Metallurgical reactions at the interface of Sn/Pb solder and electroless copper-plated AlN substrate

Intermetallic formation between electroless-plated copper and Sn/Pb solder is investigated. An interlayer is formed between copper and solder, and segregation of Pb-rich and Sn-rich phases are observed. X-ray diffraction and EDX analysis results suggest that the major intermetallic formed in the interlayer is Cu/sub 6/Sn/sub 5/. For the as-plated sample, the adhesion strength of Cu to the AIN substrate after 150/spl deg/C aging is affected by both the recrystallization and the creep of copper. For the soldered specimen, the presence of intermetallic compound causes cracks to propagate along the intermetallic/Cu interface and results in a decrease of the adhesion strength.<
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