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Maskless lithography

  • US 5,870,176 A
  • Filed: 06/18/1997
  • Issued: 02/09/1999
  • Est. Priority Date: 06/19/1996
  • Status: Expired due to Term
First Claim
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1. A mask for scanning projection lithography, comprising:

  • a) a two-dimensional array of individually addressable micromirrors, each said micromirror comprising a plurality of moveable substrates having a reflecting surface, said reflecting surfaces for reflecting light from a light source into an imaging means entrance pupil, said reflecting surfaces modified by coating said surfaces with a non-reflecting coating and etching away only a portion of said non-reflective coating, thereby providing said reflecting surfaces with features for substantially eliminating coherence and diffraction effects in said reflected light, said features comprising;

    i) a reflecting surface having a shape consisting essentially of an octagon having regular trapezoidal projections laying at every other side of said octagon and wherein the wider base of each of said trapezoidal projections is contiguous with said octagon,ii) a reflecting surface having a size which is about one-half of a center-to-center distance between adjacent micromirrors; and

    iii) a reflecting surface have an edge which includes a plurality of phase reversed features and small light attenuating features along said edge;

    said light reflected by each of said micromirrors comprising a pixel having a light distribution profile, said reflected light imaged by said imaging means at a distant focal plane, said imaged light comprising rows or columns of pixels arranged so that adjacent pixels adds constructively to providing continuous, substantially smooth, straight regions of light and dark lines, said lines having a minimum width which is a single row or a single column of said pixels;

    b) means for individually moving each of said micromirrors in said two-dimensional array of micromirrors;

    c) means for controlling the movement and orientation of each of said micromirrors such that said reflected light is directed either into or away from said imaging means entrance pupil; and

    d) sequencing means in communication with said controlling means, said sequencing means for causing each of said micromirrors to move in proper sequence so as to scan a predetermined coordinate pattern across said two dimensional array of micromirrors, in a scan direction, thereby causing said pattern to be reproduced at said focal plane, said sequencing means including temporally interleaving rows of said micromirrors where said rows are parallel to said scan direction.

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