JP2004509429A5 - - Google Patents

Description

[Claims]
1. A plasma reactor for use with a supply of RF power to process a workpiece, the plasma reactor comprising:
A vacuum chamber having a ceiling and defining axial symmetry;
A workpiece support pedestal in the chamber;
A first solenoidal interleaved coil antenna having a first plurality of conductors disposed on at least an intermediate portion of the ceiling and wound around an axis of symmetry in a respective coaxial helical solenoid;
With
The plurality of conductors are at least substantially uniformly laterally displaced from the axis of symmetry, the plurality of conductors are offset from one another in a direction of the substantially symmetry axis, and each of the plurality of conductors is at opposite ends of an RF source power supply. A plasma reactor characterized by being connected.
2. The coil antenna is located between an upper surface and a lower surface substantially perpendicular to the axis of symmetry, and a helical solenoid defined by each conductor includes an upper point of the conductor near the upper surface and a conductor near the lower surface. The reactor of claim 1, wherein the RF power supply is terminated at a lower point of the conductor and the RF power supply is connected to both ends of the upper and lower points of each of the conductors.
3. An apparatus according to claim 2, wherein said upper point is connected to an output terminal of said RF power supply, and said lower point is grounded so as to reduce a potential near said ceiling. Plasma reactor.
4. The plasma of claim 2, wherein said upper points are angularly displaced from each other by about 360 / n, where n is the number of said plurality of conductors of the coil antenna. Reactor.
5. The plasma of claim 4, wherein the lower points are angularly displaced from each other by about 360 / n, where n is the number of the plurality of conductors of the coil antenna. Reactor.
6. The plasma reactor according to claim 5, wherein said upper point is on the same plane and is on said upper surface.
7. The plasma reactor according to claim 6, wherein said lower point is on the same plane and is on said lower surface.
8. The apparatus further comprises an inner coil antenna located on the ceiling, surrounded by the first solenoidal interleaved conductor coil antenna, and having a smaller lateral extent, The plasma reactor according to claim 1, wherein the interleaved conductor coil antenna of the first solenoid is an outer coil antenna.
9. The apparatus further comprises a second RF plasma source power supply connected to said inner coil antenna, such that respective RF power levels supplied to said inner and outer antennas are respectively equal to said inner and outer antennas. 9. The plasma reactor of claim 8, wherein the reactor is differentially adjustable to control a radial distribution of an RF magnetic field supplied from the antenna.
10. The first RF plasma source power supply has two RF outputs having differentially adjustable power levels, one of the two RF outputs being connected to the outer antenna; The other is connected to the inner antenna, so that the respective RF power levels supplied to the inner and outer antennas are used to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas. 9. The plasma reactor according to claim 8, wherein the reactor is differentially adjustable.
11. The number of said first plurality of conductors is greater than the number of said second plurality of conductors, and the length of said first plurality of conductors accordingly sets the inductive reactance of said outer antenna to said inductive reactance. 9. The plasma reactor according to claim 8, wherein the plasma reactor is shortened so as to at least approach an inductive reactance of the inner antenna.
12. The inner antenna is positioned about the axis of symmetry of a coaxial helical solenoid positioned on the ceiling and at least substantially uniformly laterally displaced from the axis of symmetry less than the displacement of the outer antenna. A second solenoid interleaved conductor coil antenna having a second plurality of conductors wound thereon, wherein each helical solenoid conductor is offset from another helical solenoid conductor in a direction parallel to said axis of symmetry. The plasma reactor according to claim 8, wherein:
13. The plasma reactor according to claim 12, wherein the number of said first plurality of conductors of said outer antenna is larger than the number of said second plurality of conductors of said inner antenna.
14. An RF plasma source power supply having two RF outputs having differentially adjustable power levels, one of said two RF outputs being connected to said outer antenna, and the other being connected to said outer antenna. The respective RF power levels connected to the inner antenna and thereby supplied to the inner and outer antennas are operatively adjustable to control the radial distribution of the RF magnetic field supplied from the inner and outer antennas The plasma reactor according to claim 13, wherein:
15. The RF plasma source power supply comprises:
An RF power generator having an output terminal and a return terminal;
A series capacitor;
An impedance matching element connected between an output terminal of the RF power generator and one side of the series capacitor;
A variable parallel capacitor connected between the other side of the series capacitor and the return terminal;
A first output node connected to a connection point between the impedance matching element and the series capacitor;
A second output node connected to a connection point between the series capacitor and the variable parallel capacitor;
The plasma reactor according to claim 14, comprising: