JP2006323023A - Method for forming mask pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a mask pattern, with which increase in a time period for drawing is suppressed and improvement of accuracy in drawing is possible. <P>SOLUTION: A layout data of the mask pattern is acquired, and a first correction map, in which first dimensional correction amounts are respectively set to a plurality of first small regions formed by partitioning the mask pattern arrangement surface in a grid, is formed based on the arrangement of the mask pattern. A second correction map, in which second dimensional correction amounts are respectively set to a plurality of second small regions partitioned in the same grid shape as that of the plurality of first small regions and displaced relative to the first small regions, is formed based on the arrangement of the mask pattern. Then the mask pattern is corrected based on the first and the second correction maps. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for creating a mask pattern for manufacturing a photomask.

  With the miniaturization of circuit patterns of semiconductor devices, a technique for accurately controlling the line width of patterns formed on a semiconductor substrate by a lithography process is required. For the production of a photomask used in the lithography process, a drawing apparatus using an electron beam (EB) or the like is used. For example, a circuit pattern designed based on the layout of a semiconductor device is transferred to a resist film on a mask blank by a drawing device. Using the transfer image of the resist film as a mask, the light shielding film such as chromium (Cr) of the mask blank is removed to manufacture a photomask.

  In some cases, a dimensional variation may occur in the resist pattern transferred from the mask pattern of the photomask to the resist film on the semiconductor substrate by the exposure apparatus. One of the causes that the resist pattern dimension fluctuates is the optical proximity effect (OPE) generated in the exposure process in the exposure apparatus. OPE appears prominently in patterns with dimensions near the resolution limit. The OPE can predict a dimensional variation from a lithography simulation considering a pattern arrangement of a local region of several μm around the target pattern. By the optical proximity effect correction (OPC) that corrects the mask pattern dimension based on the predicted dimension variation, the resist pattern variation can be suppressed.

  In addition, a dimensional variation may occur in the mask pattern transferred onto the photomask. The dimensional variation of the mask pattern becomes the dimensional variation of the circuit pattern of the semiconductor device and adversely affects the operation of the semiconductor device, so it is necessary to suppress it as much as possible.

  Causes of the dimensional variation of the mask pattern include a loading effect generated in the photomask manufacturing process, overexposure due to reflected electrons in the drawing apparatus, and the like. The “loading effect” is a dimensional variation caused by an etching process at the time of creating a photomask, and is a phenomenon that varies depending on a pattern arrangement point, a pattern density distribution, or the like. Due to the loading effect characteristic, the finished dimension of the mask pattern varies globally. “Global” refers to a range of about 1 mm to several tens of mm of the photomask. That is, the finished size of the mask pattern varies gently over almost the entire area of the photomask.

  In response to mask pattern dimensional variations caused by pattern density, the mask pattern transferred to the photomask is divided into small areas, and the mask patterns belonging to the small areas are extracted, and the mask patterns are arranged in the small areas. A method of correcting with a different dimensional correction amount according to the pattern density is used (for example, see Patent Document 1). Here, the small area group on the surface corresponding to the photomask surface is referred to as a “map”. The small region is, for example, one that is divided into a grid pattern vertically and horizontally.

For example, if each mask pattern divided by adjacent small regions in the map is corrected with a different dimensional correction amount according to the pattern density, a minute figure less than the threshold of the drawing apparatus may be generated. It has been pointed out that when drawing is performed with a vector-type EB drawing apparatus, minute figures generated by the correction are not resolved, and the drawing accuracy of the mask pattern deteriorates. In addition, the generation of minute figures increases the drawing data, resulting in an increase in drawing time. In addition, high precision is required for the gate pattern of a metal / oxide film / semiconductor (MOS) transistor. In the case where a small area is included between mask patterns that require high accuracy, there is a problem in the accuracy of linking between shots by rectangular division or trapezoid division of EB drawing.
Japanese Unexamined Patent Publication No. 2000-75467 (page 3-4, FIG. 1)

  An object of the present invention is to provide a mask pattern creation method capable of suppressing an increase in drawing time and improving drawing accuracy.

  According to the first aspect of the present invention, (a) the map creating unit uses the first pattern based on the mask pattern layout in each of the plurality of first small areas obtained by dividing the mask pattern layout surface in a grid pattern. A first correction map in which a dimensional correction amount is set is created, and (b) a map creation unit masks each of a plurality of second small regions whose boundary positions are shifted with respect to the plurality of first small regions. Creating a second correction map in which a second dimensional correction amount is set based on the arrangement of the patterns, and (c) correcting the mask pattern based on the first and second correction maps by the correction unit. A mask pattern creation method is provided.

  According to the second aspect of the present invention, (a) obtaining a mask pattern subjected to optical proximity correction based on calculation of an optical image of an exposure apparatus that transfers a photomask pattern to a resist film on a semiconductor substrate. And (b) a first correction in which a first dimensional correction amount is set based on the mask pattern arrangement in each of a plurality of first small areas obtained by dividing the mask pattern arrangement surface in a grid pattern by the correction unit. A second correction map in which a second dimensional correction amount is set based on the arrangement of the mask pattern in each of a map and a plurality of second small areas whose boundary positions are shifted with respect to the plurality of first small areas And (c) by the search unit, one of the two line segments forming a right angle is less than the minimum step length by the optical proximity effect correction, and (c) the search unit generates a correction pattern by correcting the mask pattern. 2 segments The risky figure whose line segment length is less than the threshold value based on the minimum shot size for drawing the mask pattern on the photomask substrate is searched, and (d) the threshold value included in the correction pattern in the risky figure by the graphic processing unit There is provided a mask pattern generation method including removing a minute pattern.

  According to the present invention, it is possible to provide a mask pattern creation method capable of suppressing an increase in drawing time and improving drawing accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the configuration of the apparatus and system is different from the actual one. Therefore, a specific configuration should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different structures and the like are included between the drawings.

  As shown in FIG. 1, the mask pattern creation system according to the embodiment of the present invention includes a pattern creation unit 10, an external storage device 20, an input device 22, an output device 24, an external storage device 20, a drawing system 50, and the like. Prepare. The pattern creation unit 10 includes an input unit 30, a map creation unit 32, a correction unit 34, a synthesis unit 36, a search unit 38, a graphic processing unit 40, a data conversion unit 42, an output unit 44, an internal memory 46, and the like. .

  The pattern creation unit 10 acquires the layout data of the mask pattern. A first correction map in which a first dimensional correction amount is set based on the arrangement of the mask pattern in each of a plurality of first small areas obtained by dividing the mask pattern arrangement surface in a grid pattern; and a plurality of first small areas A second dimensional correction amount is set based on the arrangement of the mask pattern in each of a plurality of second small regions that are partitioned in the same grid as the region and shifted in position relative to the first small region. Create a correction map. Then, the mask pattern is corrected based on the first and second correction maps. By performing dimensional correction based on the arrangement of the mask pattern, it is possible to suppress global variation of the mask pattern.

The pattern creation unit 10 may be configured as a part of a central processing unit (CPU) of a normal computer system. The input unit 30, the map creation unit 32, the correction unit 34, the synthesis unit 36, the search unit 38, the graphic processing unit 40, the data conversion unit 42, and the output unit 44 may each be configured with dedicated hardware. The computer system CPU may be used to have a substantially equivalent function in software.
The external storage device 20 connected to the pattern creation unit 10 includes a design information file 12, a correction information file 14, a dangerous figure definition file 16, a drawing data file 18, and the like. The design information file 12 stores photomask design information including circuit specifications of the semiconductor device and layout data of circuit design mask patterns. The correction information file 14 is a mask pattern layout data obtained by performing OPC processing on a design mask pattern, an in-plane distribution of a dimensional correction amount defined from a global dimensional variation generated based on the arrangement of the mask pattern, and a global mask pattern. Stores correction procedure specifications and the like that define the procedure for correction of mechanical dimensions. The dangerous figure definition file 16 stores the definition of the dangerous figure defined based on the minimum step length of the step generated in the mask pattern by the OPC process. The drawing data file 18 stores drawing data of a mask pattern used for manufacturing a photomask.

  The external storage device 20 also stores program instructions for each process executed by the pattern creation unit 10. Program instructions are read into the pattern creating unit 10 as necessary, and arithmetic processing is executed. The external storage device 20 may be composed of a semiconductor memory device such as a semiconductor ROM or a semiconductor RAM, an auxiliary storage device such as a magnetic disk device, a magnetic drum device, or a magnetic tape device, or a main storage device of a CPU of a computer. It doesn't matter.

  The input unit 30 of the pattern creation unit 10 reads and acquires information such as the mask pattern, the dimensional correction amount distribution, and the correction procedure specification stored in the correction information file 14. For example, as shown in FIG. 2, the mask pattern 70 read from the correction information file 14 includes a first mask pattern 71, a second mask pattern 72, a third mask pattern 73, a fourth mask pattern 74, and A fifth mask pattern 75 is included. Although not shown in FIG. 2, the mask pattern 70 is corrected by OPC processing. OPC is performed by photolithography simulation using a computer. For example, as shown in FIG. 3, the correction steps 82a and 82b occur in the fifth mask pattern 75 that has been subjected to the OPC process. In addition, the dimensional correction amount is calculated based on the result of measuring in advance the exposure characteristics in-plane due to the optical characteristics such as the loading effect depending on the mask pattern density and local aberrations of the optical system of the drawing apparatus. Is done.

  Further, the input unit 30 acquires the minimum step length by the optical proximity effect correction and the minimum shot size of the drawing apparatus from the dangerous figure definition file 16. As shown in FIGS. 4 and 5, the dangerous figures 80a and 80b have a line segment length Dst of one line segment PLa that forms a right angle of the correction steps 82a and 82b generated by the OPC process, for example, less than the minimum step length of OPC, In addition, the line segment length Lst of the other line segment PLb is defined by a figure that is less than the minimum shot size of the drawing apparatus. The dangerous figure 80a is a protrusion-like step, and the dangerous figure 80b is a hollow-like step. Here, the step length generated in the OPC process is, for example, in the range of several nm to several hundred nm. Further, the minimum shot size of the EB drawing apparatus is, for example, about 70 to 100 nm. In the embodiment, the minimum step length of OPC is 4 nm, and the minimum shot size of the drawing apparatus is 100 nm. Note that the step length of the global dimensional variation correction is, for example, about 1 nm.

  Based on the acquired dimensional correction amount distribution, the map creation unit 32 creates a correction map by setting correction values for each of a plurality of small regions obtained by dividing the arrangement surface of the mask pattern 70 in a grid pattern. For example, in the first correction map 60, as shown in FIG. 6, a plurality of first small regions 62a to 62i in which correction values are set are arranged in a grid pattern on the first boundary line BLa. The In the second correction map 64, as shown in FIG. 7, the second small regions 66a to 66i are arranged in a lattice pattern on the second boundary line BLb. In the embodiment, each of the first and second small regions 62a to 62i and 66a to 66i has, for example, a lattice shape with one side of about 1 mm. However, the first and second small regions 62a to 62i and 66a to 66i may be regions having dimensions larger than the maximum dimension of a pattern that requires high accuracy such as a gate pattern of a MOS transistor.

  The patterns arranged in the first and second small areas 62a to 62i and 66a to 66i are positive and negative correction values set in the first and second small areas 62a to 62i and 66a to 66i, respectively. It is expanded or reduced by the amount. For example, each line segment of the pattern edge included in the first small region 62a is corrected so as to reduce the pattern by 4 nm. Each line segment of the pattern edge included in the second small region 66i is corrected so as to reduce the pattern by 1 nm. Note that correction processing is not performed in the first small region 62i and the second small region 66h whose correction value is 0. Further, as shown in FIG. 8, the first and second correction maps 60 and 64 are configured such that each of the second small areas 66a to 66i has a half-grid portion with respect to each of the first small areas 62a to 62i. It is arranged just shifted. The first mask pattern 71 is disposed so as to be completely included in the first small region 62a. The second mask pattern 72 intersects with the first boundary line BLa, but is completely included in the second small region 66c. The third to fifth mask patterns 73 to 75 are arranged so as to cross both the boundary lines BLa and BLb.

  The correction unit 34 corrects the mask pattern 70 based on the correction procedure specification. First, using the first correction map 60, a pattern that does not intersect with the first boundary line BLa in the mask pattern 70 is corrected. For example, the first mask pattern 71 shown in FIG. 8 is corrected by the correction value set in the first small area 62a. Next, the correction unit 34 corrects a pattern that intersects the first boundary line BLa in the mask pattern 70 but does not intersect the second boundary line BLb by using the second correction map 64. For example, the second mask pattern 72 is corrected by the correction value set in the second small area 66c.

  Subsequently, as illustrated in FIGS. 9 to 11, the correction unit 34 is defined to include the first boundary line BLa at the first extended boundary line BEa provided on both sides of the first boundary line BLa. The first extended area 68 is added to the first correction map 60. Except for the first and second mask patterns 71 and 72 and the mask pattern overlapping with three or more first small regions, for example, at least one end in the first extended region 68 is a first extended. The third mask patterns 73, 73 a, and 73 b arranged on the inner side from the boundary line BEa are corrected using the first correction map 60. The third mask pattern 73 is corrected with a correction value that is not large, for example, in one of the first small regions 62d and 62g. Further, the third mask patterns 73a and 73b are corrected by the correction values of the first small regions 62k and 62j that protrude from the first extended boundary line BEa in the first small regions 62j and 62k. .

  Similarly, as illustrated in FIGS. 12 and 13, the correction unit 34 is defined to include the second boundary line BLb with the second extended boundary line BEb provided on both sides of the second boundary line BLb. The second extended area 69 is added to the second correction map 64. Except for the first to third mask patterns 71 to 73, 73a, 73b and the mask pattern overlapping with three or more second small regions, for example, at least one end is in the second extended region 69. The fourth mask patterns 74 and 74a arranged on the inner side from the second extended boundary line BEb are corrected. The fourth mask pattern 74 is corrected with a correction value that is not large in any one of the second small regions 66f and 66i. The fourth mask pattern 74a is corrected with the correction value of the second small region 66k that protrudes from the second extended boundary line BEb in the second small regions 66j and 66k.

  Further, the correction unit 34 corrects the mask pattern left uncorrected by performing a division process using the first correction map 60. For example, as shown in FIG. 14, the fifth mask pattern 75 is left uncorrected. As shown in FIG. 15, the first small regions 62e and 62f are separated from the first boundary line BLa intersecting with the fifth mask pattern 75. The fifth mask pattern 75 is divided into divided patterns 76a and 77a. As shown in FIG. 16, correction is performed with the correction values of the first small regions 62e and 62f for each of the divided patterns 76b and 77b in which the divided portions are expanded by the width Δp so that no gap is generated after the correction processing. To do.

  The synthesizer 36 combines the patterns corrected by dividing the fifth mask pattern 75. For example, as shown in FIG. 17, a correction pattern 175 is created by combining the correction division patterns 76c and 77c.

  The search unit 38 searches the dangerous pattern 80a, 80b for the correction pattern 175 obtained by correcting the fifth mask pattern 75 based on the definition of the dangerous graphic shown in FIGS. For example, as illustrated in FIGS. 18 to 21, a dangerous graphic 81 that is located in a vicinity region within the minimum shot size from the first boundary line BLa is extracted from the dangerous graphic 80 a. A minute pattern such as a minute protrusion 78a, a minute recess 78b, and minute steps 79a and 79b is generated in one line segment of the first boundary line BLa and the danger graphic 81. A shift corresponding to the difference between the correction values of the correction division patterns 76c and 77c of the correction pattern 175 occurs along the first boundary line BLa in the micro protrusions 78a, the micro indentations 78b, and the micro steps 79a and 79b. Although explanation is omitted, it goes without saying that the same applies to the dangerous figure 80b.

  The graphic processing unit 40 performs graphic processing to remove the minute pattern. First, the graphic processing unit 40 performs resizing processing on the correction pattern 175. The “resizing process” is a graphic process for reducing or expanding each of the patterns divided by the boundary line with a predetermined resizing correction value. As the resizing correction value, for example, a value of 1/2 or more of the distance from the first boundary line BLa to the ends of the minute protrusions 78a and the minute recesses 78b facing the first boundary line BLa is used. For example, the correction pattern 175 is temporarily reduced by the resizing correction value with respect to the minute protrusion 78a shown in FIG. By the reduction process, the minute protrusion 78a disappears. Thereafter, when the resizing correction value is expanded, a correction pattern in which the minute protrusion 78a is deleted from the correction pattern 175 is created. In the case of the minute recess 78b shown in FIG. 19, in contrast to the processing of the minute protrusion 78a described above, if the expansion process is first performed to reduce the size, the minute recess 78b is deleted from the correction pattern 175.

  The minute steps 79a and 79b as shown in FIGS. 20 and 21 cannot be removed by resizing. As a result, a minute figure is generated and drawing accuracy is deteriorated. Moreover, drawing data increases and drawing time increases. For example, in photomask drawing using an EB drawing apparatus or the like, a pattern is drawn for each shot area obtained by dividing the mask pattern data into a rectangular shape or a trapezoidal shape. In the shot division process, the image is divided based on the right angle in the pattern. For example, the correction pattern 175 having the minute step 79a shown in FIG. 20 is divided into shot areas 176a and 176b and a minute figure 178a as shown in FIG. Further, the correction pattern 175 having the minute step 79b shown in FIG. 21 is divided into shot areas 176a and 176b and a minute figure 178b as shown in FIG. Since the minute figures 178a and 178b include dimensions smaller than the minimum shot size, the drawing accuracy deteriorates. Further, the shot division is increased by the minute figures 178a and 178b, leading to an increase in drawing data and an increase in drawing time.

  In order to suppress the generation of minute figures, the graphic processing unit 40 performs a step removal process on the correction pattern 175. In the step removal process, as shown in FIG. 24, the fine step 79a generated outside the right-angle pattern is deleted to create a correction pattern 175a. Further, as shown in FIG. 25, the minute step 79b generated inside the right-angle pattern is embedded to create a correction pattern 175a. As shown in FIG. 26, the correction pattern 175a from which the minute steps 79a and 79b have been removed is divided into shot areas 176a and 176b having no minute figures. Further, as shown in FIG. 27, the drawing pattern 170 obtained by correcting the mask pattern 70 of FIG. 2 is corrected patterns 171, 172, and 173 that have been subjected to global dimensional variation correction and graphic processing by the correction unit 34 and the graphic processing unit 40. 174, 175a. The graphic processing unit 40 further divides the correction patterns 171, 172, 173, and 174 into shots.

  The data conversion unit 42 converts the drawing pattern 170 that has been divided into shots into drawing data for a drawing apparatus. The output unit 44 stores the created drawing data in the drawing data file 18 of the external storage device 20. Further, the output unit 44 temporarily stores data in the middle of calculation or processing in the external storage device 20 in the logical operation or graphic processing in the pattern creating unit 10.

  The internal memory 46 stores the layout acquired by the input unit 30, the first and second correction maps created by the map creation unit 32, the pattern corrected by the correction unit 34, the pattern synthesized by the synthesis unit 36, and the search The dangerous graphic searched by the unit 38, the pattern processed by the graphic processing unit 40, the drawing data created by the data converting unit 42, and the like are stored. Further, the internal memory 46 temporarily stores data being calculated or being processed in the logical operation or graphic processing in the pattern creating unit 10.

  The drawing system 50 includes a drawing control unit, a drawing device, and the like that are not shown. The drawing control unit acquires drawing data of the mask pattern from the drawing data file 18. The drawing apparatus draws a drawing pattern on the photomask substrate using the drawing data acquired by the drawing control unit, and manufactures a photomask.

  The input device 22 refers to a device such as a keyboard and a mouse. When an input operation is performed from the input device 22, the corresponding key information is transmitted to the pattern creation unit 10. The output device 24 indicates a screen such as a monitor, and a liquid crystal display (LCD), a light emitting diode (LED) panel, an electroluminescence (EL) panel, or the like can be used. The output device 24 displays a mask pattern processed by the pattern creation unit 10, a correction pattern obtained, and the like.

  As described above, in the mask pattern generation system according to the embodiment of the present invention, as shown in FIG. 8, the first correction map 60 divided by the first small regions 62a to 62i, and the first The global dimensional variation is corrected using the second correction map 64 divided by the second small areas 66a to 66i whose positions are shifted from the small areas 62a to 62i. Therefore, it is possible to reduce pattern division that occurs in correction of global dimensional variation. Further, as shown in FIGS. 18 to 21, the fine pattern generated in the dangerous graphic defined in the correction pattern 175 is removed by graphic processing. As a result, generation of minute figures due to shot division can be suppressed. Therefore, in drawing a mask pattern on the photomask substrate, an increase in drawing time can be suppressed and drawing accuracy can be improved.

  For example, a mask pattern of a semiconductor device such as a 130 nm node generation logic circuit is corrected. In the current global dimensional variation correction using only the first correction map 60, division processing is performed on about 3% of patterns. In the global dimensional variation correction according to the embodiment of the present invention using the first and second correction maps 60 and 64, the ratio of the pattern to be divided is reduced to about 3 × 10 −9. In the drawing pattern subjected to the global dimension variation correction and the graphic process, the ratio of the number of shots to the mask pattern without the correction process is about 1.003, and no obvious deterioration is observed. Furthermore, the division process by the global dimensional variation correction does not occur in a pattern that requires high-precision drawing such as a gate pattern of a MOS transistor provided in the logic circuit.

  Next, a pattern creation method according to the embodiment of the present invention will be described with reference to the flowchart shown in FIG. In the correction information file 14 of the external storage device 20 shown in FIG. 1, the OPC-processed mask pattern layout data, the dimensional correction amount distribution for correcting the global dimensional variation generated based on the arrangement of the mask pattern, and Stores correction procedure specifications and the like that define global dimensional variation correction procedures. Further, the dangerous figure is defined in the dangerous figure definition file 16 based on the minimum step length of the step generated in the mask pattern by the OPC process.

  (A) In step S100, the input unit 30 of the pattern creation unit 10 shown in FIG. 1 acquires the layout, dimension correction amount distribution, and correction procedure specification of the mask pattern 70 shown in FIG. Further, the dangerous graphic information is acquired from the dangerous graphic definition file 16 by the input unit 30.

  (B) In step S102, the map creating unit 32 sets a correction value based on the dimensional correction amount distribution in each of the plurality of first small regions 62a to 62i obtained by dividing the arrangement surface of the mask pattern 70 in a grid pattern. The first correction map 60 shown in FIG. 6 is created.

  (C) In step S103, the correction unit 34 extracts the first mask pattern 71 that is arranged apart from the first boundary line BLa that partitions the first small regions 62a to 62i. The first mask pattern 71 is corrected using the correction value set in the first correction map 60.

  (D) In step S104, the map creating unit 32 divides the first subregions 62a to 62i into the same lattice shape and shifts the positions of the second subregions with respect to the first subregions 62a to 62i. A correction value is set for each of the small regions 66a to 66i based on the dimensional correction amount distribution, and the second correction map 64 shown in FIG. 7 is created.

  (E) In step S105, the correction unit 34 extracts the second mask pattern 72 that is arranged apart from the second boundary line BLb that partitions the second small regions 66a to 66i. The second mask pattern 72 is corrected using the correction value set in the second correction map 64.

  (F) In step S106, the correction unit 34 provides the first extended boundary line BEa on both sides of the first boundary line BLa. A first extended area 68 defined to include the first boundary line BLa at the first extended boundary line BEa is added to the first correction map 60.

  (G) In step S107, the correction unit 34 removes the first and second mask patterns 71 and 72 and the mask patterns overlapping with the three or more first small areas, and the first extended area. A third mask pattern 73, at least one end of which is arranged in 68 at a distance from the first extended boundary line BEa, is corrected using the first correction map 60.

  (H) In step S108, the correction unit 34 provides the second extended boundary line BEb on both sides of the second boundary line BLb. A second extended area 69 defined to include the second boundary line BLb at the second extended boundary line BEb is added to the second correction map 64.

  (I) In step S109, the correction unit 34 removes the first to third mask patterns 71, 72, and 73 and the mask patterns overlapping with three or more second small regions, A fourth mask pattern 74 having at least one end disposed in the extended region 68 at a distance from the first extended boundary line BEa is corrected using the second correction map 64.

  (N) In step S110, the correction unit 34 uses the first boundary line BLa of the first correction map 60 for the fifth mask pattern 75 excluding the first to fourth mask patterns 71 to 74. Division processing is performed. In step S111, the correction unit 34 corrects each of the division patterns 76b and 77b shown in FIG. 16 divided by the first boundary line BLa based on the first correction map 60. In step S112, the combining unit 36 combines the divided patterns 76b and 77b and combines the correction pattern 175 shown in FIG.

  (L) In step S113, the search unit 38 searches the correction pattern 175 for the dangerous figures 80a and 80b based on the dangerous figure information shown in FIGS. A dangerous graphic 81 shown in FIGS. 18 to 21 is extracted from the dangerous graphic so as to be located in the vicinity region within the minimum shot size from the first boundary line BLa.

  (E) In step S114, the graphic processing unit 40 removes the minute protrusions 78a and the minute depressions 78b of the dangerous graphic 81 by resizing. Subsequently, the graphic processing unit 40 removes the minute steps 79a and 79b of the dangerous graphic 81 by the step removal process. In this way, a correction pattern 175a in which the fifth mask pattern 75 is corrected is created. In addition, the graphic processing unit 40 divides each of the correction patterns 171 to 174 and 175a shown in FIG.

  (W) In step S115, the data conversion unit 42 converts the shot-divided drawing pattern 170 into drawing data for the drawing apparatus. In step S 116, the converted drawing data is stored in the drawing data file 18 of the external storage device 20 by the output unit 44.

  As described above, according to the mask pattern creation method according to the embodiment of the present invention, it is possible to reduce pattern division that occurs in correction of global dimensional variation. In addition, generation of minute figures due to shot division can be suppressed, and in drawing a mask pattern, an increase in drawing time can be suppressed and drawing accuracy can be improved.

  Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. It goes without saying that the present invention includes various embodiments not described herein. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a figure which shows an example of the mask pattern production system which concerns on embodiment of this invention. It is a figure which shows an example of the mask pattern used for description of embodiment of this invention. It is a figure which shows an example of the OPC correction mask pattern used for description of embodiment of this invention. It is a figure which shows an example of the danger figure used for description of embodiment of this invention. It is a figure which shows the other example of the danger figure used for description of embodiment of this invention. It is a figure which shows an example of the 1st correction map which concerns on embodiment of this invention. It is a figure which shows an example of the 2nd correction map which concerns on embodiment of this invention. It is a figure which shows an example of arrangement | positioning relationship of the mask pattern which concerns on embodiment of this invention, and a 1st and 2nd correction map. It is a figure which shows an example of the 3rd mask pattern which concerns on embodiment of this invention. It is a figure which shows the other example of the 3rd mask pattern which concerns on embodiment of this invention. It is a figure which shows the further another example of the 3rd mask pattern which concerns on embodiment of this invention. It is a figure which shows an example of the 4th mask pattern which concerns on embodiment of this invention. It is a figure which shows the other example of the 4th mask pattern which concerns on embodiment of this invention. It is a figure which shows an example of the 5th mask pattern which concerns on embodiment of this invention. It is FIG. (1) which shows an example of the division | segmentation process of the 5th mask pattern which concerns on embodiment of this invention. It is FIG. (2) which shows an example of the division | segmentation process of the 5th mask pattern which concerns on embodiment of this invention. It is FIG. (3) which shows an example of the division | segmentation process of the 5th mask pattern which concerns on embodiment of this invention. It is a figure which shows an example of the microprotrusion of the danger figure which concerns on embodiment of this invention. It is a figure which shows an example of the minute hollow of the danger figure which concerns on embodiment of this invention. It is a figure which shows an example of the micro level | step difference of the danger figure which concerns on embodiment of this invention. It is a figure which shows the other example of the micro level | step difference of the danger figure which concerns on embodiment of this invention. It is a figure which shows an example of the shot division | segmentation of the correction pattern which the micro level | step difference generate | occur | produced. It is a figure which shows the other example of shot division | segmentation of the correction pattern which the micro level | step difference generate | occur | produced. It is a figure which shows an example of the level | step difference removal process of the dangerous figure which concerns on embodiment of this invention. It is a figure which shows the other example of the level | step difference removal process of the dangerous figure which concerns on embodiment of this invention. It is a figure which shows an example of the shot division | segmentation of the correction pattern which concerns on embodiment of this invention. It is a figure which shows an example of the drawing pattern which concerns on embodiment of this invention. It is a flowchart which shows an example of the mask pattern production method which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pattern creation unit 12 Design information file 14 Correction information file 16 Danger figure definition file 18 Drawing data file 20 External storage device 22 Input device 24 Output device 30 Input part 32 Map creation part 34 Correction part 36 Composition part 38 Search part 40 Graphic processing Unit 42 data conversion unit 44 output unit 46 internal memory 50 drawing system 60 first correction map 62a to 62k first small area 64 second correction map 66a to 66k second small area 68 first extended area 69 first Two extended regions 70 ... mask pattern 71 first mask pattern 72 second mask pattern 73, 73a, 73b third mask pattern 74, 74a fourth mask pattern 75 fifth mask pattern 76a, 76b, 77a, 77b Dividing pattern 76b ... Dividing pattern 76c, 77c Correction division pattern 78a Small protrusion 78b Small depression 79a, 79b Small step 82a, 82b Correction step 170 Drawing pattern 171-175, 175a Correction pattern 176a, 176b Shot area

Claims (5)

A map creation unit creates a first correction map in which a first dimensional correction amount is set based on the mask pattern arrangement in each of a plurality of first small areas obtained by dividing the mask pattern arrangement plane in a grid pattern And
The map creation unit sets a second dimensional correction amount based on the arrangement of the mask pattern in each of a plurality of second small regions whose boundary positions are shifted with respect to the plurality of first small regions. Create a second correction map,
A mask pattern generation method comprising: correcting the mask pattern based on the first and second correction maps by a correction unit.   The first and second dimensional correction amounts are given based on respective pattern densities of the first and second small regions of the mask pattern and characteristics of an apparatus for transferring the mask pattern to a photomask substrate. The mask pattern creating method according to claim 1. Among the mask patterns,
Correcting a first mask pattern arranged so as to be completely included in each of the plurality of first small regions based on the first correction map;
Correcting a second mask pattern arranged so as to be completely included in each of the plurality of second small regions except for the first mask pattern, based on the second correction map. The mask pattern creation method according to claim 1 or 2, wherein Among the mask patterns,
Providing a first extension region so as to contact the outside of the first small region;
Except for the first and second mask patterns and a mask pattern overlapping with three or more first small regions, a third mask having at least one end included in the first extended region Correcting the pattern based on the first correction map;
A second extended region is disposed so as to contact the outside of the second small region,
A fourth mask including at least one end in the second extended region except for the first to third mask patterns and a mask pattern overlapping with three or more second small regions. Correcting the pattern based on the second correction map;
Dividing the fifth mask pattern excluding the first to fourth mask patterns into divided patterns by the first correction map;
The mask pattern creation method according to claim 3, further comprising: correcting the division pattern based on the first correction map. Obtain a mask pattern that has been subjected to optical proximity correction based on the calculation of an optical image of an exposure apparatus that transfers the photomask pattern to a resist film on a semiconductor substrate,
A first correction map in which a first dimensional correction amount is set based on the arrangement of the mask pattern in each of a plurality of first small areas obtained by dividing the arrangement surface of the mask pattern in a grid pattern by the correction unit; A second correction map in which a second dimensional correction amount is set based on the arrangement of the mask pattern in each of a plurality of second small regions whose boundary positions are shifted with respect to the plurality of first small regions; Create a correction pattern by correcting the mask pattern based on
In the mask pattern, one of the two line segments forming a right angle is less than the minimum step length by the optical proximity effect correction, and the other line segment length of the two line segments is applied to the photomask substrate. Search for dangerous figures that are less than a threshold based on the minimum shot size for drawing the mask pattern,
A mask pattern creation method comprising: removing, by a graphic processing unit, a minute pattern equal to or less than the threshold value included in the correction pattern in the dangerous graphic.

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