In-situ cleaning process for Cu metallization

摘要

A new method of in-situ cleaning in a copper metallization process is described. A copper line is provided overlying a first insulating layer on a semiconductor substrate. A silicon nitride layer is deposited overlying the copper line. A second insulating layer is deposited overlying the silicon nitride layer. A via is opened through the second insulating layer to the silicon nitride layer wherein a polymer forms on the sidewalls of the via. The silicon nitride layer within the via is removed wherein the copper line underlying the silicon nitride layer is exposed within the via and whereby the exposed copper line is oxidized forming a copper oxide layer within the via. The via is cleaned within a deposition chamber wherein the cleaning comprises the following steps: first sputtering Argon into the via to remove the polymer, second pumping down the deposition chamber, and third flowing H2 and He gases into the via to reduce the copper oxide layer to copper. Thereafter, a barrier metal layer is deposited onto the third insulating layer and within the via using the same deposition chamber and maintaining vacuum. A copper layer is formed within the via overlying the barrier metal layer to complete the copper metallization in the fabrication of an integrated circuit device.