X-Ray Criteria for BGA Solder Ball

It all depends where the voids are, and that's tough to do with a transmission x-ray. One needs to be able tilt the assembly at 45-degrees during x-ray, so you can get an idea where the void is. Or, you spend some big bucks for an x-ray laminography machine.

That being said, the IPC is about to release the "A" revision of the IPC-7095, "Design and Assembly Process Implementation for BGA's" It's got a whole section about voiding, and goes into great detail about what voids are acceptable, and what is not. Go to:

http://www.ipc.org/committeedetail.asp?Committee=5-21F

and then click on "Drafts". A window will open, and you can download the 4th ballot draft of the standard. It's a draft now, but I imagine it will be released soon...probably as you see it in the draft. In any case, I recommend you download it. It's a 2.5mb zipped *.PDF file, and has lots of really good information in it.

-Steve Gregory-

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It all depends where the voids are, and that's tough to do with a transmission x-ray. One needs to be able tilt the assembly at 45-degrees during x-ray, so you can get an idea where the void is. Or, you spend some big bucks for an x-ray laminography machine.

That being said, the IPC is about to release the "A" revision of the IPC-7095, "Design and Assembly Process Implementation for BGA's" It's got a whole section about voiding, and goes into great detail about what voids are acceptable, and what is not. Go to:

http://www.ipc.org/committeedetail.asp?Committee=5-21F

and then click on "Drafts". A window will open, and you can download the 4th ballot draft of the standard. It's a draft now, but I imagine it will be released soon...probably as you see it in the draft. In any case, I recommend you download it. It's a 2.5mb zipped *.PDF file, and has lots of really good information in it.

-Steve Gregory-

reply »