Principle and introduction of OSP surface treatment process for PCB

the circuit board, which firmly protects the surface of fresh copper and can 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-etching → water washing → pickling → pure water washing → OSP → pure water washing → drying.

2. OSP material types: Rosin, ActiveResin and Azole. The OSP materials used by Shenzhen United Circuits are currently the most widely used azole OSPs.

What is the OSP surface treatment process of PCB board

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

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 stored at low temperature and humidity (temperature 15-35 ° C, humidity RH ≤ 60%) and avoid exposure to acidic environment. Assembly of the OSP package should be started within 48 hours after unpacking; ② It is recommended to use it within 48 hours after the single-sided piece, and it is recommended to store it in a low temperature cabinet instead of vacuum packaging; ③ It is recommended to complete the DIP within 24 hours after the SMT is completed on both sides.