The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 16, 2002
Filed:
Jan. 18, 2000
Applicant:
Inventors:
Josephus J. M. Braat, Delft, NL;
Cornelis J. van der Laan, Maasluis, NL;
Assignee:
ASM Lithography B.V., Veldhoven, NL;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B 2/768 ; G03B 2/700 ; G03B 2/732 ; G03B 2/100 ; G01B 1/102 ;
U.S. Cl.
CPC ...
G03B 2/768 ; G03B 2/700 ; G03B 2/732 ; G03B 2/100 ; G01B 1/102 ;
Abstract
A plate with substantially constant thickness is used to compensate for the residual distortion in the image projected by a high-quality projection lens for lithography. The two surfaces of the plate have an identical aspherical profile, whose shape has been calculated using the measured distortion map of the lithographic objective. The figuring process applied to the plate uses the principle of polishing in the presence of an elastic deformation, so as to achieve the desired aspherical shape on both sides.