Effects of substrate temperature on silicon nitride cracking of beam lead devices during thermocompression wobble bonding [electronic resource].
- Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 1976.
- Additional Creators:
- United States. Department of Energy. Office of Scientific and Technical Information
- Recent failures in several completed Sandia Laboratories' electronic systems have traced to specific format 25 beam lead transistors and diodes. More extensive failure analysis on the devices showed them to exceed their respective specifications in electrical leakage. All of the failed devices were observed to have one thing in common: cracked silicon nitride over the beams. These observations triggered several investigations to determine if cracked silicon nitride causes electrical failures, where (processing, assembly, etc.) nitride cracking occurs, and when nitride cracking can be reduced or eliminated. The effects of changes in substrate temperature and force upon nitride cracking during bonding are described. Devices were bonded at 150, 200, and 250/sup 0/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. The results showed that 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. The high level of nitride cracking in production must be caused by other production processes or by a difference in the bonding conditions for production as compared to the bonding done for this evaluation.
- Published through SciTech Connect.
Bushmire, D.W.; Chavez, E.L.; Finley, M.H.
Sandia Labs., Albuquerque, N.Mex. (USA)
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