Principle: An organic film is formed on the copper surface of the circuit board, which firmly protects the surface of fresh copper, and can also prevent oxidation and pollution at high temperatures. OSP film thickness is generally controlled at 0.2-0.5 microns.

1. Process flow: degreasing → water washing → micro-erosion → water washing → acid washing → pure water washing → OSP → pure water washing → drying.

2. Types of OSP materials: Rosin, Active Resin and Azole. The OSP materials used by Shenzhen United Circuits are currently widely used azole OSPs.

What is the OSP surface treatment process of PCB board?

3. Features: good flatness, no IMC is formed between the OSP film and the copper of the circuit board pad, allowing direct soldering of solder and circuit board copper during soldering (good wettability), low temperature processing technology, low cost (low cost) For HASL), less energy is used during processing, etc. It can be used on both low-tech circuit boards and high-density chip packaging substrates. PCB Proofing Yoko board prompts the shortcomings: ① appearance inspection is difficult, not suitable for multiple reflow soldering (generally requires three times); ② OSP film surface is easy to scratch; ③ storage environment requirements are high; ④ storage time is short.

4. Storage method and time: 6 months in vacuum packaging (temperature 15-35℃, humidity RH≤60%).

5. SMT site requirements: ① The OSP circuit board must be kept at low temperature and low humidity (temperature 15-35°C, humidity RH ≤60%) and avoid exposure to the environment filled with acid gas, and assembly begins within 48 hours after unpacking the OSP package; ② It is recommended to use it within 48 hours after the single-sided piece is finished, and it is recommended to save it in a low-temperature cabinet instead of vacuum packaging;