Patent ID: 7473580

Claim:
A method of attaching a chip to a substrate, said method comprising the steps of: forming at least one substrate pad on the substrate by applying a ring of high temperature solder to said substrate to form an outer region of high temperature solder; applying low temperature solder within said outer region of high temperature solder to form an inner region of low temperature solder; placing one end of an injection molded solder column on the inner region of said substrate pad, whereby said column does not contact said outer region; mounting said chip onto an opposite end of the injection molded solder column with a C4 solder ball whereby the chip makes electrical contact with the injection molded solder column; and performing a partial reflow at a temperature between about 150° C. and 227° C. whereby said C4 solder ball wets both the inner and outer regions of the substrate pad and forms a joint between the inner region and a lower side wall of the injection molded solder column.