Optics: measuring and testing – Inspection of flaws or impurities
Reexamination Certificate
2005-10-11
2005-10-11
Toatley, Jr., Gregory J. (Department: 2877)
Optics: measuring and testing
Inspection of flaws or impurities
C236S10100B, C250S492200
Reexamination Certificate
active
06954266
ABSTRACT:
A method for inspecting multilayer masks to detect any defects includes illuminating a pixel region on a mask to be inspected, using illuminating light having a peak wavelength that is close to that of light reflected by the mask. The illuminating light specularly reflected by the mask is blocked. Scattered reflected illuminating light is collected and used to form an enlarged image. An image detector having a large plurality of pixels is used to observe the enlarged image to detect whether there are defects on the mask. The method is implemented using an mask inspection apparatus including a plasma light source for generating radiant rays, an illuminating light collecting optical system that collects radiated light from the light source for enlarged image formation illumination of a subject inspection region, a Schwarzschild optical system including convex and concave mirrors for collecting scattered light from the subject inspection region and forming an enlarged image of the inspection region, an image detector having a large plurality of pixels for recording the enlarged image that is obtained, and an analyzer that analyzes the images obtained to determine whether there is a defect.
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Journal of Vacuum Science & Technology B, American Vacuum Society, Nov./Dec. 2000, vol. 18, No. 6.
National Institute of Advanced Industrial Science and Technology
Nguyen Sang H.
Toatley , Jr. Gregory J.
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