Substrate for measuring irradiation position, method for adjusting the irradiation position of laser light, and laser light irradiation position evaluation system

Abstract

This invention provides a measuring substrate that allows for adjustment of the irradiation position of the laser beam used for height position measurement without removing the microscope column. [Configuration] An irradiation position measuring substrate 300 according to one aspect of the present invention is characterized by comprising: a substrate body 302 that can be placed on a stage in the apparatus; a two-dimensional sensor 304 mounted on the substrate body for measuring the intensity distribution of incident laser light; a power supply 308 mounted on the substrate body for driving the two-dimensional sensor; and an interface circuit 309 mounted on the substrate body for outputting information based on the measurement results to an external device.

Description

Technical Field

[0001] The present invention relates to a substrate for measuring an irradiation position, a method for adjusting an irradiation position of a laser beam, and a laser beam irradiation position evaluation system.

Background Art

[0002] Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating patterns in the semiconductor manufacturing process. In recent years, with the high integration of LSIs, the circuit line widths required for semiconductor devices have been continuously miniaturized year by year. Here, electron beam (electron beam) lithography technology inherently has excellent resolution, and electron beams are used to draw on masks for wafer exposure, wafers, etc.

[0003] For example, there is a drawing device using a multi-electron beam. Compared with the case of drawing with a single electron beam, by using a multi-electron beam, many beams can be irradiated at once, so the throughput can be significantly improved. In such a multi-beam type drawing device, for example, an electron beam emitted from an electron gun is passed through a mask having a plurality of holes to form a multi-beam, and each beam is blanking-controlled, and each unshielded beam is reduced by an optical system and deflected by a deflector and irradiated to a desired position on the sample.

[0004] Here, when irradiating a sample with a single electron beam or a multi-electron beam, the height position of the sample surface becomes important. If the height position changes due to unevenness on the sample surface, etc., the irradiation position of the beam will shift. Therefore, in a drawing device, for example, a z-sensor is used to irradiate the sample with a laser beam, measure the position of the reflected light reflected from the sample, and measure the height position at each position on the sample surface.

[0005] To perform such measurements, it is necessary to align the optical axis of the laser beam so that the spot position of the laser beam is, for example, at the height of the sample surface, the center of the electron beam's trajectory. Conventionally, this optical axis adjustment was performed by attaching an optical axis adjustment jig to the lithography device. However, because the optical axis adjustment jig interfered with the electron beam column (electron microscope tube), it was necessary to remove the electron beam column in order to attach the optical axis adjustment jig. Furthermore, since the column had to be reinstalled after removing the optical axis adjustment jig, fine adjustment or readjustment of the optical axis after the column was installed became difficult. Therefore, it was desirable to be able to adjust the optical axis without removing the column. This problem can occur not only in lithography devices but also in the microscope tubes of devices that irradiate light or charged particle beams.

[0006] Here, a measurement substrate is disclosed that, although not used for adjusting the optical axis of a laser beam used for measuring the height position of a sample, has multiple sensors embedded in a body the same shape as a semiconductor wafer to measure temperature or strain, and communicates with an external device (see, for example, Patent Document 1). With the measurement substrate placed inside a lithography apparatus that transfers a chip pattern to a semiconductor wafer, the beam for transferring the pattern is directed onto a photomask, and the heat and strain generated in the measurement substrate during exposure, coating, and development are measured. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2019-504477 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] One aspect of the present invention provides a measuring substrate, method, and system that enable adjustment of the irradiation position of a laser beam for height position measurement without removing the lens barrel. [Means for solving the problem]

[0009] A substrate for measuring the irradiation position according to one aspect of the present invention is A circuit board body that can be placed on a stage inside the device, A two-dimensional sensor mounted on the main board measures the intensity distribution of the incident laser light, The power supply for driving the 2D sensor is mounted on the main board, An interface circuit mounted on the main board outputs information based on measurement results to an external device, It is characterized by having the following features.

[0010] Furthermore, it is preferable to include a control circuit mounted on the substrate itself that receives information on the measured intensity distribution and calculates the centroid position of the laser beam.

[0011] Furthermore, the control circuit calculates the centroid position of the incident light while the irradiation position measurement substrate is placed on the stage. The interface circuit preferably transmits the calculated center of gravity position wirelessly to an external source.

[0012] Furthermore, it is preferable that the outer periphery of the substrate body be formed to have the same shape and size as the sample placed on the stage.

[0013] A method for adjusting the irradiation position of laser light according to one aspect of the present invention is: In a device having a stage on which the sample is placed, a microscope tube with an illumination optical system, and an illumination mechanism that irradiates laser light to measure the height position of the sample surface on the stage, instead of the sample, The main circuit board and A two-dimensional sensor mounted on the main board measures the intensity distribution of the incident laser light, The power supply for driving the 2D sensor is mounted on the main board, An interface circuit mounted on the main board outputs information based on measurement results to an external device, A step of adjusting the irradiation position of the laser beam that irradiates the irradiation position measuring substrate while an irradiation position measuring substrate having the above is placed on it, A process of irradiating a substrate for measuring the irradiation position with laser light and measuring the intensity distribution of the laser light using a two-dimensional sensor, A step of calculating the centroid position of the laser beam using the information on the intensity distribution of the laser beam measured by the two-dimensional sensor, A step of calculating a correction amount for correcting the deviation of the centroid position of the laser beam from a predetermined position using the calculated centroid position, comprising, Repeating the steps of adjusting the irradiation position of the laser beam, measuring the intensity distribution of the laser beam, calculating the centroid position of the laser beam, and calculating the correction amount for correcting the deviation of the centroid position of the laser beam until the deviation amount of the centroid position of the laser beam is within the allowable range, characterized in that.

[0014] The laser beam irradiation position evaluation system according to one aspect of the present invention, A substrate body having a shape that can be placed on a stage in the apparatus, A two-dimensional sensor mounted on the substrate body for measuring the intensity distribution of the incident laser beam, A power supply mounted on the substrate body for driving the two-dimensional sensor, An interface circuit mounted on the substrate body for outputting information based on the measurement result to an external device, An irradiation position measurement substrate having, Connected communicably to the irradiation position measurement substrate, A receiving unit that receives, via the interface circuit, information on the intensity distribution of the light measured by the two-dimensional sensor or information on the centroid position of the laser beam calculated using the information on the intensity distribution, A calculation unit that calculates a correction amount for correcting the deviation of the centroid position of the laser beam from a predetermined position using the received intensity distribution or centroid position information, A determination unit that determines whether the deviation amount of the centroid position of the laser beam is within the allowable range, A computer having, [[ID=​​​​​​​​​​A power source mounted on the substrate body for driving the two-dimensional sensor, An interface circuit mounted on the substrate body for outputting information based on the measurement results to an external device, An irradiation position measurement substrate having: A receiver that is communicably connected to the irradiation position measurement substrate and receives information on the intensity distribution of light measured by the two-dimensional sensor via the interface circuit, A centroid position calculation unit that calculates the centroid position of the laser beam using the received intensity distribution information, A calculation unit that calculates a correction amount for correcting the deviation of the centroid position of the laser beam from a predetermined position using the calculated centroid position, A determination unit that determines whether the deviation amount of the centroid position of the laser beam is within an allowable range, And a computer having: Characterized by comprising.

Advantages of the Invention

[0016] According to one aspect of the present invention, it is possible to adjust the irradiation position of the laser beam for height position measurement without removing the lens barrel (column).

Brief Description of the Drawings

[0017] [Figure 1] It is a conceptual diagram showing the configuration of the drawing device in Embodiment 1. [Figure 2] It is a conceptual diagram showing the configuration of the shaping aperture array substrate in Embodiment 1. [Figure 3] It is a cross-sectional view showing the configuration of the blanking aperture array mechanism in Embodiment 1. [Figure 4] It is a conceptual diagram for explaining an example of the drawing operation in Embodiment 1. [Figure 5] It is a diagram showing an example of the irradiation region of the multi-electron beam and the pixel to be drawn in Embodiment 1. [Figure 6] It is a diagram for explaining an example of the multi-beam drawing operation in Embodiment 1. [Figure 7] ​This figure shows an example of the configuration of the laser beam irradiation position evaluation system in Embodiment 1. [Figure 8] This figure shows an example of a front view of the irradiation position measurement substrate in Embodiment 1. [Figure 9] This block diagram shows an example of the internal configuration of each component of the laser beam irradiation position evaluation system in Embodiment 1. [Figure 10] This figure shows an example of an image of laser light captured by the irradiation position measurement substrate in Embodiment 1. [Figure 11] This figure shows an example of the intensity distribution of a laser beam image captured by the irradiation position measurement substrate in Embodiment 1. [Figure 12] This figure shows an example of the main steps of the laser beam irradiation position adjustment method in Embodiment 1. [Figure 13] This figure shows an example of the configuration of the height position sensor in Embodiment 1. [Figure 14] This figure shows an example of the irradiation positions of two sets of z sensors in Embodiment 1. [Figure 15] This is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. [Figure 16] This is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. [Figure 17] This is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. [Figure 18] This is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. [Figure 19] This figure shows another example of the configuration of the laser beam irradiation position evaluation system in Embodiment 1. [Modes for carrying out the invention]

[0018] In the following embodiments, a charged particle beam lithography apparatus will be described as an example of a charged particle beam irradiation apparatus. However, the charged particle beam irradiation apparatus is not limited to a charged particle beam lithography apparatus. It includes apparatuses that irradiate a sample with a charged particle beam. For example, it may be a charged particle beam inspection apparatus or an exposure apparatus. Furthermore, a multi-charged particle beam will be described as an example of a charged particle beam. However, it is not limited to a multi-charged particle beam. For example, a single-charged particle beam may be used. Furthermore, an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam; it may be a beam using charged particles such as an ion beam. Moreover, it can be applied to other apparatuses without departing from the gist of the invention. For example, it can be applied to inspection apparatuses and exposure apparatuses that irradiate a sample with light.

[0019] Embodiment 1. Figure 1 is a conceptual diagram showing the configuration of a lithography apparatus in Embodiment 1. In Figure 1, the lithography apparatus 100 includes a lithography mechanism 150 and a control system circuit 160. The lithography apparatus 100 is an example of a multi-charged particle beam lithography apparatus and an example of a multi-charged particle beam exposure apparatus. Furthermore, the lithography apparatus 100 is an example of a raster beam lithography apparatus. The lithography mechanism 150 includes an electron tube 102 (electron beam column) and a lithography chamber 103. Inside the electron tube 102 are an electron gun 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a limiting aperture substrate 206, an objective lens 207, a main deflector 208, and a sub-deflector 209. The illumination lens 202, the molded aperture array substrate 203, the blanking aperture array mechanism 204, the reduction lens 205, the limiting aperture substrate 206, the objective lens 207, the main deflector 208, and the sub-deflector 209 are examples of illumination optical systems. Thus, the electron tube 102 (electron beam column) has an illumination optical system.

[0020] An XY stage 105 is placed inside the drawing chamber 103. Samples 101, such as masks, which will be the substrates to be drawn on during drawing (exposure), are placed on the XY stage 105. Samples 101 include exposure masks used when manufacturing semiconductor devices, or semiconductor substrates (silicon wafers) on which semiconductor devices are manufactured. Samples 101 also include mask blanks with resist coated on them but with no drawings yet. A mirror 210 for measuring the position of the XY stage 105 is also placed on the XY stage 105.

[0021] Furthermore, a height position sensor 220 is placed on the drawing chamber 103. As an example of the height position sensor 220, a z-sensor is shown that measures the reflected light from the sample 101 by obliquely incidenting a laser beam onto the sample 101. The height position sensor 220 is not limited to a z-sensor. It may also be a sensor that measures the reflected light from the sample 101 by incidenting a laser beam perpendicularly onto the sample 101.

[0022] The control system circuit 160 includes a control computer 110, memory 112, deflection control circuit 130, digital-to-analog converter (DAC) amplifier units 132 and 134, z-sensor control circuit 135, lens control circuit 136, stage control mechanism 138, stage position measuring instrument 139, and storage devices 140 and 142 such as magnetic disk drives. The control computer 110, memory 112, deflection control circuit 130, z-sensor control circuit 135, lens control circuit 136, stage control mechanism 138, stage position measuring instrument 139, and storage devices 140 and 142 are connected to each other via a bus (not shown). The deflection control circuit 130 is connected to DAC amplifier units 132 and 134 and a blanking aperture array mechanism 204. The sub-deflector 209 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 132. The main deflector 208 is composed of four or more electrodes, and each electrode is controlled by the deflection control circuit 130 via the DAC amplifier 134. The lens group, including the illumination lens 202, the reduction lens 205, and the objective lens 207, is controlled by the lens control circuit 136.

[0023] The position of the XY stage 105 is controlled by the drive of motors on each axis (not shown) controlled by the stage control mechanism 138. The stage position measuring instrument 139 measures the position of the XY stage 105 by receiving reflected light from the mirror 210 using the principle of laser interferometry.

[0024] The z-sensor (height position sensor 220) has a light emitter and a light receiver. The z-sensor (height position sensor 220) is controlled by the z-sensor control circuit 135. The height position sensor 220 is an example of an irradiation mechanism that irradiates laser light to measure the height position of the surface of the sample 101 on the XY stage 105.

[0025] The control computer 110 contains a rasterization processing unit 50, a dose calculation unit 52, an irradiation time calculation unit 54, a data processing unit 70, a drawing control unit 72, and a transfer processing unit 74. Each of these "~ units" has a processing circuit. Such processing circuits include, for example, electrical circuits, computers, processors, circuit boards, quantum circuits, or semiconductor devices. Each of these "~ units" may use a common processing circuit (the same processing circuit) or different processing circuits (separate processing circuits). Information input to and output from the rasterization processing unit 50, dose calculation unit 52, irradiation time calculation unit 54, data processing unit 70, drawing control unit 72, and transfer processing unit 74, as well as information being calculated, is stored in the memory 112 each time.

[0026] The drawing operation of the drawing device 100 is controlled by the drawing control unit 72. Furthermore, the transfer process of the irradiation time data for each shot to the deflection control circuit 130 is controlled by the transfer processing unit 74.

[0027] Furthermore, drawing data (chip data) is input from outside the drawing device 100 and stored in the storage device 140. The chip data defines information about multiple graphic patterns that constitute the chip pattern. Specifically, for each graphic pattern, the coordinates of each vertex are defined in the order in which the graphic is formed. Alternatively, for example, for each graphic pattern, the graphic code, coordinates, and size are defined.

[0028] Here, Figure 1 shows the configuration necessary to explain Embodiment 1. The drawing device 100 may also have other configurations that are normally necessary.

[0029] Figure 2 is a conceptual diagram showing the configuration of a molded aperture array substrate in Embodiment 1. In Figure 2, the molded aperture array substrate 203 has p rows horizontally (x direction) × q rows vertically (y direction) (p,q≧2) holes (openings) 22 formed in a matrix at a predetermined arrangement pitch. In the example of Figure 2, for example, it shows a case where 512 × 512 rows of holes 22 are formed in the vertical and horizontal (x,y directions). The number of holes 22 is not limited to this. For example, 32 × 32 rows of holes 22 may be formed. Each hole 22 is formed as a rectangle of the same dimensions and shape. Alternatively, they may be circles of the same diameter. A portion of the electron beam 200 passes through each of these multiple holes 22, thereby forming a multi-electron beam 20. In other words, the molded aperture array substrate 203 forms and emits a multi-electron beam 20. The molded aperture array substrate 203 is an example of a source of emission of a multi-electron beam 20 or a multi-beam formation mechanism.

[0030] Figure 3 is a cross-sectional view showing the configuration of the blanking aperture array mechanism in Embodiment 1. As shown in Figure 3, the blanking aperture array mechanism 204 has a blanking aperture array substrate 31 made of a semiconductor substrate such as silicon placed on a support base 33. In the membrane region 330 in the center of the blanking aperture array substrate 31, through holes 25 (openings) for the passage of each beam of the multi-electron beam 20 are opened at positions corresponding to each hole 22 of the molded aperture array substrate 203 shown in Figure 2. Then, a set of control electrodes 24 and counter electrodes 26 (blankers: blanking deflectors) are placed at positions opposite each other across the corresponding through holes 25. In addition, a control circuit 41 (logic circuit) that applies a deflection voltage to the control electrode 24 for each through hole 25 is placed inside the blanking aperture array substrate 31 near each through hole 25. The counter electrodes 26 for each beam are connected to ground.

[0031] An amplifier (an example of a switching circuit), not shown in the diagram, is placed inside the control circuit 41. As an example of an amplifier, a CMOS (Complementary MOS) inverter circuit, which acts as a switching circuit, is placed inside. Either an L (low) potential (e.g., ground potential) that is lower than the threshold voltage, or an H (high) potential (e.g., 1.5V) that is higher than the threshold voltage, is applied as a control signal to the input (IN) of the CMOS inverter circuit. In Embodiment 1, when an L potential is applied to the input (IN) of the CMOS inverter circuit, the output (OUT) of the CMOS inverter circuit, which is the output of the control circuit 41, becomes a positive potential (Vdd). The electric field created by the potential difference with the ground potential of the counter electrode 26 deflects the corresponding beam, and the beam is controlled to turn OFF by being shielded by the limiting aperture substrate 206. On the other hand, when a high potential is applied to the input (IN) of the CMOS inverter circuit (active state), the output (OUT) of the CMOS inverter circuit and the control circuit 41 becomes ground potential, eliminating the potential difference with the ground potential of the counter electrode 26. As a result, the corresponding beam is not deflected, and the control is made so that the beam turns ON upon passing through the limiting aperture substrate 206. This deflection is used for blanking control.

[0032] Next, the operation of the imaging mechanism 150 will be described. The electron microscope tube 102 irradiates the sample 101 with a multi-electron beam 20 (charged particle beam). Specifically, it operates as follows.

[0033] The electron beam 200 emitted from the electron gun 201 (emission source) illuminates the entire molded aperture array substrate 203 almost vertically through the illumination lens 202. Multiple rectangular holes 22 (openings) are formed in the molded aperture array substrate 203, and the electron beam 200 illuminates the area containing all of the multiple holes 22. Each portion of the electron beam 200 irradiated at the location of the multiple holes 22 passes through each of the multiple holes 22 in the molded aperture array substrate 203, thereby forming, for example, a rectangular multi-beam (multiple electron beams) 20. These multi-electron beams 20 pass through the corresponding blankers of the blanking aperture array mechanism 204. Each of these blankers individually blanks the passing beam so that the beam remains ON for a set drawing time (irradiation time).

[0034] The multi-electron beam 20, having passed through the blanking aperture array mechanism 204, is reduced by the reduction lens 205 and travels towards the central hole formed in the limiting aperture substrate 206. Here, the electron beam deflected by the blanker of the blanking aperture array mechanism 204 is positioned away from the central hole in the limiting aperture substrate 206 and is shielded by the limiting aperture substrate 206. On the other hand, the electron beam that was not deflected by the blanker of the blanking aperture array mechanism 204 passes through the central hole in the limiting aperture substrate 206, as shown in Figure 1. In this way, the limiting aperture substrate 206 shields each beam that has been deflected by the blanker of the blanking aperture array mechanism 204 to the beam-off state. Then, each beam of one shot is formed by the beams that have passed through the limiting aperture substrate 206 from the time the beam is turned ON until it is turned OFF. The multi-electron beam 20 that has passed through the limiting aperture substrate 206 is focused by the objective lens 207 to form a pattern image with a desired reduction ratio. The main deflector 208 and sub-deflector 209 then deflect the entire multi-electron beam 20 that has passed through the limiting aperture substrate 206 in the same direction, and each beam is directed to its respective irradiation position on the sample 101. Furthermore, for example, when the XY stage 105 is moving continuously, the main deflector 208 performs tracking control so that the irradiation position of the beam follows the movement of the XY stage 105. Ideally, the multi-electron beam 20 that is irradiated at one time will be arranged at a pitch obtained by multiplying the arrangement pitch of the multiple holes 22 in the molded aperture array substrate 203 by the desired reduction ratio described above.

[0035] Figure 4 is a conceptual diagram illustrating an example of the drawing operation in Embodiment 1. As shown in Figure 4, the drawing area 30 (thick line) of the sample 101 is virtually divided into multiple stripe-shaped areas 32 with a predetermined width in the y direction, for example. The example in Figure 4 shows a case where the drawing area 30 of the sample 101 is divided into multiple stripe areas 32 with a width size substantially the same as the size of the designed irradiation area 34 (drawing field) that can be irradiated with a single irradiation of the multi-electron beam 20 in the y direction. The size of the irradiation area 34 of the designed multi-electron beam 20 in the x direction can be defined by the number of beams in the x direction × the inter-beam pitch in the x direction. The size of the rectangular irradiation area 34 in the y direction can be defined by the number of beams in the y direction × the inter-beam pitch in the y direction.

[0036] First, the XY stage 105 is moved to adjust the position of the irradiation area 34 of the multi-electron beam 20 to the left edge of the first stripe area 32, or even further to the left, and the first stripe area 32 is drawn. When drawing the first stripe area 32, the drawing progresses relatively in the x direction by moving the XY stage 105, for example, in the -x direction. The XY stage 105 is moved continuously at a constant speed, for example. After the drawing of the first stripe area 32 is completed, the stage position is moved in the -y direction by the width of the stripe area 32.

[0037] Next, the irradiation area 34 of the multi-electron beam 20 is adjusted to be located at the left edge of the second stripe area 32, or even further to the left, and the drawing of the second stripe area 32 is performed by moving the XY stage 105, for example, in the -x direction, thereby relatively advancing the drawing in the x direction.

[0038] Furthermore, although the above example shows the case where each stripe region 32 is drawn in the same direction, it is not limited to this. For example, for the stripe region 32 to be drawn after the stripe region 32 drawn in the x direction, the XY stage 105 can be moved, for example, in the x direction, so that the drawing is performed relatively in the -x direction. By drawing while alternating directions in this way, the stage movement time can be shortened, and consequently the drawing time can be shortened. In a single shot, the multi-electron beam 20 formed by passing through each hole 22 of the molded aperture array substrate 203 forms up to the same number of shot patterns as each hole 22 at once.

[0039] Furthermore, while the example in Figure 4 shows the case where the stage is moved once for the drawing process of each stripe area, this is not the only option. It is also preferable to perform multiple drawing (multiple-path drawing) by moving the stage multiple times over the same position. In that case, for example, it is preferable to perform multiple drawing while shifting in the y direction by an amount equal to 1 / n of the width of the stripe area. Alternatively, it is also preferable to perform multiple drawing (in-path multiple drawing) in which the same position is drawn multiple times with different beams during a single stage movement.

[0040] Figure 5 shows an example of the irradiation area and drawing target pixels of a multi-electron beam in Embodiment 1. In Figure 5, the stripe area 32 is divided into multiple mesh areas, for example, by the beam size of the multi-electron beam 20. Each of these mesh areas becomes a drawing target pixel 36 (irradiation unit area, irradiation position). The size of the drawing target pixel 36 is not limited to the beam size and may be composed of any size regardless of the beam size. For example, it may be composed of a size of 1 / n (where n is an integer of 1 or more) of the beam size. In the example of Figure 5, the drawing area of ​​the sample 101 is shown as being divided into multiple stripe areas 32 in the y direction, for example, with a width size that is substantially the same as the size of the irradiation area 34 (drawing field) that can be irradiated with one irradiation of the multi-electron beam 20. The size of the rectangular irradiation area 34 in the x direction can be defined by the number of beams in the x direction × the inter-beam pitch in the x direction. The size of the rectangular irradiation area 34 in the y direction can be defined by the number of beams in the y direction × the inter-beam pitch in the y direction. In the example in Figure 5, for example, a 512×512-row multibeam is shown as an 8×8-row multibeam. Within the irradiation area 34, multiple pixels 28 (beam drawing positions) that can be irradiated with a single shot of the multi-electron beam 20 are shown. The pitch between adjacent pixels 28 becomes the inter-beam pitch of the multibeam. A rectangular region enclosed by the size of the inter-beam pitch in the x,y directions constitutes one sub-irradiation area 29 (pitch cell region). In the example in Figure 5, each sub-irradiation area 29 is shown as being composed of, for example, 4×4 pixels.

[0041] Figure 6 is a diagram illustrating an example of multi-beam lithography operation in Embodiment 1. The example in Figure 6 shows a case where each sub-irradiation area 29 is lithographed with four different beams. Furthermore, the example in Figure 6 shows a lithography operation in which the XY stage 105 moves continuously at a speed of a distance L equivalent to 8 beam pitches while lithographing 1 / 4 (1 out of the number of beams used for irradiation) of each sub-irradiation area 29. In the lithography operation shown in the example in Figure 6, for example, while the XY stage 105 moves a distance L equivalent to 8 beam pitches, the sub-deflector 209 sequentially shifts the irradiation position (pixel 36), and four shots of the multi-beam 20 are performed in a shot cycle T to lithograph (expose) four different pixels within the same sub-irradiation area 29. While lithographing (exposing) these four pixels, the main deflector 208 deflects the entire multi-beam 20 collectively so that the irradiation area 34 does not shift relative to the sample 101 due to the movement of the XY stage 105, thereby causing the irradiation area 34 to follow the movement of the XY stage 105. In other words, tracking control is performed. When one tracking cycle is completed, the tracking is reset and returns to the previous tracking start position. Since the drawing of the first pixel row from the right in each sub-irradiation area 29 has been completed, after the tracking reset, in the next tracking cycle, the sub-deflector 209 first deflects the beam to adjust (shift) its drawing position so that it can draw, for example, the second pixel row from the right in each sub-irradiation area 29, which has not yet been drawn. By repeating this operation while drawing the stripe area 32, the position of the irradiation area 34 of the multi-beam 20 moves sequentially as shown in the irradiation areas 34a, 34b, 34c, ... 34o in the lower part of Figure 4, and drawing is performed.

[0042] As mentioned above, when irradiating the sample 101 with the multi-electron beam 20, the height position of the sample 101 surface is important. If the height position changes due to irregularities on the surface of the sample 101, a shift in the beam irradiation position will occur. Therefore, the lithography device 100 uses, for example, a z-sensor to irradiate the sample 101 with laser light and measure the position of the reflected light reflected from the sample 101 to measure the height position at each point on the surface of the sample 101.

[0043] To perform such measurements, it is necessary to align the optical axis of the laser beam so that the spot position of the laser beam on the surface of the sample 101 is, for example, the center of the electron beam's trajectory at the height of the surface of the sample 101. Conventionally, this optical axis adjustment was performed by attaching an optical axis adjustment jig to the lithography device 100. However, because the optical axis adjustment jig interfered with the electron beam column 102, it was necessary to remove the electron beam column 102 in order to attach the optical axis adjustment jig. Furthermore, since the electron beam column 102 had to be reinstalled after the optical axis adjustment jig was removed, fine adjustment and readjustment of the optical axis became difficult after the electron beam column 102 was installed. Therefore, it was desirable to be able to perform optical axis adjustment without removing the electron beam column 102. Therefore, in Embodiment 1, instead of the sample 101, an irradiation position measurement substrate is placed on the XY stage 105, and the optical axis of the laser beam is adjusted without using an optical axis adjustment jig and without removing the electron microscope tube 102. A detailed explanation follows below.

[0044] Figure 7 shows an example of the configuration of the laser beam irradiation position evaluation system in Embodiment 1. In Figure 7, the laser beam irradiation position evaluation system 500 includes an irradiation position measurement substrate 300 and a computer 400. In the example in Figure 7, an example of a top view of the irradiation position measurement substrate 300 is shown. Wireless or wired communication is performed between the irradiation position measurement substrate 300 and the computer 400. In the example in Figure 7, wireless communication is shown. During measurement, the irradiation position measurement substrate 300 is placed on the XY stage 105 in the drawing device 100 instead of the sample 101. The computer 400 is placed outside the drawing device 100 as an external device. In the example shown in Figure 7, the computer 400 is located outside the drawing device, but this is not the only option. For example, the control system circuit 160 may include the computer 400. Alternatively, the functions of the computer 400 may be placed within the control computer 110.

[0045] Figure 8 shows an example of a front view of the irradiation position measurement substrate in Embodiment 1. In Figures 7 and 8, the irradiation position measurement substrate 300 comprises a substrate body 302, a two-dimensional sensor 304, a control circuit 306, a power supply 308 such as a battery or power supply (receiving) circuit, and an interface (I / F) circuit 309. The two-dimensional sensor 304, control circuit 306, power supply 308, and interface (I / F) circuit 309 are mounted on the substrate body 302.

[0046] Furthermore, it is desirable, but not limited to, that the 2D sensor 304, control circuit 306, power supply 308, and I / F circuit 309 be located at the same height as the surface height of the main board 302 or inside the main board 302. For example, at least a portion of at least one of the 2D sensor 304, control circuit 306, power supply 308, and I / F circuit 309 may protrude outward from the surface height of the main board 302. Figure 8 shows an example where a portion of the 2D sensor 304 protrudes outward from the surface height of the main board 302.

[0047] The substrate body 302 is formed so that it can be placed on a stage within the apparatus. For example, it is formed in a shape that can be placed on the XY stage 105 in the apparatus that is irradiated with an electron beam, in this case the writing apparatus 100, in place of the sample 101. For example, the outer periphery of the substrate body 302 is formed to be the same shape and size as the sample 101. However, it is not limited to this. It may be formed to be smaller in size than the sample 101 as long as it can be placed on the XY stage 105. If it is formed to be smaller in size, it is acceptable to place the substrate body 302 on the XY stage 105 using a jig or the like (not shown).

[0048] The two-dimensional sensor 304 measures the intensity distribution of laser light incident from the height position sensor 220 (e.g., z sensor). A photodiode array sensor is preferably used as the two-dimensional sensor 304. A CMOS (Complementary Metal Oxide Semiconductor) sensor is preferably used as the photodiode array sensor. Other sensors, such as a four-segment sensor, may also be used as the two-dimensional sensor 304. The detection surface of the two-dimensional sensor 304 is formed to a size capable of detecting the entire spot of the received laser light. Furthermore, the examples in Figures 7 and 8 show the case where the two-dimensional sensor 304 is positioned at the center of the irradiation position measurement substrate 300.

[0049] The control circuit 306 receives information on the measured intensity distribution of the laser beam and calculates the centroid position of the laser beam. Note that while Figure 7 shows an example where the function for calculating the centroid position of the laser beam is located within the irradiation position measurement substrate 300, this is not the only option. For example, the function could be located within the computer 400.

[0050] Power supply 308 drives the 2D sensor 302. Power supply 308 also drives the control circuit 306. Power supply 308 may also drive the I / F circuit 309 as needed.

[0051] The I / F circuit 309 outputs information based on the measurement results to the computer 400 (external device). This information based on the measurement results includes data on the centroid position or intensity distribution of the laser beam irradiated onto the 2D sensor 304.

[0052] Figure 9 is a block diagram showing an example of the internal configuration of each component of the laser beam irradiation position evaluation system in Embodiment 1. In Figure 9, the control circuit 306 contains a memory 75, a storage device 76 such as a magnetic disk drive, SSD (Solid State Drive), or microSD, a sensor circuit 71, a centroid calculation circuit 73, and a control management circuit 78. The centroid calculation circuit 73 and the control management circuit 78 have processing circuits. Such processing circuits include, for example, electrical circuits, computers, processors, circuit boards, quantum circuits, or semiconductor devices. The centroid calculation circuit 73 and the control management circuit 78 may use a common processing circuit (the same processing circuit) or may use different processing circuits (separate processing circuits). Information input to and output from the centroid calculation circuit 73 and the control management circuit 78, as well as information being calculated, are stored in the memory 75 each time.

[0053] The computer 400 includes a memory 68, a storage device 69 such as a magnetic disk drive, an interface (I / F) circuit 60, a communication control unit 62, an irradiation position adjustment unit 64, a correction amount calculation unit 66, and a determination unit 67. Each of these "~units," such as the communication control unit 62, the irradiation position adjustment unit 64, the correction amount calculation unit 66, and the determination unit 67, has a processing circuit. Such a processing circuit includes, for example, an electrical circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device. The communication control unit 62, the irradiation position adjustment unit 64, the correction amount calculation unit 66, and the determination unit 67 may use a common processing circuit (the same processing circuit) or they may use different processing circuits (separate processing circuits). Information input to and output from the communication control unit 62, the irradiation position adjustment unit 64, the correction amount calculation unit 66, and the determination unit 67, as well as information being calculated, is stored in the memory 68 each time.

[0054] Figure 10 shows an example of an image of laser light captured by the irradiation position measurement substrate in Embodiment 1. Figure 11 shows an example of the intensity distribution of a laser beam image captured by the irradiation position measurement substrate in Embodiment 1. Figure 10 shows an example of an image captured by the 2D sensor 304 when the irradiation position measurement substrate 300 is continuously moved in the x direction and laser light from the z sensor is obliquely incident on the irradiation position measurement substrate 300. In the example of Figure 10, images of the laser light are captured from the state where x=12mm has been moved to the state where x=16mm has been moved. It can be seen that the distance between the peak of the intensity distribution of the laser light image captured at x=12mm and the peak of the intensity distribution of the laser light image captured at x=14mm is 2mm, as shown in Figure 11. Thus, it can be seen that the distance between images captured by the irradiation position measurement substrate 300 in Embodiment 1 matches the stage movement distance. Therefore, it can be seen that the irradiation position (optical axis adjustment) of the laser light from the light emitter of the height position sensor 220 can be adjusted using the irradiation position measurement substrate 300.

[0055] Figure 12 shows an example of the main steps of the laser beam irradiation position adjustment method in Embodiment 1. In Figure 12, the laser beam irradiation position adjustment method in Embodiment 1 performs a series of steps: wireless communication connection step (S102), sensor (camera) communication connection step (S104), initial value setting step (S106), irradiation position adjustment step (S108), intensity distribution (image) acquisition step (S110), centroid calculation step (S112), correction amount calculation step (S114), determination step (S116), sensor (camera) communication connection disconnection step (S118), and wireless communication connection disconnection step (S120).

[0056] First, instead of the sample 101, the irradiation position measurement substrate 300 is transported to the drawing room 103 and placed on the XY stage 105. The irradiation position measurement substrate 300 is positioned so that the height of the detection surface of the 2D sensor 304 aligns with the design height of the sample 101 surface. The XY stage 105 is then moved so that the detection surface of the 2D sensor 304 aligns with the trajectory center axis of the multi-electron beam 20.

[0057] Furthermore, the computer 400 is connected to the control computer 110 of the drawing device 100 via a bus (not shown) in a communication manner.

[0058] Figure 13 shows an example of the configuration of a height position sensor in Embodiment 1. In the example in Figure 13, a case is shown where an optical lever type z sensor is used as the height position sensor 220. In the example in Figure 13, two sets of optical lever type height position sensors 220 and 230 are used, and the optical system is arranged so that two beams travel in opposite directions along the same optical path, and the height displacement of the same measurement point is measured with each set. The first set of height position sensors 220 has a light source 80, an XY stage 81, a mirror 82, a lens 83, a half mirror 84, a lens 85, a mirror 86, a lens 87, and a sensor 88. The second set of height position sensors 230 has a light source 90, an XY stage 91, a mirror 92, a lens 93, a half mirror 94, a lens 95, a mirror 96, a lens 97, and a sensor 98. The half-mirror 84, lens 85, mirror 86, half-mirror 94, lens 95, and mirror 96 form a common optical system for the first set of height position sensors 220 and the second set of height position sensors 230.

[0059] For light sources 80 and 90, it is preferable to use, for example, LEDs or optical fibers. Light source 80 is positioned on the XY stage 81 and is movable in the x and y directions. Light source 90 is positioned on the XY stage 91 and is movable in the x and y directions. In other words, the spot position on the irradiation position measuring substrate 300 for laser light emitted from light source 80 can be adjusted in the x and y directions. Similarly, the spot position on the irradiation position measuring substrate 300 for laser light emitted from light source 90 can be adjusted in the x and y directions. The positions of the XY stages 81 and 91 are controlled by the z-sensor control circuit 135. Alternatively, they may be adjustable manually. The z-sensor control circuit 135 is controlled by the irradiation position adjustment unit 64 of the computer 400.

[0060] It is preferable to use PSD (Position Sensitive Detector) sensors (optical position sensors) as sensors 88 and 98. When used with the drawing device 100, if the height position of the surface of the sample 101 changes, the position of the reflected light received by sensors 88 and 98 changes, so the displacement of the height position of the sample 101 can be measured.

[0061] The two sets of height position sensors 220 and 230 irradiate the same position on the irradiation position measurement substrate 300 from two directions, from the x-direction and the -x-direction, and detect the reflected light from each direction.

[0062] Laser light 1 emitted from light source 80 in the -x direction is reflected in the -z direction by mirror 82 and incident on mirror 86 via lens 83, half mirror 84, and lens 85. The laser light 1, reflected by mirror 86, is obliquely incident on the irradiation position measurement substrate 300. For example, it is obliquely incident from a direction that is parallel to the -x direction and perpendicular to the y direction when viewed from above (z direction), and at an angle of about 7° in the +z direction from the surface of the irradiation position measurement substrate 300. The reflected light 1 reflected from the surface of the irradiation position measurement substrate 300 by the oblique incidence of laser light 1 is reflected in the +z direction by mirror 96, passes through lens 95, is reflected in the -x direction by half mirror 94, and incident on sensor 88 via lens 87. The information detected by sensor 88 is output to z sensor control circuit 135. The z sensor control circuit 135 can measure the displacement of the height position of the surface of sample 101 from the amount of change in the centroid position of the reflected light 1 incident on sensor 88.

[0063] Meanwhile, the laser light 2 emitted from the light source 90 in the +x direction is reflected in the -z direction by the mirror 92 and incident on the mirror 96 via the lens 93, half mirror 94, and lens 95. The laser light 2 is reflected by the mirror 96 and obliquely incident on the irradiation position measurement substrate 300. For example, it is obliquely incident from a direction that is parallel to the +x direction and perpendicular to the y direction when viewed from above (z direction), and at an angle of about 7° in the +z direction from the surface of the irradiation position measurement substrate 300. The reflected light 2 reflected from the surface of the irradiation position measurement substrate 300 by the oblique incidence of the laser light 2 is reflected in the +z direction by the mirror 86, passes through the lens 85, is reflected in the +x direction by the half mirror 84, and incident on the sensor 98 via the lens 97. The information detected by the sensor 98 is output to the z sensor control circuit 135. The z sensor control circuit 135 can measure the displacement of the height position of the surface of the sample 101 from the amount of change in the centroid position of the reflected light 1 incident on the sensor 98.

[0064] Figure 14 shows an example of the irradiation positions of two sets of z-sensors in Embodiment 1. In the example in Figure 14, the spot image 12 and its centroid position 13 of laser beam 1 irradiated in the -x direction are shown. Similarly, the spot image 14 and its centroid position 15 of laser beam 2 irradiated in the +x direction are shown. By measuring the same position with two laser beams 1 and 2 from opposite directions, the change in height position due to the unevenness of the sample 101 can be measured with high precision. To achieve this, it is necessary to adjust the optical axes so that laser beams 1 and 2 irradiate the same position. Specifically, the optical axes are adjusted so that the centroid positions 13 and 15 are aligned. For example, the spot positions (irradiation positions) of laser beams 1 and 2 are aligned to a predetermined position. For example, the spot positions (irradiation positions) of laser beams 1 and 2 are aligned to the intersection position of the orbital central axis 21 of the multi-electron beam 20 and the surface of the sample 101. More specifically, for example, the centroid positions 13 and 15 are aligned to the intersection position of the orbital central axis 21 of the multi-electron beam 20 and the surface of the sample 101.

[0065] However, this is not the only option. The height position can be measured using only one set of height position sensors 220. In this case, the spot position (irradiation position) of the laser beam 1 is adjusted to a predetermined position. For example, the spot position (irradiation position) of the laser beam 1 is adjusted to the intersection point between the orbital central axis 21 of the multi-electron beam 20 and the surface of the sample 101. Specifically, the centroid position 13 is adjusted to the intersection point between the orbital central axis 21 of the multi-electron beam 20 and the surface of the sample 101. The adjustment of such irradiation position will be explained in detail below.

[0066] As part of the wireless communication connection process (S102), wireless communication is established between the computer 400 and the irradiation position measurement board 300. This will be explained in detail. First, under the control of the communication control unit 62 in the computer 400, the I / F circuit 60 sends a command to the irradiation position measurement board 300 to establish wireless communication. The I / F circuit 309 in the irradiation position measurement board 300 receives the command from the computer 400 and establishes wireless communication between the computer 400 and the irradiation position measurement board 300.

[0067] As part of the sensor (camera) communication connection process (S104), under the control of the communication control unit 62, the I / F circuit 60 sends a command to the irradiation position measurement board 300 to connect communication with the 2D sensor 304. The I / F circuit 309 in the irradiation position measurement board 300 receives a command from the computer 400 and outputs it to the control management circuit 78. The control management circuit 78 turns on the 2D sensor 304 and connects communication between the 2D sensor 304 and the computer 400.

[0068] As an initial value setting step (S106), the initial value of the correction amount for the irradiation position of the laser beam from the light source 80 (90) of the height position sensor 220 (230) on the substrate 300 for measuring the irradiation position is set. The initial value of the correction amount is set to zero, for example.

[0069] As part of the irradiation position adjustment process (S108), with the irradiation position measurement substrate 300 placed on the XY stage 105 instead of the sample 101, the irradiation position of the laser beam irradiated onto the irradiation position measurement substrate 300 is adjusted. Specifically, it operates as follows: The irradiation position adjustment unit 64 controls the z-sensor control circuit 135 to correct the irradiation position of the laser beam 1 by a calculated or set correction amount. The z-sensor control circuit 135 moves the position of the XY stage 81 to correct the irradiation position of the laser beam 1 by the calculated correction amount. Initially, the position of the XY stage 81 is moved to a position that matches the initial value of the correction amount.

[0070] In the intensity distribution (image) acquisition process (S110), the height position sensor 220 irradiates the irradiation position measurement substrate 300 with laser light 1 and measures the intensity distribution of the laser light using the two-dimensional sensor 304. Specifically, the two-dimensional sensor 304 captures an image of the laser light 1. The analog data (intensity distribution data) of the captured image of the laser light 1 is converted into digital data by the sensor circuit 71, amplified, and then output to the storage device 76 for storage.

[0071] When using two sets of height position sensors 220 and 230, the height position sensor 230 then irradiates the irradiation position measurement substrate 300 with laser light 2, and measures the intensity distribution of the laser light using the two-dimensional sensor 304. Specifically, the two-dimensional sensor 304 captures an image of the laser light 2. The analog data (intensity distribution data) of the captured image of the laser light 2 is converted into digital data by the sensor circuit 71, amplified, and then output to the storage device 76 for storage.

[0072] In the centroid calculation process (S112), the control circuit 306 calculates the centroid position of the laser beam using information on the intensity distribution of the laser beam measured by the two-dimensional sensor 304. In other words, the control circuit 306 calculates the centroid position of the incident light while the irradiation position measurement substrate 300 is placed on the XY stage 105. Specifically, it operates as follows: The centroid calculation circuit 73 reads image data (intensity distribution data) of the laser beam 1 from the storage device 76 and calculates the centroid position of the laser beam 1. The calculated information on the centroid position of the laser beam 1 is stored in the storage device 76.

[0073] Furthermore, it is acceptable to perform data processing such as noise reduction and / or binarization of image data before calculating the centroid position using functions not shown in the diagram of the centroid calculation circuit 73 or the control circuit 306.

[0074] When using two sets of height position sensors 220 and 230, the center of gravity calculation circuit 73 then reads image data (intensity distribution data) of the laser beam 2 from the storage device 76 and calculates the center of gravity of the laser beam 2. The calculated information of the center of gravity of the laser beam 2 is stored in the storage device 76.

[0075] Under the control of the control management circuit 78, the I / F circuit 309 wirelessly transmits the calculated center of gravity position to an external device using wireless network communication. Specifically, the I / F circuit 309 wirelessly transmits the calculated center of gravity position to the computer 400.

[0076] Within the computer 400, the I / F circuit 60 receives information on the center of gravity from the irradiation position measurement substrate 300 and stores it in the memory device 69.

[0077] As a correction amount calculation step (S114), the correction amount calculation unit 66 calculates a correction amount to correct the deviation of the center of gravity of the laser beam 1 from a predetermined position using the calculated center of gravity position. For example, when a multi-electron beam 20 (charged particle beam) is irradiated onto the sample 101, the unit calculates a correction amount to correct the deviation of the center of gravity of the laser beam 1 from the trajectory center position of the multi-electron beam 20 at the surface height position of the sample 101.

[0078] When using two sets of height position sensors 220 and 230, the correction amount calculation unit 66 then uses the calculated centroid position to calculate a correction amount to correct for the deviation of the centroid position of laser beam 2 from the same predetermined position as laser beam 1.

[0079] As a determination step (S116), the determination unit 67 determines whether the amount of deviation of the center of gravity of the laser beam 1 is within an acceptable range. If the determination result shows that the amount of deviation of the center of gravity of the laser beam 1 is within an acceptable range, the process proceeds to the sensor (camera) communication connection disconnection step (S118) for the laser beam 1. If the amount of deviation of the center of gravity of the laser beam 1 is not within an acceptable range, the process returns to the irradiation position adjustment step (S108), and the irradiation position adjustment step (S108), which adjusts the irradiation position of the laser beam, the intensity distribution (image) acquisition step (S110), which measures the intensity distribution of the laser beam, the center of gravity calculation step (S112), which calculates the center of gravity of the laser beam, and the correction amount calculation step (S114), which calculates a correction amount to correct the deviation of the center of gravity of the laser beam, are repeated until the amount of deviation of the center of gravity of the laser beam is within an acceptable range.

[0080] When using two sets of height position sensors 220 and 230, the determination unit 67 then determines whether the amount of deviation of the center of gravity of the laser beam 2 is within an acceptable range. If the determination result shows that the amount of deviation of the center of gravity of the laser beam 2 is within an acceptable range, the process proceeds to the sensor (camera) communication connection disconnection step (S118) for the laser beam 2. If the amount of deviation of the center of gravity of the laser beam 2 is not within an acceptable range, the process returns to the irradiation position adjustment step (S108), and the irradiation position adjustment step (S108), which adjusts the irradiation position of the laser beam, the intensity distribution (image) acquisition step (S110), which measures the intensity distribution of the laser beam, the center of gravity calculation step (S112), which calculates the center of gravity of the laser beam, and the correction amount calculation step (S114), which calculates a correction amount to correct the deviation of the center of gravity of the laser beam, are repeated for the laser beam 2 until the amount of deviation of the center of gravity of the laser beam 2 is within an acceptable range.

[0081] The example above shows the case where the optical axis adjustment of laser beam 1 and laser beam 2 are performed together, but this is not the only option. For example, the adjustment process may be performed separately, such as adjusting the optical axis of laser beam 2 after the adjustment of laser beam 1 has been completed.

[0082] As a sensor (camera) communication connection disconnection process (S118), under the control of the communication control unit 62, the I / F circuit 60 sends a command to the irradiation position measurement board 300 to disconnect the communication connection with the 2D sensor 304. The I / F circuit 309 in the irradiation position measurement board 300 receives the command from the computer 400 and outputs it to the control management circuit 78. The control management circuit 78 turns off the 2D sensor 304 and disconnects the communication connection between the 2D sensor 304 and the computer 400. This reduces the consumption of, for example, the battery used as the power supply 308.

[0083] As a wireless communication connection disconnection step (S120), the wireless communication connection between the computer 400 and the irradiation position measurement board 300 is disconnected. Specifically, it operates as follows: Under the control of the communication control unit 62 in the computer 400, the I / F circuit 60 sends a command to the irradiation position measurement board 300 to disconnect the wireless communication connection. The I / F circuit 309 in the irradiation position measurement board 300 receives the command from the computer 400 and disconnects the wireless communication connection between the computer 400 and the irradiation position measurement board 300.

[0084] In the example described above, the calculation of the center of gravity is performed within the irradiation position measurement substrate 300, but this is not the only option. For example, under the control of the control management circuit 78, the I / F circuit 309 wirelessly transmits information (image data) of the light intensity distribution measured by the 2D sensor 304 to the computer 400. The computer 400 can then calculate the center of gravity of the laser beam using the intensity distribution information. In this case, the function of the center of gravity calculation circuit 73 is located within the computer 400.

[0085] In this manner, the I / F circuit 60 (receiving unit) receives information on the light intensity distribution measured by the 2D sensor 304, or information on the centroid position of the laser beam calculated using the intensity distribution information, via the I / F circuit 309. The correction amount calculation unit 66 then uses the received intensity distribution or centroid position to calculate a correction amount to correct the deviation of the centroid position of the laser beam from a predetermined position.

[0086] When the optical axis adjustment jig is attached to the drawing device, it was difficult to accurately measure the irradiation position of the laser beam from the height position sensor 220. However, by using the irradiation position measurement substrate 300, the stage position measuring instrument 139 can measure the position with high precision, thus enabling high-precision measurement of the irradiation position of the laser beam from the height position sensor 220. Furthermore, when the optical axis adjustment jig is attached to the drawing device, the image quality deteriorates if, for example, the image reflected from a diffuse reflecting surface is used. However, by using the irradiation position measurement substrate 300, the image of the laser beam can be directly captured, resulting in a high-precision image. Therefore, it is easier to quantify the data with higher precision than when the optical axis adjustment jig is attached to the drawing device. As a result, high-precision irradiation position adjustment is possible. In addition, vibration is a problem when the optical axis adjustment jig is attached to the drawing device, but by using the irradiation position measurement substrate 300, vibration can be limited, for example, on the vibration isolation table on which the drawing device 100 is placed.

[0087] Figure 15 is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. In the example in Figure 7, the two-dimensional sensor 304 is shown to be located in the center of the irradiation position measurement substrate 300, but this is not the only example. In the example in Figure 15, the two-dimensional sensor 304 is shown to be located on the outer periphery of the irradiation position measurement substrate 300. Accordingly, the positions of the control circuit 306, power supply 308, and I / F circuit 309 are also adjusted.

[0088] Figure 16 is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. In the example in Figure 16, the two-dimensional sensor 304 is positioned at one of the four corners of the irradiation position measurement substrate 300. Accordingly, the positions of the control circuit 306, power supply 308, and I / F circuit 309 are also adjusted.

[0089] If the 2D sensor 304 protrudes above the surface height of the substrate body 302, it may interfere with other components at the bottom of the electron beam column 102 or with components of the transport system. For example, if the 2D sensor 304 is placed in the center of the substrate body 302, it may interfere with other components when transported onto the XY stage 105. Alternatively, if the detection surface of the 2D sensor 304 is aligned with the trajectory center axis of the multi-electron beam 20 while it is placed on the XY stage 105, it may interfere with other components. To avoid these issues, it is preferable to change the placement position of the 2D sensor 304.

[0090] Figure 17 is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. While Figure 7 shows a case where one 2D sensor 304 is arranged, this is not the only example. Arranging multiple 2D sensors 304 is also preferable. Figure 17, for example, shows a case where a total of five 2D sensors 304 are arranged at the four corners and the center of the irradiation position measurement substrate 300.

[0091] Figure 18 is a top view showing another example of the irradiation position measurement substrate in Embodiment 1. In the example in Figure 18, for example, a total of nine 2D sensors 304 are arranged in a 3x3 array on the irradiation position measurement substrate 300.

[0092] By arranging multiple 2D sensors 304, it is possible to measure height displacement that depends on the position of the XY stage 105. For example, if the position of a 2D sensor 304 in another position shifts when the irradiation position of the laser beam from the height position sensor 220 is adjusted using the central 2D sensor 304, it indicates that there is a height displacement that depends on the position of the XY stage 105.

[0093] Furthermore, by placing a fluorescent plate on the sensor surface of the irradiation position measurement substrate 300, the beam can be converted to visible light, enabling beam position measurement. Alternatively, the irradiation position measurement substrate 300 may be equipped with only the 2D sensor 304 and controlled externally.

[0094] Figure 19 shows another example of the configuration of the laser beam irradiation position evaluation system in Embodiment 1. In the example of Figure 7 described above, wireless communication was shown between the irradiation position measurement board 300 and the computer 400, but as shown in Figure 19, wired communication may be performed between the I / F circuit 309 of the irradiation position measurement board 300 and the I / F circuit 60 of the computer 400. Also, in the example of Figure 19, a power receiving circuit is shown as the power supply 308 that drives the 2D sensor 304. In this case, power is supplied from the computer 400 via a wire. Also, in the example of Figure 19, the control circuit 306 is not installed, and information on the intensity distribution of the laser beam measured by the 2D sensor 304 is output from the irradiation position measurement board 300 to the computer 400 via the I / F circuit 309. The calculation of the center of gravity position, etc., will be performed by the computer 400.

[0095] As described above, the irradiation position (optical axis) of the height position sensor 220 (230) on the sample surface is adjusted. After adjustment, the irradiation position measurement substrate 300 is removed from the drawing chamber 103. Then, the sample 101 to be drawn is transported into the drawing chamber 103 and placed on the XY stage 105. Next, the drawing process will be described.

[0096] In the height position measurement process, the height position sensor 220 measures the height position of each point on the surface of the sample 101. Specifically, for each stripe region 32, the sample 101 is scanned with the laser beam of the height position sensor 220. The reflected light is then measured by the sensor 88, and the height position of the sample surface in that stripe region 32 is measured by measuring the displacement of the centroid of the reflected light. The measured height position data is stored in the storage device 142. It is advisable to measure the height position of all stripe regions 32 in advance.

[0097] As part of the rasterization process, the rasterization processing unit 50 reads chip pattern data (drawing data) from the storage device 140 and performs rasterization. Specifically, for each pixel 36, it calculates the pattern density ρ(x) (pattern area density) of the graphic pattern placed within the pixel. For example, it is preferable to perform rasterization for each stripe region 32.

[0098] As part of the dose calculation process, the dose calculation unit 52 calculates the dose amount (irradiation amount) to be incident on each pixel 36. Specifically, it operates as follows: The dose amount D can be calculated, for example, by multiplying a preset reference irradiation amount Dbase by the proximity effect correction irradiation amount Dp and the pattern area density ρ. The proximity effect correction irradiation amount Dp is given as a relative value normalized with the reference irradiation amount Dbase set to 1. Thus, it is preferable to determine the dose amount D in proportion to the area density of the pattern calculated for each pixel 36. For the proximity effect correction irradiation amount Dp, the drawing area (here, for example, the stripe area 32) is virtually divided into multiple proximity mesh areas (mesh areas for proximity effect correction calculation) of a predetermined size. The size of the proximity mesh area is preferably set to about 1 / 10 of the area of ​​influence of the proximity effect, for example, about 1 μm. Then, the drawing data is read from the storage device 140, and for each proximity mesh area, the pattern density ρ' (pattern area density) of the pattern placed within that proximity mesh area is calculated.

[0099] Next, for each adjacent mesh region, a proximity effect correction dose Dp is calculated to correct for the proximity effect. Here, the size of the mesh region for calculating the proximity effect correction dose Dp does not need to be the same as the size of the mesh region for calculating the pattern area density ρ. Also, the correction model and calculation method for the proximity effect correction dose Dp can be the same as the method used in conventional single-beam lithography. A dose map is created in which dose amount data for every 36 pixels is defined.

[0100] When performing multiplex drawing, a dose map is created for each multiplex drawing process. In other words, a dose map is created for each stripe layer. The created dose maps are stored in the memory device 142.

[0101] As part of the irradiation time calculation process, the irradiation time calculation unit 54 calculates the irradiation time t of the electron beam to inject the calculated dose amount D into each pixel 36. The irradiation time t can be calculated by dividing the dose amount D by the current density J. This creates an irradiation time map in which irradiation time data for each pixel 36 is defined. The created irradiation time map is stored in the storage device 142.

[0102] As part of the data processing process, the data processing unit 70 processes the irradiation time data so that it is sorted in shot order. The irradiation time data is then stored in the storage device 142.

[0103] Then, the transfer processing unit 74 transfers the irradiation time data to the deflection control circuit 130 in the order of the shots.

[0104] In the drawing process, under the control of the drawing control unit 72, the drawing mechanism 150 draws a pattern on the sample 101 using the multi-electron beam 20. At this time, the focal height position of the multi-electron beam 20 is dynamically corrected in accordance with changes in height. The correction of the focal height position of the multi-electron beam 20 is performed using an electrostatic lens (not shown), or it may be done with the objective lens 207.

[0105] As described above, according to Embodiment 1, the irradiation position of the laser beam for height position measurement can be adjusted without removing the electron microscope tube 102 (column).

[0106] The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In the examples described above, only the case of correction for proximity effect was explained, but the invention is not limited to this.

[0107] Furthermore, while descriptions of the device configuration, control methods, and other parts not directly necessary for explaining the present invention have been omitted, it goes without saying that the necessary device configuration and control methods can be appropriately selected and used. For example, although the control unit configuration for controlling the drawing device 100 has been omitted, it goes without saying that the necessary control unit configuration can be appropriately selected and used.

[0108] Furthermore, all multi-charged particle beam lithography methods, multi-charged particle beam lithography apparatuses, irradiation position measurement substrates, laser beam irradiation position adjustment methods, and laser beam irradiation position evaluation systems that incorporate elements of the present invention and can be appropriately modified by those skilled in the art are included within the scope of the present invention. [Explanation of Symbols]

[0109] 12,14 Spot Statue 13,15 Center of gravity position 20 Multi-electron beam 22 holes 24 control electrodes 25 Passing hole 26 Counter electrode 28 pixels 29 Sub-irradiation area 30 drawing area 32 Stripe Area 34 Irradiation area 36 pixels 41 Control circuits 50 Rasterization Processing Unit 52 Dose calculation unit 54 Irradiation time calculation unit 60 I / F circuit 62 Communication Control Unit 64 Irradiation position adjustment section 66 Correction amount calculation section 67 Judgment section 68 memory 69 Storage device 70 Data Processing Department 71 CM circuit 72 Drawing Control Unit 73 Center of gravity calculation circuit 74 Transfer Processing Unit 75 memory 76 Storage device 78 Control Management Circuit 80,90 light source 81,91 XY Stages 82,92 Miller 83,93 lenses 84,94 Half Mirror 85,95 lens 86,96 Miller 87,97 Lens 88,98 sensors 100 Drawing device 101 samples 102 Electronic Microscope Tube 103 Drawing room 105 XY Stages 110 Control Computer 112 memory 130 Deflection control circuit 132,134 DAC Amplifier Unit 135 z sensor control circuit 136 Lens control circuit 138 Stage control mechanism 139 Stage position measuring instrument 140,142 Storage device 150 Drawing mechanism 160 Control System Circuits 200 electron beam 201 Electron Gun 202 Illumination Lens 203 Molded aperture array substrate 204 Blanking Aperture Array Mechanism 205 Reduction Lens 206 Limiting Aperture Substrate 207 Objective lens 208 Main deflector 209 Sub deflector 210 Mirror 220,230 Height position sensor 300 Irradiation position measurement board 302 Main board 304 2D Sensor 306 Control Circuit 308 Power supply 309 Interface (I / F) Circuit 330 Membrane area 400 calculator

Claims

1. A circuit board body that can be placed on a stage inside the device, A two-dimensional sensor mounted on the aforementioned substrate body measures the intensity distribution of incident laser light, A power supply for driving the two-dimensional sensor is mounted on the aforementioned circuit board body, The aforementioned circuit board includes an interface circuit mounted on the main body that outputs information based on measurement results to an external device, A substrate for measuring irradiation position, characterized by having the following features.

2. The irradiation position measuring substrate according to claim 1, further comprising a control circuit mounted on the substrate body, which inputs information on the measured intensity distribution and calculates the centroid position of the laser beam.

3. The control circuit calculates the centroid position of the incident light while the irradiation position measuring substrate is placed on the stage, The irradiation position measuring substrate according to claim 2, characterized in that the interface circuit wirelessly transmits the calculated center of gravity position to an external source.

4. The irradiation position measuring substrate according to claim 1 or 2, characterized in that the outer periphery of the substrate body is formed to have the same shape and size as the sample placed on the stage.

5. The apparatus has a stage on which a sample is placed, a microscope tube having an illumination optical system, and an illumination mechanism that irradiates laser light to measure the height position of the surface of the sample on the stage, The main circuit board and A two-dimensional sensor mounted on the aforementioned substrate body measures the intensity distribution of incident laser light, A power supply for driving the two-dimensional sensor is mounted on the aforementioned circuit board body, The aforementioned circuit board includes an interface circuit mounted on the main body that outputs information based on measurement results to an external device, A step of adjusting the irradiation position of the laser beam that irradiates the irradiation position measuring substrate while an irradiation position measuring substrate having the above is placed on it, The steps include irradiating the irradiation position measuring substrate with the laser light and measuring the intensity distribution of the laser light using the two-dimensional sensor, A step of calculating the centroid position of the laser beam using information on the intensity distribution of the laser beam measured by the two-dimensional sensor, A step of calculating a correction amount to correct the deviation of the center of gravity of the laser beam from a predetermined position using the calculated center of gravity position, Equipped with, The process of adjusting the irradiation position of the laser beam, measuring the intensity distribution of the laser beam, calculating the center of gravity of the laser beam, and calculating a correction amount to correct the deviation of the center of gravity of the laser beam is repeated until the amount of deviation of the center of gravity of the laser beam falls within an acceptable range. A method for adjusting the irradiation position of laser light, characterized by the features described above.

6. A circuit board body that can be placed on a stage inside the device, A two-dimensional sensor mounted on the aforementioned substrate body measures the intensity distribution of incident laser light, A power supply for driving the two-dimensional sensor is mounted on the aforementioned circuit board body, The aforementioned circuit board includes an interface circuit mounted on the main body that outputs information based on measurement results to an external device, A substrate for measuring the irradiation position having, It is connected to the aforementioned irradiation position measuring board in a manner that allows it to communicate with the board. A receiving unit that receives information on the light intensity distribution measured by the two-dimensional sensor or information on the centroid position of the laser beam calculated using the intensity distribution information, via the interface circuit. A calculation unit that uses the received intensity distribution or the centroid position to calculate a correction amount to correct the deviation of the centroid position of the laser beam from a predetermined position, A determination unit that determines whether the amount of deviation of the centroid position of the laser beam is within an acceptable range, A computer having, A laser beam irradiation position evaluation system characterized by comprising the following features.

7. A circuit board body that can be placed on a stage inside the device, A two-dimensional sensor mounted on the aforementioned substrate body measures the intensity distribution of incident laser light, A power supply for driving the two-dimensional sensor is mounted on the aforementioned circuit board body, The aforementioned circuit board includes an interface circuit mounted on the main body that outputs information based on measurement results to an external device, A substrate for measuring the irradiation position having, It is connected to the aforementioned irradiation position measuring board in a manner that allows it to communicate with the board. A receiving unit that receives information on the light intensity distribution measured by the two-dimensional sensor via the interface circuit, A centroid position calculation unit calculates the centroid position of the laser beam using the received intensity distribution information, A calculation unit calculates a correction amount to correct the deviation of the center of gravity of the laser beam from a predetermined position using the calculated center of gravity position, A determination unit that determines whether the amount of deviation of the centroid position of the laser beam is within an acceptable range, A computer having, A laser beam irradiation position evaluation system characterized by comprising the following features.

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