JP2009111148A - Drawing data verification method and mask drawing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing data verification method and a mask drawing device, capable of precisely verifying conversion error at data conversion. <P>SOLUTION: The drawing data verification method includes a process (step S4) for acquiring a differential figure between design data and drawing data converted from the design data, a process (step S5) for generating a figure corresponding to a tolerable error region of the region where a difference arises due to an arbitrary angle proximity from an arbitrary angle figure contained in the design data when the design data is converted into the drawing data, and a process (step S6) in which the differential figure is subjected to a process for subtracting a figure corresponding to the tolerable error region, for removing the differential figure in the tolerable error region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drawing data verification method for a charged beam drawing apparatus for forming a pattern with a charged beam and a mask drawing apparatus for the same.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, the line width of a circuit pattern required for manufacturing a semiconductor device has been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam drawing technique has an essentially excellent resolution, and is used to produce a high-precision original pattern.

  As an electron beam drawing apparatus for forming a pattern using the electron beam drawing technique, for example, there is a variable shaping type electron beam drawing apparatus. In this method, an electron beam is shaped into a rectangular shape or a 45 ° triangle (right isosceles triangle) using two apertures, and a light-shielding film on a glass substrate surface coated with a resist is irradiated with the electron beam to form a fine pattern. A drawing device.

  In performing electron beam drawing, first, a layout of a semiconductor integrated circuit is designed. Then, CAD data (design data) is generated as layout data. The design data is converted into drawing data input to the electron beam drawing apparatus. The drawing data is further converted into data in a format in the electron beam drawing apparatus, and then electron beam drawing is performed using the converted data.

  If there is a shift due to conversion between the CAD data 210 and the converted drawing data 212 as shown in FIG. 16, when the XOR verification is performed, the shift before and after the conversion is detected as a difference graphic 214 (the hatched portion in the figure). Is done. When an arbitrary-angle figure 220 as shown in FIG. 17A is defined in the CAD data, a drawing apparatus having a 45-degree trapezoidal or rectangular aperture has an arbitrary-angle figure as shown in FIG. 17B. Drawing data 222 is created by approximately dividing the figure. When XOR verification is performed on such a conversion, a difference graphic 224 (shaded portion in the figure) as shown in FIG. 18 is detected, although this is not a malfunction due to the conversion. In the case where the difference due to the defect at the time of conversion and the difference due to the arbitrary angle approximation are mixed, as shown in FIG. 19, the defect mixed difference may be detected at a location due to the arbitrary angle approximation. In this way, when differences due to arbitrary angle approximation and differences due to defects are mixed and a large number of difference figures are detected, it is difficult to find only differences due to defects, which hinders data verification. .

Here, as a technique for verifying whether drawing data obtained by converting design data is different from the original design data, there is a document having the following contents. In this known document, an exclusive OR (XOR) operation or the like is performed between CAD data (design data) of LSI and EB data (drawing data) after the data conversion. Then, a logical product (AND) operation is performed between the obtained difference graphic and the design data, and an operation is performed to efficiently determine whether or not there is a conversion error at the time of data conversion based on the presence or absence of the number of figures to be output. (For example, refer to Patent Document 1).
JP 2001-344302 A

  In the above background art, when differences due to arbitrary angle approximation at the time of data conversion and differences due to defects are mixed and a large number of difference figures are detected, it is difficult to find only the differences due to defects, and data There is a problem that hinders verification.

  An object of the present invention is to solve the above problems and provide a drawing data verification method and a mask drawing apparatus that perform conversion error verification at the time of data conversion with high accuracy.

The drawing data verification method according to an embodiment of the present invention includes a step of obtaining a difference graphic between design data and drawing data converted from the design data, and the design data is converted into drawing data when the design data is converted into drawing data. A step of generating a figure corresponding to an allowable error area of an area where a difference caused by arbitrary angle approximation is generated from an arbitrary angle figure included, and a process of subtracting the figure corresponding to the allowable error area from the difference figure And a step of removing the difference graphic in the allowable error region.

  In the drawing data verification method of the present invention, it is desirable that the figure corresponding to the allowable error region is generated based on a predetermined arbitrary angle approximation value.

In the drawing data verification method of the present invention, it is preferable that the graphic corresponding to the allowable error region is generated based on an arbitrary angle approximation value corresponding to an arbitrary angle.
The drawing data verification method according to another embodiment of the present invention includes a step of obtaining a difference graphic between design data and drawing data converted from the design data, and when the design data is converted into drawing data, A step of generating an allowable error area in an area where a difference due to an arbitrary angle approximation is generated from an arbitrary angle graphic included in the design data, and a differential graphic including the coverage of the differential graphic and the height of the graphic in the allowable error area Of the area of the difference graphic when divided into two with the size of the region and an arbitrary angle oblique side of the area as a boundary, whether the difference graphic that becomes a defect is included in the allowable error area based on at least one calculation result A drawing data verification method comprising: determining whether or not.

Furthermore, a mask drawing apparatus according to another embodiment of the present invention includes an input unit for inputting design data,
A first logical operation unit that obtains a difference graphic by performing an exclusive OR operation between the design data and drawing data converted from the design data, and an arbitrary angle approximation from an arbitrary angle graphic included in the design data A tolerance error area generating unit that generates a figure corresponding to an allowable error area of an area where a difference occurs, and calculating a logical difference of a figure corresponding to the allowable error area from the difference graphic, And a second logical operation unit for obtaining the excluded difference graphic.

  According to the present invention, since the difference graphic resulting from the arbitrary angle approximation at the time of data conversion is removed, the conversion error can be verified with high accuracy.

(Embodiment 1)
FIG. 1 is a conceptual diagram illustrating an example of a system configuration according to the first embodiment.
As shown in FIG. 1, first, the layout of the semiconductor integrated circuit is designed. Then, CAD data (design data) 10 serving as layout data is generated. Then, the CAD data 10 is converted by the conversion device 20, and drawing data 12 to be input to the electron beam drawing device is generated. The drawing data 12 is data converted into an input format of an electron beam drawing apparatus that draws a graphic pattern on a sample using an electron beam. Examples of the sample include a reticle and a photomask. Based on the drawing data 12, the data is further converted into data in a format in the electron beam drawing apparatus and drawn. Then, the data verification apparatus 200 verifies whether the CAD data 10 and the drawing data 12 obtained by converting the CAD data 10 are the same. The data verification apparatus 200 includes a verification unit 100, a monitor 102, and an interface (I / F) circuit 104. Then, the verification unit 100 receives the CAD data 10 and the drawing data 12, performs an exclusive OR (XOR) operation, and detects a difference graphic resulting from the data conversion. Further, a logical difference operation is performed to remove a difference graphic corresponding to a region where a difference occurs due to arbitrary angle approximation. Then, the result data 14 is output to the outside via the I / F circuit 104. Alternatively, it is displayed on the monitor 102. By confirming the result data by the user, it is possible to verify the match or mismatch of the figures before and after conversion.

FIG. 2 is a conceptual diagram illustrating an example of an internal configuration of the data verification apparatus according to the first embodiment.
2, the verification unit 100 includes a CAD data distribution circuit 112, a drawing data distribution circuit 114, a memory 106, XOR operation circuits 122 and 124, and a mask processing circuit 130.

  First, as an input process, the verification unit 100 inputs CAD data 10. The input CAD data 10 is sent to the CAD data distribution circuit 112. On the other hand, the verification unit 100 inputs the drawing data 12 converted from the CAD data 10.

FIG. 3 is a diagram illustrating an example of a graphic included in the CAD data according to the first embodiment.
FIG. 3 shows CAD data 10 in which a triangular arbitrary-angle graphic 140 and a rectangular non-optional angular graphic 150 are mixed. Here, the arbitrary-angle figure 140 indicates a figure having an angle that cannot be formed by the forming aperture of the drawing apparatus. For example, in the case of a drawing apparatus having a forming aperture capable of forming angles of 45 degrees and 90 degrees, the arbitrary angle is an angle excluding an integer multiple of 45 degrees or 90 degrees.

FIG. 4 is a diagram illustrating an example of a graphic included in the converted drawing data according to the first embodiment.
Here, the drawing data 12 is shown in which a rectangular figure 160 which is a non-arbitrary figure and a divided figure group 170 obtained by slit-dividing an arbitrary figure are mixed. In this example, there is one rectangular non-arbitrary figure, but in practice, a figure group consisting of a plurality of figures is formed.

  Then, as shown in FIG. 2, the input drawing data 12 is sent to a drawing data distribution circuit 114. Here, data is directly input to each distribution circuit, but may be input via an I / F circuit.

Next, as a distribution step, the CAD data distribution circuit 112 distributes the graphic included in the CAD data 10 into an arbitrary angle graphic and a non-optional angle graphic.
The CAD data distribution circuit 112 creates a file 32 in which only an arbitrary angle figure is defined among the figures included in the CAD data 10 and stores the file 32 in the memory 106. Further, a file 42 in which only non-arbitrary-angle figures (rectangular figures) are defined is created and stored in the memory 106.

On the other hand, the drawing data distribution circuit 114 divides the figure included in the drawing data 12 into a figure group (slit division figure) corresponding to the above-mentioned arbitrary angle figure and a figure (rectangular figure) corresponding to the above-mentioned non-arbitrary figure. Distribute.

  FIG. 4 is a diagram showing a figure 160 corresponding to a non-arbitrary angle figure and a slit division figure 170 corresponding to an arbitrary angle figure. The drawing data distribution circuit 114 creates a file 44 in which only non-arbitrary-angle figures (rectangular figures) are defined and stores them in the memory 106. Further, the drawing data distribution circuit 114 creates the file 34 in which only the slit division figure group is defined and stores it in the memory 106.

  Next, as an XOR operation step, the XOR operation circuit 122 reads the data file 32 of the arbitrary angle graphic and the data file 34 of the slit divided graphic group from the memory 106. Then, an exclusive OR (XOR) operation is performed on the data of the arbitrary angle graphic included in the file 32 and the data of the slit divided graphic group included in the file 34. On the other hand, the XOR operation circuit 124 reads the non-arbitrary-angle graphic data file 42 and the non-arbitrary-angle corresponding graphic data file 44 from the memory 106. Then, an exclusive OR (XOR) operation is performed on the non-arbitrary angle graphic data included in the file 42 and the non-arbitrary angle corresponding graphic data included in the file 44.

FIG. 5 is a diagram illustrating an example of a calculation result of an arbitrary angle portion in the first embodiment. As shown in FIG. 5, a difference graphic (shaded part) 181 of a rectangular figure due to a conversion error and a difference graphic 182 (hatched part) of an arbitrary angle graphic group in which a difference due to arbitrary angle approximation occurs are output.
Next, as a step of creating a figure that covers an AED (Allowable Error Domain) area, the AED generation unit 126 reads an arbitrary-angle figure data file 32 from the memory 106 and includes it in the CAD data 10 shown in FIG. The coordinate data (position data) of the start point t1 (x1, y1) and the end point t2 (x2, y2) of the hypotenuse of the arbitrary angle figure 140 to be obtained is defined, and an arbitrary angle approximation value (ε value) is defined from the memory 106 A certain setting file 56 is read. Here, in the case of using a division method in which the midpoint of the approximate divided figure is on the oblique line of the arbitrary angle figure, and the maximum deviation between the oblique line and the approximate divided figure is an arbitrary angle approximate value (approximation accuracy) The figure covering the AED region can have an arbitrary angle approximate value of the width on one side. For example, as shown in FIG. 6, first, a reference line connecting the points is drawn from the acquired coordinate data of the points t1 and t2, and a line having an ε value as a width on both sides of the oblique line based on the acquired arbitrary angle approximate value. pull. Also, perpendicular lines are drawn from the start point t1 (x1, y1) and the end point t2 (x2, y2) in the X-axis and Y-axis directions, and the area surrounded by these lines is defined as an AED area, and this AED area Create a figure of the size you want.

  Next, as a step of removing the difference graphic in the AED area, the mask processing circuit 130 includes a difference graphic output from the XOR circuit 122 and a graphic corresponding to the AED area output from the AED generation unit 126 ( (Hereinafter referred to as AED graphic). As shown in FIG. 7, the mask processing circuit 130 performs a logical difference operation on the AED figure 202 corresponding to the AED area from the difference figure output from the XOR circuit 122, and removes the difference figure in the AED area. In other words, the mask processing circuit 130 performs a logical difference operation as “difference graphic” AND “AED graphic obtained by NOT operation” to realize (difference graphic-AED graphic). As a result, difference figures 191 and 192 as shown in FIG. 8 are obtained. The calculation result is output as result data 51 via an external interface (I / F).

Next, the processing flow in the first embodiment will be described with reference to FIG.
First, the layout of the semiconductor integrated circuit is designed. Then, CAD data (design data) serving as layout data is generated (step S1).

  The CAD data 10 is converted by the conversion device 20 to generate drawing data 12 to be input to the electron beam drawing device. (Step S2).

  In addition, a setting file of predetermined arbitrary angle approximation values (angle and ε value), which are parameters for creating an AED figure that covers an AED area, which will be described later, is stored in advance in a memory mounted on the verification unit 100 (step S3).

  The verification unit 100 receives the CAD data 10 and the drawing data 12, and performs an operation for obtaining an exclusive OR in the XOR operation circuit (step S4). By this calculation, a differential graphic due to a data conversion processing error and a differential graphic of a portion approximating an arbitrary angle are detected.

  Further, the AED generation unit creates an AED figure having a size corresponding to the AED area based on the arbitrary angle approximation as shown in FIG. 6 (step S5).

  Next, the difference graphic obtained by the exclusive OR (XOR) operation in step S4 is masked with the AED graphic, and the differential graphic in the AED area is removed. That is, the mask processing circuit 130 is used to perform an operation for obtaining the logical difference of the AED figure corresponding to the AED area from the difference figure, and the difference figure in the AED area is removed (step S6). The difference graphic by the logical difference calculation is obtained by removing the difference graphic due to the arbitrary angle approximation, and only the difference graphic due to the defect of the data conversion process remains as shown in FIG.

  Next, the difference graphic obtained by the logical difference calculation is output as result data 51 (step S7). The result data 51 is stored in the memory 14.

  In the description of the first embodiment described above, in the example of the data verification apparatus illustrated in FIG. 2, a rectangular figure and other arbitrary figure (or slit) using the CAD data distribution circuit 112 and the drawing data distribution circuit 114 are used. After the data is divided into (divided graphics), the CAD data and the drawing data are input to the XOR operation circuits 122 and 124 to perform the calculation, and the difference graphic between the CAD data and the drawing data is detected. However, the circuit configuration is limited to this. It is not a thing. For example, as a modification, the CAD data distribution circuit 112 and the drawing data distribution circuit 114 are omitted, and the CAD data 10 and the drawing data 12 are directly input to the XOR operation circuits 122 and 124 to detect the difference graphic. There may be. That is, the CAD data 10 shown in FIG. 3 and the drawing data 12 shown in FIG. 4 are input to the XOR operation circuit without being divided into arbitrary-angle graphics and other graphics (rectangular or slit-divided graphics). Then, the difference graphic is detected by the XOR operation circuit.

  Further, by calculating the logical difference of the AED figure from the difference figure obtained by the XOR operation and removing the difference figure in the AED area, the difference figure due to the defect of the data conversion process can be detected.

  As described above, in the first embodiment, the portion that approximates an arbitrary angle, that is, the difference graphic in the allowable area in the arbitrary angle approximation portion is removed by the AED graphic. And data verification can be performed with high accuracy.

(Embodiment 2)
In the first embodiment described above, an AED figure of a size corresponding to the AED area is created based on one arbitrary approximate value regardless of the angle of the arbitrary angle. However, in this embodiment, as shown in FIG. An AED figure is created using the setting file 56 in which an arbitrary angle approximation value (ε value) is described for each arbitrary angle.

  FIG. 11 shows a processing flow in the second embodiment, which will be described with reference to FIG. First, the layout of the semiconductor integrated circuit is designed. Then, CAD data (design data) serving as layout data is generated (step S1).

The CAD data 10 is converted by the conversion device 20 to generate drawing data 12 to be input to the electron beam drawing device. (Step S2).
Further, as shown in FIG. 10, a setting file 56 in which an arbitrary angle approximation value (angle and ε value) serving as a parameter for creating an AED figure covering the AED area is described is stored in the memory 106 (step S13). ).

The verification unit 100 receives the CAD data 10 and the drawing data 12, and performs an operation for obtaining an exclusive OR in the XOR operation circuit (step S4). By this calculation, a differential graphic due to a data conversion processing error and a differential graphic of a portion approximating an arbitrary angle are detected.

  The AED generation unit 126 reads an arbitrary angle approximation value (angle, ε value) described in the setting file as shown in FIG. 11, and creates an AED figure that covers the AED area based on the read value (step S5).

  The AED area is an area where a difference caused by an arbitrary angle approximation portion predicted from an arbitrary angle approximation algorithm is detected from an arbitrary figure of design data. In the setting file 56, an ε value corresponding to an arbitrary angle is described. For example, when creating a slit division figure of drawing data using a division algorithm in which an arbitrary angle approximation value varies depending on an arbitrary angle angle, The AED figure shown in FIG. 6 is created based on the approximate value of the angle (ε value). When there are a plurality of arbitrary angles in the CAD data 10, the AED graphic shown in FIG. 6 is created for each arbitrary angle graphic having different angles.

  Next, using the mask processing circuit 130, a logical difference operation is performed to remove the difference graphic in the AED area from the difference graphic. By this calculation, a difference graphic due to a defect is detected (step S6). This difference graphic is obtained by removing the difference graphic due to the arbitrary angle approximation, and is only the difference graphic due to the defect of the data conversion process. Here, when the difference graphic is removed, the verification accuracy can be improved because the AED graphic shown in FIG. 6 is created according to the angle of a different arbitrary graphic. In the example shown in FIG. 10, the arbitrary angle approximate value definition file does not have an ε value when the angle is 45 degrees. This is because the electron beam drawing apparatus has a shaping aperture capable of forming an angle of 45 degrees.

Next, the difference graphic obtained by the logical difference calculation is output as result data 51 (step S7). The result data 51 is stored in the memory 14.
As described above, in the second embodiment, since an arbitrary angle approximate value described for each angle is read from the setting file to create an AED graphic, the AED graphic is generated according to the angle of the arbitrary angular graphic. Therefore, data verification can be performed with high accuracy.

(Embodiment 3)
In the first and second embodiments, a difference graphic due to a defect in the AED area cannot be detected. Therefore, a verification method for a case where data verification inside the AED area is necessary will be described.

As shown in FIG. 12, when the AED area includes an extra figure generated due to a data conversion error or a finely divided figure, these defects cannot be detected. Therefore, when verification inside the AED is necessary, verification is performed using the following method.
First, in the example shown in FIG. 13, the area of the difference graphic in the AED region is calculated, and the presence or absence of a defect is verified based on the coverage value for the AED region.

  The pattern coverage of a normal differential figure in the AED area can be predicted as 2/7 + 2/8 × n + 2/7. Here, n is the number of slit divisions excluding both ends of the AED region, and n = (slit division number−2). When the pattern coverage ratio of the drawing data is calculated and the value of the coverage ratio deviates from the predicted value, an unintended pattern in the AED area, for example, an extra figure generated by data conversion as shown in FIG. It is determined that there is a high possibility that a fine divided figure or the like has occurred.

  Next, in the example shown in FIG. 14, the quality of a graphic is determined by measuring whether or not one side of the graphic is a diagonal line or the height from the diagonal line for all the differential graphics in the AED area. In FIG. 14, the second graphic from the left has no diagonal lines, and is an extra graphic generated due to a conversion error, and is determined to be an abnormal graphic. The first, third to fifth from the left have diagonal lines, but the height is measured to determine whether it is normal. In this example, as a result of the height measurement, it is determined that the first and third satisfy a predetermined value and are normal.

  Further, in the example shown in FIG. 15, the AED area is divided into two areas with a hypotenuse of an arbitrary angle as a boundary, and the area sum of the difference graphic in each area is obtained. For example, the difference graphic of the AED area A1 on the upper left side is added as a plus to obtain the total area. On the other hand, the difference graphic of the AED area A2 on the lower right side is negative, and the total area (A1 + A2) is obtained, and the sum of the entire AED area is obtained. If the result is close to 0 (within the allowable range), it is determined as normal, and if it exceeds the allowable range, it is determined as a malfunction.

  As described above, in the third embodiment, since it is possible to determine whether or not there is a defect in the difference graphic in the AED area, highly accurate verification can be performed.

  In the above description, what is described as “˜circuit”, “˜part”, or “˜process” can be configured by a computer operable program. Moreover, you may implement | achieve not the program used as software but the combination with hardware or firmware.

  In the drawing data verification method, each process of the drawing data verification method can be realized by reading a program recorded in a recording medium into a computer and controlling the operation by the program. Examples of the recording medium include storage devices such as a magnetic disk device, an optical disk device (CD-ROM, DVD, etc.), and a semiconductor memory.

  The embodiments of the present invention have been described above. However, the present invention is not limited to these specific examples, and components can be modified and embodied without departing from the gist of the present invention in the implementation stage.

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

1 is a conceptual diagram illustrating an example of a system configuration in a first embodiment. 3 is a conceptual diagram illustrating an example of an internal configuration of a data verification device according to Embodiment 1. FIG. 6 is a diagram illustrating an example of a graphic included in CAD data according to Embodiment 1. FIG. It is a figure which shows an example of the figure which converted CAD data of FIG. 3 into drawing data. It is a figure which shows the difference figure of CAD data and drawing data. It is a figure which shows an example of figure creation corresponding to an AED area | region. It is a figure which shows an example of the figure masked by the AED figure with respect to the difference figure which carried out XOR calculation. It is a figure which shows an example of the figure which removed the difference figure in the AED area | region with respect to the difference figure which carried out XOR calculation. 5 is a diagram illustrating an example of a processing flow in the first embodiment. FIG. It is a figure which shows an example of the setting file in which the arbitrary angle | corner approximate value was described. It is a figure which shows an example of the processing flow in Embodiment 2. FIG. It is a figure which shows an example of the difference figure inside an AED area | region. It is a figure which shows an example which calculates the coverage of the difference figure in an AED area | region. It is a figure which shows an example which measures the height of the difference figure in an AED area | region. It is a figure which shows an example which calculates the area of the area | region which divided the difference figure in an AED area | region into two. It is a figure which shows an example of the XOR verification result before and behind the conventional data conversion. It is a figure which shows an example of the arbitrary angle figures of the conventional CAD data and the converted drawing data. It is a figure which shows an example of the XOR verification result before and after the drawing data conversion in the conventional arbitrary angle figures. It is a figure which shows an example of the XOR verification result before and after the drawing data conversion containing the conventional arbitrary angle figures.

Explanation of symbols

10 CAD data 12 Drawing data 14, 51, 53 Result data 20 Conversion device 32, 34, 42, 44, 56 File 100 Verification unit 102 Monitor 104 I / F circuit 106 Memory 112 CAD data sorting circuit 114 Drawing data sorting circuit 126 AED generator 130 Mask processing circuit

Claims (5)

A step of obtaining a difference graphic between the design data and drawing data converted from the design data;
When converting design data into drawing data, generating a graphic corresponding to an allowable error region of a region where a difference due to arbitrary angle approximation occurs from an arbitrary angle graphic included in the design data;
A step of subtracting a graphic corresponding to the allowable error area from the differential graphic to remove the differential graphic in the allowable error area;
A drawing data verification method characterized by comprising: The drawing data verification method according to claim 1, wherein the figure corresponding to the allowable error area is generated based on a predetermined arbitrary angle approximate value.   The drawing data verification method according to claim 1, wherein the figure corresponding to the allowable error region is generated based on an arbitrary angle approximation value corresponding to an arbitrary angle. A step of obtaining a difference graphic between the design data and drawing data converted from the design data;
When converting design data into drawing data, generating an allowable error region of a region in which a difference due to arbitrary angle approximation occurs from an arbitrary angle graphic included in the design data;
At least one of the coverage of the differential graphic in the allowable error region, the size of the differential graphic including the height of the graphic, and the area difference of the differential graphic when divided into two with an arbitrary angle oblique side of the region as a boundary And a step of determining whether or not a difference graphic that becomes a defect is included in the allowable error region based on a calculation result. An input unit for inputting design data;
A first logical operation unit that obtains a differential graphic by performing an exclusive OR operation on the design data and drawing data converted from the design data;
An allowable error region generating unit for generating a graphic corresponding to an allowable error region of a region where a difference due to arbitrary angle approximation occurs from an arbitrary angle graphic included in the design data;
Performing a calculation to obtain a logical difference of a graphic corresponding to the allowable error area from the differential graphic, a second logical calculation unit to obtain a differential graphic excluding the allowable error area;
A mask drawing apparatus comprising: