Electrochemical palladium deposition for reducing critical dimensions in nanostructures

Abstract

Electrochemical deposition of metals in devices with nanoscale dimensions can play an integral role in reducing critical dimensions of such devices and address challenges faced in microfabrication for miniaturization. This study focuses on electrochemical deposition of palladium on substrates such as titanium nitride, ruthenium and palladium that are commonly used in manufacturing of nanoscale devices such as nanochannels and nanopores. Cyclic voltammetry and hydrodynamic linear sweep voltammetry were used to understand the effects of electrolyte composition and operating conditions on palladium electrodeposition. Blanket (non-patterned wafer) samples of titanium nitride, ruthenium and palladium were plated to study the nucleation of palladium on these substrates and to understand nucleation trends at different operating conditions and electrolyte compositions. To study palladium plating in small openings, two test vehicles were designed. The first test vehicle had metal lines buried under oxide layers with 26 nm openings. The second test vehicle had interconnect-like metal lines with 90 nm spacing between the lines. Transfer of knowledge from beaker-scale experiments on blanket samples and electroanalytical techniques to plating in these test vehicles will be presented. For the first test vehicle the critical dimensions were reduced from 26 nm to 12 nm and for the second vehicle from 90 nm to 51 nm.