Adjustable achromatic collimator assembly for endpoint detection systems

Patent metadata

Field	Value
Publication number	US-11719952-B2
Application number	US-202016947639-A
Country	US
Kind code	B2
Filing date	Aug 11, 2020
Priority date	Aug 11, 2020
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

Implementations disclosed describe a collimator assembly having a collimator housing that includes an interface configured to optically couple to a process chamber that has a target surface, and a port to receive an optical fiber to deliver, to an enclosure formed by the collimator housing, a first (second) plurality of spectral components of light belonging to a first (second) range of wavelengths, and an achromatic lens located, at least partially, within the enclosure formed by the collimator housing, the achromatic lens to direct the first (second) plurality of spectral components of light onto the target surface to illuminate a first (second) region on the target surface, wherein the second region is substantially the same as the first region.

First claim

What is claimed is:

1. A collimator assembly comprising:
a collimator housing comprising:
an interface configured to optically couple to a process chamber that has a target surface; and
a port to receive a first optical fiber, wherein the first optical fiber is to deliver, to an enclosure formed by the collimator housing, a first plurality of spectral components of light belonging to a first range of wavelengths and a second plurality of spectral components of light belonging to a second range of wavelengths, wherein the first range is within a 400-700 nm interval of wavelengths and the second range is outside the 400-700 nm interval of wavelength; and

an achromatic lens located, at least partially; within the enclosure formed by the collimator housing, the achromatic lens to:
direct the first plurality of spectral components of light onto the target surface to illuminate a first region on the target surface; and
direct the second plurality of spectral components of light onto the target surface to illuminate a second region on the target surface, wherein the second region is substantially the same as the first region.

2. The collimator assembly of claim 1 , wherein for the second region to be substantially the same as the first region, an overlap between the second region and the first region is to be at least 90% of each of the first region and the second region.

3. The collimator assembly of claim 1 , wherein for the second region to be substantially the same as the first region, an overlap between the second region and the first region is to be at least 95% of each of the first region and the second region.

4. The collimator assembly of claim 1 , wherein the port of the collimator housing is further to receive a second optical fiber, wherein the second optical fiber is to:
collect a first plurality of reflected, from the target surface, spectral components of light produced by the first plurality of spectral components of light directed onto the target surface;
collect a second plurality of reflected, from the target surface, spectral components of light produced by the second plurality of spectral components of light directed onto the target surface; and
deliver the first plurality of reflected spectral components of light and the second plurality of reflected spectral components of light to a light detector.

5. The collimator assembly of claim 4 , further a conduit to provide access of the first optical fiber and the second optical fiber to the enclosure formed by the collimator housing.

6. The collimator assembly of claim 1 , wherein the achromatic lens is frictionally held within the enclosure formed by the collimator housing.

7. The collimator assembly of claim 1 , wherein the achromatic lens is a triplet lens.

8. The collimator assembly of claim 1 , wherein the first plurality of spectral components alight directed onto the target surface by the achromatic lens forms a collimated beam.

9. The collimator assembly of claim 1 , further comprising an optically transparent filler that fills at least a part of the enclosure formed by the collimator housing.

10. The collimator assembly of claim 1 , wherein each of the first range of wavelengths and the second range of wavelengths is at least 100 nm wide, and wherein a center of the first range and a center of the second range are separated by at least 200 nm.

11. The collimator assembly of claim 1 , wherein the first optical fiber is further to deliver, to the enclosure formed by the collimator housing, a third plurality of spectral components of light belonging to a third range of wavelengths, wherein the achromatic lens is further to direct the third plurality of spectral components of light onto the target surface to illuminate a third region on the target surface, and wherein the third region is substantially the same as the first region, and wherein the third range of wavelengths is outside the 400-700 nm interval of wavelengths and is different from the second range.

12. The collimator assembly of claim 1 , wherein the collimator housing further comprises a tilt adjustment mechanism to modify alignment of an axis of the collimator housing relative to the process chamber.

13. The collimator assembly of claim 12 , wherein modified alignment of the axis of the collimator housing causes the first region and the second region to move relative to the target surface.

14. The collimator assembly of claim 12 , wherein the tilt adjustment mechanism comprises a plurality of adjustment screws, wherein adjustment of each of the plurality of adjustment screws modifies alignment of the axis of the collimator housing.

15. The collimator assembly of claim 14 , further comprising a first support rigidly coupled to the collimator housing, a second support rigidly coupled to the process chamber, and a gap between the first support and the second support, wherein the gap is to accommodate a motion of the first support caused by modified alignment of the axis of the collimator housing.

16. The collimator assembly of claim 15 , further comprising one or more tension springs to stabilize the first support relative to the second support.

17. The collimator assembly of claim 1 , wherein the target surface is a surface of one of a process chamber calibration device or a substrate that is being processed in the process chamber.

18. An endpoint detection system comprising:
a source of light to output a first plurality of spectral components of light belonging to a first range of wavelengths and a second plurality of spectral components of light belonging to a second range of wavelengths;
a collimator housing comprising:
an interface configured to optically couple to a process chamber that has a target surface; and
a port to receive a first optical fiber, wherein the first optical fiber is to deliver, to an enclosure formed by the collimator housing, the first plurality of spectral components of light belonging to a first range of wavelengths and the second plurality of spectral components of light belonging to a second range of wavelengths, wherein the first range is within a 400-700 nm interval of wavelengths and the second range is outside the 400-700 nm interval of wavelength;

an achromatic lens located, at least partially, within the enclosure formed by the collimator housing, the achromatic lens to:
direct the first plurality of spectral components of light onto the target surface to illuminate a first region on the target surface; and
direct the second plurality of spectral components of light onto the target surface to illuminate a second region on the target surface, wherein the second region is substantially the same as the first region;

a second optical fiber to:
collect a first plurality of reflected, from the target surface, spectral components of light produced by the first plurality of spectral components of light directed onto the target surface; and
collect a second plurality of reflected, from the target surface, spectral components of light produced by the second plurality of spectral components of light directed onto the target surface;
a light detector to receive, via the second optical fiber, the first plurality of reflected spectral components of light and the second plurality of reflected spectral components of light; and
a processing device, communicatively coupled to the light detector, to determine reflectance of the target surface, based on the received first plurality of reflected spectral components of light and the received second plurality of reflected spectral components of ligh

Assignees

• Applied Materials Inc

Inventors

• Han Pengyu
• O'Malley John Anthony
• Grimbergen Michael N
• Lian Lei
• Ummethala Upendra
• Kutney Michael

Classifications

• G02B27/30 Primary

  Collimators · CPC title

• G02B9/12

  having three components only · CPC title

• G02B27/005

  for correction of secondary colour or higher-order chromatic aberrations · CPC title

• G02B7/004

  Manual alignment, e.g. micromanipulators · CPC title