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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Poor Wetting On The BGA.

Views: 18339

#76483

Poor Wetting On The BGA. | 19 October, 2016

Hi All, Currently im seeing a cold solder/ poor wetting underneath the BGA Ball as i shown in the attachment. From the attachment you also can see one ball with poor wetting and another ball with a good wetting. When i checked with my re-flow profile temperature, the peak temperature of a component was on 253*C. I was in doubt why the one of the ball found poor wetting but another ball beside it has a good wetting? Have anyone have encountered this this before and may i know how you resolved it.

Attachments:

reply »

#76485

Poor Wetting On The BGA. | 20 October, 2016

You say, "... re-flow profile temperature, the peak temperature of a component was on 253*C."

Questions are: * I assume that was the temperature of the component body. What was the temperature of the solder ball? * How does the temperature on the properly soldered ball compare with the defective ball? * What is the breadth and scope of this issue? * What methods were used to control the quality of the solder paste? * How long was the solder paste on the board before completing reflow?

reply »

#76490

Poor Wetting On The BGA. | 21 October, 2016

Looking at your picture I'm not sure you have a wetting problem. Who determined it's not wetted? Are you having functional failures? Is this an isolated incident? What was your TAL? Is the pad on the suspect ball possibly smaller than the others, or connected to a ground plane?

reply »

#78881

Poor Wetting On The BGA. | 15 September, 2017

Dear Thanesh, did You alrady solved issue? We are facing same problems... Unfortunately reject rate is too small to find something wrong directly in production...

reply »

#78891

Poor Wetting On The BGA. | 16 September, 2017

An assembly with this improperly solder joints will have functional issues. We have encountered this many times with memory modules failures,RMA units. Reflow always solved the problem (in our many cases). Dwelling time may be the key to solve this. The solder balls from the BGA didn't appear to melt completely and formed smooth,new balls with the paste.

reply »

#78894

Poor Wetting On The BGA. | 18 September, 2017

Besides the good advises above, I will add my observation. Your picture shows no ball collapse on any of the balls at this end raw. Now the question is, what kind of part is that? There is a possibility that your part is warping to cause that. It wouldn't hurt to bake this part before usage and observe results.

reply »

#78897

Poor Wetting On The BGA. | 19 September, 2017

Thank You for these hints, we´ve checked whole temp. profile (including dwelling time) and we follow all of specifications to components. Anyway we are still facing approx. once per two months issue with our customer, where only one BGA ball is nonwetted. We already excluded PCB, warpage of BGA and PCB, temp. profile, stencil etc... Do You know if there is somewhere any lab. who could support this with analysis? Thank You

reply »

#78906

Poor Wetting On The BGA. | 20 September, 2017

SEM Lab, Inc. supports this type of analysis. Please see semlab.com & semlab.com/blog for examples. Thanks!

reply »

#78910

Poor Wetting On The BGA. | 21 September, 2017

Thank You! I will try to go in touch with them...

reply »

Conformal Coating Machine under 40000

Capillary Underfill process