JPH026084A - Electron beam controller - Google Patents

Abstract

PURPOSE:To improve the accuracy of table position correction and to extend the life of a marker by forming the marker of a metallic member processed with many holes and detecting the positional deviation of an electron beam in accordance with the number of the holes scanned by the electron beam. CONSTITUTION:The marker 8 which is provided on a table 7 and detects the relative position of the electron beam 2 and the table 7 is formed of the metallic member and the many holes 8a having a prescribed shape are disposed on the surface thereof. The electron beam 2 is focused by an objective lens 3 and is polarized; thereafter, the electron beam scans on the marker 8 along loci 10. An electron sensor 9 detects the change in the radiation quantity of the reflected secondary electrons and a position correction processing part 20a counts the number of the holes 8a during this time. The correction signal for the positional deviation of the beam 2 and the table 7 is then outputted to a table control section 21 by which the table position is corrected. Since the correction is made by the measurement of the number of the holes, the accuracy of the table position correction is improved and the life of the marker 8 is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron beam control device suitable for use in various devices that utilize electron beams, such as electron beam welding machines.

[Prior Art] Fig. 5 is a schematic diagram showing the configuration of an electron beam control device in a conventional electron beam welding machine disclosed in, for example, Japanese Patent Application Laid-open No. 50-8697. A generating section, 2 is an electron beam, 3 is an objective lens (focusing means), 4 is a deflection lens (deflection means), 5 is a workpiece, 6 is a pallet on which the workpiece 5 is placed, 7 is a pallet 6 The table is fixed, and the electron beam 2 emitted from the electron beam generator 1 is focused by an objective lens 3.
It is deflected by a deflection lens 4. Further, 19 is a reflection electron sensor, 20 is a position correction processing section, 21 is a table control section, and 22 is a marker provided on the table 7 to detect the positional relationship between the table 7 and the electron beam 2.

FIG. 6(a) is a plan view of the marker 22, and in FIG. 6(a), the marker 23 indicated by the dotted line is different from the marker 22 indicated by the solid line due to the position shift of the table 7. indicates a misaligned state. The marker 22 has a cross-shaped groove 27 formed on the surface of a square platform member. Further, FIG. 6(b) is a cross-sectional view taken along the - line in FIG. 6(a), and as shown in this figure, the marker 22 has four peaks 28 and a cross-shaped groove 27. It is made up of. A trajectory 24 indicated by a thick dashed line is the trajectory of the electron beam 2, and indicates a state in which the marker 22 is irradiated. When the electron beam 2 moves along the trajectory 24,
The electron beam 2 is reflected by the peaks 28 and grooves 27 of the marker 22, and is detected by a reflection electron sensor 19 shown in FIG.

FIG. 7 is a cross-sectional view showing how the electron beam 2 is reflected by the marker 22. As shown in this figure, the electron beam 2-3, for example, irradiated onto the peak 28 is reflected by the peak 28, and the electron beam 2-4, and is detected by the reflection electron sensor 19. Further, for example, the electron beam 2-1 is reflected by the groove 27 and becomes an electron beam 2-2, but it does not hit the reflected electron sensor 19 and is therefore not detected.

The output waveform of the reflection electron sensor 19 when the electron beam 2 moves along the trajectory 24 shown in FIG. 6(a) is shown in FIG. 8(a).
) and (b). The electron beam hits point 2 in Figure 6(a).
When starting from point 4a and moving counterclockwise as shown by arrow B, boundaries 24b, 24c, 2 between peak 28 and groove 27
4d, 24f, 24g.

At 24h and 24i, the output signal changes and becomes the waveform shown in FIG. 8(a). In this waveform diagram, the high level corresponds to the peak 28 of the marker 22, and the low level corresponds to the groove 27 of the marker 22.

In FIG. 6(a), as shown by the dotted line, the marker 22
is shifted to the position of the marker 23, the peak 28
Each boundary between the groove 27 and the groove 27 is a boundary 26b.

Move to positions 26c, 26d, 26e, 26f, 26g, 26h and 26i. As a result, the detection output of the reflected electron sensor 19 has a waveform shown in FIG. 8(b). Comparing both the waveforms in FIG. 8(a) and FIG. 8(b), the waveform in FIG. 8(a) has a constant period, while the waveform in FIG.
The period of the waveform shown in Figure (b) is constantly changing. The position correction processing unit 20 outputs a control signal based on this periodic variation,
The table 7 is moved via the table control section 21, and the detected waveform of the backscattered electron sensor 19 is controlled to have a constant cycle as shown in FIG. 8(a), thereby correcting the positional deviation of the table 7.

[Problems to be Solved by the Invention] Since the conventional electron beam control device is configured as described above, in order to correct the position of the table 7, the method shown in FIG.
Since it is necessary to measure the time between the pulses obtained as shown in a) and (b) in the position correction processing section 20, the configuration of the position correction processing section 20 becomes complicated, and it is not possible to perform highly accurate correction. In order to do this, the electron beam 2 must be moved about 10 to 12 times along the trajectory 24 on the marker 22, which increases the irradiation time of the electron beam 2 on the marker 22 and causes deformation of the marker 22 due to heat generation. However, there have been problems such as inaccurate position correction and a shortened lifespan of the marker 22.

This invention was made in order to solve the above-mentioned problems, and when correcting the position of the table, the configuration of the 1-position correction processing section is simple, and moreover, it is possible to perform highly accurate position correction with a short electron beam irradiation time. The purpose of this study is to obtain an electron beam control device that can

[Means for Solving the Problems] An electron beam control device according to the present invention includes forming a marker as a metal member having a plurality of holes of a predetermined shape at appropriate positions on the surface, and a position correction processing unit. However, the number of holes in the marker scanned by the electron beam is counted based on changes in the output from the electronic sensor, and the relative displacement between the marker and the electron beam is detected based on the counted value.

[Function] In the electron beam control device according to the present invention, an electron beam is irradiated from the electron beam generating means to the marker and scans the marker. When a marker, which is a metal member, is irradiated with an electron beam, secondary electrons are emitted from the marker. When the electron beam passes through the hole in the marker, the amount of secondary electron radiation decreases significantly, and the electronic sensor detects this decrease in the amount of secondary electron radiation, causing the electron beam to pass through the hole in the marker. Scanning can be detected. In this way, by counting the number of holes in the marker scanned by the electron beam, the relative positional deviation between the marker and the electron beam can be detected from the counted value and the scanning direction. The table is driven by the table control unit based on the detection result of the deviation,
Position correction is performed.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
The figure is a schematic diagram showing the configuration of an electron beam control device according to an embodiment of the present invention. In the figure, 1 is an electron beam generator, 2 is an electron beam emitted from the electron beam generator 1, and 3 is an electron beam. An objective lens (focusing means) for focusing the beam 2, 4 a deflection lens (deflection means) for deflecting the focused electron beam 2, 5 a workpiece, 6 a pallet on which the workpiece 5 is placed, 7 is a table to which a pallet 6 is fixed; this table 7 is disposed on the surface where the electron beam 2 reaches, and is movable within a predetermined range.

A marker 8 is provided at a location on the table 7 where the electron beam 2 reaches, and is used to detect the relative positional relationship between the table 7 (marker 8) and the electron beam 2.
As shown in Figures 2 and 3, six eight
A is formed as a machined metal member with multiple holes at appropriate positions on the surface. Further, as shown in FIG. 2, the holes 8a are arranged at appropriate intervals in the X and Y directions, and the number of holes 8a along the It is formed by changing.

Further, reference numeral 9 denotes an electronic sensor 20A that is disposed between the deflection lens 4 and the marker 8 and detects emitted electrons from the marker 8.
is a position where a position correction signal is generated by counting the number of holes 8a of the marker 8 scanned by the electron beam 2 based on changes in the output from the electronic sensor 9, and detecting a relative positional deviation between the marker 8 and the electron beam 2. A correction processing section 21 is a position correction processing section 20
This is a table control unit that drives the table 7 based on the shift (position correction signal) detected by A to eliminate the shift.

Note that the electron beam generator 1 is configured so that the electron beam 2 is connected to the marker 8.
It is positioned so that it is irradiated.

Further, the electron beam generating section 1. Objective lens 3. The deflection lens 4 and the electronic sensor 9 are housed in a vacuum container (not shown).

Next, the operation of the apparatus of this embodiment will be explained.

The electron beam 2 emitted from the electron beam generator 1 is focused by the objective lens 3 and deflected by the deflection lens 4, and then moves in the direction of arrow X along the trajectory 10 on the marker 8 as shown in FIG. scan.

Generally, when an object is irradiated with electrons, secondary electrons are emitted from the surface of the object. The present invention utilizes this.

Therefore, when the electron beam 2 is irradiated onto the metal member that is the marker 8, the secondary electrons are emitted upward, but when the electron beam 2 is irradiated into the hole 8a, the secondary electrons are emitted downward. Therefore, the electron beam 2 is directed to the hole 8a of the marker 8.
The amount of secondary electron radiation decreases significantly when passing through the area.

The amount of secondary electrons emitted from marker 8 is
It is detected by an electronic sensor 9 placed near the marker 8, and the electronic sensor 9 detects a decrease in the amount of secondary electron radiation, thereby confirming that the electron beam 2 has scanned the hole 8'a of the marker 8. Detected. For example, when the electron beam 2 scans along the trajectory 10 shown in FIG. 2, as shown in FIG. A waveform at only one location can be obtained.

Furthermore, when scanning is performed along the locus 11 shown in FIG. 2, as shown in FIG. 4(b), since the hole 8a is not passed through, a waveform without a detection output decrease portion is obtained. Furthermore, when scanning is performed along the locus 12 shown in FIG. 2, a waveform is obtained in which the detection output decreases at four locations corresponding to the four holes 8a, as shown in FIG. 4(c). . In addition, the fourth
In FIGS. (a) to (c), the high level portion corresponds to the metal member portion of the marker 8, and the low level portion corresponds to the hole 8a of the marker 8 in the detection output decreasing portion.

The position correction processing unit 20A counts the number of pulses, that is, the number of holes 8a corresponding to the portion where the detection output decreases, based on the waveform from the electronic sensor 9, and calculates the Y by scanning the electron beam 2 along the X direction. Detect relative position in direction. Similarly, as shown in the trajectory 13 shown in FIG.
By scanning in the Y direction, the relative position in the X direction is also detected.

Based on the relative position in the X and Y directions detected in this way, that is, the deviation (relative positional relationship) between the table 7 (marker 8) and the electron beam 2, the position correction processing unit 20A sends the table control unit 21 to perform position correction. A signal is output, and the table 7 is driven and controlled by the table controller 21 to correct the position so that there is no deviation, that is, so that the number of pulses of the detected waveform from the electronic sensor 9 becomes a predetermined number.

In this way, according to the device of this embodiment, unlike the 7 conventional devices,
Since the position of the table 7 can be corrected without moving the electron beam 2 by about 10 to 12 revolutions or measuring the time between pulses, the configuration of the position correction processing section 20A can be extremely simplified. Yes, and at least twice (X, Y
direction) by scanning the electron beam 2, the table 7
Since the relative position of the marker 8 is detected, highly accurate position correction can be performed with a short electron beam irradiation time, and the irradiation time of the electron beam 2 on the marker 8 is also shortened, reducing deformation of the marker 8 and extending its life. can be taken as a thing.

[Effects of the Invention] As described in 2, according to the present invention, a marker made of a metal member having a large number of holes is used, and the number of holes is counted from the change in the amount of secondary radiation, thereby making it possible to calculate the number of holes on the table. Since the configuration is configured to be able to detect the relative position, the configuration of the position correction processing section is greatly simplified, and the relative position of the table is detected by at least two electron beam scans, so the electron beam irradiation time is shortened. This allows for highly accurate position correction, and furthermore, the electron beam irradiation time for the marker is shortened.

This has the effect of reducing deformation of the marker and extending its life.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an electron beam control device according to an embodiment of the present invention, FIG. 2 is a plan view showing a marker of the above embodiment device, and FIG. 3 is a partially cutaway view of the above marker. 4(a) to 4(c) are waveform diagrams for explaining the operation of the above-mentioned embodiment apparatus, FIG. 5 is a schematic diagram showing the configuration of a conventional electron beam control device, and FIG. FIG. 6(a) is a plan view showing the marker of the conventional device, FIG. 6(b) is a sectional view taken along the line - in FIG. 6(a), and FIG. 7 is the marker of the electron beam in the conventional device. 8(a) and 8(b) are waveform diagrams for explaining the operation of the conventional device. In the figure, 1-electron beam generation section, 2-electron beam,
3-1 objective lens (focusing means), 4-deflection lens (deflection means), 7-table, 8...-marker, 8a-hole, 9
-Electronic sensor, 20A-...Position correction processing section, 21.
-Table control. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] an electron beam generating means for generating an electron beam; a focusing means for focusing the electron beam; a deflection means for deflecting the focused electron beam; and an electron beam disposed on a surface where the electron beam reaches and capable of moving within a predetermined range. A table, a marker provided on the table where the electron beam reaches, an electronic sensor that detects electrons from the marker, and a link between the marker and the electron beam based on the output from the electronic sensor. In the electron beam control device, the electron beam control device includes a position correction processing unit that detects a deviation in relative position, and a table control unit that drives the table to eliminate the deviation based on the deviation detected by the position correction processing unit. The marker is a metal member in which a large number of holes of a predetermined shape are drilled at appropriate positions on the surface, and the position correction processing unit detects the marker scanned by the electron beam based on the output change from the electronic sensor. An electron beam control device characterized in that the deviation in the relative position is detected by counting the number of holes.