Formation method of metal layer on resin layer, printed wiring board, and production method thereof

Abstract

A printed wiring board having a conductor circuit comprising a copper layer adjacent to an insulating layer and an electroless gold plating, wherein the insulating layer has ten-point mean surface roughness (Rz) of 2.0 μm or less is provided. According to the present invention, there is no such a defect that gold plating is deposited on a resin, and fine wiring formation with accuracy is realized.

1 . A production method of a printed wiring board involving forming a circuit on a substrate which has a copper foil on an insulating layer and carrying out electroless gold plating on the circuit, wherein the face of the copper foil contacting the insulating layer has ten-point mean surface roughness (Rz) of 2.0 μm or less. 
     
     
         2 . A production method of a printed wiring board involving forming a circuit on a substrate which has a copper foil on an insulating layer and carrying out electroless gold plating on the circuit, wherein the face of the copper foil contacting the insulating layer is not practically surface-roughened. 
     
     
         3 . The production method of a printed wiring board according to  claim 1 , including steps of forming holes penetrating the insulating layer and the copper foil for interlayer connection, carrying out electroless copper plating in the holes and on the copper foil, forming a resist layer on the portion where no conductor circuit is to be formed, carrying out patterned electrolytic copper plating in the holes and on the copper foil, removing the resist layer, and removing the copper foil and the electroless copper plating in the portions other than the portion to be the conductor circuit by etching. 
     
     
         4 . The production method of a printed wiring board according to  claim 3 , wherein the step of removing the portions other than the portion to be the conductor circuit by etching is carried out by etching with a chemical solution containing sulfuric acid and hydrogen peroxide as main components. 
     
     
         5 . The production method of a printed wiring board according to  claim 4 , wherein the concentration of sulfuric acid is 5 to 300 g/L and the concentration of hydrogen peroxide is 5 to 200 g/L. 
     
     
         6 . The production method of a printed wiring board according to  claim 1 , involving electroless nickel plating before electroless gold plating. 
     
     
         7 . The production method of a printed wiring board according to  claim 1 , involving electroless palladium plating before electroless gold plating. 
     
     
         8 . The production method of a printed wiring board according to  claim 1 , wherein the minimum pitch of the conductor circuit is 80 μm or narrower. 
     
     
         9 . A production method of a printed wiring board involving forming a conductor circuit by patterned electroplating using a metal foil firmly fixed on an insulating layer as an electric power supply layer, wherein the metal foil is not surface-roughened in both faces and an adhesive layer is inserted between the insulating resin and the metal foil. 
     
     
         10 . The production method of a printed wiring board according to  claim 9 , wherein the metal foil has ten-point mean surface roughness (Rz) of 2.0 μm or less in both faces. 
     
     
         11 . (The production method of a printed wiring board according to  claim 9 , wherein the metal foil has a thickness of 3 μm or thinner. 
     
     
         12 . The production method of a printed wiring board according to  claim 9 , wherein an electroless plating layer is formed on the metal foil. 
     
     
         13 . The production method of a printed wiring board according to  claim 2 , including steps of forming holes penetrating the insulating layer and the copper foil for interlayer connection, carrying out electroless copper plating in the holes and on the copper foil, forming a resist layer on the portion where no conductor circuit is to be formed, carrying out patterned electrolytic copper plating in the holes and on the copper foil, removing the resist layer, and removing the copper foil and the electroless copper plating in the portions other than the portion to be the conductor circuit by etching. 
     
     
         14 . The production method of a printed wiring board according to  claim 13 , wherein the step of removing the portions other than the portions to be the conductor circuit by etching is carried out by etching with a chemical solution containing sulfuric acid and hydrogen peroxide as main components. 
     
     
         15 . The production method of a printed wiring board according to  claim 2 , involving electroless nickel plating before electroless gold plating. 
     
     
         16 . The production method of a printed wiring board according to  claim 2 , involving electroless palladium plating before electroless gold plating. 
     
     
         17 . The production method of a printed wiring board according to  claim 2 , wherein the minimum pitch of the conductor circuit is 80 μm or narrower.