Superconformal Electrodeposition of Co and Co-Fe Alloys using 2-Mercapto-5-benzimidazolesulfonic Acid (MBIS)

Published

June 10, 2009

Author(s)

Chang H. Lee, John E. Bonevich, Joseph E. Davies, Thomas P. Moffat

Abstract

Superconformal Co(Fe) filling of submicrometer trenches by electrodeposition is demonstrated in the presence of 2-mercapto-5-benzimidazolesulfonic acid (MBIS). MBIS inhibits the initiation of Co deposition. Inhibition breakdown is characterized by hysteretic voltammetry and rising chronoamperometric transients. The positive feedback process reflects the competition between MBIS adsorption and its desorption, and/or consumption, with the latter being closely coupled with proton reduction and/or the metal deposition reaction. Void-free Co trench filling proceeds by preferential metal deposition at the bottom corners leading to a v-notch interface shape that is followed by geometrical leveling. Void-free filling is also demonstrated for a via geometry. Almost identical superconformal trench filling is obtained for Co-rich Co-Fe alloys. Analytical TEM-EDX indicates that the Fe/Co ratio within the filled trenches is uniform. MBIS does not significantly perturb the magnetic properties of the Co or Co-Fe alloy deposits.

Citation

Journal of the Electrochemical Society

Volume

156

Issue

8

Pub Type

Journals

Citation

Lee, C. , Bonevich, J. , , J. and Moffat, T. (2009), Superconformal Electrodeposition of Co and Co-Fe Alloys using 2-Mercapto-5-benzimidazolesulfonic Acid (MBIS), Journal of the Electrochemical Society (Accessed October 11, 2025)