Title :
Reliability aspects of stress-induced voiding in 0.25 μm metallization
Author :
Zitzelsberger, A. ; Lehr, Malhias
Author_Institution :
Reliab. Methodology, Infineon Technol. AG, Munich, Germany
fDate :
6/21/1905 12:00:00 AM
Abstract :
Stress Void formation of Al based interconnects (0.25 μm ground rule) due to high density plasma (HDP) oxide deposition process has been reported in the literature very recently. The voids are caused by the thermal expansion mismatch between Al and oxide. It is proposed that the voiding is accelerated by the TiAl3 formation. In this paper, void formation is investigated for differently processed metal lines. Measurements include stress-migration (SM) as well as electromigration (EM) reliability tests on two types of test structures. The aim of the work was to study the influence of the stress voids on the EM performance. From reliability investigations presented in this paper it can be concluded that pre-existing voids in metal lines result only in a small decrease of electromigration median time to failure (MTF). However a decrease of the current density exponent n is found. This leads to a reduction in life time
Keywords :
aluminium alloys; copper alloys; electromigration; failure analysis; integrated circuit interconnections; integrated circuit metallisation; integrated circuit reliability; integrated circuit testing; life testing; plasma deposition; thermal expansion; titanium alloys; voids (solid); 0.25 mum; Al based interconnects; AlCuTi; TiAl3 formation; current density exponent; electromigration median time to failure; electromigration reliability tests; high density plasma oxide deposition process; metal lines; metallization; oxide; pre-existing voids; reliability; stress void formation; stress-induced voiding; stress-migration; test structures; thermal expansion mismatch; Acceleration; Current density; Electromigration; Plasma accelerators; Plasma density; Samarium; Stress measurement; Testing; Thermal expansion; Thermal stresses;
Conference_Titel :
Integrated Reliability Workshop Final Report, 1999. IEEE International
Conference_Location :
Lake Tahoe, CA
Print_ISBN :
0-7803-5649-7
DOI :
10.1109/IRWS.1999.830552
