AbstractA laser based surface scanning technique was utilized to measure the polyimide coated silicon wafer curvature resulting from thermal cycling and mismatch, Meanwhile, mechanical properties of polyimide thin film were characterized by DMA, TMA and tensile test. Based on the obtained material properties, A FEA model was developed to analyze the experimental results -reasonable correlation was obtained.Similar approaches were taken one step further in the MCM silicon substrate curvature measurement. In a MCM package with silicon substrate, epoxy adhesive, and ceramic package, substrate warpage was developed in a thermal cycle due to thermal mismatch between the substrate and the package and coupling effect linked by epoxy adhesive. Three different substrate curvature measurement techniques were applied to identify the substrate curvature and epoxy thin film properties were also well characterized. A 3D FEA model incorporating with the epoxy material properties was developed to analyze the substrate warpage and investigate an optimal package design.
Intermodal interferometer for strain and temperature sensing fabricated in birefringent boron doped microstructured fiber
