Lithographic apparatus and device manufacturing method that compensates for reticle induced CDU

Abstract

A lithographic apparatus operable in a substrate exposing configuration to expose a substrate with a pattern of radiation and a radiation beam inspection configuration in which the pattern of radiation that would be exposed on the substrate if the lithographic apparatus was in the substrate exposing configuration is inspected by a radiation beam inspection device. In the radiation beam inspecting configuration, the operation of the lithographic apparatus is modified in order to minimize the difference between the pattern of radiation exposed on the substrate and the required pattern of radiation to be exposed on the substrate.

1 . A lithographic apparatus, comprising: 
 an illumination system that conditions a radiation beam;    a patterning device that modulates the radiation beam;    a projection system that projects the modulated radiation beam onto a target portion of a substrate; and    a radiation beam inspection device that inspects at least a part of the modulated radiation beam;    wherein in a substrate exposing configuration, the lithographic apparatus exposes a pattern of radiation on the substrate using the modulated radiation beam, and    wherein in a radiation beam inspecting configuration, the radiation beam inspection device inspects the pattern of radiation that would be exposed on the substrate if the lithographic apparatus was in the substrate exposing configuration.    
   
   
       2 . The lithographic apparatus of  claim 1 , wherein the radiation beam inspection device is mounted to a substrate table that supports the substrate.  
   
   
       3 . The lithographic apparatus of  claim 2 , wherein: 
 the substrate has an upper surface on which the radiation is projected that substantially lies within a first plane when a substrate is supported by the substrate table and the lithographic apparatus is in the substrate exposing configuration;    the radiation beam inspection device is mounted to the substrate table adjacent a portion of the substrate table that supports the substrate; and    the lithographic apparatus comprises an actuator that moves at least a part of the substrate table relative to the projection system such that, in the substrate exposing configuration, the projection system projects the modulated beam of radiation onto the substrate and, in the radiation beam inspecting configuration, the projection system projects the modulated beam of radiation onto the radiation beam inspection device which substantially lies in said first plane.    
   
   
       4 . The lithographic apparatus of  claim 2 , wherein the radiation beam inspection device is mounted to the substrate table such that, when a substrate is supported by the substrate table, the substrate is supported at a location between the projection system and the radiation beam inspection device and, in the radiation beam inspecting configuration, no substrate is supported at said location.  
   
   
       5 . The lithographic apparatus of  claim 1 , wherein the radiation beam inspection device is supported on a substrate table in place of the substrate.  
   
   
       6 . The lithographic apparatus of  claim 1 , wherein the lithographic apparatus further comprises: 
 an optical element that controls the modulated radiation beam projected by the projection system wherein, when the optical element is set to a first setting, the modulated beam of radiation is projected onto a substrate supported on the substrate table, and when the optical element is set to a second setting, the modulated beam of radiation is projected onto the radiation beam inspection device.    
   
   
       7 . The lithographic apparatus of  claim 1 , further comprising: 
 a required pattern data store that stores data corresponding to at least a part of a required pattern to be exposed on a substrate; and    a correction controller that determines the difference between the pattern detected by the radiation beam inspection device with the required pattern and determines at least one modification of the operation of the lithographic apparatus necessary in order to minimize said difference.    
   
   
       8 . The lithographic apparatus of  claim 7 , wherein: 
 operation of the lithographic apparatus modified according to the modifications determined by the correction controller while the lithographic apparatus is in the radiation beam inspecting configuration; and    the correction controller determines any remaining differences between the pattern detected by the radiation beam inspection device and the required pattern and determine any further modification of the operation of the lithographic apparatus necessary in order to minimize said difference.    
   
   
       9 . The lithographic apparatus of  claim 7 , wherein: 
 the patterning device is an array of individually controllable elements; and    said at least one modification of the operation of the lithographic apparatus comprises at least one change to the pattern to be set by the array of individually controllable elements.    
   
   
       10 . The lithographic apparatus of  claim 9 , wherein said at least one change to the pattern to be set by the array of the individually controllable elements comprises at least one of an addition of a pattern feature, a removal of a pattern feature, and a re-sizing of a pattern feature.  
   
   
       11 . The lithographic apparatus of  claim 9 , wherein: 
 said array of individually controllable elements is constructed such that the intensity of portions of the modulated radiation beam is set to at least three different levels; and    said at least one change to the pattern to be set by the array of individually controllable elements comprises adjusting an intensity of the modulated radiation beam in at least one portion of the pattern of radiation.    
   
   
       12 . The lithographic apparatus of  claim 9 , further comprising a corrected pattern data store that stores pattern data, corresponding to said required pattern to be exposed on the substrate, modified according to the at least one change to the pattern to be set by the array of individually controllable elements determined by the correction controller and the array of individually controllable elements is set according to the pattern data in said corrected pattern data store.  
   
   
       13 . The lithographic apparatus of  claim 9 , further comprising: 
 a pattern corrections data store that stores data corresponding to the at least one change to the pattern to be set by the array of individually controllable elements determined by the correction controller; and    the array of individually controllable elements is set according to the required pattern data stored in the required pattern data store corrected by the data stored in the pattern corrections data store.    
   
   
       14 . The lithographic apparatus of  claim 7 , wherein said at least one modification of the operation of the lithographic apparatus comprises at least one of an alteration of an intensity of the radiation beam provided by the illumination system, an alteration of the conditioning of the radiation beam by the illumination system, and an alteration of one or more settings of the projection system.  
   
   
       15 . The lithographic apparatus of  claim 14 , further comprising: 
 a system settings data store that stores data corresponding to said alteration of at least one of the intensity of the radiation beam provided by the illumination system, the conditioning of the radiation beam by the illumination system and one or more settings of the projection system; and    the lithographic apparatus, when in the substrate exposing configuration, is controlled by a system controller that uses the data stored in the system settings data store.    
   
   
       16 . The lithographic apparatus of  claim 7 , wherein said required pattern to be exposed on the substrate is a pattern corresponding to pattern features required to be formed on the substrate, modified according to a characterization of differences resulting from variations in conditions of processing the substrate, between the pattern of radiation exposed on the substrate, and the pattern features formed on the substrate.  
   
   
       17 . The lithographic apparatus of  claim 7 , wherein said required pattern data store stores data corresponding to at least a part of a pattern of features required to be formed on the substrate and a characterization of differences, resulting from variations in conditions of processing the substrate, between the pattern of radiation exposed on the substrate and the pattern features formed on the substrate; and 
 the correction controller determines the pattern required to be exposed on the substrate from the data stored in said required pattern data store.    
   
   
       18 . A method of optimizing operation of a lithographic apparatus for formation of a device on a substrate using a lithographic apparatus, the method comprising: 
 modulating a radiation beam using a patterning device;    projecting the modulated beam of radiation onto a radiation beam inspection device that inspects at least a part of the modulated radiation beam to determine a corresponding pattern that would be exposed on a substrate if the modulated beam of radiation were projected on the substrate; and    determining at least one modification of the operation of the lithographic apparatus to minimize the difference between a required pattern to be exposed on the substrate and the pattern determined by the radiation beam inspection device.    
   
   
       19 . The method of  claim 18 , further comprising; 
 modifying the operation of the lithographic apparatus to minimize the difference between the required pattern to be exposed on the substrate and the pattern determined by the radiation beam inspection device; and    projecting the modulated beam of radiation onto a substrate.    
   
   
       20 . A flat panel display manufactured according to the method of  claim 19 .  
   
   
       21 . An integrated circuit device manufactured according to the method of  claim 19.