(54) DUAL STAGE DEFECT REGION IDENTIFICATION AND DEFECT DETECTION METHOD AND APPARATUS
(75) Inventor: Zongqiang Yu, Santa Clara, CA (US)
(73) Assignee: KLA-Tencor Technologies Corp.,
Milpitas, CA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
This patent is subject to a terminal disclaimer.
(21) Appl.No.: 11/974,033
(22) Filed: Oct. 10, 2007
(65) Prior Publication Data
US 2008/0106740 Al May 8, 2008
Related U.S. Application Data
(63) Continuation of application No. 11/430,681, filed on May 8, 2006, now Pat. No. 7,295,301, which is a continuation of application No. 11/046,493, filed on Jan. 28, 2005, now Pat. No. 7,046,355, which is a continuation of application No. 10/191,765, filed on Jul. 9, 2002, now Pat. No. 6,850,321.
(51) Int. CI.
G01N 21/88 (2006.01)
(52) U.S. CI 356/237.2; 356/237.4; 356/237.5;
(58) Field of Classification Search ... 356/237.1 237.6, 356/239.1-239.3, 239.7-239.8, 394; 382/144-151, 382/154; 73/1.01,1.89; 706/15-16,23,
See application file for complete search history.
A method and apparatus for inspecting patterned substrates, such as photomasks, for unwanted particles and features occurring on the transmissive as well as pattern defects. A transmissive substrate is illuminated by a laser through an optical system comprised of a laser scanning system, individual transmitted and reflected light collection optics and detectors collect and generate signals representative of the light transmitted and reflected by the substrate. The defect identification of the substrate is performed using transmitted and reflected light signals from a baseline comparison between two specimens, or one specimen and a database representation, to form a calibration pixelated training set including a non-defective region. This calibration pixilated training set is compared to a transmitted-reflected plot map of the subject specimen to assess surface quality.
25 Claims, 9 Drawing Sheets