Patent ID: 6933448
Filing Date: 2005-08-23
Classification: H01L,H05K,Y10T

Abstract:
1. A printed circuit board having a permanent solder mask comprising: a substrate made of a material including a first resin, said substrate having top and bottom surfaces, a first conductive pattern disposed on said top surface and having an unsheltered portion and a sheltered portion, said unsheltered portion having a base and a tip; and a first solder mask made of a second resin having a thermal expansion coefficient substantially identical to the thermal expansion coefficient of said first resin of said substrate, said first solder mask coated on said top surface to form thereon a layer having a first area and a second area, said first area having a first thickness, a smooth outer surface, and covering said sheltered portion, said second area having a second thickness less than that of said first area and surrounding said base of said unsheltered portion such that said tip of said unsheltered portion is exposed outside.