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
2000-03-08
2002-09-03
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
C430S170000, C430S155000, C430S271100, C430S905000
Reexamination Certificate
active
06444394
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a positive-working photoresist composition or, more particularly, to a positive-working chemical-amplification photoresist composition capable of being in compliance with various requirements for the performance of the photoresist relative to photosensitivity, pattern resolution, heat resistance, focusing-depth latitude, cross sectional profile of patterned resist layers, holding stability of coating layers of the composition, dependence on the nature of the substrate surface and so on as well as good reproducibility of product quality.
As compared with conventional photoresist compositions containing a naphthoquinone diazide sulfonic acid ester as the photosensitive ingredient and a novolak resin as the film-forming ingredient, photoresist compositions of the chemical-amplification type exhibit excellent photosensitivity and pattern resolution so that they are highlighted in recent years in the photolithographic technology for the manufacture of fine electronic devices. As a result of extensive investigations to accomplish improvements of the photoresist performance, a great variety of chemical-amplification photoresist compositions have been proposed, some of which are already under current use in the electronic industry.
Chemical-amplification photoresist compositions can be classified into positive-working and negative-working photoresist compositions, each of which comprises a radiation-sensitive acid-generating agent capable of releasing an acid by the irradiation with a radiation such as ultraviolet light and a film-forming resinous ingredient which is subject to a change in the solubility behavior in an aqueous alkaline solution by interacting with the acid.
In a positive-working photoresist composition of the chemical-amplification type, a typical film-forming resinous ingredient is a polyhydroxystyrene resin of which a part of the hydroxyl groups are substituted by tertiary alkoxycarbonyl groups such as tert-butoxycarbonyl groups or cyclic ether groups such as tetrahydropyranyl groups. In a negative-working photoresist composition, on the other hand, the film-forming resinous ingredient is a combination of an acid-crosslinkable compound such as a melamine resin and urea resin with a polyhydroxystyrene resin unsubstituted or substituted for a part of the hydroxyl groups as mentioned above or a novolak resin.
Various proposals and attempts have been made relative to each of the ingredients in the chemical-amplification photoresist compositions with an object to improve the performance of the photoresist layer in respect of photosensitivity, pattern resolution, heat resistance, focusing-depth latitude, cross sectional profile of patterned resist layers, holding stability of the resist layer as formed by coating, dependence on the nature of the substrate surface and other properties.
For example, a positive-working photoresist composition, in which the film-forming resinous ingredient is a combination of two resins having different kinds of the acid-dissociable substituent groups, is disclosed in Japanese Patent Kokai 8-15864, 8-262721, 9-160244, 9-179301, 9-222732, 9-222733, 10-31309 and 10-48826 and elsewhere. A proposal is made in Japanese Patent Kokai 9-160246, 9-211868, 9-274320 and 9-311452 for the use of a ternary copolymeric resin consisting of hydroxystyrene units having acid-dissociable groups of a first type, hydroxystyrene units having acid-dissociable groups of a second type and unsubstituted hydroxystyrene units in a positive-working composition. Japanese Patent Kokai 9-236921 proposes a positive-working photosensitive composition containing an alkali-soluble resin having phenolic hydroxyl groups and a weight-average molecular weight of 6000 to 60000 including 10% by weight or less of the fraction of a molecular weight smaller than 4000 and at least 80% by weight of the fraction of a molecular weight of 4000 to 70000. Japanese Patent Kokai 9-90639 proposes a positive-working composition in which the resinous ingredient is a combination of a high molecular weight polymer substituted by acid-dissociable groups having a molecular weight dispersion of 1.5 or smaller and a low molecular weight polymer substituted by acid-dissociable groups having a molecular weight dispersion of 5.0 or smaller with the proviso that the ratio of the high and low weight-average molecular weights of the resins is at least 1.5. Japanese Patent Kokai 7-199468 proposes a photosensitive composition containing a compound of low polarity of the molecules to exhibit a low dissolving velocity in alkali and another compound of high polarity of the molecules to exhibit a high dissolving velocity in alkali.
As these chemical-amplification positive-working photoresist compositions are produced and consumed in large quantities, various problems have to be solved by the producers thereof in connection with the matter of quality control in order to fully comply with the needs of the consumers.
As for the base resin as the film-forming resinous ingredient playing an important role in the photoresist composition, for example, a serious problem is in the low reproducibility in the quality of the resin products among the preparation lots even if the preparation conditions are controlled constant sometimes leading to an unacceptable product quality. Another problem recently under attention is occurrence of surface defects in the patterned resist layer after development along with the introduction of the surface-defect tester called KLA (a trade name) into the production line of the photoresist consumers.
Along with the recent trend in the semiconductor industries toward finer and finer patterning, some of the photoresist consumers request very delicate modification of the photoresist properties to comply with variations in the exposure light system, nature of the substrate surface, condition of pattern isolation and so on so that the resinous ingredients in the compositions also must comply with the respective requests of the consumers.
SUMMARY OF THE INVENTION
Under the above described technological situations, the present invention has an object to provide a chemical-amplification positive-working photoresist composition having good adaptability to the quality variation among the production lots of the base resin for the resinous film-forming ingredient thus to provide various grades of photoresist products to comply with so diversified requirements of the photoresist consumers.
Thus, the chemical-amplification positive-working photoresist composition of the present invention is a uniform solution in an organic solvent, which comprises:
(A) a polyhydroxystyrene-based resinous ingredient of which the hydroxyl groups are partly substituted by acid-dissociable substituent groups capable of being dissociated by interacting with an acid; and
(B) a radiation-sensitive acid-generating compound capable of releasing an acid by irradiation with a radiation, the resinous ingredient (A) being a combination comprising (A
1
) a first substituted polyhydroxystyrene resin and (A
2
) a second substituted polyhydroxystyrene resin, the substituent groups in the first and second resins (A
1
) and (A
2
) being of the same kind, of which the degree of substitution by the substituent groups for a part of the hydroxyl groups in the first resin (A
1
) is larger than that in the second resin (A
2
) with the proviso that the ratio of the maximum weight-average molecular weight Mw
max
to the minimum weight-average molecular weight Mw
min
in each of the first and second resins (A
1
) and (A
2
), i.e. Mw
max
:Mw
min
, does not exceed 1.5.
REFERENCES:
patent: 5736296 (1998-04-01), Sato et al.
patent: 5750309 (1998-05-01), Hatakeyama et al.
patent: 5817444 (1998-10-01), Sato et al.
patent: 5874195 (1999-02-01), Sato et al.
patent: 5876900 (1999-03-01), Watanabe et al.
patent: 5908730 (1999-06-01), Nitta et al.
patent: 5945248 (1999-08-01), Nitta et al.
patent: 5945517 (1999-08-01), Nitta et al.
patent: 5976759 (1999-11-01), Urano et al.
patent: 6284430 (2001-09-01),
Maemori Satoshi
Nakao Taku
Nitta Kazuyuki
Sato Kazufumi
Baxter Janet
Clarke Yvette M.
Tokyo Ohka Kogyo Co. Ltd.
Wenderoth Lind & Ponack LLP
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