Scanning Exposure Method

Abstract

Since a mask stage 16 and a substrate stage 14 are supported in a floating manner over a base member 12, the both stages are driven in mutually opposite directions in a non-contact manner along the scanning direction by the aid of a linear motor 13. During this process, the movement of the both stages 16, 14 does not exert any force on the base member 12 and other components, and thus the momentum is conserved. The mass ratio between the stage 16 and the stage 14 is set to be identical with a reduction magnification of an unillustrated projection optical system. Therefore, according to the law of conservation of momentum, the velocity ratio between the stage 16 and the stage 14 is a reciprocal number of the reduction magnification of the projection optical system. Thus, the both stages 16, 14 are subjected to accurate synchronous control. It is possible to suppress inclination and fluctuation of the entire apparatus, and it is possible to improve the synchronization performance of the mask stage and the substrate stage.

1 . An exposure apparatus for transferring a pattern formed on a mask onto a photosensitive substrate through a projection optical system while synchronously moving the mask and the photosensitive substrate, the exposure apparatus comprising: 
 a substrate stage supported in a floating manner over a base member;    a mask stage supported in a floating manner over the base member and having a mass corresponding to an amount obtained by multiplying a mass of the substrate stage by a reduction magnification of the projection optical system; and    a first linear motor provided between the substrate stage and the mask stage, for driving the substrate stage and the mask stage so that the mask and the substrate are moved in mutually opposite directions.    
     
     
         2 . The exposure apparatus according to    claim 1   , wherein the projection optical system is an optical system which projects an inverted image of the pattern formed on the mask onto the photosensitive substrate.  
     
     
         3 . The exposure apparatus according to    claim 1   , wherein the photosensitive substrate is held horizontally on the substrate stage, the mask is held vertically on the mask stage, and the projection optical system comprises a plurality of transmitting optical elements, a beam splitter, and a reflecting optical element, and wherein the optical system projects the pattern of the mask arranged on an object plane onto the photosensitive substrate arranged on an image formation plane at a predetermined reduction magnification.  
     
     
         4 . The exposure apparatus according to    claim 3   , further comprising a half TTL alignment detection system which is capable of detecting, via the beam splitter, both of an alignment mark formed on the mask and an alignment mask formed on the photosensitive substrate.  
     
     
         5 . The exposure apparatus according to    claim 1   , wherein a second linear motor for driving the mask stage is provided between the base member and the mask stage.  
     
     
         6 . The exposure apparatus according to    claim 5   , wherein a third linear motor for driving the substrate stage is provided between the base member and the substrate stage.  
     
     
         7 . The exposure apparatus according to    claim 6   , wherein at least one of the second linear motor and the third linear motor is provided with a regenerative braking circuit for finely adjusting a velocity ratio during synchronous movement of the both stages effected by the first linear motor.  
     
     
         8 . The exposure apparatus according to any one of claims  1 ,  5 ,  6 , and  7  wherein the substrate stage comprises a first stage which is movable in a first direction in which the photosensitive substrate is moved synchronously, with the mask stage and a second stage which is movable in the first direction integrally with the first stage while holding the photosensitive substrate and which is movable in a second direction perpendicular to the first direction by being guided by the first stage.  
     
     
         9 . The exposure apparatus according to    claim 1   , wherein the substrate stage is supported in the floating manner over the base member via an air bearing.  
     
     
         10 . The exposure apparatus according to    claim 1   , wherein the mask stage is supported in the floating manner over the base member via an air bearing.  
     
     
         11 . A scanning exposure apparatus having a projection optical system with an optical axis substantially perpendicular to a mask and a substrate respectively, for transferring a pattern formed on the mask onto the substrate through the projection optical system, the scanning exposure apparatus comprising: 
 a base;    a first stage for moving the mask over the base;    a second stage for moving the substrate over the base; and    a driving system connected to the first stage and the second stage, for synchronously moving the mask and the substrate at a velocity ratio corresponding to a magnification of the projection optical system, wherein: 
 the driving system drives the first stage and the second stage along predetermined directions oppositely to one another so that a reactive force generated by the synchronous movement is offset.  
   
     
     
         12 . The scanning exposure apparatus according to    claim 11   , wherein a mass ratio between the first stage and the second stage is substantially coincident with a projection magnification of the projection optical system.  
     
     
         13 . The scanning exposure apparatus according to    claim 11    or    12   , wherein the projection optical system comprises a refractive optical element and at least one reflecting optical element, and the projection optical system reduces and projects a partial inverted image of the pattern on the mask onto the substrate.  
     
     
         14 . The scanning exposure apparatus according to    claim 11    or    12   , wherein the projection optical system comprises at least two reflecting optical elements, and its image plane is arranged on a side of an object plane with respect to the projection optical system.  
     
     
         15 . The scanning exposure apparatus according to    claim 13   , wherein the projection optical system comprises, as the reflecting optical element, at least one of a mirror, a concave mirror, and a beam splitter.  
     
     
         16 . The scanning exposure apparatus according to    claim 14   , wherein the projection optical system comprises, as the reflecting optical element, at least one of a mirror, a concave mirror, and a beam splitter.  
     
     
         17 . The scanning exposure apparatus according to    claim 11   , wherein an object plane and an imag e plane of the projection optical system are arranged in an identical plane, and the first and second stages move the mask and the substrate along the plane respectively.  
     
     
         18 . The scanning exposure apparatus according to    claim 14   , wherein an object plane and an image plane of the projection optical system are arranged in an identical plane, and the first and second stages move the mask and the substrate along the plane respectively.  
     
     
         19 . The scanning exposure apparatus according to    claim 14   , further comprising an illumination system arranged on a side opposite to the projection optical system with respect to the base, for irradiating the mask with a light beam.  
     
     
         20 . The scanning exposure apparatus according to    claim 17   , further comprising an illumination system arranged on a side opposite to the projection optical system with respect to the base, for irradiating the mask with a light beam.  
     
     
         21 . The scanning exposure apparatus according to    claim 18   , further comprising an illumination system arranged on a side opposite to the projection optical system with respect to the base, for irradiating the mask with a light beam.  
     
     
         22 . A scanning exposure method for transferring a pattern formed on a mask onto a substrate through a projection optical system, the scanning exposure method comprising the steps of: 
 arranging the mask and the substrate in an identical plane perpendicular to an optical axis of the projection optical system;    projecting a partial inverted image of the pattern formed on the mask onto the substrate; and    synchronously moving the mask and the substrate oppositely to one another along predetermined directions on the plane so that a reactive force generated by the synchronous movement is substantially offset.    
     
     
         23 . The scanning exposure method according to    claim 22   , wherein the mask and the substrate are synchronously moved at a velocity ratio corresponding to a magnification of the projection optical system.  
     
     
         24 . The scanning exposure method according to    claim 22    or    23   , wherein in order to perform overlay transfer of the pattern on the mask onto a pattern on the substrate, a velocity ratio between the mask and the substrate is adjusted during the synchronous movement so that at least one of a magnification error and a distortion error between the pattern on the substrate and the image of the pattern on the mask is corrected.