Title:
NON-CONTACT MEASURING METHOD FOR DIMENSION BY AUTOMATIC FOCUS OF LASER
Document Type and Number:
Japanese Patent JP3180091
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To enable high-precision measurement which is hardly influenced by the color and shape of a plane to be measured, by scanning a substance to be measured in X Y directions with a laser beam focusing it automatically, and detecting an edge by height information from a reference plane.
SOLUTION: A non-contact dimension measurement is performed by using a laser irradiation apparatus 4 having a semiconductor laser L, an objective lens 8 which moves upwards and downwards in accordance with a detection result of a light position detector 10, etc., for example. First, a measuring start point S in a reference plane M of a substance to be measured 1 is focused, and its Z value is made zero. Focusing it automatically the substance to be measured 1 is moved by an arbitrary measuring pitch. The X Y coordinate values of a point where the difference between its focused-time height and the height of the reference plane becomes a thresholde value ΔZ or more are taken in as edge data, and specified measurement is performed. Laser automatic focus is capable of following even a slight return light, and operates at a high speed. Since it is possible to condense a laser beam up to an extent of 1 μm for example, its positioning precision is also high.
Inventors:
Katsushige Nakamura
Katsuhiro Miura
Katsuhiro Miura
Application Number:
JP31487998A
Publication Date:
June 25, 2001
Filing Date:
November 05, 1998
Export Citation:
Assignee:
Mitaka Koki Co., Ltd.
International Classes:
G01B11/02; G01B11/08; G01B11/12; G03B13/36; (IPC1-7): G01B11/02
Domestic Patent References:
| JP631907A | ||||
| JP61235706A | ||||
| JP8178623A |