Ultrasonic welding of copper to laminate circuit board

by Tucker, Joseph C.

The ultrasonic welding of Cu110, electrolytic tough pitch copper sheet to electroless plated laminate circuit board was experimentally investigated within the range of 20 kHz. The effects of machine parameters; energy, amplitude and pressure as well as material characteristics such as surface roughness, gauge, temper, and silver and gold plating schemes were compared through pull tests and analysis of microstructure. Evidence was discovered which attributes plastic deformation, mechanical interlocking, and acoustic softening to the mechanism of weld formation. It was further determined that ultrasonic welding of Cu110 sheet to silver immersion laminate circuit boards as means of electrical termination is a robust process. Therefore it was the goal of this thesis to understand the mechanism of ultrasonic welding and determine if ultrasonic welding to laminate circuit boards is an alternative to soldering electrical terminations. iii