William C Schluchter

US Patent:

7251039, Jul 31, 2007

Filed:

Apr 29, 2005

Appl. No.:

11/118949

Inventors:

William Clay Schluchter - Los Altos CA, US
Robert Todd Belt - Mountain View CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 9/02

US Classification:

356487, 356491

Abstract:

An interferometer is provided that minimizes the introduction of non-linear errors into displacement measurements. In one embodiment, non-linear errors are reduced by isolating reference and measurement beams over most of their respective optical paths leading to the detector, and by employing a separate amplitude-splitting non-polarizing optical beam splitter for each beam input into the interferometer. Additionally, the interferometer is scalable to an arbitrary number of optical axes or inputs.

US Patent:

7355719, Apr 8, 2008

Filed:

Aug 16, 2005

Appl. No.:

11/205368

Inventors:

William Clay Schluchter - Los Altos CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 9/02
G01B 11/02

US Classification:

356493, 356498, 356500

Abstract:

An interferometer provides a large dynamic range for perpendicular displacement measurements. In operation, a measurement reflector on an object reflects a measurement beam to an overlying Porro prism, and a reference reflector on the object returns a reference beam to the interferometer. A second Porro prism in the interferometer can return the reference beam for a second pass to the reference reflector, while the measurement beam complete only one pass. Reductions in beam walk-off result from retroreflections in the Porro prisms and the matching effects that some object rotations have on measurement and reference beams. Perpendicular motion of the object relative to the first Porro prism causes a Doppler shift only in the measurement beam. Accordingly, a beat frequency found when combining the measurement and reference beams can indicate a residual Doppler shift associated with the motion in the perpendicular direction.

US Patent:

7545507, Jun 9, 2009

Filed:

Mar 15, 2007

Appl. No.:

11/686855

Inventors:

William Clay Schluchter - Los Altos CA, US
Miao Zhu - San Jose CA, US
Geraint Owen - Palo Alto CA, US
Alan B. Ray - Palo Alto CA, US
Carol J. Courville - San Jose CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 11/02

US Classification:

356499

Abstract:

A displacement measurement apparatus includes a light source, a splitter grating, a measurement grating, and first a second detector arrays. The splitter grating splits a light beam into first and second measurement channels that each illuminates the measurement grating. The first and second measurement channels split into 0and 1order diffraction products at the measurement grating in a first pass and recombine at the measurement grating in a second pass before being measured at the first and second detector arrays.

US Patent:

7561280, Jul 14, 2009

Filed:

Jul 14, 2008

Appl. No.:

12/172810

Inventors:

William Clay Schluchter - Los Altos CA, US
Miao Zhu - San Jose CA, US
Alan B. Ray - Palo Alto CA, US
Gerry Owen - Palo Alto CA, US
Carol Courville - San Jose CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 11/02

US Classification:

356499

Abstract:

A sensor head for use with a measurement grating is described. The sensor head comprises: a splitter grating configured to split a light beam into first and second measurement beams; a first retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating; and a second retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating. In one embodiment the second measurement beam is diffracted by the measurement grating to form first and second sub-beams and one of the first and second sub-beams comprises a zeroth order diffraction component and a first order diffraction component. In another embodiment, the first and second sub-beams each comprise a zeroth order diffraction component and a first order diffraction component.

US Patent:

7924433, Apr 12, 2011

Filed:

Sep 8, 2008

Appl. No.:

12/206637

Inventors:

William Clay Schluchter - Santa Clara CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 11/02
G01B 9/02
G01D 5/36

US Classification:

356499, 356521, 250237 G

Abstract:

A measurement displacement system and method are described. The measurement displacement system comprises a sensor head configured to transmit input optical beams and to receive measurement beams. The system comprises a transmission grating configured to diffract the input optical beams into sub-beams comprising more than one diffraction order. The transmission grating is adapted move in a direction. The measurement displacement system comprises a reflective element configured to diffract the sub-beams from the transmission grating and to return the sub-beams to the transmission grating. The reflective element is substantially stationary relative to the sensor head and the transmission grating selectively recombines the sub-beams to form the measurement beams and returns the measurement beams to the sensor head.

US Patent:

7362447, Apr 22, 2008

Filed:

Dec 9, 2005

Appl. No.:

11/297968

Inventors:

William Clay Schluchter - Los Altos CA, US

Assignee:

Agilent Technologies, Inc. - Santa Clara CA

International Classification:

G01B 11/02

US Classification:

356500

Abstract:

An interferometer can achieve a high dynamic range for measurements along vertical and horizontal directions using a first measurement channel providing a high dynamic range measurement of a path including components respectively parallel and perpendicular to the optics-object separation and a second measurement channel providing a high dynamic range measurement with just a perpendicular component. Further, using the same techniques at multiple locations around permits a high dynamic range for measurements of the degrees of freedom of an object.

US Patent:

20050175217, Aug 11, 2005

Filed:

Feb 5, 2004

Appl. No.:

10/773794

Inventors:

Louis Mueller - Palo Alto CA, US
David Chu - Palo Alto CA, US
Michael Brosnan - Fremont CA, US
William Schluchter - Los Altos CA, US
Jeffrey Young - Campbell CA, US
Alan Ray - Palo Alto CA, US
Douglas Woolverton - Mountain View CA, US

International Classification:

G06K009/00

US Classification:

382103000

Abstract:

The position of a stage is determined. Images of a plurality of targets located on the stage are captured. The captured images of the plurality of targets are compared with stored images to determine displacement coordinates for each target. The displacement coordinates for the targets are translated into position coordinates for the stage.

US Patent:

20050185193, Aug 25, 2005

Filed:

Feb 20, 2004

Appl. No.:

10/783199

Inventors:

William Schluchter - Los Altos CA, US
Louis Mueller - Palo Alto CA, US
Douglas Woolverton - Mountain View CA, US
Jeffrey Young - Campbell CA, US
Alan Ray - Palo Alto CA, US
David Chu - Palo Alto CA, US

International Classification:

G01B009/02

US Classification:

356498000

Abstract:

A system and method for acquiring position information of a movable apparatus relevant to a specific axis is disclosed. In one embodiment, an interferometer generates first and second beams and various beam-steering members are located to define beam path segments for the two beams, but no beam path segment varies in length in unity with displacements of the movable apparatus along the specific axis. In another or the same embodiment, each beam path segment in which the first beam either impinges or has been reflected from the movable apparatus is symmetrical to a corresponding beam path segment of the second beam. The movable apparatus may be a wafer stage in which the “specific axis” is the exposure axis of a projection lens, but with all optical members which cooperate with the stage being located beyond the ranges of the wafer stage in directions perpendicular to the lithographic exposure axis.