Fabrication of Intermetallic Diffusion Barriers for Electromigration in Narrow Line Stripes
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20
The fabrication of intermetallic compounds of Al and transition metals (HfAl(3), taAl(3), CrAl(7), TiAl(3)) for improved electromigration lifetime is described in U. S. Patent 4,017,890. The deposition process consists of layers of Al-Cu/transition metal/Al-Cu; the evaporation was completed without breaking vacuum (Fig. 1). The intermetallic compound was formed by annealing the composite structure at a temperature 350-450 degrees C. The resulting intermetallic compounds were of different thicknesses and grain structure, which was a function of the reaction rate (interdiffusion) between Al and the transition metal.