Method and Structure to Improve the Conductivity of Narrow Copper Filled Vias

摘要

Techniques for improving the conductivity of copper (Cu)-filled vias are provided. In one aspect, a method of fabricating a Cu-filled via is provided. The method includes the following steps. A via is etched in a dielectric. The via is lined with a diffusion barrier. A thin ruthenium (Ru) layer is conformally deposited onto the diffusion barrier. A thin seed Cu layer is deposited on the Ru layer. A first anneal is performed to increase a grain size of the seed Cu layer. The via is filled with additional Cu. A second anneal is performed to increase the grain size of the additional Cu.

主权项

1. A copper-filled via formed in a dielectric, comprising:
a via; a diffusion barrier lining the via; a thin ruthenium layer disposed conformally on the diffusion barrier; a thin seed copper layer disposed on the ruthenium layer; and additional copper plated onto the thin seed copper layer filling the via to form the copper-filled via, wherein the additional copper has an average cross-sectional grain width of at least 0.5 times a cross-sectional width of the via.