Plasma processing apparatus

Abstract

To make it possible to suppress deterioration of processing properties of a sample to be processed due to the distortion of ion sheath at the end portion of the sample to be processed or possible to maintain the condition for suppressing the deterioration, so that the acquisition rate of acceptable products can be increased, so as to thereby improve the yield. In a plasma processing apparatus, a minute hole 10 is provided in a focus ring 9 in the vicinity of the inner circumferential portion thereof. Current detecting means 11 is arranged in the bottom portion of the minute hole 10. A high-frequency power is supplied to the focus ring 9 via high-frequency power distributing means 16. A state of distortion of an ion sheath 18 is detected from an amount of current which is changed according to the amount of the high-frequency power supplied to the focus ring 9 and which is detected by current detecting means 11. Further, the amount of high-frequency power supplied to the focus ring 9 is controlled by a control section 21 so as to correct the detected distortion state.

1 . A plasma processing apparatus in which process gases are converted into plasma in a vacuum chamber having vacuum evacuation means, and in which surface treatment of a sample to be processed housed in the vacuum chamber is performed by the plasma, the plasma processing apparatus comprising:
 means for mounting the sample to be processed;   means for applying a high-frequency voltage to the sample to be processed;   an annular conductor member arranged at the periphery of the sample to be processed and arranged concentrically to the sample to be processed;   means for applying a high-frequency voltage to the annular conductor member; and   current detecting means for detecting current flowing therein through a minute hole provided in a portion of the annular conductor member, which portion is close to the sample to be processed.   
   
   
       2 . The plasma processing apparatus according to  claim 1 ,
 wherein a plurality of the minute holes are arranged at positions in the periphery of the sample to be processed, and have a plurality of the current detecting means, respectively.   
   
   
       3 . A plasma processing apparatus in which process gases are converted into plasma in a vacuum chamber having vacuum evacuation means, and in which surface treatment of a sample to be processed housed in the vacuum chamber is performed by the plasma, the plasma processing apparatus comprising:
 means for mounting the sample to be processed;   means for applying a high-frequency voltage to the sample to be processed;   an annular conductor member arranged at the periphery of the sample to be processed, and arranged concentrically to the sample to be processed;   means for applying a high-frequency voltage to the annular conductor member;   current detecting means for detecting current flowing therein through a minute hole provided in a portion of the annular conductor member, which portion is close to the sample to be processed; and   a control section for controlling the high-frequency voltage applied to the annular conductor member according to a detection result in the current detecting means.   
   
   
       4 . The plasma processing apparatus according to  claim 3 ,
 wherein the control section controls the high-frequency voltage applied to the annular conductor member so that the amount of current detected by the current detecting means is always set close to a maximum value.   
   
   
       5 . The plasma processing apparatus according to  claim 3 ,
 wherein a plurality of the current detecting means are provided, and wherein the control section controls the high-frequency voltage applied to the annular conductor member by statistically determining the amount of current detected by the plurality of current detecting means.   
   
   
       6 . The plasma processing apparatus according to one of  claim 1  and  claim 3 ,
 wherein the center position of the minute hole provided in the annular member is positioned 10 mm or less away from the end portion of the sample to be processed at the time when the sample to be processed is mounted.   
   
   
       7 . The plasma processing apparatus according to one of  claim 1  and  claim 3 ,
 wherein the minute hole provided in the annular member has a hole diameter of 0.1 mm or more to 2 mm or less, and has a depth of 1 mm or more to 20 mm or less, which depth corresponds to a distance from the surface of the minute hole to the current detecting means, and wherein an aspect ratio of the depth to the hole diameter is set to 5 to 50.   
   
   
       8 . The plasma processing apparatus according to  claim 3 ,
 wherein the high-frequency voltage applied to the annular conductor member is branched and supplied via a variable capacitor from an output of the high-frequency power supply supplied to the sample to be processed, and wherein the high-frequency voltage applied to annular conductor member is controlled by changing the capacitance of the capacitor.