JP5350523B2 - Charged particle beam drawing apparatus and charged particle beam drawing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing apparatus and method in which a global position error is corrected highly accurately. <P>SOLUTION: A drawing apparatus 100 comprises an electron gun 201 which radiates electron beams 200, an XY stage 105 on which a sample 101 is placed, a main deflection arithmetic unit 114 which corrects a reference position of an SF within a drawing area of the sample 101 to be a drawing target on the basis of pattern distortion obtained from positions of a plurality of graphics which are distributed over all the surface of the drawing area of a dummy sample and are drawn without being corrected, a main deflector 214 which deflects the electron beams 200 on the basis of a corrected reference position, a sub deflection arithmetic unit 112 which corrects a relative distance from the corrected reference position to any arbitrary position within a small area using a coefficient of a correction expression for correcting the reference position on the basis of the pattern distortion of the dummy sample and using the reference position, and a sub deflector 212 which further deflects the electron beams 200 from the position deflected by the main deflector 214 on the basis of the corrected relative distance. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a charged particle beam drawing apparatus and a charged particle beam drawing method, and for example, relates to a drawing apparatus and method for correcting distortion generated in a subfield (SF).

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

FIG. 6 is a conceptual diagram for explaining the operation of the variable shaped electron beam drawing apparatus.
The variable shaped electron beam (EB) drawing apparatus operates as follows. First, the first aperture 410 is formed with a rectangular opening 411 for forming the electron beam 330. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 442 that has passed through the opening 411 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 is deflected by a deflector. And it passes through a part of variable shaping | molding opening 421, and is irradiated to the sample mounted on the stage. The stage continuously moves in a predetermined direction (for example, the X direction) during drawing. Thus, a rectangular shape that can pass through both the opening 411 and the variable shaping opening 421 is drawn in the drawing region of the sample 340. A method of creating an arbitrary shape by passing both the opening 411 and the variable forming opening 421 is referred to as a variable forming method.

Here, in the electron beam drawing apparatus, there are several factors that degrade the position accuracy of the pattern. For example, there is a deterioration in position accuracy generated in the electron optical system, a tilt or distortion of a mirror set on the stage for measuring the stage position, or a deflection of a mask serving as a sample. In particular, the tilt and distortion of the mirror or the deflection of the mask changes gently over the entire mask. Therefore, a gentle position error (global position error) occurs over the entire mask due to these distortions or deflections. Here, in the electron beam drawing apparatus, the drawing area is divided into small areas (SF: subfield), and drawing is performed for each SF. Conventionally, it has been attempted to correct the global position error as described above by correcting the SF reference position described above when drawing (see, for example, Patent Document 1).
Further, when a mask pattern is transferred onto a silicon wafer using a mask produced by an electron beam lithography apparatus and an exposure apparatus, distortion occurs when the mask is set in the exposure apparatus. For example, an exposure / transfer apparatus using EUV (Extreme UltraViolet) light has recently been studied. The mask is fixed by an electrostatic chuck inside the exposure / transfer apparatus, but distortion occurs in the mask. This distortion needs to be corrected in advance on the mask. Hereinafter, the distortion generated in the exposure / transfer apparatus is also referred to as “distortion”, and the distortion correction in this case is also referred to as “distortion correction”.

FIG. 7 is a conceptual diagram for explaining conventional distortion correction.
As shown in FIG. 7A, when the drawing area 20 is distorted or bent, the position of the center 24 of the SF 22 is positioned on a straight line as shown in FIG. 7B after drawing. The position of the center 24 was corrected. FIG. 7A shows an example of the positional relationship after correction. That is, here, only the coordinates of the center 24 of each SF 22 are corrected without correcting the distortion of the SF 22 itself. Here, some SF22a-22e and its center 24a-24e are shown. However, in this method, the same correction is applied to all shot positions inside the SF 22. Therefore, after drawing, there is a problem that an error due to distortion or deflection inside the SF remains as shown in FIG. Therefore, correction with sufficient accuracy could not be performed.

Japanese Patent No. 3197024

  With the recent miniaturization of patterns, it is desired to correct errors due to distortion or deflection in the SF with high accuracy, and it is not sufficient as correction accuracy only to correct the SF position as described above. There was a problem that it was becoming.

  Therefore, an object of the present invention is to provide a drawing apparatus and method for overcoming such problems and correcting a global position error with high accuracy.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
An irradiation unit for irradiating a charged particle beam;
A stage on which a sample to be drawn is placed;
The reference position of the small area in the drawing area of the sample to be drawn is corrected based on the pattern distortion obtained from the positions of a plurality of figures drawn without correction scattered over almost the entire drawing area of the dummy sample. A first correction unit;
A first deflector for deflecting the charged particle beam based on the corrected reference position with the corrected reference position;
A second correction unit that corrects a relative distance from the correction reference position to an arbitrary position in the small region using a coefficient of the correction formula for correcting the reference position based on the pattern distortion of the dummy sample and the reference position; ,
A second deflector for further deflecting the charged particle beam from the position deflected by the first deflector based on the corrected relative distance;
It is provided with.

  By correcting the relative distance from the correction reference position to an arbitrary position within the small area using the coefficient of the correction formula for correcting the reference position based on the pattern distortion of the dummy sample and the reference position, It is possible to draw at a position where not only the reference position but also the global position error in the small area is eliminated or reduced.

  The charged particle beam drawing apparatus is further arranged on the stage with a length longer than the drawing area along the drawing area of the sample. The mirror reflects the laser light, and the laser beam is irradiated and reflected from the mirror. A measurement unit that receives the laser beam and measures the position of the stage based on the received laser beam.

  Further, it is preferable that the second correction unit further corrects an error in the relative distance caused by the charged particle beam optical system.

  The second correction unit includes a correction equation coefficient for correcting the relative distance error caused by the optical system of the charged particle beam and the coefficient of the correction equation for correcting the relative distance based on the pattern distortion of the dummy sample. It is preferable to correct the relative distance using a coefficient obtained by combining the coefficients.

The charged particle beam drawing method of one embodiment of the present invention includes:
In a charged particle beam writing method for drawing a predetermined pattern on a sample by deflecting a charged particle beam using a main and sub two-stage deflector,
A main deflector in a small area within the drawing area of the sample to be drawn on the basis of pattern distortion obtained from the positions of a plurality of figures drawn without correction scattered over almost the entire drawing area of the dummy sample. Correcting the deflection reference position;
Using the coefficient of the correction formula for correcting the reference position based on the pattern distortion of the dummy sample and the reference position, from the corrected reference position where the reference position is corrected to an arbitrary position within the small region Correcting the relative distance deflected by the sub-deflector;
A charged particle beam drawing method comprising:

  According to the present invention, a global error at an arbitrary position in a small area can be eliminated or reduced. Therefore, a global position error can be corrected with high accuracy. As a result, it is possible to draw at a more accurate position.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. FIG. 4 is a flowchart showing main steps of the drawing method according to Embodiment 1. FIG. 3 is a conceptual diagram for explaining a method for measuring a global positional shift amount using a dummy substrate in the first embodiment. 6 is a diagram showing an example of a global position error in the first embodiment. FIG. 6 is a conceptual diagram for explaining SF correction for a global position error in Embodiment 1. FIG. It is a conceptual diagram for demonstrating operation | movement of a variable shaping type | mold electron beam drawing apparatus. It is a conceptual diagram for demonstrating the conventional distortion correction.

Embodiment 1 FIG.
Hereinafter, in the embodiment, a configuration for performing distortion correction at an arbitrary position in the SF will be described. In the embodiment described below, a configuration using an electron beam as an example of a charged particle beam will be described. However, the charged particle beam is not limited to an electron beam, and may be a beam using other charged particles such as an ion beam.

  FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing unit 150 and a control unit 160. The drawing apparatus 100 is an example of a charged particle beam drawing apparatus. The drawing apparatus 100 draws a desired pattern on the sample 101. The control unit 160 includes a drawing control circuit 120, a laser measurement system 130, a magnetic disk device 109, a deflection control circuit 110, digital / analog converters (DACs) 122 and 124, and amplifiers (amplifiers) 132 and 134. The drawing unit 150 includes an electron column 102 and a drawing chamber 103. In the electron column 102, there are an electron gun 201, an illumination lens 202, a first aperture 203, a projection lens 204, a shaping deflector 205, a second aperture 206, an objective lens 207, a sub deflector 212, and a main deflector. 214 is arranged. In the drawing chamber 103, an XY stage 105 is arranged so as to be movable. A reflection mirror 209 is disposed on the XY stage 105. On the XY stage 105, the sample 101 is mounted with, for example, three-point support. As the sample 101, for example, an exposure mask for transferring a pattern to a wafer is included. Further, this mask includes, for example, mask blanks on which no pattern is formed. The magnetic disk device 109 stores drawing data. In the deflection control circuit 110, a sub-deflection calculator 112 and a main deflection calculator 114 are arranged. The drawing control circuit 120 controls the drawing unit 150 and the deflection control circuit 110. In particular, the sub deflector 212 and the main deflector 214 are controlled via the deflection control circuit 110. Here, FIG. 1 shows components necessary for explaining the first embodiment. Needless to say, the drawing apparatus 100 may normally include other necessary configurations.

  Further, the sub deflection calculation unit 112 and the main deflection calculation unit 114 may be implemented by hardware using an electric circuit. Alternatively, the function of the function may be executed by the sub-deflection calculation unit 112 serving as a computer. Or you may make it implement by the combination of the hardware and software by an electric circuit. Alternatively, a combination of such hardware and firmware may be used. Similarly, the main deflection calculation unit 114 serving as a computer may execute processing of the function. Or you may make it implement by the combination of the hardware and software by an electric circuit. Alternatively, a combination of such hardware and firmware may be used.

  An electron beam 200 emitted from an electron gun 201 that is an example of an irradiation unit illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole, by an illumination lens 202. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first aperture 203 is projected onto the second aperture 206 by the projection lens 204. The position of the first aperture image on the second aperture 206 is deflection-controlled by the shaping deflector 205, and the beam shape and size can be changed. As a result, the electron beam 200 is shaped. The electron beam 200 of the second aperture image that has passed through the second aperture 206 is focused by the objective lens 207 and deflected by the main deflector 214 and the sub deflector 212 controlled by the deflection control circuit 110. . As a result, the desired position of the sample 101 on the continuously moving XY stage 105 is irradiated. Here, the main deflector 214 deflects the electron beam 200 to the SF reference position including the figure to be drawn, for example, the center position. The sub deflector 212 deflects from the SF reference position to the figure position. The laser length measuring system 130 irradiates the reflection mirror 209 with laser light and receives the reflected light reflected from the reflection mirror 209. The position of the XY stage 105 can be measured by the irradiation light and the reflected light.

  However, if the reflection mirror 209 is distorted, an error is caused at the position where the reflection is measured. The reflection mirror 209 has a length equal to or longer than that of the sample 101 along the sample 101. In many cases, the distortion gradually changes throughout the reflection mirror 209. Therefore, the entire drawing area is affected by the distortion. Further, when the sample 101 to be drawn is a mask for EUV (Extreme Ultra Violet), for example, the deflection of the mask also causes an error. Since EUV light is transmitted and absorbed by many objects with light divided into a soft X-ray region, it is no longer possible to form a projection optical system. Therefore, a reflection optical system has been proposed for an exposure method using EUV light. Therefore, the mask used is not a system in which the periphery is held at three or four points in order to transmit transmitted light as in the prior art, and an attempt is made to chuck most of the back surface with a flat surface. For example, an electrostatic chuck is used to fix the EUV mask. In this way, the EUV mask is held at 3 or 4 points at the time of drawing, and most of the back surface is chucked by a flat surface at the time of exposure. Therefore, the mask of the mask when held at 3 or 4 points at the time of drawing is used. Deflection causes an error. In the first embodiment, the error due to the distortion of the reflection mirror 209 or the deflection of the sample 101 is corrected at an arbitrary position in the SF.

  FIG. 2 is a flowchart showing main steps of the drawing method according to the first embodiment. 2, the drawing method according to the first embodiment includes a drawing data processing step (S102), a main deflection position correction calculation step (S302), a D / A conversion step (S306), and a sub deflection position correction calculation step ( A series of steps such as S402), a D / A conversion step (S406), and a drawing step (S502) are performed.

  Here, first, it is necessary to measure in advance the amount of position error caused by the distortion of the reflection mirror 209 of the drawing apparatus 100 to be used. Further, when the sample 101 is an EUV mask, it is necessary to measure in advance the amount of position error including deflection due to three-point support.

  FIG. 3 is a conceptual diagram for explaining a method of measuring a global positional shift amount using a dummy substrate in the first embodiment. It is preferable to use a dummy substrate 300 having the same size and shape as the sample 101 to be actually drawn. What has a drawing area at least equal to or greater than that of the sample 101 may be used. Then, as shown in FIG. 3, the sample is placed at the same position as the sample 101 by the same support method, for example, three-point support. Although not shown in FIG. 1, the reflection mirror 209 has a reflection surface in each direction so that the x direction and the y direction can be measured. Then, a plurality of figures 302 are drawn by the drawing apparatus 100 so as to be scattered over substantially the entire drawing area of the dummy substrate 300. Here, a plurality of figures 302 are drawn at a pitch P in the xy direction. For example, it is good to draw a 1 micrometer square figure so that it may each line up with a 5-mm pitch in xy direction. If the dummy substrate 300 has a drawing area of 150 mm square, 30 pieces are arranged in the xy direction and 900 figures 302 are drawn. Here, when drawing the figure 302, it is necessary to move the XY stage 105 so that the drawing area falls within the deflection area of the electron beam 200. Therefore, for example, when drawing the upper left part of the dummy substrate 300 in FIG. 3, the laser beam is near the A part of the reflection mirror 209 for the x direction measurement and near the D part of the reflection mirror 209 for the y direction measurement. Is irradiated. On the other hand, when drawing the central portion of the dummy substrate 300 in FIG. 3, laser light is irradiated near the B portion of the reflection mirror 209 for the x direction measurement and near the E portion of the reflection mirror 209 for the y direction measurement. Is done. When the lower right portion of the dummy substrate 300 in FIG. 3 is drawn, laser light is irradiated near the C portion of the reflection mirror 209 for the x direction measurement and near the F portion of the reflection mirror 209 for the y direction measurement. Is done. As described above, the irradiation position on the reflection mirror 209 changes depending on the portion to be drawn. Therefore, it is possible to measure the amount of misalignment caused by the distortion of the reflection mirror by inspecting the positions of the drawn figures 302. Here, when correcting the deterioration of the positional accuracy occurring in the electron optical system, one mark provided on the XY stage 105 is scanned with the electron beam 200 and the amount of positional deviation is measured. . However, in this case, since the XY stage 105 remains in one place, the influence of the distortion of the entire reflection mirror 209 is not known. In this regard, as in the present embodiment, by drawing a plurality of figures 302 with the drawing apparatus 100 so as to be scattered over substantially the entire drawing area of the dummy substrate 300, it is possible to grasp the influence of the distortion of the reflection mirror 209 as a whole. Can do. Similarly, the deflection of the dummy substrate 300 by the three-point support can be grasped by drawing a plurality of figures 302 with the drawing apparatus 100 so as to be scattered over substantially the entire drawing area. If the drawn dummy substrate 300 is inspected by the same support method as that of the drawing apparatus 100, the influence of the distortion of the entire reflection mirror 209 excluding deflection can be grasped. If the drawn dummy substrate 300 is chucked and inspected so that the entire back surface is flat, the influence including the deflection can be grasped. Further, if the difference between the two results is obtained, the influence of only the deflection can be grasped.

  FIG. 4 is a diagram illustrating an example of the global position error in the first embodiment. When the global distortion or deflection as described above is generated in the drawing area of the sample 101, the desired pattern 11 is drawn as a pattern in which the distortion shown by the pattern 10 is generated.

Next, a method for correcting the global position error will be described. The coordinate reference point (0, 0) is the center of the mask. When a pattern is drawn at the sample position (X ₀ , Y ₀ ) using design data, it is assumed that a pattern is actually formed at the position (X ₁ ^* , Y ₁ ^* ) on the sample 101. Alternatively, when this sample is used in another apparatus (for example, an optical stepper or EUV stepper), a pattern is formed at a position (X ₁ ^* , Y ₁ ^* ) in the coordinate system of the apparatus. As an example, for example, if this positional relationship can be expressed up to the third order with respect to coordinates, (X ₁ ^* , Y ₁ ^* ) is (X ₀ , Y ₀ ), and the following expressions (0-1) and It is expressed as (0-2).

(0-1) X ₁ ^* = A ^* + B ^* ₁ X ₀ + B ^* ₂ Y ₀ + C ^* ₁ X ₀ ² + C ^* ₂ X ₀ Y ₀
+ C ^* ₃ Y ₀ ² + D ^* ₁ X ₀ ³ + D ^* ₂ X ₀ ² Y ₀
+ D ^* ₃ X ₀ Y ₀ ² + D ^* ₄ Y ₀ ³
(0-2) Y ₁ ^* = P ^* + Q ^* ₁ Y ₀ + Q ^* ₂ X ₀ + R ^* ₁ Y ₀ ² + R ^* ₂ X ₀ Y ₀
+ R ^* ₃ X ₀ ² + S ^* ₁ Y ₀ ³ + S ^* ₂ X ₀ Y ₀ ²
+ S ^* ₃ X ₀ ² Y ₀ + S ^* ₄ X ₀ ³

Here, the _{^{coefficient, A *, B *, ···}} , D * 4, P *, Q * 1, ···, S * 4 are obtained from a experimental. First, a plurality of figures 302 scattered over substantially the entire drawing area of the dummy substrate 300 are drawn without correction, and a position shift (pattern distortion caused by a global position error) is fitted from the positions of the formed figures. And ask.
Conversely, it is assumed that the position error can be corrected by moving the designed position (X ₀ , Y ₀ ) on the mask to be the sample 101 to (X ₁ , Y ₁ ). It can correct | amend by following correction | amendment relational expression (1-1) and Formula (1-2).

(1-1) X ₁ = A + B ₁ X ₀ + B ₂ Y ₀ + C ₁ X ₀ ² + C ₂ X ₀ Y ₀ + C ₃ Y ₀ ²
+ D ₁ X ₀ ³ + D ₂ X ₀ ² Y ₀ + D ₃ X ₀ Y ₀ ² + D ₄ Y ₀ ³
(1-2) Y ₁ = P + Q ₁ Y ₀ + Q ₂ X ₀ + R ₁ Y ₀ ² + R ₂ X ₀ Y ₀ + R ₃ X ₀ ²
+ S ₁ Y ₀ ³ + S ₂ Y ₀ ² X ₀ + S ₃ Y ₀ X ₀ ² + S ₄ X ₀ ³

A to D and P to S are coefficients of a cubic polynomial, and the values of these coefficients are X ₁ * = X ₀ when this equation is substituted into (0-1) and (0-2), It is determined so that Y ₁ * = Y ₀ or as close to this relationship as possible.

Here, a certain SF (small area) is considered. Assume that the design reference position of the SF is (X _0c , Y _0c ). Here, for example, the center of the SF is set as the reference position of the SF. However, the reference position of SF is not limited to the center, and other points may be used as the reference position. For example, any of the four corners of the SF or the center of gravity of the SF may be used. It is assumed that this reference position can be corrected by moving it to the position (X _1c , Y _1c ), and that position is formed on the sample at the position (X _0c , Y _0c ) as designed. Then, (X _1c , Y _1c ) is expressed as the following formula (2-1) and formula (2-2) using the formula (1-1) and formula (1-2).

_{(2-1) X 1c = A +} B 1 X 0c + B 2 Y 0c + C 1 X 0c 2 + C 2 X 0c Y 0c
+ C ₃ Y _0c ² + D ₁ X _0c ³ + D ₂ X _0c ² Y _0c
+ D ₃ X _0c Y _0c ² + D ₄ Y _0c ³
_{(2-2) Y 1c = P +} Q 1 Y 0c + Q 2 X 0c + R 1 Y 0c 2 + R 2 X 0c Y 0c
+ R ₃ X _0c ² + S ₁ Y _0c ³ + S ₂ X _0c Y _0c ²
+ S ₃ X _0c ² Y _0c + S ₄ X _0c ³

Accordingly, the center (X _0c , Y _0c ) of the SF in the drawing area of the sample 101 to be drawn which is deflected by the main deflector 214 is the correction parameters A, B ₁ , B ₂ , C ₁ , C ₂ , C ₃ , D ₁ , D ₂ , D ₃ , D ₄ and P, Q ₁ , Q ₂ , R ₁ , R ₂ , R ₃ , S ₁ , S ₂ , S ₃ , S ₄ depending on the position (X _1c , Y _1c ) Can be corrected. The position (X _1c , Y _1c ) is an SF correction reference position.

Next, global position error correction for an arbitrary position M in the SF will be described. Consider a position separated by a relative position (x ₀ , y ₀ ) from the SF reference point (for example) center position. When the reference position is the center of SF, no global position correction is required, and there is no optical distortion, (x ₀ , y ₀ ) corresponds to the deflection amount from the center of the subfield. Since this position M is (X _0c + x ₀ , Y _0c + y ₀ ) as a design mask coordinate, if the corrected position on the mask is (X ₁ , Y ₁ ), (X, Y ) Is equivalent to the formula (1-1) and the formula (1-2) in which X ₀ is replaced with (X _0c + x ₀ ) and Y ₀ is replaced with (Y _0c + y ₀ ). That is, it is represented by the following formula (3-1) and formula (3-2).

(3-1)
X ₁ = A + B ₁ (X _0c + x ₀ ) + B ₂ (Y _0c + y ₀ ) + C ₁ (X _0c , + x ₀ ) ²
+ C ₂ (X _0c , + x ₀ ) (Y _0c + y ₀ ) + C ₃ (Y _0c + y ₀ ) ²
+ D ₁ (X _0c + x ₀ ) ³ + D ₂ (X _0c , + x ₀ ) ² (Y _0c + y ₀ )
+ D ₃ (X _0c + x ₀ ) (Y _0c + y ₀ ) ² + D ₄ (Y _0c + y ₀ ) ³
(3-2)
Y ₁ = P + Q ₁ (Y _0c + y ₀ + Q ₂ (X _0c + x ₀ ))
+ R ₁ (Y _0c + y ₀ ) ²
+ R ₂ (X _0c + x ₀ ) (Y _0c + y ₀ ) + R ₃ (X _0c , + x ₀ ) ²
+ S ₁ (Y _0c + y ₀ ) ³ + S ₂ (X _0c + x ₀ ) (Y _0c + y ₀ ) ²
+ S ₃ (X _0c , + x ₀ ) ² (Y _0c + y ₀ ) + S ₄ (X _0c + x ₀ ) ³

If the corrected position (x ₁ , y ₁ ) on the mask is separated from the corrected center position (X _1c , Y _1c ) of the SF by a relative distance (x ₁ ′, y ₁ ′) ( x ₁ ′, y ₁ ′) is expressed by the following equations (4-1) and (4-2).

(4-1) x ₁ ′ = X ₁ −X _1c
(4-2) y ₁ ′ = Y ₁ −Y _1c

  Then, when Expression (2-1), Expression (2-2), Expression (3-1), and Expression (3-2) are substituted into Expression (4-1) and Expression (4-2), the following expression It can be expressed as (5-1) and formula (5-2).

(5-1)
x ₁ '= X ₁ -X _1c
= A + B ₁ (X _0c + x ₀ ) + B ₂ (Y _0c + y ₀ )
+ C ₁ (X _0c + x ₀ ) ² + C ₂ (X _0c + x ₀ ) (Y _0c + y ₀ )
+ C ₃ (Y _0c + y ₀ ) ² + D ₁ (X _0c + x ₀ ) ³
+ D ₂ (X _0c + x ₀ ) ² (Y _0c + y ₀ )
+ D ₃ (X _0c + x ₀ ) (Y _0c + y ₀ ) ² + D ₄ (Y _0c + y ₀ ) ³
_{- {A + B 1 X 0c} + B 2 Y 0c + c 1 X 0 2 + c 2 X 0c Y 0c
+ C ₃ Y _0c ² + D ₁ X _0c ³ + D ₂ X _0c ² Y _0c
+ D ₃ X _0c Y _0c ² + D ₄ Y _0c ³ }
(5-2)
y ₁ ′ = Y ₁ −Y _1c
= P + Q ₁ (Y _0c + y ₀ ) + Q ₂ (X _0c + x ₀ )
+ R ₁ (Y _0c + y ₀ ) ² + R ₂ (X _0c + x ₀ ) (Y _0c + y ₀ )
+ R ₃ (X _0c + x ₀ ) ²
+ S ₁ (Y _0c + y ₀ ) ³
+ S ₂ (X _0c + x ₀ ) (Y _0c + y ₀ ) ²
+ S ₃ (X _0c + x ₀ ) ² (Y _0c + y ₀ )
+ S ₄ (X _0c + x ₀ ) ³
_{- {P + Q 1 Y 0c} + Q 2 X 0c + R 1 Y 0c 2 + R 2 X 0c Y 0c
+ R ₃ X _0c ²
+ S ₁ Y _0c ³
+ S ₂ X _0c Y _0c ²
+ S ₃ X _0c ² Y _0c
+ S ₄ X _0c ³ }

Here, in order to avoid complications, the right sides of the equations (4-1) and (4-2) are respectively _{expressed as} F (X _0c , x ₀ , Y _0c , y ₀ ) and G (X _0c , x ₀ , Y _0c , y ₀ ). That is, they are defined as the following expressions (6-1) and (6-2).

(6-1) x ₁ ′ = F (X _0c , x ₀ , Y _0c , y ₀ )
(6-2) y ₁ ′ = G (X _0c , x ₀ , Y _0c , y ₀ )

These functions can be the product of the up to the third order _{x 0} and _{y 0} expressed by the following equation (7-1) and (7-2).

(7-1)
F (X _0c , x ₀ , Y _0c , y ₀ ) = x ₁ ′ = A ′ + B ₁ ′ x ₀ + B ₂ ′ y ₀
+ C ₁ 'x ₀ ²
+ C ₂ 'x ₀ y ₀ + C ₃ ' y ₀ ² + D ₁ 'x ₀ ³
+ D ₂ 'x ₀ ² y ₀ + D ₃ ' x ₀ y ₀ ²
+ D ₄ 'y ₀ ³
(7-2)
_{G (X 0c, x 0,} Y 0c, y 0) = y 1 '= P' + Q 1 'y 0 + Q 2' x 0
+ R ₁ 'y ₀ ²
+ R ₂ 'x ₀ y ₀
+ R ₃ 'x ₀ ²
+ S ₁ 'y ₀ ³
+ S ₂ 'x ₀ y ₀ ² + S ₃ ' x ₀ ² y ₀
+ S ₄ 'x ₀ ³

  These coefficients can be expressed as the following formulas (8-1) to (8-20).

(8-1) A ′ = 0
(8-2) B ₁ ′ = B ₁ + 2C ₁ X _0c + C ₂ Y _0c + 3D ₁ X _0c ²
+ 2D ₂ X _0c Y _0c + D ₃ Y _0c ²
(8-3) B ₂ ′ = B ₂ + 2C ₃ Y _0c + C ₂ X _0c + 3D ₄ Y _0c ²
+ 2D ₃ X _0c Y _0c + D ₂ X _0c ²
(8-4) C ₁ ′ = C ₁ + 3D ₁ X _0c + D ₂ Y _0c
(8-5) C ₂ ′ = C ₂ + 2D ₂ X _0c + 2D ₃ Y _0c
(8-6) C ₃ '= C ₃ + 3D ₄ Y _0c + D ₃ X _0c
(8-7) D ₁ '= D ₁
(8-8) D ₂ '= D ₂
(8-9) D ₃ '= D ₃
(8-10) D ₄ '= D ₄
(8-11) P ′ = 0
(8-12) Q ₁ ′ = Q ₁ + 2R ₁ Y _0c + R ₂ X _0c + 3S ₁ Y _0c ²
+ 2S ₂ X _0c Y _0c + S ₃ X _0c ²
(8-13) Q ₂ ′ = Q ₂ + 2R ₃ X _0c + R ₂ Y _0c + 3S ₄ X _0c ²
+ 2S ₃ X _0c Y _0c + S ₂ Y _0c ²
(8-14) R ₁ ′ = R ₁ + 3S ₁ Y _0c + S ₂ X _0c
(8-15) R ₂ ′ = R ₂ + 2S ₂ Y _0c + 2S ₃ X _0c
(8-16) R ₃ '= R ₃ + 3S ₄ X _0c + S ₃ Y _0c
(8-17) S ₁ ′ = S ₁
(8-18) S ₂ '= S ₂
(8-19) S ₃ '= S ₃
(8-20) S ₄ '= S ₄

Therefore, by calculating the above-described formulas (7-1) and (7-2), an arbitrary position (x in the corrected SF from the center position (X _1c , Y _1c ) of the corrected SF ₁ , y ₁ ), the relative distance (x ₁ ′, y ₁ ′) can be calculated. By this calculation, the relative distance (x ₀ , y ₀ ) from the center position (X _1c , Y _1c ) of the SF to an arbitrary position in the SF can be corrected. Thereby, global distortion at an arbitrary position in the SF can be corrected. Here, when calculating the relative distance (x ₁ ′, y ₁ ′), the coefficient of the correction formula for correcting the center position (X _0c , Y _0c ) of SF and the center position (X _0c , Y _0c ) And the relative distance (x ₀ , y ₀ ) from the center position (X _1c , Y _1c ) to an arbitrary position in the SF can be corrected. Specifically, as shown in Expression (8-1) to Expression (8-20), correction parameters A ′, B ₁ ′, B ₂ ′ in Expression (7-1) and Expression (7-2) are used. , C ₁ ′, C ₂ ′, C ₃ ′, D ₁ ′, D ₂ ′, D ₃ ′, D ₄ ′ and P ′, Q ₁ ′, Q ₂ ′, R ₁ ′, R ₂ ′, R ₃ ', S ₁ ', S ₂ ', S ₃ ', S ₄ 'are the center position (X _0c , Y _0c ) of the SF before correction of SF, and the expressions (1-1) and (1-2) Correction parameters A, B ₁ , B ₂ , C ₁ , C ₂ , C ₃ , D ₁ , D ₂ , D ₃ , D ₄ and P, Q ₁ , Q ₂ , R ₁ , R ₂ , R ₃ , S ₁ , S ₂ , S ₃ , S ₄ .

  Here, when the beam is irradiated to an arbitrary position (x ′, y ′) after global correction inside the subfield inside the drawing apparatus 100, as described above, distortion of the electron optical system also exists. Therefore, in addition to the distortion of the reflection mirror 209 and the like, the distortion of the electron optical system is also corrected to enable drawing with higher accuracy. Therefore, here, the coefficient of the correction equation for global correction such as the distortion of the reflection mirror 209 described above is further combined with the coefficient of the correction equation for distortion correction of the electron optical system. The correction relational expression for correcting the distortion of the electron optical system can be expressed by the following expressions (9-1) and (9-2).

(9-1)
X _E = H (x ′, y ′)
= A + b ₁ x ′ + b ₂ y ′ + c ₁ x ′ ² + c ₂ x′y ′ + c ₃ y ′ ²
+ D ₁ x ′ ³ + d ₂ x ′ ² y ′ + d ₃ x′y ′ ² + d ₄ y ′ ³
(9-2)
Y _E = I (x ′, y ′)
= P + q ₁ y ′ + q ₂ x ′
+ R ₁ y ′ ² + r ₂ x′y ′ + r ₃ x ′ ²
+ S ₁ y ′ ³ + s ₂ x′y ′ ² + s ₃ x ′ ² y ′
+ S ₄ x ' ³

The correction parameters a, b ₁ , b ₂ ,..., D ₃ , d ₄ and p, q ₁ , q ₂ , ..., s ₃ , s ₄ in the expressions (9-1) and (9-2) are as described above. As described above, one mark provided on the XY stage 105 is set at a plurality of positions by moving the XY stage 105 within the main deflection area and the sub deflection area, and the electron beam 200 is scanned at each position. Then, the amount of displacement is measured. And what is necessary is just to obtain | require by fitting the obtained some positional offset amount.

Here, if x ′ and y ′ in formula (9-1) and formula (9-2) are replaced with x ₁ ′ and y ₁ ′ using formula (6-1) and formula (6-2), Expressions (9-1) and (9-2) can be expressed as the following expressions (10-1) and (10-2).

(10-1)
X _E = H (x ′, y ′)
_{= H (F (X 0c,} x 0, Y 0c, y 0), G (X 0c, x 0, Y 0c, y 0))
(10-2)
Y _E = I (x ′, y ′)
= I (F (X _0c , x ₀ , Y _0c , y ₀ ), G (X _0c , x ₀ , Y _0c , y ₀ ))

That is, Expressions (10-1) and (10-2) are polynomials related to x ₀ and y ₀ . Here, the fourth and higher order terms are neglected as a minute amount and rearranged with respect to x ₀ and y ₀ , and can be expressed as the following equations (11-1) and (11-2).

(11-1)
X _E = H (x ′, y ′)
= A '+ b ₁ ' x ₀ + b ₂ 'y ₀ + c ₁ ' x ₀ ² + c ₂ 'x ₀ y ₀ + c ₃ ' y ₀ ²
+ D ₁ 'x ₀ ³ + d ₂ ' x ₀ ² y ₀ + d ₃ 'x ₀ y ₀ ² + d ₄ ' y ₀ ³
(11-2)
Y _E = I (x ′, y ′)
= P '+ q ₁ ' y ₀ + q ₂ 'x ₀
+ R ₁ 'y ₀ ² + r ₂ ' x ₀ y ₀ + r ₃ 'x ₀ ²
+ S ₁ 'y ₀ ³ + s ₂ ' x ₀ y ₀ ²
+ S ₃ 'x ₀ ² y ₀ + s ₄ ' x ₀ ³

These coefficients a ′, b ₁ ′, b ₂ ′,..., D ₃ ′, d ₄ ′ and p ′, q ₁ ′, q ₂ ′, ..., s ₃ ′, s ₄ ′ are a, b ₁ , B ₂ , ..., d ₃ , d ₄ , p, q ₁ , q ₂ , ..., s ₃ , s ₄ , A ', B ₁ ', B ₂ ', ..., D ₃ ', D ₄ ', P ', Q ₁ ', Q ₂ ', ..., S ₃ ', S ₄ '. a ′, b ₁ ′, b ₂ ′,..., d ₃ ′, d ₄ ′ are as follows.

(Representation on the coefficient of _{X E)}
a '= a
b ₁ '= b ₁ B ₁ ' + b ₂ Q ₂ '
b ₂ '= b ₁ B ₂ ' + b ₂ Q ₁ '
_{c 1 '= b 1 C 1} ' + b 2 R 3 '+ c 1 B 1' 2 + c 2 B 1 'Q 2' + c 3 Q 2 '2
_{c 2 '= b 1 C 2} ' + b 2 R 2 '+ 2c 1 B 1' B 2 '
+ C ₂ (B ₁ 'Q ₁ ' + B ₂ 'Q ₂ ') + 2c ₃ Q ₁ 'Q ₂ '
_{c 3 '= b 1 C 3} ' + b 2 R 1 '+ c 1 B 2' 2 + c 2 B 2 'Q 1' + c 3 Q 1 '2
d ₁ ′ = b ₁ D ₁ ′ + b ₂ S ₄ ′ +2 c ₁ B ₁ ′ C ₁ ′ +2 c ₃ Q ₂ ′ R ₃ ′
+ C ₂ (B ₁ 'R ₃ ' + Q ₂ 'C ₁ ') + d ₁ B ₁ ' ³
+ D ₄ Q ₂ ' ³ ++ d ₂ B ₁ ' ² Q ₂ '+ d ₃ B ₁ ' Q ₂ ' ²
d ₂ '= b ₁ D ₂ ' + b ₂ S ₃ '+ 2c ₁ (B ₁ ' C ₂ '+ B ₂ ' C ₁ ')
+ 2c ₃ (Q ₁ 'R ₃ ' + Q ₂ 'R ₂ ')
+ C ₂ (B ₁ 'R ₂ ' + B ₂ 'R ₃ ' + Q ₁ 'C ₁ ' + Q ₂ 'C ₂ ')
+ 3d ₁ B ₁ ' ² B ₂ ' + 3d ₄ Q ₁ 'Q ₂ ' ²
+ D ₂ (B ₁ ' ² Q ₁ ' + 2B ₁ 'B ₂ ' Q ₂ ')
+ D ₃ (2B ₁ 'Q ₁ ' Q ₂ '+ B ₂ ' Q ₂ ' ² )
d ₃ '= b ₁ D ₃ ' + b ₂ S ₂ '+ 2c ₁ (B ₁ ' C ₃ '+ B ₂ ' C ₂ ')
+ 2c ₃ (Q ₁ 'R ₂ ' + Q ₂ 'R ₁ ')
+ C ₂ (B ₁ 'R ₁ ' + B ₂ 'R ₂ ' + Q ₁ 'C ₂ ' + Q ₂ 'C ₃ ')
+ 3d ₁ B ₁ 'B ₂ ' ² + 3d ₄ Q ₁ ' ² Q ₂ '
+ D ₂ (B ₂ ' ² Q ₂ ' + 2B ₁ 'B ₂ ' Q ₁ ')
+ D ₃ (2B ₂ 'Q ₁ ' Q ₂ '+ B ₁ ' Q ₁ ' ² )
_{d 4 '= b 1 D 4} ' + b 2 S 1 '+ 2c 1 B 2' C 3 '
+ 2c ₃ Q ₁ 'R ₁ ' + c ₂ (B ₂ 'R ₁ ' + Q ₁ 'C ₃ ')
+ D ₁ B ₂ ' ³ + d ₄ Q ₁ ' ³ + d ₂ B ₂ ' ² Q ₁ ' + d ₃ B ₂ 'Q ₁ ² '

p ′, q ₁ ′, q ₂ ′,..., s ₃ ′, s ₄ ′ can be obtained from the subjectivity as follows using this equation.

In addition, the following replacement is introduced.
(Replacement 1)
A '<->P',
B ₁ '<-> Q ₂ ', B ₂ '<-> Q ₁ '
C ₁ '<-> R ₃ ', C ₂ '<-> R ₂ , C ₃ '<-> R ₁ '
D ₁ '<-> S ₄ ', S ₂ '<-> S ₃ ', D ₃ '<-> S ₂ ', D ₄ '<-> S ₁ '

Here, α <−> β indicates that the symbol α is replaced with β, and β is replaced with α. If this replacement is applied to Equation (7-1) and Equation (7-2), Equation (7-1) becomes Equation (7-2), and Equation (7-2) becomes Equation (7-1) and Equation (7-1). Become. That is, x ′ and y ′ are exchanged by (Replacement 1). This has the effect of replacing x ′ and y ′ as shown in the following (Replacement 1) ′.
(Replacement 1) '
x '<->y'

Consider the following replacement.
(Replacement 2)
a-> p
b _1- > q ₁ , b _2- > q ₂
c _1- > r ₁ , c _2- > r ₂ , c _3- > r _{3
d 1 -> s 1, d} 2 -> s 2, d 3 -> s 3 ', d 4 -> s 4

Here α-> β indicates that α is replaced by β.
If the above (replacement 1) ′ (that is, replacement 1) and (replacement 2) are applied to expression (9-1), expression (9-1) becomes expression (9-2).

A representation equation (9-1) by a polynomial of _{x 0} and _{y 0} is an expression (11-1). The coefficients are a ′, b1 ′..., But considering that the roles of x ₀ and y ₀ are reversed in the equations (9-1) and (9-2), The relationship of the coefficients is as follows.

(Action 1)
a '->p'
b ₁ '-> q ₂ ', b ₂ '-> q ₁ '
c ₁ '-> r ₃ ', c ₂ '-> r ₂ ', c ₃ '-> r ₁ '
_{d 1 '-> s 4'} , d 2 '-> s 3', d 3 '-> s 2', d 4 '-> s 1'

Therefore, with respect to the (expression for the coefficient of _{X E),} subjected to a (replacement 1) and (replacement 2), is obtained (representation of coefficients _{X E)} By using the (Action 1).

Here are some examples.
(Example 1)
a '= a
According to (Correspondence 1), a ′ is p ′. Let a be p by (Replacement 2). The result p ′ = p is obtained.

(Example 2)
b ₁ '= b ₁ B ₁ ' + b ₂ Q ₂ '
According to (Correspondence 1), b ₁ ′ is set to q ₂ ′. (Replacement 1) sets B ₁ ′ to Q ₂ ′ and Q ₂ ′ to B ₁ ′. (Replacement 2) sets b ₁ to p ₁ and b ₂ to p ₂ .
p ₂ '= b ₁ Q ₂ ' + b ₂ B ₁ '

Thus (expression for the coefficient of X _E) only replaced could ask all.

(Representation on the coefficient of _{Y E)}
p '= p
q ₂ '= q ₁ Q ₂ ' + q ₂ B ₁ '
q ₁ '= q ₁ Q ₁ ' + q ₂ B ₂ '
_{r 3 '= q 1 R 3} ' + q 2 C 1 '+ r 1 Q 2' 2 + r 2 B 1 'Q 2' + r 3 B 1 '2
r ₂ '= q ₁ R ₂ ' + q ₂ C ₂ '+ 2r ₁ Q ₁ ^' Q ₂ ^'
+ R ₂ (Q ₂ 'B ₂ ' + Q ₁ 'B ₁ ') + 2r ₃ B ₂ 'B ₁ '
_{r 1 '= q 1 R 1} ' + q 2 C 3 '+ r 1 Q 1' 2 + r 2 B 2 'Q 1' + r 3 B 2 '2
s ₄ '= q ₁ S ₄ ' + q ₂ D ₁ '+ 2r ₁ Q ₂ ' R ₃ '+ 2r ₃ B ₁ ' C ₁ '
+ R ₂ (Q ₂ 'C ₁ ' + B ₁ 'R ₃ ') + s ₁ Q ₂ ' ³ + s ₄ B ₁ ' ³
+ S ₂ Q ₂ ' ² B ₁ ' + s ₃ Q ₂ 'B ₁ ' ²
s ₃ '= q ₁ S ₃ ' + q ₂ D ₂ '+ 2r ₁ (Q ₂ ' R ₂ '+ Q ₁ ' R ₃ ')
+ 2r ₃ (B ₂ 'C ₁ ' + B ₁ 'C ₂ ')
+ R ₂ (Q ₂ 'C ₂ ' + Q ₁ 'C ₁ ' + B ₂ 'R ₃ ' + B ₁ 'R ₂ ')
+ 3s ₁ Q ₂ ' ² Q ₁ ' + 3s ₄ B ₁ ' ² B ₂ '
+ S ₂ (Q ₂ ' ² B ₂ ' + 2Q ₂ 'Q ₁ ' B ₁ ')
+ S ₃ (2Q ₂ 'B ₁ ' B ₂ '+ Q ₁ ' B ₁ ' ² )
s ₂ '= q ₁ S ₂ ' + q ₂ D ₃ '+ 2r ₁ (Q ₂ ' R ₁ '+ Q ₁ ' R ₂ ')
+ 2r ₃ (B ₂ 'C ₂ ' + B ₁ 'C ₃ ')
+ R ₂ (Q ₂ 'C ₃ ' + Q ₁ 'C ₂ ' + B ₂ 'R ₂ ' + B ₁ 'R ₁ ')
+ 3s ₁ Q ₂ 'Q ₁ ' ² + 3s ₄ B ₂ ' ² B ₁ '
+ S ₂ (Q ₁ ' ² B ₁ ' + 2Q ₂ 'Q ₁ ' B ₂ ')
+ S ₃ (2Q ₁ 'B ₁ ' B ₂ '+ Q ₂ ' B ₂ ' ² )
_{s 1 '= q 1 S 1} ' + q 2 D 4 '+ 2r 1 Q 1' R 2 '+ 2r 3 B 2' C 3 '
+ R ₂ (Q ₁ 'C ₃ ' + B ₂ 'R ₁ ') + s ₁ Q ₁ ' ³
+ S ₄ B ₂ ' ³ + s ₂ Q ₁ ' ² B ₂ '+ s ₃ Q ₁ ' B ₂ ' ²

Here, A ′, B ₁ ′, B ₂ ′,..., D ₃ ′, D ₄ ′, P ′, Q ₁ ′, Q ₂ ′, ..., S ₃ ′, S ₄ ′ are expressed by the formula (8-1) ) To (8-20). That is, coefficients for correcting global position errors in the entire mask, A, B ₁ , B _2, etc., and the values (X _0c , Y _0c ) of the reference position (subfield center) of the subfield in the mask coordinates ). That is, by changing the distortion correction coefficient of the optical system inside the subfield according to the value at the mask coordinate of the subfield, it is possible to achieve global position error correction in addition to the distortion correction of the optical system. In other words, more accurate position correction is possible by controlling the distortion correction coefficient of the optical system inside the subfield by the value at the mask coordinate of the subfield. Accordingly, the correction parameters a ′, b ₁ ′, b ₂ ′,..., D ₃ ′ of the expressions (11-1) and (11-2), and the expressions (11-1) and (11-2), d ₄ ′ and p ′, q ₁ ′, q ₂ ′,..., s ₃ ′, s ₄ ′ may be set in the sub deflection operation unit 112.

  Similarly, there is distortion of the electron optical system at the center position which is the reference position of the SF. Therefore, in addition to the distortion of the reflection mirror 209 and the like, the distortion of the electron optical system is also corrected to enable drawing with higher accuracy. Therefore, here, the coefficient for the global correction such as the distortion of the reflection mirror 209 described above is further combined with the coefficient of the correction equation for correcting the distortion of the electron optical system.

In this case, the same processing as in the above example can be performed.
Let (X _0M , Y _0M ) be the center position of the designed field. The position (X _1M , Y _1M ) obtained by performing global position correction on this position is expressed as follows using equations (1-1) and (1-2).

(12-1)
X _1M = A + B ₁ X _0M + B ₂ Y _0M + C ₁ X _0M ² + C ₂ X _0M Y _0M
+ C ₃ Y _0M ² + D ₁ X _0M ³ + D ₂ X _0M ² Y _0M + D ₃ X _0M Y _0M ²
+ D ₄ Y _0M ³
(12-2)
Y _1M = P + Q ₁ X _0M + Q ₂ Y _0M + R ₁ X _0M ² + R ₂ X _0M Y _0M
+ R ₃ Y _0M ² + S ₁ X _0M ³ + S ₂ X _0M ² Y _0M + S ₃ X _0M Y _0M ²
+ S ₄ Y _0M ³

In an apparatus employing step and repeat, the stage is moved so that the optical center is at this position (X _1M , Y _1M ), a voltage is applied to the main deflection deflector, and the beam (as described below) is applied. The subfield may be set by deflecting. On the other hand, in the stage continuous movement method, processing is performed as follows. First, when there is a subfield of a design reference position (X _0M , Y _0M ), (X _1M , Y _1M ) is calculated in accordance with Expression (12-1) and Expression (12-2). While the stage is continuously moved, the position (coordinate value) of the optical center can be detected by the laser interferometer. When this coordinate value becomes (X _1M , Y _1M ), the subfield may be set by deflecting the beam (as described below).
Here, the design subfield position (reference position) is defined as (X _0c , Y _0c ) on the mask. Assuming that the position (X _1c , Y _1c ) is obtained by performing global position correction for this position, the position (X _1c , Y _1c ) is expressed by the following expression according to the expressions (1-1) and (1-2): Will be.

(13-1)
_{X 1c = A + B 1 X} 0c + B 2 Y 0c + C 1 X 0c 2 + C 2 X 0c Y 0c
+ C ₃ Y _0c ² + D ₁ X _0c ³ + D ₂ X _0c ² Y _0c + D ₃ X _0c Y _0c ²
+ D ₄ Y _0c ³
(13-2)
_{Y 1c = P + Q 1 X} 0c + Q 2 Y 0c + R 1 X 0c 2 + R 2 X 0c Y 0c
+ R ₃ Y _0c ² + S ₁ X _0c ³ + S ₂ X _0c ² Y _0c + S ₃ X _0c Y _0c ²
+ S ₄ Y _0c ³

The deflection amounts (ΔX _1c , ΔY _1c ) by the main deflector at the time of drawing are defined below.

(14-1) ΔX _1c = X _1c -X _1M
(14-2) ΔY _1c = Y _1c -Y _1M

  This is expressed as follows using the equations (12-1) and (12-2).

(15-1)
ΔX _1c = A + B ₁ X _0c + B ₂ Y _0c + C ₁ X _0c ² + C ₂ X _0c Y _0c
+ C ₃ Y _0c ²
+ D ₁ X _0c ³ + D ₂ X _0c ² Y _0c + D ₃ X _0c Y _0c ² + D ₄ Y _0c ³
-X _1M
(15-2)
ΔY _1c = P + Q ₁ X _0c + Q ₂ Y _0c + R ₁ X _0c ² + R ₂ X _0c Y _0c
+ R ₃ Y _0c ²
+ S ₁ X _0c ³ + S ₂ X _0c ² Y _0c + S ₃ X _0c Y _0c ² + S ₄ Y _0c ³
-Y _1M

The difference (ΔX _0c , ΔY _0c ) between the reference position (X _0c , Y _0c ) of the designed subfield field and the designed field center position (X _0M , Y _0M ) is defined below.

(16-1) ΔX _0c = X _0c -X _0M
(16-2) ΔY _0c = Y _0c -Y _0M

  Using this formula (16-1) and formula (16-2) and formula (13-1) and formula (13-2), formula (15-1) and formula (15-2) are as follows: Deformed.

(17-1) ΔX _1c = A + B ₁ (ΔX _0c + X _0M ) + B ₂ (ΔY _0c + Y _0M )
+ C ₁ (ΔX _0c + X _0M ) ²
+ C ₂ (ΔX _0c + X _0M ) (ΔY _0c + Y _0M )
+ C ₃ (ΔY _0c + Y _0M ) ²
+ D ₁ (ΔX _0c + X _0M ) ³
+ D ₂ (ΔX _0c + X _0M ) ² (ΔY _0c + Y _0M )
+ D ₃ (ΔX _0c + X _0M ) (ΔY _0c + Y _0M ) ²
+ D ₄ (ΔY _0c + Y _0M ) ³
_{- {A + B 1 X 0M} + B 2 Y 0M + C 1 X 0M 2 + C 2 X 0M Y 0M
+ C ₃ Y _0M ²
+ D ₁ X _0M ³ + D ₂ X _0M ² Y _0M + D ₃ X _0M Y _0M ²
+ D ₄ Y _0M ³ }
(17-2) ΔY _1c = P + Q ₁ (ΔX _0c + X _0M ) + Q ₂ (ΔY _0c + Y _0M )
+ R ₁ (ΔX _0c + X _0M ) ²
+ R ₂ (ΔX _0c + X _0M ) (ΔY _0c + Y _0M )
+ R ₃ (ΔY _0c + Y _0M ) ²
+ S ₁ (ΔX _0c + X _0M ) ³
+ S ₂ (ΔX _0c + X _0M ) ² (ΔY _0c + Y _0M )
+ S ₃ (ΔX _0c + X _0M ) (ΔY _0c + Y _0M ) ²
+ S ₄ (ΔY _0c + Y _0M ) ³
_{- {P + Q 1 X 0M} + Q 2 Y 0M + R 1 X 0M 2 + R 2 X 0M Y 0M
+ R ₃ Y _0M ²
+ S ₁ X _0M ³ + S ₂ X _0M ² Y _0M + S ₃ X _0M Y _0M ²
+ S ₄ Y _0M ³ }

If Expression (17-1) and Expression (17-2) are arranged with respect to ΔX _0c and ΔY _0c , they are expressed as follows.

(18-1) ΔX _1c = A ″ + B ″ ₁ ΔX _0c + B ″ ₂ ΔY _0c
+ C ″ ₁ ΔX _0c ² + C ″ ₂ ΔX _0c ΔY _0c
+ C ″ ₃ ΔY _0c ²
+ D ″ ₁ ΔX _0c ³ + D ″ ₂ ΔX _0c ² ΔY _0c
+ D ″ ₃ ΔX _0c ΔY _0c ² + D ″ ₄ ΔY _0c ³
(18-2) ΔY _1c = P ″ + Q ″ ₁ ΔX _0c + Q ″ ₂ ΔY _0c
+ R ″ ₁ ΔX _0c ² + R ″ ₂ ΔX _0c ΔY _0c
+ R ″ ₃ ΔY _0c ²
+ S ″ ₁ ΔX _0c ³ + S ″ ₂ ΔX _0c ² ΔY _0c
+ S ″ ₃ ΔX _0c ΔY _0c ² + S ″ ₄ ΔY _0c ³

Here, A ″,... S ″ ₄ are expressed as follows.

(19-1) A ″ = 0
(19-2) B ₁ ″ = B ₁ + 2C ₁ X _0M + C ₂ Y _0M + 3D ₁ X _0M ²
+ 2D ₂ X _Mc Y _Mc + D ₃ Y _Mc ²
(19-3) B ₂ ″ = B ₂ + 2C ₃ Y _Mc + C ₂ X _Mc + 3D ₄ Y _Mc ²
+ 2D ₃ X _0M Y _0M + D ₂ X _0M ²
(19-4) C ₁ ″ = C ₁ + 3D ₁ X _0M + D ₂ Y _0M
(19-5) C ₂ ″ = C ₂ + 2D ₂ X _0M + 2D ₃ Y _0M
(19-6) C ₃ ″ = C ₃ + 3D ₄ Y _0M + D ₃ X _0M
(19-7) D ₁ ″ = D ₁
(19-8) D ₂ ″ = D ₂
(19-9) D ₃ ″ = D ₃
(19-10) D ₄ ″ = D ₄
(19-11) P ″ = 0
(19-12) Q ₁ ″ = Q ₁ + 2R ₁ Y _0M + R ₂ X _0M + 3S ₁ Y _0M ²
+ 2S ₂ X _0M Y _0M + S ₃ X _0M ²
(19-13) Q ₂ ″ = Q ₂ + 2R ₃ X _0M + R ₂ Y _0M + 3S ₄ X _0M ²
+ 2S ₃ X _0M Y _0M + S ₂ Y _0M ²
(19-14) R ₁ ″ = R ₁ + 3S ₁ Y _0M + S ₂ X _0M
(19-15) R ₂ ″ = R ₂ + 2S ₂ Y _0M + 2S ₃ X _0M
(19-16) R ₃ ″ = R ₃ + 3S ₄ X _0M + S ₃ Y _0M
(19-17) S ₁ ″ = S ₁
(19-18) S ₂ ″ = S ₂
(19-19) S ₃ ″ = S ₃
(19-20) S ₄ ″ = S ₄

Here, in order to correct the main deflection distortion, in order to actually deflect the subfield position (reference position) by (ΔX _1c , ΔY _1c ), it is necessary to set a different deflection amount in the deflector. When the amount of deflection to be set is (ΔX _2c , ΔY _2c ) and ΔX _1c and ΔY _1c are corrected up to the third order, the correction formula is expressed as follows.

(20-1)
ΔX _2c = a ″ + b ″ ₁ ΔX _1c + b ″ ₂ ΔY _1c + c ″ ₁ ΔX _1c ²
+ C ″ ₂ ΔX _1c ΔY _1c + c ″ ₃ ΔY _1c ² + d ″ ₁ ΔX _1c ³
+ D ″ ₂ ΔX _1c ² ΔY _1c + d ″ ₃ ΔX _1c ΔY _1c ²
+ D ″ ₄ ΔY _1c ³
(20-2)
ΔY _2c = p ″ + q ″ ₁ ΔX _1c + q ″ ₂ ΔY _1c + r ″ ₁ ΔX _1c ²
+ R ″ ₂ ΔX _1c ΔY _1c + r ″ ₃ ΔY _1c ² + s ″ ₁ ΔX _1c ³
+ S ″ ₂ ΔX _1c ² ΔY _1c + s ″ ₃ ΔX _1c ΔY _1c ²
+ S ″ ₄ ΔY _1c ³

Here, a ″,..., S ″ ₄ are parameters for correcting deflection distortion, and are values obtained by main deflection adjustment in the electron optical system. As described above, this value is set at a plurality of positions by moving the XY stage 105 within the main deflection area with one mark provided on the XY stage 105, and the electron beam 200 is scanned at each position. Then, the amount of displacement is measured. And what is necessary is just to obtain | require by fitting the obtained some positional offset amount.

Here, ΔX _1c and ΔY _1c in Formula (I-1) and Formula (I-2) are replaced with ΔX _0c and ΔY _0c using Formula (18-1) and Formula (18-2), and ΔX _0c , _{If the} fourth or higher order term is ignored as the amount of smile for ΔY _0c , the expressions (20-1) and (20-2) should be expressed as the following expressions (21-1) and (21-2). Can do.

(21-1)
ΔX _2c = a ″ ′ + b ′ ″ ₁ ΔX _1c + b ′ ″ ₂ ΔY _1c
+ C ′ ″ ₁ ΔX _1c ² + c ′ ″ ₂ ΔX _1c ΔY _1c + c ″ ′ ₃ ΔY _1c ²
+ D ′ ″ ₁ ΔX _1c ³ + d ′ ″ ₂ ΔX _1c ² ΔY _1c
+ D ''' ₃ ΔX _1c ΔY _1c ²
+ D ''' ₄ ΔY _1c ³
(21-2)
ΔY _2c == p ′ ″ + q ′ ″ ₁ ΔX _1c + q ′ ″ ₂ ΔY _1c
+ R ′ ″ ₁ ΔX _1c ²
+ R ′ ″ ₂ ΔX _1c ΔY _1c + r ′ ″ ₃ ΔY _1c ² + s ′ ″ ₁ ΔX _1c ³
+ S ′ ″ ₂ ΔX _1c ² ΔY _1c + s ′ ″ ₃ ΔX _1c ΔY _1c ²
+ S ′ ″ ₄ ΔY _1c ³

These coefficients a ''', ..., s _4' '' is, a '', ..., s '' 4, A '', ..., S ' can be represented by' _4. Formula (18-1) and Formula (18-2) are the same type as Formula (7-1) and Formula (7-2), and Formula (20-1) and Formula (20-2) are Formula (9-1). And the same form as the formula (9-2), the formula (21-1) and the formula (21-2), and the same form as the formula (11-1) and the formula (11-2), the formula (11-1) and formula (11-2) coefficients a _{'of'', ..., s 4'} '' is, a '', ..., s '' 4 expression was determined above (expression for the coefficient of _{X E)} And can be obtained by replacing various coefficients.

It is represented not only by the correction coefficients a ″,..., S ₄ ″ of the electron optical system but also by A ″,..., S ″ ₄ , that is, A,. As a result, global position correction and optical system distortion correction are realized simultaneously.

These coefficients _{a ", b 1", b} 2 ", ..., d 3", d 4 " and _{p", q 1 ", q} 2", ..., s 3 ", s 4" is, a, _{b 1 , b 2, ..., d 3} , d 4, p, q 1, q 2, ..., s 3, s 4, A, B 1, B 2, ..., D 3, D 4, P, Q 1, Q ₂ ,..., S ₃ , S ₄ .

That is, the values (X _0c , Y _0c ) in the mask coordinates of the coefficients such as A, B ₁ , B _{2 and the} like for correcting the global position error in the entire mask and the reference position (subfield center) of the subfield are used. Dependent. That is, by changing the distortion correction coefficient of the optical system inside the subfield according to the value at the mask coordinate of the subfield, it is possible to achieve global position error correction in addition to the distortion correction of the optical system. In other words, more accurate position correction is possible by controlling the distortion correction coefficient of the optical system inside the subfield by the value at the mask coordinate of the subfield. Therefore, the correction parameters a ″, b ₁ ″, b ₂ ″,..., D ₃ ″ of the equations (12-1) and (12-2), and the equations (12-1) and (12-2), d ₄ ″ and p ″, q ₁ ″, q ₂ ″,..., s ₃ ″, s ₄ ″ may be set in the main deflection calculation unit 114.

  As described above, since these coefficients (correction parameters) and the correction formula are obtained, the drawing operation in the drawing apparatus 100 will be described below.

  In S (step) 102, as a drawing data processing step, the drawing control circuit 120 reads out drawing data for one stripe from the magnetic disk device 109. Then, the read drawing data is processed and converted into data in an in-device format used when the electron beam 200 is actually shot. In the drawing data, coordinates indicating the position of the figure to be drawn, a figure code indicating the shape, a figure size, and the like are defined. The converted data information is output to the deflection control circuit 110.

In S302, as the main deflection position correction calculation step, the main deflection calculation unit 114 receives data obtained by converting the drawing data, and based on the drawing data, the center position of the SF in the drawing area of the sample 101 to be drawn. Correct. The main deflection calculation unit 114 is an example of a first correction unit. The center position of the SF is corrected based on the pattern distortion obtained from the positions of the plurality of graphics 302 drawn without correction scattered over substantially the entire drawing area of the dummy substrate 300. Specifically, the correction parameters a ″, b ₁ ″, b ₂ ″,..., D ₃ ″, d ₄ ″ and p ″, q ₁ of the set expressions (12-1) and (12-2) are set. (X _E ″, Y _E ″) is obtained by calculating Expression (12-1) and Expression (12-2) using “, q ₂ ”,..., S ₃ ″, s ₄ ″. As a result, both the global position error and the position error caused by the distortion of the electron optical system are corrected for the SF center position (X _0c , Y _0c ). Then, the main deflection calculation unit 114 outputs a digital deflection amount for deflecting to the center position (X _E ″, Y _E ″) of the calculated corrected SF to the DAC 124. Here, it is preferable to obtain the correction parameters of the equations (12-1) and (12-2) so that the center position (X _E ″, Y _E ″) becomes the digital deflection amount for output to the DAC 124. It is. That is, X _E ″ and Y _E ″ are preferably input values to the deflecting DAC / AMP.

In S306, as a D / A (digital analog) conversion step, the DAC 124 converts the digital deflection amount for deflecting to the calculated SF center position (X _E ″, Y _E ″) into an analog deflection amount.

In S402, as a sub deflection position correction calculation step, the sub deflection calculation unit 112 receives data obtained by converting drawing data, and based on the drawing data, the SF center position (X _1c , Y _{1c) serving as} a correction reference position. ) To an arbitrary position in the SF (x ₀ , y ₀ ) is corrected. The sub deflection operation unit 112 is an example of a second correction unit. The relative distances (x ₀ , y ₀ ) are correction equations (2-1) and (2-2) for correcting the center position (X _0c , Y _0c ) of the SF based on the pattern distortion of the dummy substrate 300. And the center position (X _0c , Y _0c ). Specifically, the correction parameters a ′, b ₁ ′, b ₂ ′,..., D ₃ ′, d ₄ ′ and p ′, q ₁ of the set expressions (11-1) and (11-2) are set. (X _E , Y _E ) is obtained by calculating Expression (11-1) and Expression (11-2) using “, q ₂ ′,..., S ₃ ′, s ₄ ′. Thereby, both the global position error and the position error caused by the distortion of the electron optical system can be corrected with respect to the relative distance (x ₀ , y ₀ ) from the center in the SF to the arbitrary position in the SF. Then, the sub deflection operation unit 112 outputs the digital deflection amount for deflecting to the calculated corrected relative distance (X _E , Y _E ) to the DAC 122. Here, it is preferable to obtain the correction parameters of the expressions (11-1) and (11-2) so that the relative distance (X _E , Y _E ) becomes the digital deflection amount for output to the DAC 122. . That is, X _E and Y _E are preferably input values to the deflecting DAC / AMP.

In S406, as a D / A (digital analog) conversion step, the DAC 122 converts the digital deflection amount for deflecting to the calculated relative distance (X _E , Y _E ) into an analog deflection amount.

In S <b> 502, as a drawing process, the drawing unit 150 deflects the electron beam 200 based on the analog deflection amount for each deflector, and draws a predetermined pattern on the sample 101. The analog deflection amount converted by the DAC 124 is amplified by the amplifier 134 and applied to the main deflector 214 as a main deflection voltage. Then, the main deflector 214 deflects the reference position of the SF in which the electron beam 200 is corrected by the electrostatic action due to the deflection voltage. Thereby, the reference position of the SF is determined. Here, the center position (X _E ″, Y _E ″) is the reference position of the SF. The analog deflection amount converted by the DAC 122 is amplified by the amplifier 132 and applied to the sub deflector 212 as a sub deflection voltage. The sub deflector 212 deflects the electron beam 200 to a position further away from the position deflected by the main deflector 214 by the corrected relative distance by the electrostatic action due to the deflection voltage. Thereby, a desired figure can be drawn. Here, the relative distance (X _E , Y _E ) is a relative distance from the reference position of the SF to an arbitrary position within the SF.

FIG. 5 is a conceptual diagram for explaining the SF correction for the global position error in the first embodiment.
As shown in FIG. 5A, when the pattern 10 is distorted or deflected, first, the position of the center 14 of the SF 12 inside the pattern 10 after drawing is shown in FIG. ) So as to be positioned on a straight line as shown in FIG. Then, the sub-deflection position correction corrects the distortion of the SF 22 itself so that it becomes a square or a rectangle without distortion as shown in FIG. By correcting not only the coordinates (reference position) of the center 14 of each SF 12 but also the arbitrary position coordinates of each SF 12 as in the present embodiment, distortion or deflection inside the SF as shown in FIG. The resulting error can also be eliminated or reduced. Here, by correcting the pattern 10 that is distorted convexly on the left side in the front of the drawing so that SF12a to SF12e are convex on the right side, the SF12a to SF12a to the position without deviation as shown in FIG. The SF 12e can be positioned. As a result, correction can be performed with sufficient accuracy.

  As described above, at the time of sub-deflection, the correction equations (7-1) and (7-2) for correcting the relative distance based on the pattern distortion of the dummy sample 300 and the optical system of the electron beam 200 are used. The relative distance is corrected by using a coefficient obtained by synthesizing the coefficients of the correction formula (9-1) and the correction formula (9-2) for correcting the relative distance error. As a result, both the global position error and the position error caused by the distortion of the electron optical system can be corrected.

  In the above description, what is described as “to part” or “to process” can be configured by a computer-operable program. Or you may make it implement by not only the program used as software but the combination of hardware and software. Alternatively, a combination of hardware and firmware may be used. When configured by a program, the program is recorded on a readable recording medium such as a magnetic disk device, a magnetic tape device, FD, CD, DVD, MO, or ROM.

The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In the above description, the distortion correction of the electron optical system is performed at the same time. However, the present invention is not limited to this. You may provide the process or function corrected separately. For example, it is preferable that the distortion correction of the electron optical system is performed for the corrected position after the global position correction is performed first. Or the reverse is also suitable. Alternatively, although the accuracy is inferior, the case where only the global position correction is performed without correcting the distortion of the electron optical system is not excluded. In these cases, the correction parameters A ′, B ₁ ′, B ₂ ′, C ₁ ′, C ₂ ′, C ₃ ′, D ₁ ′, D in the equations (7-1) and (7-2) are used. ₂ ′, D ₃ ′, D ₄ ′ and P ′, Q ₁ ′, Q ₂ ′, R ₁ ′, R ₂ ′, R ₃ ′, S ₁ ′, S ₂ ′, S ₃ ′, S ₄ ′ and Expressions (7-1) and (7-2) may be set in the sub-deflection calculation unit 112. Similarly, the correction parameters A, B ₁ , B ₂ , C ₁ , C ₂ , C ₃ , D ₁ , D ₂ , D ₃ , D ₄ and P, in the expressions (2-1) and (2-2), Q ₁ , Q ₂ , R ₁ , R ₂ , R ₃ , S ₁ , S ₂ , S ₃ , S ₄ and Expressions (2-1) and (2-2) are set in the main deflection calculation unit 114. Just keep it.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all charged particle beam writing methods and apparatuses that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

10, 11 Pattern 20 Drawing area 12, 22 SF
14, 24 Center 100 Drawing device 101, 340 Sample 102 Electron barrel 103 Drawing chamber 105 XY stage 109 Magnetic disk device 110 Deflection control circuit 112 Sub deflection operation unit 114 Main deflection operation unit 120 Drawing control circuit 122, 124 DAC
130 Laser measuring system 132, 134 Amplifier 150 Drawing unit 160 Control unit 200 Electron beam 201 Electron gun 202 Illumination lens 203, 410 First aperture 204 Projection lens 205 Molding deflector 206, 420 Second aperture 207 Objective lens 209 Reflection Mirror 212 Sub deflector 214 Main deflector 300 Dummy substrate 302 Graphic 330 Electron beam 411 Opening 421 Variable shaping opening 430 Charged particle source

Claims (5)

An irradiation unit for irradiating a charged particle beam;
A stage on which a sample to be drawn is placed;
Scattered over substantially the entire surface of the drawing area of the dummy sample, based on the positions of a plurality of figures are drawn, a first correction unit for correcting the reference position of the small area of the drawing area of the sample to be drawn,
A first deflector for deflecting the charged particle beam based on a corrected reference position in which the reference position is corrected while the stage moves ;
Dependent as before Symbol reference position first coefficient correction formula for correcting the said reference position, second correction for correcting the relative distance from the correction reference position to any position of the small area A second correction unit that corrects a relative distance from the correction reference position to an arbitrary position in the small region using a coefficient of an equation;
A second deflector for further deflecting the charged particle beam from a position deflected by the first deflector based on the corrected relative distance;
A charged particle beam drawing apparatus comprising: The charged particle beam drawing apparatus further includes:
A mirror that is arranged on the stage along the drawing area of the sample with a length equal to or longer than the drawing area, and that reflects laser light;
A measurement unit that irradiates the laser beam and receives the laser beam reflected from the mirror, and measures the position of the stage based on the received laser beam;
The charged particle beam drawing apparatus according to claim 1, further comprising:   The charged particle beam drawing apparatus according to claim 1, wherein the second correction unit further corrects an error in the relative distance caused by the optical system of the charged particle beam.   The second correction unit corrects an error of the relative distance caused by the coefficient of the correction formula for correcting the relative distance based on the pattern distortion of the dummy sample and the optical system of the charged particle beam. The charged particle beam drawing apparatus according to claim 1, wherein the relative distance is corrected using a coefficient obtained by combining a coefficient of a correction formula. In a charged particle beam writing method for drawing a predetermined pattern on a sample by deflecting a charged particle beam using first and second deflectors,
Scattered over substantially the entire surface of the drawing area of the dummy sample, based on the positions of a plurality of figures drawn, corrects the reference position of the small area to be deflected by the first deflector drawing area of the sample to be drawn And a process of
Deflecting the charged particle beam based on a corrected reference position in which the reference position is corrected by the first deflector while the stage is moving;
Dependent as before Symbol reference position first coefficient correction formula for correcting the said reference position, second correction for correcting the relative distance from the correction reference position to any position of the small area Correcting a relative distance deflected by the second deflector from the corrected reference position where the reference position is corrected to an arbitrary position in the small region, using a coefficient of the equation;
Further deflecting the charged particle beam from the position deflected by the first deflector based on the corrected relative distance by the second deflector;
A charged particle beam drawing method comprising:

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