PCB Fabrication

High Performance And Optimum Design Of Structures

by:A-TECH      2020-11-02

Compared to other forms of floor finishes, ENIG and ENEPIG present the best solderability for PCBs but the cost is far higher. The difference between manufacturing processes of ENIG and ENEPIG may be found in Figure three under. These circuit boards must survive the rigors of different operational environments.


Electroless nickel immersion gold is a RoHS grievance floor end that gives a reliable solder joint, a planar floor, and is resistant to environmental storage situations, handling and so on. ENEPIG is a surface end manufactured from three metallic layers; first a layer of electroless nickel, then a layer of electroless palladium, and at last a layer of immersion gold.


There are many solderable surface finishes used on copper printed circuit boards that range from thin organic coatings to heavy steel plates, corresponding to 1–3 microns of gold plate. Plated tin-lead or molten tin-lead coatings are early predecessors of the diversified finishes which might be obtainable at present. These leaded alloys constantly present high resistance to steam getting older and solder quality retention. Currently, all other final floor finishes for PCBs fail to keep up acceptable solderability performance after one-hour steam exposure.


The nickel is a hundred and fifty to 200 micro-inches thick, the palladium is usually eight to 15 micro-inches thick (though sometimes 4 to eight micro-inches), and the gold is 1 to 2 micro-inches thick. ENEPIG is suitable for all widespread kinds of wire-bonding and suitable for soldering, providing a major benefit over ENIG and soft bondable gold in applications that require each soldering and wire-bonding. Some designers choose ENEPIG to stop the potential ENIG high quality concern called “black pad”, though black pad has become very rare in recent times. ENEPIG can be used to provide a thinner finish than delicate bondable gold in very fine pitch functions, but this use is more widespread in semiconductors than in printed circuit boards.


Among PCB manufacturing applied sciences, applied sciences contributing to surface finishes play a crucial position in PCB meeting and circuit board product utilization. Copper layer on PCB tends to be oxidized within the air with copper oxidation layer generated which is able to significantly reduce soldering high quality.


The ENIG is a common acronym that stands for Electroless Nickel Immersion Gold. As the recent air solder leveling, additionally it is a floor end of the printed circuit board business.


The ENIG obtained its name as a result of it comprises electroless nickel plating, which is coated with a slim layer of immersion gold. Continuously, it has secured market share resulting from its capability to be versatile in various part assembly processes. ENIG, short for Electroless Nickel Immersion Gold, consists of electroless nickel plating coated with a skinny layer of immersion gold, which protects the nickel from oxidation. ENEPIG, also referred to as Electroless Nickel Electroless Palladium Immersion Gold, differs from ENIG in that a layer of palladium is applied as a resistance layer to stop nickel from oxidation and diffusion to copper layer.


Hence, these circuit boards are coated with surface finishes of assorted sorts. There is a copper layer on a PCB which oxidizes, when it comes in contact with air. Surface finishes assist scale back oxidizing, as well as contribute to solderability, and electrical performance. There are numerous types of floor finishes available available in the market. In this publish, we will consider one such necessary variant – immersion gold surface finish.

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