Experimental Investigation on Buckling of Thin Films in Mechanical-Thermal Coupled-Field

The process of buckling of thin compressed films deposited on polymethylmethacrylate (PMMA) substrates under mechanical and thermal loadings has been investigated utilizing an optical microscope. Particularly, thermal cycling analysis on thin film/substrate system under compression has been characterized to discuss the thermal fatigue property of aluminum film on PMMA substrate. The influence of temperature which accords with the temperature range of the MEMS on buckling morphology has been discussed. The thermal stress caused by the mismatch in the coefficient of thermal expansion (CTE) between the film and substrate during heating process may lead to different buckling topography or induce cracking.