PCB Fabrication

Why Enig Is The Most Popular Surface Finish

by:A-TECH      2020-10-23

Most fashionable floor finishes are lead-free in accordance with RoHS and WEEE directives; a kind of is ENEPIG or Electroless Nickel Electroless Palladium Immersion Gold. According to latest analysis and industry reports, black pad is the result of an excessive degree of phosphorous that’s a byproduct of the dissolution of nickel.

Even non-porous layers will get problems if there is no barrier layer between the gold and copper. There should be a nicely sealed nickel layer (Electroless Nickel-Gold) between the gold and copper. If the nickel is porous, copper atoms migrate by way of the gold to the surface where they oxidize to copper oxide. Obviously, the thing that involves thoughts is some type of contamination.

They were all associated with ENIG related points, in accordance with Kunal Shah, chief scientist at LiloTree which relies within the Seattle area. Currently obtainable ENIG floor finishes are vulnerable to failures related to de-wetting of solder, Shah said, element fall-offs and total malfunction of digital assemblies. This problem may result in electrical continuity failures and result in low-quality performance, and ultimately, product remembers, product performance failures and customer satisfaction points. It can also be a very thin PCB end (between 0.05μm and 0.15μm), making the meeting and soldering course of extra easy and dependable. ENEPIG also shares related benefits to ENIG in that it has a long shelf life as a result of its durability and resistance from tarnishing.

Something has grown underneath the floor, from handling, from an atmosphere, from another course of, from something that was or wasn't carried out within the preliminary board fabrication process where they placed on the gold end. Also, when the solder reflow course of is performed, the intermetallics (interface bonding between solder and floor finish/copper pad) are softer and contain voids because of the phosphorous rich area.

Hence, when any mechanical stress condition is applied, failures occur throughout the intermetallics in a brittle manner. Over the previous few years, LiloTree has worked with several customers to identify the foundation explanation for the sector failures of their merchandise.

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