Employing coherent detection for on-chip six-axis position sensors

Recent interest in multi-chip integration has motivated the development of on-chip sensors to address alignment challenges of assembling complex multi-chip packages. Earlier sensor implementations were susceptible to transistor leakage currents. More recent demonstrations correct this issue by measuring differences in coupling capacitances and using coherent detection to lower the noise floor. In this paper, we discuss these mechanisms that improve the accuracy of on-chip position sensors. We also present new methods of determining chip separation that can leverage coherent detection by measuring only differences in coupling.