Plasma processing apparatus
A plasma processing apparatus includes a balun having a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, and a second balanced terminal, a grounded vacuum container, a first electrode electrically connected to the first balanced terminal, a second electrode electrically connected to the second balanced terminal, an impedance matching circuit, a first power supply connected to the balun via the impedance matching circuit, and configured to supply a high frequency to the first electrode via the impedance matching circuit and the balun, a low-pass filter, and a second power supply configured to supply a voltage to the first electrode via the low-pass filter.
1. A plasma processing apparatus comprising:
a balun including a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, and a second balanced terminal;
a grounded vacuum container formed by a conductor;
a first electrode electrically connected to the first balanced terminal;
a second electrode electrically connected to the second balanced terminal;
an impedance matching circuit;
a first power supply connected to the balun via the impedance matching circuit, and configured to supply a high frequency to the first electrode via the impedance matching circuit and the balun;
a low-pass filter; and
a second power supply configured to supply a voltage to the first electrode via the low-pass filter;
wherein the balun includes a first coil configured to connect the first unbalanced terminal and the first balanced terminal, and a second coil configured to connect the second unbalanced terminal and the second balanced terminal.
2. The plasma processing apparatus according to claim 1 , wherein the first electrode holds a target, and the second electrode holds a substrate.
3. The plasma processing apparatus according to claim 1 , wherein the balun further includes a third coil and a fourth coil both of which are connected between the first balanced terminal and the second balanced terminal, and the third coil and the fourth coil are configured to set, as a midpoint between a voltage of the first balanced terminal and a voltage of the second balanced terminal, a voltage of a connection node of the third coil and the fourth coil.
4. The plasma processing apparatus according to claim 3 , wherein the connection node is connected to the vacuum container.
5. The plasma processing apparatus according to claim 1 wherein
the second power supply includes an AC power supply, and
a frequency of a voltage supplied from the AC power supply to the first electrode is lower than the frequency.
6. The plasma processing apparatus according to claim 1 wherein the first electrode is supported by the vacuum container via an insulator.
7. The plasma processing apparatus according to claim 1 , wherein an insulator is arranged between the second electrode and the vacuum container.
8. The plasma processing apparatus according to claim 1 , further comprising at least one of a mechanism configured to vertically move the second electrode and a mechanism configured to rotate the second electrode.
9. The plasma processing apparatus according to claim 1 , wherein the first electrode holds a substrate, and the plasma processing apparatus is configured as an etching apparatus.
10. The plasma processing apparatus according to claim 1 , wherein the first electrode holds a target, and the second electrode is arranged around the first electrode.
11. The plasma processing apparatus according to claim 1 , wherein
a plurality of high-frequency supply units are provided, and each of the plurality of high-frequency supply units includes the balun, the first electrode, and the second electrode, and
the first electrode of each of the plurality of high-frequency supply units holds a target and, in each of the plurality of high-frequency supply units, the second electrode is arranged around the first electrode.
12. The plasma processing apparatus according to claim 10 , wherein the first electrode and the second electrode are supported by the vacuum container via an insulator.
13. The plasma processing apparatus according to claim 10 , further comprising:
a third electrode configured to hold a substrate; and
a second high-frequency power supply configured to supply a high frequency to the third electrode via a second impedance matching circuit.
14. The plasma processing apparatus according to claim 13 , further comprising:
a second DC power supply configured to supply a DC voltage to the third electrode via a second low-pass filter.
15. The plasma processing apparatus according to claim 13 , wherein an insulator is arranged between the third electrode and the vacuum container.
16. The plasma processing apparatus according to claim 13 , further comprising at least one of a mechanism configured to vertically move the third electrode and a mechanism configured to rotate the third electrode.
17. The plasma processing apparatus according to claim 1 , wherein the first balanced terminal and the first electrode are electrically connected via a blocking capacitor.
18. The plasma processing apparatus according to claim 1 , wherein the second balanced terminal and the second electrode are electrically connected via a blocking capacitor.
19. The plasma processing apparatus according to claim 1 , wherein when Rp represents a resistance component between the first balanced terminal and the second balanced terminal when viewing a side of the first electrode and the second electrode from a side of the first balanced terminal and the second balanced terminal, and X represents an inductance between the first unbalanced terminal and the first balanced terminal, 1.5≤X/Rp≤5000 is satisfied.
20. The plasma processing apparatus according to claim 1 , wherein a part of a current flowing through the first coil flows to ground through the grounded vacuum container.