Micromachined piezoresistive tactile sensor array fabricated by bulk-etched MUMPs process

The design, fabrication and testing of a 5 5 micromachined tactile sensor array for the detection of an extremely small force (micrometer-Newton range) has been discussed. An anisotropic etching of silicon substrate of a MUMPs process chip forms a central contacting pads that are trampoline-shape suspended structures and sensor beams. A piezoresistive layer of polysilicon embedded in sensor beams is used to detect the displacement of the suspended contacting pad. Each square tactile has dimension of 200 m 200 m with 250 m center-to-center spacing. The entire sensor area is 1.25 mm 1.25 mm. The device was tested characterized under various normal force loads using weight microneedles. The individual sensor element shows the linear response to normal force with good repeatability.