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BGA Rework (Top side heat only!)

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#73580

BGA Rework (Top side heat only!) | 24 February, 2015

I was handed the task to develop a process to solder a BGA using topside heat only. It is a long story so I will spare the details, but I was wondering if anyone has ever attempted this? I have been going at it for a few weeks with fair results, but the process window seems very tight. Also, what is a good test to verify good solder connection on the BGA? Is there a simple one?

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#73607

BGA Rework (Top side heat only!) | 26 February, 2015

The best test will be to X-ray BGA under 3-D X-ray. About the techniques used for BGA repair you can probably take closer look to some BGA repair stations, even though I have seen it done with hot air gun in the early days.

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#73746

BGA Rework (Top side heat only!) | 27 March, 2015

That is a strange task. I must ask what is the purpose? When performing BGA Rework the goal is to recreate the manufacturing process of using the reflow oven. It is important to have even heat of the BGA and PCB from top to bottom. Using top heat only is harsh on the BGA Chip, does not guarantee that your PCB is heated enough to create a good bond, and induces board warping.

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#73748

BGA Rework (Top side heat only!) | 28 March, 2015

I would agree with the comments so far its much better to have some pre heat. You have not explained why bottom side preheat is a problem. Even having some input will help balance the process. Assume there is some thing on the back side that is a problem?

Using top side only you tend to run too hot or too long to reflow most BGAs and the surface temperature on the top to the bottom may run with a much larger dT.

Even in the early days with BGA when we had rework systems which were little better than paint strippers we still placed double sided boards in an oven to raise the core PCB temperature.

Bob Willis bob@bobwillis.co.uk

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#73754

BGA Rework (Top side heat only!) | 30 March, 2015

The PCB is in a housing when it is returned from the field and it takes 1.5 hours to remove the PCB from the housing so we are looking for a way to rework the BGA without removing it from the housing. Hence, top-side rework only.

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#74834

BGA Rework (Top side heat only!) | 5 November, 2015

It's a strange task . if your PCB is very very small ,using topside heat is not a big problem . but for a whole PCB board . if delete the step of preheat, it will broke the whole PCB . BTW,do you finish your task ?

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