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Pb free BGA and Sn Pb solder paste

Vijay

#28427

Pb free BGA and Sn Pb solder paste | 6 May, 2004

Hi, I just need to undestand any issue? If I mount Pb free BGA and use normal SN/Pb solder paste?

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#28431

Pb free BGA and Sn Pb solder paste | 6 May, 2004

Even with PbSn solderpaste the leadfree BGA's have a superior resistance to solder-joint fatigue failure when compared to conventional parts. [Solder Fatigue Reliability Issues in Lead Free BGA Packages, Pedro Chalco of IBM, Pan Pacific Microelectronics Symposium, SMTA, February 4-7, 2002]

Having said that, fatigue may or may not be the point of concern in your assembly.

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#28868

Pb free BGA and Sn Pb solder paste | 1 June, 2004

Any view on what the minimum reflow temperature is for a SAC ball bga to form a reliable joint with PbSn solder?

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Ken

#28875

Pb free BGA and Sn Pb solder paste | 1 June, 2004

profile it for the tin/lead paste.

The tin in the solder paste will begin to disolve the sac ball. This is exactly the same scenario as 90/10 (80/20)high temp balls found on ceramic bga and many super bga devices (except the sac balls are now tin rich rather than lead rich).

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Ken

#28876

Pb free BGA and Sn Pb solder paste | 1 June, 2004

...oops part 2:

I will assume a sac 350 ball??? 217-218C this will completely reflow the ball and form a "normalized" joint with a collapsed structure.

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#28882

Pb free BGA and Sn Pb solder paste | 2 June, 2004

Is there not an issue with reflowign the SAC ball's in term's of drivign up the lead contect in a lead free joint that increases the risk of failure in them? certainly dramatically increases voiding... have some pictures of soem that a customer tried to do at their own plant... not so nice. Sure NEMI has stuff published on mixign leadfree SAC balls with tin/lead paste saying it's really not recomended. Push comes to shove try not to reflow the ball....

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#28902

Pb free BGA and Sn Pb solder paste | 2 June, 2004

Thanks to all on this feedback

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