Sacrificial Microchannel Sealing by Glass-Frit Reflow for Chip Scale Atomic Magnetometer

Abstract

A novel sealing technique using sacrificial microchannels was proposed for atmosphere control in a micromachined alkali gas-filled cell for a chip scale atomic magnetometer. The microchannels act as feedthrough connecting the cell to outside atmosphere during evacuation and gas-filling steps, and eventually they are sealed by glass-frit reflow. Si microchannel dedicated as a sacrificial microchannel was proposed and its feasibility was successfully demonstrated by experiments. The simulation results clarified the glass-frit reflow characteristics and its dependence on cross-sectional shape of the microchannel. Hermeticity of the proposed sealing technique of less than 10^-12Pa·m³/s leak rate was verified by a high resolution helium leak test.