| 摘要 |
<p>PURPOSE: A method and apparatus for detecting an arc in a plasma chamber are provided to prevent pollution in an object due to the arc by reducing radio frequency power. CONSTITUTION: An apparatus for detecting an arc in a plasma chamber comprises a voltage sensor (20), a current sensor (20), a circuit (24), a controller (26), a detecting unit, a comparator (28), and a logic circuit (25). The voltage sensor (20) detects a voltage value of radio frequency power being supplied to a plasma chamber. A current sensor (22) detects a current value of radio frequency power. The circuit calculates a voltage-current ratio based on the voltage and current values from the current sensor. The controller determines whether or not an arc is generated in the plasma chamber based on the voltage-current ratio. The detecting unit detects reflected power of the radio frequency power being supplied to the plasma chamber. The comparator compares the reflected power with a standard value. The logic circuit calculates a low voltage ratio outputted from the circuit, and provides the low voltage ratio to the controller. [Reference numerals] (20) Voltage sensor; (22) Current sensor; (24) Circuit for detecting a voltage and current ratio; (26) Controller; (27) Circuit for detecting reflected electricity; (30) Impedance matching unit</p> |
