US Patent 7960210 Ultra-thin chip packaging

A packaging method involves attaching a first chip to a stable base, forming contact pads at locations on the stable base, applying a medium onto the stable base such that it electrically insulates sides of the first chip, forming electrical paths on the medium, attaching a second chip to the first chip to form an assembly, and removing the stable base. A package has at least two chips electrically connected to each other, at least one contact pad, an electrically conductive path extending from the contact pad to a contact point on at least one of the chips, a planarizing medium, and a coating material on top of the planarizing medium.