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
1999-11-24
2002-04-09
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
C430S270100, C430S325000
Reexamination Certificate
active
06368773
ABSTRACT:
FIELD OF INVENTION
The present invention relates to cross-linking agents (“cross-linkers”) usable for photoresist compositions, the polymers thereof, and photoresist compositions comprising the same. More specifically, it relates to cross-linking agents used in photoresists suitable for photolithography processes using a KrF (248 nm), ArF (193 nm), E-beam, ion beam or EUV light source when preparing a microcircuit of a highly integrated semiconductor element, and photoresist compositions employing the same.
BACKGROUND OF THE INVENTION
Recently, chemical amplification type DUV (deep ultra violet) photoresists have proven to be useful to achieve high sensitivity in processes for preparing micro-circuits in the manufacture of semiconductors. These photoresists are prepared by blending a photoacid generator with polymer matrix macromolecules having acid labile structures.
According to the reaction mechanism of such a photoresist, the photoacid generator generates acid when it is irradiated by the light source, and the main chain or branched chain of the polymer matrix macromolecule is cross-linked with the generated acid to form a cross-linked structure. Thus, the portion exposed to light cannot be dissolved by developing solution and remains unchanged, thereby producing a negative image of a mask on the substrate. In the lithography process, resolution depends upon the wavelength of the light source—the shorter the wavelength, the smaller the pattern that can be formed. However, when the wavelength of the light source is decreased in order to form a micro pattern [for example, in the case of using 193 nm wavelength or EUV (extremely ultraviolet) light], it is disadvantageous in that the lens of the exposing device is deformed by the light source, thereby shortening its life.
Melamine, a conventional cross-linker, has a limited number (three) of functional groups which can form a cross-linkage with acid. Further, a large amount of acid must be generated when melamine is used as a cross-linker, because acid is consumed by the cross-linking reaction. As a result, high energy light exposure is required for such cross-linking agents.
In order to overcome the disadvantages described above, chemical amplification type compounds that cross-link with a photoresist resin and use less amounts of energy are desirable. However, such chemical amplification type cross-linkers have not yet been developed.
Furthermore, in a pattern of high integrity, developing solution may be soaked into the cross-linked site, to swell up the cross-linked site. Thus, in order to form a pattern of higher integrity, the incorporation of a novel cross-linker, which performs cross-linking more elaborately, is required.
FIG. 1
shows a photoresist pattern that was formed by using a photoresist composition comprising a conventional cross-linker (
J. Photopolymer Science and Technology
, Vol.11, No.3, 1998, 507-512). The pattern is a 0.225 &mgr;m L/S pattern obtained by a photolithography process employing an ArF light source and a monomeric cross-linker.
As can be shown from
FIG. 1
, swelling occurs in a conventional photoresist pattern, so that a pattern of less than 0.225 &mgr;m L/S is difficult to obtain.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a photoresist cross-linker, and a process for preparing the same.
Another object of the present invention is to provide a photoresist composition comprising a cross-linker, and a process for preparing the composition.
Still another object of the invention is to provide a semiconductor element manufactured by using the photoresist composition.
In order to achieve these objects, the present invention provides a cross-linker monomer that comprises a compound represented by following Chemical Formula 1:
<Chemical Formula 1>
wherein, R
1
and R
2
individually represent straight or branched C
1-10
alkyl, straight or branched C
1-10
ester, straight or branched C
1-10
ketone, straight or branched C
1-10
carboxylic acid, straight or branched C
1-10
acetal, straight or branched C
1-10
alkyl including at least one hydroxyl group, straight or branched C
1-10
ester including at least one hydroxyl group, straight or branched C
1-10
ketone including at least one hydroxyl group, straight or branched C
1-10
carboxylic acid including at least one hydroxyl group, and straight or branched C
1-10
acetal including at least one hydroxyl group; and R
3
represents hydrogen or methyl.
In order to achieve another object of the present invention, a photoresist composition is provided which comprises (i) a photoresist polymer, (ii) a photoresist cross-linker as described above, (iii) a photoacid generator and (iv) an organic solvent.
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patent: 4562009 (1985-12-01), Lysenko et al.
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patent: 6121399 (2000-09-01), Webster et al.
patent: 6184263 (2001-02-01), Narang et al.
patent: 3714276 (1988-11-01), None
patent: 0 100 071 (1984-02-01), None
patent: 695789 (1953-08-01), None
Academic Press Dictionary of Science and Technology definitions of acetal, alkyl, carboxylic acid, ester and ketone.*
CA90:138248, Sastre et al, Angew. Makromol. Chem. 1978, 73, 25-33.*
U.S. application No. 09/448,964, Jung et al., filed Nov. 24, 1999.
Chemical Abstract No. 110:96578.
Baik Ki Ho
Jung Jae Chang
Kim Hyeong Soo
Kim Hyoung Gi
Kim Jin Soo
Ashton Rosemary
Hyundai Electronics Industries Co,. Ltd.
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