Simulation of encapsulation stress in a micromachined silicon membrane pump

The encapsulation stress induced on a micromachined silicon membrane pump encapsulated in plastic is quantified. A combination of numerical and analytical techniques are used to deduce limits for the maximum permissible diemensions of a membrane subject to encapsulation stresses. The approach uses finite element techniques to estimate the membrane stress due to packaging followed by an elastic stability theory approach to determining the critical buckling load for a biaxially loaded plate.