Other

Renesas Electronics Corporation

Mitsuo Yasaka

Fumihiko Uesugi

Natsuko Ito

Yousuke Itagaki

Masayoshi Takeshita

In a plasma processing apparatus having an electrostatic chuck for holding a semiconductor wafer by an electrostatic adsorption force and a DC power supply for applying an electrostatic adsorption voltage to the electrostatic chuck, abnormal discharge in plasma is suppressed by providing the apparatus with a signal detector that detects a foresee signal that foresees occurrence of abnormal discharge in plasma, and a controller that controls ESC leakage current based upon the foresee signal. If the foresee signal is outside a prescribed range, control is exercised so as to reduce the absolute value of the electrostatic adsorption voltage, thereby suppressing the occurrence of an abnormal discharge.

Plasma processing apparatus and method of suppressing abnormal discharge therein

An anomalous arc discharge detection apparatus, including multiplicity of ultrasonic detectors placed at different sections of a plasma processing chamber such that an ultrasonic wave accompanying an anomalous discharge is detected by the ultrasonic detectors at different propagation times or with different delay times. The detected signals are compared with each other on the same time axis to obtain the maximum range of variation of the detected waveforms and the differences in delay time of the respective ultrasonic detectors. From the comparison of the maximum range of variation and the delay times of the ultrasonic detectors, the position of the source point, and the level as well, of the anomalous arc discharge are determined, which can be displayed on a monitor and utilized to issue an alarm if necessary. The position of the anomalous discharge may be obtained by an asymptotic approximation based on recursive calculations of the distances from the source point to the respective ultrasonic detectors using formulas which define the distances in terms of the delay times. This can be done using only four ultrasonic detectors arranged on the wall of the processing chamber. An AE sensor hold case is provided to accommodate an AE sensor. The hold sensor has a lower cover which has one end to be glued onto an appropriate position of the processing chamber, and an upper cover which pushes the AE sensor against the lower cover with an adequate pressure.

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Kumamoto, Japan

Mitsuo Yasaka