Large-area, high-throughput, high-resolution projection imaging system

  • US 5,285,236 A
  • Filed: 09/30/1992
  • Issued: 02/08/1994
  • Est. Priority Date: 09/30/1992
  • Status: Expired due to Term
First Claim
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1. A large-area, high-throughput, high-resolution, scan-and-repeat projection imaging system for replicating patterns present on a mask onto a substrate, characterized by(a) a stage subsystem (11/12) comprising mask locking means and substrate locking means providing fixed juxtaposition of the mask (14) relative to the substrate (10);

  • said stage subsystem being capable of scanning in one dimension, and when not scanning in that dimension, capable of moving laterally in a direction perpendicular to the scan direction so as to position itself for another scan;

    said stage subsystem thus being capable of exposing the full substrate by breaking up the substrate area into a certain number of parallel strips, and exposing each of said strips by scanning the length of the strip across a fixed illumination region;

    (b) an illumination subsystem (18) having the wavelength and intensity distribution characteristics suited for exposure of said substrate (10), having an effective source plane of a predetermined shape, and capable of illuminating on said mask (14) a region of said predetermined shape;

    (c) a projection subsystem (26,27/30) for imaging said illuminated region of said predetermined shape on the mask onto the substrate, having an object-to-image magnification ratio of unity, having the desired imaging resolution, having means (27/33) to render the image in the same orientation as the object, and having an image field of said predetermined shape and of an area smaller than the substrate area; and

    (d) control means to operatively interrelate said stage subsystem (11/12), said illumination subsystem (18) and said projection subsystem (26,27/30) to provide additive illumination in certain overlap regions of areas exposed by adjacent scans such that the effect of the exposure dose delivered in said overlap regions is seamless and the effect of the exposure dose delivered across the entire substrate is uniform.

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