Anh T Ngo

US Patent:

6407546, Jun 18, 2002

Filed:

Apr 7, 2000

Appl. No.:

09/545119

Inventors:

Cuong Duy Le - Gilroy CA 95020
Anh The Ngo - San Jose CA 95132

International Classification:

G01B 706

US Classification:

324230, 324202, 324226, 324716, 324 711

Abstract:

A method and system for identifying thicknesses of inspection samples, such as semiconductor wafers is presented. The method and system includes a probe housing, comprising an eddy current sense coil and a linear motion controller, and a computer that controls the linear motion controller and the eddy current sense coil. The computer may be configured to identify a thickness of the inspection sample by a method comprising the generation of a natural intercepting curve based on resistance and reactance measurements of at least two data points. Then, a plurality of corresponding resistance and reactance measurements of a location on the inspection sample is obtained with the eddy current sensor, where the eddy current sensor makes a first measurement at a first distance from the inspection sample, and makes each of the remaining plurality of measurements at a distance that is incrementally further away from the inspection surface. Next, an inspection sample curve is generated based on the plurality of corresponding resistance and reactance measurements obtained from the inspection sample. An intersection point between the natural intercepting curve and the inspection sample curve is also generated.

Address:

657 Adagio Way, San Jose, CA 95111

Phone:

(408)7755331

VIN:

1HGCP3F89BA029941

Make:

HONDA

Model:

ACCORD

Year:

2011