Polarization control of pulsed light beam

Patent metadata

Field	Value
Publication number	US-9709897-B2
Application number	US-201514925641-A
Country	US
Kind code	B2
Filing date	Oct 28, 2015
Priority date	Oct 28, 2015
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A photolithography system includes an optical system, an actuation apparatus, and a control module. The optical system includes an optical source that produces a pulsed light beam traveling along a beam path; a plurality of optical components positioned between the optical source and a photolithography exposure apparatus, at least some of the plurality of optical components configured to receive the pulsed light beam and direct the pulsed light beam to the photolithography exposure apparatus; and an optical element positioned to interact with the pulsed light beam. The actuation apparatus is coupled to the optical element. The actuation apparatus is configured to adjust a physical property of the optical element based on a control signal from the control module to thereby adjust a polarization of the pulsed light beam.

First claim

What is claimed is:

1. A photolithography system comprising:
an optical system comprising:
an optical source that produces a pulsed light beam traveling along a beam path;
a plurality of optical components positioned between the optical source and a photolithography exposure apparatus, at least some of the plurality of optical components configured to receive the pulsed light beam and direct the pulsed light beam to the photolithography exposure apparatus; and
an optical element positioned to interact with the pulsed light beam;

an actuation apparatus coupled to the optical element, the actuation apparatus comprising a rotation mechanism to which the optical element is fixed, wherein the rotation mechanism is configured to adjust an angle of the optical element relative to an optical axis of the pulsed light beam based on a control signal to thereby adjust a polarization of the pulsed light beam; and
a control module connected to the photolithography exposure apparatus, the optical system, and the actuation apparatus, the control module configured to:
receive one or more parameters from one or more of the photolithography exposure apparatus and the optical system,
analyze the one or more parameters to determine whether any of the parameters is outside an acceptable range of target values; and
if the determination indicates that any of the parameters is outside the acceptable range of target values, send the control signal to the actuation apparatus to adjust the angle of the optical element to thereby alter the polarization of the pulsed light beam;

wherein the rotation mechanism either adjusts an angle of the optical element about a perpendicular element axis that is perpendicular to a first direction of polarization of the pulsed light beam or adjusts an angle of the optical element about a parallel element axis that is parallel with the first direction of polarization of the pulsed light beam.

2. The system of claim 1 , wherein the optical element comprises an at least partially-transmissive optical element.

3. The system of claim 2 , wherein the at least partially-transmissive optical element lacks an anti-reflective coating.

4. The system of claim 2 , wherein the at least partially-transmissive optical element directs the pulsed light beam through an optical pulse stretcher.

5. The system of claim 2 , wherein the at least partially-transmissive optical element is made of calcium fluoride.

6. The system of claim 2 , wherein the at least partially-transmissive optical element is made of a bulk material that transmits at least 90% of light having a wavelength that is between 100 nm and 400 nm.

7. The system of claim 1 , wherein the control module receives one or more parameters from one or more of the photolithography exposure apparatus and the optical system by receiving a measurement of the polarization of the pulsed light beam.

8. The system of claim 1 , wherein the control module is configured to determine the control signal based on a determined adjustment to the property of the pulsed light beam.

9. The system of claim 1 , wherein the optical element comprises a variable optical phase retarding element.

10. The system of claim 1 , wherein the optical element is between the optical source that produces a pulsed light beam and the plurality of optical components.

11. The system of claim 1 , wherein the optical source comprises a two-stage laser system that includes a master oscillator that provides a seed light beam to a power amplifier.

12. The system of claim 1 , wherein adjusting the angle of the optical element alters the polarization by adjusting a relative amount of light that is reflected from and transmitted through the optical element.

13. A photolithography method comprising:
supplying a pulsed light beam to a photolithography exposure apparatus, the supplying comprising:
producing, at an optical source, a pulsed light beam traveling along a beam path;
directing the produced pulsed light beam through a plurality of optical components positioned between the optical source and the photolithography exposure apparatus; and
interacting the pulsed light beam with an optical element;

receiving one or more parameters relating to the pulsed light beam or to the photolithography exposure apparatus;
determining whether any of the received one or more parameters is outside an acceptable range of target values for that parameter;
if it is determined that a received parameter is not within its acceptable range of target values, then determining an adjustment to a polarization of the pulsed light beam; and
adjusting an angle of the optical element relative to an optical axis of the pulsed light beam based on the determined adjustment to the pulsed light beam polarization to thereby alter the polarization of the pulsed light beam output from the optical element;
wherein adjusting the angle of the optical element relative to the optical axis comprises either adjusting the angle of the optical element about a perpendicular element axis that is perpendicular to a first direction of polarization of the pulsed light beam or adjusting the angle of the optical element relative to the optical axis comprises adjusting the angle of the optical element about a parallel element axis that is parallel with the first direction of polarization of the pulsed light beam.

14. The method of claim 13 , wherein adjusting the angle of the optical element to thereby alter the polarization of the pulsed light beam output from the optical element occurs while the pulsed light beam is being supplied to the photolithography exposure apparatus.

15. The method of claim 13 , wherein receiving one or more parameters comprises receiving a measurement of the polarization of the pulsed light beam.

16. The method of claim 13 , wherein adjusting the angle of the optical element alters the polarization of the pulsed light beam by adjusting a relative amount of light that is reflected from and transmitted through the optical element.

17. A method comprising:
supplying a pulsed light beam to a photolithography exposure apparatus, the supplying comprising:
producing, at an optical source, a pulsed light beam traveling along a beam path; and
interacting the pulsed light beam with an optical element on the beam path;

receiving one or more parameters relating to the pulsed light beam or to the photolithography exposure apparatus;
determining whether any of the received one or more parameters is outside an acceptable range of target values for that parameter; and
based on the determination, altering the polarization of the pulsed light beam by adjusting an amount of light that is reflected from the optical element relative to the amount of light that is transmitted through the optical element by adjusting an angle of the optical element about an axis perpendicular to an optical axis of the pulsed light beam,
wherein adjusting the angle of the optical element relative to the optical axis comprises either adjusting the angle of the optical element about a perpendicular element axis that is perpendicular to a first direction of polarization of the pulsed light beam or adjusting the angle of the optical element about a parallel element axis that is parallel with the first direction of polarization of the pulsed light beam.

18. The method of claim 17 , wherein adjusting the physical property of the optical element to thereby alter the polarization of the pulsed light beam output from the optical element occurs while the pulsed light beam is being supplied to the photolithograph

Assignees

• Cymer LLC

Inventors

• Mason Eric Anders
• Zurita Omar
• Rechtsteiner Gregory Allen
• Rafac Robert Jay
• Lalovic Ivan B

Classifications

• G03F7/70191 Primary

  Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like · CPC title

• G03F7/70041

  by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control · CPC title

• G03F7/70566

  Polarisation control · CPC title