Patent Number: 
Section: claims

1. A plasma processing method, comprising the steps of:mounting a sample on a sample electrode disposed in a vacuum container, exhausting the vacuum container while supplying a source gas to inside the vacuum container, and generating plasma in the vacuum container by supplying high-frequency power to a plasma source; andapplying plasma to a surface of the sample while being adjusted so that thickness of an ion sheath is made uniform on the surface of the sample, in a state that a conductor ring is disposed so as to surround an outer perimeter of the sample. 2. The plasma processing method according to claim 1, wherein the plasma is adjusted so as to amorphyze a surface layer of the sample. 3. The plasma processing method according to claim 1, wherein the plasma is adjusted so as to introduce an impurity into a surface layer of the sample. 4. The plasma processing method according to claim 1, wherein the conductor ring has a surface that is approximately the same in height as the surface of the sample. 5. The plasma processing method according to claim 4, wherein a distance between the outer perimeter of the sample and an inner perimeter of the conductor ring is in a range of 1 mm to 10 mm. 6. The plasma processing method according to claim 4, wherein a difference in height between the surface of the sample and a surface of the conductor ring is in a range of 0.001 mm to 1 mm. 7. The plasma processing method according to claim 4, wherein a voltage is applied to a pedestal in a state that the sample electrode has a layered structure in which a first dielectric layer, an electrostatic chuck electrode, a second dielectric layer, and the pedestal are arranged in this order from the side that is closer to the sample, that the first dielectric layer, the electrostatic chuck electrode, and the second dielectric layer project from the pedestal, and that a third dielectric layer is disposed between the conductor ring and the pedestal. 8. The plasma processing method according to claim 7, wherein Ca=1/(d1/∈1 +d2/∈2) is larger than or equal to 0.5 times Cb=∈3/d3 and smaller than or equal to 2 times Cb, where ∈1 and d1 are relative permittivity and thickness of the first dielectric layer, ∈2 and d2 are relative permittivity and thickness of the second dielectric layer, and ∈3 and d3 are relative permittivity and thickness of the third dielectric layer. 9. The plasma processing method according to claim 4, wherein a voltage is applied to an electrostatic chuck electrode in a state that the sample electrode has a layered structure in which a first dielectric layer, the electrostatic chuck electrode, a second dielectric layer, and a pedestal are arranged in this order from the side that is closer to the sample, that the first dielectric layer, the electrostatic chuck electrode, and the second dielectric layer project from the pedestal, and that a third dielectric layer is disposed between the conductor ring and the pedestal. 10. The plasma processing method according to claim 9, wherein Cc=∈1/d1 is larger than or equal to 0.5 times Cd=1/{(d2×S2)/(∈2×S1)+d3/∈3} and smaller than or equal to 2 times Cd, where ∈l and dl are relative permittivity and thickness of the first dielectric layer, ∈2 and d2 are relative permittivity and thickness of the second dielectric layer, ∈3 and d3 are relative permittivity and thickness of the third dielectric layer, S1 is an area of a surface, exposed to the plasma, of the sample, and S2 is an area of a surface, exposed to the plasma, of the conductor ring. 11. A plasma processing method, comprising the steps of:mounting a sample on a sample electrode disposed in a vacuum container, exhausting the vacuum container while supplying a source gas to inside the vacuum container, and generating plasma in the vacuum container by supplying high-frequency power to a plasma source; andperforming plasma processing while being adjusted so that thickness of an ion sheath is made uniform on the surface of the sample, in a state that a focus ring having a surface that is higher than the surface of the sample by 1 mm or more is disposed outside an outer perimeter of the sample. 12. The plasma processing method according to claim 11, wherein a distance between the outer perimeter of the sample and an inner perimeter of the focus ring is in a range of 1 mm to 10 mm. 13. The plasma processing method according to claim 11, wherein a difference in height between the surface of the sample and a surface of the focus ring is in a range of 1 mm to 15 mm. 14. A plasma processing method, comprising the steps of:mounting a sample on a tray disposed in a vacuum container and having a step inside which the sample is mounted, exhausting the vacuum container while supplying a source gas to inside the vacuum container, and generating plasma in the vacuum container by supplying high-frequency power to a plasma source; andapplying plasma to the surface of the sample while making an adjustment so that a surface of a portion outside the recess of the tray is approximately the same in height as the surface of the sample, and being adjusted so that thickness of an ion sheath is made uniform on the surface of the sample. 15. The plasma processing method according to claim 14, wherein a distance between the outer perimeter of the sample and the step is in a range of 1 mm to 10 mm. 16. The plasma processing method according to claim 14, wherein a difference in height between the surface of the sample and a surface of the portion, outside the step, of the tray is in a range of 0.001 mm to 1 mm. 17. The plasma processing method according to claim 14, wherein the sample is a silicon wafer and the tray is made of silicon. 18. The plasma processing method according to claim 14, wherein the plasma processing is performed in a state that the tray is pressed against the sample electrode. 19. The plasma processing method according to claim 14, wherein:a step of generating plasma and a step of suspending the plasma generation are performed alternately and repeatedly; andpressure in the vacuum container is set higher in the step of suspending the plasma generation than in the step of generating plasma. 20. The plasma processing method according to. claim 19, wherein a difference between the pressure in the vacuum container in the step of suspending the plasma generation and that in the step of generating plasma is in a range of 100 Pa to 1,000 Pa. 21. A plasma processing apparatus comprising:a vacuum container;a sample electrode disposed in the vacuum container and to be mounted with a sample;a gas supply apparatus for supplying a gas to inside the vacuum container;an exhaust apparatus for exhausting the vacuum container;a pressure control device for controlling pressure in the vacuum container;a plasma source;a high-frequency power source for supplying high-frequency power to the plasma source;a voltage source for applying a voltage to the sample electrode; andan auxiliary member disposed around the sample electrode so that plasma is applied to a surface of a sample while being adjusted so as to have a uniform energy state on the surface of the sample. 22. The plasma processing apparatus according to claim 21, wherein the plasma is adjusted so as to amorphyze a surface layer of the sample. 23. The plasma processing apparatus according to claim 21, wherein the plasma is adjusted so as to introduce an impurity into a surface layer of the sample. 24. The plasma processing apparatus according to claim 21, wherein:the sample electrode has a projecting portion to be mounted with the sample; andthe auxiliary member is a conductor ring disposed so as to surround an outer perimeter of the sample and to have a surface that is approximately the same in height as the surface of the sample. 25. The plasma processing apparatus according to claim 24, wherein a distance between the outer perimeter of the sample and an inner perimeter of the conductor ring is in a range of 2 mm to 11 mm. 26. The plasma processing apparatus according to claim 24, wherein a difference in height between the surface of the sample and a surface of the conductor ring is in a range of 0.001 mm to 2 mm. 27. The plasma processing apparatus according to claim 21, wherein the sample electrode has a layered structure in which a first dielectric layer, an electrostatic chuck electrode, a second dielectric layer, and a pedestal are arranged in this order from the side that is closer to the sample, the first dielectric layer, the electrostatic chuck electrode, and the second dielectric layer project from the pedestal, and a third dielectric layer is disposed between the conductor ring and the pedestal; and wherein a voltage is applied to the pedestal. 28. The plasma processing apparatus according to claim 27, wherein Ca=1/(d1/∈1 +d2/∈2) is larger than or equal to 0.5 times Cb=∈3/d3 and smaller than or equal to 2 times Cb, where ∈1 and d1 are relative permittivity and thickness of the first dielectric layer, ∈2 and d2 are relative permittivity and thickness of the second dielectric layer, and ∈3 and d3 are relative permittivity and thickness of the third dielectric layer. 29. The plasma processing apparatus according to claim 21, wherein the sample electrode has a layered structure in which a first dielectric layer, an electrostatic chuck electrode, a second dielectric layer, and a pedestal are arranged in this order from the side that is closer to the sample, the first dielectric layer, the electrostatic chuck electrode, and the second dielectric layer project from the pedestal, and a third dielectric layer is disposed between the conductor ring and the pedestal; and wherein a voltage is applied to the electrostatic chuck electrode. 30. The plasma processing apparatus according to claim 29, wherein Cc=∈1/d1 is larger than or equal to 0.5 times Cd=1/{(d2×S2)/(∈2×S1) +d3/∈3} and smaller than or equal to 2 times Cd, where ∈1 and d1 are relative permittivity and thickness of the first dielectric layer, ∈2 and d2 are relative permittivity and thickness of the second dielectric layer, ∈3 and d3 are relative permittivity and thickness of the third dielectric layer, S1 is an area of a surface, exposed to the plasma, of the sample, and S2 is an area of a surface, exposed to the plasma, of the conductor ring. 31. The plasma processing apparatus according to claim 21, wherein:the sample electrode has a projecting portion to be mounted with the sample; andthe auxiliary member is a focus ring disposed so as to surround the sample and to have a surface that is higher than the surface of the sample being mounted on the sample electrode by 1 mm or more. 32. The plasma processing apparatus according to claim 31, wherein a distance between the outer perimeter of the sample and an inner perimeter of the focus ring is in a range of 2 mm to 11 mm. 33. The plasma processing apparatus according to claim 30, wherein a difference in height between the surface of the sample and a surface of the focus ring is in a range of 2 mm to 16 mm.