Charged particle beam drawing device, charged particle beam drawing method and storage medium

Abstract

Reduce the difference between the calculated value of the drift amount and the actual drift amount. A charged particle beam drawing device according to one embodiment of the present invention comprises: a deflector for adjusting the irradiation position of the charged particle beam relative to a substrate placed on a workbench; an emission data generating unit for generating emission data including the emission position of each emission and the beam on / off time according to the drawing data; a drift correction unit for calculating the drift amount of the irradiation position of the charged particle beam irradiated to the substrate with reference to the generated plurality of emission data, and generating correction information for correcting the irradiation position deviation based on the drift amount; a deflection control unit for controlling the deflection amount based on the deflector based on the emission data and the correction information; and a virtual irradiation instruction unit for instructing the execution of virtual irradiation of irradiating the charged particle beam to a position different from the substrate on the workbench with a pre-calculated irradiation amount during drawing processing.

Description

Technical Field

[0001] The present invention relates to a charged particle beam drawing device, a charged particle beam drawing method and a storage medium. Background Art

[0002] With the high integration of LSI, the circuit line width required by semiconductor devices is becoming smaller and smaller year by year. In order to form the desired circuit pattern on the semiconductor device, the following method is adopted: using a reduced projection exposure device, the high-precision original pattern (mask, or especially also called intermediate mask used in steppers and scanners) formed on quartz is reduced and transferred to the wafer. The high-precision original pattern is drawn by an electron beam drawing device, using the so-called electron beam lithography technology.

[0003] In electron beam drawing devices, the irradiation position of the electron beam may drift over time during drawing due to various reasons. This phenomenon is called beam drift. For example, contaminants may be attached to the irradiation system of the deflection electrode of the drawing device, and the contaminants may be charged by scattered electrons from the drawing target substrate, causing beam drift. In order to eliminate this beam drift, drift correction is performed.

[0004] For example, Patent Document 1 discloses a method in which the drift amount is calculated based on a correction calculation formula using the beam current amount, beam irradiation position, and beam on / off time of each shot as parameters, and the deflection amount based on the deflector is corrected. However, since the charge accumulation amount on the deflector surface is calculated for each shot, the amount of calculation increases as the number of shots increases.

[0005] In addition, in such conventional methods, in order to achieve high-precision drift correction, it is necessary to accurately know the irradiation information of the beam. In actual drawing processing, unexpected drawing interruptions may occur due to waiting for data transmission and temporary stop of drawing, but the drawing interruption is not taken into account in the correction calculation. Therefore, the error between the calculated drift amount and the actual drift amount gradually accumulates and expands over time, which sometimes affects the drawing accuracy.

[0006] Patent Document 1: Japanese Patent No. 4439038

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 60-85519

[0008] Patent Document 3: Japanese Patent Application Publication No. 2010-267909

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 9-45602

[0010] Patent Document 5: Japanese Patent No. 2956628

[0011] Patent Document 6: Japanese Patent Application Laid-Open No. 5-304080

[0012] Patent Document 7: Japanese Patent Application Publication No. 2001-319853 Summary of the invention

[0013] An object of the present invention is to provide a charged particle beam drawing device, a charged particle beam drawing method, and a charged particle beam drawing program capable of reducing the difference between a calculated value of a drift amount and an actual drift amount.

[0014] A charged particle beam drawing device according to one embodiment of the present invention comprises: an emission unit that emits a charged particle beam; a deflector that adjusts the irradiation position of the charged particle beam relative to a substrate placed on a workbench; an emission data generating unit that generates emission data including the emission position of each emission and the beam on / off time according to the drawing data; a drift correction unit that refers to the generated plurality of emission data, calculates the drift amount of the irradiation position of the charged particle beam irradiated to the substrate based on the emission positions and the beam on / off time of the plurality of emissions, and generates correction information for correcting the irradiation position deviation based on the drift amount; a deflection control unit that controls the deflection amount based on the deflector based on the emission data and the correction information; and a virtual irradiation instruction unit that, in the drawing process, instructs the execution of virtual irradiation of the charged particle beam to a position on the workbench different from the substrate with a pre-calculated irradiation amount.

[0015] A charged particle beam drawing method according to one embodiment of the present invention comprises: a process of emitting a charged particle beam; a process of adjusting the irradiation position of the charged particle beam relative to a substrate placed on a workbench using a deflector; a process of generating emission data including the emission position of each emission and the beam on / off time according to drawing data; a process of calculating the drift amount of the irradiation position of the charged particle beam irradiated to the substrate based on the emission positions and the beam on / off time of the multiple emissions with reference to the generated multiple emission data; a process of generating correction information for correcting the irradiation position offset based on the drift amount; a process of controlling the deflection amount based on the emission data and the correction information; and a process of performing virtual irradiation of the charged particle beam to a position on the workbench different from the substrate with a pre-calculated irradiation amount during the drawing process.

[0016] A storage medium according to one embodiment of the present invention is a storage medium storing a program, wherein the program causes a computer to perform the following processing: a process of emitting a charged particle beam; a process of adjusting the irradiation position of the charged particle beam relative to a substrate placed on a workbench using a deflector; a process of generating emission data including the emission position of each emission and the beam on / off time based on drawing data; a process of calculating the drift amount of the irradiation position of the charged particle beam irradiated to the substrate based on the emission positions and beam on / off times of multiple emissions with reference to the generated multiple emission data; a process of generating correction information for correcting the irradiation position offset based on the drift amount; a process of controlling the deflection amount based on the emission data and the correction information; and a process of performing virtual irradiation of a position on the workbench different from the substrate with a pre-calculated irradiation amount during the drawing process.

[0017] Effects of the Invention

[0018] According to the present invention, the difference between the calculated value of the drift amount and the actual drift amount can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a charged particle beam imaging device according to an embodiment of the present invention.

[0020] Figure 2 It is a perspective view of the first molding aperture and the second molding aperture.

[0021] Figure 3 This is a conceptual diagram illustrating a deflection area.

[0022] Figure 4 It is a line graph showing the change of the charge storage amount.

[0023] Figure 5 It is a graph showing the function of charging and discharging.

[0024] Figure 6 It is a graph showing the change of the charge storage amount.

[0025] Figure 7 It is a diagram showing an example of a deflection electrode.

[0026] Figure 8 This is a table showing an example of the relationship between the cumulative number of shots and the drift calculation time.

[0027] Fig. 9 It is a graph showing changes in the calculated drift amount value and the actual drift amount in the comparative example.

[0028] Fig.10 It is a graph showing the relationship between the virtual irradiation time and the improvement amount of the drift amount error.

[0029] Fig.11 This is a graph showing changes in the calculated drift amount and the actual drift amount when virtual irradiation is performed.

[0030] Fig.12 1 is a flowchart for explaining the charged particle beam drawing method according to this embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a configuration using an electron beam is described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and may be an ion beam or the like.

[0032] Figure 1 1 is a conceptual diagram showing the structure of a drawing device according to an embodiment. Figure 1 In the drawing device 100, a drawing unit 150 and a control unit 160 are provided. The drawing unit 150 includes an electron lens barrel 102 and a drawing chamber 103. An electron gun 201, an illumination lens 202, a blanking deflector 212, a blanking aperture 214, a first shaping aperture 203, a projection lens 204, a shaping deflector 205, a second shaping aperture 206, an objective lens 207, a main deflector 208, a sub-deflector 209, and a sub-sub-deflector 216 are arranged in the electron lens barrel 102.

[0033] An XY stage 105 movable in the XY direction is arranged in the drawing chamber 103. A substrate 101 to be drawn, coated with a resist, is arranged on the XY stage 105. The substrate 101 includes an exposure mask, a silicon wafer, a mask blank, etc. used in manufacturing semiconductor devices.

[0034] On the XY stage 105, an irradiated member 107 to be irradiated with an electron beam during dummy irradiation described later is provided at a position different from the region where the substrate 101 is disposed. The irradiated member 107 is, for example, a Faraday cup for measuring the beam current of the electron beam or a reflective mark for measuring the drift amount of the electron beam.

[0035] The reflective mark is, for example, in a cross shape or a dot shape, and is formed of a heavy metal such as tantalum or tungsten on a silicon substrate. An irradiation position detector 220 is provided above the XY stage 105, which detects the irradiation position (beam position) of the electron beam by irradiating the reflective mark with an electron beam. As the irradiation position detector 220, for example, an electron detector that detects the reflected electrons reflected by the mark as a current value by scanning the mark with an electron beam can be used. The detected beam position is notified to the control computer 110 described later.

[0036] When the electron beam 200 emitted from the electron gun 201 (emission unit) provided in the electron column 102 passes through the blanking deflector 212 , whether or not the electron beam is irradiated onto the substrate is switched by the blanking deflector 212 .

[0037] The electron beam 200 passes through the illumination lens 202 and is directed toward a rectangular opening A1 (see Figure 2 ) is irradiated with the first shaping aperture 203. The electron beam 200 is shaped into a rectangular shape by passing through the opening A1 of the first shaping aperture 203.

[0038] The electron beam 200 having passed through the first aperture image of the first shaping aperture 203 is projected by the projection lens 204 onto a projection lens having a variable shaping aperture A2 (see Figure 2 ) on the second molding aperture 206. At this time, the first aperture image projected onto the second molding aperture 206 can be deflected and controlled by the molding deflector 205, so that the shape and size of the electron beam passing through the variable molding opening A2 can be changed (variable molding can be performed).

[0039] The electron beam 200 of the second aperture image after passing through the variable forming opening A2 of the second forming aperture 206 is focused by the objective lens 207, deflected by the main deflector 208, the sub-deflector 209 and the sub-sub-deflector 216, and irradiated to the substrate 101 mounted on the continuously moving XY worktable 105.

[0040] The control unit 160 includes a control computer 110 , a memory 112 , a deflection control circuit 120 , DAC (digital-to-analog converter) amplifiers 130 , 132 , 134 , 136 , and 138 (deflection amplifiers), and a storage device 140 .

[0041] The deflection control circuit 120 is connected to DAC amplifiers 130, 132, 134, 136, and 138. The DAC amplifier 130 is connected to the blanking deflector 212. The DAC amplifier 132 is connected to the sub-deflector 209. The DAC amplifier 134 is connected to the main deflector 208. The DAC amplifier 136 is connected to the sub-deflector 216. The DAC amplifier 138 is connected to the shaping deflector 205.

[0042] The control computer 110 includes an emission data generating unit 50, a drift correcting unit 52, a virtual irradiation instructing unit 53, and a drawing control unit 54. Each function of the emission data generating unit 50, the drift correcting unit 52, the virtual irradiation instructing unit 53, and the drawing control unit 54 may be constituted by software or hardware.

[0043] Figure 3 This is a conceptual diagram used to illustrate the deflection area. Figure 3As shown, the drawing area 10 of the substrate 101 is virtually divided into a plurality of strip-shaped areas 20 in a long strip shape, for example, in the y direction, by the deflectable width of the main deflector 208. Furthermore, the area formed by dividing the strip-shaped area 20 in the x direction by the deflectable width of the main deflector 208 becomes the deflection area of ​​the main deflector 208 (main deflection area).

[0044] The main deflection area is virtually divided into a plurality of subfields (SF) 30 in a grid shape according to the deflectable size of the auxiliary deflector 209. Each SF 30 is virtually divided into a plurality of lower subfields (here, the abbreviation of Tertiary Deflection Field, which means the third deflection, is used as "TF". The same applies hereinafter) 40 in a grid shape according to the deflectable size of the auxiliary deflector 216. An emission pattern is drawn at each emission position 42 of each TF 40.

[0045] The digital signal for blanking control is output from the deflection control circuit 120 to the DAC amplifier 130. The digital signal is converted into an analog signal in the DAC amplifier 130, amplified and applied as a deflection voltage to the blanking deflector 212. The electron beam 200 is deflected by the deflection voltage, and blanking control of each emission is performed.

[0046] The deflection control circuit 120 outputs a digital signal for shaping deflection to the DAC amplifier 138. The DAC amplifier 138 converts the digital signal into an analog signal, amplifies the signal, and applies the signal as a deflection voltage to the deflector 205. The electron beam 200 is deflected to a specific position of the second shaping aperture 206 by the deflection voltage, thereby forming an electron beam of a desired size and shape.

[0047] The digital signal for main deflection control is output from the deflection control circuit 120 to the DAC amplifier 134. The DAC amplifier 134 converts the digital signal into an analog signal, and applies the amplified signal to the main deflector 208 as a deflection voltage. The electron beam 200 is deflected by the deflection voltage, and each emitted beam is deflected to a reference position A (for example, the center position or the lower left corner position of the corresponding SF) of a predetermined subfield (SF) virtually divided in a grid shape. In addition, when the XY stage 105 is continuously moved while drawing, the deflection voltage also includes a tracking deflection voltage for tracking the movement of the stage.

[0048] The digital signal for sub-deflection control is output from the deflection control circuit 120 to the DAC amplifier 132. The DAC amplifier 132 converts the digital signal into an analog signal, amplifies it, and applies it as a deflection voltage to the sub-deflector 209. The electron beam 200 is deflected by the deflection voltage, and each emitted beam is deflected to the reference position B of the TF 40 that becomes the minimum deflection area (for example, the center position of the corresponding TF or the lower left corner position, etc.).

[0049] The deflection control circuit 120 outputs a digital signal for sub-deflection control to the DAC amplifier 136. The DAC amplifier 136 converts the digital signal into an analog signal, amplifies the signal, and applies the signal as a deflection voltage to the sub-deflector 216. The electron beam 200 is deflected by the deflection voltage, and each emitted beam is deflected to each emission position 42 in the TF 40.

[0050] In the drawing device 100, a multi-stage deflector is used to perform drawing processing for each strip area 20. Here, as an example, a three-stage deflector such as a main deflector 208, a sub-deflector 209, and a sub-sub-deflector 216 is used. The XY table 105 draws the first strip area 20 in the x direction while continuously moving in the -x direction. Then, after the drawing of the first strip area 20 is completed, the second strip area 20 is drawn in the same way or in the opposite direction. Hereinafter, the third and subsequent strip areas 20 are drawn in the same way.

[0051] The main deflector 208 deflects the electron beam 200 to the reference position A of the SF30 in sequence so as to follow the movement of the XY stage 105. In addition, the sub-deflector 209 deflects the electron beam 200 from the reference position A of each SF30 to the reference position B of the TF40 in sequence. Then, the sub-sub-deflector 216 deflects the electron beam 200 from the reference position B of each TF40 to the emission position 42 of the beam irradiated into the TF40.

[0052] In this way, the main deflector 208, the sub-deflector 209, and the sub-sub-deflector 216 have deflection areas of different sizes. TF40 is the smallest deflection area among the deflection areas of the multi-stage deflector.

[0053] The storage device 140 is, for example, a magnetic disk device, and stores drawing data for drawing a pattern on the substrate 101. The drawing data is obtained by converting design data (layout data) into a format for the drawing device 100, and is input from an external device to the storage device 140 and stored.

[0054] according to Fig.12 The flowchart shown in the figure illustrates the processing of each part of the control computer 110. The emission data generating unit 50 performs multi-stage data conversion processing on the depiction data stored in the storage device 140, divides each graphic pattern as the depiction object into an emission pattern of a size that can be irradiated by one emission, and generates emission data (step S1) in a format inherent to the depiction device. In the emission data, for example, a graphic code representing the graphic type of each emission graphic, a graphic size (emission size), an emission position, a beam on / off time, etc. are defined for each emission. The generated emission data is temporarily stored in the memory 112.

[0055] Considering the factors causing the size variation of the pattern, such as the proximity effect, the feedforward effect, and the loading effect, the irradiation amount (dose) Q of the electron beam at each position of the drawing area 10 is calculated, and the calculated irradiation amount Q is divided by the current density J, thereby calculating the beam-on time included in the emission data. The beam-off time is calculated based on the worktable movement speed during drawing, the beam movement amount, the stabilization time of the DAC amplifier, etc.

[0056] The generation of the shot data is performed in parallel with the drawing process, and the shot data for a plurality of shots are generated in advance and stored in the memory 112. For example, the shot data for one strip area 20 is generated in advance and stored in the memory 112.

[0057] In this embodiment, the charge accumulation amount on the surface of the deflector (main deflector 208, sub-deflector 209 or sub-sub-deflector 216) is calculated by referring to the emission data of multiple shots generated in advance, using the cumulative number of shots, the averaged emission size (beam size) and emission position (beam deflection position), and the cumulative beam opening / closing time of the multiple shots. Then, the drift amount is calculated based on the charge accumulation amount, and the charged drift caused by the charging phenomenon is corrected in real time.

[0058] In order to correct the charge drift in real time, a correction calculation is performed before the drawing process. In the actual drawing process, the drawing action is sometimes temporarily stopped due to waiting for data transmission, etc., but in order to calculate the charge amount taking into account the drawing stop action generated after the correction calculation is performed first, the correction calculation must be re-performed, which affects the processing volume. Therefore, the influence of the stop time of the drawing action is often not considered, and due to the discharge during the drawing stop, an error occurs between the drift amount calculated and the actual drift amount. Therefore, in this embodiment, in order to reduce the error, virtual irradiation (beam irradiation to the irradiated component 107) is performed at a specified timing to saturate the charge accumulation amount, thereby saturating the drift amount and reducing the difference between the drift amount calculated and the actual drift amount.

[0059] First, the correction calculation is explained. Figure 4 As shown, one transmission has a beam-on period t shot and the beam-off period t stl The charging stage of scattered electrons when beam irradiation (beam on) and the discharging stage when beam off are repeated on the deflector surface.

[0060] The plurality of electrodes constituting the deflector can be used Figure 5 The functions C(t) and D(t) shown in the figure represent the change in the amount of charge accumulated on the electrode surface. Function C(t) represents the charge when the beam is turned on, and function D(t) represents the discharge when the beam is turned off. Figure 5 In the formulas of cis the time constant indicating the ease of charging, τ d is a time constant that indicates the ease of discharge.

[0061] When the general Figure 4 The charge accumulation amount at the start of the i-th emission is Q i When the i-th emission ends (i+1-th emission starts), the charge accumulation amount Q i+1 , the charge accumulation amount Q at the end of the i+1th emission (at the beginning of the i+2th emission) i+2 They can be expressed by the following formula 1. In formula 1, Q max is the saturation electron quantity, t shot is the time the beam is on (transmit time), t stl is the beam-off time (stabilization time), τ c is the charging time constant, τ d is the time constant of discharge.

[0062] [Formula 1]

[0063]

[0064]

[0065] Figure 4 The curve graph shown corresponds to the calculation formula for calculating the charge accumulation amount for each emission. When the charge accumulation amount is calculated for each emission, the amount of calculation increases with the increase in the number of emissions, making it difficult to perform drift correction in real time in parallel with the drawing process. Therefore, in this embodiment, by concentrating multiple emissions to calculate the charge accumulation amount, the calculation speed can be increased and real-time drift correction can be performed.

[0066] For example, in the case of calculating the charge accumulation amount every two shots, by considering the charge accumulation amount as Figure 6 In this case, the charge accumulation amount Q at the end of the (i+1)th emission (at the start of the (i+2)th emission) is i+2 The charge accumulation amount Q at the start of the i-th emission can be i By calculating using the following formula 2, two calculations can be completed at once.

[0067] [Formula 2]

[0068]

[0069] In addition, since the deflector uses multiple electrodes, it is considered that there are multiple power sources. Figure 7As shown in FIG. 1 , the deflector is composed of four electrodes E1 to E4, and the charge accumulation amount (charge amount) of each electrode is calculated every N transmissions (N transmissions are concentrated). The charge accumulation amount Q of the electrode Ej (j=1 to 4) at the start of the i-th transmission can be calculated. i、j , the charge accumulation amount Q after N times of emission can be obtained by the following formula 3: i+N、j .

[0070] [Formula 3]

[0071]

[0072]

[0073]

[0074] Cumulative number of launches: N

[0075] Cumulative launch time: t shot(total)

[0076] Cumulative stabilization time (= cumulative drawing time - cumulative emission time): t stl(total)

[0077] Average deflection direction

[0078] Average emission size:

[0079] In equation 3, the time constant τ cj , τ dj , coefficient α, Q max , j Since it is a state parameter inherent to the device that does not depend on the drawing layout, the beam irradiation amount, the emission interval, and the deflection position can be obtained in advance based on the results of measuring the change in drift under two or more conditions.

[0080] The drift amount can be calculated by the following formula 4 using the charge storage amount of each electrode.

[0081] [Formula 4]

[0082]

[0083] Figure 8 The number of concentrated transmissions (the cumulative number of transmissions N in formula 3) and 1×10 8 An example of the relationship between the time required to calculate the drift amount of the emission. The larger the cumulative number of emissions N, the greater the 1×10 8The less time is required to calculate the drift amount of the transmission, the less time is required to calculate the drift amount of the transmission. In addition, even if the cumulative number of transmissions N is changed to 100, 1000, 10000, 100000, 1000000, the calculated drift amount is almost unchanged.

[0084] Contains the above equations 3 and 4 and the time constant τ cj , τ dj , coefficient α, Q max , j The calculation formula data of is stored in the storage device 140. The drift correction unit 52 obtains the calculation formula data from the storage device 140. The drift correction unit 52 refers to the multiple transmission data stored in the memory 112, calculates the cumulative transmission time (the total time of beam on), the cumulative stabilization time (the total time of beam off), the average deflection direction, and the average transmission size of multiple transmissions, and substitutes the calculated values ​​into the calculation formula to calculate the charge accumulation amount of each electrode.

[0085] The drift correction unit 52 calculates the drift amount based on the charge accumulation amount of each electrode (step S2), and obtains the drift correction amount for eliminating the drift amount. The drift correction unit 52 generates correction information of the deflection amount (beam irradiation position) of the electron beam based on the drift correction amount (step S3), and provides it to the drawing control unit 54. The drawing control unit 54 provides the correction amount of the beam irradiation position to the deflection control circuit 120 using the correction information.

[0086] The drawing control unit 54 transmits the transmission data to the deflection control circuit 120. The deflection control circuit 120 outputs a signal for blanking control to the DAC amplifier 130 and a signal for shaping deflection to the DAC amplifier 138 based on the transmission data.

[0087] The deflection control circuit 120 outputs a signal for deflection control based on the transmission data and the correction amount of the beam irradiation position to the DAC amplifiers 132, 134, and 136. Thus, the beam irradiation position is corrected in the drawing unit 150 (step S4).

[0088] The drift amount calculated by the drift correction unit 52 is different from the actual drift amount because of the time not used for drift amount calculation due to the subsequent unexpected drawing interruption action (temporary drawing stop action such as data transmission waiting and stage waiting). Fig. 9 An example of the calculated drift value, the actual drift value, and the accumulated error value when an event occurs is shown in . It can be seen that the accumulated error increases when the events occurring at time T1, T2, and T3 serve as triggers.

[0089] In this embodiment, the virtual irradiation instruction unit 53 instructs the drawing control unit 54 to execute virtual irradiation at a predetermined timing (step S5_Yes). According to the instruction from the virtual irradiation instruction unit 53, the drawing control unit 54 executes virtual irradiation (step S6). The timing of virtual irradiation is arbitrary, for example, it can be performed at a predetermined time interval, or it can be performed every time a predetermined number of strip areas 20 are drawn. Fig.10 The relationship between the virtual irradiation time and the improvement amount of the drift amount error is shown in the figure, and the appropriate virtual irradiation time is set. If the virtual irradiation time is too short, the improvement amount of the drift amount error becomes insufficient, and if the irradiation time is too long, the processing volume decreases.

[0090] The drift correction unit 52 calculates the drift amount by substituting the irradiation conditions of the virtual irradiation into the above-mentioned calculation formula as the virtual irradiation is executed.

[0091] exist Fig.11 2 shows an example of the change in the calculated drift value and the actual drift value when virtual irradiation is performed. Events occur at times T1, T2, and T3, and virtual irradiation is performed at times T4, T5, T6, and T7. It can be seen that the difference between the calculated drift value and the actual drift value is reduced by virtual irradiation.

[0092] Thus, according to the present embodiment, the drift amount is calculated by referring to a plurality of emission data in a specific interval, using the cumulative number of emissions, the beam size averaged in the interval, the beam deflection position (deflection direction), and the cumulative time of beam on / off in the interval, thereby suppressing the amount of calculation and performing drift correction with high accuracy. In addition, by performing virtual irradiation at a predetermined timing, the difference between the calculated value of the drift amount and the actual drift amount can be reduced, thereby improving the drawing accuracy.

[0093] In the above embodiment, an example of performing virtual irradiation at a predetermined timing regardless of the presence or absence of an event is described. However, in the case where the occurrence and interruption time of the event can be grasped, the virtual irradiation instruction unit 53 may also calculate the discharge amount during the drawing stop, find the error with the drift amount calculation value, and determine the irradiation time of the virtual irradiation according to the size of the error. In addition, the virtual irradiation of the determined irradiation time may be performed once or in multiple times.

[0094] In the above embodiment, a single-beam drawing device is described, but a multi-beam drawing device may be used. In this case, the emission position, beam on / off time, etc. are defined in the emission data.

[0095] At least a part of the charged particle beam delineation device described in the above embodiment may be composed of hardware or software. In the case of being composed of software, a program for realizing at least a part of the function of the multi-beam delineation device may be stored in a storage medium such as a floppy disk or a CD-ROM, and read and executed by a computer. The storage medium is not limited to a removable medium such as a magnetic disk or an optical disk, but may also be a fixed storage medium such as a hard disk device or a memory.

[0096] In addition, the program that realizes at least a part of the functions of the charged particle beam drawing device may be distributed via a communication line (including wireless communication) such as the Internet. Furthermore, the program may be encrypted or modulated and distributed in a compressed state via a wired line such as the Internet, a wireless line, or stored in a storage medium.

[0097] While the present invention has been described in detail using specific embodiments, it will be apparent to one skilled in the art that various modifications can be made without departing from the spirit and scope of the present invention.

[0098] This application is based on Japanese Patent Application No. 2020-017697 filed on February 5, 2020, the entire contents of which are incorporated herein by reference.

[0099] Explanation of symbols:

[0100] 50: emission data generating unit; 52: drift correction unit; 53: virtual irradiation instruction unit; 54: drawing control unit; 100: drawing device; 107: irradiated component; 110: control computer; 150: drawing unit; 160: control unit.

Claims

1. A charged particle beam imaging device comprising: An emission unit for emitting a charged particle beam; a deflector for adjusting an irradiation position of the charged particle beam relative to a substrate placed on a workbench; A transmission data generating unit generates transmission data including a transmission position and a beam on / off time for each transmission based on the depiction data; a drift correction unit that refers to the generated plurality of emission data, calculates a drift amount of an irradiation position of the charged particle beam irradiated onto the substrate based on emission positions and beam on / off times of the plurality of emissions, and generates correction information for correcting an irradiation position deviation based on the drift amount; a deflection control unit that controls a deflection amount of the deflector based on the transmission data and the correction information; and The virtual irradiation instruction unit instructs execution of virtual irradiation of irradiating a position on the stage different from the substrate with the charged particle beam at an irradiation amount obtained in advance during the drawing process.

2. The charged particle beam drawing device according to claim 1, characterized in that: The virtual irradiation instructing unit instructs execution of the virtual irradiation at a predetermined timing or whenever an event occurs.

3. The charged particle beam drawing device according to claim 2, characterized in that: The virtual irradiation instruction unit calculates a discharge amount during a time period not used for calculation of the drift amount, and obtains the irradiation amount of the virtual irradiation based on the discharge amount.

4. The charged particle beam drawing device according to any one of claims 1 to 3, characterized in that: The deflector has a plurality of electrodes. The drift correction unit calculates the charge accumulation amount of each of the plurality of electrodes based on the total beam-on time, the total beam-off time, the average deflection direction, and the average shot size of the plurality of shots, and calculates the drift amount from the charge accumulation amount of each electrode.

5. A charged particle beam drawing method comprising: A process for emitting a charged particle beam; a step of adjusting an irradiation position of the charged particle beam relative to a substrate placed on a stage using a deflector; A step of generating shot data including a shot position and a beam on / off time for each shot based on the depiction data; Referring to the generated plurality of shot data, and calculating a drift amount of an irradiation position of the charged particle beam irradiated onto the substrate based on the emission positions and beam on / off times of the plurality of shots; A step of generating correction information for correcting an irradiation position deviation based on the drift amount; A step of controlling a deflection amount of the deflector based on the emission data and the correction information; and In the drawing process, a step of dummy irradiation is performed in which a position on the stage different from the substrate is irradiated with the charged particle beam at an irradiation amount obtained in advance.

6. The charged particle beam drawing method according to claim 5, characterized in that: The above-mentioned virtual irradiation is performed at a predetermined timing or every time an event occurs.

7. The charged particle beam drawing method according to claim 6, characterized in that: The discharge amount during the time not used for calculation of the drift amount is calculated, and the irradiation amount of the virtual irradiation is obtained based on the discharge amount.

8. The charged particle beam drawing method according to any one of claims 5 to 7, characterized in that: The deflector has a plurality of electrodes. Based on the total beam-on time, the total beam-off time, the average deflection direction and the average emission size of the multiple shots, the charge accumulation amount of each of the plurality of electrodes is calculated, and the drift amount is calculated based on the charge accumulation amount of each electrode.

9. A storage medium is a computer-readable storage medium storing a program, wherein: The above program is used to make the computer execute the following processing: Processing of emitted charged particle beams; A process of adjusting the irradiation position of the charged particle beam relative to the substrate placed on the worktable using a deflector; A process of generating shot data including a shot position and a beam on / off time for each shot based on the depiction data; Referring to the generated plurality of shot data, a process of calculating a drift amount of an irradiation position of the charged particle beam irradiated onto the substrate based on the emission positions and beam on / off times of the plurality of shots; A process of generating correction information for correcting the irradiation position deviation based on the above-mentioned drift amount; Controlling a process based on the deflection amount of the deflector based on the transmission data and the correction information; and In the drawing process, a process of dummy irradiation is performed in which a position on the stage different from the substrate is irradiated with the charged particle beam at an irradiation amount obtained in advance.

Images