SUBSTRATE INTER-TERMINAL VOLTAGE SENSING CIRCUIT

摘要

A substrate inter-terminal voltage sensing circuit which can promptly sense a plasma charge-up occurring on a semiconductor wafer across a wide range without connection of a voltage measuring instrument. The substrate inter-terminal voltage sensing circuit is adapted to sense a voltage occurring between a pair of electrodes arranged on a semiconductor substrate. The voltage sensing circuit includes a resistance path that is connected between the electrodes. The voltage sensing circuit also includes a circuit power supply that is connected at one end to a midpoint of the resistance path. The voltage sensing circuit also includes at least two fuse circuits that are connected between one end of the resistance path and the other end of the circuit power supply so as to be in parallel with each other. The fuse circuits have different rated fusing currents from each other. Each of the fuse circuits includes a switch that turns ON or OFF depending on a potential difference between the one end and midpoint of the resistance path. Each fuse circuit also has a current path that is connected across the circuit power supply. The current path possesses a resistive element and a fuse element serially connected to the switch.