JP4235048B2 - Electron source device and method of adjusting electron source device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron source device that irradiates an irradiated material with an electron beam and an electron source device adjustment method.
[0002]
[Prior art]
The electrons emitted from the heated filament are accelerated and drawn out, rotated by about 180 degrees by a magnetic field, and turned into an electron beam spot by a lens action while irradiating the material to be dissolved in the crucible within the predetermined region. Are scanned in the X direction and the Y direction, and a predetermined region of the material to be dissolved is heated almost uniformly with the energy of the electron beam to be melted and evaporated, and then deposited on a substrate disposed on the opposite surface. There is a source device.
[0003]
Conventionally, an electron source device needs to be rotated about 180 degrees to guide an electron beam emitted from a filament and accelerated into the crucible. A magnetic field is used to rotate the electron beam and an electron beam spot is covered in the crucible. In order to perform a planar scan within a predetermined area in the center of the melted material surface, an X scan coil and a Y scan coil are arranged and deflected in the course of the electron beam spot path, and the predetermined area is scanned in a plane and irradiated. The material was heated uniformly.
[0004]
[Problems to be solved by the invention]
However, the above-described X scan coil and Y scan coil are magnetized by a magnetic field for rotating the electron beam from 180 degrees to 180 degrees, and when a scan waveform current for scanning is supplied, as shown in FIG. A saturation phenomenon occurs in the circuit, and in the saturated region, the electron beam spot stops scanning within a predetermined region of the irradiated material in the crucible and irradiates the same place. It evaporates faster than the part of the film, and uneven deposition occurs on the substrate placed opposite to it. Further, a hole is formed in the irradiated material, and if the hole is opened, the irradiated material cannot be used. Therefore, there is a problem that the utilization efficiency of the expensive irradiated material is lowered.
[0005]
In order to solve these problems, the present invention rotates the electron beam by 180 degrees or more by a magnetic field and irradiates the surface of the material to be irradiated in the crucible from a substantially vertical direction while performing a plane scan in a predetermined area with a scan coil. Then, a current that just cancels the magnetic flux interlinked with the iron core of the scan coil by the permanent magnet is caused to flow through the scan coil, and the electron beam spot is uniformly scanned over the predetermined area of the material to be irradiated in the crucible. The object is to achieve uniform heating of the irradiated material and to improve the utilization efficiency of the irradiated material by uniformly melting the irradiated material.
[0006]
[Means for Solving the Problems]
Means for solving the problem will be described with reference to FIG.
In FIG. 1, a permanent magnet 1 generates a magnetic field for irradiating the center of an irradiated material surface in a crucible 6 vertically by rotating an electron beam 12 emitted from a filament 11 and accelerated by 180 degrees or more. To do.
[0007]
The scan coil 4 performs a plane scan (X, Y scan) on a predetermined region of an electron beam spot that irradiates the surface of the material in the crucible 6 vertically and substantially at the center.
[0008]
The iron core 5 is a magnetic path that guides the magnetic flux generated by the scan coil 4. Here, the iron core 5 is an iron core through which the magnetic flux generated by the permanent magnet 1 passes.
The crucible 6 is a crucible for putting a material to be irradiated, irradiating an electron beam spot, scanning a predetermined area in a plane, and heating and evaporating it uniformly.
[0009]
The filament 11 is a filament that emits an electron beam 12 by being energized and heated.
Next, the configuration and operation will be described.
[0010]
In a state where the electron beam 12 emitted from the heated filament 11 and accelerated is rotated by 180 degrees or more by the magnetic field of the permanent magnet 1 to irradiate the irradiated material in the crucible 6 almost vertically and at the center. Then, a scanning current is supplied to the material to be irradiated in the crucible 6 so that the material to be irradiated is substantially perpendicularly scanned in a predetermined plane and heated uniformly, evaporated and deposited on a substrate disposed on the opposite surface. At this time, a predetermined value is applied to the scan coil 4 (or a coil (not shown) separately wound around the core rod 5) so that the magnetic flux generated by the permanent magnet 1 is generated in a direction opposite to the direction passing through the iron core 5 in the scan coil 4. In a state in which a current is applied, a scanning current is supplied to the scanning coil 4 to eliminate saturation, and an electron beam spot that performs planar scanning within a predetermined region of the irradiated material in the crucible 6 almost stops and heating unevenness occurs. It does not occur.
[0011]
In addition, the current supplied to the scan coil 4 (or another coil wound around the iron core 5) is set to a predetermined current corresponding to the acceleration voltage measured in advance, and the predetermined area is substantially perpendicular to the irradiated sample surface in the crucible 6. It scans and heats uniformly.
[0012]
Therefore, when the scanning coil 4 performs plane scanning within a predetermined region while rotating the electron beam 12 by 180 degrees or more by a magnetic field and irradiating the surface of the material to be irradiated in the crucible 6 from a substantially vertical direction, the scanning coil by the permanent magnet 1 is used. A current that exactly cancels the magnetic flux interlinking with the iron core 5 of 4 is applied to the scan coil 4 (or a coil wound around the iron core 5), and the electron beam spot is uniformly scanned in a predetermined area of the irradiated material in the crucible. By doing so, it is possible to achieve uniform heating of the irradiated material by the electron beam spot and to uniformly melt the irradiated material to improve the utilization efficiency of the irradiated material.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments and operations of the present invention will be sequentially described in detail with reference to FIGS.
[0014]
FIG. 1 is an explanatory diagram of the present invention.
1A shows a top view, and FIG. 1B shows a front view.
In FIG. 1, a permanent magnet 1 rotates an electron beam emitted from a filament 11 and accelerated by 180 degrees to generate a magnetic field for irradiating the surface of a material to be irradiated in a crucible 6 vertically and substantially at the center. Is.
[0015]
The shunt rod 2 is a magnetic path for guiding the magnetic field generated by the permanent magnet 1 and is a rod-shaped one made of soft iron.
The DEF coil 3 corrects variations in the strength of the magnetic field of the permanent magnet 1 and is a coil wound coaxially and close to the permanent magnet 1.
[0016]
The scan coil (X, Y) 4 generates a scanning magnetic field, scans the electron beam spot that irradiates the center substantially perpendicular to the surface of the material to be irradiated in the crucible 6 within a predetermined area, and scans the area within the area. This is for heating the irradiation material uniformly.
[0017]
The iron core 5 is a magnetic path for guiding a magnetic field generated by passing a current through the scan coil 4. Here, the iron core 5 is a magnetic path through which the magnetic field generated by the permanent magnet 1 passes. A current that generates a magnetic flux that just cancels the magnetic flux passing through the iron core 5 by the permanent magnet 1 is supplied to the scan coil 4 itself wound around the iron core or another coil wound around the iron core 5.
[0018]
The crucible 6 is used for putting a material to be irradiated, scanning a predetermined area almost vertically with an electron beam spot, heating and evaporating the predetermined area uniformly, and depositing it on a substrate disposed on the opposite surface. Is.
[0019]
The filament 11 emits an electron beam 12, and is formed, for example, by forming a tungsten wire into a hairpin shape, and emits an electron beam by heating with an electric current.
[0020]
The electron beam 12 applies electrons emitted from the heated filament 11 by applying a bias voltage and an accelerating voltage (for example, 10 KV) to the grid electrode provided opposite to each other and the anode electrode provided oppositely. This is for emitting the electron beam 12 having a predetermined current and voltage.
[0021]
A shows an example of the position (position of the upper surface of the electron gun) when the upper surface of the electron gun is higher than the crucible 6 (other device). In the case of A, radiant heat from the crucible 6 is directly incident on the upper surface of the electron gun and heated, or further, the irradiated material in the crucible 6 is dissolved and evaporated to adhere to the upper surface of the electron gun and become dirty. As a result, the electron beam 12 (having a potential of 10 KV) is discharged and becomes unstable.
[0022]
B shows an example of the position (position of the upper surface of the electron gun) when the upper surface of the electron gun of the present invention is the same height or lower than the crucible 6. In the case of B, the radiant heat from the crucible 6 does not directly enter the upper surface of the electron gun, so it is not heated, and the irradiated material in the crucible 6 melts and evaporates and does not adhere to the upper surface of the electron gun. The electron beam 12 (having a potential of 10 KV) is beautiful and can be stabilized without being discharged. As shown in FIG. 1B, in order to make the surface the same as or lower than the surface of the crucible 6, the electron beam emitted from the filament 11 is accelerated, the center O of the magnetic field generated by the permanent magnet 1 is This can be realized by moving upward in (b).
[0023]
FIG. 2 is an explanatory diagram of the present invention. This is because the iron core 5 of the scan coil (X) 4 is arranged in the magnetic field generated by the permanent magnet 1 in FIG. 1, and magnetization Xm by the permanent magnet 1 is generated in the iron core 5. A current is passed through the scan coil (X) 4 (or a coil wound around the iron core 5 not shown) so as to cancel the generated magnetization Xm, and as a result, the magnetization by the permanent magnet 1 is corrected to zero. Thereby, when a scanning current having positive and negative symmetry is supplied to the iron core 5, the electron beam spot is uniformly scanned in a predetermined rectangular area around the center of the irradiated material in the crucible 6 and heated uniformly. It becomes possible.
[0024]
FIG. 3 shows an example of the cancel current setting procedure of the present invention.
In FIG. 3, S1 calculates | requires the electric current Xc with respect to a shunt rod cross-sectional area. This is influenced by the magnetic field generated by the permanent magnet 1 shown in FIG. 1 (interlink of the magnetic field). Here, a plurality of shunt rods 2 in which the cross-sectional area of the shunt rod 2 is changed and the illustrated positions are shown. Necessary for canceling the magnetic field (magnetic flux) from the permanent magnet 1 linked to the iron core 5 just in order (attaching a magnetometer to the iron core 5 to cancel the magnetic flux just zero) The current flowing through the scan coil (X) 4 is experimentally measured, and the curve of the current Xc with respect to the shunt rod cross-sectional area S in FIG. )
[0025]
S2 calculates | requires the acceleration voltage ACC with respect to shunt rod cross-sectional area. This is influenced by the magnetic field generated by the permanent magnet 1 shown in FIG. 1 (interlink of the magnetic field). Here, a plurality of shunt rods 2 in which the cross-sectional area of the shunt rod 2 is changed and the illustrated positions are shown. Necessary for canceling the magnetic field (magnetic flux) from the permanent magnet 1 linked to the iron core 5 just in order (attaching a magnetometer to the iron core 5 to cancel the magnetic flux just zero) In a state in which the current is constantly adjusted to flow through the scan coil (X) 4, the relationship with the acceleration voltage ACC of the electron beam when the cross-sectional area of the shunt rod 2 is changed is measured, and these measured values The curve of the acceleration voltage ACC with respect to the shunt rod cross-sectional area S in FIG.
[0026]
S3 calculates | requires shunt rod cross-sectional area S1 with respect to ACC K1 (KV), and also calculates | requires X1 from S1. This is because the current X1 flowing through the scan coil (X) 4 in FIG. 1 is determined and set from the experimental results of S1 and S2.
The cross-sectional area S1 of the shunt rod with respect to the acceleration voltage K1 of the electron beam 11 is obtained from the curve of FIG.
[0027]
The current X1 flowing through the scan coil (X) 4 with respect to the obtained shunt rod cross-sectional area S1 is obtained from the line segment of FIG.
S4 incorporates the scan coil (X, Y). This incorporates the assembly of scan coil (X, Y) 4 of FIG. 1 as shown.
[0028]
S5 is set so that the X1 current flows through the affected scan coil. This is affected by the magnetic field of the permanent magnet 1 of the scan coil current control circuit (not shown) after the scan coil (X, Y) 4 is incorporated as shown in FIG. Magnetic flux generated by the influence of the permanent magnet 1 on the scan coil (X) 4 by supplying the current X1 corresponding to the acceleration voltage of the current electron beam 11 obtained in S3 by adjusting the adjustment volume of (X) 4. Cancel.
[0029]
When the voltage for accelerating the electron beam 11 is determined in the configuration shown in FIG. 1, the current flowing through the scan coil (X) 4 corresponding to the acceleration voltage is determined using the curves (b) and (a) in FIG. In this case, the calculated current is adjusted to flow through the scan coil (X) 4 which is affected by the magnetic field generated by the permanent magnet 1, and then the scan current is supplied to the scan coil (X, Y) 4. Thus, it is possible to heat by scanning the range of the predetermined region uniformly around the center of the irradiated material in the crucible 6. As a result, the electron beam spot stops scanning due to magnetic saturation of the iron core 5 at any location in the predetermined scanning range on the surface of the material to be irradiated in the crucible 6, and heating is partially excessively caused. It is possible to create a vapor deposition film with less unevenness by performing uniform heating while eliminating the situation in which the efficiency of use of the irradiated material is reduced due to partial evaporation of the film.
[0030]
FIG. 4 is an explanatory diagram (cancellation current) of the present invention.
4A is a curve showing the relationship of the current Xc flowing through the scan coil with respect to the shunt rod cross-sectional area S. FIG. This is affected by the magnetic field generated by the permanent magnet 1 of FIG. 1 (interlinkage of the magnetic field), as described above in S1 of FIG. 3. Here, a plurality of cross-sectional areas of the shunt rod 2 are changed. The shunt rod 2 is created and arranged in the order shown in the figure, and the magnetic field (magnetic flux) from the permanent magnet 1 linked to the iron core 5 is canceled just (the magnetometer is attached to the iron core 5 and the magnetic flux is This is a curve (here, almost a straight line) created by plotting these measured values by experimentally measuring the currents that flow through the scan coil (X) 4 necessary to cancel (just canceling with zero). .
[0031]
FIG. 4B is a curve showing the relationship of the current Xc flowing through the scan coil with respect to the shunt rod cross-sectional area S. This is affected by the magnetic field generated by the permanent magnet 1 of FIG. 1 (interlinkage of the magnetic field), as described above in S2 of FIG. 3. Here, a plurality of cross-sectional areas of the shunt rod 2 are changed. The shunt rod 2 is created and arranged in the order shown in the figure, and the magnetic field (magnetic flux) from the permanent magnet 1 linked to the iron core 5 is canceled just (the magnetometer is attached to the iron core 5 and the magnetic flux is The acceleration voltage ACC of the electron beam when the cross-sectional area of the shunt rod 2 is changed in a state in which the current necessary for passing the current to the scan coil (X) 4 is always adjusted so These curves are prepared by plotting these measured values.
[0032]
FIG. 5 shows a waveform diagram of the present invention. This is because the current that cancels the magnetic field affected by the magnetic field generated by the permanent magnet 1 of FIG. 1 in S5 of FIG. 3 is applied to the scan coil (X) 4 (or the coil that is wound around the iron core 5 separately). ), A scanning current (a scanning current symmetric between positive and negative) is passed through the scan coil (X) 4 to scan the predetermined region uniformly around the center of the irradiated material in the crucible 6 and heat it. This is a schematic representation of the magnetic field (magnetic flux) generated by the iron core 5 when measured. Here, a cancel current (S5 in FIG. 3) is applied to the scan coil (X) 4 (or a coil wound separately) of the iron core 5 affected by the permanent magnet 1 so as to cancel the influence of the magnetic field generated by the permanent magnet 1. ) Is set and flowed, so that a scan current (positive and negative symmetric scan current) is always passed through the scan coil (X) 4 and the scan coil (Y) 4 that is not affected by the magnetic field generated by the permanent magnet 1. Thus, an electron beam spot can be scanned uniformly in a predetermined rectangular area around the center of the irradiated material in the crucible 6 and heated, and a portion of the irradiated material is excessively irradiated to melt quickly. It is possible to improve the utilization efficiency of the irradiated material without opening it, and to form a deposited film with little variation by heating uniformly.
[0033]
【The invention's effect】
As described above, according to the present invention, the electron beam 12 is rotated 180 degrees or more by a magnetic field to irradiate the surface of the material to be irradiated in the crucible 6 from a substantially vertical direction, and the scanning coil 4 performs planar scanning in a predetermined region. In doing so, a current that cancels the magnetic flux interlinked with the iron core 5 of the scan coil 4 by the permanent magnet 1 is passed through the scan coil 4 (or a coil wound around the iron core 5 separately) to cause the electron beam spot to pass through the crucible 6. Since a configuration in which a predetermined region of the irradiated material is uniformly scanned in a plane is adopted, uniform heating of the irradiated material by the electron beam spot is realized and the irradiated material is uniformly melted to improve the utilization efficiency of the irradiated material. It becomes possible to improve.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of the present invention.
FIG. 2 is an explanatory diagram of the present invention.
FIG. 3 is an example of a cancel current setting procedure according to the present invention.
FIG. 4 is an explanatory diagram (cancellation current) of the present invention.
FIG. 5 is a waveform diagram of the present invention.
FIG. 6 is a conventional waveform diagram.
[Explanation of symbols]
1: Permanent magnet 2: Shunt rod 3: DEF coil 4: Scan coil (X, Y)
5: Iron core 6: Crucible 11: Filament 12: Electron beam

Claims (3)

A magnet that rotates an electron beam emitted from an electron source and accelerated by a magnetic field by 180 degrees or more to irradiate an irradiated material from a substantially vertical direction;
A deflection coil for planarly scanning a position where the electron beam spot is irradiated from a substantially vertical direction of the irradiated material by supplying a scanning current within a predetermined region;
A current that generates a magnetic flux that cancels the magnetic flux generated by the magnet and interlinked with the magnetic core of the deflection coil is supplied to a coil that is superimposed on the deflection coil itself or that is separately wound around the magnetic core of the deflection coil. An electron source device comprising a coil current control circuit. Assuming that a current is generated that generates a magnetic flux that just cancels the magnetic flux generated by the magnet and interlinks with the magnetic core of the deflection coil, the current is generated by the magnet in association with an acceleration voltage for accelerating the electron beam. 2. The electron source device according to claim 1, wherein a predetermined current that has been measured and stored in advance by an experiment is supplied to generate a magnetic flux that just cancels the magnetic flux interlinking with the magnetic core of the deflection coil . A magnet that rotates an electron beam emitted from an electron source and accelerated by a magnetic field by 180 degrees or more to irradiate an irradiated material from a substantially vertical direction;
A deflection coil for planarly scanning a position where the electron beam spot radiates from a substantially vertical direction of the irradiated material by supplying a scanning current within a predetermined region;
A coil that supplies a current that generates a magnetic flux that is superimposed on the deflection coil itself or that is wound around a magnetic core of the deflection coil and that just cancels the magnetic flux generated by the magnet and linked to the magnetic core of the deflection coil. An electron source device with a current control circuit,
An adjustment method for an electron source device , characterized in that the coil current control circuit adjusts so as to supply a current that generates a magnetic flux that is generated by the magnet and just cancels the magnetic flux interlinked with the magnetic core of the deflection coil. .

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