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Study on fine lines and undercut suppression of printed circuit board prepared by electrolytic etching

Denglin Fu (School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China)
Yanan Wen (Chongqing University, Chongqing, China)
Jida Chen (Chongqing University, Chongqing, China)
Lansi Lu (Chongqing University, Chongqing, China)
Ting Yan (Chongqing University, Chongqing, China)
Chaohui Liao (Chongqing University, Chongqing, China)
Wei He (School of Materials and Energy and Center for Applied Chemistry, University of Electronic Science and Technology, Chengdu, China)
Shijin Chen (Bomin Electronics Ltd., Meizhou, China)
Lizhao Sheng (Jiangsu Bomin Electronics Ltd., Yancheng, China)

Circuit World

ISSN: 0305-6120

Article publication date: 3 August 2021

Issue publication date: 6 February 2023




The purpose of this paper is to study an electrolytic etching method to prepare fine lines on printed circuit board (PCB). And the influence of organics on the side corrosion protection of PCB fine lines during electrolytic etching is studied in detail.


In this paper, the etching factor of PCB fine lines produced by new method and the traditional method was analyzed by the metallographic microscope. In addition, field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the inhibition of undercut of the four organometallic corrosion inhibitors with 2,5-dimercapto-1,3,4-thiadiazole, benzotriazole, l-phenylalanine and l-tryptophan in the electrolytic etching process.


The SEM results show that corrosion inhibitors can greatly inhibit undercut of PCB fine lines during electrolytic etching process. XPS results indicate that N and S atoms on corrosion inhibitors can form covalent bonds with copper during electrolytic etching process, which can be adsorbed on sidewall of PCB fine lines to form a dense protective film, thereby inhibiting undercut of PCB fine lines. Quantum chemical calculations show that four corrosion inhibitor molecules tend to be parallel to copper surface and adsorb on copper surface in an optimal form. COMSOL Multiphysics simulation revealed that there is a significant difference in the amount of corrosion inhibitor adsorbed on sidewall of the fine line and the etching area.


As a clean production technology, electrolytic etching method has a good development indicator for the production of high-quality fine lines in PCB industry in the future. And it is of great significance in saving resources and reducing environmental pollution.



This research was supported by the projects of “Sail Plan for Talents Development” of Guangdong Province China (No. 2015YT02D025).


Fu, D., Wen, Y., Chen, J., Lu, L., Yan, T., Liao, C., He, W., Chen, S. and Sheng, L. (2023), "Study on fine lines and undercut suppression of printed circuit board prepared by electrolytic etching", Circuit World, Vol. 49 No. 1, pp. 1-12.



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