Patent ID: 6278180
Filing Date: 2001-08-21
Classification: H01L,H05K,Y02P

Abstract:
A ball grid array type semiconductor device including a package substrate consisting of a ceramic printed wiring board with a semiconductor chip mounting portion on the main side thereof and electrodes arranged in an array on the back side thereof a semiconductor chip fixed on the main side of the package substrate, a connecting means for electrically connecting the electrodes of the semiconductor chip and the wiring of the package substrate, a sealing body consisting of an insulating resin and provided on the main side of the package substrate for covering the semiconductor chip and the connecting means, a buffer layer consisting of high-melting point solder and provided on the electrodes, and metal balls fixed on the buffer layer via a pedestal layer consisting of low-melting point solder, the package substrate being formed of a low temperature sintered glass ceramic multilayer substrate, the buffer layer coating the entire surface of the electrodes with its periphery portion extended a prescribed distance to the back side of the package substrate, the overall size of the buffer layer being larger than that of the pedestal layer, the diameter of the metal-balls being smaller than the overall size of the pedestal layer, and the pedestal layer has a circular arc cross-section such that the diameter of the pedestal layer is larger in a junction with the buffer layer than that in a junction with the metal ball, and the peripheral contour is concurred in the intermediate portion thereof.