Graphene-Oxide-Assisted Electroless Cu Plating on a Glass Substrate

Abstract

In recent years, the advancement of high-frequency communication systems, particularly 5G and future 6G technologies, has increased the need for substrates that minimize signal loss and electromagnetic interference. Glass substrates are highly desirable for these applications due to their low dielectric constant and excellent surface smoothness. However, conventional electroless Cu plating methods struggle to achieve strong adhesion between Cu and the smooth, low-polarity surface of glass, making this an important challenge to address. To overcome this issue, this study presents a novel electroless Cu plating method that employs graphene oxide (GO) as an intermediary layer on amino-functionalized glass substrates. During a preheating process at 150 °C, the GO layer forms covalent C–N bonds with the amino-modified glass, significantly enhancing adhesion while preserving the surface smoothness required for high-frequency applications (R_a = 6.6 nm). This GO-based approach eliminates the need for traditional surface roughening techniques. Additionally, by incorporating silver nanoparticles (Ag NPs) as a catalyst, this method provides a cost-effective alternative to conventional palladium-based processes for Cu electroless plating. The resulting Cu film exhibits excellent adhesion, as confirmed by tape peel tests and a low volume resistivity of 2.4 μΩ·cm, making it well-suited for applications that require minimal signal loss at high frequencies.This innovative technique not only enhances the adhesion of the conductive layer but also maintains the surface smoothness crucial for high-frequency signal transmission, positioning it as a promising solution for the fabrication of advanced substrates in next-generation communication technologies.