Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


BGA Reliability

Keith Stone

#20810

BGA Reliability | 22 July, 2002

Hi

Does anyone know of any studies carried out comparing long term reliability of BGAs with their equivalent QFPs etc.

If you were designing a critical product in the aerospace field would you go for the BGA or QFP version of the same IC? Based on what evidence?

All answers gratefully received.

Keith

reply »

#20813

BGA Reliability | 22 July, 2002

There has been books of stuff written on the topic. One expample is: http://nepp.nasa.gov/index_nasa.cfm/476/CD467677-8023-44E3-A795CBCF2DECFF05/

reply »

Keith Stone

#20824

BGA Reliability | 23 July, 2002

Dave

Thanks, some very interesting articles on that link, it really is rocket science!

However this article is a bit of a tease, it tells you how they compared different package types, CBGAs and PBGAs and a fine pitch QFP but does not detail the results for the QFP!

Does any one know of any other links?

Thanks

Keith

reply »

#20826

BGA Reliability | 23 July, 2002

Hell-loooow!!!

Why not contact the document author? Try: Reza Ghaffarian - Reza.Ghaffarian@jpl.nasa.gov Jet Propulsion Laboratory Phone: 818 354-2059 | FAX: 818 393-5245

reply »

#20856

BGA Reliability | 24 July, 2002

Being in the line of BGA rework and having performed much rework on boards that go into military planes, I can give you an opinion from a practical background rather than an in depth study.

Basically BGA's have caused many of my customers big headaches. Especially on military boards that need the PCB's to be glued to a heavy heat sink. It's hard to rework or upgrade a component that has a peak temperature rating of 220C whne you need to heat a board to 300C to overcome the amount of heat the heat sink is dissapating. It would be much easier to remove and hand solder a QFP to this type of assembly. Not to mention the cost of exchanging a BGA around $100.00 and a QFP $10.00. Equipment to rework BGA's start at around $35000.00 and for a QFP it starts at around $1500.00.

In the production stage BGA's appear to be pretty reliable. But in the prototype stage they have been causing many of my customer time to market issues. Mainly by assembly houses or rework houses lacking experience and assmeblying boards with poor profiles, not baking chips, not cleaning water soluble fluxes out from under the package well enough.

BGA's also appear to be more sensitive to black pad or plating contamination on the circuit board or even the BGA substrate itself. We find many BGA's that look acceptable visually and through X ray inspection. Black pad contamination is not visually or X ray detectable. It causes the connection to appear as an open during electrical test. Many people misdiagnose it as a defective BGA component. You can only diagnose this problem by removing the BGA and inspecting the PCB & BGA substrates.

I suggest that if you can use a QFP rather than a BGA, then do so. If you must use a BGA and have problems. Well, more business for me. http://www.repair-pcb.com

reply »

Keith Stone

#20869

BGA Reliability | 25 July, 2002

Dennis

thanks for the feedback. I can confirm we have also had 'black pad' type problems on gold pcbs fitted with BGAs. It can be as you say impossible to detect on Xray. We try to avoid gold pcbs for this reason, preferring horizontal HASL even when fitting fine pitch (0.4mm) QFPs. I have not seen this on the BGA substrate yet....

Regards

Keith

reply »

Juan C. Ruiz

#20904

BGA Reliability | 27 July, 2002

Do you have any picture or reference how can we determine black pad or plating contamination. I have heard about a lot of problems regarding BGA's and normally these components are only replaced or heat it and that's it ,after that the boards are working without any evidence of what was causing the failure.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#20908

BGA Reliability | 28 July, 2002

There's background and links to papers on black pads in the fine SMTet Archives.

reply »

PCB Soldering Tools

SMT Machines china