Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Forming nonplanar surface
Patent
1992-08-27
1994-08-23
McCamish, Marion E.
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Forming nonplanar surface
430324, 430325, G03C 500
Patent
active
053407024
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present Invention relates to a method of forming a thick, fine resist pattern.
TECHNICAL BACKGROUND
Most of electronic machines produced in recent years have many semiconductor devices and many circuit substrates. Patterns for wiring and connection terminals in these semiconductor devices and circuit substrates are generally produced by a processing technique in which a thin, fine resist pattern of a photosensitive resin (to be referred to as "photoresist" hereinafter) is formed on a substrate and then, the substrate is etched.
The formation of a thin, fine resist pattern of a photoresist is generally carried out by a method In which the film surface of the photoresist formed on a substrate is exposed to light through a photomask having a light-shielding pattern.
In the above method, generally, the film thickness of a photoresist formed on a substrate is 0.5 to 3 .mu.m when the photoresist is formed by coating a solution of the photoresist, and the film thickness is less than 50 .mu.m even when a film-like photoresist called a dry film is stacked. Therefore, the film thickness of a fine resist pattern formed by the above method is inevitably less than 50 .mu.m.
Meanwhile, for example, in the production of a printed circuit substrate on which a semiconductor device is to be mounted directly and a mounting wiring substrate typified by TAB (tape automated bonding) for connecting lead frames or a semiconductor device to a printed circuit substrate, it is being desired to establish a technique for forming a highly accurate resist pattern having, for example, a thickness of 50 to 500 .mu.m.
In the above method, however, when a photoresist formed on a substrate has a film thickness of 50 .mu.m or more, it is required to increase exposure energy so that the photoresist is exposed up to its bottom in exposing the photoresist to light through a photomask. However, when the exposure energy is increased, ultraviolet light reaches even a place below a pattern of a light-shielding film, and no proper pattern can be obtained.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a novel method of forming a thick, fine resist pattern.
It is another object of the present invention to provide a method of forming a thick, fine resist pattern, in which a light-shielding film is formed directly on a photoresist, and the photoresist is exposed to light and is developed to form a fine resist pattern.
Other objects and advantages of the present invention will be apparent from the following description.
According to the present invention, the above objects and advantages of the present invention are achieved by a method of forming a fine resist pattern, which comprises: of the positive photoresist,
The present invention will be detailed hereinafter.
As described above, in the step (a) of the method of the present invention, a thick film of a positive photoresist is formed on a substrate.
The positive photoresist used in this (a) step is preferably selected from those which are developed with a developer of an alkaline aqueous solution. Examples of this positive photoresist include a positive photoresist obtained by mixing a resin which is soluble in an alkaline aqueous solution (to be referred to as "alkali-soluble resin" hereinafter) with 1,2-quinonediazidesulfonic acid ester and a positive photoresist consisting of a compound obtained by condensing an alkali-soluble resin and 1,2-quinonediazidesulfonic acid halide.
Examples of the alkali-soluble resin include a novolak resin, polyhydroxystyrene or its derivative, a styrene-maleic anhydride copolymer, cellulose acetate hydrodiene phthalate, polyvinyl hydroxybenzoate, polyhydroxybenzal, and a carboxyl group-containing acrylic resin.
Of the above alkali-soluble resins, preferred are a novolak resin and polyhydroxystyrene or its derivative.
The above novolak resin is obtained by addition-condensing an aromatic compound having a phenolic hydroxyl group (to be simply referred to as "phenol" hereinafter) and an aldehyde in the presen
REFERENCES:
patent: 3873361 (1975-03-01), Franco et al.
patent: 5169494 (1992-12-01), Hashimoto et al.
Technical Digest, Dec. 1982, pp. 391-394, "International Electron Devices Meeting".
Solid State Technology, vol. 29, No. 6, Jun. 1986, pp. 143-148, "Multilayer Resist Processing: Economic Considerations".
Patent Abstracts of Japan, vol. 14, No. 264 (P-1057)7, Jun. 1990, JP-A-20 72 364.
Hirasawa Hiroyuki
Kobayashi Minako
Matsuki Yasuo
Chapman Mark A.
Japan Synthetic Rubber Co. Ltd.
McCamish Marion E.
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