Patent ID: 6455355
Filing Date: 2002-09-24
Classification: H01L,H05K,Y02P

Abstract:
A method for mounting an exposed-pad type of semiconductor device having an exposed die pad over a printed circuit board; the printed circuit board having an upper side and a bottom side;the method comprising the steps of: (1) defining a pad-mounting area on the upper side of the printed circuit board; (2) forming a plurality of via holes in the pad-mounting area of the printed circuit board; each via hole having an upper end on the upper side of the printed circuit board and a bottom end on the bottom side of the same, and each via hole including a solder-wettable layer over the inner wall thereof; (3) pasting a solder material over the bottom end of each of the via holes; (4) mounting the semiconductor device over the upper side of the printed circuit board, with the exposed die pad thereof being abutted on the pad-mounting area of the printed circuit board; and (5) performing a solder-reflow process on the pasted solder material over the bottom end of each of the via holes so as to allow the pasted solder material to be wetted over the entire surface of each solder-wettable layer, thereby allowing the reflowed solder material to reach the upper end of each of the via holes where the reflowed solder material is further wetted to the exposed die pad of the semiconductor device, thereby bonding the semiconductor device to the printed circuit board.