Data generation method, charged particle beam irradiation device, and computer-readable recording medium

Abstract

The present invention provides a data generation method, a charged particle beam irradiation device, and a computer-readable recording medium, which can calculate the pixel coverage of a graph containing a curve at high speed and accurately. The data generation method of one embodiment of the present invention divides a parameter curve that represents the shape of a depicted pattern and is defined by a plurality of control points sequentially arranged in a specified direction at the positions of extreme values ​​and inflection points to generate a plurality of parameter elements, extracts a portion of control points from the plurality of control points for each parameter element, sequentially connects the extracted control points in the specified direction to generate a polygon, calculates the coverage of each of the plurality of rectangular divided areas obtained by dividing the irradiation object of the charged particle beam with a specified size based on the polygon, finds the intersection points of the plurality of parameter elements and the four sides of the plurality of divided areas, and calculates the coverage of the divided areas of the peripheral portion of the depicted pattern.

Description

[0001] This application is based on Japanese Patent Application No. 2021-130792 (filing date: August 10, 2021), and claims the priority of this basic application. This application incorporates all the contents of the basic application by reference thereto. Technical Field

[0002] The present invention relates to a data generation method, a charged particle beam irradiation apparatus, and a computer-readable recording medium. Background Art

[0003] With the high integration of LSIs, the circuit line width required for semiconductor devices has been miniaturized year by year. In order to form a desired circuit pattern on a semiconductor device, the following method is adopted: a reduction projection exposure apparatus is used to reduce and transfer a high-precision original pattern formed on quartz onto a wafer. In the production of a high-precision original pattern, a so-called electron beam lithography technique is used in which a resist is exposed by an electron beam drawing apparatus to form a pattern.

[0004] As an electron beam drawing apparatus, for example, a multi-beam drawing apparatus is known which uses a multi-beam to irradiate a large number of beams at once to improve the processing ability. In this multi-beam drawing apparatus, for example, an electron beam emitted from an electron gun passes through an aperture member having a plurality of openings, thereby forming a multi-beam, and each beam is blanking-controlled in a blanking plate. The unshielded beam is reduced in an optical system and irradiated to a desired position on a mask to be drawn.

[0005] In the case of performing electron beam drawing using a multi-beam drawing apparatus, for each pixel divided into a predetermined size, the coverage rate of the input pattern is calculated, and the irradiation amount of each beam is controlled. When the input pattern includes a curve, the coverage rate can be relatively easily calculated by approximating it as a polygon. However, if the approximation is performed with high precision, the number of vertices of the approximated polygon increases, and there is a problem that data processing takes a long time. Summary of the Invention

[0006] The present invention provides a data generation method, a charged particle beam irradiation apparatus, and a program that can calculate the pixel coverage rate of a graph including a curve at high speed and accurately.

[0007] A data generation method according to an aspect of the present invention divides a parametric curve that represents the shape of a drawn pattern and is defined by a plurality of control points arranged in a specified direction at the positions of extreme values and inflection points to generate a plurality of parametric elements. For each parametric element, a part of the control points is extracted from the above-mentioned plurality of control points, and the extracted control points are sequentially connected in the above-mentioned specified direction to generate a polygon. The coverage rate of each of a plurality of rectangular divided regions obtained by dividing the irradiation object of the charged particle beam by a specified size based on the above-mentioned polygon is calculated, the intersections of the above-mentioned plurality of parametric elements and the four sides of the above-mentioned plurality of divided regions are obtained, and the coverage rate of the divided regions of the peripheral portion of the above-mentioned drawn pattern is calculated. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of a multi-charged particle beam drawing apparatus according to an embodiment of the present invention.

[0009] Figure 2 is a top view of a shaping aperture array plate.

[0010] Figure 3 is a flowchart for explaining a drawing method.

[0011] Figure 4 is a diagram for explaining a drawing operation.

[0012] Figure 5 is a flowchart for explaining a method for generating a pixel map.

[0013] Figure 6a is a diagram showing an example of a B-spline curve, Figure 6b is a diagram showing an example of a Bezier curve, Figure 6c is a diagram showing a conversion formula.

[0014] Figure 7a is a diagram showing an example of a Bezier curve, Figure 7b is a diagram showing an example of the division of a Bezier curve, Figure 7c A diagram showing an example of a Bezier element.

[0015] Figure 8a is a diagram showing an example of a Bezier curve, Figure 8b is a diagram showing an example of the division of a Bezier curve, Figure 8c is a diagram showing an example of an internal polygon.

[0016] Figure 9a is a diagram showing an example of the classification of Bezier elements, Figure 9b is a diagram showing an example of a Bezier basic element.

[0017] Figure 10 is a mathematical formula for explaining an intersection calculation method.

[0018] Figure 11This is a diagram showing an example of an intersection point.

[0019] Figure 12 This is a diagram explaining the method for calculating intersection points.

[0020] Figure 13 This is a diagram showing a calculation example of pixel coverage rate.

[0021] Explanation of symbols

[0022] 100: Drawing device; 110: Control computer; 111: Area density calculation unit; 112: Irradiation time calculation unit; 113: Data processing unit; 114: Drawing control unit. Detailed implementation mode

[0023] A data generation method according to an aspect of the present invention divides a parametric curve that represents the shape of a drawn pattern and is defined by a plurality of control points arranged in a specified direction at the positions of extreme values and inflection points to generate a plurality of parametric elements. For each parametric element, a part of the control points is extracted from the above-mentioned plurality of control points, and the extracted control points are sequentially connected in the above-mentioned specified direction to generate a polygon. The coverage rate of each of a plurality of rectangular divided regions obtained by dividing the irradiation object of the charged particle beam with a specified size based on the above-mentioned polygon is calculated, the intersection points of the above-mentioned plurality of parametric elements and the four sides of the above-mentioned plurality of divided regions are calculated, and the coverage rate of the divided regions on the peripheral portion of the above-mentioned drawn pattern is calculated.

[0024] Hereinafter, embodiments of the present invention will be described based on the drawings. In the embodiments, as an example of the charged particle beam, a configuration using an electron beam will be described. However, the charged particle beam is not limited to an electron beam, and may be an ion beam or the like.

[0025] Figure 1 This is a schematic configuration diagram of the drawing device according to the embodiment. As Figure 1 shown, the drawing device 100 includes a drawing unit 150 and a control unit 160. The drawing device 100 is an example of a multi-charged particle beam drawing device. The drawing unit 150 includes an electron column 102 and a drawing chamber 103. An electron gun 201, an illumination lens 202, a shaping aperture array plate 203, a blanking aperture array plate 204, a reduction lens 205, a limiting aperture member 206, an objective lens 207, and a deflector 208 are arranged in the electron column 102.

[0026] An XY stage 105 is arranged in the drawing chamber 103. A substrate 101 to be drawn is arranged on the XY stage 105. The substrate 101 is, for example, a mask blank or a semiconductor substrate (silicon wafer). In addition, a mirror 210 for position measurement is arranged on the XY stage 105.

[0027] The control unit 160 includes a control computer 110, a deflection control circuit 130, a stage position detector 139, and a storage unit 140. Drawing data is input from the outside and stored in the storage unit 140. In the drawing data, information defining a plurality of graphic patterns that describe the patterns formed on the substrate 101 is defined. As will be described later, graphic patterns including curves are defined in shape by cubic B-spline curves.

[0028] The control computer 110 includes an area density calculation unit 111, an irradiation time calculation unit 112, a data processing unit 113, and a drawing control unit 114. Each unit of the control computer 110 may be constituted by hardware such as a circuit, or may be constituted by software such as a program that executes these functions. Alternatively, it may be constituted by a combination of hardware and software.

[0029] The stage position detector 139 irradiates a laser beam onto the mirror 210 and receives the reflected light, and detects the position of the XY stage 105 based on the principle of laser interferometry.

[0030] Figure 2 is a conceptual diagram showing the configuration of the shaping aperture array plate 203. As Figure 2 shown, in the shaping aperture array plate 203, a plurality of openings 203a are formed at a predetermined arrangement pitch along the longitudinal direction (y direction) and the lateral direction (x direction). Preferably, each opening 203a is formed of a rectangle or a circle having the same size and shape. A part of the electron beam 200 passes through these plurality of openings 203a, thereby forming multi-beams 20a to 20e.

[0031] In the blanking aperture array plate 204, through holes are formed at positions corresponding to the arrangement positions of the respective openings 203a of the shaping aperture array plate 203. In each through hole, a blanker constituted by a group of two pairs of electrodes is arranged. By grounding, for example, one of the two electrodes of the blanker to maintain a ground potential and switching the other electrode to a ground potential or a potential other than the ground potential, the on / off of the deflection of the beam passing through the through hole is switched, and blanking control is performed. When the blanker does not deflect the beam, the beam is turned on. When the blanker deflects the beam, the beam is cut off. In this way, the plurality of blankers perform blanking deflection of the respective corresponding beams in the multi-beams after passing through the plurality of openings 203a of the shaping aperture array plate 203.

[0032] The electron beam 200 emitted from the electron gun 201 (emission unit) illuminates the entire shaping aperture array plate 203 with the aid of the illumination lens 202. The electron beam 200 illuminates the area including all the openings 203a. The electron beam 200 passes through the plurality of openings 203a of the shaping aperture array plate 203, thereby forming a plurality of electron beams (multi-beams) 20a to 20e having, for example, a rectangular shape.

[0033] Multiple beams 20a to 20e pass through inside the blankers respectively corresponding to the blanking aperture array plate 204. The blankers respectively perform blanking deflection on the cut-off beams in the individually passing electron beams. The blankers do not perform blanking deflection on the turned-on beams. The multiple beams 20a to 20e after passing through the blanking aperture array plate 204 are reduced by the reduction lens 205 and travel toward the central opening formed in the limiting aperture member 206.

[0034] Here, the beams controlled to the beam cut-off state are deflected by the blankers and pass through the orbit outside the opening of the limiting aperture member 206, so they are blocked by the limiting aperture member 206. On the other hand, the beams controlled to the beam on state are not deflected by the blankers, so they pass through the opening of the limiting aperture member 206. In this way, blanking control is performed by the on / off deflection of the blankers to control the cut-off / turn-on of the beams. The blanking aperture array plate 204 has the function of an irradiation time control unit for controlling the irradiation time of each beam of the multiple beams.

[0035] The limiting aperture member 206 allows the beams deflected by the blankers of the blanking aperture array plate 204 to the beam on state to pass through and blocks the beams deflected by the blankers of the blanking aperture array plate 204 to the beam cut-off state. Then, a multiple beam for one emission is formed by using the beam after passing through the limiting aperture member 206 formed from the beam on to the beam cut-off.

[0036] The multiple beams after passing through the limiting aperture member 206 are focused by the objective lens 207 to form a pattern image with a desired reduction ratio on the substrate 101. Each beam (the whole multiple beam) after passing through the limiting aperture member 206 is deflected in the same direction together by the deflector 208 and irradiated to the desired position on the substrate 101.

[0037] When the XY stage 105 moves continuously, at least during the period of irradiating the beam to the substrate 101, control is performed by the deflector 208 so that the irradiation position of the beam follows the movement of the XY stage 105. The multiple beams for one irradiation are ideally arranged at intervals obtained by multiplying the arrangement interval of the multiple openings 203a of the shaping aperture array plate 203 by the above-mentioned desired reduction ratio.

[0038] Next, based on Figure 3The flowchart shown below illustrates the pattern drawing method of this embodiment. In the pattern area density calculation step (step S1), the area density calculation unit 111 hypothetically divides the drawing area of the substrate 101 to be irradiated with the beam into a plurality of grid areas. The size of the grid area is, for example, a size similar to that of one beam, and each grid area is a pixel (unit irradiation area). The area density calculation unit 111 reads the drawing data from the storage unit 140, calculates the pattern area density (coverage rate) ρ of each pixel (rectangular divided area) using the pattern defined in the drawing data, and generates a pixel map defining the coverage rate of each pixel. The method for generating the pixel map will be described later.

[0039] In the irradiation time calculation step (step S2), the irradiation time calculation unit 112 multiplies the pattern area density ρ by the reference irradiation amount D0 to calculate the irradiation amount ρD0 of the beam irradiated to each pixel. The irradiation time calculation unit 112 may further multiply by a correction factor for correcting the proximity effect and the like. The irradiation time calculation unit 112 divides the irradiation amount by the current amount of each of the multiple beams constituting the multi-beam to calculate the irradiation time of each of the multiple beams.

[0040] In the irradiation time control data generation step (step S3), the data processing unit 113 rearranges the irradiation time data in the emission order according to the drawing order to generate irradiation time control data.

[0041] In the data transmission step (step S4), the drawing control unit 114 outputs the irradiation time control data to the deflection control circuit 130. The deflection control circuit 130 outputs the irradiation time control data to each blanker of the blanking aperture array board 204.

[0042] In the drawing step (step S5), the drawing control unit 114 controls the drawing unit 150 to perform a drawing process on the substrate 101. Each blanker of the blanking aperture array board 204 switches the on / off of the beam based on the irradiation time control data to give a desired exposure amount to each pixel.

[0043] Figure 4 is a conceptual diagram for explaining the drawing operation. As Figure 4 shown, the drawing area 80 of the substrate 101 is hypothetically divided into a plurality of strip-shaped areas 82 with a specified width in the y direction (first direction). First, the XY stage 105 is moved and adjusted so that the irradiation area (beam array) 84 that can be irradiated by one-time irradiation of the multi-beam is located at the left end of the first strip-shaped area 82, and the drawing is started.

[0044] When depicting the first bar region 82, it is depicted relatively in the +x direction by moving the XY stage 105 in the -x direction. The XY stage 105 moves continuously at a prescribed speed. After the depiction of the first bar region 82 is completed, the stage position is moved in the -y direction and adjusted so that the beam array 84 is located at the right end of the second bar region 82. Then, by moving the XY stage 105 in the +x direction, it is depicted in the -x direction.

[0045] In the third bar region 82, it is depicted in the +x direction, and in the fourth bar region 82, it is depicted in the -x direction. By depicting while alternately changing the direction, the depiction time can be shortened. In addition, each bar region 82 can also be depicted always in the same direction, that is, either the +x direction or the -x direction.

[0046] Next, based on Figure 5 the flowchart shown, the pixel map generation method of the area density calculation unit 111 will be described.

[0047] The area density calculation unit 111 reads out the drawing data from the storage unit 140 and converts the curve of the drawn graphic pattern (drawing pattern) defined by the cubic B-spline curve into a cubic Bezier curve (step S101). For example, the Figure 6a cubic B-spline curve shown is converted into the Figure 6b cubic Bezier curve shown. Figure 6c An example of the conversion formula is shown.

[0048] In the cubic Bezier curve, as shown in Figure 7a , the curve is represented by four control points. That is, in the example shown in Figure 6b , the part where the group of four control points is continuous surrounds the periphery of the graphic. Two of the four control points, the start point and the end point, are located on the curve. The multiple control points are defined and arranged in a prescribed direction, clockwise or counterclockwise, in sequence along the periphery of the graphic.

[0049] The area density calculation unit 111 divides the curve shown by the four control points into finer Bezier curves at the positions of the extreme values and inflection points (step S102). The inflection point is a point where the curvature = (dPx / dt)(dPy2 / dt2) - (dPy / dt)(dPx2 / dt2) = 0. The extreme value is a point where dPx / dt = 0 and dPy / dt = 0.

[0050] Hereinafter, the Bezier curve divided at the positions of the extreme values and inflection points will be called a Bezier element. For example, each of the Bezier curves shown in Figure 7a includes one maximum value, minimum value, and inflection point. Therefore, as shown in Figure 7b , it is divided into four Bezier elements B1 to B4.

[0051] As Figure 7c shown, each Bezier element is a curve element that monotonically increases or decreases in the X direction and the Y direction.

[0052] Figure 8a is the same as Figure 6b the figure, showing the Bezier curve before segmentation at the positions of the extreme values and the inflection points. Figure 8b represents the Bezier curve (Bezier element) after segmentation.

[0053] Next, for each of the multiple Bezier elements, a part of the control points is extracted from the multiple control points, and the extracted control points are connected by straight lines in the original defined order (clockwise or counterclockwise along the perimeter of the figure) to generate a polygon (hereinafter referred to as the "inner polygon") (step S103). In the present embodiment, the start point and the end point of each Bezier element are extracted to generate the inner polygon. For example, by connecting Figure 8b the start point and the end point of each Bezier element shown, Figure 8c the inner polygon shown is generated.

[0054] The inner polygon is divided into triangles by a conventionally known method (step S104). It is not necessarily a triangle, but a trapezoid can also be used for the division.

[0055] Using the triangles obtained by dividing the inner polygon, the coverage rate (area density) of each pixel based on the inner polygon is calculated to generate the first pixel map (step S105).

[0056] Based on the slope of the line segment connecting the start point and the end point, and on which side (left or right) of the line segment the control points other than the start point and the end point are located in the traveling direction, each Bezier element is classified into Figure 9a the eight types shown (step S106).

[0057] Each Bezier element is rotated and inverted to become Figure 9b the basic Bezier element shown (step S107).

[0058] For each pixel, it is determined whether the boundary line of the pixel intersects the curve of the basic Bezier element (step S108). As Figure 10 shown, by solving the cubic equation combining the Bezier curve and the straight line representing the pixel boundary, the intersection points are obtained. For example, obtain Figure 11The intersection points P1 and P2 shown. At this time, when an intersection point exists on the left side L or the bottom side B of the pixel, the remaining intersection points exist on the upper side T or the right side R. When no intersection point exists on the left side L and the bottom side B, no intersection point exists on this pixel. The maximum number of intersection points per pixel is two. By considering this situation, intersection determination can be effectively performed.

[0059] As Figure 12 shown, the curve from t = 0 to t = 1 on the curve can also be divided by Δt, the coordinates on the curve are calculated at each position, and based on the coordinate values of the points t i and the previous point t i-1 that exceed the pixel boundary within Δt, intersection determination is calculated by linear interpolation. At this time, interpolation calculation is performed on t based on each coordinate value. Here, coordinate calculations at intervals of Δt can also be performed in parallel using threads such as a GPU.

[0060] When the boundary line of the pixel intersects the curve of the Bezier element, as Figure 13 shown, the inside of the pixel is divided into a triangular part (A1, A3) and a curve sector part (A2), and the areas of each are calculated. The area of the curve sector part is obtained by a line integral with the intersection points with the pixel as the range.

[0061] The areas of the triangular part and the curve sector part are added together, the coverage rate of the pixel is calculated, and a second pixel map is generated (step S109). The coverage rate calculated here is the coverage rate of the pixels at the peripheral part (outer peripheral part) of the graphic (drawn pattern). In addition, when the Bezier element is located inside the line of the inner polygon, the calculated coverage rate is multiplied by -1.

[0062] An image map obtained by performing the reverse operations of rotation and inversion performed in step S107 on the second pixel map is added to the first pixel map generated in step S105 to generate a third pixel map (step S110). When the beam irradiation amount irradiated to each pixel is calculated by the irradiation time calculation unit 112, this third pixel map is used.

[0063] In this way, according to the present embodiment, the Bezier curve is divided into finer Bezier curves (Bezier elements) at the extreme values and inflection points. Therefore, the intersection points of each pixel and the Bezier element are set to a maximum of two, and intersection calculation and coverage rate calculation become easy, and pixel coverage rate calculation can be performed at high speed and accurately.

[0064] Without using the method of the above-described embodiment, in the case of a Bézier curve (parametric curve), depending on the degree of the curve, it sometimes crosses one side of the divided region (pixel) multiple times or crosses three or more sides. Considering various crossing methods to calculate the coverage rate results in an increase in the processing amount. On the other hand, when the parametric curve is divided at the extreme values and inflection points as in the above-described embodiment, the divided curve elements become a shape that monotonically increases or decreases in one direction. Therefore, when a curve element intersects the four sides (right side, upper side, left side, lower side) of the boundary of the divided region, the number of crossings is two, and it crosses different sides. Therefore, the crossing method of the curve element with the boundary of the divided region is simplified, the coverage rate calculation becomes easy, and the processing amount can be reduced. In addition, compared with the conventional coverage rate calculation based on polygon approximation, the number of elements to be processed is smaller and there is no approximation, so the coverage rate calculation can be performed at high speed and accurately.

[0065] The multiple Bézier elements generated by dividing the Bézier curve can be used as units for parallel processing. For example, they can be effectively used in the parallel operations of a GPU, enabling high-speed processing.

[0066] In the above-described embodiment, an example of converting to a cubic Bézier curve was described, but the degree is not limited to 3.

[0067] In the above-described embodiment, an example of representing the input graphic by a B-spline was described, but as long as it can be converted into a Bézier curve, a graphic represented by other parametric curves can also be set as the input data.

[0068] The above processing can also be performed using other parametric curves other than the Bézier curve. The parametric curve is divided at the extreme values and inflection points to generate multiple parametric elements. At least one of the multiple control points included in each parametric element is sequentially connected by a line to generate an internal polygon. The intersection points of the multiple parametric elements and the pixel boundary are obtained, the pixel coverage rate of the peripheral part of the graphic is calculated, and based on this pixel coverage rate and the pixel coverage rate of the internal polygon, the coverage rate of each pixel is obtained.

[0069] In the above-described embodiment, a drawing device for drawing a pattern on a substrate was described, but it can also be applied to other irradiation devices such as inspection devices that irradiate a beam to an object. In addition, in the above-described embodiment, a multi-beam irradiation device that irradiates multiple beams at once using multiple beams was described, but the same method can also be applied to a single-beam irradiation device that irradiates one beam to the irradiated substrate.

[0070] At least a part of the control computer 110 may be constituted by hardware or software. In the case of being constituted by software, a program that implements at least a part of the functions of the control computer 110 may be stored in a recording medium such as a floppy disk or a CD-ROM, and read and executed by a computer. The recording medium is not limited to detachable media such as magnetic disks and optical disks, and may also be a fixed-type recording medium such as a hard disk device or a memory.

[0071] In addition, a program that implements at least a part of the functions of the control computer 110 may be distributed via a communication line such as the Internet (including wireless communication). Furthermore, it may be distributed in a state where the program is encrypted, modulated, or compressed via a wired or wireless line such as the Internet, or stored in a recording medium for distribution.

[0072] In addition, the present invention is not directly limited to the above-described embodiments, and constituent elements can also be deformed and embodied within the scope of not departing from the gist thereof at the implementation stage. Furthermore, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, several constituent elements may be deleted from all the constituent elements shown in the embodiments. Furthermore, constituent elements related to different embodiments may be appropriately combined.

Claims

1. A charged particle beam irradiation method, characterized in that: A parameter curve representing the shape of the drawing pattern and defined by a plurality of control points arranged sequentially in a predetermined direction is divided at the positions of extreme values ​​and inflection points to generate a plurality of parameter elements. For each parameter element, a portion of control points are extracted from the plurality of control points, and the extracted control points are sequentially connected in the predetermined direction to generate a polygon. calculating the coverage rate of each of a plurality of rectangular divided regions obtained by dividing the irradiation target of the charged particle beam into predetermined sizes, based on the polygon; The intersection points of the plurality of parameter elements and the four sides of the plurality of rectangular divided areas are obtained, and the coverage of the divided areas of the peripheral portion of the drawing pattern is calculated. Based on the above coverage, the irradiation amount to each divided area is calculated. The charged particle beam irradiation device is controlled to irradiate the irradiation object with the charged particle beam at the calculated irradiation amount, thereby drawing a pattern on the irradiation object.

2. The charged particle beam irradiation method according to claim 1, characterized in that: The above parametric curve is a Bezier curve.

3. The charged particle beam irradiation method according to claim 2, characterized in that: The above Bezier curve is divided at the extreme value and inflection point to generate multiple Bezier elements. The polygon is generated by extracting a start point and an end point from a plurality of control points respectively included in the plurality of Bezier elements, and sequentially connecting the extracted start points and end points with straight lines in the predetermined direction.

4. The charged particle beam irradiation method according to claim 1, characterized in that: The divided area is divided into a triangular portion and a curved sector portion by using the intersection points of the parameter elements and the four sides of the divided area, and the area of ​​the triangular portion is added to the area of ​​the curved sector portion to calculate the coverage of the divided area.

5. A computer-readable recording medium storing a program, characterized in that: The above program causes the computer to execute the following steps: A step of dividing a parameter curve representing a shape of a drawing pattern and defined by a plurality of control points arranged sequentially in a predetermined direction at positions of extreme values ​​and inflection points to generate a plurality of parameter elements; For each parameter element, a step of extracting a portion of control points from the plurality of control points, and sequentially connecting the extracted control points in the specified direction to generate a polygon; a step of calculating a coverage rate based on the polygon for each of a plurality of rectangular divided regions obtained by dividing the irradiation target of the charged particle beam into predetermined sizes; A step of finding intersection points of the plurality of parameter elements and four sides of the plurality of rectangular divided areas, and calculating coverage of the divided areas of the peripheral portion of the depicted pattern; A step of calculating the irradiation amount to each divided area based on the above coverage rate; and A step of controlling a charged particle beam irradiation device to irradiate the irradiation object with the charged particle beam at the calculated irradiation amount, and drawing a pattern on the irradiation object.

6. The computer-readable recording medium according to claim 5, wherein: The above parametric curve is a Bezier curve.

7. The computer-readable recording medium according to claim 6, wherein: The above program causes the computer to execute the following processing: A process of dividing the Bezier curve at the positions of the extreme values ​​and the inflection points to generate a plurality of Bezier elements; and A process of extracting a start point and an end point from a plurality of control points respectively included in the plurality of Bezier elements, and sequentially connecting the extracted start points and end points with straight lines in the predetermined direction to generate the polygon.

8. The computer-readable recording medium according to claim 5, wherein: The above program enables the computer to perform the following processing: using the intersection of the above parameter elements and the four sides of the above divided area, the above divided area is divided into a triangular part and a curved sector part, the area of ​​the above triangular part is added to the area of ​​the above curved sector part, and the coverage rate of the divided area is calculated.

9. A charged particle beam irradiation device comprising: an irradiation unit that irradiates a charged particle beam onto an object; and A control unit divides a parameter curve representing the shape of a depicted pattern and defined by a plurality of control points arranged sequentially in a specified direction at positions of extreme values ​​and inflection points to generate a plurality of parameter elements, extracts a portion of control points from the plurality of control points for each parameter element, sequentially connects the extracted control points in the specified direction to generate a polygon, calculates coverage rates based on the polygons for each of a plurality of rectangular divided areas obtained by dividing the irradiation object of the charged particle beam with a specified size, finds intersection points of the plurality of parameter elements and the four sides of the plurality of rectangular divided areas, calculates coverage rates of the divided areas of the peripheral portion of the depicted pattern, calculates an irradiation amount to each divided area based on the coverage rates, and controls the irradiation unit to obtain the calculated irradiation amount. The irradiation unit irradiates the object with the charged particle beam at the calculated irradiation amount to draw a pattern on the object.

10. The charged particle beam irradiation device according to claim 9, characterized in that: The above parametric curve is a Bezier curve.

11. The charged particle beam irradiation device according to claim 10, characterized in that: The control unit is: The above Bezier curve is divided at the extreme value and inflection point to generate multiple Bezier elements. The polygon is generated by extracting a start point and an end point from a plurality of control points respectively included in the plurality of Bezier elements, and sequentially connecting the extracted start points and end points with straight lines in the predetermined direction.

12. The charged particle beam irradiation device according to claim 9, characterized in that: The control unit divides the divided area into a triangular portion and a curved sector portion using the intersection points of the parameter element and the four sides of the divided area, adds the area of ​​the triangular portion and the area of ​​the curved sector portion, and calculates the coverage of the divided area.

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