Impedance matching using independent capacitance and frequency control

A method of impedance matching comprising:

• operably coupling an RF input of an impedance matching network to an RF source having a variable frequency;
• operably coupling an RF output of the impedance matching network to a plasma chamber having a variable chamber impedance, wherein the impedance matching network further comprises an electronically variable capacitor (EVC) having a variable capacitance, and the impedance matching network is configured to cause an impedance match between the RF source and the plasma chamber;
• operably coupling a first control circuit to the EVC and to a sensor, the first control circuit controlling the EVC and being separate and distinct from a second control circuit controlling the RF source;
• detecting, by the sensor, an RF parameter;
• determining, by the first control circuit, using a match lookup table with a value based on the detected RF parameter, a new EVC configuration for providing a new EVC capacitance,
• altering, by the first control circuit, the EVC to the new EVC configuration;
• and
• altering, by the second control circuit, the variable frequency of the RF source;
• wherein the first control circuit does not provide instructions to the second control circuit for controlling the variable frequency of the RF source.

A method of manufacturing a semiconductor comprising:

• placing a substrate in a plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate;
• and
• energizing plasma within the plasma chamber by coupling RF power from an RF source into the plasma chamber to perform a deposition or etching, and while energizing the plasma, causing an impedance match between the RF source and the plasma chamber by:
• operably coupling an RF input of an impedance matching network to the RF source, the RF source having a variable frequency;
• operably coupling an RF output of the impedance matching network to the plasma chamber, the plasma chamber having a variable chamber impedance, wherein the impedance matching network further comprises an electronically variable capacitor (EVC) having a variable capacitance;
• operably coupling a first control circuit to the EVC and to a sensor, the first control circuit controlling the EVC independently from a second control circuit controlling the RF source;
• detecting, by the sensor, an RF parameter;
• determining, by the first control circuit, using a match lookup table with a value based on the detected RF parameter, new EVC configuration for providing a new EVC capacitance;
• and
• altering, by the first control circuit, the EVC to the new EVC configuration;
• and
• altering by the second control circuit, the variable frequency of the RF source;
• wherein the first control circuit does not provide instructions to the second control circuit for controlling the variable frequency of the RF source.

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 network operably coupled to the plasma chamber, matching circuit comprising:
• an RF input configured to operably couple to an RF source having a variable frequency;
• an RF output configured to operably couple to the plasma chamber, the plasma chamber having a variable chamber impedance;
• an electronically variable capacitor (EVC) having a variable capacitance;
• a first control circuit operably coupled to the EVC and to a sensor configured to detect an RF parameter, the first control circuit controlling the EVC and being separate and distinct from a second control circuit controlling the RF source;
• wherein, to assist in causing an impedance match between the RF source and the plasma chamber, the first control circuit is configured to:
• determine, using a match lookup table with a value based on the detected RF parameter, a new EVC configuration for providing a new EVC capacitance;
• and
• alter the EVC to the new EVC configuration;
• and
• wherein the first control circuit does not provide instructions to the second control circuit for controlling the variable frequency of the RF source, such that, in further causing the impedance match between the RF source and the plasma chamber, the second control circuit alters the variable frequency of the RF source independently from the first control circuit.