On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes

Review of the Techniques to Measure the Hermeticity of Glass Frit Encapsulated Solar Cells

“…The helium leak rate test is not adequate for very small volume packages. Several authors already discussed the applicability of the helium leak rate test for testing low volume cavities and concluded that false positive results can occur (Tao and Malshe 2005; Goswami and Han 2008;Costello, Desmulliez, and McCracken 2012). The applicability of this test is further conditioned by the strength of the devices to endure the pressure difference that are submitted during bombing and measuring phase.…”

Analytical investigation of the feasibility of sacrificial microchannel sealing for Chip-Scale Atomic Magnetometers

“…3. Inert gases are filled into the vapor cell through the microchannels by surrounding the vapor cell with gases, which is called "bombing" (Goswami et al 2008). In the estimation, filling pressure was an absolute pressure of 0.25 MPa, and bombing pressure was an absolute pressure of 0.3 MPa.…”

Measurements of True Leak Rates of MEMS Packages

“…The method utilizes the complete profile of the apparent leak rate collected by the mass spectrometer and determines the true leak rate by performing a non-linear regression analysis. The theoretical limit of true leak rates that can be measured by the fine leak test was studied previously [ 11 , 12 ]. The theory and the procedure to extract the true leak rates in this measurable range will be presented in the following sections.…”

“…, the actual signal. In practice, however, a small amount of helium present in ambient air contributes to the signal in the form of noise [ 11 , 12 ]. This extra signal is called the “ zero signal ”.…”