Before revision: In particular, reactive-ion etching of the first metal layer can result in exactly the situation shown - then metal on each net is disconnected from the initial global metal layer, and the plasma etching is still adding charges to each piece of metal.
After revision: In particular, reactive-ion etching of the first metal layer can result in exactly the situation shown - the metal on each net is disconnected from the initial global metal layer, and the plasma etching is still adding charges to each piece of metal.