Multiple-output radiofrequency matching module and associated methods
A matching module includes an input terminal connected to an input node, a variable load capacitor, and a plurality of RF signal delivery branches. The input terminal is connected to receive RF signals from one or more RF generators. The load capacitor is connected between the input node and a reference ground potential. Each of the plurality of RF signal delivery branches has a respective ingress terminal connected to the input node and a respective egress terminal connected to a respective one of a plurality of output terminals. Each of the plurality of output terminals of the matching module is connected to deliver RF signals to a different one of a plurality of plasma processing stations/chambers. Each of the plurality of RF signal delivery branches includes a corresponding inductor and a corresponding variable tuning capacitor electrically connected in a serial manner between its ingress terminal and its egress terminal.
1. An impedance control system, comprising:
an input terminal for receiving radiofrequency (RF) signals from at least one RF generator;
a plurality of output terminals for delivering RF signals to a plurality of plasma processing systems;
a first impedance control device electrically connected to the input terminal; and
a plurality of branch circuits, each of the plurality of branch circuits electrically connected between the input terminal and a corresponding one of the plurality of output terminals, each of the plurality of branch circuits including at least one branch-level impedance control device.
2. The impedance control system as recited in claim 1 , wherein the first impedance control device is connected to simultaneously control an impedance of each of the plurality of branch circuits.
3. The impedance control system as recited in claim 1 , wherein the first impedance control device is configured as a variable capacitor electrically connected between the input terminal and a reference ground potential.
4. The impedance control system as recited in claim 1 , wherein the at least one branch-level impedance control device in any given one of the plurality of branch circuits is independently controllable with respect to other impedance control devices in others of the plurality of branch circuits.
5. The impedance control system as recited in claim 1 , wherein the at least one branch-level impedance control device includes a variable capacitor.
6. The impedance control system as recited in claim 5 , wherein the variable capacitor within a given one of the plurality of branch circuits is electrically connected in a serial manner between the input terminal and a given one of the plurality of output terminals to which the given one of the plurality of branch circuits is electrically connected.
7. The impedance control system as recited in claim 1 , wherein each of the plurality of branch circuits includes at least two branch-level impedance control devices.
8. The impedance control system as recited in claim 7 , wherein the at least two branch-level impedance control devices are independently controllable with respect to each other.
9. The impedance control system as recited in claim 8 , wherein each of the at least two branch-level impedance control devices in any given one of the plurality of branch circuits is independently controllable with respect to other impedance control devices in others of the plurality of branch circuits.
10. The impedance control system as recited in claim 7 , wherein the at least two branch-level impedance control devices includes an inductor.
11. The impedance control system as recited in claim 10 , wherein the inductor within a given one of the plurality of branch circuits is electrically connected in a serial manner between the input terminal and a given one of the plurality of output terminals to which the given one of the plurality of branch circuits is electrically connected.
12. The impedance control system as recited in claim 11 , wherein the at least two branch-level impedance control devices includes a variable capacitor.
13. The impedance control system as recited in claim 12 , wherein the variable capacitor within a particular one of the plurality of branch circuits is electrically connected in a serial manner between the input terminal and a particular one of the plurality of output terminals to which the particular one of the plurality of branch circuits is electrically connected.
14. The impedance control system as recited in claim 12 , wherein the variable capacitor is a first variable capacitor, wherein the at least two branch-level impedance control devices includes a second variable capacitor.
15. The impedance control system as recited in claim 14 , wherein the first variable capacitor within a particular one of the plurality of branch circuits is electrically connected in a serial manner between the input terminal and a particular one of the plurality of output terminals to which the particular one of the plurality of branch circuits is electrically connected, and
wherein the second variable capacitor within the particular one of the plurality of branch circuits is electrically connected between the particular one of the plurality of output terminals to which the particular one of the plurality of branch circuits is electrically connected and a reference ground potential.
16. The impedance control system as recited in claim 15 , wherein the first impedance control device is variable load capacitor electrically connected between the input terminal and the reference ground potential.
17. The impedance control system as recited in claim 16 , wherein the variable load capacitor and the first variable capacitor in each of the plurality of branch circuits are set to respective capacitance values that provide a substantial match between an impedance present at the input terminal and an output impedance of the at least one RF generator.
18. The impedance control system as recited in claim 16 , wherein the variable load capacitor and the first variable capacitor in each of the plurality of branch circuits are set to respective capacitance values that provide a prescribed distribution of one or more RF signal delivery parameters across the plurality of output terminals, wherein the one or more RF signal delivery parameters includes one or more of power, phase, current, impedance, and voltage.
19. The impedance control system as recited in claim 18 , wherein the prescribed distribution is a substantially equal distribution of the one or more RF signal delivery parameters across the plurality of output terminals.
20. The impedance control system as recited in claim 18 , wherein the prescribed distribution includes at least two different values of at least one of the one or more RF signal delivery parameters across the plurality of output terminals.