Low stress direct hybrid bonding

Abstract

Methods for fabrication dielectric layers having conductive contact pads, and directly bonding the dielectric and conductive bonding surfaces of the dielectric layers. In some aspects, the method includes disposing a polish stop layer on dielectric bonding surfaces on top of a dielectric layer. A conductive layer is disposed on top of the polish stop layer and then polished to form conductive contact pads having polished conducting bonding surfaces. During the polishing process, the polish stop layer reduces rounding of dielectric edges and erosion of the dielectric bonding surfaces between closely spaced conductive bonding surfaces. The resulting polished dielectric and conductive bonding surfaces are directly bonded to dielectric and conductive bonding surfaces of another dielectric layer to form conductive interconnects.