Partial-via-first dual-damascene process with tri-layer resist approach

摘要

A partial-via-first dual-damascene method using a tri-layer resist method forms a first via hole through partial thickness of a dielectric layer, and forms a tri-layer resist structure on the dielectric layer to fill the first via hole with the bottom photoresist layer. A dry development process is performed to transfer a first opening on the top photoresist layer to the middle layer and the bottom photoresist layer, and expose the first via hole again, and remove the top photoresist layer. A dry etching process is then performed to form a second via hole under the first via hole and a trench over the second via hole. Finally a wet striping process is used to remove the remainder of the photoresist layer.