Plasma processing apparatus

Abstract

A plasma processing apparatus includes a processing chamber, a first electrode and a second electrode disposed to face each other, a high frequency power supply unit for applying a high frequency power to either the first electrode or the second electrode, a processing gas supply unit for supplying a processing gas to a processing space, and a main dielectric member provided at a substrate mounting portion on a main surface of the first electrode. A focus ring is attached to the first electrode to cover a peripheral portion of the main surface of the first electrode and a peripheral dielectric member is provided in a peripheral portion on the main surface of the first electrode so that an electrostatic capacitance per unit area applied between the first electrode and the focus ring is smaller than that applied between the first electrode and the substrate by the main dielectric member.

1 . A plasma processing apparatus comprising:
 an evacuable processing chamber;   a first electrode for supporting a target substrate in the processing chamber;   a second electrode disposed to face the first electrode;   a first high frequency power supply unit for applying a first high frequency power having a first frequency to either the first electrode or the second electrode;   a processing gas supply unit for supplying a processing gas to a processing space formed between the first electrode and the second electrode;   a main dielectric member provided at a substrate mounting portion on a main surface of the first electrode;   a focus ring attached to the first electrode to cover a peripheral portion of the main surface of the first electrode positioned in an outer side of the substrate mounting portion; and   a peripheral dielectric member provided in the peripheral portion of the main surface of the first electrode so that an electrostatic capacitance per unit area applied between the first electrode and the focus ring is smaller than an electrostatic capacitance per unit area applied between the first electrode and the substrate by the main dielectric member.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein a first conductor is provided in the main dielectric member, and a DC voltage for generating an electrostatic attraction force to the substrate is applied to the first conductor. 
     
     
         3 . The plasma processing apparatus of  claim 2 , wherein a first thermally conductive gas supply unit for supplying a thermally conductive inert gas is provided between the main dielectric member and the substrate. 
     
     
         4 . The plasma processing apparatus of  claim 1 , wherein a second conductor is provided in the peripheral dielectric member, and a DC voltage for generating an electrostatic attraction force to the focus ring is applied to the second conductor. 
     
     
         5 . The plasma processing apparatus of  claim 4 , wherein a second thermally conductive gas supply unit for supplying a thermally conductive inert gas is provided between the peripheral dielectric member and the focus ring. 
     
     
         6 . The plasma processing apparatus of  claim 1 , wherein the peripheral dielectric member is formed in a hollow shape and has therein a fluid dielectric member of which volume is variable. 
     
     
         7 . The plasma processing apparatus of  claim 1 , wherein the peripheral dielectric member is made of a same material forming the main dielectric member. 
     
     
         8 . The plasma processing apparatus of  claim 1 , wherein the peripheral dielectric member has a thickness greater than the thickness of the main dielectric member. 
     
     
         9 . The plasma processing apparatus of  claim 1 , wherein the peripheral dielectric member is integratedly formed with the main dielectric member. 
     
     
         10 . The plasma processing apparatus of  claim 1 , wherein the focus ring comprises a first ring-shaped member provided near an outer edge of the main dielectric member and a second ring-shaped member disposed near an outer peripheral surface of the first ring-shaped member. 
     
     
         11 . The plasma processing apparatus of  claim 10 , wherein the first ring-shaped member is disposed so that a gap formed between an outer edge of the substrate supported on the main dielectric member and an inner peripheral surface of the second ring-shaped member is positioned above the first ring-shaped member. 
     
     
         12 . The plasma processing apparatus of  claim 10 , wherein a conductor for generating an electrostatic attraction force to the focus ring is provided in the peripheral dielectric member to face the second-ring shaped member. 
     
     
         13 . The plasma processing apparatus of  claim 1 , further comprising a second high frequency power supply unit for applying to the first electrode a second high frequency power having a second frequency lower than the first frequency. 
     
     
         14 . A plasma processing apparatus comprising:
 an evacuable processing chamber;   a first electrode for supporting a target substrate in the processing chamber;   a second electrode disposed to face the first electrode;   a first high frequency power supply unit for applying a first high frequency power having a first frequency to either the first electrode or the second electrode;   a processing gas supply unit for supplying a processing gas to a processing space formed between the first electrode and the second electrode;   a main dielectric member provided at a substrate mounting portion on a main surface of the first electrode;   a focus ring attached to the first electrode to cover a peripheral portion of the main surface of the first electrode positioned in an outer side of the substrate mounting portion;   a peripheral insulating member provided in a peripheral portion on the main surface of the first electrode contacted with the focus ring; and   an electrostatic capacitance varying unit for varying an electrostatic capacitance of the peripheral insulating portion.   
     
     
         15 . The plasma processing apparatus of  claim 14 , wherein the electrostatic capacitance varying unit has a variable capacitor.