This document discloses techniques, apparatuses, and systems for a semiconductor device with a polymer layer. A semiconductor assembly is described that includes two semiconductor dies. The first semiconductor die has a first active side with first circuitry and a first back side opposite the first active side. Contact pads and a layer of polymer material are disposed at the first back side such that the layer of polymer material includes openings that expose the contact pads. The second semiconductor die has second circuitry disposed at a second active side. Interconnect structures are also disposed at the second active side such that the interconnect structures extend into the openings and couple to contact pads. A passivation layer (e.g., dielectric material) is disposed at the second active side and directly bonded to the layer of polymer material to reliably couple the two semiconductor dies.