Numerical analysis of the interfacial contact process in wire thermocompression bonding

Wire deformation processes during thermocompression bonding without ultrasonic vibration are represented by a numerical model which is based on the finite-element method. The growth process of interfacial contact between the wire surface and lead frame is also studied. Findings indicate that a wire reduction greater than 0.5 is needed for a strong perimeter bond formation. The interfacial contact area is affected mainly by the wire reduction.