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
2000-02-07
2001-06-19
Hamilton, Cynthia (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
C525S132000, C525S152000, C525S151000, C525S153000, C525S328300, C525S328600
Reexamination Certificate
active
06248500
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a composition for anti-reflective coating material effective for the reduction of adverse effects of reflection by the substrate in a lithographic process using various radiations and a resist pattern formation process which comprises the use of the composition for anti-reflective coating material.
BACKGROUND OF THE INVENTION
A photoresist is applied to a substrate such as semiconductor wafer, glass, ceramic and metal to a thickness of from 0.5 to 2 &mgr;m by a spin coating method or roller coating method. Thereafter, the coated material is heated, dried, exposed to radiation such as ultraviolet rays through an exposure mask to print a circuit pattern thereon, optionally followed by baking, and then developed to form an image thereon.
The coated mask is then etched with this image as a mask to effect a patternwise work on the substrate. Typical examples of fields to this technique is applied include process for the production of semiconductors such as IC and circuit boards for liquid crystal, thermal head, etc., and photofabrication process.
In the fine working of semiconductors using a photoresist, the prevention of reflection of light by the substrate has become more important as the dimensional fineness has developed. Heretofore, to this end, photoresists comprising a light absorber incorporated therein have been used. However, this approach is disadvantageous in that the resolving power is impaired. Therefore, the provision of a bottom anti-reflective coating (BARC) between the photoresist and the substrate has been widely studied.
As the anti-reflective coatings there have been known inorganic coatings made of titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, &agr;-silicone, etc. and organic coatings made of light absorber and polymer. The formation of the former coatings requires apparatus such as vacuum metallizer, CVD apparatus and sputtering apparatus while that of the latter coatings advantageously requires no special apparatus. Thus, the latter coatings have been widely studied.
Examples of the organic anti-reflective coatings include those comprising a condensate of diphenylamine derivative and formaldehyde-modified melamine resin, an alkali-soluble resin and a light absorber as described in JP-B-7-69611 (The term “JP-B” as used herein means an “examined Japanese patent publication”), those comprising a reaction product of maleic anhydride copolymer with diamine type light absorber as described in U.S. Pat. No. 5,294,680, those comprising a resin binder and a methylol melamine heat crosslinking agent as described in JP-A-6-118631 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”), acrylic resin type anti-reflective coatings having a carboxylic acid group, an epoxy group and a light-absorbing group in the same molecule as described in JP-A-6-118656, and those comprising methylol melamine and a benzophenone light absorber as described in JP-A-8-87115.
The physical properties required for these organic anti-reflective coating materials are high absorbance with respect to radiation, insolubility in the resist solvent (no intermixing with the resist layer), higher dry etching rate than resist, etc. as described in
Proc. SPIE
, Vol. 2195, 225-229 (1994).
However, the compounds described in the above cited patents don't meet all of these requirements. Thus, improvements have been desired in this respect. For example, the prior art anti-reflective coatings leave something to be desired in the light absorbing capacity of binder and thus have needed a further light absorber to be incorporated therein. Further, the prevention of intermixing with the resist layer requires the introduction of heat crosslinking effect into the anti-reflective coating. Thus, the crosslinking effect has been introduced into the anti-reflective coating independently of the light absorbing group. Thus, this approach is disadvantageous in that if the crosslinkability of the anti-reflective coating is raised, the absorbance of the anti-reflective coating is reduced. Further, the anti-reflective coating comprising a functional group for enhancing alkali permeability such as carboxylic acid group as a crosslinking system are disadvantageous in that when developed with an aqueous solution of alkali, it is liable to swelling, impairing the shape of the resist pattern.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a composition for anti-reflective coating material which exerts a high anti-reflective effect, undergoes no intermixing with the resist layer, provides an excellent resist pattern and shows a higher dry etching rate than resist and a resist pattern formation process.
The present invention concerns the following embodiments (1) to (10):
(1) A composition for anti-reflective coating material, comprising a polymer compound A having repeating units represented by the following general formulae (I) and (II):
wherein R
1
and R
2
may be the same or different and each represent a hydrogen atom, a methyl group, a chlorine atom, a bromine atom or a cyano group; X represents a single bond or a divalent organic connecting group; P represents a C
6-14
aromatic ring having a valence of (n+1); Y represents an electron donative group; Z represents an organic functional group terminated by —CH
2
OR
3
(in which R
3
represents a hydrogen atom or a C
1-20
hydrocarbon group); and n represents an integer of from 0 to 3, with the proviso that when n is 2 or 3, the plurality of Y's may be the same or different;
(2) The composition for anti-reflective coating material as defined in (1) above, wherein in the general formula (I) X represents a single bond or an alkylene group, an arylene group, an aralkylene group, —CO
2
—A—, —CONH—A—, —O—A—, —CO—A— or —SO
2
—A— (in which A represents a C
6-14
aromatic ring which may have a substituent) having at least one connecting group selected from the group consisting of —CO
2
—, —CONH—, —O—, —CO— and —SO
2
— included therein; P represents a phenylene group, a naphthylene group or an anthrylene group; and Y represents a hydrogen atom, —OH, —OR
4
, —N(R
5
)(R
6
) or —SR
4
(in which R
4
represents a C
1-20
hydrocarbon group, and R
5
and R
6
may be the same or different and each represent a hydrogen atom or a C
1-20
hydrocarbon group);
(3) A process for the formation of a resist pattern, which comprises applying a composition for anti-reflective coating material according to (1) or (2) above to a substrate, baking the coated substrate so that the anti-reflective coating is cured, and then patternwise forming a photoresist layer thereon;
(4) A composition for anti-reflective coating material, comprising:
(a) a polymer compound B having repeating units represented by the following general formula (I); and
(b) a melamine, guanamine or urea compound substituted by at least one group selected from the group consisting of a methylol group and an alkoxymethyl group at two or more positions:
wherein R
1
represents a hydrogen atom, a methyl group, a chlorine atom, a bromine atom or a cyano group; X represents a single bond or a divalent organic connecting group; P represents a C
6-14
aromatic ring having a valence of (n+1); Y represents an electron donative group; and n represents an integer of from 0 to 3, with the proviso that when n is 2 or 3, the plurality of Y's may be the same or different;
(5) The composition for anti-reflective coating material according to (4) above, wherein in the general formula (I) X represents a single bond or an alkylene group, an arylene group, an aralkylene group, —CO
2
—A—, —CONH—A—, —O—A—, —CO—A— or —SO
2
—A— (in which A represents a C
6-14
aromatic ring which may have a substituent) having at least one connecting group selected from the group consisting of —CO
2
—, —CONH—, —O—, —CO— and —SO
2
— included therein; P represents a phenylene group, a naphthylene group, or an anthrylene group; and Y represents a hydrogen atom, —OH, —OR
4
, —N(R
5
)(R
6
) or —SR
4
(
Mizutani Kazuyoshi
Yoshimoto Hiroshi
Fuji Photo Film Co. , Ltd.
Hamilton Cynthia
Sughrue Mion Zinn Macpeak & Seas, PLLC
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