US 9,210,790 B2Granted

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

AssigneeAdvanced Energy Industries, Inc.

InventorsDaniel J. Hoffman, Daniel Carter, Victor Brouk, William J. Hattel

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Abstract

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.

Claims28

Dependent claims

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.

10 more elements

A system comprising:

a bias supply providing a modified periodic voltage, the bias supply comprising:
a power supply configured to provide a periodic voltage function to an output;
an ion current compensation component coupled to the output and configured to modify the periodic voltage function with an ion compensation current so that the bias supply provides the modified periodic voltage function;
and
a controller configured to provide instructions to the power supply to adjust the periodic voltage function and to provide instructions to the ion current compensation component to adjust the ion compensation current;
a calibration component, separate from the bias supply and coupled to the output to receive the modified periodic voltage function, the calibration component comprising:
a load emulator having:
circuitry configured to emulate impedance, rectifying effects, ion current and capacitive characteristics of a plasma load without generating any plasma, the load emulator further configured to receive the modified periodic voltage function, and wherein;
the capacitive characteristics comprise a sheath capacitance and an effective capacitance, and
the circuity configured to emulate rectifying effects comprises reverse biased components when the load emulator emulates a plasma load without generating any plasma;
a measurement component configured to make one or more measurements of the modified periodic voltage function as it interacts with the circuitry of the load emulator;
and
an analysis component configured to generate and store calibration data by comparing at least one measured value from the measurement component and at least one expected value from the bias supply wherein the calibration data is subsequently utilized to more accurately effectuate ion energy in an actual plasma during plasma processing.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/597,032Filed 28 Aug 2012
Published: US 2014/0062303 A16 Mar 2014
Granted: 8 Dec 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

H05H 1/46
Generating plasma: using applied electromagnetic fields, e.g. high frequency or microwave energy
C23C 14/345
Applying energy to the substrate during sputtering: using substrate bias
H01J 37/32082
Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources: radio frequency generated…
H01J 37/32422
Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources: arrangement for selecting…