Abstract
This study extends the approach in [1] by applying the Halbach array concept to arrange and integrate 5 sensing units (including 1 center unit and 4 corner units), each unit consisting of planar and vertical inductive coils (Fig. 1a), on a CMOS chip to implement a three-axis inductive tactile sensor (Fig. 1b). The coil design with the arrangement of Halbach array could converge the magnetic flux between units up to the top surface of the device to enhance the performance of the inductive tactile sensor. By leveraging the multiple metal layers of the TSMC 0.18μm 1P6M standard CMOS process platform in this study, the vertical and the planar coils are fabricated and integrated to realize the proposed design. Measurements reveal that the sensitivity of the force sensor with proposed three-dimensional coils has been improved by 2-fold for normal load and 2.4-fold for shear load.