JP2554129Y2 - Faraday cup device with beam finder - Google Patents

Description

[Detailed description of the invention]

[0001]

2. Description of the Related Art In a semiconductor device manufacturing process, an ion implanter for implanting ions with an ion beam to dope impurities is used. In the semiconductor technology field, medical and biotechnology fields, a sample is irradiated with an ion beam. An ion analyzer for analyzing the composition and physical properties of a sample is used. These ion implanters and ion analyzers are provided with a Faraday cup device for measuring the beam current and a beam finder for observing the spot shape of the ion beam, the position of the ion beam with respect to the beam line axis, and the like. I have. This idea is
The present invention relates to a Faraday cup device with a beam finder, in which a Faraday cup device and a beam finder are integrated.

[0002]

2. Description of the Related Art FIG. 3 is a structural explanatory view showing an example of an ion analyzer for explaining the prior art. As shown in FIG. 1, the ion analyzer conventionally includes a plurality of Faraday cup devices 51 and 52 and beam finders 53 and 54, respectively. In the example shown in FIG. 3, a first Faraday cup device 51 and a first Faraday cup device 51 adjacent to the first Faraday cup device 51 are provided in a vacuum duct tube provided on the exit side of an acceleration tube 56 for accelerating an ion beam extracted from the ion source 55. The beam finder 53 is adapted to be individually moved forward and backward in a state where airtightness in the tube is maintained through the access holes provided in the peripheral wall of the vacuum duct tube at the time of measurement. The beam current of the passed ion beam is measured using the first Faraday cup device 51, and the spot shape of the ion beam and its position with respect to the beam line axis are observed by the first beam finder 53.

[0003] As shown in the figure, a second Faraday tube is provided in a vacuum duct tube provided upstream of a target chamber 58 in which a sample support 57 on which a sample to be analyzed is placed is disposed. The cup device 52 and the second beam finder 54 adjacent to the cup device 52 are individually moved forward and backward each time the measurement is performed, so that the ion beam before entering the target chamber 58 can be obtained. The beam current is measured using the second Faraday cup device 52, and the spot shape of the ion beam and its position with respect to the beam line axis are observed by the second beam finder 54. In FIG. 3, 59 is a filter, 60
Denotes a quadrupole electromagnet lens.

Next, a description will be given of a configuration example of a conventional Faraday cup device indicated by reference numerals 51 and 52, respectively. FIG.
FIG. 5 is a front view of an example of a conventional Faraday cup device, and FIG. 5 is a sectional view taken along line BB of FIG.

In FIGS. 4 and 5, reference numeral 71 denotes a plate-shaped restrictor plate having a circular opening 71a for passing an ion beam, and 72 denotes a conductive restrictor plate opening.
Opening to prevent collision of ion beam passing through 71a
An annular secondary electron suppressing annular electrode 73 having an inner diameter equal to or greater than the diameter of 71a has conductivity, has a bottom protruding in the direction of travel of the ion beam, and has a front surface facing the restrictor 71 side. This is an open beam current detection collector.

The conventional Faraday cup device includes the limiting aperture plate 71, the beam current detection collector 73, and the secondary electrode suppressing annular electrode 72 disposed therebetween, and these are connected to the limiting aperture plate opening. The mounting plate 75 is secured by bolts and nuts via an insulator 74 for electrically insulating each of the central axes 71a from each other so that the central axes coincide with each other.
It is fixed to.

The Faraday cup device has a mounting plate 75 attached to a not-shown Faraday cup drive mechanism, which is provided on the peripheral wall of the vacuum duct tube inside the vacuum duct tube through which the ion beam passes by the Faraday cup drive mechanism. The tube is configured to be able to advance and retreat while maintaining the airtightness in the tube through the access hole.

In the Faraday cup apparatus configured as described above, the ion beam that has passed through the restrictor aperture 71a enters the beam current detection collector 73 and is captured. An electric signal corresponding to the amount of charge of the ion beam detected by the beam current detection collector 73 is transmitted to a beam using a beam ammeter or the like via a beam current lead-out line (not shown) connected to a collector terminal 73a of the collector 73. It is provided to a current measuring device (not shown). Thereby, the beam current is measured.

In this case, the emission of secondary electrons from the beam current detection collector 73 due to the incidence of the ion beam is suppressed by the secondary electron suppressing ring electrode 72 to which a negative potential is applied via the ring electrode terminal 72a. The error due to the secondary electron emission of the measured beam current is reduced.

Next, an example of the configuration of the conventional beam finder indicated by the reference numerals 53 and 54 will be described. FIG. 6 is a front view of an example of a conventional beam finder, and FIG.
FIG. 4 is a sectional view taken along line C of FIG. 6 and 7, reference numeral 81 denotes a plate-like slit plate provided with a plurality of linear slits for inputting an ion beam, and reference numeral 82 denotes light emission when the ion beam passing through the slit of the slit plate 81 enters. A plate-like mirror 83 made of quartz, which causes the above-mentioned phenomenon, is a mirror holder having a concave portion having a step.

A conventional beam finder is a mirror holder.
The protective plate 84 and the mirror 82 were overlapped and fitted in the concave portion of the 83 so that the protective plate 84 was on the lower side, and the slit plate 81 superimposed on the surface of the mirror 82 was attached and fixed to the mirror holder 83 using bolts. Things. The protection plate 84 and the mirror
The spring 82 is pressed against the slit plate 81 by a spring 85 arranged in a recess of the mirror holder 83.
In this beam finder, the mirror holder 83 is attached to a beam finder drive mechanism, a part of which is shown in the figure, and the beam finder drive mechanism places the ion beam in the vacuum duct pipe through which the ion beam passes, on the peripheral wall of the vacuum duct pipe. The tube is configured to be able to move forward and backward in a state where airtightness in the tube is maintained through the provided access hole.

In the beam finder configured as described above, when the ion beam passing through the slit of the slit plate 81 collides with the mirror 82, light emission occurs at that portion. By observing the state of light emission of the mirror 82 from a view port (not shown) provided on the peripheral wall of the vacuum duct tube, the spot shape of the ion beam and its position with respect to the beam line axis are observed.

[0013]

As described above, the conventional Faraday cup apparatus and the conventional beam finder are configured to be individually provided in an ion analyzer and an ion implanter using an ion beam. . For this reason, in the conventional Faraday cup apparatus and beam finder, the beam current is measured in parallel with the observation of the spot shape of the ion beam by the beam finder in the ion analyzer and ion implanter equipped with these. Cannot be performed at the same time,
There is a disadvantage that it takes time to adjust the ion beam.

In addition, since it is necessary to separately provide a drive mechanism for moving the Faraday cup device and the beam finder into and out of the vacuum duct tube through which the ion beam passes at the time of measurement, it is necessary to separately provide a drive mechanism. There is also a disadvantage that the manufacturing cost of the ion implantation apparatus is increased and the structure is complicated.

The present invention has been made in order to solve the above-mentioned drawbacks. By integrating the Faraday cup apparatus and the beam finder, observation of the spot shape of the ion beam and the like, and the beam current Measurement can be performed in parallel instead of individually, and ion beam adjustment work in ion implantation equipment using ion beams, ion analyzers, etc. can be performed in a short time,
The beam finder can reduce the cost and simplify the structure of the ion implanter and the ion analyzer by eliminating the need to separately provide a drive mechanism for the Faraday cup device and a drive mechanism for the beam finder. The purpose of the present invention is to provide a Faraday cup device.

[0016]

In order to achieve the above object, a Faraday cup apparatus with a beam finder according to the present invention detects an electric charge of an ion beam by a beam current detecting collector and outputs an electric signal of the ion beam to an external beam. A Faraday cup with a beam finder that integrates a Faraday cup device for measuring the beam current given to a current measuring device and a beam finder for observing the ion beam spot shape, the position of the ion beam with respect to the beam line axis, etc. An apparatus, wherein the restricting aperture plate having an opening for passing the ion beam, at a position separated by a predetermined distance on the ion beam traveling direction side of the restricting aperture plate, the surface of the restricting aperture plate side is the said The ion beam is arranged so as to be inclined with respect to the opening forming surface of the restrictor, A mirror made of a material that emits light by being incident thereon and having a conductive film formed on the surface thereof; and a mirror holding the mirror and having an observation hole communicating with a surface of the mirror on the side of the restrictor plate. A holder, a beam current detection collector having conductivity and a beam current lead-out line connected thereto and disposed in close contact with a surface of the mirror on the side opposite to the restricting restrictor plate, and an opening of the restrictor restrictor plate; Has an inner diameter equal to or greater than the diameter of the ring and has conductivity, and has the same central axis as the center axis of the opening of the limiting aperture plate at a position between the limiting aperture plate and the mirror. A secondary-electrode suppressing annular electrode, and a mesh-shaped and electrically conductive secondary-electrode suppressing mesh plate disposed at the observation hole of the mirror holder. Was And it is characterized in and.

[0017]

When the ion beam that has passed through the aperture of the restrictor is incident on the surface of the mirror on the restrictor side, light is emitted at this part of the mirror. The state of this light emission is observed from outside through an observation hole provided in the mirror holder.

On the other hand, a conductive film is formed on the surface of the mirror, and the beam current detection collector is disposed in close contact with the surface of the mirror opposite to the surface on the side of the restrictor. The charge of the ion beam incident on the mirror is guided to the beam current detection collector. An electric signal corresponding to the charge amount of the ion beam detected by the beam current detection collector is supplied to an external beam current measuring device via a beam current derivation line. Thereby, observation of the spot shape of the ion beam and the like and measurement of the beam current can be performed in parallel.

Also, a secondary electron suppressing annular electrode provided at a position between the restricting aperture plate and the mirror, and a secondary electron suppressing annular electrode provided at an observation hole of the mirror holder. With the mesh plate, the emission of secondary electrons from the mirror due to the incidence of the ion beam is suppressed, and the error due to the secondary electron emission of the beam current measurement value can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a front view of a Faraday cup device with a beam finder according to an embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along line A.

In FIGS. 1 and 2, reference numeral 1 denotes a limiting aperture plate made of an insulating material and having a circular opening 1a for passing an ion beam. This is a mounting case in which a part and a rear surface are opened. Inside the mounting case 2, a cylindrical mirror holder 4 made of an insulator is placed on an insulator 3a disposed on the lower surface.
Are arranged in an upright posture, and the mirror holder 4
In this embodiment, the mirror 5 is made of quartz having a substantially circular shape in a plan view and a conductive film made of platinum formed on the surface. The mirror 5 is made to form an angle of 45 degrees between the limiting aperture plate 1 and the lower surface of the mounting case 2. It is attached so as to face the opening 1a of the plate 1.

As shown in the figure, the mirror holder 4 has an observation hole 4a communicating with the surface of the mirror 5 on the side of the restrictor 1 and is restricted by bolts via insulators 3a, 3b and 3c. It is adapted to be fixed to the squeezing plate 1.

The beam current detecting collector 6 is disposed in close contact with the surface of the mirror 5 opposite to the surface on the side of the restricting plate 1, and is fixed to the restricting plate 1 together with the mirror holder 4. Thus, in this embodiment, it is formed using oxygen-free copper. A beam current deriving line 7 for supplying an electric signal to a beam current measuring device (not shown) is connected to the beam current detection collector 6.

On the other hand, in order to prevent the ion beam passing through the restriction aperture plate opening 1a from colliding, an annular secondary electron suppressing annular electrode 8 having the same inner diameter as the diameter of the aperture 1a is provided with the restriction aperture plate 1 and The central axis of the restriction aperture plate opening 1a and the central axis thereof are arranged at a position between the mirror 5 and the restricting aperture 1a. In this embodiment, the secondary electrode suppressing annular electrode 8 is formed using copper.

Further, on the periphery of the upper end of the mirror holding member 4,
A conductive and reticulated mesh 2 is provided so that the surface of the mirror 5 on the side of the restrictor 1 can be observed from outside through the observation hole 4a.
A mesh plate 9 for suppressing secondary electrons is attached. In addition, the Faraday cup device with a beam finder configured as described above is attached to the distal end of a moving shaft S that forms a part of a drive mechanism and is internally cooled with water, as shown in FIG. The driving mechanism is configured to be movable in a vacuum duct tube through which an ion beam passes through an access hole provided in a peripheral wall of the vacuum duct tube in a state where the airtightness of the tube is maintained.

The operation of the Faraday cup device with a beam finder having the above configuration will be described below. When the ion beam that has passed through the opening 1a of the limiting aperture plate 1 is incident on the surface of the mirror 5 on the limiting aperture plate 1 side, light emission occurs at the beam incident portion of the mirror 5. By observing the state of this light emission from an observation window provided on the upper peripheral wall of the vacuum duct tube through an observation hole 4a provided in the mirror holder 4, the spot shape of the ion beam and its position with respect to the beam line axis are observed. be able to.

On the other hand, a conductive film is formed on the surface of the mirror 5, and the beam current detecting collector 6 is disposed in close contact with the surface of the mirror 5 opposite to the surface on the side of the restrictor 1. The charge of the ion beam incident on the mirror 5 is guided to the beam current detection collector 6. As a result, an electric signal corresponding to the charge amount of the ion beam detected by the beam current detection collector 6 is given to an external beam current measurement device via the beam current derivation line 7, and thereby the beam current is reduced. Can be measured.

In this case, the annular electrode 8 for suppressing secondary electrons and the mesh plate 9 are in a state where a negative bias is given by capturing the secondary electrons hit from the mirror in the initial stage. Accordingly, the secondary electron suppression annular electrode 8 and the secondary electron suppression mesh plate 9 suppress the emission of secondary electrons from the mirror 5 due to the incidence of the ion beam, and the error of the measured beam current due to the secondary electron emission. Can be reduced.

In this manner, the observation of the spot shape of the ion beam and the measurement of the beam current can be performed simultaneously in parallel, instead of individually as in the conventional case. A configuration may be adopted in which a negative potential is applied in advance to the secondary electron suppressing annular electrode 8 and the secondary electron suppressing mesh plate 9 from a power supply.

[0030]

As described above, according to the Faraday cup device with the beam finder according to the present invention, the charge amount of the ion beam is detected by the beam current detection collector, and the electric signal is given to the external beam current measurement device. Since the Faraday cup device for measuring the beam current and the beam finder for observing the spot shape of the ion beam, the position of the ion beam with respect to the beam line axis, and the like are integrated, the ion beam Observation of the spot shape, etc. and measurement of the beam current can be performed simultaneously and in parallel, instead of individually as in the past, so that the ion beam adjustment work in the ion implanter or ion analyzer can be performed in a shorter time than in the past. Can be done with In addition, by applying the Faraday cup device with a beam finder according to the present invention to an ion implantation device and an ion analyzer using an ion beam, a drive mechanism for the Faraday cup device and a drive mechanism for the beam finder are separately provided. This eliminates the necessity, and can reduce the cost and simplify the structure of the ion implantation apparatus and the ion analysis apparatus.

[Brief description of the drawings]

FIG. 1 is a front view of a Faraday cup device with a beam finder according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a configuration explanatory view showing an example of an ion analyzer for explaining a conventional technique.

FIG. 4 is a front view of an example of a conventional Faraday cup device.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a front view of an example of a conventional beam finder.

FIG. 7 is a sectional view taken along line CC of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Restricted aperture plate 1a ... Restricted aperture plate opening 2 ... Mounting case 3a, 3b, 3c ... Insulator 4 ... Mirror holder 4a
... Observation hole 5 ... Mirror 6 ... Beam current detection collector
7 ... Beam current derivation line 8 ... Annular electrode for secondary electron suppression
9 ... mesh plate for suppressing secondary electrons

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01J 37/317 H01J 37/317 C

Claims (1)

(57) [Scope of request for utility model registration] 1. A Faraday cup device for detecting a charge amount of an ion beam by a beam current detection collector and applying an electric signal to an external beam current measurement device to measure a beam current; A Faraday cup device with a beam finder integrated with a beam finder for observing a position of an ion beam with respect to a beam line axis, etc., wherein a limiting aperture plate having an opening through which the ion beam passes, and the limiting aperture At a position separated by a predetermined interval on the side of the plate in the direction of traveling of the ion beam, the surface on the side of the restricting restrictor is disposed so as to be inclined with respect to the opening forming surface of the restrictor, and the ion beam is incident. A mirror made of a material that emits light by the method and having a conductive film formed on the surface thereof; And a mirror holding body provided with an observation hole communicating with the surface of the mirror on the side of the restricting restrictor plate, and a conductive and beam current lead-out line connected to the mirror, on the opposite restricting restrictor plate side of the mirror. A beam current detection collector disposed in a state of being in close contact with the surface of the limiting aperture plate, having an inner diameter equal to or greater than the diameter of the opening of the limiting aperture plate, forming an annular shape, and having conductivity; A secondary electrode suppressing annular electrode disposed at a position between the restricting restrictor and the mirror so that the central axis of the restricting restrictor opening is substantially the same as the central axis thereof; A Faraday cup device with a beam finder, further comprising: a secondary electron suppressing mesh plate disposed at an observation hole of the mirror holder.