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Hot Tear/Shirnk Hole>Will it happen on BGA joint ??

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#55834

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 5 August, 2008

Dear all,

As far as I know hot tear or shrink hole defect only happen at plated though hole soldering, especially for those lead free wave process. Recently, a laboratory engineer had done cross section on some of the SMT BGA ball and IC lead soldering and found some symptom similar to hot tear appear on BGA and IC soldering..You can see "rough cut"(Not a smooth cut appear at the center of the BGA or IC soldering. If not mistaken, this is not a hot tear defect. It could be resulted from improper filing during the cross section process..Do you agree with me?

Thanks, Sean

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#55837

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 5 August, 2008

Dear All,

In order to understand the issue, pls review the photo in the attached file.

Thanks, Sean

Attachments:

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#55868

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 6 August, 2008

We agree that the squigglie part of the section of the BGA ball looks like something other than 'hot tear.' We'd guess that it is an inclusion, but it could be a sectioning defect, as you say.

We agree that the majority of occurances of hot tear are seen in PTH solder connections, but it is also seen in BGA solder connections.

For more on hot tear, look here: http://books.google.com/books?id=y2y4Y9ZPpYkC&pg=PA109&lpg=PA109&dq=hot+tear+lead+free&source=web&ots=6tJO93lCcR&sig=VsyMtAOD6Zs-K7hy0MzEjJI3iBQ&hl=en&sa=X&oi=book_result&resnum=7&ct=result#PPA107,M1

It's amazing to us that the rocket scientists at IPC would give a defect like hot tear a pass. It looks like they're trying too hard to make PbF work. They must be justifying calling hot tear acceptable because it is most prevalent in solder connections with high mass. There's a lot of redundancy in that type of a connection. So, that must make it acceptable. We don't wish they're on the plane, but insist they go the each funeral and explain their decision to each family.

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#55895

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 8 August, 2008

Thanks Davef....How is this defect look like when it appear on BGA?? Is it also a smooth cut? BTW, I really appreciate your help..Sean

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#55896

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 8 August, 2008

Hot tear occurs at the surface of the solder connection. The surface will look like someone tore the surface apart. So, it is a crack or fracture formed prior to metal solidification.

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#55916

Hot Tear/Shirnk Hole>Will it happen on BGA joint ?? | 8 August, 2008

Ok,,,noted..Thanks for help...Rgds Sean

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