Analysis of Electrical Resistance Behavior and Oxide Film Growth Mechanism by Low-Temperature Oxidation of Copper Wiring in Printed Circuit Boards

Abstract

We found two slope change points (0.25 and 8 h) in the electric resistance of Cu wiring between 0 and 100 h by performing an oxidation process at 150°C on printed circuit boards (PCB). We formed a Pt film on Cu by sputtering and used STEM (Scanning Transmission Electron Microscopy) and AES(Auger electron spectroscopy) to investigate the formation process of the oxide film growing as the boundary of the Pt film. Our results show that the growth rate of the oxide film between the two slope change points (0–0.25 h, 0.25–8 h) was linearly regressed against the oxidation time, indicating that the change in the growth rate of the oxide film was affected by the passage of time. We found that the main oxide film structure formed between 0 and 8 h was Cu₂O, and after 100 h, a thin layer of CuO started to form on top of the layer of Cu₂O.