Temperature cycling effects between Sn/Pb solder and electroless copper plated AIN substrate

Abstract

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