Precise-Aligned Lock-And-Key Bonding Structures

摘要

Copper (Cu)-to-Cu bonding techniques are provided. In one aspect, a bonding method is provided. The method includes the following steps. A first bonding structure is provided having at least one copper pad embedded in a first insulator and at least one via in the first insulator over the copper pad, wherein the via has tapered sidewalls. A second bonding structure is provided having at least one copper stud embedded in a second insulator, wherein a portion of the copper stud is exposed for bonding and has a domed shape. The first bonding structure is bonded to the second bonding structure by way of a copper-to-copper bonding between the copper pad and the copper stud, wherein the via and the copper stud fit together like a lock-and-key. A bonded structure is also provided.