Title :
A new analysis of stress relaxation phenomena for stress-migration tolerance estimation
Author :
Kawano, Y. ; Ohta, T.
Author_Institution :
LSI Div., Kawasaki Steel Corp., Chiba, Japan
Abstract :
Stress relaxation phenomena during SM life test was analyzed using a creep constitutive equation. The deviator stress rather than previously proposed axial stress or hydrostatic stress was demonstrated to be the most suitable parameter to explain the stress relaxation. The activation energy Q and the creep exponent n were determined for AlSi (Q=0.07 eV, n=2.8), AlCu (Q=0.23-0.27 eV, n=4.8) and TiN/AlCu/TiN (Q=0.27 eV) lines. The time to degradation of the deviator stress calculated by this equation correlated well with SM failures over a wide variety of wirings, and proved to be a useful characteristic index to estimate SM tolerance.
Keywords :
VLSI; aluminium alloys; copper alloys; creep; electromigration; failure analysis; integrated circuit metallisation; integrated circuit reliability; integrated circuit testing; life testing; silicon alloys; stress relaxation; titanium compounds; AlCu; AlCu lines; AlSi; AlSi lines; SM failures; TiN-AlCu-TiN; TiN/AlCu/TiN lines; VLSI metallization; X-ray stress measurement; activation energy; creep constitutive equation; creep exponent; deviator stress; life test; stress relaxation phenomena; stress-migration tolerance estimation; time to degradation; Creep; Equations; Life estimation; Life testing; Passivation; Samarium; Temperature; Thermal stresses; Tin; Wiring;
Conference_Titel :
Reliability Physics Symposium, 1995. 33rd Annual Proceedings., IEEE International
Conference_Location :
Las Vegas, NV
Print_ISBN :
0-7803-2031-X
DOI :
10.1109/RELPHY.1995.513702
