-
-
News
News Highlights
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Hole Truth: Via Integrity in an HDI World
From the drilled hole to registration across multiple sequential lamination cycles, to the quality of your copper plating, via reliability in an HDI world is becoming an ever-greater challenge. This month we look at “The Hole Truth,” from creating the “perfect” via to how you can assure via quality and reliability, the first time, every time.
In Pursuit of Perfection: Defect Reduction
For bare PCB board fabrication, defect reduction is a critical aspect of a company's bottom line profitability. In this issue, we examine how imaging, etching, and plating processes can provide information and insight into reducing defects and increasing yields.
Voices of the Industry
We take the pulse of the PCB industry by sharing insights from leading fabricators and suppliers in this month's issue. We've gathered their thoughts on the new U.S. administration, spending, the war in Ukraine, and their most pressing needs. It’s an eye-opening and enlightening look behind the curtain.
- Articles
- Columns
Search Console
- Links
- Media kit
||| MENU - pcb007 Magazine
Estimated reading time: 1 minute

The Plating Forum: New Developments in ENIG
Electroless nickel immersion gold (ENIG) has been around the printed circuit industry for more than 25 years. The first version of the IPC-4552 ENIG specification was issued in 2002. Initially, the specification only addressed tin/lead solder; now, lead-free solder, like SAC 305 and its variants, dominate soldering in electronics. Although the occurrence of corrosion was recognized, a better understanding of the defect has led to a series of improvements over time.
Today, it is well established that Ni corrosion occurs in the immersion gold step, and the most important method for eliminating the defect is through process control. ENIG is a complex chemical process with multiple process steps, and each step must be completed successfully before proceeding forward. ENIG remains a very popular surface finish and offers a series of benefits at assembly: it is easy to inspect, has an extended shelf life, and is suitable for a wide range of assembly applications.
The IPC-4552 Rev A, issued in 2017, specifies the deposit thickness: nickel from 3–6 µm (120–240 µnis) and gold from 0.04–0.1 µm (1.6–4.0 µins). The upper limit for gold at 0.1 µm (4.0 µins) would require an extended dwell time in the immersion gold bath. The extended dwell time makes the deposit susceptible to nickel corrosion. The recommended immersion gold deposit thickness is 0.04–0.07 µm (1.6–2.8 µins). If a higher gold thickness is a design requirement, an alternative to immersion gold should be used for deposition. Two available alternatives are reduction-assisted immersion (RAI) gold and electroless gold.
To read this entire column, which appeared in the December 2019 issue of PCB007 Magazine, click here.
More Columns from The Plating Forum
The Plating Forum: Reduction Assisted Immersion Gold for ENEPIG Surface FinishThe Plating Forum: Surface Finish Evolution from Conventional to Advanced
The Plating Forum: Plating in Electronic Applications
The Plating Forum: How the Pandemic Impacted PCB Manufacturing
The Plating Forum: The Significance of IPC ENIG Specification 4552 Revision B
The Plating Forum: The IPC Surface Finish Specifications
The Plating Forum: An Overview of Surface Finishes
The Plating Forum: DIG—The Next Generation