JP2013104085A - Film thickness sensor device for electron beam deposition - Google Patents

Abstract

A quartz-vibration type film thickness sensor device capable of normal operation over a long period of time is provided.
When a thin film is formed by adhering a material 7 irradiated with accelerated electrons, heated and evaporated, to the surface of a substrate film 2 while shielding the electrons by the formed magnetic field, the thickness of the thin film is obtained. This is a crystal vibration type film thickness sensor device 10. A rotating body 12 having a slit is disposed between the film thickness sensor 11 and the material 7. A magnet for generating a magnetic field is provided in a direction crossing the longitudinal direction of the slit.
[Effects] Since it is possible to effectively shield the electrons that adversely affect the vibration of the crystal resonator from being incident on the film thickness sensor, normal operation can be performed over a long period of time.
[Selection] Figure 1

Description

  The present invention relates to a film thickness sensor device suitable for a vapor deposition apparatus using an electron beam.

  In the vapor deposition apparatus using an electron beam, electrons accelerated at a predetermined voltage are evaporated by irradiating and heating the material in the crucible arranged in the vacuum vessel, and the evaporated material is arranged in the vacuum vessel. A thin film is formed by adhering to the surface of a substrate which is a vapor deposition member.

  Not only a vapor deposition device using such an electron beam, but also a quartz type that measures the change in frequency due to the deposition material adhering to the crystal unit as a sensor for grasping the thickness of the thin film deposited on the surface of the substrate. A film thickness sensor is generally used (for example, Patent Document 1).

  However, when a quartz film thickness sensor is used in a vapor deposition apparatus that uses an electron beam, the reflected electrons after irradiation on the material in the crucible and the electrons that have moved off the trajectory will adversely affect the vibration of the crystal unit. Will not work properly.

  In addition, there is a problem that the life of the quartz crystal unit is significantly reduced due to damage to the crystal unit due to the reflected electrons and the electrons deviating from the orbit, and accumulation of a large amount of vapor deposition material.

  Therefore, conventionally, in order to reduce the amount of electrons incident on the film thickness sensor, the film thickness sensor has been moved away from the material in the crucible, or a grid has been installed between the film thickness sensor and the crucible. A sufficient effect could not be obtained.

  In addition, as a measure to increase the lifetime of the film thickness sensor, there is a method to cope with by installing a plurality of crystal resonators in the vacuum chamber in advance and switching to a new crystal resonator before the end of its life, In this method, a plurality of crystal resonators are required, and a switching mechanism is required.

JP 2004-231991 A

  The problem to be solved by the present invention is that the film thickness sensor is moved away from the material in the crucible or a grid is installed between the film thickness sensor and the crucible in order to reduce the amount of electrons incident on the film thickness sensor. However, a sufficient effect cannot be obtained.

  In addition, a method of installing a plurality of crystal units in a vacuum chamber and switching to a new crystal unit before the end of its life requires a plurality of crystal units and a switching mechanism. It is.

The film thickness sensor device for an electron beam evaporation apparatus of the present invention is
To enable normal operation over a long period of time,
A quartz-vibration film thickness sensor device that obtains the thickness of the thin film when the thin film is formed by attaching a material evaporated and heated by accelerating electrons to the substrate surface,
The main feature is that a rotating body having a slit is disposed between the film thickness sensor and the material, and magnetic field generating means for generating a magnetic field in a direction crossing the longitudinal direction of the slit is provided.

  The film thickness sensor device for an electron beam vapor deposition apparatus according to the present invention has a rotating body having a slit between the film thickness sensor and the material, so that electrons incident on the film thickness sensor can be effectively shielded, Normal operation can be continued for a long period of time.

  Further, since the magnetic field generating means for generating the magnetic field in the direction intersecting with the longitudinal direction of the slit is provided to form the magnetic field in the slit, the output of the film thickness sensor is stabilized in addition to the above effect.

  In the film thickness sensor device for an electron beam evaporation apparatus according to the present invention described above, when the width of the slit is made narrower than the width of the film thickness sensor, electrons that are about to enter with a weak magnetic field can be shielded.

  In the present invention, by arranging a rotating body having a slit between the film thickness sensor and the material, it is possible to effectively shield the incidence of electrons, which adversely affect the vibration of the crystal resonator, on the film thickness sensor. Even if a plurality of crystal units are not installed and replaced, normal operation can be performed over a long period of time.

It is the figure which showed the state which installed the film thickness sensor apparatus of this invention in the electron beam vapor deposition apparatus. (A) is the figure which looked at the rotary body from the front, (b) is an enlarged view of the slit part of (a) figure.

  In the present invention, the object of enabling normal operation over a long period of time is realized by arranging a rotating body having a slit between the film thickness sensor and the material.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to FIGS. 1 and 2.
First, after describing the schematic configuration of the electron beam evaporation apparatus, the film thickness sensor apparatus of the present invention installed in the electron beam evaporation apparatus will be described.

  In FIG. 1, reference numeral 1 denotes a vacuum container, and a substrate film 2 on which a thin film is formed is disposed above the inside of the vacuum container 1. The substrate film 2 is wound, for example, on an unwinding roll 3a, wound on a cooling roll 3d via an idle roll 3b and a tension control roll 3c, and then wound on a winding roll 3e via a tension control roll 3c and an idle roll 3b. Rolled up.

  Reference numeral 4 denotes an adhesion-preventing plate that covers the lower half of the cooling roll 3d except for the film formation range. The material 7 in the crucible 6 heated and evaporated by the collision of the electrons is deposited to form a thin film. 1 is a magnet that bends the path of electrons emitted from the electron gun 5 and guides it into the crucible 6 at the ground potential.

  9, in order to prevent the reflected electrons after irradiation of the material 7 in the crucible 6 and the electrons deviating from the trajectory from entering the film forming range and inhibiting the deposition of the material 7 on the substrate film 2. The magnets are arranged between the film forming range of the cooling roll 3d and the electron gun 5, the crucible 6 and the magnet 8. For example, four magnets are arranged in a lattice shape with a predetermined interval in the traveling direction of the substrate film 2. It is installed.

  The present invention is a film thickness sensor device 10 for determining the film thickness of a thin film formed on a substrate film 2 using the electron beam vapor deposition apparatus having the above configuration, and employs the following configuration.

  Reference numeral 11 denotes a quartz vibration type film thickness sensor provided until the material 7 in the evaporated crucible 6 is deposited on the substrate film 2, and measures the change in the frequency caused by the deposition material adhering to the quartz resonator. Thus, the thickness of the thin film formed on the substrate film 2 is obtained.

  Reference numeral 12 denotes a rotating body made of a material (for example, stainless steel, copper, etc.) capable of shielding electrons such as reflected electrons disposed between the film thickness sensor 11 and the material 7, for example, as shown in FIG. Thus, the same slit 12a is formed at a position rotated 180 ° in the circumferential direction.

  As shown in FIG. 2, the longitudinal direction of the slit 12 a has a length L 1 that is equal to or larger than the diameter of the film thickness sensor 11, and is at a position facing the incident surface of the material 7 in the film thickness sensor 11. Is formed.

  There is no problem in measuring the film thickness of such a rotating body 12 by taking into account the width of the slit 12a by a rotating mechanism (not shown) (accuracy equivalent to that of a normal quartz vibration film thickness sensor 11). By rotating at the minimum number of rotations), the reflected electrons after irradiation on the material 7 in the crucible 6 to be incident on the film thickness sensor 11 and the electrons deviating from the orbit are effectively shielded. And normal operation can be continued for a long period of time.

  13 is a magnetic field generating means, for example, a magnet, which is provided in parallel with the slit 12a and intersects the longitudinal direction of the slit 12a. The magnet 13 forms a magnetic field over the entire longitudinal direction in the slit 12a. The reflected electrons and the electrons deviating from the orbit are shielded from entering the slit 12a. The length L2 of the magnet 13 provided in parallel with the slit 12a is set to be not less than the length L1 in the longitudinal direction of the slit 12a.

  The magnetic field is generated in a direction intersecting the longitudinal direction of the slit 12a, and the magnetic flux density in the slit 12a is 6 mT or more and 10 mT or less in consideration of the electron shielding effect and the influence of the magnetic field on the film thickness sensor 11. Like that.

  When such a magnet 13 is provided, a magnet with a weak magnetic field necessary for shielding electrons between the slits 12a is provided as compared with the case where a magnet is provided in the vicinity of the film thickness sensor 11 independently of the rotating body 12. As a result, the influence of the magnetic field on the film thickness sensor 11 is reduced, and in addition to the above effect, the output of the film thickness sensor 11 is stabilized.

  By the way, when the length in the width direction of the slit 12a is made smaller than the width B of the film thickness sensor 11 within a range that does not hinder measurement of the film thickness, for example, as shown in FIG. Even if the magnetic field of the magnet 13 is weak, the sufficient shielding effect can be obtained.

  By the way, when using the electron beam vapor deposition apparatus having the configuration shown in FIG. 1 and continuously depositing Al on the substrate film 2 under the following conditions, the frequency of the crystal resonator is measured using the following film thickness sensor apparatus. As a result, the following results were obtained. In addition, according to the past results, a film thickness sensor that can be used up to 4.3 MHz is employed for resistance heating vapor deposition of Al.

(Deposition conditions)
・ Acceleration voltage: 2kV
・ Emission current: 300mA
・ Vapor deposition rate on the crystal unit of the film thickness sensor: 5nm / sec
-Expected frequency of crystal unit: 5MHz

(Conventional example)
When the rotating body is not installed, the frequency of the crystal unit decreases to 4.95 MHz in about 10 minutes, and the reflected crystal after irradiation of the material in the crucible and the orbit of the crystal unit due to the incidence of the electrons that deviate from the trajectory The output has become unstable due to the adverse effects on vibration, making it unusable.

Example 1
A rotating body without magnets, in which two slits having a width of 10 mm at the position where the distance from the rotation center of the rotating body to the center of the slit is 50 mm and two positions at the position shown in FIG. 2A, was rotated at 120 rpm.

  As a result, the amount of vapor deposition material incident on the film thickness sensor is about 1/16 compared to the conventional example, and the output becomes unstable and cannot be used. The frequency of the crystal unit is reduced to 4.95 MHz. It took about 160 minutes and the sensor life was about 16 times longer.

(Example 2)
A ferrite magnet (with a minimum magnetic flux density of 6 mT or more and 10 mT or less in the slit) is provided in parallel with the slit of the rotating body of Example 1 and rotated at 120 rpm as in Example 1. The frequency was reduced to 4.95 MHz, but the output was stable. After that, it could be used in a stable state for a total of 2240 minutes until the frequency reached 4.3 MHz.

  The present invention is not limited to the above examples, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

  For example, in the above example, two slits 12a are provided in the 180 ° direction, but four slits 12a may be provided on the cross. Moreover, you may provide only one.

  The magnet 13 installed in parallel with the slit 12a may be a permanent magnet or an electromagnet as long as it can form a necessary magnetic field. The material may be any of ferrite, samarium cobalt, neodymium and the like.

  Moreover, in the said example, although the electron beam vapor deposition apparatus which applies the film thickness sensor apparatus 11 of this invention showed what supplies the substrate film 2 continuously using a roll, it conveys a board | substrate one by one. Things can be used. Further, a thin film may be formed on a stationary substrate. Furthermore, a magnet 9 disposed between the film forming range of the cooling roll 3d and the electron gun 5, the crucible 6, and the magnet 8 may be installed as necessary.

2 substrate film 5 electron gun 6 crucible 7 material 10 film thickness sensor device 11 film thickness sensor 12 rotating body 12a slit 13 magnet

Claims (2)

A quartz-vibration film thickness sensor device that obtains the thickness of the thin film when the thin film is formed by attaching a material evaporated and heated by accelerating electrons to the substrate surface,
An electron beam evaporation apparatus comprising: a rotating body having a slit disposed between the film thickness sensor and the material; and a magnetic field generating means for generating a magnetic field in a direction intersecting a longitudinal direction of the slit. Film thickness sensor device.   2. The film thickness sensor device for an electron beam evaporation apparatus according to claim 1, wherein a width of the slit is narrower than a width of the film thickness sensor.

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