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:
Oct. 09, 2001
Filed:
Dec. 09, 1999
Lee H. Veneklasen, Castro Valley, CA (US);
Etec Systems, Inc., Hayward, CA (US);
Abstract
A vacuum seal facilitates the production of a vacuum with a localized region on the surface of a substrate, such as a semiconductor wafer or reticle, which is subject to electron beam lithography. The vacuum seal permits vacuum processing in a localized region while allowing the remainder of the substrate and its supporting stage to be outside the vacuum. In addition to conventional concentric differential pumping of vacuum zones to provide adequate vacuum, additional differential pumping is provided in the vertical direction where a lower vacuum level is maintained immediately above the substrate. Also, an isolation valve is provided between the high vacuum of the electron beam column and the lesser vacuum immediately above substrate. This valve allows isolation of the high vacuum surrounding the beam during times when the gap between an edge of the substrate and its coplanar carrier surface are directly under the vacuum seal. This protects the high vacuum during substrate loading and unloading.