Thin copper films have been passivated by exposure to a dilute silane mixture (2% SiH4/Ar) at temperatures in the range of 225 - 375 °C. Previous XRD characterization indicates the surface layer to be Cu5Si[l]. Subsequently, the growth kinetics were examined by sheet resistance (Rs), RBS and step height measurements. Two distinct growth regimes are observed. The flow rate and time dependencies of the low temperature growth indicate parabolic solid state diffusion limited growth. The corresponding activation energy is 0.7 eV. A mass transport limitation is evidenced at higher temperatures. In addition, the biaxial stress and adhesion responses have been observed using the substrate curvature technique and scotch tape peel tests, respectively. A biaxial modulus (Eb) of 2.9x1011 Pa and coefficient of thermal expansion (CTE) of 8.6xl0-6 /°C have been determined from stress temperature cycling on Si and a-quartz substrates.