Optical projection apparatus

• US 4,011,011 A
• Filed: 12/19/1974
• Issued: 03/08/1977
• Est. Priority Date: 03/09/1973
• Status: Expired due to Term

• Current Assignee: SVG Lithography Systems Incorporated (ASML Holding NV)
• Original Assignee: Perkinelmer Incorporated
• Inventors: Markle, David A., Offner, Abe, Newell, William H., Hemstreet, Harold S.
• Primary Examiner(s): O'Connor, Edna M.
• Application Number:
  US05/534,465
• Time in Patent Office: 810 Days
• Field of Search: 355/8, 355/18, 355/50, 355/51, 355/75, 355/54, 355/55, 355/45, 350/55, 354/79
• US Class Current: 355/18
• CPC Class Codes: G02B 17/0615 off-axis or unobscured systems in wich all of the mirrors share a common axis of rotational symmetry
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging

Abstract

A unity magnification catoptric image-forming system and an illumination system on the one hand, and an object- and image-surface supporting means on the other hand, are arranged for relative movement to retain the object and image surfaces in unity magnification conjugate planes of the catoptric system while effecting a scanning-type exposure of successive portions of the image surface to successively illuminated portions of the object. Fine motion mechanisms permit accurate preliminary adjustment of the object- and image-receiving surfaces relative to each other while under visual examination with the aid of the catoptric image-forming system.

Claims

1. Apparatus for photographically exposing an image-receiving surface to a light image of an object, said apparatus comprising:

a concave mirror,

a convex mirror of smaller radius of curvature with its center of curvature substantially at the center of curvature of the concave mirror,

means for supporting an object surface and an image-receiving surface with respect to each other and with respect to said mirrors so as to optically define a common image and optical plane,

said optically defined common image and optical plane being located a distance from the concave mirror substantially equal to the radius of curvature thereof,

said optically defined common image and optical plane containing the centers of curvature of said mirrors, and the perpendicular to the optically defined common image and optical plane through said centers of curvature constituting an axis of said mirrors,

means for illuminating an arcuate area at the site of the object surface which forms an arcuate light image area at the site of the imagereceiving surface,

said arcuate area at the site of the object surface and said arcuate light image area at the site of the image-receiving surface optically defining, on the optically defined common image and optical plane, arcuate images respectively having arcuate areas exterior of and substantially centered on said axis of the mirrors, and

means to advance said support means and the sites of the object and image-receiving surfaces to be supported thereon in their planes transversely of the means for illuminating the arcuate area on the object surface,

said advancing means comprising a carriage rotatable about an axis fixed with respect to said concave and convex mirrors.

2. Apparatus according to claim 1 including two plane reflecting means positioned between said mirrors and their centers of curvature, said reflecting means being inclined to each other and to said axis and being positioned to dispose said sites of the object and image receiving surfaces on said support means parallel to each other and to the axis of said mirrors.

3. Apparatus according to claim 2 wherein one of said plane reflecting means includes a single plane mirror and wherein the other of said plane reflecting means includes a pair of plane mirrors inclined to each other to form a line of intersection, said line of intersection being disposed in perpendicular relationship with respect to the plane of said single plane mirror.

4. Apparatus according to claim 3 wherein said plane mirrors are incorporated in a single rigid array.

5. Apparatus according to claim 3 wherein said pair of plane mirrors have mutually perpendicular reflecting plane faces, and wherein said line of intersection is inclined at substantially 45°

with respect to said axis of the mirrors.

6. Apparatus according to claim 2 wherein one of said plane reflecting means is partially transparent, and which includes means to examine the image of an image receiving surface on said support means produced by said concave and convex mirrors and transmitted through said partially transparent reflecting means.

7. Apparatus according to claim 6 wherein said examining means comprises two microscope objectives supported for arcuate motions about said axis of said concave and convex mirrors, prisms coupled respectively to each of said objectives to bring the axes of said objectives to be substantially collinear with said first mentioned axis, and means to present in a common eyepiece one half of the field of each of said objectives.

8. Apparatus according to claim 2 wherein the radius of curvature of the convex mirror is substantially equal to one-half the radius of curvature of the concave mirror increased by the square of the mean radius of the illuminated arcuate area at the site of the object surface divided by four times the radius of curvature of the concave mirror.