Thermocompression bonding of external package leads on integrated circuit substrates

A new technique for attaching external package leads to metallized substrates is presented. Gold-plated copper lead frames and gold-plated headed leads of various compositions are thermocompression bonded to metallized alumina substrates. The generated patterns on the substrates consist of an evaporated layer of gold over an evaporated layer of titanium. The leads are bonded simultaneously to form gold diffusion bonds between the leads and the metallized substrate. The lead frames are stamped from 0.005" and 0.10" thick copper. The headed leads range in size from 0.016" diameter to 0.025" square. The various problems encountered in the development of this technique and their related solutions will be discussed.