by the following formula (III) or (IV):
Although use of an alternating copolymer of norbornene and maleic 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., the resin comprised in the resist composition of the present invention further has the polymeric unit represented by the formula (I), which has a bulky acid cleavable. By the combination of the polymeric unit represented by the formula (I) with the polymeric units represented by the formulae (II) and (III) or (IV), adhesion to a substrate, dry-etching resistance, sensitivity and resolution can be improved.
In the formula (I), R
1
is hydrogen or alkyl. When R
1
is hydrogen, adhesion to a substrate and dry-etching resistance can be improved particularly. R
2
and R
3
each independently represent alkyl having 1 to 4 carbon atoms. It is usually advantageous that the alkyl represented by R
2
or R
3
is straight chain, although the alkyl may be branched. Specific examples of the alkyl represented by R
2
or R
3
include methyl, ethyl, propyl, isopropyl and butyl. R
4
and R
5
each independently represent hydrogen, hydroxyl or alkyl, and the group represented by R
4
or R
5
may be substituted at any positions on the adamantyl ring. The alkyl represented by R
4
or R
5
may have about 1 to 4 carbon atoms. The adamantyl ring may bond to the carbon linking R
2
and R
3
in the formula (I) at either 1-position or 2-position. Usually, 1-adamantyl is preferred.
Examples of monomers used for deriving the polymeric unit of formula (I) include
1-(1-adamantyl)-1-methylethyl acrylate,
1-(1-adamantyl)-1-methylethyl methacrylate,
1-(1-adamantyl)-1-ethylpropyl acrylate,
1-(3-hydroxyl-1-adamantyl)-1-methylethyl acrylate, and
1-(3-methyl-1-adamantyl)-1-methylethyl acrylate.
R
6
and R
7
in the formula (II) 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
8
, wherein R
8
represents an alcohol residue. Alternatively, R
6
and R
7
may together form a carboxylic acid anhydride residue represented by —C(═O)OC(═O)—. Examples of the alkyl represented by R
6
and R
7
include methyl, ethyl and propyl. Examples of the hydroxyalkyl represented by R
6
and R
7
include hydroxymethyl and 2-hydroxyethyl. Examples of the alcohol residue represented by R
8
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
8
, represented by R
6
and R
7
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.
The resin (X) comprised in the resist composition of the present invention may optionally has another polymeric unit in addition to a polymeric unit represented by the formula (I), a polymeric unit represented by the formula (II) and a polymeric unit represented by the formula (III) or (IV). As the optional polymeric unit, a unit which has no aromatic ring, but has a cyclic structure such as alicyclic ring, lactone ring or a cyclic acid anhydride residue. As the alicyclic
Kim Seong-Hyeon
Takata Yoshiyuki
Uetani Yasunori
LandOfFree
Chemically amplified positive resist composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chemically amplified positive resist composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemically amplified positive resist composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2990388