| 主权项 |
1. An impedance matching circuit comprising:
a first circuit including a first plurality of tuning elements defined along a path, the first circuit having an input coupled to a kilohertz (kHz) radio frequency (RF) generator, wherein the first circuit is coupled to an output; a second circuit having a second plurality of tuning elements, wherein the second circuit has an input coupled to a megahertz (MHz) RF generator and is coupled to the output; wherein the output of the first and second circuits is coupled to an input of an RF transmission line that is coupled to an electrode of a plasma chamber used for processing semiconductor substrates, and a uniformity control circuit defined from at least one of the plurality of tuning elements of the first circuit, wherein the uniformity control circuit is connected serially along the path of the first circuit to define a capacitance that at least partially influences a radial uniformity profile in an etch rate produced by the plasma chamber, wherein a change in the capacitance causes an adjustment in the radial uniformity profile, wherein the kHz RF generator is configured to operate in a range of 50 kHz to less than 1000 kHz. |
