Uyemura International Corporation

Eliminating Ni Corrosion in ENIG/ENEPIG Using Reduction-Assisted Immersion Gold in Place of Standard Immersion Gold

Jan 10, 2023 | George Milad, Jon Bengston and Albin Gruenwald

Nickel corrosion in ENIG and ENEPIG is occasionally reported; when encountered at assembly it manifests as soldering failures in ENIG and wire bond lifts in ENEPIG. Although not common, it can be highly disruptive, resulting in missed deliver schedules, supply chain disruption, failure analysis investigations, and liability - all very costly....

EFFECTS OF ENIG NICKEL CORROSION ON WETTING BALANCE TEST RESULTS AND INTERMETALLIC FORMATION

Jan 10, 2023 | Donald Gudeczauskas, George Milad

Since the IPC-4552 rev A for ENIG was introduced there have been many requests for clarification of acceptable and unacceptable levels of nickel corrosion. This paper attempts to further clarify the effects of nickel corrosion on solder wetting balance test results and the resultant intermetallic formed. The study will attempt to produce level 1, level 2, and level 3 corrosion as denoted by IPC-4552 rev A and tabulate wetting balance results and congruity of intermetallic formed....

Comparing Soldering Results of ENIG and EPIG Post Steam Exposure

Nov 15, 2020 | J. Bengston and R. DePoto Uyemura International

ENIG, electroless nickel immersion gold is now a well-regarded finish used to enhance and preserve the solder-ability of copper circuits. EPIG, electroless palladium immersion gold, is a new surface finish also for enhancing and preserving solder-ability but with the advantage of eliminating Electroless Nickel from the deposit layer. This feature has become increasingly important with the increasing use of high frequeny PWB designs whereby nickel's magnetic properties are detrimental. We examine these two finishes and their respective soldering characteristics as plated and after steam aging and offer an explanation for the performance deviation....