Title :
Stacked film structured dependence of electromigration in Al-Cu interconnect terminated with W plug
Author :
Matsumoto, S. ; Etoh, R. ; Ohtsuka, T. ; Kouzaki, T. ; Ogawa, S.
Author_Institution :
Matsushita Electron. Corp., Kyoto, Japan
Abstract :
We have investigated the stacked film structure dependence of the electromigration (EM) lifetime in AlCu interconnects terminated with W-plugs, the structures of which are Ti-TiN-AlCu-TiN, Ti-AlCu-TiN, and Ti-AlCu-Ti-TiN. It has been clarified that the dependence is caused by the difference in the time to deplete Cu atoms over a critical length. We found that the difference is caused by a reduction in the cross-section of the AlCu portion and the reduced Cu concentration in the AlCu portion which is induced by Al3Ti formation. In addition, the difference is also caused by the increase in the interface between Al3Ti and AlCu, which is the dominant Cu diffusion path
Keywords :
aluminium alloys; chemical interdiffusion; copper alloys; diffusion barriers; electromigration; integrated circuit interconnections; integrated circuit metallisation; integrated circuit reliability; integrated circuit testing; interface structure; surface chemistry; tungsten; Al3Ti formation; Al3Ti-AlCu; Al3Ti-AlCu interface; AlCu interconnects; AlCu portion cross-section; AlCu-W; Cu atom depletion; Cu concentration; Ti-AlCu-Ti-TiN; Ti-AlCu-Ti-TiN stack; Ti-AlCu-TiN; Ti-AlCu-TiN stack; Ti-TiN-AlCu-TiN; Ti-TiN-AlCu-TiN stack; W plug termination; critical length; dominant Cu diffusion path; electromigration; electromigration lifetime; stacked film structure dependence; Current density; Electromigration; Grain size; Optical films; Plasma temperature; Plugs; Probability distribution; Spectroscopy; Testing; Tin;
Conference_Titel :
Interconnect Technology Conference, 1998. Proceedings of the IEEE 1998 International
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-4285-2
DOI :
10.1109/IITC.1998.704766
