JP4050848B2 - Electron beam evaporator - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to an electron beam evaporation apparatus configured to bend an electron beam from an electron gun in a curved shape and irradiate an evaporation substance in a crucible.
[0002]
[Prior art]
A vacuum vapor deposition apparatus, an ion plating apparatus, and the like are provided with an electron beam evaporation apparatus. For example, a material (evaporation substance) to be vapor deposited on a substrate is accommodated in a crucible and provided on the side or the lower side of the crucible. The electron beam from the electron gun is deflected in a curved line by a magnetic field and guided to the evaporated material in the crucible, and the evaporated material is heated and evaporated.
[0003]
FIG. 1 shows an outline of such an electron beam evaporation apparatus, and FIG. 2 is a sectional view taken along line AA of FIG.
[0004]
In the figure, 1A and 1B are magnetic pole plates arranged in parallel with the permanent magnet 2 in between, and are excited by the permanent magnet 2 to the N pole and the S pole. A crucible 4 in which the evaporating substance 3 is accommodated is provided between the magnetic pole plates. An electron gun 5 is provided under the crucible. The electron gun comprises a filament 6, a grid 7 and an anode 8. 9 is a filament heating power source and 10 is an acceleration power source. Reference numeral 11 denotes a grid support plate. Reference numeral 12 denotes a scanning electromagnetic coil body in which an X-direction scanning deflection coil and a Y-direction scanning deflection coil are wound around an annular iron core, which is disposed on the electron beam path from the electron gun 5. The scanning electromagnetic coil body is supported by, for example, a non-magnetic holder (not shown) attached near the crucible 4 between the magnetic poles 1A and 1B. Reference numeral 13 denotes a scanning power source for supplying a scanning current to the scanning electromagnetic coil body.
[0005]
In such an apparatus, the electron beam generated from the filament 6 of the electron gun 5 is accelerated by the anode 8 and passes through the grid 7 and the beam passage holes 7H and 8H of the anode 8. At this time, the opening angle of the electron beam is determined by the beam passage holes 7H and 8H of the grid 7 and the anode 8. Then, the electrons exiting the beam passage hole 8H of the anode 8 are irradiated to the evaporating substance 3 which is bent around 270 ° and accommodated in the crucible 4 so as to draw a Ramor circle by the magnetic field generated by the magnetic poles 1A and 1B. At this time, since the electron beam from the electron gun 5 passes through the two-dimensional scanning magnetic field created by the scanning electromagnetic coil body 12, the electron beam scans the evaporation substance 3 in the two-dimensional direction. As a result, the evaporating substance 3 is heated by the electron beam to evaporate, and the evaporated particles adhere to, for example, each substrate (not shown) disposed above the crucible 4.
[0006]
[Problems to be solved by the invention]
In such an electron beam evaporation apparatus, there is a demand for the distribution of the evaporated particles in a plane perpendicular to the axis perpendicular to the surface of the evaporated substance to be close to a desired state above the crucible. For example, there is a demand for uniform deposition film thickness on a plurality of substrates (not shown) supported by a dome-shaped substrate support plate (not shown) provided above the crucible. In order to realize this demand, it is necessary to always keep the radiation angle of the evaporated particles evaporating from each position of the evaporating substance 3 toward the upper substrate group substantially constant at each position. At this time, the dome-shaped substrate support plate is rotated around an axis passing through the center thereof.
[0007]
For this purpose, it is necessary that the incidence of the electron beam at each position of the evaporating substance 3 is kept close to the vertical, and the amount of evaporation at each position of the evaporating substance 3 is made close to the same. Usually, in such an electron beam evaporation apparatus, the shape of a magnetic pole provided in a part of or separately from the magnetic pole plates 1A and 1B so that the cross-sectional shape of the electron beam incident on the evaporating substance is drawn circularly is drawn. I am devised. Therefore, if the incidence of the electron beam on the evaporating substance is close to the vertical, the cross-sectional shape of the electron beam irradiated on the evaporating substance is almost round, and the evaporation amount at each position of the evaporating substance is always nearly constant. However, when the incident angle of the electron beam with respect to the evaporating substance is deviated, the cross section of the electron beam on the evaporating substance is deviated from a round shape (for example, an ellipse or an ellipse), and the evaporation amount of the evaporating substance is not constant.
[0008]
By the way, in such an electron beam evaporation apparatus, evaporated particles adhere to the magnetic pole and the like, so these parts must be disassembled and cleaned from time to time. However, every time the parts are assembled and the apparatus is operated after cleaning, the incident angle of the electron beam to each position of the evaporating substance 3 is shifted based on the positional deviation of the parts such as the magnetic poles. That is, the reproducibility of the incident angle of the electron beam before the parts disassembly and after the parts assembly sandwiching the cleaning operation is poor. Therefore, it is necessary to repeat the precise adjustment of the mounting position of the magnetic poles and the like every time, and the working efficiency is extremely poor.
[0009]
When the acceleration voltage is changed, the incident angle of the electron beam to each position of the evaporating substance 3 is shifted.
[0010]
The present invention has been made to solve such problems, and an object of the present invention is to provide a novel electron beam evaporation apparatus.
[0011]
[Means for Solving the Problems]
The electron beam evaporation apparatus according to the present invention is provided with a crucible containing an electron gun and an evaporated substance between at least one pair of deflection magnetic poles, and the electron beam emitted from the electron gun is deflected by a magnetic field formed by the deflection magnetic poles. The evaporating material in the crucible is irradiated, and an electron beam evaporation system is provided in which a scanning deflector is provided on the electron beam path to scan the evaporating material with the electron beam. In the apparatus, acceleration of the electron beam is provided by providing an electromagnetic coil that can magnetically affect the magnetic field formed between the deflection magnetic poles and can form a new magnetic field in a direction parallel to the direction of the magnetic field. depending on the voltage value, the magnetic field strength of the electron beam angles a deflecting magnetic pole to a predetermined value that is incident on the evaporation material by the electromagnetic coil to control the magnetic field to be formed is formed There is characterized in that form as the control.
[0012]
Further, the electron beam evaporation apparatus of the present invention corrects the magnetic field intensity correction for correcting the deviation of the electron beam incident angle with respect to each acceleration voltage value different from the standard acceleration voltage value at which the angle of the electron beam incident on the evaporation substance becomes a predetermined value. A memory storing data corresponding to each acceleration voltage value is provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 3 shows one schematic example of the electron beam evaporation apparatus of the present invention. In the figure, the same reference numerals as those in FIGS. 1 and 2 denote the same components.
[0015]
The difference in configuration of the electron beam evaporation apparatus shown in FIG. 3 with respect to FIGS. 1 and 2 is as follows.
[0016]
In FIG. 3, a correction electromagnetic coil 20 is provided in the vicinity of the upper portion of the crucible 4 to form a magnetic field having a magnetic field line substantially parallel to the magnetic field lines generated by the magnetic poles 1 </ b> A and 1 </ b> B. Reference numeral 21 denotes an excitation power source for supplying an excitation current to the correction electromagnetic coil, which operates based on a command from a control device 22 such as an electronic computer. A memory 23 stores correction excitation current value data for acceleration voltage value data.
[0017]
Next, the operation of the apparatus having such a configuration will be described.
[0018]
First, as an initial state of the apparatus, at a standard acceleration voltage V ₀ , a magnetic pole provided partially or separately on the magnetic pole plates 1A and 1B so that a cross-sectional shape of an electron beam incident on the evaporated substance is drawn circularly at a standard acceleration voltage V ₀ . The shape of this is devised, and the incidence of the electron beam at each position of the evaporating substance 3 is kept close to the vertical.
[0019]
In addition, when the acceleration voltage is changed to a voltage value different from the standard value V ₀ in advance, the one corresponding to the deviation of the electron beam incident angle with respect to each voltage value is measured, and the magnetic field for correcting each deviation is measured. A correction value (excitation current value) is obtained in advance. Each acceleration voltage value data and magnetic field correction value data (excitation current value data) for the voltage value data are tabulated and stored in the memory 23. What corresponds to the deviation of the incident angle of the electron beam with respect to each acceleration voltage value can be measured as follows.
[0020]
The acceleration voltage value is set to a value different from the standard value V _0, and corresponds to the incident angle of the electron beam with respect to the acceleration voltage from the melting state of the evaporation substance in a specific region of the evaporation substance 3 in the crucible 4 at that time. Things can be estimated. In this case, the evaporating substance is not scanned by the electron beam.
[0021]
As the acceleration voltage increases, the deflection of the electron beam by the magnetic poles 1A and 1B becomes difficult to follow according to the difference from the standard value V _0, and the incident angle of the electron beam with respect to the evaporating material becomes smaller and enters slightly before the standard time. The cross-sectional shape on the evaporating material extends in a direction perpendicular to the magnetic field direction. On the other hand, when the acceleration voltage decreases, the electron beam is easily deflected by the magnetic poles 1A and 1B according to the difference from the standard value V ₀ , the incident angle of the electron beam with respect to the evaporating substance increases, and is irradiated to the rear side from the standard time. The cross-sectional shape on the evaporating material extends in a direction perpendicular to the magnetic field direction. For example, as shown in FIG. 4 (a), if the standard acceleration voltage is V _0, the electron beam cross section in the region of X ₀ of the evaporation material is a round shape, melted state of the evaporated substance in the entire X ₀ region Is big. When the acceleration voltage is larger than the standard voltage value V _0, the irradiation position of the electron beam on the evaporated substance is shifted to the near side (left side in the figure) in the direction perpendicular to the magnetic field direction, and the cross section is the direction of the magnetic field. It becomes a long ellipse in the direction perpendicular to. As shown in FIGS. 4B and 4C, this tendency becomes more significant as the acceleration voltage is increased. Therefore, when the acceleration voltage is V ₁ (V ₁ > V ₀ ), as shown in (b), the evaporated substance is dissolved in the front half of the X ₀ region, and the degree of dissolution is at the standard time. It becomes smaller than comparison. When the acceleration voltage is V ₂ (V ₂ > V ₁ ), as shown in (c), the evaporated substance is melted at a quarter of the area before X ₀ , and the degree of melting is further reduced. . On the other hand, when the acceleration voltage is made smaller than the standard value V _0, the irradiation position of the electron beam on the evaporating substance is shifted to the rear side (right direction in the figure) in the direction perpendicular to the magnetic field direction, and the cross section is a magnetic field. It becomes a long ellipse in a direction perpendicular to the direction of. As shown in FIGS. 4D and 4E, this tendency becomes more significant as the acceleration voltage is decreased. Therefore, when the acceleration voltage is V ₃ (V ₃ <V ₀ ), as shown in (d), the evaporated substance is melted in the rear half of the X ₀ region, and the degree of melting is the standard. Smaller than When the acceleration voltage is V ₄ (V ₄ <V3), as shown in (e), the evaporated substance is melted in the rear quarter portion of the X ₀ region, and the degree of melting is further reduced. In this way, if the acceleration voltage is changed and the degree of evaporating substance melting in a specific region on the evaporating substance is measured, how much the magnetic field strength changes with respect to the acceleration voltage value, the standard state (Fig. It can be seen whether the state (a) is approached. In this way, the correction intensity (excitation current value) of the magnetic field with respect to the acceleration voltage value is obtained and tabulated, and stored in the memory 23. The correction intensity value of the magnetic field corresponds to the correction excitation current value to the correction electromagnetic coil 20.
[0022]
In the apparatus having such a configuration, for example, when the acceleration voltage is set to the standard value V ₀ , the electron beam generated from the filament 6 of the electron gun 5 is accelerated by the anode 8, and the grid 7 and anode It passes through 8 beam passage holes 7H and 8H. At this time, the opening angle of the electron beam is determined by the beam passage holes 7H and 8H of the grid 7 and the anode 8. Then, the electrons exiting the beam passage hole 8H of the anode 8 are irradiated to the evaporating substance 3 which is bent around 270 ° and accommodated in the crucible 4 so as to draw a Ramor circle by the magnetic field generated by the magnetic poles 1A and 1B. At this time, since the electron beam from the electron gun 5 passes through the two-dimensional scanning magnetic field created by the scanning electromagnetic coil body 12, the electron beam scans the evaporation substance 3 in the two-dimensional direction. As a result, the evaporating substance 3 is heated by the electron beam to evaporate, and the evaporated particles adhere to, for example, each substrate (not shown) disposed above the crucible 4.
[0023]
In such an electron beam evaporation apparatus, as described above, evaporated particles adhere to the magnetic pole and the like, so these parts are sometimes disassembled and cleaned. Then, after cleaning, the parts are assembled and the apparatus is operated again. Prior to this reactivation, the electron beam is accelerated with the standard value V ₀ maintained, and the electron beam is applied to a specific area of the evaporated substance (in this case, the electron beam is not scanned). Measure the degree of melting. Then, the excitation current value to the correction electromagnetic coil 20 is changed so that the melting condition approaches the melting condition in the standard state before parts assembly, and the melting condition in the specific region is the same as the standard condition. This excitation current value is the set value after parts assembly. The excitation current is changed by inputting excitation current value data using a keyboard (not shown) connected to the control device 22. Therefore, after assembling parts such as magnetic poles after cleaning, it is not necessary to perform precise adjustment of the mounting position of the magnetic poles, etc., and the working efficiency is extremely improved.
[0024]
When an acceleration voltage different from the standard value is applied from the acceleration power source 10 between the anode 8 and the filament 6 according to a command from the control device 22, the control device 22 applies the excitation given to the set acceleration voltage value. Current correction value data is called from the memory 23, and a command is sent to the excitation power source 21 so that the standard excitation current plus this correction value flows to the correction electromagnetic coil 20. Thereby, the magnetic field by the magnetic poles 1A and 1B to be changed based on the acceleration voltage set this time is corrected to the standard state, and as a result, the deposited film on the substrate group (not shown) provided above the crucible The thickness becomes uniform.
[0025]
In the above example, an apparatus including an electron gun that deflects an electron beam around 270 ° is shown, but it is needless to say that the present invention is not limited to such an electron gun.
[0026]
In the above example, since the magnetic pole plates 1A and 1B are excited by the permanent magnet 2, the magnetic field formed between the magnetic pole plates is fixed, and a new correction is made to correct the strength of the magnetic field. The electromagnetic coil 20 is provided, but the magnetic pole plate may be excited by an electromagnetic coil, and a correction exciting current may be supplied to the electromagnetic coil that excites the magnetic pole plate.
[Brief description of the drawings]
FIG. 1 shows a schematic example of a conventional electron beam evaporation apparatus.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 shows a schematic example of an electron beam evaporation apparatus according to the present invention.
4 is a diagram for assisting in understanding the operation of the apparatus shown in FIG. 3; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1A, 1B ... Magnetic pole plate 2 ... Permanent magnet 3 ... Evaporation substance 4 ... Crucible 5 ... Electron gun 6 ... Filament 7 ... Grid 8 ... Anode 7H, 8H ... Beam passage hole 9 ... Filament heating power supply 10 ... Acceleration power supply 11 ... Grid support Plate 12 ... Scanning electromagnetic coil body 13 ... Scanning power supply 20 ... Correction electromagnetic coil 21 ... Excitation power supply 22 ... Control device 23 ... Memory

Claims (2)

A crucible containing an electron gun and an evaporating substance is provided between at least one pair of deflecting magnetic poles, and an electron beam emitted from the electron gun is deflected by a magnetic field formed by the deflecting magnetic pole to form an evaporating substance in the crucible. In an electron beam evaporation apparatus, wherein a scanning deflector is provided on the electron beam path so as to scan the evaporated material with an electron beam, it is formed between the deflection magnetic poles. An electromagnetic coil capable of magnetically affecting the magnetic field generated and capable of forming a new magnetic field in a direction parallel to the direction of the magnetic field is provided, and the electromagnetic coil according to the acceleration voltage value of the electron beam formed as but the angle of the electron beam incident on the evaporation material by controlling the magnetic field formation is the magnetic field strength control of the deflection magnetic pole is formed to a predetermined value Electron beam evaporation apparatus characterized by a. The magnetic field intensity correction data for correcting the deviation of the electron beam incident angle with respect to each acceleration voltage value different from the standard acceleration voltage value at which the angle of the electron beam incident on the evaporating material becomes a predetermined value is associated with each acceleration voltage value. 2. The electron beam evaporation apparatus according to claim 1 , further comprising a stored memory .

Images