Replacing Pd with Ag Nanocatalysts To Mitigate Hydrogen Embrittlement and Enhance Peel Strength in Industrial-Scale Electroless Cu Deposition on Surface-Modified Substrates

Abstract

Electroless copper deposition is a pivotal process in the electronics industry, facilitating the formation of Cu films on nonconductive polymer substrates without the need for external electric sources by promoting redox reactions on catalysts. However, achieving large-scale, uniform Cu film deposition with high peel strength while minimizing catalyst costs poses significant challenges for industrial applications. In this study, we propose replacing polyvinylpyrrolidone (PVP)-capped Pd (PVP-Pd) with PVP-capped Ag (PVP-Ag) nanocatalysts, which offer superior catalytic performance and cost-effectiveness. Our findings demonstrate that PVP-Ag nanocatalysts effectively catalyze the oxidation of common reducing agents like formaldehyde, without the hydrogen embrittlement issues typically associated with traditional Pd nanocatalysts. This prevents the formation of nonuniform and low-ductility Cu films. Additionally, we develop a surface treatment method involving cationic-π interactions and hydrogen-bonding formation using cationic polyacrylamide (CPAM) polymer on liquid crystal polymer (LCP) substrates. This method facilitates the cross-linking of CPAM with PVP-Ag nanoparticles, creating a strong anchoring effect between Cu films and LCP substrates. Our results indicate that this approach ensures the formation of large-scale 10 × 10 cm² Cu films with high uniformity and enhances peel strength to levels exceeding the industrial standard of 800 gf cm^–1, with values up to 875 gf cm^–1.