JP2855066B2 - Charged particle beam intensity distribution measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the intensity distribution of a charged particle beam in a vacuum, and more particularly to a monitor structure thereof.

[0002]

2. Description of the Related Art Whether a charged particle beam such as an electron beam emitted from an electron gun is irradiated at a predetermined position with a predetermined intensity has an important meaning in evaluating the performance of the electron gun and the like. In particular, the intensity distribution of the charged particle beam is particularly important in the above-described performance evaluation because the charged particle beam spreads around a predetermined position and becomes so-called blurred, which affects resolution, resolution, and the like. Therefore, an apparatus for measuring the intensity distribution of the charged particle beam has been conventionally used.

FIGS. 6A and 6B schematically show a conventional apparatus for measuring the intensity distribution of a charged particle beam in a vacuum. FIG. 6A is a plan sectional view, and FIG. 6B is a front sectional view. The charged particle beam travels in the vacuum chamber 10 in the direction of arrow A in FIG. 6B, and in FIG. In practice, the charged particle beam passes through the region having a certain spread from the center 12 of the charged particle beam. This passage area is shown as a charged particle beam passage area 14 in the figure. This apparatus measures the intensity distribution of the charged particle beam in the charged particle beam passage area 14 and further measures the absolute intensity of the charged particle beam in the passage area 14 by integrating the intensity distribution.

[0004] The intensity distribution in the charged particle beam passage area 14 is a two-dimensional distribution, and data in two directions is required to measure this. That is, data on the directions of arrows X and Y shown in FIG. 6 is required.

For this reason, in the conventional apparatus,
Monitors 18x and 18y are provided for each direction. One wire 16x is stretched over one monitor 18x. Although not shown in this wire 16x,
A galvanometer capable of measuring a current flowing through the wire is connected. The monitor 18x is connected to a hydraulic actuator 24 as a drive mechanism via an arm 20 and a moving table 22.
The wire 16x is connected to the charged particle beam passage area 14 by expansion and contraction of the hydraulic actuator 24.
Can move forward and backward. This monitor 18
A telescopic bellows 26 is provided corresponding to the advance and retreat of x.

[0006] As shown in FIG. 6 (b), the moving table 22 moves on a slide rail 28. by this,
The moving table is smoothly moved.

When a charged particle beam collides with the wire 16x,
If the energy of the charged particle beam at this time is low, the charged particle beam enters the wire 16x, and therefore, current flows through the wire 16x. Also, the energy of the charged particle beam is about 20
When it exceeds MeV, the charged particle beam becomes a wire 16x
, Secondary electrons are emitted and the wire 16x
Current flows through Thus, the value of the current flowing through the wire 16x can be detected, and the intensity of the charged particle beam can be measured.

As described above, in the case of one wire 16x, the intensity of the particle beam of the entire chord that crosses the charged particle beam passage area 14 is measured. In order to measure the two-dimensional intensity distribution, measurement in two directions is necessary as described above. In the conventional device, in order to measure in the direction of arrow Y in the drawing, the monitor is orthogonal to the monitor 18x. The monitor 18y is provided in a direction in which the wire 16y extends. The configuration of the monitor 18y and its driving mechanism is exactly the same as the configuration of the monitor 18x and its driving mechanism, and only the arrangement thereof is different. Is omitted. As described above, the strength of the charged particle beam is detected by the wires stretched over each of the two monitors movable in two directions, and the strength of the charged particle beam is analyzed. It is possible to measure the distribution.

[0009]

As described above, the conventional apparatus has two monitors, and therefore, it is necessary to provide a drive mechanism for each of them. Therefore, there is a problem that the installation place is required and the apparatus becomes large. In addition, there is a problem that the cost is increased due to having two sets of drive mechanisms. Further, there is a problem that it is necessary to separately measure the intensity in two directions, and it takes time for the measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a charged particle beam intensity distribution measuring apparatus which has a small number of parts by a simple driving mechanism, is small, and has a short measuring time. The purpose is to:

[0011]

In order to achieve the above-mentioned object, a charged particle intensity distribution measuring apparatus according to claim 1 is provided by detecting an electric current generated in a wire which is attached to a monitor and receives a particle beam. In the apparatus according to the present invention, the wire may include one first wire stretched in a direction intersecting the moving direction of the monitor, and the first wire crossing the first wire on the same monitor as the first wire. And at least one second wire stretched at a position where the second wire extends.

In the apparatus according to the second aspect of the present invention, a single monitor is provided in the vacuum chamber,
The wire is a single first wire stretched in a direction intersecting the moving direction of the monitor, and at least a first wire stretched in a direction crossing the first wire on the same monitor as the first wire. Consisting of one second wire, the monitor drive mechanism has a single control axis.

[0013] In the apparatus according to the third aspect of the present invention, the first wire of the apparatus according to the first or second aspect of the present invention is stretched in a direction perpendicular to the moving direction of the monitor. A plurality of the second wires are extended in a moving direction of the monitor.

Further, in the device according to the fourth aspect of the present invention, the second wire of the device according to the first or second aspect of the present invention is stretched in a direction intersecting the direction of movement of the monitor. One wire.

[0015] In the apparatus according to the fifth aspect of the present invention, the first wire and the second wire of the apparatus according to the fourth aspect have an inclination of 45 ° with respect to the moving direction of the monitor. And are arranged at 90 ° to each other.

In the apparatus according to the present invention, the monitor driving mechanism of the apparatus according to the present invention controls the monitor in a direction orthogonal to the direction of the charged particle beam. It goes straight.

In the apparatus according to the present invention, the monitor driving mechanism of the apparatus according to any one of the first to fifth aspects rotates in a plane orthogonal to the direction of the charged particle beam. The monitor is disposed at the tip of the arm, and the monitor is moved forward and backward with respect to the charged particle beam passage area by rotating the arm.

[0018]

The present invention has the above-described configuration, and the number of monitors can be reduced by extending a wire crossing one monitor. Further, by configuring the drive mechanism of the monitor with one mechanism having a single control axis, the apparatus is simplified. Further, when the orthogonal coordinate system having the orthogonal direction as two axes and the extending direction of the first and second wires are made to match, the processing of the detection result can be simplified. Further, when the first wire and the second wire are each constituted by one wire, the device is simplified. Further, each of the first and second wires is 90
In the case of intersecting at degrees, the processing of the detection result, in which an orthogonal coordinate system with the direction of these wires as an axis, can be simplified. Further, by setting the direction of movement of the monitor to the direction orthogonal to the charged particle beam, the movable stroke amount can be minimized. Further, by providing the monitor at the tip of the rotating arm, the drive mechanism can be further arranged in a small space.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of a charged particle beam intensity distribution measuring apparatus according to the present invention. FIG. 1A is a plan sectional view, and FIG. 1B is a front sectional view. The charged particle beam extends along the direction of arrow A (see FIG. 1B).
The light enters the vacuum chamber 30 from above. The incident charged particle beam is distributed with a predetermined spread around the center point 12 as described above, and this region is shown as a charged particle beam passage region 14 in the figure. Since the region 14 is considered to have no anisotropy in a plane orthogonal to the direction of incidence of the charged particle beam, it becomes a circular region as shown in the figure.

In the vacuum chamber 30, first and second wires 36 that can advance and retreat into the charged particle beam passage area 14 are provided.
a and 36b are stretched over one monitor 38 having a frame shape. The first wire 36a extends in the direction perpendicular to the direction C of movement of the monitor 38, and the second wire 36b extends 90 degrees in the direction in which the first wire 36a extends.
A plurality are stretched in the direction crossing °. Therefore,
The second wire 36b is stretched in the same direction as the moving direction C of the monitor 38. The first wire 36a is extended on the upstream side in the incident direction of the charged particle beam with respect to the second wire 36b, and these wires are extended at positions where they do not contact each other. Further, the resolution of the analysis in the direction in which the second wires 36b are stretched determines the direction in which the second wires 36b are arranged, that is, the direction perpendicular to the direction in which the monitor 38 moves forward and backward. Therefore, the number of the second wires 36b is determined by the required resolution.

The monitor 38 is fixedly supported at one time on the arm 20, and the arm 20 is fixedly disposed at one time on the hydraulic actuator 24 via the movable base 22. The moving table 22 slides on the slide guide 28 according to the expansion and contraction of the hydraulic actuator. Therefore, this moving table 2
The arm 20 fixed to 2 and the monitor 38 advance and retreat in the direction of arrow C according to the expansion and contraction of the hydraulic actuator 24. Then, the stretched wires 36a and 36b are advanced and retracted into the charged particle beam passage area. In addition, the bellows 26 advances and retreats as the actuator 24 expands and contracts, so that the confidentiality in the vacuum chamber 30 is maintained.

In the measurement, the charged particle beam passage area 1
The first wire 36a is sequentially positioned at a position where the monitor 4 is divided into a predetermined number in the moving direction of the monitor 38, and the intensity of the charged particle beam is measured each time. For this purpose, the hydraulic actuator 24
, The monitor 38 is sequentially moved forward and backward, and the first wire 36a is positioned at a predetermined position.

Regarding the detection by the second wire 36b,
What is necessary is just to detect at the point in time when the second wire has covered the entire charged particle beam passage area 14. Therefore, the detection may be performed in parallel with the current detection of the first wire 36a at a position that satisfies the above condition among the measurement positions of the first wire 36a.
For example, the first wire 36a is connected to the center point 12 of the charged particle beam.
It is sufficient to detect the current of the second wire 36b when the second wire 36b is at a position where the second wire 36b has a length corresponding to the diameter of the charged particle beam passage area 14, and the monitor 38 has a minimum size. It will be.

For the measurement of the current generated in the first and second wires 36a and 36b, a galvanometer circuit may be provided for each of the wires, and the measurement may be performed independently. Measurement may be performed.

As described above, by disposing the first wire 36a on the upstream side of the second wire 36b,
Although a part of the wire 36b becomes a shadow of the first wire 36a,
Since the charged particle beam having a high energy of about 20 MeV penetrates the first wire 36a, there is almost no problem in the measurement.

As described above, the resolution in the direction orthogonal to the monitor moving direction is determined by the number of the second wires 36b, but the resolution in the monitor moving direction is the first wire 36a.
Is determined by the number of measurement positions. Therefore, usually, the number of measurement positions of the first wire 36a and the second wire 36b
It is preferable that the number is equal.

As described above, according to this embodiment, the intensity distribution can be measured by one set, instead of providing two sets of monitors and a mechanism for driving the monitors as in the conventional apparatus.
Therefore, the number of parts can be reduced, and the size of the apparatus can be reduced. Also, the first wire 36a and the second wire 36b
Since they are arranged so as to intersect at 0 °, the detection result can be directly handled as an orthogonal coordinate system when analyzing the intensity distribution, so that the arithmetic processing is simplified. FIG. 2 shows a second embodiment of the charged particle beam intensity distribution measuring apparatus according to the present invention.
The configuration of the present embodiment is different from the first embodiment in that the monitor and the first
The configuration of the second wire is different from that of the first embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

The first wire 46 is connected to the monitor 48 of this embodiment.
a and the second wire 46b are stretched one by one.
The first wire 46a is arranged to be inclined 45 ° counterclockwise with respect to the monitor moving direction, and the second wire 46b is arranged to be inclined 45 ° clockwise. Therefore, the two wires 46a and 46b are arranged at positions where they intersect at 90 °. However, at this time, the two wires 46a and 46b are arranged so as not to be in contact with each other, and the first wire 46a is arranged on the upstream side in the incident direction of the charged particle beam as in the first embodiment.

In this embodiment, the monitor 48 is expanded and contracted by the hydraulic actuator 24 in the same manner as in the first embodiment.
And the first and second wires 46a and 46b are advanced and retracted with respect to the charged particle beam passage area 14. At this time, by performing measurement at a plurality of predetermined locations in the charged particle beam passage area 14, the intensity distribution of the charged particle beam can be measured. In this embodiment, the resolution of the intensity distribution is determined by the number of fixed positions of the monitor.

As for the current detection circuit for the current flowing through the wire, one current detection circuit may be provided for each wire, and one current detection circuit may be switched and used.

The time required for the measurement depends on the number of measurement positions, but is shorter than or equal to that of the first embodiment. For example, when an independent galvanic circuit is provided for each wire, if the number of positions to be measured by stopping monitoring is equal, the measurement time is the same in both the first embodiment and the second embodiment. . However, in the case where the current detection circuit is one circuit for each of the first wire and the second wire, that is, two circuits in total, the first embodiment detects the current of the second wire at a certain measurement position. Must be performed as many times as the number of wires, so that the measurement time becomes longer. However, the second embodiment is the same as the case described above.

As described above, in the present embodiment, the apparatus can be simplified by using one first wire and one second wire. Further, the detection time can be set to be substantially the same as that of the first embodiment.

FIG. 3 is a sectional view of a third embodiment according to the present invention. The difference from the above-described embodiment is that the incident direction of the charged particle beam is from the side as shown by arrow D, so that the moving direction of the monitor is up and down as shown by arrow E. Was replaced by a ball screw instead of a hydraulic actuator.
Other configurations are the same as those of the above-described embodiment, and the same reference numerals are given and the description is omitted. In the figure, the monitor has the same configuration as the second embodiment,
This can be changed from the monitor of the first embodiment.

As described above, in this embodiment, the monitor 4
8 is the vertical direction E, and a drive mechanism using ball screws 52 and 54 is provided to move the monitor 48 forward and backward. A drive motor 56 is connected to the male screw 54 via a gear box 58 to rotate the male screw 54 of the ball screw. The drive motor 56 is a motor whose rotation angle is easily controlled, such as a step motor, and the rotation is transmitted to the gear box 58. In the gear box 58, the rotation direction of the bevel gear or the hypoid gear is set to 9
A transmission mechanism for changing 0 ° is provided, which changes the rotation direction of the drive motor 56. The rotation of the male screw 54 raises and lowers the female screw 52 screwed with the male screw 54. The female screw 52 is fixed to the moving table 50, and the arm 20 supporting the monitor is also fixed to the moving table 50. Therefore, the monitor 48 moves up and down by the rotation of the drive motor 56.

The current detection is the same as in the above-described two embodiments, and will not be described.

FIG. 4 is an inverted view of the third embodiment shown in FIG.

FIG. 5 is a sectional view of a fourth embodiment according to the present invention. The feature of this embodiment is that the monitor does not advance or retreat as in the above-described embodiments, but rotates around a predetermined point and advances and retreats to the charged particle beam passage area 14. In the figure, the monitor 38 having the same configuration as that of the first embodiment is shown, but it is also possible to adopt the same configuration as the monitor 48 shown in the second embodiment and the like. The monitor 38 is fixed to the tip of an arm 64 that rotates about a support shaft 66. The arm 64 is rotatable in the direction of arrow F by a drive mechanism (not shown), and this rotation causes the monitor 38 to move the charged particle beam passage area 14.
Can be positioned at a predetermined position.

As described above, in order to move the monitor 38 forward and backward by the rotation, the shapes of the vacuum chamber 60 and the bellows 62 are made different from those of the above-described embodiment. As shown in FIG. 5, the vacuum chamber 60 has a configuration in which one side of an oval is opened, and a bellows 62 is provided in this part. In the case of the present embodiment, since there is no reciprocating portion in the drive mechanism, the outer shape of the device can be reduced.

[0040]

The present invention has the above-described configuration, and the number of monitors can be reduced by extending a wire crossing one monitor. In addition, since the drive mechanism is constituted by one mechanism by using one monitor, the apparatus is simplified. Further, when the orthogonal coordinate system having the orthogonal direction as two axes and the extending direction of the first and second wires are made to match, the processing of the detection result can be simplified. Further, when the first wire and the second wire are each constituted by one wire, a device such as a detection circuit is simplified. Further, when each of the first wire and the second wire intersect at 90 °, processing of a detection result for setting an orthogonal coordinate system having the directions of these wires as axes can be simplified. Further, by setting the direction of movement of the monitor to the direction orthogonal to the charged particle beam, the movable stroke amount can be minimized. Further, by providing the monitor at the tip of the rotating arm, the drive mechanism can be further arranged in a small space.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a charged particle beam intensity distribution measuring apparatus according to the present invention.

FIG. 2 is a diagram showing the configuration of a second embodiment of the charged particle beam intensity distribution measuring apparatus according to the present invention.

FIG. 3 is a diagram showing the configuration of a third embodiment of the charged particle beam intensity distribution measuring apparatus according to the present invention.

FIG. 4 is a diagram showing an example in which the apparatus of the third embodiment is arranged upside down.

FIG. 5 is a diagram showing a configuration of a fourth embodiment of a charged particle beam intensity distribution measuring apparatus according to the present invention.

FIG. 6 is a diagram showing a configuration of a conventional charged particle beam intensity distribution measuring device.

[Explanation of symbols]

 12 Charged particle beam center point 14 Charged particle beam passage area 14 24 Hydraulic actuator 30, 60 Vacuum tank 38, 48 Monitor 36a, 46a First wire 36b, 46b Second wire 52 Ball screw (female screw) 54 Ball screw (male screw)

Claims (7)

(57) [Claims] 1. A vacuum chamber including a particle beam passage area through which a charged particle beam passes, a monitor having a wire on which a current is generated by receiving the particle beam, and moving the monitor forward and backward with respect to the electron beam passage area; In a charged particle beam intensity distribution measuring device that has a monitor driving mechanism that positions the wire at a plurality of measurement positions in this region and measures the intensity distribution of a cross section of the particle beam passing region, the wire is moved in a moving direction of the monitor. A charge having one first wire stretched in a crossing direction and at least one second wire stretched at a position crossing the first wire on the same monitor as the first wire. Particle beam intensity distribution measuring device. 2. A vacuum chamber including a particle beam passage region through which a charged particle beam passes, a monitor having a wire on which a current is generated by receiving the particle beam, and a monitor moving back and forth with respect to the electron beam passage region; In a charged particle beam intensity distribution measuring device that has a monitor driving mechanism that positions the wire at a plurality of measurement positions in this region and measures the intensity distribution of a cross section of the particle beam passing region, a single monitor is provided in the vacuum chamber. The first wire is provided on the same monitor as the first wire, and the first wire is stretched in a direction crossing the first wire. A charged particle beam intensity distribution measuring device, comprising at least one second wire provided, wherein the monitor driving mechanism has a single control axis. 3. The charged particle beam intensity distribution measuring device according to claim 1, wherein the first wire is stretched in a direction perpendicular to a moving direction of the monitor, and the second wire is moved in the moving direction of the monitor. A charged particle beam intensity distribution measuring device characterized by being extended in a plurality of directions. 4. The charged particle beam intensity distribution measuring device according to claim 1, wherein the second wire is a single wire stretched in a direction intersecting a moving direction of the monitor. Charged particle beam intensity distribution measuring device. 5. The charged particle beam intensity distribution measuring device according to claim 4, wherein the first wire and the second wire are arranged at an inclination of 45 ° with respect to the direction of movement of the monitor, and are arranged at 90 ° to each other. A charged particle beam intensity distribution measuring device characterized by crossing. 6. The charged particle beam intensity distribution measuring device according to claim 1, wherein the monitor driving mechanism moves the monitor straight in a direction orthogonal to a direction of the charged particle beam. Charged particle beam intensity distribution measuring device. 7. The charged particle beam intensity distribution measuring device according to claim 1, wherein the monitor driving mechanism has an arm that rotates in a plane orthogonal to the direction of the charged particle beam, The charged particle beam intensity distribution measuring device, wherein the monitor is arranged at a tip of the arm, and the monitor is moved forward and backward with respect to a charged particle beam passage area by rotating the arm.