Expansion controlled structure for direct bonding and method of forming same

Abstract

An element, a bonded structure including the element, and a method forming the element and the bonded structure are disclosed. The element can include a non-conductive region having a cavity. The element can include a conductive feature formed in the cavity. The conductive feature includes a center portion and an edge portion having first and second coefficients of thermal expansion respectively. The center and edge portions are recessed relative to a contact surface of the non-conductive region by a first depth and a second depth respectively. The first coefficient of thermal expansion can be at least 5% greater than the second coefficient of thermal expansion. The bonded structure can include the element and a second element having a second non-conductive region and a second conductive feature. A conductive interface between the first and second conductive features has a center region and an edge region. In a side cross-section of the bonded structure, there are more voids at or near the edge region than at or near the center region.

Dependencies are inferred from the claim text.