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BGA epoxy removal

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#73564

BGA epoxy removal | 22 February, 2015

Hi, my name is Dacian, and i run a mobile phone repair shop in Timisoara, Romania. Lately we decided to do more advance motherboard repair jobs, and a big problem that we have is, cleaning the board after we remove the chips. We repair manly iPhone, iPad and Samsung boards, and all of them have some kind of epoxy under the bigger BGA chips. The Apple ones have a black, type epoxy that when heated becomes kinda less hard but, almost every time we try to clean the space where the new chip will be mounted we damage some pads. Currently we are heating the spot to 200+ C and scraping with a sharp tweezer, this is very time consuming and many times the pads get damaged. On the Samsung ones the epoxy is a clear type that is not so rigid, but also it is very hard to get off the boards.

I have been searching the web for a solution for this, but did not find anything. Maybe some more skilled forum members have a solution, or at least a better way of doing this than we are doing now.

Thank you.

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#73599

BGA epoxy removal | 26 February, 2015

anyone?

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#73604

BGA epoxy removal | 26 February, 2015

Take a look at articles that explain underfill process and how to remove/rework underfill:

http://www.finetechusa.com/rework/applications/underfill-rework.html

http://www.circuitnet.com/experts/86535.shtml

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#73609

BGA epoxy removal | 26 February, 2015

Use the appropriate heat for that part. You can then use techspray flux remover with a brush. Spray the brush, and not the board, to reduce spreading the flux. Acetone or alcohol are less expensive and may work as well.

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#73737

BGA epoxy removal | 24 March, 2015

Here's some notes from IPC APEX 2015:

* Black underfill is Heraeus. It needs to be preheated to 180-200*C for rework. Above 200*C it changes state and becomes difficult.

* Clear underfill is from an unknown Korean supplier.

* People from Heraeus were impressed with the underfill removal technique used by Metcal.

* Media air blasting removes underfill.

* MG Chemicals makes a gel soldmask remover that might remove underfill. It may be difficult to clean

* AirVac recommends a scavenger product

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#73738

BGA epoxy removal | 25 March, 2015

Hi davef, thank you for sharing this. Yes all manufacturers recommend their products, and i dont deny that they are good but for a small shop like i have i think the prices are a bit high. What i think would be a good technique, is heating the area to ~190 C and then using a very fine and gentle metal brush to remove the underfill layer by layer. The problem with this mechanical methods is that because of the small package and small pitch its very easy to remove pads.

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