Evaluation of the mechanical properties of thin metal films

The nano-indentation method has been developed to evaluate the mechanical p roperties of metal films. In this study an indentation loading curve is emp loyed to determine the yield strength and hardening index of an Al film on a Si substrate. The result is compared with that measured by a uniaxial ten sile test with an Al film deposited on an Al foil. The yield strength of th e Al film can be determined according to the testing results of this compou nd material and it agrees reasonably with that evaluated by the nano-indent ation method. In addition, X-ray diffraction measurements of the four point bending specimen is used to measure the stress-strain curve of Cu films on steel substrate. The samples are prepared by ion beam enhanced deposition and magnetron-sputtering deposition. The results show that the strength of Cu film depends on the deposition technology and is much higher than that o f the bulk material. (C) 1999 Elsevier Science S.A. All rights reserved.