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Intermetallics and reflow profile


Intermetallics and reflow profile | 2 May, 2000

I am looking for public papers or articles on intermetallic formation as a function of reflow profile. Most solder paste vendors specify peak temperature and time above liquidus, but I am particularly interested in what happens to intermetallic growth above 240 C and 2 - 3 minutes above liquidus. Any information out there?

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Re: Intermetallics and reflow profile | 3 May, 2000

MF: I know of nothing that addresses your question directly. Let me suggest: * Technical types at your solder supplier should be able to help. * "Effect Of Intermetallic Compounds On The Thermal Fatigue Of Surface Mount Solder Joints" PL Tu, et al, IEEE Transactions On Components, Packaging, And Manufacturing - Part B, V 20, No 1, Feb 1997 * Jennie Hwang (her contact points are in SMT Magazine at the end of her articles) is probably the author of texts on soldering with the greatest understanding of solder material properties, including intermetallic formation. She has published curves showing the growth of intermetallics at various temperatures. The temperatures of curves are below reflow temperature.

In addition to your investigation of intermetallics, consider grain size formation as another point of concern.

Good luck Dave F

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