JP2830478B2 - Vacuum deposition equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum deposition apparatus for producing a thin film, and more particularly to a vacuum deposition apparatus suitable for producing a ferromagnetic metal thin film medium suitable for high density magnetic recording.

[0002]

2. Description of the Related Art In recent years, the recording density of magnetic recording media has been significantly improved. Among these media, a ferromagnetic metal thin film type medium is considered most promising. When this ferromagnetic metal thin film is manufactured by vacuum evaporation, an oblique evaporation method described in U.S. Pat. Nos. 3,342,632 and 3,342,633, and the like, and Japanese Patent No. 3,342,633. When the vapor deposition method in an oxygen atmosphere described in US Pat.
It has been found that a magnetic thin film having good characteristics can be obtained.

On the other hand, in the field of digital signal recording and high-definition TV signal recording, the demand for further higher recording density has been increasing in conjunction with the trend of lightness, thinness and small size. Further improvement in magnetic properties is required.

[0004]

In order to increase the recording density, it is required for the medium to increase the magnetic properties, particularly the coercive force and the residual magnetic flux density. As a conventional technique for achieving a high coercive force, first, an incident angle of oblique deposition is increased. However, when the incident angle is increased, evaporation atoms available for vapor deposition are reduced, so that vapor deposition efficiency is reduced, and mass productivity and cost performance are significantly impaired. Next, the coercive force can also be increased by increasing the amount of oxygen introduced, but at this time, the residual magnetic flux density decreases, and as a result, the energy product can be improved up to a certain area, but eventually reaches a plateau Shows a tendency to become

The present invention has been made in view of the above problems, and provides a vacuum evaporation apparatus having good magnetic properties and high evaporation efficiency.

[0006]

In order to achieve the above-mentioned object, a vacuum evaporation apparatus according to the present invention is provided with a shield plate for oblique evaporation, and an electric space is provided in a space behind the shield plate (between the cooling can and the shield plate). And a porous nozzle for introducing gas made of a material which is insulated from the surroundings and to which a voltage can be applied.

[0007]

[Function] The magnetic properties of a thin film strongly depend on its internal structure.
In order to obtain excellent characteristics, the microcrystals must be small, have the same grain size and crystal orientation, and must be magnetically separated (micromagnetization).
Is a necessary condition.

According to the present invention, when the ferromagnetic metal atoms adhere to the film-like substrate, the gas molecules ejected from the gas nozzle are excited, dissociated, or ionized and supplied in a state of retaining high energy. Will be. The introduction of an active high-energy gas has the effect of promoting the above-mentioned micro-magnetization efficiently with a small amount of gas due to its high reactivity, thus improving magnetic flux density and coercive force and improving magnetic properties. Is done.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are a basic configuration diagram of a vacuum evaporation apparatus used in an embodiment of the present invention and an explanatory view of a nozzle, respectively.

[0010] In FIG.
Polymer film 4 to be transported along the cooling can 2
It is fed and wound up on the take-up roll 3. Cooling
A hearth or evaporating material 5 is stored below the can 2
The evaporation source 6 composed of a crucible is further positioned between the two.
There is a shielding plate 7 for oblique deposition and a gas introduction
Porous nozzles 8 are arranged.
The whole element is 10^-3-10 ^-6Operates in a torr vacuum atmosphere
I do.

In the vacuum deposition, first, a 5 to 20 μm polymer film 4 (mainly made of polyethylene terephthalate) wound on an unwinding roll 1 is supplied. After the vapor of the evaporation material 5 made of a ferromagnetic metal such as Co, Ni, or Fe is received from the evaporation source 6 located below, the magnetic layer is formed, and then the winding is completed by the winding roll 3. The shielding plate 7 defines the minimum steam incident angle θmin and is set in consideration of necessary magnetic characteristics (particularly coercive force), but it is desirable to make θmin as small as possible. Since the shielding plate 7 plays such an important role of positioning, it is cooled so as not to be thermally deformed. Shield plate 7
Before the evaporation, when the evaporated atoms adhere to the polymer film 4, a reactive gas such as O ₂ , NH ₃ , N ₂ , H ₂ O is supplied to the nozzle 8.
From the direction of the adhesion area. At this time, not only the gas is simply blown out, but also, as shown in FIG. (DC, commercial AC, and high frequency are all applicable), discharge, and blow a reactive gas. The discharge depends on the nozzle shape and surrounding conditions, but the voltage is 200 to 800 V and the current is 50
A glow discharge region of about 300 mA is stable. When the amount of the reactive gas introduced is small, the discharge tends to be unstable. However, stabilization can be achieved by high-frequency discharge or mixing with an inert gas (eg, Ar).

Further, it is better to provide the nozzle 8 with a plurality of small-diameter air outlets from the viewpoints of uniformity of gas radiation distribution and discharge stability.

Next, typical experimental examples and their results will be described. The main conditions of the experiment are listed as follows: (1) Co was evaporating material, (2) minimum vapor incident angle θmin = 30 °,
(3) The introduced gas is O ₂ , the introduced amounts are 0.1, 0.2, 0.3, 0.4 l / min in the order of a, b, c, d. Discharge current is 50-100
mA discharge, (5) substrate is a 10 μm thick polyethylene terephthalate film, (6) film running speed is 20 m / min, (7) ferromagnetic metal thin film has a thickness of 0.2
μm. As a comparative example, a sample obtained by gas introduction in a conventional apparatus was also prepared.

The measurement of the magnetic properties is performed by using a vibrating sample magnetometer (VS).
M), and the measurement of the film thickness of the thin film necessary for obtaining the magnetic flux density was performed with a scanning electron microscope (SEM).

FIG. 3 summarizes these results.
The symbols in the symbols indicate the data of the comparative examples, the symbols in the symbols ◎ indicate the data of the samples obtained by the apparatus of the present invention, and the oxygen introduction amounts correspond to the same symbols. As is clear from this figure, it is understood that the magnetic characteristics are improved according to the apparatus of the present invention even at the same minimum steam incident angle.

Although the oblique deposition has been described in detail above, when applied to the production of a Co—O perpendicular magnetic film, the perpendicular coercive force is from 1,000 (Oe) to 2,
2,000 (Oe) in the range of 1.2 to
It was also confirmed that a film having a 1.7 times higher saturation magnetic flux density could be obtained.

[0017]

As described above, according to the vacuum vapor deposition apparatus of the present invention, the opposite gas is increased in energy by discharge excitation and effectively used, so that the magnetic characteristics are improved even in the incident angle region where the vapor deposition efficiency is high. An excellent practical effect that it can be obtained.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a main part of an embodiment of a vacuum deposition apparatus of the present invention.

FIG. 2 is a perspective view of a nozzle portion of the apparatus.

FIG. 3 is a magnetic characteristic diagram showing the effect of the magnetic recording medium obtained by the apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 4 polymer film (film-like substrate) 5 evaporation material 6 evaporation source 7 shielding plate 8 porous nozzle

Claims (2)

(57) [Claims] An apparatus for producing a thin film by depositing metal vapor generated from an evaporation source on a film-like substrate, comprising: a shielding plate for limiting an incident angle; A vacuum vapor deposition apparatus comprising a porous nozzle for introducing a gas which is insulated from the surroundings so that a voltage can be applied. 2. The vacuum evaporation apparatus according to claim 1, wherein the direction of gas blowing from the nozzle is directed to a region where the evaporated metal from the evaporation source is attached.