Exposure apparatus for production of integrated circuit

Abstract

An exposure apparatus for production of ICs of the type that includes a stage on which is placed a semiconductor wafer to be exposed by illumination light projecting means, and means for two-dimensionally moving the stage within a plane intersecting the illumination light at substantially right angles. The improvement comprises illumination detection means provided with a photo reception surface, and means for mounting the illumination detection means on the stage in such a manner that the photo reception surface and the surface of the semiconductor wafer on the stage to be exposed are at substantially equal height relative to the stage.

We claim: 
     
       1. In an exposure apparatus for production of integrated circuits including a stage on which a semiconductor wafer is placed for exposure by illumination light projecting means and means for two-dimensionally displacing said stage in a plane intersecting the illumination light at substantially right angles, an improvement comprising: illumination detecting means having a photo reception surface; and   means for .Iadd.fixedly .Iaddend.mounting said illumination detecting means on said stage in such manner that said photo reception surface lies substantially at the same level as the exposed surface of said semiconductor wafer on said stage relative to said stage.   
     
     
       2. The improvement as set forth in claim 1, wherein said illumination light projecting means is so mounted as to illuminate a selected area on said stage and wherein said illumination detecting means is mounted out of said selected area on said stage. 
     
     
       3. The improvement as set forth in claim 2 which further comprises means for guiding said illumination detecting means into said selected area. 
     
     
       4. The improvement as set forth in claim 3, wherein said displacing means includes means for detecting the position of said illumination detecting means and means for driving said stage in response to said position detecting means. 
     
     
       5. The improvement as set forth in claim 1, wherein said mounting means includes an intercepting member having an opening therethrough that is very small in area parallel to said plane relative to the area of the photo reception surface parallel to said plane to limit the light receivable area on the photo reception surface of said illumination detecting means. 
     
     
       6. The improvement as set forth in claim 1, wherein said illumination detecting means comprises a one-dimensional photo sensor. 
     
     
       7. The improvement as set forth in claim 1, wherein said illumination detecting means comprises a two-dimensional photo sensor. 
     
     
       8. In an exposure apparatus for production of integrated circuits in which a pattern is illuminated to print an image of the pattern through an optical system onto a surface to be exposed of a semiconductor wafer having predetermined thickness, an improvement comprising: (a) a stage having a surface for supporting said semiconductor wafer thereon at a predetermined location with said semiconductor wafer surface to be exposed oriented substantially perpendicular to the optical axis of said optical system, the stage being supported to move on a two-dimensional plane substantially orthogonal to said optical axis;   (b) limiting means providing a limited area through which light passes, said limiting means being integral with said stage and positioned at a location on said stage spaced laterally away from said predetermined location;   (c) means detecting the light which passes through said limiting means to convert it into an electric signal, said detecting means .Iadd.being fixedly mounted on said stage and .Iaddend.having a photo reception surface that is at substantially the same level relative to said stage surface as the surface of the semiconductor wafer to be exposed; and   (d) means for detecting the position of said stage on said two-dimensional plane.   
     
     
       9. In an exposure apparatus for production of integrated circuits in which a pattern is illuminated to print an image of the pattern through an optical system onto a surface to be exposed of a semiconductor wafer, an improvement comprising: (a) a stage on which said semiconductor wafer is supported with said semiconductor wafer surface to be exposed substantially perpendicular to the optical axis of said optical system, the stage being supported to move on a two-dimensional plane substantially orthogonal to said optical axis;   (b) illumination detecting means having a photo reception surface and being provided with an intercepting member having an opening formed therethrough that is very small in area parallel to said plane relative to the area of the photo reception surface parallel to said plane to limit the light receivable area on the photo reception surface, the illumination detecting means including means to support said photo reception surface .Iadd.fixedly .Iaddend.on said stage at a level substantially coincident with the level of said semiconductor wafer surface to be exposed; and   (c) means detecting the position of said stage on said two-dimensional plane.   
     
     
       10. The improvement as set forth in claim 9, wherein said illumination detecting means includes a photoelectric element for detecting the light which passes through said opening to convert it into an electric signal. .Iadd. 
     
     
       11.  The improvement as set forth in claim 1, wherein said illumination detecting means is embedded in said stage. .Iaddend. .Iadd.12. The improvement as set forth in claim 8, wherein said detecting means is embedded in said stage. .Iaddend. .Iadd.13. The improvement as set forth in claim 9, wherein said illumination detecting means is embedded in said stage. .Iaddend. .Iadd.14. An exposure apparatus for production of integrated circuits comprising: (a) illuminating means for illuminating a reticle;   (b) a stage provided with a supporting surface for supporting a wafer on said supporting surface;   (c) moving means for moving said stage on a two-dimensional plane which is parallel to a surface to be exposed of said wafer;   (d) position detecting means for detecting the position of said stage on said two-dimensional plane;   (e) illumination light detecting means having a detection surface; and   (f) mounting means for mounting said illumination light detecting means fixedly on said stage so that said detection surface is substantially at the same level as said surface of the wafer and said illumination light detecting means is out of an area of said stage where said wafer is disposed. .Iaddend. .Iadd.15. An apparatus according to claim 14, wherein said light detecting means is embedded in said stage. .Iaddend. .Iadd.16. An exposure apparatus for production of integrated circuits comprising:   (a) illuminating means for illuminating a reticle, said illuminating means having an optical system for forming a minified image of the illuminated reticle on a predetermined plane so that the size of said image of said reticle is smaller than the size of said reticle;   (b) a stage provided with a supporting surface for supporting a wafer on said supporting surface so that a surface to be exposed of said wafer is substantially at the same level as said predetermined plane;   (c) moving means for moving said stage on a two-dimensional plane which is parallel to said predetermined plane;   (d) position detecting means for detecting the position of said stage on said two-dimensional plane;   (e) light detecting means having a detection surface, said detecting means detecting an intensity of light incident on said detection surface to produce an electric signal conforming to the detected intensity; and   (f) mounting means for mounting said light detecting means fixedly on said stage so that said detection surface is substantially at the same level as said predetermined plane and said detecting means is out of an area of said stage where said wafer is disposed. .Iaddend. .Iadd.17. An apparatus according to claim 16, wherein said light detecting means has a photoelectric conversion element and a light intercepting member provided with an opening, and said photoelectric conversion element is attached to said light intercepting member so that said photoelectric conversion element detects light from said illuminating means through said opening. .Iaddend. .Iadd.18. An apparatus according to claim 17, wherein said stage has the shape of a rectangle and said light detecting means is disposed adjacent to one of the corners of said rectangle. .Iaddend. .Iadd.19. An apparatus according to claim 17, wherein said position detecting means has two interference range finders which measure a position of said stage in two directions which are perpendicular to each other. .Iaddend. .Iadd.20. An apparatus according to claim 16, wherein said light detecting means is embedded in said stage. .Iaddend. .Iadd.21. An exposure apparatus for production of integrated circuits comprising:   (a) illuminating means for illuminating a reticle, said illuminating means having an optical system for forming a minified image of the illuminated reticle on a predetermined plane so that the size of said image of said reticle is smaller than the size of said reticle;   (b) a stage for supporting a wafer thereon so that a surface to be exposed of said wafer is substantially at the same level as said predetermined plane;   (c) moving means for moving said stage on a two-dimensional plane which is parallel to said predetermined plane; and   (d) measuring means for detecting positions of rise and fall of an illumination distribution of the image of said illuminated reticle on said predetermined plane to measure the size of an exposure area corresponding to the image of the illuminated reticle, said measuring means including light detecting means, mounting means for mounting said light detecting means fixedly on said stage, and position detecting means for detecting each of the positions of said stage on said two-dimensional plane, said light detecting means having a detection surface and detecting an intensity of light incident on said detection surface to produce an electric signal conforming to the detected intensity, said mounting means mounting said light detecting means so that said detection surface is substantially at the same level as said predetermined plane and said detecting means is out of an area of said stage where said wafer is   
     
     
        disposed. .Iaddend. .Iadd.22.  An apparatus according to claim 21, wherein said light detecting means has a photoelectric conversion element and a light intercepting member provided with an opening, and said photoelectric conversion element is attached to said light intercepting member so that said photoelectric conversion element detects light from said illuminating means through said opening. .Iaddend. .Iadd.23. An apparatus according to claim 22, wherein said stage has the shape of a rectangle and said light detecting means is mounted adjacent to one of the corners of said rectangle. .Iaddend. .Iadd.24. An apparatus according to claim 21, wherein said light detecting means is embedded in said stage. .Iaddend. .Iadd.25. An exposure apparatus for production of integrated circuits comprising: (a) illuminating means for illuminating a reticle, said illuminating means having an optical system for forming a minified image of the illuminated reticle on a predetermined plane so that the size of said image of said reticle is smaller than the size of said reticle;   (b) a stage provided with a supporting surface for supporting a wafer on said supporting surface so that a surface to be exposed of said wafer is substantially at the same level as said predetermined plane;   (c) moving means for moving said stage on a two-dimensional plane which is parallel to said predetermined plane;   (d) position detecting means for detecting the position of said stage on said two-dimensional plane;   (e) light detecting means having a detection surface, said detecting means detecting an intensity of light incident on said detection surface to produce an electric signal conforming to the detected intensity; and   (f) mounting means for mounting said light detecting means fixedly on said stage so that said detection surface is substantially at the same level as   
     
     
        said predetermined plane. .Iaddend. .Iadd.26.  An apparatus according to claim 25, wherein said light detecting means is embedded in said stage. .Iaddend. .Iadd.27. An exposure apparatus for production of integrated circuits comprising: (a) illuminating means for illuminating a reticle, said illuminating means having an optical system for forming a minified image of the illuminated reticle on a predetermined plane so that the size of said image of said reticle is smaller than the size of said reticle;   (b) a stage for supporting a wafer thereon so that a surface to be exposed of said wafer is substantially at the same level as said predetermined plane;   (c) moving means for moving said stage on a two-dimensional plane which is parallel to said prerdetermined plane; and   (d) measuring means for detecting positions of rise and fall of an illumination distribution image of the illuminated reticle on said predetermined plane to measure the size of an exposure area corresponding to the image of said illuminated reticle, said measuring means including light detecting means, mounting means for mounting said light detecting means fixedly on said stage, and position detecting means for detecting each of the positions of said stage on said two-dimensional plane, said light detecting means having a detection surface and detecting an intensity of light incident on said detection surface to produce an electric signal conforming to the detected intensity, said mounting means mounting said light detecting means so that said detection surface is substantially at the same level as said predetermined plane. .Iaddend.   
     
     
        .Iadd.28.  An apparatus according to claim 27, wherein said light detecting means is embedded in said stage. .Iaddend.