METHOD TO FABRICATE COPPER WIRING STRUCTURES AND STRUCTURES FORMED THEREBY

摘要

Techniques formation of high purity copper (Cu)-filled lines and vias are provided. In one aspect, a method of fabricating lines and vias filled with high purity copper with 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 Cu layer is deposited on the Ru layer by a sputtering process. A reflow anneal is performed to eliminate voids in the lines and vias.

主权项

1. A wiring structure comprising:
a dielectric layer overlying a substrate, wherein said dielectric layer includes an opening within said dielectric layer; a diffusion barrier lining said opening; a conformal ruthenium layer on said diffusion barrier; and a void-free copper layer on said ruthenium layer, wherein said copper layer has an impurity element selected from the group consisting of Cl, S, and a combination thereof, wherein the concentration of each impurity element is less than 20 ppm.