Controlled fluid flow for cleaning an optical element

Patent metadata

Field	Value
Publication number	US-10232413-B2
Application number	US-201715690707-A
Country	US
Kind code	B2
Filing date	Aug 30, 2017
Priority date	Aug 6, 2015
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

A fluid is directed toward a surface of an optical element based on a first flow pattern, the surface of the optical element including debris and the fluid directed based on the first flow pattern moving at least some of the debris to a first stagnation region at the surface of the optical element; and the fluid is directed toward the optical element based on a second flow pattern, the fluid directed based on the second flow pattern moving at least some of the debris to a second stagnation region on the surface of the optical element, the second stagnation region and the first stagnation region being different locations at the surface of the optical element. Directing the fluid toward the surface of the optical element based on the second flow pattern removes at least some of the debris from the first stagnation region.

First claim

What is claimed is:

1. A system comprising:
a conduit comprising a sidewall, the sidewall comprising at least one opening that passes from an interior of the conduit to an exterior of the conduit, the conduit configured to transport free radicals in the interior of the conduit and to pass the free radicals through the at least one opening that passes through the sidewall; and
a control system comprising an electronic storage coupled to one or more electronic processors, the electronic storage comprising instructions that, when executed, cause the one or more electronic processors to:
select a flow pattern from a plurality of flow patterns stored on the electronic storage, the flow patterns comprising free radical flow patterns, each of the free radical flow patterns comprising information sufficient to describe a flow of the free radicals through the at least one opening, the information sufficient to describe the flow of the free radicals through the at least one opening comprising at least a flow rate of the free radicals over a time period, and
apply the selected flow pattern to a flow controller of the system to cause the free radicals to pass through the at least one opening at a flow rate for the time period indicated by the selected flow pattern, wherein
the flow patterns further comprise gas flow patterns, the gas flow patterns including information sufficient to describe a flow of gas, the gas flowing in the system separately from the conduit, and the information sufficient to describe the flow of the gas comprising a flow rate of the gas over a gas time period, and
the instructions further comprise instructions that, when executed, cause the one or more processors to apply the selected gas flow pattern to the flow controller of the system to cause the gas to flow in the system at a gas flow rate for a gas time period indicated by the selected gas flow pattern.

2. The system of claim 1 , wherein the conduit is configured for placement relative to an optical element in a vacuum chamber of an extreme ultraviolet (EUV) light source.

3. The system of claim 2 , wherein the optical element comprises a collector mirror, the collector mirror comprising an aperture, the selected flow pattern comprises a free radical flow pattern and a gas flow pattern, and applying the selected gas flow pattern to the flow controller of the system causes the gas to flow through the aperture of the collector mirror at the gas flow rate and during the gas time period indicated by the selected gas flow pattern.

4. The system of claim 3 , wherein:
the conduit comprises at least two curved portions, the curved portions having a curvature that follows a perimeter of the collector mirror,
the selected free radical flow pattern describes the flow of free radicals through each of the at least two curved portions,
applying the selected gas flow pattern causes the gas to flow through the aperture of the mirror, and around a perimeter of the mirror, and
applying the selected free radical flow pattern causes the free radicals to flow from at least one of the at least two curved portions.

5. The system of claim 1 , wherein the conduit comprises a first conduit and a second conduit, each of the first conduit and the second conduit comprising a sidewall, the first conduit comprising a main branch, a first branch, and a second branch, the first branch and the second branch being in fluid communication with the main branch, and the first branch and the second branch being shaped for positioning along first and second portions of a perimeter of an optical element, the first and second portions being different portions of the perimeter of the optical element, and the second conduit comprises a curved sidewall shaped for positioning along a third portion of the perimeter of the optical element, the third portion being different than the first and second portions.

6. The system of claim 1 , wherein the controller is further configured to move the conduit relative to the optical element.

7. A method comprising:
accessing a first flow pattern, the first flow pattern comprising information sufficient to describe a flow of free radicals and a gas relative to an optical element;
directing the free radicals toward the optical element based on the first flow pattern, the free radicals being directed through a plurality of paths and at different flow rates in at least two of the paths; and
directing the gas toward the optical element based on the first flow pattern, the gas being directed along a path that is different from any of the paths along which the free radicals are directed.

8. The method of claim 7 , further comprising:
accessing a second flow pattern, the second flow pattern comprising information sufficient to describe a flow of free radicals and a gas relative to an optical element, and the second flow pattern having at least one aspect that is different from the first flow pattern;
directing the free radicals toward the optical element based on the second flow pattern; and
directing the gas toward the optical element based on the second flow pattern.

9. The method of claim 8 , wherein the at least one aspect comprises a flow rate.

10. A system for an extreme ultraviolet (EUV) light source, the system comprising:
a fluid transport system comprising:
at least a first conduit and a second conduit, the first conduit being configured to receive free radicals and gas from a first supply, and the second conduit being configured to receive free radicals and gas from a second supply, the first conduit comprising a sidewall that defines an interior space configured to transport free radicals and gas from the first supply, and the second conduit comprising a side wall that defines an interior space configured to transport free radicals and gas from the second supply, the sidewalls of the first conduit and the second conduit defining at least one opening that passes from the interior space of the respective conduit to an exterior of the respective conduit, the at least one opening being configured to pass free radicals and gas, wherein
the first conduit comprises a main branch, a first branch, and a second branch, the first branch and the second branch being in fluid communication with the main branch and the first supply, each of the first branch and the second branch being positionable to follow different portions of a perimeter of an optical element in a vacuum chamber of the EUV light source, and
the second conduit is positionable to follow a different portion of the perimeter of the optical element than the first branch and the second branch of the first conduit; and

a control system configured to control the transport of free radicals and gas in the first conduit and the second conduit.

11. The system of claim 10 , further comprising a flow controller, and wherein the control system is configured to:
select a flow pattern from a plurality of flow patterns, each of the flow patterns comprising information sufficient to describe a flow of the free radicals through the openings of the first conduit and the second conduit, the information sufficient to describe the flow of the free radicals through the at least one opening comprising at least a flow rate of the free radicals over a time period, and
apply the selected flow pattern to the flow controller to cause the free radicals to pass through the at least one opening at a flow rate for the time period indicated by the selected flow pattern.

12. The system of claim 11 , wherein
the flow patterns further comprise gas flow patterns, the gas flow patterns including information sufficient to describe a flow of gas, the gas flowing in the system separ

Assignees

• Asml Netherlands Bv

Inventors

• De Dea Silvia
• Xia Chunguang
• Wilson Gregory James
• Verhoff Brandon Wilson

Classifications

• G03F7/70925 Primary

  Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning · CPC title

• G01F1/00

  Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow (measuring a proportion of the volume flow G01F5/00) · CPC title

• B08B5/02 Primary

  Cleaning by the force of jets, e.g. blowing-out cavities {(airguns or nozzles per se B05B1/005)} · CPC title

• G03F7/70933

  Purge, e.g. exchanging fluid or gas to remove pollutants · CPC title