Pulsed voltage compensation for plasma processing applications
AssigneeApplied Materials, Inc.
InventorsShreeram Jyoti Dash, Michael Thomas Nichols
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Abstract
Embodiments provided herein generally include apparatus, e.g., plasma processing systems, and methods for the plasma processing of a substrate in a processing chamber. Some embodiments are directed to a method for waveform generation, which generally includes delivering a first waveform with an associated setpoint from an energy source; detecting at least one characteristic of the first waveform; estimating a voltage decay during a portion of a pulse during the first waveform; calculating a compensation factor; and adjusting the at least one characteristic using the compensation factor to adjust a voltage decay.
Claims20
A method for waveform generation, comprising:
- delivering a first waveform with an associated setpoint from an energy source;
- detecting at least one characteristic of the first waveform using at least one sensor;
- determining a voltage decay value during a portion of a pulse provided within the first waveform by use of the detected at least one characteristic and at least one empirically stored voltage decay value function previously derived from wafer-level measurements performed with a wired wafer;
- determining a sheath coupling voltage value during the portion of the pulse of the first waveform by use of the detected at least one characteristic and at least one empirically stored sheath coupling voltage value function;
- calculating a compensation factor based on the determined voltage decay value and the determined sheath coupling voltage value;
- and
- adjusting at least one characteristic of the first waveform by applying the calculated compensation factor to the at least one characteristic of the first waveform during an ion current stage to maintain a substantially constant sheath potential.
A waveform generator, comprising:
- a sensor assembly coupled to an output of a pulser, wherein the sensor assembly comprises at least one sensor configured to detect at least one characteristic of a first waveform generated by the waveform generator;
- and
- a system controller coupled to the waveform generator, wherein the system controller comprises:
- a processor and memory, wherein the memory includes instructions which when executed by the processor causes:
- an amount of voltage decay within a portion of a pulse during the first waveform to be determined using at least one empirically stored voltage decay value function previously derived from wafer-level measurements performed with a wired wafer;
- an amount of a sheath coupling voltage within the portion of a pulse of the first waveform to be determined using at least one empirically stored sheath coupling voltage value function;
- a compensation factor based on the determined amount of voltage decay and the determined amount of sheath coupling voltage to be calculated;
- and
- the at least one characteristic of the first waveform to be adjusted based on the application of the calculated compensation factor during an ion current stage to maintain a substantially constant sheath potential.
Dependencies are inferred from the claim text.