STRESS-RELAXATION IN AL(CU) THIN-FILMS

Substrate curvature measurements were used to study both the stress ch anges during thermal cycling and the kinetics of tensile stress relaxa tion in 800 nm Al (0.5wt% Cu)-films on oxidized Si-substrates. Qualita tive microstructural evidence is provided for the observed decrease in room-temperature stress after the first and subsequent thermal cycles . Isothermal relaxation measurements at temperatures up to 100 degrees C could be described well by dislocation glide with an activation ene rgy of 3.0 +/- 0.3 eV and an average athermal flow stress of 600 +/- 2 00 MPa. Evidence for an Orowan-strengthening mechanism is provided by TEM-investigation.