Process alternatives and scaling limits for high-density silicon tactile imagers

Abstract

In this paper the process complexities and parasitic substrate coupling effects are compared for several different high-density capacitive tactile imagers. The dissolved-wafer process using diffused bulk-silicon row lines and metal-on-glass columns is found to offer the simplest process and fastest response, requiring only five non-critical masks and producing a settling time for the column charge of about 1 [mu]s. Using this process, a 1024-element array with a force range of 1 gm and a spatial resolution of 500 [mu]m produces a force resolution equivalent to seven bits. Scaled to a 4096-element array, this same process should produce a force resolution of nearly six bits for the same force range and a spatial resolution of 250 [mu]m.