Superconformal Bottom-Up Nickel Deposition in High Aspect Ratio Through Silicon Vias

Published

September 23, 2016

Author(s)

Daniel Josell, Thomas P. Moffat

Abstract

Abstract: This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled superconformal, void-free deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are fully detailed. The impact of deposition potential and additive concentration on the filling of the patterned features is presented. Voltammetric measurements on planar substrates, including the impact of rotation rate and suppressor concentration on the rate of metal deposition and potential of suppression breakdown, are used to quantify the interplay between metal deposition and suppressor adsorption. The derived kinetics are then used to quantitatively predict the observed bottom-up filling in the TSVs using the S-shaped negative differential resistance (S-NDR) mechanism for superconformal deposition; the predictions capture the experimental observations. This work extends understanding and application of the additive-derived S-NDR mechanism developed with non-ferrous metals.

Citation

ECS Transactions

Pub Type

Journals

Keywords

Nickel, TSV, through silicon via, filling, superconformal, superfill

Citation

Josell, D. and Moffat, T. (2016), Superconformal Bottom-Up Nickel Deposition in High Aspect Ratio Through Silicon Vias, ECS Transactions (Accessed April 18, 2024)