Re: BGA's are killing my project




johnspeth@xxxxxxxxx wrote:
Hi everybody-

My project uses several BGA parts. We're in the second board rev stage
(rev 2). Our board manufacturer doesn't seem to be able to 100%
reliably solder those parts down. It makes SW debugging troublesome
because one never knows if the SW or the part is misbehaving. We've
had 15 boards built and I estimate 20% have BGA problems.

I'd like to hear other's experiences with and solutions to BGA
soldering reliability problems. I have a few questions to kick off the
discussion:

Is it a manufacturer process problem that can be totally fixed with
some soldering process improvement? (Corollar: Is my board builder not
up to the task?)

It's a testing and QC/QA issue.


Is this a natural and expected problem that I just have to live with
(result = reduced board yield)?

No. you have to help the board assembler to solve the problem.


How much does the lead-free directive contribute to the problem? (My
rev 2 boards we're built using no-lead solder but rev 1 boards were
built using leaded solder and had the same BGA problems.)

Yes, it does. Lead-free requires higher temperature and more expensive
solder (silver).


Does X-ray inspection *really* identify badly soldered parts 100% of
the time?

Yes, it should help, together with boundary scans. Are they Jtag
scanable?


What is a typical delivered board BGA solder failure rate that you guys
will accept?

Zero, they should go back to be oven.


Thanks for sharing your opinions and experiences.

JJS

.



Relevant Pages

  • Re: How to solder BGAs with reflow oven, and what footprint to use?
    ... I've worked hard to avoid BGA ... should just use round pads centered beneath each ball? ... If I want a via connected to a ball - can I put it on the pad ... I've used a toaster oven to solder these gyro's and it works fine. ...
    (sci.electronics.design)
  • Re: Upgrade of a Pentium III processor - BGA2
    ... If this is a BGA chip, it's not possible without specialized BGA soldering and desoldering tools that will cost tens of thousands of dollars. ... The assembly technology used in modern equipment cannot be repaired without extremely exotic tools. ... They appear to use a low-temp solder for mounting them, ...
    (comp.sys.laptops)
  • Re: BGAs are killing my project
    ... reliably solder those parts down. ... I'd like to hear other's experiences with and solutions to BGA ... I don't use BGA if at all possible so I can't recommend an assembler. ... IME when there is a reliability problem with an assembler and they can't immediately point to QC test results and say "aha!" ...
    (comp.arch.embedded)
  • Re: BGAs are killing my project
    ... The fab houses are having a hell of a problem with the lead free ... My project uses several BGA parts. ... reliably solder those parts down. ... had 15 boards built and I estimate 20% have BGA problems. ...
    (comp.arch.embedded)
  • Re: ARM (or other 32 bit) MCUs in PDIP ?
    ... The large IC on that board looks like a BGA package. ... I presume the trick is to solder it correctly the first time, ... correctly than fine-pitch SMTs, ...
    (comp.arch.embedded)