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OUTPUT VOLTAGE AND CURRENT DETERMINATION

IP.com Disclosure Number: IPCOM000251111D
Publication Date: 2017-Oct-12
Document File: 6 page(s) / 124K

Publishing Venue

The IP.com Prior Art Database

Related People

Michael Gilliam Ulrich: INVENTOR

Abstract

The present disclosure is directed to a method and system for determining an output voltage and current for an RF delivery system. Using measurements taken at the input of the matching network and using two-port network parameters of the matching network, the output voltage and current of the RF delivery system can be calculated.

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OUTPUT VOLTAGE AND CURRENT DETERMINATION

BACKGROUND

[0001] An RF delivery system can include an RF generator, an RF cable, and an impedance matching network. Such a system can provide RF power to a load, for example, a plasma chamber

of a semiconductor fabrication system.

[0002] Currently, there is a need to measure the output voltage and current of the RF delivery system for different plasma processes, and to ensure that the output voltage or current does not

exceed a value that could damage the plasma chamber or the RF delivery system. One solution is

to use a capacitive voltage divider at the output of the RF delivery system to measure the output

voltage. When the output voltage is known, the current can be calculated from that value and the

calculated plasma chamber impedance. The output of the RF delivery system, however, can

produce a large range of voltages, including very high voltages having a peak of 10kV or more.

Thus, expensive high-voltage parts must be used for the voltage divider. Further, the use of a

capacitive voltage divider for measuring the output voltage requires additional signal processing

circuitry to convert the RF signals to analog or digital signals. Further, with such a large range of

possible voltages at the output, the measurement of low voltages for certain processes can have a

low resolution. Thus, there is a need for an improved method of measuring the output voltage of

an RF delivery system

BRIEF SUMMARY

[0003] The present disclosure is directed to a method and system for determining an output voltage and current for an RF delivery system. Using measurements taken at the input of the matching

network and using two-port network parameters of the matching network, the output voltage and

current of the RF delivery system can be calculated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0005] Fig. 1 is a block diagram of an RF delivery system and plasma chamber according to one embodiment of the present invention.

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DETAILED DESCRIPTION

[0006] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention or inventions. The description of illustrative

embodiments is intended to be read in connection with the accompanying drawings, which are to

be considered part of the entire written description. In the description of the exemplary

embodiments disclosed herein, any reference to direction or orientation is merely intended for

convenience of description and is not intended in any way to limit the scope of the present

invention. The discussion herein describes and illustrates some possible non-limiting combinations

of features that may exist alone or in other combinations of features. Furthermore, as used herein,

the term "or" is to be interpreted as a logical operator that results in true whenever one or more of

its oper...