Diagnosis system for pulsed plasma

Patent metadata

Field	Value
Publication number	US-9564295-B2
Application number	US-201514827347-A
Country	US
Kind code	B2
Filing date	Aug 17, 2015
Priority date	Nov 4, 2014
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A diagnosis system for pulsed plasma includes an optical emission sensor (OES) to receive light generated the pulsed plasma, the pulsed plasma having been generated in accordance with a pulse signal, a digitizer to synchronize the electrical signal with the pulse signal, and an analyzer to analyze the synchronized electrical signal.

First claim

What is claimed is:

1. A diagnosis system for pulsed plasma, the diagnosis system comprising:
a chamber in which light is to be generated by a reaction between a substrate and the pulsed plasma;
a first pulsed RF power supply to provide a first pulsed RF power corresponding to a pulse signal to the chamber;
an optical emission sensor (OES) to sense generated light and convert the generated light into an electrical signal;
a digitizer to synchronize the electrical signal with the pulse signal; and
an analyzer to analyze the synchronized electrical signal, wherein
a period of the pulse signal is divided into a pulse-on period and a pulse-off period, and
the analyzer is to determine at least one from among a first maximum signal magnitude value defined as the maximum electrical signal magnitude value in the pulse-on period, a first maximum signal time when the first maximum signal magnitude value occurs, a first minimum signal magnitude value defined as the minimum electrical signal magnitude value in the pulse-on period, a first minimum signal time when the first minimum signal magnitude value occurs, a first average signal magnitude value defined as an average of an electrical signal magnitude value in the pulse-on period, a first standard deviation value defined as a standard deviation corresponding to the first average signal magnitude value, a second maximum signal magnitude value defined as the maximum electrical signal magnitude value in the pulse-off period, a second maximum signal time when the second maximum signal magnitude value occurs, a second minimum signal magnitude value defined as the minimum electrical signal magnitude value in the pulse-off period, a second minimum signal time when the second minimum signal magnitude value occurs, a second average signal magnitude value defined as an average of an electrical signal magnitude value in the pulse-off period, and a second standard deviation value defined as a standard deviation corresponding to the second average signal magnitude value.

2. The diagnosis system as claimed in claim 1 , wherein the optical emission sensor is a photo multiplier tube (PMT).

3. The diagnosis system as claimed in claim 2 , wherein the photo multiplier tube and the digitizer have a nanosecond time resolution.

4. The diagnosis system as claimed in claim 1 , wherein the pulse signal is supplied to the digitizer by electrical T-branching of a signal generated by the first pulsed RF power supply or by direct connection from the first pulsed RF power supply.

5. The diagnosis system as claimed in claim 1 , wherein the analyzer is to determine a magnitude of the pulsed plasma at a specific time.

6. The diagnosis system as claimed in claim 1 , wherein:
a period of the pulse signal is divided into a pulse-on period and a pulse-off period, and
the analyzer is to analyze the synchronized electrical signal from a start point of the pulse-on period or the pulse-off period.

7. The diagnosis system as claimed in claim 6 , wherein:
a period of the pulse signal is divided into a pulse-on period and a pulse-off period, and
the analyzer is to determine a magnitude of the electrical signal in the pulse-on period or a magnitude of the electrical signal in the pulse-off period.

8. The diagnosis system as claimed in claim 1 , wherein:
the analyzer is to determine a period of the pulsed plasma, and
the period of the pulsed plasma is measured based on a time difference between times when the first maximum signal occurs, a time difference between times when the first minimum signal occurs, a time difference between times when the second maximum signal occurs, or a time difference between times when the second minimum signal occurs.

9. The diagnosis system as claimed in claim 8 , wherein:
the period of the pulsed plasma is divided into a duty-on period defined from a first point in time when the electrical signal magnitude value becomes equal to or greater than a start threshold level in the pulse-on period to a first point in time when the electrical signal magnitude value becomes equal to or less than an end threshold level outside the pulse-on period, and a duty-off period defined as a remaining period of the period of the pulsed plasma excluding the duty-on period, and
the analyzer is to determine a duty ratio equal to a ratio of the duty-on period to the period of pulsed plasma.

10. The diagnosis system as claimed in claim 1 , wherein the analyzer is to analyze the synchronized electrical signal over at least two periods of the pulse signal.

11. The diagnosis system as claimed in claim 10 , wherein the analyzer is to determine a period of the pulsed plasma and to compare the period of the pulsed plasma to the period of the pulse signal.

12. The diagnosis system as claimed in claim 1 , further comprising:
a second pulsed RF power supply to provide to second pulsed RF power in accordance with the pulse signal to the chamber.

13. The diagnosis system as claimed in claim 12 , wherein the first and second pulsed RF power supplies commonly include a pulse controller to generate the pulse signal.

14. The diagnosis system as claimed in claim 12 , wherein each of the first and second pulsed RF power supplies includes a pulse RF generator to generate the pulse signal.

15. An etching apparatus, comprising:
a chamber in which light is to be generated by an etching reaction between a substrate and a pulsed plasma;
a pulsed RF power supply to provide to pulsed RF power in accordance with a pulse signal to the chamber;
an optical emission sensor to output an electrical signal obtained by electrically converting the generated light;
a digitizer to synchronize the electrical signal with the pulse signal;
a detector to detect an etch end point time based on a magnitude of the synchronized electrical signal; and
an analyzer to analyze the synchronized electrical signal, wherein:
a period of the pulse signal is divided into a pulse-on period and a pulse-off period, and
the analyzer is to determine at least one from among:
a first maximum signal magnitude value defined as the maximum electrical signal magnitude value in the pulse-on period,
a first maximum signal time when the first maximum signal magnitude value occurs, a first minimum signal magnitude value defined as the minimum electrical signal magnitude value in the pulse-on period,
a first minimum signal time when the first minimum signal magnitude value occurs,
a first average signal magnitude value defined as an average of an electrical signal magnitude value in the pulse-on period,
a first standard deviation value defined as a standard deviation corresponding to the first average signal magnitude value,
a second maximum signal magnitude value defined as the maximum electrical signal magnitude value in the pulse-off period,
a second maximum signal time when the second maximum signal magnitude value occurs,
a second minimum signal magnitude value defined as the minimum electrical signal magnitude value in the pulse-off period,
a second minimum signal time when the second minimum signal magnitude value occurs,
a second average signal magnitude value defined as an average of an electrical signal magnitude value in the pulse-off period, and
a second standard deviation value defined as a standard deviation corresponding to the second average signal magnitude value.

16. A diagnosis system for pulsed plasma, comprising:
an optical emission sensor (OES) to receive light generated by the pulsed plasma and output an electrical signal in accordance with the light, the pulsed plasma having been generated in

Assignees

• Samsung Electronics Co Ltd

Inventors

• Lee Dong-Soo
• Jang Sung-Ho
• Kim Byeong-Hee
• Sung Doug-Yong
• Shin Dong-Ok

Classifications

• H05H1/0006 Primary

  Investigating plasma, e.g. measuring the degree of ionisation or the electron temperature · CPC title

• H01J37/32091

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

• G01J2001/4238

  Pulsed light · CPC title

• H01J37/32935

  Monitoring and controlling tubes by information coming from the object and/or discharge · CPC title

• G01J1/44

  Electric circuits {(for command of an exposure part G03B7/02)} · CPC title