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ENIG

Researched Information

Here you will find the latest Electroless Nickel / Immerasion Gold (ENIG) presentations, articles, white papers and more.
enig finish pcbs

 

Definition
Provides an electroless nickel / immersion gold finish that can meet the requirements for:

  • Solderability
  • Aluminum wire bonding
  • Electric Contact Surface
  • Multiple Reflows

 

Benefits

  • A planar, solderable finish
  • Good shelf life – Does not tarnish
  • Precious metal electrical contact surface (1.5 million actuations)
  • Al wire bondable
  • Nickel strengthens the PTH – acts as a rivet
  • Nickel barrier prevents copper dissolution during wave solder & rework
  • EMI shield mounting surface
  • Withstands multiple heat cycles well

 

Limitations

  • Expensive
  • Black Pad: Nickel layer prone to crack from mechanical stress

ARTICLES

Getting to the Root Causes of Failures Related to ENIG
Several defects arise after electroless nickelplating that are extreme nuisances. One such issue is “plating in non-plated-through holes” (NPTH). Generally, such a situation occurs because excess palladium catalyst has adsorbed into the NPTH wall and has not been removed by a subsequent process step. Thus, it is quite easy for the electroless nickel to deposit in the catalyzed areas. It is strongly suggested that the first process tank on the electroless nickel immersion gold line be designed to deactivate the palladium in the NPTH that remained from the previous electroless copper process. There are processes commercially available that add little cost to the overall process.
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