Cr–Cu and Cr–Cu–Cr Thin Film Metallization

Abstract

Thin film sandwiches of Cr–Cu and Cr–Cu–Cr are widely used for a number of electronic applications, but there has been no report of any systematic investigation of interactions or stability in these films. We have studied diffusion, oxidation, and stability in these films using resistometric techniques and electron diffraction and have found that these systems are useful only at low temperature (< 175°C) in oxidizing environments. At high temperatures in any environment, oxidation and diffusion result in many problems: resistivity instabilities, oxidation, hardening (bonding problems), variable solderability, and extreme difficulty in dielectric overcoating. Techniques are discussed to circumvent some of these problems.