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BGA process requirements

#19479

BGA process requirements | 11 April, 2002

A couple of questions to establish a baseline for when the check writers start asking questions........

How many of you have vision systems on site for BGA inspection? If you don't have it, do you do 100% X-ray, or did you just nail down the process, have a second part verify it, and profile your oven a lot, control your paste well, etc.? How many of you have X-ray on site, and how many of you contract it out for process verification? Re: the latter, how often do you send stuff out? I suppose it's dependant on your own requirements, but I currently have no clue, so....

Does anyone contract BGA rework out to someone else with the equipment? That's an option that the powers that be want to consider, although that seems like it might be cost prohibitive.

Right now we plan on using the MPAV to do the BGA placement. The parts we expect to be placing first are .040" pitch. My understanding is that we have BGA ball verification capability on the machine as it is currently configured, but we haven't confirmed it yet. If we don't, is it reasonable to assume that we'll be eating scrap (or rework) at a painful rate? What's the rate of occurrence of damaged, missing, or otherwise crummy balls?

Thanks in advance.....

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Alan

#19483

BGA process requirements | 12 April, 2002

Steve,

I have done BGA work with and with-out Xray. If you are going to install them in high volume it makes sence to have every thing including rework on site. If you are just going to put down several a week you can probably get away without the expense of Xray, especially if you are doing test. Just make sure you have all of your processes under control. Make sure your parts are dry, your paste is good, and your profile is right on etc., and have an Lab do some Xray for you to prove out your process. You also need to have a lot of faith that your operators will not deviate from your process. If you do put in Xray, develop a sampling plan. You can Xray the first five boards 100% and then every 10th board or once every 1/2 hour. I had a board with 32 BGA's on it so we would Xray every board but different locations according to a predetermined plan.

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Matt Kehoe

#19527

BGA process requirements | 16 April, 2002

Have you considered Solid Solder Deposition?

www.sipad.net

mk

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gzweig

#19529

BGA process requirements | 16 April, 2002

In response to questions on BGA Process Requirements and X-ray Inspection please request pdf publication : "Rapid and Effective X-ray Inspection of BGA using Siganture Identification" from : gzweig@glenbrooktech.com

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J. Borrelli

#19531

BGA process requirements | 16 April, 2002

We're currently brining up the BGA process. In instances where we needed to place a BGA for proto run, we subcontracted bga placement to a local organization, but its spendy. Would not want to use for production. We also intend to use an mpav.

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ianchan

#19557

BGA process requirements | 17 April, 2002

what process is that? can kindly describe? is it that technology where bricks of solder are "ready made" deposit onto PCB pads thus eliminating the need to solder paste print/dispense by machine?

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jnunns

#19583

BGA process requirements | 19 April, 2002

We have been doing BGAs for about 3 years in house. We started off with an outside contractor and then brought it in. We are doing a variety of sizes from .05 to .03 pitch. We have 2D capability at print, but do not use it on any but the .03 pitch. The process is fairly robust once you get it down. We have the luxury if in house x-ray, so we inspect at 100%. We also have an ERSA scope to look at the balls. Most of the defects that get to x-ray are due to the chip shooter dropping parts on the BGA sites prior to BGA placement. We have an operator look at the site between the two machines.

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#19587

BGA process requirements | 19 April, 2002

We have been building BGA's for a couple of years. We even use a Universal Omni 4766 to place them with. Reflowing is where I thought we may have problems, Since we have an IR oven. But we bought a .010" thermocouple from Omega to measure the BGA temp underneath the component. It works very well. We use an X-Ray maching that uses film. We are still doing 100% inspection with a mirror around the outside edges and x-ray at rework stations. We've gone down to 25mil pitch so far.

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