The surface finish is necessary to complete a circuit board. PCB surface treatments come in a variety of varieties. The difficulties of varied operational conditions must be endured by PCBs. Consequently, surface finishes must be applied to the printed circuit. One often utilized surface treatments is ENIG plating. More information on this sort of surface treatment is provided in the article.
What Does ENIG Plating PCB Mean?
An ENIG surface finish has gold on top of the nickel layer. ENIG plating offers some oxidation and corrosion resistance. Additionally, the industry uses this surface finish extensively. This is due to the product’s RoHS compliance. Two layers of coating are used in ENIG plating Circuit board. The materials utilized in this kind of plating are gold and nickel.
The nickel acts as a specific barrier between the copper pads and the air. Additionally, it is a substance whereby the maker solders the parts. Gold, meanwhile, provides low level of contact resistance and protects the nickel. The term “immersion gold” also applies to ENIG plating. One advantage of the immersion gold involves its ability to electrolessly bond both nickel and gold to copper.
ENIG plating is covered with a gold layer during gold plating. In addition, this immersion gold layers acts as an oxidation-resistant barrier. Preventing chemical reactions is one of the many advantages of ENIG plating.
Therefore, PCB designers generally like this surface treatment. In ENIG plating, conventional electroless nickel and the gold layer are combined. Additionally, this coating can stick to metal substrates like aluminum. This surface finish is perfect because of the nickel coating. Nickel is also appropriate for the process of lead-free soldering.
ENIG plating circuit board uses a brief immersion to apply gold. Additionally, enig uses the displacement principle. Additionally, this plating applies a thin gold layer by dispersing its surface atoms. Parts that require soldering can have their shelf life extended with ENIG coating. Additionally, it provides outstanding electrical performance.
Process of the ENIG plating Circuit Board
Surface Preparation
Before plating, this PCB surface needs to be exceptionally clean. Additionally, there must be no dirt on this surface. Surface preparation is the first step in the gold plating process. This same PCB surface may also be stripped or polished in this process. This procedure uses water as well as any abrasive materials.
In this procedure, the copper plate’s roughness is eliminated. This process aids in strengthening its copper surfaces as well as electroplated layers. Additionally, it raises PCB quality.
Activation of the immersion gold
Use of copper plating parameters is required for this phase. The thickness of the nickel layer can be adjusted. The nickel-plated pads are dipped by the manufacturer in the gold water. This gold can then be removed from the solution. The final step is to clean the surface of the pad to ensure that there is no dirt on it.
Benefits of the ENIG Plating Circuit Board
Employing ENIG plating has a number of benefits, such as:
Good resistance to oxidation
Manufacturers of PCBs with experience favor surface finishes which can withstand oxidation. PCBs with immersion gold plating provide excellent oxidation resistance. Additionally, this sort of circuit board surface treatment includes immersion gold above the electroless nickel plating. The gold coating inhibits oxidation of the nickel. Consequently, ENIG plating guarantees a printed circuit’s resistance to corrosion.
Withstand high temperatures
An important benefit of the ENIG plating is this. The majority of circuit boards utilized in military and medical equipment operate at high temperatures. In these situations, ENIG plating can be described as the best solution for PCB surface finishing. Additionally, ENIG is suggested since it can endure high temperatures. Excellent thermal diffusion capabilities can be found in an ENIG coating. In addition, this ENIG plating can resist very high temperatures.
It is lead free
Both humans as well as their environment can be poisoned by lead. Health problems may result from lead exposure at high amounts. ENIG plating is lead-free. Additionally, this implies that harmful compounds really aren’t exposed to PCB makers. As a result, ENIG plating is frequently utilized in electronics.
For use on untreated surfaces
It is crucial to protect these untreated surfaces from oxidation. Based on the surface finish type utilized, this exercise may be difficult. For untreated surfaces such as membrane switches as well as contact points, ENIG plating is appropriate. Additionally, immersion gold provides superb surface planarity. This makes it appropriate in comparison to other surface treatments.
RoHS conformity
The RoHS directive forbids the use of around ten of the most harmful materials in the manufacture of electronic equipment. ENIG plating usually meet all the ROHS requirements. Here is one good reason why circuit board designers usually love this type of surface finish.
What are the Cons of ENIG Plating?
Black pad
Black pad is an undesirable structure that appears during ENIG plating. Additionally, this is caused by a sulfur-based chemical leaking from this solder mask. Electrical isolation may result from black pad development. Black pads are unable to transmit the electrical charge, which explains why. Black pads may also result in surface cracks on your PCB. As a result, good solderability and evenness may be compromised.
Poorly soldered joints
Weak solder junctions may result from inadequate wetting. Additionally, the circuit board may have a kind of weak connection as a result of this. Electrical continuity loss may be the result of inadequate wetting.
Really pricey
ENIG plating is very expensive. Compared to other PCB surface coatings, this is much more expensive. Additionally, it costs more than OSP and HASL. Gold and other expensive materials are used in ENIG plating. This type of surface finish cannot be reworked, either. As a result, ENIG plating is quite expensive.
Loss of signal
When used for a long time, ENIG plating may undergo signal degradation. As a result, this may have an impact on your PCB’s general performance.
Conclusion
The circuit boards are essential to how electronic gadgets operate. For the PCB plating, a variety of surface treatments are offered. An excellent option for PCB assembly is ENIG plating. Additionally, this kind of surface treatment is perfect for usage in areas where corrosion resistance is necessary.
