Interconnection process for module assembly and rework

摘要

An interconnection structure and methods for making and detaching the same are presented for column and ball grid array (CGA and BGA) structures by using a transient solder paste on the electronic module side of the interconnection that includes fine metal powder additives to increase the melting point of the solder bond. The metal powder additives change the composition of the solder bond such that the transient melting solder composition does not completely melt at temperatures below +230° C. and detach from the electronic module during subsequent ref lows. A Pb-Sn eutectic with a lower melting point is used on the opposite end of the interconnection structure.In the first method a transient melting solder paste is applied to the I/O pad of an electronic module by means of a screening mask. Interconnect structures are then bonded to the I/O pad.In a second method, solder preforms in a composition of the transient melting solder paste are wetted onto electronic module I/O pads and interconnect columns or balls are then bonded.Detachment of an electronic module from a circuit card can then be performed by heating the circuit card assembly to a temperature above the eutectic solder melting point, but below the transient solder joint melting point.