Plasma processing apparatus

Abstract

A plasma processing apparatus that generates a uniform plasma, thus allowing uniform processing of large-diameter wafers. The cylindrical apparatus includes a wafer mounting table, a silica plate providing an airtight seal, a microwave supplier for propagating a microwave in TE11-mode, and a cylindrical waveguide connected at one end to the microwave supplier. A radial waveguide box is connected between the other end of the cylindrical waveguide and the silica plate. The radial waveguide box extends radially outward from the cylindrical waveguide, forming a flange and defining an interior waveguide space. A disc-shaped slot antenna is located at the lower end of the radial waveguide box, above the silica plate. A circularly-polarized wave converter disposed in the cylindrical waveguide rotates the TE11-mode microwave about the axis of the cylindrical waveguide, and sends the rotating microwave to the radial waveguide box.

1 - 14 . (canceled)  
   
   
       15 . A plasma processing apparatus comprising: 
 a processing container shaped to be a cylinder with a bottom, the processing container having, inside thereof, a mounting table for mounting an object to be processed thereon;    a lid body made of a dielectric material to cover an upper opening of the processing container;    a microwave supplier for supplying a microwave;    a cylindrical waveguide having one end connected to the microwave supplier, the cylindrical waveguide being formed so as to extend from the microwave supplier toward the lid body thereby defining a waveguide space in the cylindrical waveguide;    a radial waveguide box connected to the other end of the cylindrical waveguide and also formed so as to extend from the other end of the cylindrical waveguide radially outward in form of a flange and successively extend downward therefrom in form of a sidewall, the radial waveguide box defining another waveguide space therein; and    a slot antenna arranged along the lid body to cover a lower opening of the radial waveguide box. the slot antenna having a plurality of slots formed therein,    wherein a periphery between the slot antenna and the processing container has an absorbing member arranged to absorb a high frequency wave.    
   
   
       16 . A plasma processing apparatus as claimed in  claim 15 , wherein the slot antenna is held by struts each made of a dielectric material.  
   
   
       17 . A plasma processing apparatus as claimed in  claim 15 , wherein an interior of the radial waveguide box is filled up with a dielectric material.  
   
   
       18 . A plasma processing apparatus as claimed in  claim 15 , wherein an outer periphery inside the radial waveguide box has an absorbing member arranged to absorb a high frequency wave.  
   
   
       19 . A plasma processing apparatus comprising: 
 a processing container shaped to be a cylinder with a bottom, the processing container having, inside thereof, a mounting table for mounting an object to be processed thereon;    a lid body made of a dielectric material to cover an upper opening of the processing container;    a microwave supplier for supplying a microwave;    a cylindrical waveguide having one end connected to the microwave supplier, the cylindrical waveguide being formed so as to extend from the microwave supplier toward the lid body thereby defining a waveguide space in the cylindrical waveguide;    a radial waveguide box connected to the other end of the cylindrical waveguide and also formed so as to extend from the other end of the cylindrical waveguide radially outward in form of a flange and successively extend downward therefrom in form of a sidewall, the radial waveguide box defining another waveguide space therein; a slot antenna arranged alone the lid body to cover a lower opening of the radial waveguide box, the slot antenna having a Plurality of slots formed therein; and    a circularly-polarized wave converter arranged in the cylindrical waveguide between the microwave supplier and the radial waveguide box to rotate the microwave in TE11 mode about an axis of the cylindrical waveguide thereby transmitting a resulting circularly-polarized wave to the radial waveguide box,    wherein the microwave to be propagated from the microwave supplier to the radial waveguide box through the cylindrical waveguide box is identical to a microwave in TE11 mode, and    wherein the apparatus further comprises, between the microwave supplier and the cylindrical waveguide: 
 a rectangular waveguide extending from the microwave supplier;  
 a circular-and-rectangular converter arranged between the rectangular waveguide and the cylindrical waveguide; and  
 a cylindrical dummy load having its one end connected to the cylindrical waveguide between the circular-and-rectangular converter and the circularly-polarized wave converter, the other end of the cylindrical dummy load having a microwave absorber.  
   
   
   
       20 . A plasma processing apparatus as claimed in  claim 19 , wherein the dummy load is provided, at its connecting part with the cylindrical waveguide, with a partition wall which separates an interior of the cylindrical waveguide and an interior of the dummy load and has a slit formed to be parallel with an axial direction of the cylindrical waveguide.  
   
   
       21 . A plasma processing apparatus as claimed in  claim 19 , further comprising a rod-shaped reflector arranged in the waveguide between the cylindrical waveguide and the circular-and-rectangular converter, the rod-shaped reflector consisting of a conductor bridged in a direction substantially perpendicular to an axis of the cylindrical waveguide and substantially perpendicular to an extending direction of the dummy load.  
   
   
       22 . A plasma processing apparatus as claimed in  claim 21 , wherein the reflector is a plate body along a plane containing the axis of the cylindrical waveguide.  
   
   
       23 . A plasma processing apparatus as claimed in  claim 19 , wherein an axis of the dummy load is arranged in a position apart from the reflector toward the circularly-polarized wave converter by a quarter of guide wavelength of a standing wave reflected by the reflector.  
   
   
       24 . A plasma processing apparatus comprising: 
 a processing container shaped to be a cylinder with a bottom. the processing container having, inside thereof, a mounting table for mounting an object to be processed thereon;    a lid body made of a dielectric material to cover an upper opening of the processing container:    a microwave supplier for supplying a microwave;    a cylindrical waveguide having one end connected to the microwave supplier, the cylindrical waveguide being formed so as to extend from the microwave supplier toward the lid body thereby defining a waveguide space in the cylindrical waveguide;    a radial waveguide box connected to the other end of the cylindrical waveguide and also formed so as to extend from the other end of the cylindrical waveguide radially outward in form of a flange and successively extend downward therefrom in form of a sidewall, the radial waveguide box defining another waveguide space therein;    a slot antenna arranged along the lid body to cover a lower opening of the radial waveguide box, the slot antenna having a plurality of slots formed therein;    a circularly-polarized wave converter arranged in the cylindrical waveguide between the microwave supplier and the radial waveguide box to rotate the microwave in TE11 mode about an axis of the cylindrical waveguide thereby transmitting a resulting circularly-polarized wave to the radial waveguide box; and    a tuner arranged in the cylindrical waveguide between the circularly-polarized wave converter and the radial waveguide box to adjust an impedance in the cylindrical waveguide thereby to reflect a microwave, which has been returned by reflection of the radial waveguide box, toward the radial waveguide box,    wherein the microwave to be propagated from the microwave supplier to the radial waveguide box through the cylindrical waveguide box is identical to a microwave in TE11 mode.    
   
   
       25 . A plasma processing apparatus as claimed in  claim 24 , wherein the tuner comprises: 
 a plurality of stubs projecting from an inner circumferential wall of the cylindrical waveguide inwardly in a radial direction thereof, with respective adjustable projecting amounts;    a stub driver for driving the stubs in the radial direction;    a detector arranged inside the cylindrical waveguide between the stubs and the circularly-polarized converter to detect an intensity of electromagnetic field of a microwave in the cylindrical waveguide; and    a controller for driving the stub driver on a basis of the intensity of electromagnetic field of the microwave detected by the detector thereby to change respective positions of the stubs in the radial direction for adjustment of an impedance, the controller for controlling the microwave, which has been returned from the part of the radial waveguide box, so as to reflect toward the radial waveguide box.    
   
   
       26 . A plasma processing apparatus as claimed in  claim 25 , wherein the stubs are complete in twelve stubs which are arranged on an inner circumferential face of the cylindrical waveguide and which consist of four stubs arranged at regular intervals in a circumferential direction of the cylindrical waveguide for each level and also lined three deep along an axial direction of the cylindrical waveguide.  
   
   
       27 . A plasma processing method for a plasma processing apparatus including: a processing container accommodating an object to be processed therein and having an upper opening covered by a lid body made of a dielectric material; a microwave supplier for supplying a microwave; a cylindrical waveguide having one end connected to the microwave supplier, the cylindrical waveguide being formed so as to extend from the microwave supplier toward the lid body thereby defining a waveguide space in the cylindrical waveguide; a radial waveguide box connected to the other end of the cylindrical waveguide and also formed so as to extend from the other end of the cylindrical waveguide radially outward and successively extend downward therefrom in form of a sidewall, the radial waveguide box defining another waveguide space therein; a slot antenna adapted so as to cover a lower opening of the radial waveguide box; and a circularly-polarized wave converter for rotating a microwave in TE11 mode supplied from the microwave supplier about an axis of the cylindrical waveguide thereby transmitting the microwave as a circularly-polarized wave to the radial waveguide box; the plasma processing method comprising the steps of: 
 rotating the microwave in TE11 mode supplied from the microwave supplier about the axis of the cylindrical waveguide thereby transmitting the microwave as the circularly-polarized wave to the radial waveguide box;    monitoring a microwave which has been reflected by the part of the radial waveguide box and subsequently returned therefrom;    tuning the so-reflected microwave on a basis of a result at the monitoring step; and    producing a uniform plasma in the processing container by the tuning step.