Title :
The influence of stud bumping stress on device degradation in scaled MOSFETs
Author :
Shimoyama, Nobuhiro ; Machida, Katsuyuki ; Shimaya, Masakazu ; Koizumi, Hiroshi ; Kyuragi, Hakaru
Author_Institution :
NTT Syst. Electron. Labs., Kanagawa, Japan
Abstract :
This paper presents the effect of area bumping on device degradation in scaled MOSFETs. We have investigated the gate channel length dependence of transconductance (gm) degradation after stud bumping above the MOSFETs and changes in the charge pumping currents for those devices. The von Mises equivalent stress is used to simulate the distribution of mechanical stress at the gate edges. From the relationship between the von Mises equivalent stress distribution and the change in the charge pumping currents after stud bumping, we show that stress concentrates within 0.1 μm of the gate edges. Furthermore, by estimating the amount of increased interface-state density, we predicted that stud bumping stress greatly influences the device degradation of scaled MOS devices
Keywords :
MOSFET; electric current; electronic density of states; integrated circuit design; integrated circuit interconnections; interface states; internal stresses; semiconductor device metallisation; semiconductor device reliability; semiconductor device testing; stress analysis; MOSFETs; area bumping; charge pumping currents; device degradation; gate channel length; gate edge mechanical stress distribution; interface-state density; scaled MOS devices; scaled MOSFETs; stress concentration; stud bumping; stud bumping stress; transconductance degradation; von Mises equivalent stress; von Mises equivalent stress distribution; Aluminum; Bonding; Charge pumps; Degradation; Gold; MOS devices; MOSFETs; Pulse measurements; Stress; Wire;
Conference_Titel :
Reliability Physics Symposium Proceedings, 1999. 37th Annual. 1999 IEEE International
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-5220-3
DOI :
10.1109/RELPHY.1999.761589
