KR102643140B1 - Method of exposure using disital image - Google Patents

Abstract

In the maskless digital photolithography process, when performing a split exposure method in which the overall image is divided into regions and each divided image is sequentially transferred to the substrate, the boundary line of the pattern area is the area where light is irradiated within each divided image. In the middle, at least in the section connected to the pattern area of the adjacent split image, a range is set to have a certain width each inside and outside around the boundary line, and within that range, the amount of light or optical dose is reduced from the inside to the outside. An exposure method is disclosed, which includes the steps of forming a processed segmented image and exposing the corresponding segmented area on a substrate using the processed segmented image.
According to the present invention, even if an expensive, high-precision moving stage is not adopted, it is possible to maintain a relatively accurate light dose level in the pattern area through exposure method during split exposure or change in exposure amount given by position at the border of the pattern, and exposure equipment. Even when the setting conditions for movement of the stage change somewhat, the occurrence of double exposure and unexposed areas in the pattern area can be suppressed.

Description

Digital image exposure method {METHOD OF EXPOSURE USING DISITAL IMAGE}

The present invention relates to a digital image exposure method, and more specifically, to a digital image exposure method, which generates a digital image (monochromatic wavelength laser, LED light source, etc.) by reflecting or transmitting it to a computer-controlled micro mirror or LCD device without using an exposure mask. It relates to a digital image exposure method in digital photolithography technology that irradiates and develops an image onto a photosensitive layer.

In general, fine patterns are produced on a substrate through a photolithography process, which can be performed in one process step in a semiconductor process or flat display manufacturing process. Usually, in order to form a fine pattern, an exposure mask is produced by drawing the fine pattern to be implemented on a transparent substrate such as glass or quartz using a metal layer, which is a non-transmissive layer. The manufactured exposure mask is placed on the photoresist, which is a photosensitive material coated on the substrate on which the fine pattern is to be processed, and light is shined on it so that the light reaches the photosensitive material through the exposure mask, so that the fine pattern of the exposure mask is formed on the photosensitive material layer. to be transcribed. Depending on its characteristics, the photosensitive material that receives light becomes a material that is easily soluble in a developer or a material that is difficult to dissolve in a developer, and when developed in this state with a developer, a fine pattern consisting of a photoresist layer remains. When this fine pattern is etched on the substrate using an etch mask, a fine pattern is formed on the substrate.

In this type of photolithography process using an exposure mask, if the fine pattern to be obtained through the process changes, a new exposure mask must be manufactured. To solve the problem of the inconvenience of making an exposure mask like this every time, a separate exposure mask has recently been developed. A method was developed to form an etch mask without an exposure mask by directly projecting a digital image generated by a computer onto the photosensitive material layer, and using this to perform etching and obtain a fine pattern on the substrate, which is called maskless digital photolithography. It is called Digital Photolighography.

However, when performing exposure work to create an etch mask using a maskless digital photolithography technique, in order to increase spatial resolution, the digital image is reduced using a lens system similar to a microscope, and the image is projected onto the photosensitive material layer on the substrate surface. It is common to do so. As a result, the size of the area on the substrate that can be exposed at once is generally 1mm x 1mm or less in most cases.

Therefore, as shown in Figure 1, if the size of the overall pattern a to be acquired is larger than b, which is the effective focus image area of the projection lens, the divided images obtained by dividing the entire image into several parts as shown in Figure 1 are divided into corresponding areas on the substrate ( By sequentially projecting to the divided areas, the entire image is projected onto the substrate, thereby performing split exposure so that a pattern according to the entire image is implemented on the photosensitive material layer on the substrate.

For sequential projection of split images, for example, as in a typical stepper device, the digital image projector including the light source and the surrounding lens system are fixed and the substrate (wafer) on which the image reaches is adjusted to the exposure grid interval as shown in Figure 2. After accurately moving horizontally or vertically by an amount or the size of the effective exposure area (segment area: a), a new area next to the already exposed area must be exposed to obtain the entire pattern (b) on the substrate. However, at this time, if the stage that moves the wafer (substrate) does not move exactly by the grid spacing and moves excessively or moves insufficiently, a gap occurs between the divided images or the division occurs in the entire projected image as shown in Figure 3 or 4. Overlapping areas may be formed between images, and as a result, a gap (c) may occur or an overlapping area (d) may be formed in the entire pattern formed.

In this case, the amount of light or light dose detected in the pattern area of the substrate can be expressed as shown in Figures 5 and 6. In FIGS. 5 and 6, the horizontal axis represents the position on a straight line that cuts the entire pattern horizontally in the entire image obtained by integrating the individual segmented images of FIGS. 3 and 4, and the vertical axis represents the light dose size at each position on the straight line. .

When split exposure is performed and a split image exposure is made for the split area at a precise location, if the optical doze level of the pattern area is expressed as a line, the optical doze level is displayed as one continuous horizontal line over the entire pattern area. can be maintained at a uniform level. However, in Figures 5 and 6 corresponding to the cases of Figures 3 and 4, the line representing the light dose level rapidly decreases in the unexposed interval part (b), and the light dose becomes 0 or the overlapped area (c) ), you can see that the light dose increases rapidly due to overlapping exposure, doubling the value. As a result, a problem may occur in which the correct image is not projected on the substrate, and a proper etch mask pattern cannot be formed in the photosensitive material layer on the substrate.

To prevent these problems, the movement precision of the stage on which the substrate is placed must be very high. Therefore, an expensive exposure equipment stage is needed that can determine the position of the stage in real time and precisely control the position through feedback, resulting in an increase in the unit cost of the equipment.

Republic of Korea Patent Publication No. 10-2001-0095798: Stepper exposure method Republic of Korea Patent Publication No. 10-2009-0076457: Maskless exposure system using DMD

https://www.artwork.com/raster/dmd/players.htm

In the conventional maskless digital photolithography process described above, the present invention addresses the problem of overlap or separation between the divided images constituting the entire image on the substrate during divided exposure without adopting an expensive stage in the exposure equipment. Accordingly, the purpose is to provide an exposure method that can reduce or solve the problem of not forming an etch mask of a normal shape due to separation (gap) or overlap (overlap) in the pattern area within the entire image formed on the substrate.

The exposure method of the present invention for achieving the above object is a divided exposure method in which each divided image obtained by dividing the overall image into regions in a maskless digital photolithography process is sequentially transferred to the substrate for each divided region.

Among the borderlines of the pattern area, which is the area where light is irradiated within each split image, a range is set to have a certain width each inside and outside around the borderline, at least in the section connected to the pattern area of the adjacent split image, and the inner and outer edges are set within that range. Characterized by a process of forming a processed divided image with a reduced amount of light or optical dose going outward, and using this processed divided image to expose the corresponding divided area on the substrate. do.

At this time, the processed divided image is expanded by a certain width outside of the pattern boundary of the divided image in the section, so that the processed divided image can be projected onto a substrate with an area slightly larger than the corresponding divided area of the divided image. there is.

In this case, assuming that the processed segmented image is transferred or projected at an exact location on the substrate, the pattern area of one processed segmented image is expanded by a certain width outside of the pattern boundary of the segmented image in the section, The processed segmented images are projected onto the substrate so that they overlap the pattern areas of other processed segmented images located adjacent to each other within a certain inner and outer width range.

In addition, when the size of the divided image is expanded as described above, there is a difference in the area to be exposed, so projecting the processed divided image onto the divided area of the substrate on which the conventional divided image is projected requires that the center of the conventional divided image be It can be thought of as a projection that allows the center of the processed divided image to be located at the center of the corresponding divided area of the substrate.

In the method of the present invention, the light dose at the boundary portion corresponding to a certain width range inside and outside the pattern boundary of the processed divided image may be gradually reduced from the light dose level for the original pattern area to 0.

In the method of the present invention, a certain width is calculated in the direction perpendicular to the boundary line of the pattern area, and the exposure area of a certain width to form a boundary is not expanded to the outside at the edge of the pattern area, thereby preventing exposure by light irradiation. .

In the present invention, the processed segmented image is calculated from the segmented image through a computer image processing operation, and the initial light beam is projected by a primary digital image projector including a light source, which is then projected to a digital micromirror device (DMD). ) can be obtained by implementing an image containing a pattern with a border using DLP (digital light processing), and the adjustment or manipulation of the DMD for implementing such an image is done through computer image processing that takes into account the pattern in the entire image. This can be achieved by obtaining a processed segmented image, converting it into data, and transmitting it to the DMD. Therefore, in a broad sense, it can be said that both the segmented image and the processed segmented image are obtained through computer image processing.

In the present invention, the operation of forming a processed split image by adjusting (reducing) the light dose at a certain width inside and outside around the border of the pattern area of the split image is performed in all border sections of the pattern area of the split image, and the light dose is , it may be determined that the photosensitive material layer is effectively exposed to the area exposed at a light dose level that is more than half of the light dose level for the pattern area before processing, and the exposure is performed in an amount that forms an etch mask.

In addition, in the present invention, the area where the light dose is adjusted (reduced) at a certain width inside and outside around the boundary line includes the above section of the boundary line, but is not necessarily limited to the above section, and the entire image is reproduced close to the original on the substrate. In order to achieve this, the section may be added or subtracted around the section as needed, and the light dose may be reduced by a certain amount for all pattern boundaries to easily obtain a processed segmented image.

According to the present invention, in a device that performs photolithography by projecting a digital image onto a substrate, when the size of the image to be exposed is larger than the image area that can be exposed at once, it must be exposed by dividing it into several areas. That is, when performing split exposure, there is a problem in which the boundaries of adjacent divided areas are not exposed or double exposed due to inaccurate relative movement of the stage with respect to the part that projects the image (e.g., digital image projector and lens system). This effectively solves the problem of inaccurate images obtained on the substrate due to inaccurate movement, allowing accurate patterns to be exposed on the substrate during split exposure.

According to the present invention, when split exposure is performed to project an image larger than the image area that can be projected at once on a substrate, the split image is not accurately transferred to the divided area on the substrate, and errors occur within a certain range, causing overlap or separation. Even in this case, it is possible to ensure that the light dose in the pattern area does not deviate significantly from the normal level.

Therefore, according to the present invention, even if an expensive, high-precision moving stage is not adopted, it is possible to maintain a relatively accurate light dose level in the pattern area through the exposure method during split exposure or by changing the exposure amount given for each position at the border of the pattern. Even when the setting conditions for stage movement in the equipment change slightly, the occurrence of double exposure and unexposed areas in the pattern area can be suppressed.

Figure 1 is an illustration to explain the concept of split exposure by dividing the entire image into split images divided by a plurality of grids (indicated by dotted lines) when the size of the entire image a to be exposed is larger than the maximum projection area b that can be exposed. do,
Figure 2 is an explanatory diagram showing a case in which sequential exposure is performed on divided areas of the substrate as a divided image, and exposure is performed at a fixed position;
Figure 3 is an explanatory diagram showing a case where divided exposure is sequentially performed on divided areas of the substrate with divided images, and a gap (gap) between divided images occurs due to an error in the moving distance of the substrate stage;
FIG. 4 is an explanatory diagram showing a case where divided exposure is sequentially performed on a divided area of the substrate with a divided image, and an overlap or double exposure portion occurs between the divided images due to an error in the moving distance of the substrate stage;
Figure 5 shows the change in light dose level by position of the pattern area of each split image and the split image when a gap occurs between the pattern areas of each split image when the entire image is reconstructed on the substrate by split exposure as shown in Figure 3. A graph showing the change in light dose level by location for the entire pattern area combined with the pattern areas,
Figure 6 shows the change in light dose level for each position of the pattern area of each split image and the split image when overlap occurs between the pattern areas of each split image when the entire image is reconstructed on the substrate by split exposure as shown in Figure 4. A graph showing the change in light dose level by location for the entire pattern area combined with the pattern areas,
Figure 7 is a conceptual explanatory diagram for explaining the invention concept, which has an upper plan view portion and a lower perspective view portion;
Figure 8 is a plan view conceptually showing a state in which a divided image processed by an embodiment of the method of the present invention is obtained and sequential exposure is performed while moving the substrate from left to right on the stage while using the processed divided images;
Figure 9 shows the change in light dose level (d) for each pattern area position of each processed divided image and the total when a processed divided image is obtained and exposed to the processed divided image according to an embodiment of the method of the present invention. A graph showing the change in light dose level (e) for each position in the pattern area, showing a case where exposure is performed at an accurate position,
FIG. 10 is the same as FIG. 9 in other respects, but is a graph showing a case where the processed divided image is projected to a location deviating from the original position of the substrate divided area and exposure occurs while separation as in FIG. 3 occurs.
FIG. 11 is the same as FIG. 9 in other respects, but is a graph showing a case where the processed divided image is projected to a location deviating from the original position of the divided area of the substrate and exposure occurs while overlapping as shown in FIG. 4.

Hereinafter, the present invention will be described in more detail through specific examples with reference to the drawings.

Figure 7 is a conceptual explanatory diagram to better explain the invention concept mentioned above and has an upper plan view portion and a lower perspective view portion. Here, the concept of performing exposure is shown by sequentially projecting two adjacent processed divided images onto the divided area of the substrate. Here, the first exposed split image gradually increases the amount of light or optical dose from the inside to the outside over a certain range in the section connected to the pattern area of the adjacent split image (secondary exposed split image) at the center of the border of the pattern area. The image is processed to reduce and reach 0 at the outermost point to form a processed split image, and the second exposed split image is similarly processed to form a processed split image, and the first exposed image is exposed to a certain range above. It shows that the processed segmented image and the processed segmented image subjected to secondary exposure are exposed to overlap.

At this time, the top plan view shows that the light dose of the pattern area has no difference from the light dose of other pattern areas in the overlapped area within a certain range, and the bottom perspective view shows that the pattern boundary of each processed segmented image is inside the certain range. It shows that the light dose gradually decreases from to the outside.

Figure 8 is a plan view conceptually showing a state in which a segmented image processed by an embodiment of the method of the present invention is obtained and exposure is performed on the processed segmented image.

9 to 11 show the respective processed images in the case where, during split exposure, a split image processed according to an embodiment of the method of the present invention is obtained, exposure is performed with this processed split image, and the entire image is reconstructed on the substrate. This is a graph showing the change in light dose level by position in the pattern area of the split image and the change in light dose level by position in the entire pattern area obtained by overlapping the patterns of each processed split image.

In particular, Figure 9 shows a case where each processed divided image is projected or projected to an exact position on the corresponding divided area of the substrate and exposed, and the light dose level for each position is changed along the line AA of Figure 8. It represents.

In this embodiment of the divided exposure, the entire image containing the desired pattern is divided into regions in a maskless digital photolithography process to obtain a divided image, and each divided image thus obtained is sequentially placed on the substrate for each divided region corresponding to each divided image. This is done to implement an overall image containing a desired pattern on the photosensitive material layer on the substrate, that is, to obtain an etching mask (depending on the semiconductor process, it may be an ion implantation mask or a deposition mask, etc.) with the desired pattern.

In conventional split exposure, the pattern area in the split image is the area where exposure takes place, the area where light is irradiated, and the light quantity or light dose is large, and the remaining area is the area where no exposure is made due to no or weak light, and this division is a dichotomy. Although they are divided into two groups, in this embodiment, these split images are changed to obtain processed split images (10, 20, and 30). In the processed split image, the center (13, 23) of the pattern area divided by the original pattern border lines (11, 21, 31) of the split image is the part exposed to a constant large amount of light as in the past, and the border lines (11, 21) , 31), the remaining part, which is an area that is not indicated by hatching at a certain width or more, is a part that is not exposed to light as in the past, but in the boundary parts 15 and 25 between these areas, the light dose approaches 0 at the same rate. It is decreasing until now.

Here, the boundary portions 15 and 25 include areas 15b and 25b corresponding to a certain width inside the pattern and areas corresponding to a certain width outside the pattern centered on the pattern boundaries 11, 21 and 31 in the original divided image. 15a, 25a), and the certain width is calculated from the pattern boundary line and the perpendicular direction. Therefore, in this area, the light dose gradually decreases at the same rate from the same size as the light dose shining at the center to 0, going from the inner maximum distance position to the outer maximum distance position.

And here, boundary portions 15 and 25 where the light dose decreases are set throughout the boundary lines 11, 21, and 31 of the pattern of the divided image. In Figure 8, for convenience, it is collectively shown that a border with light dose changes inside and outside the border is formed at the corner where the horizontal line and the vertical line meet. However, the border is an area of a certain width inside and outside in the perpendicular direction only for the straight part of the border. You can set it only so that there is a change in luminous intensity. In this case, the boundary is not set at the corner where lines meet, and therefore the corner extends outside the boundary, leaving no area where the light dose is distributed. This can be understood in the sense that, unlike Figure 8, in the case of a two-dimensionally large pattern, four patterns may overlap at the corner, so the light dose at the corner is distributed taking this into account.

The boundary portions 15 and 25 also include areas 15a and 25a corresponding to a certain width outside the pattern boundary line in all straight sections of the boundary lines 11, 21 and 31, and although the light dose in this area also gradually decreases, the light dose remains constant. Since it must have a non-zero light quantity, if the pattern boundary of the segmented image overlaps the outline of the segmented image, the processed segmented image will exceed the area covered by the original segmented image. That is, the area of the processed segmented image has a part that exceeds the outline of the original segmented image.

Of course, the remainder may be located widely outside the pattern boundary, so that the boundary of the pattern only exists in the pattern area and the remainder area. In this case, the processed segmented image does not extend beyond the area covered by the original segmented image.

In the above situation, when two processed segmented images adjacent to each other are projected onto the two corresponding segmented areas of the substrate, a pattern existing across both of these segmented areas is present in the first processed segmented image 10, as shown in FIG. 8. The boundary portions 15 and 25 of the first pattern portion 12 overlap with the second pattern portion 22 present in the second processed segmented image 20 at adjacent portions.

However, the boundary portions (15, 25) are areas where the light dose gradually decreases from the light dose corresponding to the pattern center (13, 23) to 0, so if the boundaries (15, 25) overlap at the correct width, the light dose at this boundary portion is Even if the light dose of the border 25 of the second pattern part 22 overlaps (adds) to the light dose of the border 15 of the first pattern part 12, the pattern center 13, 23 is present at any position within the border. It has the same luminous dose as that of . As a result, the portion where the boundaries 15, 25 of the processed split pattern portions 12, 22 overlap in the entire pattern area are exposed with the same light dose as the other portions, so there is no significant difference in the pattern state at the border, and split exposure Even in this case, the entire pattern can be naturally reorganized or implemented through a split pattern or partial pattern.

At this time, the portion where the boundary portions 15 of the first pattern portion 12 and the boundary portion 25 of the second pattern portion 22 do not overlap each other increases as the light dose level at the center of the pattern 13 and 23 increases toward the outside. Gradually smaller light doses are allocated, and in the areas where these boundaries are projected, the photosensitive material layer of the substrate forms a pattern only in areas where light doses greater than a certain light dose level are distributed. Therefore, in order for the original pattern shape and the original pattern area boundaries 11, 21, and 31 to be maintained in the etch-stop film pattern, the area exposed to a reference light dose that is half the light dose level at the center of the pattern (13, 23) The light dose level must be set so that the etch mask pattern is formed.

And, even in the case as shown in Figure 10 where the first processed segmented image 10 and the second processed segmented image 20 are not accurately projected onto the corresponding segmented area of the substrate and there is a slight increase in the distance between the two centers. , Conventionally, a gap occurs within the pattern area as shown in Figure 5, but here, the processed segmented image itself is expanded by a certain width compared to the original segmented image, and the pattern area is also extended outward by a certain width due to the presence of the boundary, so the overlapping area is usually This occurs, and the first pattern portion and the second pattern portion overlap slightly at the boundary even if they do not completely overlap. As a result, in the integrated pattern area, there is a portion (f) where the light dose is somewhat reduced compared to other pattern areas, but the degree of reduction is much smaller than in the case where a complete gap is created as shown in Figure 5, and this difference in light dose is An etch mask can also be created in the area where the size is reduced (f).

Conversely, even in the case as shown in FIG. 11 where the first processed segmented image and the second processed segmented image are not accurately projected onto the corresponding segmented area of the substrate and the distance between the two centers is slightly reduced, conventionally, they overlap as shown in FIG. 6. Alternatively, when overlap occurs, the light dose level increases rapidly, but here, the processed segmented image itself expands by a certain amount compared to the original segmented image, but the light dose gradually decreases as it goes outward, so the light dose level usually increases rapidly even in the overlapping area. Instead, there is a part (g) that rises slightly.

For example, the first pattern part and the second pattern part overlap not only at the border, but there may also be a part overlapping with the second pattern part in the center of the first pattern part (area inside the border), but the light dose in this part is very weak. Since it is only one part, the increase in light dose is not large. As a result, in the integrated pattern area, there is a portion (g) where the light dose level rises slightly compared to other pattern areas, but the level of the rise is very small compared to the case where it is completely doubled as shown in Figure 6, and this level of light dose difference Even in areas where the light dose is increased, serious changes in shape, such as an increase in the width of the etch mask, cannot occur.

Meanwhile, in this embodiment, the processed segmented image is first obtained from the entire image, then the processed segmented image is calculated through image processing by considering the entire image, and then projected to the primary digital image projector including the light source. This can be obtained by implementing an image including a pattern with a border using DLP through DMD while the initial image is projected. Of course, in the process of creating a digital image, alternative methods such as transmitting the initial light through the LCD instead of reflecting it from the micromirror of the DMD can be used.

Adjustment or manipulation of individual pixel parts of the DPD for such image processing can be accomplished through data signaling and transmission to the DMD of the processed segmented image calculated through computer image processing. In other words, this computer image processing is performed to set each split image by considering the pattern in the entire image and obtain a processed split image for each split image, and the processed split image obtained in this way is used to obtain the corresponding split image during split exposure. At each sequential exposure, it can be transmitted from the computer to the DPD in the form of a digital data signal and projected onto the substrate.

Therefore, in this case, in a broad sense, both the segmented image and the processed segmented image can be obtained through computer image processing.

The system in which such processed divided image projection is performed is equipped with an overall projector part, including a DMD, that generates a divided image through computer processing, and a lens system that can enlarge and reduce the image constructed by this projector part. It can be done, and a splitter, a reflector, etc. that can split the light into partial reflection and transmission can be provided as needed. Of course, elements such as DMD will be combined with a computer system or other image configuration device that provides image-related signals to control them.

For example, if we explain through an example of a system, separate RGB projection light sources are assumed, and the light source light is projected to the DMD through optical elements such as a reflector, lens, and prism. The projected light source is reflected from the micromirror responsible for each pixel in the DMD, and the micromirror reflects at a predetermined angle through the data signal received from each segmented image processed by image processing equipment such as a computer. Similar to scanning to construct a screen in a display device, projection and reflection of all pixels occur, and a single processed split image is projected focusing on the divided area of the substrate. Through this processed divided image, exposure of the corresponding portion of the substrate is performed. It comes true.

At this time, the processed segmented image, which is usually a combination of the projected light for each pixel reflected from the DMD, has a large area compared to the substrate, so it reaches the substrate in a reduced state at a certain rate through a lens system that acts as a reduction function like a microscope. Then, through exposure, a chemical change occurs in the photosensitive material layer on the substrate to form an etch mask, which is left on the substrate through development. The substrate is placed on the substrate stage and moves in a certain position each time the divided images are sequentially projected.

In order to check and monitor the process status in these exposure operations, the reflected light from the substrate passes through a lens system, a splitter, and is reflected from a reflector to a monitoring imaging device or camera, and a computer that receives signals from this camera. It can be displayed on a display through a processing device.

In the above, the present invention is described through limited examples, but these are merely illustrative descriptions to aid understanding of the present invention and the present invention is not limited to these specific examples.

Accordingly, those skilled in the art will be able to make various modifications and applications based on the present invention, and it is natural that such modifications and applications fall within the scope of the appended patent claims.

10, 20, 30: Processed segmented image 11, 21`, 31: Borderline (pattern borderline)
12: first pattern part 13, 23: center
15, 25: border 22: second pattern part

Claims (5)

In carrying out a split exposure method in which each split image obtained by dividing the overall image into regions in a maskless digital photolithography process is sequentially transferred to the substrate for each divided region,
Among the borderlines of the pattern area, which is the area where light is irradiated within each split image, a range is set to have a certain width each inside and outside around the borderline at least in the section connected to the pattern area of the adjacent split image, and within the range Forms a processed segmented image with the amount of light or optical dose gradually reduced from the inside to the outside,
A process of exposing a corresponding divided area on the substrate using the processed divided image,
The light dose at a boundary portion corresponding to a certain width range inside and outside the boundary line of the pattern area of the processed divided image is gradually reduced from the light dose level for the pattern area before processing to 0,
The certain width is calculated in the direction perpendicular to the boundary line of the pattern area, and the exposure area of a certain width is not expanded outward at the corners of the pattern area to prevent exposure by light irradiation,
The processed divided image is expanded outward by a certain width around the pattern boundary of the divided image in the section, and the processed divided image is projected onto a substrate with an area slightly larger than the corresponding divided area of the divided image,
The operation of forming a processed segmented image by adjusting the light dose at a certain width inside and outside around the borderline of the pattern area is performed in all borderline sections of the pattern area, but the light dose is adjusted at a certain width inside and outside around the borderline. The area to be adjusted includes a boundary section, and the section is added or subtracted around the section to reduce the light dose by a certain amount for all pattern boundaries,
The light dose is such that the photosensitive material layer is effectively exposed to the exposed area at a light dose level that is more than half of the light dose level for the pattern area before processing, so that the exposure is performed in an amount that forms a mask for the process,
The processed segmented image is implemented as an image including a pattern having a border using DLP (digital light processing) through a DMD (digital micromirror device) with the initial light beam projected by a primary digital image projector including a light source. An exposure method characterized in that:
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