Plating method and method for producing a multi-layered printed wiring board using the same

A method for producing a multi-layered printed wiring board, comprising the steps of:

• forming a multi-layered board by forming at least one inner circuit conductor layer on each top and bottom surface of a substrate;
• forming an insulating resin layer to cover the top and bottom surfaces of the multi-layered board;
• forming via holes in the insulating resin layer at desired positions on the multi-layered board, and forming through holes penetrating the multi-layered board at desired positions on the multilayered board;
• dry sandblasting abrasives at least onto a surface of the insulating resin layer and inner faces of the through holes;
• chemically etching the surface of the insulating resin layer;
• plating a conductive layer on the surface of the insulating resin layer subjected to the chemical etching and on the inner face of the through hole;
• and
• patterning the conductive layer into a desired pattern, thereby forming the multi-layered printed wiring board.

A method for producing a multi-layered printed wiring board, comprising the steps of:

• forming an inner circuit conductor layer on each top and bottom surface of a substrate;
• forming through-holes penetrating the inner conductor layer and the substrate;
• electrically connecting the inner circuit conductor layer formed on the top surface of the substrate to the inner circuit conductor layer formed on the bottom surface of the substrate through the through-holes;
• filling the through-holes with a resin;
• forming an insulating resin layer to cover the inner circuit conductor layer;
• forming via holes in the insulating resin layer at desired positions on the multi-layered board;
• dry sandblasting abrasives at least onto a surface of the insulating resin layer;
• chemically etching the surface of the insulation resin layer;
• plating a conductive layer on the surface of the insulating resin layer subjected to the chemical etching;
• and
• patterning the conductive layer into a desired pattern, thereby forming the multi-layered printed wiring board.

A method for producing a multi-layer printed wiring board, comprising the steps of:

• forming a multi-layered board by forming at least one inner circuit conductor layer on a top and bottom surface of a substrate;
• forming an insulating resin layer to cover the top and bottom surfaces of the multi-layered board;
• forming via holes in the insulating resin layer at desired positions on the multi-layered board;
• dry sandblasting abrasives at least onto a surface of the insulating resin layer and the inner faces of the via holes, thereby forming tapers at corners of the via holes;
• chemically etching the surface of the insulating resin layer;
• plating a conductive layer on the surface of the insulating resin layer and on the inner faces of the via holes;
• and
• patterning the conductive layer into a desired pattern, thereby forming the multi-layered printed wiring board.