Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2001-03-16
2002-05-21
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S192000, C430S193000
Reexamination Certificate
active
06391513
ABSTRACT:
TECHNICAL FIELD
This invention relates to a novel positive-working radiation sensitive resin composition and, more particularly, to a positive-working radiation sensitive resin composition containing a radiation sensitive novolak resin, suited for manufacture of a semiconductor integrated circuit, production of a display surface of a liquid crystal display device in a LCD panel, manufacture of a circuit substrate for a thermal head etc., and like use.
BACKGROUND ART
In the wide field of manufacturing a semiconductor integrated circuit such as a LSI, preparing a display surface of a liquid crystal display device in a LCD panel, manufacturing a circuit substrate for a thermal head etc., and like use, photolithography has so far been employed for forming microelements or conducting fine processing. In the photolithography, a positive- or negative-working radiation sensitive resin composition is used for forming a resist pattern. Of these radiation sensitive resin compositions, those compositions containing an alkali-soluble resin and a photosensitizer of quinonediazide compound are most popularly used as the positive-working radiation sensitive resin compositions. As such compositions, there are described compositions having different formulations as, for example, ‘novolak resin/quinonediazide compound’ in many documents such as Japanese Examined Patent Publication Nos. S54-23570 (U.S. Pat. No. 3,666,473) and S56-30850 (U.S. Pat. No. 4,115,128), Japanese Unexamined Patent Publication Nos. S55-73045, S61-205933 and S62-51459, etc.
These compositions containing a novolak resin and a quinonediazide compound have so far been studied from the viewpoint of both novolak resins and photosensitizers. From the viewpoint of a novolak resin, there have been developed novel resins. In addition, radiation sensitive resin compositions having excellent properties have also been obtained by improving properties of conventionally known resins. For example, there are disclosed techniques providing a radiation sensitive resin composition having excellent properties by using a novolak resin with a particular molecular weight distribution in Japanese Unexamined Patent Publication Nos. S60-140235 and H1-105243 and by using a novolak resin from which low-molecular-weight components of the resin has been removed by fractionation in Japanese Unexamined Patent Publication Nos. S60-97347 and S60-189739 and Japanese Patent Publication No.2590342. From the viewpoint of a photosensitizer, various attempts have been made to develop novel quinonediazide compounds and novel quinonediazide sulfonates. Further, there have been proposed the improvement of the characteristics by a combination of a specific novolak resin and a quinone diazide sulfonate (e.g. Japanese Unexamined Patent Publication H9-90622) or a combination of a specific dissolution promoter and a quinonediazide sulfonate of an alkali- soluble resin such as novolak resin (e.g. Japanese Unexamined Patent Publication No.H10-69077). Above-mentioned Japanese Unexamined Patent Publication Nos. H9-90622 and H10-69077 describe generally that quinonediazide sulfonates are formed by use of quinonediazide compounds having a sulfonic acid group at the 4- or 5-position, and further that such sulfonates of quinonediazide compounds having a sulfonic acid group at the 4- or 5-position are used in combination, but there is no specific disclosure therein on the combined use thereof such as an effect when used in combination thereof, a mixing ratio thereof, and Examples.
A number of positive-working radiation sensitive resin compositions containing quinonediazide compounds have been put into practice as a result of various technical developments having so far been made, and the aspect ratio of thickness of radiation sensitive resin coating to line width resolved has been improved to about 5:1 .
On the other hand, degree of integration of semiconductor integrated circuits have been increased year by year and, in the manufacture thereof, processing of patterns with a line width of less than sub-micron order has become required. In the uses requiring such super-fine processing, good pattern reproducibility is required as well as high resolution and, from the standpoint of production cost, it is also required to improve throughput (yield per unit time) upon production by meeting the high sensitization. However, conventionally known radiation sensitive resin compositions can not satisfy these requirements at the same time, thus being a problem.
Under the circumstances with problems described above, an object of the present invention is to provide a positive-working radiation sensitive resin composition which has high sensitivity and high resolution and can form a good pattern.
DISCLOSURE OF THE INVENTION
As a result of intensive investigation, the inventors have found that in a positive-working radiation sensitive resin composition comprising a radiation sensitive novolak resin consisting of esterified products between an alkali-soluble novolak resin and naphthoquinonediazide compounds, if said radiation sensitive novolak resin consists of two kinds of esterified products between an alkali-soluble novolak resin and naphthoquinonediazide compounds different in the substitution position of the sulfonic acid group and the mixing ratio of the substituent group is in a specific range, the resulting positive-working radiation sensitive resin composition has high sensitivity, high resolution and ability to form excellent patterns, which cannot be predicted from the prior art, thus having completed the present invention based on the finding.
That is, the present invention relates to a positive-working radiation sensitive resin composition comprising partially esterified products (radiation sensitive novolak resin) between an alkali-soluble novolak resin and o-naphthoquinonediazide compounds, wherein said partially esterified products comprise 1,2-naphthoquinonediazide-4-sulfonic acid ester and 1,2-naphthoquinonediazide-5-sulfonic acid ester, and the ratio by weight of 4-sulfonyl group and 5-sulfonyl group bound to said partially esterified products ranges from 5:95 to 20:80.
The present invention will now be described more specifically below.
An alkali-soluble novolak resin used as a starting material for preparing the radiation sensitive novolak resin of the present invention is a novolak-type phenol resin, and is manufactured by polycondensation between one of phenols or a mixture thereof and an aldehyde such as formalin. The polycondensation between a phenol and an aldehyde may be conducted by any conventionally known processes such as using oxalic acid as a catalyst.
The alkali-soluble novolak resin may be the one from which low-molecular components were removed by suitable fractionation treatment such as re-precipitation. The removal of low-molecular components is conducted usually before the reaction between the alkali-soluble novolak resin and the naphthoquinonediazide compounds. Alternatively, after the reaction of the alkali-soluble novolak resin and the naphthoquinonediazide compounds, the reaction products may be treated in the same manner as in the above-mentioned fractionation treatment of the novolak resin, so that low-molecular components are removed from the reaction products, and the radiation sensitive novolak resin thus obtained is similar to the one obtained from the novolak resin from which low-molecular components were previously removed. However, from the viewpoint of safety and because of the possible inactivation of the radiation sensitive functional groups by heating at the time of fractionation treatment, the fractionation treatment is conducted preferably before the reaction. If the novolak resin from which low-molecular components were removed by fractionation treatment is used, desired resolution may not be achieved, so a predetermined dissolution inhibitor is preferably blended with it.
In the present invention, there are preferably used an alkali-soluble novolak resin having a dissolution rate of 10 to 300 Å/sec, for a 2.38 wt% aqueous solution
Arano Akio
Nishikawa Masato
Susukida Kenji
Chu John S.
Clariant Finance (BVI) Limited
Jain Sangya
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