A very high density bulk micromachined capacitive tactile imager

This paper reports the design and fabrication of very high density planar capacitive tactile imagers intended for eventual use in live-scan fingerprinting. Prototype 16/spl times/16-element arrays have been fabricated with both 300 dots-per-inch (dpi) and 500 dpi spatial resolution. Each pixel is formed by the intersection of metal column lines on glass and p/sup +/ silicon row electrodes that are suspended by dual angular beams. Fabrication is achieved using a simple 7-mask high-yield dissolved-wafer process. The 300 dpi and 500 dpi tactile imagers have a force sensitivity of 150 N/m and 90 N/m, respectively; this can be easily adjusted by varying the beam thicknesses.