Plasma processing apparatus and plasma processing method

Abstract

A plasma processing apparatus includes a high frequency antenna having first and second antenna elements. One end of the first antenna element is grounded and the other end thereof is connected to a high frequency power supply. One end of the second antenna element is an open end and the other end thereof is connected to either one of the one end and the other end of the first antenna element, a line length of the second antenna element having a value obtained by multiplying ((λ/4)+nλ/2) by a fractional shortening (λ is a wavelength of high frequency in vacuum and n is a natural number). A circuit viewed from the high frequency power supply toward the high frequency antenna is configured to generate, when a frequency of a high frequency power is changed, two resonant frequencies by an adjustment of the impedance adjustment unit.

What is claimed is: 
     
         1 . A plasma processing apparatus for performing a process on a substrate mounted on a mounting unit in a processing chamber of a vacuum atmosphere by exciting a processing gas supplied into the processing chamber and generating plasma, the plasma processing apparatus comprising:
 a high frequency antenna formed of a vortex coil arranged opposite to a processing target surface of the substrate mounted on the mounting unit, the high frequency antenna being connected to a high frequency power supply that is a variable frequency power supply and including a first antenna element and a second antenna element;   an impedance adjustment unit including variable-capacity capacitors for adjusting a resonant frequency of a circuit viewed from the high frequency power supply toward the high frequency antenna;   a dielectric configured to airtightly isolate a vacuum atmosphere in the processing chamber from a space in which the high frequency antenna is arranged; and   a shield member configured to surround the space in which the high frequency antenna is arranged,   wherein one end of the first antenna element is grounded and the other end thereof is connected to the high frequency power supply,   wherein one end of the second antenna element is an open end and the other end thereof is connected to either one of the one end of the first antenna element and the other end of the first antenna element, a line length of the second antenna element having a value obtained by multiplying ((λ/4)+nλ/2) by a fractional shortening, where λ is a wavelength of high frequency in vacuum and n is a natural number, and the second antenna element being set to resonate at a power frequency to be used, and   wherein the circuit viewed from the high frequency power supply toward the high frequency antenna is configured to generate, when a frequency of a high frequency power is changed, a first resonant frequency and a second resonant frequency by an adjustment of the impedance adjustment unit.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein the variable-capacity capacitors of the impedance adjustment unit include a variable-capacity capacitor provided between the high frequency power supply and the high frequency antenna and connected in series to the high frequency power supply, and a variable-capacity capacitor provided between the other end of the second antenna element and an earth. 
     
     
         3 . The plasma processing apparatus of  claim 1 , wherein the variable-capacity capacitors of the impedance adjustment unit include a variable-capacity capacitor for adjusting a reflectivity of high frequency which is connected in parallel to the high frequency power supply. 
     
     
         4 . The plasma processing apparatus of  claim 2 , wherein the variable-capacity capacitors of the impedance adjustment unit further include a variable-capacity capacitor for adjusting a reflectivity of high frequency which is connected in parallel to the high frequency power supply. 
     
     
         5 . A plasma processing method using the plasma processing apparatus of  claim 1 , the plasma processing method comprising:
 supplying, from the high frequency power supply to the high frequency antenna, a high frequency power having a frequency between the first resonant frequency and the second resonant frequency; and   performing a plasma-process on the substrate.   
     
     
         6 . A plasma processing method using the plasma processing apparatus of  claim 2 , the plasma processing method comprising:
 supplying, from the high frequency power supply to the high frequency antenna, a high frequency power having a frequency between the first resonant frequency and the second resonant frequency; and   performing a plasma-process on the substrate.