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Electrochemical and analytical study of electroplating additive in copper plating solution for microvia filling

Zhihua Tao (Center for Applied Chemistry, University of Electronic Science and Technology of China, Chengdu, China)
Guanting Liu (Center for Applied Chemistry, University of Electronic Science and Technology of China, Chengdu, China)
Yuanxun Li (State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, China and Dongguan Chengqi Cichuang innovation Materials Co Ltd, Guangdong, China)
Hua Su (State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, China)

Circuit World

ISSN: 0305-6120

Article publication date: 5 August 2019

Abstract

Purpose

The adsorption and acceleration behavior of 3-mercaptopropyl sulfonate (MPS) were investigated by electrochemical tests for microvia filling by copper electroplating.

Design/methodology/approach

The synergistic effects of one suppressor of propylene oxide ethylene oxide propylene oxide named PEP and MPS as the accelerator during copper electroplating were also investigated by electrochemical methods such as electrochemical impedance spectroscopy cyclic voltammetric stripping (CVS) and Galvanostatic measurements (GMs).

Findings

The research results suggest that the adsorption of MPS onto the Cu-RDE metal surface was a spontaneous process and the adsorbing of MPS on cathode was proposed to physical-chemistry adsorption in the plating formula. There was no potential difference (i.e. ?? = 0) of GMs until MPS was injected into the plating solution suggest that copper deposition is not diffusion-controlled in the presence of PEP–Cl–JGB.

Originality/value

A new composition of plating bath was found to be effective to perform bottom-up copper filling of microvias in the fabrication of PCB in electronic industries. The adsorption of MPS into the Cu-RDE metal surface was a spontaneous process and the adsorbing of MPS on cathode was studied by EIS and the results proposed to physical-chemistry adsorption in the plating formula. An optimal plating solution composed of CuSO4, H2SO4, chloride ions, PEP, MPS and JGB was obtained, and the microvia could be fully filled using the plating formula.

Keywords

Acknowledgements

The authors gratefully acknowledge the support of National Natural Science Foundation of China (No.61841401) and Sichuan Science and Technology Program (2019YFG0101, 2019YFG0280).

Citation

Tao, Z., Liu, G., Li, Y. and Su, H. (2019), "Electrochemical and analytical study of electroplating additive in copper plating solution for microvia filling", Circuit World, Vol. 45 No. 3, pp. 124-131. https://doi.org/10.1108/CW-07-2018-0052

Publisher

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Emerald Publishing Limited

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