JP2022126438A - Line segment image creating method and line segment image creating device - Google Patents

Abstract

PURPOSE: To provide a device and method that can create an image of a fine line segment.CONSTITUTION: A line segment image creating method according to one aspect of the present invention is a line segment image creating method for creating a two-dimensional image of a desired line segment, the method comprising: a step of creating a wide line segment having a width of one pixel size or more in a normal direction of a desired line segment, centered on the desired line segment; and a step of setting the gray scale value of each pixel on the basis of a positional relationship between the created wide line segment and a plurality of pixels constituting an image of a predetermined size, and then outputting image data in which the gray scale value of each pixel is set.SELECTED DRAWING: Figure 7

Description

One aspect of the present invention relates to a line segment image creation method and a line segment image creation device. For example, the present invention relates to an image forming apparatus and method for drawing a contour line of a figure as an image composed of a plurality of pixels whose gradation values are defined.

2. Description of the Related Art In recent years, as large-scale integrated circuits (LSIs) have become highly integrated and have large capacities, the circuit line width required for semiconductor elements has become increasingly narrow. In addition, the improvement of yield is essential for the manufacture of LSIs, which requires a great manufacturing cost. However, patterns constituting LSIs are approaching the order of 10 nanometers or less, and the dimensions that must be detected as pattern defects are extremely small. Therefore, there is a need to improve the precision of a pattern inspection apparatus for inspecting defects in an ultrafine pattern transferred onto a semiconductor wafer. In addition, one of the major factors that lower the yield is the pattern defect of the mask used when exposing and transferring the ultra-fine pattern onto the semiconductor wafer by photolithography technology. Therefore, it is necessary to improve the precision of pattern inspection apparatuses for inspecting defects in transfer masks used in LSI manufacturing.

As a defect inspection method, inspection is performed by comparing a measurement image of a pattern formed on a substrate such as a semiconductor wafer or a lithography mask with a measurement image of design data or the same pattern on the substrate. It is known how to do For example, a contour line is extracted from a figure in an image to be inspected (see, for example, Patent Document 1). Then, the inspection is performed by comparing the extracted contour lines of the image to be inspected with the reference contour lines.

Here, when the data of the extracted contour line is defined as vector data for each pixel, for example, the distance from the center of each pixel to the contour line and the angle of the normal direction of the contour line are defined. As a result, the data amount of each pixel becomes larger than the data amount of the image data. Therefore, in order to reduce the amount of data, it is required to define contour line data as image data.

On the other hand, when creating a contour line image, the contour line is defined by the gradation value of each pixel. For example, it is defined as a binary value in which a pixel through which the contour line passes is 1 (or the maximum gradation value) and a pixel through which the contour line does not pass is 0. Therefore, in the case of a line segment that extends diagonally with respect to the arrangement direction of a plurality of pixels arranged in a grid pattern, the line segment is not drawn as a straight line in the image of the contour line, but is drawn as a stepped line. was there. Furthermore, when the outline is imaged, the gradation value is defined in units of pixels, so positional information in units of sub-pixels smaller than the pixel size may be lost. Therefore, for example, even if the position of the contour line can be extracted with high accuracy from the figure in the image to be inspected, there is a problem that the position of the contour line is shifted when the contour line is imaged afterward. As a result, accurate comparison of contours becomes difficult. Therefore, it is required to create a fine contour line image. Such problems are not limited to inspection devices. A similar problem arises when creating a two-dimensional image of a line segment.

JP 2011-48592 A

One aspect of the present invention provides an apparatus and method capable of creating images of fine line segments.

A line segment image creation method according to one aspect of the present invention includes:
A line segment image creation method for creating a two-dimensional image of a desired line segment,
creating a wide line segment centered on the desired line segment and having a width of one pixel size or more in the normal direction of the desired line segment;
A gradation value for each pixel is set based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size, and image data in which the gradation value for each pixel is set is output. process and
characterized by comprising

Further, as a positional relationship, the step of calculating the area ratio of the wide line segment included in the target pixel for each pixel,
It is preferable that the gradation value of each pixel is set according to the area ratio of the target pixel.

Further comprising a step of calculating a value obtained by multiplying a preset maximum gradation value by an area ratio of the target pixel,
Preferably, the gradation value of each pixel is set to a value obtained by multiplying a preset maximum gradation value by the area ratio of the target pixel.

Further, it is preferable to set the maximum width of a wide line segment to a width size that is equal to or greater than one pixel size and that does not include other wide line segments in pixels adjacent to pixels overlapping the wide line segment. be.

A line segment image creation device according to one aspect of the present invention includes:
A line segment image creating device for creating a two-dimensional image of a desired line segment,
a wide line segment creation unit for creating a wide line segment having a width of one pixel size or more in the normal direction of the desired line segment centered on the desired line segment;
A gradation value for each pixel is set based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size, and image data in which the gradation value for each pixel is set is output. a gradation value setting unit;
characterized by comprising

According to one aspect of the present invention, a two-dimensional image of fine line segments can be created.

1 is a configuration diagram showing an example of the configuration of a pattern inspection apparatus according to Embodiment 1; FIG. FIG. 2 is a conceptual diagram showing the configuration of a shaping aperture array substrate according to Embodiment 1; 4 is a diagram showing an example of a plurality of chip regions formed on the semiconductor substrate according to Embodiment 1; FIG. FIG. 4 is a diagram for explaining a multi-beam scanning operation according to Embodiment 1; FIG. 10 is a diagram showing an example of creating a two-dimensional image of a line segment in Comparative Example 1 of Embodiment 1; FIG. 10 is a diagram showing an example of creating a two-dimensional image of a line segment in Comparative Example 2 of Embodiment 1; FIG. 2 is a flow chart showing main steps of an inspection method according to Embodiment 1; 2 is a block diagram showing an example of the internal configuration of a comparison circuit according to Embodiment 1; FIG. 4 is a diagram showing an example of a line segment according to Embodiment 1; FIG. 4 is a diagram showing an example of a wide line segment according to Embodiment 1; FIG. 4 is a diagram showing an example of two adjacent wide line segments according to Embodiment 1. FIG. FIG. 4 is a diagram showing an example of the area ratio of wide line segments according to Embodiment 1; 4 is a diagram showing an example of image data of a line segment image according to Embodiment 1. FIG. 4 is a diagram showing an example of a positional relationship between an actual image contour line and a reference contour line in Embodiment 1. FIG. FIG. 10 is a diagram showing an example of data amounts in Embodiment 1 and Comparative Example 3;

In the following embodiments, an electron beam inspection device will be described as an example of a line segment image generation device and/or a pattern inspection device. However, it is not limited to this. For example, it may be an inspection apparatus that irradiates a substrate to be inspected with ultraviolet rays and acquires an image to be inspected using light that is transmitted through or reflected by the substrate to be inspected. Also, in the embodiments, an inspection apparatus that acquires an image using a multi-beam consisting of a plurality of electron beams will be described, but the present invention is not limited to this. It may be an inspection apparatus that obtains an image using a single electron beam. Further, the line segment image creation device is not limited to the inspection device, and may be any device that images a line segment. For example, it may be a server device and/or a terminal device equipped with a computer.

Embodiment 1.
FIG. 1 is a configuration diagram showing an example of the configuration of a pattern inspection apparatus according to Embodiment 1. FIG. In FIG. 1, an inspection apparatus 100 for inspecting a pattern formed on a substrate is an example of a multi-electron beam inspection apparatus. The inspection apparatus 100 includes an image acquisition mechanism 150 (secondary electronic image acquisition mechanism) and a control system circuit 160 . The image acquisition mechanism 150 includes an electron beam column 102 (electron lens barrel) and an inspection room 103 . Inside the electron beam column 102 are an electron gun 201, an electromagnetic lens 202, a shaping aperture array substrate 203, an electromagnetic lens 205, a batch blanking deflector 212, a limiting aperture substrate 213, an electromagnetic lens 206, an electromagnetic lens 207 (objective lens), A main deflector 208, a sub-deflector 209, a beam separator (E×B separator) 214, a deflector 218, an electromagnetic lens 224, an electromagnetic lens 226, and a multi-detector 222 are arranged. In the example of FIG. 1, an electron gun 201, an electromagnetic lens 202, a shaping aperture array substrate 203, an electromagnetic lens 205, a batch blanking deflector 212, a limiting aperture substrate 213, an electromagnetic lens 206, an electromagnetic lens 207 (objective lens), a main deflection The device 208 and sub-deflector 209 constitute a primary electron optical system for irradiating the substrate 101 with multiple primary electron beams. The beam separator 214 , deflector 218 , electromagnetic lens 224 , and electromagnetic lens 226 constitute a secondary electron optical system that irradiates the multiple secondary electron beams onto the multiple detector 222 .

A stage 105 movable at least in the XY directions is arranged in the examination room 103 . A substrate 101 (sample) to be inspected is placed on the stage 105 . The substrate 101 includes an exposure mask substrate and a semiconductor substrate such as a silicon wafer. When the substrate 101 is a semiconductor substrate, a plurality of chip patterns (wafer dies) are formed on the semiconductor substrate. When the substrate 101 is an exposure mask substrate, a chip pattern is formed on the exposure mask substrate. A chip pattern is composed of a plurality of graphic patterns. A plurality of chip patterns (wafer dies) are formed on the semiconductor substrate by exposing and transferring the chip patterns formed on the mask substrate for exposure a plurality of times onto the semiconductor substrate. The following mainly describes the case where the substrate 101 is a semiconductor substrate. The substrate 101 is placed on the stage 105, for example, with the pattern formation surface facing upward. A mirror 216 is arranged on the stage 105 to reflect the laser beam for laser length measurement emitted from the laser length measurement system 122 arranged outside the inspection room 103 . A multi-detector 222 is connected to the detection circuit 106 external to the electron beam column 102 .

In the control system circuit 160, a control computer 110 that controls the entire inspection apparatus 100 is connected via a bus 120 to a position circuit 107, a comparison circuit 108, a reference contour line extraction circuit 112, a stage control circuit 114, a lens control circuit 124, a block It is connected to a ranking control circuit 126 , a deflection control circuit 128 , a storage device 109 such as a magnetic disk device, a monitor 117 and a memory 118 . The deflection control circuit 128 is also connected to DAC (digital to analog conversion) amplifiers 144 , 146 and 148 . The DAC amplifier 146 is connected to the main deflector 208 and the DAC amplifier 144 is connected to the sub deflector 209 . DAC amplifier 148 is connected to deflector 218 .

The detection circuit 106 is also connected to the chip pattern memory 123 . Chip pattern memory 123 is connected to comparison circuit 108 . Also, the stage 105 is driven by a drive mechanism 142 under the control of the stage control circuit 114 . In the drive mechanism 142, for example, a drive system such as a three-axis (XY-.theta.) motor that drives in the X, Y and .theta. It's becoming These X motor, Y motor, and θ motor (not shown) can be stepping motors, for example. The stage 105 can be moved in horizontal and rotational directions by motors on the XY and .theta. axes. The movement position of the stage 105 is measured by the laser length measurement system 122 and supplied to the position circuit 107 . The laser length measurement system 122 measures the position of the stage 105 based on the principle of laser interferometry by receiving reflected light from the mirror 216 . In the stage coordinate system, for example, the X direction, Y direction, and θ direction are set with respect to a plane orthogonal to the optical axis (electron orbit central axis) of the multi-primary electron beams.

The electromagnetic lens 202 , the electromagnetic lens 205 , the electromagnetic lens 206 , the electromagnetic lens 207 (objective lens), the electromagnetic lens 224 , the electromagnetic lens 226 and the beam separator 214 are controlled by the lens control circuit 124 . The collective blanking deflector 212 is composed of two or more electrodes, and each electrode is controlled by the blanking control circuit 126 via a DAC amplifier (not shown). The sub-deflector 209 is composed of four or more electrodes, and is controlled by the deflection control circuit 128 via the DAC amplifier 144 for each electrode. The main deflector 208 is composed of four or more electrodes, and is controlled by the deflection control circuit 128 through the DAC amplifier 146 for each electrode. The deflector 218 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 128 via the DAC amplifier 148 .

A high-voltage power supply circuit (not shown) is connected to the electron gun 201, and an acceleration voltage is applied from the high-voltage power supply circuit between a filament (cathode) and an extraction electrode (anode) (not shown) in the electron gun 201, and another extraction electrode is applied. A group of electrons emitted from the cathode is accelerated by application of a (Wehnelt) voltage and heating of the cathode to a predetermined temperature, and is emitted as an electron beam 200 .

Here, FIG. 1 describes the configuration necessary for explaining the first embodiment. The inspection apparatus 100 may have other configurations that are normally required.

FIG. 2 is a conceptual diagram showing the configuration of the shaping aperture array substrate according to the first embodiment. In FIG. 2, the shaping aperture array substrate 203 has a two-dimensional shape of m ₁ rows (x direction) x n ₁ rows (y direction) (one of m ₁ and n ₁ is an integer of 2 or more and the other is Integer of 1 or more) holes (openings) 22 are formed at a predetermined array pitch in the x and y directions. The example of FIG. 2 shows a case where 23×23 holes (openings) 22 are formed. Each hole 22 is ideally formed as a rectangle of the same size and shape. Alternatively, ideally, they may be circular with the same outer diameter. A portion of the electron beam 200 passes through each of the plurality of holes 22 to form m ₁ ×n ₁ (=N) multiple primary electron beams 20 .

Next, operation of the image acquisition mechanism 150 in the inspection apparatus 100 will be described.

An electron beam 200 emitted from an electron gun 201 (emission source) is refracted by an electromagnetic lens 202 to illuminate the entire shaped aperture array substrate 203 . A plurality of holes 22 (openings) are formed in the shaping aperture array substrate 203, as shown in FIG. The multiple primary electron beams 20 are formed by each part of the electron beam 200 irradiated to the positions of the plurality of holes 22 passing through the plurality of holes 22 of the shaped aperture array substrate 203 .

The formed multiple primary electron beams 20 are refracted by the electromagnetic lens 205 and the electromagnetic lens 206, respectively, and arranged at intermediate image plane positions of each beam of the multiple primary electron beams 20 while repeating intermediate images and crossovers. 214 to the electromagnetic lens 207 (objective lens). The electromagnetic lens 207 then focuses the multiple primary electron beams 20 onto the substrate 101 . A multi-primary electron beam 20 focused (focused) on the substrate 101 (specimen) plane by an objective lens 207 is collectively deflected by a main deflector 208 and a sub-deflector 209, and the substrate of each beam is Each irradiation position on 101 is irradiated. When the entire multi-primary electron beam 20 is collectively deflected by the collective blanking deflector 212 , it is displaced from the center hole of the limiting aperture substrate 213 and shielded by the limiting aperture substrate 213 . On the other hand, the multi-primary electron beams 20 not deflected by the collective blanking deflector 212 pass through the center hole of the limiting aperture substrate 213 as shown in FIG. Blanking control is performed by turning ON/OFF the batch blanking deflector 212, and ON/OFF of the beam is collectively controlled. Thus, the limiting aperture substrate 213 shields the multiple primary electron beams 20 that are deflected by the collective blanking deflector 212 to a beam-OFF state. A multiple primary electron beam 20 for inspection (for image acquisition) is formed by a group of beams that have passed through the limiting aperture substrate 213 and are formed from the time the beam is turned ON until the beam is turned OFF.

When a desired position of the substrate 101 is irradiated with the multiple primary electron beams 20, each beam of the multiple primary electron beams 20 from the substrate 101 corresponds to the irradiation of the multiple primary electron beams 20. , a bundle of secondary electrons (multi secondary electron beam 300) including reflected electrons is emitted.

A multi-secondary electron beam 300 emitted from substrate 101 passes through electromagnetic lens 207 to beam separator 214 .

Here, the beam separator 214 (E×B separator) has a plurality of magnetic poles of two or more poles using coils and a plurality of electrodes of two or more poles. A directional magnetic field is generated by the plurality of magnetic poles. Similarly, a plurality of electrodes generate a directional electric field. Specifically, the beam separator 214 generates an electric field and a magnetic field in orthogonal directions on a plane orthogonal to the direction in which the central beam of the multi primary electron beam 20 travels (orbit center axis). The electric field exerts a force in the same direction regardless of the electron's direction of travel. On the other hand, the magnetic field exerts a force according to Fleming's left-hand rule. Therefore, the direction of the force acting on the electrons can be changed depending on the electron penetration direction. In the multi-beam 20 entering the beam separator 214 from above, the force due to the electric field and the force due to the magnetic field cancel each other out, and the multi-primary electron beam 20 travels straight downward. On the other hand, the force due to the electric field and the force due to the magnetic field act in the same direction on the multiple secondary electron beam 300 entering the beam separator 214 from below, and the multiple secondary electron beam 300 moves obliquely upward. It is bent and separated from the trajectory of the multi primary electron beam 20 .

The multi-secondary electron beam 300 bent obliquely upward and separated from the multi-primary electron beam 20 is further bent by the deflector 218 and projected onto the multi-detector 222 while being refracted by the electromagnetic lenses 224 and 226. be. A multi-detector 222 detects the projected multi-secondary electron beam 300 . Backscattered electrons and secondary electrons may be projected onto the multi-detector 222 , or secondary electrons remaining after diverging backscattered electrons may be projected onto the multi-detector 222 . Multi-detector 222 has a two-dimensional sensor. Each secondary electron of the multi-secondary electron beam 300 collides with a corresponding region of the two-dimensional sensor to generate electrons and generate secondary electron image data for each pixel. In other words, a detection sensor is arranged in the multi-detector 222 for each primary electron beam of the multi-primary electron beam 20 . Then, the corresponding secondary electron beam emitted by the irradiation of each primary electron beam is detected. Therefore, each detection sensor of the plurality of detection sensors of the multi-detector 222 detects the intensity signal of the secondary electron beam for imaging caused by the irradiation of the primary electron beam in charge. The intensity signal detected by the multi-detector 222 is output to the detection circuit 106 .

FIG. 3 is a diagram showing an example of a plurality of chip regions formed on the semiconductor substrate according to the first embodiment. In FIG. 3, when the substrate 101 is a semiconductor substrate (wafer), a plurality of chips (wafer dies) 332 are formed in a two-dimensional array in an inspection area 330 of the semiconductor substrate (wafer). A mask pattern for one chip formed on an exposure mask substrate is transferred to each chip 332 after being reduced to 1/4, for example, by an exposure device (stepper, scanner, etc.) not shown. A region of each chip 332 is divided into a plurality of stripe regions 32 with a predetermined width in the y direction, for example. The scanning operation by the image acquisition mechanism 150 is performed for each stripe region 32, for example. For example, while moving the stage 105 in the -x direction, the scanning operation of the stripe region 32 is relatively advanced in the x direction. Each stripe region 32 is divided into a plurality of rectangular regions 33 in the longitudinal direction. The movement of the beam to the target rectangular area 33 is performed by collective deflection of the entire multi-primary electron beam 20 by the main deflector 208 .

FIG. 4 is a diagram for explaining a multi-beam scanning operation according to the first embodiment. The example of FIG. 4 shows the case of the multi-primary electron beams 20 arranged in 5×5 rows. The irradiation area 34 that can be irradiated by one irradiation of the multi primary electron beams 20 is (the x direction obtained by multiplying the beam pitch in the x direction of the multi primary electron beams 20 on the surface of the substrate 101 by the number of beams in the x direction. size)×(the y-direction size obtained by multiplying the inter-beam pitch in the y-direction of the multi-primary electron beams 20 on the substrate 101 surface by the number of beams in the y-direction). It is preferable to set the width of each stripe region 32 to the same size as the y-direction size of the irradiation region 34, or to a size narrower by the scan margin. The examples of FIGS. 3 and 4 show the case where the irradiation area 34 has the same size as the rectangular area 33 . However, it is not limited to this. The irradiation area 34 may be smaller than the rectangular area 33 . Or it doesn't matter if it's big. Each beam of the multi-primary electron beam 20 is irradiated within a sub-irradiation region 29 surrounded by the beam-to-beam pitch in the x-direction and the beam-to-beam pitch in the y-direction where the beam is positioned. Scan (scanning operation) inside. Each of the primary electron beams 10 forming the multi-primary electron beam 20 is in charge of any sub-irradiation region 29 different from each other. In each shot, each primary electron beam 10 irradiates the same position within the assigned sub-irradiation region 29 . Movement of the primary electron beam 10 within the sub-irradiation region 29 is performed by collective deflection of the entire multi-primary electron beam 20 by the sub-deflector 209 . Such an operation is repeated to sequentially irradiate one sub-irradiation region 29 with one primary electron beam 10 . When the scanning of one sub-irradiation region 29 is completed, the main deflector 208 collectively deflects the entire multi-primary electron beam 20 to move the irradiation position to the adjacent rectangular region 33 within the same stripe region 32 . Such an operation is repeated to sequentially irradiate the inside of the stripe region 32 . After the scanning of one stripe region 32 is completed, the irradiation position moves to the next stripe region 32 by moving the stage 105 and/or collectively deflecting the entire multi-primary electron beam 20 by the main deflector 208 . As described above, a secondary electron image is acquired for each sub-irradiation area 29 by irradiation with each primary electron beam 10 . A secondary electron image of the rectangular area 33 , a secondary electron image of the striped area 32 , or a secondary electron image of the chip 332 is constructed by combining the secondary electron images of the respective sub-irradiation areas 29 .

As shown in FIG. 4, each sub-irradiation area 29 is divided into a plurality of rectangular frame areas 30, and a secondary electron image (image to be inspected) of each frame area 30 is used for inspection. The example of FIG. 4 shows a case where one sub irradiation area 29 is divided into four frame areas 30, for example. However, the number of divisions is not limited to four. It may be divided into other numbers.

For example, it is also possible to group a plurality of chips 332 arranged in the x-direction into the same group and divide each group into a plurality of stripe regions 32 with a predetermined width in the y-direction. Further, the movement between the stripe regions 32 is not limited to each chip 332, and may be preferably performed for each group.

Here, when the substrate 101 is irradiated with the multi primary electron beams 20 while the stage 105 is continuously moving, the main deflector 208 collectively deflects the irradiation position of the multi primary electron beams 20 so as to follow the movement of the stage 105 . A tracking operation is performed by Therefore, the emission positions of the multi-secondary electron beams 300 change every second with respect to the orbital central axis of the multi-primary electron beams 20 . Similarly, when scanning the sub-irradiation region 29, the emission position of each secondary electron beam changes within the sub-irradiation region 29 every moment. The deflector 218 collectively deflects the multi-secondary electron beams 300 so that the secondary electron beams whose emission positions are changed in this way are irradiated in the corresponding detection regions of the multi-detector 222 . Alternatively, a deflector (not shown) is placed on the secondary electron beam trajectory closer to the multi-detector 222 than the deflector 218, and each secondary electron beam is directed to the multi-detector 222 by following the change in the emission position. The multiple secondary electron beams 300 may be collectively deflected so as to irradiate the corresponding detection regions.

FIG. 5 is a diagram showing an example of creating a two-dimensional image of a line segment in Comparative Example 1 of Embodiment 1. FIG. In Comparative Example 1, when the straight line segment 40 shown in FIG. 5A is to be imaged, the line segment 40 and a plurality of pixels forming the image are overlapped. In the example of FIG. 5A, for example, 3×3 pixels 36 are shown. Then, as shown in FIG. 5(b), it is defined as a binary value in which a pixel through which the line segment passes is 1 (or the maximum grayscale value) and a pixel through which the line segment does not pass is 0. Therefore, in the case of a line segment extending diagonally with respect to the arrangement direction of the plurality of pixels 36 arranged in a grid pattern, the line segment does not become a straight line as shown in FIG. It is drawn as a line that bends into a shape.

FIG. 6 is a diagram illustrating an example of creating a two-dimensional image of a line segment in Comparative Example 2 of Embodiment 1. FIG. In the example of FIG. 6A, for example, 3×3 pixels 36 are shown. As shown in FIG. 6A, in Comparative Example 2, for example, a straight line segment 40 passes through only the central pixel row among three pixel rows arranged in the x direction. In this case, as shown in FIG. 6B, the gradation value of three pixels 36 in the central pixel row among the three pixel rows arranged in the x direction becomes 1 (or the maximum gradation value). The gradation value of the other pixels 36 through which light cannot pass is zero. In the image data in which the gradation values shown in FIG. 6(b) are defined, a line segment 40-1 extending in an oblique direction is a line segment passing through the central pixel row as shown in FIG. 6(c). For example, a line segment 40-2 extending in the y direction near the right end of the central pixel column is also included. In other words, when the line segment 40 is imaged, the gradation value is defined in units of pixels, so position information in units of sub-pixels smaller than the pixel size is lost. Therefore, in Comparative Example 2, the position of the line segment 40 shifts when the line segment 40 is imaged. Therefore, if the contour line inspection is performed as it is, it will be difficult to accurately compare the contour lines. Therefore, it is required to create a fine line segment image.

FIG. 7 is a flow chart showing main steps of the inspection method according to the first embodiment. 7, the inspection method in Embodiment 1 includes a scanning step (S102), a frame image creating step (S104), an actual image contour line extraction step (S106), a reference contour line extraction step (S110), A series of steps including an actual contour image creation step (S120), a reference contour image creation step (S130), and a comparison step (S140) are performed.

The actual image contour image creating step (S120) includes, as internal steps, an actual image line segment creating step (S122), an actual image line segment width increasing step (actual image wide line segment creating step) (S124), and an actual image line segment creating step (S122). A series of steps including an area ratio calculation step (S126), an actual image gradation value calculation step (S127), an actual image gradation value setting step (S128), and a judgment step (S129) is performed.

The reference contour image creating step (S130) includes, as internal steps, a reference line segment creating step (S132), a reference line segment width enlarging step (reference wide line segment creating step) (S134), and a reference area ratio calculating step ( S136), reference tone value calculation step (S137), reference tone value setting step (S138), and determination step (S139) are performed.

An actual image line segment creation step (S122), an actual image line segment width enlargement step (wide line segment creation step) (S124), an actual image area ratio calculation step (S126), and an actual image tone value calculation step (S127). ), the actual image gradation value setting step (S128), and the determination step (S129) are examples of essential steps of the line segment image creation method. Similarly, the reference line segment creating step (S132), the reference line segment width enlarging step (reference wide line segment creating step) (S134), the reference area ratio calculating step (S136), and the reference tone value calculating step (S137). ), the reference tone value setting step (S138), and the determination step (S139) are other examples of essential steps of the line segment image creation method.

As the scanning step (S102), the image acquisition mechanism 150 acquires an image of the substrate 101 on which the figure pattern is formed. Here, a substrate 101 formed with a plurality of figure patterns is irradiated with a multi-primary electron beam 20, and a multi-secondary electron beam 300 emitted from the substrate 101 due to the irradiation of the multi-primary electron beam 20 is generated. A secondary electron image of the substrate 101 is acquired by the detection. As described above, backscattered electrons and secondary electrons may be projected onto the multi-detector 222, or the secondary electrons (multi-secondary electron beam 300) remaining after divergence of the backscattered electrons may be projected onto the multi-detector 222. May be.

As described above, the multi-secondary electron beams 300 emitted from the substrate 101 due to the irradiation of the multi-primary electron beams 20 are detected by the multi-detector 222 . Secondary electron detection data (measurement image data: secondary electron image data: inspection image data) for each pixel in each sub-irradiation region 29 detected by the multi-detector 222 is output to the detection circuit 106 in the order of measurement. be. In the detection circuit 106 , the analog detection data is converted into digital data by an A/D converter (not shown) and stored in the chip pattern memory 123 . The obtained measurement image data is transferred to the comparison circuit 108 together with information indicating each position from the position circuit 107 .

FIG. 8 is a block diagram showing an example of the internal configuration of the comparison circuit according to the first embodiment. 8, the comparison circuit 108 in the first embodiment includes storage devices 50, 52, 56, 57 such as magnetic disk devices, a frame image creating unit 54, an actual image contour line extracting unit 58, an actual image contour line image A creation unit 60, a reference contour image creation unit 70, and a comparison processing unit 84 are arranged. The actual contour line image creating unit 60 is an example of a line segment image creating device. Similarly, the reference contour image generator 70 is another example of a line segment image generator.

The actual image outline image generating unit 60 includes an actual image line segment generating unit 62, an actual image wide line segment generating unit 64, an actual image area ratio calculating unit 66, an actual image gradation value calculating unit 67, an actual image gradation A value setting unit 68 and a determination unit 69 are arranged.

The reference contour line image creating unit 70 includes a reference line segment creating unit 72, a reference wide line segment creating unit 74, a reference area ratio calculating unit 76, a reference tone value calculating unit 77, a reference tone value setting unit 78, and A determination unit 79 is arranged.

Frame image creating unit 54, real image outline extracting unit 58, real image outline image creating unit 60 (real image line segment creating unit 62, real image wide line segment creating unit 64, real image area ratio calculating unit 66, real image gradation value calculation unit 67, actual image gradation value setting unit 68, and determination unit 69), reference contour line image creation unit 70 (reference line segment creation unit 72, reference wide line segment creation unit 74, reference area ratio calculation unit 76, reference gradation value calculation unit 77, reference gradation value setting unit 78, and determination unit 79), and comparison processing unit 84 each include a processing circuit, and the processing circuit includes an electric circuit. , computers, processors, circuit boards, quantum circuits, or semiconductor devices. Also, each of the "-units" may use a common processing circuit (same processing circuit). Alternatively, different processing circuits (separate processing circuits) may be used. Frame image creating unit 54, real image outline extracting unit 58, real image outline image creating unit 60 (real image line segment creating unit 62, real image wide line segment creating unit 64, real image area ratio calculating unit 66, real image gradation value calculation unit 67, actual image gradation value setting unit 68, and determination unit 69), reference contour line image creation unit 70 (reference line segment creation unit 72, reference wide line segment creation unit 74, reference area ratio calculation unit 76, reference gradation value calculation unit 77, reference gradation value setting unit 78, and determination unit 79) and comparison processing unit 84. Necessary input data or calculation results are stored in a memory (not shown) or memory 118 each time. stored in

The measured image data (scanned image) transferred to the comparison circuit 108 is stored in the storage device 50 .

In the frame image creation step (S104), the frame image creation unit 54 divides the image data of the sub-irradiation regions 29 acquired by the scanning operation of each primary electron beam 10 into a plurality of frame regions 30 for each frame region 30. frame image 31 is created. It should be noted that each frame area 30 is preferably configured such that the margin areas overlap each other so that there is no missing image. The created frame image 31 is stored in the storage device 56 .

As the actual image outline extraction step (S106), the actual image outline extraction unit 58 extracts, for each frame image 31, a plurality of outline positions (actual image outline positions) of each figure pattern in the frame image 31 concerned. A conventional method may be used to extract the contour position. For example, a differentiation filter such as a Sobel filter is used to differentiate each pixel in the x and y directions, and a contour is extracted based on the primary differential values in the x and y directions. At this time, when the primary differential value exceeds a certain value, it is determined to be a contour, and the peak position of the profile of the primary differential value is extracted in units of sub-pixels as the contour position on the contour line (real image contour line). As a result, the actual image contour line extraction unit 58 extracts the actual image contour line. Information (actual image contour line data) on the extracted actual image contour line is stored in the storage device 57 . The actual image contour line data is preferably defined for each pixel by the distance d from the center of the pixel and the angle θ of the normal direction of the contour line. The normal angle θ is defined, for example, as a clockwise angle with respect to the x-axis. The distance d and the angle .theta. may be defined as NULL information for pixels through which the contour line does not pass.

As a reference contour extraction step (S110), the reference contour extraction circuit 112 extracts a reference contour for comparison with the actual image contour. For example, first, a plurality of reference contour positions are extracted, and a reference contour is extracted from the plurality of reference contour positions. The reference contour position may be extracted from the design data, or alternatively, first, a reference image is created from the design data, and the reference image is used to refer to the frame image 31, which is the measurement image. It is also possible to extract contour positions. Alternatively, other conventional methods may be used to extract a plurality of reference contour positions. Design data is stored in the storage device 109 . The design data defines a graphic code indicating the coordinates (x, y) of the reference point of each graphic pattern, size, and graphic type. Alternatively, it is preferable that each vertex coordinate of each figure pattern is defined.

Information on the extracted reference contour (reference contour data) is output to the comparison circuit 108 . Within the comparison circuit 108, the reference contour line data is stored in the storage device 52. FIG. The reference contour line data is preferably defined for each pixel by the distance d from the center of the pixel and the angle θ of the normal direction of the contour line. The normal angle θ is defined, for example, as a clockwise angle with respect to the x-axis. The distance d and the angle .theta. may be defined as NULL information for pixels through which the contour line does not pass.

The obtained reference contour line data is output to the comparison circuit 108 . The comparison circuit 108 stores the reference contour line data in the storage device 52 .

As the actual image contour line image creating step (S120), the actual image outline image creating unit 60 uses the actual image outline data to create an actual image outline image. Specifically, it operates as follows.

In the actual image line segment creation step (S122), the actual image line segment creation unit 62 divides the target contour line into straight lines of a predetermined length for each contour line in the frame area 30, and determines the start point of the straight line. At least one line segment (actual line segment) is created by finding the end point.

9 is a diagram showing an example of a line segment according to Embodiment 1. FIG. A contour line 41 shown in FIG. 9A is divided into a plurality of line segments 40a and 40b shown in FIG. 9B. The outline is divided so that the length of the straight line is, for example, the total length of the pixel size of several pixels. Fractional lengths of line segments less than the prescribed length may be generated. It is preferable to set the prescribed length of the line segment to approximately the size of the past defect location.

As the actual image line segment width enlarging process (actual image wide line segment creation process) (S124), the actual image wide line segment creation unit 64 creates a line segment by 1 pixel in the normal direction of the desired line segment centered on the desired line segment. Create a wide line segment with a width equal to or larger than the size.

10 is a diagram showing an example of a wide line segment according to Embodiment 1. FIG. In Embodiment 1, when the straight line segment 40 shown in FIG. 10A is to be imaged, the line segment 40 and the plurality of pixels 36 forming the image are overlapped. In the example of FIG. 10A, for example, 3×3 pixels 36 are shown among a plurality of pixels 36 forming an image. Since the line segment 40 itself does not have a normal width defined, each position on the line segment is located within any one pixel 36 . Therefore, the line segment 40 is imaged based on the information of only the pixels through which the line segment 40 passes. In other words, when the line segment is imaged, it is not affected by adjacent pixels that the line segment does not pass through. In other words, when a line segment is imaged, it cannot be corrected by adjacent pixels that the line segment does not pass through. Therefore, in Embodiment 1, as shown in FIG. 10B, a wide line segment 42 is created by enlarging the width size W in the normal direction of the line segment to a size of 1 pixel or more. As a result, each position in the direction in which the line segment 40 extends can overlap with at least one pixel or more in the normal direction. For example, each position in the direction in which the line segment 40 extends can overlap two pixels in the normal direction.

11 is a diagram showing an example of two adjacent wide line segments according to Embodiment 1. FIG. When enlarging the width of the line segment 40 in the normal direction to a size of one pixel or more, a limitation occurs in the case where a plurality of line segments 40 exist nearby. In the first embodiment, the maximum width of the wide line segment 42 is a width size equal to or greater than one pixel size and not including other wide line segments 44 in the pixels adjacent to the pixels overlapping the wide line segment 42. is set. In other words, as shown in the example of FIG. 11, the maximum width size is set so that one pixel remains between the wide line segment 42 and the wide line segment 44 so that none of the wide line segments overlap. In other words, the maximum width Wmax that can be expanded is defined by Wmax=D−1 using the distance D between two adjacent line segments. Note that the distance D is defined using the pixel size as a unit size. For example, if the distance D between two adjacent lines is the size of 3 pixels, the maximum width Wmax=3-1=2 pixels size. In the example of FIG. 11, for example, two line segments (dotted lines) with a distance D of 2.6 pixels between two adjacent line segments are shown. In this case, the maximum width Wmax of the wide line segments 42 and 44 expanding the two line segments (dotted lines) is 2.6-1=1.6 pixel size (1.6 times the pixel size).

As the actual screen area ratio calculation step (S126), the actual screen area ratio calculator 66 calculates the area ratio of the wide line segment 42 included in the target pixel for each of the plurality of pixels 36 forming the image.

FIG. 12 is a diagram showing an example of the area ratio of wide line segments according to the first embodiment. The example of FIG. 12 shows the area ratio of the wide line segment 42 in the state of FIG. 10(b). In the example of FIG. 12, the ratio of the area of the overlapping portion of the wide line segment 42 to the area of the pixel 36 is indicated as a percentage % as the area ratio. In the example of FIG. 12, 40%, 10%, and 0% are defined in order from the bottom for the left pixel column in the x direction. 50%, 80%, and 60% are defined in order from the bottom for the central pixel row in the x direction. 0%, 5%, and 30% are defined in order from the bottom for the pixel column on the right side in the x direction. In the example of FIG. 12, the area ratio is shown as a percentage, but it goes without saying that it may be defined as a ratio of values between 0 and 1.

In the actual image gradation value calculation step (S127), the actual image gradation value calculation unit 67 calculates each pixel based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size. Calculate the gradation value. Specifically, the actual image gradation value calculation unit 67 calculates a value obtained by multiplying a preset maximum gradation value by the area ratio of the target pixel as the gradation value of the pixel.

13 is a diagram showing an example of image data of a line segment image according to Embodiment 1. FIG. In the example of FIG. 13, image data of gradation values of 256 gradations from 0 to 255 are shown. Therefore, the maximum gradation value M in such a case is 255. Therefore, the actual image tone value calculation unit 67 calculates M×area ratio for each pixel. When the area ratio is defined by a percentage N, the actual image tone value calculator 67 calculates M×N/100 for each pixel. When the area ratio is defined by the ratio N' of values between 0 and 1, the actual image gradation value calculator 67 calculates M×N' for each pixel.

As the actual image gradation value setting step (S128), the actual image gradation value setting unit 68 sets each pixel based on the positional relationship between the created wide line segment 42 and the plurality of pixels 36 forming the image of a predetermined size. Set the gradation value of the pixel 36 . Here, as the positional relationship, the area ratio of the wide line segment 42 included in the target pixel for each pixel is used as described above. Therefore, the gradation value of each pixel is set according to the area ratio of the target pixel. Specifically, the gradation value of each pixel is set to a value obtained by multiplying a preset maximum gradation value M by the area ratio of the target pixel. Therefore, the gradation value calculated in the actual image gradation value calculation step (S127) is set as the gradation value of the pixel. As a result, in the example of FIG. 13, gradation values k of 102, 26, and 0 are defined in order from the bottom for the left pixel row in the x direction. Gradation values of 128, 204, and 153 are defined in order from the bottom for the central pixel row in the x direction. Gradation values of 0, 13, and 77 are defined in order from the bottom for the right pixel row in the x direction.

As a determination step (S129), the determination unit 69 determines whether or not image data has been created for all line segments. If there remains a line segment for which image data has not yet been created, the process returns to the actual image line segment width enlarging step (actual image wide line segment creation step) (S124), and image data is created for all line segments. Each step from the actual image line segment width enlarging step (actual image wide line segment creating step) (S124) to the determination step (S129) is repeated until the actual image line segment width is increased. When image data is created for all line segments, the process proceeds to the comparison step (S140).

Note that the gradation values of the pixels located at the locations where the line segments 40 are joined may be set to the gradation values obtained by adding the gradation values obtained respectively. Note that when the enlarged line segments 42 overlap each other at the joining point, the gradation value corresponding to the area excluding one area of the overlapping area portion (not overlapping and adding) may be calculated and set. The image data of the actual image outline or each line segment for which the gradation value of each pixel is set is output to the comparison processing section 84 . Alternatively, it is output to the storage device 109 . Alternatively, the outline may be displayed on the monitor 117 .

As described above, the gradation value of the pixel through which the line segment 40 passes can be increased, and the gradation value of the adjacent pixel through which the line segment 40 does not pass can be decreased. Therefore, it is possible to form a multi-valued gradient, which is larger than a binary value, in the gradation values of one or more adjacent pixels. As a result, the position of the line segment can be obtained in units of sub-pixels, with the peak position of the gradient as the position through which the line segment passes. Furthermore, since the line segment passes through the peak position of the gradient, it is possible to form an image of a straight line instead of an image of a line that is bent stepwise as in the first comparative example. Regarding the line segment passing through the center of the pixel and extending in the pixel arrangement direction, the gradation value of the pixel through which the line segment 40 passes is 100%, and the gradation value of the adjacent pixel through which the line segment 40 does not pass is 0%. However, in such a case, it becomes clear that it is a line segment passing through the center of the pixel and extending in the pixel arrangement direction.

In the reference contour image creating step (S130), the reference contour image creating unit 70 develops the contour into an image using the reference contour data to create a reference contour image. Specifically, it operates as follows.

In the reference line segment creation step (S132), the reference line segment creation unit 72 divides the target contour line into straight lines of a predetermined length for each contour line in the frame area 30, and determines the start point and end point of the straight line. At least one line segment (actual line segment) is created by obtaining . The content of the reference line segment creation step (S132) may be the same as that of the actual image line segment creation step (S122).

As the reference line segment width enlarging step (reference wide line segment creating step) (S134), the reference wide line segment creating unit 74 creates a line of one or more pixels around the desired line segment in the normal direction of the desired line segment. Create a wide line segment with a width. The contents of the reference line segment width enlarging step (reference wide line segment creating step) (S134) may be the same as the actual image line segment width enlarging step (actual image wide line segment creating step) (S124).

As the reference area ratio calculation step (S136), the reference area ratio calculator 76 calculates the area ratio of the wide line segment 42 included in the target pixel for each of the plurality of pixels 36 forming the image. The content of the reference area ratio calculation step (S136) may be the same as the actual screen area ratio calculation step (S126).

In the reference tone value calculation step (S137), the reference tone value calculation unit 77 calculates the tone of each pixel based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size. Calculate the value. Specifically, the reference tone value calculator 77 calculates a value obtained by multiplying a preset maximum tone value by the area ratio of the target pixel as the tone value of the pixel. The content of the reference tone value calculation step (S137) may be the same as the actual image tone value calculation step (S127).

In the reference tone value setting step (S138), the reference tone value setting unit 78 sets each pixel 36 based on the positional relationship between the created wide line segment 42 and a plurality of pixels 36 forming an image of a predetermined size. Set the gradation value of Here, as the positional relationship, the area ratio of the wide line segment 42 included in the target pixel for each pixel is used as described above. Specifically, the gradation value calculated in the reference gradation value calculation step (S137) is set as the gradation value of the pixel. The content of the reference tone value setting step (S138) may be the same as the actual image tone value setting step (S128)).

As a determination step (S139), the determination unit 79 determines whether or not image data has been created for all line segments. If there remains a line segment for which image data has not yet been created, the process returns to the reference line segment width enlarging step (reference wide line segment creating step) (S134) until image data is created for all line segments. Each step from the reference line segment width enlarging step (reference wide line segment creating step) (S134) to the determination step (S139) is repeated. When image data is created for all line segments, the process proceeds to the comparison step (S140).

As described above, it is possible to obtain the same effect as that of the actual image line segment for the reference line segment.

As a comparison step (S140), the comparison processing unit 84 (comparison unit) compares the actual image contour with the reference contour.

FIG. 14 is a diagram showing an example of the positional relationship between the actual image contour and the reference contour according to the first embodiment. Specifically, the comparison processing unit 84 calculates the distance (positional deviation amount) between the actual image contour line and the reference contour line, as shown in FIG. 14, for each pixel in the pixel row through which the contour line passes. . Then, when the distance (positional deviation amount) exceeds the determination threshold value, it is determined as a defect. The comparison result is output to storage device 109 , monitor 117 or memory 118 .

FIG. 15 is a diagram showing an example of data amounts in the first embodiment and the third comparative example. In FIG. 15A, in Comparative Example 3, the contour line data is defined for each pixel by the distance d from the center of the pixel and the angle θ of the normal direction of the contour line. In this case, since the distance d and the angle θ are each defined by, for example, 8 bits (1 byte) separately from the pixel position data, a data amount of 2 bytes is required for each pixel. For pixels that do not pass through the contour line, the distance d and the angle θ are both defined as NULL, so a 2-byte data amount is required. On the other hand, in Embodiment 1, as shown in FIG. 15B, each pixel is defined by, for example, an 8-bit gradation value k, so that each pixel can have a data amount of 1 byte. Therefore, the data amount of line segment pixels can be reduced.

As described above, according to Embodiment 1, a two-dimensional image of fine line segments can be created. Therefore, when performing contour line inspection, comparison can be made in a highly accurate positional relationship. Therefore, a highly accurate positional deviation amount can be acquired.

In the above description, a series of "-circuits" includes processing circuits, and the processing circuits include electric circuits, computers, processors, circuit boards, quantum circuits, semiconductor devices, and the like. Also, each "-circuit" may use a common processing circuit (the same processing circuit). Alternatively, different processing circuits (separate processing circuits) may be used. A program that causes a processor or the like to be executed may be recorded on a recording medium such as a magnetic disk device or flash memory. For example, the position circuit 107, the comparison circuit 108, the reference contour extraction circuit 112, the stage control circuit 114, the lens control circuit 124, the blanking control circuit 126, and the deflection control circuit 128 are composed of at least one processing circuit described above. can be

The embodiments have been described above with reference to specific examples. However, the invention is not limited to these specific examples. Although the example of FIG. 1 shows the case of forming the multiple primary electron beams 20 by the shaping aperture array substrate 203 from one beam irradiated from the electron gun 201 as one irradiation source, the present invention is limited to this. is not. A mode in which the multiple primary electron beams 20 are formed by irradiating primary electron beams from a plurality of irradiation sources may be employed.

In addition, descriptions of parts that are not directly necessary for the explanation of the present invention, such as the device configuration and control method, are omitted, but the required device configuration and control method can be appropriately selected and used.

In addition, all pattern inspection apparatuses and methods for acquiring the amount of alignment between contour lines that have the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

10 primary electron beam 20 multi primary electron beam 22 hole 29 sub-irradiation area 30 frame area 31 frame image 32 stripe area 33 rectangular area 34 irradiation area 40 line segments 42, 44 wide line segments 50, 52, 56, 57 storage device 54 Frame image creation unit 58 Actual image contour line extraction unit 60 Actual image outline image creation unit 62 Actual image line segment creation unit 64 Actual image wide line segment creation unit 66 Actual image area ratio calculation unit 67 Actual image gradation value calculation unit 68 Actual image gradation value setting unit 69 Judgment unit 70 Reference outline image creation unit 72 Reference line segment creation unit 74 Reference wide line segment creation unit 76 Reference area ratio calculation unit 77 Reference gradation value calculation unit 78 Reference gradation value setting Section 79 Judgment Section 84 Comparison Processing Section 100 Inspection Device 101 Substrate 102 Electron Beam Column 103 Inspection Room 105 Stage 106 Detection Circuit 107 Position Circuit 108 Comparison Circuit 109 Storage Device 110 Control Computer 112 Reference Contour Extraction Circuit 114 Stage Control Circuit 117 Monitor 118 Memory 120 Bus 122 Laser length measurement system 123 Chip pattern memory 124 Lens control circuit 126 Blanking control circuit 128 Deflection control circuit 142 Drive mechanism 144, 146, 148 DAC amplifier 150 Image acquisition mechanism 160 Control system circuit 201 Electron gun 202 Electromagnetic lens 203 Shaping aperture array substrates 205, 206, 207, 224, 226 Electromagnetic lens 208 Main deflector 209 Sub-deflector 212 Collective blanking deflector 213 Limiting aperture substrate 214 Beam separator 216 Mirror 218 Deflector 222 Multi-detector 300 Multi-secondary electrons beam 330 inspection area 332 chip

Claims (5)

A line segment image creation method for creating a two-dimensional image of a desired line segment,
creating a wide line segment having a width of one pixel size or more in the normal direction of the desired line segment centered on the desired line segment;
A gradation value for each pixel is set based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size, and image data in which the gradation value for each pixel is set is output. process and
A line segment image creation method comprising: further comprising the step of calculating the area ratio of the wide line segment included in the target pixel for each pixel as the positional relationship;
2. The line segment image creation method according to claim 1, wherein the gradation value of each pixel is set according to the area ratio of the target pixel. further comprising the step of calculating a value obtained by multiplying a preset maximum gradation value by the area ratio of the target pixel;
3. The line segment image generating method according to claim 2, wherein the gradation value of each pixel is set to a value obtained by multiplying a preset maximum gradation value by the area ratio of the target pixel. The maximum width of the wide line segment is set to a width size that is equal to or greater than one pixel size and that pixels adjacent to pixels overlapping the wide line segment do not include other wide line segments. 3. The line segment image creating method according to claim 2. A line segment image creating device for creating a two-dimensional image of a desired line segment,
a wide line segment creation unit for creating a wide line segment having a width of one pixel size or more in a normal direction of the desired line segment centered on the desired line segment;
A gradation value for each pixel is set based on the positional relationship between the created wide line segment and a plurality of pixels forming an image of a predetermined size, and image data in which the gradation value for each pixel is set is output. a gradation value setting unit;
A line segment image creation device comprising:

Images