JPH1131658A - Method and device for correcting proximity effect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate the effects of the rear scattering in a short time by calculating in advance a contribution exerted on a correction calculation by a typical pattern and blocking it by the area of the pattern and preparing a table for each block, in which the amount of effect is described at each position of the contour of the pattern and correcting the amount of irradiation at each position with reference to the table. SOLUTION: The amount of rear scattering exerted on each amount of irradiation by a typical pattern per a given area is calculated and is arranged according to the area of the typical pattern for making a table. When a typical pattern A is taken, if a table value is taken out based on the area and is applied to the mesh of the amount of irradiation with the center of the typical pattern A shaped like a mesh aligned with the center of the coordinates of the table value, the values Ua1 -Ua9 for the amounts of back scattering per a given area exerted on each mesh of the amount of irradiation by a typical pattern A are arranged. Similarly, the amounts of back scattering of the typical patterns A, B are arranged by taking out and summing the effects Ub1 -Ub7 of areas of the typical pattern B. The amounts of correction of irradiation per each irradiation mesh are calculated from the obtained amounts of back scattering to write the pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam writing technique, and more particularly, to a proximity effect correction method for reducing a proximity effect caused by the influence of backscattered electrons due to beam irradiation, and a proximity method for implementing the method. The present invention relates to an effect correction device.

[0002]

2. Description of the Related Art In an electron beam writing method, apparent exposure of a close figure increases due to reflected electrons (backscattered electrons and forward scattered electrons) from a substrate. Therefore, even with the same irradiation amount, the actual exposure amount differs between the dense pattern and the isolated pattern. This is called a proximity effect, and how to correct the pattern along with the miniaturization of the pattern is an important issue.

According to the irradiation amount D (X) incident on the place X,
Electron beam energy E (X ') is, E (X' in place ^{X') = (1 / πσf 2} ) exp {- (X-X ') 2 / σf 2} + (η / πσb 2) exp {- (XX ′) ² / σb ² … (1)

Here, .sigma.f is the spread of forward scattering, .sigma.b is the spread of backscatter, and .eta. Is the ratio of the total light amount of the resist due to the forward scattered electrons to that due to the backscattering. As one of the methods for reducing the proximity effect, there is a dose correction method in which the influence of the backscattering amount is calculated based on the size and density of the graphic pattern, and the dose is adjusted depending on the location.

[0005] Irradiation dose D (j) at location (Xj, Yj)
Is given by the backscattering effect U (j) from the center (Xi, Yi) of each figure to the location (Xj, Yj).
It is approximately obtained by the following equation.

D (j) = 1−kU (j) (k: constant, U: backscattering amount) (2) U (j) = {i [erf {(Xi−Xj + A) / σb} -erf {(Xi-Xj-B) / σb}] × [erf {(Yi-Yj + A) / σb} -erf {(Yi-Yj-B) / σb}] (3) where A and B are This shows each side when the graphic area is represented by a rectangular graphic.

As shown in the equation (2), the irradiation amount D is equal to the backscattering amount U.
Required by Since the calculation time is almost determined by the equation (3), the calculation method for calculating the backscatter in the equation (3) affects the calculation time required for the dose calculation.

A conventional example for calculating the influence U of the backscatter will be described with reference to FIGS. FIG.
Is an example of the case where the error function erf is converted into a subroutine in the above equation (3) and is calculated separately. As the drawing data, the area and position of the representative figure are input. Before calculating erf, first determine the lengths A and B of the sides from the figure area,
Next, the arguments of erf, Xi, Yi, Xj, Yj, A,
B and σb are passed to the function subroutine of erf, respectively.
The value of erf for each term is obtained by calculation, and the calculation of equation (3) is performed.

In this method, the calculation time is shortened by the parallel execution of the operation part of erf in equation (3) by another routine. However, erf is obtained by calculation each time, and it can be said that the erf is sufficiently reduced. Instead, it takes about 20 minutes (clock: 50 MIPS) to perform the correction calculation for the 1 cm ² area.

FIG. 13 is a graph showing the error function in equation (3).
This is an example in which erf is tabulated and a table value is used when calculating the backscattering amount U. In this case, the backscattering amount U
Is the same as that of FIG. 12, but the calculation of each term using Xi, Yi, Xj, Yj, A, B, and σb in parentheses as arguments is performed in advance, and the value of erf is stored in a table. Since it is prepared in advance, the time required to calculate erf in each operation is reduced.

U = Σ (dataα−dataβ) × (dataγ−dataδ) (4) In this method, the correction time for the 1 cm ² region is about 2
Minutes (clock: 50 MIPS).

When the above method is applied to reticle correction calculation, the area of the reticle is, for example, 200 cm.
^Since it is as large as ^2, it takes a lot of time for the correction calculation. That is, as shown in FIG. 12, in the calculation method in which the erf operation of the equation (3) is converted into a subroutine, the erf operation is required each time, so that the calculation of the irradiation dose requires about 7 days (clock: 50 MIPS). Need. In addition, as shown in FIG. 13, when only the calculation part of erf in the expression (3) is tabulated, the number of accesses in the calculation of erf is four times, which is smaller than the former, but about three days (clock: 50 MIPS) ) Calculation time is required.

That is, in the methods shown in FIGS. 12 and 13, the calculation time for calculating the influence U of the backscattering is as follows.
Although the speed is sufficient for direct drawing, it is still insufficient for reticle drawing, and further reduction in calculation time has been required.

[0014]

As described above, conventionally, in the dose correction for reducing the proximity effect, there is a method in which the error function erf is converted into a subroutine in order to calculate the influence of backscattering. Even with such a method, reticle drawing requires a great deal of calculation time, and a reduction in calculation time has been required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable calculation of the influence of backscattering in a short time in the irradiation dose correction for reducing the proximity effect. It is another object of the present invention to provide a proximity effect correction method and a proximity effect correction device which can sufficiently cope with reticle drawing.

[0016]

[Means for Solving the Problems]

(Structure) In order to solve the above problem, the present invention employs the following structure. That is, the present invention provides a proximity effect correction method for correcting the irradiation amount for each beam irradiation position in order to reduce the influence of the proximity effect due to beam irradiation when irradiating a charged beam on a sample to draw a desired pattern. In advance, the contribution of the figure or the representative figure to the proximity effect or the correction calculation is obtained, these are divided into blocks by the area of the figure used for the correction calculation, and the amount of the figure exerted at each position around the figure is described for each block. A table is prepared, and in the correction calculation, the contribution is obtained from the table from the positional relationship between the position where the irradiation amount is to be corrected and the figure adjacent thereto and the area of the figure, and based on the contribution, In this case, the irradiation amount is corrected for each position.

Also, the present invention provides a proximity effect correction for correcting an irradiation amount for each beam irradiation position in order to reduce the influence of the proximity effect due to the beam irradiation when irradiating a charged beam onto a sample to draw a desired pattern. In the method, the contribution of the figure or the representative figure to the proximity effect or the correction calculation is determined in advance, and these are divided into blocks based on the area of the figure used for the correction calculation and the center of gravity of the figure. A table describing the above-mentioned amount exerted by the figure is prepared, and in the correction calculation, the position relationship between the position where the irradiation amount is to be corrected and the figure adjacent thereto, the area of the figure, and the position of the center of gravity of the figure are calculated. The method is characterized in that the contribution amount is obtained from the table, and the irradiation amount is corrected for each position based on the contribution amount.

Further, according to the present invention, in a proximity effect correcting apparatus for realizing the above method, a table data memory storing backscattering amount data for each graphic area block, and an area and a center of gravity position based on graphic data and graphic position information. An arithmetic circuit for calculating a specified representative figure; means for obtaining the backscattering amount of the figure by referring to the table data memory from the area and the center of gravity of the representative figure obtained by the arithmetic circuit; The obtained backscattering amount is cumulatively added for each same address and stored, and the backscattering amount data memory for storing the backscattering amount data in the entire correction area, and the irradiation amount based on the contents of the backscattering amount data memory are stored. It is characterized by comprising an irradiation amount correction circuit for correcting.

(Operation) In the present invention configured as described above, the contribution of the figure or the representative figure to the proximity effect or the correction calculation is obtained, and the above-mentioned amount of the figure at each position around the figure is described for each block. By preparing a table and referring to this table for correction calculation,
In equation (3), the backscattering amount U of each position is obtained by accumulatively adding the backscattering amount U of the corresponding graphic area S as it is.

U (j) = {f (S)} = Σ (dataκ) (5) In this case, the calculation time required for 1 cm ² correction is 30 seconds or less (clock: 50 MIPS).

The contribution to the correction calculation is determined by the size of the figure and the positional relationship between the figure and the point to be corrected. For this reason, it is possible to divide the blocks by the area as described above.

As seen from the above equation (3), the irradiation amount D is determined by the backscattering amount U. It is known that the value of U is determined by the size (Aj, Bj) and position of the representative figure. In the present invention, the processing speed is improved by using the area instead of the size (Aj, Bj) of the representative figure. By using the area, the blocks are classified regardless of the shape of the representative figure. That is, as the area 4 [mu] m ² of the figure of the figure even 2 [mu] m × 2 [mu] m of 1 [mu] m × 4 [mu] m, can be handled in the same.

Therefore, according to the present invention, as shown in the above equation (5), the number of times the table is referred to is 1/4 of that in the case of FIG. 9, and the calculation amount is about 1 in the case of using the above equation (3). / 4 or less, area 2 in about 2.5 hours (clock: 50 MIPS)
A corrected irradiation amount of 00 cm ² can be obtained. This is a calculation speed that can sufficiently cope with reticle drawing.

According to the present invention, the center of the figure or the representative figure is always coincident with the center of gravity of the figure or the representative figure by dividing the figure or the representative figure into blocks in consideration of not only the area of the figure but also the position of the center of gravity of the figure. In addition, it is possible to perform accurate collation to further improve the correction accuracy.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. Here, an example applied to an electron beam writing apparatus will be described. (First Embodiment) FIG. 1 (a) shows an example of pattern data on a frame, FIG. 1 (b) shows a representative graphic example of each of the pattern data of FIG. 1 (a), and FIG. Indicates the range of influence of the influence on the surrounding irradiation mesh. FIG. 2 shows the area Sa of one representative figure.
FIG. 3 shows an example in which the distribution of the backscattering amount data with respect to the image is stored in a two-dimensional table, and FIG. Is shown.

First, a table is prepared in advance as follows. Assuming that each side B of the representative figure is B = A = S ^1/2 , the backscattering amount that the representative figure located at the center position (0, 0) exerts on the position (Xj, Yj) is: U (Xj, Yj) = [erf {-(Xj-A) / σb} -erf {-(Xj + B) / σb}] × [erf {-(Yj-A) / σb} -erf {-(Yj + B) / σb}]… Given by (6).

Therefore, the amount of backscatter exerted on each dose mesh by the representative figure per area is calculated, and as shown in FIG. 2, the above table values, that is, the backscatter amounts U1 to Un, are determined according to the area Sa of the representative figure. And arrange them. In the intensity distribution of the backscattering amount U, the center of each figure is set to the origin 0, and a small area of 2 μm × 2 μm, which is the same as the irradiation amount mesh, is arranged in units.

The size of the mesh for setting the representative figure (=
Σb = σ, which is an integral multiple of the irradiation mesh. Here, when the acceleration voltage is 50 kV, the corresponding σb = σ = 10 μm (FIG. 1).
(B)). At this time, since one side of the representative figure is a rectangle having a maximum of about 1σ, the maximum area of the representative figure is σ × σ = 10 μm × 10 μm = 100 μm ² .

The range of influence of backscattered electrons by irradiation at an acceleration voltage of 50 kV was set to a range of about 2.5σb from the center of the figure, that is, 5σb × 5σb. The table block of the representative graphic area S is Sa = 0.0 μm ^2-
At 100 μm ² , S = S at 0.1 μm ² pitch
Prepare 1000 pieces from 1 to S1000.

The correction is performed in the following procedure. An example of a calculation method using this table value will be described below. As shown in FIG. 1A, a representative figure, which is pattern data used for correction irradiation, is obtained from EB data of a desired pattern 1. As shown in FIG. 1B, the representative figure mesh 10
μm × 10 μm (rectangular area 2) is set, and the representative figure 4 used for the correction dose calculation is obtained. Each rectangle in FIG. 1B indicates the pattern arrangement of the representative figure 4. Here, when the pattern 1 is a rectangle and is arranged near the center of the rectangular area 2, the pattern 1 itself becomes a representative figure.

FIG. 1C shows a small area (irradiation mesh) 3 divided into 2 μm × 2 μm sections and a contribution range 5 based on the representative figure 4. Finally, the dose is set in this area.

FIGS. 3 (a) and 3 (b) show examples of the use range 5 and the table value of the backscattering amount for a representative figure 4 of a part of a certain frame. Figure A
Is described by Uai, and the amount of backscatter by figure B is described by Ubi.

Next, an example of a calculation method using this table will be described with reference to the flowchart of FIG. First,
A representative figure is selected, and its area S is obtained (T1). When a certain representative figure A is considered, it is assumed that this area is Sa. Therefore, the corresponding table value is extracted using the area Sa as an argument (T2), and the center (Xa
i, Yai) and the coordinate center (0, 0) of the table value are applied to the irradiation mesh, and the values of the backscattering amounts Ua1 to Ua9 that the representative figure A exerts on the surrounding irradiation meshes are arranged. (T3).

Similarly, the area S of another representative figure B
When the effects Ub1 to Ub7 of b are taken from the table values and cumulatively added (T4), the representative figures A and B
The amount of backscattering U (= Ua + Ub) due to the influence of is arranged. Further, by using the determination (T5) as to whether or not the selection of all the representative figures has been completed, by performing the above-described table reference, array of the backscattering amount, and cumulative addition for all the representative figures, each of the representative figures is 2 μm. The backscattering amounts U to be obtained are all arranged in each of the irradiation amount meshes of 2 μm.

Then, a calculation similar to the above equation (3) is performed by the above method. Further, according to the obtained backscattering amount U and the above equation (2) or D (j) = 1 / {1 + ηU (j)} (7), the corrected irradiation amount D (j) for each irradiation amount mesh is obtained. Desired. Therefore, by drawing a pattern with this corrected irradiation amount D (j), it is possible to perform drawing with proximity effect correction. When irradiation is performed at 50 kV, η is about 0.7 μm.

As described above, according to the present embodiment, the backscattering amounts U1 to Un corresponding to the figure area as shown in FIG. 2 are tabulated, and this table is referred to at the time of correction calculation for reducing the proximity effect. Thus, the backscattering amount U can be obtained, whereby the corrected irradiation amount can be obtained. In this case, in the calculation for obtaining the backscattering amount U, the table reference is limited to the number of the representative figures (1/4 in FIG. 9), and the calculation amount is also small (1 in equation (4)).
/ 4). Therefore, the influence of back scattering can be calculated in a short time, and it is possible to sufficiently cope with reticle drawing with a wide drawing area.

That is, since the contribution to the correction calculation is determined by the size of the figure and the positional relationship between the figure and the point to be corrected, the table value of the contribution can be divided into blocks by area. The "step of calculating the amount of backscattering", which requires the most calculation time, requires only one reference to the table for one correction point, so that high-speed arithmetic processing can be performed.
According to this, the calculation can be performed at four times or more the speed of the related art.

(Second Embodiment) In the first embodiment described above, the table shows the contribution of the figure or the representative figure to the proximity effect or correction calculation and the amount of backscattering, with the center of the representative figure as the center of gravity. The data is radially arranged, and is table data for each area block, and does not take into account the arrangement based on the position of the center of gravity. For this reason, when referring to the table, if the center of the figure or the representative figure does not match the center of gravity, it may deviate from the actual contributing arrangement, and accurate matching may not be obtained.

Therefore, in this embodiment, the figure or the representative figure is divided into blocks in consideration of the center of gravity of the figure instead of the area of the figure, so that the center of the figure or the representative figure always coincides with the center of gravity and the correction is performed. The accuracy has been further improved.

This embodiment will be described with reference to FIGS. 5 to 8 in addition to FIGS. FIGS. 5 to 8 show an example of storing a two-dimensional table in which the distribution of the backscattering amount data with respect to the area Sa of one representative figure is replaced. 5 and 6 show an even mesh type. FIG. 5 shows the even mesh and the center of gravity, and FIG. 6 shows the center of gravity and the backscattering amount distribution. 7 and 8 show an odd mesh type. FIG. 7 shows the odd mesh and the center of gravity, and FIG. 8 shows the center of gravity and the backscattering amount distribution.

First, a table is prepared in advance as follows. Assuming that each side B of the representative figure is B = A = Sa ^1/2 , the backscattering amount that the representative figure located at the center position (0, 0) exerts on the position (Xj, Yj) is: U (Xj, Yj) = [erf {-(Xj-A) / σb} -erf {-(Xj + B) / σb}] × [erf {-(Yj-A) / σb} -erf {-(Yj + B) / σb}]… Given by (6).

Then, the amount of backscattering exerted on each dose mesh by the representative figure per a certain area is calculated, and as shown in FIG. 2, the above table value, that is, the amount of backscattering U1 to Un is calculated according to the area Sa of the representative figure. And arrange them. The intensity distribution of the backscattering amount U is based on whether the representative figure mesh is odd multiple or even multiple of the irradiation mesh, and the table shape is divided into an odd type as shown in FIG. 7 and an even type as shown in FIG. 8,
As shown in FIG. 6, intensity distributions for nine positions of the center of gravity are arranged in consideration of nine positions of the center of gravity for one area.

At this time, this array is arranged in units of a small area of 1 μm × 1 μm which is the same as the irradiation mesh. The size of the mesh for setting the representative figure (= the maximum area of the representative figure) is σb = σ, which is an integral multiple of the irradiation amount mesh.

Here, when the acceleration voltage is 50 kV, the corresponding σb = σ = 10 μm (FIG. 1B). At this time, since one side of the representative figure is a rectangle having a maximum of about 1σ, the maximum area of the representative figure is σ × σ = 10 μm × 10 μm = 100 μm ² .

The range of influence of backscattered electrons by irradiation at an acceleration voltage of 50 kV was set to a range of about 2.5σb from the center of the figure, that is, 5σb × 5σb. The table block of the representative graphic area S is Sa = 0.0 μm ^2-
At 100 μm ² , at a pitch of 0.2 μm ² , S = S
Prepare 500 pieces from 1 to S500.

The correction proceeds in the following procedure. An example of a calculation method using this table value will be described below. As shown in FIG. 1A, a representative figure, which is pattern data used for correction irradiation, is obtained from EB data of a desired pattern 1. As shown in FIG. 1B, the representative figure mesh 10
μm × 10 μm (rectangular area 2) is set, and the representative figure 4 used for the correction dose calculation is obtained. Each rectangle in FIG. 1B indicates the pattern arrangement of the representative figure 4. FIG. 1 (c)
Indicates a small region (irradiation amount mesh) 3 divided into 1 μm × 1 μm sections and a contribution range 5 based on the representative figure 4. Finally, the dose is set in this area.

FIGS. 3 (a) and 3 (b) show examples of the use range 5 and the table value of the backscattering amount for a part of the representative figure 4 of a certain frame. Figure A
Is described by Uai, and the amount of backscatter by figure B is described by Ubi.

An example of using a table will be described with reference to FIG. When the representative figure A having the area Sa is considered, the table value corresponding to the area Sa, the table shape, and the center of the figure is extracted, and the center (Xai, Yai) of the representative figure A on the mesh is obtained.
When the coordinate center (0, 0) of the table value is applied to the dose mesh, the values of the backscattering amounts Ua1 to Ua6 which the representative figure A exerts on the respective dose meshes are arranged.

Similarly, with respect to the representative figure B having the area Sb, the influences Ub1 to Ub4 are taken out from the table values and cumulatively added.
The amount of backscattering U (= Ua + Ub) due to the influence of is arranged. By performing this for all the representative figures, all the backscattering amounts U to be obtained are arranged in each of the irradiation amount meshes of 1 μm × 1 μm.

Therefore, according to the above method, the same backscattering amount U (j) as that obtained by the calculation of the above equation (3) is given, and U (j) = {i [erf {(Xi-Xj + A) / σb} -erf {(Xi-Xj-B) / σb}] × [erf {(Yi-Yj + A) / σb} -erf {(Yi-Yj-B) / σb}]… (3) Correction for each dose mesh by the scattering amount U and (3) using the formula D (j) = 1−KU (j) (2) or D (j) = 1 / {1 + ηU (j)} (7) The dose D (j) is obtained. Therefore, by drawing a pattern with this corrected irradiation amount D (j), it is possible to perform drawing with proximity effect correction. When irradiation is performed at 50 kV, η is about 0.7 μm.

As described above, according to the present embodiment, the backscattering amounts U1 to Un corresponding to the figure area as shown in FIG. 2 are tabulated, and this table is referred to at the time of correction calculation for reducing the proximity effect. Thus, the backscattering amount U can be obtained, whereby the corrected irradiation amount can be obtained. In this case, in the calculation for obtaining the backscattering amount U, the table reference is only the number of representative figures, and the calculation amount is also small. Therefore, the influence of back scattering can be calculated in a short time, and it is possible to sufficiently cope with reticle drawing with a wide drawing area.

In this embodiment, the figure or the representative figure is divided into blocks in consideration of not only the area of the figure but also the center of gravity of the figure, so that the center of the figure or the representative figure always coincides with the center of gravity. it can. In addition, the arrangement is performed when the size of the representative figure mesh is not only an odd multiple of the irradiation dose mesh but also an even multiple. Therefore, the first
In the present embodiment, the table data, which allows accurate contribution arrangement only when the center of gravity of the representative figure and the center of the figure match, is used.In the present embodiment, the center of gravity of the representative figure matches the center of the figure. Even when there is no such arrangement, the calculation can be performed accurately for all the contributing arrangements, so that more accurate arithmetic processing can be performed. According to this, the error is less than 1%, and the calculation accuracy can be improved.

(Third Embodiment) In this embodiment, the present invention is realized by hardware, and this will be described with reference to FIGS.

FIG. 9 is an outline of a correction circuit of an electron beam writing apparatus. The graphic and its position data are sequentially input from the control computer 10 to the buffer memories 20 (21, 22), and the data in the buffer memory 20 is stored in the proximity effect correction circuit 3.
0 is input to the pattern data memory 40 (41, 42). The data corrected by the proximity effect correction circuit 30 is sequentially input to the dose data memory 50 (51, 52). Then, the data of the irradiation amount data memory 50 and the pattern data memory 40 are inputted to the control circuit 60.

FIG. 10 shows an example of the proximity effect correction circuit 30 shown in FIG. The figure and its position data sent from the buffer memory 20 to the data development circuit 31 are converted into area data by the data development circuit 31 and supplied to the representative figure creation circuit 32. In the representative figure creating circuit 32, area data of the rectangular representative figure and center-of-gravity position data of each representative figure are created, and the created data is supplied to the correction calculating circuit 33. In the correction calculation circuit 33, the same calculation as the above equation (3) is performed, and the optimum dose for each dose mesh is obtained and stored in the dose memory 50.

Here, FIG. 11 shows the table of the first embodiment applied to hardware. Representative figure creation circuit 7
At 0, area data and barycentric position data of the representative figure are calculated. Then, the address calculation circuit 71 calculates the address α of the figure area block.
Further, the address calculation circuit 72 calculates an arrangement position address β indicating where the representative figure exists on the irradiation amount mesh.

On the other hand, in the table data creation circuit 80,
With the representative figure mesh size as the maximum area, representative figure area data S up to 1/1000 and the amount of backscattering U (X, Y) associated with each area size are calculated at regular intervals, and these are stored in a table data storage memory. 81 respectively.

From the area address α calculated by the address calculation circuit 71, the corresponding backscattering amount Ua (X, Y) is sequentially calculated from the table data storage memory 81.
On the other hand, based on the arrangement position address β calculated by the address calculation circuit 72, each backscattering amount Uab (X ′, Y ′) of the corresponding area is sequentially extracted from the backscattering amount data storage memory 75.

Then, these Ua (X, Y) and Vab
(X ′, Y ′) are sequentially and cumulatively added by the cumulative addition circuit 76 for each corresponding mesh, and the values are stored at the corresponding mesh positions in the backscattering amount storage memory 75.

As described above, the table data creation circuit 80
Since the contribution data for each representative graphic area is summarized, the number of memory accesses from the circuit is smaller and the calculation time is reduced as compared with the conventional case where the contribution is calculated for each mesh address one by one. .

The present invention is not limited to the above embodiment. In the embodiment, the electron beam writing method has been described as an example. However, the present invention can be applied to any writing method in which the influence of backscattering due to beam irradiation poses a problem. For example, the present invention can be applied to an ion beam writing method. is there. Conditions such as the size of the irradiation amount mesh, the number of blocks of the representative figure area, the pitch, and the like can be appropriately changed according to the specifications. In addition, various modifications can be made without departing from the scope of the present invention.

[0062]

As described in detail above, according to the present invention, the contribution of a figure or a representative figure to the proximity effect or correction calculation is obtained, and the above-mentioned amount of the figure at each position around the figure is described for each block. By preparing a table and referring to this table in the correction calculation, the influence of the backscatter can be calculated in a short time in the irradiation dose correction for reducing the proximity effect, and the reticle drawing can be sufficiently coped with. .

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment, showing a pattern to be drawn, a representative graphic arrangement in a frame, and a graphic influence range in the frame.

FIG. 2 is a diagram illustrating an example of a backscattering amount table based on a graphic area;

FIG. 3 is a diagram showing an influence range of figures A and B in a frame and a backscattering amount of each dose mesh by the figures A and B;

FIG. 4 is a view showing a correction calculation method using a table according to the first embodiment;

FIG. 5 is a diagram showing a table used in the second embodiment (even meshes and positions of centroids).

FIG. 6 is a diagram showing a table used in the second embodiment (centroid position and backscattering amount distribution).

FIG. 7 is a diagram showing a table used in the second embodiment (an odd mesh and a position of a center of gravity).

FIG. 8 is a diagram showing a table used in the second embodiment (centroid position and backscattering amount distribution).

FIG. 9 is a block diagram illustrating a correction calculation unit of the electron beam writing apparatus according to the third embodiment.

FIG. 10 is a diagram showing a proximity effect correction circuit used in the correction calculation unit in FIG. 5;

FIG. 11 is a diagram showing an example of a correction calculation circuit using a table.

FIG. 12 is a diagram showing a conventional correction calculation method.

FIG. 13 is a diagram showing a conventional correction calculation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drawing pattern 2 ... Rectangular area 3 ... Drawing area (irradiation mesh) 4 ... Representative figure 5 ... Influence range of the representative figure 4 10 ... Control computer 20 ... Buffer memory 30 ... Proximity effect correction circuit 31 ... Data development circuit 32 ... Representative figure creation circuit 33 ... Correction calculation circuit 40 ... Pattern data memory 50 ... Control circuit 70 ... Representative figure creation circuit 71,72 ... Address calculation circuit 75 ... Backscattering amount data storage memory 76 ... Cumulative addition circuit 80 ... Table data creation Circuit 81: Table data storage memory T1: Representative graphic selection step T2: Subroutine T3: Representative graphic center T4: Array cumulative addition step T5: Representative graphic end determination step

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomohiro Iijima 1 Toshiba R & D Center, Komukai-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Susumu Oki Toshiba Komukai, Sai-ku, Kawasaki-shi, Kanagawa No. 1 Town Toshiba R & D Center (72) Inventor Takashi Kamikubo 1 Tokoba Toshiba Town, Koyuki Machi, Kawasaki City, Kanagawa Prefecture Toshiba R & D Center (72) Inventor Hiroto Yasue Kawasaki City, Kanagawa Prefecture No. 1, Komukai Toshiba-cho, Sachi-ku Inside Toshiba R & D Center

Claims (3)

[Claims] 1. A proximity effect correction method for correcting an irradiation amount for each beam irradiation position in order to reduce the influence of a proximity effect due to beam irradiation when irradiating a charged beam on a sample to draw a desired pattern. In advance, the contribution of the figure or the representative figure to the proximity effect or the correction calculation is obtained, these are divided into blocks by the area of the figure used for the correction calculation, and the amount of the figure exerted at each position around the figure is described for each block. A table is prepared, and in the correction calculation, the contribution is obtained from the table from the positional relationship between the position where the irradiation amount is to be corrected and the figure adjacent thereto and the area of the figure, and based on this contribution, A proximity effect correction method, wherein the irradiation amount is corrected for each position. 2. A proximity effect correction method for correcting an irradiation amount for each beam irradiation position in order to reduce the influence of a proximity effect due to beam irradiation when irradiating a charged beam on a sample to draw a desired pattern. The contribution of the figure or the representative figure to the proximity effect or the correction calculation is obtained in advance, and these are divided into blocks based on the area of the figure used for the correction calculation and the center of gravity of the figure. A table describing the above amount is prepared, and in the correction calculation, the positional relationship between the position where the irradiation amount is to be corrected and the figure adjacent thereto, the area of the figure, and the position of the center of gravity of the figure are used in the table. A proximity effect correction method, wherein the amount of contribution is obtained from the above, and the irradiation amount is corrected for each position based on the amount of contribution. 3. A proximity beam source for irradiating a charged beam onto a sample to draw a desired pattern, and for correcting an irradiation amount for each beam irradiation position in order to reduce the influence of a proximity effect due to beam irradiation. In the effect correction device, a table data memory storing backscattering amount data for each graphic area block, an arithmetic circuit for calculating a representative graphic defining an area and a center of gravity position from the graphic data and the graphic position information, and an arithmetic circuit obtained by the arithmetic circuit Means for obtaining the backscattering amount of the figure from the area and the center of gravity of the representative figure obtained by referring to the table data memory, and accumulating and storing the backscattering amount obtained by the means for each same address A backscattering amount data memory for storing backscattering amount data in the entire correction region, and irradiation is performed based on the contents of the backscattering amount data memory. A proximity effect correction device comprising a radiation amount correction circuit for correcting an amount.