Projection Optical Device And Exposure Apparatus

Abstract

A projection optical device includes a projection optical system which projects an image of a pattern, a support device having a flexible structure to support the projection optical system, and a positioning device having an actuator to position the projection optical system. The projection optical device can include a frame to which one end of the flexible structure is attached. The projection optical system may hang from the frame via the support device, or it may be supported from below by the support device. A projection optical device also can include a liquid supply which supplies a temperature-controlled liquid to a side surface of a projection optical system utilizing gravity to cause the temperature-controlled liquid to flow along the side surface of the projection optical system.

1 . A projection optical device comprising: 
 a projection optical system which projects an image of a pattern;    a support device having a flexible structure to support the projection optical system; and    a positioning device having an actuator to position the projection optical system.    
   
   
       2 . The projection optical device of  claim 1 , wherein the flexible structure has a lower characteristic frequency in a direction perpendicular to an optical axis of the projection optical system than in a direction parallel to the optical axis of the projection optical system.  
   
   
       3 . The projection optical device of  claim 1 , wherein the flexible structure includes a wire.  
   
   
       4 . The projection optical device of  claim 3 , wherein the flexible structure includes a flexure coupled to the wire.  
   
   
       5 . The projection optical device of  claim 4 , wherein the flexure is a spring.  
   
   
       6 . The projection optical device of  claim 1 , wherein a length of the flexible structure is at least 1 meter.  
   
   
       7 . The projection optical device of  claim 1 , wherein the flexible structure includes a rod member and a flexure provided on at least one end of the rod member.  
   
   
       8 . The projection optical device of  claim 7 , wherein the rod member has a flexure provided on both ends of the rod member.  
   
   
       9 . The projection optical device of  claim 1 , wherein the support device supports the projection optical system from an upper side of the projection optical system.  
   
   
       10 . The projection optical device of  claim 1 , wherein the support device supports the projection optical system from below the projection optical system.  
   
   
       11 . The projection optical device of  claim 1 , further comprising a vibration isolation portion which reduces a vibration in an optical axis direction of the projection optical system, the vibration isolation portion is provided at one end of the flexible structure.  
   
   
       12 . The projection optical device of  claim 1 , wherein the support device comprises a frame to which one end of the flexible structure is attached, such that the projection optical system hangs from the frame via the flexible structure.  
   
   
       13 . The projection optical device of  claim 12 , wherein the actuator positions the projection optical system with respect to the frame in a non-contact manner.  
   
   
       14 . The projection optical device of  claim 13 , wherein the positioning device comprises: 
 a displacement sensor which measures six degrees-of-freedom of displacement information of the projection optical system with respect to the frame.    
   
   
       15 . The projection optical device of  claim 1 , wherein the support device supports the projection optical system via a flange portion fixed to a side surface of the projection optical system; and further comprising a measuring unit which is kinematically supported with respect to the flange portion and which is provided with a sensor for measuring a positional relationship between the projection optical system and a predetermined member.  
   
   
       16 . The projection optical device of  claim 1 , wherein a member in which the pattern is formed is integrally fixed to the projection optical system.  
   
   
       17 . The projection optical device of  claim 16 , further comprising a micro-moving mechanism which micro-moves the member in which the pattern is formed with respect to the projection optical system.  
   
   
       18 . The projection optical device of  claim 1 , wherein the support device comprises a frame to which one end of the flexible structure is attached, such that the projection optical system hangs from the frame via the flexible structure; and further comprising: 
 a base which is supported by the frame via a vibration isolation member; and    a stage which drives a member in which the pattern is formed, on the base.    
   
   
       19 . The projection optical device of  claim 18 , wherein the vibration isolation member includes one of a pivot and a flexure.  
   
   
       20 . The projection optical device of  claim 18 , further comprising: 
 a countermass which moves on the base so as to cancel a reaction force that is generated by movement of the stage; and    a flexure which supports the countermass on the base.    
   
   
       21 . The projection optical device of  claim 1 , wherein the projection optical system is arranged in a downflow environment.  
   
   
       22 . The projection optical device of  claim 15 , wherein the measuring unit includes a laser interferometer, and further comprising a local gas flow system which performs a local downflow of a gas with respect to an optical path of a laser beam used by the laser interferometer.  
   
   
       23 . The projection optical device of  claim 1 , further comprising: 
 a tube which is arranged along a side surface of the projection optical system; and    a liquid supply which supplies a cooling liquid to the tube.    
   
   
       24 . An exposure apparatus provided with the projection optical device of  claim 1 , wherein an image of the pattern is transferred and exposed onto a substrate by the projection optical system.  
   
   
       25 . A projection optical device comprising: 
 a projection optical system which projects an image of a pattern; and    a liquid supply which supplies a temperature-controlled liquid to a side surface of the projection optical system utilizing gravity to cause the temperature-controlled liquid to flow along the side surface of the projection optical system.    
   
   
       26 . The projection optical device of  claim 25 , wherein the liquid supply comprises: 
 a tube which is wrapped around the side surface of the projection optical system; and    a liquid circulation system which circulates the temperature-controlled liquid through the tube by a siphon principle.    
   
   
       27 . An exposure apparatus provided with the projection optical device of  claim 25 , wherein an image of the pattern is transferred and exposed onto a substrate by the projection optical system.  
   
   
       28 . The projection optical device of  claim 25 , wherein the liquid supply comprises: 
 a liquid reservoir located adjacent to a vertically upper portion of the projection optical system;    the tube which is wrapped around the side surface of the projection optical system, the tube in communication with the liquid reservoir; and    a liquid return path through which the fluid that has passed through the tube is returned to the liquid reservoir.    
   
   
       29 . The projection optical device of  claim 28 , wherein the liquid return path includes a temperature control system that controls the temperature of the liquid, the temperature control system includes a pump that pumps the liquid to the liquid reservoir.  
   
   
       30 . A method of controlling a temperature of a projection optical system which projects an image of a pattern in a projection optical device, the method comprising: 
 supplying a temperature-controlled liquid to a side surface of the projection optical system utilizing gravity to cause the temperature-controlled liquid to flow along the side surface of the projection optical system.    
   
   
       31 . The method of  claim 30 , wherein: 
 the temperature-controlled liquid is supplied through a tube which is wrapped around the side surface of the projection optical system in order to control the temperature of the projection optical system; and further comprising:    circulating the cooling liquid through the tube by a siphon principle.    
   
   
       32 . The method of  claim 30 , further comprising: 
 providing a liquid reservoir located adjacent to a vertically upper portion of the projection optical system;    supplying the temperature-controlled liquid to the tube which is wrapped around the side surface of the projection optical system from the liquid reservoir; and    returning the fluid that has passed through the tube to the liquid reservoir by a liquid return path.    
   
   
       33 . The method of  claim 32 , further comprising: 
 controlling the temperature of the liquid in the liquid return path by using a temperature control system; and    pumping the liquid through the liquid return path and into the liquid reservoir by using a pump.    
   
   
       34 . A method of supporting a projection optical system which projects an image of a pattern in a projection optical device, the method comprising: 
 supporting the projection optical system by a flexible structure of a support device; and    positioning the projection optical system by an actuator of a positioning device.    
   
   
       35 . The method of  claim 34 , wherein the flexible structure has a lower characteristic frequency in a direction perpendicular to an optical axis of the projection optical system than in a direction parallel to the optical axis of the projection optical system.  
   
   
       36 . The method of  claim 34 , wherein the flexible structure includes a wire.  
   
   
       37 . The method of  claim 36 , wherein the flexible structure includes a flexure coupled to the wire.  
   
   
       38 . The method of  claim 37 , wherein the flexure is a spring.  
   
   
       39 . The method of  claim 34 , wherein a length of the flexible structure is at least 1 meter.  
   
   
       40 . The method of  claim 34 , wherein the flexible structure includes a rod member and a flexure provided on at least one end of the rod member.  
   
   
       41 . The method of  claim 40 , wherein the rod member has a flexure provided on both ends of the rod member.  
   
   
       42 . The method of  claim 34 , wherein the support device supports the projection optical system from an upper side of the projection optical system.  
   
   
       43 . The method of  claim 34 , wherein the support device supports the projection optical system from below the projection optical system.  
   
   
       44 . The method of  claim 34 , further comprising: 
 providing a vibration isolation portion at one end of the flexible structure, the vibration isolation portion reduces a vibration in an optical axis direction of the projection optical system.    
   
   
       45 . The method of  claim 34 , wherein the support device comprises a frame to which one end of the flexible structure is attached, such that the projection optical system hangs from the frame via the flexible structure.  
   
   
       46 . The method of  claim 45 , wherein the actuator positions the projection optical system with respect to the frame in a non-contact manner.  
   
   
       47 . The method of  claim 46 , wherein the actuator measures six degrees-of-freedom of displacement information of the projection optical system with respect to the frame.  
   
   
       48 . The method of  claim 34 , wherein the support device supports the projection optical system via a flange portion fixed to a side surface of the projection optical system, and further comprising: 
 providing a measuring unit which is kinematically supported with respect to the flange portion and which includes a sensor for measuring a positional relationship between the projection optical system and a predetermined member.    
   
   
       49 . The method of  claim 34 , further comprising: 
 providing a micro-moving mechanism which micro-moves a member in which the pattern is formed with respect to the projection optical system.    
   
   
       50 . The method of  claim 34 , wherein the support device comprises a frame to which one end of the flexible structure is attached, such that the projection optical system hangs from the frame via the flexible structure; and further comprising: 
 providing a base which is supported by the frame via a vibration isolation member; and    providing a stage which drives a member in which the pattern is formed, on the base.    
   
   
       51 . The method of  claim 50 , wherein the vibration isolation member includes one of a pivot and a flexure.  
   
   
       52 . The method of  claim 50 , further comprising: 
 providing a countermass which moves on the base so as to cancel a reaction force that is generated by movement of the stage; and    providing a flexure which supports the countermass on the base.    
   
   
       53 . The method of  claim 34 , further comprising: 
 arranging the projection optical system in a downflow environment.    
   
   
       54 . The method of  claim 48 , wherein the measuring unit includes a laser interferometer, and further comprising: 
 providing a local gas flow system which performs a local downflow of a gas with respect to an optical path of a laser beam used by the laser interferometer.    
   
   
       55 . The method of  claim 34 , further comprising: 
 providing a tube which is arranged along a side surface of the projection optical system; and    providing a liquid supply which supplies a cooling liquid to the tube.