Title :
Electromigration resistant alternatives to aluminum-copper
Author :
Armstrong, N.P. ; White, S.J. ; Isernhagen, R. ; Hefner, A. ; Mallardeau, C. ; Borel, G. ; Williams, H.A. ; Dulniak, R.J.
Author_Institution :
Plessey Res. Caswell Ltd., Northants, UK
Abstract :
Electromigration performance of a wide range of Al-based conductors has been investigated with two ends in view: (1) an alternative to Al/Cu without the disadvantages associated with Cu; and (2) a conductor with enhanced electromigration resistance. Al/Si/Ti or Al/Ti alloys may furnish the former, though care is required in the use of high (0.8-1%) Ti content as it leads to greatly enhanced whisker growth implying very early short-circuit failure. With system interactions or process compatibility also in view, simple two-layer and three-layer structures involving AlCu are shown to provide the optimum metal for four-layer metal at 3-4- mu m pitch, with TiW or CVD W as an underlayer, Al/Cu or possibly other alloys as main conductor, and Ti, W, or TiW as a cap. The effect of various passivation options has also been investigated. The present work was undertaken as part of the Esprit project Advanced Interconnect for VLSI.<>
Keywords :
VLSI; aluminium alloys; electromigration; failure analysis; metallisation; AlCu; AlSiTi; AlTi; Ti; TiW; VLSI; W; electromigration resistance; four-layer metal; metallisation; passivation; process compatibility; short-circuit failure; three-layer structures; two layer structure; whisker growth; Aluminum alloys; Artificial intelligence; Copper alloys; Corrosion; Current density; Electromigration; Microelectronics; Silicon alloys; Temperature; Titanium alloys;
Conference_Titel :
VLSI Multilevel Interconnection Conference, 1988. Proceedings., Fifth International IEEE
Conference_Location :
Santa Clara, CA, USA
DOI :
10.1109/VMIC.1988.14226
