Impedance transformation in radio-frequency-assisted plasma generation
An apparatus for providing signals to a device may include one or more radio frequency signal generators, and electrically-small transmission line, which coupled signals from the one or more RF signal generators to a fabrication chamber. The apparatus may additionally include a reactive circuit to transform impedance of the electrically-small transmission line from a region of relatively high impedance-sensitivity to region of relatively low impedance-sensitivity.
1. An apparatus for providing signals to a device, comprising:
one or more radiofrequency (RF) signal generators;
one or more electrically-small transmission lines to couple signals from the one or more RF signal generators to a fabrication chamber; and
a reactive circuit to transform impedance of each of the one or more electrically-small transmission lines from a region having a first impedance-sensitivity to a region having a second impedance-sensitivity.
2. The apparatus of claim 1 , wherein the reactive circuit comprises at least series reactance.
3. The apparatus of claim 1 , wherein the reactive circuit comprises at least shunt susceptance.
4. The apparatus of claim 1 , wherein the reactive circuit comprises at least series reactance and shunt susceptance.
5. The apparatus of claim 1 , wherein the region having the first impedance-sensitivity corresponds to a region of relatively high impedance-sensitivity in an impedance space and wherein the real part of the impedance corresponds to a value greater than about 100 ohms.
6. The apparatus of claim 1 , wherein the region having the second impedance-sensitivity corresponds to a region of relatively low impedance-sensitivity in an impedance space and wherein the real part of the impedance corresponds to a value less than about 100 ohms.
7. The apparatus of claim 1 , wherein the reactive circuit to transform the impedance avoids the possibility of a resonant transmission line at any frequency less than the frequency of the signals from the one or more RF signal generators.
8. The apparatus of claim 1 , wherein an electrically-small transmission line of the one or more electrically-small transmission lines corresponds to a transmission line that transforms an impedance from a region of relatively high impedance-sensitivity to a region of relatively low impedance-sensitivity without traversing a transmission line resonance at a frequency less than the frequency of the signal generated by an RF signal generator of the one or more RF signal generators in a medium of the transmission line.
9. The apparatus of claim 1 , wherein a resistive loss of the electrically-small transmission line combined with a loss of the reactive circuit correspond to less than about 20%.
10. The apparatus of claim 1 , wherein a resistive loss of the electrically-small transmission line corresponds to less than 10%.
11. An apparatus, comprising:
an electrically-small transmission line to couple signals from one or more of RF signal generators to a fabrication chamber; and
a reactive circuit to transform impedance of the electrically-small transmission line from a region of relatively high impedance-sensitivity to a region of relatively low impedance-sensitivity, the reactive circuit operating to move an impedance control point in a direction opposite to the direction moved by a length of transmission line.
12. The apparatus of claim 11 , wherein the electrically-small transmission line corresponds to a transmission line that moves the impedance control point from the region of relatively high impedance-sensitivity to the region of relatively low impedance-sensitivity without traversing a transmission line resonance at a frequency less than the frequency of the signal generated by the RF signal generator in a medium of the transmission line.
13. The apparatus of claim 11 , wherein the reactive circuit comprises series capacitive reactance.
14. The apparatus of claim 11 , wherein the reactive circuit comprises at least shunt inductive susceptance.
15. The apparatus of claim 11 , wherein the reactive circuit comprises series capacitive reactance and shunt inductive susceptance.
16. The apparatus of claim 11 , wherein the resistive loss of the electrically-small transmission line combined with the loss of the reactive circuit correspond to less than about 20%.
17. The apparatus of claim 12 , wherein the resistive loss of the electrically-small transmission line corresponds to less than 10%.
18. An integrated circuit fabrication chamber, comprising:
a plurality of integrated circuit fabrication stations;
one or more input ports for coupling a radio frequency (RF) signal to at least one of the plurality of integrated circuit fabrication stations;
an electrically-small transmission line to couple signals from one or more of RF signal generators to the integrated circuit fabrication chamber; and
a reactive circuit to transform impedance of the electrically-small transmission line from a region of relatively high impedance-sensitivity to a region of relatively low impedance-sensitivity.
19. The apparatus of claim 18 , wherein the region of relatively high impedance-sensitivity corresponds to a region in an impedance space and wherein the real part of the impedance corresponds to a value greater than about 100 ohms.
20. The apparatus of claim 18 , wherein the region of relatively low impedance-sensitivity corresponds to a region in an impedance space and wherein the real part of the impedance corresponds to a value less than about 100 ohms.
21. The apparatus of claim 1 , wherein the region having the first impedance-sensitivity corresponds to a region having low impedance-sensitivity and wherein the region having the second impedance-sensitivity corresponds to a region having high impedance-sensitivity.