Microwave plasma processing apparatus

Abstract

In a microwave plasma processing apparatus, when a surface of a planar antenna 31 for radiating a microwave to form a plasma is concentrically divided into a central region 31 a, an outer circumferential region 31 c and a middle region 31 b therebetween, a plurality of pairs of microwave radiating holes 32 elongated in different directions are concentrically arranged in the central region 31 a and the outer circumferential region 31 c and no microwave radiating hole is formed in the middle region 31 b, and a microwave radiating surface of a microwave transmitting plate 28 is provided with a concave portion 28 a.

1 - 14 . (canceled) 
     
     
         15 . A microwave plasma processing apparatus for forming a plasma of a process gas by a microwave and executing a plasma process to a workpiece by the plasma, comprising:
 a chamber in which the workpiece is housed;   a placing table for placing the workpiece in the chamber;   a microwave generating source for generating a microwave;   a waveguide for guiding the microwave generated from the microwave generating source toward the chamber;   a planar antenna made of a conductive material for radiating the microwave guided by the waveguide toward the chamber;   a microwave transmitting plate made of a dielectric material, the microwave transmitting plate defining a top wall of the chamber and transmitting the microwave that has passed through microwave radiating holes of the planar antenna; and   a process gas introducing unit for introducing the process gas into the chamber via a pipe;   wherein when a surface of the planar antenna is concentrically divided into a central region, an outer circumferential region and a middle region therebetween, a plurality of the microwave radiating holes are formed in the central region and the outer circumferential region and no microwave radiating hole is formed in the middle region;   wherein a plurality of pairs of the microwave radiating holes are concentrically arranged in the central region and the outer circumferential region, the pair of the microwave radiating holes comprising a first microwave transmitting hole formed in an inner side and a second microwave radiating hole formed in an outer side, and the first and the second transmitting holes being disposed in different directions from each other; and   wherein a concave portion is formed in a lower surface of the microwave transmitting plate; the concave portion has an arch-type cross-section; a portion of the concave portion corresponding to the workpiece is flat; and at least a portion of the first microwave radiating hole of the pair of the microwave radiating holes formed in the outer circumferential region is arranged so as to be engaged with the concave portion.   
     
     
         16 . The microwave plasma processing apparatus of  claim 15 , wherein the pair of the microwave radiating holes is formed such that ends in longitudinal directions of the first microwave radiating hole and the second microwave radiating hole are close to each other and the other ends are spaced from each other. 
     
     
         17 . The microwave plasma processing apparatus of  claim 16 , wherein an angle formed between the longitudinal directions of the first microwave radiating hole and the second microwave radiating hole ranges from 80° to 100°. 
     
     
         18 . The microwave plasma processing apparatus of  claim 15 , wherein a length along the longitudinal direction of the microwave radiating hole formed in the central region is shorter than a length along the longitudinal direction of the microwave radiating hole formed in the outer circumferential region. 
     
     
         19 . The microwave plasma processing apparatus of  claim 15 , wherein the concave portion is formed to be larger than a diameter of the workpiece. 
     
     
         20 . The microwave plasma processing apparatus of  claim 15 , wherein a lower surface of the microwave transmitting plate has annular projections in its periphery projected downwardly. 
     
     
         21 . A microwave plasma processing apparatus for forming a plasma of a process gas by a microwave and executing a plasma process to a workpiece by the plasma, comprising:
 a chamber in which the workpiece is housed;   a placing table for placing the workpiece in the chamber;   a microwave generating source for generating a microwave;   a waveguide for guiding the microwave generated from the microwave generating source toward the chamber;   a planar antenna made of a conductive material for radiating the microwave guided by the waveguide toward the chamber;   a microwave transmitting plate made of a dielectric material, the microwave transmitting plate defining a top wall of the chamber and transmitting the microwave that has passed through microwave radiating holes of the planar antenna; and   a process gas introducing unit for introducing the process gas into the chamber via pipes;   wherein when a surface of the planar antenna is concentrically divided into a central region, an outer circumferential region and a middle region therebetween, a plurality of the microwave radiating holes are formed in the central region and the outer circumferential region and no microwave radiating hole is formed in the middle region;   wherein a plurality of pairs of the microwave radiating holes are concentrically arranged in the central region and the outer circumferential region, the pair of the microwave radiating holes comprising a first microwave radiating hole formed in an inner side and a second microwave radiating hole formed in an outer side, and the first and the second microwave radiating holes being disposed in different directions from each other; and   wherein a lower surface of the microwave transmitting plate is formed in a concavo-convex shape.   
     
     
         22 . The microwave plasma processing apparatus of  claim 21 , wherein the pair of the microwave radiating holes is formed such that ends in longitudinal directions of the first microwave radiating hole and the second microwave radiating hole are close to each other and the other ends are spaced from each other. 
     
     
         23 . The microwave plasma processing apparatus of  claim 22 , wherein an angle formed between the longitudinal directions of the first microwave radiating hole and the second microwave radiating hole ranges from 80° to 100°. 
     
     
         24 . The microwave plasma processing apparatus of  claim 21 , wherein a length along the longitudinal direction of the microwave radiating hole formed in the central region is shorter than a length along the longitudinal direction of the microwave radiating hole formed in the outer circumferential region. 
     
     
         25 . The microwave plasma processing apparatus of  claim 21 , wherein a lower surface of the microwave transmitting plate has convex portions and concave portions concentrically arranged by turns. 
     
     
         26 . The microwave plasma processing apparatus of  claim 21 , wherein a lower surface of the microwave transmitting plate has annular projections in its periphery projected downwardly. 
     
     
         27 . The microwave plasma processing apparatus of  claim 15 , wherein a height of a portion of the microwave transmitting plate corresponding to the concave portion ranges from 10 to 30 mm. 
     
     
         28 . The microwave plasma processing apparatus of  claim 15 , wherein a height of the concave portion ranges from 15 to 25 mm. 
     
     
         29 . The microwave plasma processing apparatus of  claim 15 , wherein when a distance between a center point of the first microwave radiating hole in the central region and a center of the planar antenna is set as “1,” a distance between a center point of the first microwave radiating hole in the outer region and the center of the planar antenna ranges from 2 to 4. 
     
     
         30 . A microwave plasma processing apparatus for forming a plasma of a process gas by a microwave and executing a plasma process to a workpiece by the plasma, comprising:
 a chamber in which the workpiece is housed;   a placing table for placing the workpiece in the chamber;   a microwave generating source for generating a microwave;   a waveguide for guiding the microwave generated from the microwave generating source toward the chamber;   a planar antenna made of a conductive material for radiating the microwave guided by the waveguide toward the chamber;   a microwave transmitting plate made of a dielectric material, the microwave transmitting plate defining a top wall of the chamber and transmitting the microwave that has passed through microwave radiating holes of the planar antenna; and   a process gas introducing unit for introducing the process gas into the chamber via pipes,   wherein when a surface of the planar antenna is concentrically divided into a central region, an outer circumferential region and a middle region therebetween, a plurality of the microwave radiating holes are formed in the central region and the outer circumferential region and no microwave radiating hole is formed in the middle region;   wherein a plurality of pairs of the microwave radiating holes are concentrically arranged in the central region and the outer circumferential region, the pair of the microwave radiating holes comprising a first microwave radiating hole formed in an inner side and a second microwave radiating hole formed in an outer side, and the first and the second microwave radiating holes being disposed in different directions from each other;   wherein when a distance between a center point of the first microwave radiating hole in the central region and a center of the planar antenna is set as “1,” a distance between a center point of the first microwave radiating hole in the outer region and the center of the planar antenna ranges from 2 to 4; and   wherein a lower surface of the microwave transmitting plate has a concave portion having an arch-type cross-section and a portion of the concave portion corresponding to the workpiece is flat.