Abstract
This study presents a flip-chip integrated CMOS chip with polymer-filler and metal-ball in backside Si cavity for inductive tactile sensor (Figs. 1a-b). By using the polymer-filler and chrome-steel ball as force/sensing interface, the proposed inductive tactile sensor has several merits: (1) cavity on backside Si-substrate for polymer molding and chrome-steel ball housing, (2) dual-stage polymer molding to define polymer-spring and to fix the chrome-steel ball, (3) flip-chip bonding to replace the wire bonding for the electrical connection, and (4) sensing-chip backside loading design for flip-chip bonding. The presented design is implemented using the standard TSMC 0.35mumathrm{m} 2P4M CMOS process and in-house post-CMOS processes. Measurements indicate the sensitivity of tactile sensor is 3.2nH/N within loading range of 0-2N, and the monolithically integrated thermometer with TCR of 0.1%/°C is also demonstrated.