Plasma processing apparatus and plasma processing method

Abstract

Uniformity of plasma density distribution and process characteristics is improved by greatly improving performance and the degree of freedom for controlling the plasma density distribution. A capacitively coupled plasma processing apparatus includes a plasma density distribution controller, installed in a chamber lower room, for controlling plasma density distribution on a susceptor. The plasma density distribution controller includes a conductive plate (first conductor) which is placed under a rear surface of the susceptor at a certain position to face the susceptor and a conductive rod (second conductor) which supports the conductive plate upward and is electrically grounded. An upper end (first connecting portion) of the conductive rod is fixed to a certain portion of a bottom surface of the conductive plate, and a lower end (second connecting portion) of the conductive rod is fixed to or is in contact with a bottom wall of a chamber.

1 . A plasma processing apparatus in which a high frequency electrode is provided in a processing chamber and, when a plasma process is performed on a target object in the processing chamber, a first high frequency power is applied to a rear surface of the high frequency electrode and a surface of the high frequency electrode is exposed to plasma of a processing gas, the apparatus comprising:
 a first conductor which has first and second surfaces facing opposite directions to each other and is electrically connected with the rear surface of the high frequency electrode with respect to the first high frequency power, the first surface facing a portion of the rear surface of the high frequency electrode; and   a second conductor which includes a first connecting portion(s) electrically connected with a portion of the second surface of the first conductor and a second connecting portion electrically connected with a conductive grounding member electrically grounded around the high frequency electrode with respect to the first high frequency power.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein the first conductor is capacitively coupled to the rear surface of the high frequency electrode. 
     
     
         3 . The plasma processing apparatus of  claim 1 , wherein a high frequency power feed rod for supplying the first high frequency power to the high frequency electrode is connected with a central portion of the rear surface of the high frequency electrode, and
 the first and second conductors are distanced away from the high frequency power feed rod in a radial direction.   
     
     
         4 . The plasma processing apparatus of  claim 1 , wherein the first conductor is a conductive plate having the first and second surfaces substantially parallel to each other. 
     
     
         5 . The plasma processing apparatus of  claim 1 , wherein the second conductor includes one first connecting portion, and
 electric field intensity on the first surface of the first conductor is not uniform and becomes maximum at a position corresponding to the first connecting portion.   
     
     
         6 . The plasma processing apparatus of  claim 1 , wherein the second conductor includes a plurality of the first connecting portions, and
 electric field intensity on the first surface of the first conductor is not uniform and becomes maximum at positions each corresponding to the plurality of the first connecting portions.   
     
     
         7 . The plasma processing apparatus of  claim 6 , wherein the first conductor includes a plurality of first conductive members separated from each other, and
 the second conductor has the first connecting portions connected with each of the first conductive members.   
     
     
         8 . The plasma processing apparatus of  claim 6 , wherein the second conductor includes a plurality of second conductive members separated from each other, and
 each of the second conductive members has the first connecting portion connected with the first conductor.   
     
     
         9 . The plasma processing apparatus of  claim 6 , wherein the plurality of the first connecting portions are substantially equi-spaced in an azimuthal direction of the high frequency electrode. 
     
     
         10 . The plasma processing apparatus of  claim 1 , wherein the second conductor is a column-shaped body, and its one end serves as the first connecting portion and the other end or a middle portion between the one end and the other end serves as the second connecting portion. 
     
     
         11 . The plasma processing apparatus of  claim 1 , wherein the second conductor is a plate-shaped body or a cylinder-shaped body, and its one end surface serves as the first connecting portion and the other end surface or a middle portion between the one end surface and the other end surface serves as the second connecting portion. 
     
     
         12 . The plasma processing apparatus of  claim 1 , further comprising:
 a first conductor moving unit for varying a position of the first conductor with respect to the high frequency electrode.   
     
     
         13 . The plasma processing apparatus of  claim 12 , wherein the first conductor moving unit varies the position of the first conductor in a vertical direction with respect to the rear surface of the high frequency electrode. 
     
     
         14 . The plasma processing apparatus of  claim 12 , wherein the first conductor moving unit varies the position of the first conductor in an azimuthal direction of the high frequency electrode. 
     
     
         15 . The plasma processing apparatus of  claim 12 , wherein the first conductor moving unit varies the position of the first conductor in a radial direction of the high frequency electrode. 
     
     
         16 . The plasma processing apparatus of  claim 1 , further comprising:
 a second conductor moving unit for varying a position of the first connecting portion of the second conductor with respect to the high frequency electrode.   
     
     
         17 . The plasma processing apparatus of  claim 16 , wherein the second conductor moving unit varies the position of the first connecting portion in a vertical direction with respect to the rear surface of the high frequency electrode. 
     
     
         18 . The plasma processing apparatus of  claim 16 , wherein the second conductor moving unit varies the position of the first connecting portion in an azimuthal direction of the high frequency electrode. 
     
     
         19 . The plasma processing apparatus of  claim 18 , wherein the second conductor moving unit rotationally moves the second conductor at a constant speed in the azimuthal direction of the high frequency electrode during a plasma process. 
     
     
         20 . The plasma processing apparatus of  claim 16 , wherein the second conductor moving unit varies the position of the first connecting portion in a radial direction of the high frequency electrode. 
     
     
         21 . The plasma processing apparatus of  claim 1 , wherein a dielectric member is provided between the rear surface of the high frequency electrode and the first conductor. 
     
     
         22 . The plasma processing apparatus of  claim 1 , wherein a facing electrode is provided to face the high frequency electrode parallel to each other at a predetermined distance therebetween within the processing chamber and is electrically grounded, and
 the target object is mounted on the high frequency electrode.   
     
     
         23 . The plasma processing apparatus of  claim 1 , wherein an electrostatic chuck for holding the target object by an electrostatic attracting force is installed on the surface of the high frequency electrode,
 the electrostatic chuck has a dielectric film and a DC electrode embedded in the dielectric film, and   a high voltage line for applying a DC voltage to the DC electrode from a DC power supply is substantially insulation-coated and is connected with the DC electrode through the high frequency electrode from its rear surface.   
     
     
         24 . The plasma processing apparatus of  claim 1 , wherein a resistance heating element for controlling a temperature of the target object is mounted on the surface of the high frequency electrode via a dielectric member, and
 a power feed line for supplying a current for Joule's heat generation to the resistance heating element from a heater power supply is substantially insulation-coated and is connected with the resistance heating element through the high frequency electrode from its rear surface.   
     
     
         25 . The plasma processing apparatus of  claim 1 , wherein a second high frequency power having a frequency different from that of the first high frequency power is applied to the high frequency electrode from its rear surface during the plasma process, and
 the first conductor is electrically connected with the rear surface of the high frequency electrode and is electrically grounded via the second conductor with respect to the second high frequency power.   
     
     
         26 . The plasma processing apparatus of  claim 1 , wherein the rear surface of the high frequency electrode, the first conductor and the second conductor are placed in an atmosphere region isolated from a depressurized space of the processing chamber. 
     
     
         27 . The plasma processing apparatus of  claim 26 , wherein the first and second conductors are installed within a cylindrical insulating member extending from a bottom wall of the processing chamber to an outer peripheral portion of the high frequency electrode. 
     
     
         28 . The plasma processing apparatus of  claim 27 , wherein the processing chamber is made of conductive metal electrically grounded, and
 the second connecting portion of the second conductor is electrically connected with the bottom wall of the processing chamber.   
     
     
         29 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 1 , the method comprising:
 controlling plasma density distribution on the high frequency electrode by varying or adjusting a position of the first conductor with respect to the rear surface of the high frequency electrode.   
     
     
         30 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 1 , the method comprising:
 controlling plasma density distribution on the high frequency electrode by varying or adjusting a capacitance of a capacitor formed between the rear surface of the high frequency electrode and the first conductor.   
     
     
         31 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 1 , the method comprising:
 controlling plasma density distribution on the high frequency electrode by varying or adjusting a position of the first connecting portion of the second conductor with respect to the rear surface of the high frequency electrode.   
     
     
         32 . A plasma processing apparatus in which a facing electrode faces a high frequency electrode parallel to each other at a predetermined distance therebetween in a processing chamber and when a plasma process is performed on a target object within the processing chamber, a first high frequency power is applied to a rear surface of the high frequency electrode, and each surface of the high frequency electrode and the facing electrode is exposed to plasma of a processing gas, the apparatus comprising:
 a first conductor which has first and second surfaces facing opposite directions to each other and is electrically connected with a rear surface of the facing electrode with respect to the first high frequency power, the first surface facing a portion of the rear surface of the facing electrode; and   a second conductor which includes a first connecting portion electrically connected with a portion of the second surface of the first conductor and a second connecting portion electrically connected with a conductive member electrically grounded around the facing electrode with respect to the first high frequency power.   
     
     
         33 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 32 , the method comprising:
 controlling plasma density distribution on the facing electrode by varying or adjusting a position of the first conductor with respect to the rear surface of the facing electrode.   
     
     
         34 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 32 , the method comprising:
 controlling plasma density distribution on the facing electrode by varying or adjusting a capacitance of a capacitor formed between the rear surface of the facing electrode and the first conductor.   
     
     
         35 . A plasma processing method for performing a plasma process on a target object by using the plasma processing apparatus of  claim 32 , the method comprising:
 controlling plasma density distribution on the facing electrode by varying or adjusting a position of the first connecting portion of the second conductor with respect to the rear surface of the facing electrode.