Plasma processing apparatus

Abstract

A plasma processing apparatus includes a plasma generation unit for converting a processing gas into plasma by an inductive coupling. The plasma generation unit includes a first high frequency antenna formed of a vortex coil having open opposite endse and, at a central portion of a line between the open ends, a supply point of a high frequency power and a grounding point grounded through a capacitor; a second high frequency antenna formed of a planar vortex coil disposed between first and second high frequency antenna elements of the first high frequency antenna; and an impedance adjustment unit for adjusting a resonant frequency of a circuit viewed from a high frequency power supply toward the first high frequency antenna which is configured to have two resonant frequencies depending on adjustment of the impedance adjustment unit when the frequency of the high frequency power is changed.

What is claimed is: 
     
         1 . A plasma processing apparatus for performing a plasma process on a substrate in a processing chamber, the apparatus comprising:
 a mounting table on which the substrate is mounted, the mounting table being provided in the processing chamber;   a processing gas supply unit configured to supply a processing gas into the processing chamber;   an exhaust unit configured to vacuum-exhaust an inside of the processing chamber;   a plasma generation unit arranged opposite to the mounting table through a dielectric window, the plasma generation unit including a high frequency antenna for converting the processing gas supplied into the processing chamber into plasma by an inductive coupling; and   a shield member that surrounds a space where the high frequency antenna is arranged,   wherein the plasma generation unit includes:
 a first high frequency antenna formed of a vortex coil having open ends at an inner side and an outer side, and including, at a central portion of a line between the open ends, a supply point of a high frequency power supplied from a high frequency power supply and a grounding point grounded through a capacitor, the first high frequency antenna having a resonant frequency corresponding to a frequency of the high frequency power, the first high frequency antenna further including a first high frequency antenna element formed of a portion of the vortex coil from one open end at the inner side or the outer side to the supply point of the high frequency power and a second high frequency antenna element formed of a portion of the vortex coil from the other open end to the grounding point; 
 a second high frequency antenna formed of a planar vortex coil disposed between the first high frequency antenna element and the second high frequency antenna element when the first high frequency antenna is viewed from above; and 
 an impedance adjustment unit including a variable capacitor connected to both ends of the second high frequency antenna and a capacitor connected to the second high frequency antenna element, the impedance adjustment unit being configured to adjust a resonant frequency of a circuit viewed from the high frequency power supply toward the first high frequency antenna, 
 wherein the circuit viewed from the high frequency power supply toward the first high frequency antenna is configured to have a first resonant frequency and a second resonant frequency depending on adjustment of the impedance adjustment unit when the frequency of the high frequency power is changed. 
   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein each of the first high frequency antenna element and the second high frequency antenna element has a line length of ((λ/4)+(nλ/2)) multiplied by a fractional shortening, where λ is a wavelength of a high frequency and n is a natural number. 
     
     
         3 . The plasma processing apparatus of  claim 1 , wherein the impedance adjustment unit includes a variable capacitor group. 
     
     
         4 . The plasma processing apparatus of  claim 2 , wherein the impedance adjustment unit includes a variable capacitor group. 
     
     
         5 . The plasma processing apparatus of  claim 1 , wherein the second high frequency antenna is arranged at a same height position as the first high frequency antenna. 
     
     
         6 . The plasma processing apparatus of  claim 2 , wherein the second high frequency antenna is arranged at a same height position as the first high frequency antenna. 
     
     
         7 . The plasma processing apparatus of  claim 3 , wherein the second high frequency antenna is arranged at a same height position as the first high frequency antenna. 
     
     
         8 . The plasma processing apparatus of  claim 4 , wherein the second high frequency antenna is arranged at a same height position as the first high frequency antenna. 
     
     
         9 . The plasma processing apparatus of  claim 1 , wherein the second high frequency antenna is arranged at a different height position from the first high frequency antenna. 
     
     
         10 . The plasma processing apparatus of  claim 2 , wherein the second high frequency antenna is arranged at a different height position from the first high frequency antenna. 
     
     
         11 . The plasma processing apparatus of  claim 3 , wherein the second high frequency antenna is arranged at a different height position from the first high frequency antenna. 
     
     
         12 . The plasma processing apparatus of  claim 4 , wherein the second high frequency antenna is arranged at a different height position from the first high frequency antenna.