Patent ID: 8353103
Filing Date: 2013-01-15
Classification: H01L,H05K,Y10T

Abstract:
1. A manufacturing method of a multilayer printed wiring board, the method comprising: forming a solder resist layer on the front face of a printed wiring board having a conductive circuit thereon; forming a plurality of solder pads by exposing portions of the conductive circuit through openings in the solder resist, the openings being formed by developing the solder resist or opening the solder resist with a laser; forming a mask layer on the solder resist layer and the plurality of solder pads such that the mask layer includes a non-formation portion which exposes at least one of the plurality of pads, and a formation portion which covers at least one of the plurality of pads; forming a corrosion resistant layer on the at least one of the plurality of solder pads in the non-formation portion of said mask layer, while not forming a corrosion resistant layer on the at least one of the plurality of solder pads in the formation portion of the mask layer, wherein the at least one of the plurality of solder pads in the non-formation portion has a copper surface and the corrosion resistant layer is formed directly on the copper surface; removing the mask layer to obtain a plurality of solder pads mixedly including a solder pad in which corrosion resistant layer is formed, and another solder pad in which no corrosion resistant layer is formed; and forming the OSP layer on said another solder pad in which no corrosion resistant layer is formed, after removing the mask layer, wherein: the at least one of the plurality of solder pads in the formation portion of the mask layer has a copper surface, and the OSP layer is formed directly on the copper surface.