TEMPERATURE CYCLING EFFECTS BETWEEN SN PB SOLDER AND ELECTROLESS COPPER PLATED AIN SUBSTRATE/

Thermal cycling effects on Sn/Pb solder and electroless Cu-plated AIN substrates are investigated. X-ray diffraction patterns reveal the exi stence of Cu2O for the electroless Cu-plated AIN after thermal cycling in an environmental chamber. Moisture in the chamber results in the o xidation of electroless plated Cu and fracture takes place at the Cu2O /Cu interface. The oxidation of Cu is also confirmed by Auger depth pr ofile and electrical sheet resistance measurement. For the solder/Cu/A IN system, fracture occurs at the Cu/solder interface. No intermetalli c compounds between solder and Cu are found after thermal cycling. Str ess resulting from the thermal expansion mismatch is the major cause o f loss of adhesion.