Effect of Solder Flux Residues on Corrosion of Electronics

Kirsten Stentoft Hansen (Invited author), Morten Stendahl Jellesen (Invited author), Per Møller (Invited author), Peter Jacob Schwencke Westermann (Invited author), Rajan Ambat (Invited author)

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearch

Abstract

Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA[a]. ‘No Clean’ fluxes typically contain about 2 wt%[b] solids, 96 wt% alcohol, 1 wt% water and 1 wt% additives. It is assumed that all aggressive additives and solids (acids and ester oil compounds) evaporate during the solder process, which is the reason for the name ‘No Clean’, which means that no cleaning after the solder process is required. In some cases, however, this statement is not correct. Experiments with ‘No Clean’ wave solder flux have been performed, and the results show, that the solder temperature plays an important role; temperatures below 170°C cause more flux residues than solder temperatures above about 235°C. The reason is that the acid part of the flux does not evaporate completely at the lower temperatures, and as acid can be dissolved in water, leakage currents[c] and product failures can occur in humid environments. Also remaining ester oil can act as a site for entrapment of dust, which can act as a humidity absorber. The experiments have been made on SnPb wave solder flux, later experiments will show if the problems are less for Lead-free reflow and wave soldering, because the solder temperature is about 20°C higher. Furthermore an example of failure after humidity testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper.
Original languageEnglish
Title of host publicationAnnual Reliability and Maintainability Symposium, 2009. RAMS 2009.
PublisherIEEE Press
Publication date2009
ISBN (Print)978-1-4244-2508-2
DOIs
Publication statusPublished - 2009
EventRAMS - Las Vegas
Duration: 1 Jan 2008 → …

Conference

ConferenceRAMS
CityLas Vegas
Period01/01/2008 → …

Keywords

  • leakage current
  • flux residues
  • no-clean flux
  • corrosion reliability

Cite this

Hansen, K. S., Jellesen, M. S., Møller, P., Westermann, P. J. S., & Ambat, R. (2009). Effect of Solder Flux Residues on Corrosion of Electronics. In Annual Reliability and Maintainability Symposium, 2009. RAMS 2009. IEEE Press. https://doi.org/10.1109/RAMS.2009.4914727
Hansen, Kirsten Stentoft ; Jellesen, Morten Stendahl ; Møller, Per ; Westermann, Peter Jacob Schwencke ; Ambat, Rajan. / Effect of Solder Flux Residues on Corrosion of Electronics. Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.. IEEE Press, 2009.
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title = "Effect of Solder Flux Residues on Corrosion of Electronics",
abstract = "Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA[a]. ‘No Clean’ fluxes typically contain about 2 wt{\%}[b] solids, 96 wt{\%} alcohol, 1 wt{\%} water and 1 wt{\%} additives. It is assumed that all aggressive additives and solids (acids and ester oil compounds) evaporate during the solder process, which is the reason for the name ‘No Clean’, which means that no cleaning after the solder process is required. In some cases, however, this statement is not correct. Experiments with ‘No Clean’ wave solder flux have been performed, and the results show, that the solder temperature plays an important role; temperatures below 170°C cause more flux residues than solder temperatures above about 235°C. The reason is that the acid part of the flux does not evaporate completely at the lower temperatures, and as acid can be dissolved in water, leakage currents[c] and product failures can occur in humid environments. Also remaining ester oil can act as a site for entrapment of dust, which can act as a humidity absorber. The experiments have been made on SnPb wave solder flux, later experiments will show if the problems are less for Lead-free reflow and wave soldering, because the solder temperature is about 20°C higher. Furthermore an example of failure after humidity testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper.",
keywords = "leakage current, flux residues, no-clean flux, corrosion reliability",
author = "Hansen, {Kirsten Stentoft} and Jellesen, {Morten Stendahl} and Per M{\o}ller and Westermann, {Peter Jacob Schwencke} and Rajan Ambat",
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language = "English",
isbn = "978-1-4244-2508-2",
booktitle = "Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.",
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Hansen, KS, Jellesen, MS, Møller, P, Westermann, PJS & Ambat, R 2009, Effect of Solder Flux Residues on Corrosion of Electronics. in Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.. IEEE Press, RAMS, Las Vegas, 01/01/2008. https://doi.org/10.1109/RAMS.2009.4914727

Effect of Solder Flux Residues on Corrosion of Electronics. / Hansen, Kirsten Stentoft (Invited author); Jellesen, Morten Stendahl (Invited author); Møller, Per (Invited author); Westermann, Peter Jacob Schwencke (Invited author); Ambat, Rajan (Invited author).

Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.. IEEE Press, 2009.

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearch

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T1 - Effect of Solder Flux Residues on Corrosion of Electronics

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AU - Jellesen, Morten Stendahl

AU - Møller, Per

AU - Westermann, Peter Jacob Schwencke

AU - Ambat, Rajan

PY - 2009

Y1 - 2009

N2 - Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA[a]. ‘No Clean’ fluxes typically contain about 2 wt%[b] solids, 96 wt% alcohol, 1 wt% water and 1 wt% additives. It is assumed that all aggressive additives and solids (acids and ester oil compounds) evaporate during the solder process, which is the reason for the name ‘No Clean’, which means that no cleaning after the solder process is required. In some cases, however, this statement is not correct. Experiments with ‘No Clean’ wave solder flux have been performed, and the results show, that the solder temperature plays an important role; temperatures below 170°C cause more flux residues than solder temperatures above about 235°C. The reason is that the acid part of the flux does not evaporate completely at the lower temperatures, and as acid can be dissolved in water, leakage currents[c] and product failures can occur in humid environments. Also remaining ester oil can act as a site for entrapment of dust, which can act as a humidity absorber. The experiments have been made on SnPb wave solder flux, later experiments will show if the problems are less for Lead-free reflow and wave soldering, because the solder temperature is about 20°C higher. Furthermore an example of failure after humidity testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper.

AB - Flux from ‘No Clean’ solder processes can cause reliability problems in the field due to aggressive residues, which may be electrical conducting or corrosive in humid environments. The solder temperature during a wave solder process is of great importance to the amount of residues left on a PCBA[a]. ‘No Clean’ fluxes typically contain about 2 wt%[b] solids, 96 wt% alcohol, 1 wt% water and 1 wt% additives. It is assumed that all aggressive additives and solids (acids and ester oil compounds) evaporate during the solder process, which is the reason for the name ‘No Clean’, which means that no cleaning after the solder process is required. In some cases, however, this statement is not correct. Experiments with ‘No Clean’ wave solder flux have been performed, and the results show, that the solder temperature plays an important role; temperatures below 170°C cause more flux residues than solder temperatures above about 235°C. The reason is that the acid part of the flux does not evaporate completely at the lower temperatures, and as acid can be dissolved in water, leakage currents[c] and product failures can occur in humid environments. Also remaining ester oil can act as a site for entrapment of dust, which can act as a humidity absorber. The experiments have been made on SnPb wave solder flux, later experiments will show if the problems are less for Lead-free reflow and wave soldering, because the solder temperature is about 20°C higher. Furthermore an example of failure after humidity testing and use in the field, consequences and recommendations are given. Failures, caused by harsh[1] customer environments, are not covered in this paper.

KW - leakage current

KW - flux residues

KW - no-clean flux

KW - corrosion reliability

U2 - 10.1109/RAMS.2009.4914727

DO - 10.1109/RAMS.2009.4914727

M3 - Article in proceedings

SN - 978-1-4244-2508-2

BT - Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.

PB - IEEE Press

ER -

Hansen KS, Jellesen MS, Møller P, Westermann PJS, Ambat R. Effect of Solder Flux Residues on Corrosion of Electronics. In Annual Reliability and Maintainability Symposium, 2009. RAMS 2009.. IEEE Press. 2009 https://doi.org/10.1109/RAMS.2009.4914727