In one embodiment, the ESD device uses highly doped P and N regions deep within the ESD device to form a zener diode that has a controlled breakdown voltage. The control can modify a process recipe or a process sequence of the processing apparatus based on a feed forward or a feed back signal from the metrology unit. The capacitor is coupled across the signal amplifier, the inverter is coupled to the output of the signal amplifier, and the current mirror is coupled to the input of the signal amplifier.