JP2635385B2 - Ion plating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is effective in efficiently forming a high-quality thin film uniformly over a large area using plasma generated from a composite cathode plasma gun. The present invention relates to a simple ion plating method.

[Prior Art] Conventionally, vacuum deposition has been widely used for optical thin films, decorative purposes, and the like. Further, a technique called ion plating for improving a film quality by introducing a hollow cathode and high-frequency excitation into vacuum deposition to generate glow discharge is also known.
However, there has been a problem in efficiently depositing a high-quality film on a large-area substrate such as a window glass of an architectural building or a glass for an automobile by using these methods. For example, in the hollow cathode method, since the cathode portion is exposed to plasma,
Stable continuous vapor deposition was difficult due to melting or deformation. In addition, there is a possibility that ions may flow back to the cathode side, and there is a problem in performing high-power discharge for a long time. In the high-frequency method, it is necessary to use a ring-shaped antenna or the like to generate a discharge, and to arrange a metal plate or the like on the substrate side to apply a bias, making it difficult to create a uniform discharge area over a large area. In addition, since the discharge is affected by the gas pressure in the vacuum chamber, the discharge is unstable, and it has been difficult to uniformly and continuously perform stable vapor deposition at a high speed on a large-area plate.

[Problems to be Solved by the Invention] As described above, it is extremely difficult to form a uniform thin film having a large area with a conventional hollow cathode or an ion plating method using high-frequency excitation. Was.

[Means for Solving the Problems] The present invention has been made for the purpose of solving the above-mentioned drawbacks, and is to deform an arc discharge plasma flow generated by arc discharge into a sheet by applying a magnetic field, A permanent magnet that is elongated in the width direction of the sheet-like plasma is placed under the evaporation material hearth placed below the sheet-like plasma, and the sheet-like plasma is bent by the magnetic field of the permanent magnet to guide the evaporation material, By moving the evaporation material hearth and the permanent magnet thereunder relative to each other, the evaporation material hearth is guided on the evaporation material hearth, and the moving direction is parallel to the base and perpendicular to the width direction of the sheet-like plasma. The evaporation source is evaporated by moving the evaporation source hearth and the permanent magnet below the hearth relative to each other so as to be in the same direction. An ion plating method characterized by forming a coating on a substrate placed in, and an arc discharge plasma flow generated by arc discharge is deformed into a sheet by applying a magnetic field,
A permanent magnet elongated in the width direction of the sheet-like plasma is placed under the evaporation material hearth placed below the sheet-like plasma, and the sheet-like plasma is bent by the magnetic field generated by the permanent magnet and guided onto the evaporation-material hearth. At the same time, the evaporation raw material hearth and the permanent magnet thereunder are translated so that the moving direction is parallel to the base and perpendicular to the width direction of the sheet-like plasma, so that the evaporation raw material is removed. Evaporating, evaporating the evaporating raw material,
It is an object of the present invention to provide an ion plating method comprising forming a film on a substrate placed above the evaporation raw material.

 Hereinafter, the present invention will be described in detail.

FIG. 1 is a schematic diagram showing a basic configuration of an example of an apparatus used for performing ion plating by the method of the present invention. FIG. 1 shows an example in which a substrate on which a film is formed is fixed.

 FIG. 2 is a cross-sectional view of an area shown in FIG.

In the present invention, a plasma flow by arc discharge is used. Such an arc discharge plasma flow is generated by applying a plasma generation DC power supply 4 between the arc discharge plasma flow source 1 and the anode (hearth) 2 to perform arc discharge.

As such an arc discharge plasma flow generation source 1, a composite cathode type plasma generation device, a pressure gradient type plasma generation device, or a plasma generation device combining the both is preferable. Such a plasma generator is described in Vacuum Vol. 25, No. 10, issued in 1982.

The composite cathode type plasma generating apparatus has a small auxiliary cathode heat capacity and a main cathode made of LaB _6, to concentrate initial discharge to the auxiliary cathode, by using it to heat the main cathode LaB _6, This is a plasma generator in which a main cathode LaB ₆ performs an arc discharge as a final cathode. For example, there is an apparatus as shown in FIG. Examples of the auxiliary cathode include coils or pipes of a high melting point metal such as W, Ta, and Mo.

In such a composite cathode type plasma generator,
A small auxiliary cathode 52 of the heat capacity and heated at intensive initial discharge, is operated as an initial cathode, the main cathode 51 indirectly LaB ₆
Heating the so eventually is in a manner to be shifted to the arc discharge by the main cathode 51 of LaB _6, the main cathode 51 of LaB ₆ before the auxiliary cathode 52 affects the service life at a high temperature above 2500 ° C.
Is heated to 1500 ° C. to 1800 ° C., a large electron current can be emitted, and a further increase in the temperature of the auxiliary cathode 52 is avoided.

A pressure-gradient plasma generator is a device in which an intermediate electrode is interposed between a cathode and an anode, and discharges while maintaining the cathode region at about 1 Torr and the anode region at about 10 ^-3 Torr. There is no damage to the cathode due to backflow of ions from the region, and the gas efficiency of the carrier gas for creating the discharge electron flow is dramatically higher than that of the discharge type without the intermediate electrode, enabling large current discharge. Has the advantage that

The composite cathode type plasma generator and the pressure gradient type plasma generator each have the above-mentioned advantages, and a plasma generator combining both of them, that is, a composite cathode is used as a cathode and an intermediate electrode is also provided. The plasma generating apparatus described above is very preferable as the arc discharge plasma flow source 1 of the present invention because the above-mentioned advantages can be obtained at the same time.

FIG. 1 shows an arc discharge plasma source 1
An example is shown in which a composite cathode 21 as shown in the figure, a first intermediate electrode 22 including an annular permanent magnet, and a second intermediate electrode 23 including a second intermediate electrode including an air core coil are used.

In the present invention, the anode (hearth) 2 is disposed so as to be located below the plasma generation source 1, and the air-core coil 6
As a result, a high-density plasma flow generated by the arc discharge generated from the plasma generation source 1 is drawn into the vacuum chamber 3. further,
In order to make the drawn plasma into a sheet shape, the pair of permanent magnets 5 are sandwiched between the hearth 2 and the base 7 with the N pole faces facing each other, and the N pole of the permanent magnet or
The S pole face is two hearths or the substrate 7 on which a coating is formed
The sheet plasma 8 is formed by pressing the plasma in a direction parallel to the hearth 2 or the substrate 7.

In FIG. 1, the sheet plasma 8 deformed into a sheet shape by a pair of permanent magnets 5 has a thickness from the top to the bottom in FIG. 1 and a direction perpendicular to FIG. 1 as shown in FIG. It has a width.

The sheet plasma 8 is bent at about 90 ° by the magnetic field generated by the permanent magnet 9 placed under the hearth 2, focuses on the hearth 2, evaporates the raw material 10 in the hearth 2, and evaporates the particles. Is formed on the substrate 7 placed above the substrate.

In the present invention, as shown in FIG. 2, the permanent magnet 9 preferably has at least the same length as the hearth 2 in the width direction of the sheet plasma 8. This is because the sheet plasma 8 is evenly incident on the evaporation material in the hearth 2, and the evaporation material can be used effectively.

In the present invention, the permanent stone arrangement 9 and the hearth 2 are:
As shown in FIG. 2, the sheet plasma 8 preferably has at least the same length as the base 7 in the width direction. The reason is that the evaporation raw material evaporated from the hearth 2 can be evenly and uniformly attached to the base 7 in the width direction of the sheet plasma.

In the present invention, the hearth 2 and the permanent magnet 9 are
In the direction of arrow A in the figure, that is, in the direction perpendicular to the width of the sheet plasma when the translational motion is performed in a plane parallel to the base 7,
The evaporation material evaporated from the hearth 2 is uniformly adhered to the base 7, and the film thickness can be prevented as much as possible from the portion just above the hearth 2 of the base 7 and the portion apart from the hearth 2. Very good.

In the present invention, the evaporating material hearth and the permanent magnet thereunder are relatively moved so that the moving direction is parallel to the substrate and perpendicular to the width direction of the sheet-like plasma. For example, as shown in FIG. 5,
Using a permanent magnet 9 thinner than the hearth 2, the permanent magnet 9 is moved relative to the hearth 2 as shown by an arrow B in FIG. By doing so, the use efficiency of the evaporation raw material is increased.
This is particularly effective when the evaporation source is an expensive material such as a metal oxide. This operation can be performed in combination with the translational movement indicated by the arrow A in FIG.

As shown in FIG. 7, the evaporation source hearth 2 and the substrate 7 on which the film is formed are arranged in the vacuum chamber 3, and the elongated rectangular permanent magnet 9 is placed outside the vacuum chamber 3 and below the evaporation source hearth 2. Ion plating can also be performed by disposing. In this case, the portion of the bottom surface of the vacuum chamber 3 sandwiched between the evaporation material hearth 2 and the permanent magnet 9 needs to be made of a material that does not shield the magnetic field. As described above, the width, thickness, plasma density, and the like of the sheet plasma 8 can be controlled outside the vacuum chamber as desired by changing the permanent magnet 9 via the bottom surface of the vacuum chamber 3. it can. The width, length, and plasma density of the sheet plasma vary depending on the power applied to the evaporating raw material 2, the permanent magnet 9, the arc discharge plasma flow source 1, and the like. Can be changed freely, sufficient control of the sheet plasma becomes possible. As described above, the permanent magnet 9
Is arranged outside the vacuum chamber 3, it is possible to change the type and shape of the permanent magnet 9 or change the distance between the permanent magnet 9 and the evaporation material hearth 2 without changing the inside of the vacuum chamber 3. Becomes possible. This is a multi-layered film of different materials,
It greatly contributes to stabilization for continuous production.

Further, a discharge gas is introduced from the discharge gas inlet 11. Further, it is desirable that the vacuum chamber 3 is maintained at about 10 ⁻³ Torr or less by the exhaust means.

As the evaporation raw material 10 used in the present invention, metals, alloys, oxides thereof, borides, carbides, silicides,
A tablet made of a nitride or a mixture containing one or more of these can be used, and is not particularly limited. However, when a metal oxide film is formed, when a metal oxide tablet is used, This is preferable because it is easy to control the film forming conditions and a good quality film can be obtained. In particular, when an indium oxide film containing tin is formed, a tablet of indium oxide containing 5 to 10% by weight of tin is preferable because a very low-resistance film can be obtained.

In the present invention, the discharge gas introduced from the gas inlet 11 into the vacuum chamber 3 is not particularly limited,
Inert gases such as Ar and He are preferred. The gas atmosphere in the vacuum chamber 3, in addition to an inert gas such as such Ar, the gas introducing means 12 provided in the vacuum chamber 3, and O _2, N ₂ as a reactive gas, 0-50 volume % May be added.

As the substrate 7 on which a thin film is formed in the present invention, a substrate or a film made of glass, plastic, or metal can be used, and is not particularly limited. However, in the method of the present invention, even if the substrate is not heated. Since a high quality film can be obtained, those having low heat resistance, such as a substrate or film made of plastic or a glass plate having an organic polymer film in advance, such as a glass substrate for a liquid crystal color display having a color filter film, etc. Applicable enough.

In the present invention, the thin film formed on the base 7 includes a metal film, an alloy film, a metal oxide, a nitride, a boride,
A thin film or the like made of silicide, carbide or a mixture containing one or more of these can be formed, and is not particularly limited. However, the method of the present invention provides a transparent conductive film having low resistance and high transmittance. Perfect to get. Suitable examples of such a transparent conductive film include an indium oxide film containing tin, a tin oxide film containing antimony, and a zinc oxide film containing aluminum. The method of the present invention comprises a transparent electrode for a display such as a liquid crystal display element, an electrode for a solar cell, a heat ray reflective glass, an electromagnetic shielding glass, a low emissivity (Low-Emissiv).
ity) It can be applied to the production of glass and the like. In the present invention, during film formation, the substrate 7 may be stationary or may be transported. In particular, the film is formed while being conveyed in the direction from left to right in FIG. 1 or right to left, that is, in the direction perpendicular to the back side of the paper in FIG. 2 or in the direction perpendicular to the back side in the vertical direction in FIG. This is preferable because a uniform film can be continuously formed in the width direction of the sheet plasma.

In the present invention, if the length of the DC power supply 4 applied to the arc discharge plasma flow source 1 and the length of the permanent magnet 5 for transforming the plasma flow into a sheet, the strength of the magnetic force, and the like are adjusted, the thickness is reduced.
A sheet plasma having a width of about 0.5 to 3 cm and a width of about 10 to 50 cm can be easily formed, and the width of the sheet plasma on the hearth 2 and the shape of the plasma can be changed by changing the length of the permanent magnet 9 and the strength of the magnetic force. , The density can be changed.

Further, as shown in FIG.
Is generated by magnetic field means (specifically, the permanent magnet 5 in FIG. 4) to form a large-area sheet plasma by adjoining the sheet plasma deformed into a sheet shape on the same plane. It can also be bent over the placed hearth 2 to evaporate. FIG. 4 is a diagram showing a case where three devices as shown in FIG. 1 are arranged adjacent to each other as viewed from the top to the bottom of FIG. If in this manner the adjacent multiple sheets plasma, according to the permanent magnet 5, in order to maintain the symmetry of the magnetic field component B _x in the width direction of the sheet plasma, on an extension of a line connecting a plurality of permanent magnets 5 and the sheet plasma , It is necessary to arrange another pair of permanent magnets 15 on the outside of both ends.

The hearth 2 may be an elongated one as shown in FIG. 4 or a plurality of relatively short hearths having different evaporation materials. In either case, the substrate on which the thin film is formed may be stationary or may be transported. In this case, when the substrate is transported in the direction of arrow C, a large-area thin film can be formed very uniformly at high speed.

In addition, by incorporating a film forming apparatus as shown in FIG. 1 into a part of an in-line type film forming apparatus, it is possible to continuously produce a multilayer film in combination with another film forming apparatus such as a sputtered film and a horizontal deposition film. It is. When forming a multi-layer film, it is important to form a multi-layer material by the most suitable method.Especially, in the case of a large area, the film thickness distribution has been a problem in the vapor deposition method. The use of a sheet plasma as in the invention greatly improves the performance.

In addition, as shown in FIG. 6, a plurality of hearths may be provided, and different evaporation raw materials 10A, 10B, and 10C may be put in for ion plating. In FIG. 6, each hearth 2A, 2B, 2
It is desirable that each of C and the permanent magnets 9A, 9B, 9C have at least the same width as the base 7 as shown in FIG.
By selecting the switches 13A, 13B, and 13C as desired, a film having one or more compositions can be formed on the substrate 7. FIG. 6 shows that only the switch 13B is turned ON,
The sheet plasma 8 is concentrated on the top,
10B shows a case where a film is formed by evaporating 10B.
In particular, in the case of an in-line type apparatus, a job change for changing the type of the evaporation raw material is not required, and a significant cost reduction can be achieved. Also, switch two or more of the switches
By turning on and applying the desired power to the DC power supplies 4A, 4B, 4C, the density of the sheet plasma incident on the corresponding evaporating material is adjusted, the evaporation rate is controlled, and the composition of the multi-component film is controlled. It can also be formed. If the thickness of the hearths 2A, 2B, and 2C (the length in the left-right direction in FIG. 6) is reduced and various hearths are brought close to each other, a film composed of multiple components having a specific composition can be formed uniformly. In particular, it is more preferable to transport the substrate 7 in the direction of the arrow D or D '.

In the present invention, a film formation rate of about 3000 to 10000Å / min can be obtained, and a high-quality film can be formed at a much higher speed than the conventional ion plating method.

For example, IT as a raw material for evaporation of indium oxide containing tin
When an O film is formed, an ITO film having a specific resistance of 3 × 10 ⁻⁴ Ω · cm or less can be obtained at a film forming rate of about 5000 ° / min.

[Operation] In the present invention, since the sheet plasma used is an arc discharge, the density of the plasma is 50 to 50 in comparison with the glow discharge type plasma used in the conventional magnetron sputtering or ion plating. It is 100 times higher, the ionization degree of the gas is several tens%, and the ion density, electron density, and neutral active species density are very high. By converging such a high-density plasma on the evaporation material, it is possible to take out a very large number of particles from the evaporation material, and to form a film 3 to 10 times as fast as the conventional ion plating method. Can be realized. In addition, many of the atmospheric gases such as oxygen and argon take highly reactive ions and neutral active states, and in addition, the evaporated particles pass through a high-density sheet plasma before reaching the substrate. It becomes a highly reactive neutral active species. As a result, the reactivity on the substrate is increased, and a transparent conductive film having a low specific resistance can be realized at a higher deposition rate than before, without heating the substrate.

[Example] A glass plate was used as the substrate 7, and an ITO film of a conductive oxide was vapor-deposited by a method described below. First, the degree of vacuum in the vacuum chamber 3 is reduced to 2 × 10 ⁻⁵ Torr, and then O ₂ gas is introduced to 4.0 × 10 ⁻⁴ Torr, as shown in FIG. 1 having a composite cathode as shown in FIG. Using a suitable plasma generator, the DC power supply 4 was set to 250 A and 70 V to perform arc discharge. The distance between the hearth 2 and the substrate 7 was about 60 cm, and the substrate was fixed. A film having a thickness of 14800 mm, a specific resistance of 3.05 × 10 ⁻⁴ Ω · cm, and a visible light transmittance of 70% (substrate glass 92%) was obtained. These are at a film forming rate of 5000 l / min, which is extremely faster than a method using an EB gun or the like. As the deposition performed without heating the substrate, one having a considerably low specific resistance was obtained.

[Effects of the Invention] According to the present invention, thin films of various compounds can be formed at high speed and with high quality without heating the substrate. Further, since an optimum plasma flow can be generated according to the type of the thin film, an optimum film can be formed. In other words, by increasing the width of the sheet plasma, the film thickness distribution on the substrate 7 can be reduced for a large-area substrate, and conversely, the sheet plasma can be reduced by using a small permanent magnet 9. By forming the dots, the degree of concentration on the hearth 2 can be increased, and materials that are difficult to evaporate can be easily evaporated.

Further, in the present invention, it is possible to further improve the film thickness distribution over a large area by translating the hearth 2 and the magnet 9, and it is possible to apply a plurality of hearths 2 to a large-area multilayer film. Becomes

Further, by moving the hearth 2 and the permanent magnet 9 relatively, the utilization efficiency of the evaporating substance 10 in the hearth can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of an example of an apparatus used for performing ion plating according to the present invention, FIG. 2 is a cross-sectional view of an arc in FIG. 1, and FIG. 3 is an arc discharge plasma used in the present invention. FIG. 4 is a cross-sectional view of an example of a composite cathode as a cathode of a generator, FIG. 4 is a schematic diagram in the case of using a large-area sheet plasma having sheet plasma adjacent thereto, and FIG.
FIG. 6 is a schematic explanatory view showing a state in which a hearth and a permanent magnet are relatively moved, FIG. 6 is a schematic explanatory view in a case where a plurality of hearths are provided, and FIG. 7 is a figure for performing ion plating according to the present invention. Is a schematic diagram showing a basic configuration of another example of an apparatus for performing the above. 1: Arc discharge plasma flow source 2: Hearth (anode) 3: Vacuum chamber 4: DC power supply for plasma generation 5: Permanent magnet 6: Air-core coil 7: Substrate 8: Sheet plasma 9: Permanent magnet 10: Evaporated raw material 11 : Discharge gas inlet 12: Reaction gas inlet 13: Switch 21: Composite cathode 22: First intermediate electrode with built-in annular permanent magnet 23: Second intermediate electrode with built-in air core coil 51: LaB ₆ main cathode 52: Ta pipe Auxiliary cathode 53: Disk made of W for protecting the cathode 54: Cylinder made of Mo 55: Disk shaped heat shield made of Mo 56: Cooling water 57: Cathode support made of stainless steel 58: Gas inlet

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Naoki Hashimoto 20-3 Suwazaka, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-63-50463 (JP, A) JP-A-62-63669 (JP, A) JP-A-62-10068 (JP, A)

Claims (2)

(57) [Claims] 1. An arc discharge plasma flow generated by an arc discharge is deformed into a sheet by applying a magnetic field, and is elongated in the width direction of the sheet plasma under an evaporation raw material hearth placed below the sheet plasma. A permanent magnet is placed, and the sheet-like plasma is bent by the magnetic field generated by the permanent magnet and guided on the evaporation raw material hearth, and the moving direction is parallel to the base and perpendicular to the width direction of the sheet-like plasma. By relatively moving the evaporation raw material hearth and the permanent magnet under it so that it is in the direction,
An ion plating method comprising: evaporating an evaporation material; and forming a film on a substrate placed above the evaporation material. 2. An arc discharge plasma flow generated by an arc discharge is deformed into a sheet by applying a magnetic field, and is elongated in a width direction of the sheet plasma under an evaporation raw material hearth placed below the sheet plasma. A permanent magnet is placed, and the sheet-like plasma is bent by the magnetic field generated by the permanent magnet and guided on the evaporation raw material hearth, and the moving direction is parallel to the base and perpendicular to the width direction of the sheet-like plasma. Ion, characterized by evaporating the evaporating material by translating the evaporating material hearth and the permanent magnet thereunder so as to be in the same direction, and forming a film on a substrate placed above the evaporating material. Plating method.