As you are aware the common method to rework BGA is : 1. Remove BGA with hot air reflow machine ( SRT as current practice) 2. Clean the BGA pad using solder iron and solder wick. 3. Replace BGA with SRT rework machine.
The problem we have with unplug via is when we clean the BGA pad, the solder resist cover the trace between pads and vias will be removed. During the solder removal process certain amount of solder will also get into the unplug vias as well. During BGA replacement process, two thing will happen. First, due to vias plug with solder, explosion might happen and cause solder short or open. Second, due to the solder resist has been removed, the solder from BGA ball will flow into the vias and cause insufficient or unsolder BGA balls.
I would like to hear any one have any process that could take care of such problem.
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