Applicable occasions: It is estimated that about 25%-30% of PCBs currently use the OSP process, and the proportion has been rising (it is likely that the OSP process has now surpassed the spray tin and ranks first). The OSP process can be used on low-tech PCBs or high-tech PCBs, such as single-sided TV PCBs and high-density chip packaging boards. For BGA, there are also many OSP applications. If the PCB has no surface connection functional requirements or storage period restrictions, the OSP process will be the most ideal surface treatment process.

The biggest advantage: It has all the advantages of bare copper board welding, and the board that has expired (three months) can also be resurfaced, but usually only once.

Disadvantages: susceptible to acid and humidity. When used for secondary reflow soldering, it needs to be completed within a certain period of time. Usually, the effect of the second reflow soldering will be poor. If the storage time exceeds three months, it must be resurfaced. Use within 24 hours after opening the package. OSP is an insulating layer, so the test point must be printed with solder paste to remove the original OSP layer to contact the pin point for electrical testing.

Method: On the clean bare copper surface, a layer of organic film is grown by chemical method. This film has anti-oxidation, thermal shock, moisture resistance, and is used to protect the copper surface from rusting (oxidation or vulcanization, etc.) in the normal environment; at the same time, it must be easily assisted in the subsequent high temperature of welding. Flux is quickly removed for soldering;