Precise Feedback Control of Bias Voltage Tailored Waveform for Plasma Etch Processes

A substrate support system for a plasma processing system, comprising:

• a substrate support having a top surface configured to support a substrate;
• a bias electrode disposed within the substrate support, the bias electrode configured to control a voltage on a top surface of the substrate, the bias electrode connected to receive a bias voltage tailored radiofrequency waveform from a voltage supply system, wherein the bias electrode is configured to electrically receive a first connector for measuring a first voltage on the bias electrode;
• and
• a mid-level electrode disposed within the substrate support such that a lower portion of the substrate support is present between the bias electrode and the mid-level electrode and such that an upper portion of the substrate support is present between the mid-level electrode and the top surface of the substrate support, wherein the mid-level electrode is configured to electrically receive a second connector for measuring a second voltage on the mid-level electrode.

An edge ring system for a plasma processing system, comprising:

• an edge ring configured to circumscribe a substrate support;
• an edge ring electrode disposed within the edge ring, the edge ring electrode configured to control a voltage on a top surface of the edge ring and to receive a bias voltage tailored radiofrequency waveform from a voltage supply system, wherein the edge ring electrode is configured to electrically receive a first connector for measuring a first voltage on the edge ring electrode;
• and
• an edge ring mid-level electrode disposed within the edge ring such that a lower portion of the edge ring is present between the edge ring electrode and the edge ring mid-level electrode and such that an upper portion of the edge ring is present between the edge ring mid-level electrode and the top surface of the edge ring, wherein the edge ring mid-level electrode is configured to electrically receive a second connector for measuring a second voltage on the edge ring mid-level electrode.

A method for controlling voltage on a substrate, comprising:

• operating a voltage supply system to supply a bias voltage tailored radiofrequency waveform to a bias electrode within a substrate support;
• measuring a first voltage on the bias electrode at a given time;
• measuring a second voltage on a mid-level electrode at the given time, the mid-level electrode disposed within the substrate support such that a lower portion of the substrate support is present between the bias electrode and the mid-level electrode and such that an upper portion of the substrate support is present between the mid-level electrode and the top surface of the substrate support;
• and
• using the measured first voltage, the measured second voltage, a capacitance of the lower portion of the substrate support, and a capacitance of the upper portion of the substrate support to determine a voltage on a top surface of a substrate when present on a top surface of the substrate support at the given time.