BGA soldering pads - how do you repair them?

[Jane]

Does anyone have any experience with damaged BGA  soldering pads?I mean the soldering pads on PCB.
I would guess that a thin( but how much thin ??) copper wire and a glue( but which one is the best) could help.

I desoldered CPU that has about 1000 pads and one pad was damaged( it is 1.2V core voltage).
I noticed that there are more pads with the same core voltage. Must be all 1.2V soldered or it is not so critical if one is not soldered?
Not sure if all 1.2V must be present.

[Rerouter]

in almost all cases yes all pins are required, playing with 1000 pin BGA's is already a hard task,

What i will say is however you do it, your going to keep the added thickness extremly low or you will cause the BGA to not sit as flush as it should,

The other point is making sure if surface tension tugs your fix (at high temperatures) that it wont short out on nearby pads,

[cowana]

in almost all cases yes all pins are required...

With my experience of BGAs, this isn't the case. When the core draws a high amount of power (say 10A at 1.1v for an FPGA), a lot of pins are used to keep the voltage drop low. These will internally be connected to a plane inside the BGA - so if one of them is missing, it won't cause any issues.

The device is likely to have multiple rails of the same voltage in addition to the main core supply (eg a rail for each clock, PLL, tranceiver etc), so there's no guarantee a specific pin isn't dedicated (and thus required) for one of them - but in my experience, in the majority of cases (75?%) one out of several hundred power pins could be disconnected without too much of a problem.