Immersion gold is a process that applies a very thin layer of gold with displacement of the surface atoms. It means the coating is not very thick, and it can be used for extending the shelf life of parts waiting for soldering operations because of corrosion resistance.

Immersion gold has been applied in aluminum and gold wire bonding and PCB fabrication. But it can’t be used to take place electrolytic gold plating because its thickness and adhesion are limited compared to a standard electroplated gold. If you are going to learn more about immersion gold, please check and read the content below for more professional knowledge.

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What are the advantages and disadvantages of immersion gold?

When it comes to immersion gold and gold plating, a lot of PCB manufacturers is fabricated your circuit boards with immersion gold, because there is a poor solderability in plating gold.

Advantages:

·  Flat Surface

·  No Pb

·  Simple Process

·  Re-workable

·  Cost Effective

Disadvantages:

·  No Way to Measure Thickness

·  Not Good for PTH (Plated Through Holes)

·  Short Shelf Life

·  Can Cause ICT Issues

·  Exposed Cu on Final Assembly

·  Handling Sensitive

What are the features of immersion gold in PCB?

This type of finish involves a two-layer metallic coating; it consists of electroless plating that is covered with a thin layer of immersion gold, the function of the immersion gold is to safeguard the nickel from oxidizing during storage, and the nickel functions more like a barrier to the copper and a surface on which the components are soldered. Recently, due to the advantages provided by ENIG, ENIG is one of a printed circuit board (PCB) industry, the most common types of surface treatment, including a plane, lead-free, suitable for plated through holes (PTH), long shelf life.

In the early stages of ENIG plating, reliability is still unclear, i.e., this type of leaf had dependability problems. This has resulted in the disuniting of the copper pads from the finish. Unlike the hot air solder leveling, the electroless immersion nickel-gold does not uniformly wet. To ensure that the conventional coating provides the proper temperature and concentration, the reducing agent consisting of nickel ions must be renewed.

What are the main aspects of immersion gold in PCB?

Easy to soldering

Based on different crystal structure those get formed by both Gold plating and ENIG. Additionally, welding ENIG does not bring about welding defects based on the fact that ENIG is a bit softer than Gold plating. It is easy to control the stress in immersion gold as opposed to Gold plating.

Widely applications

Unlike other types of solutions that may fail to function as desired across several electronic products, something good about ENIG PCB is that it can perfectly fit across various electronic products with much ease.

Last but not least, another notable advantage associated with ENIG (Electroless Nickel Immersion Gold) surface coating is that it finds much use in a variety of electronic products from computer motherboards to wearables, and medical appliances, among others.

Non-require electroplating

ENIG is best known for being corrosion-resistant, and a common type of plating commonly used when it comes to the manufacture of printed circuit boards. As mentioned earlier, ENIG consists of a gold layer on top of a nickel layer.

Lead-free

Another significant advantage associated with immersion gold or ENIG is that it is lead-free, meaning that manufacturers are not exposed to harmful chemicals when using it as a surface finish on PCBs. Since regular exposure to high lead levels may bring about several complications such as brain and kidney damage and body weakness.

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