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
1998-08-28
2001-06-05
Hamilton, Cynthia (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
C430S917000, C430S922000, C430S277100, C522S026000
Reexamination Certificate
active
06242158
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is related to a photosensitive resin composition and a photosensitive element using the resin composition. In more detail, this invention is related to a photosensitive resin composition and a photosensitive element using the resin composition, which has excellent sensitivity and adhesion as well as high resolution and plating resistance and can be used as the etching resist and plating resist in the manufacturing of printed circuit board and in the processing of fine metal parts.
PRIOR ART
Currently, photoresist formed by a photosensitive resin composition is commonly used in the manufacturing of printed circuit board, etc. In the method using the photoresist, a photosensitive resin composition is first coated on a support, such as transparent film, etc., to form a photosensitive resin layer. The photosensitive resin layer is then laminated on the surface of a base board on which a pattern is to be formed. Next, the photosensitive resin layer is exposed through a pattern mask carrying the original image. After the exposure, the unexposed part is removed by a solvent or by an aqueous base solution in the development treatment to form a resist image. Finally, by using the resist image as a protecting mask, etching treatment or pattern-plating treatment is carried out with common methods, followed by removing the resist image to give the desired product, such as printed circuit board, etc.
When using the tenting method in the manufacturing process of printed circuit board, the etching is conducted by covering the two side of through holes on the base board with hardened resist. Therefore, this method needs a high-strength hardened film as the resist. Moreover, in the pattern-plating treatment, in order to achieve high density and high resolution for the printed circuit board, the plating resist is required to have excellent adhesion on the surface on the base board, since the contact area of the resist on the surface decreases as the circuit board density increases. In the manufacturing process, in order to increase productivity and decrease production period, the photosensitive resin composition used to form the resist must have a high sensitivity. Since the electric and electronic parts become smaller and smaller, the density of the printed circuit board increases, and consequently the photosensitive resin composition is also required to have high resolution.
In order to satisfy these new requirements, Japanese patent Kokai Hei 3-6202 proposed a photopolymerizable resin composition, which contains 2,4,5-triarylimidazolyl dimer and p-aminophenyl ketone and has excellent tenting capability and high adhesion. Moreover, Japanese patent Kokai Hei 9-101619 reported a photo-hardening resin composition, which contains 2,4,5-triarylimidazolyl dimer and p-hydroxybenzoate ester and has excellent tenting capability and high sensitivity.
Furthermore, in order to further improve the sensitivity and adhesion, Japanese patent Kokai Hei 9-176253 proposed a photosensitive resin composition, which contains hexaarylbiimidazole, an aromatic ketone (N,N′-tetraethyl-4,4′-diaminobenzophenone), an arylglycine (N-phenylglycine), and a photopolymerization initiator. Japanese patent Kokai Hei 9-15856 reported a photosensitive resin composition containing a monomer carrying an isocyanuric ring.
Problems to be Solved by the Invention
However, the resin composition reported in Japanese patent Kokai Hei 3-6202 has a low sensitivity and cannot satisfy the requirements for the practical use, although certain improvements have been achieved in the strength and plating resistance of the hardened film. The technologies proposed in Japanese patents Kokai Hei 9-101619 and Kokai Hei 9-176253 improve the sensitivity. However, the results obtained are still not satisfactory in consideration of the requirements from the recent development in high-density and high-resolution printed circuit boards. Moreover, the method proposed in Japanese patent Kokai Hei 9-176253 is effective in improving the adhesion but not the sensitivity.
In consideration of the current situation described above, the purpose of this invention is to provide a photosensitive resin composition, which has excellent sensitivity and tenting capability as well as high adhesion, resolution, and plating resistance.
Techniques used in Solving the Problems
In order to solve the problems present in the current technologies, the inventors carried out a series of studies. As a result, it was found that the above goal can be achieved by using a photosensitive resin composition, which contains (A) a polymer carrying carboxyl groups, (B) a compound carrying at least one ethylene-based unsaturated group in the molecule, and (C) a photopolymerization initiator, characterized by the fact that component (B) contains at least 60 weight % of methacrylate (B1) carrying at least one ethylene-based unsaturated group with respect to the total amount of component (B), that the amount of component (C) is in the range of 0.01-20 weight units with respect to 100 weight units of component (A) and component (B), and that component (C) contains 2-5 weight units of lophine dimer (C1) and 0.1-2.0 weight units of triphenylphosphine (C2) with respect to 100 weight units of component (A) and component (B). This invention has been completed based on the above discovery.
In addition, the effect of this invention becomes more significant by showing a further improvement in the strength of the hardened film, when the photosensitive resin composition of this invention contains a vinyl urethane derivative, represented by following general formula (1) and/or general formula (2), in component (B) carrying at least one ethylene-based unsaturated group in the molecule.
Chemical Item 1
(in the formula, R represents a hydrogen atom or a methyl group and the two R groups can be the same or different; X represents —CH
2
CH
2
O—; Y represents —CH
2
—CH(CH
3
)—O—, —CH(CH
3
)—CH
2
—O—, —CH
2
CH
2
CH
2
O—, or —CH
2
CH
2
CH
2
CH
2
O—; Z represents a divalent hydrocarbon group; m, n, p, and q are independent of each other and represent an integer of 1-12).
Chemical Item 2
(in the formula, R represents a hydrogen atom or a methyl group and the three R groups can be the same or different; X represents —CH
2
CH
2
O—; Y represents —CH
2
CH(CH
3
)—O—, —CH(CH
3
)—CH
2
O—, —CH
2
CH
2
CH
2
O—, or —CH
2
CH
2
CH
2
CH
2
O—; Z represents a divalent hydrocarbon group; m and p are independent of each other and represent an integer of 1-12)
EMBODIMENT OF THE INVENTION
In the following, this invention is explained in detail.
In this invention, polymer (A) carrying carboxyl groups should mainly consist of (meth)acrylate esters. A (meth)acrylate copolymer with an ethylene-based unsaturated carboxylic acid is very suitable for this purpose. If necessary, other copolymerizable monomers may also be used together. In the copolymer, the content of (meth)acrylate ester should be in the range of 70-85 weight %, preferably 75-82 weight %, the content of the ethylene-based unsaturated carboxylic acid should be in the range of 15-30 weight %, preferably 18-25 weight %, and the content of the other copolymerizable monomers should be in the range of 0-15 weight %.
The (meth)acrylate ester can be, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, etc.
The ethylene-based unsaturated carboxylic acid can be, for example, a monocarboxylic acid, such as acrylic acid, methacrylic acid, crotonic acid, etc., a dicarboxylic acid, such as maleic acid, fumaric acid, itaconic acid, etc., as well as acid anhydrides or half esters of these acids. Among these acids, acrylic acid and methacrylic acid are particularly preferable.
The other copolymerizable monomers can be, for example, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate,
Kosaka Eiji
Murakami Shigeru
Edwards & Angell LLP
Hamilton Cynthia
Nichigo-Morton Co. Ltd.
O'Day Christine C.
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