Micro grid array solder interconnection structure for second level packaging joining a module and a printed circuit board

The present invention relates to interconnection structures for joining an electronic array module to a printed circuit board or card, and more particularly to a structure for forming solder interconnection joints that exhibit reduced stress resulting from thermal mismatch of the module and the printed circuit board. The present invention is especially suitable in providing micro ball grid arrays ( BGA). The present invention is also concerned with the method for fabricating such interconnection structures. A solder interconnection between a module and printed circuit board or card is provided by a plurality of solder connections arranged in a micro grid array joining solder wettable pads on a major surface of the module to a corresponding set of solder wettable pads of the printed circuit board or card. The solder connections are column shaped with the height of each connection being at least about 1.4 times the diameter of the connection.