Method of exposing a semiconductor wafer and exposure apparatus

Abstract

An exposure apparatus includes an autofocus scan processor configured to generate a detection signal indicating a defocused portion of a resist film over a semiconductor substrate, an exposure scan processor configured to perform an exposure process for the resist film, and a controller configured to feed back the detection signal from the autofocus scan processor to the exposure scan processor.

What is claimed is: 
     
         1 . An exposure apparatus comprising:
 an autofocus scan processor configured to generate a detection signal indicating a defocused portion of a resist film over a semiconductor substrate;   an exposure scan processor configured to perform an exposure process for the resist film; and   a controller configured to feed back the detection signal from the autofocus scan processor to the exposure scan processor.   
     
     
         2 . The exposure apparatus according to  claim 1 , wherein the controller is configured to feed back the detection signal so that the defocused portion of the resist film is selectively blinded. 
     
     
         3 . The exposure apparatus according to  claim 1 , wherein the controller is configured to feed back the detection signal so that a portion of the resist film other than the defocused portion is selectively blinded. 
     
     
         4 . The exposure apparatus according to  claim 1 , wherein the autofocus scan processor is further configured to illuminate exposure beams of light on the resist film at a scanning pitch of at most 1 mm. 
     
     
         5 . The exposure apparatus according to  claim 1 ,
 wherein the autofocus scan processor is further configured to measure height-direction positions on a surface of the resist film, and   wherein the autofocus scan processor is further configured to perform a three-dimensional analysis of information of the height-direction positions to detect the defocused portion.   
     
     
         6 . The exposure apparatus according to  claim 5 ,
 wherein the exposure scan processor is further configured to move at least one of blinding plates to extend across an exposure slit, and   wherein the exposure scan processor is further configured to blind the defocused portion with reference to the detection signal.   
     
     
         7 . The exposure apparatus according to  claim 6 ,
 wherein the exposure scan processor is further configured to store an identification information identifying the semiconductor wafer and the information of the height-direction positions, and   wherein at least one of the blinding plates is configured to move with reference to the identification information and the information of the height-direction positions.   
     
     
         8 . The exposure apparatus according to  claim 1 ,
 wherein the autofocus scan processor is further configured to measure height-direction positions on a surface of the resist film, and   wherein the autofocus scan processor is further configured to detect the defocused portion with reference to information related to the height-direction positions measured.   
     
     
         9 . The exposure apparatus according to  claim 8 ,
 wherein the autofocus scan processor is further configured to calculate differences between measured heights and an adjustable height to identify the differences as calculated defocus values, the measured heights being respectively defined by the height-direction positions measured,   wherein the autofocus scan processor is further configured to compare the calculated defocus values to a reference defocus value at positions on the surface of the resist film, and   wherein the autofocus scan processor is further configured to identify the defocused portion at a position where the calculated defocus value exceeds the reference defocus value.   
     
     
         10 . The exposure apparatus according to  claim 9 ,
 wherein the autofocus scan processor is further configured to detect heights and inclinations of the surface of the resist film from the height-direction positions measured, and   wherein the autofocus scan processor is further configured to detect the defocused portion with reference to the heights and the inclinations detected.   
     
     
         11 . The exposure apparatus according to  claim 10 ,
 wherein the autofocus scan processor is further configured to calculate high and inclination baselines from the height-direction positions measured,   wherein the autofocus scan processor is further configured to determine whether a focused plane is offset from a base-plane which is made by the high and inclination baselines, and   wherein the autofocus scan processor is further configured to determine whether the focused plane has a three-dimensionally upwardly bulging shape.   
     
     
         12 . An exposure apparatus comprising:
 an autofocus scan processor configured to detect a defocus portion of a resist film over a semiconductor substrate by measuring height-direction positions of the resist film, and to generate a detection signal that indicates the defocus portion;   an exposure scan processor configured to perform an exposure process for the resist film, the exposure scan processor comprising a selective blinding mechanism; and   a controller configured to control the selective blinding mechanism by feeding back the detection signal from the autofocus scan processor to the exposure scan processor.   
     
     
         13 . The exposure apparatus according to  claim 12 , wherein the controller is configured to selectively blind the defocused portion of the resist film with reference to the detection signal. 
     
     
         14 . The exposure apparatus according to  claim 12 , wherein the selective blinding mechanism comprises a blinding plate to extend across an exposure slit and to blind the defocused portion. 
     
     
         15 . The exposure apparatus according to  claim 14 , wherein the blinding plate comprises at least one of narrow blinding plates arranged in a line at one side of the exposure slit, a half-crescent shaped blinding plate, a triangular blinding plate, and a trapezoidal blinding plate. 
     
     
         16 . An exposure apparatus comprising:
 an autofocus scan processor configured to perform an autofocus scan processing to measure height-direction positions on a surface of a resist film over a semiconductor wafer, the autofocus scan processor being configured to perform a three-dimensional analysis of information of the height-direction positions to generate a detection signal indicating a defocused portion of the resist film;   an exposure scan processor including a selective blinding mechanism configured to selectively blind the resist film, the exposure scan processor configured to perform an exposure process for the resist film; and   a controller configured to receive the detection signal indicating the defocused portion from the autofocus scan processor, the controller configured to control the selective blinding mechanism to selectively blind the resist film with reference to the detection signal.   
     
     
         17 . The exposure apparatus according to  claim 16 , wherein the selective blinding mechanism comprises an exposure slit and a plurality of blinding plates which is movable to extend across the exposure slit. 
     
     
         18 . The exposure apparatus according to  claim 17 , wherein the controller controls to move at least one of the plurality of blinding plates to extend across the exposure slit to selectively blind the resist film with reference to the detection signal. 
     
     
         19 . The exposure apparatus according to  claim 17 , further comprising a defocusing information storage unit storing an identification information identifying the semiconductor wafer. 
     
     
         20 . The exposure apparatus according to  claim 19 ,
 wherein the controller acquires the identification information from the defocusing information storage unit, and   wherein the controller controls to move at least one of the plurality of blinding plates with reference to the identification information.