Plasma treatment apparatus and plasma treatment method

Abstract

According to one embodiment, there is provided a plasma treatment apparatus including an electrode, a first power supply circuit, a plasma generating unit, a second power supply circuit, a sensing unit, and a control unit. The electrode is arranged inside a treatment chamber. On the electrode, a substrate to be treated is placed. The first power supply circuit supplies power to the electrode. The plasma generating unit generates plasma in a space separated from the electrode inside the treatment chamber. The second power supply circuit supplies power to the plasma generating unit. The sensing unit senses a parameter output from the first power supply circuit. The control unit controls power supplied from the second power supply circuit so that the parameter sensed by the sensing unit becomes close to or substantially equal to a target value.

1 . A plasma treatment apparatus comprising:
 an electrode which is arranged inside a treatment chamber and on which a substrate to be treated is placed;   a first power supply circuit which supplies power to the electrode;   a plasma generating unit which generates plasma in a space separated from the electrode inside the treatment chamber;   a second power supply circuit which supplies power to the plasma generating unit;   a sensing unit which senses a parameter output from the first power supply circuit; and   a control unit which controls power supplied from the second power supply circuit so that the parameter sensed by the sensing unit becomes close to or substantially equal to a target value.   
     
     
         2 . The plasma treatment apparatus according to  claim 1 ,
 wherein the parameter sensed by the sensing unit includes a voltage.   
     
     
         3 . The plasma treatment apparatus according to  claim 2 ,
 wherein the control unit increases power supplied from the second power supply circuit when the voltage sensed by the sensing unit is higher than the target value and decreases power supplied from the second power supply circuit when the voltage sensed by the sensing unit is lower than the target value.   
     
     
         4 . The plasma treatment apparatus according to  claim 1 ,
 wherein the parameter sensed by the sensing unit includes a current.   
     
     
         5 . The plasma treatment apparatus according to  claim 4 ,
 wherein the control unit decreases power supplied from the second power supply circuit when the current sensed by the sensing unit is greater than the target value and increases power supplied from the second power supply circuit when the current sensed by the sensing unit is smaller than the target value.   
     
     
         6 . The plasma treatment apparatus according to  claim 1 ,
 wherein the first power supply circuit includes   a generating unit which generates power,   a second sensing unit which senses power generated by the generating unit, and   a second control unit which controls power generated by the generating unit in accordance with the sensing result of the second sensing unit,   a control operation of the control unit and a control operation of the second control unit being performed in parallel in a mutually independent form.   
     
     
         7 . A plasma treatment method in a plasma treatment apparatus that includes an electrode, a first power supply circuit, a plasma generating unit, and a second power supply circuit, the electrode being arranged inside a treatment chamber and on the electrode a substrate to be treated being placed, the first power supply circuit supplying power to the electrode, the plasma generating unit generating plasma in a space separated from the electrode inside the treatment chamber, the second power supply circuit supplying power to the plasma generating unit, the plasma treatment method comprising:
 sensing a parameter output from the first power supply circuit; and   controlling power supplied from the second power supply circuit so that the sensed parameter becomes close to or substantially equal to a target value.   
     
     
         8 . The plasma treatment method according to  claim 7 ,
 wherein, in the sensing of the parameter, a voltage output from the first power supply circuit is sensed, and   in the controlling of power, when the sensed voltage is higher than the target value, power supplied from the second power supply circuit increases, and when the sensed voltage is lower than the target value, power supplied from the second power supply circuit decreases.   
     
     
         9 . The plasma treatment method according to  claim 7 ,
 wherein, in the sensing of the parameter, a current output from the first power supply circuit is sensed, and   in the controlling of power, when the sensed current is greater than the target value, power supplied from the second power supply circuit decreases, and when the sensed current is smaller than the target value, power supplied from the second power supply circuit increases.   
     
     
         10 . A plasma treatment apparatus comprising:
 an electrode which is arranged inside a treatment chamber and on which a substrate to be treated is placed;   a power supply circuit which supplies power to the electrode;   a plasma generating unit which generates plasma in a space separated from the electrode inside the treatment chamber; and   a detecting unit which detects a bias voltage that is a difference between a potential of the plasma generated by the plasma generating unit and a potential of the electrode to which power is supplied from the power supply circuit,   wherein the power supply circuit includes   a main unit which generates power to be supplied to the electrode, and   a correcting unit which corrects a capacitance value of the power supply circuit so that the bias voltage detected by the detecting unit becomes close to or substantially equal to a target value.   
     
     
         11 . The plasma treatment apparatus according to  claim 10 ,
 wherein the detecting unit includes   a first detection terminal which extends to the space separated from the electrode inside the treatment chamber, and   a second detection terminal which is electrically connected to the electrode, and   wherein the detecting unit obtains a difference between a voltage detected by the first detection terminal and a voltage detected by the second detection terminal to detect the bias voltage.   
     
     
         12 . The plasma treatment apparatus according to  claim 10 ,
 wherein the correcting unit includes   a first variable-capacitance element which is connected in series with the main unit with respect to the electrode,   a second variable-capacitance element which is connected in parallel with the main unit with respect to the electrode, and   a changing unit which changes at least one of a capacitance value of the first variable-capacitance element and a capacitance value of the second variable-capacitance element so that the bias voltage detected by the detecting unit becomes close to or substantially equal to the target value.   
     
     
         13 . The plasma treatment apparatus according to  claim 12 ,
 wherein the changing unit performs at least an operation to increase the capacitance value of the second variable-capacitance element when the bias voltage detected by the detecting unit is higher than the target value and performs at least an operation to increase the capacitance value of the first variable-capacitance element when the bias voltage detected by the detecting unit is lower than the target value.   
     
     
         14 . The plasma treatment apparatus according to  claim 10 ,
 wherein the correcting unit includes   a storage unit which stores a plurality of different target values, and   a determining unit which determines a target value corresponding to a processing condition of plasma treatment from among the plurality of different target values stored in the storage unit,   the capacitance value of the power supply circuit being corrected so that the bias voltage detected by the detecting unit becomes close to or substantially equal to the target value determined by the determining unit.   
     
     
         15 . The plasma treatment apparatus according to  claim 10 ,
 wherein the correcting unit includes   a storage unit which stores a plurality of different target values, and   a determining unit which determines a target value corresponding to an elapsed time of plasma treatment from among the plurality of different target values stored in the storage unit,   the capacitance value of the power supply circuit being corrected so that the bias voltage detected by the detecting unit becomes close to or substantially equal to the target value determined by the determining unit.   
     
     
         16 . The plasma treatment apparatus according to  claim 10 , further comprising:
 a storage unit which stores correlation information regarding a correlation between the bias voltage and a processing shift amount; and   a controller which predicts the processing shift amount on the basis of the bias voltage detected by the detecting unit and the correlation information stored in the storage unit, and adjusts a processing condition so that the processing shift amount falls within a range of a threshold value.   
     
     
         17 . A plasma treatment method in a plasma treatment apparatus that includes an electrode and a power supply circuit, the electrode being arranged inside a treatment chamber, and on the electrode a substrate to be treated being placed, the power supply circuit supplying power to the electrode, the plasma treatment method comprising:
 supplying power from the power supply circuit to the electrode and generating plasma in a space separated from the electrode inside the treatment chamber;   detecting a bias voltage that is a difference between the potential of the generated plasma and the potential of the electrode to which power is supplied;   correcting a capacitance value of the power supply circuit so that the detected bias voltage becomes close to or substantially equal to a target value; and   processing the substrate to be treated using the plasma treatment apparatus after the correcting is performed.   
     
     
         18 . The plasma treatment method according to  claim 17 ,
 wherein the power supply circuit includes   a main unit which generates power to be supplied to the electrode, and   a correcting unit which compensates for a capacitance value of the main unit to correct the capacitance value of the power supply circuit so that the detected bias voltage becomes close to or substantially equal to the target value,   wherein the correcting unit includes   a first variable-capacitance element which is connected in series with the main unit with respect to the electrode, and   a second variable-capacitance element which is connected in parallel with the main unit with respect to the electrode, and   wherein, in the correcting of the capacitance value of the power supply circuit, at least one of a capacitance value of the first variable-capacitance element and a capacitance value of the second variable-capacitance element is changed so that the detected bias voltage becomes close to or substantially equal to the target value.   
     
     
         19 . The plasma treatment method according to  claim 17 , further comprising:
 determining a target value corresponding to a processing condition of plasma treatment from among a plurality of different target values, and comparing the detected bias voltage with the determined target value before the correcting of the capacitance value of the power supply circuit,   wherein the capacitance value of the power supply circuit is corrected in accordance with the comparison result so that the detected bias voltage becomes close to or substantially equal to the determined target value.   
     
     
         20 . The plasma treatment method according to  claim 17 , further comprising:
 determining a target value corresponding to an elapsed time of plasma treatment from among a plurality of different target values, and comparing the detected bias voltage with the determined target value before the correcting of the capacitance value of the power supply circuit,   wherein the capacitance value of the power supply circuit is corrected in accordance with the comparison result so that the detected bias voltage becomes close to or substantially equal to the determined target value.