USING MILLISECOND PULSED LASER WELDING IN MEMS PACKAGING

摘要

A new packaging method for a wide range of MEMS for application on both the wafer and device scale. Titanium is used as the packaging material and both silicon and titanium MEMS devices are integrated on to a titanium substrate. A Nd:YAG pulsed laser is used to micro-weld the titanium cap to the substrate. A three-dimensional time dependent model of heat flow during laser beam welding is presented. The heat transfer and parametric design capabilities of COMSOL were employed for this purpose. Model calculations are compared and calibrated with experimental results of pulsed laser welds. The functionality and hermiticity of the proposed packaging was evaluated by packaging a self actuated Veeco Instrument AFM cantilever tip. The experimental measurements show that the resonance frequency and quality factor of the device stay the same before and after packaging and the applied technique has no effect on the device.