Electroless Atomic Layer Deposition of Pt on Cu Nanowires

Abstract

Pt is a material widely used as a catalyst in many areas of chemical synthesis and energy conversion and as a protective layer and etch stop barrier in the semiconductor industry. Due to high surface free energy, Pt exhibits a rough 3D growth (Volmer – Weber) mode. This represents a challenge when ultrathin and conformal layers of Pt are needed. The electroless ALD process presented here enables uniform and selective deposition of Pt on micro patterned Cu structures/wires on Si and SiO2, offering an opportunity for simplified integration into more complex fabrication routes currently used in semiconductor fabs. Outline of the process: Pt is deposited on Cu lines by surface limited redox replacement (SLRR). Monolayer of Pb is deposited on Cu/Pt using an ‘electro-less’ approach utilizing V2/3+ redox couple. Pb monolayer on Cu/Pt serves as a reducing agent for Pt deposition (self-limited to 1 ML).