Effect of Gold on the Corrosion Behavior of an Electroless Nickel/Immersion Gold Surface Finish

Bui, Quang Tri; Nam, Nguyễn Đăng; Yoon, Jeong‐Won; Choi, Don-Hyun; Kar, Abhijit; Kim, J G; Jung, Seung‐Boo

doi:10.1007/s11664-011-1682-1

Cited by 13 publications

(6 citation statements)

References 30 publications

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“…Electroless nickel immersion gold (ENIG) is the leading surface finish used in electronic industries, among other types of final finishing such as hot air solder levelling, organic solderability preservatives, immersion tin, immersion silver, etc. ENIG consists of a bi-layered metallic coating of Ni and Au to protect the Cu traces [10,11]. ENIG is characterised by high resistance to corrosion and whisker growth, excellent electrical conductivity and solderability, and represents a lead-free, environmentally friendly fabrication process [1,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Localised aqueous corrosion of electroless nickel immersion gold-coated copper

Mousavi

Kosari

Mol

et al. 2022

Corrosion Engineering, Science and Technology

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Electroless nickel (Ni) immersion gold (Au), commonly referred to by the acronym ENIG, is the most common protective coating applied on the exposed copper (Cu) traces of printed circuit boards (PCBs). In this work, we elucidate the local corrosion mechanism of the ENIG-Cu system by applying microscopic, surface analysis and electrochemical techniques with high spatial resolution to provide a comprehensive understanding of the complex local corrosion mechanism of the ENIG-Cu system. The corrosion initiation is highly localised and associated with pores or micro-defects in the Au layer. The corrosion initiates by the dissolution of the underlying Ni layer, being less noble than Au. The dissolution propagates in lateral and perpendicular directions relative to the surface in an elliptical fashion. With time, the direction of corrosion propagation changes to a predominantly lateral attack of the Ni layer. The corrosion process is governed by the cathode/anode ratio of the Au/Ni galvanic couple.

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Section: Introductionmentioning

confidence: 99%

Localised aqueous corrosion of electroless nickel immersion gold-coated copper

Mousavi

Kosari

Mol

et al. 2022

Corrosion Engineering, Science and Technology

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“…However, to the best of our knowledge, there are no such reported methods for making ENIG finish PCB electrodes more electroactive. With suitable development, the gold surface in ENIG finish PCBs does offer protection against corrosion [24]. However, surface preparation strategies to create biosensors, especially immunosensors, with ENIG finish PCBs used directly as substrate for functionalization remain unexplored.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Immunosensor Platform Using Low-Cost ENIG PCB Finish Electrodes: Application for SARS-CoV-2 Spike Protein Sensing

et al. 2021

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In recent years, lab-on-chip systems based on printed circuit board (PCB) substrates are gaining attraction primarily due to their low cost of manufacturing. Adapting inexpensive PCBs for development of immunosensors usually requires additional processing steps such as gold electroplating and electropolymerisation, that add to the manufacturing costs. In this work, we demonstrate methods to leverage electroless nickel immersion gold (ENIG) finish PCBs as electrodes for developing electrochemical immunosensors. We evaluated the performance of various parameters that impact sensor performance such as methods to clean impurities on PCB surface, optimization of redox probe concentration, and have successfully immobilized antibodies on the electrodes with cysteamine + glutaraldehyde aided process. Based on these methods, we demonstrate an application of ENIG finish PCB electrodes for detection of SARS-CoV-2 spike protein spiked in artificial saliva samples.INDEX TERMS ENIG PCB, immunosensor, functionalization, SARS-CoV-2, spike protein.

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“…Applying a thin layer of gold is a commonly employed way of protecting electric circuits such as printed circuit boards (PCBs) in the electronics packaging industry. A coating method termed electroless nickel immersion gold (ENIG) has gained particular popularity because it provides a substrate with excellent electrical conductivity, corrosion resistance, and good solderability. − In the process, nickel–phosphorus (Ni–P) is first deposited on a copper substrate via electroless plating, and afterward, gold is coated on the Ni–P through galvanic displacement reaction, known as immersion gold (IG). , Traditionally, a reaction solution for IG, or simply IG bath, contains cyanide in the form of potassium dicyanoaurate (KAu(CN) 2 ) because it enables outstanding bath stability and results in superb coating performance. , Because of its highly toxic nature, however, its use has been substantially curbed in recent years. , Alternatives, involving a noncyanide bath, are being actively sought and developed.…”

Section: Introductionmentioning

confidence: 99%

Thiourea-Based Extraction and Deposition of Gold for Electroless Nickel Immersion Gold Process

Son

Hong

Yavuz

et al. 2020

Ind. Eng. Chem. Res.

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Gold electroless plating for surface finishing of electronic circuits, named electroless nickel immersion gold (ENIG), is widely practiced in the electronics packaging industry. Noncyanide substitutions of the current cyanide bath for immersion gold are being sought for environmental and safety reasons. Herein, as a promising option, a bath using a noncyanide gold complex, Au(I)–thiourea, was developed. The kinetics of gold deposition were estimated with respect to gold concentration, thiourea concentration, pH, and temperature; the transfer coefficient of gold concentration and activation energy were found to be 0.697 and 36.69 kJ·mol–1, respectively. In addition, the quality of gold coating in terms of corrosion resistance was verified by electrochemical analysis. The relationship between particle size and corrosion resistance of the coating was confirmed by morphology observation through scanning electron microscopy and Tafel plots. The corrosion potential of the gold layer with thiourea was found to be −62 mV, close to that of the layer using a thiosulfate–sulfite bath, with an advantage of faster deposition rate. The results suggest Au(I)–thiourea can serve as an eco-friendly and field-implementable option for the ENIG process, helping to realize a closed-loop process of gold: recovering the precious metal from electronic wastes and reusing it in new products.

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Effect of Gold on the Corrosion Behavior of an Electroless Nickel/Immersion Gold Surface Finish

Cited by 13 publications

References 30 publications

Localised aqueous corrosion of electroless nickel immersion gold-coated copper

Localised aqueous corrosion of electroless nickel immersion gold-coated copper

Electrochemical Immunosensor Platform Using Low-Cost ENIG PCB Finish Electrodes: Application for SARS-CoV-2 Spike Protein Sensing

Thiourea-Based Extraction and Deposition of Gold for Electroless Nickel Immersion Gold Process

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