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ENIG (electroless nickel immersion gold) and ENEPIG (electroless nickel immersion gold over palladium immersion gold) are two common PCB surface treatment technologies, which have significant differences in structure, performance, application and cost. The following are the main differences between the two:
1. Structural differences
ENIG:
Double-layer structure: nickel layer (3~6µm) + gold layer (0.05~0.12µm).
Process flow: First, a layer of nickel is chemically plated on the copper pad, and then a thin layer of gold is formed through a displacement reaction.
ENEPIG:
Three-layer structure: nickel layer + palladium layer + gold layerProcess flow: A layer of chemically plated palladium is added on the basis of ENIG, and the palladium layer is located between the nickel layer and the gold layer.
2. Performance Differences
ENIG:
Advantages:
1.High surface flatness, suitable for fine pitch components (such as BGA).
2.Low contact resistance and good corrosion resistance.
3.Low cost and mature process.
Disadvantages:
1.There is a "black nickel" problem (the nickel layer is excessively corroded, resulting in poor welding).
2.Wetting is slightly poor.
3.Not suitable for some high reliability scenarios.
ENEPIG:
Advantages:
1.The "black nickel" problem is solved, and the palladium layer effectively protects the nickel layer from being corroded by the gold layer.
1.Higher welding reliability and wire bonding capability.
2.Higher high temperature resistance and corrosion resistance.
3.Suitable for high frequency, high density and high performance PCB design.
Disadvantages:
1.Higher cost due to the addition of the palladium layer.
2.High process complexity.
3. Application scenarios
ENIG:
1.Applicable to general consumer electronics.
2.Cost-sensitive applications.
3.Scenarios that require good surface flatness but do not require particularly high reliability.
ENEPIG:
1.Applicable to fields with high reliability requirements, such as aerospace, medical equipment, automotive electronics, etc.
2.Occasions involving high-frequency signal transmission or fine wire bonding pcb.
3.Environments that require long-term stability and corrosion resistance.
4. Cost comparison
ENIG has a lower cost because its process is simple and the amount of material used is small.
ENEPIG has a higher cost, mainly due to the addition of a palladium layer and a more complex process flow.
5. Flatness and welding performance
ENIG surface is very flat, which may cause poor welding problems in some cases.
ENEPIG surface is also flat, providing higher welding reliability and consistency.
Conclusion:
If your PCB application requires higher reliability and welding performance and has sufficient budget, you can choose ENEPIG; if you are cost-sensitive and reliability requirements are not high, ENIG is a more economical choice. If you have any doubts for these 2 surface treatment,you can email Xinfeng Huihe Electronic Technology Co.,Ltd Via email: Sales@hhetech.com