A dry wafer-reconstitution process with zero insertion force by embedded alignment guide tabs

Abstract

We demonstrate embedding of chiplets into wafers to bypass the monolithic integration challenges of combining micro-mechanical devices with active circuitry. Dry alignment is provided by passive guide tabs, which are created through polysilicon refill of frontside etched trenches. The guide tabs are compatible with further processing on the wafer. Precision chiplets are created by through-wafer etching. After chiplet drop-in, optical detection provides feedback of chiplet jamming, and horizontal driving of the chiplets finishes the zero insertion force assembly process. We demonstrate less than 2.5 µm of chiplet to substrate alignment error. Theoretical scaling of alignment accuracy reaches numbers comparable to photolithography, allowing high density interconnects for heterogeneous integration without precision manipulators.