Using modeling to determine ion energy associated with a plasma system
First Claim
1. A method for determining ion energy, the method comprising:
- receiving, by a host computer system from a voltage and current probe, a first complex voltage and current measured at an output of a radio frequency (RF) generator by the voltage and current probe, wherein the voltage and current probe is coupled to the output of the RF generator for measuring the first complex voltage and current and is located within the RF generator, wherein the output of the RF generator is coupled via an RF cable to an input of an impedance matching circuit, wherein said receiving of the first complex voltage and current is performed when the RF generator is coupled to a plasma chamber via the impedance matching circuit, the impedance matching circuit having an output coupled to an RF transmission line;
generating, by the host computer system, an impedance matching model based on electrical components defined in the impedance matching circuit, the impedance matching model having an input and an output, the input of the impedance matching model receiving the first complex voltage and current from the voltage and current probe, the impedance matching model having one or more elements;
propagating, by the host computer system, the first complex voltage and current through the elements of the impedance matching model to determine a second complex voltage and current;
obtaining, by the host computer system, a peak voltage from the second complex voltage and current;
determining, by the host computer system, a wafer bias based on the second complex voltage and current;
determining, by the host computer system, the ion energy based on the wafer bias and the peak voltage; and
controlling the RF generator based on the ion energy.
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Accused Products
Abstract
Systems and methods for determining ion energy are described. One of the methods includes detecting output of a generator to identify a generator output complex voltage and current (V&I). The generator is coupled to an impedance matching circuit and the impedance matching circuit is coupled to an electrostatic chuck (ESC). The method further includes determining from the generator output complex V&I a projected complex V&I at a point along a path between an output of a model of the impedance matching circuit and a model of the ESC. The operation of determining of the projected complex V&I is performed using a model for at least part of the path. The method includes applying the projected complex V&I as an input to a function to map the projected complex V&I to a wafer bias value at the ESC model and determining an ion energy from the wafer bias value.
244 Citations
23 Claims
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1. A method for determining ion energy, the method comprising:
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receiving, by a host computer system from a voltage and current probe, a first complex voltage and current measured at an output of a radio frequency (RF) generator by the voltage and current probe, wherein the voltage and current probe is coupled to the output of the RF generator for measuring the first complex voltage and current and is located within the RF generator, wherein the output of the RF generator is coupled via an RF cable to an input of an impedance matching circuit, wherein said receiving of the first complex voltage and current is performed when the RF generator is coupled to a plasma chamber via the impedance matching circuit, the impedance matching circuit having an output coupled to an RF transmission line; generating, by the host computer system, an impedance matching model based on electrical components defined in the impedance matching circuit, the impedance matching model having an input and an output, the input of the impedance matching model receiving the first complex voltage and current from the voltage and current probe, the impedance matching model having one or more elements; propagating, by the host computer system, the first complex voltage and current through the elements of the impedance matching model to determine a second complex voltage and current; obtaining, by the host computer system, a peak voltage from the second complex voltage and current; determining, by the host computer system, a wafer bias based on the second complex voltage and current; determining, by the host computer system, the ion energy based on the wafer bias and the peak voltage; and controlling the RF generator based on the ion energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A plasma system for determining an ion energy, comprising:
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an RF generator for generating a radio frequency (RF) signal, the RF generator associated with a voltage and current probe, wherein the voltage and current probe is coupled to an output of the RF generator to measure a first complex voltage and current at the output of the RF generator and is located within the RF generator; an impedance matching circuit coupled to the RF generator, wherein the output of the RF generator is coupled via an RF cable to an input of the impedance matching circuit; a plasma chamber coupled to the impedance matching circuit via an RF transmission line, the impedance matching circuit having an input coupled to the output of the RF generator and an output coupled to the RF transmission line; and a processor coupled to the RF generator, the processor configured to; receive the first complex voltage and current from the voltage and current probe; generate an impedance matching model based on electrical components defined in the impedance matching circuit, the impedance matching model having an input and an output, the input of the impedance matching model receiving the first complex voltage and current, the impedance matching model having one or more elements; propagate the first complex voltage and current through the elements of the impedance matching model to determine a second complex voltage and current; obtain a peak voltage from the second complex voltage and current; determine a wafer bias based on the second complex voltage and current; determine the ion energy based on the wafer bias and the peak voltage; and control the RF generator based on the ion energy. - View Dependent Claims (20, 21)
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22. A computer system for determining an ion energy, the computer system comprising:
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a processor configured to receive, from a voltage and current probe, a first complex voltage and current measured at an output of a radio frequency (RF) generator by the voltage and current probe, wherein the output of the RF generator is coupled via an RF cable to an input of an impedance matching circuit, wherein the voltage and current probe is located within the RF generator, wherein the processor is configured to receive the first complex voltage and current when the RF generator is coupled to a plasma chamber via the impedance matching circuit, the impedance matching circuit having an output coupled to an RF transmission line, wherein the processor is further configured to; generate an impedance matching model based on electrical components defined in the impedance matching circuit, the impedance matching model having an input and an output, the input of the impedance matching model receiving the first complex voltage and current, the impedance matching model having one or more elements; propagate the first complex voltage and current through the elements of the impedance matching model to determine a second complex voltage and current; obtain a peak voltage from the second complex voltage and current; determine a wafer bias based on the second complex voltage and current; determine the ion energy based on the wafer bias and the peak voltage; and control the RF generator based on the ion energy; and a memory device coupled to the processor, the memory device configured to store the ion energy. - View Dependent Claims (23)
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Specification