Superconformal and Bottom-up Filling of High Aspect Ratio Features

Abstract

Superconformal, and more particularly bottom-up, copper electrodeposition in fully metallized, high aspect ratio features enables the fabrication of interconnects, including in chip stacking technologies. I will discuss mechanistic understanding of such bottom-up filling processes for cobalt, nickel, gold and copper deposition in through silicon vias from electrolytes containing (only) deposition rate suppressing additives as well as analogous bottom-up gold filling of similar size trenches from electrolyte containing deposition accelerating bismuth additive. Electrochemical measurements on planar substrates combined with mechanistic understanding enable accurate a-priori prediction of filling evolution and, for the nickel, cobalt and gold suppressor-based systems, microstructural variation associated with additive incorporation.