Journal of Materials Research


Adhesion and reliability of copper interconnects with Ta and TaN barrier layers

Michael Lanea1, Reinhold H. Dauskardta1, Nety Krishnaa2 and Imran Hashima2

a1 Department of Materials Science and Engineering, Stanford University, Stanford, California 94305-2205

a2 Applied Materials Corporation, Santa Clara, California 95052

With the advent of copper metallization in interconnect structures, new barrier layers are required to prevent copper diffusion into adjacent dielectrics and the underlying silicon. The barrier must also provide adequate adhesion to both the dielectric and copper. While Ta and TaN barrier layers have been incorporated for these purposes in copper metallization schemes, little quantitative data exist on their adhesive properties. In this study, the critical interface fracture energy and the subcritical debonding behavior of ion-metal-plasma sputtered Ta and TaN barrier layers in Cu interconnect structures were investigated. Specifically, the effects of interfacial chemistry, Cu layer thickness, and oxide type were examined. Behavior is rationalized in terms of relevant reactions at the barrier/dielectric interface and plasticity in adjacent metal layers.

(Received August 20 1999)

(Accepted October 25 1999)