Systems and methods for calibrating a switched mode ion energy distribution system

摘要

Systems, methods and apparatus for regulating ion energies and ion energy distributions along with calibrating a bias source and a plasma processing chamber are disclosed. An exemplary method includes applying a periodic voltage function to a load emulator, which emulates electrical characteristics of a plasma load and associated electronics such as an e-chuck. The load emulator can be measured for various electrical parameters and compared to expected parameters generated by the bias source. Differences between measured and expected values can be used to identify and correct faults and abnormalities in the bias supply, the chamber, or a power source used to ignite and sustain the plasma. Once the bias supply is calibrated, the chamber can be calibrated by measuring and calculating an effective capacitance comprising a series and parallel capacitance of the substrate support and optionally the substrate.

主权项

1. A method of calibrating a bias supply configured to generate a potential on a top surface of a substrate during plasma processing of the substrate, the method comprising:
emulating a plasma sheath capacitance with a variable capacitance circuit of a plasma load emulator without generating any plasma; emulating plasma ion current with a variable current source without generating any plasma; receiving a modified periodic voltage function from the bias supply comprising pulses and a portion between the pulses; receiving an expected ion energy; receiving an expected ion current; delivering the modified periodic voltage function to a plasma load emulator; measuring a voltage across the variable capacitance circuit of the plasma load emulator; applying a known current from the variable current source of the plasma load emulator to the variable capacitance circuit to emulate the ion current; comparing the voltage across the variable capacitance circuit of the plasma load emulator to the expected ion energy and determining an ion energy error from this comparing; comparing the known current from the variable current source of the plasma load emulator to the expected ion current and determining an ion current error from this comparing; generating calibration data with the ion energy error and the ion current error; and storing the calibration data in a calibration data store in the bias supply, wherein the calibration data is subsequently utilized to more accurately effectuate ion energy in an actual plasma during the plasma processing of the substrate.