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
2001-02-01
2003-09-23
Baxter, Janet (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
C430S281100, C430S326000, C430S910000, C430S927000
Reexamination Certificate
active
06623907
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a positive-tone or negative-tone radiation-sensitive resin composition suitable as a resist for ultra-microprocessing using various types of radiation such as ultraviolet radiation, deep ultraviolet radiation, X-rays, and charged particle rays.
2. Description of Background Art
In the field of microfabrication exemplified by the manufacture of an integrated circuit device, development of a lithographic process capable of reproducing microfabrication with a line-width precision of 0.5 &mgr;m or less has been pursued in recent years to achieve higher integration. To ensure microfabrication in the order of 0.5 &mgr;m or less, a resist which can excellently reproduce patterns with a 0.5 &mgr;m or less line-width has been required. However, it is difficult to produce such a minute pattern at high precision by conventional methods using visible light (wavelength: 800-400 nm) or near ultraviolet light (wavelength: 400-300 nm). Because of this, the use of radiation with a shorter wavelength (wavelength: less than 300 nm) has been studied.
As examples of such short wavelength radiation, a bright line spectrum of a mercury lamp (wavelength: 254 nm), far ultraviolet rays typified by a KrF excimer laser (wavelength: 248 nm) and an ArF excimer laser (wavelength: 193 nm), X-rays such as synchrotron radiation, and charged particles such as electron beams can be given. Of these, lithography using an excimer laser is regarded as promising due to high output and high efficiency. Lithography using an excimer laser requires a resist which can reproduce fine patterns with a 0.5 &mgr;m or less line-width at high sensitivity and high resolution.
As a resist applicable to far ultraviolet rays such as an excimer laser, a chemically-amplified resist comprising a photoacid generator of which the sensitivity is improved by the catalytic action of an acid formed by the photoacid generator upon irradiation with radioactive rays (hereinafter referred to as “exposure”) has been proposed.
As such a chemically amplified resist, Japanese Patent Application Laid-open No. 45439/1984 discloses a combination of a resin protected with a t-butyl group or a t-butoxycarbonyl group and a photoacid generator. Japanese Patent Application Laid-open No. 52845/1985 discloses a combination of a resin protected by a silyl group and a photoacid generator. In addition to these resist compositions, there are a number of reports dealing with chemically amplified resists, such as a resist which contains a resin protected by an acetal group and a photoacid generator (Japanese Patent Application Laid-open No. 25850/1990).
However, since each of these conventional chemically-amplified resists have peculiar problems, various problems in putting these resists to practical use for microfabrication with a line width of 0.25 &mgr;m or less have been pointed out. A first problem is a tendency of being affected by an optical proximity effect, which induces a dimensional difference according to pattern density, round pattern ends, and recess phenomenon. A dimensional difference according to pattern density makes it impossible to obtain a designed independent line pattern when the resist is exposed to radiation at an optimum dose for the line-and-space pattern. Such a resist cannot satisfy the requirement for one-chip memory cards in recent logic circuits. A second problem is lack of capability of providing a sufficient focusing allowance to isolated patterns, in particular, failing the resist to satisfy the requirement for logic circuits with a high specialty and commercial value.
For these reasons, a resist which not only excels in sensitivity and resolution, but also exhibits only a minimal optical proximity effect and is capable of forming fine patterns at a high precision and in a stable manner even if the patterns are isolated line patterns, thereby providing isolated line patterns with a sufficient focusing allowance is desired.
An object of the present invention is to provide a photo-sensitive resin composition useful as a positive-tone or negative-tone chemically amplified resist which effectively responds to various radiations, excels in sensitivity and resolution, exhibits only a minimal optical proximity effect, is capable of forming fine patterns at a high precision and in a stable manner even if the patterns are isolated line patterns, and can provide isolated line patterns with a sufficient focusing allowance.
SUMMARY OF THE INVENTION
According to the present invention, the above object can be achieved by a positive-tone radiation-sensitive resin composition comprising: (A) a low molecular weight compound having at least one amino group in which the nitrogen atom has at least one hydrogen atom bonded thereto and at least one of the hydrogen atoms is replaced by a t-butoxycarbonyl group, (B) a photoacid generator, and (C-1) a resin insoluble or scarcely soluble in alkali which is protected by an acid-dissociable group and becomes soluble in alkali when the acid-dissociable group dissociates or (C-2) an alkali-soluble resin and an alkali solubility control agent (hereinafter referred to as “first invention”).
In the above positive tone radiation-sensitive resin composition, the low molecular weight compound (A) is preferably at least one compound selected from the group consisting of the compounds shown by the following formula (1),
wherein R
1
and R
2
individually represent a hydrogen atom, a linear, branched, or cyclic alkyl group, aryl group, or aralkyl group which are either substituted or unsubstituted, compounds having two nitrogen atoms in the molecule, compounds having three or more nitrogen atoms in the molecule, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds.
In the above positive tone radiation-sensitive resin composition, the low molecular weight compound (A) is preferably a compound of which the conjugated acid has a pKa determined at 25° C. of 0 or more.
In the above positive tone radiation-sensitive resin composition, the photoacid generator (B) is preferably selected from the group consisting of onium salt compounds, sulfone compounds, sulfonate compounds, sulfonimide compounds, diazomethane compounds, and disulfonylmethane compounds.
The above positive tone radiation-sensitive resin composition preferably further comprises an acid diffusion control agent which is a compound other than the low molecular weight compound (A).
In the above positive tone radiation-sensitive resin composition, the acid diffusion control agent is preferably a nitrogen-containing compound.
In the above positive tone radiation-sensitive resin composition, the resin (C-1) is preferably a resin derived from an alkali-soluble resin having any recurring unit represented by the following formulas (2)-(5), in which the hydrogen atom of an acid functional group is replaced by at least one acid-dissociable group which dissociates in the presence of an acid:
wherein R
3
represents a hydrogen atom or a methyl group, R
4
represents a hydroxyl group, a carboxyl group, —R
5
COOH, —OR
5
COOH, —OCOR
5
COOH, or —COOR
5
COOH (R
5
is a group —(CH
2
)
9
—, wherein g is an integer of 1-4),
wherein R
6
represents a hydrogen atom or a methyl group,
wherein R
7
, R
8
, R
9
, R
10
, and R
11
individually represent a hydrogen atom or an alkyl group having 1-4 carbon atoms.
In the above positive tone radiation-sensitive resin composition, the acid-dissociable group is preferably selected from the group consisting of a substituted methyl group, 1-substituted ethyl group, 1-substituted n-propyl group, 1-branched alkyl group, silyl group, germyl group, alkoxycarbonyl group, acyl group, and cyclic acid-dissociable group.
In the above positive tone radiation-sensitive resin composition, the resin (C-1) is preferably a resin having an alicyclic structure in the main chain and/or side chain and a carboxylic acid anhydride structure in the side chain.
In the above positive tone radiation-sensitive resin composition, the resin (
Hara Hiromichi
Kajita Toru
Murata Kiyoshi
Natsume Norihiro
Numata Jun
Baxter Janet
JSR Corporation
Kelber Steven B.
Piper Rudnick LLP
Thornton Yvette C.
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