What is ENIG? If it’s so expensive, why use it?

June 8, 2026

1. What is ENIG?

Simply put, ENIG (Electroless Nickel Immersion Gold) is a chemical deposition method. It uses a chemical oxidation-reduction reaction to produce a metallic gold coating on the surface of a printed circuit board (PCB).

2. Why use ENIG?

The copper on a circuit board is mainly bare copper. Copper solder pads are easily oxidized in the air, which can lead to poor conductivity — meaning poor soldering or bad contact — and reduces the performance of the circuit board.

Therefore, the copper pads need surface treatment. ENIG is a process that deposits gold on them. Gold effectively prevents the copper metal from contacting air and oxidizing, making ENIG a method for anti-oxidation protection. It chemically covers the copper surface with a layer of gold, which is why it is also called Immersion Gold.

3. What are the advantages of ENIG surface treatment?

The benefits of the ENIG process include a very stable deposited color on the printed traces, excellent brightness, a flat and even plating layer, and very good solderability.

Typically, the gold thickness for ENIG is 1–3 micro-inches. Because the resulting gold layer is relatively thick, ENIG is widely used on keypads, gold finger boards, and other PCBs where gold’s strong conductivity, good oxidation resistance, and long service life are valued.

4. What are the benefits of using ENIG boards?

The main advantages are as follows:

1. ENIG boards have a bright, attractive color and good appearance.

2. The crystalline structure formed by ENIG makes it easier to solder than other surface finishes, ensuring good performance and quality.

3. Since ENIG deposits nickel and gold only on the pads, it does not affect the signal. Due to the skin effect, signal transmission occurs in the copper layer.

4. Gold has a stable metallic property and a denser crystal structure, making it resistant to oxidation.

5. Because only the pads have nickel and gold, the solder mask on the traces bonds more firmly with the copper layer, reducing the risk of micro-shorts.

6. Engineering compensation does not affect spacing.

7. The stress of ENIG boards is easier to control.

5. ENIG vs. Gold Fingers

To put it bluntly, gold fingers are brass contacts — or simply conductors.

More specifically, gold has excellent oxidation resistance and strong conductivity. That’s why gold is plated on the parts of a memory module that connect to the memory slot — all signals are transmitted through the gold fingers.

Gold fingers get their name because they are made up of many yellow conductive contact pads, are gold-plated on the surface, and the arrangement of the contacts looks like fingers.

In simple terms, gold fingers are the connecting parts between a memory module and its slot. All signals are transmitted through them. Gold fingers consist of many golden conductive contacts. In reality, a gold finger is a copper-clad board with an additional layer of gold applied through a special process.

So, a simple distinction: ENIG is a surface finish process for PCBs, while gold fingers are the components on a PCB used for signal connection and conduction.

In the real market, gold fingers are not necessarily truly gold on the surface.

Due to the high cost of gold, many memory modules now use tin plating instead. Since the 1990s, tin materials have become widespread. Today, the "gold fingers" on motherboards, memory modules, and graphics cards are mostly made of tin. Only high-performance server/workstation components continue to use gold plating — and their prices are naturally much higher.

Now that you understand the benefits of ENIG, selecting a trusted PCB manufacturer is just as important. Bicheng PCB not only masters ENIG and other surface finishes, but has also built deep expertise in Immersion Silver, Immersion Tin, HASL, and more. Backed by strong manufacturing capabilities, a wide range of material options, and superior process technology, we offer one-stop custom PCB services. No matter your project needs, we welcome you to reach out to us.