The characterization of thermal and elastic constants for an epoxy photoresist SU8 coating

All of the thermal and elastic constants of the high-aspect ratio, negative, UV resist, SU8 coating were carried out, and the compliance matrix of the coating was obtained. DSC, TGA, TMA, and DMTA techniques were utilized to study the thermal properties of the material. The in-plane thermal expansion coefficient (TEC) (alpha(1)) was determined by TMA, and the glass transition behavior was studied by DMTA. The TGA study provided information about the thermal stability of the material, and DSC was applied to study the thermal calorimetric properties of the material. The in-plane Young's modulus (E-1) was measured by tensile tests. The residual stresses of a 1D stretched ribbon sample and a 2D stretched membrane sample were measured by vibrational holography tests, and the in-plane Poisson's ratio (nu(1)) was also determined by holography. The out-of-plane Poisson's ratio (nu(2)) was obtained by high pressure gas dilatometry measurements. The bulk compressibility (kappa) and the volumetric TEC (alpha(v)) of the material were measured by a pressure-volume-temperature (PVT) apparatus. Finally, the out-of-plane properties, including the out-of-plane TEC (alpha(2)) and the out-of-plane Young's modulus (E-2), were calculated from the measured in-plane properties and the volumetric properties. Therefore, the compliance matrix of the studied SU8 coating could be obtained. (C) 2002 Kluwer Academic Publishers.