JPH02236273A - Electron beam vapor deposition method and electron beam vapor deposition device - Google Patents

Abstract

PURPOSE:To form a thin film having uniform properties on a high-polymer film by placing a long evaporating source intersecting orthogonally with the moving direction of the high-polymer film and heating the evaporating source to evaporate by irradiation of the source with a non-scanning electron beam at the time of forming the thin film on the surface of the moving high-polymer film by electron beam vapor deposition. CONSTITUTION:The high-polymer film 1 is wound around a cylindrical rotary support 7 in a vacuum vessel 11 and the film 1 is moved by the rotation thereof. The evaporating source 2 past the center by(d) in the direction of a wire-shaped cathode 4 from the center O of this rotary support 7 is disposed in the shape long in the transverse direction of the high-polymer film 1. A raw material 3, such as Co-Ni alloy, to be deposited by evaporation therein is heated by the broad electron beam 6 from the cathode 4 and the vapor deposited film of the Co-Ni alloy is formed on the high- polymer film 1 without scanning the electron beam 6. The uniformly thin film of the Co-Ni alloy is otherwise deposited by evaporation at a high speed on the high- polymer fill by providing a relation Fx)Fy between the scanning frequency Fx of the electron beam 6 in the transverse direction of the high-polymer film and the scanning frequency Fy in the moving direction of the film.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electron beam evaporation method and an electron beam evaporation apparatus.

BACKGROUND OF THE INVENTION The technology of continuously forming thin films on polymer films continues to be developed in the fields of magnetic tapes, capacitors, and the like. As is well known, thin film formation techniques include sputtering, electron beam evaporation, ion plating, chemical vapor deposition, etc., but evaporation tape and perpendicular magnetic Electron beam evaporation is attracting attention as a method suitable for producing tapes [JP-A-57-71515, JP-A-57-19
No. 493, JP-A-6J-741-42] In electron beam evaporation, an evaporation source container containing an evaporation material is placed in a refractory container such as a rod ρ, Al2O3, etc., facing a rotating support, and a pierce-type evaporation source container is placed. The electron beam emitted from the electron gun is 20KV~
Generally, vapor deposition is carried out under conditions such that the film is accelerated to rs o KV and scanned at about 5 to 100 Hz in the direction perpendicular to the direction of movement of the polymer film so that the film is uniform in the width direction. In addition, improvements have been made to enable electron optical systems to be realized in the high-power region by focusing the electron beam.

Problems to be Solved by the Invention However, with the above configuration, the performance of the magnetic tape cannot be ensured when the speed is increased, and the performance also deteriorates when an optically anisotropic film is obtained by oblique deposition. There were some issues and improvements were desired. The present invention has been made in view of the above-mentioned circumstances, and provides an electron beam evaporation method suitable for obtaining a uniform obliquely evaporated film.

Means for Solving the Problems In order to solve the above-mentioned problems, the electron beam evaporation method of the present invention includes an evaporation source extending in a direction perpendicular to the direction of movement of a moving polymer film by non-scanning electron beam heating. This is what I did.

Function: The electron beam evaporation method of the present invention has the above-described configuration, and oblique evaporation is performed on a moving polymer film at a constant incident angle using a vapor flow emitted from an electron beam evaporation source that does not change over time. Therefore, uniform physical properties can be obtained. Moreover, even if the film is moved at high speed without being limited to oblique vapor deposition, a uniform film thickness distribution can be obtained, and vapor deposition for other purposes can also be improved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Example 1] FIG. 1 is a diagram showing the main parts of an electron beam evaporation apparatus used to carry out the present invention. In Fig. 1, 1 is a polymer film such as polyethylene terephthalate or polyimide, and 2 is an evaporation source container with a ram length extending in a direction perpendicular to the moving direction of the polymer film.
It is made of refractory materials such as ZrO2, MgO, etc., and 3 is made of Co, Co-Ni, Co-Cu, Co-
Vapor deposition materials such as Cr, Fe-Ni, Si, Or, etc. 4 is a beam that can irradiate a wide range of electron beams without scanning, unlike the conventional pierce-type electron gun that generates electron beams focused on a small spot. 6 is a reflective focusing electrode. Reference numeral 6 denotes an electron beam, which is non-scanning and is deflected in this case by a deflection magnetic field (not shown) so as to be deflected toward the evaporation material, thereby heating the evaporation material and making it possible to perform evaporation. Reference numeral 7 denotes a rotating support body, which is often a cylindrical can and preferably has a configuration that allows heating and cooling. 8 is a polymer film unwinding shaft, and 9 is a winding shaft. 10 is a mask used to limit the range of the incident angle, 11 is a vacuum chamber, and 12 is a vacuum evacuation system.

The present invention will be explained in comparison with a conventional method of using the apparatus shown in FIG. 1 in which a button-shaped canard is used instead of a linear cathode to scan and irradiate a horizontally elongated evaporation source.

In Figure 1, a cylindrical can with a diameter of 1 m is used, and
6 (ml), position the center of the evaporation source container directly below the center of the can, towards the linear cand side, and increase the internal volume to 7 (ml).
Co-Ni in the Mgo container of fX80ffX8ffi
(Co: 80 wt%) and a film thickness of 100 μm CO-Ni was deposited at 5×10-5 (Torr).
~ I The polymer film used was polyethylene terephthalate with a thickness of 10 μm, which had an undercoat layer in which StO 2 fine particles of 100 particles in diameter were arranged in advance at 20 particles/(μm). The width of the film is 60 cIR and the length is 5000 m. Co-Ni-0 was evaporated under each electron beam condition.
After forming the film, stearic acid was applied at 0.6 [■/co], a 0.4 μm pack coat layer was placed on the film, and an 8 mm wide tape was processed. To check the uniformity of magnetic tape, an 8 mm video camera was modified and recorded at 5 (MHz), 10 (
MHz) and in LP mode. The main manufacturing conditions and characteristics are summarized in Table 1. Note that the energy of the electron beam is constant at 30 keV, and since it is difficult to measure the diameter of the heel, the width of the portion with high brightness as seen visually in the direction of movement is defined as its dimension. In addition, the length of the beam irradiation area in the direction perpendicular to the film movement direction was set to 69α in order to maintain a uniform film thickness with a width of 501 mm.

Table 1> As is clear from the above results, according to the present invention,
The advantage is that the evaporation rate obtained per input power is high. This is because as the electron beam becomes larger in current, electrons repel each other, making it difficult to focus.
The main reason is thought to be that the above-mentioned phenomenon is less likely to occur in the non-scanning type, whereas the spot diameter becomes larger. or,
The difference in characteristics is that, in addition to the fact that the incorporation of impurities can be effectively reduced by increasing the speed, the present invention uses steady and constant evaporation at an incident angle, and the fact that the horizontally elongated Although an evaporation source is obtained, the spot moves over a short period of time, resulting in microscopic non-uniformity.The difference with the conventional method is larger than expected, and the difference can be seen in increased noise. ing.

The above example is about magnetic tape manufacturing, but S10
A similar effect can be obtained by forming the obliquely deposited film in step 2. In this case, the present invention has a unique effect such that the dispersion of optical anisotropy can be reduced. If only high-speed vapor deposition is effective, any vapor deposition can take advantage of the advantage that it can be achieved with less input power.

[Embodiment 2] This embodiment aims to provide an electron beam evaporation method with another configuration that allows electron beam evaporation to be performed at high speed and to obtain favorable characteristics in terms of physical properties. Electron beam evaporation was carried out based on the apparatus shown in FIG. 1 used in Example 1, with some of the structural requirements of this example added. In the present invention, a conventionally used Pierce-type electron gun is used to scan a highly focused electron beam in two axes, and FIG. 2 shows an explanatory diagram of the scanning direction.

In Figure 2, 1 is a moving polymer film, with the moving direction being Y.
The direction perpendicular to the axis is the X-axis. 2 is an evaporation source container, and 3 is a vapor deposition material.

The electron beam is focused and 101111
A spot diameter of ~3011 is desirable, and should be optimized in relation to the scanning conditions described later.

The scanning conditions necessary to ensure uniform physical properties at high speed on a moving polymer film are such that the scanning frequency Fx in the X direction satisfies the relationship Fx)6Fyy between the scanning frequency Fx in the Y direction and the frequency F in the Y direction. preferable. Fx is 30 Hz or more and up to 1 KHz, and it is necessary to configure a coil such that the scanning magnetic field follows the above frequency. Designing such a coil is not necessarily easy, so it is difficult to design such a coil in practice. is 1 00
A preferred value is Hz to 5ooHz. Fy can be optimized in relation to Fx, but when applying to oblique deposition, the scanning distance in the Y direction is also important depending on the desired physical property values (e.g. coercive force and coercive force dispersion of the magnetic film). It is.

A rule of thumb for this is the length Z on the film to be deposited.
~%it is conceivable that. For example, when manufacturing magnetic tape%
As the size increases, the sensitivity may become insufficient in the high frequency range due to coercive force dispersion.If it is below average, the best efficiency can be achieved with the input power and the deposition speed obtained for high-speed deposition. This is because power loss becomes noticeable.

Examples of the present invention will now be described in more detail in comparison with comparative examples. The apparatus shown in Figure 1 is equipped with a 30KV, 250KW electron gun (EH250/30) made by Ardenne, with the irradiation angle of the electron beam being 4 degrees with respect to the normal to the surface of the evaporation material. However, vapor deposition was performed using the same geometry as in Example 1 except for the scanning distances in the Fx, Fy, and Y directions as parameters. The length of the film to be deposited is 380 fl. Table 2 summarizes the main parameters, the deposition rate obtained, and the C/N when made into a magnetic tape.

Table 2 As is clear from Table 2, by setting Fx larger than Fy, evaporation can be performed in a situation equivalent to a linear evaporation source (extending in the X direction) moving back and forth in the Y direction. This makes it possible to reduce the deterioration of the characteristics and increase the input power for scanning in the Y direction, thereby making it possible to obtain high-speed conditions.

[Embodiment 3] This embodiment aims to provide an electron beam evaporation method in which an emphasis is placed on improving the characteristics of electron beam evaporation by scanning also in the Y direction as described in Embodiment 2.

This is particularly effective in oblique evaporation when aiming to further improve physical properties, and allows electron beam evaporation to be performed in a state where the incident angle can be regarded as constant.

One possible method for this purpose is to increase the electron beam spot diameter (conventionally, the focus has been mainly on the area where the electron beam can be focused best) and to decrease the scanning distance for scanning with Fy. In this case too, F! Basically, Fy is preferably 5 times or more.

Another method is to reduce the deposition rate and film movement speed so that the incident angle can be equivalently considered to be constant.
It is conceivable to increase both Fx and Fy.

Examples of the present invention will be described in more detail below in comparison with comparative examples. Table 3 shows the main parameters and the results of comparing the C/N of an 8 mm tape produced as a prototype in the same manner as in Example 1.

Table 3 As is clear from Table 3, in contrast to the conventional system in which the power contributing to evaporation does not increase proportionally to the input power, in the present invention, the increase in speed is proportional to the increase in input power compared to the conventional system. Since the C/N is larger and has a better C/N as a magnetic tape, the magnetic tape manufactured according to the present invention has the effect of making the incident angle equivalently uniform, and the input power Compared to conventional methods in which the evaporation source becomes unstable due to the interaction between the evaporated atoms and the irradiated electrons even if the power density is forcibly increased, the present invention is characterized in that the speed can be sufficiently increased while the power density is within an appropriate range. It turns out that there is.

[Embodiment 4] The method described in Embodiment 3 is further advanced to provide a vapor deposition apparatus that is used to increase input power, achieve higher speed, and secure characteristics.

This device is an electron beam evaporation device in which a mask that determines the minimum angle of incidence is varied in accordance with the deflection and scanning conditions of the electron beam, so that the angle of incidence remains constant.

FIG. 3 is an explanatory diagram of main parts of a vapor deposition apparatus according to an embodiment of the present invention. In FIG. 3, reference numeral 13 indicates a part of an arc on the circumferential side of the cylindrical can, and the polymer film is deposited while moving along this surface. 14 is an evaporation source container, 15 is an evaporation material, 16 is a variable mask, and 17 is a 30 KeV electron beam. This electron beam is deflected only in the Y direction at a constant frequency, and the conditions are optimized by changing the deflection frequency Fy (Hz) so that the film thickness is uniform according to the moving speed of the film. There is a need. Fx in the X direction
=0 non-scanning electron beam (X direction beam width 69cm)
17 is at position b, the mask position that determines the minimum incident angle θ is located at B, and when it is at position b, the mask 16 is at position A.

This specific configuration may be a mechanism of reciprocating motion, but in the case of high speed, it is better to use rotation, and in the case of rotation, the mask shape needs to be modified from a circular shape. In addition, it is natural that the incident angle will change if a large amount is deposited on this mask, and by connecting an IJ uniforming mechanism or combining methods such as gas blowing, it is possible to deposit onto a long polymer film. It is necessary to do so.

This will be explained below using a specific example. In Figure 1, the diameter of the cylindrical can is 1 m, the evaporation source container is 70σ downward from the center of the cylindrical can, d is 25crII in Figure 1, a,
b was set to 5 with central vibration. Note that a and b are intervals assuming the center of the electron beam.

The mask 16 has a mechanism that moves back and forth in a straight line between 2 and 3 crn from the can surface. The movement of AB is IJ near, and a and b are also scanned by the magnetic field generated by passing a triangular wave through the coil, and IJ near, and θ cannot be strictly constant, but approximately. This is a range that can be considered constant. The frequency of AB round trip and AB round trip was set to be the same. AB so that the minimum angle of incidence is approximately 40 degrees
was set at 4.3 mouths. Incidentally, the oxygen nozzle was fixed at No. 16 so that the vapor was not deposited on the tip of the mask.

Co, Ni (Co 80w+%) was added at 0.1,
czm, oxygen partial pressure sx1o-5 (Torr).

Table 4 shows the results of comparing the C/N under other main conditions and using the obtained magnetic film as an 8 mm tape.

Table 4 As mentioned above, it is possible to effectively increase the amount of evaporation by scanning in the Y direction to prevent the power density from becoming too large while increasing the input power, and to keep the incident angle constant. By using this method, even if the deposition rate is increased, the characteristics do not deteriorate, but are slightly improved, and the fact that the effect is more visible at shorter wavelengths is in line with future trends in magnetic recording. It can be evaluated.

[Embodiment 5] Another means for achieving mass evaporation using a non-scanning electron beam in the width direction using a linear filament will be described below. FIG. 4 is a diagram showing the main part of an electron beam evaporation apparatus according to another embodiment of the present invention. In FIG. 4, the same components as in FIG. 1 are given the same numbers.

In FIG. 4, numeral 18 denotes a linear filament made of Mo, W, etc., and whether to use one or more filaments may be selected as appropriate depending on the required current density. Reference numeral 19 denotes a reflective electrode for limiting the incident angle and focusing the electron beam at the same time, and is preferably set to the same potential as 18 or slightly negative. Since the linear filament is at a high temperature, it reevaporates and Co −
Although Ni and the like are not deposited, the shape of the reflective electrode changes, which has a serious effect on the focusing of the electron beam. Therefore, it is preferable to construct it as a belt-like electrode with a cleaning mechanism. The closer the linear filament is to the evaporation source, the less the current density will decrease due to the divergence of the electron beam.
Favorable for large view evaporation. In Fig. 4, the filament is provided on the mask side, but it could also be placed on the opposite side of the mask with respect to the center of the evaporation source, but this would require a separate reflective electrode, which would complicate the electro-optical design. This is a difficult point.

A specific example will be described below.

In Figure 4, the center of a 1m can is set as 0, the center P of the evaporation source is placed 70cm below the can, and 25cn1 in the Y direction, and two tungsten filaments of φ1 are placed on the ○P line at P:Z=14crn. However, the reflective electrode has ZR=1.3c
It is a curved surface with a curvature of 12 crn and a circumference of 1.
It was placed under the condition of 2crn. The voltage was 30 KV, and the reflective electrode was 30.2 KV. For comparison, a tape was formed by vapor deposition under the same conditions as in Example 1, and the characteristics were compared.

With an input power of 120 KW, the beam width was set to 1.2 m, so the film movement speed could be increased to 280 m/mm for the same film thickness, and the C/N characteristics were also improved to es ( +1.9 (dB) at 10 (MHz)
+2. s(dE), which was good. Input power to 25
At 0 KW, the beam width is 2.2 cm, the film moving speed can be increased to 430 m/m, and the C/N characteristics are +2.3 (dB) at 5 (MHz) and 10 (MHz).
) was good at +3.7 (dB).

[Embodiment 6] Another means for realizing high-speed deposition in forming a perpendicularly magnetized film by mass evaporation using electron radiation from a linear filament will be described. FIG. 5 shows an electron beam evaporation apparatus according to another embodiment of the present invention.

In FIG. 6, parts that may have the same configuration as in FIG. 1 are given the same numbers. In Figure 5, 20 is almost directly above the evaporation source (
Whether a single filament or a plurality of linear filaments of Mo, W, etc. are arranged in the filament (not necessarily limited) depends on the design of the total power.

21 is a rotating support consisting of an endless belt made of magnetic foil such as titanium foil, stainless steel foil with iron foil on the inside, or magnetic foil such as iron or iron/nickel alloy foil, and the magnetic field is applied to the side of the cylinder. A plurality of cylinders 22 made of a composite body of magnets are arranged so as to form a curved surface, and the cylinders 22 are driven to rotate the belt. 23
is an auxiliary nip roller, which is effective when the magnetic field (22) cannot be made too strong to maintain a constant circumferential speed.

The electric field formed by 21 is important for effectively focusing the electrons emitted from 20, and 24 is an electrode that also functions as a mask. Optimization of the electric field created by 21 and 24 can be done empirically to some extent in relation to the position of 2o, but it may also be determined and finely adjusted by computer simulation.

26 is a free roller.

A somewhat complicated aspect of this device is that the take-up system is placed at the same high voltage as the rotating belt, but the option is to place the take-up system, belt, etc. at ground potential, and place the evaporation source container at opposite polarity. It is also possible to use a high voltage.

The device of the present invention has the above-described configuration, and the following points are emphasized in its effectiveness in forming a perpendicularly magnetized film.

(1) The film is heated by the radiant heat of the linear filament, and since the radiation source is not only a conventional evaporation source but also located close to the film, the properties of the film are improved by forming the film at high temperatures.

(2) A compromise between the shape of the endless belt, which allows the vapor to be deposited as nearly vertically as possible, and the condition where the electrons emitted by the linear filament are best focused at the evaporation source. A perpendicularly magnetized film with high speed and good performance can be obtained by designing the perpendicularly magnetized film at high speed.

In addition, not only perpendicular magnetization films but also high melting point materials can be deposited at high speed and the deposition efficiency can be increased, which are common effects obtained.

Hereinafter, a comparison will be made between a case where a perpendicularly magnetized film is formed using the apparatus of the present invention and an example where a perpendicularly magnetized film is deposited using a conventionally known cylindrical can.

The shape of the endless belt (iron, 0.2 mt) is approximated to have a radius of curvature of 22 holes, and the cylindrical magnet with an ecrn diameter is combined with an alnico magnet, and the surface magnetic field is 5oO (
12 were arranged, and the vapor deposition range (θ in FIG. 5) was set to 46 degrees. The tungsten filament is a linear one with a diameter of 1 m, and 2 cr from the endless belt.
placed under n. Using this device, a polyimide film with a thickness of 8 μm was used, and the endless belt was placed in close contact with static electricity, and 69 crn was irradiated in the width direction in a non-scanning state at voltages of 3 o KV and 50 KV, and Co-Cr (
Co: 80 wt%) was deposited to a thickness of 0.2 μm.

Stearic acid was applied as a lubricant at 0.4 μ/m", and
Using a millimeter tape, a wavelength of 0.3 μm was recorded using a Sendust head with a gap length of 0.1 μm, and the C/N was compared.

The reference for comparison is Co-Cr formed by the conventional method.
g, cylindrical can with a diameter of 60 mouths (can temperature 220℃)
An evaporation source is placed 25m directly below, and a 30KV electron beam is
It is deposited by scanning along the axis and within a range where the incident angle is within 16 degrees.

The comparative example is 30KV, 150 (beam width 2cm 6 9
mX 3. (scanned to am) Film was formed at KW at 125 m/-. The main conditions and characteristics are summarized in Table 5.

Table 5 In addition to the above, it can be easily inferred from the examples described above that the present invention can further improve efficiency by scanning in the film movement direction (Y-axis).

As seen from Table 5, according to the present invention, the deposition rate is also high;
It can also be seen that the properties of the perpendicularly magnetized film obtained are also good.

Effects of the Invention As described above, according to the present invention, by heating the evaporation source using a non-scanning focused beam in the direction perpendicular to the direction of film movement, thin films can be formed at high speed with improved target physical properties. It has excellent effects such as being able to.

[Brief explanation of drawings]

Figure 1 is a side view of the vapor deposition apparatus used to implement the present invention, Figure 2
The figure is an explanatory diagram of the relationship between the evaporation source and the moving direction of the film.
The figure is a side view of essential parts of the vapor deposition apparatus of the present invention, and FIGS. 4 and 5 are both side views of the vapor deposition apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Polymer film, 2... Evaporation source container, 3... Evaporation material, 4... Linear cathode, 6... Reflection electrode, θ... Accelerated electron beam (non-scanning in the X direction), 7... Cylindrical can, 10... Mask, 15... Vapor deposition material, 16 ...Variable mask, 18... Linear filament, 19... Reflective electrode (also mask), 2o... Linear filament, 21...
... Rotating support body, 22 ... Cylindrical magnet assembly,
24... Focusing electrode (cum mask). Lr)g

Claims (6)

[Claims] (1) Electron beam evaporation characterized in that when forming a thin film on a moving polymer film by electron beam evaporation, an evaporation source extending in a direction perpendicular to the moving direction is configured by non-scanning electron beam heating. Law. (2) The frequency of scanning in the moving direction of the polymer film is F
An electron beam evaporation method characterized in that an electron beam evaporation source is used, where F_x is greater than 5F_y, where F_x is a scanning frequency in a direction perpendicular to the direction of movement. (3) An electron beam evaporation method characterized in that during oblique evaporation, evaporation is performed using an electron beam evaporation source scanned in the direction of movement and in the direction orthogonal to the direction of movement so that the incident angle is constant. (4) An electron beam evaporation device characterized by changing a mask that determines the minimum incident angle in accordance with the scanning frequency in the direction of movement of the polymer film. (5) An electron beam evaporation apparatus characterized in that a linear filament is disposed above an evaporation source container disposed facing a rotating support. (6) An electron beam evaporation apparatus characterized in that the rotating support body is composed of a belt-like rotating body and also serves as a reflective electrode for a linear filament.