JPH10240783A - Device and method for desining photomask pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fine machining precision by extracting a pattern cell which meets specific requirements from a photomask pattern, and substituting optimum pattern cells in a data base for the extracted pattern cells. SOLUTION: A photomask pattern data generation part 4 generates photomask pattern data on the photomask pattern. A pattern extraction part 7 extracts pattern cells which meet the specific requirements from the photomask pattern. A storage part 5 performs light-intensity simulation for pattern cells and previously stores optimum pattern cells optimized for fine machining according to the result obtained by calculating a distribution of light intensity of the pattern cells. A pattern conversion part 9 substitutes the optimum pattern cells in the data base for the pattern cells extracted by the pattern extraction part 7. Consequently, the fine machining precision is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photomask pattern designing apparatus and a photomask pattern designing method used for designing a photomask pattern.

[0002]

2. Description of the Related Art Conventionally, in the research and development or development prototype stage of a semiconductor process, computer simulation has been used as a technique for grasping the characteristics of a process and a product and simulating prediction and evaluation of device characteristics with respect to manufacturing conditions. Technology is being used, and that technology is currently being actively used. In particular, among many computer simulation technologies, the simulation technology used in the photolithography process in the core microfabrication technology of semiconductor manufacturing technology has been theoretically established and is an indispensable technology in research and development. is there.

[0003] The simulation technology of the exposure process in the photolithography process is particularly called a light intensity simulation technology, which is used when a photomask pattern is exposed and transferred to the surface of a semiconductor wafer using a projection exposure apparatus (stepper). The light intensity distribution of the projection optical image is obtained by calculation. In practice, the light intensity simulation is executed by a computer using software called a light intensity simulator.

[0004] As a physical theory underlying the light intensity simulation technique described above, H. H. Hopkins
The imaging optics theory established by them is known. For more information on this imaging optics theory, see Born, Wolf
Written by "Principles of Optics II and III", 1975, or Hop
Kins; Opt. Soc. Am. Vol. 47,
No. 6 ('57) p508. further,
Lin or Ye as the computer calculation model
See also the model by ung.

In addition, the above-described light intensity simulation technique has an advantage that the exposure distribution on the surface of the semiconductor wafer can be estimated by calculation without actually performing photolithography on the semiconductor wafer. Therefore, it is frequently used in research and development of photolithography processes and device prototypes. Particularly, in recent years, the fact that firstly the processing accuracy required for the fine processing technology is about to reach the limit of processing by light, and secondly, considering the technical and cost aspects, experiments have been actually repeated. In view of the background that device development is difficult to perform, light intensity simulation technology has become increasingly important. This is because light intensity simulation technology
The advantage is that the result (light intensity distribution) can be obtained quickly and at low cost by using a computer.

In a semiconductor wafer pattern design process, a technique called design simulation has been conventionally used. Although this design simulation is a technique different from the light intensity simulation described above, it is a technique for obtaining desired electronic characteristics and circuit characteristics in logic design, circuit design, and the like, and is currently indispensable in mass production processes. is there. The above-described pattern design process is roughly divided into four processes, that is, a functional design process, a logic design process, a circuit design process, and a mask pattern design process, taking a general full custom design LSI process as an example.

FIG. 2 is a flowchart for explaining the conventional pattern design process described above, and is a flowchart for explaining a general LSI pattern design process as an example. In FIG. 2, after a functional design having required performance is performed in step SA1, a logical design is performed in step SA2, and a logical circuit satisfying the functional design is designed.

In step SA3, in order to realize the characteristics required by the embedded circuit designed in step SA2,
A specific circuit including components such as a transistor and a wiring is designed. At Step SA4, Step SA
The mask pattern is designed to determine the shape and arrangement of the individual transistors in the circuit designed in 3 based on the design rules.

Here, the above-mentioned design rule is an LSI
The geometric design rules defined based on the microfabrication accuracy of the manufacturing process and the electronic characteristics of the device, for example,
It refers to the minimum line width of each line, the minimum distance between the line and a line adjacent thereto, the diameter of a contact hole, and the tolerance of alignment between layers. That is, the design rule is a rule for optimizing two-dimensional wiring.

More specifically, in step SA4, a CAD (Computer Aided Design) tool for design is used to
By appropriately combining a plurality of symbol diagrams in which elements and wirings are represented by symbols, a photomask pattern satisfying the above-described design rule is designed.

In step SA5, a design rule check (DRC) for verifying whether all the photomask patterns designed in step SA4 satisfy the design rule is performed. Specifically, in step SA5, a design tool check for a photomask pattern is performed by a verification tool called a DRC system, pattern correction is performed for a problematic part, and then photomask pattern data is generated. .

At step SA6, the photomask pattern data generated at step SA5 is output. Then, in step SA7, after a photomask is actually created based on the photomask pattern data, a photolithography process is performed using the photomask.

[0013]

By the way, in the above-described photomask pattern designing method, a series of designing operations described with reference to FIG. 2 are mainly performed mainly to satisfy the logical characteristics of the circuit. Therefore, a photolithography process (step S
The microfabrication in A7) is not considered, and the device characteristics actually obtained cannot be optimized. In the above-described photomask pattern designing method, the photomask created in step SA7 (hereinafter, referred to as a normal photomask) is replaced with an optical proximity effect correction technology as an extreme technology of microfabrication in a photolithography process, or an ultra-fine technology. It cannot be directly applied to resolution technology. That is, in order to apply the ordinary photomask to the optical proximity correction technology or the like, a photolithography process, at least a photomask pattern design in consideration of an exposure process is necessary, and specifically, the light intensity simulation described above is used. Then, it is necessary to optimize the photomask pattern based on the exposure condition in the optical proximity correction technology or the like. Therefore, in order to apply the photomask pattern (data) generated in step SA6 to the optical proximity correction technique, the photomask pattern must be reorganized based on a special processing rule (hereinafter, referred to as a pattern design rule). I just need. The pattern design rule is a rule dedicated to super-resolution technology or the like, and is completely different from the design rule described above, and is determined by exposure conditions and process conditions in a photolithography process.

However, as is well known, the photomask pattern of an actual LSI circuit is very complicated and enormous, and is composed of hundreds of thousands to millions of closed figures. Performing the above-described light intensity simulation to optimize the fine processing accuracy for the entire photomask pattern having such an enormous data amount is not practical in consideration of the computer processing speed and the time required for the simulation calculation. Impossible. It is also conceivable to manually extract a part to be optimized (hereinafter referred to as a pattern cell) from all the photomask patterns and then perform light intensity simulation on the pattern cell. It is not realistic considering a great deal of labor and human error. In summary, the photomask pattern design method described above cannot easily obtain a photomask pattern that satisfies the recent fine processing accuracy, and furthermore, the data amount of the photomask pattern is enormous, so that light intensity simulation is performed. It is practically difficult to optimize the pattern.

The present invention has been made in view of such a background, and provides a photomask pattern designing apparatus and a photomask pattern designing method capable of easily obtaining a photomask pattern with improved fine processing accuracy. With the goal.

[0016]

According to a first aspect of the present invention, there is provided a photomask pattern designing apparatus, comprising: a photomask pattern data generating unit configured to generate photomask pattern data of a photomask pattern; Pattern cell extracting means for extracting a pattern cell satisfying a predetermined condition in the photomask pattern, and a light intensity simulation performed on a plurality of the pattern cells to calculate a light intensity distribution in the pattern cells. Storage means for storing in advance a plurality of optimum pattern cells optimized for microfabrication as a database, and replacement for replacing the pattern cells extracted by the pattern cell extraction means with the optimum pattern cells in the database Means. To. According to a second aspect of the present invention, in the photomask pattern designing apparatus according to the first aspect, a search unit that searches a database for the optimum pattern cell corresponding to the pattern cell extracted by the pattern cell extraction unit. Wherein the replacement unit replaces the pattern cell extracted by the pattern cell extraction unit with the optimal pattern cell searched by the search unit. According to a third aspect of the present invention, in the photomask pattern designing apparatus according to the first aspect, when the optimum pattern cell corresponding to the pattern cell extracted by the pattern cell extracting means does not exist in the database, Optimal pattern cell generation for newly generating an optimal pattern cell optimized for fine processing based on a result obtained by performing a light intensity simulation on the pattern cell and calculating a light intensity distribution in the pattern cell by calculation. Means for replacing the pattern cells extracted by the pattern cell extracting means with the optimum pattern cells of the database, and replacing the pattern cells extracted by the pattern cell extracting means with the new optimum pattern cells generated by the optimum pattern cell generating means. It is characterized by being replaced with According to a fourth aspect of the present invention, in the photomask pattern designing apparatus according to any one of the first to third aspects, an output unit for outputting data of the photomask pattern in which the optimal pattern cell is incorporated is provided. It is characterized by doing. According to a fifth aspect of the present invention, the photomask pattern design apparatus satisfies a first step of generating photomask pattern data of a photomask pattern and a predetermined condition in the photomask pattern based on the photomask pattern data. A second step of extracting pattern cells, and a light intensity simulation is performed on a plurality of the pattern cells, and a distribution of light intensity in the pattern cells is calculated, and the light intensity distribution is optimized for fine processing based on the results obtained. A third step of storing the plurality of optimum pattern cells as a database in a storage unit in advance, and a fourth step of replacing the pattern cells extracted in the second step with the optimum pattern cells of the database. It is characterized by the following. According to a sixth aspect of the present invention, in the photomask pattern designing method according to the fifth aspect, a fifth step of outputting data of the photomask pattern in which the optimal pattern cell is incorporated is provided. And According to a seventh aspect of the present invention, there is provided a photomask pattern designing method, wherein a first step of generating photomask pattern data of a photomask pattern and a predetermined condition in the photomask pattern are performed based on the photomask pattern data. Second to extract pattern cells that satisfy
And, based on the results obtained by performing light intensity simulation on the plurality of pattern cells and calculating the light intensity distribution in the pattern cells by calculation, forming a plurality of optimal pattern cells optimized for fine processing. A third step of storing in the storage means as a database in advance, a fourth step of searching the database for the optimum pattern cell corresponding to the pattern cell extracted in the second step, and a second step of And a fifth step of replacing the extracted pattern cells with the optimum pattern cells searched in the fourth step. Further, in the photomask pattern designing method according to the present invention, a first step of generating photomask pattern data of a photomask pattern, and a predetermined condition in the photomask pattern based on the photomask pattern data. A second process of extracting pattern cells to be filled, and a light intensity simulation performed on a plurality of the pattern cells, and a light intensity distribution in the pattern cells is calculated. A third process of storing in advance the plurality of optimum pattern cells thus obtained as a database in a storage unit;
A fourth step of replacing the pattern cell extracted in the second step with an optimal pattern cell in the database, and the optimal pattern cell corresponding to the pattern cell extracted in the second step is stored in the database. If it does not exist, a light intensity simulation is performed on the pattern cell, and a light intensity distribution in the pattern cell is calculated, and an optimum pattern cell optimized for fine processing is newly generated based on a result obtained by calculation. And a sixth step of replacing the pattern cell extracted in the second step with the optimal pattern cell newly generated in the fifth step. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a photomask pattern designing apparatus according to one embodiment of the present invention. In this figure, reference numeral 1 denotes a mask pattern data input unit, which is used for inputting photomask pattern data generated using the CAD tool described above. That is, the photomask pattern data is as shown in FIG.
Is normal photomask pattern data output in step SA6 shown in FIG.

Reference numeral 2 denotes a pattern feature input unit, which should be optimized in a normal photomask pattern for the purpose of improving the precision of fine processing when a photomask pattern is created by using the above-described optical proximity correction technique or the like. It is used for inputting a pattern design rule which is a condition for extracting a photomask pattern portion. Further, the pattern feature input unit 2 outputs the input pattern design rule as pattern design rule data.

The above-mentioned pattern design rule is determined in consideration of the exposure conditions and the like in a photolithography process of a semiconductor wafer performed as a subsequent process. The reason is as follows. As described above, in the photolithography process of the recent VLSI manufacturing process, it is necessary to improve the resolution and the depth of focus by using an optical proximity effect correction technology, a phase shift mask technology, a modified illumination technology, or the like.

That is, the photomask pattern in the optical proximity effect correction technique or the like not only serves as an original for a simple LSI pattern, but also as an original for realizing desired fine processing accuracy when forming a photomask pattern on a semiconductor wafer. Because it also fulfills the role of
Therefore, the photomask pattern applied to the optical proximity effect correction technology or the like must be optimized so that the fine processing accuracy is considered for the pattern cell to be optimized for the normal photomask pattern. It is.

Here, the pattern cell to be optimized is
This refers to a portion where the desired fine processing accuracy cannot be maintained in the optical proximity effect correction technique or the like. That is, a pattern design rule is applied to a normal pattern portion to be optimized. The specific limit value of the pattern design rule differs depending on which of a plurality of process technologies is used in the photolithography process of the semiconductor wafer. Specifically, the pattern cells to be optimized to which the above-mentioned pattern design rule is applied are, for example, a wiring portion having a dense pattern, a portion where contact holes are arranged in parallel, a portion where memory cell patterns are arranged, and the like. .

For example, when the Levenson type phase shift mask technology is used as the process technology, the pattern design rule is determined in consideration of the light shielding layer pattern and the phase shift layer. Specifically, the pattern design rule is a rule that mainly determines whether the dimension width and the pattern interval are predetermined values. However, since the photomask pattern to be applied is a two-dimensional plane, the pattern design rule is naturally determined in consideration of both the X direction and the Y direction in two dimensions. That is, when the pattern design rule is applied to a normal photomask pattern, a pattern cell to be optimized having the dimension width and the pattern interval equal to or smaller than predetermined values is extracted.

When a technology other than the above-mentioned Reverson type phase shift mask technology is used as a process technology, conditions specific to the technology, such as a dimension width such as a phase shift mask, are used as a pattern design rule.

When the above-described pattern design rule is applied, a conventional design rule check method for checking a logic circuit is used. That is, in this case, in the conventional design rule check method, basic design rules such as pattern dimension width, pattern interval, overlap width, minimum width, minimum interval, and minimum area are represented by numerical values for pattern design rules. You can specify it. Therefore, in the photomask pattern designing apparatus according to the present embodiment, a conventional logic circuit verification tool is applied as it is as a design rule check system.

Reference numeral 3 denotes a display unit for displaying various information necessary for designing a photomask pattern.
Keyboard, mouse, etc. are connected. The operator performs various operations by operating a keyboard or the like while checking the display screen of the display unit 3. In the mask pattern data creation unit 4, reference numeral 5 denotes a storage unit which stores the above-described photomask pattern data and pattern design rule data.

Reference numeral 6 denotes a design rule check unit for checking whether or not the above-described ordinary photomask pattern conforms to the pattern design rule. Specifically, the design rule check unit 6 reads out the photomask pattern data and the pattern design rule data stored in the storage unit 5, and applies the pattern design rule to the photomask pattern obtained from both data.

Reference numeral 7 denotes a pattern extraction unit which extracts a portion of the photomask pattern which does not conform to the pattern design rule, that is, a pattern cell to be optimized (hereinafter referred to as a pre-optimization pattern cell) in the design rule check unit 6. I do. Reference numeral 8 denotes an optimized pattern cell database unit, in which data of a pattern cell before optimization and data of a pattern cell in which the pattern cell before optimization has been optimized (hereinafter, referred to as a pattern cell after optimization) are 1 A plurality of set data is stored as a database in a storage medium (not shown).

That is, the data of the pattern cell after optimization is data obtained by analyzing the pattern cell before optimization based on the light intensity simulation for the purpose of improving the fine processing accuracy based on the simulation conditions in advance. is there. Here, as the light intensity simulation conditions, exposure parameters such as an exposure wavelength, a numerical aperture, a coherence degree, and a defocus amount are prepared. When the light intensity simulation is actually performed, the parameters are used in an actual semiconductor wafer exposure process. The specific numerical value obtained is substituted for the exposure parameter.

More specifically, since the above-mentioned exposure parameters are determined as one, the dimension width and pattern interval of the pattern are allotted to several values in order to obtain the optimum condition of the fine processing accuracy. The light intensity simulation is performed a plurality of times with the values. Next, a plurality of results of the optical simulation are compared with each other, and the best result is obtained as a simulation condition.

The optimized pattern cell database section 8 stores, in addition to the data of the pattern cells before optimization and the pattern cell data after optimization, that is, data relating to the two-dimensional figure, a dimension width, a pattern interval, and a figure. Information on pattern design rules such as types is stored in a database. The database of the optimized pattern cell database unit 8 can be searched by a normal database search method.

Reference numeral 9 denotes a pattern conversion unit which converts the data of the pre-optimized pattern cells extracted by the pattern extracting unit 7 into the data of the optimized pattern cells of the optimized pattern cell database unit 8 in the photomask pattern. Replace. Reference numeral 10 denotes a pattern data output unit which outputs data obtained by incorporating the optimized pattern cell data into the photomask pattern data (hereinafter, referred to as optimized photomask pattern data). 11 is a disk drive, a tape drive, a CRT (cathoderay tub)
e) an output unit comprising a printer or the like, which converts the optimized photomask pattern data into digital information,
Or output as hard copy.

Next, the operation of the photomask pattern designing apparatus according to the above-described embodiment will be described. In FIG. 1, when photomask pattern data is input from the mask pattern data input unit 1 and pattern design rule data is input from the pattern feature input unit 2, the photomask pattern data and the pattern design rule data are stored in the storage unit 5. Respectively.

When the operator operates a keyboard (not shown) of the display unit 3 to issue a pattern data creation command, the design rule check unit 6
The photomask pattern data and the pattern design rule data are read from the storage unit 5. Next, the design rule check unit 6 checks whether or not the photomask pattern obtained from the photomask pattern data conforms to the pattern design rule. That is, the design rule check unit 6 checks whether there is a pre-optimization pattern cell in the photomask pattern.

Next, the pattern extraction unit 7 extracts the pre-optimization pattern cell checked by the design rule check unit 6 from the photomask pattern, and then extracts it from the optimization pattern cell database unit 8 and the pattern conversion. Output to the unit 9 respectively.

The optimization pattern cell database unit 8
The design rules such as the pattern shape, dimensions, and pattern intervals of the pre-optimization pattern cells are checked, and a search is made as to whether a pre-optimization pattern cell having the same design rule as the above-mentioned design rule exists in the database.
If the pre-optimization pattern cell exists in the database, the optimization pattern cell database unit 8
Extracts a pattern cell after optimization that forms a pair with the pattern cell before optimization from the database, and outputs this to the pattern conversion unit 9.

Thus, the pattern conversion unit 9 replaces the pre-optimization pattern cell input from the pattern extraction unit 7 with the post-optimization pattern cell input from the optimization pattern cell database unit 8, and then performs optimization. The data of the subsequent pattern cell is output to the pattern data output unit 10.

Then, the pattern data output unit 10 outputs optimized photomask pattern data in which the above-mentioned optimized pattern cell data is incorporated into the photomask pattern data. The output unit 11 outputs the optimized photomask pattern data as digital information or a hard copy.

On the other hand, in the optimized pattern cell database unit 8, if the pre-optimized pattern cell input from the pattern extracting unit 7 does not exist in the database,
A simulator (not shown) is activated for the extracted pre-optimization pattern cell to perform light intensity simulation analysis. As a result, an optimized pattern cell is newly generated, and the optimized pattern cell is used in the optimized pattern cell database unit 8.

However, in the pattern design of circuit elements such as memories and gate array circuits in which most of the pre-optimization pattern cells are shared, most of the pre-optimization pattern cells are stored in a database. Therefore, it is rare that a simulator (not shown) is activated to newly generate an optimized pattern cell that does not exist in the database.

The above-described design rule check section 6, pattern extraction section 7, and optimized pattern cell database section 8 actually perform a series of operations by software processing. It is executed by an execution file of software stored in the storage device and the external storage device.

As described above, according to the photomask pattern designing apparatus and the photomask pattern designing method according to the embodiment of the present invention, only the pre-optimized pattern cells to be optimized for the normal photomask pattern are extracted. After that, since only the pre-optimization pattern cell is optimized, a photomask pattern with improved fine processing accuracy can be easily created.

Further, according to the photomask pattern designing apparatus and the photomask pattern designing method according to the above-described embodiment, a method of extracting a pre-optimized pattern cell to be optimized from the photomask pattern is used. In addition, even when optimizing a photomask pattern having an enormous data amount, the optimization can be performed automatically in a short time.

[0043]

As described above, according to the present invention,
An optimal pattern cell is prepared in advance as a database, and the pattern cell extracted by the pattern cell extracting means is replaced with the optimal pattern cell in the database, thereby performing optimization for achieving the finest processing accuracy. A photomask pattern with improved processing accuracy can be easily created, and even when optimizing a photomask pattern with a large amount of data, optimization can be performed automatically in a short time. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a photomask pattern designing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a conventional LSI pattern design process.

[Explanation of symbols]

 Reference Signs List 1 mask pattern data input unit 2 pattern feature input unit 3 display unit 4 mask pattern data creation unit 5 storage unit 6 design rule check unit 7 pattern extraction unit 8 optimization pattern cell database unit 9 pattern conversion unit 10 pattern data output unit 11 output Department

Claims (8)

[Claims] 1. A photomask pattern data generating means for generating photomask pattern data of a photomask pattern, and a pattern cell for extracting a pattern cell satisfying a predetermined condition in the photomask pattern based on the photomask pattern data. Extraction means, based on the results obtained by performing light intensity simulations on the plurality of pattern cells and calculating the light intensity distribution in the pattern cells by calculation, form a plurality of optimal pattern cells optimized for fine processing. A photomask pattern designing apparatus, comprising: a storage unit that stores in advance as a database; and a replacement unit that replaces the pattern cell extracted by the pattern cell extraction unit with the optimal pattern cell in the database. 2. The apparatus according to claim 1, further comprising: a search unit configured to search a database for the optimum pattern cell corresponding to the pattern cell extracted by the pattern cell extraction unit, wherein the replacement unit extracts the pattern cell extracted by the pattern cell extraction unit. The photomask pattern designing apparatus according to claim 1, wherein a pattern cell is replaced with the optimum pattern cell searched by the search unit. 3. If the optimum pattern cell corresponding to the pattern cell extracted by the pattern cell extracting means does not exist in the database, light intensity simulation is performed on the pattern cell and the light intensity distribution in the pattern cell is determined. Based on the results obtained by calculating each of the above, comprising an optimum pattern cell generating means for newly generating an optimum pattern cell optimized for fine processing, wherein the replacing means is extracted by the pattern cell extracting means 2. The photomask pattern design according to claim 1, wherein the pattern cell is replaced with the new optimal pattern cell generated by the optimal pattern cell generation unit, instead of the optimal pattern cell in the database. 3. apparatus. 4. The photomask pattern designing apparatus according to claim 1, further comprising an output unit configured to output data of the photomask pattern in which the optimum pattern cell is incorporated. 5. A first step of generating photomask pattern data of a photomask pattern, and a second step of extracting a pattern cell satisfying a predetermined condition in the photomask pattern based on the photomask pattern data. Based on the results obtained by performing light intensity simulations on the plurality of pattern cells and calculating the light intensity distribution in the pattern cells by calculation, storing a plurality of optimal pattern cells optimized for fine processing as a database. A third step of storing the pattern cells extracted in the second step with the optimum pattern cells of the database in advance. Method. 6. The photomask pattern designing method according to claim 5, further comprising a fifth step of outputting data of the photomask pattern in which the optimal pattern cell is incorporated. 7. A first step of generating photomask pattern data of a photomask pattern, and a second step of extracting a pattern cell satisfying a predetermined condition in the photomask pattern based on the photomask pattern data. Based on the results obtained by performing light intensity simulations on the plurality of pattern cells and calculating the light intensity distribution in the pattern cells by calculation, a plurality of optimal pattern cells optimized for fine processing as a database. A third step of storing in the storage means in advance; a fourth step of searching the database for the optimal pattern cell corresponding to the pattern cell extracted in the second step; and a fourth step of extracting in the second step The optimal pattern retrieved in the fourth step by using the pattern cell Photomask pattern design method characterized in that it comprises a fifth step of replacing Le, a. 8. A first step of generating photomask pattern data of a photomask pattern, and a second step of extracting a pattern cell satisfying a predetermined condition in the photomask pattern based on the photomask pattern data. Based on the results obtained by performing light intensity simulations on the plurality of pattern cells and calculating the light intensity distribution in the pattern cells by calculation, a plurality of optimal pattern cells optimized for fine processing as a database. A third step of storing in the storage means in advance, a fourth step of replacing the pattern cell extracted in the second step with an optimal pattern cell of the database, and a step of extracting the pattern cell extracted in the second step. The optimum pattern cell corresponding to the pattern cell does not exist in the database If the distribution of light intensity in the pattern cell performs light intensity simulation for the pattern cells based on each calculated result by calculation, the newly generates an optimized optimum pattern cell for microfabrication 5
And a sixth step of replacing the pattern cells extracted in the second step with the optimal pattern cells newly generated in the fifth step. Pattern design method.