PCB surface treatment
With the increasingly high integration of IC, IC more feet closer. Vertical HASL process blows hard to turn into a fine pad formation, which bring to SMT mounting difficulty; HASL with the life (shelf life) is very short. And gold-plated Board solves these problems:
For surface-mount technology, especially for very small SMD 0402 and 0603 because pad flatness is directly related to the quality of solder paste printing process, on the back of the reflow soldering quality plays a decisive influence, so the whole gold plate often seen in the high density and super-mini SMD technology.
At the trial stage and component purchases, the impact is often not to the Board as soon as welding, but often have to wait several weeks or even months, gold-plated Board using the life expectancy (shelf life) than tin-lead. Kanenaga many times so we are reluctant to adopt. gold-plated PCB-like phase cost almost the same compared with the pewter plate. But with the wiring increasingly dense, has arrived in 3-4MIL line width, spacing, so bring a wire short circuit problem; with the increasing frequency of signal, caused by skin effect signal transmission in a coating effect on the signal quality is more obvious. (Skin effect refers to: high frequency alternating current to flow will tend to focus on the surface of the wire).