JP2024070593A - Electron beam irradiation device - Google Patents

Abstract

To provide a device capable of suppressing charging of an insulator in an electron beam column.SOLUTION: An electron beam irradiation device includes an electrode that is disposed within an electron beam column, is formed axially symmetrically with respect to the central axis of the electron beam orbit, has an opening in the center through which the electron beam passes, and is formed such that its thickness tapers from the outer periphery toward the opening, a conductive cap that is disposed within the electron beam column at a distance from the electrode, is formed axially symmetrically with respect to the central axis of the electron beam orbit, has an opening in the center through which the electron beam passes, and has a surface that faces the electrode at an angle that is not parallel to the surface of the electrode, a conductive holder that connects the cap on the outer periphery side within the electron beam column, and an insulator that is disposed within the electron beam column between the electrode and the holder to insulate the electrode and the holder, and the insulator is formed so as to narrow the path of reflected electrons emitted when the sample is irradiated with the electron beam toward the insulator.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electron beam irradiation device, and for example, to a method for suppressing charging of an insulator in an electron beam column.

Lithography technology, which is responsible for the advancement of miniaturization of semiconductor devices, is an extremely important process in the semiconductor manufacturing process that is the only one that generates patterns. In recent years, with the increasing integration density of LSIs, the circuit line width required for semiconductor devices has become finer year by year. Here, electron beam (electron beam) drawing technology inherently has excellent resolution, and circuit patterns are drawn using electron beams on wafers or masks that form patterns on wafers.

In an electron beam lithography device, an electrostatic lens and/or an electrostatic deflector that controls the trajectory of the electron beam are arranged in an electron optical lens tube (electron beam column). A control potential is applied to the electrodes that constitute the electrostatic lens and/or the electrostatic deflector. An insulating member is arranged to insulate these electrodes from peripheral components that have the same potential as the ground potential. In order to prevent the insulating member from becoming charged, the insulating member is hidden from the trajectory space of the electron beam, for example, by using a shielding member. However, there are cases in which reflected electrons emitted when the electron beam collides with, for example, an aperture substrate or a sample surface may reach the insulating member through, for example, a gap between the shielding member and the electrode. As a result, there is a problem that the insulating member becomes charged by the reflected electrons, and when the amount of charge exceeds a limit, it discharges, affecting the electron beam trajectory. As a result, the lithography accuracy deteriorates.

Here, a technique has been disclosed in which a V-shaped notch is formed in an anti-reflection plate placed above the sample surface to attenuate electrons that enter the notch (see, for example, Patent Document 1).

JP 2014-143393 A

One aspect of the present invention provides an apparatus capable of suppressing charging of an insulator in an electron beam column.

An electron beam irradiation apparatus according to one aspect of the present invention comprises:
an electron beam column for irradiating a sample with an electron beam;
an electrode disposed in the electron beam column, formed axially symmetrically with respect to a central axis of the orbit of the electron beam, with an opening formed in the center through which the electron beam passes, and formed so that the thickness of the electrode tapers from the outer periphery toward the opening;
a conductive cap disposed in the electron beam column and spaced apart from the electrode, formed axially symmetrically with respect to a central axis of the electron beam trajectory, having an opening at its center through which the electron beam passes, and having a surface opposed to a surface of the electrode at an angle not parallel to the surface of the electrode;
a conductive holder for connecting the cap to the outer periphery of the electron beam column;
an insulator disposed between the electrode and the holder in the electron beam column to insulate the electrode from the holder;
Equipped with
The electrode and the cap are characterized in that they are formed so as to narrow the path of reflected electrons emitted when the sample is irradiated with an electron beam, which penetrates between the surface of the electrode and the surface of the cap, toward the insulator.

In addition, the conductive cap is
a conductive lower cap disposed within the electron beam column below the electrode and spaced apart, the conductive lower cap having a central opening through which the electron beam passes and an upper surface opposed at a non-parallel angle to the lower surface of the electrode;
a conductive upper cap disposed in the electron beam column above the electrode in spaced relation thereto, the upper cap having a central opening through which the electron beam passes and a lower surface opposed at a non-parallel angle to the upper surface of the electrode;
It is preferable that the optical fiber 100 be composed of the following components:

Alternatively, as the above-mentioned electrodes, a plurality of electrodes having two or more poles each having a thickness tapering toward the center are used,
the cap is disposed in the electron beam column at a distance from the plurality of electrodes, is formed axially symmetrical with respect to a central axis of the electron beam trajectory, and has at least one surface opposed to the surfaces of the plurality of electrodes at an angle that is not parallel to the surfaces of the electrodes;
As the insulator, a plurality of insulators are used in the electron beam column, the insulators being connected to the holder on the outer periphery side of the holder and connected to corresponding ones of the plurality of electrodes, and insulating the corresponding ones of the plurality of electrodes from the holder,
The multiple electrodes and the cap are preferably configured to narrow the path of reflected electrons emitted by irradiating the sample with an electron beam, which penetrate between the surfaces of the multiple electrodes and at least one surface of the cap, toward the insulator.

In addition, the cap is
a conductive upper cap disposed in the electron beam column in spaced relation above the plurality of electrodes and having at least one lower surface opposed at a non-parallel angle to the upper surfaces of the plurality of electrodes;
a conductive lower cap disposed in a spaced relationship below the plurality of electrodes within the electron beam column and having at least one upper surface opposed at a non-parallel angle to the lower surfaces of the plurality of electrodes;
It is preferable that the optical fiber 100 be composed of the following components:

Another aspect of the electron beam irradiation apparatus of the present invention is
an electron beam column for irradiating a sample with an electron beam;
a conductive aperture substrate disposed within the electron beam column, formed axially symmetrically with respect to a central axis of the electron beam trajectory, having an aperture formed at the center thereof through which the electron beam passes, and blocking electrons of the electron beam that deviate from the aperture;
a conductive aperture holder connected to an outer periphery of an upper surface of the aperture substrate, formed symmetrically with respect to a central axis of the electron beam trajectory, and formed so that its thickness tapers downward;
a conductive ring formed in an electron beam column symmetrically with respect to a central axis of an electron beam trajectory, disposed on an inner peripheral side of the aperture holder at a distance, and having an outer peripheral surface facing the inner peripheral surface of the aperture holder at an angle that is not parallel to the inner peripheral surface of the aperture holder;
a ring holder that supports the ring above the ring;
an insulator disposed between the ring holder and the aperture holder in the electron beam column to provide insulation between the ring holder and the aperture holder;
Equipped with
The aperture holder and the ring are characterized in that they are formed so as to narrow the path of reflected electrons emitted when an electron beam is irradiated onto the aperture substrate, which penetrates between the inner surface of the aperture holder and the outer surface of the ring, toward the insulator.

In addition, it is preferable that the path of the reflected electrons is formed from the opposing first and second wall surfaces toward the insulator and is inclined at a certain angle so as to narrow the path of the reflected electrons.

In addition, the path of the reflected electrons is formed by the first and second wall surfaces facing each other, and the inclination angle of the wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is smaller than the incidence angle θ of the reflected electrons,
It is preferable to arrange the first and second wall surfaces so that the sum of the tangent of the inclination angle α of the first wall surface and the tangent of the inclination angle β of the second wall surface is greater than the difference obtained by subtracting the cosine of the incidence angle θ of the reflected electrons from 1, multiplied by the distance B between the first and second wall surfaces where the reflected electrons begin to penetrate, and divided by the opposing length H of the first and second wall surfaces.

Alternatively, the path of the reflected electrons is formed by opposing first and second wall surfaces, and it is preferable to arrange the first and second wall surfaces so that the inclination angle of the wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is equal to or greater than the incidence angle θ of the reflected electrons.

Alternatively, the path of the reflected electrons is formed by first and second wall surfaces facing each other, and the inclination angle of the wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is smaller than the incidence angle θ of the reflected electrons,
It is preferable to arrange the first and second wall surfaces so that the sum of the tangent of the inclination angle α of the first wall surface and the tangent of the inclination angle β of the second wall surface is less than or equal to the difference obtained by subtracting the cosine of the incidence angle θ of the reflected electrons from 1, multiplying it by the distance B between the first and second wall surfaces where the reflected electrons begin to penetrate, and dividing the result by the opposing length H of the first and second wall surfaces.

According to one aspect of the present invention, charging of the insulator in the electron beam column can be suppressed or reduced. This allows for highly accurate beam irradiation. As a result, highly accurate drawing can be achieved.

FIG. 1 is a conceptual diagram showing a configuration of a drawing device according to a first embodiment. 2 is a diagram showing an example of a configuration of an electrostatic lens in the first embodiment; 2 is a top view showing an example of a configuration of an electrostatic lens in the first embodiment. FIG. 2 is a cross-sectional view showing a portion of an example of the configuration of an electrostatic lens in the first embodiment. FIG. 5A to 5C are diagrams for explaining an example of an inclination angle of a wall surface and a state in which reflected electrons enter in the first embodiment. 10A to 10C are diagrams for explaining another example of the inclination angle of the wall surface and the penetration of reflected electrons in the first embodiment. FIG. 4 is a diagram showing an example of a penetration model of reflected electrons in the first embodiment. 10A to 10C are diagrams for explaining another example of the inclination angle of the wall surface and the penetration of reflected electrons in the first embodiment. 10A to 10C are diagrams for explaining an example of a cross-sectional configuration of a deflector in a modification of the first embodiment and a state in which reflected electrons enter the deflector; 13 is a top cross-sectional view showing an example of a configuration of a CC cross section of a deflector in a modified example of the first embodiment. FIG. FIG. 13 is a top view showing another example of the lower cap in the modified example of the first embodiment. 4A to 4C are diagrams for explaining an example of a cross-sectional configuration of a limiting aperture mechanism in the first embodiment and a state in which reflected electrons enter the limiting aperture mechanism; 4 is a top view of an example of the configuration of a limiting aperture mechanism in the first embodiment. FIG.

In the following embodiments, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and may be a beam using charged particles such as an ion beam. In addition, an electron beam drawing device will be described as an example of an electron beam irradiation device, but the present invention is not limited to this. For example, any device that irradiates an electron beam, such as an electron beam inspection device, may be used.

Embodiment 1.
Fig. 1 is a conceptual diagram showing a configuration of a drawing apparatus in the first embodiment. In Fig. 1, the drawing apparatus 100 includes a drawing mechanism 150 and a control circuit 160. The drawing apparatus 100 is an example of an electron beam irradiation apparatus. The drawing mechanism 150 includes an electron beam column 102 (electron lens barrel) and a drawing chamber 103. In the electron beam column 102, an electron gun 201, an illumination lens 202, a limiting aperture mechanism 212, a deflector 204, an electrostatic lens 214, and an objective lens 206 are arranged.

A stage 105 is placed in the drawing chamber 103. A sample 101, such as a mask, which will be the substrate to be drawn on during drawing (exposure) is placed on the stage 105. The sample 101 includes an exposure mask used when manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured. The sample 101 also includes mask blanks on which resist is applied and on which nothing is yet drawn.

The electron beam column 102 is supported by the drawing chamber 103, for example, so that a portion of its lower portion is located within the drawing chamber 103.

The drawing chamber 103 and the electron beam column 102 are evacuated by a vacuum pump (not shown), and are used in a vacuum state during drawing processing.

The control system circuit 160 has a control computer 110, a memory 112, a lens control circuit 124, a deflection control circuit 130, and a storage device 140 such as a magnetic disk device. The control computer 110, the memory 112, the lens control circuit 124, the deflection control circuit 130, and the storage device 140 are connected to each other via a bus 120. The deflector 204 is composed of four or more electrodes, and is controlled by the deflection control circuit 130 via a DAC (digital-analog converter) amplifier (not shown) for each electrode. The illumination lens 202, the limiting aperture mechanism 212, the electrostatic lens 214, and the objective lens 206 are controlled by the lens control circuit 124. The position of the stage 105 is controlled by a stage control mechanism (not shown). The stage 105 is also controlled by driving motors for each axis (not shown). The position of the stage 105 is measured by a laser interferometer (not shown) based on the principle of laser interferometry.

Information input and output to the control computer 110 and information being calculated are stored in memory 112 each time.

The drawing operation of the drawing device 100 is controlled by a control computer 110 that controls the entire drawing device 100.

In addition, chip data is input from outside the drawing device 100 and stored in the memory device 140. The chip data defines information on multiple graphic patterns that make up the chip to be drawn. Specifically, for each graphic pattern, for example, a graphic code, coordinates, size, etc. are defined.

Here, FIG. 1 shows the configuration necessary for explaining the first embodiment. The drawing device 100 may also be provided with other configurations that are normally required.

Next, a specific example of the operation of the drawing mechanism 150 will be described. The electron beam column 102 irradiates the sample 101 with an electron beam 200. Specifically, for example, it operates as follows. The electron beam 200 emitted from the electron gun 201 (emission source) is converted into a beam of the desired magnification by the illumination lens 202 and the objective lens 206, and irradiates the sample 101. At that time, the objective lens 206 forms an image of the electron beam 200 on the surface of the sample 101.

The limiting aperture mechanism 212 also has an opening in the center through which the electron beam 200 passes. It blocks scattered electrons and the like that miss the opening. The electrostatic lens 214, which has better responsiveness than the objective lens 206, which is a magnetic lens, dynamically corrects the focal position of the electron beam 200 in response to the unevenness on the substrate.

In addition, a desired potential is applied to the deflector 204 from the deflection control circuit 130 controlled by the control computer 110 via a DAC amplifier (not shown). The deflector 204 deflects the electron beam to a desired position on the surface of the sample 101 according to the applied potential.

For example, the control computer 110 reads the chip data from the storage device 140 and generates shot data for each shot through a data conversion process. The shot data defines the irradiation position of the electron beam for that shot. Each position on the sample surface has a fixed distance from the stage position being measured. Therefore, if the stage position is known, the relative position on the sample surface can be known. The blanking operation between shots may be controlled by a blanking aperture and blanking deflector (not shown).

The deflection control circuit 130 therefore controls the deflector 204 to correct the irradiation position of the electron beam 200 on the sample 101 according to the position of the stage 105. Specifically, when the stage 105 reaches a position where the electron beam 200 can irradiate the irradiation position defined in the shot data, the deflector 204 deflects the electron beam 200 toward the irradiation position. This allows the electron beam 200 to irradiate the desired position.

Figure 2 is a diagram showing an example of the configuration of an electrostatic lens in embodiment 1. In the example of Figure 2, an electrostatic lens 214 is described that is configured, for example, with three stages of electrode substrates. In Figure 2, the electrostatic lens 214 has a conductive upper cap 16 (upper stage electrode substrate member), a conductive electrode 10 (middle stage electrode member), a conductive lower cap 14 (lower stage electrode substrate member), an insulator 12, and a conductive holder 18 (connecting member).

FIG. 3 is a top view showing an example of the configuration of the electrostatic lens in the first embodiment.
Fig. 4 is a cross-sectional view showing a part of an example of the configuration of the electrostatic lens in embodiment 1. The upper cap 16, the electrode 10, the lower cap 14, the insulator 12, and the holder 18 are formed symmetrically with respect to the central axis of the orbit of the electron beam 200. Fig. 4 shows the right side of the cross section. The left side of the cross section is not shown.

As shown in FIG. 3, the upper cap 16, the electrode 10, and the lower cap 14 are formed, for example, in a disk shape. Also, as shown in FIG. 3 and FIG. 4, the upper cap 16, the electrode 10, and the lower cap 14 each have a circular opening 7, 5, 6 formed in the center for the electron beam 200 to pass through. The holder 18 is formed, for example, in a ring shape. Also, the insulator 12 is formed, for example, in a ring shape. The upper cap 16 functions as an upper electrode substrate of the electrostatic lens 214. The electrode 10 functions as a middle electrode substrate of the electrostatic lens 214. The lower cap 14 functions as a lower electrode substrate of the electrostatic lens 214.

2 and 4, the upper cap 16 is disposed above the electrode 10 in the electron beam column 102 at a distance. The lower cap 14 is disposed below the electrode 10 in the electron beam column 102 at a distance. The holder 18 is connected to the upper cap 16 and the lower cap 14 on the outer periphery side in the electron beam column 102. In the example of FIGS. 2 to 4, the upper cap 16 is disposed so as to cover the cylindrical holder 18 from above. The lower cap 14 is disposed so as to cover the cylindrical holder 18 from below. In other words, the upper cap 16 and the lower cap 14 are disposed so as to sandwich the electrode 10 from above and below with a gap therebetween, and the outer periphery side is connected to the conductive holder 18. As a result, the upper cap 16 and the lower cap 14 are electrically connected via the holder 18. The lower cap 14, upper cap 16, and holder 18 do not need to be separate parts, but may be integrally formed by machining from the same material.

The electrode 10 is connected to the holder 18 via the insulator 12 on the outer periphery. The insulator 12 is disposed between the electrode 10 and the holder 18 in the electron beam column 102, and insulates the electrode 10 from the holder 18. Thus, the electrode 10 is insulated from the upper cap 16 and the lower cap 14 by the insulator 12. In other words, the wall surface on the lower cap 14 side that is the lower surface of the electrode 10 (an example of a first wall surface) and the wall surface on the electrode 10 side that is the upper surface of the lower cap 14 (an example of a second wall surface) are disposed in a non-contact manner. Furthermore, the walls are electrically insulated from each other by the insulator 12.

Similarly, the wall surface on the electrode 10 side (another example of the first wall surface) which forms the lower surface of the upper cap 16 and the wall surface on the upper cap 16 side (another example of the second wall surface) which forms the upper surface of the electrode 10 are arranged in a non-contact manner. In addition, these wall surfaces are electrically insulated from each other by the insulator 12.

The upper cap 16 and the lower cap 14 are connected to a ground potential (GND) via the holder 18. In other words, the upper cap 16 and the lower cap 14 are grounded. The lens control circuit 124 then applies a desired control potential to the electrode 10. This allows the focal position of the electron beam 200 to be adjusted.

Here, the reflected electrons 300 are emitted by irradiating the sample 101 (an example of an object) with the electron beam 200. The emitted reflected electrons 300 enter the space between the upper cap 16 and the electrode 10 at a predetermined angle of incidence. At that time, if the opposing surfaces of the upper cap 16 and the electrode 10 are arranged parallel to each other, the reflected electrons 300 move forward while repeatedly colliding with the wall surface through the space between the electrode 10 and the lower cap 14 as a passage. Then, the reflected electrons 300 reach the insulator 12 and charge the insulator 12. Then, when the charge amount of the insulator 12 exceeds a certain amount, it discharges, disturbing the electric field in the space A on the trajectory of the electron beam 200. This affects the electron beam 200, causing a deviation in the trajectory of the electron beam 200. As a result, the drawing accuracy is deteriorated.

Similarly, the emitted reflected electrons 300 enter the space between the electrode 10 and the lower cap 14 at a certain angle of incidence. In this case, if the opposing surfaces of the electrode 10 and the lower cap 14 are arranged parallel to each other, the reflected electrons 300 use the space between the electrode 10 and the lower cap 14 as a passage and move forward while repeatedly colliding with the wall surface. The reflected electrons 300 then reach the insulator 12 and charge the insulator 12. When the charge on the insulator 12 exceeds a certain amount, it discharges, disturbing the electric field in space A on the trajectory of the electron beam 200. This affects the electron beam 200, causing a deviation in the trajectory of the electron beam 200. As a result, the drawing accuracy deteriorates.

Therefore, in the first embodiment, the reflected electrons 300 that have entered the space between the upper cap 16 and the electrode 10 are prevented from reaching the insulator 12. Or, even if they do reach the insulator 12, the energy of the reflected electrons 300 is attenuated before they reach the insulator 12. The same applies to the reflected electrons 300 that have entered the space between the electrode 10 and the lower cap 14. This will be explained in detail below.

In FIG. 4, the electrode 10 is formed so that its thickness tapers from the outer periphery toward the opening 5. The lower cap 14 has an upper surface that faces the lower surface of the electrode 10 at a non-parallel angle. Specifically, the wall surface 11 (an example of a first wall surface) on the lower cap 14 side that is the lower surface of the electrode 10 and the wall surface 13 (an example of a second wall surface) on the electrode 10 side that is the upper surface of the lower cap 14 are arranged in the electron beam column 102, and the surfaces face each other at a non-parallel angle without contacting each other. The surface with the wider distance between the facing surfaces is exposed to the space A on the trajectory of the electron beam 200. The wall surface 11 is formed in a tapered shape with an inclination angle α with respect to the horizontal direction. The wall surface 13 is formed in a tapered shape with an inclination angle β with respect to the horizontal direction. In other words, the wall surfaces 11 and 13 are formed so that the space between the wall surfaces 11 and 13 tapers from the space A on the trajectory of the electron beam 200 toward the back of the space between the wall surfaces 11 and 13.

The insulator 12 is disposed within the electron beam column 102 and is disposed on the side where the distance between the opposing wall surfaces 11, 13 is narrowed. The insulator 12 electrically insulates the wall surfaces 11, 13 on the side where the distance between the opposing wall surfaces 11, 13 is narrowed. The insulator 12 is also exposed to the space that continues from within the electron beam column 102 through the space between the wall surfaces 11, 13.

The upper cap 16 also has a lower surface that faces the upper surface of the electrode 10 at an angle that is not parallel to the upper surface of the electrode 10. Specifically, the wall surface 17 (another example of a first wall surface) on the electrode 10 side that is the lower surface of the upper cap 16 and the wall surface 15 (another example of a second wall surface) on the upper cap 16 side that is the upper surface of the electrode 10 are arranged in the electron beam column 102, and the surfaces face each other at an angle that is not parallel to each other without contacting each other, and the surface with the wider distance between the facing surfaces is exposed to the space A on the trajectory of the electron beam 200. The wall surface 17 is formed in a tapered shape with an inclination angle α, for example, with respect to the horizontal direction. The wall surface 15 is formed in a tapered shape with an inclination angle β, for example, with respect to the horizontal direction. In other words, the wall surfaces 15 and 17 are formed so that the space between the wall surfaces 15 and 17 tapers from the space A on the trajectory of the electron beam 200 toward the back of the space between the wall surfaces 15 and 17.

The insulator 12 is disposed within the electron beam column 102 and is disposed on the side where the distance between the opposing wall surfaces 15, 17 is narrowed. The insulator 12 electrically insulates the opposing wall surfaces 15, 17 on the side where the distance between the opposing wall surfaces 15, 17 is narrowed. The insulator 12 is also exposed to the space that continues from within the electron beam column 102 through the space between the wall surfaces 15, 17.

In the example of FIG. 4, for example, a case where reflected electrons 300 penetrate into the space between the electrode 10 and the lower cap 14 will be described. The reflected electrons 300 are emitted by irradiating the sample 101 (an example of an object) with the electron beam 200. The emitted reflected electrons 300 penetrate between the opposing wall surfaces 11 and 13 at an incidence angle θ from the side where the distance between the opposing wall surfaces 11 and 13 is wider. In the first embodiment, the electrode 10 and the lower cap 14 are formed so as to narrow the path of the reflected electrons 300 penetrating between the lower surface of the electrode 10 and the upper surface of the lower cap 14 toward the insulator 12. Specifically, as shown in FIG. 4, the wall surfaces 11 and 13 are arranged so as to narrow the path of the reflected electrons 300 between the wall surfaces 11 and 13 toward the insulator 12. The penetrating reflected electrons 300 proceed through the space between the wall surfaces 11 and 13 while colliding with the wall surfaces 11 and 13. Each time the reflected electrons 300 collide with the wall surface 11 (or wall surface 13), new reflected electrons are emitted radially from the wall surface 11 (or wall surface 13). The example in FIG. 4 shows the trajectory of the reflected electrons 300, among the reflected electrons emitted radially from the collision point, emitted in the same direction as the specular reflection, where the angle of incidence and the angle of reflection are the same with respect to the wall surface 11 (or wall surface 13). The reflected electrons 300 emitted in this direction have the highest energy. The reflected electrons emitted in other directions have low energy, and as the energy decreases further with repeated collisions, the effect on charging becomes negligible. Therefore, a description thereof will be omitted.

For example, the same applies to the case where reflected electrons 300 enter the space between the upper cap 16 and the electrode 10. In the first embodiment, the electrode 10 and the upper cap 16 are formed so as to narrow the path of the reflected electrons 300 that enter between the upper surface of the electrode 10 and the lower surface of the upper cap 16 toward the insulator 12.

Here, the configurations of Cases 1 and 2 below are suitable for preventing the reflected electrons 300 that have entered the space between the wall surfaces 11 and 13 from reaching the insulator 12. Furthermore, even if the reflected electrons 300 do reach the insulator 12, the configuration of Case 3 below is suitable for attenuating their energy. Each case will be described in detail below.

(Case 1)
5 is a diagram for explaining an example of the inclination angle of the wall surface and the state of the reflected electrons entering in the first embodiment. FIG. 5 shows a part of the cross section of the electrode 10, the lower cap 14, the insulator 12, and the holder 18. The cross section of the upper cap 16 is omitted. The example of FIG. 5 shows a case where the inclination angle α of the wall surface 11 with which the reflected electrons 300 first collide is equal to or larger than the incidence angle θ at which the reflected electrons 300 enter. In this case, the reflected electrons 300 are repelled back to the original space at the time when the reflected electrons 300 first collide with the wall surface 11. Therefore, in case 1, the wall surfaces 11 and 13 are arranged so that the inclination angle α of the wall surface 11 with which the reflected electrons 300 first collide after entering between the wall surfaces 11 and 13 is larger than the incidence angle θ of the reflected electrons 300. This makes it possible to prevent the reflected electrons 300 from reaching the insulator 12.

(Case 2)
Fig. 6 is a diagram for explaining another example of the inclination angle of the wall surface in the first embodiment and the state of the penetration of the reflected electrons. Fig. 6 shows a part of the cross section of each of the electrode 10, the lower cap 14, the insulator 12, and the holder 18. The cross section of the upper cap 16 is omitted. In the example of Fig. 6, the inclination angle α of the wall surface 11, which the reflected electron 300 first collides with after penetrating between the wall surfaces 11 and 13, is smaller than the incidence angle θ of the reflected electron 300. Fig. 6 shows the distance B between the wall surfaces 11 and 13 at which the reflected electron 300 starts penetrating, and the opposing length H of the wall surfaces 11 and 13.

7 is a diagram showing an example of a penetration model of reflected electrons in the embodiment 1. In FIG. 7, each parameter is defined as follows.
The distance between the wall surfaces 11 and 13 where the reflected electrons 300 start to penetrate (opening width): B
Length (height) of opposing walls 11 and 13: H
The inclination angle of the wall surface 11 that first collides: α
The inclination angle of the wall surface 13 that will collide next is β
When the space between the trapezoidal wall surfaces 11 and 13 having wall surface inclination angles α and β is repeatedly folded back on both the left and right wall surfaces, it is developed as shown in FIG. 7 with an intersection O of the extension lines of both the left and right wall surfaces as the center.
A reflected electron 300 enters the space between the wall surfaces 11 and 13 at an angle θ, and the trajectory of the reflected electron that repeats specular reflection is represented by a single straight line in a development, and the total number of reflections is 2θ/(α+β).
Here, the distance from point O to the space between the walls 11 and 13 is r
The length of the perpendicular line from point O to the straight line of the development trajectory of the reflected electron 300 is R.
Then, the distance r can be defined by the following equation (1).
(1) r = B / (tan α + tan β) - H

Moreover, the length R can be defined by the following formula (2).
(2) R = B cos θ / (tan α + tan β)

In order for the orbit of the reflected electron 300 not to exceed the height H of the space between the wall surfaces 11 and 13, the following formula (3) should be satisfied.
(3) r < R

Therefore, it is only necessary to satisfy the formula (4) obtained by transforming the formula (3) using the formulas (1) and (2).
(4) (tan α + tan β) > B (1 - cos θ) / H

When (α+β) takes the minimum value within the range that satisfies equation (4), the total number of reflections 2θ/(α+β) is maximized.

Therefore, in case 2, the walls 11 and 13 are arranged so that the sum of the tangent (tan α) of the inclination angle α of the wall surface 11 and the tangent (tan β) of the inclination angle β of the wall surface 13 is greater than the difference obtained by subtracting the cosine (cos θ) of the incidence angle θ of the reflected electron 300 from 1, multiplying the difference by the distance B between the walls 11 and 13 at which the reflected electron 300 starts to penetrate, and dividing the result by the opposing length H of the walls 11 and 13. As a result, the reflected electron 300 is returned to the original space after a total of 2θ/(α+β) reflections. This makes it possible to prevent the reflected electron 300 from reaching the insulator 12.

(Case 3)
Fig. 8 is a diagram for explaining another example of the inclination angle of the wall surface in the first embodiment and the state of the penetration of the reflected electrons. Fig. 8 shows a part of the cross section of each of the electrode 10, the lower cap 14, the insulator 12, and the holder 18. The cross section of the upper cap 16 is not shown. In the example of Fig. 8, the inclination angle α of the wall surface 11, which the reflected electron 300 first collides with after penetrating between the wall surfaces 11 and 13, is smaller than the incidence angle θ of the reflected electron 300. Fig. 8 shows the distance B between the wall surfaces 11 and 13 at which the reflected electron 300 starts penetrating, and the opposing length H of the wall surfaces 11 and 13.

However, in FIG. 8, the relationship satisfies the following formula (5).
(5) (tan α + tan β)≦B(1−cos θ)/H

In this relationship, r>R, and the trajectory of the reflected electron 300 exceeds the height H of the space between the wall surfaces 11 and 13. However, due to the wall surfaces 11 and 13 having the inclination angles α and β, the number of reflections (number of collisions) of the reflected electron 300 becomes greater than in the space of parallel plates. The reflected electron 300 attenuates its energy with each reflection (collision). If the electron absorption rate of the wall surfaces 11 and 13 is a and the total number of reflections is n, the reflected electron is attenuated by (1-a) ⁿ times. Therefore, by increasing the number of reflections (number of collisions), the energy of the reflected electron 300 reaching the insulator 12 can be reduced.

Therefore, in case 3, to satisfy formula (5), the walls 11 and 13 are arranged so that the sum of the tangent of the inclination angle α of the wall 11 and the tangent of the inclination angle β of the wall 13 is equal to or less than the difference obtained by subtracting the cosine of the incidence angle θ of the reflected electrons 300 from 1, multiplying this difference by the distance B between the walls 11 and 13 at which the reflected electrons 300 start to penetrate, and dividing this by the opposing length H of the walls 11 and 13. As a result, although the reflected electrons 300 reach the insulator 12, the energy of the reflected electrons 300 reaching the insulator 12 can be reduced. Therefore, the period until a discharge due to charging occurs can be extended.

When the reflected electron 300 penetrates between the wall surfaces 15 and 17, the inclination angle of the wall surface 17 that it first collides with is α, and the inclination angle of the wall surface 15 that it next collides with is β. This can be similarly applied to the above cases 1 to 3.

The components into which the reflected electrons 300 emitted by irradiating the sample 101 with the electron beam 200 enter are not limited to the electrostatic lens 214. For example, the reflected electrons 300 may enter the deflector 204. When the charge on the insulator that constitutes the deflector 204 exceeds a certain amount, discharge occurs, disturbing the electric field in space A on the trajectory of the electron beam 200. This affects the electron beam 200, causing a deviation in the trajectory of the electron beam 200. As a result, the drawing accuracy deteriorates.

Therefore, in a modification of the first embodiment, the reflected electrons 300 that have entered the deflector 204 are prevented from reaching the insulator. Or, even if they do reach the insulator, the energy of the reflected electrons 300 is attenuated before they reach the insulator. This is explained in detail below.

FIG. 9 is a diagram for explaining an example of a cross-sectional configuration of a deflector in a modification of the first embodiment and a state in which reflected electrons enter.
Fig. 10 is a top cross-sectional view showing an example of the configuration of a CC cross section of a deflector in a modified example of the first embodiment. In Figs. 9 and 10, a deflector 204 has a plurality of dipole or more electrodes 30 (another example of electrodes), a conductive upper cap 36, a conductive lower cap 34, a holder 38 (connecting member), and a plurality of insulators 32. In the example of Figs. 9 and 10, a case is shown in which the plurality of electrodes 30 are, for example, octupole electrodes.

The electrodes 30 are arranged in the electron beam column 102 and are formed so that their thickness tapers toward the center. In the example of FIG. 9, the electrodes 30 are formed so that both the upper and lower surfaces taper toward the center. However, this is not limited to this. For example, the upper surface may be horizontal, and the lower surface may be configured to form an upward slope toward the center. As shown in FIG. 9 and FIG. 10, the electrodes 30 are arranged symmetrically with respect to the central axis of the orbit of the electron beam 200, with a phase shift. Each of the electrodes 30 is connected to the deflection control circuit 130 via a DAC amplifier (not shown). An individual potential according to the amount of deflection of the electron beam 200 is applied to each electrode 30.

The upper cap 36 is disposed above the electrodes 30 in the electron beam column 102 at a distance. The upper cap 36 has at least one lower surface that faces the upper surfaces of the electrodes 30 at an angle that is not parallel to the upper surfaces of the electrodes 30. The upper cap 36 has a regular octagonal flange when viewed from above. The regular octagonal flange is formed to be, for example, the same size as the cylindrical holder 38 having a regular octagonal cross section. The upper cap 36 is formed so as to cover, for example, the entire holder 38 from above. The lower surface of the upper cap 36 is formed in a tapered shape such that the thickness decreases from the outer periphery to the inner periphery, for example, like the inclined surface of a truncated cone. The upper cap 36 and the holder 38 do not need to be separate parts, and may be integrally formed parts by machining from the same material.

The lower cap 34 is disposed below the electrodes 30 in the electron beam column 102 at a distance. The lower cap 34 has at least one upper surface that faces the lower surfaces of the electrodes 30 at an angle that is not parallel to the lower surfaces of the electrodes 30. The lower cap 34 has a regular octagonal flange when viewed from below. The regular octagonal flange is formed to be, for example, the same size as the cylindrical holder 38 having a regular octagonal cross section. The lower cap 34 is formed so as to cover, for example, the entire holder 38 from below. The upper surface of the lower cap 34 is formed in a tapered shape such that the thickness decreases from the outer periphery to the inner periphery, for example, like the inclined surface of a truncated cone. The lower cap 34 and the holder 38 do not need to be separate parts, and may be integrally formed parts by machining from the same material.

Figure 11 is a top view showing another example of the lower cap in the modified example of the first embodiment. In the example of Figure 10, the lower cap 34 is formed so as to cover the entire cylindrical holder 38 from below, but this is not limited to this. In the example of Figure 11, the lower cap 34 has a regular octagonal outer peripheral frame 37 and, for example, eight protrusions 39 from the outer peripheral frame 37 toward the center. The eight protrusions 39 are formed with the same width size as the multiple electrodes 30 and the same length toward the center. The eight protrusions 39 are arranged in the same phase as the multiple electrodes 30. In this configuration, the lower cap 34 has eight upper surfaces that face the lower surfaces of the multiple electrodes 30 at an angle that is not parallel to them.

In the example of FIG. 10, the upper cap 36 is formed to cover the entire holder 38, which is a cylindrical holder with a regular octagonal cross section, from above, but this is not limited to the above. The example of FIG. 11 corresponds to another example of the upper cap 36 viewed from below. In this case, the upper cap 36, like the lower cap 34, has a regular octagonal outer peripheral frame 37 and, for example, eight protrusions 39 extending from the outer peripheral frame 37 toward the center. The eight protrusions 39 are formed with the same width as the multiple electrodes 30 and the same length toward the center. The eight protrusions 39 of the upper cap 36 are arranged in the same phase as the multiple electrodes 30. In this configuration, the upper cap 36 has eight lower surfaces that face the upper surfaces of the multiple electrodes 30 at angles that are not parallel to them.

In Figures 9 to 11, the holder 38 supports the upper cap 36 and the lower cap 34 on the outer periphery side within the electron beam column 102, and electrically connects the upper cap 36 and the lower cap 34. In addition, openings are formed toward the center of each of the eight faces that make up the outer periphery of the holder 38. The upper cap 36 and the lower cap 34 are connected to a ground potential (GND) via the holder 38. In other words, the upper cap 36 and the lower cap 34 are grounded. Note that the lower cap 34, the upper cap 36, and the holder 38 do not need to be separate parts, and may be parts that are integrally formed by machining from the same material.

9 to 11, the multiple insulators 32 are connected to the holder 38 on the outer periphery side of the holder 38 in the electron beam column 102. The multiple insulators 32 are further connected to corresponding ones of the multiple electrodes 30. Specifically, the electrodes 30 are inserted into the openings of the eight faces constituting the outer periphery of the holder 38. The outer ends of the electrodes 30 are fixed to the corresponding insulators 32. The insulators 32 are fixed to the corresponding faces of the eight faces constituting the outer periphery of the holder 38 from the outer periphery side of the holder 38 so as to close the openings of the eight faces constituting the outer periphery of the holder 38. The multiple insulators 32 insulate the corresponding ones of the multiple electrodes 30 from the holder 38. For this reason, the insulators 32 are arranged to separate the electrodes 30 from the holder 38 so that the electrodes 30 connected to the holder 38 do not come into contact with the holder 38.

9, the electrodes 30 and the lower cap 34 are formed so as to narrow the path of the reflected electrons 300 penetrating between the lower surfaces of the electrodes 30 and at least one upper surface of the lower cap 34 toward the corresponding insulators 32. In other words, the walls 31 and 33 are formed so that the space between the walls 31 and 33 tapers from space A on the trajectory of the electron beam 200 toward the back of the space between the wall 31 (another example of the first wall) which is the lower surface of the electrode 30 and the wall 33 (another example of the second wall) which is the upper surface of the lower cap 34.

Similarly, the electrodes 30 and the upper cap 36 are formed so as to narrow the path of the reflected electrons 300 penetrating between the upper surfaces of the electrodes 30 and at least one lower surface of the upper cap 36 toward the corresponding insulator 32. In other words, the walls 35 and 37 are formed so that the space between the walls 35 and 37 tapers from space A on the trajectory of the electron beam 200 toward the back of the space between the wall 37 (another example of the first wall) which is the lower surface of the upper cap 36 and the wall 35 (another example of the second wall) which is the upper surface of the electrode 30.

As in the case of the electrostatic lens 214 described above, the configurations of cases 1 and 2 described above are suitable for preventing the reflected electrons 300 that have entered the space between the wall surfaces 31 and 33 from reaching the insulator 32. Also, even if the reflected electrons 300 do reach the insulator 32, the configuration of case 3 described above is suitable for attenuating their energy.

In case 1, the wall surfaces 31 and 33 are arranged so that the inclination angle α of the wall surface 31, with which the reflected electron 300 first collides after penetrating between the wall surfaces 31 and 33, is greater than the incidence angle θ of the reflected electron 300. This makes it possible to prevent the reflected electron 300 from reaching the insulator 32.

In case 2, the inclination angle α of the wall surface 31 where the reflected electron 300 first collides after penetrating between the wall surfaces 31 and 33 is smaller than the incidence angle θ of the reflected electron 300. In FIG. 9, the distance B between the wall surfaces 31 and 33 where the reflected electron 300 starts penetrating and the opposing length H of the wall surfaces 31 and 33 are shown.

In FIG. 9, the parameters are defined as follows:
The distance between the wall surfaces 31 and 33 where the reflected electrons 300 start to penetrate (opening width): B
Length (height) of opposing wall surfaces 31 and 33: H
The inclination angle of the wall surface 31 that first collides is α
The inclination angle of the wall surface 33 that will collide next is β

In case 2, as described above, it is sufficient to satisfy formula (4). When (α+β) takes the minimum value within the range that satisfies formula (4), the total number of reflections 2θ/(α+β) is maximized. As a result, after a total number of reflections of 2θ/(α+β), the reflected electrons 300 are returned to the original space. This makes it possible to prevent the reflected electrons 300 from reaching the insulator 12.

In case 3, the inclination angle α of the wall surface 31 with which the reflected electron 300 first collides after penetrating between the wall surfaces 31 and 33 is smaller than the incidence angle θ of the reflected electron 300. In case 3, as described above, the relationship satisfies formula (5).

In this relationship, r>R, and the trajectory of the reflected electrons 300 exceeds the height H of the space between the wall surfaces 31 and 33. However, due to the wall surfaces 31 and 33 having the inclination angles α and β, the number of reflections (number of collisions) of the reflected electrons 300 is greater than in the space of parallel plates. The reflected electrons 300 attenuate their energy with each reflection (collision). Therefore, by increasing the number of reflections (number of collisions), the energy of the reflected electrons 300 that reach the insulator 32 can be reduced. Therefore, in case 3, the period until discharge due to charging occurs can be extended.

When the reflected electron 300 penetrates between the wall surfaces 35 and 37, the inclination angle of the wall surface 37 that it first collides with is α, and the inclination angle of the wall surface 35 that it next collides with is β. This can be similarly applied to the above cases 1 to 3.

In the above example, the reflected electrons 300 travel through a space that tapers in, for example, the x direction perpendicular to the direction of the central axis of the orbit of the electron beam 200 (-z direction), but the present invention is not limited to this.

FIG. 12 is a diagram for explaining an example of a cross-sectional configuration of the limiting aperture mechanism in the first embodiment and the state of intrusion of reflected electrons. In FIG.
13 is a top view of an example of the configuration of the limiting aperture mechanism in the first embodiment. In FIG. 12 and FIG. 13, the limiting aperture mechanism 212 has a conductive aperture substrate 21, a conductive aperture holder 20, a conductive ring 26, a ring holder 28 (connecting member), and an insulator 22. The limiting aperture substrate 21 is formed, for example, in a disk shape. The limiting aperture substrate 21 has a circular opening 4 in the center for the electron beam 200 to pass through. The aperture holder 20 is formed, for example, in a ring shape. The insulator 22 is formed, for example, in a ring shape. The ring holder 28 is formed, for example, in a ring shape. The aperture substrate 21, the aperture holder 20, the ring 26, the ring holder 28, and the insulator 22 are formed axially symmetrically with respect to the central axis of the orbit of the electron beam 200. In FIG. 12, the right side portion of the cross section is shown. The left side portion of the cross section is omitted from the illustration.

The aperture substrate 21 is disposed within the electron beam column 102, and as shown in Figures 12 and 13, blocks electrons from the electron beam 200 that miss the aperture 3. It is also suitable for a desired potential to be applied to the aperture substrate 21 from a power supply device (not shown).

The aperture holder 20 is connected to the outer periphery of the upper surface of the aperture substrate 21 and is formed so that its thickness tapers downward. The aperture holder 20 is electrically connected to the aperture substrate 21.

The ring 26 is disposed within the electron beam column 102 at a distance from the inner circumference of the aperture holder 20 and has an outer circumferential surface that faces the inner circumference of the aperture holder 20 at an angle that is not parallel to the inner circumference of the aperture holder 20.

The ring holder 28 is connected to the ring 26 above the ring 26 to support the ring 26. The ring holder 28 is electrically connected to the ring 26. It is preferable that the diameter size of the inner circumferential surface of the ring holder 28 is the same as the inner diameter of the ring 26. It is also preferable that the diameter size of the outer circumferential surface of the ring holder 28 is the same as the outer diameter of the insulator 22. The ring 26 is connected to a ground potential (GND) via the ring holder 28. In other words, the ring 26 is grounded. It is also preferable that the ring holder 28 and the ring 26 are formed integrally.

The insulator 22 is disposed between the ring holder 28 and the aperture holder 20 in the electron beam column 102, and provides insulation between the ring holder 28 and the aperture holder 20. In other words, the ring 26 and the insulator 22 are connected by the ring holder 28. The ring holder 28 functions as a connecting member that connects the ring 26 and the insulator 22.

Reflected electrons 300 are emitted by irradiating the aperture substrate 21 (another example of an object) with the electron beam 200 that has missed the opening 3. For example, the electron beam 200 may be blanked by being deflected by a deflector (not shown) upstream of the aperture substrate 21 in the electron beam trajectory. Alternatively, at least a part of the electron beam 200 may miss the opening 3 when a deviation occurs in the central axis of the electron beam trajectory.
Here, for example, without the ring 26, the insulator 22 is directly exposed to the space A on the trajectory of the electron beam 200, and the reflected electrons 300 reach the insulator 22. As a result, the insulator 22 becomes charged. Therefore, in order to prevent the insulator 22 from becoming charged, the ring 26 is disposed inside the insulator 22 so as to hide the insulator 22 from the space A. The ring 26 functions as a shielding member.

The limiting aperture substrate 21 and the aperture holder 20 are insulated from the ring 26 by the insulator 22. In other words, the wall surface 23 (an example of a first wall surface) of the aperture holder 20 on the ring 26 side and the wall surface 25 (an example of a second wall surface) of the ring 26 on the aperture holder 20 side are arranged so as not to contact each other. In addition, the walls are electrically insulated from each other by the insulator 22.

Here, as described above, the electron beam 200 irradiates the limiting aperture substrate 21 (another example of an object) to emit reflected electrons 300. The emitted reflected electrons 300 enter the space between the aperture holder 20 and the ring 26 at a predetermined angle of incidence. At that time, when the opposing surfaces of the aperture holder 20 and the ring 26 are arranged parallel to each other, the reflected electrons 300 move upward while repeatedly colliding with the wall surface through the space between the aperture holder 20 and the ring 26 as a passage. Then, the reflected electrons 300 reach the insulator 22 and charge the insulator 22. Then, when the charge amount of the insulator 22 exceeds a certain amount, it discharges, disturbing the electric field in the space A on the trajectory of the electron beam 200. This affects the electron beam 200, causing a deviation in the trajectory of the electron beam 200. As a result, the drawing accuracy is deteriorated.

Therefore, in the first embodiment, the reflected electrons 300 that have entered the space between the aperture holder 20 and the ring 26 are prevented from reaching the insulator 22. Or, even if they do reach the insulator, the energy of the reflected electrons 300 is attenuated before they reach the insulator 22.

12, the aperture holder 20 and the ring 26 are formed so as to narrow the passage of the reflected electrons 300 penetrating between the inner peripheral surface of the aperture holder 20 and the outer peripheral surface of the ring 26 toward the insulator 22. Specifically, the wall surface 23 (another example of the first wall surface) of the aperture holder 20 and the wall surface 25 (another example of the second wall surface) of the ring 26 are arranged in the electron beam column 102, and the surfaces face each other at a non-parallel angle without contacting each other. The surface with a wider distance between the facing surfaces is exposed to the space A on the trajectory of the electron beam 200. The wall surface 23 is formed in a tapered shape with an inclination angle α with respect to the height direction (z direction). The wall surface 25 is formed in a tapered shape with an inclination angle β with respect to the height direction. In other words, the wall surfaces 23 and 25 are formed so that the space between the wall surfaces 23 and 25 tapers from the space A on the trajectory of the electron beam 200 toward the back of the space between the wall surfaces 23 and 25. Figure 12 shows a case where the space between the walls 23 and 25 tapers in the z direction.

The insulator 22 is disposed within the electron beam column 102 and is disposed on the side where the distance between the opposing wall surfaces 23, 25 is narrowed. The insulator 22 electrically insulates the wall surfaces 23, 25 on the side where the distance between the opposing wall surfaces 23, 25 is narrowed. The insulator 22 is exposed to the space that continues from within the electron beam column 102 through the space between the wall surfaces 23, 25.

The reflected electrons 300 emitted by irradiating the limiting aperture substrate 21 with the electron beam 200 penetrate between the opposing wall surfaces 23 and 25 at an incident angle θ from the side where the distance between the opposing wall surfaces 23 and 25 is wider. In the first embodiment, as shown in FIG. 12, the wall surfaces 23 and 25 are arranged so as to narrow the path of the reflected electrons 300 between the wall surfaces 23 and 25 toward the insulator 22. The reflected electrons 300 that penetrate proceed through the space between the wall surfaces 23 and 25 while colliding with the wall surfaces 23 and 25. Every time the reflected electrons 300 collide with the wall surface 23 (or the wall surface 25), the reflected electrons are emitted radially from the wall surface 23 (or the wall surface 25). The example in FIG. 12 shows the trajectory of the reflected electrons 300 that are emitted in the direction of the largest energy where the angle of incidence and the angle of reflection are the same with respect to the wall surface 23 (or the wall surface 25) among the reflected electrons emitted radially from the collision point. The reflected electrons emitted in other directions have low energy, and as they collide repeatedly, their energy becomes even smaller, so their effect on charging is negligible. Therefore, we will omit the explanation here.

Here, in order to prevent the reflected electrons 300 that have entered the space between the wall surfaces 23 and 25 from reaching the insulator 22, the wall surfaces 23 and 25 are arranged so as to satisfy the relationship of cases 1 and 2 described above. Also, even if the reflected electrons 300 do reach the insulator 22, in order to attenuate their energy, the wall surfaces 23 and 25 are arranged so as to satisfy the relationship of case 3 described above.

As described above, according to the first embodiment, charging of the insulator 12 (22) in the electron beam column 102 can be suppressed or reduced. This allows for highly accurate beam irradiation. As a result, highly accurate drawing can be achieved.

The above describes the embodiment with reference to specific examples. However, the present invention is not limited to these specific examples. In the above example, a single electron beam is used, but the present invention is not limited to this. An irradiation device (drawing device) using multiple electron beams may also be used.

In addition, although the description of the device configuration, control method, and other parts that are not directly necessary for the explanation of the present invention have been omitted, the required device configuration and control method can be appropriately selected and used. For example, although the description of the control unit configuration that controls the drawing device 100 has been omitted, it goes without saying that the required control unit configuration can be appropriately selected and used.

In addition, all electron beam irradiation devices that incorporate the elements of the present invention and that can be appropriately modified by a person skilled in the art are included within the scope of the present invention.

3, 4, 5, 6, 7 Opening 10 Electrode 11, 13, 15, 17 Wall surface 12 Insulator 14 Lower cap 16 Upper cap 18 Holder 20 Aperture holder 21 Limiting aperture substrate 22 Insulator 23, 25 Wall surface 26 Ring 28 Ring holder 30 Electrode 31, 33, 35, 37 Wall surface 32 Insulator 34 Lower cap 36 Upper cap 38 Holder 100 Drawing device 101 Sample 102 Electron beam column 103 Drawing chamber 105 Stage 110 Control computer 112 Memory 120 Bus 124 Lens control circuit 130 Deflection control circuit 140 Storage device 150 Drawing mechanism 160 Control system circuit 201 Electron gun 202 Illumination lens 204 Deflector 206 Objective lens 212 Limiting aperture mechanism 214 Electrostatic lens 300 Reflected electrons

Claims (10)

an electron beam column for irradiating a sample with an electron beam;
an electrode disposed in the electron beam column, formed axially symmetrically with respect to a central axis of the orbit of the electron beam, having an opening at its center through which the electron beam passes, and having a thickness tapering from an outer periphery toward the opening;
a conductive cap disposed in the electron beam column and spaced apart from the electrode, formed axially symmetrically with respect to a central axis of an electron beam trajectory, having an opening at its center through which the electron beam passes, and having a surface opposed to a surface of the electrode at an angle not parallel to the surface of the electrode;
a conductive holder that connects the cap to an outer periphery of the cap within the electron beam column;
an insulator disposed between the electrode and the holder in the electron beam column to insulate the electrode from the holder;
Equipped with
An electron beam irradiation device characterized in that the electrode and the cap are formed so as to narrow a path of reflected electrons emitted when the electron beam is irradiated onto a sample, which penetrates between a surface of the electrode and a surface of the cap, toward the insulator. The electron beam irradiation device according to claim 1, characterized in that the conductive cap and the holder are integrally formed. The conductive cap is
a conductive lower cap disposed within the electron beam column below the electrode and spaced apart, the lower cap having a central opening through which the electron beam passes and an upper surface opposed to and at a non-parallel angle to a lower surface of the electrode;
2. The electron beam irradiation device according to claim 1, further comprising: a conductive upper cap disposed above the electrode in the electron beam column at a distance, the conductive upper cap having an opening at a central portion through which the electron beam passes and a lower surface facing the upper surface of the electrode at an angle that is not parallel to the upper surface of the electrode. As the electrodes, a plurality of electrodes having two or more poles each having a thickness tapering toward the center are used,
the cap is disposed in the electron beam column at a distance from the electrodes, is formed axially symmetrical with respect to a central axis of the electron beam, and has at least one surface opposed to the electrodes at an angle that is not parallel to the surfaces of the electrodes;
As the insulator, a plurality of insulators are used in the electron beam column, the insulators being connected to the holder on the outer circumferential side of the holder and connected to corresponding ones of the plurality of electrodes, and insulating the corresponding ones of the plurality of electrodes from the holder,
2. The electron beam irradiation device according to claim 1, wherein the plurality of electrodes and the cap are formed so as to narrow a path of reflected electrons emitted when the electron beam is irradiated onto a sample, the path entering between the surfaces of the plurality of electrodes and the at least one surface of the cap, toward the insulator. The cap is
a conductive upper cap disposed in the electron beam column in spaced relation above the plurality of electrodes and having at least one lower surface opposed at a non-parallel angle to upper surfaces of the plurality of electrodes;
a conductive lower cap disposed in the electron beam column in a spaced relationship below the plurality of electrodes and having at least one upper surface opposed at a non-parallel angle to lower surfaces of the plurality of electrodes;
5. The electron beam irradiation apparatus according to claim 4, further comprising: an electron beam column for irradiating a sample with an electron beam;
a conductive aperture substrate disposed within the electron beam column, formed axially symmetrically with respect to a central axis of the orbit of the electron beam, having an aperture formed at its center through which the electron beam passes, and blocking electrons of the electron beam that deviate from the aperture;
a conductive aperture holder connected to an outer periphery of an upper surface of the aperture substrate, formed symmetrically with respect to a central axis of the orbit of the electron beam, and formed so that a thickness thereof decreases downward;
a conductive ring formed in the electron beam column symmetrically with respect to a central axis of the orbit of the electron beam, disposed on an inner peripheral side of the aperture holder at a distance, and having an outer peripheral surface that faces the inner peripheral surface of the aperture holder at an angle that is not parallel to the inner peripheral surface of the aperture holder;
a ring holder that supports the ring above the ring;
an insulator disposed between the ring holder and the aperture holder in the electron beam column to provide insulation between the ring holder and the aperture holder;
Equipped with
An electron beam irradiation device characterized in that the aperture holder and the ring are formed so as to narrow the path of reflected electrons emitted when the electron beam is irradiated onto the aperture substrate, which penetrates between the inner surface of the aperture holder and the outer surface of the ring, toward the insulator. The electron beam irradiation device according to claim 1, 4 or 6, characterized in that the path of the reflected electrons is formed from the opposing first and second wall surfaces toward the insulator and is inclined at a certain angle so as to narrow the path of the reflected electrons. a path of the reflected electrons is formed by first and second wall surfaces facing each other, and an inclination angle of a wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is smaller than an incidence angle θ of the reflected electrons,
7. The electron beam irradiation device according to claim 1, 4 or 6, wherein the first and second wall surfaces are arranged so that the sum of the tangent of the inclination angle α of the first wall surface and the tangent of the inclination angle β of the second wall surface is greater than the difference obtained by subtracting the cosine of the incidence angle θ of the reflected electron from 1, multiplying the difference by the distance B between the first and second wall surfaces at which the reflected electron begins to penetrate, and dividing the result by the opposing length H of the first and second wall surfaces. The electron beam irradiation device according to claim 1, 4 or 6, characterized in that the path of the reflected electrons is formed by opposing first and second wall surfaces, and the first and second wall surfaces are arranged so that the inclination angle of the wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is equal to or greater than the incidence angle θ of the reflected electrons. a path of the reflected electrons is formed by first and second wall surfaces facing each other, and an inclination angle of a wall surface with which the reflected electrons first collide after penetrating between the first and second wall surfaces is smaller than an incidence angle θ of the reflected electrons,
7. The electron beam irradiation device according to claim 1, 4 or 6, wherein the first and second wall surfaces are arranged so that the sum of the tangent of the inclination angle α of the first wall surface and the tangent of the inclination angle β of the second wall surface is equal to or smaller than the difference obtained by subtracting the cosine of the incidence angle θ of the reflected electron from 1, multiplying the difference by the distance B between the first and second wall surfaces at which the reflected electron begins to penetrate, and dividing the result by the opposing length H of the first and second wall surfaces.

Images