sales@ipcb.com
Nowadays, there are many PCB manufacturers, but not many PCB manufacturers can do a good job of OSP process, because the processing of OSP PCB need to have a rich experience in PCB manufacturing process. what are the advantages and disadvantages of the OSP process?
Pure copper is easily oxidised if it is exposed to the air, and there must be a protective layer on the outside of the circuit board. Therefore, it is necessary to carry out surface treatment in the circuit board process. OSP is a commonly used surface treatment process. OSP is different from other surface treatment processes in that it acts as a barrier layer between copper and air, and is ROHS compliant and environmentally friendly.
Simply, OSP is an organic film grown chemically on a clean, bare copper surface. Because it is organic and not metal, it is cheaper than HASL.
The purpose of the OSP organic film is to ensure that the inner layer of copper foil is not oxidised before soldering. Once heated during soldering, the film will evaporate and the solder will be able to bond the copper wires and components together. However, this layer of organic film is not corrosion-resistant, a piece of OSP circuit board, exposed to air for 1-2 days, can not be soldered components. Many computer mother boards use OSP technology.
Advantages of OSP process
1. Low cost of PCB process
2. High soldering strength of PCB
3. Good solderability of PCBs
4. Surface flatness of soldering pads
5. Expired PCB is easy to rework
In conclusion, OSP PCB process has all the advantages of bare copper soldering, and the expired PCB can be reworked for surface treatment.
Disadvantages of OSP process
1. The contact resistance of PAD is a little high, which affects the electrical measurement.
2. Easily oxidised, not suitable for wire bonding.
3. Poor thermal stability, generally after a high-temperature furnace will no longer have anti-oxidation protection.
4. Short process time, the first welding must be completed within 24 hours after the subsequent welding.
5. The circuit board is not corrosion-resistant.
6. High printing requirements, can not be printed wrong, because cleaning will damage the OSP film.
7. Poor tin permeability of wave soldering holes.
In general, OSP is transparent and colourless, so it is difficult to check whether it has been treated with OSP or not. OSP itself is insulated and does not conduct electricity, which will affect the electrical test. Therefore, the test point must be opened with a steel mesh and printed with solder paste to remove the original OSP layer before contacting the needle point for electrical testing. OSP cannot be used to handle electrical contact surfaces such as keypad surfaces. OSP is susceptible to acid and temperature. When used for secondary reflow, it needs to be completed within a certain period of time, and the result of the second reflow is usually poorer. If the storage time is more than three months, it must be re-surfaced. It should be used within 24 hours after opening the package.
Audemars Piguet is a professional OSP PCB manufacturer, with 20 years of experience in making circuit boards! Welcome for your technical consultation or price inquiry!