ENIG surface finish of FR4 Printed wiring board

Continued to my last blog, do you know why we want to talk more for Gold surface finish of rigid Boards? I would like to take this chance to share more information for the capability from Best Technology.

Electroless nickel immersion gold (ENIG) is a type of surface plating used for printed circuit boards. It consists of an electroless nickel plating covered with a thin layer of immersion gold, which it can protects the nickel from oxidation. It is also used for welding and applied to contacts (such as keys, gold fingers on memory strips, etc
See attached complexity design for ENIG FR4 printed circuit board.

ENIG has several advantages over more conventional (and cheaper) surface plating such as HASL (solder), including excellent surface planarity (particularly helpful for PCBs with large BGA packages), good oxidation resistance, and usability for untreated contact surfaces such as membrane switches and other contact points. See the complex circuit boards design photo.

ENIG also does not wet as evenly or easily as HASL. In addition, ENIG is a costlier finish, but offers the best characteristics for printed circuit boards. The process requires the most steps compared to other common finishing types.
The thickness of Gold Best Technology conforms to IPC Standard IPC-6013.
Let us see the different for gold finish.

Gold-ENIG
The most important factor the gold serves as barrier and protectant to the nickel.
Advantages of ENIG

Immersion finish = excellent flatness
Good for fine pitch / BGA / smaller components from Samtec/Hirose/Molex
Wire bondable
Good heat dissipation
Long shelf Life (12 months in vacuum pack)

Disadvantages of ENIG
Expensive finish
Black Pad/Black Nickel concerns on BGA
Damage from ET (electronics test)
Signal Loss (RF)
Complicated Process

Gold-Hard Gold

Advantages of ENIG
Hard, Durable Surface
No Pb
Long shelf life

Disadvantages of ENIG
Very Expensive
Extra Processing/ Labor Intensive
Use of more solder Resist/Tape
Plating/ Bus Bars
Demarcation(delamination)
Difficulty with other surface finishes.

As an rich experience PCB manufacturer since 2006, Best Technology always improve its Rigid Circuit boards capability to meet customer requirements, If you have any question about the printed circuit boards (PCBs). Warmly welcome to send mail or call Best Tech.

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