Application of YAG Pulsed Laser Micro-Welding in MEMS Packaging

This paper reports 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 in this work 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 were compared and calibrated with experimental results of pulsed laser welds. The proposed technique is applied to package an 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.