Metallic micro displacement capacitive sensor fabricated by laser micromachining technology

摘要

This paper presents design, fabrication and performance testing results of the micro displacement capacitive microsensor fabricated by femtosecond laser machining technology. The microsensor having overall dimensions of 1,275 (W)\ud71,153 (L) \u3bcm consisted of 20 pairs of comb fingers of 24 (W)\ud7300 (L) \u3bcm with a gap between the fingers of 6 \u3bcm, suspension springs, inertial mass and support anchors. The sensor structure was fabricated from a 25 \u3bcm thick tungsten foil. The fabricated microsensor was able to deliver 230 fF capacitance variations for measured displacements up to 25 \u3bcm. The results on the performance testing and geometry evaluation under pins the laser micromachining technology as an effective tool to fabricate miniature functional components and mechanisms. The developed microsensor can be used for micro/nano scale displacement measurements in MEMS applications.