CALCULATION MODEL OF THERMAL STRESSES IN SAPPHIRE - GLASS DIELECTRIC STRUCTURE FOR PRESSURE SENSOR

We describe a model for the thermal stresses calculation in sapphire - glass dielectric structure for pressure sensor using the finite element method (FEM) based on the Coventor Ware Turbo 2012 package. We use an inorganic glass dielectric of the PbO – B2O3 – ZnO system (5 μm thick) and a sapphire substrate (0.5 mm thick) obtained by the horizontal directed crystallization (HDC) method as components of the sapphire - glass dielectric structure. The model of the thermal stresses calculation in sapphire - glass dielectric structure for the pressure sensor allows defining the thermal stress values in the glass dielectric film as well as making suggestions to the developers of pressure sensors that incorporate glass dielectric as the connecting element for construction improvement. We determine the dependence of the residual thermal stresses of the glass inorganic dielectric on the sapphire substrate surface on the thickness of the dielectric film for the pressure sensor. The results of numerical simulation of thermal stresses in sapphire - glass dielectric in Coventor Ware Turbo 2012 have shown that the thermal stresses in the glass inorganic dielectric film of PbO – B2O3 – ZnO system on a sapphire substrate obtained by HDC method for a pressure sensor were in the range of 26–41 kg/cm 2 , which corresponds to theoretical calculations. The calculation results of thermal stress model for sapphire - glass dielectric structure contribute to improving the performance characteristics of the pressure sensor.