RF impedance matching network with clamping circuit

A method of matching an impedance comprising:

• coupling a radio frequency (RF) input of a matching circuit to an RF source providing an RF signal;
• coupling an RF output of the matching circuit to a plasma chamber, wherein the matching circuit comprises:
• at least one electronically variable capacitor (EVC), wherein each EVC of the at least one EVC comprises fixed capacitors, each of the fixed capacitors having a corresponding switching circuit for switching in and out the fixed capacitor to alter a total capacitance of the EVC;
• and
• a control circuit configured to cause the switching in and out of the fixed capacitors of each EVC to enable an impedance match;
• wherein each switching circuit for each fixed capacitor of each EVC comprises:
• a switch comprising a PIN diode or an NIP diode;
• a driver circuit operably coupled to the switch;
• a filter operably coupled between the driver circuit and the switch;
• and
• a clamping circuit distinct from the driver circuit and operably coupled between the filter and the switch, the clamping circuit comprising a blocking device having a first terminal operably coupled to a clamping power supply and a distinct second terminal operably coupled to a terminal of the filter;
• and
• matching an impedance by at least one of the switching circuits of the at least one EVC switching in or out its corresponding fixed capacitor to alter a total capacitance of the EVC.

A semiconductor processing tool comprising:

• a plasma chamber configured to deposit a material onto a substrate or etch a material from the substrate;
• and
• an impedance matching circuit operably coupled to the plasma chamber, the matching circuit comprising:
• an RF input configured to operably couple to an RF source providing an RF signal;
• an RF output configured to operably couple to the plasma chamber;
• at least one electronically variable capacitor (EVC), wherein each EVC of the at least one EVC comprises fixed capacitors, each of the fixed capacitors having a corresponding switching circuit for switching in and out the fixed capacitor to alter a total capacitance of the EVC;
• and
• a control circuit configured to cause the switching in and out of the fixed capacitors of each EVC to enable an impedance match;
• wherein each switching circuit for each fixed capacitor of each EVC comprises:
• a switch comprising a PIN diode or an NIP diode;
• a driver circuit operably coupled to the switch;
• a filter operably coupled between the driver circuit and the switch;
• and
• a clamping circuit distinct from the driver circuit and operably coupled between the filter and the switch, the clamping circuit comprising a blocking device having a first terminal operably coupled to a clamping power supply and a distinct second terminal operably coupled to a terminal of the filter.