Systems and methods for using multiple inductive and capacitive fixtures for applying a variety of plasma conditions to determine a match network model

Patent metadata

Field	Value
Publication number	US-2016240356-A1
Application number	US-201615059778-A
Country	US
Kind code	A1
Filing date	Mar 3, 2016
Priority date	May 9, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

Systems and methods for using multiple inductive and capacitive fixtures for applying a variety of plasma conditions to determine fixed parameters of a match network model are described. The multiple fixtures mimic various plasma conditions without occupying tool time in which a wafer is placed within a plasma chamber to generate the fixed parameters of the match network model.

First claim

1 . A method for using multiple fixtures for applying a variety of plasma conditions to determine fixed parameters of a match network model, comprising:
receiving a first output impedance measured at an input of a first fixture; receiving a first input impedance measured at an input of an impedance matching network, wherein the first input impedance is measured when an output of the impedance matching network is connected to the input of the first fixture; receiving a second output impedance measured at an input of a second fixture; receiving a second input impedance measured at the input of the impedance matching network, wherein the second input impedance is measured when the output of the impedance matching network is connected to the input of the second fixture; applying the first measured output impedance and the second measured output impedance at an output of a match network model to calculate a first predicted input impedance at an input of the match network model and a second predicted input impedance at the input of the match network model when the match network model is assigned a first fixed inductance, a first fixed capacitance, and a first fixed resistance; determining whether the first predicted input impedance is within a predetermined range from the first measured input impedance and whether the second predicted input impedance is within the predetermined range from the second measured input impedance; and assigning the first fixed inductance, the first fixed capacitance, and the first fixed resistance to the match network model upon determining that the first predicted input impedance is within the predetermined range from the first measured input impedance and that the second predicted input impedance is within the predetermined range from the second measured input impedance.

2 . The method of claim 1 ,
wherein the first measured input impedance is measured for a first variable capacitance of the impedance matching network when the input of the impedance matching network is connected to an output of a network analyzer operating at a first frequency, wherein the second measured input impedance is measured for a second variable capacitance of the impedance matching network when the input of the impedance matching network is connected to the output of the network analyzer operating at a second frequency, the method further comprising: determining whether the first measured input impedance is within a predetermined threshold of a predetermined impedance; storing the first frequency and the first variable capacitance upon determining that the first measured input impedance is within the predetermined threshold of the predetermined impedance; determining whether the second measured input impedance is within the predetermined threshold of the predetermined impedance; and storing a second frequency and a second variable capacitance upon determining that the second measured input impedance is within the predetermined threshold of the predetermined impedance.

3 . The method of claim 1 , wherein applying the first measured output impedance and the second measured output impedance at the output of the match network model comprises:
applying the first measured output impedance at the output of the match network model to calculate the first predicted input impedance at the input of the match network model when the match network model is assigned a first frequency, a first variable capacitance, the first fixed inductance, the first fixed capacitance, and the first fixed resistance; and applying the second measured output impedance at the output of the match network model to calculate the second predicted input impedance at the input of the match network model when the match network model is assigned a second frequency, a second variable capacitance, the first fixed inductance, the first fixed capacitance, and the first fixed resistance.

4 . The method of claim 1 , wherein the first measured input impedance is measured by a network analyzer, wherein the first measured input impedance is a complex value, wherein the input of the impedance matching network is configured to be coupled to a branch circuit of the impedance matching network, wherein the branch circuit is configured to be coupled to an RF generator during processing of a wafer.

5 . The method of claim 1 , wherein the first measured input impedance is measured for a first variable capacitance of the impedance matching network when the input of the impedance matching network is connected to an output of a network analyzer operating at a first frequency, wherein the first variable capacitance of the impedance matching network is a combined variable capacitance of one or more variable capacitors of the impedance matching network.

6 . The method of claim 1 , wherein the first fixture is a load impedance fixture for obtaining an S11 measurement and the second fixture is a load impedance fixture for obtaining an S11 measurement.

7 . The method of claim 1 , wherein the second input impedance is measured by a network analyzer, wherein the second input impedance is a complex value, wherein the input of the impedance matching network is configured to be coupled to a branch circuit of the impedance matching network, wherein the branch circuit is configured to be coupled to an RF generator during processing of a wafer.

8 . The method of claim 1 , wherein the second measured input impedance is measured for a second variable capacitance of the impedance matching network when the input of the impedance matching network is connected to an output of a network analyzer operating at a second frequency, wherein the second variable capacitance of the impedance matching network is a combined variable capacitance of one or more variable capacitors of the impedance matching network.

9 . The method of claim 1 , wherein determining whether the first predicted input impedance is within the predetermined range from the first measured input impedance is performed simultaneously with determining whether the second predicted input impedance is within the predetermined range from the second measured input impedance.

10 . The method of claim 1 , further comprising calculating an output value of a variable at the output of the match network model during a time the match network model is assigned the first fixed inductance, the first fixed capacitance, and the first fixed resistance, wherein calculating the output value of the variable is performed by forward propagating an input value of the variable measured by a sensor connected to an output of an RF generator.

11 . A system for using multiple fixtures for applying a variety of plasma conditions to determine fixed parameters of a match network model, comprising:
a processor configured to receive a first output impedance measured at an input of a first fixture, wherein the processor is configured to receive a first input impedance measured at an input of an impedance matching network, wherein the first measured input impedance is measured when an output of the impedance matching network is connected to the input of the first fixture, wherein the processor is configured to receive a second output impedance measured at an input of a second fixture, wherein the processor is configured to receive a second input impedance measured at the input of the impedance matching network, wherein the second measured input impedance is measured when the output of the impedance matching network is connected to the input of the second fixture, wherein the processor is configured to apply the first measured output impedance at an output of a match network model and the second measured output impedance at the output of th

Assignees

• Lam Res Corp

Inventors

• Howald Arthur M
• Valcore Jr John C

Classifications

• G01R17/00

  Measuring arrangements involving comparison with a reference value, e.g. bridge · CPC title

• H01J37/32926 Primary

  Software, data control or modelling · CPC title

• H01J37/32091

  the radio frequency energy being capacitively coupled to the plasma · CPC title

• G01R27/04

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title

• H01J37/32183

  Matching circuits · CPC title