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
1999-12-03
2002-07-16
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
C430S283100, C430S287100, C430S325000, C522S066000
Reexamination Certificate
active
06420090
ABSTRACT:
BACKGROUND ART
(1) Field of the Invention
The present invention relates to a liquid photocurable composition and a water-based photocurable composition, and particularly to a photocurable composition for use in a printed circuit board. The liquid photocurable composition and water-based photocurable composition of the present invention is applicable to a solder resist, etching resist, anti-plating resist, UV ink and the like.
(2) Description of Background Art
A method of forming a conductor circuit such as a printed circuit board is known in the art, which comprises coating a photocurable resist composition onto a board, followed by exposing to light, developing to form a resist pattern, and by etching to remove unnecessary portion.
For example, a photocurable resist composition capable of developing with a weak alkali by use of an unsaturated resin having carboxyl group is known as the above photocurable resist composition (see Japanese Patent Application Laid-Open No. 223759/91).
The above carboxyl group-containing unsaturated resin is usually prepared as described in the above prior art by a process which comprises subjecting an acid unsaturated monomer such as acrylic acid with alkyl (meth)acrylate monomer to a radical copolymerization reaction to obtain a polycaroxylic acid resin, followed by subjecting the resin and an epoxy group-containing unsaturated monomer such as glycidyl (meth)acrylate to an addition reaction of a part of the carboxyl group-containing alkyl (meth)acrylate monomer with glycidyl group.
The use of the above acid resin as an alkali development type resist composition had such problems (1) that a broad molecular weight distribution of the acid resin prepared by the radical polymerization reaction causes a reduction of solubility due to an alkali developing solution or etching solution in a high molecular weight region and an increase of solubility due to the alkali developing solution or etching solution in a low molecular weight region, resulting in making it impossible to carry out a uniform developing treatment or etching treatment, (2) that difference of a radical copolymerization reaction speed between a (meth)acrylic acid monomer component and alkyl (meth)acrylate monomer may produce a homopolymer of the acrylic acid monomer or an acrylic resin containing the acrylic acid component in a small amount, resulting in that formation of a fine resist pattern is made impossible due to non-uniform speed of removing the resist film by the alkali developing treatment, remaining of the resist film in a short period of treating time, and to erosion and washing out of a photocured film, (3) that heating on the addition reaction between the polycarboxylic acid resin and the epoxy group-containing unsaturated monomer further increases molecular weight of the polycarboxylic acid resin, (4) that unnecessary presence with the resin of a radical polymerization inhibitor usually added for the purpose of inhibiting the radical polymerization reaction unsaturated groups on the addition reaction reduces reactivity of the photopolymerization reaction, and (5) that erosion and washing out of the photocured film by the etching solution due to unsatisfactory properties of the photocured film makes it impossible to form a fine resist pattern.
As a method of introducing an unsaturated group into the resin, in addition to the above method, for example, Japanese Patent Appliction Laid-Open No. 102037/95 discloses a process for preparing a water-soluble actinic radiation-curable resin which comprises reacting a polyhydroxy compound, radically polymerizable unsaturated group-containing polyhydroxy compound, anionic hydrophilic group-containing polyhydroxy compound, polyisocyanate compound and radically polymerizable unsaturated group-containing monohydroxy compound to obtain a polyurethane resin, followed by neutralizing with an amine. However, use of the above water-soluble polyurethane resin as a resist composition produced such problems that poor alkali developing properties and anti-etching properties make it impossible to form a fine resist pattern.
As another method of introducing an unsaturated group into the resin, Japanese Patent Application Laid-Open No. 136077/94 discloses a radiation-curable resin composition prepared by reacting a reaction product of dimethylol propionic acid with &egr;-caprolactone, organic polyisocyanate compound and hydroxyl group-containing (meth)acrylate. However, use of the above resin composition as the resist composition had problems of poor properties in alkali developing properties, anti-etching properties and the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a liquid or water-based photocurable composition showing good properties in alkali developing properties, anti-etching resist properties and capable of forming a fine pattern.
It is another object of the present invention to provide a method of forming a fine pattern by use of the liquid or water-based photo curable composition.
That is, the present invention provides, in a first embodiment, a liquid photocurable composition containing a photopolymerizable polyurethane compound having a repeating unit represented by the following formula: B—[X]
n
[Y]
m
—B, where X is represented by the formula:
and Y is represented by the formula: —OOCHN—A—NHCOO(R
2
)—, A is a structural unit derived from a polyisocyanate compound, B is same or different and a structural unit derived from a hydroxy compound having at least one photopolymerizable unsaturated group at molecular terminals respectively and optionally containing an ether linkage, R
1
is a structural unit derived from a carboxyl group-containing polyol compound, R
2
is a structural unit derived from a polyol compound, n is an integer of 1 to 10, m is an integer of 1 to 10, provided that one X and one Y are bonded to each other, or three or more of X and/or Y are bonded to each other, and optionally containing a photopolymerizable compound other than the photopolymerizable polyurethane compound.
The present invention provides, in a second embodiment, a water-based photocurable composition prepared by dispersing the liquid photocurable composition in the first embodiment of the present invention.
The present invention provides, in a third embodiment, a method of forming a resist pattern comprising the following steps: (1) coating the liquid photocurable composition or the water-based photocurable composition onto a substrate to form a photocurable resist film, (2) exposing the photocurable resist film directly to a laser beam or through a negative mask to light for curing so that a resist film having a predetermined printed image can be formed; and (3) carrying out an alkali developing treatment to form a resist pattern on the substrate.
DETAILED DESCRIPTION OF THE INVENTION
The photopolymerizable polyurethane compound used in the present invention is a compound represented by the above formulas. Respective compounds, from which respective structural units in the above formulas are formed, are a polyisocyanate compound, hydroxy compound having at least one photocurable unsaturated group at molecular terminals, carboxyl group-containing polyol compound and polyol compound respectively these compounds are explained hereinafter.
The polyisocyanate compound is used for bonding a compound introducing carboxyl group into the molecule to a compound introducing photopolymerizable unsaturated group at molecular terminals.
The polyisocyanate compound may include aliphatic diisocyanate compound such as hexamethylene diisocyanate, trimethylenediisocyanate, 1,4-tetramethylene-diisocyanate, pentamethylenediisocyanate, 1,2-propylenediisocyanate, 1,2-butylene-diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, lysinediisocyanate, 2,3-butylenediisocyanate, 1,3-butylene-diisocyanate and the like; alicyclic diisocyanate compound such as isophoronediisocyanate, 4,4′-methylene bis(cyclohexylisocyanate), methylcyclohexane-2,4-(or -2,6-) diisocyanate, 1,3-(or 1,4-)-di(isocyan
Akui Jun
Imai Genji
Isozaki Osamu
Kogure Hideo
Kojima Daisuke
Ashton Rosemary
Fisher Christen & Sabol
Kansai Paint Co. Ltd.
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