Exposure apparatus, exposure method, and method of manufacturing a substrate

Abstract

The present invention provides an exposure apparatus and an exposure method. In a maskless exposure apparatus, even when a general photoresist having low sensitivity characteristics is used, a pattern can be appropriately formed. In the exposure apparatus (100), an unfinished multiple exposure operation (ME1, ME2, ME3) with the same illumination (I1), single exposure time (t), single exposure number (4 times), and pattern light is intermittently performed during three scans, and for the same portion, it is performed at the same interval.

Description

Technical Field

[0001] The present invention relates to an exposure apparatus that forms a pattern on a substrate having a photoresist layer (photosensitive material) formed on its surface using an array of light modulation elements or the like. Background Art

[0002] In a maskless exposure apparatus, while moving a stage on which a substrate is mounted along a scanning direction, pattern light is projected onto the substrate through an array of light modulation elements such as a DMD (Digital Micro-mirror Device). Here, the micro-mirrors are controlled to be turned on / off according to pattern data corresponding to the position of a projection area (hereinafter referred to as an exposure area) that moves on the substrate as the stage moves.

[0003] From the viewpoints of improving productivity, resolution, etc., a multiple exposure operation in which exposure areas during an exposure operation are overlapped is performed (for example, refer to Patent Documents 1 and 2). Among them, while the substrate is moving at a constant speed, pattern light is projected at a prescribed interval in such a manner that the minute exposure areas of the respective micro-mirrors during the exposure operation overlap each other.

[0004] During the process of passing through the exposure area, the cumulative light amount on the substrate increases and exceeds the threshold at which the properties of the film of the photosensitive material formed on the substrate change sharply, thereby forming a pattern. And, by slightly tilting the arrangement direction of the DMD with respect to the scanning direction (stage movement direction), the distribution of the center positions (exposure points) of the minute exposure areas in the exposure area is dispersed.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-36544

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2012-49433

[0007] In the case of a maskless exposure apparatus, in order to achieve an increase in productivity, the exposure amount (illuminance) in one exposure operation (single exposure) is set higher than that of a contact exposure apparatus or the like. Also, regarding the photoresist, a photoresist having a high sensitivity (low threshold) characteristic is used for the maskless exposure apparatus.

[0008] On the other hand, for reasons such as recent cost reduction requirements and replacement from a contact exposure apparatus to a maskless exposure apparatus, a general-purpose photoresist having a low sensitivity is also used in the maskless exposure apparatus. In this case, the characteristics of maskless exposure such as high illuminance and short exposure time do not match the reaction speed of the general-purpose photoresist having a low sensitivity characteristic with long exposure at low illuminance as a premise, and thus exposure defects such as poor shape of the cross-sectional profile, poor gloss of the surface portion of the photoresist, or insufficient curing are likely to occur. Summary of the Invention

[0009] Therefore, in a maskless exposure apparatus, it is desired to appropriately form a pattern even when a general photoresist having low sensitivity characteristics is used.

[0010] The exposure apparatus of the present invention includes: an optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements; a scanning unit that relatively moves an exposure region of the optical modulation element array with respect to an object to be exposed having a photoresist layer formed on a surface thereof in a main scanning direction; and an exposure control unit that controls the optical modulation element array and the scanning unit to perform multiple exposures on the object to be exposed at a predetermined exposure interval in the main scanning direction, and the exposure control unit performs multiple exposures (hereinafter referred to as unfinished multiple exposures) in which the cumulative exposure amount in one scan does not exceed the exposure sensitivity (threshold value) of the photoresist at a predetermined time interval.

[0011] The exposure interval of the multiple exposure operation in one scan, the illuminance (light intensity) during single exposure, the number of multiple exposures, the pattern, etc. are arbitrary. For example, the exposure control unit adjusts the exposure time or scanning speed of one unfinished multiple exposure to perform only the number of unfinished multiple exposures exceeding the exposure sensitivity of the photoresist on a predetermined object to be exposed portion. Alternatively, the exposure control unit adjusts the illuminance during one exposure of the unfinished multiple exposure to perform only the number of unfinished multiple exposures exceeding the exposure sensitivity of the photoresist on a predetermined object to be exposed portion.

[0012] The exposure control unit can perform unfinished multiple exposures on a predetermined object to be exposed portion multiple times with the same pattern. And, it is possible to perform unfinished multiple exposures on a predetermined object to be exposed portion multiple times by scanning in the same direction. The exposure control unit can control the optical modulation element array to modulate a plurality of optical modulation elements in accordance with the same operation control sequence to perform unfinished multiple exposures for each scan on a predetermined object to be exposed portion.

[0013] In the case of having a plurality of optical modulation element arrays, the scanning unit can perform reciprocating scanning in which the exposure regions of the respective optical modulation element arrays pass through different scanning bands in the forward and return paths. Multiple exposure operations can be performed on the same object to be exposed portion multiple times at the same time interval in the scanning bands of the respective optical modulation element arrays.

[0014] The exposure apparatus of the present invention includes: an optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements; a scanning unit that relatively moves the exposure area of the optical modulation element array with respect to an exposure object having a photoresist layer formed on its surface along the main scanning direction; and an exposure control unit that controls the optical modulation element array and the scanning unit to perform multiple exposures on the exposure object at a predetermined exposure interval in the main scanning direction. The exposure control unit performs multiple exposures on a predetermined exposure target portion by scanning multiple times. For example, the multiple exposure operation based on multiple scans can be performed in such a manner that a threshold value exceeding or greater than the threshold value corresponding to the above exposure sensitivity is achieved.

[0015] In an exposure method according to one aspect of the present invention, the exposure area of an optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements is relatively moved with respect to an exposure object having a photoresist layer formed on its surface along the main scanning direction, and the optical modulation element array and the scanning unit are controlled to perform multiple exposures on the exposure object at a predetermined exposure interval in the main scanning direction. Herein, multiple exposures based on one scan are repeatedly performed on a predetermined exposure target portion at a predetermined time interval. For example, multiple incomplete multiple exposures are performed at a predetermined time interval, where the incomplete multiple exposure means that the cumulative exposure amount in one scan does not exceed the exposure sensitivity of the photoresist.

[0016] In a substrate of the present invention formed by the above exposure method, a stripe pattern is formed in the cross section of the photoresist layer in the direction along the surface. For example, the required exposure energy corresponding to the exposure sensitivity of the photoresist is 300 mJ / cm 2 The above substrate is applied with the above exposure method to form a pattern on the substrate.

[0017] According to the present invention, in a maskless exposure apparatus, even when a general photoresist with low sensitivity characteristics is used, a pattern can be appropriately formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a block diagram of the exposure apparatus according to the first embodiment.

[0019] Figure 2 is a diagram showing a timing chart of the multiple exposure operation.

[0020] Figure 3 is a diagram showing the scanning paths of a plurality of exposure heads.

[0021] Figure 4 is a diagram schematically showing a cross section near a via portion after development.

[0022] Figure 5 is a diagram showing the flow of the multiple exposure operation.

[0023] Figure 6 This is a diagram showing the timing chart of the multiple exposure operation of the second embodiment.

[0024] Reference Numeral Explanation

[0025] 10: Exposure head; 19: Stage drive mechanism (scanning unit); 22: DMD (optical modulation element array); 30: Controller (exposure control unit, scanning unit); 100: Exposure apparatus. Detailed Embodiment

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0027] Figure 1 This is a block diagram of the exposure apparatus of the first embodiment.

[0028] The exposure apparatus 100 is a maskless (direct) exposure apparatus that forms a pattern on a substrate W on which a layer of a photosensitive material such as a photoresist is formed on the surface, for example, a negative photoresist such as solder mask ink is applied. The exposure apparatus 100 includes: a light source unit 20 composed of a plurality of discharge lamps (not shown here); and a plurality of exposure heads 10 that project pattern light onto the substrate W, respectively. In addition, only the light source unit 20 and the exposure head 10 of one system are shown here.

[0029] The exposure head 10 includes an illumination optical system 21, a DMD 22, and an imaging optical system 23, and the illumination optical system 21 is provided with an optical filter 25 that reduces the intensity of ultraviolet light in a specific wavelength region. The light source unit 20 is composed of a discharge lamp (not shown) that emits ultraviolet light, etc., and is driven by a light source drive unit 42.

[0030] When CAD / CAM data composed of vector data or the like is input to the exposure apparatus 100, the vector data is converted into raster data in a raster conversion circuit 26. The generated raster data is temporarily stored in a buffer memory (not shown) and then sent to a DMD drive circuit 24.

[0031] The DMD 22 is an optical modulation element array obtained by two-dimensionally arranging minute micromirrors, and each micromirror can selectively switch the reflection direction of light by changing its posture. The DMD drive circuit 24 outputs exposure data for performing on / off control of each micromirror, whereby light corresponding to the pattern is projected (imaged) onto the surface of the substrate W via the imaging optical system 23.

[0032] The controller (exposure control unit) 30 controls the light source drive unit 42, the filter drive unit 44, the DMD drive circuit 24, the stage drive mechanism 29, etc. to perform an exposure operation. Further, the controller 30 reads out information related to exposure from the memory 32. The stage drive mechanism 29 relatively moves the exposure stage 18 on which the substrate W is mounted with respect to the exposure head 10 according to a control signal from the controller 30. The position detection unit 27 calculates the exposure position on the surface of the substrate W based on a signal sent from the stage drive mechanism 19. In addition, the direction along the movement path of the exposure stage 18 is defined as the main scanning direction X, and the direction perpendicular to the direction along this movement path is defined as the sub-scanning direction Y.

[0033] During exposure, the exposure stage 18 moves at a constant speed along the main scanning direction X. The exposure area, which is the projection area of the entire DMD 22, relatively moves along the main scanning direction X on the substrate W as the substrate W moves. In addition, the moving direction of the substrate W is slightly inclined with respect to the arrangement direction of the DMD, that is, the end edge along the main scanning direction X of the exposure area. Alternatively, it may not be slightly inclined with respect to the main scanning direction X.

[0034] The controller 30 controls each micromirror of the DMD 22 according to the relative position of the exposure area to perform a multiple exposure operation. That is, the exposure operation is performed at a prescribed exposure interval, and the distribution of the center positions (exposure points) of the minute exposure areas of each micromirror is dispersed substantially uniformly, and the pattern light is projected overlappingly. The multiple exposure operation is performed on the entire substrate W by a plurality of exposure heads including the exposure head 10, whereby a pattern is formed on the entire substrate W.

[0035] In the present embodiment, a multiple exposure operation is performed in which the cumulative exposure amount does not exceed the threshold value of the photosensitive material during one scan, that is, during the period when the exposure area passes through the exposure target portion. And this multiple exposure operation is repeated in multiple scans. Hereinafter, this will be described in detail.

[0036] Figure 2 FIG. is a timing chart showing the multiple exposure operation. Figure 3 FIG. is a diagram showing the scanning paths of a plurality of exposure heads. However, in Figure 3 for ease of explanation, the movement paths of the exposure areas of two exposure heads are shown. In addition, the exposure area is not slightly inclined with respect to the main scanning direction X.

[0037] Figure 2 The multiple exposure operation ME1 shown represents the timing of a multiple exposure operation in which four exposure operations are continuously performed at a prescribed exposure interval during the period of passing through the Figure 3 shown exposure target portions SA1, SA2. Here, the exposure target portions SA1, SA2 are arbitrary exposure target portions.

[0038] The irradiation period of the single exposure (single shot exposure), i.e., the period during which the micro mirror switches from off to on and scans the light (the period during which scanning is performed in a state where light is irradiated onto the exposure surface) \(t\), and the illuminance \(I_1\) are determined such that the cumulative exposure amount in one scan does not exceed the exposure sensitivity of the photoresist, i.e., the exposure amount required for pattern formation (hereinafter, also referred to as the threshold). Hereinafter, the insufficient multiple exposure in which the photosensitivity required for pattern formation of the photoresist is not achieved by one scan along the main scanning direction \(X\) is referred to as "incomplete multiple exposure".

[0039] As Figure 3 shown, the exposure regions \(EA1\) and \(EA2\) reciprocally move on the adjacent scan bands \(SB1\), \(SB2\) and scan bands \(SB3\), \(SB4\) with respect to the substrate \(W\), respectively. When the movement of the exposure regions \(EA1\) and \(EA2\) on the scan bands \(SB1\) and \(SB3\) ends, the stage drive unit 29 moves the exposure stage 18 in the sub-scanning direction \(Y\), and causes the exposure regions \(EA1\) and \(EA2\) to move along the scan bands \(SB2\) and \(SB4\) in the direction opposite to the forward path, respectively. When the exposure regions \(EA1\) and \(EA2\) reciprocally move, the stage drive unit 29 causes the exposure regions \(EA1\) and \(EA2\) to move along the scan bands \(SB1\) and \(SB3\) again.

[0040] When the exposure regions \(EA1\) and \(EA2\) pass through the exposure target portions \(SA1\) and \(SA2\) of the scan bands \(SB1\) and \(SB3\) again, the second incomplete multiple exposure operation \(ME2\) is executed (refer to Figure 2 ). The single exposure time, illuminance, and number of single exposures at this time are the same as those of the first incomplete multiple exposure operation \(ME1\), and further, the time interval corresponding to the exposure interval until the next single exposure is executed, the pattern light (pattern data), and the operation sequence (on / off control sequence) of the micro mirror of the DMD are also the same.

[0041] Then, the exposure region \(EA1\) reciprocally moves (orbital movement) on the scan bands \(SB1\) and \(SB2\), while the exposure region \(EA2\) reciprocally moves (orbital movement) on the scan bands \(SB3\) and \(SB4\). When passing through the exposure target positions \(SA1\) and \(SA2\) respectively in the third scan, the third incomplete multiple exposure operation \(ME3\) is executed.

[0042] When a total of three incomplete multiple exposure operations \(ME1\), \(ME2\), and \(ME3\) are executed, the cumulative light amount of the exposure target portions \(SA1\) and \(SB2\) exceeds the threshold of the photoresist. As a result, a pattern is formed on the photoresist. Since the photoresist is negative, the ultraviolet irradiated portion is cured.

[0043] The illuminance I1, the single exposure time t, and the number of single exposures (here, 4 times) are determined in such a way that the cumulative light amount exceeds the threshold of the photoresist by not completing the multiple exposure operations ME1, ME2, and ME3. The photoresist used in this embodiment is a so-called general photoresist having a sensitivity characteristic premised on a contact exposure apparatus, a proximity exposure apparatus, etc., and the exposure energy (cumulative light amount) required for pattern formation is 300 mJ / cm 2 ~600 mJ / cm 2 . This photoresist has a lower sensitivity (higher threshold) compared to a high-sensitivity photoresist used for a maskless exposure apparatus.

[0044] In Figure 2 , the continuous irradiation operation CE0 of the cumulative light amount required to exceed the threshold of the photoresist in the case of using a contact exposure apparatus or a proximity exposure apparatus, etc. is shown by a dashed line. The cumulative light amount of the three times of uncompleted multiple exposure operations ME1, ME2, and ME3 is approximately equal to the cumulative light amount of the continuous irradiation operation CE0 shown by the dashed line. The time for photosensitive completion reaching the light amount based on the continuous irradiation operation CE0 by continuous exposure in a contact exposure apparatus or a proximity exposure apparatus is about several seconds.

[0045] In Figure 2 , the multiple exposure operation ME0 that exceeds the threshold of the photoresist in one scan in the exposure apparatus 100 is also shown accordingly. The illuminance I1 of the uncompleted multiple exposure operation is the same as the illuminance of the multiple exposure operation ME0, but the single exposure time t of the uncompleted multiple exposure operation is shorter than the single exposure time t0 of the multiple exposure operation ME0. In addition, as a structure for shortening the single exposure time t, the micromirror opening time can be adjusted, or the scanning speed can be increased to shorten the single exposure time t.

[0046] The scanning speeds of the exposure regions EA1 and EA2 are both constant in the forward path, and the movement of the exposure stage 18 along the sub-scanning direction Y also moves at a constant speed. Therefore, the interval T1 from the first uncompleted multiple exposure operation ME1 to the second uncompleted multiple exposure operation ME2 is equal to the interval T2 from the second uncompleted multiple exposure operation ME1 to the third uncompleted multiple exposure operation ME2. The intervals T1 and T2 (several seconds to several tens of seconds) are longer than the single exposure time t (several milliseconds) and the time interval PT corresponding to the exposure interval (several milliseconds).

[0047] Since the exposure target areas SA1 and SA2 are set to arbitrary areas of the substrate W, the exposure target areas of any of the scanning bands SB1, SB2 and scanning bands SB3, SB4 have the same single exposure time t, illuminance I1, number of single exposures (4 times), and time interval PT corresponding to the exposure interval. The unfinished multiple exposure actions based on the same pattern and the same DMD operation (the same mirror operation sequence) are performed 3 times at the same interval. By repeatedly performing such the same unfinished multiple exposure actions for the same area based on multiple scans, a good pattern can be formed.

[0048] Figure 4 It is a diagram schematically showing a cross section near the via hole portion after development.

[0049] The via hole portions VP1 and VP2 are parts that are not irradiated with ultraviolet rays and are dissolved and removed during development. The photoresist FR around the via hole portion VP is irradiated with ultraviolet rays and does not melt but solidifies. Figure 4 The via hole portion VP1 shown in (A) of Figure 2 is a via hole portion formed by the multiple exposure action ME0 of Figure 4 The via hole portion VP2 shown in (B) of

[0050] As shown in Figure 4 (A), when the via hole portion VP1 is formed by one multiple exposure action, due to reasons such as the diffusion of the photopolymerization reaction range with increasing depth, the via hole wall surface is formed into a conical shape. And, since the photoresist FR having a low sensitivity characteristic is subjected to a single exposure with a relatively high illuminance I1, there are problems such as gloss and color development defects due to insufficient surface curing, and cracks are generated due to excessive exposure of only the surface portion.

[0051] On the other hand, as shown in Figure 4 (B), for the via hole portion VP2 formed by the unfinished multiple exposure actions ME1 to ME3, the photopolymerization reaction occurs multiple times (3 times) stage by stage, and the diffusion of the photopolymerization reaction based on one unfinished multiple exposure action is suppressed. As a result, the via hole wall surface becomes a vertical wall surface instead of a conical shape. In addition, since the single exposure time is short, the cumulative light amount of one unfinished multiple exposure action is suppressed, so there are no problems such as the appearance of the resist surface or the pattern shape.

[0052] In addition, as a history of the photopolymerization reaction occurring stage by stage, a stripe pattern M is formed along the lateral direction (surface direction) in the photoresist cross section. In order to uniformly generate such a stripe pattern M on the entire substrate, a cyclic reciprocating scanning method is adopted to make the time interval for performing the unfinished multiple exposure action constant.

[0053] Figure 5 It is a diagram showing the process of the multiple exposure operation.

[0054] The exposure device 100 loads exposure setting information such as exposure data and CAD / CAM data into the controller 30 together. Then, the transfer device (not shown in Figure 1 ) places the substrate on the exposure table 18 (S101, S102). After adjusting the illuminance, the exposure device 100 measures the position of the alignment marks, and measures the position and deformation of the substrate W (S103, S104). Then, the controller 30 corrects the exposure data based on the alignment mark information (S105), performs multiple scans by driving control of the table drive mechanism 29, and repeats the unfinished multiple exposure operation by controlling the DMD drive circuit 24 (S106). When the drawing of the entire substrate W is completed, the next substrate is replaced (S107).

[0055] Thus, according to the present embodiment, in the exposure device 100, the unfinished multiple exposure operations ME1, ME2, and ME3 with the same illuminance I1, single exposure time t, single number of times (4 times), and pattern light are intermittently performed during three scans, and for the same part, they are performed at the same interval.

[0056] By performing the multiple exposure operation corresponding to the low-sensitivity photoresist assuming a contact exposure device, a pattern can be well formed even for a low-sensitivity photoresist. In addition, by increasing the scan speed and performing multiple scans, even if the same part is exposed multiple times, a reduction in production capacity can be suppressed.

[0057] Instead of the structure in which the exposure area reciprocates along adjacent scan bands, the exposure area can reciprocally scan on the same scan band. In this case, no exposure operation is performed in the loop, and thus the unfinished multiple exposure operation based on the same interval can be performed.

[0058] The single exposure time, number of exposure times, illuminance, number of unfinished multiple exposure operations, etc. can be appropriately determined according to the sensitivity characteristics of the photoresist, etc. In addition, a positive photoresist can also be applied.

[0059] Next, Figure 6 The second embodiment will be described. In the second embodiment, the illuminance during single exposure is suppressed.

[0060] Figure 6 It is a diagram showing the timing chart of the multiple exposure operation of the second embodiment.

[0061] The number of single exposures for each of the incomplete multiple exposure operations ME1' to ME3' is the same as that in the first embodiment (4 times), but the exposure is performed at an illuminance I2 lower than the illuminance I1 in the first embodiment. The illuminance I2 corresponds to the illuminance set in contact exposure apparatuses, proximity exposure apparatuses, etc. On the other hand, the single exposure time t' is longer than the single exposure time in the first embodiment. The intervals T1' and T2' for performing the incomplete multiple exposure operations ME1' to ME3' are equal. By suppressing the illuminance during one exposure in this way, it is also possible to cause a stepwise photopolymerization reaction in the photoresist.

[0062] In the first and second embodiments, the number of incomplete multiple exposure operations is determined such that the cumulative exposure amount exceeds the exposure sensitivity of the photoresist, that is, the exposure amount required for pattern development. However, in the case of a negative photoresist, there are times when a multiple exposure operation that not only exceeds the exposure sensitivity but also provides a cumulative exposure amount required for sufficient curing of the resist is desired. In this case, the number of incomplete multiple exposure operations can be set to a larger number according to the value exceeding the threshold. Moreover, even when the exposure sensitivity is exceeded by one multiple exposure operation, sufficient curing of the resist can be achieved by configuring to repeat the multiple exposure operation by scanning the same portion multiple times.

Claims

1. An exposure device, characterized in that: The exposure device has: An optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements; A scanning unit that relatively moves the exposure area of the optical modulation element array relative to an exposure object having a photoresist layer formed on its surface along the main scanning direction at a constant speed; And An exposure control unit that controls the optical modulation element array and the scanning unit to perform multiple exposures on the exposure object at a prescribed exposure interval in such a manner that the minute exposure areas of the respective optical modulation elements overlap each other, The exposure control unit performs an incomplete multiple exposure a plurality of times at prescribed time intervals, where the incomplete multiple exposure means that the cumulative exposure amount in one scan does not exceed the exposure sensitivity of the photoresist in the photoresist layer.

2. The exposure device according to claim 1, characterized in that: The exposure control unit performs an incomplete multiple exposure on a prescribed exposure target part a plurality of times with the same pattern.

3. The exposure device according to claim 2, characterized in that: The exposure control unit performs an incomplete multiple exposure on a prescribed exposure target part a plurality of times by scanning in the same direction.

4. The exposure device according to claim 3, characterized in that: The exposure control unit controls the optical modulation element array to modulate a plurality of optical modulation elements in accordance with the same operation control sequence, and performs an incomplete multiple exposure for each scan on a prescribed exposure target part.

5. The exposure device according to claim 1, characterized in that: The exposure device has a plurality of optical modulation element arrays, The scanning unit performs a reciprocating scan in which the exposure areas of the respective optical modulation element arrays pass through different scanning bands in the forward and return paths.

6. The exposure device according to any one of claims 1 to 5, characterized in that: The exposure control unit adjusts the exposure time or scanning speed of one incomplete multiple exposure to perform an incomplete multiple exposure on a prescribed exposure target part only for a number of times exceeding the exposure sensitivity of the photoresist.

7. The exposure device according to any one of claims 1 to 5, characterized in that: The exposure control unit adjusts the illuminance during one exposure of the incomplete multiple exposure to perform an incomplete multiple exposure on a prescribed exposure target part only for a number of times exceeding the exposure sensitivity of the photoresist.

8. An exposure device, characterized in that: The exposure device has: An optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements; A scanning unit that relatively moves the exposure area of the optical modulation element array relative to an exposure object having a photoresist layer formed on its surface along the main scanning direction at a constant speed; And An exposure control unit that controls the optical modulation element array and the scanning unit to perform multiple exposures on the exposure object at a prescribed exposure interval in such a manner that the minute exposure areas of the respective optical modulation elements overlap each other, The exposure control unit performs multiple exposures on a prescribed exposure target part a plurality of times through multiple scans.

9. An exposure method The exposure area of an optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements is relatively moved at a constant speed along the main scanning direction with respect to an exposure object having a photoresist layer formed on its surface by means of a scanning unit. The optical modulation element array and the scanning unit are controlled to perform multiple exposures on the exposure object at a prescribed exposure interval in such a manner that the minute exposure areas of the respective optical modulation elements overlap each other. It is characterized in that Multiple exposures based on one scan are repeatedly performed on a prescribed exposure target part at a prescribed time interval.

10. An exposure method The exposure area of an optical modulation element array obtained by two-dimensionally arranging a plurality of optical modulation elements is relatively moved at a constant speed along the main scanning direction with respect to an exposure object having a photoresist layer formed on its surface by means of a scanning unit. The optical modulation element array and the scanning unit are controlled to perform multiple exposures on the exposure object at a prescribed exposure interval in such a manner that the minute exposure areas of the respective optical modulation elements overlap each other. It is characterized in that Incomplete multiple exposures are performed multiple times at prescribed time intervals. The incomplete multiple exposure means that the cumulative exposure amount in one scan does not exceed the exposure sensitivity of the photoresist in the photoresist layer.

11. A method for manufacturing a substrate, which forms a pattern on a photoresist layer on the surface by the exposure method according to claim 9 or 10, characterized in that The photoresist layer is formed with a stripe pattern in a direction along the surface in its cross section.

12. The method for manufacturing a substrate according to claim 11, characterized in that The required exposure energy corresponding to the exposure sensitivity of the photoresist in the photoresist layer is 300 mJ / cm 2 or more.

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