Abstract:
An exposure apparatus configured to measure a position of at least one of a mark formed on an original plate and a mark formed on a substrate and to expose the substrate to radiant energy based on the measured position includes a stage configured to hold one of the original plate and the substrate and to be moved, a scope configured to capture an image of the mark formed on one of the original plate and the substrate held by the stage, an input unit configured to be operated to instruct a position of the stage, a display, and a controller configured to combine images respectively captured by the scope at a plurality of positions of the stage instructed by the input unit into a combined image and to cause the display to display the combined image.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an exposure apparatus configured to measure the position of at least one of a mark formed on an original plate and a mark formed on a substrate and to expose the substrate to radiant energy based on the measured position. 
         [0003]    2. Description of the Related Art 
         [0004]    A semiconductor exposure apparatus is configured to print a circuit pattern on a wafer. For example, a stepper uses a mask (or a reticle), which is a transmitting plate with an original circuit pattern formed thereon. A conventional exposure method includes locating a wafer to a predetermined position and exposing the wafer to illumination light through a mask, thereby printing a circuit pattern drawn on the mask onto the wafer. 
         [0005]    An operator observes an alignment mark on a mask or a wafer via a microscope, captures an image of the alignment mark with a charge-coupled device (CCD) camera, and performs a positioning (alignment) operation for locating the mask or the wafer with reference to a result of image processing. In this alignment operation, if the operator cannot detect a target mark in a captured image, the operator moves a mask stage or a wafer stage. 
         [0006]    Namely, the operator manually moves the mask stage or the wafer stage while monitoring an image from the CCD camera, so that the alignment mark is present in a visual field of the CCD camera. A computer terminal associated with a semiconductor exposure apparatus enables an operator to perform the above-described operation. For example, a conventional technique discussed in Japanese Patent Application Laid-Open No. 11-214287 automatically repeats a mark detection operation if an initial field of the camera fails to detect a mark. 
         [0007]    According to the above-described conventional technique, an operator manually searches an alignment mark while moving (operating) a mask stage or a wafer stage displayed on an operation screen of a computer terminal associated with an exposure apparatus. Therefore, an operator performing an alignment mark search work is required to stay in the vicinity of the exposure apparatus. 
         [0008]    For example, if an operator performs remote control of an exposure apparatus from an on-line host computer, the operator necessarily goes to a place where the exposure apparatus is installed when the operator performs an alignment mark search work. Therefore, the work efficiency is not good. 
         [0009]    Furthermore, a plurality of exposure apparatuses may use a common reticle if the exposure apparatuses manufacture semiconductor devices of the same pattern. In this case, if the automatic alignment processing for a reticle or a wafer is failed, an operator is required to frequently perform a manual alignment mark search work. 
         [0010]    However, according to the above-described conventional technique, an operator is required to start a manual alignment search operation from the beginning each time the automatic alignment processing is failed, even if the manual alignment of some reticles or wafers is already finished. Thus, the work efficiency is deteriorated. 
       SUMMARY OF THE INVENTION 
       [0011]    Exemplary embodiments of the present invention are directed to improvement of the work efficiency in a mark search operation. 
         [0012]    According to an aspect of the present invention, an exposure apparatus configured to measure a position of at least one of a mark formed on an original plate and a mark formed on a substrate and to expose the substrate to radiant energy based on the measured position includes a stage configured to hold one of the original plate and the substrate and to be moved, a scope configured to capture an image of the mark formed on one of the original plate and the substrate held by the stage, an input unit configured to be operated to instruct a position of the stage, a display, and a controller configured to combine images respectively captured by the scope at a plurality of positions of the stage instructed by the input unit into a combined image and to cause the display to display the combined image. 
         [0013]    According to another aspect of the present invention, an operation apparatus is configured to operate an exposure apparatus, wherein the exposure apparatus includes a stage configured to hold one of an original plate and a substrate and to be moved and a scope configured to capture an image of a mark formed on one of the original plate and the substrate held by the stage, measures a position of the mark, and exposes the substrate to radiant energy based on the measured position. The operation apparatus includes an input unit configured to be operated to instruct a position of the stage, a display, and a controller configured to combine images respectively captured by the scope at a plurality of positions of the stage instructed by the input unit into a combined image and to cause the display to display the combined image. 
         [0014]    According to yet another aspect of the present invention, a computer-readable medium is provided including computer-executable instructions stored in a computer-readable medium for operating an expose exposure apparatus including a stage configured to hold one of an original plate and a substrate and to be moved and a scope configured to capture an image of a mark formed on one of the original plate and the substrate held by the stage, wherein the expose exposure apparatus measures a position of the mark and exposes the substrate to radiant energy based on the measured position. The medium includes computer-executable instructions for receiving information instructing a position of the stage from an input unit, computer-executable instructions for combining images respectively captured by the scope at a plurality of instructed positions of the stage into a combined image, and computer-executable instructions for causing a display to display the combined image. 
         [0015]    According to yet another aspect of the present invention, a method for manufacturing a device includes exposing a substrate to radiant energy using the above-described exposure apparatus, developing the exposed substrate, and processing the developed substrate to manufacture the device. 
         [0016]    Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain at least some of the principles of the invention. 
           [0018]      FIG. 1  illustrates an example configuration of an exposure apparatus according to a first exemplary embodiment of the present invention and an example configuration of a computer terminal that manages the exposure apparatus. 
           [0019]      FIG. 2  illustrates an example search operation screen displayed on a display unit of the computer terminal according to the first exemplary embodiment. 
           [0020]      FIG. 3  illustrates an example data structure of local area network (LAN) transmission data transmitted between the computer terminal and the exposure apparatus during an alignment mark search operation according to the first exemplary embodiment. 
           [0021]      FIG. 4  illustrates an example setting screen displayed when an operator presses a setting screen start button located in a button display field of the search operation screen according to the first exemplary embodiment. 
           [0022]      FIG. 5  illustrates an example mark setting screen according to a second exemplary embodiment of the present invention, which can be displayed when an operator presses a mark setting screen start button. 
           [0023]      FIG. 6  illustrates an example of a search history file including search information obtained using the search operation screen according to the second exemplary embodiment. 
           [0024]      FIG. 7  illustrates an example of a search history screen according to the second exemplary embodiment, which can be displayed when an operator presses a search history screen start button. 
           [0025]      FIG. 8  illustrates an example of a search operation screen according to the second exemplary embodiment, which can be displayed when an operator presses a history read button on the search history screen. 
           [0026]      FIG. 9  is a flowchart illustrating a device manufacturing method that uses the exposure apparatus according to an exemplary embodiment of the present invention. 
           [0027]      FIG. 10  is a flowchart illustrating details of a wafer process in the flowchart of  FIG. 9 . 
           [0028]      FIG. 11  is a flowchart illustrating a procedure of processing performed by a computer terminal according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0029]    The following description of exemplary embodiments is illustrative in nature and is in no way intended to limit the invention, its application, or uses. It is noted that throughout the specification, similar reference numerals and letters refer to similar items in the following figures, and thus once an item is described in one figure, it may not be discussed for following figures. Exemplary embodiments of the present invention are described below with reference to the attached drawings. 
       First Exemplary Embodiment 
       [0030]      FIG. 1  illustrates an example of a configuration of an exposure apparatus  100  according to a first exemplary embodiment of the present invention and an example of a configuration of a computer terminal  121  that manages the exposure apparatus  100 . In  FIG. 1 , the exposure apparatus  100  is structurally similar to other exposure apparatuses  118  and  119 . The exposure apparatuses  100 ,  118 , and  119  are connected to the computer terminal  121  via a local area network (LAN)  120 . The exposure apparatus  100  includes a console control unit  115 , which, for example, includes a central processing unit (CPU) and a random access memory (RAM), which is an internal memory. 
         [0031]    The console control unit  115  controls a display unit  108 , such as a cathode ray tube (CRT) or a liquid crystal display, and recognizes an input signal received from an input unit  107 , such as a keyboard, a mouse, or a touch panel. Furthermore, the console control unit  115  controls a storage device  116 , which is a storage unit, such as a hard disk or a magneto-optical disk (MO). 
         [0032]    Furthermore, the console control unit  115  controls a LAN transmission/reception unit  117  connected to the LAN  120  (i.e., an information network in a factory), an illumination control unit  109 , an A-scope control unit  110 , and a mask stage control unit  111 . Furthermore, the console control unit  115  controls a B-scope control unit  112 , a wafer stage control unit  113 , and an image input unit  114 . 
         [0033]    Particularly, the console control unit  115  transmits predetermined control commands to the illumination control unit  109 , the A-scope control unit  110 , and the mask stage control unit  111 , thereby controlling the exposure apparatus  100 . The mask stage control unit  111  is configured to control a mask stage  102 . The wafer stage control unit  113  is configured to control a wafer stage  104 . 
         [0034]    The illumination control unit  109  receives a control command from the console control unit  115  and controls an illumination unit  101 , which is configured to emit exposure light. The A-scope control unit  110  receives a control command from the console control unit  115  and controls an A-scope  105 . The A-scope  105  is a microscope capable of observing an alignment mark on a mask (circuit pattern mask) in an alignment operation of the mask. The A-scope  105  can transmit a video signal representing a captured image of the mark to the image input unit  114 . 
         [0035]    The mask stage control unit  111  receives a control command from the console control unit  115  and controls the movement of the mask stage  102  in an XYZ coordinate system. Thus, the mask stage control unit  111  can adjust a projection position of the mask during exposure processing. The A-scope  105  functions as a mask alignment image capturing unit. 
         [0036]    The B-scope control unit  112  receives a control command from the console control unit  115  and controls a B-scope  106 . The B-scope  106  is a microscope capable of observing an alignment mark on a wafer (semiconductor wafer) in an alignment operation of the wafer. The B-scope  106  can transmit a video signal representing a captured image of the wafer to the image input unit  114 . 
         [0037]    The wafer stage control unit  113  receives a control command from the console control unit  115  and controls the movement of the wafer stage  104  in an XYZ coordinate system. Thus, the wafer stage control unit  113  can adjust an exposure position of the wafer during exposure processing. A projection lens  103  is necessary when a reduced pattern of the mask is printed on the wafer. The B-scope  106  functions as a wafer alignment image capturing unit. 
         [0038]    The image input unit  114  receives video signals from the A-scope  105  and the B-scope  106  and stores the received video signals in its internal image memory. The image input unit  114  outputs the video signals to the console control unit  115 . In this case, the console control unit  115  receives a video signal from the A-scope  105  when the alignment object is the mask stage  102  and receives a video signal from the B-scope  106  when the alignment object is the wafer stage  104 . 
         [0039]    The console control unit  115  converts, at predetermined time intervals, a received video signal into still images and stores the still images in its internal memory. Then, the console control unit  115  generates transmission data including identification information of the exposure apparatus  100  and positional information of the imaging object in addition to the still images stored in the internal memory. Furthermore, the console control unit  115  transmits the transmission data to the LAN transmission/reception unit  117 , which can communicate with an external apparatus via the LAN  120 . 
         [0040]    The computer terminal  121  is an operation terminal that enables an operator to perform a search operation of an alignment mark. The computer terminal  121  can communicate with each of the exposure apparatuses  100 ,  118 , and  119  via the LAN  120 . Hereinafter, the computer terminal  121  is referred to as an external computer terminal  121 . The external computer terminal  121  can be installed in a clean room together with the exposure apparatuses  100 ,  118 , and  119 , or can be installed in another room. 
         [0041]    The external computer terminal  121  includes a display screen control unit  125 , which controls a display unit  123 , such as a CRT or a liquid crystal display. Furthermore, the external computer terminal  121  recognizes a signal received from an input unit  122 , such as a keyboard or a mouse, and controls a storage device  126 , such as a hard disk or an MO. 
         [0042]    Furthermore, the display screen control unit  125  controls a LAN transmission/reception unit  124 , which is connected to the LAN  120  (i.e., an information network in a factory). The LAN transmission/reception unit  124  receives LAN transmission data from the exposure apparatus  100 . The display screen control unit  125  analyzes the received LAN transmission data. The display screen control unit  125  generates a search operation image  127  (i.e., a search result of an alignment mark) from the analysis information of the LAN transmission data. The display unit  123  displays the search operation image  127 . The display screen control unit  125  and the search operation image  127  function as a unit configured to detect an alignment mark of a mask (circuit pattern mask) or a wafer (semiconductor wafer). 
         [0043]      FIG. 2  illustrates an exemplary search operation screen displayed on the display unit  123  of the external computer terminal  121 . The search operation image  127  displayed on the display unit  123  corresponds to a search operation screen  200  illustrated in  FIG. 2 . A state display field  201  positioned at an upper part of the search operation screen  200  includes an apparatus information display field  202 , which displays apparatus information identifying the exposure apparatus  100 , which is a search object. 
         [0044]    The state display field  201  further includes an alignment information display field  203 , which displays an alignment type that requires a re-search operation due to failure in a mark search operation performed by the exposure apparatus  100  or information on a target stage (a drive object) identified by the search. 
         [0045]    The state display field  201  further includes a material information display field  204 , which displays identification information of a search object, such as a lot, a wafer, or a mask. The state display field  201  further includes an imaging position display field  205 , which displays positional information of an imaging object, such as a wafer or a mask. 
         [0046]    The information content displayed in each of the alignment information display field  203 , the material information display field  204 , and the imaging position display field  205  reflects the analysis on the information contained in the LAN transmission data received from the exposure apparatus  100  via the LAN  120 . 
         [0047]    Namely, the display unit  123  receives an analysis result from the display screen control unit  125 , and displays the analysis result in the alignment information display field  203 , the material information display field  204 , or the imaging position display field  205  of the state display field  201 . The display unit  123  updates the positional information of an imaging object displayed in a captured image display field  213  every time the imaging object moves. The captured image display field  213  displays a captured image analyzed by the display screen control unit  125  based on captured image data involved in the LAN transmission data received from the exposure apparatus  100  via the LAN  120 . 
         [0048]    The display unit  123  continuously receives still images captured by the A-scope  105  and the B-scope  106  (involved in the LAN transmission data) and displays each received image in the captured image display field  213 . Therefore, an operator viewing the captured image display field  213  can observe the image images as a real-time moving image of the mask stage  102  or the wafer stage  104 . 
         [0049]    The captured image display field  213  can display any other image, such as an auxiliary scale  214  that indicates a central coordinate of a captured image, superimposed on a captured image involved in the LAN transmission data. 
         [0050]    The search operation screen  200  includes a moving operation unit that enables an operator to change the position of an imaging object displayed in the captured image display field  213 . The moving operation unit is, for example, a direction button functioning as an image interface or a manual input unit that enables an operator to directly input position coordinates of a destination. For example, if an operator presses (clicks) a direction button of a stage driving direction operation field  217 , the position of an imaging object of the mask stage  102  or the wafer stage  104  moves in the designated direction by a distance being set in a stage direction drive distance input field  216 . 
         [0051]    If the moving operation unit allows an operator to directly input position coordinates of a destination, the captured image display field  213  displays an image captured at an XY-coordinate position being set in a drive position input field  219 . The moving operation unit includes a drive position input mode switching button  218 . The drive position input mode switching button  218  enables an operator to select an absolute coordinate input mode or a relative coordinate input mode. 
         [0052]    If an operator presses a stage drive operation button  220  in the absolute coordinate input mode, the captured image display field  213  displays images of the mask stage  102  and the wafer stage  104  captured at positions set in the drive position input field  219 . Furthermore, if an operator presses the stage drive operation button  220  in the relative coordinate input mode, the captured image display field  213  displays images of the mask stage  102  and the wafer stage  104  captured at positions obtained by adding set values in the drive position input field  219  to the present imaging positions. 
         [0053]    Furthermore, if an operator operates the stage driving direction operation field  217  or presses the stage drive operation button  220 , the display screen control unit  125  generates a stage drive request command. The stage drive request command includes a stage driving amount being set by an operator through the stage driving direction operation field  217  or the stage drive operation button  220 . The LAN transmission/reception unit  124  transmits the stage drive request command to the exposure apparatus  100  via the LAN  120 . In the exposure apparatus  100 , the LAN transmission/reception unit  117  receives the stage drive request command transmitted from the external computer terminal  121 . The console control unit  115  receives the stage drive request command from the LAN transmission/reception unit  117 . 
         [0054]    The console control unit  115  determines a target stage (i.e., a drive object) based on drive object stage information included in the stage drive request command. The console control unit  115  generates an actual stage drive command corresponding to the stage driving amount contained in the stage drive request command. The console control unit  115  transmits the actual stage drive command to the mask stage control unit  111  or the wafer stage control unit  113  according to the determined target stage. The mask stage control unit  111  or the wafer stage control unit  113  receives the actual stage drive command and drives the mask stage  102  or the wafer stage  104 . 
         [0055]    Accordingly, the imaging position of the mask stage  102  captured by the A-scope  105  and the imaging position of the wafer stage  104  captured by the B-scope  106  relatively move. The A-scope  105  and the B-scope  106  generate video signals having different imaging contents. 
         [0056]    Therefore, the console control unit  115  generates LAN transmission data including video signals from the A-scope  105  and the B-scope  106  reflecting the mask stage  102  and the wafer stage  104  having been moved. The LAN transmission/reception unit  117  transmits the LAN transmission data to the external computer terminal  121  via the LAN  120 . Thus, the external computer terminal  121  receives the LAN transmission data including images of the mask stage  102  and the wafer stage  104  having been moved in response to an operator&#39;s input via the stage driving direction operation field  217  or the stage drive operation button  220 . 
         [0057]    The operation of the external computer terminal  121  includes continuously performing the above-described moving instruction and displaying an image of the mask stage  102  or the wafer stage  104  having been moved again. Therefore, an operator of the external computer terminal  121  can observe an image displayed in the captured image display field  213  as a real-time image of the mask stage  102  or the wafer stage  104  of the exposure apparatus  100 . 
         [0058]    Furthermore, even when an alignment mark is not recognized when a search operation is started, the alignment mark appears as an alignment mark  215  in the captured image display field  213  as a result of the performed search operation. The above-described operation can be performed similarly in both the above-described absolute coordinate input mode and the relative coordinate input mode. 
         [0059]    The state display field  201 , the stage driving direction operation field  217 , the drive position input field  219 , and the stage drive operation button  220  of the search operation screen  200  constitute an alignment mark search operation unit. In the first exemplary embodiment, the display screen control unit  125  of the external computer terminal  121  and the search operation screen  200  (mainly, the captured image display field  213 )) constitute a composite image generation unit. 
         [0060]      FIG. 3  illustrates an exemplary data structure of the LAN transmission data transmitted between an external computer terminal  301  and an exposure apparatus  300  during an alignment mark search operation. The LAN transmission data includes information  303 ,  304 , and  305  sectioned in Time  1 , Time  2 , and Time  3 . LAN transmission data  304  in Time  2  includes imaging object information  306 , such as apparatus information and imaging position. 
         [0061]    Furthermore, the LAN transmission data includes a still image  307  generated by the console control unit  115  converting a video signal captured by the A-scope  105  or the B-scope  106 . The external computer terminal  301  ( 121 ) continuously displays a still image on its operation screen based on still image information contained in the LAN transmission data, which is updated at predetermined time intervals. Thus, an operator of the external computer terminal  301  ( 121 ) can observe the image as a moving image. 
         [0062]    The console control unit  115  continuously generates LAN transmission data and outputs the generated data to the LAN transmission/reception unit  117 . However, if the stage drive request is not received from the external computer terminal  301  ( 121 ), the A-scope  105  and the B-scope  106  capture unchanged stage positions. In this case, the console control unit  115  stops transmitting LAN transmission data to the LAN transmission/reception unit  117 . Thus, the captured image display field  213  of the search operation screen  200  displays an image based on the latest LAN transmission data transmitted last from the exposure apparatus  300  ( 121 ). In this manner, if the imaging objects captured by the A-scope  105  and the B-scope  106  do not change their positions, the console control unit  115  interrupts transmitting image data via the LAN  302  ( 120 ) and, therefore, can reduce a total amount of data transmitted via the LAN  302 . 
         [0063]      FIG. 4  illustrates an exemplary setting screen  400 , which can be displayed when an operator presses a setting screen start button  210  positioned in a button display field  206  of the search operation screen  200 . The setting screen  400  includes an apparatus information input field  404 , which enables an operator to set identification information (e.g., apparatus name, type name, etc.) of an operation object (e.g., the exposure apparatus  100 ). 
         [0064]    The setting screen  400  further includes an apparatus network address input field  405 , which enables an operator to input network address information identifying an operation object (e.g., the exposure apparatus  100 ) selected from a plurality of exposure apparatuses connected to the LAN  120 . The setting screen  400  further includes a button display field  401 , which displays a setting finalization button  402  and a setting cancellation button  403 . 
         [0065]    An operator can instruct, by pressing the setting finalization button  402 , initiating an operation for designating the apparatus in the apparatus network address input field  405  as a search object. More specifically, the LAN transmission/reception unit  117  of the search object (the apparatus designated in the apparatus network address input field  405 ) communicates with the LAN transmission/reception unit  124  of the external computer terminal  121 . 
         [0066]    When there are a plurality of exposure apparatuses  100 ,  118 , and  119  connected to the LAN  120  as illustrated in  FIG. 1 , the apparatus network address input field  405  enables an operator to easily switch the operation object of the search screen by changing the contents in the field  405 . As described above, the external computer terminal  121  can display an image as a real-time image captured by an alignment camera of the exposure apparatus  100 . 
         [0067]    According to the above-described arrangement that enables an operator of the external computer terminal  121  to control the mask stage  102  and the wafer stage  104 , an on-line system operator can remotely control the exposure apparatus  100  placed in a clean room. A remote-control operator is not required to approach the exposure apparatus  100  or wear a clean suit for a clean room. Thus, the work efficiency in an alignment mark search operation can be improved greatly. Furthermore, the external computer terminal  121  is configured to enable an operator to switch an alignment assist operation object (e.g., the exposure apparatus  100 ). Therefore, each exposure apparatus does not require a dedicated alignment assist operation terminal. The total cost can be reduced greatly. 
       Second Exemplary Embodiment 
       [0068]    Next, a second exemplary embodiment of the present invention is described based on the above-described arrangement of the first exemplary embodiment. The search operation screen  200  according to the second exemplary embodiment can be displayed by the external computer terminal  121  as described in the first exemplary embodiment or can be displayed by the display unit  108  of the exposure apparatus  100 . 
         [0069]    The following processing can be executed by the console control unit  115 , which controls the display unit  108  of the exposure apparatus  100 , or can be executed by the display screen control unit  125 , which controls the display unit  123  of the external computer terminal  121 . 
         [0070]    As illustrated in  FIG. 2 , the search operation screen  200  includes a composite image display field  221 , which displays a composite image  224  as a combination of images displayed in the captured image display field  213  corresponding to a plurality of imaging positions after a search is started. The display screen control unit  125  of the external computer terminal  121  and the search operation screen  200  (mainly, the composite image display field  221 ) constitute a composite image generation unit. 
         [0071]    The composite image display field  221  further displays an imaging area frame  225  that indicates a rectangular area currently displayed in the captured image display field  213 . The imaging area frame  225  enables an operator to easily check a positional relationship between the composite image  224  and an imaging position of the captured image display field  213 . Thus, the display of the imaging area frame  225  is effective to reduce unnecessary search operations for already searched regions. The composite image display field  221  includes a display scaling scroll bar  223  that enables an operator to magnify or reduce an image in the composite image display field  221 . 
         [0072]    When a magnified image is displayed in the composite image display field  221  according to an operation using the display scaling scroll bar  223 , the composite image display field  221  may display only a part of the composite image  224 . In this case, an operator can perform the following operations. 
         [0073]    If the external computer terminal  121  displays the composite image  224 , an operator can press a cursor key of the input unit  122  to move the position of the composite image  224  displayed in the composite image display field  221 . If the exposure apparatus  100  displays the composite image  224 , an operator can press a cursor key of the input unit  107  to move the position of the composite image  224  displayed in the composite image display field  221 . 
         [0074]    When an alignment mark is discovered as a result of search, a mark icon  226  can be put on the composite image  224  as information memorizing the position of the alignment mark. An operator can add the mark icon  226  to the composite image  224  on a mark icon setting screen  500  (see  FIG. 5 ), which is described below later. A mark list  227  displays a list of mark icons  226  added to the composite image  224 . The mark list  227  displays identification information of the mark icon  226 , which includes the shape/type of each alignment mark, position coordinates of the mask stage  102  or the wafer stage  104  to which the mark icon  226  is attached, and comments. 
         [0075]    The display screen control unit  125  and the mark icon  226  constitute an addition unit configured to add, to the composite image  224 , an alignment mark shape and coordinate information of the mask stage  102  or the wafer stage  104 . Furthermore, the addition unit includes the mark list  227  and the mark icon setting screen  500 . 
         [0076]    The button display field  206  of the search operation screen  200  displays a search history save button  207 , a mark setting screen start button  208 , a mark position applying button  209 , the setting screen start button  210 , a search history screen start button  211 , and an operation screen closure button  212 . 
         [0077]    If an operator presses the search history save button  207 , a search history file  600  (refer to  FIG. 6 ) is generated based on search information obtained using the search operation screen  200 . The storage device  116  or  126  stores each generated search history file  600 . The search history file  600  includes file identification information  601  (e.g., file generation time and comment) and apparatus information  602  (e.g., apparatus name and apparatus type number of a search object). 
         [0078]    The search history file  600  further includes alignment information  603  (e.g., alignment type and drive object stage) and material information  604  (e.g., lot number and wafer number of a search object). 
         [0079]    The search history file  600  further includes mark information  605  (e.g., information of the mark list  227  added below the composite image display field  221  on the search operation screen  200 ) and composite image information  606  (i.e., image data in the composite image display field  221  of the search operation screen  200 . 
         [0080]    If an operator presses the mark setting screen start button  208 , the composite image display field  221  displays the mark icon setting screen  500  illustrated in  FIG. 5 . If an operator presses the mark position applying button  209 , the drive position input field  219  displays positional information of the mark selected from the mark list  227 . If an operator presses the mark position applying button  209  in a state where a selection state mark  228  is present in the mark list  227 , the drive position input field  219  displays coordinate information of the selection state mark  228 . 
         [0081]    If an operator presses the mark position applying button  209  and the stage drive operation button  220  successively, the captured image display field  213  displays an image including a mark position. If an operator presses the search history screen start button  211 , the display unit  108  or  123  displays a search history screen  700  including a list of search history files  600  read from the storage device  116  or  126 . The mark setting screen start button  208 , the mark position applying button  209 , the drive position input field  219 , and the stage drive operation button  220  constitute part of the addition unit. An operator can close the search operation screen  200  by pressing the search screen closure button  212 . 
         [0082]    The following screens are displayed when an operator presses buttons included in the button display field  206 .  FIG. 5  illustrates an example of the mark icon setting screen  500  displayed when an operator presses the mark setting screen start button  208 . The following processing can be executed by the console control unit  115 , which controls the display unit  108  of the exposure apparatus  100 , or by the display screen control unit  125 , which controls the display unit  123  of the external computer terminal  121 . 
         [0083]    As illustrated in  FIG. 5 , the mark icon setting screen  500  includes an alignment mark input field  504 , which enables an operator to designate the shape/type of an alignment mark (a mark icon) added to the composite image  224 . The alignment mark input field  504  can display a plurality of alignment marks and enables an operator to select a desired alignment mark. 
         [0084]    The mark icon setting screen  500  further includes a mark icon display field  505 , which displays an image corresponding to the alignment mark selected in the alignment mark input field  504 . The mark icon setting screen  500  further includes a comment input field  506 , which enables an operator to input comment information identifying a mark. The mark icon setting screen  500  further includes a button display field  501 , which displays a mark addition button  502  and a mark setting screen closure button  503 . The mark addition button  502  is an interface that adds alignment mark information input in the mark icon setting screen  500  to the composite image  224 . 
         [0085]    If an operator presses the mark addition button  502 , a mark icon appears on the composite image  224 . The mark icon indicates a position corresponding to the central position of the captured image display field  213  of the search operation screen  200 . Furthermore, the information (e.g., shape/type) of an alignment mark set on the mark icon setting screen  500  and coordinate information of the mask stage  102  or the wafer stage  104  indicated by the mark icon are added to the mark list  227 . 
         [0086]    By pressing the mark setting screen closure button  503 , an operator can discard any change added on the mark icon setting screen  500  and close the mark icon setting screen  500 . The mark icon display field  505  and the mark addition button  502  are constituent components of the addition unit. 
         [0087]      FIG. 7  illustrates an exemplary search history screen  700  displayed when an operator presses the search history screen start button  211 . The following processing can be executed by the console control unit  115 , which controls the display unit  108  of the exposure apparatus  100 , or by the display screen control unit  125 , which controls the display unit  123  of the external computer terminal  121 . 
         [0088]    As illustrated in  FIG. 7 , a search history list display field  704  displays a list of search history files  600  stored in the storage device  116  or  126 . Each row of the search history list display field  704  displays the contents of one search history file  600 . A history identification information display field  705  displays the file identification information  601  of the search history file  600 . An apparatus information display field  706  displays the apparatus information  602  of the search history file  600 . An alignment display field  707  displays the alignment information  603  of the search history file  600 . 
         [0089]    A material information display unit  708  displays the material information  604  of the search history file  600 . A mark information display unit  709  displays the mark information  605  of the search history file  600 . A composite image display field  710  displays a reduced image of the composite image information  606  of the search history file  600 . 
         [0090]    When the search history list display field  704  displays a list of past search history files  600 , an operator can easily check whether a present search object (i.e., a mask or a wafer) of the search operation screen  200  has ever been searched by any other exposure apparatus. 
         [0091]    The search history screen  700  includes a button display field  701 , which displays a history read button  702  and a history screen closure button  703 . The history read button  702  is an interface that enables an operator to load the history item  711  selected in the search history list display field  704  into the search operation screen  200 . The history screen closure button  703  is an interface that enables an operator to close the search history screen  700 . 
         [0092]      FIG. 8  illustrates an exemplary search operation screen  800 , which is displayed when an operator presses the history read button  702  on the search history screen  700 . The following processing can be executed by the console control unit  115 , which controls the display unit  108  of the exposure apparatus  100 , or by the display screen control unit  125 , which controls the display unit  123  of the external computer terminal  121 . 
         [0093]    If an operator switches to a search history display tab using a composite image display switching tab  808  in a state where the search operation screen  800  displays a readout search history as illustrated in  FIG. 8 , a composite image display field  809  displays the following information. The composite image display field  809  displays a composite image  810 , which is included in the selection state history  711  selected on the search history screen  700 , together with a mark icon  811  and a mark list  813 . 
         [0094]    Furthermore, the composite image display field  809  displays an imaging area frame  812  that represents an imaging area of a captured image display field  804  that displays a real-time image. The search operation screen  800  simultaneously displays a real-time image captured by the A-scope  105  or the B-scope  106  displayed in the captured image display field  804  and a composite image  810  of past searched images displayed in the composite image display field  809 . 
         [0095]    Therefore, an operator can effectively perform a search operation by referring to the past search history without repetitively searching the same position. Furthermore, if the captured image display field  804  displays the position of a mark icon included in the search history, the following procedure becomes feasible. 
         [0096]    More specifically, an operator selects a history tab with the composite image display switching tab  808  and selects an intended mark (e.g., a selection state mark  814 ) from the mark list  813 , then presses a mark position applying button  802 . 
         [0097]    Then, a drive position input field  806  displays mark coordinates included in the selection state mark  814 . Furthermore, if an operator presses a stage drive operation button  807  in a state where the positional information of the selection state mark  814  is set in the drive position input field  806 , the captured image display field  804  displays the following information. 
         [0098]    More specifically, the captured image display field  804  displays images obtained by the A-scope  105  and the B-scope  106  capturing the positions of the mask stage  102  and the wafer stage  104  indicated by mark icons having been set previously. As described above, the display unit  108  of the exposure apparatus  100  or the display unit  123  of the external computer terminal  121  can simultaneously display an image captured by the A-scope  105  or the B-scope  106  and a composite image of images indicating the mask stage position or wafer stage position. 
         [0099]    Thus, an operator can check a positional relationship between the search path and a displayed captured image and can reduce operation errors without repeatedly searching the same place. The work efficiency can be improved greatly. 
         [0100]    Furthermore, an operator can record a history of a composite image and mark information added to the image, and also can easily perform a re-search operation for a mask or a wafer that has ever been subjected to an alignment mark search operation performed by the same exposure apparatus or another exposure apparatus. 
         [0101]    Namely, an operator can shorten a manual alignment mark search operation (does not need to start the operation from the beginning) because the history information is available. Therefore, the work efficiency can be improved greatly. 
         [0102]      FIG. 11  is a flowchart illustrating a procedure of processing performed by the computer terminal  121  based on a program according to an exemplary embodiment of the present invention. Note that the program can also be executed by the console control unit  115  of the exposure apparatus  100 . 
         [0103]    In step S 901 , the external computer terminal  121  displays the search operation screen  200  illustrated in  FIG. 2  on the display unit  123 . 
         [0104]    In step S 902 , the external computer terminal  121  analyzes the LAN transmission data received from the exposure apparatus  100 ,  118 , or  119  via the LAN  120 . 
         [0105]    In step S 903 , the state display field  201  of the search operation screen  200  displays an analysis result of the LAN transmission data. The captured image display field  213  displays an image. For example, the state display field  201  including corresponding display fields successively displays apparatus information, alignment information, material information, and imaging positional information of the exposure apparatus  100 ,  118 , or  119  based on the analysis result. Furthermore, the captured image display field  213  successively displays images captured by the A-scope  105  or the B-scope  106  in the exposure apparatus  100 ,  118 , or  119 . 
         [0106]    In step S 904 , the composite image display field  221  of the search operation screen  200  displays the composite image  224  as a combination of images displayed in the captured image display field  213  corresponding to a plurality of imaging positions after a search is started. Namely, the external computer terminal  121  generates a composite image including image information obtained from the exposure apparatus  100  with reference to the imaging position of at least one of the mask stage  102  and the wafer stage  104  and displays the generated composite image in the composite image display field  221 . 
         [0107]    The composite image display field  221  displays the imaging area frame  225 , which indicates a rectangular area currently displayed in the captured image display field  213 . Thus, an operator can easily check a positional relationship between the composite image  224  and a captured image in the captured image display field  213 . Furthermore, an operator can magnify or reduce the image in the composite image display field  221  by operating the display scaling scroll bar  223 . 
         [0108]    If the scaling adjustment with the display scaling scroll bar  223  causes any undesirable result, an operator can operate the cursor key of the input unit  122  to move the position of the composite image  224  in the composite image display field  221 . The mark icon  226  added to the composite image  224  is information memorizing the position of the alignment mark discovered as a result of search. 
         [0109]    In step S 905 , an operator can add the mark icon  226  to the composite image  224  using the mark icon setting screen  500 . The mark list  227  for the composite image  224  displays a list of mark icons  226  added to the composite image  224 . The external computer terminal  121  adds further information to the composite image  224 . The information added to the composite image  224  includes shape information of an alignment mark attached to at least one of a mask and a wafer and coordinate information including coordinates of at least one of the mask stage  102  and the wafer stage  104 . 
         [0110]    In step S 906 , based on the analysis result, the external computer terminal  121  determines whether there is any exposure apparatus that has failed in the alignment mark search operation. If there is no exposure apparatus that has failed in the alignment mark search operation (NO in step S 906 ), the external computer terminal  121  terminates the processing of this routine. On the other hand, if there is any exposure apparatus that has failed in the alignment mark search operation (YES in step S 906 ), the processing flow proceeds to step S 907 . 
         [0111]    In step S 907 , the state display field  201  displays the above-described information of the exposure apparatus that has failed in the alignment mark search operation or maintains the state of display if the above-described information is already displayed. The alignment information display field  203  displays an alignment type that requires a re-search operation due to failure in the mark search operation or information relating to a target stage (a drive object) identified by the search. Furthermore, the captured image display field  213  displays an image captured by the A-scope  105  or the B-scope  106  of the exposure apparatus that has failed in the mark search operation. 
         [0112]    In step S 908 , the external computer terminal  121  checks the presence of any instruction input via the button display field  206 , the stage driving direction operation field  217 , and the drive position input mode switching button  218  on the search operation screen  200 . 
         [0113]    For example, if in step S 908  the external computer terminal  121  recognizes a user&#39;s operation on any direction button in the stage driving direction operation field  217  in a condition where a moving distance is set in the stage direction drive distance input field  216 , the external computer terminal  121  performs the following processing. 
         [0114]    Namely, the external computer terminal  121  generates a stage drive request command for moving an imaging object (the mask stage  102  or the wafer stage  104 ) in the direction designated by the direction button and to the position designated by the moving distance having being set. Then, the external computer terminal  121  transmits the generated stage drive request command to the corresponding exposure apparatus. 
         [0115]    If in step S 908  the external computer terminal  121  recognizes any input of drive position in the drive position input field  219  and any operation on the stage drive operation button  220  in a condition where the drive position input mode switching button  218  selects the absolute coordinate input mode, the external computer terminal  121  performs the following processing. 
         [0116]    Namely, the external computer terminal  121  generates a stage drive request command for moving an imaging object (the mask stage  102  or the wafer stage  104 ) to the position designated by the input drive position (XY-drive position). Then, the external computer terminal  121  transmits the generated stage drive request command to the corresponding exposure apparatus. 
         [0117]    When the exposure apparatus receives a stage drive request command from the external computer terminal  121 , the exposure apparatus performs processing similar to that described in the first exemplary embodiment. 
         [0118]    In step S 909 , the captured image display field  213  displays an image of the imaging object moved to a new position, based on LAN transmission data transmitted from the exposure apparatus that has failed in the last mark search operation. Furthermore, step S 909  includes the above-described processing performed in step S 904  (i.e., displaying a composite image in the composite image display field  221 ). 
         [0119]    In step S 910 , the external computer terminal  121  analyzes the LAN transmission data transmitted from the exposure apparatus that has failed in the last mark search operation and determines whether the present alignment mark search operation is successful. 
         [0120]    If the alignment mark search operation performed by the exposure apparatus that has failed in the previous mark search operation is successful (YES in step S 910 ), the external computer terminal  121  determines the presence of any operation on the search history save button  207  of the button display field  206 . 
         [0121]    If any operation on the search history save button  207  is recognized, the external computer terminal  121  generates the search history file  600  based on the search information input on the search operation screen  200 . The storage device  126  stores the generated search history file  600 . If an operator presses the search history screen start button  211 , an image of each search history file  600  can be displayed. In this case, a captured image in the captured image display field  213 , which may include an alignment mark, and a composite image included in the search history information can be simultaneously displayed. 
         [0122]    However, if the present alignment mark search operation is failed (NO in step S 910 ), the external computer terminal  121  repeats the processing of steps S 908  to S 910 . 
         [0123]    Then, in step S 911 , the external computer terminal  121  determines whether there is any other exposure apparatus that has failed in the mark search operation. If there is any other exposure apparatus that has failed in the mark search operation (YES in step S 911 ), the processing flow returns to step S 908 . If there is no other exposure apparatus that has failed in the mark search operation (NO in step S 911 ), the processing flow proceeds to step S 912 . In step S 912 , the external computer terminal  121  determines the presence of any operation on the search screen closure button  212  in the button display field  206 . 
         [0124]    If an operator presses any button other than the search screen closure button  212 , the external computer terminal  121  performs the processing corresponding to the button operation as described in the second exemplary embodiment. However, if in step S 912  any operation on the search screen closure button  212  is recognized (YES in step S 912 ), the external computer terminal  121  terminates the processing of this routine. 
         [0125]    As described above, the program according to an exemplary embodiment enables an operator of the external computer terminal  121  to perform an alignment mark search operation while monitoring images of a mask and a wafer in the exposure apparatus  100  accessible via the LAN  120  from the external computer terminal  121 . 
         [0126]    Accordingly, an operator of an on-line host computer can manage each of a plurality of exposure apparatuses from a remote place and is not required to approach the exposure apparatus even if an alignment mark search operation is failed. Thus, the work efficiency can be improved greatly. 
         [0127]    Next, an exemplary device manufacturing method using the above-described exposure apparatus is described with reference to  FIGS. 9 and 10 .  FIG. 9  is a flowchart illustrating exemplary manufacturing processes for a semiconductor device (e.g., an integrated circuit (IC), a large scale integration (LSI), a liquid crystal display (LCD), and a charge-coupled device (CCD)). Step S 1  is a circuit design process for designing a circuit of a semiconductor device. Step S 2  is a mask making process for fabricating a mask, which can be referred to as an original plate or a reticle, based on a designed circuit pattern. 
         [0128]    Step S 3  is a wafer manufacturing process for manufacturing a wafer, which can be referred to as a substrate, from a silicon or comparable material. Step S 3  can be a reticle manufacturing process. Step S 4  is a wafer process, which can be referred to as “preprocess”, for forming an actual circuit on a wafer using an exposure apparatus with the above-described prepared mask according to the lithography technique. 
         [0129]    Step S 5  is an assembling process, which can be referred to as “postprocess”, for forming a semiconductor chip using the wafer manufactured in step S 4 . The postprocess includes an assembly process (e.g., dicing, bonding, etc.) and a packaging process (chip sealing). Step S 6  is an inspection process for inspecting the semiconductor device manufactured in step S 5 . The inspection includes an operation confirmation test and an endurance test. Step S 7  is a shipment process for shipping the semiconductor device completed through the above-described processes. 
         [0130]    As illustrated in  FIG. 10 , the above-described wafer process in step S 4  includes an oxidation step S 11  for oxidizing a wafer surface, a chemical vapor deposition (CVD) step S 12  for forming an insulating film on the wafer surface, and an electrode formation step S 13  for forming electrodes on the wafer by vaporization. Furthermore, the wafer process in step S 4  includes an ion implantation step S 14  for implanting ions into the wafer, a resist processing step S 15  for coating the wafer with a photosensitive material, and an exposure step S 16  for exposing the wafer subjected to the resist processing step to light using the above-described exposure apparatus with a mask having a circuit pattern. 
         [0131]    Furthermore, the wafer process in step S 4  includes a developing step S 17  for developing the wafer exposed in the exposure step S 16 , an etching step S 18  for cutting a portion other than a resist image developed in the developing step S 17 , and a resist stripping step S 19  for removing an unnecessary resist remaining after the etching step S 18 . The processing repeating the above-described steps can form multiple circuit patterns on a wafer. 
         [0132]    An exemplary device manufacturing method using the above-described exposure apparatus can improve the work efficiency in manufacturing a device and can increase the productivity of a device. As described above, the above-described exemplary embodiments can improve the work efficiency in a mark search operation. 
         [0133]    While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions. 
         [0134]    This application claims priority from Japanese Patent Application No. 2006-326378 filed Dec. 1, 2006, which is hereby incorporated by reference herein in its entirety.