Corrosion Behavior of Copper Foil on PCB Substrates Under Atmospheric Environment in Sichuan-Tibet Region of China

Copper foil is widely used in electronic components and devices. This study investigates the corrosion behavior of copper foil on printed circuit boards exposed for one year in a closed atmospheric environment across 22 different sites in the Sichuan-Tibet region. Through electrochemical, SEM/EDS, and XRD analyses, the corrosion behavior of copper foil material across the five selected sites (Meishan, Mangkang, Luding, Batang, and Panzhihua) and the influence of environmental factors were discussed. The results show that copper foils in areas with a large temperature change, higher humidity, and more rainfall exhibit more severe corrosion. The corrosion products primarily form a double-layer structure; the bottom layer consists of relatively stable Cu₂O, while the type of corrosion product in the upper layer is strongly influenced by the local climatic environment, predominantly containing CuSO₄, CuSO₄(OH), and Cu₂Cl(OH)₃. In dry areas, copper oxides tend to form, whereas in humid areas, copper sulfides are more likely to grow.