Thermal modelling and optimisation of hot solder dip process

Stoyanov, Stoyan; Bailey, C.; Tollafield, Peter; Crawford, Rob; Parker, Mike; Scott, Jim; Roulston, John

doi:10.1109/esime.2012.6191763

Cited by 4 publications

(2 citation statements)

References 3 publications

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“…This can potentially induce thermo-mechanical damage such as delamination, and cracking in the die. Previous studies [12] have investigated the temperature change rate and temperature gradient in the refinished components using computational modeling techniques and the results obtained were used to optimize the refinishing process.…”

Section: Introductionmentioning

confidence: 99%

Statistical analysis of the impact of refinishing process on leaded components

Yin

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Bailey

et al. 2015

Microelectronics Reliability

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Refinishing process such as hot solder dip (HSD) process can be used to prevent tin whisker growth in microelectronics components by replacing the lead-free finishes with conventional tin-lead coatings. In some applications, it is also used to ensure reliable solder joints by replacing contaminated finishes and lead-free alloys with tin-lead to result in a homogeneous solder joint with tin-lead paste. In this paper, the impact of a HSD refinishing process on leaded components was statistically studied by comparing the electrical test data of refinished samples with those not-refinished. The likely damage from the component refinishing was thought to be the degradation of package integrity through thermomechanical stressing. This might be detectable as a microscopic leakage current if moisture could be encouraged into any open areas. Ten types of leaded components were selected and samples for each type of the component were allocated into 2 lots, one for refinishing and one used as a control. 150 cycles -65/150°C thermal cycling followed by 500 hours 85%RH/85°C humidity test was applied to all the samples (both refinished and not-refinished) to amplify any incipient failure points and accelerate moisture ingress into the package. Electrical test was then carried out to measure any small changes in current under zero and reverse bias conditions. In the end, a data reduction process in conjunction with a statistical hypothesis test was used to analyze the electrical test data. The results showed that there was no significant difference between the measured currents of refinished and not-refinished postaged samples. Therefore it was concluded that the refinishing process did not have a significant impact on the tested components. This conclusion was further strengthened by other experimental test results such as CSAM images.

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Section: Introductionmentioning

confidence: 99%

Statistical analysis of the impact of refinishing process on leaded components

Yin

Best

Bailey

et al. 2015

Microelectronics Reliability

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“…Previous studies[10][ 11] have predicted the temperature gradients and changing rate in the refmished parts using computational modeling techniques and the results obtained were used to optimize the refinishing process.In this work, the impacts of refmishing process on the reliability performance of microelectronics components have been studied statistically by comparing the electrical test data of the refinished samples with not-refinished ones after the reliability test. The likely failure mechanism was the moisture ingress due to mechanical stressing.…”

mentioning

confidence: 99%

Statistical analysis of the impacts of refinishing process on the reliability of microelectronics components

Yin

Best

Bailey

et al. 2012

2012 13th International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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Tin-whisker induced failures have been one of the major concerns of using electronic components with Sn or Sn-rich lead free solder coated lias. In some applications, this risk can be mitigated by refinishing the lead-free finishes with conventional tin-lead coatings using a solder dipping process.However, the solder dipping process does not come without reliability risks of its own. In this paper, the impacts of a refinishing process on the reliability of microelectronics components were statistically studied by comparing the electrical test data measured from refinished samples with those of not-refinished. A hot solder dipping (HSD) process was used and all the samples (not-refinished and refmished)were subjected to environmental test conditions of 150 cycles -651150°C thermal cycling followed by 500 hours 85%RH/85°C humidity test. Electrical testing was designed to measure the current in reverse or zero bias conditions as currents in these regimes would have a measurable increase if moisture ingress occurs. A data reduction process, in conjunction with statistical hypothesis testing, was used to analyze the electrical test data and the results showed that there was no significant difference between the measured currents of post-aged refinished samples and not-refinished ones. Therefore it was concluded that the refinishing process did not have a significant impact on the reliability performance of the tested components.

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