Spectral feature control apparatus

Patent metadata

Field	Value
Publication number	US-10416471-B2
Application number	US-201615295280-A
Country	US
Kind code	B2
Filing date	Oct 17, 2016
Priority date	Oct 17, 2016
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A spectral feature selection apparatus includes a dispersive optical element arranged to interact with a pulsed light beam; three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and a pulsed optical source; and one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam. At least one of the actuation systems is a rapid actuation system that includes a rapid actuator configured to rotate its associated refractive optical element about a rotation axis. The rapid actuator includes a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element.

First claim

What is claimed is:

1. A spectral feature selection apparatus for a pulsed optical source that produces a pulsed light beam, the apparatus comprising:
a dispersive optical element arranged to interact with the pulsed light beam;
three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and the pulsed optical source;
one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam;
at least one of the actuation systems being a rapid actuation system that comprises a rapid actuator configured to rotate its associated refractive optical element about a rotation axis, the rapid actuator comprising a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element; and
a control system connected to the one or more actuation systems, the control system configured to send a signal to the rapid actuator to adjust the rotation shaft of the rotary stepper motor to thereby rotate the associated refractive optical element about its rotation axis.

2. The apparatus of claim 1 , wherein the rapid actuator is configured to rotate the refractive optical element that is farthest from the dispersive optical element.

3. The apparatus of claim 1 , wherein the pulsed light beam path lies in an XY plane of the apparatus, and the rotation shaft of the rotary stepper motor has an axis that is parallel with a Z axis of the apparatus to thereby rotate the associated refractive optical element about its rotation axis, which is parallel with the Z axis of the apparatus.

4. The apparatus of claim 3 , wherein the rapid actuation system also includes a secondary actuator physically coupled to the associated refractive optical element, the secondary actuator configured to rotate the associated refractive optical element about an axis that lies in the XY plane and also lies in the plane of a hypotenuse of the associated refractive optical element.

5. The apparatus of claim 1 , further comprising a position monitor that detects a position of the rotation shaft of the rotary stepper motor.

6. The apparatus of claim 5 , wherein the control system is connected to the position monitor, and is configured to receive the detected position of the rotation shaft and to adjust the rotation shaft if the received detected position is not within an acceptable range of positions.

7. The apparatus of claim 5 , wherein the position monitor is an optical rotary encoder.

8. The apparatus of claim 1 , wherein the rotation shaft is configured to rotate the refractive optical element associated with the rapid actuator about an offset axis that is offset from the rotation axis.

9. The apparatus of claim 1 , wherein the shaft axis is configured to rotate about 360° to thereby rotate the associated refractive optical element about 360°.

10. The apparatus of claim 1 , wherein the refractive optical element associated with the rapid actuator is fixedly coupled to the shaft axis.

11. The apparatus of claim 1 , wherein the control system comprises a rapid controller connected to the rotary stepper motor, the adjustment to the rotation shaft being performed by way of the rapid controller.

12. The apparatus of claim 1 , wherein the rotation of the refractive optical element associated with the rapid actuator causes a change in the pulsed light beam that interacts with the dispersive optical element, the change in the pulsed light beam causing a change in the bandwidth of the pulsed light beam, wherein a range of bandwidth due to the rotation of the refractive optical element associated with the rapid actuator is at least 250 femtometers (fm).

13. The apparatus of claim 12 , wherein the rotation of the refractive optical element associated with the rapid actuator by one unit of rotation of the rotation shaft causes the bandwidth of the pulsed light beam to change by an amount that is less than a resolution of a bandwidth measurement device that measures the bandwidth of the pulsed light beam.

14. The apparatus of claim 1 , wherein the dispersive optical element is a diffractive optical element arranged to interact with a pulsed light beam in a Littrow configuration so that the pulsed light beam diffracted from the diffractive optical element travels along the path of the pulsed light beam that is incident on the diffractive optical element.

15. The apparatus of claim 1 , wherein the refractive optical elements are right-angled prisms through which the pulsed light beam is transmitted so that the pulsed light beam changes its magnification as it passes through each right-angled prism, wherein the right-angled prism that is farthest from the dispersive optical element has the smallest hypotenuse of the plurality, and each consecutive right-angled prism closer to the dispersive optical element has a larger or same size hypotenuse than the adjacent right-angled prism that is farther from the dispersive optical element.

16. The apparatus of claim 1 , wherein the control system is configured to receive an instruction to adjust one or more spectral features of the pulsed light beam, and to send the signal to the rapid actuator to adjust the rotation shaft of the rotary stepper motor to rotate the associated refractive optical element about its rotation axis in response to the received instruction and while sending a signal to the pulsed optical source to produce the pulsed light beam.

17. The apparatus of claim 1 , wherein the control system is configured to send a signal to the rapid actuator to adjust the rotation shaft of the rotary stepper motor to rotate the associated refractive optical element about its rotation axis while sending a signal to the pulsed optical source to produce the pulsed light beam.

18. The apparatus of claim 1 , wherein the control system is in communication with a photolithography exposure apparatus that receives the pulsed light beam and the control system is configured to receive an instruction from the photolithography exposure apparatus to modify a spectral feature of the pulsed light beam while sending a signal to the pulsed optical source to produce the pulsed light beam.

19. The apparatus of claim 12 , wherein the rotation of the refractive optical element associated with the rapid actuator causes a change in the magnification of the pulsed light beam that interacts with the dispersive optical element.

20. A spectral feature selection apparatus for a pulsed optical source that produces a pulsed light beam, the apparatus comprising:
a dispersive optical element arranged to interact with the pulsed light beam;
a plurality of refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and the pulsed optical source;
a plurality of actuation systems, each actuation system being associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam;
at least one of the actuation systems comprising a rapid actuator that comprises a rotary motor having a rotational shaft that rotates about a shaft axis that is perpendicular to a plane of the apparatus;
wherein the refractive optical element associated with the rapid actuator is mounted to the rapid actuator so that the refractive optical element is

Assignees

• Cymer LLC

Inventors

• Mason Eric Anders

Classifications

• H10P76/2042

  using lasers · CPC title

• H01S3/2366

  comprising a gas as the active medium (H01S3/10092, H01S3/2383 take precedence) · CPC title

• H01S3/225

  comprising an excimer or exciplex · CPC title

• H01S3/08009

  using a diffraction grating · CPC title

• H01S3/08004

  incorporating a dispersive element, e.g. a prism for wavelength selection (H01S3/0811, H01S3/08022 take precedence) · CPC title