PRINTED WIRING BOARD, ITS MANUFACTURING METHOD AND CIRCUIT DEVICE

[MEANS FOR SOLVING PROBLEMS] A method of manufacturing a printed wiring board is characterized in that a base metal layer is formed by depositing a base metal on at least one surface of an insulating film, a conductive metal layer is formed by depositing copper or a copper alloy, a surface metal layer formed through the above step is removed selectively by etching so as to form a wiring pattern, and the metal forming the base metal layer is treated with a treating liquid capable of dissolving/immobilizing the metal forming the base metal layer. A printed wiring board is characterized in that it comprises an insulating film and a wiring pattern formed on at least one surface of the insulating film, the wiring pattern comprises a base metal layer deposited on a surface of the insulating film and a conductive metal layer, the base metal layer constituting the wiring pattern is protruded widthwise more than the conductive metal layer constituting the wiring pattern. [EFFECT] Most of the metal forming the base metal layer is removed while the slight remaining metal is immobilized. Thus migration significantly hardly occurs and a highly reliable printed wiring board can be obtained.