A ceramic pin grid array package with 370 I/O leads

The scale of LSI is growing larger and larger and it's turning into complexity at present. This drive the high density package for IC to develop quickly to minimize the size and weight of electrical apparatus and improve its performance. PGA is a kind of high density packages of LSI. A ceramic pin grid array package with 370 I/O leads is developed, which is named PGA370. This package has a eight-square cavity and three-layer bonding pads. Otherwise, its pinouts are arranged in staggered array. It is designed by special CAD for PGA routing. The software is altered to meet the demand of this structure. The package has a large dimension and the insulator spacing between two neighbor pinouts is very close. Thus, it become a challenge to realize the precision dimension control of the ceramic substrate and to obtain accurate brazing on the ceramic substrate. These problems are well resolved in this research subject. Selected-gold-plating technology is successfully used in the manufacture process. The kowar rings are nickel plated and the other parts are gold plated.