JPH11111595A - Charged particle beam exposure method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an appropriate proximity exposure effect by obtaining pattern density in an area in a sub field, by reconsidering the pattern density according to the pattern density of a surrounding area and the distance between areas, and by generating an auxiliary exposure pattern when the density is lower than a predetermined exposure density. SOLUTION: In a process S14, a pattern density in each area in a sub field is obtained. In a process S15, the pattern density in each area is reconsidered according to the pattern density of a surrounding area and the distance between areas. In a process S16, a pattern existence region in the sub field with a high density is detected. When a substantial pattern density SRmn is higher than a reference value, the amount of exposure of the pattern belonging to the area is reduced in a process S17. On the other hand, when the substantial pattern density SRmn is lower that the reference value, an auxiliary exposure pattern is generated and added to exposure data in a process S18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam exposure method and a charged particle beam exposure apparatus, and more particularly to exposure data for exposing a pattern on a semiconductor wafer by a charged particle beam such as an electron beam. The present invention relates to a method and a charged particle beam exposure apparatus for performing the method.

[0002]

2. Description of the Related Art Exposure to charged particle beams such as electron beams
A submicron pattern can be exposed, and is used in a manufacturing process of an LSI having a high degree of integration. In particular, recently, not only is it used for the manufacture of masks, but also exposure is performed by directly irradiating a resist formed on a semiconductor wafer with a charged particle beam.

In an LSI design process, pattern data having a plurality of layer structures is created in order to form a desired integrated circuit. The resist on the semiconductor wafer or the resist on the mask substrate is exposed according to the pattern data. Exposure is performed by irradiating the resist film with a charged particle beam and causing a chemical reaction in the resist by the energy of the beam.

In this case, a point to be considered is a proximity exposure effect caused by forward scattering and back scattering of the charged particle beam when the resist is irradiated on the resist. The proximity exposure effect is a phenomenon in which when a charged particle beam is irradiated on a certain area, the energy of the beam spreads to an adjacent area due to scattering of the beam. For example, in a region where the exposure pattern density is high, the pattern after development expands due to the influence of the energy of the charged particle beam applied to the adjacent exposure pattern region. Alternatively, in a region where the exposure pattern density is low, there is no influence of energy from an adjacent region, and the pattern after development is reduced or thinned.

Therefore, in consideration of the proximity exposure effect,
It is necessary to correct the designed exposure data. The present applicant has disclosed a method of correcting such exposure data in a patent application filed on January 29, 1996 (Japanese Patent Application No.
3354 (JP-A-8-321462) has been proposed.

[0006] In summary, the method proposed in this patent application generates a plurality of mask areas in a subfield, and modifies the pattern density in the area according to the influence of the pattern density of the surrounding area. Then, a substantial pattern density is determined in consideration of the proximity exposure effect, the exposure amount (exposure intensity) of the pattern belonging to the area is corrected according to the substantial pattern density, and an auxiliary exposure pattern is generated.

[0007]

However, an area having a predetermined size is generated irrespective of the position of the pattern existing in the subfield, and the auxiliary exposure pattern is generated using the area as a pattern unit. In some cases, it is not possible to generate an appropriate auxiliary exposure pattern corresponding to the above exposure pattern. Furthermore, when the pattern density in the area is corrected according to the influence of the pattern density in the surrounding area, the distance between the areas and the distance between the actual pattern clumps may differ from each other. Cannot reflect the effect of In addition, even for subfields that are repeatedly arranged with the same exposure pattern, uniformly generating the area, correcting the pattern density, and generating the auxiliary exposure pattern are performed in a data processing step. Is unnecessarily long, which is not suitable for creating exposure data of a highly integrated LSI.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide a charged particle beam exposure method capable of creating exposure data capable of forming a pattern with higher precision and a charged particle beam carrying out the method. An object of the present invention is to provide a particle beam exposure apparatus.

Still another object of the present invention is to provide an exposure data capable of solving an inappropriate point due to a deviation between an area uniformly generated in a subfield and an actual exposure pattern. An object of the present invention is to provide a particle beam exposure method and a charged particle beam exposure apparatus that performs the method.

Further, another object of the present invention is to provide a charged particle beam exposure method capable of reflecting the influence of the pattern density of the surrounding area in accordance with the actual pattern position, and a charged particle beam carrying out the method. An exposure apparatus is provided.

Still another object of the present invention is to provide a charged particle beam exposure method capable of reducing the load of data processing on subfields repeatedly arranged with the same exposure pattern, and implementing the method. To provide a charged particle beam exposure apparatus.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method of exposing a pattern having pattern data for each of a plurality of subfields in a main field to an exposure having pattern data for each of the subfields. A charged particle beam exposure method for obtaining data and exposing a document in accordance with the exposure data; (a) generating a plurality of areas in the subfield; and (b) obtaining a pattern density in the area. Reviewing the pattern density according to the pattern density of the area around the area and the distance between the areas; and (c) when the reviewed pattern density of the area is lower than a predetermined exposure reference density,
Generating an auxiliary exposure pattern in the area;
And (d) exposing the material in accordance with exposure data obtained by adding the auxiliary exposure pattern data to the pattern data.

According to a first aspect of the present invention, when the distance between the pattern existing areas where the patterns are present is larger than a predetermined reference distance, the pattern density is higher than the exposure reference density between the pattern existing areas. The method further includes a step of generating an auxiliary exposure pattern in the area.

According to the first aspect of the invention, there is a mismatch between the exposure pattern and the area generated in the subfield, and the auxiliary exposure pattern is not generated when the determination is made simply according to the pattern density in the area. However, if the distance between the pattern existing areas is equal to or longer than a certain distance, the auxiliary exposure pattern can be generated. Therefore, even when matching between the exposure pattern and the area cannot be achieved, the auxiliary exposure pattern can be appropriately generated and an appropriate proximity exposure effect can be provided.

According to a second aspect, the auxiliary exposure pattern is:
It has a desired exposure distribution according to the resist material on the material.

According to the second aspect of the present invention, even when the spread characteristic of the exposure energy differs depending on the resist material,
An auxiliary exposure pattern having an exposure distribution according to the characteristics can be generated. Therefore, an optimum proximity exposure effect can be provided according to the resist material.

A third invention is characterized in that the step (a) generates a plurality of areas around a predetermined range symmetrically with respect to a point from the center of the area where the pattern exists in the subfield. .

According to the third aspect, by generating the area point-symmetrically from the center of the pattern existing area, mismatching between the exposure pattern and the area is prevented,
An auxiliary exposure pattern matching the exposure pattern can be generated.

According to a fourth aspect of the present invention, in the step (b), the pattern density in the area is obtained, and the pattern density is determined according to the pattern density of an area around the area and the distance between the pattern existing areas in the area. It is characterized by reviewing.

According to the fourth aspect, the influence of exposure from the pattern of the surrounding area is obtained from the distance between the pattern existing areas, so that the influence of exposure can be obtained more accurately. As a result, a more accurate auxiliary exposure pattern can be generated. Preferably, the distance between the pattern existing areas is a distance between the centers of gravity of the pattern existing areas.

According to a fifth aspect, when a plurality of subfields having the same pattern data are repeatedly arranged,
The steps (a) to (c) are performed on the first subfield of the subfields that are repeatedly arranged, and if no auxiliary exposure pattern is generated in the first subfield, at least the remaining subfields The method is characterized in that the steps (a) to (c) are omitted except for a partial region.

According to the fifth aspect, the operation speed can be reduced for subfields that are repeatedly arranged.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, such embodiments do not limit the technical scope of the present invention. Further, the present invention is applied to a charged particle beam exposure method and an apparatus therefor, and the following embodiments will be described by taking an electron beam exposure method and an apparatus therefor as an example.

FIG. 1 is a schematic configuration diagram of an electron beam exposure apparatus according to an embodiment of the present invention. In this example, the electron beam exposure apparatus uses design data Di having pattern data.
n, and exposure data Dou considering the proximity exposure effect
An exposure data generating device 100 for outputting t, an electron beam control device 200 supplied with the exposure data Dout to control the exposure device, and a lens barrel 300 are provided. Lens barrel 300
Inside, an electron gun 31, a rectangular transmission mask 32, a transmission mask 34 for exposure such as a block mask, and a mask deflector 3
X, Y stage 3 on which a lens 35, a focal lens 36, an electromagnetic deflector 37, an electrostatic deflector 38, and a wafer 40 are placed
9 are provided. The rectangular beam formed by the transmission mask 32 passes through a predetermined mask on the transmission mask selected by the mask deflectors 33 and 35, and is irradiated to a desired position on the wafer 40 by the deflectors 37 and 38.

Control signal S to mask deflectors 33 and 35
1. A control signal S for moving the transmission mask 34 in the horizontal direction
2, control signal S3 to the focal lens, electromagnetic deflector 3
7 and the control signal S to the electrostatic deflector 38.
5. The stage control signal S6 is transmitted to the electron beam controller 2
00 generated.

FIG. 2 shows the above-described exposure data creating apparatus 100.
FIG. 3 is a diagram showing an internal configuration of the device. A design data file 102 storing design data Din, an area generating unit 103 for generating an area in a subfield area, a pattern density generating unit 104 for calculating a pattern density in the area,
A pattern density correction unit 105 that corrects the pattern density in the area in consideration of the influence between the areas, a pattern density file 106 that stores the pattern density data in the area, and the exposure amount of the pattern in the area according to the pattern density An exposure amount correcting unit 107, an auxiliary exposure pattern generating unit 108 for generating an auxiliary exposure pattern in an area according to the pattern density, and an exposure data file 1 for storing exposure data.
09. These are processed by the arithmetic unit 1 via the bus 110.
11 is connected.

[Outline of Exposure Data Generation Method] An outline of a method of generating exposure data from design data will be described below. FIG. 3 is a diagram showing the relationship between the main field MF and the subfield SF in the semiconductor chip 10. Usually, a plurality of semiconductor chips 10 are formed on a semiconductor wafer. FIG. 3 shows a relationship between a main field and a subfield in the semiconductor chip 10. As shown in the exposure apparatus of FIG. 1, the electron beam deflector comprises an electromagnetic deflector 37 having a slow response speed but a large deflection range, and an electrostatic deflector 38 having a fast response speed but a narrow deflection range. The main field MF refers to a region that can be deflected by the electromagnetic deflector 37, and the subfield SF refers to a region that can be deflected by the electrostatic deflector 38.

By driving the X and Y stages 39 of the exposure apparatus, the wafer is moved to the center of a desired main field MF, and the electron beam is deflected by the electromagnetic deflector 37 in the main field MF to further form the desired shape. The deflected electron beam is deflected by the electrostatic deflector 38 and is irradiated to a desired position. In the example of FIG. 3, one main field 1
2 includes 5 rows and 5 columns of subfields SF00 to SF44.
Divided into

In the example of FIG. 3, in the main field 12, a single arrangement subfield SSF having a different pattern and a matrix arrangement subfield MSF repeatedly arranged with the same pattern are arranged. The matrix-arranged subfields MSF repeatedly arranged are subfields often found in, for example, a memory cell region of a memory device. On the other hand, the independently arranged subfield is a subfield found in a peripheral circuit, a logic circuit, or the like. As described above, the chip 10 is divided into a plurality of main fields and a plurality of subfields in each of the main fields, and the design data Din has pattern data existing in each of the subfields.

The subfields do not necessarily have to be laid without overlapping or without an interval as shown in FIG. 3, but may partially overlap or have an interval.

FIG. 4 is a diagram showing an example of the structure of design data relating to subfields in the main field 12 of FIG. In this example, subfields SF00 to SF44
Are the center coordinates (x,
y), the number of patterns n, and the pattern address ad.
In this example, the subfield data includes subfields SSF00, SSF01,.
.. MSF11, MSF12... SSF44.

On the other hand, the pattern data has, for example, lower left coordinates (x, y) of the pattern, and a width w and a height h of the pattern. The address “ad” in the subfield data area indicates an address in the pattern data, and means that the pattern of the address area of the number “n” of the patterns continuously from the address is the pattern data in each subfield. I do.

Therefore, the data of the single arrangement subfield SSF has different pattern data addresses. On the other hand, the data of the matrix arrangement subfield MSF has the same pattern data address. The data structure of this matrix arrangement subfield is referred to as a hierarchical data structure in this specification. With such a hierarchical data configuration, the data amount of the pattern data can be reduced.

FIG. 5 is a flowchart of an exposure process including the creation of exposure data. FIG. 6 is a diagram showing an example of a certain subfield SF. A method of creating exposure data will be described using the example of the subfield in FIG.

In step S11 in FIG. 5, an exposure amount Q according to the shape of each pattern is set. This exposure amount Q
Is set, for example, to be strong when the pattern shape is thin, and to be relatively weak when the pattern shape is thick or large. Then, the set exposure amount Q (not shown) is added to each pattern data. Although there are various methods for setting the exposure amount Q according to the pattern shape, they are omitted in the present embodiment because they are not essential.

Next, the hierarchical data is recognized from the design data consisting of all the subfields on the chip and its pattern data (S12). For example, whether the subfield has the attribute of the single arrangement subfield SSF, has the attribute of the matrix arrangement subfield MSF, has the attribute of the first original matrix arrangement subfield of the matrix arrangement subfield, and the like,
Confirmed from design data. Therefore, the attribute data ad (not shown) is added to the data of the subfield.

The design data only includes a pattern to be formed on the resist layer on the wafer. However, when the resist layer on the wafer is irradiated with an electron beam, a region having a high pattern density receives more beam energy due to the proximity exposure effect. On the other hand, in a region where the pattern density is low, there is no proximity exposure effect, and exposure is performed with less beam energy. Therefore, in consideration of the proximity exposure effect, the exposure amount of the pattern of the design data is reviewed, and if necessary, the auxiliary exposure is performed to positively generate the proximity exposure effect, thereby forming the pattern shape after development. It is necessary to increase the accuracy of In the present embodiment, in order to generate exposure data based on design data, a smaller map area is generated in a subfield,
Based on the pattern density in the area, the exposure amount is reviewed and an auxiliary exposure pattern is generated.

The subfield SF shown in FIG.
Patterns P1, P2, and P3 are included. Then, for each of the patterns P1, P2, and P3, the above-described step S1 is performed.
Exposure amounts Q1, Q corresponding to the respective pattern shapes at 1
2 and Q3 are set. Furthermore, areas a11 to a55 of 5 rows and 5 columns are generated in the subfield SF.
13). This area corresponds to the area generating unit 1 shown in FIG.
03. The area is generated by, for example, arranging regions of a predetermined size in a matrix on the basis of the lower left position of the subfield SF. Therefore, the end of the subfield does not always coincide with the end of the area.

In the example of FIG. 6, the pattern P1 is the area a2
1, a22, a31, a32, a41, and a42. Further, the pattern P2 is composed of the areas a13, a23, a
33, a43 and a53. Further, the pattern P
3 is an area a24, a25, a34, a35, a44,
a45.

In step S14, the pattern density in each area is determined. That is, it is obtained by the pattern density generation unit 104 in FIG. FIG. 7 is an example in which the pattern density Smn of each area of the subfield in the example of FIG. 6 is entered. That is, the ratio of the pattern area to the area area of the areas a32, a34, etc. is as high as 75%, and the pattern density of the area a11, etc., where no pattern exists, is 0%.

Next, in step S15, the pattern density in each area is reviewed according to the influence of the proximity exposure effect between the areas. The review of the pattern density is performed by the pattern density correction unit in FIG. Due to the proximity exposure effect, the energy of the electron beam applied to the pattern in the area located around the area has an effect on the area according to the distance between the areas. The effect is greater from an area at a closer position, and is less affected from an area at a farther position. Therefore, in the present embodiment, a coefficient β (r) (r is a distance between areas) which is substantially inversely proportional to the distance is set in advance, and the pattern density Smn of the surrounding area is multiplied by the coefficient β (r). Then, it is added to the pattern density of the area of interest.

FIG. 8 is a diagram for explaining the pattern density review in response to the influence of the proximity exposure effect between the areas. This example is an example of reviewing the pattern density of the area a33. Area a 33
The influence of the proximity exposure effect from the areas a11 to a55 around 33 is added. For example the area a11, since pattern density is 0% (= S _11), the effect is, S ₁₁ × beta
(R (a ₁₁ −a ₃₃ )) = 0. The r (a ₁₁ -a _33), indicating the distance between the centers between the areas a11 and a33. The area a12 is also 0. And area a
13 has a pattern density of 25% (= S ₁₃ ),
The degree of influence is S ₁₃ × β (r (a ₁₃ −a ₃₃ )).
Similarly, the processing is performed for the areas a14 to a55. As a result, the pattern density of the area a33 is corrected from 50% to, for example, 60%.

The area a33 has an area with a high pattern density at a position close to the area a33. Therefore, the energy of the electron beam applied to the surrounding area greatly affects the area a33. When considering the impact of this proximity exposure effect, substantial pattern density SR ₃₃ area a33 has a value density [Delta] S ₃₃ is added by the influence from the surroundings on their own pattern density S _33.

FIG. 9 is a diagram showing the pattern density in each area after the result of reviewing the pattern density in the above-mentioned area. For example, an area having a high pattern density around the area has a high pattern density of about 10%, and an area where no such area exists around the area.
For example, the pattern density is increased by about 5%.
Note that the influence from the area in the adjacent subfield is added to the area located around the subfield SF such as the area a11 in the same manner as described above.

Step S16 is a step of detecting a pattern existing area in a high-density subfield. This step will be described later in the section of an auxiliary exposure pattern generation step.

As shown in FIG. 9, when the pattern density of each area is reviewed, the exposure amount of each of the patterns P1, P2, and P3 is corrected based on the revised pattern density SRmn (S17). And an auxiliary exposure pattern is generated (S18).

In step S11, patterns P1, P
While the exposure amount Q is set according to the shape of each of P2 and P3, in the correction of the exposure amount in step S17,
The exposure amount is corrected in consideration of the influence of the proximity exposure effect from the surrounding pattern. For that purpose, the substantial pattern density for each area reviewed in step S15 is used. That is, when the substantial pattern density SRmn is higher than the reference value, the exposure of the pattern belonging to the area is reduced because the proximity exposure effect is greatly affected.

On the other hand, if the substantial pattern density SRmn for each area, which has been reviewed in step S15, is lower than the reference value, the effect of the proximity exposure effect is small. An exposure pattern is generated and added to the exposure data. Here, the auxiliary exposure pattern is an exposure pattern for giving an amount of energy corresponding to the proximity exposure effect to a region having a low pattern density, and a uniform exposure amount of, for example, about several% of the exposed energy is uniform. Is an exposure pattern to be provided. The size of the auxiliary exposure pattern is preferably about the size of an area.
However, the position of the auxiliary exposure pattern does not necessarily need to be the same as the area generated in the pattern density review.

FIG. 10 shows the above-described exposure amount correcting step (S1).
FIG. 7 is a diagram showing an example of a correction table used in 7) and an auxiliary exposure pattern generation step (S18). In this example, the pattern density SRmn of the area is divided into 11 levels, and the exposure correction ratio α of each division and the auxiliary exposure pattern are shown. In this example, the reference value is 45.5.
%, And when the pattern density of the area is larger than the reference value, the exposure amount Q of the pattern of the area is multiplied by the ratio α in FIG. That is, the pattern density SRmn is 9
The exposure amount of the pattern in the area exceeding 0.5% is obtained by multiplying the set exposure amount Q by the ratio α = 0.1. Similarly,
Area pattern density SRmn is 81.5 to 90.5%
In the case of, the set exposure amount Q is multiplied by the ratio α = 0.2.

On the other hand, if the pattern density of the area is lower than the reference value, it means that the density in the vicinity of the area is low, and the developed pattern after exposure becomes thin. Therefore, in such an area, an auxiliary exposure pattern is generated as exposure data in order to perform the auxiliary exposure. In the example of FIG. 10, auxiliary exposure patterns for performing auxiliary exposures 1 to 5 are generated for stages 1 to 5 where the pattern density is low. The auxiliary exposure 1 has a larger exposure amount, and the auxiliary exposure 5 has an auxiliary exposure pattern with a smaller exposure amount. The auxiliary exposure pattern is a pattern having the same size as the area.

FIG. 11 is a diagram showing a subfield in a case where the exposure amount of a pattern in an area having a high pattern density is reduced and an auxiliary exposure pattern is generated in an area having a low pattern density. In this example, areas a22, a32, a23, a33, a43, a
The exposure amount Q of the patterns P1, P2 and P3 belonging to 24, a34 is reduced by multiplying by the ratio α. Further, areas a11 to a21, a25, and
Auxiliary exposure patterns (thick lines) are generated at a31, a35 to a42, and a44 to a55.

In the example of FIG. 11, the area generated for obtaining the pattern density is used as it is as the area of the auxiliary exposure pattern. However, the area of the auxiliary exposure pattern may be different from the area for generating the pattern density.

As shown in FIG. 5, an area is similarly generated for each subfield to determine the pattern density.
The pattern density is reviewed under the influence of the surrounding area, and the pattern exposure amount Q is corrected and the auxiliary exposure pattern is generated using the pattern density as an index. As a result, exposure data is created.

FIG. 12 is a diagram showing a configuration example of the created exposure data. First, in the design data of FIG. 4, the pattern data is the position data (x, y), the width w, and the height h.
Whereas, the pattern data of the exposure data is
Further, it has an exposure amount Q. The exposure amount Q is a value that is initially set according to the shape of the pattern (S11) and is corrected using the pattern density of the area. Second, the design data of FIG. 4 does not have attribute data such as a single arrangement subfield, a matrix arrangement subfield, and its original subfield as subfield data. The attribute data at is added in the hierarchical data recognition step (S12). Third, the design data is stored in the subfield SSF00.
To SSF44 and the pattern data of the subfields. However, the exposure data has subfields TSSF1 to TSSFn for auxiliary exposure having an auxiliary exposure pattern as subfields.

In order to maintain the hierarchical structure of the subfield data and the pattern data, the auxiliary exposure pattern is defined as an exposure pattern in the temporary single arrangement subfields TSSF1 to TSSFn which is a kind of the newly added single arrangement subfield. Registered in exposure data. In FIG.
After the single arrangement subfield SSF44, temporary single arrangement subfields TSSF1 to TSSFn are added.
This temporary single arrangement subfield has an auxiliary exposure pattern of the size of the area. Since the auxiliary exposure pattern in each temporary single placement subfield is not repeated,
The properties of the temporary single arrangement subfield are equivalent to those of the single arrangement subfield. Therefore, as the exposure data, the single placement subfield and the temporary single placement subfield are handled in the same manner. Note that a plurality of auxiliary exposure patterns are generated in the temporary single arrangement subfield.

As shown in FIG. 3, the sub-field is not necessarily an area laid all over the main field, but may be an area partially overlapping each other according to the internal exposure pattern. In the exposure step, the position of each subfield is simply irradiated with an electron beam onto the exposure pattern included in that subfield. Therefore, the subfield of the auxiliary exposure pattern may be registered so as to overlap the subfield of the exposure pattern. This makes it possible to add the auxiliary exposure pattern to the exposure data without breaking the hierarchical data structure.

As described above, the exposure amount of the pattern of the temporary single arrangement subfield added to the subfield of the design data is insufficient to expose the resist by itself.

Then, the exposure data Dout created in this way is supplied to the electron beam controller, and the electron beam exposure is performed according to the exposure data (S20).

A feature of the above-described method of creating exposure data is that an area is generated in a subfield in order to create exposure data in consideration of a proximity exposure effect depending on an exposure density and a distance. Then, based on the substantial pattern density SRmn obtained by adding the proximity exposure effect from the surrounding area to the pattern density Smn of the area, the exposure amount is corrected and the auxiliary exposure pattern is generated. Then, the auxiliary exposure pattern is not the pattern data in the existing subfield, but the pattern data of the newly generated temporary single arrangement subfield.

However, in the above method, since the area is generated in the subfield irrespective of the internal pattern shape and position, various problems arise due to the area. Further, since the shape of the auxiliary exposure pattern is made to be the shape of the area generated irrespective of the actual pattern shape and position, the auxiliary exposure pattern may be different from an ideal auxiliary exposure pattern that can solve the problem of the proximity exposure effect. Hereinafter, each problem will be described in detail, and the solution will be described.

[Generation of Auxiliary Exposure Pattern Between Pattern Existence Areas] FIG. 13 shows a matrix arrangement subfield MS.
FIG. 9 is a diagram illustrating an example of an auxiliary exposure pattern generated in an area in F. The matrix arrangement subfield MSF is typically a subfield in which the same pattern is repeatedly exposed at a high density like a memory cell region. In such subfields, regions 41 to 4 where patterns exist
5 are arranged at regular intervals. That is, there are pattern breaks 51 to 54 between the pattern existing regions 41 to 45. The area of the area a _mn generated in the subfield does not match the pattern existing areas 41 to 45, and the area of the area matches at the cuts 51 and 53, but the area of the area at the cuts 52 and 54 does not match. Does not match.

In such a situation, if a method is used in which an auxiliary exposure pattern is generated in an area with a low pattern density and no auxiliary exposure pattern is generated in an area with a high pattern density, based on the pattern density for each area described above, The auxiliary exposure pattern is generated in the area of the thick frame 13 and the auxiliary exposure pattern is not generated in the area of the thin frame. Therefore, although all of the cuts 51 to 54 have the same exposure pattern arrangement, there is a problem that the auxiliary exposure pattern is generated or not generated depending on the consistency with the area. As a result, since the auxiliary exposure pattern is generated in the area A1 in FIG. 13, the problem of thinning of the developed pattern does not occur, but the auxiliary exposure pattern is not generated in the area A2 and the developed pattern is not generated. The problem of thinning occurs.

In the present embodiment, in order to solve the problem of the auxiliary exposure pattern generation method based on the pattern density of the area, data of the pattern existing area in the area is generated. However, when the distance between adjacent pattern existing regions exceeds a certain distance, for example, about the size of an area, an auxiliary exposure pattern is generated in such an area.

FIG. 14 is an enlarged view of the area A2 in FIG. In this figure, six areas a _mn
It is shown. FIG. 15 is a diagram illustrating an example of the area data. In this example, when the areas a _{11 to} a _ij exist in the subfield SF _mn , each area is defined as area data, area position data, lower left and upper right position data of a pattern existing area in the area, and It has pattern density data, revised pattern density data, flag data indicating whether or not an auxiliary exposure pattern has been generated, and flag data indicating whether the area is within a matrix arrangement subfield.

That is, when the area a _mn is generated in the matrix arrangement subfield, the data of the area where the pattern in each area a _mn exists is generated.

Therefore, first, an auxiliary exposure pattern is generated as described above according to the review pattern density in the area,
Thereafter, the pattern existence area is recognized with reference to the area data. When the pattern existing region 41 to 45 in the sub-fields are recognized, with respect to the surrounding area thereof to calculate the distance L ₁ to the pattern existing region adjacent. As shown in FIG. 14A, the pattern existing area 4
It is greater than the reference distance L _ref which is a distance L ₁ between 2, 43 generates an auxiliary exposure pattern near the area.

The reference distance _Lref can be determined according to the proximity exposure effect. For example, the reference distance _Lref is preferably about the size of one area which is a unit in which an auxiliary exposure pattern can be generated. That is, an auxiliary exposure pattern is newly generated in an area where an area having a low pattern density may be generated depending on the matching between the area position and the pattern existing area.

FIG. 14B shows a state in which the auxiliary exposure pattern 60 has been generated in six areas a _mn . An auxiliary exposure pattern 60 in a hatched portion in the figure is newly generated.

FIG. 16 is a diagram showing a matrix arrangement subfield when a new auxiliary exposure pattern is generated. An auxiliary exposure pattern is generated in a thick line area. As is apparent from comparison with FIG.
Break 52 between 2 and 43, and pattern existence area 4
A new auxiliary exposure pattern has been generated at the break 54 between the lines 4 and 45. As a result, in the case of FIG.
In the case of FIG. 16, an auxiliary exposure pattern is generated in the area around the pattern existing area, and there is no difference between the developed patterns in areas A1 and A2. Thus, a development pattern having an appropriate size can be obtained.

FIG. 17 is a flow chart of the above-described auxiliary exposure pattern generation. This flowchart is shown in FIG.
Step S18 will be described in detail. As mentioned above,
According to the correction table shown in FIG. 10, an auxiliary exposure pattern having an exposure amount corresponding to the pattern density in the area is generated and registered in the temporary single arrangement subfield (S31).
After that, the area around the pattern existing area in the matrix arrangement subfield is recognized (S32). Then, for those areas, it is greater than the distance L ₁ is the reference distance L _ref to pattern exists adjacent areas (S33), an auxiliary exposure pattern occurs in the area,
Additional registration is made in the temporary single arrangement subfield (S34).

[Generation of Stepwise Auxiliary Exposure Pattern] In the generation of an auxiliary exposure pattern, a proximity exposure effect is positively generated by exposing a region having a low exposure pattern density with energy that does not lead to development. This prevents a pattern having no exposure pattern in the periphery from becoming thin after development. The proximity exposure effect occurs when the energy of the electron beam applied to the resist layer spreads around. Then, by generating an auxiliary exposure pattern in a region having a low pattern density, the energy of the electron beam applied to the auxiliary exposure pattern is spread, thereby giving energy of the proximity exposure effect to the adjacent original exposure pattern. Therefore, the generation of the auxiliary exposure pattern is based on a certain degree of diffusion of the energy of the electron beam in the auxiliary exposure.

The spread of the energy of the electron beam is as follows.
It depends on the material of the resist. Usually, the most suitable material for the resist is used according to the fineness and density of the pattern to be formed. Therefore, in an electron beam exposure apparatus, generation of an auxiliary exposure pattern applicable to resists of different materials is required.

FIG. 18 is a diagram showing a state in which an auxiliary exposure pattern is generated around an exposure pattern. In this example, in a region having the exposure patterns 61 to 64, the auxiliary exposure patterns 71 are generated around the exposure patterns 61 to 64. FIG. 18 does not show the area generated for simplicity. In the example of FIG. 18, the auxiliary exposure pattern 71 is generated in a region where the pattern density is low, based on the pattern density of the generated area.

In the case of a resist made of a material having a certain electron beam spread characteristic, the irradiation of the auxiliary exposure pattern 71 with the electron beam spreads its energy to the exposure patterns 61 to 64 to prevent the pattern from becoming thin. be able to. However, in contrast, in the case of a resist made of a material having poor electron beam spreading characteristics, the position of the auxiliary exposure pattern 71 in the drawing is far from the exposure patterns 61 to 64, so that a sufficient proximity exposure effect can be obtained for the exposure pattern. Cannot be caused.

Therefore, in this embodiment, the area where the auxiliary exposure pattern is generated is changed according to the characteristics of the resist material.
Expand not only the area with low pattern density but also that area and its surrounding area. In addition, when the resist is spread to the surrounding area, the exposure amount Q is set stepwise so as to obtain a spread distribution in the case of a resist having ideal spread characteristics. Then, the total exposure amount is set equal to the case where the area is not expanded.

FIG. 19 shows an example of a ratio table in consideration of the spread characteristic of the auxiliary exposure pattern. In this example, when the auxiliary exposure pattern 75 is generated at the center of the area of 7 rows and 7 columns, the auxiliary exposure pattern 76 in consideration of the spread is shown.
This shows that the energy distribution changes from 75 to 76. And even if it spreads, the total energy needs to be equal to the energy of the auxiliary exposure pattern generated in a single area.

[0077] In the matrix of FIG. 19, the ratio S ₁₁ ~
_S77 is shown, and their ratios satisfy the following equation:

1.0 = S ₁₁ / (S ₁₁ + S ₁₂ + _... + S ₆₇ + S ₇₇ ) + _... + S ₇₇ / (S ₁₁ + S ₁₂ + _... + S ₆₇ + S ₇₇ ) As is clear from FIG.
Depending on the material of the resist, it is necessary to generate an auxiliary exposure pattern having a stepwise exposure amount so as to be 6.

FIG. 20 is a diagram showing an example in which the auxiliary exposure pattern of FIG. 18 is changed to an auxiliary exposure pattern having a stepwise exposure amount distribution. In addition to the auxiliary exposure pattern 71 of FIG. 18, an additional auxiliary exposure pattern 72 is generated between the exposure patterns 61 to 64 and the auxiliary exposure pattern 71. The exposure amount of the additional auxiliary exposure pattern 72 is
It is set to be weaker than 1, so that the total exposure amount does not increase. In the example of FIG. 20, the exposure amount of the auxiliary exposure pattern 71 is weaker than in the case of FIG. 18, and the exposure amount of the additional auxiliary exposure pattern 72 is further weaker.

In an actual exposure apparatus, a case where only the auxiliary exposure pattern 71 shown in FIG. 18 is generated and a case where the auxiliary exposure patterns 71 and 72 shown in FIG. 20 are generated can be selected according to the resist material used. I do. Further, when the number of types of resist increases, it is possible to generate auxiliary exposure patterns having a plurality of types of stepwise exposures having different degrees of spread.

The generation of the above auxiliary exposure pattern is shown in FIG.
Is also shown in the flowchart of FIG. In step S36, if it is necessary to generate a stepwise auxiliary exposure pattern depending on the material of the resist to be used and consequently to have a spreading characteristic, the generated auxiliary exposure pattern is set to a stepwise exposure amount. To the auxiliary exposure pattern (S
37). Therefore, the changed auxiliary exposure pattern becomes a pattern having more areas. The auxiliary exposure pattern changed in this manner is added as pattern data in the temporary single arrangement subfield as described above. Therefore, the exposure amount of the pattern data has a stepwise distribution.

FIG. 21 is a diagram showing an exposure amount distribution of the auxiliary exposure pattern of FIG. 21 is an exposure distribution along the vertical direction in FIG. 20. Exposure patterns 61 to 6 to be originally developed
4 has a high exposure amount, while the auxiliary exposure pattern 71 has a lower exposure amount. Further, the added auxiliary exposure pattern 72 has an even lower exposure.

[Generation of Area Matching Pattern] In the present embodiment, an area is generated in a subfield, the pattern density in the area is obtained, and the influence of the pattern of the surrounding area is taken into consideration. A new pattern density is obtained, and an auxiliary exposure pattern is generated based on the revised new pattern density. Moreover, the auxiliary exposure pattern is a pattern in units of areas.

However, the consistency between the exposure pattern to be actually developed and the auxiliary exposure pattern in units of areas is poor, and different auxiliary exposure patterns may be generated even for the same exposure pattern.

FIG. 22 is a diagram showing an auxiliary exposure pattern generated for an exposure pattern in a subfield.
In this example, three exposure patterns PA, PB, and PC exist in the subfield SF, and an auxiliary exposure pattern indicated by a thick line is generated in a region surrounding the three exposure patterns PA, PB, and PC. Each auxiliary exposure pattern has a size covering an area of 12 rows and 3 columns.

As shown, the exposure patterns PA, PB, and PC are under the same exposure density condition. However, the pattern PA is located at the left end of the area, and the pattern P
B is located at the center of the area, and the pattern PC is located at the right end of the area. As a result, the auxiliary exposure pattern generated for the pattern PB is symmetric with respect to the pattern PB. On the other hand, the auxiliary exposure patterns generated for the patterns PA and PB are not symmetric with respect to the patterns PA and PC. This inconvenience is caused by the generation of an area without depending on the position of the exposure pattern.

Therefore, in this embodiment, an area is generated which depends on the position of the existing pattern. For that,
An area where a pattern exists is obtained, and an area is generated around the area in a point-symmetric manner from the center or the center of gravity of the pattern existing area. Moreover, the generation around the area is limited to the range where the proximity exposure effect occurs. Areas outside of this area do not need to generate an auxiliary exposure pattern in the first place since the pattern itself does not exist even if an area is originally generated, so there is no need to generate the area itself.

FIG. 23 is a diagram showing a method of detecting the area where the exposure pattern exists in the subfield. FIG. 24 is a diagram illustrating a method of generating an area that matches a detected pattern existing area. The example of FIG. 23 is an example in which a cluster of two patterns exists in the subfield SF.

First, as shown in FIG. 4, the pattern data has a lower left coordinate (x, y) of the pattern, a width w and a height h of the pattern. Therefore, when an area is generated in the target subfield SF, the pattern data in the subfield SF and the pattern data in the adjacent subfield are read from the design data. Then, as shown in FIG. 23, since the patterns p01 and p02 are adjacent to each other, a pattern existing area A01 is created by combining them. Further, the pattern existing area A01 and the adjacent pattern p03 are synthesized.
In that case, the respective widths A01W and p03W are compared, and the larger width p03W is set to the new pattern existing area A.
02 width.

By performing the above algorithm on all the read pattern data, two pattern existence areas 82 and 83 are created in the subfield SF as shown by a broken line in FIG. In this example, the pattern existing areas 82 and 83 are out of the area of the subfield SF. In generating a pattern existing area by synthesizing a plurality of patterns, the plurality of patterns need not be adjacent to each other, and can be synthesized as a pattern existing area even when they are close to each other within a predetermined distance. .

FIG. 24 shows the above-mentioned pattern existing area 82,
83 shows a state in which areas matching each other have been generated. With the centers 82C and 83C of the two pattern existence areas 82 and 83 created in the subfield SF as starting points, point symmetric areas a _mn are respectively generated. In that case, generation region of the area, it Hirogare from the pattern existing region 82 and 83 up to the exposure influence range L _2.
In the example of FIG. 24, both pattern existence areas 82 and 83
It is present at a distance of more than 2 times the exposure influence range L _2. Therefore, the areas generated in the respective pattern existence areas 82 and 83 do not overlap.

Although there is a region in the subfield SF where no area is generated, the exposure is not affected in the first place, the pattern density of the region becomes zero, and the generation of the auxiliary exposure pattern is unnecessary. There is no problem.

[0093] The pattern existing region 82 and 83, when approximated within 2 times the exposure influence range L ₂ combines them to generate a new pattern existing region, the respective areas It is possible to prevent the auxiliary exposure pattern from being duplicated. Alternatively, if the areas generated in the two pattern existence areas overlap, the flag indicating whether the auxiliary exposure pattern of the area data shown in FIG. Generation of a new auxiliary exposure pattern can be prohibited. Alternatively, since the exposure amount of the auxiliary exposure pattern itself is small, it is possible to allow a certain degree of overlapping of the auxiliary exposure patterns and perform data processing so that the total exposure amount of the target area does not exceed a certain threshold.

As shown in FIG. 24, by generating an area that matches each pattern existing area, an auxiliary exposure pattern whose area is a unit of generation matches the pattern and can avoid the adverse effects shown in FIG. .

[Inter-area Proximity Exposure Effect] The auxiliary exposure pattern generation method in consideration of the proximity exposure effect in the present embodiment is performed based on the pattern density of the area generated in the subfield. The pattern density in this area is obtained by adding the density of the actually existing pattern and the degree of influence given by the proximity exposure effect from the pattern in the surrounding area as the pattern density. In that case, FIG.
As shown in the above, in order to detect the degree of exposure influence from the pattern of the surrounding area, the coefficient of the exposure pattern density of the surrounding area by the distance r to the target area, for example, 1 /
Multiply (1 + r).

FIG. 25 shows an area AREA11 of three rows and three columns.
~ AREA33, the middle area AREA22
FIG. 9 is a diagram showing detection of the degree of the influence of exposure to light. In this example, the distance between the areas is simply defined as the distance between the centers of the areas. However, in practice, the patterns in the area do not exist uniformly in the area. FIG.
In the example of 5, the area AREA11 has a pattern at the lower right, and the area AREA22 has a pattern at the right end. Therefore, if the exposure influence degree from the surrounding area is determined using the distance between the centers of the areas, the actual exposure influence degree cannot be accurately determined.

Therefore, in the present embodiment, in order to more accurately determine the degree of exposure influence from a pattern in a surrounding area, a pattern existing area is detected for each area, and the distance between the centers of gravity of the pattern existing area (or Use the distance between centers. As described with reference to FIG. 15, each area data includes, in addition to the position coordinates of the area, lower left coordinates and upper right coordinates data of the area where the pattern exists. Therefore, the area where this pattern exists is used as the pattern existing area, and the distance between the centers of gravity of the area is used as the distance between the areas.

FIG. 26 is a diagram showing a case where the distance between the pattern existing areas in the area is used. In this example, areas AREA 11, 12, 13, 21, 22 and ARE
A23 and A33 only have a single pattern, and areas AREA32 and AREA have a plurality of patterns. Therefore, in the areas AREA11 to 22 and the like, the pattern itself becomes the pattern existence area PE. Also, AR
In the EAs 32 and 13, a rectangular area where a plurality of patterns exist is used as a pattern existing area PE and the center of gravity of the area is used.

Therefore, as shown in FIG. 26, the position of the target area AREA 22 is regarded as the position of the center of gravity of the pattern (same as the center position of the pattern). Using this, the degree of exposure influence is calculated and the pattern density is corrected.
As a result, the degree of exposure influence can be detected more accurately, and the pattern density of an area serving as a reference for generating an auxiliary exposure pattern can be generated more accurately.

[Operation of Matrix Arrangement Subfield]
The matrix arrangement subfield occurs in a region having only a repetitive pattern, such as a memory cell region of an integrated circuit. In this case, the matrix arrangement subfield which occurs repeatedly includes a subfield (matrix reference arrangement subfield) which is a reference at the head of the exposure order, and is followed by a matrix arrangement subfield indicating the address of the same pattern data. Exists. And
In the periphery of the matrix-arranged area, a single arrangement sub-field is adjacent or partially overlapped.

In general, a matrix arrangement subfield generated in a high-density region such as a memory cell region has a high-density pattern inside. Therefore, it is often unnecessary to generate an auxiliary exposure pattern in such a matrix arrangement subfield.

Therefore, in the present embodiment, step S1 shown in FIG.
If the auxiliary exposure pattern is not generated by performing the calculations in S3 to S18, it is determined that no auxiliary exposure pattern will be generated in the subsequent matrix arrangement subfields, and the pattern data is read from these matrix arrangement subfields and the operation is performed. Absent. However, since the pattern density is often low at the boundary portion of the matrix arrangement sub-field, pattern data is read in such a region, the pattern density is detected, and an auxiliary exposure pattern is generated as necessary.

FIG. 27 is a diagram showing an example of a matrix arrangement subfield when the above example is applied. In this example, the matrix arrangement subfield MSF has 5 rows and 5 rows.
Columns are arranged in a repeating manner. Then, the first matrix arrangement subfield becomes the matrix reference arrangement subfield MRSF. Around the matrix arrangement subfield, the single arrangement subfield SSF is arranged so as to partially overlap. Then, the temporary single arrangement subfield KSSF is provided in a region (the field indicated by a broken line in the drawing) matching the single arrangement subfield.

In this example, in order to minimize the calculation time for generating the auxiliary exposure pattern in consideration of the proximity exposure effect, the matrix reference arrangement subfield MRSF
Then, an area is generated, the pattern is read, the pattern density of the area is obtained, and it is determined whether or not an auxiliary exposure pattern is necessary. In the case of a high density matrix arrangement subfield, generation of an auxiliary exposure pattern is almost unnecessary.

Therefore, if priority is given to shortening the operation time even if the exposure accuracy slightly decreases, an operation is performed to determine whether or not an auxiliary exposure pattern is necessary only for the matrix reference arrangement subfield MRSF. Is unnecessary, the calculation of the remaining matrix arrangement subfields is omitted. The ratio α for reducing the exposure amount of the portion having a high pattern density is determined by the matrix reference arrangement subfield MRS.
The ratio α obtained in F is also applied to the remaining matrix arrangement subfields.

However, in the case of a matrix-arranged subfield, since the pattern density may be sparse at the boundary portion, the pattern data in the area 90 in the figure is read, and the pattern density in the area is obtained. Then, it is determined whether or not the generation of the auxiliary exposure pattern is necessary. The calculation time is shortened by reducing the amount of pattern data to be read. The area 90 includes a matrix arrangement subfield MSF.
In the same manner, it is necessary to read the pattern data in the vertical boundary area of the matrix arrangement subfield MSF.

[0107]

As described above, according to the present invention, when generating the charged particle beam exposure data, an area is generated in the subfield to determine the pattern density of the area, and the auxiliary exposure pattern is formed according to the pattern density. When this occurs, even if the exposure pattern and the area cannot be matched, it is possible to generate an auxiliary exposure pattern that is optimal for the exposure pattern.

According to the present invention, even when the exposure pattern and the area cannot be matched as described above,
Since the auxiliary exposure pattern can be added by checking the distance between the exposure patterns, it is possible to prevent a phenomenon in which the proximity pattern effect is insufficient and the developed pattern is thinned.

Further, according to the present invention, even when the auxiliary exposure pattern is uniformly generated in the area size as described above, the auxiliary exposure pattern having a stepwise exposure amount distribution is appropriately formed according to the material of the resist. Since it can be generated, the proximity exposure effect optimal for the material of the resist can be generated.

Further, according to the present invention, the problem of mismatch between the exposure pattern and the area can be solved by generating an area from the center of the area of the exposure pattern to the surrounding area.

Further, according to the present invention, when the pattern density of an area is obtained and the pattern density is reconsidered in consideration of the exposure effect from the pattern of the surrounding area, the distance between the pattern existence areas in the surrounding area is determined. Since the degree of influence can be obtained, it is possible to generate a more accurate auxiliary exposure pattern.

Further, according to the present invention, in the matrix arrangement subfield, the above operation need only be performed for the first reference matrix arrangement subfield, and the operation of the remaining matrix arrangement subfield is omitted. Therefore, the calculation time for obtaining the exposure data from the design data can be shortened.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electron beam exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an internal configuration of the exposure data creating apparatus 100.

FIG. 3 is a diagram showing a relationship between a main field MF and a subfield SF.

FIG. 4 is a diagram showing a configuration example of design data for a subfield in the main field of FIG. 3;

FIG. 5 is a flowchart of an exposure process including creation of exposure data.

FIG. 6 is a diagram illustrating an example of a certain subfield SF.

7 is an example in which a pattern density Smn for each area of the subfield in the example of FIG. 6 is entered.

FIG. 8 is a diagram for explaining a pattern density review in accordance with the effect of the proximity exposure effect between areas.

FIG. 9 is a diagram showing the pattern density in each area after the result of reviewing the pattern density in the area;

FIG. 10 is a diagram illustrating an example of a correction table used in a correction process of an exposure amount and a generation process of an auxiliary exposure pattern.

FIG. 11 is a diagram showing subfields when the exposure amount of a pattern in an area having a high pattern density is reduced and an auxiliary exposure pattern is generated in an area having a low pattern density.

FIG. 12 is a diagram illustrating a configuration example of created exposure data.

FIG. 13 is a diagram showing an example of an auxiliary exposure pattern generated in an area within a matrix arrangement subfield MSF.

FIG. 14 is an enlarged view of a portion of an area A2 in FIG. 13;

FIG. 15 is a diagram illustrating an example of area data.

FIG. 16 is a diagram showing a matrix arrangement subfield when a new auxiliary exposure pattern is generated.

FIG. 17 is a flowchart of generation of an auxiliary exposure pattern.

FIG. 18 is a diagram showing a state in which an auxiliary exposure pattern is generated around an exposure pattern.

FIG. 19 shows an example of a ratio table in which the spread characteristic of an auxiliary exposure pattern is considered.

20 is a diagram illustrating an example in which the auxiliary exposure pattern of FIG. 18 is an auxiliary exposure pattern having a stepwise exposure amount distribution.

21 is a diagram showing an exposure amount distribution of the auxiliary exposure pattern of FIG. 21 is an exposure distribution along the vertical direction in FIG. 20.

FIG. 22 is a diagram showing an auxiliary exposure pattern generated for an exposure pattern in a subfield.

FIG. 23 is a diagram illustrating a method of detecting an area where an exposure pattern exists in a subfield.

FIG. 24 is a diagram illustrating a method of generating an area that matches a detected pattern existence area.

FIG. 25 shows areas AREA11 to AREA3 of 3 rows and 3 columns.
FIG. 3 is a diagram illustrating detection of the degree of exposure influence on a middle area AREA22 in No. 3;

FIG. 26 is a diagram illustrating a case where a distance between pattern existing regions in an area is used.

FIG. 27 is a diagram illustrating an example of a matrix arrangement subfield.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 Exposure data creation device 200 Beam control device 300 Lens tube MF Main field SF Subfield SSF Single arrangement subfield MSF Matrix arrangement subfield, Subfield repeatedly arranged

Claims (14)

[Claims] 1. A charged particle beam exposure method for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for a plurality of subfields in a main field, and exposing a material in accordance with the exposure data. (A) a step of generating a plurality of areas in the subfield; and (b) determining a pattern density in the area, and calculating the pattern density according to the pattern density of the area surrounding the area and the distance between the areas. Reviewing; (c) generating an auxiliary exposure pattern in the area when the revised pattern density of the area is lower than a predetermined exposure reference density; and (d) existence of a pattern in which the pattern exists. If the distance between the areas is larger than the predetermined reference distance, A step of further generating an auxiliary exposure pattern in an area having a pattern density higher than the exposure reference density; and (e) exposing the material according to exposure data obtained by adding the auxiliary exposure pattern data to the pattern data. A charged particle beam exposure method, comprising: 2. The method according to claim 1, wherein, in the step (b), pattern existing area data in the area is generated, and in the step (d), the pattern existing area data of each of the generated areas is obtained. A charged particle beam exposure method, wherein a distance between the pattern existing regions is obtained. 3. A charged particle beam exposure method for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material according to the exposure data. (A) a step of generating a plurality of areas in the subfield; and (b) determining a pattern density in the area, and calculating the pattern density according to the pattern density of the area surrounding the area and the distance between the areas. Reviewing; (c) generating an auxiliary exposure pattern in the area when the revised pattern density of the area is lower than a predetermined exposure reference density, wherein the auxiliary exposure pattern is formed of a resist material on the material. Having a desired exposure distribution according to the following: (d) the auxiliary exposure to the pattern data Exposing the material in accordance with the exposure data to which the pattern data has been added. 4. The charged particle beam exposure method according to claim 3, wherein the exposure amount distribution of the auxiliary exposure pattern can select an optimum value according to the degree of spread of exposure energy in the resist material. . 5. A charged particle beam exposure method for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for a plurality of subfields in a main field, and exposing a material in accordance with the exposure data. (A) a step of generating a plurality of areas around a predetermined range in point symmetry from the center of a pattern existing area in the subfield; and (b) obtaining a pattern density in the area. Reviewing the pattern density according to the pattern density of the area around the area and the distance between the areas; and (c) assisting the area within the area when the reviewed pattern density of the area is lower than a predetermined exposure reference density. Generating an exposure pattern; and (d) adding the auxiliary exposure pattern data to the pattern data. Exposing the material according to the exposure data. 6. A charged particle beam exposure method for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for a plurality of subfields in a main field, and exposing a material according to the exposure data. (A) generating a plurality of areas in the sub-field; and (b) determining a pattern density in the area, and determining a pattern density between an area surrounding the area and a pattern existing area in the area. Reviewing the pattern density according to the distance; (c) generating an auxiliary exposure pattern in the area when the reviewed pattern density of the area is lower than a predetermined exposure reference density; According to the exposure data obtained by adding the auxiliary exposure pattern data to the pattern data, the material is exposed. A charged particle beam exposure method. 7. The charged particle beam exposure method according to claim 6, wherein a distance between pattern existing regions in the area is a distance between the centers of gravity of the pattern existing regions. 8. A charged particle beam exposure method for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material according to the exposure data. (A) a step of generating a plurality of areas in the subfield; and (b) determining a pattern density in the area, and calculating the pattern density according to the pattern density of the area surrounding the area and the distance between the areas. Reviewing; (c) generating an auxiliary exposure pattern in the area when the revised pattern density of the area is lower than a predetermined exposure reference density; and (d) applying the auxiliary exposure to the pattern data. Exposing the material in accordance with the exposure data to which the pattern data has been added. When a plurality of subfields having the pattern data are repeatedly arranged, the above-described steps (a) to (c) are performed on the first subfield of the subfield repeatedly arranged, and an auxiliary A charged particle beam exposure method, wherein when no exposure pattern is generated, the steps (a) to (c) are omitted except for at least a part of the remaining subfields. 9. The charged particle beam exposure method according to claim 8, wherein the steps (a) to (c) are performed for a boundary region between the subfields that are repeatedly arranged. 10. A charged particle beam exposure apparatus for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material according to the exposure data. Generating a plurality of areas in the subfield, determining a pattern density in the area, re-examining the pattern density in accordance with a pattern density of an area surrounding the area and a distance between the areas, and reviewing the area in the area. When the pattern density is lower than a predetermined exposure reference density, an auxiliary exposure pattern is generated in the area, and when the distance between pattern existing areas where the pattern is present is larger than a predetermined reference distance, the pattern existing area is generated. Area having a pattern density higher than the exposure reference density A) further generating an auxiliary exposure pattern, an exposure data generating unit for generating exposure data obtained by adding the auxiliary exposure pattern data to the pattern data, and irradiating the material with a charged particle beam according to the exposure data. A charged particle beam exposure apparatus, comprising: 11. A charged particle beam exposure apparatus for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material in accordance with the exposure data. Generating a plurality of areas in the subfield, determining a pattern density in the area, re-examining the pattern density in accordance with a pattern density of an area surrounding the area and a distance between the areas, and reviewing the area in the area. When the pattern density is lower than a predetermined exposure reference density, an auxiliary exposure pattern is generated in the area, the auxiliary exposure pattern has a desired exposure amount distribution according to a resist material on the material, An exposure for generating exposure data in which the auxiliary exposure pattern data is added to the pattern data. A charged particle beam exposure apparatus, comprising: an optical data generation unit; and an exposure unit that irradiates the material with a charged particle beam according to the exposure data to expose the material. 12. A charged particle beam exposure apparatus for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for a plurality of subfields in a main field, and exposing a material in accordance with the exposure data. In the above, a plurality of areas are generated around a predetermined range in a point symmetric manner from the center of the area where the pattern exists in the subfield, a pattern density in the area is obtained, and a pattern density of an area around the area is obtained. And reviewing the pattern density according to the distance between the areas, and when the reviewed pattern density of the area is lower than a predetermined exposure reference density, generating an auxiliary exposure pattern in the area, and applying the auxiliary exposure pattern to the pattern data. An exposure data generation unit for generating exposure data to which pattern data is added; Accordance exposure data, the charged particle beam exposure apparatus characterized by having an exposure unit for exposing and irradiating the charged particle beam to the article. 13. A charged particle beam exposure apparatus for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material in accordance with the exposure data. In, generating a plurality of areas in the sub-field, determine the pattern density in the area, review the pattern density according to the pattern density of the area around the area and the distance between the pattern existing area in the area, When the reviewed pattern density of the area is lower than a predetermined exposure reference density, an auxiliary exposure pattern is generated in the area,
An exposure data generation unit that generates exposure data obtained by adding the auxiliary exposure pattern data to the pattern data; and an exposure unit that irradiates the material with a charged particle beam according to the exposure data to perform exposure. Charged particle beam exposure equipment. 14. A charged particle beam exposure apparatus for obtaining exposure data having exposure pattern data for each subfield from pattern data having pattern data for each of a plurality of subfields in a main field, and exposing a material according to the exposure data. Generating a plurality of areas in the subfield, determining a pattern density in the area, re-examining the pattern density in accordance with a pattern density of an area surrounding the area and a distance between the areas, and reviewing the area in the area. An exposure data generating unit that generates an auxiliary exposure pattern in the area when the pattern density is lower than a predetermined exposure reference density and generates exposure data obtained by adding the auxiliary exposure pattern data to the pattern data; According to the data, the material is exposed to a charged particle beam and exposed. The exposure data generating unit, when a plurality of sub-fields having the same pattern data are repeatedly arranged, the auxiliary exposure to the first sub-field of the repeatedly arranged sub-field The charged particles are operated up to the generation of the pattern, and if no auxiliary exposure pattern is generated in the first subfield, the operation is omitted for at least the remaining subfields except for the boundary region. Beam exposure equipment.