Mrs Technology, Inc.

Other

Azores Corporation

Craig R Simpson

J Casey Donaher

Robert A McEachern

David S Holbrook

Mark S Lucas

Roger McCleary

Marc S Lucas

Misalignment errors in a lithographic system resulting from the effect of environmental changes on the lens system itself are detected and corrected. A fiducial on the reticle adjacent to its working area is projected through the lens. A metrology plate carried by the lens holds reference mirrors and detectors. The reference mirrors receive the resultant image and reflect it to detectors in a reflected image plane. This provides feedback to the reticle alignment system as to the extent of misalignment, if any. Correction is made by moving the reticle until alignment is achieved and detected. This motion is achieved by using a reticle chuck with linear motors.

Reticle alignment system for use in lithography

A lithographic stage is carried by a platen formed of a plurality of tiles containing a uniformly spaced grid of teeth and having low reluctance and high resistivity. The teeth have been formed by powder metal technology using as powder particles of a ferromagnetic material, the particles being of high resistivity or coated with an insulating material. The space between the teeth is filled with non-magnetic material, such as epoxy, and the entire platen finished such that it has a smooth and uniform flat upper surface.

Platen for use with lithographic stages and method of making same

Two lithographic substrate stages are used in a single lithographic system. While a substrate on one stage is being exposed, a second substrate is being loaded, unloaded, or aligned on a second stage. After exposure, the first stage is unloaded, reloaded, and the newly-loaded substrate is aligned, while the second substrate on the second stage is being exposed. The two stages are thus used alternately in different steps of the process. One of the steps is being performed on one stage while a different step is being performed on the other stage. The substrates on both stages are, therefore, being acted upon simultaneously. The two stages are carried on a single linear motor platen, and moved about the platen by use of linear motors. The two stages alternately both move in clockwise directions about the platen, or both move in counterclockwise directions. When both move in clockwise directions, the first stage is moving to the exposure position, and the second stage is moving to the unload/load/align station. When they both move in counterclockwise directions, the second stage is moving to the exposure position and the first stage is moving to the unload/load/align station.

Lithography System using dual substrate stages

A direct reticle reference alignment system for use in photolithography for use with substrates having optical transmissivity. The system includes a movable stage (14), a transmissive substrate (11) held by the stage and bearing at least one plate mark (15) upon its upper surface, an optical system having a light source (1) for illuminating and projecting a reticle alignment image (4) upon the substrate (11) for alignment with the plate mark (15), a sensor (17) mounted in the stage (14) below the substrate (11) and the plate mark (15) to receive light from the projected alignment image (4), the sensor (17) producing an electrical signal related to the degree of alignment, and a stage control actuated by the signal to position the stage (14) and, so, align the substrate (11) with the reticle (4). The sensor (17) includes a light channel (19), such as a fiber optic rod, positioned to receive images from the lower surface (13) of said substrate ( 11) and carry them to the photocell. The detector may include a quadcell and a corresponding light channel for each cell in the quadcell.

Growing community of inventors

Danville, VT, United States of America

Craig R Simpson