Light illumination device
Illumination optical arrangement
Optical apparatus using polarized light
Observation apparatus with selective light diffusion
Illuminating optical system
Scan and repeat high resolution projection lithography system
Projection exposure apparatus
Illuminating optical device
ApplicationNo. 470482 filed on 06/06/1995
US Classes:355/53, Step and repeat355/67Illumination systems or details
ExaminersPrimary: Braun, Fred L.
Attorney, Agent or Firm
Foreign Patent References
International ClassG03B 027/42
Foreign Application Priority Data1991-02-22 JP
AbstractAn exposure apparatus for and a method of forming an image of a fine pattern having linear features extending in orthogonal first and second directions. The apparatus includes an illumination optical system for illuminating the pattern. The illumination optical system includes a device for forming a secondary light source having decreased intensity portions at a center thereof and on first and second intersecting axes defined along the first and second directions, respectively. A projection optical system projects, on an image plane, an image of the pattern illuminated with light from the light source. The light source includes four sections having substantially the same intensity and being distributed in the four quadrants defined by the axes. An image of the light source is projected onto a pupil of the projection optical system. On the assumption of a coordinate system defined X and Y-axes extending along the first and second directions and intersecting at a center of the pupil, and that a radius of the pupil is one, coordinates of centers of the four sections are (p, p), (-p, p), (-p, -p) and (p, -p), wherein 0.25<p<0.6.