JP4008934B2 - Image data correction method, lithography simulation method, program, and mask - Google Patents

Description

  The present invention relates to a method for correcting image data, a lithography simulation method, and the like.

  As semiconductor devices are highly integrated and miniaturized, it has become important to predict lithography tolerance with high accuracy from a mask pattern actually formed on a photomask.

  As a method of predicting the lithography tolerance from the actual finished shape of the mask, in Patent Document 1, a mask pattern image is acquired by SEM, the contour of the acquired image pattern is extracted, and lithography simulation is performed using the contour data. A method has been proposed.

  The image of the mask pattern can be acquired by an image acquisition device such as a scanning electron microscope (SEM). However, since image distortion generally exists in an image acquisition device, it is difficult to faithfully acquire a fine pattern image. For example, in SEM, there is image distortion due to distortion of the scan beam. The problem is that the edge position error of the contour data extracted from the image having distortion greatly affects the lithography simulation result.

  As a method for correcting image distortion, Patent Document 2 proposes a method in which correction data is obtained in advance from image data of a reference pattern and the image data of a target pattern is corrected using the correction data. Has been.

However, in the conventional method, the image data of the entire target pattern is corrected, so that the amount of data becomes enormous and the correction calculation requires a lot of time. Therefore, conventionally, it has been difficult to correct an image pattern with a small amount of data at high speed and with high accuracy.
JP 2004-37579 A Japanese Patent No. 2687781

  An object of the present invention is to provide an image data correction method, a lithography simulation method, and the like that can correct an image pattern with a small amount of data at high speed and with high accuracy.

  The image data correction method according to the present invention includes a step of preparing correction data for correcting distortion of an image obtained by an image acquisition unit, and a step of acquiring contour data of a desired pattern obtained by the image acquisition unit. And correcting the contour data of the desired pattern using the correction data.

  The lithography simulation method according to the present invention includes a step of preparing correction data for correcting distortion of an image obtained by an image obtaining unit, a step of obtaining contour data of a desired pattern obtained by the image obtaining unit, A step of correcting the contour data of the desired pattern using the correction data, and a step of performing a lithography simulation for the desired pattern using the corrected contour data.

  The program according to the present invention includes a procedure for obtaining correction data for correcting distortion of an image obtained by an image obtaining unit, a procedure for obtaining contour data of a desired pattern obtained by the image obtaining unit, and the correction. And a procedure for correcting the contour data of the desired pattern using the data.

  The mask according to the present invention includes a desired pattern and a test pattern used for calculating correction data for correcting the contour data of the desired pattern obtained by the image acquisition unit.

  According to the present invention, by correcting the contour data, it is possible to correct the image distortion of the desired pattern with a small amount of data at high speed and with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is an explanatory diagram for explaining a configuration of an image data correction system according to the first embodiment of the present invention.

  The image acquisition unit (image acquisition device) 10 is configured by a scanning electron microscope (SEM). In the image acquisition unit 10, an electron beam from the electron beam supply unit 11 is irradiated onto the photomask 13 placed on the stage 12, and the electron beam reflected on the surface of the photomask 13 is detected by the detection unit 14. Thus, an image of the pattern formed on the photomask 13 is acquired. The detected image information is supplied to the computer 20 via the signal amplifier 15.

  An operation unit 21 (such as a keyboard) for giving instructions to the computer 20 and an image display unit 22 (such as a CRT) that displays images acquired by the image acquisition unit 10 are connected to the computer 20.

  The image data storage unit 31 stores image data of the image acquired by the image acquisition unit 10. When the photomask 13 actually used when forming a semiconductor device such as an LSI is placed on the stage 12, a device pattern (a desired pattern such as a wiring pattern or a contact hole pattern formed on the photomask 13). Pattern) image data is stored in the image data storage unit 31. Further, when the photomask 13 on which the reference pattern for creating correction data is formed is placed on the stage 12, the image data of the reference pattern is stored in the image data storage unit 31.

  The contour data storage unit 32 stores the above-described device pattern contour data. The contour data is extracted by performing predetermined processing on the image data stored in the image data storage unit 31.

  The correction data storage unit 33 stores correction data for correcting image distortion obtained by the image acquisition unit 10. The correction data is created by performing the processing described later using the above-described reference pattern image data.

  The corrected contour data storage unit 34 stores contour data whose image distortion has been corrected. By correcting the contour data stored in the contour data storage unit 32 using the correction data stored in the correction data storage unit 33, corrected contour data in which image distortion is corrected is obtained.

  The lithography condition storage unit 35 stores data on lithography conditions when forming a photoresist pattern by transferring a device pattern formed on a photomask to a photoresist on a semiconductor wafer.

  The simulation data storage unit 36 stores the result of the lithography simulation performed using the corrected contour data stored in the corrected contour data storage unit 34 and the lithography condition data stored in the lithography condition storage unit 35. Is. The simulation result obtained by the lithography simulation includes a prediction result of the lithography tolerance when the above-described photoresist pattern is formed.

  The above-described various data creation processing, lithography simulation, and the like are executed by the computer 20.

  Next, processing performed using the system shown in FIG. 1 will be described with reference to the flowchart shown in FIG.

  First, the photomask on which the reference pattern is formed is placed on the stage 12 in the image acquisition unit 10 to acquire image data of the reference pattern (S11). The image acquisition conditions are an acceleration voltage of 1500 V, a sample current of 8 pA, a pixel count of 2048 × 2048, and a magnification of 20000 times. As the reference pattern, a line and space (L / S) pattern having a constant line width and space width is used as shown in FIG. The image data of the reference pattern acquired by the image acquisition unit 10 is sent to the computer 20, and contour data (edge data) is calculated.

  Subsequently, the number of pixels included in one pitch of the line and space pattern is calculated from the obtained contour data. For periodic patterns such as L / S on a photomask, even if the line width (Wl) and space width (Ws) vary in size depending on the location, one pitch of the line-and-space pattern is constant with relatively high accuracy. It is finished. For this reason, if the image obtained by the image acquisition unit 10 is not distorted, the number of pixels included in one pitch of the line and space pattern (the width of one pitch is Wl + Ws) is considered to be constant regardless of the location. However, since image distortion always exists in the actual image acquisition unit 10, the number of pixels included in one pitch of the line and space pattern varies depending on the location. Accordingly, by obtaining the in-plane distribution of the number of pixels included in one pitch, the in-plane distribution of the pixel size can be obtained. In the present embodiment, the in-plane distribution of the pixel size is represented by the following quadratic curved surface approximation formula (1).

Psx = Ax + Bx · X + Cx · Y + Dx · X 2 + Ex · X · Y + Fx · Y 2
Psy = Ay + By.X + Cy.Y + Dy.X ² + Ey.X.Y + Fy.Y ² (1)
However, Psx is the pixel size in the X direction at the coordinates (X, Y), Psy is the pixel size in the Y direction at the coordinates (X, Y), and Ax, Bx, Cx, Dx, Ex, Fx, Ay, By, Cy, Dy, Ey and Fy are coefficients.

  In the present embodiment, coefficients as shown in FIG. 4 are obtained from the measurement results obtained as described above. Further, the in-plane distribution of the pixel size based on the quadratic curved surface approximation formula is as shown in FIG. In FIG. 5A, a region A1 is a pixel distribution region where the pixel size in the X direction is in the range of 1.02 to 1.03, and a region A2 is a pixel size in the X direction of 1.01 to 1.02. The pixel distribution region in the range of A, the region A3 is the pixel distribution region in the range of the pixel size in the X direction from 1.00 to 1.01, and the region A4 is the pixel size in the X direction of 0.99 to 1.00 The distribution area of the pixels in the range is shown. In FIG. 5B, a region B1 is a pixel distribution region where the pixel size in the Y direction is in the range of 0.89 to 0.90, and a region B2 is a range where the pixel size in the Y direction is from 0.88 to 0.89. The pixel distribution region B3 is a pixel distribution region in which the pixel size in the Y direction is in the range of 0.87 to 0.88.

  In this way, correction data for correcting the distortion of the image obtained by the image acquisition unit 10 is calculated (S12). The calculated correction data is stored in the correction data storage unit 33.

  Next, a process of performing a lithography simulation using device pattern contour data used when forming a semiconductor device such as an LSI will be described.

  First, a photomask on which a device pattern such as a wiring pattern or a contact hole pattern is formed is placed on the stage 12 in the image acquisition unit 10 to acquire device pattern image data (S21). The image acquisition conditions are an acceleration voltage of 1500 V, a sample current of 8 pA, a pixel count of 2048 × 2048, and a magnification of 20000 times. Here, it is assumed that a device pattern as shown in FIG. 6 is formed on a photomask.

  The device pattern image data acquired by the image acquisition unit 10 is sent to the computer 20, and contour data (edge data) is extracted (S22). The threshold value method is used for extracting the contour, and the threshold value is set to 50%, for example. The number of XY coordinates output as a result of contour extraction is 36000. The obtained contour data is sent to the contour data storage unit 32.

  Next, the contour data is corrected using the correction data stored in the correction data storage unit 33 (S23). Thereby, contour data in which image distortion caused by the image acquisition unit 10 is corrected is obtained. Specifically, the corrected contour data is obtained by rearranging the contour data stored in the contour data storage unit 32 using the correction data. The corrected contour data is stored in the corrected contour data storage unit 34.

  In the present embodiment, the contour (edge) of the pattern is extracted and the extracted contour is corrected. Therefore, the calculation time spent for the correction process can be greatly shortened, and the storage capacity for storing the correction result can be greatly reduced. In the present embodiment, the total number of pixels is 2048 × 2048. Therefore, if correction is performed for the pixels of the entire pattern, 2048 × 2048 correction calculations are required in the X direction and the Y direction, respectively. On the other hand, when the contour is corrected as in the present embodiment, it is only necessary to correct the portion where the contour is extracted. Therefore, the correction calculation may be performed 36000 times in the X direction and the Y direction. Further, since it is only necessary to store data for the portion where the contour has been extracted, the storage capacity for storing data is greatly reduced.

  Next, lithography simulation is performed using the corrected contour data obtained as described above (S24).

  FIG. 7 shows an image intensity profile obtained by simulation. Line a is the image intensity when the contour correction is not performed, line b is the image intensity when the XY magnification correction is performed, line c is the image intensity when the contour correction is performed (the method of this embodiment), and line d is This is the image intensity when using mask design data (corresponding to the assumption that there is no image distortion). P1 to P7 indicate the positions of the patterns shown in FIG.

  FIG. 8 shows the intensity difference at the peak value of each line shown in FIG. The lines a, b, and c shown in FIG. 8 correspond to the intensity difference between the lines a and d, the intensity difference between the lines b and d, and the intensity difference between the lines c and d shown in FIG. is doing.

  As can be seen from FIGS. 7 and 8, when the contour correction is not performed (line a in FIGS. 7 and 8) and when the XY magnification correction is performed (line b in FIGS. 7 and 8), the mask design data is stored. The difference in image intensity with respect to the use is large. In particular, the image intensity difference increases toward the outside of the image. This is because an error has occurred in the contour position due to the influence of image distortion generated in the image acquisition unit 10.

  On the other hand, when contour correction is performed by the method of the present embodiment (line c in FIGS. 7 and 8), the image intensity difference with respect to the mask design data is small. Further, the image intensity difference is almost constant regardless of the image position. This is because when the contour correction is performed by the method of the present embodiment, the influence of the image distortion is greatly reduced and the contour position error becomes very small. Therefore, it is possible to accurately predict the lithography tolerance by performing lithography simulation using data that has been subjected to contour correction by the method of the present embodiment.

  Note that at least a part of the method of the present embodiment described above can be provided by a program capable of executing the procedure of the method described above by a computer.

  As described above, according to the present embodiment, the contour of the pattern obtained by the image acquisition unit is extracted, and correction processing for correcting image distortion is performed on the extracted contour. Therefore, the amount of data necessary for the correction process can be greatly reduced. As a result, the calculation time can be greatly reduced and the data storage capacity can be greatly reduced. Further, even if the data amount is greatly reduced, image distortion can be corrected with high accuracy, and a pattern can be acquired with high accuracy.

  In the above-described embodiment, the relationship between the magnification and the image distortion of the image acquisition unit is not particularly mentioned. However, as described below, the image distortion is corrected in consideration of the relationship between the magnification and the image distortion. You may make it perform.

  In an image acquisition unit such as a scanning electron microscope, the state of image distortion changes as the magnification changes. FIG. 9 shows a distribution of pixel sizes when the magnification is 10,000 times (10k times). FIG. 9A shows the distribution of pixel sizes in the X direction, and FIG. 9B shows the distribution of pixel sizes in the Y direction. Compared with the case of FIG. 5 (magnification 20000 times (20k times)), it can be seen that the distribution of the pixel size changes.

  As described above, when the magnification of the image acquisition unit changes, the state of image distortion also changes. Therefore, the coefficient of the quadratic curved surface approximation equation described above also changes depending on the magnification. FIG. 10 is a diagram showing the relationship between the magnification and the coefficients Ax, Bx, Cx, Dx, Ex, Fx, Ay, By, Cy, Dy, Ey, and Fy. By storing the relationship as shown in FIG. 10 as a correction table, it is possible to perform an appropriate correction according to the magnification.

  In the above-described embodiment, the relationship between the occupancy ratio of the pattern included in the image acquired by the image acquisition unit and the image distortion is not particularly mentioned. However, as described below, the pattern occupancy ratio and the image distortion are described. The image distortion may be corrected in consideration of the relationship between the

  For example, the pattern occupation ratio (pattern coverage on the photomask) differs between the pattern shown in FIG. 11 and the pattern shown in FIG. When the pattern coverage is different, the surface potential of the photomask when the image is acquired by the image acquisition unit (electron microscope) is different. Therefore, the image distortion state may change.

  Thus, since the state of image distortion changes as the pattern coverage changes, the coefficients of the quadratic surface approximation formula described above also change depending on the pattern coverage. Therefore, as in the case of the magnification, by storing the relationship between the pattern coverage and the coefficient as a correction table, it is possible to perform appropriate correction according to the pattern coverage (pattern occupancy).

  In addition, it is conceivable that the state of image distortion changes depending on the focus position during pattern observation. In this case as well, a correction table corresponding to the focus position may be prepared, and correction corresponding to the focus position during desired pattern observation may be performed.

  In the above-described embodiment, the photomask has been described as an example of the measurement target. However, the same method as in the above-described embodiment can be applied even when an EUV exposure mask or an EB exposure mask is used. It is. In the above-described embodiment, the scanning electron microscope is used as the image acquisition unit (image acquisition device). However, an image acquisition device other than the scanning electron microscope may be used.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. The basic system configuration (see FIG. 1) and the basic method are the same as those in the first embodiment. Therefore, unless otherwise specified, the matters described in the first embodiment can be applied to this embodiment.

  FIG. 12 is a flowchart showing the method of this embodiment.

  First, a photomask on which a reference pattern is formed is prepared, and image measurement of the reference pattern is performed by an image acquisition unit (SEM or the like). The measurement result is stored in the data storage unit as a reference image measurement result. Further, a reference image distortion coefficient is calculated from the measurement result and stored in the data storage unit (S51). The reference image distortion coefficient includes, for example, the coefficients Ax, Bx, Cx, Dx, Ex, Fx, Ay, By, Cy, Dy, Ey, and Fy shown in Expression (1) of the first embodiment. .

  Next, a photomask on which a device pattern (desired pattern) and a test pattern are formed is prepared, and the image of the test pattern is measured by the image acquisition unit (S52).

  For example, when the coverage (occupancy) of the device pattern formed on the photomask is different, the surface potential of the photomask when the image is acquired by the image acquisition unit (SEM) is also different. Therefore, the image distortion state may change. Also, the thickness of the photomask substrate generally varies. Therefore, there is a possibility that the focus position is shifted, a magnification error occurs, and the image distortion state changes. As described above, the image acquired by the image acquisition unit may include distortion due to the photomask. Therefore, in the present embodiment, a test pattern is formed on a photomask on which a device pattern is formed, and distortion caused by the photomask is corrected using this test pattern.

  FIG. 13 is a diagram schematically showing a photomask on which a device pattern and a test pattern are formed. A device pattern 53 is formed in the exposure area 51 of the photomask 50, and a test pattern portion 54, an alignment mark 55, and the like are formed in the non-exposure area 52 of the photomask 50.

  FIG. 14 and FIG. 15 are diagrams showing examples of test patterns arranged in the test pattern portion 54. The test pattern shown in FIG. 14 is the same pattern as that used when obtaining the reference image distortion coefficient, and is mainly used for correcting the magnification error of the device pattern 53. The test pattern shown in FIG. 15 is mainly used for correcting an error based on the coverage of the device pattern 53. Either one of the test patterns shown in FIGS. 14 and 15 may be formed on the test pattern portion 54, or both may be formed on the test pattern portion 54. FIG. 16 is a diagram showing the distortion measurement result of the test pattern shown in FIG. 14, and FIG. 17 is a diagram showing the distortion measurement result of the test pattern shown in FIG. A solid line indicates a lattice based on the measurement result, and a broken line indicates a lattice based on the design data.

  The test pattern shown in FIG. 15 desirably has a coverage equivalent to the coverage (a ratio of the light shielding portion) in a predetermined region of the device pattern 53. The predetermined area may be the entire area where the device pattern 53 is formed, or may be an area corresponding to the observation area of the image acquisition unit. In this case, it is desirable that the pattern of the test pattern portion 54 is substantially the same pattern as the pattern of the device pattern 53. However, the device pattern 53 is normally subjected to optical proximity effect correction (OPC). A pattern subjected to OPC generally has a complicated shape. For this reason, if a pattern subjected to OPC is used for the test pattern portion 54, image distortion measurement becomes complicated. Therefore, it is desirable to use a pattern not subjected to OPC for the test pattern portion 54. Since the image acquisition locations in the device pattern 53 have already been determined at the time of mask pattern design, a plurality of test patterns can be arranged according to the coverage of each image acquisition location.

  After performing the test pattern image measurement using the test pattern unit 54 as described above, the test pattern image measurement result is compared with the reference image measurement result stored in the data storage unit (S53). Further, it is determined whether or not the comparison result satisfies a predetermined condition (S54). For example, it is determined whether or not the error of the test pattern image measurement result with respect to the reference image measurement result is within a predetermined range.

  For example, the case where the test pattern shown in FIG. 14 is used is assumed. In this case, the image acquisition unit uses a photomask in which the same pattern as that shown in FIG. 14 is formed as a reference pattern (a photomask for acquiring a reference pattern image different from the photomask in FIG. 13). A reference pattern image is measured in advance. This measurement result is stored in the data storage unit as the reference image measurement result in step S51. The image of the reference pattern acquired by the image acquisition unit also includes image distortion. An error based on this distortion (an error with respect to the design data) is expressed by Expression (2).

Ex (j) = Mx × X (j) − (Rot + Skew) × Y (j)
Ey (j) = My × Y (j) + Rot × X (j) (2)
Ex (j) and Ey (j) are the errors in the X and Y directions at point j, respectively. X (j) and Y (j) indicate the positions of the j point in the X direction and the Y direction, respectively. Mx and My are error components in the X and Y directions related to the magnification, respectively. Rot and Skew are error components related to rotation and skew, respectively.

  At the same time, a correction coefficient for correcting the in-plane distribution of the pixel size obtained in steps S11 to S12 described in the first embodiment is also stored in the data storage unit as a reference image distortion coefficient.

  For the photomask on which the test pattern portion 54 is formed (the photomask in FIG. 13), errors Ex (j) ′ and Ey (j) ′ with respect to the design data are obtained in the same manner as described above, and the error component Mx ′. , My ′, Rot ′ and Skew ′.

  If it is determined in step S54 that the predetermined condition is satisfied, steps S61 to S64 are executed. The basic processing performed in steps S61 to S64 is the same as the processing described in S21 to S24 of the first embodiment. That is, the image of the device pattern 53 formed on the photomask 50 is acquired by the image acquisition unit (S61). Subsequently, contour data (edge data) is extracted from the acquired image (S62). Further, the contour data is corrected using the reference image distortion coefficient (correction data) stored in the data storage unit (S63). A lithography simulation is performed using the corrected contour data thus obtained (S64).

  If it is determined in step S54 that the predetermined condition is not satisfied, steps S71 to S75 are executed. The basic processing performed in steps S71 to S75 is the same as the processing described in S21 to S24 of the first embodiment. However, in steps S71 to S75, correction reflecting the test pattern image measurement result is performed.

First, a distortion correction coefficient is calculated based on the test pattern image measurement result (S71). Here, as described above, since the error components Mx ′ and My ′ relating to the magnification obtained in the step of S52 did not satisfy the predetermined condition in the step of S54, the distortion measurement pattern image measurement of the test pattern unit 54 for the magnification correction is performed. A case where the result is reflected will be described. In this case, the expression (1) of the first embodiment is Psx ′ = (1 + Mx ′) × Psx
Psy ′ = (1 + My ′) × Psy (3)
It is expressed. That is, the coefficients Ax, Bx, Cx, Dx, Ex, and Fx in the equation (1) are multiplied by (1 + Mx ′), and the coefficients Ay, By, Cy, Dy, Ey, and Fy are multiplied by (1 + My ′). These (1 + Mx ′) times or (1 + My ′) times of coefficients become distortion correction coefficients.

  After calculating the distortion correction coefficient in this way, an image of the device pattern 53 formed on the photomask 50 is acquired by the image acquisition unit (S72). Subsequently, contour data (edge data) is extracted from the acquired image (S73). Further, the contour data is corrected using the distortion correction coefficient (correction data) calculated in step S71 (S74). A lithography simulation is performed using the corrected contour data thus obtained (S75).

  When correcting the error based on the coverage of the device pattern 53, the distortion measurement result (FIG. 17) of the distortion measurement pattern shown in FIG. 15 having the same coverage as the image acquisition unit is reflected in step S71. Just do it.

  As described above, also in the present embodiment, as in the first embodiment, the contour of the pattern obtained by the image acquisition unit is extracted, and the correction process for correcting the image distortion with respect to the extracted contour is performed. Do. Therefore, as in the first embodiment, the amount of data necessary for the correction process can be greatly reduced. As a result, the calculation time can be greatly reduced and the data storage capacity can be greatly reduced. Further, even if the data amount is greatly reduced, image distortion can be corrected with high accuracy, and a pattern can be acquired with high accuracy.

  In the present embodiment, the test pattern is arranged on the photomask on which the device pattern is arranged. For this reason, it is possible to perform correction in consideration of distortion caused by the photomask, and it is possible to acquire a pattern with higher accuracy.

  FIG. 18 is a flowchart showing an outline of a method for manufacturing a semiconductor device (semiconductor integrated circuit) using the photomask shown in the first and second embodiments. First, a photomask is prepared (S101), and a mask pattern (device pattern) on the photomask is projected onto a photoresist on a wafer (semiconductor substrate) (S102). Subsequently, a photoresist pattern is formed by developing the photoresist (S103). Further, a desired pattern is formed by etching the conductive film, the insulating film, and the like on the semiconductor substrate using the photoresist pattern as a mask (S104).

  The procedure of the method of the first and second embodiments described above can be realized by a computer whose operation is controlled by a program in which the procedure of the method is described. The program can be provided by a recording medium such as a magnetic disk or a communication line (wired line or wireless line) such as the Internet.

  In summary, the image data correction method according to the embodiment of the present invention includes a step of preparing correction data for correcting distortion of an image obtained by the image acquisition unit, and a desired pattern obtained by the image acquisition unit. Obtaining the contour data, and correcting the contour data of the desired pattern using the correction data.

  In the image data correction method, the step of preparing the correction data includes a step of acquiring image data of a reference pattern by the image acquisition unit, and a step of calculating the correction data using the image data of the reference pattern. ,including.

  In the image data correction method, the correction data is based on a distortion distribution of an image obtained by the image acquisition unit.

  In the image data correction method, the correction data depends on a magnification of an image obtained by the image acquisition unit.

  In the image data correction method, the correction data depends on an occupation ratio of a pattern included in an image obtained by the image acquisition unit.

  In the image data correction method, the step of preparing the correction data includes a step of acquiring image data of a test pattern arranged on a mask on which the desired pattern is arranged, and an image of the test pattern. Calculating the correction data using data.

  In the image data correction method, the test pattern is arranged in a non-exposure area outside the exposure area where the desired pattern is arranged.

  In the image data correction method, the test pattern is used to correct a magnification error of the desired pattern acquired by the image acquisition unit.

  In the image data correction method, the test pattern has an occupation ratio corresponding to the occupation ratio of the desired pattern.

  In the image data correction method, when the test pattern image data acquired by the image acquisition unit does not satisfy a predetermined condition, the correction data is calculated using the test pattern image data.

  In the image data correction method, the image acquisition unit includes an electron microscope.

  In a lithography simulation method according to an embodiment of the present invention, a step of preparing correction data for correcting distortion of an image obtained by an image acquisition unit, and contour data of a desired pattern obtained by the image acquisition unit are obtained. A step of correcting the contour data of the desired pattern using the correction data, and a step of performing a lithography simulation for the desired pattern using the corrected contour data.

  An image data correction system according to an embodiment of the present invention includes a correction data storage unit that stores correction data for correcting distortion of an image obtained by an image acquisition unit, and a desired pattern obtained by the image acquisition unit. An outline data storage unit that stores outline data, and a correction unit that corrects the outline data of the desired pattern using the correction data.

  A program according to an embodiment of the present invention includes a procedure for obtaining correction data for correcting distortion of an image obtained by an image obtaining unit, and a procedure for obtaining contour data of a desired pattern obtained by the image obtaining unit. And a procedure for correcting the contour data of the desired pattern using the correction data.

  A mask according to an embodiment of the present invention includes a desired pattern and a test pattern used to calculate correction data for correcting contour data of the desired pattern obtained by an image acquisition unit.

  In the mask, the test pattern is arranged in a non-exposed area outside the exposed area where the desired pattern is arranged.

  A manufacturing method of a semiconductor device according to an embodiment of the present invention includes a step of preparing the mask and a step of projecting the desired pattern arranged on the mask onto a resist film on a semiconductor substrate.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed constituent elements. For example, even if some constituent requirements are deleted from the disclosed constituent requirements, the invention can be extracted as long as a predetermined effect can be obtained.

It is explanatory drawing for demonstrating the structure of the correction system of the image data which concerns on the 1st Embodiment of this invention. 5 is a flowchart for explaining a method of correcting image data according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of a reference pattern according to the first embodiment of the present invention. It is a figure showing an example of a coefficient of an approximate expression used in connection with a 1st embodiment of the present invention as correction data. 6 is a diagram illustrating an example of an in-plane distribution of pixel sizes according to the first embodiment of the present invention. FIG. It is a figure showing an example of a device pattern concerning a 1st embodiment of the present invention. FIG. 5 is a diagram illustrating an example of an image intensity profile obtained by simulation according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of an intensity difference obtained from an image intensity profile according to the first embodiment of the present invention. FIG. 10 is a diagram illustrating another example of the in-plane distribution of pixel sizes according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating another example of coefficients of an approximate expression used as correction data according to the first embodiment of the present invention. FIG. 10 is a diagram illustrating another example of a device pattern according to the first embodiment of the present invention. It is a flowchart for demonstrating the correction method of the image data which concerns on the 2nd Embodiment of this invention. It is the figure which showed the example of the photomask concerning the 2nd Embodiment of this invention. FIG. 10 is a diagram illustrating an example of a test pattern according to the second embodiment of the present invention. FIG. 10 is a diagram illustrating another example of a test pattern according to the second embodiment of the present invention. It is a figure showing a measurement result of a test pattern concerning a 2nd embodiment of the present invention. It is a figure showing a measurement result of a test pattern concerning a 2nd embodiment of the present invention. 5 is a flowchart illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image acquisition part 11 ... Electron beam supply part 12 ... Stage 13 ... Photomask 14 ... Detection part 15 ... Signal amplification part 20 ... Computer 21 ... Operation part 22 ... Image display part 31 ... Image data storage part 32 ... Contour data storage Unit 33 ... Correction data storage unit 34 ... Corrected contour data storage unit 35 ... Lithography condition storage unit 36 ... Simulation data storage unit 50 ... Photomask 51 ... Exposure region 52 ... Non-exposure region 53 ... Device pattern 54 ... Test pattern 55 ... Alignment mark

Claims (4)

Preparing correction data for correcting distortion of the image obtained by the image acquisition unit;
Obtaining contour data of a desired pattern obtained by the image obtaining unit;
Correcting the contour data of the desired pattern using the correction data;
Equipped with a,
The step of preparing the correction data includes a step of acquiring image data of a test pattern arranged on a mask on which the desired pattern is arranged, and a step of acquiring the correction data using the image data of the test pattern. A method of correcting the image data. Preparing correction data for correcting distortion of the image obtained by the image acquisition unit;
Obtaining contour data of a desired pattern obtained by the image obtaining unit;
Correcting the contour data of the desired pattern using the correction data;
Performing lithography simulation on the desired pattern using the corrected contour data;
Equipped with a,
The step of preparing the correction data includes a step of acquiring image data of a test pattern arranged on a mask on which the desired pattern is arranged, and a step of acquiring the correction data using the image data of the test pattern. And a calculating step . A lithography simulation method comprising: A procedure for acquiring correction data for correcting image distortion obtained by the image acquisition unit;
A procedure for acquiring contour data of a desired pattern obtained by the image acquisition unit;
A procedure for correcting the contour data of the desired pattern using the correction data;
A program for causing a computer to execute the,
The procedure of acquiring the correction data includes a procedure of acquiring image data of a test pattern arranged on a mask on which the desired pattern is arranged, and a step of acquiring the correction data using the image data of the test pattern. Including a procedure for calculating
A program characterized by that. The desired pattern,
A test pattern used to calculate correction data for correcting the contour data of the desired pattern obtained by the image acquisition unit;
A mask characterized by comprising.

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