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IPC Conference Raises New Lead-free Reliability Concerns

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Wayne

#49077

IPC Conference Raises New Lead-free Reliability Concerns | 17 April, 2007

Now, they realized the problem of the current leadfree alloys. Is there any leadfree alloys finalized to use in future? Will it be a four elements alloys instead of current three elements alloys (eg SAC)?

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#49080

IPC Conference Raises New Lead-free Reliability Concerns | 17 April, 2007

The only way to resolve these issues is to bring back the good ol� lead and make the joints ductile instead of brittle for an affordable price.

Thanks for the link Dave

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#49081

IPC Conference Raises New Lead-free Reliability Concerns | 17 April, 2007

Or this might be the right solution Alternative lead free soldering reviewed: http://circuitsassembly.com/cms/content/view/4665/95/

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#49100

IPC Conference Raises New Lead-free Reliability Concerns | 18 April, 2007

lol, you see, all our problems will soon be solved with SodiT potatium solder, dont worry!

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#49106

IPC Conference Raises New Lead-free Reliability Concerns | 18 April, 2007

Every failure analysis study I've seen, (and quite a few by now) showes Pb Free failing in about half the time or cycles as Sn/Pb. HALT and HASS testing shows reality- run way from a Pb Free product other than a camcorder, etc...

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blnorman

#49107

IPC Conference Raises New Lead-free Reliability Concerns | 18 April, 2007

For years all our R&D for high temp applications (automotive underhood electronics) has shown that Pb-free, at our max temps, doesn't have the reliability of SnPb. Fortunately, for us, EoLV (End of Life Vehicle) legislation in Europe was enacted before WEEE and RoHS. EoLV gives Pb in solder an exemption with no expiration date. That's the main reason we haven't seen the push that other electronic applications have.

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Wayne

#49153

IPC Conference Raises New Lead-free Reliability Concerns | 19 April, 2007

Agreed. Like I mentioned it before, all the leadfree solders are currently for consumer products. Military, aerospace & some automotive industry haven't implemented leadfree yet. They are still study which to go! Maybe by that time (finalized which to use), then we all can follow their standard and having high reliability products!

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Bob R.

#49163

IPC Conference Raises New Lead-free Reliability Concerns | 20 April, 2007

I'm in the high reliability (exempt) sector and have thermal cycled hundreds of boards in the past few years. As far as which is more reliable, SnPb or SAC305, my data is similar to what the technical literature is saying, "It Depends". In low strain situations such as small components, QFPs, SOICs, large pitch BGAs, etc, SAC305 has similar performance to SnPb. In high strain situations such as large ceramic discretes, certain QFNs, etc, SAC305 is dramatically less reliable than SnPb. Something I've noticed is that even in parts that have equivalent fatigue life between SnPb and SAC305, the SAC305 joints have earlier crack initiation. Regardless of when the joint fails electrically, our customers don't like seeing cracks in cross-sections taken from units pulled from validation at 1/3 the expected life. The big question that hasn't been adequately addressed is acceleration factor. Some data is showing that SAC305 has a higher acceleration factor so, in theory, it can fail a thermal cycle test earlier than SnPb but still have a longer field life.

We can design around a lot of the fatigue issues. The thing that worries me more is Sn whiskers. We (the high reliability sector) don't have enough pull to force component makers keep supplying non-Sn finishes or use expensive mitigation such as nickel barriers.

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#49197

IPC Conference Raises New Lead-free Reliability Concerns | 20 April, 2007

Here�s another article on lead free solder joint embrittlement

http://uic.com/wcms/WCMS2.nsf/index/Resources_75.html

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