PHONG NGUYEN
Pharmacy at 112 Ct, Vancouver, WA

6346986, Feb 12, 2002

Mar 14, 2000

09/524999

Phong T. Nguyen - Vancouver WA

Wafertech, Inc. - Camas WA

G01B 1124

356601, 356609, 250205, 25055945, 25055946, 25055947

A method to monitor a dimension of a pellicle includes projecting a first light signal against a surface of the pellicle. A second light signal reflected from the surface of the pellicle is detected, with the second light signal being a representation of the first light signal. The method determines if the dimension of the pellicle is within an allowable value based on a characteristic of the detected second light signal. The characteristic of the detected second light signal can include time periods between pulses of the detected second light signal, an intensity of the detected second light signal, or a positional displacement of the detected second light signal.

6459491, Oct 1, 2002

Jul 12, 2001

09/904870

Phong T. Nguyen - Vancouver WA

Wafer Tech - Camas WA

G01N 2100

356604, 3562371

A method to monitor a dimension of a pellicle includes projecting a first light signal against a surface of the pellicle. A second light signal reflected from the surface of the pellicle is detected, with the second light signal being a representation of the first light signal. The method determines if the dimension of the pellicle is within an allowable value based on a characteristic of the detected second light signal. The characteristic of the detected second light signal can include time periods between pulses of the detected second light signal, an intensity of the detected second light signal, or a positional displacement of the detected second light signal.

6778285, Aug 17, 2004

Jan 21, 2000

09/489461

Phong Nguyen - Vancouver WA
Ming-Chun Chou - Vancouver WA
Marvin Mills - Washougal WA

Wafertech, Inc. - Camas WA

G01C 1112

356630

A method for measuring a thickness of a photolithography element, such as a pellicle, includes projecting a light beam from a first side of the pellicle and at a plane above a first surface of the pellicle, projecting the light beam from the first side of the pellicle and at a plane corresponding to a plane of the pellicle, and projecting the light beam from the first side of the pellicle and at a plane below a second surface of the pellicle. The light beam can be projected from a laser light source. The light beams are projected at different media above and below the pellicle. The light beams pass through the first side of the different media and exit at a second side opposite to the first side at different intensities. The light beam may not pass through the pellicle if the light beam is incident to an opaque pellicle frame, and thus has minimal intensity at the second side. The resulting intensity of the projected light beams is detected at the second side by a detector, and an index corresponding to each detected resulting intensity is generated.

7142314, Nov 28, 2006

Nov 19, 2003

10/716814

Phong T. Nguyen - Vancouver WA, US
Stephen L. Hill - Vanvouver WA, US
Nadja Orlova - Vancouver WA, US

Wafertech, LLC - Camas WA

G01B 11/14

356620

A method of calibrating a positioning stage includes placing a substrate on the positioning stage. The substrate has a contrast film above a portion of the substrate. At least one pattern is at a predetermined location above the substrate, corresponding to a predetermined location on the positioning stage if the positioning stage has zero offset from a registration position. A beam is applied to a position where the pattern on the substrate would be located if the positioning stage has zero offset. At least one of the group consisting of reflected, transmitted and scattered portions of the beam is measured. Whether the positioning stage has a non-zero offset is detected based on the measured portion of the beam.