1. FPC flexible circuit board immersion gold
Advantages: It is not easy to oxidize, can be stored for a long time, and the surface is flat. It is suitable for soldering fine gap pins and components with small solder joints. It can be repeated repeatedly for reflow soldering and it will not reduce its solderability.
Disadvantages: high cost, poor soldering strength, because of the use of electroless nickel process, easy to have black disk problems. The nickel layer oxidizes over time and long-term reliability is a problem.
2. FPC flexible circuit board sinks silver
Advantages: Simple process, suitable for lead-free soldering, SMT. The surface is very flat, low cost and suitable for very fine lines.
Disadvantages: High storage requirements and easy contamination. The welding strength is prone to problems (micro-cavity problems). It is prone to electromigration and the occurrence of Giovanni bite in the copper under the solder mask. Electrical measurement is also a problem.
3. FPC flexible circuit board nickel-plated gold
Advantages: Long storage time >12 months. Suitable for contact switch design and gold wire bonding. Suitable for electrical testing
Disadvantages: Higher cost, gold is thicker. Additional design lines are required to conduct electricity when plating gold fingers. Because the thickness of gold is not always applied, when it is applied to the welding, the solder joint may be embrittled due to too thick gold, which may affect the strength. Plating surface uniformity issues. The plated nickel gold does not wrap the edges of the wire.
4. FPC flexible circuit board tin plating
Advantages: Suitable for horizontal production. Suitable for fine line processing, suitable for lead-free soldering, especially suitable for crimping technology. Very good flatness, suitable for SMT.
Disadvantages: Good storage conditions are required, preferably no more than 6 months to control tin whisker growth. Not suitable for contact switch design. The process requirements for the solder mask process are relatively high, otherwise the solder mask will fall off. When welding multiple times, it is best to protect with N2 gas. Electrical measurement is also a problem.
5. FPC Flexible Circuit Board Organic Solderability Protector (OSP)
Advantages: Simple process, very flat surface, suitable for lead-free soldering and SMT. Easy to rework, easy to produce and operate, suitable for horizontal operation. Low cost and environmentally friendly.
Disadvantages: Restriction of reflow times, not suitable for crimping technology, wire bonding. Visual inspection and electrical measurement are inconvenient. N2 gas protection is required for SMT. SMT rework is not suitable. Storage conditions are high.