Photocopying – Projection printing and copying cameras – Focus or magnification control
Reexamination Certificate
2005-05-13
2008-10-28
Lee, Diane I. (Department: 2851)
Photocopying
Projection printing and copying cameras
Focus or magnification control
C355S052000, C355S053000
Reexamination Certificate
active
07443484
ABSTRACT:
A method of focus variation is described herein to achieve a one-step exposure of a wafer without the limitation of applying a complex y-tilt to a wafer stage. The position of the wafer surface to be exposed is periodically varied with respect to the focal plane, or vice versa. This relative movement between the focal plane, or best focus position along the optical axis and the wafer stage, or the wafer surface, is achieved by applying a movement to at least one of the reticle stage, one or more of the optical elements of the projection lens, and the wafer stage. The frequency of the movement is selected in dependence of the laser frequency (upper limit) or the scanning frequency (lower limit).
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Nölscher Christoph
Tschischgale Joerg
Edell Shapiro & Finnan LLC
Infineon - Technologies AG
Lee Diane I.
Liu Chia-how Michael
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