JPS6312347B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an automatic aberration compensation deflection device that deflects a narrowly focused charged beam onto a sample surface and at the same time automatically compensates for aberrations and focal shifts caused by the deflection. It is.

In general, when a charged beam (hereinafter simply referred to as a beam) is focused onto a sample surface using a magnetic field type or electrostatic type lens and then deflected using a deflector, the spherical aberration of the lens and the deflected beam are Due to the resulting deflection aberration and focal shift, the beam cannot be focused on one point. For this reason, in devices such as electron beam exposure devices and scanning electron microscopes that scan a predetermined range on the sample surface with a narrowly focused beam, in order to compensate for the aforementioned aberrations, a focusing lens and a The amount of spherical aberration is reduced by shortening the distance between the A method has been proposed to compensate for defocus by subtracting a focus compensation current from the lens current.

However, the deflector of the electron beam exposure apparatus is
In order to deflect the beam two-dimensionally, two polarizers, an X-direction polarizer and a Y-direction polarizer, are placed between the focusing lens and the sample surface. As a result, the distance between the focusing lens and the sample surface is cannot be made shorter, and there is a limit to the reduction of the amount of spherical aberration. Furthermore, since the stigmator is placed on the opposite side of the focusing lens from the polarizer, an astigmatism compensation current or voltage is supplied to the stigmator, taking into account the rotation angle of the beam due to the beam passing through the focusing lens. It required control, and operation was extremely troublesome.

In addition, as a method different from the above method,
As disclosed in Publication No. 21136, there is also a method of simultaneously applying deflection in the X and Y directions using one deflector, but this method does not take into account compensation for third-order astigmatism. Therefore, the aberration caused by the deflection is larger than the method described above in which the beam deflection in the X direction and the Y direction is performed using separate deflectors, making it impossible to improve the resolution and making it impractical.

This invention was made to solve the above-mentioned problems, and is a deflector that uses at least eight electrodes or magnetic poles arranged symmetrically with respect to the optical axis in the X direction and the Y direction. A lens that can simultaneously deflect the beam is used, thereby shortening the distance between the focusing lens and the sample surface, reducing the amount of spherical aberration of the focusing lens, and reducing the distortion caused by deflection. The second-order and third-order astigmatism can be calculated by adding the distortion aberration and the deflection voltage or current supplied to the deflector without using a stigmator.
compensation by superimposing a compensation voltage or current for compensating for second- and third-order astigmatism and supplying it to each electrode or magnetic pole of the deflector, thus taking into account the rotation angle of the beam. In addition, it is possible to compensate for distortion aberrations that have not been considered in the past.Furthermore, the shift of the focal point caused by deflection can be corrected by applying a compensation current or voltage to the focusing lens proportional to the square of the amount of beam deflection. It is characterized in that it compensates by supplying

The present invention will be described by way of examples with reference to the drawings.

Figure 1 is a schematic diagram of the electron beam deflection device, Figure 2 is a schematic diagram of the electron beam deflection device;
The figure is a block diagram of an embodiment of the invention in which an electrostatic deflector is used as the deflector, and FIG. 3 is a block diagram of an embodiment of the invention in which a magnetic field deflector is used as the deflector. It is.

In FIG. 1, 1 is a magnetic field type electron lens for beam focusing, and 2 is arranged symmetrically with respect to the optical axis 4'.
Beam 4, consisting of 8 electrodes or magnetic poles
a deflector that two-dimensionally deflects the sample, and 3 is a sample surface.

The electron lens 1 is supplied with a constant current from a lens power supply (not shown) so that the beam 4 becomes the least circle of confusion caused by spherical aberration on the sample surface 3 when it is not deflected.
Supplied from. Note that the radius of the circle of least confusion is given by 1/4C _s ·ω ³ . However, C _s is the spherical aberration coefficient of the lens, and ω is the beam aperture angle. Actually, a compensating electronic lens is separately added to the electronic lens 1 to compensate for the focal shift (ΔZ) using a focal compensation current supplied from the focal compensation circuit 7 or 13 shown in FIG. 2 or 3. ing.

The deflector 2 has eight electrodes or magnetic poles having a length (l) along the optical axis 4' and a distance (r ₀ ) from the optical axis 4'.
In the case of the electrostatic deflector 11 shown in FIG.
±ΔΦ _x , ± from the deflection voltage power supply 6 to each electrode A to H
Voltages ψ ₁ , ψ ₂ , ψ ₃ that are obtained by superimposing an aberration compensation voltage that changes depending on the amount of beam deflection (X _s , Y _s ) on ΔΦ _y
...ψ ₈ is applied respectively. These voltages are generated from aberration compensation circuits 8, 9, and 10 in FIG.

On the other hand, in the case of the magnetic field type deflector 17 shown in FIG.
Currents I ₁ , I ₂ , I 3 are obtained by superimposing aberration compensation currents generated from the aberration compensation circuits 14, 15, and 16 on I _x and _± I _y .
are supplied respectively.

Next, the principle of compensating the aberration of the deflected beam by the above-mentioned apparatus will be explained.

First, regarding the aberration of the deflected beam, in the above device, the focus compensation circuit 7 or 13 and the aberration compensation circuit 8, 9, 10 or 14, 1
5 and 16 are not activated, the simply deflected beam 5 is not focused to a single point on the sample surface 3 due to aberrations, and becomes a beam spot with a size Δu expressed by the following equation.

Δu=D−Mωe ^ix +Ne ⁱ² 〓 ²・ωe ^ix +Aω ₂ +Bω ² e ^2ix
+Ce ⁱ³ 〓 ³ ·ω ² e _-i2x −C _s ω ³ e ^ix (1) Each component of the above-mentioned aberration will be explained in more detail below with reference to equation (1) and FIG. 4. Furthermore, (1)
In the formula, ωe ^ix represents the beam aperture angle.

D in the first term of equation (1) represents a distortion aberration of the deflected beam, and is an aberration that causes the deflection position of the beam to shift in proportion to the cube of the deflection angle α (see FIG. 1). Therefore, even if the beam is scanned over the sample surface to form a square pattern as shown in FIG. 4a, the pattern will be distorted into a pincushion or barrel shape as shown in FIG. 4b.

M in the second term of equation (1) represents an aberration in which the focus of the deflected beam shifts in proportion to the doubling of the deflection angle α.
Therefore, it is an aberration that can be removed by adjusting the strength of the focusing lens.

Ne ⁱ² 〓 ²・ωe ^-ix in the third term of equation (1) is second-order astigmatism, and for example, as shown in Figure 4c, it is an aberration in which the pattern of the deflected beam cross section becomes elliptical. It is.

Aω ² +Bω ² e ^2ix in the fourth and fifth terms of equation (1) are:
This represents comatic aberration, and is one of the reasons why the beam cannot be converged to one point. However, the deflection angle α is
Up to about 0.05 rad (radian) is sufficient, so
The amount of blur caused by this is small, about 0.02 μm at most, and is hardly a problem in practice.

Ce ⁱ³ 〓 ³・ω ² e ^-i2x in the sixth term of equation (1) is third-order astigmatism, which is caused by the fact that the cross-sectional pattern of the deflected beam is triangular, as shown in Figure 4d, for example. This is an aberration.

C _s ω ³ e ^ix in the seventh term of equation (1) represents the spherical aberration caused by the focusing lens, and its coefficient C _s shortens the distance between the focusing lens and the focusing surface (sample surface). It can be made as small as possible. However, it is impossible in principle to completely eliminate this aberration. Figure 4e shows an example of the cross section of the deflected beam blurred by this spherical aberration.
Shown below.

Above, we have explained each component of aberration that causes the deflected beam not to focus on one point, but as mentioned above, in reality, distortion aberration excluding coma, secondary and tertiary astigmatism, and spherical aberration , focus shift has become a problem, and in particular, these are the main causes that hinder processing with submicron precision in electron beam exposure equipment.

This invention compensates for the various aberrations mentioned above, and the distortion aberration D is an aberration in which the deflection position (X _s , Y _s ) of the beam on the sample surface deviates from the ideal deflection position, as described above. Therefore, the deflection voltage or current that causes this deflection position shift is the original deflection voltage ±ΔΦ _x , ±ΔΦ _y or deflection current ±I _x , ±
This distortion aberration can be compensated by subtracting it from I _y or supplying it to the deflector in addition to it. This distortion aberration compensation deflection voltage ±ΔΦ _xc , ±ΔΦ _yc or compensation deflection current ±I _xc , ±
I _yc is generated from the distortion aberration compensation circuit 8 of FIG. 2 or the compensation circuit 14 of FIG. 3, respectively, and is given by the following equation.

±ΔΦ _xc = ±[ΔΦ _x +bΔΦ _x √ ² _x + ² _y +c
(ΔΦ ² _x + ΔΦ ² _y ) ΔΦ _x + dΔΦ _x ] ±ΔΦ _yc = ± [ΔΦ _y +bΔΦ _y √ ² _x + ² _y +c
(ΔΦ ² _x + ΔΦ ² _y ) ΔΦ _y + dΔΦ _y 〕……(2) ±I _xc = ± [I _x ＋b _n I _y √ ² _x ＋ ² _y ＋c _n (I ² _x + I ² _y ) I
_x + d _n I _x ] ±I _yc = ± [I _y −b _n I _x √ ² _x + ² _y +c _n (I ² _x + I ² _y )I
_y + d _n I _y ]...(3) In equations (2) and (3) above, b, c, and d are coefficients of the distortion aberration compensation deflection voltage, and b _n , c _n , and d _n are distortion aberration compensation coefficients. is the coefficient of deflection current.

Note that +ΔΦ _xc is applied to electrodes A and B in the electrostatic deflector 11 in FIG. 2, and -ΔΦ _xc is applied to E and F, +
By applying Φ _yc to C and D, and -ΔΦ _yc to G and H, respectively, the beam is deflected in any direction without distortion. Similarly, in the _magnetic field deflector ₁₇ in _{FIG .}
H to compensate for distortion aberrations.

The focus shift M caused by the deflection is compensated for by supplying a focus compensation current to the focus compensation electron lens to compensate for the focus shift. This focal point compensation current is generated from the focal point compensation circuit 7 in Figure 2 or 13 in Figure 3, and the focal point shift (ΔZ) to be compensated for is
is expressed by the following equation.

ΔZ=−α(ΔΦ ² _x +ΔΦ ² _y ) (for electrostatic deflector)
...(4) ΔZ=-α _n (I ² _x + I ² _y ) (for magnetic field deflector)
...(5) In the above equations (4) and (5), α and α _n are proportionality constants of the focal point compensation current. The lens current of the focusing electron lens is adjusted so that the focused electron beam forms a circle of least confusion on the sample surface when not being deflected.

Next, second-order astigmatism caused by deflection
The compensation principle for Ne ⁱ² 〓 ²・ωe ^-ix and third-order astigmatism Ce ⁱ³ 〓 ³・ω ² e ^-i2x will be explained.

When the deflector 2 is an electrostatic type shown in FIG. 2, each voltage ψ ₁ , ψ ₂ , ψ ₃ ... ψ ₈ is applied to each of the eight electrodes A to H, ψ ₁ = φ ₁ , ψ ₂ = φ ₂ , ψ ₃ = −φ ₁ , ψ ₄ = −φ ₂
, ψ ₅ = φ ₁ , ψ ₆ = φ ₂ , ψ ₇ = −φ ₁ , ψ ₈ = −φ ₂ ...(6) Two sets of positive potentials (φ ₁ , φ ₂ ) and two sets of positive potentials (φ 1 , φ 2 ) When a negative potential (-φ ₁ , -φ ₂ ) is applied, a second-order astigmatism Δu ₂ is generated as follows: Δu ₂ =N ₂ ωe ^-i(X-2 〓 ²⁾ (7). Here _N2 is
The aberration coefficient is proportional to √ ² ₁ + ² ₂ , and its direction is
It is determined by tan2λ ₂ =φ ₂ /φ ₁ . Further, ω is the beam aperture angle, e is an exponential function, i=√−1 is an imaginary unit expressed as a complex number, X is the phase of ω, and 2λ ₂ is the phase of N ₂ . This second-order astigmatism has a direction of λ ₂ ,
In the direction of λ ₂ by arbitrarily changing φ ₁ and φ ₂
The amount can be N ₂ ω.

Similarly, each voltage ψ ₁ , ψ ₂ , ψ ₃ ... ψ ₈ is applied to each electrode A to H of the deflector 2, Applying the potentials of φ ₁ ′ and φ ₃ ′ so that
The following astigmatism Δu ₃ = N ₃ ω ² e ^-i(2x-3x3) , tan3λ ₃ = φ ₃ ′/φ ₁ ′……(
9) occurs. Here, N ₃ is the aberration coefficient and 3λ ₃ is its phase. The direction λ ₃ and magnitude N ₃ ω ² of this third-order astigmatism can be changed by changing φ ₁ ' and φ ₃ '. (N ₃ is proportional to √ ₁ ′ ² + ₂ ′ ^2. ) In this way, the above-mentioned potentials φ ₁ , φ ₂ , φ ₁ ′, and φ ₃ ′ are applied to each electrode of the deflector, and the following relationship is established. , ψ ₁ =φ ₁ +φ ₁ ′ψ ₄ = −φ ₂ +φ′ ₄ ψ ₇ = −φ ₁
−φ ₃ ′ ψ ₁ = φ ₁ +φ ₁ ′ψ ₄ = −φ ₂ +φ′ ₄ ψ ₇ = −φ ₁
−φ ₃ ′ψ ₂ =φ ₂ +φ ₂ ′ψ ₅ =φ ₁ −φ ₁ ′ψ ₈ =−φ ₂ −
φ ₄ ′ ψ ₃ = φ ₁ + φ ₃ ′ψ ₆ = φ ₂ −φ ₂ ′ ...(10) By applying in advance, second-order and third-order astigmatism occur simultaneously, and the astigmatism is The point aberration can cancel out the astigmatism that the deflected beam shown in equation (1) has before compensation. For this reason, the amount of astigmatism N ₂ ω (Equation 7) caused by the potentials φ ₁ and φ ₂ for second-order astigmatism compensation is the same as that before the compensation shown in Equation (1). It is adjusted by the astigmatism compensation circuit 9 so that it is equal to the astigmatism amount Nω and its directions are opposite to each other, that is, δ ₂ =λ ₂ +π/2. Similarly 3
Regarding the next astigmatism compensation, the compensation condition N ₃ =C,
The astigmatism compensation circuit 10 adjusts so that δ ₃ =λ ₃ +π/3 holds.

Therefore, φ ₁ , φ ₂ , φ ₁ ′, φ ₃ ′ are determined from the above-mentioned second-order and third-order astigmatism compensation conditions, and combined with equation (2) that gives the distortion aberration compensation deflection voltage described above, ( 10) The following voltages ψ ₁ , ψ ₂ , ψ ₃ ...ψ ₈ ψ ₁ = ΔΦ _xc + g (ΔΦ ² _x −ΔΦ ² _y ) −2gΔΦ _x ΔΦ _y
−j(ΔΦ _x cos3/8π+ΔΦ _y sin3/8π) ψ ₂ =ΔΦ _xc +g(ΔΦ ² _x −ΔΦ ² _y )+2gΔΦ _x ΔΦ _y
+j (ΔΦ _x cosπ/8+ΔΦ _y sinπ/8) ψ ₃ =ΔΦ _yc −g (ΔΦ ² _x −ΔΦ ² _y ) +2gΔΦ _x ΔΦ _y
−j (ΔΦ _x sin3/8π+ΔΦ _y cos3/8π) ψ ₄ =ΔΦ _yc −g (ΔΦ ² _x −ΔΦ ² _y ) −2gΔΦ _x ΔΦ _y
−j (ΔΦ _x cos5/8π+ΔΦ _y sin5/8π) ψ ₅ = −ΔΦ _xc +g (ΔΦ ² _x −ΔΦ ² _y ) −2gΔΦ _x ΔΦ
_y + j (ΔΦ _x cos3/8π + ΔΦ _y sin3/8π) ψ ₆ = −ΔΦ _xc + g (ΔΦ ² _x −ΔΦ ² _y ) + 2gΔΦ _x ΔΦ
_y −j (ΔΦ _x cosπ/8+ΔΦ _y sinπ/8) ψ ₇ = −ΔΦ _yc −g (ΔΦ ² _x −ΔΦ ² _y ) + 2gΔΦ _x ΔΦ
_y + j (ΔΦ _x sin3/8π−ΔΦ _y cos3/8π) ψ ₈ = −ΔΦ _yc −g (ΔΦ ² _x −ΔΦ ² _y ) −2gΔΦ _x ΔΦ
By applying _y + j (ΔΦ _x cos5/8π+ΔΦ _y sin5/8π) (11) to each of the eight electrodes A to H of the deflector 2, the deflection aberration can be compensated.

The principle of astigmatism compensation described above is exactly the same when the deflector is a magnetic field type deflector. That is, the second
In the case of the electrostatic deflector 11 shown in the figure, the deflection voltages ±ΔΦ _x and ±ΔΦ _y are replaced by the deflection currents ±I _x and ±I _y ,
In order to compensate for deflection aberration, a magnetic field type deflector 17 is used.
Currents I ₁ , I ₂ , I ₃ ... I ₈ supplied to each magnetic pole A to H of
can be given as follows. That is, I ₁ = I _xc −g _n (I ² _x −ΔI ² _y ) + 2g _n I _x I _y −j _n (I _x cos
3/8π+I _y sin 3/8π) I ₂ =I _xc −g _n (I ² _x −I ² _y )−2g _n I _x I _y +j _n (I _x cosπ
/8+I _y sinπ/8) I ₃ = I _yc +g _n (I ² _x −I ² _y )−2g _n I _x I _y −j _n (I _x sin3
/8π−I _y cos3/8π) I ₄ =I _yc +g _n (I ² _x −I ² _y )+2g _n I _x I _y −j _n (I _x cos5
/8π+I _y sin5/8π) I ₅ = −I _xc −g _n (I ² _x −I ² _y ) + 2g _n I _x I _y +j _n (I _x cos
3/8π + I _y sin 3/8π) I ₆ = −I _xc −g _n (I ² _x −I ² _y )−2g _n I _x I _y −j _n (I _x cos
π/8+I _y sin π/8) I ₇ =−I _yc +g _n (I ² _x −I ² _y )−2g _n I _x I _y +j _n (I _x sin
3/8π−I _y cos3/8π) I ₈ =−I _yc +g _n (I ² _x −I ² _y ) + 2g _n I _x I _y +j _n (I _x cos
5/8π+I _y sin5/8π) By compensating for the distortion aberration, second- and third-order astigmatism, and focal shift ΔZ described above, the deflection aberration Δu
becomes small as Δu=Aω ² +Bω ² e ^2ix −1/4C _s ω ³ e ^ix (12). Here, the first term and the second term of equation (13) are
The amount of comatic aberration in the term is as small as 0.1 μm or less even when the scanning range is a wide square with a side of 2 cm.
In addition, the diameter of the circle of least confusion in the third term of equation (13) can also be determined by shortening the distance between the focusing lens and the sample surface because the device of this invention allows deflection in the X and Y directions with one deflector. As a result of this design, the amount of spherical aberration is reduced to 0.1 μm or less. This makes it possible to reduce the size of the scanning beam spot to submicron or less.

Next, referring to FIG. 2, we will explain how to supply the current of equation (4) above to the focus compensation lens 18 in the electrostatic deflector, and to each electrode A to H of the electrostatic deflector 11. A method of applying the voltage expressed by equation (11) above will be explained.

In FIG. 2, as mentioned above, 6 is a deflection voltage power supply, 7 is a focus compensation circuit, and 8, 9, 10
indicates a deflection aberration compensation circuit.

The focus compensation circuit 7 receives ± from the deflection voltage power supply 6.
Using the deflection voltages ΔΦ _x and ±ΔΦ _y , the equation (4) is calculated and a focus compensation voltage is applied to the focus compensation lens 18. The distortion aberration compensation circuit 8 calculates equation (2) using ±ΔΦ _x and ±ΔΦ _y , generates deflection voltages ±ΔΦ _xc and ± _{ΔΦ yc} that compensate for distortion aberrations, and applies ±ΔΦ 1
-ΔΦ _xc to electrodes A and B of 1, +
ΔΦ _yc is applied to electrodes C and D, and -ΔΦ _yc is applied to electrodes G and H, respectively. 2nd and 3rd order astigmatism compensation circuits 9 and 1
0 uses ±ΔΦ _x and ±ΔΦ _y to perform the calculations shown in Figure 2 9 and 10 to generate an astigmatism compensation voltage, and then superimposes this voltage on _the aforementioned ± _ΔΦ Then, the voltage is applied to each electrode A to H of the deflector 11, respectively.

Next, referring to FIG. 3, we will explain how to supply the current of formula (5) above to the focus compensation lens 18 in the magnetic field deflector, and to each of the magnetic poles A to H of the magnetic field deflector 17. A method of supplying the current expressed by equation (12) above will be explained.

In FIG. 2, as mentioned above, 12 is a deflection current power supply, 13 is a focus compensation circuit, and 14,
15 and 16 indicate deflection aberration compensation circuits.

The focus compensation circuit 13 uses the deflection currents of ±I _x and ±I _y from the deflection current power source 12 to calculate equation (5),
A focus compensation current is supplied to the focus compensation lens 18. The distortion aberration compensation circuit 14 uses ±I _x and ±I _y.
Equation (3) is calculated to generate deflection currents ±I _xc and ±I _yc that compensate for distortion aberrations, and +I _xc is applied to the electrode A of the deflector 17,
B, -I _xc to electrodes E and F, +I _yc to electrodes C and D,
-I _yc is supplied to electrodes G and H, respectively. The secondary and tertiary astigmatism compensation circuits 15 and 16 use ±I _xc and ±I _yc to perform the calculations shown in FIG. 3 15 and 16 to generate astigmatism compensation currents, and By superimposing the current on the above-mentioned ±I _xc and ±I _yc , each electrode A of the deflector 17
~H, respectively.

Each calculation in FIGS. 2 and 3 described above can be performed under the control of a computer, an A/D converter, and the like. In this case, the above method can also be used when deflecting the beam to an arbitrary scanning position.
Since each calculation of equations (4), (5), (11), and (12) can be performed for any deflection voltage or current, it is possible to scan the beam without aberration in the flying spot mode.

It goes without saying that the present invention can be applied in addition to the above-described embodiments to, for example, scanning and deflecting an ion beam focused by an electrostatic lens.

As explained above, according to the present invention, a focus compensation voltage or current proportional to a deflection voltage or current for deflecting a beam is supplied to a focus compensation lens to compensate for a focus shift, and at the same time Distortion aberration compensation according to voltage or current for deflection, 2
By supplying voltage or current for second- and third-order astigmatism compensation to each electrode or magnetic pole of the deflector, it is possible to prevent the beam diameter on the sample surface from increasing due to deflection, resulting in electron beam exposure. It is clear that this method has a significant effect on devices that require the beam irradiation area to be kept small at all times, such as scanning electron microscopes and scanning electron microscopes.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the electron beam deflection device, Figure 2 is a schematic diagram of the electron beam deflection device;
The figure is a block diagram of an embodiment of the invention using an electrostatic deflector, FIG. 3 is a block diagram of an embodiment of the invention using a magnetic field deflector, and FIGS.
FIG. 3 is a diagram showing a pattern of a deflected beam. In the drawings, 1... Magnetic field type electron lens, 2... Deflector, 3...
...sample surface, 4, 5...beam, 4'...optical axis, 6
... Deflection voltage power supply, 7 ... Focus compensation circuit, 8,
9, 10... Aberration compensation circuit, 11... Electrostatic deflector, 12... Deflection current power supply, 13... Focus compensation circuit, 14, 15, 16... Aberration compensation circuit, 17...
...Magnetic field type deflector, 18... Focus compensation lens.

Claims (1)

[Scope of Claims] 1. At least an electrostatic or magnetic field type lens for focusing a charged beam, and at least one lens arranged symmetrically with respect to an optical axis for two-dimensionally deflecting the charged beam on a sample surface. In an automatic aberration compensation deflection device comprising a deflector consisting of eight electrodes or magnetic poles, two of the deflection voltages or currents supplied to the deflector are provided.
a focus compensation circuit that supplies a focus compensation voltage or current proportional to an aberration compensation circuit that superimposes at least eight types of aberration compensation voltages or currents corresponding to the deflection voltages or currents on the deflection voltages or currents and supplies them to each electrode or magnetic pole of the deflector. An aberration automatic compensation deflection device featuring: 2. The deflection voltages are ΔΦ _x and ΔΦ _y , a is a proportionality constant for generating the focus compensation voltage or current, and b, c, and d are the deflection voltages for compensating for distortion and aberration caused by beam deflection. The coefficients of the voltage applied to each electrode of the device, g and j, are respectively 2
When the proportionality constant of the voltage applied to each electrode of the deflector is used to compensate for next- and third-order astigmatism, the amount of defocus due to the focus compensation voltage or current ΔZ
and the voltages ψ ₁ , ψ ₂ , ψ ₃ ...ψ ₈ generated by the aberration compensation circuit and applied to the eight electrodes of the deflector.
However, the following formula, ΔZ=−a(ΔΦ ² _x +ΔΦ ² _y ), ψ ₁ =ΔΦ _x +bΔΦ _x √ ² _x + ² _y +c(ΔΦ ² _x +Δ
Φ ² _y ) ΔΦ _x +dΔΦ _x +g(ΔΦ ² _x −ΔΦ ² _y )−2gΔΦ _x ΔΦ _y −j(ΔΦ _x c
os3/8π+ΔΦ _y sin3/8π), ψ ₂ =ΔΦ _x +bΔΦ _x √ ² _x + ² _y +c (ΔΦ ² _x +Δ
Φ ² _y ) ΔΦ _x +dΔΦ _x +g(ΔΦ ² _x −ΔΦ ² _y )+2gΔΦ _x ΔΦ _y +j(ΔΦ _x c
osπ/8+ΔΦ _y sinπ/8), ψ ₃ =ΔΦ _y +bΔΦ _y √ ² _x + ² _y +c(ΔΦ ² _x +Δ
Φ ² _y ) ΔΦ _y +dΔΦ _y −g(ΔΦ ² _x −ΔΦ ² _y )+2gΔΦ _x ΔΦ _y −j(ΔΦ _x s
in3/8π−ΔΦ _y cos3/8π), ψ ₄ =ΔΦ _y +bΔΦ _y √ ² _x + ² _y +c (ΔΦ ² _x + Δ
Φ ² _y ) ΔΦ _y +dΔΦ _y −g(ΔΦ ² _x −ΔΦ ² _y )−2gΔΦ _x ΔΦ _y −j(ΔΦ _x c
os5/8π+ΔΦ _y sin5/8π), ψ ₅ = −ΔΦ _x −bΔΦ _x √ ² _x + ² _y −c (ΔΦ ² _x +
ΔΦ ² _y ) ΔΦ _x −dΔΦ _x +g(ΔΦ ² _x −ΔΦ ² _y )−2gΔΦ _x ΔΦ _y +j(ΔΦ _x c
os3/8π+ΔΦ _y sin3/8π), ψ ₆ = −ΔΦ _x −bΔΦ _x √ ² _x + ² _y −c (ΔΦ ² _x +
ΔΦ ² _y ) ΔΦ _x −dΔΦ _x +g(ΔΦ ² _x −ΔΦ ² _y )+2gΔΦ _x ΔΦ _y −j(ΔΦ _x c
osπ/8+ΔΦ _y sinπ/8), ψ ₇ =−ΔΦ _y −bΔΦ _y √ ² _x + ² _y −c(ΔΦ ² _x +
ΔΦ ² _y ) ΔΦ _y −dΔΦ _y −g(ΔΦ ² _x −ΔΦ ² _y )＋2gΔΦ _x ΔΦ _y +j(ΔΦ _x s
in3/8π−ΔΦ _y cos3/8π), ψ ₈ =−ΔΦ _y −bΔΦ _y √ ² _x + ² _y −c(ΔΦ ² _x +
ΔΦ ² _y ) ΔΦ _y −dΔΦ _y −g(ΔΦ ² _x −ΔΦ ² _y )−2gΔΦ _x ΔΦ _y +j(ΔΦ _x c
The aberration automatic compensation deflection device according to claim 1, wherein the aberration automatic compensation deflection device satisfies the following: os5/8π+ΔΦ _y sin5/8π). 3 The deflection currents are I _x and I _y , a _n is a proportionality constant for generating the focus compensation voltage or current, and b _n , c _n , and d _n are the compensation for distortion aberration caused by beam deflection. In order to compensate for the second-order and third-order astigmatism caused by deflection, g _n and j _n are respectively supplied to each magnetic pole of the deflector in order to compensate for the second-order and third-order astigmatism caused by deflection. When taken as a proportional constant of the current, the amount of focus shift ΔZ due to the focus compensation voltage or current, and the currents I ₁ , I ₂ , generated by the aberration compensation circuit and supplied to the eight magnetic poles of the deflector.
I ₃ ... I ₈ is the following formula, ΔZ = -a _n (I ² _x + I ² _y ), I ₁ = I _x + b _n I _y √ ² _x + ² _y + c _n (I ² _x + I ² _y ) I _x +d _n I _x −g _n (I ² _x −I ² _y ) + 2g _n I _x I _y −j _n (I _x cos3/8π+l _y
sin3/8π), I ₂ = I _x + b _n I _y √ ² _x + ² _y + c _n (I ² _x + I ² _y ) I _x + d _n I _x −g _n (I ² _x −I ² _y ) − 2g _n I _x I _y +j _n (I _x cosπ/8+l _y si
nπ/8), I ₃ = I _y −b _n I _x √ ² _x + ² _y + c _n (I ² _x + I ² _y ) I _y + d _n I _y + g _n (I ² _x − I ² _y ) − 2g _n I _x I _y −j _n (I _x sin3/8π−I _y
cos3/8π), I ₄ = I _y −b _n I _x √ ² _x + ² _y + c _n (I ² _x + I ² _y ) I _y + d _n I _y + g _n (I ² _x − I ² _y ) + g _n I _x I _y −j _n (I _x cos5/8π+I _y s
in5/8π), I ₅ = −I _x −b _n I _y √ ² _x + ² _y −c _n (I ² _x + I ² _y ) I _x −d _n I _x −g _n (I ² _x −I ² _y )＋g _n I _x I _y +j _n (I _x cos3/8π＋I _y s
in3/8π), I ₆ = −I _x −b _n I _y √ ² _x + ² _y −c _n (I ² _x + I ² _y ) I _x −d _n I _x −g _n (I ² _x −I ² _y ) −g _n I _x I _y −j _n (I _x cosπ/8+I _y sin
π/8), I ₇ = −I _y + b _n I _x √ ² _x + ² _y −c _n (I ² _x + I ² _y ) I _y −d _n I _y + g _n (I ² _x −I ² _y ) −2g _n I _x I _y +j _n (I _x sin3/8π−I _y
cos3/8π), I ₈ = −I _y + b _n I _x √ ² _x + ² _y −c _n (I ² _x + I ² _y ) I _y −d _n I _y + g _n (I ² _x −I ² _y ) +2g _n I _x I _y +j _n (I _x cos5/8π+I _y
The automatic aberration compensation deflection device according to claim 1, characterized in that the deflection device satisfies the following: sin5/8π).