Charged particle beam drawing method, charged particle beam drawing device, and program

Abstract

To reduce variations of beam irradiation positions.SOLUTION: A charged particle beam drawing method deflects a charged particle beam by a deflector, irradiates a substrate where a resist film is formed with the charged particle beam, and draws a pattern. The method irradiates a pattern region where the pattern is formed with a beam in a first irradiation amount, irradiates at least a part of a non-pattern region where the pattern is not formed with the charged particle beam in a second irradiation amount that does not allow the resist film to be resolved, and the second irradiation amount is determined on the basis of the first irradiation amount, and a charge amount of the resist film according to pattern density of the pattern region. A difference between the charge amount of the pattern region and a charge amount of a non-resolution irradiation region irradiated in the second irradiation amount is smaller than that in a case in which the second irradiation amount is zero.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a charged particle beam drawing method, a charged particle beam drawing apparatus, and a program. [Background technology]

[0002] As LSIs become more highly integrated, the circuit line width required for semiconductor devices is becoming finer every year. To form the desired circuit pattern on a semiconductor device, a method is adopted in which a high-precision original pattern (called a mask, or a reticle, especially when used in steppers and scanners) formed on quartz is reduced and transferred onto a wafer using a reduction projection exposure system. The high-precision original pattern is drawn using an electron beam drawing system, using so-called electron beam lithography technology.

[0003] When an electron beam is irradiated onto a substrate such as a mask, the irradiation position and its surroundings can become charged by previous electron beam irradiation, resulting in a misalignment of the irradiation position. One conventional method for eliminating this beam irradiation position misalignment is to form an anti-charge film (CDL: Charge Dissipation Layer) on the substrate to prevent charging of the substrate surface. However, this anti-charge film essentially has acidic properties, making it incompatible with substrates coated with chemically amplified resist. Furthermore, forming the anti-charge film requires additional equipment, further increasing manufacturing costs.

[0004] For this reason, a technology called Charging Effect Correction (CEC) has been proposed that performs charging effect correction without using an anti-charge film. Conventional charging effect correction has the problem that as the difference in the amount of charge between regions increases, the correction residual increases, resulting in greater variation in the beam irradiation position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 61-202430 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-93726 [Patent Document 3] Japanese Patent Application Publication No. 5-267140 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a charged particle beam drawing method, a charged particle beam drawing apparatus, and a program that can reduce variations in the beam irradiation position. [Means for solving the problem]

[0007] A charged particle beam lithography method according to one embodiment of the present invention is a charged particle beam lithography method that deflects a charged particle beam using a deflector and irradiates the charged particle beam onto a substrate on which a resist film has been formed to draw a pattern, wherein the beam is irradiated onto a pattern area where a pattern is to be formed with a first irradiation amount, and the charged particle beam is irradiated onto at least a portion of a non-pattern area where a pattern is not to be formed with a second irradiation amount at which the resist film is not resolved, the second irradiation amount being determined based on the first irradiation amount and the charge amount of the resist film corresponding to the pattern density of the pattern area, and the difference between the charge amount of the pattern area and the charge amount of the non-resolved irradiation area irradiated with the second irradiation amount is smaller than when the second irradiation amount is zero.

[0008] A charged particle beam lithography apparatus according to one aspect of the present invention is a charged particle beam lithography apparatus that deflects a charged particle beam by a deflector and irradiates the charged particle beam onto a substrate on which a resist film has been formed to draw a pattern, the apparatus comprising: an emission unit that emits the charged particle beam; a storage unit that stores charge amount information that indicates a relationship between a first irradiation amount of the charged particle beam, a pattern density, and a charge amount of the resist film in a pattern area, which is an area where a pattern based on drawing data is to be formed; and a storage unit that refers to the charge amount information and calculates the first irradiation amount and the pattern density in the pattern area. The device comprises a non-resolution irradiation amount calculation unit that calculates a second irradiation amount when irradiating the charged particle beam to a non-pattern area where no pattern is to be formed, based on the charge amount of the resist film calculated from the density, so that the resist film is not resolved and the difference between the charge amount of the pattern area and the charge amount of the non-resolved irradiation area irradiated with the second irradiation amount is smaller than when the second irradiation amount is zero, and a drawing unit that irradiates the pattern formation area with the charged particle beam at the first irradiation amount and irradiates the non-pattern area with the charged particle beam at the second irradiation amount.

[0009] A program according to one aspect of the present invention causes a computer to execute the following steps: irradiating a substrate on which a resist film has been formed with a charged particle beam and calculating a first dose of the charged particle beam for resolving the resist film to form a pattern; and calculating a second dose when irradiating the charged particle beam to a non-pattern region of the substrate where no pattern is formed, based on the first dose and a charge amount of the resist film corresponding to the pattern density of the pattern region where the pattern is formed, so that the resist film is not resolved and the difference in charge amount between the pattern region and the non-resolved irradiation region irradiated with the second dose is smaller than when the second dose is zero. [Effects of the Invention]

[0010] According to the present invention, it is possible to reduce variations in the beam irradiation position. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a drawing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating the state of stage movement. [Figure 3] FIG. 3a shows the test layout used to measure the resist charging effect, and FIG. 3b is a schematic diagram of the box array. [Figure 4] 4a and 4b are graphs showing charge amount information. [Figure 5] 10 is a flowchart illustrating a drawing method according to the embodiment. [Figure 6] FIG. 10 is a diagram showing an example of a non-resolved illumination region. [Figure 7] 1 is a histogram of pattern density. [Figure 8] FIG. 10 is a diagram illustrating an example of calculation of a target charge amount. [Figure 9] FIG. 10 is a diagram showing an example of calculation of a non-resolved irradiation amount. [Figure 10] FIG. 10a is a diagram showing a drawing layout, FIG. 10b is a diagram showing an error in the beam irradiation position according to a comparative example, and FIG. 10c is a diagram showing an error in the beam irradiation position according to the same embodiment. [Figure 11] FIG. 10 is a diagram showing an example of a non-resolved illumination region. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and an ion beam or the like may also be used.

[0013] FIG. 1 is a schematic diagram of a lithography apparatus according to an embodiment. The lithography apparatus 100 shown in FIG. 1 includes a lithography unit W and a control unit C. The lithography apparatus 100 is an example of an electron beam lithography apparatus. The lithography unit W includes an electron lens barrel 1 and a lithography chamber 14. Inside the electron lens barrel 1, an electron gun 5, an illumination lens 7, a first aperture plate 8, a projection lens 9, a shaping deflector 10, a second aperture plate 11, an objective lens 12, an objective deflector 13, an electrostatic lens 15, and a blanking deflector 16 are arranged.

[0014] An XY stage 3 is placed in the patterning chamber 14. A substrate 2 to be patterned is placed on the XY stage 3. The substrate 2 includes a photomask used for exposure in semiconductor manufacturing and a semiconductor wafer for forming a semiconductor device. The photomask to be patterned also includes a mask blank on which nothing has yet been patterned. For example, the substrate 2 has quartz, a chrome film provided on the quartz, and a resist layer provided on the chrome film. A mirror 4 for measuring the stage position is placed on the XY stage 3 at a position different from the position where the substrate 2 is placed.

[0015] A calibration mark M is provided on the XY stage 3 at a position different from the position where the substrate 2 is placed. For example, the mark M is a metal cross shape, and the mark M is scanned with an electron beam, and the reflected electrons from the mark M are detected by a detector (not shown) to perform focus adjustment, position adjustment, adjustment of the deflection shape correction coefficient, etc.

[0016] The control unit C includes control computers 110 and 120, a stage position detection unit 45, a stage control unit 46, a deflection control circuit 130, a memory 142, and storage devices 21 and 140 such as magnetic disk devices. The deflection control circuit 130 is connected to the blanking deflector 16, the shaping deflector 10, and the objective deflector 13.

[0017] The control computer 110 has the functions of a writing control unit 30 that controls the entire apparatus, a pattern density distribution calculation unit 32, a non-resolved irradiation region setting unit 35, a charge amount determination unit 36, and a non-resolved irradiation amount calculation unit 38. Each unit of the control computer 110 may be configured with hardware including an electric circuit, a computer, a processor, a circuit board, a quantum circuit, or a semiconductor device, or may be configured with software. Input data and calculation results of each unit of the control computer 110 are stored in a memory 142.

[0018] The control computer 120 has the functions of the shot data generation unit 41. The shot data generation unit 41 may be configured as software or hardware.

[0019] The deflection control circuit 130 has the functions of a blanking control unit 42, a shaping deflector control unit 43, and an objective deflector control unit 44. The blanking control unit 42, the shaping deflector control unit 43, and the objective deflector control unit 44 may be configured by software or by hardware.

[0020] The storage device 140 stores drawing data (layout data) that defines a plurality of graphic patterns to be drawn.

[0021] An electron beam 6 emitted from an electron gun 5 (emitter) illuminates the entire first aperture plate 8, which has a rectangular hole, via an illumination lens 7. Here, the electron beam 6 is first shaped into a rectangle. After passing through the first aperture plate 8, the electron beam 6 as a first aperture image is projected onto a second aperture plate 11 by a projection lens 9. The position of the first aperture image on the second aperture plate 11 is deflected by a shaping deflector 10 controlled by a shaping deflector control unit 43, making it possible to change the beam shape and dimensions (variable shaping).

[0022] The electron beam 6 of the second aperture image that has passed through the second aperture plate 11 is focused by the objective lens 12, deflected by, for example, an electrostatic deflector (objective deflector 13) controlled by an objective deflector control unit 44, and irradiated onto a desired position on the substrate 2 on a movably arranged XY stage 3. The XY stage 3 is driven and controlled by a stage control unit 46. The position of the XY stage 3 is detected by a stage position detection unit 45. The stage position detection unit 45 includes, for example, a laser length measurement device that irradiates the mirror 4 with a laser and measures the position based on the interference between the incident light and the reflected light. The electrostatic lens 15 dynamically corrects the focal position of the electron beam 6 in accordance with unevenness on the surface of the substrate 2 (dynamic focus).

[0023] FIG. 2 is a diagram for explaining how the stage moves. When drawing on the substrate 2, the XY stage 3 is moved continuously in, for example, the X direction. The drawing area is virtually divided into a plurality of rectangular stripe regions (SR) by the deflectable width of the electron beam 6. The drawing process is performed in stripe region units. The movement of the XY stage 3 in the X direction is, for example, continuous, and at the same time, the shot position of the electron beam 6 is made to follow the stage movement. Continuous movement can shorten the drawing time.

[0024] After writing one stripe area, the XY stage 3 is stepped in the Y direction and the next stripe area is written in the X direction (reverse direction). By writing each stripe area in a zigzag pattern, the movement time of the XY stage 3 can be shortened.

[0025] When processing layout data (writing data), the writing device 100 virtually divides the writing area into a plurality of rectangular frame areas, and data processing is performed for each frame area. When multiple exposure is not performed, the frame area and the stripe area are usually the same area. When multiple exposure is performed, the frame area and the stripe area are shifted depending on the degree of multiplicity. In this way, the writing area of ​​the substrate 2 is virtually divided into a plurality of frame areas (stripe areas) that serve as writing unit areas, and the writing unit W writes for each frame area (stripe area).

[0026] When an electron beam is irradiated onto the resist layer of the substrate 2, the irradiated position and its surroundings become charged. Variations in the beam irradiation position occur due to differences in the amount of charge between areas where a pattern is formed (beam-irradiated areas) and areas where a pattern is not formed (areas not irradiated with the beam). The inventors discovered that by irradiating areas where a pattern is not formed with the beam to an extent that the resist is not resolved, and by making the amount of charge on the resist surface uniform across the entire substrate, it is possible to suppress variations in the beam irradiation position.

[0027] In this embodiment, when calculating the beam irradiation amount (non-resolution irradiation amount) to be applied to the region where no pattern is to be formed so that the resist is not resolved, the beam irradiation amount D exp The relationship between the pattern density p and the charge amount C in the pattern area C(p,D exp ) is calculated and registered in the storage device 21 as charge amount information.

[0028] Charge amount information C(p,D exp ) can be experimentally determined from the results of drawing a test layout disclosed in, for example, Japanese Patent No. 5480496. FIG. 3A shows the test layout used to measure the resist charging effect. Note that in FIG. 3A, the scale has been changed to make the contents of each part easier to understand.

[0029] The test layout shown in Figure 3a is a grid (81 x 81 grid) with a pitch L1 of 1 mm and a side length L2 of 80 mm. After that, an irradiation pad with a pattern density p and a side length L3 of 40 mm is placed in the center of the layout with a beam irradiation dose D exp This is achieved by drawing a second box array on the same grid as the first box array, after drawing the irradiation pad.

[0030] As shown enlarged in Figure 3b, the first box array is a square pattern with a side length L4 of 4 μm, for example, and the second box array is a frame-shaped pattern with a side length L5 of 14 μm, which is larger than the first box array and has a hollowed-out center.

[0031] The above test layouts are formed by varying the pattern density and the amount of irradiation of the irradiation pad.

[0032] The positions of the drawn first and second box arrays are measured using the resist image measurement method, and the position of the first box array is subtracted from the position of the second box array to measure the positional deviation due to the charging effect of the irradiation pad, thereby obtaining the positional deviation distribution P1 from the design position due to the charging effect of the irradiation pad.

[0033] Using the assumed response function r(x, y) for calculating the misalignment amount from the charge amount distribution, the charge amount can be calculated from the misalignment amount distribution as follows: First, the irradiation pad is uniformly set at 1 nC / cm 2 The displacement distribution P0 when assuming that the area is charged is expressed as follows: 2 In the area other than the irradiation pad, the function C0(x, y) is calculated by convolution of the response function r(x, y) with a function C0(x, y) that is zero.

[0034]

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[0035] The amount of charge on the pad can be calculated from the slope of the correlation between P0 and the measurement result P1. The amount of charge is calculated for each test layout obtained by varying the pattern density and dose.

[0036] Charge amount information C(p,D exp ) is the index of the number of electrons irradiated per unit volume, pD exp Using the variables, it can be calculated as shown in Figure 4a.

[0037] Beam irradiation dose D exp is the resist resolution dose D from the proximity effect correction formula. th , and the backscattering coefficient η, the following equation (2) holds. Therefore, the charge amount information C(p,D exp ) can also be expressed as shown in Figure 4b, with the pattern density p as a variable.

[0038]

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[0039] The charge amount information C(p,D exp 5, a drawing method using a drawing device in which the pattern density distribution data (D) registered in the storage device 21 is described. This drawing method includes a pattern density distribution calculation step (step S100), a non-resolved irradiation region determination step (step S102), a charge amount determination step (step S104), a non-resolved irradiation amount calculation step (step S106), and a drawing step (step S108).

[0040] In the pattern density distribution calculation step (step S100), the pattern density distribution calculation unit 32 reads out the drawing data from the storage device 140, virtually divides the drawing area (or frame area) into a mesh shape with predetermined dimensions (grid dimensions), and calculates the pattern density, which indicates the arrangement ratio of the figure pattern defined in the drawing data, for each mesh area. Then, the pattern density distribution for each mesh area is created.

[0041] In the non-resolution irradiation region determination step (step S102), the non-resolution irradiation region determination unit 35 determines a non-resolution irradiation region to be irradiated with a beam at a non-resolution irradiation dose. For example, as shown in Fig. 6, among the non-pattern regions where no pattern is formed, a region separated from the edge of the pattern region by a distance L0, which is not affected by backscattered electrons due to pattern irradiation (not affected by the proximity effect), is determined as the non-resolution irradiation region R1. The distance L0 is, for example, about 30 µm.

[0042] In the charge amount determination step (step S104), the charge amount determination unit 36 ​​determines a target charge amount Ct in the non-resolved irradiation region. For example, the charge amount Ct is set to the charge amount Ct corresponding to the most frequently occurring pattern density (irradiation amount) in the drawing layout.

[0043] For example, a pattern density histogram such as that shown in FIG. 7 can be obtained based on the pattern density for each mesh region calculated by the pattern density distribution calculation unit 32. The most frequently occurring pattern density in this histogram is extracted. The average or median value of the pattern density may also be used. At this time, pattern densities of 0% are excluded.

[0044] The charge amount determining unit 36 ​​determines the charge amount information C(p,D exp ) and determine the target charge amount Ct from the charge amount corresponding to the extracted pattern density. Figure 8 shows an example of the charge amount Ct when the extracted pattern density is 60%. Note that the charge amount Ct is determined based on the resist resolution dose D th However, it is not necessary to strictly match the charge amount corresponding to the pattern density, and it is sufficient if the variation in the charge amount is suppressed to a certain extent. In other words, it is sufficient if the difference between the charge amount in the pattern area and the charge amount in the non-resolved irradiation area is smaller than when the non-resolved irradiation area is not irradiated with a beam.

[0045] In the non-resolution irradiation amount calculation step (step S106), the non-resolution irradiation amount calculation unit 38 calculates the charge amount information C(p,D exp ) to calculate the non-resolution irradiation amount to obtain the charge amount Ct. At this time, for example, as shown in FIG. 9, pD expwhere pD exp There are two solutions (A1, A2) for the resist resolution dose D th If we take a 30% margin of resolution dose D th In the non-resolution irradiation area, a predetermined irradiation density, for example, a solid pattern (p=100%) is irradiated, so the selected pD exp The non-resolved dose is calculated from

[0046] In the drawing process (step S108), the shot data generation unit 41 in the control computer 120 reads drawing data from the storage device 140 and performs multiple stages of data conversion processing to generate shot data in a format specific to the drawing apparatus 100. The size of a figure pattern defined in the drawing data is usually larger than the shot size that the drawing apparatus 100 can form in one shot. Therefore, in the drawing apparatus 100, each figure pattern is divided into multiple shot figures (shot division) so that the size is such that the drawing apparatus 100 can form in one shot. Then, for each shot figure, data such as a figure code indicating the figure type, coordinates, and size are defined as shot data.

[0047] At this time, the shot data generating unit 41 generates shot data assuming that a solid pattern exists in the non-resolved irradiation region determined in step S102.

[0048] The shot data generation unit 41 performs proximity effect correction calculations and the like for the pattern region, calculates the dose (irradiation time) for each shot, and defines it in the shot data. Also, for the non-resolution irradiation region, the shot data generation unit 41 defines the non-resolution irradiation dose calculated in step S106 in the shot data.

[0049] In the deflection control circuit 130, the shaping deflector control unit 43 calculates, in shot order, the deflection amount of the shaping deflector 10 for variably shaping the electron beam 6 based on the figure type and size defined in the shot data for each shot figure. Also, the objective deflector control unit 44 calculates the deflection amount of the objective deflector 13 for deflecting the electron beam 6 to the position on the substrate 2 where the shot figure is to be irradiated. Then, the objective deflector 13 arranged in the electron lens barrel 1 deflects the electron beam according to the calculated deflection amount, thereby drawing a pattern on the substrate 2.

[0050] Furthermore, the blanking control unit 42 controls the blanking deflector 16 based on the irradiation amount (irradiation time) defined in the shot data, and controls the irradiation amount for each shot.

[0051] When a pattern was written using the conventional charging effect method without applying the method of this embodiment to the writing layout shown in Fig. 10a, the correction residual became large at the boundary between the patterned area and the non-patterned area, as shown in Fig. 10b. On the other hand, when a pattern was written using the method of this embodiment, it was confirmed that the variation in the beam irradiation position could be reduced.

[0052] Thus, according to this embodiment, a non-pattern area is irradiated with a non-resolved dose of beam, and the charge amount on the resist surface is made uniform across the entire substrate, thereby suppressing variation in the beam irradiation position.

[0053] In the above embodiment, an example was described in which an area located a distance L0 from the pattern is defined as the non-resolved irradiation area R1, but as shown in Figure 11, the entire area other than the pattern (non-pattern area) may also be defined as the non-resolved irradiation area R2.

[0054] In this case, the irradiation amount B of the non-resolved irradiation area R2 exp is determined from the pattern distribution so as to satisfy the proximity effect correction formula shown in the following formula (3): g(x) in formula (3) is a function representing backscattering.

[0055]

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[0056] Once the pattern density p is defined, it can be expressed as in the following equation (4).

[0057]

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[0058] The charge amount Q is determined by the pattern density p and the irradiation amount D exp , beam irradiation amount B in the non-resolved irradiation area R2 exp For example, p, D exp , B exp The test layout shown in Figure 3a is drawn by changing the value of the charge amount Q(p,D exp ,B exp ) is calculated. exp ,B exp ) can be expressed as a polynomial such as equation (5).

[0059]

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[0060] For any pattern density p, the charge amount Q(p,D exp ,B exp ) so that B exp Determine the non-resolved dose B for the mask area with pattern density p. exp is a function of charge amount and irradiation amount Q(p,D exp (B exp ),B exp )=const. Here, D exp (B exp ) is a function that satisfies the proximity effect correction formula. exp If there is no solution, B exp is a predetermined constant irradiation amount.

[0061]

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[0062] B on the entire board exp When this is obtained, the charge distribution becomes uniform and the variation in the beam irradiation position can be suppressed.

[0063] B on the entire board exp Even if this cannot be calculated, the effect can be obtained if the difference in charge amount between the pattern area and the non-pattern area is smaller than when the non-pattern area is not irradiated. However, the charge amount may remain uneven, and the effect will be partial. In this case, CEC (Charge Effect Correction) using charge amount prediction may be used in combination.

[0064] In the above embodiment, a single-beam drawing apparatus has been described, but the present invention can also be applied to a multi-beam drawing apparatus.

[0065] Misalignment of the irradiation position due to charging phenomena is not limited to electron beam lithography systems, but the present invention can be applied to any charged particle beam system that uses the results obtained by irradiating a targeted position with a charged particle beam, such as an inspection system that inspects patterns with a charged particle beam such as an electron beam.

[0066] In the above embodiment, in order to reduce the effect of fogging caused by electrons scattered within the drawing chamber falling onto the substrate and to make direct charging by the irradiated electron beam dominant, a positive potential may be applied to the lower surface of the objective lens 12 (objective optical system) to prevent secondary electrons from being returned to the substrate surface.

[0067] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0068] 1 Electron telescope 2 boards 3 XY stage 4. Mirror 5. Electron gun 6. Electron Beam 7 Lighting lens 8 First Aperture Plate 9 Projection Lens 10 deflector 11 Second aperture plate 12 Objective Lens 13 Deflector 14 Drawing room 15 Electrostatic Lens 16 Blanking deflector 21,140 Storage device 30 Drawing control unit 32 Pattern density distribution calculation unit 35 Non-resolved irradiation area determination unit 36 Charge amount determination unit 38 Non-resolution exposure calculation unit 41 Shot data generation unit 42 Blanking control section 43 Molding deflector control section 44 Objective deflector control section 45 Stage position detection unit 46 Stage control section 100 drawing device

Claims

1. 1. A charged particle beam lithography method for irradiating a substrate on which a resist film has been formed with a charged particle beam by deflecting the charged particle beam with a deflector, thereby drawing a pattern, comprising: irradiating a pattern area where a pattern is to be formed with a beam at a first dose; irradiating at least a portion of a non-patterned region where a pattern is not formed with the charged particle beam at a second dose that does not resolve the resist film; a charge amount of the resist film corresponding to the pattern density of the pattern area, and a difference between the charge amount of the pattern area and the charge amount of a non-resolved irradiation area irradiated with the second dose is smaller than that when the second dose is zero.

2. 2. The charged particle beam writing method according to claim 1, wherein the charged particle beam is irradiated with the second dose onto an area of ​​the non-patterned area that is a predetermined distance away from the patterned area.

3. 2. The charged particle beam writing method according to claim 1, wherein the charged particle beam is irradiated onto the entire non-pattern region with the second dose.

4. 1. A charged particle beam lithography apparatus that deflects a charged particle beam by a deflector and irradiates a substrate on which a resist film is formed with the charged particle beam to draw a pattern, an emission section that emits the charged particle beam; a storage unit that stores charge amount information indicating a relationship between a first irradiation amount of the charged particle beam, a pattern density, and a charge amount of the resist film in a pattern region where a pattern based on drawing data is formed; a non-resolution irradiation amount calculation unit that refers to the charge amount information and calculates a second irradiation amount when irradiating the charged particle beam to a non-pattern area where no pattern is to be formed, based on the first irradiation amount and the charge amount of the resist film calculated from the pattern density of the pattern area, so that the resist film is not resolved and a difference between the charge amount of the pattern area and the charge amount of a non-resolution irradiation area irradiated with the second irradiation amount is smaller than when the second irradiation amount is zero; a writing unit that irradiates the pattern region with the charged particle beam at the first dose and irradiates the non-pattern region with the charged particle beam at the second dose; A charged particle beam writing apparatus comprising:

5. irradiating a substrate on which a resist film has been formed with a charged particle beam and calculating a first dose of the charged particle beam for resolving the resist film to form a pattern; calculating a second irradiation amount when irradiating a non-pattern area of ​​the substrate where no pattern is formed with the charged particle beam based on the first irradiation amount and a charge amount of the resist film corresponding to a pattern density of the pattern area where the pattern is formed, so that the resist film is not resolved and a difference between the charge amount of the pattern area and the charge amount of a non-resolved irradiation area irradiated with the second irradiation amount is smaller than when the second irradiation amount is zero; A program that causes a computer to execute the following.

Images