Patent ID: 8231766

Claim:
A method for producing a printed wiring board, the method comprising steps of: treating a surface of a board made of at least one resin selected from among the group consisting of polyimide, polyethylene naphthalate, polyamide-imide, polyethylene terephthalate, wholly aromatic polyamide, liquid crystalline polyester, and fluorine resin for forming a conductor wiring thereon by the following surface treatment method: surface roughening treatment for achieving center line average roughness Ra in a range from 40 to 200 nm followed by the step of forming a porous metal layer made of at least one kind of metal selected from among the group consisting of Al, Cr, Co, Ni, Cu and Ag, by sputtering; forming a conductor wiring by printing an electrically conductive paste containing metal particles M used as an electrically conductive filler made of at least one kind of metal selected from among the group consisting of Cu and Ag having an average particle diameter of 4 μm or smaller and maximum particle diameter of 15 μm or smaller and a binder B in volume ratio of M/B=1/1 to 1.9/1 on the surface of the board for the printed wiring; and forming a plating layer by plating on the surface of the conductor wiring where the metal particles have been exposed by etching the surface of the conductor wiring on at least a portion thereof used for connection with an external circuit so as to expose the metal particles on the surface.