JP2001192827A - Vacuum evaporation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deposit, continuously over a long time, a mixed film consisting of a plurality of elements so that composition ratio becomes uniform in the traveling direction and orthogonal direction of an object to be subjected to vapor deposition and in the direction of a film and thickness becomes constant in the traveling direction and the orthogonal direction. SOLUTION: The system is a vacuum evaporation system capable of depositing a mixture film consisting of different elements at least on one side of an object to be subjected to vapor deposition traveling through a vacuum chamber and is provided with: a crucible (individual evaporation sources) in which a plurality of evaporation materials of dissimilar compositions are filled alternately into respective regions divided in the traveling direction (sheet-width direction) of the object to be subjected to vapor deposition; and an electron gun for heating the evaporation materials. Further, this system has a temperature measuring means, an evaporation rate estimating means, an applied energy determining means, a controlled variable computing means, and an electron gun controlling means, on the basis of the ratio among the results obtained by the above means, for the individual evaporation sources.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vapor deposition apparatus for forming a vapor deposition thin film on an object running in a vacuum chamber.

[0002]

2. Description of the Related Art Conventionally, as a vacuum deposition apparatus for depositing a deposition thin film on an object to be deposited traveling in a vacuum chamber, for example, Japanese Patent Application Laid-Open No.
There is an apparatus described in JP-A-236273. In this device, a rectangular evaporation source is arranged (longer than the width of the film) so that the longitudinal direction is perpendicular to the running direction of the film. The deposition source is irradiated with an electron beam from a non-scanning electron gun and heated to form a thin film on the film. And when irradiating the electron beam from the electron gun,
The magnetic field is controlled so that the electron beam has the same incident angle at each position of the evaporation source.

However, this apparatus has no means for controlling the thickness of the deposited thin film. Therefore, for example, when the degree of vacuum in the vacuum chamber changes, or when the deposition rate changes due to a change in the surface shape of the deposition material, the thickness of the thin film is increased with respect to the running direction of the film and the direction perpendicular thereto. There was a problem of fluctuation. Furthermore, this apparatus cannot simultaneously deposit a plurality of deposition materials,
There is a problem that these mixed films cannot be formed on the film.

As a vacuum evaporation apparatus invented to solve such a problem, for example, a detector for detecting a part of the evaporation amount when an evaporation source in a vacuum chamber is heated by an electron gun, and a detector for detecting a part of the evaporation amount And means for controlling the output of the evaporation source based on the detected value of the evaporation source. This type of detector is provided with a crystal oscillator, and utilizes the principle that, when a deposited film adheres to the crystal oscillator, the oscillation frequency varies depending on the film thickness. This vacuum vapor deposition apparatus can indirectly control the thickness of a thin film formed on a film using a part of the amount of evaporation from an evaporation source as a control index.

[0005] However, when the above-mentioned detector is used to simultaneously deposit a plurality of deposition materials having different chemical compositions,
The detected signal cannot be decomposed into each component information. As a result, there has been a problem that the accuracy of controlling the composition ratio and the thickness is significantly reduced. Furthermore, because the indirect control is performed, for example, when the direction of the electron beam at the time of vapor deposition changes, the measured value of the adhesion amount of the detector may differ from the actual adhesion amount of the thin film. In addition, the above-described detector requires measures such as switching the detector during the measurement when performing long-time continuous measurement due to the limitation of the total deposition amount on the detector, and there is also a problem in the reliability of the measurement. was there.

As an apparatus which has solved such a problem, for example, there is an apparatus described in Japanese Patent Application Laid-Open No. Hei 1-208465. This apparatus includes an electron gun for exciting an characteristic X-ray by injecting an electron beam at an acute angle into a vapor-deposited film on a substrate after vapor deposition, a detector for measuring the characteristic X-ray intensity, and a detector for measuring the characteristic X-ray intensity. Means for controlling the output of each evaporation source based on the detected value. In this apparatus, since the direct measurement of the deposited thin film is possible, the production efficiency is improved as compared with the above-described apparatus.

However, since the above-mentioned electron gun makes a high-energy electron beam (RHEED) incident on the deposited film at an acute angle,
From the excited characteristic X-rays, only information on the very surface layer of the deposited thin film can be obtained. For this reason, there is a problem in that information on the entire film direction of the vapor-deposited thin film necessary for keeping the thickness constant cannot be obtained. Further, there is another problem that the surface of the deposited thin film irradiated with the high energy electron beam is damaged.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to continuously form a mixed film composed of a plurality of elements for a long period of time with a composition ratio of an object to be deposited. It is formed so as to be uniform in the running direction, the orthogonal direction and the film direction, and to have a constant thickness in the running direction and the orthogonal direction.

[0009]

The above object is achieved by the invention described in the claims. That is, the vapor deposition apparatus according to the present invention is a vacuum vapor deposition apparatus capable of forming a mixed film composed of different elements on at least one surface of a substance to be deposited traveling in a vacuum chamber, and the traveling direction of the substance to be deposited (hereinafter, a sheet). A crucible (hereinafter, referred to as individual evaporation sources) in which a plurality of deposition materials having different compositions are alternately filled in a region divided into width directions (hereinafter, referred to as individual evaporation sources), and an evaporation device provided with an electron gun for heating the deposition materials. A temperature measuring means for measuring the temperature of each evaporation source in a non-contact manner; an evaporation rate estimating means for estimating the evaporation rate of each evaporation source based on the measured temperature data; Comparing the speed with a reference value set in advance for each evaporation source, input energy determining means for determining the amount of energy to be input to each evaporation source based on the comparison result, Sum value A first control amount calculating means for determining the output of the electron gun based on the first control amount; a second control amount calculating means for determining the electron beam irradiation time of each evaporation source based on the ratio of the amount of energy to be input; An electron gun control means for applying the first and second control amounts to the electron gun and controlling the heating of the individual evaporation sources is provided.

According to this configuration, since the surface temperature of each evaporation source can be measured with time, the evaporation rate from each evaporation source at that time can be obtained from the measured value.
Furthermore, based on these evaporation rates, the amount of energy input to each evaporation source can be calculated with high precision and the electron gun can be automatically controlled, so that a mixed film composed of a plurality of elements can be continuously formed for a long time. It can be formed so that the composition ratio is uniform in the running direction, the orthogonal direction, and the film direction of the deposition target, and the thickness is constant in the running direction and the orthogonal direction. Therefore, a mixed film having a target composition ratio, a target thickness, and a uniform composition in the film direction can be continuously formed over the entire width of the sheet.

[0011]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic structure of a vacuum evaporation apparatus according to the present embodiment. In this vacuum vapor deposition apparatus, a film such as polyethylene terephthalate (PET) was used as an example of a material to be vapor-deposited. The material of the object to be deposited is not particularly limited. The film 17 set on the unwinding roll 1 of the vacuum chamber 6 travels on the cooling roll 3, passes through the near roll 5, and is wound by the winding roll 2.
The degree of vacuum in the vacuum chamber 6 is maintained at a predetermined degree by an exhaust system 10 including an oil diffusion pump (not shown).

A crucible 9, which is an example of a holding means for holding the vapor deposition material 16 at the bottom of the vacuum chamber 6, irradiates the vapor deposition material accommodated inside the crucible 9 with irradiation conditions of the electron beam (the electron gun and the electronic material). Distance, etc.) as much as possible. Further, the crucible 9 has a moving film 17.
1 can be approached or separated from the electron gun 4 in FIG. 1 so that the evaporation conditions can be kept constant with respect to the surface to be evaporated. The electron gun 4 is composed of the evaporation material 16 stored in the crucible 9.
Is irradiated with an electron beam 18. A part of the evaporation material heated and evaporated by the electron beam 18 is evaporated on the surface of the film 17 running on the cooling roll 3. In addition,
When the total energy input to the crucible 9 cannot be secured by one unit or when a wide film is deposited, a method of dividing the deposition region using a plurality of electron guns may be employed. The number of installed guns is not particularly limited.

Next, an infrared sensor 7 for measuring the temperature of each evaporation source will be described. An infrared sensor is installed in the atmosphere outside the vacuum chamber 6 and a quartz glass window 1 is provided.
In order to reliably receive infrared rays emitted from each of the vapor deposition materials via No. 1, they are arranged at 100 mm intervals on a straight line in the film width direction. FIG. 6A shows an example of the arrangement. The arrangement interval, the number of arrays, and the number of units may be determined according to the number and intervals of the evaporation sources, and are not particularly limited. If the airtightness of the sensor head can be ensured, the temperature may be measured by placing the sensor head in the vacuum chamber 6 without any particular limitation. The infrared energy detecting element 7a of this infrared sensor is a semiconductor (S
i) The detector has a detection wavelength of 0.9 to 1.0 μm.
Infrared rays emitted from individual evaporation sources are condensed by a lens, guided to a detection element 7a, converted into an electric signal by a controller 7b, and converted into a temperature signal.
Send to This signal is converted into the evaporation rate of each evaporation source based on the relational expression between the temperature and the evaporation rate set in advance in the experiment shown in FIG.

Here, the infrared sensor 7 and the evaporation rate calculator 12 constitute online monitoring means. The control amount calculator 13 collects evaporation rate data of each evaporation source.
Then, the input energy amounts of the individual evaporation sources are obtained based on a preset relational expression between the evaporation rate and the input energy amount.

Further, a reference value set in advance for each evaporation rate of each evaporation source is compared with a calculated value, a deviation amount is obtained, and a control PID (proportional operation Proporous operation) is determined based on the deviation amount.
tinal, integral operation lntegral, differential operation Derivative) is performed to correct the amount of energy input to each evaporation source in order to keep the deposited film uniform. The control amount calculator 13 determines the power (electric power) of the electron gun from the total amount of energy of the individual evaporation sources, and further determines the time for irradiating each evaporation source with an electron beam from the energy amount ratio of each evaporation source. Is determined by the following method. Since the energy supplied to each evaporation source is the electron beam 18 emitted from the same electron gun 4, the energy is actually applied to each material by changing the irradiation time of the electron beam for each evaporation source. The input energy can be distributed. Equation 1 shows these relational expressions.

[0016] In _{ta n = Pa n / (ΣPa} + ΣPs) × t0 above equation, ta _n electron beam scanning time at block n of aluminum oxide, amount of energy Pa _n to be introduced into the aluminum oxide block n, ShigumaPa is Total energy input to a total of 4 blocks of aluminum oxide,
ΣPS is the total energy input to a total of 4 blocks of silicon oxide, and t0 is the time constant (ms) depending on the hardware
It is.

The control data (power of the electron gun and electron beam irradiation time) is sent to the electron gun controller 14. The electron gun controller 14 controls the power supplied to the electron gun 4 and the irradiation time of the electron beam according to the input control data. Here, the control amount calculator 13 and the electron gun controller 14 constitute control means.

Incidentally, the plurality of infrared sensors are constituted independently of the on-line monitor means (not shown), and are constituted commonly by the control means. In the present invention, an infrared sensor having a semiconductor detector of Si is used as a means for measuring the temperature of each evaporation source.
As infrared sensor may be used, such as an optical fiber.
A method of measuring the temperature from the scattered light intensity by radiating a laser pulse to the laser beam or a method of measuring the temperature distribution of each vapor deposition source with one infrared camera as shown in FIG. Not even. Further, the method of calculating the input energy of each evaporation source from the calibration curve and the above formula for distributing the energy of the electron gun to each evaporation source are not particularly limited.

[0019]

EXAMPLES The embodiments of the present invention will be described below with reference to examples, but are not limited thereto. (Example 1) A polyethylene terephthalate (PET) film (Toyobo Co., Ltd.) was used as the sheet 17 to be deposited.
E5100: trade name).

As an evaporation material (evaporation source), aluminum oxide (Al 2 O) in the form of particles having a size of about 3 to 5 mm is used.
3, purity 99.5%) and silicon oxide (SiO2, purity 9)
9.9%). One crucible holding these materials was made of copper, and had a structure in which a cooling water cooling tube 20 having an outer diameter of 20 mmΦ was provided at the bottom. Cooling water flow rate is about 4m ³ / h
It is.

In this crucible 9, 2 mm-thick carbon stripping plates 19 are arranged at intervals of 100 mm in the width direction in order to alternately arrange the vapor deposition materials in a line facing the film width direction. The structure is such that materials can be stored. The partition plate 19 is used to hold an electron beam 1 of an electron gun 4 described later.
8 are arranged to be inclined at an angle substantially equal to the incident angle on each deposition material. The two types of vapor deposition materials were alternately and uniformly stored in each block secured by the partition plate 19. 2 and 3 show a schematic structure of the crucible 9 used in this embodiment.

One electron gun 4 having a power of 250 kW was disposed at the center of the film width direction. This electron gun 4
According to the specification, a total of 8 blocks of the vapor deposition material were deposited, with 4 blocks of SiO _{2 and} 4 blocks of Al ₂ O ₃ alternately arranged in the crucible.

The evacuation system was designed so that the pressure in the vacuum chamber during vapor deposition could always be kept at 4 × 10 ⁻⁴ Pa or less. In particular,
The structure was such that a 50000 L / sec oil diffusion pump was directly connected to the bottom of the vacuum chamber.

The infrared sensor 7 for measuring the temperature of each deposition source uses a sensor having a detection element of Si, a measurement wavelength of 0.9 μm, and a spot diameter of φ12 mm (distance of 1000 mm). 100mm in the width direction of
8 units are arranged at equal intervals, and the distance to each evaporation source is
The temperature was continuously measured at 980 mm.

The distribution of gas evaporating from each evaporation block shows the evaporation characteristics of each evaporation material in the crucible. FIG. 5 shows 31 (evaporation component from silicon oxide block) and 32 (evaporation component from aluminum oxide block). As shown in ()), the distribution is such that the intensity is highest immediately above, and the intensity decreases as it spreads laterally. This distribution intensity and shape are the intensity of the electron beam,
It mainly depends on the angle at which the electron beam is incident, the distance between the electron gun and the crucible, and the evaporation area. Therefore, in order to form a thin film so that the composition ratio is uniform in the running direction, the orthogonal direction, and the film direction of the deposition target, and the thickness is constant in the running direction and the orthogonal direction, the arrangement of the evaporation material is important. It is.

The arrangement of the materials in this embodiment is shown in FIGS.
And the distance to the surface of the crucible closest to the electron gun was 1000 mm. In the figure, A and S are Al ₂ O ₃ ,
Indicates that SiO ₂ is stored. In addition, the vapor deposition material was divided and arranged by a thin partition plate shown in FIG.

The film 17 was deposited under the conditions described above. The running speed of the film is 300 m / min and a total of 40,0
00m was deposited. The crucible is 2mm toward the electron gun
/ Min (drive device is not shown). In order to confirm the effect of the automatic control, the case where the automatic control was performed and the case where the automatic control was not performed were compared. Table 1 shows the results. In addition, the vapor deposition thickness data to be compared was measured off-line using a fluorescent X-ray type thickness measuring instrument. It can be seen that when the automatic control is not performed, the total thickness fluctuation and the composition ratio fluctuation are large, but when the automatic control is performed, a very stable film is formed.

[0028]

[Table 1] [Other Embodiments] (1) In the above-described embodiment, an example in which a so-called one-chamber system is used as the vacuum chamber is described. The present invention is also applicable to a so-called two-chamber type apparatus in which vacuum evaporation is performed in this state.

(2) In the above embodiment, the example in which the unwinding roll and the take-up roll of the material to be vapor-deposited are arranged in the vacuum chamber has been described. However, the present invention can also be applied to a continuous apparatus in which vapor deposition is performed in a high vacuum chamber.

(3) In the above embodiment, a film is taken as an example of the sheet-like material to be deposited, but the material to be deposited may be paper, cloth, resin, metal, inorganic material or the like. Various elements and compounds other than the above-described aluminum oxide and silicon oxide can be used as the vapor deposition material, and a mixed film composed of two or more elements or components using two or more vapor deposition materials can be used. May be formed.

(4) In the above embodiment, the heating means is an electron gun. However, the present invention can be applied to a vapor deposition apparatus in which a crucible is heated by an induction heating coil.

[0032]

As described above, according to the present invention, a mixed film composed of a plurality of elements is continuously formed for a long period of time so that the composition ratio is uniform in the running direction, the perpendicular direction, and the film direction of the deposition target. In addition, a vacuum evaporation apparatus that can be formed so that the thickness is constant in the running direction and in the perpendicular direction can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a vacuum evaporation apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a crucible used in a vacuum evaporation apparatus according to an embodiment of the present invention and an arrangement thereof.

FIG. 3 is a view for explaining the structure of the crucible of FIG. 2;

FIG. 4 is a graph illustrating the relationship between the amount of energy supplied to the crucible and the film deposition rate, and a graph illustrating the relationship between the surface temperature of the evaporation source and the film deposition rate.

FIG. 5 is a graph illustrating the vapor deposition characteristics of each vapor deposition material block.

FIG. 6 is a diagram illustrating an arrangement method of an infrared sensor.

[Explanation of symbols]

 Reference Signs List 4 heating means 7a detection element (Si) 7b controller 8 holding means (crucible) 9 vapor deposition material 10 electron beam 19 threshold plate

Claims (1)

[Claims] 1. A vacuum deposition apparatus capable of forming a mixed film made of different elements on at least one surface of a deposition object running in a vacuum chamber, wherein the deposition direction is referred to as a sheet width direction. In a crucible (hereinafter, referred to as individual evaporation sources) in which a plurality of deposition materials having different compositions are alternately filled in divided regions, and in an evaporation apparatus having an electron gun for heating the evaporation material, Temperature measuring means for measuring the temperature of the evaporation source in a non-contact manner; evaporating rate estimating means for estimating the evaporation rate of each evaporation source based on the measured temperature data; Comparing the reference values set corresponding to the evaporation sources, input energy determining means for determining the amount of energy to be input to each evaporation source based on the comparison result, and a total value of the individual input energy amounts. Determine the output of the electron gun First control amount calculating means for performing the control, second control amount calculating means for determining the electron beam irradiation time of each evaporation source based on the ratio of the energy amounts to be input, and the first and second controls A vacuum evaporation apparatus having electron gun control means for controlling the heating of each evaporation source by giving an amount to an electron gun.