JP2014153673A - Exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To defect the sensitivity of a substrate used for an exposure device at high precision.SOLUTION: In the exposure device provided with a light modulation element array in which micromirrors are arranged in a two-dimentional way, a plurality of mask patterns in which a micromirror service factor is gradually reduced are prepared. Then, every exposure operation, the mask patterns are successively switched to practice overlap exposure operations, and a step tablet pattern having a gradation where pattern concentration is continuously changed along a scanning direction is formed.

Description

  The present invention relates to an exposure apparatus that draws a pattern using a mask / reticle or directly draws a pattern using a spatial light modulation element such as a DMD (Digital Micro-mirror Device), and particularly relates to sensitivity detection of a photosensitive material.

  The sensitivity of the light-sensitive material varies depending on the type, and also varies with time. Therefore, it is necessary to detect the sensitivity of the photosensitive material before the drawing process and adjust the exposure conditions according to the sensitivity. Usually, adjustment work is performed using a step chart (sensitivity detection pattern) for sensitivity detection called a step tablet.

  Specifically, a step tablet is placed on the substrate, a drawing pattern is formed on the test surface from the step tablet, and a density level representing the sensitivity of the drawing pattern is examined. Then, the output of the light source and the like are adjusted so that the detected density level matches the reference density level as an index. After adjustment, the drawing process is executed.

  A step tablet is a transmission type step optical wedge (Transmission Step Wedge) in which a gray scale pattern with varying transmittance (density) in stages is drawn on a film sheet. Used as a gauge to detect and evaluate. In both the mask exposure apparatus and the maskless exposure apparatus, the exposure amount can be managed in accordance with the substrate using the step tablet.

  A commonly used step tablet is SRM (Standard Reference Material) No. 1 by NIST (National Institute of Standards and Technology). 1008, and is used for detecting sensitivity characteristics of a substrate (see, for example, Patent Document 1).

  On the other hand, in the case of a maskless exposure apparatus, instead of using a step tablet, it is possible to draw a sensitivity detection pattern directly on a photosensitive material. Specifically, a sensitivity detection pattern in which irradiation energy (pattern density) is increased stepwise is formed (see Patent Document 2). Alternatively, the sensitivity detection pattern is drawn by gradually increasing the dot pitch of a halftone dot image composed of a plurality of evenly distributed spot images (see Patent Document 3).

JP 2007-128015 A JP-A-2005-202226 JP 2007-11291 A

  The sensitivity of the photosensitive material varies depending on the type, and the detected sensitivity changes slightly depending on the exposure conditions such as light source characteristics. Since the conventional step tablet has a pattern in which constant density areas having a relatively large width are arranged stepwise, the detected density level may not exactly match the presented density level.

  Therefore, it is required to accurately detect the sensitivity of the photosensitive material used in the exposure apparatus.

  An exposure apparatus according to the present invention includes a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged, and an exposure area defined on a surface of a drawing object by the light modulation element array, continuously along a main scanning direction. And an exposure operation control unit that controls the plurality of light modulation elements in accordance with the relative position of the exposure region and forms a drawing pattern on the object to be drawn by an overlap exposure operation.

  While the exposure area moves relatively, the exposure operation control unit performs overlap exposure at a predetermined exposure pitch. That is, the multiple exposure operation is performed so that the exposure areas partially overlap each other. The exposure operation control unit can draw a step tablet in which a plurality of areas (hereinafter referred to as divided areas) are defined along the scanning direction. That is, the exposure operation control unit can form a step tablet pattern having a pattern density difference between a plurality of areas and in each divided area on the drawing object.

  As the pattern of the step tablet, it is possible to form a scale-like gradation pattern in which the irradiation energy, that is, the pattern density decreases or increases, or repeatedly increases and decreases along the scanning direction over the entire pattern.

  In the pattern of the step tablet of the present invention, an area having a constant total exposure amount is provided in stages, and the pattern is not a pattern for changing the total exposure amount for each area, but between adjacent divided areas and inside each divided area. There is a density difference. Such a pattern is realized by controlling a plurality of light modulation elements and overlapping exposure.

  For example, the exposure operation control unit can form a step tablet pattern in a blank area where a drawing pattern is not formed. In other words, a step tablet pattern is formed under the same conditions as the actual drawing process, and the drawing pattern is formed in the pattern formation region, thereby forming a drawing tablet step pattern for drawing management together with the drawing pattern on one substrate. can do. Based on this, the operator can manage the drawing process such as the amount of light.

  For example, the exposure operation control unit can form a step tablet pattern including an index pattern. This compares the reference and target sensitivity (exposure amount) position indicated by the index pattern with the position of the boundary line that forms the boundary between the exposed portion and the non-exposed portion when the actual step tablet pattern is formed. Thus, drawing management can be performed.

  The step tablet pattern may be displayed with a series of density patterns on a scale in which the number of steps is provided in a stepwise manner as in the case of the conventional step tablet. For example, the exposure operation control unit can synthesize a scale pattern and a series of mask patterns to form a step tablet pattern. In this case, a bar-shaped minute mask region that becomes a margin may be provided between adjacent divided areas, or a configuration may be employed in which no bar-like minute mask region is provided.

  As the pattern of the step tablet, the sensitivity can be easily detected by using a density pattern in which the pattern density generally decreases or increases along the scanning direction. For example, the light operation control unit can form a step tablet pattern in which the total exposure amount decreases or increases between adjacent divided areas and within each divided area.

  Further, a step tablet pattern in which density differences are provided stepwise in each divided area may be formed. In this case, a density pattern in which the density continues to increase / decrease over the entire divided area may be used, or a density pattern in which only a part of the density is constant may be provided.

  Alternatively, it is possible to form a stepless pattern in which the change rate of the total exposure amount is constant or gradually changes so that the pattern density can be regarded as continuously increasing or decreasing. The degree of density change of these density patterns can be performed by exposure pitch adjustment, switching control of a specific light modulation element, or the like.

  The exposure operation control unit forms a step tablet pattern by increasing or decreasing the number of unused light modulation elements that are not used during exposure in the light modulation element array according to the exposure operation. Can do. The number of non-uses may be changed in accordance with the exposure pitch, or may be switched at other pitch / time intervals.

  For example, overlap exposure is performed using a mask pattern that defines unused light modulation elements in the light modulation element array, and the exposure operation control unit gradually reduces the proportion of effective light modulation elements that are not unused. Alternatively, the plurality of increased mask patterns are sequentially switched and used in accordance with a predetermined mask switching pitch. The mask switching pitch may be the same as the exposure pitch or may be a pitch longer than the exposure pitch.

  The degree of change in the density of the step tablet pattern may be determined according to conditions such as the substrate to be used and its sensitivity characteristics. Sensitivity detection can be performed strictly by changing the concentration very slowly. For example, the exposure operation control unit can adjust the pattern length of the step tablet by changing the mask switching pitch. This changes the overall length of the overall scale (scaling width).

  The scale position formed in the pattern of the step tablet may be matched with the number of steps of the conventional step tablet. The exposure operation control unit can correct and adjust the scale position by changing the division area division position. That is, scaling is possible.

  The exposure operation control unit can form only a partial pattern of the step tablet. That is, only the density pattern near the target reference value can be formed by changing the start and end positions of the density pattern.

  According to another aspect of the present invention, there is provided an exposure method in which an exposure region defined on a surface of an object to be drawn is relatively moved along a main scanning direction by a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged. A method of controlling the plurality of light modulation elements according to a relative position of a region and forming a drawing pattern on an object to be drawn by an overlap exposure operation, wherein a pattern density difference between a plurality of divided areas and within each divided area A pattern of a step tablet having a pattern is formed on the drawing object.

  A program according to another aspect of the present invention is a program recorded on a computer-readable recording medium, and the exposure apparatus is placed on the surface of a drawing object by a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged. While the specified exposure area is relatively moved along the main scanning direction, the exposure position detecting means for detecting the exposure position, and the plurality of light modulation elements are controlled according to the relative position of the exposure area, and overlap exposure is performed. A program for functioning as an exposure operation control means for forming a drawing pattern on an object to be drawn by operation, wherein a pattern of a step tablet having a pattern density difference between a plurality of divided areas and within each divided area is represented by the object to be drawn It functions as the exposure operation control means.

  A step tablet according to another aspect of the present invention is a sensitivity detector corresponding to a transmission type stair optical wedge that can be used in both a mask exposure apparatus and a maskless exposure apparatus. The step tablet includes a scale in which numerical values corresponding to density levels are arranged, and a series of density patterns formed in a plurality of divided areas defined according to the scale, and the series of density patterns is between the divided areas. In addition, there is a gradation in which the transmittance decreases or increases in each divided area.

  According to the present invention, the sensitivity of the photosensitive material can be detected with high accuracy.

It is a block diagram of the exposure apparatus which is this embodiment. It is the figure which showed the sensitivity detection pattern. It is the graph which showed the change of the total exposure amount of a sensitivity detection pattern. It is the figure which showed the exposure amount distribution of each mask pattern. It is the figure which showed the total exposure amount distribution of the sensitivity detection pattern. It is the flowchart which showed the drawing process of the sensitivity detection pattern. It is the figure which showed the board | substrate which formed the step tablet pattern in 2nd Embodiment. It is the figure which showed the step tablet pattern and its production | generation process. It is the figure which showed a part of step tablet pattern. It is the flowchart which showed the drawing process of the step tablet pattern. It is the figure which showed the step tablet pattern which carried out scaling correction. It is the figure which showed the step tablet pattern which changed pattern length. FIG. 6 shows a partial step tablet pattern. It is the top view which showed the step tablet in 3rd Embodiment. It is the figure which showed the graph showing the transmittance | permeability of a step tablet.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of an exposure apparatus (drawing apparatus) according to this embodiment.

  The exposure apparatus 10 is a maskless exposure apparatus that directly forms a pattern on a substrate W coated or pasted with a photosensitive material such as a photoresist, and includes a DMD 22, an illumination optical system, and a projection optical system (both not shown). A pattern is formed by the exposure head 10A.

  The exposure apparatus 10 includes a discharge lamp 20 that emits illumination light such as ultraviolet light. The illumination light from the discharge lamp 20 is guided to the DMD 22 by the illumination optical system. The DMD 22 is a light modulation element array in which micro rectangular micromirrors of several μm to several tens of μm are two-dimensionally arranged in a matrix, and is configured by, for example, a 1024 × 768 micromirror.

  Each micromirror is ON / OFF controlled based on the exposure data. The light reflected by the micromirror in the ON state is guided to the substrate W through the projection optical system. As a result, the substrate W is irradiated with the light beam formed by the reflected light from the ON state mirror, that is, the pattern light. Although one DMD is shown here for explanation, a plurality of exposure heads are actually arranged.

  The drawing table 12 on which the substrate W is mounted is driven by the stage driving mechanism 14. The drawing table 12 defines an XY coordinate system orthogonal to each other, the drawing table 12 is movable along the X and Y directions, and the substrate feed direction is adjusted. Here, the X direction is defined as the main scanning direction (scanning direction SM), and the Y direction is defined as the sub-scanning direction.

  As the substrate W moves along the main scanning direction (X direction), a projection area defined by the DMD 22 (hereinafter referred to as an exposure area) moves relative to the substrate W. Here, a continuous movement method is employed as the movement method, and the exposure region moves relative to the substrate W at a constant speed. Further, a multiple exposure method is applied as an exposure method, and overlap exposure is performed at a predetermined exposure pitch (micromirror modulation time) while the drawing table 12 moves.

  By sequentially performing the exposure operation on each scanning band while shifting the substrate W in the sub-scanning direction (Y direction), a pattern is formed on the entire substrate. When the drawing process is completed, a post-process such as a development process, etching or plating, or a resist stripping process is performed to manufacture a substrate on which a pattern is formed.

  The controller 30 is connected to an external workstation (not shown) and controls the operation of the exposure apparatus 10. The control program is stored in a ROM (not shown) in the controller 30. The controller 30 outputs a control signal to the DMD driving circuit 24, the stage driving mechanism 14, and the like.

  The drawing data / pattern data input from the workstation to the controller 30 is vector data (CAD / CAM data) having drawing pattern position information, and position coordinate data based on the XY coordinate system defined for the substrate W. Represented as: The vector data input to the raster conversion circuit 26 is converted into raster data that is two-dimensional dot data (ON / OFF data).

  The raster data is read according to a control signal from an address control circuit (not shown), and is sent to the DMD driving circuit 24 via the exposure data generation circuit 28. The DMD driving circuit 24 performs ON / OFF control of each micromirror of the DMD 22 in accordance with a synchronization signal from the controller 30 based on the raster data sent as exposure data. While the drawing table 12 moves, the DMD 22 is controlled according to raster data corresponding to the relative position of the exposure area.

  The controller 30 controls the stage drive mechanism 14 via a drive circuit (not shown), thereby controlling the moving speed of the drawing table 12, the substrate feed direction, and the like. The position detection sensor 34 detects the position of the drawing table 12, that is, the relative position of the exposure area on the substrate W.

  In the preparatory stage before the exposure operation, the sensitivity detection pattern is formed on the substrate W in order to check the sensitivity of the photosensitive material of the substrate W and match it with the reference sensitivity at the time of exposure. The controller 30 reads data of a plurality of mask patterns stored in the memory 32 in accordance with an operation through an input device (not shown) from the operator, and outputs it to the exposure data generation circuit 28.

  In the exposure data generation circuit 28, exposure data is output according to the mask pattern, and overlap exposure is performed. Thereby, a sensitivity detection pattern is formed. At this time, the scanning speed is not changed and the lamp output is not adjusted.

The sensitivity detection pattern is a density gradation chart pattern corresponding to a transmission step tablet used in a mask exposure apparatus and a maskless exposure apparatus, and is represented by a series of density patterns. The operator adjusts the output of the discharge lamp 20 based on the drawn sensitivity detection pattern, and then executes normal drawing processing. Below, a sensitivity detection pattern is demonstrated using FIGS.

  FIG. 2 is a diagram showing a sensitivity detection pattern. FIG. 3 is a graph showing a change in the total exposure amount of the sensitivity detection pattern.

  As shown in FIG. 2, the sensitivity detection pattern SP is a pattern in which the pattern density, that is, the energy of light to be irradiated has gradation and a gradual change, and the pattern density becomes lighter as it proceeds in the main scanning direction. That is, when the entire pattern is viewed, the total exposure amount based on the multiple exposure in each minute region of the pattern decreases sequentially as the scanning direction proceeds. Hereinafter, the main scanning direction is referred to as a scanning direction SM.

  The sensitivity detection pattern SP is formed on the substrate W by repeating overlap exposure while moving the drawing table 12 at a constant speed, as in the actual drawing process. At this time, pattern data for turning on all the micromirrors is input to the raster conversion circuit 26, while in the exposure data generation circuit 28, some micromirrors are in the OFF state (not in accordance with the selected mask pattern). Use).

  As a result, when the sensitivity detection pattern SP is divided into small regions with respect to the scanning direction SM, the total exposure amount K gradually decreases over a range from the drawing start position to the end position (see FIG. 3). However, the total exposure amount K represents the total amount of light irradiated to the minute area in the process of overlap exposure. The change in the total exposure K is represented by the curve K, and the total exposure K changes substantially continuously.

  The range from the maximum to the minimum exposure amount K over the entire sensitivity detection pattern SP shown in FIGS. 2 and 3 is set as wide as possible in consideration of various sensitivity characteristics. When a sensitivity detection pattern is drawn on a substrate on which a photosensitive material having a specific sensitivity is formed, a boundary portion between a portion appearing as a pattern and a portion where the pattern does not appear is generated, and a lamp output or the like is adjusted based on this.

  FIG. 4 is a view showing an exposure amount distribution of each mask pattern. FIG. 5 is a diagram showing the total exposure amount distribution of the sensitivity detection pattern. The generation of the sensitivity detection pattern having the gradation of the total exposure amount will be described with reference to FIGS.

  Here, a period during which the exposure area EA moves by the same distance D as the area width J while the scanning speed is constant is defined as an exposure period. In this case, the total exposure amount of the line (small area) located at the leading edge of the exposure area EA is the largest, and the last edge of the exposure area EA at the start of scanning and the exposure area EA have moved by the distance D. The total amount of exposure at the tip side edge is minimized. Therefore, the total exposure amount distribution along the scanning direction in one exposure operation has a triangular shape.

  The plurality of mask patterns M0, M1, M2,... Prepared in advance are patterns in which unused micromirrors are scattered regularly or irregularly so as to uniformly reduce the irradiation light amount of the entire exposure region. It is prepared. The ratio of effective micromirrors that are not unused to all micromirrors for exposure is defined as the mirror usage rate. The lower the mirror usage rate, the lower the irradiation light quantity of the entire exposure area.

  The unused mirrors are distributed in a substantially uniform distribution with respect to the mirror area at substantially equal distance intervals. On the other hand, the unused mirrors are not regularly arranged when viewed from the entire mirror area. From a macro perspective, unused mirrors are evenly diffused. For example, unused micromirrors are scattered in a satin-like shape or a snow noise shape. Further, instead of employing an irregular array of unused mirrors, it is possible to employ a regular unused mirror array. For example, the unused mirrors can be arranged in a checkered pattern or a dot pattern, and the unused mirrors can be arranged at equal intervals.

  The mirror usage rate changes by adjusting the number of unused micromirrors and the arrangement of micromirrors that are not used. A series of mask patterns M1, M2, M3,... Is a combination of patterns in which the mirror usage rate gradually decreases, and the mask pattern M0 is a mask pattern with zero unused micromirrors, that is, a mirror usage rate of 100%. Determine.

  After the exposure with the mask pattern M0 is completed, the next exposure operation is executed with the mask pattern M1, and the next exposure operation is executed with the mask pattern M2. Then, the distribution of the total exposure amount is H0, H1, and H2, respectively, and the distribution shapes are different.

  As a result, the total exposure amount K decreases in the scanning direction SM, and the decrease rate changes each time the mask pattern is switched. FIG. 5 shows the total exposure amount K when the mask patterns M0, M1, M2, and M3 are sequentially used in accordance with the mask switching pitch P. The mask switching pitch P is set to a predetermined distance interval according to the required degree of gradation change (pattern density change rate) or the like.

  4 and 5 show the total exposure amount distribution when the mask switching pitch P is equal to the exposure region width J. The same can be said by making the mask switching pitch P shorter or longer than the exposure region width J. It is possible to have a gradation of the total exposure amount. Even in this case, the sensitivity detection pattern SP having the gradation of the total exposure amount K as shown in FIGS. 2 and 3 can be formed.

  FIG. 6 is a flowchart showing a sensitivity detection pattern drawing process.

  First, an initial mask pattern is read from the memory and an exposure operation is executed. Each time the exposure area moves by the mask switching pitch P, the mask pattern in which the mirror usage rate gradually decreases is sequentially switched and used. Such overlap exposure is repeated until the exposure operation with the last mask pattern is completed (S101 to S104).

  As described above, according to the present embodiment, a plurality of mask patterns in which the mirror usage rate gradually decreases is prepared, the mask patterns are sequentially switched every time the exposure operation is performed, and the overlap exposure operation is executed, along the scanning direction. A sensitivity detection pattern having a gradation in which the pattern density continuously changes is formed on the substrate.

  Since the sensitivity detection pattern is formed by using the micromirror under the same exposure conditions as in the actual drawing process without changing the lamp output and the scanning speed, it is possible to appropriately detect the sensitivity of the photosensitive material. Further, since gradation is formed by changing the total exposure amount by overlap exposure, it is possible to freely set the degree of gradation gradation change and the rate of change.

  Note that the sensitivity detection pattern may be a pattern in which the density is gradually increased, or a pattern in which increase and decrease are switched at an arbitrary position.

  Further, the mirror ON time may be adjusted instead of the exposure control for switching the mask pattern. In this case, when the ratio (ratio) of the exposure length (exposed distance) to the mask switching pitch is the scanning efficiency, the scanning efficiency is adjusted under the condition that all the microphone mirrors are turned on, that is, the mirror ON time is adjusted. Can control the pattern density.

  Next, an exposure apparatus according to the second embodiment will be described with reference to FIGS. In the second embodiment, a series of density patterns provided with a scale is formed as a sensitivity detection pattern in the same manner as the step tablet. Hereinafter, the sensitivity detection pattern is referred to as a step tablet pattern.

  FIG. 7 is a view showing a substrate on which a step tablet pattern is formed in the second embodiment. FIG. 8 is a diagram showing a step tablet pattern and its generation process.

  On the substrate W1, blank areas AP are provided on the upper and lower sides of the pattern area PP that is actually drawn, such as a circuit pattern. The step tablet pattern ST is formed in the margin area AP on the lower end side.

  The step tablet pattern ST displays a scale represented by the number of steps as in the conventional sheet-like step tablet, and a continuous density pattern is divided according to the scale position. Further, the total exposure amount and density level continue to decrease over the entire pattern. As shown in FIG. 8, the step tablet pattern ST is generated by synthesizing the scale pattern P1 on which the scale is displayed and the mask pattern set P2.

  The mask pattern set P2 includes a non-mask pattern that overlaps the scale portion of the scale pattern P1, and a continuous density pattern P2B corresponding to the sensitivity detection pattern shown in the first embodiment. A portion of the scale pattern P1 that overlaps the density pattern P2B is regularly formed with minute mask regions J that are separated according to the scale position.

  Therefore, the step tablet pattern ST is a continuous density pattern in which the continuous density pattern P2B is divided into a plurality of divided areas N. The density pattern J of each divided area N having a divided area J and an area width K between the divided areas has a gradation in which the total exposure amount continuously decreases. Each divided area density is not constant as in a conventional step tablet.

  The position of the scale indicating the number of steps is defined in accordance with, for example, the position of the density level corresponding to the number of steps of the conventional step tablet. The density corresponds to a logarithm of the reciprocal of the transmittance. Here, the density level is represented by a 30-stage scale.

  FIG. 9 is a diagram showing a part of the step tablet pattern ST.

  As described above, the step tablet pattern ST is divided into a region that appears as a pattern and a region that does not appear as a pattern due to the sensitivity characteristic of the photosensitive material formed on the surface of the substrate W1, and there is a boundary line. In FIG. 9, a boundary line appears between the stage number 18 and the stage number 19. The operator reads the position of the boundary line from the scale pattern scale. In the case of FIG. 9, the value of the boundary line is 18.4. It is determined from this numerical value whether or not it matches the target exposure amount.

  Since the step tablet pattern ST is a pattern in which the density level (total exposure amount) changes in the decreasing direction, the density level in the divided area of each number of stages can be further examined. That is, a density level finer than the number of stages can be examined. For example, if a table (not shown here) in which the density (total exposure amount) level that changes continuously and the position along the scanning direction of the density level are prepared in advance is detected, the detected boundary line A finer density level can be determined from the position of the.

  FIG. 10 is a flowchart showing a step tablet pattern drawing process.

  When a mask data number is set, a mask pattern corresponding to the number is read and set (S201 to S203). Then, the drawing start position and the start step number are set (S204, 205).

  When the drawing process is started, the drawing process using the first mask pattern is started (S205). In the exposure data generation circuit 28, the partial raster data of the scale pattern P1 corresponding to the mask pattern number and the mask pattern are synthesized.

  When the next exposure shot position is detected and it is determined that the exposure shot position has been reached, a mask pattern having a number corresponding to that position is set, and a partial scale pattern corresponding to the mask pattern is synthesized (S206). ~ S209). If the next step number is not the end number, the exposure operation using the next mask pattern is performed at the position moved by the mask switching pitch P (S210 to S212). When the exposure operation using the last mask pattern is executed, the drawing is finished (S213).

  Formation of a step tablet pattern by such drawing processing enables scaling correction, scale width correction, partial formation, and index display. This will be described below with reference to the drawings.

  FIG. 11 is a diagram showing a step tablet pattern that has undergone scaling correction.

  By changing the positions of the divisions regularly formed in the scale pattern shown in FIG. 8 and the display positions of the scales, the start and end positions of each density pattern can be arbitrarily set. Therefore, the scaling can be appropriately corrected according to the number of steps of the conventional step tablet.

  FIG. 11 shows a step tablet pattern ST1 in which the scale position and the dividing position of the number of steps are corrected. In order to perform such scale correction (scaling), when the scale pattern and the mask pattern are matched in the exposure data generation circuit 28, the read timing of the raster data corresponding to the area from which the scale pattern is extracted is adjusted.

  In the second embodiment, a pattern of the index TM is formed to indicate the reference density level. Thereby, it can be determined at a glance whether or not the detected density matches the reference density. In the exposure data generation circuit 28, raster data of the index TM is synthesized in accordance with the position of the density level preset by the operator. The raster data of the index TM is stored in the memory 32 in advance.

  FIG. 12 is a diagram showing a step tablet pattern in which the pattern length is changed.

  The mask switching pitch P affects the overall length of the step tablet pattern. By changing the mask switching pitch P, the scaling width is adjusted. FIG. 12 shows a step tablet pattern ST2 in which the scaling width is adjusted to be short from SK0 to SK1. Thereby, a step tablet pattern corresponding to a small-sized substrate can be formed.

  FIG. 13 shows a partial step tablet pattern.

  It is possible to pattern only a part of the step tablet pattern by arbitrarily setting the start and end mask patterns in a series of mask patterns. A partial density pattern is formed by performing drawing processing according to the first mask data number and the last mask data number.

  FIG. 13 shows a step tablet pattern composed of density patterns in the vicinity of 14 to 19 steps. Thereby, only a part necessary for sensitivity detection can be drawn on the substrate.

  As described above, according to the second embodiment, the step tablet pattern ST obtained by synthesizing the scale pattern P1 and the mask pattern set P2 is formed in the blank area AP of the substrate W1. While the number of steps is displayed, the density level is continuous in each area, and a stepless tablet is formed. Thereby, the substrate sensitivity can be detected with high accuracy. Note that a series of density patterns may be connected as a whole as in the first embodiment, without providing a partition between adjacent density pattern areas.

  Next, the transmission type step tablet in the third embodiment will be described with reference to FIGS. In the third embodiment, the step tablet pattern is used as a conventional sheet-like step tablet as a sensitivity detector.

  FIG. 14 is a plan view showing a step tablet according to the third embodiment. FIG. 15 is a graph showing the transmittance of the step tablet.

  The transmission-type step tablet ST4 is an elongated rectangular film generated by the above-described exposure apparatus, and a series of density patterns including a step number and a break formed in accordance with the position thereof are formed therein. Yes. As shown in FIG. 15, the transmittance changes continuously, and has the same change in transmittance as the change in the total exposure amount of the sensitivity detection pattern in the first and second embodiments.

  The step tablet ST4, which is a step chart functioning as such a sensitivity detector, can detect the sensitivity characteristics of the substrate in more detail than before. This can be used not only for a maskless exposure apparatus but also for a mask exposure apparatus.

  As a manufacturing method of step tablet ST4, it described above with respect to the base material (for example, a transparent film, glass, etc.) which apply | coated the photosensitive material which has a sensitivity characteristic that the whole series of density pattern shown in FIG. 15 was formed. Draw a step tablet pattern. And after developing, it shape | molds in the shape according to pattern size.

14 stage drive mechanism 22 DMD (light modulation element array)
30 Controller (Exposure operation controller)
SP sensitivity detection pattern

Claims (15)

A light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged;
A scanning unit that relatively moves an exposure region defined on the surface of the drawing object by the light modulation element array along a main scanning direction;
An exposure operation control unit that controls the plurality of light modulation elements according to a relative position of an exposure region, and that forms a drawing pattern on an object to be drawn by an overlap exposure operation;
An exposure apparatus characterized in that the exposure operation control section can form a pattern of a step tablet having a pattern density difference between a plurality of divided areas and in each divided area on the drawing object.   2. The exposure apparatus according to claim 1, wherein the exposure operation control unit forms a step tablet pattern in which the total exposure amount decreases or increases between adjacent divided areas and in each divided area.   The exposure operation control unit forms a step tablet pattern by increasing or decreasing the number of unused light modulation elements that are not used during exposure in the light modulation element array. The exposure apparatus according to claim 1.   The exposure operation control unit is configured by a mask pattern that defines unused light modulation elements in the light modulation element array, and a series of gradually decreasing or increasing the proportion of effective light modulation elements that are not unused. 4. The exposure apparatus according to claim 3, wherein the mask patterns are sequentially switched according to a mask switching pitch.   5. The exposure apparatus according to claim 4, wherein the exposure operation control unit can adjust a pattern length of the step tablet by changing a mask switching pitch.   6. The exposure apparatus according to claim 1, wherein the exposure operation control unit can be scaled by changing a division area division position.   The exposure apparatus according to claim 1, wherein the exposure operation control unit can form only a partial pattern of a step tablet.   The exposure apparatus according to claim 1, wherein the exposure operation control unit can form a pattern of a step tablet including an index pattern.   The exposure apparatus according to claim 1, wherein the exposure operation control unit combines a scale pattern and a series of mask patterns to form a step tablet pattern.   The exposure apparatus according to claim 1, wherein the exposure operation control unit forms a step tablet pattern in a blank area of the drawing object on which a drawing pattern is not formed.   A substrate having a step tablet pattern formed by the exposure apparatus according to claim 1.   A transmissive step tablet generated by the exposure apparatus according to claim 1. An exposure region defined on the surface of the object to be drawn by a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged, is relatively moved along the main scanning direction;
A method of controlling the plurality of light modulation elements according to a relative position of an exposure region and forming a drawing pattern on a drawing object by an overlap exposure operation;
An exposure method, wherein a pattern of a step tablet having a pattern density difference between a plurality of divided areas and within each divided area is formed on the drawing object. Exposure equipment
Exposure position detecting means for detecting an exposure position while relatively moving an exposure region defined on the surface of the object to be drawn by a light modulation element array in which a plurality of light modulation elements are two-dimensionally arranged along the main scanning direction;
A program that controls the plurality of light modulation elements according to the relative position of an exposure region and functions as an exposure operation control unit that forms a drawing pattern on an object to be drawn by an overlap exposure operation,
A program for causing a step tablet pattern having a pattern density difference between a plurality of divided areas and in each divided area to function as the exposure operation control means so as to be formed on the drawing object. A transmissive step tablet for detecting the sensitivity of a photosensitive material used in an exposure apparatus,
A scale with numerical values according to the density level,
A series of density patterns formed in a plurality of divided areas defined according to the scale,
The step tablet, wherein the series of density patterns is a pattern having a gradation in which the transmittance decreases or increases between divided areas and within each divided area.

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