Plasma processing apparatus, electrode plate for plasma processing apparatus, and electrode plate manufacturing method

Abstract

A plasma processing apparatus for performing a plasma process on a target substrate includes a process container configured to accommodate the target substrate and to reduce pressure therein. A first electrode is disposed within the process container. A supply system is configured to supply a process gas into the process container. An electric field formation system is configured to form an RF electric field within the process container so as to generate plasma of the process gas. A number of protrusions are discretely disposed on a main surface of the first electrode and protrude toward a space where the plasma is generated.

1 . A plasma processing apparatus for performing a plasma process on a target substrate, the apparatus comprising:
 a process container configured to accommodate the target substrate and to reduce pressure therein;   a first electrode disposed within the process container;   a gas supply system configured to supply a process gas into the process container;   an electric field formation system configured to form a radio frequency (RF) electric field within the process container so as to generate plasma of the process gas; and   a dielectric body disposed on a main surface of the first electrode and having a thickness larger at an electrode central portion than at an electrode edge portion,   wherein the first electrode is provided with an outer electrode portion protruding by a required protruding amount relative to the main surface toward a space where the plasma is generated, the outer electrode portion being distant from an outer edge of the dielectric body by a required distance outward in a radial direction.   
     
     
         2 . The apparatus according to  claim 1 , wherein the outer electrode portion is covered with a dielectric protection layer. 
     
     
         3 . The apparatus according to  claim 2 , wherein the dielectric protection layer is a layer prepared by processing a surface of the outer electrode portion. 
     
     
         4 . The apparatus according to  claim 2 , wherein the dielectric protection layer is a thermal-sprayed film formed on the outer electrode portion. 
     
     
         5 . The apparatus according to  claim 4 , wherein the thermal-sprayed film consist essentially of a material selected from the group consisting of Al 2 O 3  and Y 2 O 3 . 
     
     
         6 . The apparatus according to  claim 1 , wherein the outer electrode portion and an inner electrode portion of the first electrode are connected by an inclined portion having a surface inclined outward in a radial direction. 
     
     
         7 . The apparatus according to  claim 6 , wherein the inclined portion starts from the inner electrode portion at a position outside an edge of the target substrate in a radial direction. 
     
     
         8 . The apparatus according to  claim 1 , wherein the required protruding amount is set to adjust a distribution characteristic of an intensity of the electric field to increase the intensity near an edge of the target substrate. 
     
     
         9 . The apparatus according to  claim 1 , wherein the dielectric body includes a tapered portion disposed at its periphery and having a thickness that decreases taper-wise toward the outer edge. 
     
     
         10 . The apparatus according to  claim 1 , wherein the dielectric body includes a flat portion disposed at a center to be concentric with the first electrode and having a first diameter and a first constant thickness, and a tapered portion disposed outside the first diameter to be concentric with the flat portion and having a thickness that decreases taper-wise toward the electrode edge portion. 
     
     
         11 . The apparatus according to  claim 10 , wherein the tapered portion is directly connected to the flat portion in the dielectric body. 
     
     
         12 . The apparatus according to  claim 1 , wherein the apparatus further comprises a second electrode disposed opposite to the first electrode within the process container, such that the first electrode is an upper electrode, and the second electrode is a lower electrode on which the target substrate is placed. 
     
     
         13 . The apparatus according to  claim 12 , wherein the second electrode is configured to place thereon the target substrate essentially having a circular contour. 
     
     
         14 . The apparatus according to  claim 12 , wherein the electric field formation system includes an RF power supply connected to the first electrode or the second electrode and configured to apply an RF power thereto. 
     
     
         15 . The apparatus according to  claim 1 , wherein the gas supply system is configured to supply as the process gas a gas for etching the target substrate. 
     
     
         16 . The apparatus according to  claim 14 , wherein the RF power supply is connected to the second electrode and configured to apply an RF power having a frequency of 50 MHz or more.