Leak detection methods for glass capped and polymer sealed MEMS packaging

This paper presents the limitations of the helium leak test when applied to typical MEMS packages. A novel closed-form expression is presented which allows the determination of the minimum cavity volume package that can be accurately tested using the helium leak test method in conjunction with a standard gross leak test. This expression can be used to find optimum test parameters for packages with cavity volumes greater than 2.6 x 10(-3) cm(3). Hermeticity testing using FTIR and Raman spectroscopy are considered as potential methods to overcome the limitations of the helium leak test method.