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Does this forum covers BGA's

#32726

Does this forum covers BGA's | 18 February, 2005

Lead Free Ball Grid Array packages are expected to be increasing the shipment numbers by 2006. How many guys out there are familiar with the lead fee BGA's and the associated processes? Can some one tell me who is the best and low cost supplier for the lead free solder balls and the best reflow flux suppliers?

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Grant

#32746

Does this forum covers BGA's | 18 February, 2005

Hi,

The normal electronic components you purchase should have lead free variants. Also, all solder paste manufacturers have lead free solder pastes, so you just need to get the paste specification, and then re-profile your oven for it. Temps are higher, so some ovens are not stable at the higher temp, and the process window is much tighter.

It's best not to use lead components in a lead free process.

Regards,

Grant

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#32751

Does this forum covers BGA's | 19 February, 2005

Currently, we see lead-free solderballs on BGA. The issue for us is determining the reliability of these components when using leaded solder.

Most solder materials manufacturers supply lead-free solder balls. Check with your current solder paste supplier.

Search the fine SMTnet Archives for previous discussions on BGA.

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#32758

Does this forum covers BGA's | 21 February, 2005

Thanks Grant and Dave.

I have done extensive work on this and found some of the solder balls and solder flux does match my requirements. We have done many tests and have a good responses for both ceramic and plastic substrates. All is fine as long as it is just lead free with out any lead mix-up. What percentage of this lead mix up is accepted? I guess it should be zero. But sometimes my suppliers can not avoid as we always have customers with leaded requirements and there is a possibility of these solder mix-ups. I am referring to C5-BGA only not C4 flip chip assembly. Also, do you guys know why the same lead free solder behaves differently for electroplated Nickel and electroless Nickel? I see a drastic change in IMC. Any comments? Regards. GV

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#32771

Does this forum covers BGA's | 21 February, 2005

We're try to stay away from using electroless nickel. Please describe the differences between the IMC.

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#32795

Does this forum covers BGA's | 21 February, 2005

Davef, We see increased IMC thickness for electroless Ni and the brittle mode failure occurs much earlier in multiple reflows, exposing IMC layers. Not good for board level reliability.Regards. GV

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#32805

Does this forum covers BGA's | 22 February, 2005

It could be that you're starting with hyper corroded nickel, before you even begin work. With electroless nickel, everybody looks at the nickel, but the cause turns out to be the immersion gold is too aggressive [during fabrication]. Immersion gold works by corroding the nickel. If it is too aggressive, it takes away the nickel and leaves phosphorous behind. This makes it look like the phosphorous level is too high in the nickel bath.

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