Electromigration characteristics of vias in Ti:W/Al-Cu(2 wt.%) multilayered metallization

Author

May, Jeffrey S.

Author_Institution

Texas Instrum. Inc., Midland, TX, USA

fYear

1991

fDate

9-11 April 1991

Firstpage

91

Lastpage

96

Abstract

The electromigration (EM) performance and failure mechanisms for 1.2- mu m vias fabricated in a passivated Ti:W/Al-Cu(2 wt.%) metallization were investigated. Single van der Pauw via structures were stressed at 175 degrees C and 200 degrees C and at accelerated current densities. The via resistance was monitored independently of the metal feed lines and a difference in activation energy, failure mode, and mean time to fail was observed depending on the direction of current flow. When electrons flowed into the via, the via sustained a 20% increase in resistance before failing catastrophically. Conversely, when electrons flowed out of the via, a monotonic increase in resistance was observed, and yet the via remained intact. Concerns of poor aluminum step coverage in the vias were addressed. Reliability comparisons were made between vias and flat metal stripes.<>

Keywords

aluminium alloys; copper alloys; electromigration; metallisation; titanium alloys; tungsten alloys; 1.2 micron; 175 degC; 200 degC; TiW-AlCu; accelerated current densities; activation energy; current flow; electromigration; failure mechanisms; failure mode; flat metal stripes; multilayered metallization; resistance; step coverage; van der Pauw via structures; Aluminum; Current density; Electromigration; Electrons; Failure analysis; Feeds; Integrated circuit reliability; Metallization; Sputtering; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Reliability Physics Symposium, 1991, 29th Annual Proceedings., International

Conference_Location

Las Vegas, NV, USA

Print_ISBN

0-87942-680-2

Type

conf

DOI

10.1109/RELPHY.1991.146044

Filename

146044