Evaluation of Effectiveness of Conformal Coatings as Tin Whisker Mitigation

Han, Sang-Wook; Osterman, Michael; Meschter, Stephan J.; Pecht, Michael

doi:10.1007/s11664-012-2179-2

Cited by 28 publications

(14 citation statements)

References 5 publications

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“…The application of polymeric conformal coatings has also been shown to impede the growth of tin whiskers and reduce the risk of electrical short circuits; however, the effectiveness of the most widely used conformal coatings is very much dependent on the thickness of the applied coating [10], which can be considerably reduced at edges and corners [11,12].…”

Section: Introductionmentioning

confidence: 99%

The effect of electroplating parameters and substrate material on tin whisker formation

Ashworth

Wilcox

Higginson

et al. 2015

Microelectronics Reliability

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a b s t r a c tElectroplated tin finishes are widely used in the electronics industry due to their excellent solderability, electrical conductivity and corrosion resistance. However, the spontaneous growth of tin whiskers during service can result in localised electrical shorting or other harmful effects. Until recently, the growth of tin whiskers was successfully mitigated by alloying the tin with lead. However, restriction in the use of lead in electronics as a result of EU legislation (RoHS) has led to renewed interest in finding a successful alternative mitigation strategy.Whisker formation has been investigated for a bright tin electrodeposit to determine whether whisker growth can, at least partially, be mitigated by control of electroplating parameters such as deposition current density and deposit thickness. The influence of substrate material and storage at 55°C/85% humidity on whisker growth have also been investigated.Whisker growth studies indicate that deposition parameters have a significant effect on both whisker density and whisker morphology. As deposition current density is increased there is a reduction in whisker density and a transition towards the formation of large eruptions rather than potentially more harmful filament whiskers. Increasing the tin coating thickness also results in a reduction in whisker density. Results demonstrate that whisker growth is most prolific from tin deposits on brass, whilst that from tin deposits on rolled silver is greater than that observed for tin deposits on copper.

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Section: Introductionmentioning

confidence: 99%

The effect of electroplating parameters and substrate material on tin whisker formation

Ashworth

Wilcox

Higginson

et al. 2015

Microelectronics Reliability

View full text Add to dashboard Cite

show abstract

“…A substantial body of work has been reported on the use of conformal coatings on Sn to minimize whisker growth. [16][17][18][63][64][65] Of several polymeric conformal coats examined on assembled electronic packages, Parylene C coatings have been found to be most effective for suppressing whisker formation. It was further noted that very thin conformal coats were generally unable to contain whisker growth.…”

Section: Legacy Approaches For Whisker Mitigationmentioning

confidence: 99%

Recent Advances in Mitigation of Whiskers from Electroplated Tin

Majumdar

Dutta

Bhassyvasantha

et al. 2019

JOM

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Tin whiskers pose an electrical reliability risk in the form of potential short circuits. This problem was solved in the past by adding a few percent of Pb during Sn electroplating, but with the ban on Pb in Europe and elsewhere, it has resurfaced. While various mitigation strategies have been formulated based on known whisker growth mechanisms, the electronic industry is still awaiting a satisfactory solution to the whisker growth problem in Pb-free electronics. Recent advances in the understanding and mitigation of whiskers are reviewed herein. The effects of various alloying elements/dopants are discussed in terms of the mechanisms that impact whisker growth kinetics and mitigation. Most recently, indium addition to Sn has been found to eliminate whiskers with even better mitigation performance than Pb addition. The mechanisms are discussed, and the important role of indium on the surface oxide and subsurface enrichment is highlighted.

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“…ALD has been studied previously alongside other coating methods and materials, and has been shown to give promising results with regards to tin whisker mitigation, see e.g. 2,24,25 ALD is a gas-phase coating method used to produce ultra-thin films of high uniformity and conformality and is based on surface-controlled and self-saturating adsorption reactions between gaseous precursors and the surface, as shown in Fig. 2.…”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition (ALD) to Mitigate Tin Whisker Growth and Corrosion Issues on Printed Circuit Board Assemblies

Kutilainen¹,

Pudas

Ashworth

et al. 2019

Journal of Elec Materi

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This paper presents the results of a research program set up to evaluate atomic layer deposition (ALD) conformal coatings as a method of mitigating the growth of tin whiskers from printed circuit board assemblies. The effect of ALD coating process variables on the ability of the coating to mitigate whisker growth were evaluated. Scanning electron microscopy and optical microscopy were used to evaluate both the size and distribution of tin whiskers and the coating/whisker interactions. Results show that the ALD process can achieve significant reductions in whisker growth and thus offers considerable potential as a reworkable whisker mitigation strategy. The effect of ALD layer thickness on whisker formation was also investigated. Studies indicate that thermal exposure during ALD processing may contribute significantly to the observed whisker mitigation.

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Evaluation of Effectiveness of Conformal Coatings as Tin Whisker Mitigation

Cited by 28 publications

References 5 publications

The effect of electroplating parameters and substrate material on tin whisker formation

The effect of electroplating parameters and substrate material on tin whisker formation

Recent Advances in Mitigation of Whiskers from Electroplated Tin

Atomic Layer Deposition (ALD) to Mitigate Tin Whisker Growth and Corrosion Issues on Printed Circuit Board Assemblies

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