Three dimensional interconnect structure and method thereof
A three-dimensional interconnect includes a first substrate bonded to a second substrate, the first substrate including a device layer and a bulk semiconductor layer, a metal pad disposed on the second substrate, an electrically insulating layer disposed between the first and second substrates. The structure has a via-hole extending through the device layer, the bulk semiconductor layer and the electrically insulating layer to the metal pad on the second substrate. The structure has a dielectric coating on a sidewall of the via-hole, and a plasma-treated region of the metal pad disposed on the second substrate. The structure includes a via metal monolithically extending from the plasma-treated region of the metal pad through the via-hole and electrically interconnecting the device layer of the first substrate to the metal pad of the second substrate.