To suppress occurrence of short circuit between wiring patterns by eliminating overhand of a protective plated coating, and to enhance reliability by fully ensuring adhesion of solder resist.
In a copper layer 21 at a part which is to become a wiring pattern, a first resist pattern 41 exposing a required part to be plated is formed on the opposite sides of a copper clad substrate 20. Plating is then performed using the first resist pattern 41 as a mask to form a plated coating 42 at the required part of the copper layer 21. After removing the first resist pattern 41, a second resist pattern 43 is formed on the opposite sides of the copper clad substrate 20 to cover the plated coating 42 and the copper layer 21 at a part which is to become a wiring pattern 14. Thereafter, the copper layer 21 is etched, using the second resist pattern 43 as a mask to form a required wiring pattern 14. Finally, the second resist pattern 43 is removed, and a solder resist layer 32 exposing the plated coating 42 is formed on the opposite sides of the copper clad substrate 20.
UCHIKAWA MASAKI
MATSUOKA MASAAKI
YODA EIJI
