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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


BGA open pin

Sal

#1938

BGA open pin | 12 February, 2000

Experiencing a problem with a 208 PBGA device. I am achieving good wetting with the exception of one ( damn) pin on the outer corner.I have a really good profile but the worrying thing is that it is so inconsistant. Once this open pin failure is detected on the ICT the product is taken over to the BGA rework machine and the device is reflowed hence curing the problem. The product has been runnig for some time now and the problem has just appeared. The device is placed on a N-TEK finished board with no high mass areas around the device, the coplanarity of the bareboard looks good,paste height is consistant,no evidence of corner of the device warping Different bga date codes have been tryed but still the same inconsistancy. Thanks in advance

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Dean

#1939

Re: BGA open pin | 13 February, 2000

Without further information my first guess would be lack of flux to "cut through" the ENTEK layer. Question: In X-ray is the suspect ball of equal diameter when compared to adjacent balls? If no then the volume of solder is different which would point to solder print (no flux via solder paste). How about Via solder scavenging (thieving)?

Also, is this functional, flying probe or ATE testing. Maby its a pin-probe contact problem? My test dept kept bring me boards for rework...after loging in 3 Remove and replaces in a row for U2400. I went to the ATE fixture and found flux on the probe for that BGA node. Just a thought.

hope this helps.

Dean

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Casey Scheu

#1940

Re: BGA open pin | 15 February, 2000

Sal, This is a common problem experienced by several OEM's. It all comes down to heat. This is why the problem is corrected on your repair unit. I would suggest using a Slim Kic or Data Pac (mole) to thermal couple the IC prior to the reflow oven. The best thing is to get accurate data. When checking the oven profile be sure to check the individual IC's, not just the oven's air tempature. If this problem has just appeared it may be an issue with the heating elements in the oven. If you would like to discuss this further please call 305-451-4722. www.apecorp.com Casey Scheu

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