I'm not an expert, but my impression was that chip fabs are incredibly sterile places. You could probably disable one for a long time by just chucking a barrel full of dust into the cleanroom.

If it were total destruction, my money would be on artillery. Wikipedia says the range for modern artillery is 15-300km, which gives a very wide radius in which artillery could be hidden (ignoring local geography). If the artillery was preemptively dialed into the fab, it could be fired at very short notice, and I don't think anyone would be able to stop the shells mid-flight.