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:
Mar. 27, 2001
Filed:
Jul. 13, 1998
Erik R. Loopstra, Heeze, NL;
ASM Lithography B.V., Veldhoven, NL;
Abstract
In a lithographic projection apparatus, a time-saving height measurement method is used. While in a projection station (,) the pattern of a mask (,) is projected on the fields of a first substrate (,), the height of the fields of a second substrate (,) is measured in a measuring station (,). In the measuring station, the height of the substrate fields and the height of the substrate holder (,) are measured by a first height sensor (,) and a second height sensor (,), respectively, and the value of the height of the substrate holder associated with the ideal height of the substrate field is determined for each substrate field. In the projection station, only the height of the substrate holder (,) is controlled by a third height sensor (,). The second and third height sensors are preferably part of a composite XY interferometer system extended with a Z measuring axis.