Thermomechanical properties and moisture uptake characteristics of hydrogen silsesquioxane submicron films

This letter describes measurement of the biaxial modulus, coefficient of thermal expansion (CTE), and moisture uptake characteristics of hydrogen silsesquioxane (HSQ) thin films. The biaxial modulus and CTE were determined using a bending beam method, and moisture uptake was studied using a quartz crystal microbalance method. The biaxial modulus and CTE of a 0.5 μm HSQ film were measured on Si and Ge substrates and found to be 7.07 GPa and 20.5 ppm/°C, respectively. The value determined for the diffusion constant of water in a 0.7-μm-thick HSQ films is 3.61×10−10 cm2/s at room temperature.