Removing botom glue from BGA..How ?

[tomodachi]

Some Haswell / Broadwell chips has some strong glue under them which is not allowing BGA to remove safely without damaging connection pads. Have anyone managed to remove this kind of chip without damaging BGA connections ? I m trying to figure out if they can be reballed or not, but first I need to remove it in one piece. There are some cheap glue remover chemicals on aliexpress but they only softening outer glue, not helping with my case, see pics.
I think I need a dissolver but my searches so far brought me nothing.
Thanks.
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[jasko_jacker]

Re: Removing botom glue from BGA..How ?

in these cases the temperature management is very important, in the third picture there are the balls that did not reach the liquefaction temperature.
The pads also were ripped in areas where the glue is not present.
The areas where the glue is detached, don't show signs of damage on the layer surface .
The problem is to understand the correct temperatures in which to remove the BGA and in which all the alloy is in a liquid state.
it is however preferable to increase the temperature. it's better to damage the BGA that the layer of the board.
There are chemicals that help but if the glue is near the center fail to act