PLANAR COPPER PLATING AND ELECTROPOLISHING TECHNIQUES

• Published in: Chemical engineering communications 2006-07, Vol.193 (7), p.903-915
• Main Authors: BaŞol, B. M., Uzoh, C. E., Talieh, H., Wang, T., Guo, G., Erdemli, S., Cornejo, M., Bogart, J., Basol, E. C.
• Format: Article
• Language: English
• Subjects: Copper; Electroplating; Electropolishing
• ISSN: 0098-6445; 1563-5201
• DOI: 10.1080/00986440500267410

Electrochemical mechanical deposition (ECMD) is a novel technique that has the ability to deposit planar conductive films on non planar substrate surfaces. This technique involves electrochemical deposition (ECD) while simultaneously polishing the substrate surface. Preferential deposition of the conductor into the cavities on the substrate surface may be achieved through two different mechanisms. The first mechanism is more mechanical in nature and it involves material removal from the top surface. The second mechanism is more chemical in nature, and it involves enhancing the deposition into the cavities where mechanical sweeping does not reach and reducing deposition onto surfaces that are swept. In this study we demonstrate that in an ECMD process, low-pressure mechanical sweeping of the wafer surface during copper plating can establish a differential in the activity of the organic accelerator species between the surface and the cavity regions of the substrate and thus give rise to bottom-up filling in even the lowest aspect-ratio cavities. Planar layers obtained by the ECMD technique have been successfully employed in an electrochemical polishing technique for stress-free removal of Cu.