Monitoring system comprising infrared thermopile detector

• US 7,351,976 B2
• Filed: 10/31/2006
• Issued: 04/01/2008
• Est. Priority Date: 05/08/2002
• Status: Expired due to Term

• Current Assignee: Entegris Incorporated
• Original Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Inventors: Arno, Jose I.
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): VU, MINDY D
• Application Number:
  US11/555,094
• Publication Number:
  US 20070200065A1
• Time in Patent Office: 518 Days
• Field of Search: 250/343
• US Class Current: 250/343
• CPC Class Codes: G01J 3/32 Investigating bands of a spectrum in sequence by a single detector
• CPC Class Codes: G01J 3/427 Dual wavelengths spectrometry
• CPC Class Codes: G01N 2021/151 Gas blown
• CPC Class Codes: G01N 2021/8411 Application to online plant, process monitoring
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/15 Preventing contamination of the components of the optical system or obstruction of the light path
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/85 Investigating moving fluids or granular solids
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

The present invention relates to a semiconductor processing system that employs infrared-based thermopile detector for process control, by analyzing a material of interest, based on absorption of infrared light at a characteristic wavelength by such material. Specifically, an infrared light beam is transmitted through a linear transmission path from an infrared light source through a sampling region containing material of interest into the thermopile detector. The linear transmission path reduces the risk of signal loss during transmission of the infrared light. The transmission path of the infrared light may comprise a highly smooth and reflective inner surface for minimizing such signal loss during transmission.

Claims

1. A detector system adapted for processing of a material therein, said system comprising:

a sampling region for the material, the material comprising a first gas;

an infrared radiation source constructed and arranged to transmit infrared radiation through the sampling region; and

a thermopile detector constructed and arranged to receive infrared radiation after the transmission thereof through the sampling region and to responsively generate an output signal correlative of said material within the sampling region;

wherein the infrared radiation is transmitted along a transmission path that is substantially linear, and wherein said infrared radiation source and said thermopile detector are aligned along the transmission path of said infrared radiation; and

wherein the system is characterized by any of the following;

(a) a process controller receives the output signal from the thermopile detector;

(b) a heating element distinct from said infrared radiation source is adapted to heat at least a portion of the transmission path;

(c) said transmission path comprises an inner surface characterized by a roughness in a range of from about 0.012 μ

m Ra to about 1.80 μ

m Ra; and

(d) at least one gas introduction element is arranged to introduce a second gas between the infrared radiation source and the thermopile detector.

2. The detector system of claim 1, wherein a process controller receives the output signal from the thermopile detector.

3. The detector system of claim 2, wherein the process controller comprises an integrated circuit board that is arranged in immediate signal receiving relationship with said thermopile detector for minimizing signal loss during signal transmission.

4. The detector system of claim 3, wherein said integrated circuit board is positioned adjacent to said thermopile detector.

5. The detector system of claim 1, wherein a heating element distinct from said infrared radiation source is adapted to heat at least a portion of the transmission path.

6. The detector system of claim 1, wherein said transmission path comprises an inner surface characterized by a roughness in a range of from about 0.012 μ

m Ra to about 1.80 μ

m Ra.

7. The detector system of claim 1, further comprising at least one gas introduction element arranged to introduce a second gas between said infrared radiation source and said thermopile detector.

8. A method of manufacturing a semiconductor device comprising operating a semiconductor process including processing of or with a material, and monitoring and/or controlling said process using the detector system of claim 1.

9. The system of claim 1, wherein said first gas comprises a process gas, and said second gas comprises a purge gas.

10. A detector system adapted for processing therein a material comprising a first gas, the system comprising:

a sampling region for the material, the sampling region defining a radiation transmission path;

an infrared radiation source constructed and arranged to emit infrared radiation into the sampling region; and

a thermopile detector constructed and arranged to receive at least a portion of said infrared radiation following passage thereof through the sampling region, and arranged to responsively generate an output signal correlative of said material;

wherein the system is further characterized by any of the following;

(a) at least one gas introduction element is arranged to introduce a second gas between the infrared radiation source and the thermopile detector;

(b) the radiation transmission path comprises an inner surface having a roughness in a range of from 0.012 μ

m Ra to 1.80 μ

m Ra; and

(c) a heating element distinct from the infrared radiation source is adapted to heat at least a portion of the radiation transmission path.

11. The detector system of claim 10, wherein said system includes at least one gas introduction element arranged to introduce a second gas between the infrared radiation source and the thermopile detector.

12. The detector system of claim 11, wherein said first gas comprises particles subject to being deposited in or on any of the infrared source, the sampling region, and the thermopile detector, and said at least one gas introduction element is adapted to reduce formation of or remove particles in or on any of the infrared source, the sampling region, and the thermopile detector.

13. The detector system of claim 11, wherein said at least one gas introduction element is adapted to introduce said second gas along a direction that is substantially perpendicular to the first gas flow.

14. The detector system of claim 11, wherein said at least one gas introduction element is adapted to introduce said second gas along a direction that is substantially parallel to the first gas flow.

15. The detector system of claim 11, wherein said at least one gas introduction element is adapted to generate one or more sheaths of second gas that encompass a flow of said material through the sampling region.

16. The detector system of claim 11, wherein said at least one gas introduction element comprises at least one porous medium through which said second gas flows.

17. The detector system of claim 11, wherein said first gas comprises a process gas, and said second gas comprises a purge gas.

18. The detector system of claim 10, wherein the radiation transmission path comprises an inner surface having a roughness in a range of from 0.012 μ

m Ra to 1.80 μ

m Ra.

19. The detector system of claim 18, wherein said an inner surface has a roughness in a range of from 0.10 μ

m Ra to 0.80 μ

m Ra.

20. The detector system of claim 18, wherein said inner surface has a reflectivity in a range of from 70% to 99%.

21. The detector system of claim 10, comprising a heating element distinct from the infrared radiation source and adapted to heat at least a portion of the radiation transmission path.

22. The detector system of claim 10, wherein said radiation transmission path is substantially linear, and wherein said infrared radiation source and said thermopile detector are aligned along opposing ends of said radiation transmission path.

23. The detector system of claim 10, wherein said sampling region is substantially isolated from said infrared radiation source and said thermopile detector.

24. The detector system of claim 10, communicatively coupled to receive said material from an upstream chemical vapor deposition chamber.

25. A method of operating a semiconductor process including processing of or with a material comprising a first gas, said method comprising emitting infrared radiation generated by an infrared radiation source into a sampling region defining a radiation transmission path and containing said material, receiving at least a portion of said emitted infrared radiation with a thermopile detector, generating an output from said thermopile detector indicative of presence or concentration of a desired component of said material, and controlling one or more conditions in and/or affecting the semiconductor process in response to said output, wherein the method is further characterized by any of the following:

(a) a second gas is flowed through at least one gas introduction element and introduced between the infrared radiation source and the thermopile detector;

(b) said infrared radiation is transmitted along a transmission path that comprises an inner surface characterized by a roughness in a range of from about 0.012 μ

m Ra to about 1.80 μ

m Ra; and

(c) at least a portion of said radiation transmission path is heated by a heating element that is distinct from the infrared radiation source.