Photo-curable resist resin composition for electroless plating, process for preparing a printed circuit board with the said resist resin composition and a printed circuit board having resist prepared from the said resist resin composition

• US 4,820,549 A
• Filed: 05/19/1987
• Issued: 04/11/1989
• Est. Priority Date: 05/20/1986
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ozaki, Kiyoshi, Tsuda, Hideo, Mori, Atsushi, Kawamoto, Mineo, Murakami, Kanji, Wajima, Motoyo
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): DANG, VI
• Application Number:
  US07/051,518
• Time in Patent Office: 693 Days
• Field of Search: 427/98, 427/96, 427/306, 428/901, 361/397
• US Class Current: 427/98.5
• CPC Class Codes: C08G 59/145 Compounds containing one epoxy group
• CPC Class Codes: C08G 59/226 Mixtures of di-epoxy compounds
• CPC Class Codes: C08G 59/38 together with di-epoxy compounds
• CPC Class Codes: C08G 59/68 characterised by the catalysts used
• CPC Class Codes: G03F 7/0385 using epoxidised novolak resin
• CPC Class Codes: H05K 3/0076 characterised by the composition of the mask
• CPC Class Codes: H05K 3/184 using masks

Abstract

A photo-curable resist resin composition for electroless plating comprising an epoxy resin having a viscosity of at least 150 poises at 25° C., and at least two glycidyl ether groups in one molecule, the glycidyl ether groups being directly bonded to the aromatic ring as Component A, an oxirane ring-containing compound having a boiling point of at least 140° C. and a molecular weight of not more than 500 as Component B, and a photo-sensitive aromatic onium salt as Component C, wherein the Component A is in an amount of 90 to 40 parts by weight per total 100 parts by weight of the Components A and B, and the Component C is in an amount of 0.1 to 5 parts by weight per total 100 parts by weight of the Components A and B, and, if any, other resin components, can produce a resist film capable of withstanding highly alkaline electroless copper plating solution at a high temperature for a long time without any decrease in the physical properties of plating films deposited even by repeated use of the electroless copper plating solution. The resist film prepared from the resist resin composition has distinguished soldering heat resistance, solvent resistance and electrical insulation.

Claims

1. A process for preparing a printed circuit board, where a circuit is formed by electroless plating a circuit-forming part having at least a noble metal catalyst reactive to deposition of electroless plating on an adhesive layer surface provided on the insulating substrate, the other parts than the circuit-forming part being coated with a plating resist, which comprises forming the plating resist with a photo-curable resist resin composition for electroless plating, which comprises:

an epoxy resin having a viscosity of at least 150 poises at 25°

C., and at least two glycidyl ether groups in one molecule, the glycidyl ether groups being directly bonded to the aromatic ring, as Component A,

an oxirane ring-containing compound having a boiling point of at least 140°

C. and a molecular weight of not more than 500 as Component B, and

a photo-sensitive aromatic onium salt as Component C, wherein the Component A is in an amount of 90 to 40 parts by weight per total 100 parts by weight of the Components A and B, and the component C is in an amount of 0.1 to 5 parts by weight per total 100 parts by weight of the Components A and B, and, if any, other resin components.

2. A process for preparing a printed circuit board, which comprises chemically roughening a heat-curable adhesive provided on an insulating substrate, depositing a catalyst as an initiator for electroless plating reaction on the entire surface of the chemically roughened adhesive, screen-printing a photo-curable resist ink composition for electroless plating comprising:

(1) 40 to 90 parts by weight of at least one of bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolak type epoxy resin and hydrogenated bisphenol A glycidyl ether resin, the epoxy resins having a viscosity of at least 150 poises at 25°

C. and at least two glycidyl ether groups in one molecule, the glycidyl ether groups being directly bonded to the aromatic ring, as Component A;

(2) 60 to 10 parts by weight of at least one oxirane ring-containing compound having a boiling point of 140°

C. or more and a molecular weight of not more than 500 selected from epoxy monomers, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin and hydrogenated bisphenol A type epoxy resin as Component B serving as a reactive diluent for Component A, total amount of said Components A and B being 100 parts by weight;

(3) 0.1 to 5 parts by weight per total weight of said Components A and B of a photosensitive aromatic onium salt selected from triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate and diphenyliodonium tetrafluoroborate as Component C serving as a curing agent for said Components A and B;

(4) 1 to 25 parts by weight per 100 parts by total weight of said Components A, B an C of at least one inorganic filler selected from zirconium silicate, talc and quartz as Component D;

(5) 0.5 to 4 parts by weight per total 100 parts by weight of said Component A, B an C of silicone oil as Component E serving as a defoaming agent;

(6) 0.5 to 5 parts by weight per total 100 parts by weight of said Components A, B and C of at least one leveling agent selected from fluorine-based surfactants, silicone-based surfactants, silicone-modified epoxy resin and non-aqueous acrylic copolymers as Component F serving as a levelling agent; and

(7) 0.5 to 5 parts by weight per total 100 parts by weight of said Components A, B and C of a coloring agent selected from clay and barium sulfate as extender pigments, titanium oxide and carbon black as inorganic pigments, titanium oxide and carbon black as inorganic pigments and phthalocyanine blue and phthalocyanine green as organic pigments as Component G after drying the catalyst, curing the resist resin composition with infrared rays, a nd dipping the resulting substrate into an electroless plating solution, thereby depositing a plating film on circuit-destined parts on the substrate and forming a circuit.

3. A process for preparing a printed circuit board, which comprises screen printing a photo-curable resist ink composition for electroless plating comprising:

(1) 40 to 90 parts by weight of at least one of bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolak type epoxy resin and hydrogenated bisphenol A glycidyl ether resin, the epoxy resins having a viscosity of at least 150 poises at 25°

C. and at least two glycidyl ether groups in one molecule, the glycidyl ether groups being directly bonded to the aromatic ring, as Component A;

(2) 60 to 10 parts by weight of at least one oxirane ring-containing compound having a boiling point of 140°

C. or more and a molecular weight of not more than 500 selected from epoxy monomers, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin and hydrogenated bisphenol A type epoxy resin as Component B serving as a reactive diluent for Component A, total amount of said Components A and B being 100 parts by weight;

(3) 0.1 to 5 parts by weight per total weight of said Components A and B of a photosensitive aromatic onium salt selected from triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate and diphenyliodonium tetrafluoroborate as Component C serving as a curing agent for said Components A and B;

(4) 1 to 25 parts by weight per 100 parts by total weight of said Components A, B an C of at least one inorganic filler selected from zirconium silicate, talc and quarts as Component D;

(5) 0.5 to 4 parts by weight per total 100 parts by weight of said Component A, B an C of silicone oil as Component E serving as a defoaming agent;

(6) 0.5 to 5 parts by weight per total 100 parts by weight of said Components A, B and C of at least one leveling agent selected from fluorine-based surfactants, silicone-based surfactants, silicone-modified epoxy resin and non-aqueous acrylic copolymers as Component F serving as a levelling agent; and

(7) 0.5 to 5 parts by weight per total 100 parts by weight of said Components A, B and C of a coloring agent selected from clay and barium sulfate as extender pigments, titanium oxide and carbon black as inorganic pigments, titanium oxide and carbon black as inorganic pigments and phthalocyanine blue and phthalocyanine green as organic pigments as Component G onto other parts than circuit-destined parts on the surface of a heat-curable adhesive provided on an insulating substrate, curing the resist resin composition with ultraviolet rays, then chemically roughening the surface of the adhesive on exposed circuit-destined parts, depositing a catalyst as an initiator for electroless plating reaction on the entire surface, then removing the catalyst deposited on the surface of the resist resin composition with a catalyst-removing solution through dissolution and dipping the resulting substrate into an electroless plating solution, thereby depositing a plating film onto the circuit-destined part and forming a circuit.