Characterization of the thermosonic wire bonding technique

A combination of ultrasonic energy and thermocompression techniques was evaluated with regard to the bond response of thin film substrate metallization and thick film discrete component terminations for microcircuits. The object was to determine not only the quality of thermosonic gold wire bonds and the performance of these bonds when subjected to thermal environmental tests, but also to determine the process control parameters necessary to produce repeatable, reliable bonds. Comparison was made throughout the study with regard to results previously achieved on the same metallization systems using standard fine wire thermocompression bonding techniques. It is concluded that the thermosonic wire bonding technique offered the advantages of lower bonding forces and lower substrate temperatures compared to the thermocompression process. In addition, it is shown that the thermosonic technique eliminates the need for special pre-bond etching and cleaning procedures presently used in production of Sandia hybrid microcircuits.