Sputtering system and method including an arc detection
A sputtering system that includes a sputtering chamber having a target material serving as a cathode, and an anode and a work piece. A direct current (DC) power supply supplies electrical power to the anode and the cathode sufficient to generate a plasma within the sputtering chamber. A detection module detects the occurrence of an arc in the sputtering chamber by monitoring an electrical characteristic of the plasma. In one embodiment the electrical characteristic monitored is the impedance of the plasma. In another embodiment the electrical characteristic is the conductance of the plasma.
1. A method for controlling a plasma system, the method comprising:
supplying direct current (DC) power to an anode of a process chamber and to a cathode of the process chamber sufficient to generate a plasma within said process chamber; and
detecting an occurrence of an arc in said process chamber by monitoring at least one of an impedance and a conductance of said plasma during a plasma operation being performed within said process chamber, wherein the detecting further comprises further comprises one of:
multiplying a sensed current signal by a pre-selected resistance value to generate a voltage trip signal, and comparing a sensed voltage signal to the voltage trip signal and if the sensed voltage signal is less than the voltage trip signal, generating a voltage trip indicator signal; or
multiplying the sensed voltage signal by a pre-selected conductance value to generate a current trip signal, and comparing the sensed current signal to the current trip signal and if the sensed current signal is greater than the current trip signal, generating a current trip indicator signal.
2. A method for controlling a system, the method comprising:
supplying direct current (DC) power to an anode of a process chamber and to a cathode of the process chamber sufficient to generate a plasma within the process chamber; and
detecting an occurrence of an arc in the process chamber by monitoring at least one of an impedance and a conductance of the plasma during a plasma operation being performed within the process chamber including:
receiving a sensed voltage signal or a sensed current signal indicating a respective voltage or current applied to the process chamber via the anode and the cathode;
multiplying one of the sensed current signal or sensed voltage signal by a respective pre-selected resistance value or pre-selected conductance value to generate one of a respective voltage trip signal or current trip signal; and
comparing the one of the sensed voltage signal or the sensed current signal to the respective voltage trip signal or the current trip signal and if the sensed voltage signal is less than the voltage trip signal, generating a voltage trip indicator signal, or if the sensed current signal is greater than the current trip signal, generating a current trip indicator signal.
3. The method of claim 2 , wherein detecting the occurrence of an arc in the process chamber by monitoring at least one of an impedance and a conductance of the plasma further comprises monitoring the conductance of the plasma, and wherein the monitoring further comprises monitoring a current flowing between the anode of the process chamber and the cathode of the process chamber and generating the sensed current signal therefrom.
4. The method of claim 2 , wherein detecting the occurrence of an arc in the process chamber by monitoring at least one of an impedance and a conductance of the plasma further comprises monitoring the impedance of the plasma, and wherein the monitoring further comprises monitoring a voltage across the cathode and the anode and generating the sensed voltage signal therefrom.
5. The method of claim 3 , further comprising simultaneously monitoring the voltage across the cathode and the anode while a sputtering operation is occurring within the process chamber.
6. The method of claim 4 , further comprising simultaneously monitoring the current across the cathode and the anode while a sputtering operation is occurring within the process chamber.