Chestnut - ningu terminus method of detection null of plasma chemical vapor phase accumulation

摘要

PURPOSE:To detect the cleaning end point within a deposition chamber by obtaining an output from a wattmeter which measures a reflection power for discharge input power or from a voltmeter which measures a DC bias voltage of discharge electrode and outputting a signal when a voltage reaches the selectively preset value. CONSTITUTION:After starting glow discharge by into reducing etching into the deposition chamber to which deposited film is adhered, inductance and capacitance of matching circuit 3 are adjusted so that the power indicated by a reflection power meter 4 is minimized. Thereafter, when a thin film adhered to the deposition chamber is removed, a reflection power is increased and the cleaning end point can be monitored by detecting that a reflection power reaches a preset value with an end point detector 5. When a thin film adhered to the deposition chamber, change of DC bias voltage of discharge power can be measured with a bias voltmeter 8, it is detected by the end point detector 5 that the DC bias voltage has reached a preset value and thereby the cleaning end point can be monitored.