Fabrication of MEMS cantilever using laser micromachine

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This paper presents the fabrication of MEMS cantilever using laser micromachine. This technique of micromachining is able to overcome the problem limitations of conventional lithography. It also facilitates three-dimensional (3D) microfabrication rather than two dimensional (2D) microfabrication of conventional lithography. Prior to fabrication process, wet etching process using KOH solution are carried out on silicon wafer. Etching process is necessary to thin the silicon wafer for the laser micromachine purpose. The etch performance on silicon wafer was investigated by varying the concentration of potassium hydroxide (KOH) solution with respect to time. It can be seen that with higher KOH concentration and higher KOH solution temperature, the etch rate is higher and it will thin the silicon wafer faster. Even though it is beneficial when the time taken for the etching process is faster, this also resulted in a rougher wafer surface. The optimized etch rate is approximately l μm/min which yield in low surface roughness. The optimized parameters of laser micromachining were implemented to produce MEMS cantilever. Silicon wafer is used because most of the MEMS devices are silicon-based substrate. Three types of microcantilever were fabricated using laser micromachine namely rectangular cantilever, T-shaped cantilever and triangular microcantilever. Scanning electron microscope (SEM) and high power microscope (HPM) were used to obtain the surface morphology on the ablated area of the microcantilevers.