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Can I use lead free BGA parts in a lead based process?

Grant

#29079

Can I use lead free BGA parts in a lead based process? | 13 June, 2004

Hi,

We have been offered some lead free BGA parts in place of normal lead solder BGA parts in our process, and because we can get them faster it would be a good option.

However does anyone know if we can use them as normal. I assume the balls won't collapse correctly, however if we have led based solder paste, then at least the solder paste should reflow as normal and connect the balls to the pads. Is this a correct assumption?

Are we risking too much. Would we need to go fully led free to use led free parts? In that case, do we need to convert all our components to led free to move to led free?

Regards,

Grant

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Grant

#29080

Can I use lead free BGA parts in a lead based process? | 13 June, 2004

Hi,

Oops, looks as though this has already been covered in another thread. However it was not clear if anyone's done this, and if it worked ok. We only need to do a few hundred boards.

Regards,

Grant

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Ken

#29084

Can I use lead free BGA parts in a lead based process? | 13 June, 2004

If the balls are SAC then you may actually reflow them at 217C. Of course, I may be assuming they are SAC...

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RDR

#29100

Can I use lead free BGA parts in a lead based process? | 14 June, 2004

Yes you can, we have done it for years.

Russ

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Grant

#29111

Can I use lead free BGA parts in a lead based process? | 15 June, 2004

Hi,

Great, and thanks for the info, it's a big help to know someone's actually done it, and so we will give it a try on a few dozen product, and see what happens!

Thanks again for the reply!

Regards,

Grant

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#29116

Can I use lead free BGA parts in a lead based process? | 15 June, 2004

There was a thread in the IPC TechNet a few days ago about this subject. Basic conclusion was that there is a reliablility concern if the lead free balls don't reach liquidus with the Pb profile. Haven't tried it myself. John Thorup

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RDR

#29118

Can I use lead free BGA parts in a lead based process? | 15 June, 2004

John, is this regarding any certain alloy of the ball?

Thanks

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#29132

Can I use lead free BGA parts in a lead based process? | 15 June, 2004

I don't recall if a specific alloy was mentioned just that most lead free alloys would not melt with a Pb profile and result in a less reliable joint in the long term. There was also concern about tin whiskers. Try the archives at http://www.ipc.org for tech net. It ran about the 10th of this month. Also try the fine archives in this forum John Thorup

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#29139

Can I use lead free BGA parts in a lead based process? | 16 June, 2004

If you did not increase your heat to melt the lead free BGA balls, I would be very concerned.

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RDR

#29140

Can I use lead free BGA parts in a lead based process? | 16 June, 2004

Am I getting confused here? What about the the CBGA packages that we have been doing for 5-6 yrs? We never reflowed those balls since we couldn't due to the alloy. I have been informed that if you increase paste volume to ensure a full fillet around the ball you shouldn't have any issues I don't know if that's right or wrong but we have never experienced failures from this process. As more food for thought, on those CBGA packages it should be noted that the hightemp balls were attached with a eutectic solder that does reflow while the ball does not. Also what about all of the solder terminations that have been lead free for several years now that haven't been ID'd as "pbfree" that have been run with 63/37? Are we going to be able to discern between lead and lead (leed)? when we start talking about this stuff?

Very curious and ignorant

Russ

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Grant

#29166

Can I use lead free BGA parts in a lead based process? | 17 June, 2004

Hi,

I agree, and this is why I wondered what peoples experiences were, and it is a bit confusing.

Regards,

Grant

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#29180

Can I use lead free BGA parts in a lead based process? | 18 June, 2004

Shouldn't be a problem. The issue is when we go to Pb-Free pastes with Pb-bearing components.

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RDR

#29182

Can I use lead free BGA parts in a lead based process? | 18 June, 2004

Damn, we are doing that too! What is the issue there? Russ

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Ken

#29183

Can I use lead free BGA parts in a lead based process? | 18 June, 2004

The problem is lead enrichment regions forming in the hottest part of the joint. The lead pool is the weakest part of the (SMT) joint.

In TH interconnects hot tear or pad lift can result. I have recently seen this first hand.

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