Pulsed plasma analyzer and method for analyzing the same

• US 10,249,485 B2
• Filed: 10/06/2017
• Issued: 04/02/2019
• Est. Priority Date: 11/10/2016
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Volynets, Vladimir, Vladimir, Protopopov, Kim, Young Do, Barsukov, Yuri, Lee, Sang Heon, Jang, Sung Ho
• Primary Examiner(s): Nur, Abdullahi
• Application Number:
  US15/727,198
• Publication Number:
  US 20180130651A1
• Time in Patent Office: 543 Days
• CPC Class Codes: C23C 16/45502 Flow conditions in reaction chamber
• CPC Class Codes: G01J 3/2889 Rapid scan spectrometers; Time resolved spectrometry
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: H01J 2237/327 Arrangements for generating the plasma
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01J 49/0031 Step by step routines describing the use of the apparatus H01J49/0081 takes precedence
• CPC Class Codes: H01J 49/10 Ion sources; Ion guns
• CPC Class Codes: H01J 49/12 using an arc discharge, e.g. of the duoplasmatron type
• CPC Class Codes: H01J 49/40 Time-of-flight spectrometers H01J49/36 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

A pulsed plasma analyzer includes a pulse modulator that controls an off-time of a pulsed plasma that includes a target radical, an optical spectrometer that measures optical emissions of the pulsed plasma after the off-time to determine optical emission data, and a concentration estimating module that estimates a concentration of the target radical during the off-time based on an initial optical emission value of the optical emission data that changes as a function of the off-time, and outputs an estimated concentration.

Claims

1. A pulsed plasma analyzer comprising:

a pulse modulator that controls an off-time of a pulsed plasma that includes a target radical;

an optical spectrometer that measures optical emissions of the pulsed plasma after the off-time and outputs optical emission data; and

a concentration estimating module that estimates a concentration of the target radical during the off-time, based on an initial optical emission value of the optical emission data that changes as a function of the off-time, and outputs the estimated concentration.

2. The pulsed plasma analyzer of claim 1, wherein the optical spectrometer measures the optical emissions of the pulsed plasma after the off-time by a time-gated method.

3. The pulsed plasma analyzer of claim 1, wherein the concentration estimating module estimates a fitting function that fits the estimated concentration and estimates a lifetime of the target radical based on the fitting function.

4. The pulsed plasma analyzer of claim 3, wherein the lifetime of the target radical is a time (Tl) wherein the fitting function (FF) has a value FF(Tl) expressed by FF(Tl)=R0/e,

wherein R0 represents the concentration of the target radical when the off-time is 0, and e is the base of a natural logarithm.

5. The pulsed plasma analyzer of claim 1, further comprising:

a time-resolved actinometry (TRA) module which normalizes the optical emission data according to Jn=Jr/Ja, wherein Jn represents the normalized optical emission data, Jr represents optical emission data of the target radical in the optical emission data, and Ja represents optical emission data of the actinometer in the optical emission data, to estimate normalized optical emission data (Jn),

wherein the pulsed plasma further comprises an actinometer, and

the concentration estimating module estimates the concentration of the target radical during the off-time based on the initial optical emission value of the normalized optical emission data, and outputs the estimated concentration.

6. The pulsed plasma analyzer of claim 5, wherein the optical emission data is estimated by measuring the optical emission of the pulsed plasma after the off-time by a time-gated method.

7. The pulsed plasma analyzer of claim 5, wherein the actinometer comprises argon (Ar).

8. A plasma device comprising:

a pulsed plasma that includes a pulse generator that generates a pulse having first and second levels, and a plasma chamber in which a plasma containing a target radical is generated while a second level pulse is applied; and

a radical concentration estimator that estimates a concentration of the target radical while a first level pulse is applied,

wherein the radical concentration estimator measures optical emissions of the plasma while changing a duration of the first level pulse, and estimates the concentration of the target radical while the second level pulse is applied based on the measured optical emission.

9. The plasma device of claim 8, wherein the radical concentration estimator measures the optical emissions of the target radical by a time-gated method.

10. The plasma device of claim 8, wherein the plasma further comprises an actinometer, and

the radical concentration estimator normalizes the measured optical emissions using the optical emission of the actinometer, and estimates the concentration of the target radical during application of the first level pulse based on the normalized optical emissions.

11. The plasma device of claim 10, wherein the actinometer comprises argon (Ar).

12. The plasma device of claim 8, wherein the radical concentration estimator estimates a fitting function that fits the estimated concentration, and estimates a lifetime of the target radical based on the fitting function.

13. The plasma device of claim 12, wherein the lifetime of the target radical is a time (Tl) wherein the fitting function (FF) has a value FF(Tl) expressed by FF(Tl)=R0/e, wherein R0 represents the concentration of the target radical when the time of the duration of the first level pulse is 0, and e is the base of a natural logarithm.

14. A method of operating a pulsed plasma analyzer, comprising the steps of:

providing a pulsed voltage into a plasma chamber to generate a pulsed plasma inside the plasma chamber;

initializing an off-time of the pulsed plasma and a counter which counts a number of changes of the off-time;

measuring optical emissions of the pulsed plasma;

estimating a concentration of a target radical during the off-time based on changes of initial optical emission values of the optical emission data during the off-time, when the counter is equal to a preset maximum;

determining a fitting function that fits the estimated concentration; and

estimating a lifetime of the target radical as a time when a value of the fitting function falls below a preset value.

15. The method of claim 14, wherein the optical emissions are measured using a time-gated method.

16. The method of claim 14, further comprising adjusting the off-time of the pulsed plasma and incrementing the counter, when the counter is not equal to the preset maximum.

17. The method of claim 14, wherein the concentration [R] of the target radicals R during the off-time is estimated from J(t)=k(Te,t)·

ne(t)·

[R](t)≈

K1·

[R](t),

wherein k(Te, t) represents the temperature Te of electrons in the plasma chamber at time t, ne(t) represents the density of electrons in the plasma chamber at time t, [R](t) represents the radical concentration at time t, and K1 is a constant.

18. The method of claim 14, wherein the lifetime RL of the target radical R is determined as a time Tl when the fitting function FF has a value FF(Tl) expressed by FF(Tl)=R0/e, where FF is the fitting function, R0 is the concentration of the target radical when the off-time is 0, and e is the base of the natural logarithms.

19. The method of claim 14, further comprising normalizing the optical emission data by optical emission data Jn of an actinometer to output normalized optical emission data according to Jn=Jr/Ja, wherein Jn represents the normalized optical emission data, Jr represents optical emission data of the target radical in the optical emission data, and Ja represents optical emission data of the actinometer in the optical emission data.