Effects of substrate temperature on silicon nitride cracking of beam lead devices during thermocompression wobble bonding

The effects of changes in substrate temperature and force upon nitride cracking during bonding are described. Devices were bonded at 150, 200, and 250 C, and at 250 and 525 gms of force, and the amount of nitride damage in the bonding operation was determined. Neither parameter had large effects in cracking. The pulled strength and failure modes were recorded. Approximately 22 percent of the devices developed silicon nitride cracks over the beams. Total production handling and processing result in 80 to 90 percent of the devices having cracked nitride. Although the sample size is small (63 devices), it does not appear that the cracking is dependent on the substrate temperature over the range used in this evaluation.