Research of wire bonding technology in a stacked die package based on orthogonal test

0.203 2 mm(8 mil) Au wire was used as the bonding wire,series of orthogonal tests such as the ball formation, the pull test, and the wire tail test were performed by ultrasonic thermo compression bonding process. The effects of wire bonding parameters on the bonding qualities were systematically analyzed. Results show that the optimized process parameter windows are bonding temperature is 180 ℃ or 190 ℃, bonding power is 35 mW, bonding time is 15 ms or 20 ms, bonding pressure is 0.12 N, electronic flame off current is 3 200 mA, electronic flame off time is 350 μs and tail wire length is 20 μm. In various factors affecting the wire bonding quality, bonding power and bonding pressure have a significant influence on bonding qualities. Results show that the bonding areas could be damaged by too high bonding power and the wire bonding strength reduces. Defective bonding could be caused by too small bonding power. The bonding ball deformation could be caused by too large bonding pressure and the bonding strength is also reduced by too small bonding pressure.