Parametric Electrochemical Deposition of Controllable Morphology of Copper Micro-Columns

Abstract

This work demonstrates the fabrication of controllable morphology of micrometer copper columns using the localized electrochemical deposition (LECD) process, which is critical for MEMS and semiconductor related applications. Different morphologies of deposited copper micro-columns can be obtained by controlling the applied potential and initial distance between electrodes of LECD. Additionally, four kinds of morphological models, i.e., cylinder structure, conical structure, dendritic structure and vine structure were proposed to define the varied morphologies of deposits. Furthermore, base angle and branch number were introduced as the two critical characteristics to describe the proposed morphological models, and the dependences of the base angle and branch number on the applied potential as well as the initial distance between electrodes were systematically investigated. Finally, simulation of LECD process using COMSOL revealed that the electric field distribution affected by the potential and initial distance determined the morphology of micrometer copper columns, which well matched the experimental results.