The accurate value of thermal expansion coefficient (a) of thin film is an important thermal property in the design of microelectronic devices and microsystem. This research presents a microbridge buckling deformation caused by the residual stresses to determine the (a) of thermal oxide (SiO2) film. The extraction of (a) is supported through experimental means and finite element analysis (FEM) of the buckling profiles of microbridge. Moreover, in order to obtain the (a) value of thermal SiO2 film in accuracy, the nanoindentation system and the optical microscope with high resolution gauge were used to determine the elastic modulus of thermal SiO2 film and the (a) of silicon substrate, respectively. After experimental and FEM using thermal mechanical analysis approaches, the (a) value of thermal SiO2 film was calculated. Measurement value presents here for (a) of thermal SiO2 film was 0.24_10-6/_ with a standard deviation of 0.02_10-6/_. More importantly, the measurement mechanism presented here can be also applied to the measurement of other thin film materials, but, only on the condition that it must be limited with a compressive prestress and its stress value must large enough to cause the suspension microstructure with a large out-of-plane deformation.
Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2005 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: May 8, 2005
Pages: 339 - 342
Industry sector: Sensors, MEMS, Electronics
Topic: Modeling & Simulation of Microsystems