Thermal laser micro-adjustment using ultra-short pulses

MEMS manufacturing requires accurate positioning and high reproducibility. Lasers can be utilised in accurate post-fabrication adjustment, allowing for manufacturing processes with relatively large tolerances. Laser micro forming (L?F) is a process for the precision adjustment, shaping or correction of distortion in micro-scale metallic components through the application of laser irradiation without the need for permanent dies or tools. The non-contact nature of the process is also useful in accessing specific micro-components within a device which may be highly sensitive to mechanical force. As such it has potential for widespread application in both the manufacturing and microelectronics industry. In this work, the micro-adjustment of 1000 x 300 ?m stainless steel actuator arms using a mode locked fibre laser with a maximum pulse energy and duration of 3 ?J and 20 ps respectively was conducted. The effect of pulse overlap, laser power, irradiation strategy and number of irradiations on the net bend angle is presented. In addition, the mechanism of thermal deformation was investigated through numerical modeling and the potential for its application in the micro-adjustment of MEMS scale components discussed.