Plasma processing apparatus

1. A plasma processing apparatus having a chamber in which a pressure is reduced by an exhaust system and which is used for applying a plasma processing to a substrate to be processed held by a second electrode in a process gas atmosphere between a first electrode and the second electrode provided so as to be opposed to each other in parallel by using a plasma generated by high-frequency power,

wherein the first electrode comprising:

a conductive support which is held in the chamber by interposing an insulator and has a process gas introduction/diffusion function and a high-frequency power introduction function;

an electrode plate of a flat plate formed by a conductor or a semiconductor joined to a surface of the support opposed to the second electrode; and

a cavity portion formed at the center of a surface of the support joined to the electrode plate, the cavity portion having a uniform thickness.

2. The plasma processing apparatus according to claim 1, wherein a skin depth δ represented by the following expression (1) is larger than a thickness of the electrode plate:

description="In-line Formulae" end="lead"δ=(2ρ/ωμ)1/2  (1) description="In-line Formulae" end="tail"

wherein ω: an angular frequency of high-frequency power (=2πf (f: frequency)), ρ: a resistivity of the electrode plate, and μ: a magnetic permeability of the electrode plate.

3. The plasma processing apparatus according to claim 2, wherein a resistivity of the electrode plate is not less than 0.1 Ω·m.

4. The plasma processing apparatus according to claim 3, wherein a resistivity of the electrode plate is 0.3 to 0.8 Ω·m.

5. The plasma processing apparatus according to claim 1, wherein the electrode plate forms a discoid tabular shape and has an opposed surface having an area exceeding a processing surface of the substrate to be processed.

6. The plasma processing apparatus according to claim 1, wherein high-frequency power to the first electrode is a frequency within a range of 27 to 150 MHz, and supplied from the center of a surface of the support which is not opposed to the second electrode.

7. The plasma processing apparatus according to claim 1, wherein a thickness of the cavity portion is uniform, and falls within a range of 0.3 to 0.5 mm.

8. The plasma processing apparatus according to claim 1, wherein a diameter of the cavity portion is 50 mm or more.

9. The plasma processing apparatus according to claim 1, wherein, a dimension of the cavity portion being determined in such a manner that a resonance is generated at a frequency of high-frequency power to be supplied and an electric field orthogonal to the electrode plate is produced.

10. A plasma processing apparatus having a chamber in which a pressure is reduced by an exhaust system and which is used for applying a plasma processing to a substrate to be processed held by a second electrode in a process gas atmosphere between a first electrode and the second electrode provided so as to be opposed to each other in parallel by using a plasma generated by high-frequency power,

wherein the first electrode comprising:

a conductive support which is held in the chamber by interposing an insulator and has a process gas introduction/diffusion function and a high-frequency power introduction function;

an electrode plate of a flat plate formed by a conductor or a semiconductor joined to a surface of the support opposed to the second electrode; and

a cavity portion formed at the center of a surface of the electrode plate joined to the support, the cavity portion having a uniform thickness.

11. A plasma processing apparatus having a chamber in which a pressure is reduced by an exhaust system and which is used for applying a plasma processing to a substrate to be processed held by a second electrode in a process gas atmosphere between a first electrode and the second electrode provided so as to be opposed to each other in parallel by using a plasma generated by high-frequency power,

wherein the first electrode comprising:

a conductive support which is held in the chamber by interposing an insulator and has a process gas introduction/diffusion function and a high-frequency power introduction function;

an electrode plate of a flat plate formed by a conductor or a semiconductor joined to a surface of the support opposed to the second electrode; and

a cavity portion formed at the center of a surface of the support joined to the electrode plate,

wherein a skin depth δ represented by the following expression (1) is larger than a thickness of the electrode plate:

description="In-line Formulae" end="lead"δ=(2ρ/ωμ)1/2  (1) description="In-line Formulae" end="tail"

wherein ω: an angular frequency of high-frequency power (=2πf (f: frequency)), ρ: a resistivity of the electrode plate, and μ: a magnetic permeability of the electrode plate.

12. The plasma processing apparatus according to claim 11, wherein a resistivity of the electrode plate is not less than 0.1 Ω·m.

13. The plasma processing apparatus according to claim 12, wherein a resistivity of the electrode plate is 0.3 to 0.8 Ω·m.