ENIG Printed Circuit Board Manufacturing

ENEPIG PCBs were popular many years ago due to their overall board support and are now rising up once again thanks to a significant decrease in the cost of palladium. The design has been shown to successfully operate in conjunction with lead-free and eutectic solder alloys as well as most assembly processes.

ENIG PCB Manufacturing
ENIG PCB Manufacturing

The best features of ENIGs its flat surface and excellent solderability. The Electroless Nickel is an auto-catalytic process that deposits Nickel on a Palladium catalyzed Copper surface. Immersion Gold is replacement chemistry. In other words, it attaches to the Nickel by replacing atoms of Nickel with atoms of Gold. The recommended Gold thickness is 2-4 µin. The purpose of the immersion Gold layer is to protect the Nickel surface and maintain its solderability.

ENEPIG Circuit Boards Technology and Manufacturing Process

Different from ENIG, ENEPIG takes four layers of metal structure including copper, nickel, palladium and gold. The process of ENEPIG is the same as that of ENIG except that electroless palladium plating is added between ENP and immersion gold.

Palladium layer is added to ENEPIG technology as a barrier layer, stopping corrosion of the nickel layer caused by solution in the process of gold deposition and diffusion from nickel layer to gold layer. Meanwhile, palladium layer can be treated as anti-oxidation layer and anti-corrosion layer because of its feature of compact to increase the solderability. Similar to electroless nickel plating, electroless palladium plating leads to the deposition of palladium layer through redox reaction with NaH2PO2 as reducing agent. The reaction formula indicating this step is shown as the follows:

H2PO2 + H2O → H+ + HPO32- + 2H

Pd2+ + 2H → Pd↓ + 2H+

H2PO2 + H → P↓ + OH + H2O

H2PO2 + H2O → H2↑ + H+ + HPO32-

These are the PCB surface finishes we have available for your PCB order.
For more ENIG PCB Manufacturing information, please contact our experts at nicholas@mokotechnology.com or get a PCB production quote.

Gold Finish May be Electrolytic Electroless, or Immersion
– ENIG
(Electroless Nickel Immersion Gold)
2-5 micro inches. Purpose: To prevent oxidation, extend shelf life, provide a wire bonding surface (when aluminum wire is used), and used to provide an electrically conductive surface on PCBs. Used for solderability when the flatness of the pad is critical. ENIG has shelf life longer then 12 months.
– Hard Gold Purpose: Used for Gold Fingers (minimum 30 micro inches), soldering (maximum 17 micro inches), to prevent oxidation and extend shelf life.
– Soft Gold Purpose: Used for wire bonding (Ultrasonic minimum 2 micro inches/Thermasonic minimum 30 micro inches) and to prevent oxidation and extend shelf life.
Immersion Silver Use for solderability purposes (2-10 micro inches). Used for solderability when the flatness of the pad is critical.
Lead Free Solder Use for solderability purposes (2-5 micro inches). Used for solderability when the flatness of the pad is not critical.
OSP
Organic Solderability Preservatives)
Used for solderability when the flatness of the pad is critical.
White Tin (Immersion Tin) Used for solderability when the flatness of the pad is critical.

Our ENIG PCB Manufacturing Samples

8 Layer ENIG PCB

Quick Turn ENIG PCB Board

Lead free ENIG PCB

MOKOPCB delivers a motto of Redefining Customer Service and that includes all of our ENEPIG circuit board work. Our engineers have decades of combined experience and are able to deliver a guaranteed quality service for every step in your PCB need.

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