JP3369835B2 - Shape evaluation method of shaping aperture in charged beam writing apparatus and rotation adjustment method of shaping aperture - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a desired beam shape by passing a charged beam emitted from an electron gun through a shaping aperture, and irradiates a sample with the shaped charged beam to perform drawing. The present invention relates to a method of evaluating the shape of a shaping aperture and a method of adjusting the rotation of the shaping aperture in a charged beam drawing apparatus.

[0002]

2. Description of the Related Art In a charged beam drawing apparatus for drawing directly on a semiconductor wafer or a photomask used for semiconductor manufacturing, in order to form a charged beam into a desired shape,
Usually, the first shaping aperture is arranged on the side closer to the electron gun, and the second shaping aperture is arranged on the side closer to the sample.

In such a charged beam drawing apparatus, evaluation of the shape of the above two shaping apertures and adjustment of the rotation angle of the shaping aperture are performed.

FIG. 22A shows an example of the first shaping aperture, and FIG. 22B shows an example of the second shaping aperture. The aperture shape of the first shaping aperture is usually rectangular. Although various shapes of apertures in the second shaping aperture are considered, here, a key type in which a small rectangle and a large rectangle are combined is shown.

In the following, each straight line portion of the rectangular aperture of the first shaping aperture, that is, the straight line edge is denoted by e1 and e.
2, e3 and e4. Further, the three straight line portions formed by the small rectangles of the second shaping aperture, that is, the straight line edges are defined as eU, eL, and eD, and the three diagonal line portions formed by the large rectangles, that is, the diagonal line edges are formed by A, B, and C. , D
In addition, the corner sandwiched between the diagonal edges A and D is C1, and the corner sandwiched between the diagonal edges B and C is C.
2. The corner sandwiched between the diagonal edges C and D is C3.

By using two shaping apertures having such an aperture shape in combination, the charged beam can be shaped into a rectangle or a triangle.

For example, the edge e of the first shaping aperture
By combining 1, e2, e3, e4 with the edges eU, eL, eD of the second shaping aperture, the charged beam can be shaped into a rectangle, and the corner of the first shaping aperture and the second shaping aperture can be formed. The charged beam can be shaped into a triangle by combining the diagonal edges A, B, C, and D.

By the way, the above-mentioned forming aperture is formed with high precision, but since its size is a fine shape of about several tens μm to several hundreds μm, it can be produced with high precision in the manufacturing process. difficult. Therefore, the aperture shape is evaluated.

For example, in the case of evaluating the edge angle α of the diagonal edges A to D of the second shaping aperture (only the edge angle for one diagonal edge A is shown in FIG. 22B), conventionally, a triangular pattern is actually used. Was drawn on the resist pattern, and the shape of the resist pattern after drawing was observed using an optical microscope or a scanning electron microscope to obtain the edge angle α.

Further, based on the evaluation result, the rotation adjustment of the second shaping aperture is performed so that a triangular drawing pattern having a desired angle can be obtained.

However, in the above-mentioned conventional method, since the steps of drawing and developing are included, it takes a long time for the evaluation, and accordingly, it takes time for feedback to the adjustment of the rotation angle of the aperture, and the adjustment takes a short time. There is a problem that you cannot do it. Further, since the influence of these steps is mixed, there is also a problem that the accuracy of adjustment is lowered.

Furthermore, it is also necessary to evaluate the roughness (irregularities: shape error) of the diagonal edges A to D of the second shaping aperture.

Conventionally, the roughness is evaluated by observing and taking a photograph using an optical microscope or a scanning electron microscope, as in the case of the edge angle evaluation described above.

However, as described above, the dimension of the second shaping aperture is about several tens of μm to several hundreds of μm, and its roughness is smaller than about 0.1 μm, and the resolution of 0.1 μm is obtained. Therefore, it is necessary to set each microscope to a high magnification.

However, if a high magnification is set, the second
It becomes difficult to observe the shape of the entire shaping aperture. Therefore, if the magnification is set to low, it becomes difficult to observe the uneven shape of the edge of the second shaping aperture with high accuracy.

Moreover, it is difficult to perform a highly accurate quantitative dimension evaluation in the thickness direction of the second shaping aperture because defocusing occurs in each microscope.

Further, since the shaping aperture has a thickness, the innermost convex portion of the aperture is the object of dimensional evaluation, but it was difficult to quantitatively measure the entire shaded portion.

It is also known that when the shaping aperture is irradiated with a charged beam in the drawing apparatus, contamination attaches to the shaping aperture and the shape changes.

Conventionally, when evaluating the shape change amount,
Since the aperture is taken out from the drawing device and observed by a microscope, there is a drawback that the evaluation cannot be performed accurately in a short time.

Further, similarly for the first shaping aperture, it is necessary to quantitatively evaluate the shape evaluation and the roughness at each straight edge, and adjust the rotation of the first shaping aperture based on the evaluation result.

Conventionally, the rotation angle of the first shaping aperture is adjusted by, as shown in FIG. 23, a rectangular charged beam 31 shaped by the first and second shaping apertures onto the backscattered electron detecting particles 32. Scanning is performed, and at this time, the backscattered electron detector 33 detects backscattered electrons to measure the beam profile.

Then, the first shaping aperture is rotated so that the upper distribution of the beam profile appears flat as shown in FIG. 23 (b). That is, as shown in FIGS. 23A and 23C, when a flat beam profile cannot be obtained, the first shaping aperture is rotated to obtain a flat beam profile as shown in FIG. 23B. Adjust the angle so that it can be obtained.

However, the detection signal output from the backscattered electron detector 33 is susceptible to electrical noise, and the reproducibility is poor at a dozen rad. Further, even if there are minute irregularities on the edge of the first shaping aperture, the detection signal is buried in electrical noise, and it is difficult to adjust the rotation in consideration of the irregularities.

[0024]

As described above, the conventional method for evaluating the forming aperture has a problem that the evaluation cannot be performed with high accuracy in a short time.

Further, the conventional method of adjusting the rotation angle of the forming aperture has a problem that the rotation cannot be adjusted with high accuracy in a short time.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a shaping aperture in a charged beam drawing apparatus capable of accurately evaluating the shape of the shaping aperture in a short time. It is to provide a shape evaluation method.

Another object of the present invention is to provide a method of adjusting the shaping aperture in a charged beam drawing apparatus which can adjust the rotation angle of the shaping aperture in a short time and with high accuracy.

[0028]

According to another aspect of the present invention, there is provided a method for evaluating a shape of a shaping aperture in a charged beam drawing apparatus, wherein a charged beam formed by a first shaping aperture having a rectangular shape is projected by a projection lens and has at least a hatched portion. Second
Forming the charged beam by combining an image obtained by deflecting the image formed by the first shaping aperture with a shaping deflector and the shape of the second shaping aperture while forming an image on the shaping aperture. Then, in the charged beam drawing apparatus having a function of forming and irradiating the shaped charged beam on the sample surface with the objective lens, the rectangular corner portion of the first shaping aperture and the hatched portion of the second shaping aperture are formed. The first and second shaping apertures are used to shape a beam, and the corners of the rectangular aperture image of the first shaping aperture are accurately aligned with the reference coordinate system on the sample surface along the hatched portion of the second shaping aperture. The beams of the beams shaped by the first and second shaping apertures are deflected by a fixed amount at a deflection angle θ in the matched shaping deflection coordinate system. Current value is measured and the operation is performed a plurality of times by slightly changing the value of the deflection angle θ, and the deflection angle θ when the beam current value measured at each deflection is constant is set to the second shaping aperture. Is the edge angle α with respect to the reference coordinate system on the sample surface and the forming deflection coordinate system.

In the shape evaluation method of the shaping aperture in the charged beam drawing apparatus according to the second aspect, the charged beam formed by the first shaping aperture having a rectangular shape is projected by the projection lens onto the second shaping aperture having at least a hatched portion. The charged beam is shaped by the combination of the image obtained by deflecting the image formed by the first shaping aperture with the shaping deflector and the shape of the second shaping aperture while forming the image. In a charged beam drawing apparatus having a function of forming and irradiating the formed charged beam on a sample surface with an objective lens, a rectangular corner portion of the first shaping aperture image and a hatched portion of the second shaping aperture are used, The corner portion of the rectangular aperture image of the first shaping aperture is displaced by a certain amount h with respect to the reference of the hatched portion of the second shaping aperture. Beam is shaped by the first and second shaping apertures in this state, and the corner portion of the rectangular aperture image of the first shaping aperture is deflected along the oblique line portion of the second shaping aperture by a certain amount, and the beam is changed each time. The current value is measured, and the measured beam current value I, the beam current density J, and the distance h are used to calculate the unevenness amount δh from the reference of the shaded portion δh = (I / J) ^1/2 -H ... (1) is calculated, and this δh is defined as the roughness in the shaded portion of the second shaping aperture.

In the method for adjusting the rotation of the shaping aperture in the charged beam drawing apparatus according to the third aspect of the invention, the charged beam formed by the first shaping aperture having a rectangular shape is projected onto the second shaping aperture having at least a shaded portion by the projection lens. The charged beam is shaped by the combination of the image obtained by deflecting the image formed by the first shaping aperture with the shaping deflector and the shape of the second shaping aperture while forming the image. In a charged beam drawing apparatus having a function of imaging and irradiating the formed charged beam on a sample surface with an objective lens and a rotation adjusting mechanism of a shaping aperture, a second shaping aperture is used as a reference for an edge of an aperture image of the first shaping aperture. Exposed by a predetermined amount from the reference position of the corner of the second shaping aperture. And step-deflect at a desired deflection angle θ in the shaping deflection coordinate system that is exactly matched to the reference coordinate system on the sample surface, and measure the beam current amount of the charged beam passing through the first and second shaping apertures. By adjusting the rotation angle of the first shaping aperture so that the change in the beam current amount is minimized, the rotation is adjusted to a desired deflection angle θ.

In the shape evaluation method of the shaping aperture in the charged beam drawing apparatus according to the fourth aspect, the charged beam formed by the first shaping aperture having a rectangular shape is projected by the projection lens onto the second shaping aperture having at least a hatched portion. The charged beam is shaped by the combination of the image obtained by deflecting the image formed by the first shaping aperture with the shaping deflector and the shape of the second shaping aperture while forming the image. In a charged beam drawing apparatus having a function of forming and irradiating the formed charged beam on a sample surface with an objective lens, an aperture image edge of the first shaping aperture is moved by a predetermined amount from a reference position of a corner of the second shaping aperture. 2 Molding deflection seat that is exactly aligned with the reference coordinate system of the sample surface while being exposed from the aperture of the molding aperture In the system, the beam current amount I of the charged beam passing through the first and second shaping apertures is measured by step-deflection at a deflection angle that matches the desired edge angle of the first shaping aperture image. From the beam current density J and the shape of the corner of the second shaping aperture, the unevenness amount δh with respect to the reference edge of the first shaping aperture image is calculated from δh = (I / J) ^1/2 −h (2) This δh is defined as the roughness at the edge of the first shaping aperture.

In the shape evaluation method of the shaping aperture in the charged beam drawing apparatus according to the fifth aspect, the charged beam formed by the first shaping aperture having a rectangular shape is projected by the projection lens onto the second shaping aperture having at least a shaded portion. The charged beam is shaped by the combination of the image obtained by deflecting the image formed by the first shaping aperture with the shaping deflector and the shape of the second shaping aperture while forming the image. In a charged beam drawing apparatus having a function of imaging and irradiating the formed charged beam on a sample surface with an objective lens, roughness h at each edge of the rectangular aperture of the first shaping aperture is measured in advance, and the first shaping is performed. The edge of the rectangular aperture image of the aperture is a predetermined amount w from the edge of the rectangular portion of the second shaping aperture. In the shaping deflection coordinate system which is exposed in the aperture direction of the second shaping aperture and is exactly matched with the reference coordinate system of the sample surface at the pitch p, step deflection is performed at a deflection angle that matches a desired second shaping aperture rectangular portion edge, The beam current amount I of the charged beam passing through the first and second shaping apertures is measured, and from the beam current amount I, the beam current density J and the edge roughness of the first shaping aperture, the rectangular portion of the second shaping aperture is measured. The unevenness amount δi with respect to the reference edge of (Where i is the number of deflection steps, which is an arbitrary positive number), and is used as the roughness at the edge of the second shaping aperture.

In the method for adjusting the rotation of the shaping aperture in the charged beam drawing apparatus according to the sixth aspect, the charged beam formed by the first shaping aperture having a rectangular shape is projected by the projection lens onto the second shaping aperture having at least a hatched portion. The charged beam is shaped by the combination of the image obtained by deflecting the image formed by the first shaping aperture with the shaping deflector and the shape of the second shaping aperture while forming the image. In a charged beam drawing apparatus having a function of imaging and irradiating the formed charged beam on a sample surface with an objective lens and having a rotation adjusting mechanism of a shaping aperture, the roughness h at each edge of the rectangular aperture of the first shaping aperture is previously set. The edge of the rectangular aperture image of the first shaping aperture is measured and the second A desired second shaping aperture rectangle in the shaping deflection coordinate system which is exposed in the aperture direction of the second shaping aperture from the edge of the rectangular portion of the shape aperture in the direction of the aperture of the second shaping aperture and is exactly matched with the reference coordinate system of the sample surface at the pitch p. The beam current amount I of the charged beam passing through the first and second shaping apertures is measured by performing the step deflection at a deflection angle that coincides with the partial edge, and the beam current amount I, the beam current density J, and the first shaping aperture are measured. From the edge roughness, the unevenness amount δi with respect to the reference edge of the rectangular portion of the second shaping aperture is calculated. (Where i is the number of deflection steps and is an arbitrary positive number), and is set as the roughness at the edge of the second shaping aperture, and the edge of the second shaping aperture is approximated by a straight line using this roughness, The rotation angle of the first or second shaping aperture is adjusted so that the inclination of the approximated straight line matches the target angle of the reference coordinate system on the sample surface.

In the shape evaluating method of the shaping aperture in the charged beam drawing apparatus according to the seventh aspect, a first shaping aperture including a rectangular drawing aperture and at least one evaluation aperture having a smaller shape than that, a main aperture, and A second shaping aperture including at least one character aperture, wherein the first shaping aperture image is formed on the second shaping aperture by a projection lens, and is deflected by a shaping deflector to form a charged beam. In the beam drawing apparatus, the first
The evaluation aperture image of the shaping aperture is exposed from the reference edge of the second shaping aperture to the main aperture or the character aperture of the second shaping aperture by a predetermined amount, and along the edge of the main aperture or the character aperture of the second shaping aperture. The first
A beam current amount I of the charged beam passing through the first and second shaping apertures is measured by step-deflecting the evaluation aperture image of the shaping aperture with a shaping deflection coordinate system that exactly matches the reference coordinate system on the sample surface. Then, based on the beam current amount I, the beam current density J, and the shape and size of the evaluation aperture, the unevenness amount from the reference edge of the aperture of the second shaping aperture is obtained, and this is determined as the edge of the second shaping aperture. It's called roughness.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, before describing the embodiments of the present invention, the configuration of a charged beam drawing apparatus used for carrying out the method of the present invention will be described with reference to FIG.

A first illumination lens 2, a second illumination lens 3, a first projection lens 4, a second projection lens 5, a reduction lens 6 and an objective lens 7 are provided in the traveling path of the charged beam emitted from the electron gun 1. It is arranged.

On the traveling path of the charged beam, the blanking deflector 8 is provided between the second illumination lens 3 and the first projection lens 4.
Is disposed, the shaping deflector 9 is disposed between the first projection lens 4 and the second projection lens 5, and the objective deflector 10 is disposed at the position of the objective lens 7.

A circular aperture 11 and a first shaping aperture 12 are arranged between the blanking deflector 8 and the first projection lens 4 on the traveling path of the charged beam.
The second shaping aperture 13 is arranged between the projection lens 5 and the reduction lens 6, and further the reduction lens 6 and the objective lens 7 are arranged.
A round aperture 14 is arranged between the two.

Of these, the first shaping aperture 12 has a rectangular aperture shape as shown in FIG. 22 (a), and the second shaping aperture 13 has a rectangular aperture shape as shown in FIG. 22 (b). It has a key-shaped aperture shape.

The sample 15 is placed at the image forming position of the objective lens 7.
Is arranged, and the backscattered electron detector 16 is provided above the sample 15.
And a beam current detector 17 called a Faraday cup is arranged below the sample 15.

Although not shown, the above first and second
An aperture rotating mechanism is provided at each position for adjusting the rotation angle of the shaping apertures 12 and 13, and an aperture XY for moving the first and second shaping apertures 12 and 13 in the horizontal direction. A moving mechanism is provided.

Further, the shaping deflector 11 has a rotation correction function, and the shaping deflection rotation correction function parameter matching the reference coordinate system on the sample surface is previously obtained and stored.

In the charged beam drawing apparatus having such a structure, the charged beam emitted from the electron gun 1, that is, the crossover image, as shown in the crossover imaging system 18, has the first illumination lens 2 and the second illumination. The image is formed five times by the lens 3, the first projection lens 4, the second projection lens 5, and the reduction lens 6, and finally is formed on the main surface of the objective lens 7.

At the same time, the charged beam emitted from the electron gun 1 passes through the first shaping aperture 12 and, thereafter, is deflected by the shaping deflector 9 and passes through the second shaping aperture 13. The first and second shaping apertures 12 and 13 are combined to form an aperture shape.

The first shaping aperture image is the shaping image forming system 1
An image is formed on the second shaping aperture 13 as shown in FIG.
After that, the sample 15 is removed by the reduction lens 6 and the objective lens 7.
An image is formed on the surface.

Next, in the charged beam drawing apparatus having such a configuration, the edge angles α of the diagonal edges A to D (shown in FIG. 22B) of the second shaping aperture 13 are obtained, and the second shaping aperture is obtained. A method according to the first embodiment of the present invention for performing the shape evaluation will be described.

For example, the edge angle α at one diagonal edge A of the second shaping aperture 13 is obtained as follows. First, the shaping deflector 9 is controlled to deflect the first shaping aperture so that one corner of the first shaping aperture image slightly overlaps the diagonal edge A of the second shaping aperture 13 as shown in FIG. That is, at this time,
The corners of the first shaping aperture 12 and the diagonal edges A of the second shaping aperture 13 are used to shape the triangular beam. Next, in this state, the triangular beam is deflected by deflecting the corner of the first shaping aperture image along the oblique edge A of the second shaping aperture at a predetermined deflection angle θ by a constant amount. The beam current detector 17 measures the beam current value. Then, the same operation is performed a plurality of times by changing the value of the deflection angle θ.

In FIGS. 3A to 3C, the deflection angle θ is θ1,
It shows a state in which the triangular beams are sequentially step-deflected by setting θi and θn respectively.

FIG. 4 shows the relationship between the deflection amount X and the beam current value I measured each time when the deflection angle θ is set to various values.

As shown in FIG. 3A, the deflection angle is θ1.
, The area of the triangular beam decreases each time the triangular beam is step-deflected, so that the beam current value I decreases as the deflection amount X increases as shown in FIG. I will do it. Further, as shown in FIG. 3C, when the deflection angle is set to θn, the area of the triangular beam increases each time the triangular beam is step-deflected. The value I increases as the deflection amount X increases.

On the other hand, as shown in FIG. 3B, when the deflection angle is set to θi, the area of the triangular beam does not change even if the triangular beam is step-deflected. As shown in, the beam current value I does not change and is constant. That is, the deflection angle θi at this time is the second
It matches the edge angle α of the diagonal edge A of the shaping aperture 13. Therefore, the deflection angle θi at this time is obtained as the edge angle of the diagonal edge A.

On the other hand, with respect to the remaining diagonal edges B, C and D in the second shaping aperture 13, the edge angle can be obtained by the same method as described above.

When the edge angles of all the diagonal edges have been obtained, the obtained edge angles are compared with a reference edge angle known in advance to evaluate the shape of the second shaping aperture 13. Can be done.

In the conventional method, it took half a day to obtain the edge angle of the diagonal line edge of the second shaping aperture.
According to the method of the above embodiment, this can be done in about several minutes. Further, by making the variation amount Δθ of the deflection angle θ small, highly accurate angle detection can be realized.

Next, in the charged beam drawing apparatus having such a structure, the roughness of each diagonal edge A to D of the second shaping aperture 13 is obtained, and the shape of the second shaping aperture is evaluated. The method of the embodiment will be described.

For example, the roughness at one diagonal edge A of the second shaping aperture 13 is obtained as follows. First, the shaping deflector 9 is controlled so that the reference diagonal edge A of the second shaping aperture 13 is displayed as shown in FIG.
On the other hand, with the corners of the first shaping aperture image being shifted by a certain amount h, the first shaping aperture is deflected so that the diagonal edge A of the second shaping aperture 13 is reached. That is, at this time, the first shaping aperture 12
The triangular beam is shaped by using the corners of and the diagonal edge A of the second shaping aperture 13.

Next, as shown in FIG. 5B, the shaping deflector 9 is scan-controlled to deflect the first shaping aperture image by a predetermined amount along the diagonal edge A of the second shaping aperture. The triangular beam is deflected by, and the beam current value is measured by the beam current detector 17 each time.

By the way, when there is no roughness in the shaded edge portion A, as shown in FIG. 6A, the area of the first shaping aperture image which appears inside the second shaping aperture (aperture side) (scanned triangle). The beam area) is always constant, and the measured beam current value does not change as shown in FIG. 6B and is always constant.

Next, the slanted edge A of the second shaping aperture
The case where there is roughness will be described with reference to FIG.

FIG. 7A shows the vicinity of the diagonal edge A at the position where the roughness is 0. In this case, the corner of the first shaping aperture is deflected from the diagonal edge A by a length h. At this time, the area S of the triangular beam formed by the first and second forming apertures is h ² and the measured current value I is S × J, where J is the beam current density.

FIG. 7B shows a length δ from the reference diagonal edge.
The vicinity of the diagonal edge A at a position where the diagonal edge is recessed by h is shown. At this time, the area S of the triangular beam formed by the first and second forming apertures is (h + δ
h) ² , and assuming that the beam current density is J and the current value measured at this position is I, the above δh is calculated from δh = (I / J) ^1/2 -h (5).

FIG. 7C shows the vicinity of the diagonal edge A at a position where the diagonal edge is convex by a length δh from the reference diagonal edge. At this time, the area S of the triangular beam formed by the first and second forming apertures is (h
−δh) ² , the beam current density is J, and the current value measured at this position is I, the above δh is calculated from δh = − ((I / J) ^1/2 −h) (6) To be done.

FIG. 8 shows that when unevenness of the diagonal edge of the second shaping aperture is continuously present, the first shaping aperture image is deflected from the reference of the diagonal edge to the inside of the second shaping aperture by the length h, and The figure shows the state when scanning along the diagonal edge and the change in the measured beam current value each time. That is, the shot No. There is no unevenness at each position of 1 and 2, and the shot No. There is convex roughness at each of the positions 1 to 3, and the shot No. i + 1
There is concave roughness at each position of i to i-1.

Then, δ at each shot position is calculated from the measured beam current value Ii for each shot.
hi is calculated by δhi = − ((Ii / J) ^1/2 −hi) (7). It can be seen that when δhi> 0, it is concave from the reference line by δhi, and when δhi <0, it is convex from the reference line by δhi.

On the other hand, for the remaining diagonal edges B, C and D in the second shaping aperture 13, the roughness can be obtained by the same method as described above.

When the roughness of all the diagonal edges is obtained, the shape of the second shaping aperture 13 can be evaluated based on the obtained roughness.

The measurement resolution can be increased by reducing the length h in the range of h> δh. Further, the beam current density J is constant in the charged beam drawing apparatus.

Conventionally, in order to obtain the roughness of the diagonal edge of the second shaping aperture and evaluate the shape, there is only a method by microscopic observation, and the aperture has to be taken out of the electron optical lens barrel and evaluated. However, according to the method of the above-described embodiment, the shape can be evaluated without taking it out to the outside of the electron optical lens barrel, and in particular, the change with time due to contamination of the aperture or the like can be quantitatively measured. For example, beam current density J = 20 A / c
m ² , the measurement resolution of the beam current detector 17 is 1 pA
In case of, by making h slightly larger than δh,
It has become possible to detect roughness of 0.01 μm.

Next, a method according to the third embodiment of the present invention for adjusting the rotation angle of the first shaping aperture 12 will be described.

Here, one of the edges e1, e2, e3, e4 of the first shaping aperture 12 is one edge e.
A case where 1 is used as a reference will be described with reference to FIG.

First, the shaping deflector 9 is controlled so that
As shown in (a), the first shaping aperture 12 is deflected while the edge e1 of the first shaping aperture 12 is exposed from the corner C1 of the second shaping aperture image by a certain amount h from the aperture of the second shaping aperture. . That is,
At this time, the edge e1 of the first shaping aperture 12 and the second e
A triangular beam is formed by using the corner C1 of the forming aperture 13. The length h is set to be sufficiently shorter than the length of the edge e1 of the first shaping aperture image, for example, about 1/50 of the length of the edge.

Next, the shaping deflector 9 is scan-controlled,
The first shaping aperture 12 is accurately step-deflected in the X direction, and each time the beam current detector 17 measures the beam current value. The step amount (deflection amount in the X direction) at this time is set to be sufficiently shorter than the length of the edge of the first shaping aperture image, for example, about 1/50 of the length of the edge.

Next, the first shaping aperture 12 is rotated stepwise by the shaping deflector 9, and as shown in FIG. 9B, the rotation angle θ (θ1 to θi to θn) at the edge e1 of the first shaping aperture 12. After making the different, the scan control of the shaping deflector 9 is performed again, and the first shaping aperture 1
2 is accurately step-deflected in the X direction, and the beam current detector 17 measures the beam current value each time. The step rotation amount is determined according to the target rotation adjustment accuracy, but when 1 mrad is set as the adjustment accuracy, the rotation step amount is 1 mrad or less.

Then, the above-described operation is carried out by performing the other edge e2 of the first shaping aperture 12 and the second shaping aperture 1.
3 in combination with the other corner C2 and the other edge e3 of the first shaping aperture 12 and the second shaping aperture 13
The beam current value is measured by the beam current detector 17 each time in combination with the other corner C3. When the measurement is performed using the corner C3 of the second shaping aperture 13, the first shaping aperture 12 is accurately step-deflected in the Y direction.

FIG. 10 shows the relationship between the deflection amounts Ax1, Ax2 and Sy and the beam current value I measured each time when the rotation angle θ is set to various values.

For example, when the beam current value at the edge e1 is accurately step-deflected in the X direction, if the edge e1 does not coincide with the X direction, the first beam passing through the corner C1 of the second shaping aperture 13 is formed. Since the area of the shaping aperture image changes, a different value of beam current is measured each time the step deflection is performed. That is, the larger the rotational deviation amount, the larger the beam current change amount. Therefore, the first shaping aperture 12 is rotationally adjusted so that the amount of change in the beam current is minimized.

By the way, when each edge of the first shaping aperture 12 has roughness, the effect of this roughness affects the measured beam current value. Therefore, the actually measured change in the beam current value is as shown in FIG. That is, in FIG. 11, the first shaping aperture 1 is located at the position P1.
The edge of No. 2 has a concave roughness, and the beam current value is greatly reduced at this position.

In such a case, the beam current value data having a large amount of change is deleted, the remaining beam current value data is linearly approximated, and the first shaping aperture 12 is made to minimize the slope of the approximated straight line. Adjust the rotation of.

Conventionally, the rotation adjustment of the first shaping aperture 12 has been performed based on the result of detecting the beam profile on the sample surface, but it is weak against noise, and the very small beam size of about 1 μm after reduction is used. The measurement reproducibility was poor because the above profile was handled.

On the other hand, in the method using the beam current measurement according to the above embodiment, the influence of noise is less likely to occur, and the image before reduction is handled, and the relative error is small, so that the reproducibility is good, Reproducibility of conventional method is more than 10 mra
For d, a reproducibility of 1 mrad is obtained.

The shape of the second shaping aperture 13 changes with time in the long term (monthly) due to the adhesion of contamination, but the corner C of the second shaping aperture 13 is changed.
Even if the shape is changed by adhering to 1, C2, and C3, the aperture rotation adjusting method according to the present embodiment is not affected by the change over time because the time required for adjustment is as short as several minutes. Can be adjusted.

Next, a method of the fourth embodiment of the present invention for measuring the roughness of each edge of the first shaping aperture 12 and evaluating the shape of the first shaping aperture 12 will be described.

Here, a case of measuring the roughness at one edge e1 of the first shaping aperture 12 will be described as an example. In addition, regarding the edge e1, it is assumed that the rotation adjustment of the first shaping aperture 12 has already been completed by the method described above.

First, the shaping deflector 9 is controlled so that
As shown in (a), the first shaping aperture 12 is deflected while the edge e1 of the first shaping aperture 12 is exposed from the corner C1 of the second shaping aperture image by a certain amount h from the aperture of the second shaping aperture. . That is,
At this time, the edge e1 of the first shaping aperture 12 and the second e
A triangular beam is formed by using the corner C1 of the forming aperture 13.

The length h is set to be sufficiently shorter than the length of the edge e1 of the first shaping aperture image, for example, about 1/50 of the length of the edge.

Next, the shaping deflector 9 is scan-controlled,
The first shaping aperture 12 is accurately step-deflected in the X direction, and each time the beam current detector 17 measures the beam current value. The step amount (deflection amount in the X direction) at this time is set to be sufficiently shorter than the length of the edge of the first shaping aperture image, for example, about 1/50 of the length of the edge.

FIG. 12 shows the edge e of the first shaping aperture.
1 shows the state when the first shaping aperture image is scanned with respect to the corner C1 of the second shaping aperture when there is no roughness in 1, and the change in the measured beam current value each time. As shown in FIG. 12, the first
When the edge e1 of the shaping aperture has no roughness, the change in beam current is constant.

On the other hand, when the edge e1 of the first shaping aperture has unevenness of unevenness, the state when the image of the first shaping aperture is scanned with respect to the corner C1 of the second shaping aperture, and each time, it is measured. The change in beam current value is shown in FIG.

Since the roughness in this case can be obtained by the same method as that described in FIG. 7, the description thereof will be omitted.

On the other hand, for the remaining edges e2 and e3 of the first shaping aperture 13, the roughness can be obtained by the same method as above.

When the roughness of the edges e1e, e2, e3 is obtained, the shape of the first shaping aperture 12 can be evaluated based on the obtained roughness.

Conventionally, the roughness of the edge of the first shaping aperture has only been evaluated by a microscope, and the aperture has to be taken out of the electron optical lens barrel and evaluated. However, according to the method of the above-described embodiment, the shape can be evaluated without taking it out to the outside of the electron optical lens barrel, and in particular, the change with time due to contamination of the aperture or the like can be quantitatively measured.

Next, the fifth embodiment of the present invention for evaluating the shape of the second shaping aperture 13 by measuring the roughness at the three straight edges eU, eL and eD formed by the small rectangle of the second shaping aperture 13. The method of this form will be described.

First, the case of measuring the roughness at one edge eD of the second shaping aperture 12 will be described.

As shown in FIG. 14A, when the roughness of the edge eD of the second shaping aperture 13 is measured,
The edge e2 of the first shaping aperture image is changed from the edge eD to +
A small amount of light is emitted in the Y direction, and step deflection is performed in the + X direction. Here, the X and Y directions are molding deflection coordinates that coincide with the reference coordinate system on the sample surface. In addition, the edge e2 of the first shaping aperture image for the edge eL and the edge e4 of the first shaping aperture image for the edge eU are step-deflected as shown in FIG. 14B or 14C. Measure the beam current.

Next, taking the edge eD as an example, the method of measuring the edge roughness will be described with reference to FIG. First, the roughness at each of the edges e1 to e4 of the first shaping aperture 12 is measured in advance by the method according to the fourth embodiment. The roughness of the edge e2 measured in this way is hi (i is a subscript for each step deflection pitch p) as shown in FIG. In addition, the second shaping aperture 1
The edge roughness of the edge eD of No. 3 is set to δi as shown in FIG. At this time, the edge e2 is changed to the edge eD
The area Si of the figure formed by the edge e2, the edge e4, and the edge eD, which is deflected in the + Y direction by the length w from, is Si = Ii / J ... (Ii = Ji) 8) is given in. On the other hand, if the area Si uses hi and δi, Given in. From equations (8) and (9) above, the edge eD
The roughness δi of However, when i = 0, it can be obtained by δ0 = w + h0−I0 / J / p (11). For example, the length of the edge eD is 5
0 μm, p = 1 μm, w = 0.5 μm, J = 0.01 A
/ Cm ² and Ii and hi have the following values, δi is as shown in Table 1 below.

[0097]

[Table 1]

The edge roughness can be measured in the same manner for the edges e2L and eU.
The shape of the second shaping aperture 13 can be evaluated based on the measurement result.

Conventionally, the shape of the second shaping aperture can only be evaluated by observation with a microscope, and the aperture must be taken out of the electron optical lens barrel and evaluated. However, according to the method of the above-described embodiment, a mirror is used. The shape of the second shaping aperture can be evaluated without taking out the aperture to the outside of the cylinder.

Next, a method of adjusting the rotation of the second shaping aperture will be described. FIG. 16 shows an example of the shape of the small rectangular portion of the second shaping aperture obtained by the above method. When trying to align the edge eD with the reference coordinate system XY,
Data of the edge eD is approximated by a straight line (Y = aX + b),
Find the slope a. Next, the second shaping aperture 13 is rotated so that the inclination a approaches 0, the edge eD is measured and calculated again, and the inclination a is further approached to 0.

On the other hand, when it is desired to match the edge eL,
The inclination a is driven in such a manner that the inclination a becomes large and approaches 0 when it is desired to match the edge eU.

Next, a method of another embodiment of the present invention for measuring the roughness of the second shaping aperture 13 and evaluating the shape will be described.

In each of the embodiments described above, FIG.
As shown in (a) and (b), the first shaping aperture 12
Has a rectangular aperture shape, and the second shaping aperture 1
No. 3 has been described as having a key-shaped aperture shape.

However, as the second shaping aperture, as shown in FIG.
As shown in FIG. 7B, in addition to the key-shaped aperture (main aperture) 20 for forming rectangular and triangular beams, a plurality of character apertures 21 having various shapes can be used. For example, the plurality of character apertures 21 includes a first character aperture 21a in which two rectangles having different thicknesses are combined, as shown in the lower left and lower right of the figure.

Further, as the first shaping aperture, as shown in FIG.
As shown in FIG. 7B, in addition to the rectangular aperture 22 used for drawing, a plurality of evaluation apertures 23 for evaluating the second shaping apertures having various shapes can be used. The shape of these evaluation apertures 23 is smaller than that of the rectangular aperture 22, and is rectangular, round, triangular, or the like.

By using the plurality of character apertures 21 in the second shaping aperture in combination with the rectangular apertures 22 of the first shaping aperture, a charged beam shaped in a shape corresponding to each of the character apertures 21 is formed on the sample. Can be irradiated.

Next, the method of the sixth embodiment in which the shape evaluation of the key-shaped aperture 20 of the second shaping aperture is performed by using the small rectangular aperture 23 of the first shaping aperture will be described.

First, as shown in FIG. 18A, the rectangular aperture 23 of the first shaping aperture is moved on the optical axis by using the aperture XY moving mechanism. Next, the rectangular aperture 23 is deflected to the edge eD (reference edge) of the second shaping aperture shown in FIG. 18B to expose the image to the second shaping aperture by the length h. Then, along the edge eD, the first shaping aperture image is step-deflected by the dimension d of the rectangular aperture 23 itself, and the beam current detector 17 measures the beam current value each time.

FIG. 18C shows that when the unevenness of the edge eD of the second shaping aperture is continuously present, the first shaping aperture image is deflected by the length h from the reference of the edge eD to the inside of the first shaping aperture. Then, the state at the time of scanning along the edge eD and the change in the measured beam current value at each time are shown.

In this case, δ at each shot position is determined by the measured beam current value I for each shot.
h is calculated | required by (delta) h = h-I / J / d ... (12). Then, it can be seen that the second aperture is convex when δh> 0, and concave when δh <0.

On the other hand, for the remaining edges eU and eL in the second shaping aperture 13, the roughness can be obtained by the same method as described above.

Next, with the rectangular aperture 23 of the first shaping aperture being moved on the optical axis using the aperture XY moving mechanism, as shown in FIG. 19, a diagonal edge A (reference edge) of the second shaping aperture is formed. ) With a rectangular aperture 23
To expose the image to the second shaping aperture by a length h. Then, along the edge A, the first shaping aperture image is step-deflected by a predetermined amount, and the beam current detector 17 measures the beam current value each time.

In this case, δ at each shot position is determined by the measured beam current value I for each shot.
h is calculated | required by (delta) h = (I / J) ¹ / ^2- h ... (13). Then, it can be seen that the second aperture is convex when δh> 0, and concave when δh <0.

On the other hand, for the remaining diagonal edges B, C and D in the second shaping aperture 13, the roughness can be obtained by the same method as described above.

When the roughness of all the edges has been obtained, the shape of the second shaping aperture 13 can be evaluated based on the obtained roughness.

Next, the method of the seventh embodiment in which the shape evaluation of the key-shaped aperture 20 of the second shaping aperture is performed using the small round aperture 23 of the first shaping aperture will be described.

First, as shown in FIG. 20A, the circular aperture 23 of the first shaping aperture is moved on the optical axis by using the aperture XY moving mechanism. Next, a predetermined edge (reference edge) of the second shaping aperture shown in FIG.
The circular aperture 23 is deflected to expose the image to the second shaping aperture by the length h. Then, along the edge, the first shaping aperture image is step-deflected by 2r (r is a radius) by the diameter of the circular aperture 23, and the beam current detector 17 measures the beam current value each time.

In this case, δ at each shot position is determined by the measured beam current value I for each shot.
h is, (1) I / J ≦ πr 2/2 if the (convex) δh = r {1- (sin (I / J / r 2) 2} 1/2 ... (14) (2) I / J > pi] r for ^2/2 (concave) δh = r-r {1 -sin (I / J / r 2) 2} given by ^1/2 (15).

With respect to the remaining edges of the second shaping aperture 13, the roughness can be obtained by the same method as described above.

When the second shaping aperture shown in FIG. 17A is used, the shape of each of the plurality of character apertures 21 provided in the second shaping aperture can be evaluated. it can. For example, in the case of evaluating the shape of the first character aperture 21a among the plurality of character apertures 21 provided in the second shaping aperture, as shown in FIG. 21, a circle provided in the first shaping aperture is used. It can be measured by step-deflecting by 2r (r is a radius) by the diameter of the circular aperture 23 and measuring the beam current value by the beam current detector 17 each time.

[0121]

As described above, according to the method of evaluating the shape of the shaping aperture in the charged beam drawing apparatus of the present invention, the shape of the shaping aperture can be evaluated in a short time and with high accuracy.

Further, according to the adjusting method of the shaping aperture in the charged beam drawing apparatus of the present invention, the rotation angle of the shaping aperture can be adjusted in a short time and with high accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a charged beam drawing apparatus used when carrying out the method of the present invention.

FIG. 2 is a view for explaining the method of evaluating the shape of the second shaping aperture according to the first embodiment of the present invention.

FIG. 3 is a view for explaining a shape evaluation method for the second shaping aperture according to the first embodiment.

FIG. 4 is a diagram for explaining a shape evaluation method for the second shaping aperture according to the first embodiment.

FIG. 5 is a view for explaining the method of evaluating the shape of the second shaping aperture according to the second embodiment of the present invention.

FIG. 6 is a diagram for explaining a shape evaluation method for the second shaping aperture according to the second embodiment of the present invention.

FIG. 7 is a diagram for explaining a shape evaluation method for the second shaping aperture according to the second embodiment of the present invention.

FIG. 8 is a view for explaining the method of evaluating the shape of the second shaping aperture according to the second embodiment of the present invention.

FIG. 9 is a view for explaining a rotation adjusting method for the first molding aperture according to the third embodiment of the present invention.

FIG. 10 is a characteristic diagram showing the beam current value I measured by the method according to the third embodiment together with the deflection amount.

FIG. 11 is a characteristic diagram showing a change in beam current value actually measured by the method according to the third embodiment.

FIG. 12 is a view for explaining the method of evaluating the shape of the first shaping aperture according to the fourth embodiment of the present invention.

FIG. 13 is a view for explaining the shape evaluation method for the first shaping aperture according to the fourth embodiment of the present invention.

FIG. 14 is a view for explaining the shape evaluation method for the second shaping aperture according to the fifth embodiment of the present invention.

FIG. 15 is a view for explaining the shape evaluation method for the second shaping aperture according to the fifth embodiment of the present invention.

FIG. 16 is a view for explaining a rotation adjusting method for the second shaping aperture according to the fifth embodiment of the present invention.

FIG. 17 is a view showing first and second shaping apertures used in the method of the present invention.

FIG. 18 is a diagram for explaining the shape evaluation of the second shaping aperture according to the sixth embodiment of the present invention.

FIG. 19 is a view for explaining shape evaluation of the second shaping aperture according to the sixth embodiment of the present invention.

FIG. 20 is a view for explaining shape evaluation of the second shaping aperture according to the seventh embodiment of the present invention.

FIG. 21 is a diagram for explaining the shape evaluation of the second shaping aperture according to the seventh embodiment of the present invention.

FIG. 22 shows another first and second shaping aperture used in the method of the present invention and the conventional method.

FIG. 23 is a view for explaining a conventional method for adjusting the rotation angle of the first shaping aperture.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron gun, 2 ... 1st illumination lens, 3 ... 2nd illumination lens, 4 ... 1st projection lens, 5 ... 2nd projection lens, 6 ... Reduction lens, 7 ... Objective lens, 8 ... Blanking deflector,
9 ... Shaping deflector, 10 ... Objective deflector, 11 ... Round aperture, 12 ... First shaping aperture, 13 ... Second shaping aperture, 14 ... Round aperture, 15 ... Sample, 16 ... Reflection electron detector, 17 … Beam current detector (Faraday cup).

Claims (7)

(57) [Claims] 1. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a shaded portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In a charged beam drawing apparatus having a function, a beam is shaped by the first and second shaping apertures using a rectangular corner portion of the first shaping aperture and a hatched portion of the second shaping aperture, and the second shaping is performed. A shaping deflector in which the corners of the rectangular aperture image of the first shaping aperture are exactly aligned with the reference coordinate system on the sample surface along the oblique line portion of the aperture. The beam current value of the beam shaped by the first and second shaping apertures is measured by deflecting the deflection angle θ in the system by a constant amount, and the operation is performed a plurality of times by slightly changing the value of the deflection angle θ. The deflection angle θ at which the beam current value measured each time the beam is deflected is constant is defined as the edge angle α with respect to the reference coordinate system and the shaping deflection coordinate system on the sample surface of the shaded portion of the second shaping aperture. A method for evaluating the shape of a shaping aperture in a charged beam drawing apparatus, comprising: 2. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a hatched portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In a charged beam drawing apparatus having a function, a rectangular corner of the first shaping aperture image and a shaded portion of the second shaping aperture are used, and the first shaping aperture is used with respect to a reference of a shaded portion of the second shaping aperture. Beam is shaped by the first and second shaping apertures while the corner portion of the rectangular aperture image is shifted by a certain amount h, and the second shaping is performed. The beam current value is measured each time by deflecting the corner portion of the rectangular aperture image of the first shaping aperture by a constant amount along the oblique line portion of the aperture, and the measured beam current value I, beam current density J, and Charged beam drawing characterized in that an unevenness amount δh from a reference of the shaded portion is calculated using the distance h and the shape of the corner portion, and this δh is defined as roughness in the shaded portion of the second shaping aperture. Shape evaluation method of forming aperture in apparatus. 3. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a hatched portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In a charged beam drawing apparatus having a function and a rotation adjusting mechanism of a shaping aperture, a reference of an aperture image edge of the first shaping aperture is a predetermined amount from a reference position of a corner of the second shaping aperture and an aperture of the second shaping aperture. The desired deviation in the forming deflection coordinate system, which is exactly exposed to the reference coordinate system on the sample surface. The beam current amount of the charged beam passing through the first and second shaping apertures is measured by step deflection at an angle θ, and the rotation angle of the first shaping aperture is adjusted so that the change in the beam current amount is minimized. A rotation adjusting method of the first shaping aperture in the charged beam drawing apparatus, wherein the rotation adjustment is performed to a desired deflection angle θ. 4. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a hatched portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In a charged beam drawing apparatus having a function, a reference coordinate of a sample surface in a state where an aperture image edge of the first shaping aperture is exposed from a reference position of a corner of the second shaping aperture by a predetermined amount from the aperture of the second shaping aperture. In the shaping deflection coordinate system that is exactly matched to the system, the deflection angle is adjusted to match the edge angle of the desired first shaping aperture image. Up, and the beam current amount I of the charged beam passing through the first and second shaping apertures is measured. From the beam current amount I, the beam current density J, and the shape of the corner of the second shaping aperture, A method of evaluating the shape of a shaping aperture in a charged beam drawing apparatus, characterized in that an unevenness amount δh with respect to a reference edge of a first shaping aperture image is calculated, and this δh is used as roughness at the edge of the first shaping aperture. 5. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a hatched portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In the charged beam drawing apparatus having a function, the roughness h at each edge of the rectangular aperture of the first shaping aperture is measured in advance, and the edge of the rectangular aperture image of the first shaping aperture is set to the rectangular portion of the second shaping aperture. A predetermined amount w from the edge of the second molding aperture in the aperture direction of the second shaping aperture, and the reference seat on the sample surface at the pitch p. The beam current amount I of the charged beam passing through the first and second shaping apertures is step-deflected at a deflection angle that coincides with a desired second shaping aperture rectangular portion edge in the shaping deflection coordinate system that exactly matches the system. Measure
From the beam current amount I, the beam current density J, and the edge roughness of the first shaping aperture, the amount of unevenness with respect to the reference edge of the rectangular portion of the second shaping aperture is calculated to obtain the roughness at the edge of the second shaping aperture. A method for evaluating the shape of a shaping aperture in a charged beam drawing apparatus, comprising: 6. A charged beam formed by a first shaping aperture having a rectangular shape is imaged by a projection lens on a second shaping aperture having at least a hatched portion, and an image formed by the first shaping aperture is formed. The charged beam is shaped by the combination of the image obtained by deflecting by the shaping deflector and the shape of the second shaping aperture, and the shaped charged beam is imaged and irradiated on the sample surface by the objective lens. In a charged beam drawing apparatus having a function and a rotation adjusting mechanism of a shaping aperture, a roughness h at each edge of the rectangular aperture of the first shaping aperture is measured in advance, and the edge of the rectangular aperture image of the first shaping aperture is measured. Is the aperture of the second shaping aperture by a predetermined amount w from the edge of the rectangular portion of the second shaping aperture. In the shaping coordinate system which is exposed in the vertical direction and is exactly matched with the reference coordinate system of the sample surface at the pitch p, step deflection is performed at a deflection angle that matches a desired second shaping aperture rectangular portion edge, 2 Measure the beam current amount I of the charged beam passing through the shaping aperture,
From the beam current amount I, the beam current density J, and the edge roughness of the first shaping aperture, the unevenness amount with respect to the reference edge of the rectangular portion of the second shaping aperture is calculated as the roughness at the edge of the second shaping aperture, Using this roughness, the edge of the second shaping aperture is approximated with a straight line, and the first straight line is adjusted so that the inclination of the approximated straight line matches the target angle of the reference coordinate system on the sample surface.
Alternatively, the rotation adjusting method of the second shaping aperture in the charged beam drawing apparatus is characterized in that the rotation angle of the second shaping aperture is adjusted. 7. A first shaping aperture including a rectangular drawing aperture and at least one evaluation aperture having a smaller shape than that, a second shaping aperture including a main aperture and at least one character aperture, and In a charged beam drawing apparatus for forming a charged beam by forming a first shaping aperture image on a second shaping aperture with a projection lens and deflecting the beam with a shaping deflector, an evaluation aperture image of the first shaping aperture is obtained. A predetermined amount from the reference edge of the second shaping aperture to the main aperture or character aperture of the second shaping aperture, and for evaluating the first shaping aperture along the edge of the main aperture or character aperture of the second shaping aperture. Sample aperture image The beam current amount I of the charged beam passing through the first and second shaping apertures is measured by performing step deflection in the shaping deflection coordinate system that exactly matches the above reference coordinate system. A charged beam, wherein an unevenness amount from the reference edge of the aperture of the second shaping aperture is obtained from the density J and the shape and size of the evaluation aperture, and is used as the edge roughness of the second shaping aperture. Shape evaluation method of shaping aperture in drawing apparatus.