JPH07229796A - Surface temperature measuring method and device for molten substance - Google Patents

Abstract

PURPOSE:To provide a surface temperature measuring method and device for a molten substance in a vacuum container which can measure the surface temperature continuously at a high resolution. CONSTITUTION:A crucible 1 in which a molten substance 2 is filled is provided in a vacuum container 6, an electron beam 4 for heating is radiated from an electron gun 3 for heating on the outer side, the molten substance 2 is evaporated so as to generate a vapor 7, and the vapor 7 is deposited to an article 8 to be deposited. An electron beam 12 for measuring is radiated from an electron gun 11 for measuring, and when the beam 12 hits the molten substance 2, a bremsstrahlung X ray 19 is generated, and the profile of the X ray 19 is measured by an X-ray camera 13. Furthermore, in an image process device 17, the temperature is found from the variation amount of the image processed profile, because the variation amount of the profile depends on the surface temperature of the molten substance 2, and it is displayed on a temperature display device 18. Consequently, the surface temperature can be measured accurately continuously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the surface temperature of a molten substance in a vacuum container.

[0002]

2. Description of the Related Art FIG. 3 shows the concept of an apparatus including a conventional surface temperature measuring instrument in a vapor deposition apparatus. The molten substance 2 placed in the crucible 1 in the vacuum container 6 is heated and melted by the heating electron beam 4 generated from the heating electron gun 3.
In order to prevent the steam 7 from flowing into the heating electron gun 3, the heating electron beam 4 is installed at a position not directly looking at the molten substance 2 as shown in the drawing, and the heating electron beam 4 is moved to the crucible 1
After being deflected by the deflection coil 5 installed in the vicinity, it is made incident on the molten substance 2. Steam 7 is generated from the molten substance 2 at a steam pressure according to the surface temperature. By installing the vapor deposition plate 8 above the crucible 1, the vapor 7 can be vapor deposited on the vapor deposition plate 8.

For the purpose of controlling the evaporation rate of the vapor from the molten substance 2, it is necessary to grasp the surface temperature of the molten substance 2, but since the evaporation rate is determined by the vapor pressure, the surface temperature Measurement monitoring is required. For this purpose, in the conventional apparatus, an observation window 31 is provided in a part of the vacuum container 6, and the surface temperature is measured by a multi-wavelength type (single color, two colors, etc.) thermometer installed outside the window 31. . Note that if the observation window 31 is always arranged so as to face the molten material 2, vapor deposition of the vapor 7 interferes with the measurement, so in order to avoid the problem, (1) the rotary shutter 34 is only used during observation. An open method, (2) a method of observing the inside of the crucible 1 using reflection by a reflection mirror (not shown), and the like have been adopted.

[0004]

The multicolor thermometer which has been used to measure the surface temperature of a molten substance has the following problems.

(1) The following problems are caused by vapor deposition of vapor on the observation window and the reflection mirror. (A) The amount of light incident on the thermometer is reduced, which leads to deterioration of measurement sensitivity with time and, in turn, deterioration of observable life. Further, this makes it impossible to measure temperature continuously for a long time. (B) Since the absorbance of the deposit is wavelength-dependent, the emissivity or emissivity ratio set when using the multicolor thermometer device system changes with time, and thus the measurement accuracy fluctuates with time. .

(2) The position and range of the surface temperature measurement of the molten material are limited by the distance between the observation window and the molten material, the geometrical arrangement, and the lens system magnification of the multicolor thermometer device system used. . Generally, the distance between the observation window and the molten material must be increased for the purpose of reducing (a) the amount of vapor deposited on the observation window and (b) the amount of radiant heat received from the molten material. There was a problem of becoming.

[0007]

In order to solve such a problem, the present invention provides a method for measuring the surface temperature of a molten substance in a container, in which an electron for measurement is provided independently of an electron gun for heating the molten substance. The method of using the electron beam from the gun and the method of using the electron beam from the heating electron gun are used to measure the profiles of these electron beams, and the amount of change in this profile depends on the surface temperature of the molten material. To provide a method for measuring temperature by utilizing.

Further, as a device for measuring the surface temperature of a molten substance,
An independent electron gun is provided, the profile of the electron beam from this electron gun is measured by an X-ray camera, image processing is performed, the surface temperature is measured from the amount of change in the profile, and a means for displaying is provided. The electron beam from the electron gun is also used for the measurement, and the means for measuring and displaying the surface temperature by performing image processing, measuring with the camera, and displaying the same is also provided.

That is, according to the first aspect of the invention, in a method for measuring the surface temperature of a molten substance formed by heating a substance in a container, the substance is emitted from an electron gun device installed independently of the heating source of the molten substance. By utilizing the fact that the measuring electron beam is incident on the molten substance and the amount of change in the measuring electron beam profile caused by the scattering of the vapor generated from the molten substance depends on the temperature of the measuring electron beam incident part Provided is a method for measuring a surface temperature of a molten substance, which comprises measuring a temperature.

According to a second aspect of the present invention, in the method for measuring the surface temperature of a molten substance produced by heating a substance in a container, the electron beam emitted from the electron gun device for heating the molten substance is the same molten substance. The molten substance is characterized in that the temperature is measured by utilizing the fact that the amount of change in the electron beam profile caused by the scattering of the vapor generated from the molten substance upon incidence on is dependent on the temperature of the electron beam incident part. A method for measuring the surface temperature of a.

According to a third aspect of the present invention, in a temperature measuring device for measuring a surface temperature of a molten substance formed by heating a substance in a container, an electron gun device installed independently of the molten substance heating source, An X-ray camera for measuring the beam profile of the measuring electron beam emitted from the electron gun device on the molten material, and an image processing of the electron beam profile image measured by the X-ray camera to obtain a two-dimensional intensity distribution. And a temperature indicator for displaying the surface temperature of the molten substance calculated based on the electron beam profile image evaluated using the image processing device for the molten substance. A surface temperature measuring device is provided.

Further, as a fourth aspect of the present invention, in a temperature measuring device for measuring a surface temperature of a molten substance formed by heating a substance in a container, an electron gun device and an electron gun device also serving as the molten substance heating source. An X-ray camera for measuring a beam profile of an electron beam emitted from the molten substance on the molten material, an image processing device for image-processing an electron beam profile image measured by the X-ray camera to obtain a two-dimensional intensity distribution, A surface temperature measuring device for a molten material, comprising: a temperature indicator for displaying the surface temperature of the molten material calculated based on an electron beam profile image evaluated using the image processing apparatus. .

[0013]

The present invention is the above-mentioned means. In the first aspect of the invention, the measuring electron beam from the electron gun installed independently of the electron gun for heating the molten material impinges on the molten material. The profile of the incident electron beam changes due to scattering with the vapor generated from the molten material. The amount of change in the electron beam profile depends on the amount of vapor density and the electron beam path length in a significant scattering region, but since the vapor pressure of the vapor depends on the surface temperature of the molten material, the electron beam incident on the molten material The surface temperature can be evaluated from the amount of change in the beam profile by utilizing the fact that the beam profile in 1) depends on the surface temperature of the molten material.

Further, in the invention of claim 2, the electron beam for heating the molten substance is measured for measurement, and the fact that the electron beam profile depends on the surface temperature of the molten substance is utilized. The same effect as the invention of.

Further, the invention of claim 3 is an invention as an apparatus, wherein an electron beam profile on a molten substance of an electron beam for measurement from an electron gun independently installed for measurement is measured by an X-ray camera. The intensity distribution is two-dimensionally obtained from the profile by the image processing apparatus. Since this profile depends on the surface temperature of the molten material as in the case of the above-mentioned first aspect of the invention, it changes according to the change of the surface temperature. The temperature is obtained from this variation and displayed on the temperature display.

Further, in the invention of claim 4, instead of the measuring electron beam profile of the invention of claim 3 described above, an electron beam profile for heating the molten substance is used for measurement, and this is measured by an X-ray camera. I decided to do so,
The same effect as the invention of claim 3 is exerted. In this case, the temperature measurement position is limited to the position of the heating electron beam, but the measurement electron gun is not required, and the number of electron guns installed is reduced.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a surface temperature measuring apparatus for a molten substance according to an embodiment of the present invention. In the figure, 6 is a vacuum container having a crucible 1 containing a molten substance 2 therein,
A heating electron gun 3 is attached to which the heating electron beam 4 is incident from a part of the vacuum container 6. Reference numeral 5 is a deflection coil for deflecting the heating electron beam 4, and 7 is a heating electron beam 4.
The vapor of the molten substance 2 which is heated and vaporized by the reference numeral 8 is an object to be vapor-deposited.

Reference numeral 11 is a measuring electron gun attached to the outer surface of the vacuum container 6, 12 is a measuring electron beam emitted from the electron gun 11, 13 is an X-ray camera, and 14 is an X-ray camera 13.
A beryllium window for protecting the screen, 15 a shielding plate, 16 a beam profile monitor for inputting an image signal from the X-ray camera 13, 17 an image processing device, and 18 a temperature indicator for displaying the temperature obtained from the result of the image processing. Is. Reference numeral 19 is a braking X-ray, 21 is a TMP (main exhaust device) of the vacuum container 6, 2
Reference numeral 2 is an RP (auxiliary exhaust device).

In such an apparatus, the molten substance 2 installed in the crucible 1 is heated and melted by the electron beam 4 generated from the heating electron gun 3, and evaporated at a vapor pressure corresponding to the surface temperature of the portion, Steam 7 is generated. This crucible 1
The vapor deposition plate 8 is installed above, and the vapor 7 is vapor deposited on the vapor deposition plate 8.

The surface temperature of the molten substance 2 is determined by the following procedure. The measuring electron gun 11 is installed separately from the heating source. The measuring electron gun 11 is operated at a high acceleration voltage and a low output. This is because (1) the influence of thermal disturbance on the surface temperature to be measured is minimized, and (2) the braking X-ray dose used at the time of beam profile measurement depends on the accelerating voltage and the beam current. It depends on the dependence on the former being greater than on the latter.

When the electron beam 12 generated from the measuring electron gun 11 is made to enter the molten substance 2, the molten substance 2
The electron beam 12 profile is as follows according to the surface temperature of

(A) When the surface temperature of the molten substance 2 is low and the amount of vapor 7 generated is small; the incident electron beam 12 is vapor 7 because the amount of vapor 7 generated from the molten substance 2 is negligible.
Almost no scattering by. Therefore, the electron beam 12 profile is not affected by the vapor 7.

(B) When the surface temperature of the molten substance 2 is high and the amount of steam 7 generated is large; the amount of vapor 7 generated from the molten substance 2 increases due to the vapor pressure corresponding to the surface temperature, and thus influences scattering. When the vapor density or the like has a significant effect on the activation of the electron beam 12 before it is received, the beam profile of the incident electron beam 12 at the time of incidence on the molten substance 2 depends on the vapor density or the like, that is, It changes in accordance with the surface temperature of the molten substance 2 (width increases and peak value decreases).

When the electron beam 12 is incident on the molten material, the braking X-rays 19 are emitted in an amount corresponding to the material of the molten material, the energy of the incident electron beam, the amount of beam current and the like. From this, the profile of the braking X-ray 19 can be changed to the vacuum container 6
The profile of the incident electron beam 12 can be measured and evaluated by measuring with an X-ray camera 13 installed outside the. Here, the X-ray camera 13 is, for example, a device mainly composed of a pinhole optical system and a microchannel plate and capable of two-dimensionally detecting the braking X-ray 19 image emitted from the molten material 2 part when the electron beam 12 is irradiated. means. A beryllium window 14 is provided between the vacuum container 6 and the X-ray camera 13 for the purpose of maintaining a vacuum and suppressing the amount of braking X-ray dose reduction.

An image of the electron beam 12 measured by the X-ray camera 13 is image-processed by the image processing device 17, that is, a two-dimensional intensity distribution evaluation is performed to obtain an electron beam profile.

FIG. 3 shows an example of changes in the beam profile due to measurement of the beam profile. In this figure, two cases of measurement with and without the influence of scattering with vapor are shown at the same magnification. In the figure, (A) shows a change in the X-ray dose when there is an influence of scattering with vapor, (B) shows a case where the influence of scattering with vapor can be ignored, and (C) shows a background due to a heating electron beam. Are shown respectively. As described above, when the electron beam trajectory is affected by the influence of scattering, the electron beam shape is expanded as shown in (A). Therefore, the median absolute value / relative value or the change amount of both beam profiles and the full width half maximum absolute value / relative value or the change amount thereof correspond to the surface temperature of the molten substance 2.

The relation between the amount of change in beam profile and the surface temperature can be theoretically evaluated, for example, by performing scattering analysis by Monte Carlo simulation with the beam profile under the condition that almost no vapor is generated. Although it can be performed, generally, when an electron beam is used as a heating source in a vapor deposition apparatus or the like, the electron beam 4 for heating is deflected by a deflection coil 5 installed in the vicinity of the crucible 1 as shown in FIG. Therefore, the trajectory of the incident electron beam 12 is the deflection coil 5 concerned.
Since it is also affected by the magnetic field due to the magnetic field, it is more accurate to compare the surface temperature measurement value using a multicolor thermometer with the beam profile change amount in advance in the equipment system used for more accurate surface temperature evaluation. Can be expected.

In the X-ray camera 13, the measuring electron beam 1
The braking X-ray image by the heating electron beam 4 is also captured in addition to the braking X-ray image by 2. However, the general commercial heating electron gun accelerating voltage is 40 keV or less in order to avoid the problem of braking radiation. Since the bremsstrahlung dose has a higher dependence on the accelerating voltage, it is possible to separate the two images by setting the measuring electron beam to have a high accelerating energy. For example, literature data (S.Sc
hiller et al .: ELECTRON BEAM TECHNOLOGY (1982 Wil
ey-Interscience Pub.) p33), 100kV,
Electron beam of 0.1 A (10 kW) and 40 kV, 10 A (4
The braking X-ray dose of the electron beam (00 kW) is 300: 10, which does not cause any particular problem as the measurement system S / N ratio.

It is necessary to install a shield plate 15 or the like between the beryllium window 14 and the molten substance 2 in the vacuum container 6 in order to avoid the inflow of the vapor 7 into the X-ray camera 13.
Even if the vapor 7 is vapor-deposited on the shielding plate 15, in the electron beam profile measurement by the X-ray camera 13, the absolute value of the beam intensity changes, but this does not affect the evaluation of the full width at half maximum, etc. The electron beam has a lifetime corresponding to the amount of vapor deposition so that the electron beam can be observed.

Further, by using a measuring spot having a small diameter as the measuring electron beam 12 to be used, it becomes possible to carry out a measurement with a higher position resolution than a multicolor thermometer or the like used conventionally. . The position resolution in this case is (1) the diameter of the measuring electron beam 12 used,
It is determined by (2) the measurement resolution of the X-ray camera and (3) the position resolution of the multicolor thermometer when the calibration is performed by the multicolor thermometer.

Although specific examples of the apparatus using the present invention have been described above, the measuring electron gun does not necessarily have to be different from the heating electron gun. The same measurement can be performed by using only the braking X-rays emitted by irradiating the heating electron beam. However, in this case, although the number of required electron gun devices can be reduced and the background of the measurement electron beam is low, the temperature measurable position is limited to only the position where the electron beam is irradiated. Will end up.

[0032]

As described above in detail, in the present invention, the electron beam for measurement is emitted to the molten metal and the electron beam profile thereof is measured, or the electron beam for heating is used instead of the electron beam for measurement. The surface temperature measurement method that utilizes the fact that the profile change is dependent on the surface temperature of the electron beam incident part and that profile is measured with an X-ray camera Since the device for measuring the surface temperature is used by utilizing the dependence on the surface temperature, the following effects can be obtained as compared with a thermometer which has been conventionally used for the purpose of measuring the surface temperature of a molten substance or the like.

(1) It has a long life and there is almost no change in measurement accuracy over time. Therefore, the surface temperature of the molten material can be continuously measured for a long time.

(2) It is possible to increase the measurement position resolution.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a surface temperature measuring device for a molten substance according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a beam profile measurement result according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional surface temperature measuring device for molten substances.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 crucible 2 molten substance 3 electron gun for heating 6 vacuum container 7 vapor 8 vapor deposition object 11 electron gun for measurement 12 electron beam for measurement 13 X-ray camera 14 beryllium window 17 image processor 18 temperature indicator 19 braking X-ray

Claims (4)

[Claims] 1. A method for measuring a surface temperature of a molten substance formed by heating a substance in a container, wherein a measuring electron beam emitted from an electron gun device installed independently of a heating source of the molten substance is used. The temperature is measured by utilizing the fact that the amount of change in the electron beam profile for measurement that is incident on the molten substance and is caused by scattering by vapor generated from the molten substance depends on the temperature of the electron beam incident portion for measurement. A method for measuring the surface temperature of a molten substance. 2. A method for measuring a surface temperature of a molten substance formed by heating a substance in a container, wherein when an electron beam emitted from the electron gun device for heating the molten substance is incident on the molten substance, A method for measuring a surface temperature of a molten substance, characterized in that the temperature is measured by utilizing the fact that the amount of change in the electron beam profile caused by scattering by the vapor generated from the molten substance depends on the temperature of the electron beam incident part. 3. A temperature measuring device for measuring a surface temperature of a molten substance formed by heating a substance in a container, wherein an electron gun device provided independently of the molten substance heating source and emitted from the electron gun device. X-ray camera for measuring the beam profile of the measuring electron beam on the molten material,
Image processing apparatus for image-processing an electron beam profile image measured by a line camera, and a surface of the molten substance calculated based on the electron beam profile image evaluated by the image processing apparatus A surface temperature measuring device for a molten substance, comprising: a temperature indicator for displaying the temperature. 4. A temperature measuring device for measuring a surface temperature of a molten substance formed by heating a substance in a container, wherein an electron gun device also serving as the molten substance heating source, and an electron beam emitted from the electron gun device. An X-ray camera for measuring a beam profile on the molten substance, an image processing apparatus for image-processing an electron beam profile image measured by the X-ray camera to obtain a two-dimensional intensity distribution, and the image processing apparatus. A surface temperature measuring device for a molten material, comprising: a temperature indicator for displaying the surface temperature of the molten material calculated based on the evaluated electron beam profile image.