System for tunable workpiece biasing in a plasma reactor
Systems and methods for tunable workpiece biasing in a plasma reactor are provided herein. In some embodiments, a system includes: a plasma chamber that performs plasma processing on a workpiece, a first pulsed voltage source, coupled directly to a workpiece, a second pulsed voltage source, coupled capacitively to the workpiece, and a biasing controller comprising one or more processors, and memory, wherein the memory comprises a set of computer instructions that when executed by the one or more processors, independently controls the first pulsed voltage source and the second pulsed voltage source based on one or more parameters of the first pulsed voltage source and the second pulsed voltage source in order to tailor ion energy distribution of the flux of ions directed to the workpiece.
1. A method for tunable workpiece biasing in a plasma chamber comprising:
generating a first high voltage by a first pulsed voltage source using DC voltages and coupling the first high voltage to a workpiece in the plasma chamber via at least one direct connection, the at least one direct connection enabling ion energy control in the workpiece near the at least one direct connection;
generating one or more of low and medium voltages by a second pulsed voltage source;
coupling, capacitively, the one or more of low and medium voltages to the workpiece; and
pulsing the first high voltage and the one or more of low and medium voltages by a biasing controller, the biasing controller adjusting the first and second pulsed voltage sources in combination to achieve a configurable ion energy distribution in the workpiece.
2. The method of claim 1 , further comprising:
pulsing the first pulsed voltage source at a first frequency of approximately 100 Hz to approximately 100,000 Hz.
3. The method of claim 1 , further comprising:
pulsing the first pulsed voltage source with a duty cycle of approximately 5% to approximately 95%.
4. The method of claim 1 , further comprising:
pulsing the first pulsed voltage source at a first voltage for at least one or more duty cycles and at a second voltage for at least one or more duty cycles.
5. The method of claim 1 , further comprising:
generating a second high voltage by a third pulsed voltage source using DC voltages and coupling the second high voltage to the workpiece in the plasma chamber.
6. The method of claim 5 , further comprising:
coupling the first high voltage to at least one pin in an electrostatic chuck supporting the workpiece, the at least one pin directly coupled to the workpiece; and
coupling the second high voltage to at least one other pin in the electrostatic chuck, the at least one other pin directly coupled to the workpiece.
7. The method of claim 1 , further comprising:
adjusting the second pulsed voltage source using a voltage ramp to provide an ion energy distribution ranging from a first ion energy to a second ion energy, wherein the second ion energy is greater than the first ion energy.
8. The method of claim 7 , further comprising:
generating the first ion energy with an energy of approximately 10 eV; and
generating the second ion energy with an energy of approximately 3000 eV.
9. The method of claim 1 , further comprising:
pulsing the second pulsed voltage source a frequency of approximately 400 kHz.
10. The method of claim 1 , further comprising:
adjusting one or more voltage parameters with the biasing controller to modify a waveform emitted by the second pulsed voltage source, based on voltages sensed at the workpiece.
11. The method of claim 1 , further comprising:
pulsing the first pulsed voltage source with the biasing controller at a voltage from approximately 1 kV to approximately 10 kV during a first pulse.
12. The method of claim 1 , further comprising:
alternately pulsing the first pulsed voltage source and the second pulsed voltage source with the biasing controller.
13. The method of claim 1 , further comprising:
generating voltages with a shaped bias waveform with the second pulsed voltage source.
14. The method of claim 1 , further comprising:
generating the second pulsed voltage source with one or more voltages in a continuous range of low to medium voltages of greater than 0 to approximately 1.5 kV.
15. A method for tunable workpiece biasing in a plasma chamber, comprising:
generating a high voltage by a first pulsed voltage source and coupling the high voltage to a workpiece in a plasma chamber;
generating one or more of low and medium voltages by a second pulsed voltage source;
coupling, capacitively, the one or more of low and medium voltages to the workpiece; and
pulsing the high voltage and the one or more of low and medium voltages by a biasing controller, wherein the first pulsed voltage source supplies a high voltage, a maximum of the high voltage during a pulse being approximately 1 to 10 kV, and wherein the second pulsed voltage source supplies one or more voltages in a continuous range of low to medium voltages, wherein the continuous range is greater than 0 to approximately 1.5 kV.
16. The method of claim 15 , further comprising:
generating high voltage pulses at a pulse frequency of approximately 100 Hz to approximately 100,000 Hz with the first pulsed voltage source; and
generating pulses at a pulse frequency of approximately 400 kHz with the second pulsed voltage source.
17. The method of claim 15 , further comprising:
adjusting one or more voltage parameters based on voltages sensed at the workpiece to modify a waveform of the second pulsed voltage source.
18. A system for tunable workpiece biasing, comprising:
a plasma chamber that performs plasma processing on a workpiece;
a first pulsed voltage source using DC voltages, coupled directly to the workpiece in the plasma chamber via at least one direct connection, the at least one direct connection enabling ion energy control in the workpiece near the at least one direct connection;
a second pulsed voltage source coupled capacitively to the workpiece; and
a biasing controller comprising one or more processors, and memory, wherein the memory comprises a set of computer instructions that when executed by the one or more processors, controls the first pulsed voltage source and the second pulsed voltage source, the biasing controller adjusting the first and second pulsed voltage sources in combination to achieve a configurable ion energy distribution in the workpiece.
19. The system of claim 18 , wherein the first pulsed voltage source supplies a first pulse at high voltage, wherein a maximum of the high voltage during a first pulse is approximately in a range of 1 to 10 kV.
20. The system of claim 18 , wherein the biasing controller alternately pulses the first pulsed voltage source and the second pulsed voltage source.