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In situ imaging of microstructure formation in electronic interconnections.

ABSTRACT: The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as examples, we show that the interfacial Cu₆Sn₅ layer is present within 0.05?s of wetting, and explore the kinetics of flux void formation at the interface between the liquid and the Cu₆Sn₅ layer. Quantification of the nucleation locations and anisotropic growth kinetics of primary Cu₆Sn₅ crystals reveals a competition between the nucleation of Cu₆Sn₅ in the liquid versus growth of Cu₆Sn₅ from the existing Cu₆Sn₅ layer. Direct imaging confirms that the ?-Sn nucleates at/near the Cu₆Sn₅ layer in Sn-3.0Ag-0.5Cu/Cu joints.

SUBMITTER: Salleh MA

PROVIDER: S-EPMC5227712 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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In situ imaging of microstructure formation in electronic interconnections.

Salleh M A A Mohd MA Gourlay C M CM Xian J W JW Belyakov S A SA Yasuda H H McDonald S D SD Nogita K K

Scientific reports 20170112

The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as examples, we show that the interfacial Cu6Sn5 layer is present within 0.05 s of wetting, and explore the kinetics of flux void formation at the interface between the liquid and the Cu6Sn5 layer. Quantification of the nucleation l ...[more]

PMID: 28079120

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