Patent ID: 8890325

Claim:
A heterojunction structure comprising: a first substrate; a second substrate comprising an electrode pad, the second substrate joined with the first substrate by an adhesive layer interposed between the first and second substrates, the first substrate and the adhesive layer having a via hole penetrating therethrough to expose a region of the electrode pad, wherein the via hole includes a first sub-via hole extending through the first substrate and having a substantially uniform first width, and wherein the via hole includes a second sub-via hole extending through a portion of the adhesive layer and having a second width greater than the first width; a connection electrode disposed, at least partially, in the via hole and contacting the electrode pad; and an organic insulation layer electrically insulating, at least in part, the connection electrode from the first substrate, wherein the first substrate has a thermal expansion coefficient different than a thermal expansion coefficient of the second substrate, and wherein the adhesive layer comprises an organic material.