Apparatus with optical cavity for determining process rate

Patent metadata

Field	Value
Publication number	US-10930478-B2
Application number	US-201815988411-A
Country	US
Kind code	B2
Filing date	May 24, 2018
Priority date	May 24, 2018
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

An apparatus for processing a substrate is provided. A processing chamber is provided. A substrate support is within the processing chamber. A gas inlet provides a process gas into the processing chamber. A gas source provides the process gas to the gas inlet. An exhaust pump pumps gas from the processing chamber. A parameter measurement system comprises a cavity ring down device in fluid communication with the processing chamber, comprising a first cavity ring down mirror on a first side of the cavity ring down device and a second cavity ring down mirror on a second side of the cavity ring down device spaced apart from the first cavity ring down mirror. At least one laser light source is optically coupled to the first cavity ring down mirror. A light detector is optically coupled to either the first cavity ring down mirror or the second cavity ring down mirror.

First claim

What is claimed is:

1. An apparatus for processing a substrate, comprising:
a processing chamber;
a substrate support within the processing chamber;
a gas inlet for providing a process gas into the processing chamber, wherein when a process is carried out to process the substrate in the processing chamber, the process provides a gas byproduct;
a gas source for providing the process gas to the gas inlet;
an exhaust pump for pumping the gas byproduct from the processing chamber; and
a parameter measurement system, comprising:
a cavity ring down device in fluid communication with the processing chamber, comprising:
a first cavity ring down mirror on a first side of the cavity ring down device; and
a second cavity ring down mirror on a second side of the cavity ring down device spaced apart from the first cavity ring down mirror;

at least one laser light source optically coupled to the first cavity ring down mirror; and
a light detector optically coupled to either the first cavity ring down mirror or the second cavity ring down mirror.

2. The apparatus, as recited in claim 1 , wherein the first cavity ring down mirror has a first surface on a first side of the first cavity ring down mirror and a second surface on a second side of the first cavity ring down mirror, wherein the second surface of the first cavity ring down mirror faces outside the cavity ring down device and the first surface of the first cavity ring down mirror faces inside the cavity ring down device, wherein the at least one laser light source is optically coupled to the second surface of the first cavity ring down mirror.

3. The apparatus as recited in claim 2 , wherein the second cavity ring down mirror has a first surface on a first side of the second cavity ring down mirror and a second surface on a second side of the second cavity ring down mirror, wherein the second surface of the second cavity ring down mirror faces outside the cavity ring down device and the first surface of the second cavity ring down mirror faces inside the cavity ring down device, wherein the light detector is optically coupled to the second surface of the first cavity ring down mirror or the second surface of the second cavity ring down mirror.

4. The apparatus as recited in claim 1 , wherein the first cavity ring down mirror and the second cavity ring down mirror each have a reflectivity to light from the at least one laser light source of at least 99.9% and transmission of light from the at least one laser light source of 0.1% to 0.001%.

5. The apparatus, as recited in claim 1 , further comprising one or more heaters for heating the first and second cavity ring down mirrors to a temperature of at least 120° C.; and wherein the first cavity ring down mirror and the second cavity ring down mirror are temperature compensated to operate at a temperature of at least 120° C.

6. The apparatus, as recited in claim 1 , wherein the at least one laser light source provides a first light beam at a first frequency and a second light beam at a second frequency that is different from the first frequency.

7. The apparatus, as recited in claim 1 , wherein the cavity ring down device is in fluid communication with the processing chamber by receiving the gas byproduct from the processing chamber via the exhaust pump.

8. The apparatus, as recited in claim 7 , wherein the parameter measurement system uses the gas byproduct and light generated by the at least one laser light source and reflected between the first and second cavity ring down mirrors to measure one or more process parameters and adjust the process based on the one or more process parameters.

9. The apparatus, as recited in claim 1 , wherein the cavity ring down device is in fluid communication with the processing chamber by receiving plasma from the processing chamber, the apparatus further comprising a valve for controlling flow of the plasma between the processing chamber and the cavity ring down device.

10. The apparatus, as recited in claim 9 , wherein the parameter measurement system uses the gas byproduct and light generated by the at least one laser light source and reflected between the first and second cavity ring down mirrors to measure one or more process parameters and adjust the process based on the one or more process parameters.

11. The apparatus, as recited in claim 1 , wherein the cavity ring down device is in fluid communication with the processing chamber in that a portion of an inner volume of the processing chamber is between the first cavity ring down mirror and the second cavity ring down mirror; and wherein the inner volume includes plasma that is present when the process is carried out.

12. The apparatus, as recited in claim 11 , wherein the parameter measurement system uses the gas byproduct and light generated by the at least one laser light source and reflected between the first and second cavity ring down mirrors to measure one or more process parameters and adjust the process based on the one or more process parameters.

13. The apparatus, as recited in claim 1 , wherein the first cavity ring down mirror is near confocal with the second cavity ring down mirror.

14. The apparatus as recited in claim 1 , wherein the first cavity ring down mirror and the second cavity ring down mirror have a reflectivity to light from the at least one laser light source of at least 99.99% and transmission of light from the at least one laser light source of 0.01% to 0.001%.

Assignees

• Lam Res Corp

Inventors

• Manne Jagadeeshwari
• Kabouzi Yassine
• Albarede Luc

Classifications

• H10P50/242

  of Group IV materials · CPC title

• H01J37/32458

  Vessel · CPC title

• H01J37/32935

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

• H01J37/32834

  Exhausting · CPC title

• H01J37/226

  Optical arrangements for illuminating the object; optical arrangements for collecting light from the object · CPC title