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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

BGA inspection in mass production

Views: 3435


BGA inspection in mass production | 22 November, 2013


I aa QE on SMT line that produce products for Home introduction. No so long ago we have a problem with soldering of BGA Head on Pillow (root cause mismatching customer requirements and BGA profile spec, suplier change %Ag) and our product affect customer assembly line.

Main concern now how i should detect this types of defect on SMT/based which standard.

PS test coverage very weak, X-Ray and Scan Microscope very expensive

Thank you in advance

reply »


BGA inspection in mass production | 22 November, 2013

Head and Pillow defects beneath a BGA are difficult to find, no matter what the equipment is on hand.

Since you do not appear to have access to tools that would help you, or $$ to purchase said tools, I might recommend that you use an outside source to verify your profile and resulting solder conditions. You may be able to lock into a good profile, and if you have enough control over the rest of your processes, be able to go forward with that. I would think that your incoming inspection had better be very good, and should be able to assure that what PWBs go to the floor are actually good ones. Inspect PWB at Receiving, take the time to establish a temperature profile "window" and your location within it, and then periodically verify with another trip to your outside vendor. Make sure your oven is verified and performing correctly and consistently or this all goes out the door! Best of luck to you. 'hege

reply »


BGA inspection in mass production | 23 November, 2013


I would check the thing in the following order.

1. Check paste - SPI is the best way. If you don't get the right deposit there is no wonder you have issues. 2. Check reflow profile - tweak it to the point of perfection for the board you have. 3. Examine the part. Do you handle it right? Is it MS? I would bake it and try again. If it doesn't help order from different manufacturer and try again.

reply »


BGA inspection in mass production | 25 November, 2013

Thank you for advice, But main concern how to detect the problems with BGA on SMT line, and how I can validate "good" or "bad" profile.

PS: SPC said that process Cpk 2, temperature profile in the upper spec limit for TAL and peak temperature.

reply »


BGA inspection in mass production | 25 November, 2013

Without the proper tools in house you will not be able to determine anything but the most obvious problems.

At minimum, some side looking microscope that would allow visual inspection of a row or two, and to be able to rule out bridging. Using that scope, look for consistent sphere shape, texture, and evidence that all have collapsed evenly.

Look at the solder joints and other adjacent parts. How does the solder look? If it looks pretty good, then your BGA solder might be good too.

But remember the old wisdom... if the solder joint looks bad it probably is bad. If a solder joint looks good, then it MIGHT be good.

You really need better tools or a good friend or partner with the right EQ to nail this. Then you'll need to verify that your processes remain static as well. That too takes equipment and procedures too.

Best of luck - 'hege

reply »

x-ray inspection system

fluid dispensing robots - techcon