TY - BOOK

T1 - Fundamental study of the copper etching process in the manufacturing of printed circuit boards

AU - Körbler, Nadine

N1 - embargoed until 03-03-2028

PY - 2023

Y1 - 2023

N2 - Printed circuit boards (PCBs) are an essential component of electronic devices, providing the foundation for electrical connections. The manufacturing involves a series of different steps, to obtain highest quality products with excellent electrical properties revealing the etching process as the most crucial step by a precise dissolving of the unprotected copper from the surface yielding the desired circuitry. Therefore, the corrosion behavior of copper in cupric chloride solutions applied in the etching process for the production of printed circuit boards was investigated. For this purpose, defined aging tests of pure copper cubes in industrially relevant solutions under stagnant and convective conditions provided information on the influences of the parameters temperature, concentration and bath movement to the etching rate. An electrochemical study performed in a three-electrode arrangement offered data for the identification of anodic and cathodic surface phenomena by recording representative current-potential diagrams. Polarization of various electrode materials according to dedicated methods of linear and cyclic voltammetry revealed the influence of reactive species on the dissolution behavior related to limitations of mass and charge transfer by extracting characteristic currents as a function of the potential. The investigations confirm the positive effect to the dissolution at elevated temperature and HCl contents in combination with a forced bath movement. Detailed examinations showed that the formation of CuCl at the surface cannot be influenced by either concentration of reactive species or convection. Screening the reaction limitations, exhibits mass transfer-controlled dissolution properties for systems of high HCl levels. The acquired capabilities enable positive impacts as well as economical operations to the etching process in the manufacturing of printed circuit boards.

AB - Printed circuit boards (PCBs) are an essential component of electronic devices, providing the foundation for electrical connections. The manufacturing involves a series of different steps, to obtain highest quality products with excellent electrical properties revealing the etching process as the most crucial step by a precise dissolving of the unprotected copper from the surface yielding the desired circuitry. Therefore, the corrosion behavior of copper in cupric chloride solutions applied in the etching process for the production of printed circuit boards was investigated. For this purpose, defined aging tests of pure copper cubes in industrially relevant solutions under stagnant and convective conditions provided information on the influences of the parameters temperature, concentration and bath movement to the etching rate. An electrochemical study performed in a three-electrode arrangement offered data for the identification of anodic and cathodic surface phenomena by recording representative current-potential diagrams. Polarization of various electrode materials according to dedicated methods of linear and cyclic voltammetry revealed the influence of reactive species on the dissolution behavior related to limitations of mass and charge transfer by extracting characteristic currents as a function of the potential. The investigations confirm the positive effect to the dissolution at elevated temperature and HCl contents in combination with a forced bath movement. Detailed examinations showed that the formation of CuCl at the surface cannot be influenced by either concentration of reactive species or convection. Screening the reaction limitations, exhibits mass transfer-controlled dissolution properties for systems of high HCl levels. The acquired capabilities enable positive impacts as well as economical operations to the etching process in the manufacturing of printed circuit boards.

KW - Leiterplatten

KW - Kupferätzen

KW - kupferchloridhaltige Lösungen

KW - Auslagerung

KW - Voltammetrie

KW - Printed circuit boards

KW - copper etching

KW - cupric chloride solution

KW - voltammetry

KW - exposure

M3 - Doctoral Thesis

ER -