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Lead Free soldering profile for SMT

Kevin Yeoh

#24725

Lead Free soldering profile for SMT | 6 June, 2003

Hi all,

I am just wondering is there any other Lead Free Standard Profile for IR reflow besides the standard provided by Jedec ?

What if the profile that i use is different from the one provided by jedec ? Lets say the peak temperature for Jedec is about 240'C while the one i'm using is 260'C ?

Can I still qualify my product as lead free base on the profile which is different from Jedec standard ?

Hope that my question is clear and will appreciate any help available to clarify this matter.

thanks a lot in advance !

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#24726

Lead Free soldering profile for SMT | 6 June, 2003

Which specific JEDEC standard are you talking about? It's very peculiar that JEDEC would publish such a standard.

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JohnW

#24727

Lead Free soldering profile for SMT | 6 June, 2003

Hi Kevin,

the profile doesn't actually qualify something as lead free or not it's purely the Pb content of the assembly that does this. Currently the understanding of the limitations of the lead in the jont is 0.1% by weight or less. So as long as your product meet's this specification you basically have a lead free product. Now that sounds simple but it's really not when you add the various finishes of the components and the PCB etc etc. What you do have to look for in term's of your profile is that the devices on the card are rated to take your 260 deg profile, at the moment most are unlikely to be as in general the suppliers are working to the IPC 020b std and rating to 240 deg C so technically your overcooking your devices and risking any warranty. Not all of the cmponent suppliers are limited to 240, some have rated devices at 260 but not many. NEMI are pushing for devices to be allowed at least 1 reflow cycle at 260 deg C so when it comes to repair of a BGA for example you have soem room to play with.

hope this helps

John

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Marc Peo

#24730

Lead Free soldering profile for SMT | 6 June, 2003

Kevin,

Agree with John's thoughts on profiling and the max temp of 240 degrees in particular. To add to it a bit we have seen the following parameters put in place at many assembly houses to protect against overcooking the components:

--Time above 230 deg < 30 sec --Time above 200 deg < 60 sec

Our Japanese clients are especially focused on the time above 200 deg as an important data point for component longevity.

Hope this helps.

Marc

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MA/NY DDave

#24733

Lead Free soldering profile for SMT | 6 June, 2003

Hi

John I believe gave a good answer with cautions.

The .001 or .1% is the main criteria that internationally means you are Lead-free per JEITA, the EU and NEMI.

They sat around at a table and decided is how they got the .1%

John did note that you better be careful since although you might be Lead-free you might be blowing your reliability with higher process temperatures.

YiEngr, MA/NY DDave

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Kevin Yeoh

#24734

Lead Free soldering profile for SMT | 7 June, 2003

J-STD-020 Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices.

There's a profile for Lead Free and another for normal Sn/Pb.

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MA/NY DDave

#24736

Lead Free soldering profile for SMT | 8 June, 2003

Hi

Gee I got computer crashed at my last try. I am glad to see my note got through pointing you to the other contributors.

One thought about that profile they give is that they JEITA or Jedec or ??? with a J is striving to balance what they know about components and No Lead "Lead-free" solders to the least damage possible with good soldering.

The profile in the way I look at things is a best process recommendation not a real requirement. The .1% by weight is their requirement by international agreement.

I have seen some disagreement over the profile.

Now MSL which another noted is something, you better check out. I think this is the 020 standard.

YiEngr, MA/NY DDave

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Kris

#24767

Lead Free soldering profile for SMT | 11 June, 2003

Hi,

The percentage of lead (0.1% or otherwise) is still being debated in the EU where the legislation is in place. The industry is pushing for a 0.2% limit,(if lead-free has to be) as it is considered a limit where solder can be recycled economically. Apart from the EU legislation I do not know if JEITA or NEMI are recommending any limits. I belive they will just follow the legislation in Europe.

Thanks

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MA/NY DDave

#24785

Lead Free soldering profile for SMT | 11 June, 2003

Hi

Yes Thanks,

I understand that there are still some arguments going on in the EU and some companies like Phillips AG, I believe, are championing changes. Even so from what I know the combined JEITA/European (Soldertec) /USA NEMI task group is still calling Lead Free <.1%wt

So we are right about the <.1% kind of, if we use the EU as a base and more so if we use Japan's Tree Leaf.

YiEngr, MA/NY DDave

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MA/NY DDave

#24786

Lead Free soldering profile for SMT | 11 June, 2003

Hi

I had to poke around awhile to see what you meant.

I think you were at an advanced level where IF he knew the MSL ratings of his devices he should constrain his profile within the component mfgs tests for exposure to various profiles, or at least understand how these inter relate.

Whew, I don't think our topic starter is at this point.

YiEngr, MA/NY DDave

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