JPH1126360A - Mask pattern creation method, mask pattern creation device, and mask creation device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To correct an exposure amount in accordance with a change in pattern area density due to a dimensional correction of a drawing pattern, thereby increasing an exposure dimensional margin and, at the same time, satisfying proximity effect correction. Provided are a mask pattern creation method, a mask pattern creation apparatus, and a mask creation apparatus that enable accurate pattern correction. SOLUTION: Dimension correction is performed on a drawing pattern based on design pattern data by an offset means 100 to change the pattern size (offset step). As a result, the exposure dimension allowance at the time of electron beam exposure is improved. Next, the proximity effect correction unit 200 performs the proximity effect correction on the drawing pattern whose size has been corrected according to the substantial change in the pattern area density accompanying the size correction (proximity effect correction step). After that, the drawing pattern corrected for the proximity effect by the drawing unit 300 is drawn on the mask substrate (drawing process).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mask pattern forming method and a mask pattern forming apparatus for forming a drawing pattern for electron beam exposure based on design pattern data in a lithography process of semiconductor manufacturing.

[0002]

2. Description of the Related Art In a lithography process of semiconductor manufacturing, when a semiconductor design pattern (drawing pattern) is drawn on a resist film formed on a substrate by electron beam exposure,
When an electron beam penetrates the resist film and enters the substrate, the electrons are largely scattered by the substrate, so-called backscattering may occur. In this case, a drawing pattern as designed cannot be formed. Therefore, there is widely known a method of predicting the scattering state of an electron beam, adding a dimensional correction (offset) to a design pattern according to the density and size of the drawing pattern, and changing the size of the drawing pattern to improve the exposure dimensional margin. Used.

FIG. 6 shows a relationship between an exposure amount and a pattern size when an isolated fine hole pattern which can sufficiently disregard a proximity effect is exposed by an electron beam using a positive resist. In the figure, curve 61 and curve 62
Means that the design size is Lμm □ (a square with Lμm on each side) and (L−ΔL) μm □ (each side is (L−ΔL) μm).
Square) are shown. The variation in pattern dimension (width) due to electron beam exposure follows a Gaussian distribution modeled by Chang et al.
It can be seen that as the exposure amount increases, the differential coefficient, that is, the pattern dimension variation amount with respect to the change in the exposure amount decreases. The optimum exposure amount at which the pattern size becomes L μm in the curve 61 is D ₁ (μC / cm ² ), and the optimum exposure amount at which the pattern size becomes L μm is D ₃ (μC / cm
² ), the derivative at (D ₁ , L) is larger than the derivative at (D ₃ , L). As can be seen from this, when exposing a pattern having a design size of L μm □, exposure is performed with the pattern size reduced by ΔL μm (L−ΔL) μm □ and the exposure amount is made larger than the optimum exposure amount. The smaller the deviation from the design size, the better the exposure dimensional margin (exposure margin).

However, when the patterns to be drawn are close to each other, a proximity effect, which is a particularly remarkable phenomenon in electron beam exposure, occurs.
The effect of backscattering due to electrons re-entering from the substrate is large, and the amount of exposure increases as compared with an isolated semiconductor pattern. In particular, in recent years, LSI (Large Scale Integrated cir
cuit) With the miniaturization of patterns, the acceleration voltage of electron beams has been increased to 50 kV instead of the conventional 20 to 30 kV. In writing using a high acceleration voltage, the range of backscattering is large, and the backscattering radius is 10 μm or more. Therefore, when drawing design data in which the density of drawing patterns is variously mixed, such as a peripheral circuit of a logic device or a memory device, by electron beam exposure,
It is essential to perform the proximity effect correction, and it is widely performed in general. When the backscattering radius is 10 μm or less,
Since the stored energy due to the backscattering is made uniform based on the pattern area density of the drawing pattern in the unit section without depending on the figure pattern, it can be expressed as the following equation (2). The pattern area density is α, the reflection coefficient from the substrate to the resist is η, and the accumulated energy due to backscattering when the exposure amount is D is E _back . Reflection coefficient η
Is a unique value determined by the type of the accelerating voltage, the resist film, and the substrate serving as the base.

[0005]

(Equation 2)

Therefore, the proximity effect correction can be performed by changing the exposure amount according to the pattern area density. Now, assuming that the appropriate exposure amount at a pattern area density of 50% (α = 0.5) is D ₅₀ , the correction exposure amount D _cor can be expressed by the following equation (3), and the proximity effect correction can be performed. .

[0007]

(Equation 3)

FIG. 7 shows a case where a drawing pattern having a design size of L μm □ and an area density of α ₁ , α ₂ , α _{3 in} the order of α ₁ , α ₂ , and α ₃ , which is dense enough to cause a proximity effect, is exposed by an electron beam.
It shows the relationship between the exposure amount and the pattern size. In the figure, a curve 71 shows the characteristic when the pattern area density is α ₁ , a curve 72 shows the characteristic when the pattern area density is α ₂ , and a curve 73 shows the characteristic when the pattern area density is α ₃ (α ₁ <α ₂ <α ₃ ). I have. Here, since the exposure amount is changed in accordance with the pattern area density by performing the proximity effect correction, the same exposure amount D (μC / cm
^{In 2} ), a drawing pattern according to the design size can be obtained.

[0009]

However, when the drawing pattern size is changed in order to improve the exposure dimensional margin as described above, the pattern area density itself changes and the value of the corrected exposure amount also changes. In particular, when the drawing pattern size is reduced, the appropriate exposure amount also changes, so that the correction exposure amount greatly changes. Therefore, when the drawing pattern size is changed, there is a problem that the conventional proximity effect correction method using the pattern area density cannot be directly applied.

For example, FIG. 8 shows the relationship between the amount of exposure and the pattern size when the semiconductor pattern similar to that shown in FIG. 7 is exposed after correcting it to a semiconductor pattern size ((L−ΔL) μm □) smaller by ΔL μm. Is represented. In the figure, a curve 81 indicates a pattern area density α ₁ , and a curve 8
2 indicates the characteristic when the pattern area density is α ₂ , and the curve 83 indicates the characteristic when the pattern area density is α ₃ (α ₁ <α ₂ <α ₃ ). In this case, if the correction of the electron beam size is performed without considering the fluctuation of the pattern area density, the actual pattern area density becomes smaller than the pattern area density on the design pattern. Run short. Further, since the drawing pattern size also varies depending on the pattern area density, the proximity effect correction does not function. Therefore, in this figure, the exposure energy intensity at which the pattern dimension becomes L μm differs for each curve.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to correct an exposure amount in accordance with a change in pattern area density due to a dimensional correction of a drawing pattern, thereby reducing an exposure dimensional margin. It is an object of the present invention to provide a method of creating a mask pattern that can be enlarged and satisfy proximity effect correction at the same time, and that enables highly accurate pattern correction.

A second object of the present invention is to provide a mask pattern forming apparatus capable of performing highly accurate pattern correction by applying the mask pattern forming method of the present invention.

[0013] A third object of the present invention is to provide a mask pattern forming apparatus according to the present invention, whereby a drawing pattern based on design pattern data can be drawn on a mask substrate, thereby improving the manufacturing yield. It is to provide a device.

[0014]

According to the present invention, there is provided a method of forming a mask pattern, comprising the steps of: performing a dimension correction of a drawing pattern based on design pattern data to improve an exposure dimension margin; And a proximity effect correction step of performing a proximity effect correction on the drawing pattern whose size has been corrected in accordance with the substantial change in the pattern area density.

The mask pattern forming apparatus according to the present invention comprises:
Offset means for improving the exposure dimension margin by performing dimension correction of the drawing pattern based on the design pattern data, and to a drawing pattern whose size has been corrected in accordance with a substantial change in pattern area density accompanying the size correction of the drawing pattern. And a proximity effect correcting means for performing the proximity effect correction.

According to the present invention, there is provided a mask forming apparatus, comprising: offset means for improving a dimension tolerance of an exposure by performing dimension correction of a drawing pattern based on design pattern data;
Proximity effect correction means for performing a proximity effect correction on the dimensionally corrected drawing pattern in accordance with a substantial change in pattern area density accompanying the dimension correction of the drawing pattern, and masking the drawing pattern corrected by the proximity effect correction means Drawing means for drawing on a substrate.

In the mask pattern forming method and the mask forming apparatus according to the present invention, the dimensional tolerance of the drawing pattern is improved based on the design pattern data, so that the exposure dimensional margin is improved, and the substantial size accompanying the dimensional correction of the drawing pattern is improved. Proximity effect correction is performed on the drawing pattern whose size has been corrected according to the change in the pattern area density.

In the mask forming apparatus according to the present invention, the drawing pattern subjected to the dimension correction and the proximity effect correction is drawn on the mask substrate by the mask pattern forming apparatus according to the present invention.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a conceptual configuration of a mask making apparatus (electron beam exposure machine) according to an embodiment of the present invention. This mask producing apparatus is an application of the mask pattern producing method and the mask pattern producing apparatus of the present invention. The mask creating apparatus 1 includes: an offset unit 100 that performs dimension correction of a drawing pattern based on design pattern data to improve an exposure dimension allowance; and a mask unit that responds to a change in a substantial pattern area density accompanying the dimension correction of the drawing pattern. A proximity effect correction unit 200 for performing a proximity effect correction on a drawing pattern whose dimensions have been corrected by the method, and a drawing unit 300 for drawing the drawing pattern corrected by the proximity effect correction unit 200 on a mask substrate. doing. Of the above, the offset means 100 and the proximity effect correction means 200 constitute the mask pattern forming apparatus 2 of the present invention, and the offset means 100 and the proximity effect correction means 200 operate on a computer (electronic) based on a predetermined program. (Computer) or the like. This program may be supplied in advance in a device such as a computer, or may be supplied from outside via various recording media or communication means.

Next, the operation of the mask making apparatus 1 will be described in detail with reference to FIGS. In the mask making apparatus 1, as shown in the flowchart of FIG. 2, the offset unit 100 performs dimension correction (minus offset) of the drawing pattern based on the design pattern data to change the pattern size (step S100; Offset process). As a result, the exposure dimension allowance at the time of electron beam exposure is improved. Next, the proximity effect correction unit 200 performs proximity effect correction on the dimensionally corrected drawing pattern in accordance with a substantial change in the pattern area density accompanying the dimension correction of the drawing pattern (step S200; proximity effect correction step). After that, the drawing pattern corrected for the proximity effect by the drawing unit 300 is drawn on the mask substrate (step S300; drawing step).

[Proximity Effect Correction by Area Density Map Method]
FIG. 3 is a flowchart for explaining the procedure of the proximity effect correction by the area density map method applied to the mask producing apparatus 1. In this area density map method, first, (A) the drawing pattern whose dimensions have been corrected in the offset step is divided into predetermined unit sections (mesh), and each unit section is developed into a bit map of a certain grid size (step S20).
1). (B) Next, using this bitmap, the pattern area density (α ′) per unit section of the dimensionally corrected drawing pattern is calculated (step S202). The pattern area density (α ′) can be determined by the product of the pattern area density (α) of the drawing pattern of the design size and the rate of change of the pattern area density due to dimensional correction, as described later. The pattern area density (α) can also be easily obtained by developing a drawing pattern of the design size into a bitmap in the same manner as described above. (C) Next, based on the pattern area density (α ′), the correction exposure amount D ′ _cor in each unit section is calculated (Step S).
203). This correction exposure amount D _cor can be obtained from the following equation (14). Thereafter, a corrected exposure amount table is created by allocating the corrected exposure amount D ' _cor of each exposure shot (rectangular shape) to each unit section (step S20).
4).

It is desirable to perform an averaging process (smoothing process, smoothing process) on the calculated pattern area density (α ′). In this averaging process, the operation of simply averaging the pattern area density in a unit block in the vicinity of the unit block of interest is performed a plurality of times, or the region about three times the backscattering radius is subjected to backscattering for the unit block of interest. This can be done by obtaining a weighted average based on the magnitude of the effect. By performing the averaging process, the mutual proximity effect due to the backscatter over a wide range can be reflected in the correction of the exposure amount. The calculation of the pattern area density, the averaging process, and the calculation of the corrected exposure amount D ′ _cor are all arithmetic calculations, and can be performed in a very short time by a computer.

[0024] [corrected exposure dose D _cor calculation procedure of Hereinafter, calculation procedure of the corrected exposure dose D _'cor of the present embodiment will be specifically described. In this embodiment, in order to improve the exposure margin, a square drawing pattern having a design size of L μm □ is subjected to dimension correction (negative offset) by ΔL μm, for example, and the pattern size is reduced to draw ( Proximity effect correction for (L-ΔL) μm □) is performed. Here, FIG. 4A is an exposure energy intensity distribution when a square drawing pattern having a design size of L μm □ is exposed, and FIG. 4B is a drawing of a square of (L−ΔL) μm □. The intensity distribution of exposure energy when the pattern is exposed is shown. Note that the accumulated energy intensity due to forward scattering and back scattering can be approximated by a Gaussian distribution, and a threshold (threshold level) is set to a half of the accumulated energy intensity distribution. It is assumed that a drawing pattern is formed and no drawing pattern is formed in a lower portion.

(A) First, dimensional correction is performed by ΔL μm on a drawing pattern having a design size of L μm square, and (L−
ΔL) The accumulated energy (E ′ _back ) due to backscattering when drawing with a pattern size of μm □ is obtained. The rate of change of the pattern area density due to the dimensional correction of the drawing pattern is ((L−ΔL) / L) ² . Therefore, the pattern area density (α ′) after the dimension correction is represented by the product of the change rate of the pattern area density and the designed pattern area rate (α) as shown in the following equation (4). By substituting the pattern area density (α ′) after the dimension correction into the pattern area density (α) of the equation (2), the stored energy (E) when the dimension correction is performed as shown in the following equation (5) '
_back ) is obtained.

[0026]

(Equation 4)

[0027]

(Equation 5)

Here, the slice level when the dimension is corrected by ΔL μm is I ′ _th , and the reflection coefficient from the substrate to the resist is η. The slice level is a ratio to the electron beam intensity due to forward scattering, and a value obtained by multiplying the electron beam intensity by the slice level is a threshold (threshold level). The slice level for the electron beam intensity due to forward scattering that gives the design size is I _th (0 <I _th <
_Assuming that 1), this I _th is 0.5 when performing drawing according to the design size, and the value of the slice level I ′ _th when performing dimensional correction is as shown in FIG. Is smaller than 0.5.

(B) Next, the optimum exposure amount for drawing a dimensionally corrected drawing pattern (L-ΔL) μm □ in an isolated system that is so sparse as to allow the proximity effect to be sufficiently ignored is D ′ _iso-op
Then, the pattern edge exposure energy intensity E ' _edge-iso at this time is obtained by the following equation (6).

[0030]

(Equation 6)

The optimum exposure amount when writing a drawing pattern of the design size with a reference pattern area density of, for example, 50% (α = 0.5) is D _{50 -op.}
Then, the pattern edge exposure energy intensity E ′ _edge-iso when the dimension correction of the drawing pattern is performed is expressed by the following equation (7).

[0032]

(Equation 7)

(C) Next, the pattern edge exposure energy intensity E ' _edge is calculated when the dimensionally corrected drawing pattern ((L-ΔL) μm □) is drawn in a dense system in which the proximity effect cannot be ignored. . The pattern edge exposure energy intensity E ′ _edge is equal to the accumulated energy E ′ _forward due to forward scattering and the dimensionally corrected drawing pattern ((L−Δ
L) The product of μm □) and the slice level I ′ _th, and (a)
Energy E ' _back due to backscattering obtained in the procedure of
And the following equation (8).

[0034]

(Equation 8)

The stored energy intensity E 'due to forward scattering
_{The forward} is represented by the following equation (9) using the reflection coefficient η and the correction exposure amount using D ′ _cor .

[0036]

(Equation 9)

The accumulated energy E ′ _back due to the back scattering of the dimensionally corrected drawing pattern is _calculated by the following equation (10) using the pattern area density α ′ of the dimensionally corrected drawing pattern and the corrected exposure amount D ′ _cor. expressed.

[0038]

(Equation 10)

From the equations (9) and (10), the pattern edge exposure energy intensity E ′ _edge when the dimension of the drawing pattern is corrected in a system where the proximity effect cannot be ignored is given by the following equation (1).
It can be represented by 1).

[0040]

[Equation 11]

(D) Next, the pattern edge exposure energy intensity E ′ _edge obtained in the procedure (c) is used to draw an isolated pattern of the design size obtained in the procedure (b) at a pattern area density of 50%. By setting the correction exposure amount D ′ _cor to be equal to the pattern edge exposure energy intensity E ′ _edge-iso (that is, one half of the optimum exposure amount D _{50 -op} ) (see Equation 7) when performing the correction. In addition, it is possible to correct the proximity effect when the pattern area density is changed by correcting the dimension of the drawing pattern. Therefore, the right side of the above equation (11) is set to one half of the optimum exposure amount D _{50-op and} the correction exposure amount is set to D ′ _cor
Is solved, the following equation (12) is obtained.

[0042]

(Equation 12)

Here, since the following expression (13) is established from the expressions (6) and (7), the expression (12) can be transformed into the expression (14).

(Equation 13)

[0044]

[Equation 14]

It should be noted that the optimum exposure amount D in the isolated pattern
Optimal exposure D 'for _50-op and size correction
_{The iso-op and the} reflection coefficient η can be easily determined experimentally by performing a drawing experiment in advance. Further, in a complete line and space pattern, the pattern size is corrected one-dimensionally, so that the correction formula is given by the following formula (15), and correction can be similarly performed.

(Equation 15)

As described above, in the present embodiment, the dimensional correction is performed on the drawing pattern based on the design pattern data and the pattern size is changed, so that the exposure dimensional margin is improved and the correction for performing the proximity effect correction is performed. The change in the pattern area density is reflected in the equation. Therefore, appropriate proximity effect correction can be performed only by changing the pattern dimensions at the time of drawing the drawing pattern without changing the design size data. That is, the proximity effect correction to the dimensionally-corrected drawing pattern is performed in accordance with a substantial change in the pattern area density accompanying the dimension correction of the pattern to be drawn, and the dimensional correction improves the exposure dimensional margin and improves the proximity effect with high accuracy. Correction can be realized simultaneously. Therefore, by drawing the pattern on which the proximity effect correction has been performed on the mask substrate, the same mask as the design pattern can be created.

FIG. 5 shows the case where the proximity effect correction is performed in this manner, and then a pattern having a pattern size (L-ΔL) μm □ is drawn by exposing with a correction exposure amount D ′ _cor (μC / cm ² ). The relationship between the exposure energy and the drawn line width is shown. In the figure, a curve 51 represents a pattern area density α ₁ , a curve 52 represents a pattern area density α ₂ , and a curve 53.
Indicates the characteristics when the pattern area density is α ₃ (α ₁ > α ₂ > α ₃ ). All curves have line width L
The correction exposure amount that becomes μm is D ' _cor , and the exposure amount is corrected according to the change in pattern area density due to the dimensional correction of the drawing pattern, so that the exposure dimensional margin can be expanded and the proximity effect correction must be satisfied. And high-precision pattern correction becomes possible.

[0048]

As described above, according to the method of forming a mask pattern according to the present invention, the dimensional correction of the drawing pattern based on the design pattern data is performed, and the substantial pattern area density accompanying the dimensional correction of the drawing pattern is obtained. Since the proximity effect correction is performed on the drawing pattern whose size has been corrected in accordance with the change in the image size, there is an effect that the exposure dimension allowance is improved and at the same time appropriate proximity effect correction becomes possible.

Further, according to the mask pattern forming apparatus of the present invention, since the method of forming a mask pattern of the present invention is applied, it is possible to improve the exposure dimensional margin and at the same time to perform appropriate proximity effect correction. , And highly accurate pattern correction becomes possible.

Further, according to the mask making apparatus of the present invention,
The provision of the mask pattern forming apparatus of the present invention enables a high-precision drawing pattern based on the design pattern data to be drawn on the mask substrate, thereby improving the manufacturing yield, and thus, direct drawing using an electron beam. This makes it possible to produce practical VLSI prototypes.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a mask creating apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the mask making apparatus of FIG. 1;

FIG. 3 is a flowchart illustrating a proximity effect correction method using a pattern area density applied to the mask creating apparatus of FIG. 1;

FIG. 4A shows a case where a square drawing pattern having a design size of L μm □ is exposed, and FIG. 4B shows a drawing pattern of a square having a size of (L−ΔL) μm in which the design size is corrected. FIG. 4 is a diagram illustrating respective intensity distributions of exposure energy when exposure is performed on.

FIG. 5 is a diagram for explaining exposure-pattern width fluctuation when proximity effect correction using a pattern area density is performed by a mask pattern creation method according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining the exposure amount-pattern width variation in the case where exposure is performed on a drawing pattern having a design size of L μm □ and a drawing pattern of (L−ΔL) μm in which dimension correction has been performed on the design size. FIG.

FIG. 7 is a diagram for explaining exposure-pattern width fluctuation when proximity effect correction is performed on a drawing pattern having a design size of L μm □.

FIG. 8 is a diagram for explaining a variation in exposure amount-pattern width when proximity effect correction is performed on a (L-ΔL) μm □ drawing pattern whose dimension has been corrected by a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mask producing device, 2 ... Mask pattern producing device, 1
00: offset means, 200: proximity effect correction means, 3
00 ... drawing means

Claims (6)

[Claims] In a mask pattern creating method for creating a drawing pattern for electron beam exposure based on design pattern data, an offset for improving a dimension margin of exposure by performing dimension correction of the drawing pattern based on the design pattern data. And a proximity effect correction step of performing a proximity effect correction step of performing a proximity effect correction to the dimension-corrected drawing pattern in accordance with a substantial change in pattern area density accompanying the dimension correction of the drawing pattern. How to make. 2. The proximity effect correction step includes: (A) a step of dividing the drawing pattern subjected to the dimension correction in the offset step into predetermined unit sections; and (B) a bit map development of each of the divided unit sections. Calculating a pattern area density per unit section of the drawing pattern whose size has been corrected using the bitmap; and (C) calculating a corrected exposure amount for each exposure shot based on the calculated pattern area density. 2. The method according to claim 1, further comprising the steps of: 3. The pattern area density of the drawing pattern of the design size is α, the reflection coefficient from the mask substrate to the resist is η, the design size of the drawing pattern is L, the dimension correction amount (offset amount) is ΔL, and the drawing of the design size is performed. 50% pattern
_D50-op is the optimal exposure dose when writing with a pattern area density of, and the optimal exposure dose when writing a dimensional-corrected writing pattern in a sparse isolated system that can sufficiently ignore the proximity effect. D ′ _iso-op , the corrected exposure amount D ′
_{Let cor} be the following equation: 3. The method according to claim 2, wherein the mask pattern is obtained by: 4. The step of calculating an exposure correction amount in the proximity effect correction step includes the steps of: (a) performing dimensional correction on a drawing pattern based on design pattern data; The pattern area density of the dimensionally corrected drawing pattern is calculated by multiplying the pattern area density of the pattern by the pattern area density based on the pattern data. (B) when the dimensional correction is performed using the optimum exposure amount in the case where the dimensional corrected drawing pattern is drawn in an isolated system that is sparse enough to ignore the proximity effect sufficiently While calculating the pattern edge exposure energy intensity, the pattern edge exposure energy intensity (C) a procedure expressed by using an optimum exposure amount when writing is performed at a pattern area density of 0%; (c) a stored energy due to back scattering obtained in the procedure of (a), and a forward scattering due to electron beam exposure. A procedure for calculating the pattern edge exposure energy intensity when the dimensional correction of the drawing pattern is performed from the sum of the stored energy, and a procedure for calculating the pattern edge exposure energy intensity obtained in the procedures (d) and (c). Is set to be equal to the pattern edge exposure energy intensity obtained in the above, and the corrected exposure amount in consideration of the change in the pattern area density due to the dimensional correction is calculated using the two types of optimal exposure amounts obtained in the procedure of (b). 3. The method according to claim 2, wherein the method is performed by the following procedure. 5. A mask pattern creating apparatus for creating a drawing pattern for electron beam exposure based on design pattern data, wherein the dimension of the drawing pattern is corrected based on the design pattern data to improve an exposure dimension margin. A mask pattern comprising: an offset unit; and a proximity effect correction unit that performs a proximity effect correction on a drawing pattern whose size has been corrected according to a substantial change in pattern area density accompanying the size correction of the drawing pattern. Creating device. 6. A mask creating apparatus for creating a mask in which a drawing pattern based on design pattern data is drawn on a mask substrate, wherein a dimension of the drawing pattern is corrected based on the design pattern data to thereby provide an exposure dimension margin. Offset means for improving the degree of proximity, proximity effect correction means for performing a proximity effect correction on a drawing pattern whose size has been corrected in accordance with a substantial change in pattern area density accompanying the size correction of the drawing pattern, and this proximity effect correction means And a drawing means for drawing a drawing pattern corrected by the method on a mask substrate.