TWI Industrial Member Report Summary 413/1990
S T Riches
There is interest in the welding of insulated Cu wire without prior removal of the insulation as an alternative to soldering and resistance heating techniques. This is of particular relevance to the welding of fine (< 100µm diameter) insulated Cu wires where difficulties are being encountered with the traditional techniques in the automation and consistency of joining to microelectronic components, eg. thick films on Al2O3. This project was set up to investigate the application of four welding techniques (ultrasonic, resistance, laser and arc spot welding) to the welding of fine insulated Cu wires of different diameters and with different insulating types to various substrates.
This report reviews the principal advantages/disadvantages of the four techniques and describes the results of welding insulated Cu wire of 25µm and 75µm diameter with various insulations (e g polyurethane, polyimide, etc) to Ag-Pd thick film on Al 2O 3, brass and to unplated Ni-Fe-Co pins.