JP2013045372A - Image evaluation method, drawing condition selection method, image evaluation program, and drawing condition selection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image evaluation method and an image evaluation program that enable accurate and easy evaluation of a mask pattern drawn on a mask, and provide a drawing condition selection method and a drawing condition selection program for calculating a drawing condition under which a desired figure can be drawn.SOLUTION: In an image evaluation method and an image evaluation program, it is determined whether the areas of a reference figure and a drawn figure are the same or almost the same, it is determined whether approximate shapes of both figures are similar using a reference figure long/short ratio and a drawn figure long/short ratio as length ratios between first principal components and second principal components obtained by performing principal component analysis on point sequences calculated from contour lines of both figures, and when it is determined that the approximate shapes of the reference figure and the drawn figure are similar and their areas are the same, it is determined that the reference figure matches the drawn figure.

Description

  The present invention relates to an image evaluation method, a drawing condition selection method, an image evaluation program, and a drawing condition selection program.

Conventionally, various evaluations for evaluating whether or not a mask pattern has been created in a desired shape using an SEM (Scanning Electron Microscope) image of the mask pattern drawn with an electron beam or the like on the mask The method is known.
For example, when the figure of the mask pattern to be measured is a figure having a parallel line part in the contour line such as a line-like figure having a predetermined width, the line width of the parallel line part is set to It is possible to evaluate the image by measuring the length. In the case of such a line width measurement, there is a method in which several tens to several hundreds of line widths are measured at predetermined intervals, and an average value thereof is taken for evaluation. For example, when the figure of the mask pattern to be measured is a figure having a parallel line part in the contour line such as a line-like figure having a predetermined width, the line width of the parallel line part is set to It is possible to evaluate the image by measuring the length. In general, SEM images often contain a lot of undesirable noise, and the measurement result of the line width along one section shows an unstable value depending on this noise. Low reliability. In the case of the measurement of the line width of the parallel lines as described above, the influence of noise is reduced by measuring the line widths of several tens to several hundreds at predetermined intervals and evaluating the average values. There is a way to do it.

However, the figure shape of the mask pattern is further miniaturized due to the miniaturization of wiring and the like accompanying the recent high integration. Therefore, the roundness of the corner portion of the mask pattern becomes large, the influence of the rounded portion becomes relatively large, and the parallel line portion to which the above method can be applied becomes small. In some cases, the mask pattern has a substantially circular shape, and there is only one longest portion of the diameter, so that the above measurement method cannot be applied.
Furthermore, with the miniaturization of elements and wirings, circuit patterns are formed using optical proximity correction (OPC) technology, so that the roundness of the corners of the mask pattern becomes larger.

Further, as one of the methods for evaluating whether or not a desired figure is drawn as a mask pattern, the area of the figure, the ratio of the major axis to the minor axis, and the like are used as index values, and the evaluation target of the SEM image of the mask pattern is used. There is an evaluation method in which a figure and a figure in design data are compared and evaluated using this index value (for example, Patent Document 1).
However, when such an evaluation method is used, even if the figure of the mask pattern is greatly deformed compared to the design figure, if the area and the ratio of the major axis to the minor axis are the same, the difference is There was a problem that it was not detected and it was evaluated that a preferable shape was drawn.

Japanese Patent No. 4593236

An object of the present invention is to provide an image evaluation method and an image evaluation program capable of easily evaluating a mask pattern drawn on a mask with higher accuracy.
Another object of the present invention is to provide a drawing condition selection method and a drawing condition selection program for easily selecting a drawing condition capable of drawing a desired figure.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is an image evaluation method for comparing a drawn figure (1b) drawn on a photomask (40) with a reference figure (1a) which is a reference for comparison of the drawn figure. The first principal component and the second principal component obtained by principal component analysis of the area of the figure, and the outline (2a) of the reference figure, and the length and second of the first principal component of the outline of the reference figure A reference graphic data storing step (S11) for storing data relating to a reference graphic length / short ratio (RA) which is a ratio of the lengths of the principal components; A drawing figure area calculating step (S121 to S123) to be calculated, image processing is performed on imaging data of the drawing figure, and a contour component of the drawing figure is subjected to principal component analysis to calculate a first principal component and a second principal component. The length of the first principal component of the contour line of the drawing figure And a drawing figure length / shortness ratio calculating step (S124 to A126) for calculating a drawing figure length / shortness ratio which is a ratio of the lengths of the second principal components, the area of the reference figure stored in the reference figure data storage step, and the drawing An area comparison step (S131) for comparing the areas of the drawn figures calculated in the figure area calculation step to determine whether or not they are the same or substantially the same, and the reference figure length short and long stored in the reference figure data storage step The approximate similarity determination step of determining whether the reference graphic and the outline of the drawing figure are similar based on the ratio of the ratio and the drawing figure length / shortness ratio calculated in the drawing figure length / short ratio calculation step (S132) and a graphic determination step (S13) for determining whether or not the reference graphic and the drawing graphic match based on the results of the area comparison step and the approximate similarity determination step, the graphic determination If it is determined in the approximate similarity determination step that the reference graphic and the rough shape of the drawing graphic are similar, and in the area comparison step, the area of the reference graphic and the area of the drawing graphic are the same. When it is determined that there is a match, the reference graphic and the drawing graphic are determined to match, and when the rough similarity determination step determines that the reference graphic and the drawing graphic are not similar, and the area In the comparison step, when it is determined that the area of the reference graphic and the area of the drawing graphic are not the same, it is determined that the reference graphic and the drawing graphic do not match. This is an image evaluation method.

According to a second aspect of the present invention, in the image evaluation method according to the first aspect, the orientation of the axis of the first principal component of the reference graphic (1a) stored in the reference graphic data storage step (S11), and the drawing graphic By comparing the orientation of the axis of the first principal component of the drawing figure (1b) calculated in the long / short ratio calculation step (S124 to S126), it is determined whether or not the directions of the reference figure and drawing figure match. An inclination determination step (S134), and when the graphic determination step (S13) determines that the area of the reference graphic and the area of the drawing graphic are the same in the area comparison step, and the rough shape When it is determined in the similarity determination step that the rough shape of the reference graphic and the drawing graphic is similar, and when the inclination determination step determines that the orientations of the reference graphic and the drawing graphic match, the reference graphic And said When it is determined that the drawing figures match and the area comparison step determines that the area of the reference figure and the area of the drawing figure are not the same, the outline of the reference figure and the drawing figure in the outline similarity determination step Is determined to be not similar, in at least one case where it is determined in the tilt determination step that the orientations of the reference figure and the drawing figure do not match, the reference figure and the drawing figure do not match. An image evaluation method characterized by determining.
According to a third aspect of the present invention, in the image evaluation method according to the second aspect, an inclination determination necessity determination step (S133) for determining whether or not the reference graphic (1a) and the drawing graphic (1b) are circular. And when the inclination determination necessity determination step determines that both the reference graphic and the drawing graphic are not circular, the inclination determination step (S134) is performed, and the determination necessity determination step An image evaluation method characterized by not performing the inclination determination step when it is determined that either a reference graphic or the drawing graphic is circular.

According to a fourth aspect of the present invention, in the image evaluation method according to any one of the first to third aspects, the reference graphic (1a) is drawn in advance on a photomask (40) as the comparison reference. This is an image evaluation method characterized by being a figure on imaging data obtained by imaging a drawn figure.
According to a fifth aspect of the present invention, in the image evaluation method according to any one of the first to third aspects, the reference figure (1a) is formed on a photomask using design data as the comparison reference. An image evaluation method characterized by being a figure obtained by a simulation for drawing.
The invention of claim 6 is the image evaluation method according to any one of claims 1 to 5, wherein the drawing figure length-to-short ratio calculating step (S124 to S126) is an outline of the drawing figure (1b). A point sequence calculation step (S124) for calculating the point sequence (3b) constituting the line (2b), a covariance matrix is calculated by performing principal component analysis on the point sequence calculated in the point sequence calculation step, and this covariance matrix is calculated. The eigenvalues λ1 and λ2 (where λ1 ≧ λ2) of the first principal component and the second principal component of the drawing figure obtained by eigenvalue decomposition of the variance matrix are calculated, and the two eigenvalues λ1 and λ2 are calculated. An eigenvalue ratio calculating step (S125, S126) for calculating a square root of the ratio λ1 / λ2 (λ1 / λ2) ^1/2 as the drawing figure length / shortness ratio.

  The invention of claim 7 is an image evaluation program for comparing a drawing figure (1b) drawn on a photomask with a reference figure (1b) which is a reference for comparison of the drawing figure, wherein the computer The first principal component and the second principal component obtained by principal component analysis of the area of the figure, the outline of the reference figure, the length of the first principal component and the second principal component of the outline of the reference figure Reference graphic data storage means for storing data related to a reference graphic length / short ratio, which is a ratio of lengths, image processing of image data of the drawing figures, and drawing graphic area calculation means for calculating the area of the drawing figures; The imaging data of the drawing figure is subjected to image processing, the outline of the drawing figure is subjected to principal component analysis to calculate the first principal component and the second principal component, and the length of the first principal component of the outline of the drawing figure is calculated. Drawing which is the ratio of the length of the second principal component The drawing figure length / shortness ratio calculating means for calculating the shape length / shortness ratio, the area of the reference figure stored in the reference figure data storage means, and the area of the drawing figure calculated by the drawing figure area calculating means are the same Based on the ratio of the area comparison means for determining whether or not, the reference figure length / short ratio stored in the reference figure data storage means, and the drawing figure length / short ratio calculated by the drawing figure length / short ratio calculation means , Functioning as outline similarity determining means for determining whether or not the reference figure and the drawn figure are similar, and as figure determining means for determining whether or not the reference figure and the drawn figure match. The figure determining means determines that the outline similarity determining means determines that the outline of the reference figure and the drawing figure are similar, and the area comparing means determines the area of the reference figure and the drawing figure. When it is determined that the areas are the same, it is determined that the reference figure and the drawing figure match, and the outline similarity determination unit determines that the outline of the reference figure and the drawing figure are not similar. And the area comparison means functions to determine that the reference graphic and the drawing graphic do not match in at least one case where the area of the reference graphic and the area of the drawing graphic are determined not to be the same. An image evaluation program characterized by

According to an eighth aspect of the present invention, in the image evaluation program according to the seventh aspect, the computer is arranged such that the orientation of the axis of the first principal component of the reference graphic (1a) stored in the reference graphic data storage means and the drawing Inclination determination means for comparing the orientation of the axis of the first principal component of the drawn figure (1b) calculated by the figure length / short ratio calculating means to determine whether or not the directions of the reference figure and the drawn figure match. And when the rough shape determination means determines that the rough shape of the reference graphic and the drawing graphic is similar, and the directions of the reference graphic and the drawing graphic match. And when the area comparison means determines that the area of the reference graphic and the area of the drawing graphic are the same, it determines that the reference graphic and the drawing graphic match, and When the determining means determines that the rough shapes of the reference graphic and the drawing graphic are not similar, when it is determined that the orientations of the reference graphic and the drawing graphic do not match, and the area comparing means is the area of the reference graphic And at least one of the cases where it is determined that the areas of the drawing figures are not the same, a function for determining that the reference figure and the drawing figure do not coincide with each other. is there.
According to a ninth aspect of the present invention, in the image evaluation program according to the eighth aspect, the computer is used to determine whether the reference graphic (1a) and the drawn graphic (1b) are circular. When the inclination determination necessity determination means determines that the reference graphic and the drawing graphic are neither circular or substantially circular, the inclination determination means determines that the inclination determination necessity determination function determines whether the inclination determination necessity determination means determines that the reference graphic and the drawing It is determined whether or not the outline of the figure is similar, and when it is determined that either the reference figure or the drawing figure is a circle or a substantially circle, the inclination determination unit determines whether the reference figure and the drawing figure are An image evaluation program characterized in that it functions so as not to determine whether or not the directions coincide.

A tenth aspect of the present invention is the image evaluation program according to any one of the seventh to ninth aspects, wherein the drawing figure length / shortness ratio calculating means calculates a sequence of points constituting the outline of the drawing figure. And a first co-variance matrix obtained by performing principal component analysis on the point sequence calculated by the point sequence calculation unit and eigenvalue decomposition of the covariance matrix. Eigenvalues λ1 and λ2 (where λ1 ≧ λ2) of the principal component and the second principal component are calculated, and the square root (λ1 / λ2) ^1/2 of the ratio λ1 / λ2 of the two eigenvalues λ1 and λ2 is drawn. An image evaluation program that functions as an eigenvalue ratio calculation unit that calculates a figure length / shortness ratio.

  The eleventh aspect of the present invention is that, among the conditions for drawing a drawing figure (1b) equal to the reference figure (1a) on the photomask (40), the outline of the drawing figure is similar to the outline of the reference figure A drawing condition selection method that selects a rough shape similarity condition that is a condition that affects whether or not, and an area condition that affects the area of the drawing graphic while maintaining the similarity of the rough shape with the reference graphic, The first principal component and the second principal component obtained by principal component analysis of the area of the reference graphic, the outline of the reference graphic, the length of the first principal component and the second main component of the outline of the reference graphic A reference graphic data storage step (S41) for storing data relating to a reference graphic length / shortness ratio, which is a ratio of component lengths, a plurality of the approximate shape similarity conditions are set, a plurality of drawing figures are drawn, and the plurality of drawing figures are drawn. The plurality of drawing diagrams are obtained by performing image processing on imaging data of a drawing figure. A principal component analysis of each contour line is performed to calculate the first principal component and the second principal component, and the ratio of the lengths of the first principal component and the second principal component of the contour lines of the plurality of drawing figures In the drawing figure length / shortness ratio calculating step (S42) for calculating the drawing figure length / shortness ratio of the plurality of drawing figures, the reference figure length / shortness ratio stored in the reference figure data storage step, and the drawing figure length / shortness ratio calculating step A rough similarity determination step (S43) for determining whether or not the rough shapes of the reference graphic and the plurality of drawing figures are similar based on the ratio of the calculated drawing figures to the drawing figure length / shortness ratio; The drawing figure length / shortness ratio calculating step and the approximate shape similarity determining step are used to select a condition in which the outline of the drawn figure is most similar to the outline of the reference figure from among the plurality of outline similarity conditions. Shape-similar condition selection step (S44) and the outline shapes The outline similarity condition selected in the condition selection step is set, the plurality of area conditions are set, a plurality of drawing figures are drawn, the imaging data of the plurality of drawing figures is subjected to image processing, and the plurality of drawing A drawing figure area calculating step (S45) for calculating the area of the figure, the area of the reference figure stored in the reference figure data storing step, and the areas of the plurality of drawing figures calculated in the drawing figure area calculating step. By comparing the area comparison step (S46) for determining whether or not they are the same, the drawing figure area calculation step, and the area comparison step, the area of the drawing figure becomes the area of the reference figure most. An area condition selection step (S47) for selecting near conditions, the combination of the approximate shape similarity condition selected in the approximate shape similarity condition selection step, and the area condition selected in the area condition selection step is the optimum condition. A drawing condition selection step (S48) for selecting as a matter.

A twelfth aspect of the present invention is the drawing condition selecting method according to the eleventh aspect, wherein a backscattering parameter amount is selected as the approximate shape similarity condition.
A thirteenth aspect of the present invention is the drawing condition selecting method according to the eleventh or twelfth aspect, wherein the dose amount is selected as the area condition.
The invention according to claim 14 is the drawing condition selection method according to any one of claims 11 to 13, wherein the approximate similarity condition selection step includes the reference graphic after the approximate similarity determination step. Comparing the orientation of the axis of the first principal component of the reference figure stored in the data storage step with the orientation of the axis of the first principal component of the plurality of drawing figures calculated in the drawing figure length / shortness ratio calculating step; An inclination determination step is performed to determine whether or not inclinations of the reference graphic and the plurality of drawing figures match, and the plurality of outline similarity conditions are based on the results of the outline similarity determination step and the inclination determination step. A drawing condition selection method characterized by selecting a condition in which the outline of the drawing figure is most similar to the outline of the reference figure.

  In the invention of claim 15, the rough shape of the drawn graphic is similar to the rough shape of the reference graphic among the conditions for drawing the drawn graphic (1b) equal to the reference graphic (1a) on the photomask (40). A drawing condition selection program that selects a rough shape similarity condition that is a condition that affects whether or not, and an area condition that affects the area of the drawing graphic while maintaining the similarity of the rough shape with the reference graphic, A first principal component and a second principal component obtained by principal component analysis of the area of the reference graphic, the contour line of the reference graphic, the length of the first principal component of the contour line of the reference graphic, and A reference figure data storage means for storing data relating to a reference figure length / shortness ratio, which is a ratio of the lengths of the second principal components, and a plurality of outline similar conditions are set to draw a plurality of drawing figures; The image data of the drawing figure is processed, A principal component analysis is performed on the contour lines of a plurality of drawing figures to calculate respective first principal components and second principal components, and the lengths of the first principal component and the second principal component of the contour lines of the plurality of drawing figures are calculated. A drawing figure length / shortness ratio calculating means for calculating a drawing figure length / shortness ratio of the plurality of drawing figures as a ratio of lengths, the reference figure length / shortness ratio stored in the reference figure data storage means, and the drawing figure length / shortness ratio calculating means Based on the ratio of the drawing figure length / shortness ratio of the plurality of drawing figures calculated to determine whether the reference figure and the plurality of drawing figures are similar or not, By performing the drawing figure length / shortness ratio calculating means and the outline similarity determination means, the condition that the outline of the drawing figure is most similar to the outline of the reference figure is selected from the plurality of outline similarity conditions And the approximate similarity condition selection means, and the approximate similarity condition The outline similarity condition selected by the selection means is set, a plurality of area conditions are set, a plurality of drawing figures are drawn, imaging data of the plurality of drawing figures is subjected to image processing, and the plurality of drawing figures The drawing figure area calculating means for calculating the area of the reference figure, the area of the reference figure stored in the reference figure data storage means, and the areas of the plurality of drawing figures issued by the drawing figure area calculating means are the same An area condition for selecting a condition in which the area of the drawing figure is closest to the area of the reference figure by performing the area comparison means for determining whether or not the drawing figure area calculation means and the area comparison means As a drawing condition selection means for selecting, as an optimum condition, a combination of a selection means, the outline similarity condition selected by the outline similarity condition selection means, and the area condition selected by the area condition selection means This is a drawing condition selection program characterized by functioning.

According to the present invention, the following effects can be obtained.
According to the present invention, it is possible to provide an image evaluation method and an image evaluation program capable of easily evaluating a mask pattern drawn on a mask with higher accuracy.
In addition, according to the present invention, it is possible to provide a drawing condition selection method and a drawing condition selection program for calculating drawing conditions capable of drawing a desired figure.

It is a figure explaining the structure of the image evaluation system 1 of 1st Embodiment. It is a figure explaining the evaluation method of a drawing figure. It is a flowchart of the evaluation method of the drawing figure of 1st Embodiment. It is a flowchart which shows the process which memorize | stores the various information of a reference | standard figure and a drawing figure. It is a flowchart of the figure determination process of 1st Embodiment. It is a figure which shows the example of the reference | standard figure 1a and the drawing figure 1b. It is a figure which shows the example of the reference | standard figure 1a and the drawing figure 1b. It is a flowchart of the figure determination process of 2nd Embodiment. It is a figure explaining the arrangement | positioning data. It is a figure explaining the image evaluation system 3 of 3rd Embodiment. It is a flowchart of the drawing condition selection method of 3rd Embodiment. Drawing figures (for each drawing condition) drawn under the drawing conditions (B1-1, B2-1, B3-1) that are different from the reference figure (20 pieces) drawn under the drawing conditions (condition A). 20). Drawing figures drawn under drawing conditions (B1-1, B1-2, B1-3) that are different from the reference figures (20 pieces) drawn under the drawing conditions (condition A) (20 pieces for each drawing condition) FIG.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.

(First embodiment)
FIG. 1 is a diagram illustrating the configuration of an image evaluation system 1 according to the first embodiment.
The image evaluation system 1 of this embodiment includes a drawing device 10, an imaging device 20, an evaluation device 30, and the like. The drawing device 10, the imaging device 20, and the evaluation device 30 are connected to each other via a communication network such as a LAN or the Internet, and can transmit and receive information to and from each other. The image evaluation system 1 includes a reference figure of reference figure data serving as a reference for evaluation, and a drawing figure of SEM image data (drawing data) obtained by imaging the mask pattern 50 drawn on the photomask 40 by the drawing apparatus 10. It can be evaluated and whether or not a desired shape is drawn can be evaluated.

The drawing apparatus 10 is an electron beam drawing apparatus that draws a mask pattern on the photomask 40. The drawing apparatus 10 draws a mask pattern 50 based on input design data (not shown).
The imaging device 20 is a scanning electron microscope (SEM) that images the mask pattern 50 drawn on the photomask 40. The imaging device 20 can image a mask pattern 50 at a predetermined position on the photomask 40.

The evaluation device 30 is a device that compares and evaluates the shape and size of an image (SEM image) captured by the imaging device 20 and a reference graphic (reference graphic). The evaluation device 30 includes an evaluation device operation unit 31, an evaluation device display unit 32, an evaluation device transmission / reception unit 33, an evaluation device storage unit 34, an evaluation device control unit 35, and the like.
In the present invention, a computer refers to an information processing apparatus including a storage device, a control device, and the like. The evaluation device 30 is an information processing device including an evaluation device storage unit 34 and an evaluation device control unit 35, and is included in the concept of the computer of the present invention.

The evaluation device operation unit 31 is an operation device such as a keyboard and a mouse for the user to operate the evaluation device 30 and an input device.
The evaluation device display unit 32 is a monitor that displays an SEM image (drawing figure) and a comparison result between the reference figure and the drawing figure.
The evaluation device transmission / reception unit 33 is a part that transmits / receives information to / from the drawing device 10, the imaging device 20, and the like. For example, the SEM image of the design data input to the drawing device 10 and the mask pattern captured by the imaging device 20. Data is received and acquired via a communication network, or evaluation results are appropriately output to an external device.

The evaluation device storage unit 34 is a storage device such as a hard disk or a semiconductor memory element for storing programs, information, and the like necessary for the operation of the evaluation device 30.
The evaluation device storage unit 34 includes an evaluation program 34a, a reference graphic information storage unit 34b, and a drawing graphic information storage unit 34c.
The evaluation program 34a is a program for comparing the shape and size of the reference graphic of the reference graphic image data with the shape and size of the drawing graphic of the drawing graphic image data. The evaluation program 34a has an evaluation table in which various numerical values used for evaluating the drawing figure are stored.
The reference graphic information storage unit 34b is a storage area for storing reference graphic image data of a reference graphic serving as a reference for evaluating a drawing graphic and information related to the reference graphic.
The drawing graphic information storage unit 34c is a storage area for storing drawing graphic image data of the mask pattern 50 imaged by the imaging device 20 and information related to the drawing graphic.

The evaluation device control unit 35 is a control unit for comprehensively controlling the evaluation device 30, and includes, for example, a CPU (Central Processing Unit). The evaluation device control unit 35 reads out and executes various programs stored in the evaluation device storage unit 34 as appropriate, thereby realizing various functions according to the present invention in cooperation with the hardware described above.
The evaluation device control unit 35 includes an image processing unit 36, a graphic determination unit 37, and the like.

The image processing unit 36 is a part that performs various types of image processing on the image data of the reference graphic and the drawing graphic (such as SEM image data of the mask pattern drawn on the photomask 40).
The image processing unit 36 includes an outline extraction unit 36a, an area calculation unit 36b, a point sequence calculation unit 36c, a principal component analysis unit 36d, a long / short ratio calculation unit 36e, and an angle calculation unit 36f.
The contour line extraction unit 36a is a part that performs image processing on the image data of the reference graphic and the drawing graphic and extracts the contour lines of the reference graphic and the drawing graphic.
The area calculation unit 36b is a part that calculates the area within the outline of the reference graphic and the drawing graphic by a predetermined method.
The point sequence calculation unit 36c is a portion that calculates the reference graphic and the contour line of the drawing graphic extracted by the contour extraction unit 36a as a set of points on the xy coordinates (point sequence).

The principal component analysis unit 36d is a part that performs principal component analysis on the point sequence constituting the outline of the reference graphic and the drawing graphic calculated by the point sequence calculation unit 36c and calculates the first principal component and the second principal component. is there.
The length-to-short ratio calculating unit 36e has a length-to-short ratio (reference figure length-to-short ratio, drawing figure length-to-short ratio) that is a ratio of the length of the first principal component and the length of the second principal component of the contour line for the reference figure and the drawing figure, respectively. ).
The angle calculation unit 36f is a part that calculates an angle formed by the eigenvector of the first principal component of the reference graphic and the drawing graphic and the x axis.

The graphic determination unit 37 includes an area comparison unit 37a, an approximate shape determination unit 37b, an inclination determination necessity determination unit 37c, and an inclination determination unit 37d. The graphic determination unit 37 is a part that determines whether or not the reference graphic matches the drawing graphic.
The area comparison unit 37a compares the area of the reference graphic calculated by the area calculation unit 36b with the area of the drawing graphic to determine whether or not they are the same (including cases where they are substantially the same and can be regarded as the same). It is a part to judge.

The approximate shape determination unit 37b determines whether or not the shapes (rough shapes) of the reference graphic and the drawn graphic are similar based on the ratio between the reference graphic length / short ratio calculated by the long / short ratio calculating unit 36e and the drawn graphic length / short ratio. This is a part for determining.
Whether or not the inclination determination necessity determination unit 37c performs the inclination determination step by the inclination determination unit 37d based on whether or not the reference graphic and the drawing graphic are circular (including a case where the reference graphic and the drawing graphic are substantially circular). It is a part to determine whether.
The inclination determination unit 37d compares the orientation of the first principal component axis of the reference graphic and the orientation of the first principal component axis of the drawing graphic with the angle calculated by the angle calculation unit 36f, thereby comparing the reference graphic and the drawing. This is a part for determining whether the inclinations of the figures match.

  The graphic determination unit 37 determines whether the reference graphic matches the drawing graphic based on the result of the approximate similarity determination by the approximate shape determination unit 37b and the result of the area comparison by the area comparison unit 37a. When the inclination determination step is performed, the graphic determination unit 37 determines the inclination determination step of the inclination determination unit 37d as a result of the approximate similarity determination of the approximate similarity determination unit 37b and the area comparison of the area comparison unit 37a. Based on the result, it is determined whether or not the reference graphic matches the drawing graphic.

As shown below, the evaluation device 30 compares the reference graphic and the drawing graphic, and evaluates the shape and size of the drawing graphic.
FIG. 2 is a diagram for explaining a drawing graphic evaluation method.
FIG. 3 is a flowchart of the drawing graphic evaluation method of the first embodiment.
FIGS. 2A and 2B show images of the reference graphic and the drawing graphic, and FIGS. 2C and 2D show dot sequences of the reference graphic and the drawing graphic, respectively. In addition, the main component axes are shown.
The reference graphic image data DA is image data of a reference graphic serving as a reference for graphic evaluation. As the reference graphic image data DA, imaging data such as SEM image data of a mask pattern 50 which is drawn in advance on the photomask 40 and evaluated to have a good shape, size, etc. may be used. You may use the mask pattern simulation image data etc. which were obtained by performing drawing simulation by simulation software such as a computer (not shown) based on the data.
The drawing graphic image data DB is image data of a drawing graphic to be evaluated. The drawing graphic image data DB is SEM image data or the like obtained by imaging the mask pattern 50 drawn by the drawing apparatus 10 on the photomask 40 based on the design data or the like.

The evaluation device 30 determines whether or not the reference graphic 1a of the reference graphic image data DA matches the drawing graphic 1b of the drawing graphic image data DB. When the evaluation device 30 determines that the reference graphic 1a of the reference graphic image data DA matches the drawing graphic 1b of the drawing graphic image data DB, the drawing device 10 has drawn a preferred mask pattern 50 on the photomask. To be judged.
Hereinafter, along S10 to S14 shown in FIG. 3, an example of evaluating the drawing figure 1b of FIG. 2B on the basis of the reference figure 1a of FIG. 2A will be described.
First, in S10, the user operates the evaluation device operation unit 31 to start the evaluation program 34a of the evaluation device 30.

(Reference graphic data storage process)
In S11, the evaluation apparatus 30 performs a reference graphic data storage step of performing image processing on the reference graphic image data DA and storing information related to the reference graphic 1a.
FIG. 4 is a flowchart showing a process of storing various information of the reference graphic and the drawing graphic.
In S111, the evaluation device 30 receives the reference graphic image data DA from the evaluation device transmission / reception unit 33 via the communication network.
Then, the image processing unit 36 selects the reference graphic 1a from a predetermined area of the reference graphic image data DA received by the evaluation device transmission / reception unit 33, and performs the following processing on the reference graphic 1a.
First, in S112, the contour line extraction unit 36a extracts the contour line 2a from the reference graphic 1a of the reference graphic image data DA as shown in FIG. The contour line extraction unit 36a extracts, for example, a line that becomes a ridge of the white belt portion of the SEM image of the reference graphic 1a (a line connecting portions with the highest luminance), and extracts this ridge line as the contour line 2a. ing. Note that the present invention is not limited to this example, and boundary lines inside or outside the white belt portion of the image of the reference graphic 1a may be extracted as the outline 2a of the reference graphic 1a.
As such an outline extraction method, for example, a method described in Japanese Patent No. 4417763 or Japanese Patent Application Laid-Open No. 2009-205224 can be appropriately selected and used.

Next, in S113, the area calculation unit 36b calculates the area of the outline 2a of the reference graphic 1a.
Next, in S114, the point sequence calculation unit 36c calculates the point sequence 3a on the xy coordinates constituting the contour 2a from the contour 2a of the reference graphic 1a (see FIG. 2C).
Next, in S115, the principal component analysis unit 36d performs principal component analysis on the point sequence 3a and calculates the first principal component and the second principal component of the point sequence 3a. Specifically, the principal component analysis unit 36d performs principal component analysis on the point sequence 3a, calculates a covariance matrix CA of the point sequence 3a, and obtains a first principal component obtained by eigenvalue decomposition of the covariance matrix CA. And eigenvalues λA1 and λA2 (where λA1 ≧ λA2) of the second principal component are calculated. As shown in FIG. 2C, the directions of the first principal component and the second principal component (the first principal component axis 41a and the second principal component axis 42a) are orthogonal to each other.

Next, in S116, the length-to-short ratio calculating unit 36e is configured such that the length of the first principal component and the length of the second principal component of the point sequence 3a obtained by the principal component analysis of the point sequence 3a by the principal component analysis unit 36d. The reference figure length / shortness ratio RA, which is the ratio of That is, the long / short ratio calculation unit 36e calculates the square root (λA1 / λA2) ^1/2 of the ratio λA1 / λA2 of the two eigenvalues λA1 and λA2 as the reference figure length / shortness ratio RA. This reference figure length-to-short ratio RA indicates the “elongation (flatness)” of the shape of the reference figure 1a. The “elongation” is an extension in a specific direction as a figure. For example, when the reference figure is a circle, the ratio RA = 1.

  In S117, the angle calculation unit 36f calculates the orientation of the first principal component of the point sequence 3a obtained by the principal component analysis of the principal component analysis unit 36d. That is, the angle θA (see FIG. 2C) formed by the eigenvector vA of the first principal component of the point sequence 3a and the x coordinate axis is calculated. This angle θA indicates the “inclination” of the shape of the reference graphic 1a (that is, the above-mentioned “elongation” direction).

  In S118, the information of the reference graphic 1a such as the area of the reference graphic 1a obtained by each processing of the image processing unit 36, the two eigenvalues λA1 and λA2, the reference graphic length / shortness ratio RA, and the angle θA is stored in the evaluation device storage unit 34. Is stored in the reference graphic information storage unit 34b, the reference graphic data storage step is terminated, and the process proceeds to S12.

  In the present embodiment, the evaluation device control unit 35 of the evaluation device 30 calculates the area of the reference graphic 1a, the two eigenvalues λA1, λA2, the reference graphic length / shortness ratio RA, and the like from the reference graphic image data DA. Although the example stored in the information storage unit 34b has been described, the present invention is not limited to this, and the area of the reference graphic 1a, the two eigenvalues λA1, λA2, the reference graphic length / shortness ratio RA, the angle θA, and the like are calculated in advance by another computer or the like. The information may be input from the evaluation device transmission / reception unit 33 and stored in the reference graphic information storage unit 34b. Further, various processes of the image processing unit 36 for the reference graphic 1a and various processes of the image processing unit 36 for the drawing graphic 1b described later may be performed simultaneously.

Next, in S12, the image processing unit 36 acquires SEM image data of the drawing figure transferred from the imaging device 20, detects an area including the drawing figure 1b to be evaluated, and performs various processing steps.
Similar to the above-described reference graphic data storage step, various drawing graphic processing steps will be described with reference to the flowchart shown in FIG.
First, in S <b> 121, the image processing unit 36 acquires the drawing graphic data transferred from the imaging device 20.
(Drawing figure area calculation process)
Next, in S122, the contour line extraction unit 36a detects a region including the drawing figure 1b and extracts the contour line 2b. At this time, the contour line extraction unit 36a, for example, in the same manner as the method for extracting the contour line 2a of the reference graphic 1a described above, is, for example, a broken line on the white belt portion of the image of the drawing graphic 1b (FIG. 2B). Are extracted as the contour line 2b.
Next, in S123, the area calculation unit 36b calculates the area in the outline 2b of the drawing figure 1b extracted by the outline extraction unit 36a. This calculation method is the same as the calculation method of the area of the reference graphic 1a.

(Drawing figure length / short ratio calculation process)
Next, in S124, the point sequence calculation unit 36c calculates the point sequence 3b on the xy coordinates constituting the contour 2b from the contour 2b of the drawing figure 1b (see FIG. 2D).
Next, in S125, the principal component analysis unit 36d performs principal component analysis on the point sequence 3b, and calculates the first principal component and the second principal component of the point sequence 3b.
Next, in S126, the length / shortness ratio calculation unit 36e calculates a drawing figure length / shortness ratio RB that is a ratio of the length of the first principal component and the length of the second principal component of the point sequence 3b. Specifically, eigenvalues λB1 and λB2 (where λB1 ≧ λB2) of the first principal component and the second principal component obtained by eigenvalue decomposition of the covariance matrix CB of the point sequence 3b are calculated, and the eigenvalues are calculated. The square root (λB1 / λB2) ^1/2 of the ratio λB1 / λB2 between λB1 and λB2 is calculated as the drawing figure length / shortness ratio RB. The first principal component axis 41b and the second principal component axis 42b are orthogonal to each other as shown in FIG. The drawing figure length / shortness ratio RB indicates the “elongation (flatness)” of the shape of the drawing figure 1b. This “elongation” is an extension in a specific direction as a figure. For example, when the drawing figure is a circle, the ratio RB = 1.

In S127, the angle calculation unit 36f calculates the direction of the first principal component of the point sequence 3b. That is, the angle θB formed by the eigenvector vB of the first principal component of the point sequence 3b and the x axis is calculated. This angle θB indicates the “tilt” (that is, the direction of “elongation”) of the shape of the drawing figure 1b.
In S128, the drawing figure 1b information such as the area of the drawing figure 1b calculated by the image processing unit 36, the two eigenvalues λB1 and λB2, the drawing figure length / shortness ratio RB, and the angle θB is stored in the drawing figure information storage unit 34c. The stored image processing step relating to the drawing figure 1b is terminated, and the process proceeds to SS13.

S13 is a graphic determination process for determining whether the reference graphic and the drawing graphic match from the area and shape. This graphic determination process includes an area comparison process, a rough similarity determination process, an inclination determination process, and the like.
FIG. 5 is a flowchart of the graphic determination process of the first embodiment.
(Area comparison process)
First, in S131, the area comparison unit 37a calls and compares the area of the reference graphic 1a stored in the reference graphic information storage unit 34b and the area of the drawing graphic 1b stored in the drawing graphic information storage unit 34c. An area comparison step is performed to determine whether or not these are the same (including the case where they are substantially the same).
When the area comparison unit 37a determines that the areas of the reference graphic 1a and the drawing graphic 1b are the same (including cases where they are substantially the same) (S131: YES), this determination result is the drawing graphic information in the evaluation device storage unit 34. The data is stored in the storage unit 34c, and the process proceeds to S132. The case where the area of the reference graphic 1a and the area of the drawing graphic 1b are substantially the same means that the difference between the area of the reference graphic and the area of the drawing graphic is within an allowable range stored in the evaluation table of the evaluation program 34a in advance. This is a case where the difference is small enough to be regarded as the same.
When the area comparison unit 37a determines that the areas of the reference graphic 1a and the drawing graphic 1b are not the same (including cases where they are substantially the same) (S132: NO), the determination result is the drawing graphic information storage unit. 34c, and the process proceeds to S136.

(Roughness similarity determination process)
In S132, the approximate shape determination unit 37b determines whether or not the approximate shapes of the reference graphic 1a and the drawn graphic 1b are similar based on the ratio between the reference graphic length / shortness ratio RA and the drawn graphic length / shortness ratio RB. A shape similarity determination step is performed.
Specifically, the approximate shape determination unit 37b calls the reference figure length / shortness ratio RA stored in the reference figure information storage unit 34b and the drawing figure length / shortness ratio RB stored in the drawing figure information storage unit 34c. These ratios RB / RA are calculated, and this ratio RB / RA is set as a value S _AB (RB / RA = S _AB ).
In the evaluation table of the evaluation program 34a, the outlines of the shapes of the reference graphic 1a and the drawing graphic 1b (the graphic) in the value S _AB (that is, the ratio RB / RA of the reference graphic length / shortness ratio RA and the drawing graphic length / short ratio RB). The allowable value S0 that can be said to be similar is set and stored. This allowable value S0 is a value that satisfies the range of 1 ≦ S0 <2, and the smaller the allowable value S0, the higher the accuracy of determination of the approximate similarity. For example, if S0 = 1.05, it is determined that the approximate shape is similar if the ratio RB / RA (value S _AB ) of the ratio of the reference figure 1a and the drawing figure 1b is within 5%. This allowable value S0 can be appropriately changed by the user by an input from the evaluation apparatus operation unit 31 or the like.

In S132, the approximate similarity determination unit 37b determines that the value S _AB is
1 / S0 ≦ S _AB ≦ S0 (Formula 1)
It is determined whether or not the above is satisfied.
When the value S _AB satisfies this (Formula 1) (S132: YES), the approximate similarity determination unit 37b determines that the reference graphic 1a and the drawing graphic 1b are similar in outline and draws this determination result. The graphic information is stored in the graphic information storage unit 34c, and the process proceeds to S133.
On the other hand, when the value S _AB does not satisfy (Equation 1) (S132: NO), the approximate shape determination unit 37b determines that the reference shape 1a and the drawing shape 1b are not similar in shape, and the determination A result is memorize | stored in the drawing figure information storage part 34c, and it progresses to S136.

(Tilt judgment necessity judgment process)
In S133, the inclination determination necessity determination unit 37c determines whether or not the reference graphic 1a and the drawing graphic 1b are circular (substantially circular with no significant elongation or the like, including shapes that can be regarded as circular). An inclination determination necessity determination process is performed based on whether the long / short ratios RA and RB are larger than an allowable value R0 that can be regarded as a circle or less than an allowable value R0.
This allowable value R0 can be set as appropriate within a range of 1 <R0 ≦ 2, and is stored in advance in the evaluation table of the evaluation program 34a. As the allowable value R0 is set to a value close to 1, both figures having the ratios RA and RB satisfying the allowable value R0 become more circular. When the ratios RA and RB of both figures are equal to or less than the allowable value R0, both figures can be regarded as a circle (including a substantially circle).

In S133, the inclination determination necessity determination unit 37c refers to the reference graphic length / shortness ratio RA stored in the reference graphic information storage unit 34b and the drawing graphic length / shortness ratio RB stored in the drawing graphic information storage unit 34c.
When the reference figure length / shortness ratio RA and the drawing figure length / shortness ratio RB are both greater than the allowable value R0 and RA> R0 and RB> R0 (S133: YES), the inclination determination necessity determination unit 37c It is determined that neither the figure 1a nor the drawing figure 1b is circular (or substantially circular), that is, substantially elliptical or the like, and the process proceeds to S134.
Further, when any one of the reference figure length / shortness ratio RA and the drawing figure length / shortness ratio RB is equal to or less than the allowable value R0 (S133: NO), that is, RA ≦ R0 and RB ≦ R0, RA ≦ R0 and RB> R0, RA In any of the cases of> R0 and RB ≦ R0, the inclination determination necessity determination unit 37c has “elongation” such that at least one of the reference graphic 1a and the drawing graphic 1b needs to determine the inclination. It is determined that it is not a circular shape (including a substantially circular shape).

In the step of performing the inclination determination necessity determination step of S133, it is determined whether or not the value S _AB satisfies (Equation 1) in the preceding approximate similarity determination step of S132, and the reference graphic 1a and the drawing graphic 1b are determined. Are determined to be similar in shape. Also, the values of RA and RB are very close. Therefore, even when RA ≦ R0 and RB> R0, or when RA> R0 and RB ≦ R0, the reference graphic 1a and the drawing graphic 1b can be regarded as a circle (including a substantially circular shape). It can be said that the shapes are similar. Therefore, when the reference graphic 1a and the drawing graphic 1b are circular (including a substantially circular shape) (S133: NO), it can be considered that the inclinations coincide with each other, and the determination of the inclination is unnecessary. Therefore, the inclination determination necessity determination unit 37c stores the determination result in the drawing graphic information storage unit 34c, and proceeds to S135.

(Tilt judgment process)
In S134, the inclination determination unit 37d performs an inclination determination process for comparing the inclinations of the shapes of the reference graphic 1a and the drawing graphic 1b (directions of the first principal components).
Specifically, the inclination determination unit 37d determines that the eigenvector vA of the first principal component of the point sequence 3a of the reference graphic 1a stored in the reference graphic information storage unit 34b is the x θ axis and the drawing graphic information. Reference is made to an angle θB formed by the eigenvector vB of the first principal component of the point sequence 3b of the drawing figure 1b stored in the storage unit 34c and the x axis, and a difference | θA−θB | between the angles θA and θB is calculated. This is the value t _AB (t _AB = | θA−θB |).

Previously, the evaluation table of the evaluation apparatus memory unit 34, the allowable value of the value t _AB t0 (However, t0 ≧ 0 °) is set, it is stored. This allowable value t0 is the maximum value t _AB that can be considered that the inclinations of the reference graphic 1a and the drawing graphic 1b match. Then, the smaller this t0 is, the smaller the difference between the inclinations of both figures is, and it is determined that the inclinations of both figures match. The allowable value t0 can be set as appropriate, such as 10 ° or 30 °, by the user inputting from the evaluation device operation unit 31.
The value t _AB is
0 ° ≦ t _AB <t0 (Formula 2)
In the case of satisfying the above, it can be said that the difference between the inclinations of the reference graphic 1a and the drawing graphic 1b is within the allowable range, and the inclinations of the reference graphic 1a and the drawing graphic 1b are matched (including substantially matching).

In S134, the inclination determination unit 37d determines whether or not the value t _AB satisfies 0 ° ≦ t _AB <t0. When the value t _AB satisfies 0 ° ≦ t _AB <t0 (S134: YES), the inclination determination unit 37d determines that the inclinations of the reference graphic 1a and the drawing graphic 1b match, and the determination result Is stored in the drawing graphic information storage unit 34c, and the process proceeds to S135.
On the other hand, in S134, when the value t _AB does not satisfy 0 ° ≦ t _AB <t0 (t _AB ≧ t0) (S134: NO), the inclination determination unit 37d determines that the reference graphic 1a and the drawing graphic 1b are inclined. Are not matched, the determination result is stored in the drawing graphic information storage unit 34c, and the process proceeds to S136.

Here, the advantage of performing the inclination determination necessity determination step of S133 and the inclination determination step of S134 will be described.
FIG. 6 is a diagram illustrating an example of the reference graphic 1a and the drawing graphic 1b. In FIG. 6, the reference graphic 1a and the drawing graphic 1b are both indicated by point sequences 3a and 3b on the xy coordinates, and the first principal component axes 41a and 41b, the second principal component axes 42a and 42b, and the like are also shown. .
At the stage of performing the inclination determination process of S134, it is determined whether or not the value _SAB satisfies (Equation 1) in the previous outline similarity determination process of S132, and the outlines of the reference figure 1a and the drawing figure 1b are determined. Determined to be similar.

However, as shown in FIG. 6 (a), if the reference graphic 1a and the drawing graphic 1b are both circular or substantially oval shapes that are not substantially circular, the areas of both the figures match and the value S _{Even if AB} satisfies (Equation 1), if the shapes have different inclinations (angles θA, θB), the two figures do not match.
On the other hand, as shown in FIG. 6B, when the reference graphic 1a and the drawing graphic 1b are both circular (including a substantially circular shape), the areas of both the graphics are the same, and the value S _AB is ( If Expression 1) is satisfied, the two figures match even if the orientations of the axes of the first principal component of both figures are different.

  Therefore, it is possible to improve the accuracy of determining whether or not the shapes match by determining whether or not the inclinations match according to the shapes of the reference graphic 1a and the drawing graphic 1b. In the inclination determination necessity determination step, when the inclination determination necessity determination unit 37c determines that both figures are “elongation” within an allowable range and are circular (including substantially circular), The inclination determination process of S134 can be omitted, and the evaluation process can be shortened.

When the above graphic determination process is performed and the process proceeds to S135, in each determination from S131 to S134,
Determination (1) The area comparison unit 37a determines that the area of the reference graphic 1a and the area of the drawing graphic 1b are the same or substantially the same (S131: YES)
Determination (2) The approximate shape similarity determination unit 37b determines that the approximate shapes of the reference graphic 1a and the drawing graphic 1b are similar (S132: YES).
Determination (3) The inclination determination necessity determination unit 37c determines that the area of the reference figure 1a and the drawing figure 1b are circular (including a substantially circular shape) (the inclination determination necessity determination part 37c determines the area of the reference figure 1a and the drawing figure). 1b) (S133: NO), or the inclination determination unit 37d determines that the area of the reference graphic 1a matches the inclination of the drawing graphic 1b (S134: YES).
All of these determinations (1) to (3) are satisfied.
Accordingly, in S135, the graphic determination unit 37 determines that the reference graphic 1a and the drawing graphic 1b match, and stores the determination result in the drawing graphic information storage unit 34c. At this time, the evaluation device control unit 35 displays the determination result on the evaluation device display unit 32. Then, after proceeding to S137 and ending the graphic determination step, the process proceeds to S14 and the image evaluation of a series of drawn graphics is completed.

On the other hand, if any one of the above determinations (1) to (3) is not satisfied in each determination of S131 to S134 in the graphic determination step (that is, S131: NO, S132: NO, S134: NO). ), Go to S136.
In S136, the graphic determination unit 37 determines that the reference graphic 1a and the drawing graphic 1b do not match, and stores the determination result in the drawing graphic information storage unit 34c. At this time, the evaluation device control unit 35 displays the determination result on the evaluation device display unit 32. Then, after proceeding to S137 and ending the graphic determination step, the process proceeds to S14 and the image evaluation of a series of drawn graphics is completed.

When the reference figure 1a and the drawing figure 1b match, the drawing apparatus 10 can evaluate that the drawing figure 1b (mask pattern 50) having a desired shape equal to the reference figure 1a has been drawn on the photomask 40.
When the reference graphic 1 a and the drawing graphic 1 b do not match, the drawing apparatus 10 can evaluate that the drawing graphic 1 b (mask pattern 50) having a desired shape cannot be drawn on the photomask 40.

Here, the reference graphic 1a and the drawing graphic 1b shown in FIG. 2A were evaluated using the above-described image evaluation system. Each limit value, allowable value, and the like are, for example, S0 = 1.05, t0 = 30 °, and R0 = 1.05.
When actually evaluated, it was determined that the reference graphic 1a and the drawing graphic 1b satisfy (Expression 1) and (Expression 2) and match.

Note that the optimum values of these allowable values and limit values S0, R0, and t0 depend on the pattern size, the type of the imaging device 20 (SEM), the magnification of the captured image (SEM image), and the like. Therefore, the above value is an example, and it should be adjusted as appropriate depending on the situation.
For example, the smaller the values are set while satisfying S0> 1, R0> 1, t0> 0 °, the finer detection between both the reference graphic and the drawing graphic becomes possible. However, there is a case where the difference between the shapes of the two figures is caused not by the drawing pattern but by the condition (noise or image distortion) of the imaging device 20. In this case, if the above parameters are set too severely, it is frequently determined that cases that should be determined to be similar are determined not to be similar. This phenomenon is called “pseudo defect”. When such a large number of pseudo defects occur, the value of the parameter should be relaxed.
On the other hand, if the value of the parameter is too large, the criteria for determining the similarity between the two figures will be weakened, and the figure that should be detected as a defect will be overlooked. In such a case, the value of the parameter should be lowered to make the judgment criteria stricter.
Therefore, the determination result may be viewed and fed back as appropriate to adjustment of each allowable value and limit value to improve the determination accuracy.

Another example of evaluating a drawing figure using an image evaluation system provided with the above-described image evaluation method and image evaluation program will be described below. Each allowable value and limit value are S0 = 1.05, t0 = 30 °, and R0 = 1.05.
FIG. 7 is a diagram illustrating an example of the reference graphic 1a and the drawing graphic 1b.
For example, the reference graphic and the drawing graphic shown in FIG. 7A are similar in outline (1 / S0 ≦ S _AB ≦ S0 and 0 ° ≦ t _AB ≦ t0), but have different areas. . Therefore, in this case, in the area evaluation step of S131, the area comparison unit 37a determines that the areas of the reference graphic 1a and the drawing graphic 1b do not match (S131: NO), and the graphic determination unit 37 determines that the reference graphic and the drawing graphic are the same. Judged as inconsistent.

Further, the reference graphic 1a and the drawing graphic 1b shown in FIG. 7B have the same area and the first principal component is close in direction (t _AB ≦ t0), but have different length ratios, and the value S _AB is (Equation 1) is not satisfied (S _AB > S0). Therefore, in the approximate similarity determination step of S132, the approximate similarity determination unit 37b determines that the reference graphic 1a and the drawing graphic 1b are not similar in outline (S132: NO), and the graphic determination unit 37 It is determined that the graphic 1a and the drawing graphic 1b do not match.

Furthermore, although the reference figure 1a and the drawing figure 1b shown in FIG. 7C have the same area and the length ratio satisfies (Equation 1) (1 / S0 ≦ S _AB ≦ S0), the first main The value t _AB which is the direction of the component does not satisfy (Equation 2) (t _AB > t0). Accordingly, in the inclination determination step of S134, the inclination determination unit 37d determines that the inclinations of the reference graphic 1a and the drawing graphic 1b do not match (S134: NO), and the graphic determination unit 37 determines that the reference graphic 1a and the drawing graphic 1b are the same. It is determined that they do not match.

  As described above, by using the evaluation method and the evaluation program of the present embodiment, it is possible to accurately and easily determine whether or not the reference graphic 1a and the drawing graphic 1b having various shapes match. . For example, as in the case where the drawing figure 1b is circular, the figure itself changes greatly only by slightly moving the cross-sectional line to be measured in the conventional general dimension measurement in the vertical direction. In this case, the evaluation process can be simplified, and the efficiency such as evaluation time can be improved. Further, when only the area is used as a criterion for image evaluation, even if the shape of the reference graphic 1a and the shape of the drawing graphic 1b are largely different, if the areas match, the reference graphic 1a and the drawing graphic 1b are Although it may be determined that they match, according to the present embodiment, in addition to the area of the drawing figure 1b, the length ratio of the drawing figure 1b is taken into the determination criterion. The determination accuracy can be improved as compared with the case where the determination is made only by the area.

In addition, according to the present embodiment, whether or not the reference graphic 1a and the drawing graphic 1b are coincident with each other is determined by using the values S _AB and t _AB representing the elongation and inclination of the two graphics in addition to the areas of the two graphics. Since it is determined, it can be determined uniformly by a mathematical method and the accuracy of evaluation can be improved.
Furthermore, according to the present embodiment, since the inclination determination necessity determination step is provided, whether or not the inclination of the drawing figure 1b and the inclination of the reference figure 1a match according to the shapes of the reference figure 1a and the drawing figure 1b. Therefore, the evaluation process can be simplified.
Furthermore, according to the present embodiment, the reference figure 1a can use a figure on imaging data obtained by imaging a drawing figure previously drawn on a photomask as a comparison reference. Then, a drawing figure whose shape becomes a desired shape can be used as the reference figure 1a. Moreover, since the reference figure 1a can use the figure obtained by the simulation which draws on a photomask using design data as a comparison reference, let the desired shape obtained by simulation be the reference figure 1a. Can do.

(Second Embodiment)
FIG. 8 is a flowchart of the graphic determination process of the second embodiment.
In the first embodiment described above, the inclination determination unit 37d uses the value t _AB = | θA−θB | indicating the inclination of the reference figure and the drawing figure in the inclination determination step, and the inclination of the reference figure 1a and the drawing figure 1b. An example of determining whether or not matches is shown. In the second embodiment, this value t _AB is not used, and the inclination determination unit 37d determines the inclination of the reference graphic 1a and the drawing graphic 1b using the value U _{AB represented} by the following equation 2 using a matrix norm. Is different.
Therefore, in the second embodiment, parts that perform the same functions as those in the first embodiment described above are denoted by the same reference numerals or the same reference numerals at the end, and repeated descriptions are omitted as appropriate.

（式３）において、右辺の分子は、２×２正方行列同士の通常の積を表し、得られる値も、２×２行列となる。右辺の分母は、正の実数同士の通常の積を表す。
値Ｕ_ＡＢは、その行列ノルムが、一例として、上記（式３）に示すようなベクトルのユークリッドノルムからの誘導ノルムである例を挙げて説明する。なお、本実施形態では、誘導ノルムを用いる例を挙げて説明するが、これに限らず、他のノルムを用いてもよい。
この誘導ノルムは、作用素ノルムとも呼ばれ、任意の行列Ｍに対して、

In (Expression 3), the numerator on the right side represents a normal product of 2 × 2 square matrices, and the obtained value is also a 2 × 2 matrix. The denominator on the right side represents the normal product of positive real numbers.
The value U _AB is the matrix norm, as an example, be described by way of example is a derived norm from the Euclidean norm of a vector such as shown in (Equation 3). In the present embodiment, an example using the induction norm will be described. However, the present invention is not limited to this, and other norms may be used.
This induction norm is also called an operator norm, and for an arbitrary matrix M,

という関係を満たす。このとき、上記の式の右辺の分子及び分母は、ベクトルのノルムであり、ユークリッドノルムとする。

Satisfy the relationship. At this time, the numerator and denominator on the right side of the above expression are the norm of the vector, and the Euclidean norm.

  When the matrix norm described above is selected, the norm value of an arbitrary matrix M can be obtained as the maximum singular value. That is,

という式で得られる。ただし、Ｍ^＊は、行列Ｍの随伴行列（共役転置行列）を表し、λは固有値を示し、λ_ｍａｘは、その中で最大のものを示す。

It is obtained by the formula. Here, M ^* represents an adjoint matrix (conjugate transpose matrix) of the matrix M, λ indicates an eigenvalue, and λ _max indicates the maximum value among them.

  The submultiplicity property holds for the matrix norm selected as described above. That is, for any matrix,

という関係が成り立つ。
従って、上述の値ｕ_ＡＢは、（式３）で表されるので、
０≦Ｕ_ＡＢ≦１ ・・・（式７）
となる。この値Ｕ_ＡＢは、両図形が楕円形状等のように伸びを有している場合には、その値が１に近いほど、より傾きが一致している度合いが高いということを示し、かつ、両図形が円形（略円形である場合を含む）である場合には、その角度θＡ及び角度θＢに関わらず、１に近い値を示す。

This relationship holds.
Therefore, the above-mentioned value u _AB is expressed by (Equation 3).
0 ≦ U _AB ≦ 1 (Expression 7)
It becomes. This value U _AB indicates that, when both figures have an extension such as an elliptical shape, the closer the value is to 1, the higher the degree of inclination coincides, and When both figures are circular (including the case of a substantially circular shape), a value close to 1 is shown regardless of the angle θA and the angle θB.

As shown in FIG. 8, in the graphic determination process of the second embodiment, an inclination determination process of S333 is performed instead of the inclination determination necessity determination process of S133 and the inclination determination process of S134 shown in the first embodiment. The graphic determination unit 37 of the second embodiment does not include an inclination determination necessity determination unit, and the inclination determination process in S333 is performed by using the value U _AB as described later. Determine whether you are doing it.
In this embodiment, the limit value U0 of this value U _AB is set in advance and stored in the evaluation table of the evaluation program 34a. This limit value U0 is preferably set within a range of 0.6 ≦ U0 ≦ 1, and can be set as appropriate by the user through the evaluation apparatus operation unit 31.

In the graphic determination process of this embodiment, when it is determined in the approximate similarity determination process in S132 that the approximate shapes of the reference graphic 1a and the drawing graphic 1b are similar (S132: YES), the process proceeds to S333. Then, the inclination judgment step of S333, the tilt determining unit 37d calculates the value _{U AB,} the value _{U AB} is,
U0 ≦ U _AB ≦ 1 (Expression 7)
It is determined whether or not the above is satisfied.
When the value U _AB satisfies (Expression 7), the inclination determination unit 37d determines that the inclinations of the reference graphic 1a and the drawing graphic 1b match (including substantially matching), and the determination result is used as the drawing graphic information storage unit 34c. And proceed to S135. When the value U _AB = 1, since both figures are circular, the slopes can be regarded as matching.
When the value U _AB does not satisfy (Equation 8), the inclination determination unit 37d determines that the inclinations of the reference graphic 1a and the drawing graphic 1b do not match, and the process proceeds to S136.

By using the above-described value U _AB , the inclination can be determined in the same process without exception when both the reference graphic 1a and the drawing graphic 1b are circular. Therefore, the inclination determination necessity determination step of S133 and the circular determination step of S238 as shown in the first embodiment and the second embodiment are not required. In addition, there is an advantage that the accuracy of evaluation is not lowered, the graphic determination process is facilitated, and the process is shortened.
Therefore, according to this embodiment, it is possible to simplify the evaluation process of the drawing figure 1b while maintaining high determination accuracy, and to perform determination processing efficiently.

(Third embodiment)
In the third embodiment, a drawing condition selection method using the above-described image evaluation method will be described.
The drawing condition selection method of the present embodiment is a method for calculating preferable drawing conditions (conditions relating to drawing) for the drawing apparatus 10 to draw a drawing figure 1b having the same shape as the reference figure 1a. It is assumed that drawing is performed based on the following staged data 200 calculated from the data 100.
FIG. 9 is a diagram for explaining the setting data 200.
In general, a designer first creates design data 100 as shown in FIG. The design data 100 is created from the shape of a desired wiring pattern that is actually formed on a semiconductor wafer. The design data 100 is created using a design apparatus (not shown) such as CAD.
Next, as shown in FIG. 9B, the designer creates mask data 100 </ b> A (drawing planned pattern) based on the design data 100. The mask data 100A is polygonal data created using a technique such as OPC (Optical Proximity Effect Correction). The mask data 100A may be created using a design device (not shown) such as CAD, or may be created using a dedicated design device.

Then, as shown in FIG. 9 (c-1), stepped data 200 (corresponding to shot shape array drawing data) is created from the mask data 100A. Note that FIG. 9C-1 shows the stepped data 200 corresponding to the shape within the broken line of the mask data 100A of FIG.
The stepped data 200 is obtained by arranging a plurality of rectangles 300 based on the mask data 100A. Each rectangle 300 corresponds to a shot shape when drawing an electron beam. The stepped data 200 is arranged so that a plurality of rectangles 300 overlap.
The stepped data 200 may be created using a design device such as CAD, or may be created using a dedicated design device.

Next, as shown in FIG. 9D, the mask pattern 50 is drawn on the photomask 40 by using the stepped data 200 by the drawing apparatus 10. The drawing apparatus 10 draws by irradiating a predetermined amount of an electron beam for each rectangle 300 using an aperture having a shape corresponding to each rectangle 300.
The photomask 40 can be used to transfer onto a semiconductor wafer (not shown) with an exposure apparatus such as a stepper, thereby forming a wiring pattern on the semiconductor wafer.

The shape of the mask pattern 50 formed by using the stepped data 200 in the above process is created as a drawing data 102 combining rectangles of different shapes based on the design data 100 as has been conventionally done. (See FIG. 9C-2), the same pattern as the mask pattern drawn on the photomask based on the drawing data 102 can be obtained. The reason for this is as follows.
In the case where the stepped data 200 is used, the outer corner 300a of the rectangle 300 becomes smaller as the amount of the electron beam irradiated becomes smaller at the tip, so that the contour of the mask pattern 50 becomes narrower on the inner side. Becomes a curve. In addition, since the rectangle 300 overlaps the inner corner portion 300b, the electron beam is irradiated for each shot, the dose increases, the contour of the mask pattern 50 bulges outward, and the contour becomes a curve. For this reason, as shown in FIG. 9D, a mask pattern 50 having a shape in which corner portions are smoothly connected with a curve is drawn on the photomask 40.

  Since the stepped data 200 has a smaller number of rectangles 300 than the conventional drawing data 102, the creation of data is easy. Further, when the mask pattern 50 is drawn on the photomask 40, the number of shots can be remarkably reduced as compared with the prior art. For this reason, the production time of the photomask 40 can be significantly reduced, and the operation time of the expensive drawing apparatus 10 can be reduced, so that the cost of the photomask 40 can be reduced.

Since the drawing apparatus 10 of the present embodiment draws the mask pattern 50 on the photomask 40 using the above-described stepping data 200, the drawing apparatus 10 has several conditions (drawing conditions) relating to drawing that can be set by the user. Examples of the drawing conditions include a dose amount and a backscatter parameter amount. By setting these appropriately, a desired mask pattern 50 can be drawn on the photomask 40.
In the case of the general fracture drawing data 102 (see FIG. 9C-2), the figure of the mask data 100A is broken down into finer rectangular figures, and drawing is performed for each rectangular figure. . Therefore, only the exposure amount is necessary for drawing, and there is one drawing condition that needs to be set. However, when drawing is performed using the above-described staged data 200 (see FIG. 9C-1), there are a plurality of drawing conditions that need to be set as described above. Therefore, when drawing using the stepped data 200, it is not possible to obtain a preferable drawing figure only by setting one drawing condition. In addition, unless the optimum drawing conditions are set, the shape and area shift between the drawing figure and the reference figure increases, and the reference figure and the drawing figure do not match.

  Further, the drawing conditions need to be appropriately changed depending on the characteristics of the resist of the photomask, the characteristics of the drawing apparatus, and the like. For example, even if a drawing apparatus conforms to the same standard, a preferred drawing condition may be different when the drawing apparatus is changed to another drawing apparatus. At this time, when there are a plurality of drawing conditions as described above, various combinations are generated, and it is difficult to set the drawing conditions. In addition, when drawing the same mask pattern as the mask pattern drawn using the conventional fracture-type drawing data 102 using the stepped data 200 as described above, the user sets values for preferable drawing conditions. Is difficult to set.

In this embodiment, a method for selecting an optimum drawing condition will be described.
In the following description, among the drawing conditions that allow the drawing figure 1b equal to the reference figure 1a to be drawn on the photomask 40, the shape (elongation, inclination) of the drawing figure 1b is similar to the shape of the reference figure 1a. The drawing condition that affects whether or not it is called a rough shape similarity condition, and the drawing condition that affects the area (size) of the drawing figure 1b is defined as the area condition. In the present embodiment, an example will be described in which an optimum value of the backscattering parameter amount is determined as the approximate shape condition, and an optimal value of the dose (DOSE) amount is determined as the area condition. However, various parameters affecting the similarity of the shape (rough shape) and the area may be appropriately selected as the rough shape similarity condition and the area condition.

FIG. 10 is a diagram illustrating the image evaluation system 3 according to the third embodiment.
FIG. 11 is a flowchart illustrating a drawing condition selection method according to the third embodiment.
In the image evaluation system 3 of the present embodiment, the optimum condition selection program 34d is stored in the evaluation device storage unit 34 of the evaluation device 30, and the graphic determination unit 37 of the evaluation device control unit 35 includes a drawing condition selection unit 37e. Except for the differences, the configuration is substantially the same as the evaluation system of the first embodiment described above. Accordingly, the same reference numerals are given to portions that perform the same functions as those in the first embodiment described above, and redundant description will be omitted as appropriate.
First, in S40, the user operates the evaluation apparatus operation unit 31 to activate the optimum condition selection program 34d, and proceeds to the reference graphic data storage step in S41.

(Reference graphic data storage process)
In S41, the image processing unit 36 performs image processing on the reference graphic image data DA acquired from the evaluation device transmission / reception unit 33, and performs various types of information on the reference graphic 1a (that is, the area of the reference graphic 1a, the reference graphic length / shortness ratio RA, the angle). A reference graphic data storing step for calculating and storing θA and the like is performed.
First, the contour extraction unit 36a selects the reference graphic 1a of the reference graphic image data DA and extracts the contour 2a. Then, the area calculation unit 36b calculates the area in the outline 2a, and the point sequence calculation unit 36c calculates the point sequence 3a constituting the contour 2a on the xy coordinates. In the present embodiment, one or a plurality of circular mask patterns are selected from the reference graphic image data DA and set as the reference graphic 1a. It is assumed that the reference graphic 1a is drawn according to the drawing condition A.

Next, the principal component analysis unit 36d performs principal component analysis on the covariance matrix CA of each point sequence 3a. Then, the length-to-short ratio calculating unit 36e calculates the reference graphic length-to-short ratio RA of the reference graphic 1a, and the angle calculating unit 36f calculates the angle θA formed by the eigenvector vA of the first principal component of each reference graphic 1a and the x-axis. To do. Information regarding the reference graphic 1a obtained by the image processing unit 36 is stored in the reference graphic information storage unit 34b.
Then, after performing the above-described reference graphic data storing step, the process proceeds to S42.

(Rough shape similar condition selection process)
Next, in S42 to S44, a rough similar condition selection step is performed.
This outline similarity condition selection step is a process of selecting a drawing condition having an outline similarity condition capable of drawing a drawing figure having high outline similarity to the reference figure from a plurality of outline similarity conditions. In the rough similarity condition selection step of the present embodiment, all other conditions among the drawing conditions are the same, but only the rough similarity condition (backscatter parameter amount) is set to a different value, and the drawing apparatus 10 uses the photomask. An example will be described in which a drawing figure 1b having the highest degree of similarity to the reference figure 1a is determined from the drawing figures 1b (mask pattern 50) drawn on 40. In this step, the difference in area between the reference graphic 1a and the drawing graphic 1b is not considered. The outline similarity condition can be set as appropriate by the user.
The reason why the backscattering parameter amount is selected as the approximate shape similarity is that the backscattering parameter amount is the shape of the drawn figure in the case of drawing using the stepped data 200 having overlap as in the drawing device 10 of the present embodiment. This is because it greatly affects

First, in S42, the imaging device 20 images the drawing figure 1b drawn by the drawing apparatus 10 on the photomask under the drawing conditions that differ only in the approximate shape similarity condition, and the image data (drawing figure data) is transmitted and received by the evaluation apparatus. The data is transferred to the evaluation device 30 via the unit 33.
Next, the image processing unit 36 selects each drawing figure 1b on which a pattern corresponding to the above-described reference figure 1a is drawn from a predetermined area of the drawing figure image data DB received from the evaluation device transmission / reception unit 33, and displays various images. Process.
The contour line extraction unit 36a performs image processing on each drawing graphic image data DB and extracts the contour line 2b of each drawing graphic 1b.
The point sequence calculation unit 36c calculates the point sequence 3b constituting the outline 2b of each drawing figure 1b on the xy coordinates.

Next, the principal component analysis unit 36d calculates the covariance matrix CB by performing principal component analysis on the point sequence 3b of each drawing graphic 1b, and calculates the first principal component and the second principal component of each drawing graphic 1b.
Next, the long / short ratio calculation unit 36e calculates the eigenvalues of the first principal component and the second principal component of each drawing figure 1b, and calculates the drawing figure length / shortness ratio RB of each drawing figure 1b.
Further, the angle calculation unit 36f calculates an angle θB that the eigenvector vB of the first principal component of each drawing figure 1b makes with the x axis.
Information such as the length ratio RB and the angle θB of the drawing figure 1b calculated by the image processing unit 35a is stored in the drawing figure information storage unit 34c.

In S43, the graphic determination unit 37 determines whether or not the rough shapes of the reference graphic 1a and the drawing graphic 1b are similar.
Specifically, the approximate similarity determination unit 37b of the graphic determination unit 37 is different from each reference graphic length-to-short ratio RA in each drawing condition (for example, the drawing conditions B1-1 and B2 shown in FIG. 12). -1 and B3-1), it is determined whether or not the rough shape of the reference graphic 1a and each drawing graphic 1b is similar based on the difference in size between the drawing graphic length / shortness ratio RB of each drawing graphic drawn The approximate similarity determination step is performed.
In S43, the approximate shape determination unit 37b calculates a value S _AB from the reference figure length / shortness ratio RA and the drawing figure length / shortness ratio RB, and this value S _AB is (Equation 1) 1 / S0 ≦ S _AB ≦ S0. It is determined whether or not the above is satisfied. The determination result is stored in the drawing graphic information storage unit 34c.

  In the present embodiment, since the reference graphic 1a is both circular, an inclination determination step for determining whether or not the inclinations of the reference graphic 1a and the drawing graphic 1b match each other, and an inclination for determining whether or not the inclination determination step is necessary. The determination necessity determination process, the circular determination process, and the like are not performed. However, the present invention is not limited to this, and when the reference graphic 1a is other than a circle (including a substantially circular shape), an inclination determination necessity determination step, a circle determination step, and an inclination determination step are performed after the above-described approximate similarity determination step. It is possible to select a drawing condition in which the shape matches with higher accuracy by determining whether or not the inclinations of the reference graphic 1a and the drawn graphic 1b are similar to each other in addition to the similarity between the reference graphic 1a and the drawn graphic 1b.

Next, in S44, the drawing condition selection unit 37e calls the result of the approximate similarity determination process in S43 from the drawing figure information storage unit 34c, and among the drawing figures drawn under each drawing condition, the drawing condition selection unit 37e is the most approximate to the reference figure 1a. The one having a high similarity in shape is selected, and the approximate similarity condition of the drawing condition for drawing the drawing figure 1b is the optimum outline similarity condition that can draw the drawing figure that is most similar to the reference figure 1a. Select as being.
Here, the drawing condition selection unit 37e calculates, for each drawing condition, an average value of the absolute values of log (S _AB ) over all the drawing figures to be evaluated from the value S _AB obtained from the drawing figure and the reference figure. Then, the drawing condition that minimizes the average absolute value of log (S _AB ) is selected as the optimum outline similarity condition that can draw the drawing figure that is most similar to the reference figure 1a.

As another method, for example, when there are a plurality of drawing figures 1b drawn under each drawing condition (for example, ten pieces for one drawing condition), the drawing condition selection unit 37e is roughly combined with the reference figure 1a. Select the one with the largest number of similar shapes, and draw the rough outline of drawing conditions for drawing the drawing figure 1b, and the optimum outline that can draw the drawing figure whose outline is most similar to the reference figure 1a You may select as being similar conditions. If there is one drawing figure drawn under each drawing condition, the drawing figure having the value _SAB closest to 1 is selected as the drawing figure having the highest approximate shape similarity. The approximate similarity condition may be selected as the optimum approximate similarity condition.
As a result, a condition in which the outline of the drawing figure is most similar to the outline of the reference figure is selected from a plurality of outline similarity conditions. The selected approximate shape similarity condition is stored in the drawing graphic information storage unit 34c, and the process proceeds to the next S45.

(Area condition selection process)
Next, an area condition selection process is performed in S45 to 47. This area condition selecting step is a step of selecting a condition in which the area of the drawing figure 1b is the same as (or substantially the same as) the area of the reference figure 1a from among a plurality of area conditions.
First, in S45, the approximate similarity condition selected in the approximate similarity condition selection step (in this embodiment, the amount of backscattering parameters) is transferred to the drawing apparatus 10 via the evaluation apparatus transmission / reception unit 33. The user has a plurality of drawing conditions (for example, drawing conditions B1-1 and B1 shown in FIG. 13) that are different in only the area condition (in this embodiment, the dose amount), although the approximate similarity condition and other drawing conditions are constant. -2, B1-3), the drawing apparatus 10 draws a drawing figure (mask pattern 50) on the photomask 40, and the drawing apparatus 1 images the drawing figure 1b.
The dose amount as the area condition greatly affects the area (size) of the drawing figure 1b in the case of drawing the mask pattern 50 using the stepped data 200 including the overlap as in the present embodiment. Therefore, in this embodiment, the dose amount is set as the area condition.

Next, the image processing unit 36 selects a drawing figure 1b from a predetermined area of the drawing figure image data DB under each drawing condition, and performs various image processing on each drawing figure 1b.
First, the contour line extraction unit 36a detects a region including each drawing graphic 1b, performs image processing on the imaging data (drawing graphic data), and extracts the contour line 2b of the drawing graphic 1b. The area calculation unit 36b calculates the area within the outline 2b of each drawing figure 1b. The obtained area of each drawing figure 1b is stored in the drawing figure information storage unit 34c.

  Next, in S46, the area comparison unit 37a determines the area of each reference graphic 1a stored in the reference graphic information storage unit 34b and the area of the drawing graphic 1b of each drawing condition stored in the drawing graphic information storage unit 34c. Are compared to determine whether or not they are the same (including substantially the same). The determination result is stored in the drawing graphic information storage unit 34c.

Next, in S47, the drawing condition selection unit 37e calls the result of the area comparison process in S46 from the drawing figure information storage unit 34c, and among the drawing figures 1b drawn under each drawing condition, the area of the reference figure 1a and the area is the most. The matching one is selected, and the area condition of the drawing condition for drawing the drawing figure 1b is selected as the optimum area condition that can draw the drawing figure that has the area most similar to the reference figure 1a.
The drawing condition selection unit 37e calculates, for all drawing figures to be evaluated, the differences of the three determination items of the area, length ratio (elongation), and inclination of the drawing figure for each drawing condition with respect to the reference figure. As a result, three values indicating the deviation between the drawing figure drawn under each drawing condition and the reference figure are obtained for each drawing condition. Here, the “difference” refers to, for example, the difference between the areas, the length S / R ratio, for example, the value S _AB , and the angle, for example, the difference between the angles (however, 0 ° or more) The side that is less than 180 ° can be used as an index, but is not limited thereto.
The drawing condition selection unit 37e minimizes the difference in area among the drawing conditions in which the difference between the length ratio (elongation) and the inclination are both within a predetermined constant value in the difference among the three items. Is selected as a drawing figure whose area is the same as that of the reference figure 1a, and the area condition is selected as the optimum area condition.
It should be noted that the user can appropriately set which of these three items is to be preferentially considered, and can also be used in the above-described approximate similarity condition selection step.

  Further, for example, as another method, the drawing condition selection unit 37e determines that when there are a plurality of drawing figures 1b drawn under each drawing condition (for example, 10 pieces per drawing condition), the reference figure 1a and the area The drawing condition with the largest number of drawing figures 1b determined to be the same is selected, and the area condition of the drawing condition is selected as the optimum area condition for drawing the drawing figure 1b having the same area as the reference figure 1a. Also good. Further, when there is one drawing figure 1b drawn under each drawing condition, the drawing figure having the smallest area difference from the reference figure 1a among the drawing figures 1b is drawn with the area that is the same as that of the reference figure 1a. It may be selected as a figure, and the area condition may be selected as the optimum area condition.

  In addition, when there are a plurality of drawing figures for each drawing condition, it is not determined whether the individual figure is similar to the reference figure or the area is matched. Evaluate overall growth similarity, overall slope similarity, and area similarity in a group, treat the group as a single figure, determine similarity to a reference figure, and approximate similarity It is good also as a form which selects conditions and area conditions.

  Thereby, an area condition in which the area of the drawing figure 1b and the area of the reference figure 1a are the same or substantially the same is selected from the plurality of area conditions. The area condition is stored in the drawing graphic information storage unit 34c, and the process proceeds to S48.

(Drawing condition selection process)
In S <b> 48, the drawing condition selection unit 37 e selects the approximate similarity condition (backscatter parameter amount) selected in the approximate similarity condition setting step in S <b> 42 to S <b> 44 described above and the area condition selected in the area condition setting step in S <b> 45 to 47. (Dose amount) is called from the drawing figure information storage unit 34c, and the combination of the rough shape similarity condition and the area condition is selected as the optimum drawing condition for drawing the drawing figure 1b that matches the reference figure 1a. Further, the evaluation device control unit 35 displays each selected condition on the evaluation device display unit 32, proceeds to S49, and ends the drawing condition selection program.
By performing the above steps, it is possible to easily select the drawing conditions having the optimum outline similarity condition and the area condition that can draw the drawing figure 1b that matches the reference figure 1a.

FIG. 12 shows a drawing figure (B1-1, B2-1, B3-1) drawn under different drawing conditions (B1-1, B2-1, B3-1) from the reference figure (20 pieces) drawn under the drawing conditions (condition A). It is a figure which compares 20) for each drawing condition.
Here, the drawing conditions having different outline similar conditions are three drawing conditions B1-1, B2-1, and B3-1. However, the number of drawing conditions having different outline similar conditions is not limited. You may select suitably. Further, the number of reference figures is 20, and the number of drawing figures is 20 as the number of reference figures for each drawing condition. Each drawing figure corresponds to each reference figure.

FIG. 12A shows the area of each drawing figure drawn under each reference figure and each drawing condition. FIG. 12B shows the ratios RA and RB of each drawing figure drawn with each reference figure and each drawing condition, and FIG. 12C shows each drawing drawn with each reference figure and each drawing condition. The angles θA and θB of the figure are shown. The reference figures 1a are all circular.
In FIG. 12A, as a parameter for comparing the areas of the reference graphic 1a and the drawing graphic 1b, the diameter (area diameter converted value) calculated from the areas in the contour lines 2a and 2b of the reference graphic 1a and the drawing graphic 1b is used. Used. As shown in FIG. 12 (a), when the drawing figure drawn under each drawing condition having a different rough shape similarity condition from the reference figure only by area (area diameter converted value) is evaluated, the drawing condition B2-1 It can be determined that the drawing figure 1b drawn in step 1 is closest to the reference figure 1a (condition A).

However, as shown in FIG. 12B, when comparing the length ratio of the reference graphic 1a and each drawing graphic 1b, the drawing graphic drawn under the condition B1-1 among the drawing conditions having different approximate shape similar conditions is as follows. The drawing figure drawn under the conditions B2-1 and B3-1 is shorter than the drawing figure drawn under the condition B1-1. The difference from the ratio is large, and the shape extends in a predetermined direction.
Also, regarding the angle θB, as shown in FIG. 12C, the drawing figure drawn under the condition B1-1 is the closest to the reference figure (condition A) among the drawing conditions having different approximate shape similar conditions. On the other hand, the drawing figure drawn under the conditions B2-1 and B3-1 has a larger difference from the angle θA of the reference figure than the drawing figure drawn under the condition B1-1.
Therefore, the condition B1-1 is selected as the most suitable approximate shape similarity condition.

That is, when trying to select the condition closest to the condition A from among the three conditions B1-1, B2-1, and B3-1, the comparison is performed using only the figure area as shown in FIG. Then, it is determined that the condition B2-1 is optimal. However, as shown in FIGS. 12B and 12C, if the “elongation” and “slope” of the figure (that is, the similarity of the outline) is also taken into consideration as a criterion, the condition B2-1 is “ It can be seen that the “elongation” tends to be inferior to the condition B1-1 and the “tilt” tends to be in a direction close to −90 °.
Therefore, Condition B2-1 is inappropriate for adopting the drawing condition close to the drawing condition A because the area of the drawn figure is close to the condition A but the figure tends to extend in the longitudinal direction. I understand. This is one of the effects obtained by obtaining not only “area” but also “elongation” and “inclination” (similarity of outlines) as determination criteria and obtaining optimum conditions.

  As shown in FIGS. 12A to 12C, among the above three conditions (conditions B1-1, B2-1, and B3-1), an “area” standard, “elongation”, and “inclination” are included. There is no optimal condition that satisfies both standards. Therefore, in order to find such an optimum drawing condition, it is necessary to change the drawing condition to another dimension (second drawing parameter that can be changed independently of the first drawing parameter).

FIG. 13 shows drawing figures (each drawing condition) drawn under drawing conditions (B1-1, B1-2, B1-3) that are different from the reference figure (20 pieces) drawn under the drawing conditions (condition A). It is a figure which compares (20 pieces per).
Here, the general shape similarity conditions are common and the optimal one is selected, but an example in which the optimal area condition is selected from three drawing conditions with different area conditions has been described. The number of area conditions may be selected as appropriate. In addition, for each drawing condition (drawing conditions B1-1, B1-2, and B1-3 that differ only in the area condition), 20 drawing figures are selected, and these are compared with the reference figure.

FIG. 13A shows the area of the reference graphic and the drawing graphic drawn under each drawing condition. FIG. 13B shows the length ratio of the reference graphic and the drawing graphic drawn under each drawing condition, and FIG. 13C shows the angle between the reference graphic and the drawing graphic drawn under each drawing condition. . In FIG. 13A, as in FIG. 12A, a diameter (area diameter converted value) calculated from the area is used as an index indicating the area.
As shown in FIG. 13A, the vertical movement tendency of the area shows any drawing figure drawn under the drawing conditions B1-1 to B1-3 having different area conditions and is close to the reference figure. Yes.
The drawing figure drawn under the condition B1-1 tends to have a larger area than the reference figure. On the other hand, many of the drawn figures drawn under the conditions B1-2 and B1-3 have an area close to the area of the reference figure. In particular, what is drawn under the condition B1-3 is close to the reference figure. Most often.

At this time, as shown in FIGS. 13B and 13C, the drawing figures drawn under the conditions B1-1 to B1-3 are similar in outline shape that can draw drawing figures having high outline similarity. Since the conditions are selected, the elongation and inclination (long / short ratio and angle) are both close to the reference figure.
Accordingly, comprehensively determined, the drawing figure drawn under the drawing condition B1-3 has the highest degree of coincidence with the reference figure, and the drawing condition B1-3 is similar in shape to the reference figure. The degree of coincidence of the characteristics and the area is the highest, and it can be said that the drawing conditions are optimum.

  Therefore, according to the present embodiment, a preferable drawing condition can be selected easily and with high accuracy in consideration of not only the criterion of closeness of the area but also the criterion of expansion and inclination of the outline. it can.

(Deformation)
Without being limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In the first embodiment, an example in which the inclination determination necessity determination unit and the inclination determination necessity determination step are provided has been described. However, in the inclination determination necessity determination unit and the inclination determination necessity determination step, the reference graphic is circular ( If it is not (including a substantially circular shape), it may be omitted.

(2) In the first embodiment and the second embodiment, the example in which the area comparison process is performed first and then the approximate similarity determination process, the inclination determination process, and the like is shown. You may perform a process, an inclination determination process, etc. previously, and may perform an area comparison process after that.

(3) In the third embodiment, an example is shown in which the backscattering parameter amount is set as the rough shape similarity condition and the dose amount is set as the area condition. However, the present invention is not limited to this, and other parameter conditions may be used.

(4) In each embodiment, although the evaluation apparatus 30 is a separate body from the drawing apparatus 10 and the imaging apparatus 20 and has shown an example in which various types of information can be communicated, the present invention is not limited thereto. Or it is good also as a form incorporated in the imaging device 20. FIG.

(5) In the third embodiment, the example in which the approximate similarity condition is first selected and then the area condition is selected has been described. However, the present invention is not limited to this. It is good also as a form which selects shape similarity conditions.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the embodiments described above.

DESCRIPTION OF SYMBOLS 1 Image evaluation system 10 Drawing apparatus 20 Imaging apparatus 30 Evaluation apparatus 35 Evaluation apparatus control part 36 Image processing part 37 Graphic determination part 40 Photomask 50 Mask pattern

Claims (15)

An image evaluation method for comparing a drawing figure drawn on a photomask with a reference figure that is a comparison reference of the drawing figure,
The first principal component and the second principal component obtained by principal component analysis of the area of the reference graphic, the outline of the reference graphic, the length of the first principal component and the second main component of the outline of the reference graphic A reference graphic data storage step for storing data relating to a reference graphic length / short ratio which is a ratio of component lengths;
A drawing figure area calculating step of performing image processing on imaging data of the drawing figure and calculating an area of the drawing figure;
The imaging data of the drawing figure is subjected to image processing, the outline of the drawing figure is subjected to principal component analysis to calculate the first principal component and the second principal component, and the length of the first principal component of the outline of the drawing figure is calculated. A drawing figure length / shortness ratio calculating step for calculating a drawing figure length / shortness ratio, which is a ratio between the length and the length of the second main component;
An area comparison step of comparing the area of the reference graphic stored in the reference graphic data storage step with the area of the drawing graphic calculated in the drawing graphic area calculation step to determine whether or not they are the same or substantially the same When,
Based on the ratio between the reference figure length / shortness ratio stored in the reference figure data storage step and the drawing figure length / shortness ratio calculated in the drawing figure length / shortness ratio calculation step, the rough shape of the reference figure and the drawing figure is similar. An approximate similarity determination step for determining whether or not
A graphic determination step for determining whether or not the reference graphic and the drawing graphic match based on the results of the area comparison step and the approximate shape determination step;
The graphic determination step includes
When it is determined in the approximate similarity determination step that the reference graphic and the rough shape of the drawing graphic are similar, and in the area comparison step, the area of the reference graphic and the area of the drawing graphic are the same or substantially the same. When it is determined that there is, it is determined that the reference graphic matches the drawing graphic,
When it is determined in the approximate similarity determination step that the reference graphic and the drawing graphic are not similar to each other, and in the area comparison step, the area of the reference graphic and the area of the drawing graphic are not the same or substantially the same. In at least one case of determining that the reference graphic and the drawing graphic do not match,
An image evaluation method characterized by the above. The image evaluation method according to claim 1,
The direction of the axis of the first principal component of the reference figure stored in the reference figure data storage step is compared with the direction of the axis of the first principal component of the drawing figure calculated in the drawing figure length / shortness ratio calculating step. And an inclination determination step for determining whether or not directions of the reference graphic and the drawing graphic match,
The graphic determination step includes
When it is determined in the area comparison step that the area of the reference graphic and the area of the drawing graphic are the same, and the rough shape of the reference graphic and the drawing graphic are determined to be similar in the approximate shape determination step And when determining that the orientation of the reference graphic and the drawing graphic match in the inclination determination step, determine that the reference graphic and the drawing graphic match,
When it is determined in the area comparison step that the area of the reference graphic and the area of the drawing graphic are not the same, when it is determined that the reference graphic and the outline of the drawing graphic are not similar in the approximate shape determination step , In at least one of the cases where it is determined that the orientation of the reference graphic and the drawing graphic do not match in the inclination determination step, it is determined that the reference graphic and the drawing graphic do not match.
An image evaluation method characterized by the above. The image evaluation method according to claim 2,
An inclination determination necessity determination step for determining whether or not the reference graphic and the drawing graphic are circular,
When it is determined that the reference graphic and the drawing graphic are not circular in the inclination determination necessity determination step, the inclination determination step is performed.
If it is determined in the determination necessity determination step that either the reference graphic or the drawing graphic is circular, the inclination determination step is not performed.
An image evaluation method characterized by the above. In the image evaluation method according to any one of claims 1 to 3,
The reference figure is a figure on imaging data obtained by imaging a drawing figure previously drawn on a photomask as the comparison reference;
An image evaluation method characterized by the above. In the image evaluation method according to any one of claims 1 to 3,
The reference figure is a figure obtained by simulation drawing on a photomask using design data as the comparison reference;
An image evaluation method characterized by the above. In the image evaluation method according to any one of claims 1 to 5,
The drawing figure length / short ratio calculating step includes:
A point sequence calculating step for calculating a sequence of points constituting the contour line of the drawing figure;
A principal component analysis is performed on the point sequence calculated in the point sequence calculation step to calculate a covariance matrix, and a first principal component and a second principal component of the drawing figure orthogonal to each other obtained by eigenvalue decomposition of the covariance matrix are obtained. The eigenvalues λ1 and λ2 (where λ1 ≧ λ2) of the components are calculated, and the square root (λ1 / λ2) ^1/2 of the ratio λ1 / λ2 of the two eigenvalues λ1 and λ2 is calculated as the ratio of the drawn figure length / shortness. Eigenvalue ratio calculation step;
Providing
An image evaluation method characterized by the above. An image evaluation program for comparing a drawing figure drawn on a photomask with a reference figure that is a comparison reference of the drawing figure,
Computer
The first principal component and the second principal component obtained by principal component analysis of the area of the reference graphic, the outline of the reference graphic, the length of the first principal component and the second main component of the outline of the reference graphic Reference graphic data storage means for storing data relating to a reference graphic length / short ratio which is a ratio of component lengths;
A drawing figure area calculating unit that performs image processing on imaging data of the drawing figure and calculates an area of the drawing figure;
The imaging data of the drawing figure is subjected to image processing, the outline of the drawing figure is subjected to principal component analysis to calculate the first principal component and the second principal component, and the length of the first principal component of the outline of the drawing figure is calculated. A drawing figure length / shortness ratio calculating means for calculating a drawing figure length / shortness ratio, which is a ratio between the length and the length of the second main component;
An area comparison means for comparing the area of the reference graphic stored by the reference graphic data storage means and the area of the drawing graphic calculated by the drawing graphic area calculation means to determine whether or not they are the same;
Based on the ratio between the reference figure length / shortness ratio stored in the reference figure data storage means and the drawing figure length / shortness ratio calculated by the drawing figure length / shortness ratio calculation means, the rough shapes of the reference figure and the drawing figure are similar. Approximate shape determination means for determining whether or not
Function as graphic determination means for determining whether or not the reference graphic and the drawing graphic match,
The graphic determination means,
When the outline similarity determination means determines that the reference figure and the outline of the drawing figure are similar, the area comparison means determines that the area of the reference figure and the area of the drawing figure are the same The reference figure and the drawing figure match,
When the outline similarity determination means determines that the outline of the reference figure and the drawing figure are not similar, and the area comparison means determines that the area of the reference figure and the area of the drawing figure are not the same In at least one case, functioning to determine that the reference graphic and the drawing graphic are inconsistent;
An image evaluation program characterized by The image evaluation program according to claim 7,
The computer,
The direction of the axis of the first principal component of the reference graphic stored in the reference graphic data storage means is compared with the direction of the axis of the first principal component of the drawing graphic calculated by the drawing graphic length / shortness ratio calculating means. , Functioning as an inclination determination means for determining whether or not the orientations of the reference graphic and the drawing graphic match,
The graphic determination means,
When the outline similarity determination means determines that the outlines of the reference figure and the drawing figure are similar, and when it is determined that the orientations of the reference figure and the drawing figure match, and the area comparison means Is determined that the area of the reference graphic and the area of the drawing graphic are the same, it is determined that the reference graphic and the drawing graphic match,
When the outline similarity determination means determines that the outline of the reference figure and the drawing figure are not similar, when it is determined that the orientations of the reference figure and the drawing figure do not match, and the area comparison means In at least one case of determining that the area of the reference graphic and the area of the drawing graphic are not the same, functioning to determine that the reference graphic and the drawing graphic do not match;
An image evaluation program characterized by The image evaluation program according to claim 8,
The computer,
Function as an inclination determination necessity determination unit that determines whether or not both the reference graphic and the drawing graphic are circular,
The inclination determination necessity determination means,
If it is determined that the reference graphic and the drawing graphic are not circular or substantially circular, the inclination determination means determines whether or not the rough shape of the reference graphic and the drawing graphic is similar,
When it is determined that one of the reference graphic and the drawing graphic is circular or substantially circular, the inclination determination unit does not determine whether the directions of the reference graphic and the drawing graphic match. To make it work,
An image evaluation program characterized by In the image evaluation program according to any one of claims 7 to 9,
The drawing figure length / shortness ratio calculating means includes:
Point sequence calculating means for calculating a sequence of points constituting the outline of the drawing figure;
A principal component analysis is performed on the point sequence calculated by the point sequence calculation means to calculate a covariance matrix, and a first principal component and a second principal component of the drawing figure orthogonal to each other obtained by eigenvalue decomposition of the covariance matrix. Eigenvalues λ1, λ2 (where λ1 ≧ λ2) are calculated, and the square root (λ1 / λ2) ^1/2 of the ratio λ1 / λ2 of the two eigenvalues λ1, λ2 is calculated as the ratio of the drawn figure length to the short Function as a ratio calculation means,
An image evaluation program characterized by Of the conditions for drawing a drawing figure equal to the reference figure on the photomask, the outline similarity condition which is a condition affecting whether the outline of the drawing figure is similar to the outline of the reference figure, and A drawing condition selection method for selecting an area condition that affects an area of the drawing figure while maintaining a similar shape to a reference figure.
The first principal component and the second principal component obtained by principal component analysis of the area of the reference graphic, the outline of the reference graphic, the length of the first principal component and the second main component of the outline of the reference graphic A reference graphic data storage step for storing data relating to a reference graphic length / short ratio which is a ratio of component lengths;
A plurality of drawing similarities are set to draw a plurality of drawing figures, image data of the plurality of drawing figures is subjected to image processing, and contour lines of the plurality of drawing figures are subjected to principal component analysis. One principal component and a second principal component are calculated, and the drawing figure length-to-short ratio of the plurality of drawing figures, which is the ratio of the length of the first principal component and the length of the second principal component of the contour lines of the plurality of drawing figures A drawing figure length / short ratio calculation step for calculating
Based on the ratio of the reference figure length / shortness ratio stored in the reference figure data storage step and the drawing figure length / shortness ratio of the plurality of drawing figures calculated in the drawing figure length / shortness ratio calculating step, the reference figure and the plurality of An approximate similarity determination step for determining whether or not the outline of the drawn figure is similar;
An outline for selecting a condition in which the outline of the drawn figure is most similar to the outline of the reference figure from among the plurality of outline similarity conditions by the drawing figure length / shortness ratio calculating step and the outline similarity determining step A similar condition selection step;
Set the outline similarity condition selected in the outline similarity condition selection step, set a plurality of area conditions, draw a plurality of drawing figures, image processing the imaging data of the plurality of drawing figures, A drawing figure area calculating step for calculating an area of the plurality of drawing figures;
An area comparison step of comparing the area of the reference graphic stored in the reference graphic data storage step with the area of the plurality of drawing graphics calculated in the drawing graphic area calculation step to determine whether or not they are the same ,
By performing the drawing figure area calculation step and the area comparison step, an area condition selection step for selecting a condition where the area of the drawing figure is closest to the area of the reference figure,
A drawing condition selection step for selecting, as an optimum condition, a combination of the outline similarity condition selected in the outline similarity condition selection step and the area condition selected in the area condition selection step;
Providing
The drawing condition selection method characterized by this. The drawing condition selection method according to claim 11,
Selecting a backscattering parameter amount as the approximate similarity condition;
The drawing condition selection method characterized by this. The drawing condition selection method according to claim 11 or 12,
Selecting the dose as the area condition;
The drawing condition selection method characterized by this. In the drawing condition selection method according to any one of claims 11 to 13,
The outline similar condition selection step includes:
After the approximate shape determination step, the orientation of the axis of the first principal component of the reference graphic stored in the reference graphic data storage step and the first of the plurality of drawing figures calculated in the drawing figure length / shortness ratio calculation step Compare the orientation of the axis of the principal component, and perform an inclination determination step for determining whether or not the inclinations of the reference graphic and the plurality of drawing figures match,
Based on the results of the approximate similarity determination step and the inclination determination step, a condition in which the approximate shape of the drawn graphic is most similar to the approximate shape of the reference graphic is selected from the plurality of approximate similarity conditions. ,
The drawing condition selection method characterized by this. Of the conditions for drawing a drawing figure equal to the reference figure on the photomask, the outline similarity condition which is a condition affecting whether the outline of the drawing figure is similar to the outline of the reference figure, and A drawing condition selection program that selects an area condition that affects the area of the drawing figure while maintaining the similarity of the outline with the reference figure,
Computer
The first principal component and the second principal component obtained by principal component analysis of the area of the reference graphic, the outline of the reference graphic, the length of the first principal component and the second main component of the outline of the reference graphic A reference graphic data storage means for storing data relating to a reference graphic length / short ratio which is a ratio of component lengths;
A plurality of drawing similarities are set to draw a plurality of drawing figures, image data of the plurality of drawing figures is subjected to image processing, and contour lines of the plurality of drawing figures are subjected to principal component analysis. One principal component and a second principal component are calculated, and the drawing figure length-to-short ratio of the plurality of drawing figures, which is the ratio of the length of the first principal component and the length of the second principal component of the contour lines of the plurality of drawing figures A drawing figure length / short ratio calculating means for calculating
Based on the ratio between the reference figure length / shortness ratio stored in the reference figure data storage means and the drawing figure length / shortness ratio of the plurality of drawing figures calculated by the drawing figure length / shortness ratio calculating means, the reference figure and the plurality of the plurality of drawing figures A rough similarity determination means for determining whether the rough shapes of the drawn figures are similar;
By performing the drawing figure length / shortness ratio calculating means and the approximate similarity determination means, a condition in which the outline of the drawing figure is most similar to the outline of the reference figure among the plurality of outline similarity conditions A rough similarity condition selection means to select;
The outline similarity condition selected by the outline similarity condition selection unit is set, a plurality of area conditions are set, a plurality of drawing figures are drawn, and imaging data of the plurality of drawing figures is image-processed, A drawing figure area calculating means for calculating an area of the plurality of drawing figures;
An area comparison means for comparing the area of the reference graphic stored in the reference graphic data storage means and the area of the plurality of drawing figures issued by the drawing figure area calculating means to determine whether or not they are the same ,
By performing the drawing figure area calculation means and the area comparison means, an area condition selection means for selecting a condition in which the area of the drawing figure is closest to the area of the reference figure,
Functioning as a drawing condition selection means for selecting a combination of the outline similarity condition selected by the outline similarity condition selection means and the area condition selected by the area condition selection means as an optimum condition;
A drawing condition selection program characterized by

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