JPH07138743A - Ion plating device - Google Patents

Abstract

PURPOSE:To provide the ion plating device of a simple structure capable of forming films of nearly a uniform thickness on the surface of a substrate. CONSTITUTION:This ion plating device is provided with a bar magnet 11a arranged in a hearth 11 as an incident beam direction adjusting means for adjusting the incident direction of a plasma beam on the hearth 11 and an annular permanent magnet 15 disposed near the upper part of the hearth 11 in such a manner that its central axis is aligned to the central axis of the hearth 11. As a result, the cusp magnetic field is formed above the incident surface of the hearth 11 by synthesis of the magnetic lines of force by the bar magnet 11a and the magnetic lines of force by the annular permanent magnet 15, by which the correction of the plasma beam is executed. As a result, the plasma beam is made incident nearly linearly from right above the material to be deposited by evaporation of the hearth 11 by the plasma beam and, therefore, the thin films having the uniform film thickness are formed on the surface of the substrate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a metal film or an alloy film by depositing film forming material vapor particles generated by evaporation and ionization of a material in a vacuum container on the surface of a substrate by ion plating. The present invention relates to an ion plating device.

[0002]

2. Description of the Related Art Conventionally, there is an ion plating apparatus of this type using an arc discharge type plasma gun as a plasma source for performing ion plating.
In this ion plating, the material vapor vaporized in the vacuum container is ionized by plasma, and the film forming material particles are attached to the surface of the substrate provided in the vacuum container to form a metal film or an alloy film. To film.

Therefore, the ion plating apparatus is provided with a heating power source for melting the material and a plasma generating means for generating plasma. For example, when a single metal is used as the material in the crucible or hearth, a single metal film is formed on the surface of the substrate. Also, a film of the compound can be obtained by the reactive ion plating method using the plasma of the reactive gas, and if several different metals are used,
An alloy film is formed on the surface of the substrate. Moreover, a film formed by ion plating has an advantage that a film quality that is dense and has excellent adhesiveness can be easily obtained, as compared with a film formed by ordinary vacuum deposition.

By the way, generally, as means for heating a metal, resistance heating, induction heating, heating by an electron gun (EB), arc discharge [for example, discharge by a hollow cathode gun,
Discharge using a pressure gradient type plasma gun (also called Uramoto gun), multi-arc discharge] and the like. Further, examples of means for generating plasma include DC glow discharge, RF discharge, microwave discharge, ECR discharge, DC arc discharge and the like.

Therefore, for the ion plating, various methods have been proposed in which such heating means and plasma generating means are combined. Here, for industrial reasons, EB + RF method, EB + DC arc method,
A hollow cathode (HCD) system and a pressure gradient type plasma gun system will be described.

The EB + RF system and the EB + DC arc system are ones in which the material is vaporized by using EB and further RF discharge or DC arc discharge is used as a plasma generation source, respectively. The HCD method uses a metal pipe as a cathode and a crucible or a hearth on which a material to be vaporized is placed as an anode to perform arc discharge, and the heat and plasma generated at this time simultaneously vaporize and ionize the metal. is there. The pressure gradient plasma gun method is basically the same as the HCD method, and arc discharge is performed between the cathode gun and the anode crucible or hearth (hereinafter, described as a case where only the crucible is used). , Vaporization and ionization of materials are performed simultaneously.

Of these, the pressure gradient type plasma gun system is
Compared to other ion plating methods, the cathode has a longer life, and the shape of plasma can be adjusted and controlled by a magnetic field. Further, in the pressure gradient type plasma gun method, the cathode is not damaged even when the plasma of oxygen gas is used, and an electrode separately required for another ion plating method is not required as a plasma generating means for achieving ionization. .

For these reasons, the pressure gradient type plasma gun type ion plating is more advantageous than other types of ion plating apparatus in terms of productivity and facility setting when constructing the apparatus. There is.

FIG. 5 is a side sectional view showing the basic construction of an ion plating apparatus which employs reactive ion plating of the pressure gradient type plasma gun system. This ion plating apparatus includes a vacuum container 10 whose inside is kept in a vacuum atmosphere and which is provided with a gas supply port for supplying a reaction gas. A hearth 11 is provided at the bottom of the vacuum container 10, and a material is placed on the hearth 11. Material on this hearth 11 (vapor deposition material)
Is dissolved, evaporated and ionized by the plasma beam described later. A substrate 12 is arranged to face the hearth 11 substantially at the center of the vacuum container 10. The material vapor evaporated and ionized on the hearth 11 adheres to the surface of the substrate 12 as described later.

A mounting port F is provided in the vacuum container 10, and a pressure gradient type plasma gun (beam generator) 20 is mounted in the mounting port F. Pressure gradient type plasma gun 2
0 is a cathode part 21 that is arranged to face each other with a predetermined interval,
A permanent magnet 22 and an intermediate electrode including a ring-shaped electromagnetic coil 23 are provided. A steering coil 25 is provided on the outer periphery of the mounting port F outside the vacuum container 10. The beam generated by the cathode part 21 is converged by the permanent magnet 22 and the electromagnetic coil 23, and is guided onto the hearth 11 by the steering coil 25. At this time, plasma is generated between the hearth 11 inside the vacuum container 10 and the hearth 11.

The hearth 11 and the pressure gradient type plasma gun 2
A power supply circuit (not shown) is connected between 0 and 0, and the hearth 11 and the pressure gradient type plasma gun 20 are supplied with power from this power supply circuit. Generally, the hearth 11 is grounded, and the cathode portion 2 of the pressure gradient type plasma gun 20 is connected to the hearth 11.
1 is set to a negative potential. In other words, the hearth 11 electrically forms an anode with respect to the pressure gradient type plasma gun 20. A bar magnet 11 a is embedded in the hearth 11.

The substrate 12 is rotatably attached to the upper portion of the vacuum container 10 via a rotary shaft 13, and the rotary shaft 13
Is connected to a motor 14 installed on the upper surface of the vacuum container 10. The substrate 12 can be rotated by rotating the rotating shaft 13 with the motor 14. A negative voltage is applied to the substrate 12 by a power source (not shown) so that the substrate 12 has a negative potential. That is, the substrate 12 electrically forms a cathode with respect to the hearth 11.

The operation of the ion plating apparatus having such a structure will be described with reference to FIG. When power is supplied between the hearth 11 and the pressure gradient type plasma gun 20 by the power supply circuit, the plasma beam P is generated in the vacuum container 10. The generated plasma P is guided to the hearth 11 by the steering coil 25, and the material (vapor deposition material) on the hearth 11 is evaporated and ionized in the plasma beam P to generate film forming material particles. The film forming material particles are attracted to the substrate 4 having a negative potential with respect to the hearth 11, and the film forming material particles adhere to the surface of the substrate 4 to form a film.

The pressure gradient type plasma gun 20 and the above-mentioned HC
When performing ion plating by an ion plating device using an arc discharge type plasma gun such as a D gun, as shown in FIG. 6, the plasma beam P is obliquely incident on the hearth 11 and vapor deposition on the hearth 11 is performed. Figure 6
As indicated by the arrow G in FIG. Moreover, since the protruding direction G changes depending on the beam current flowing through the cathode portion 21 of the pressure gradient type plasma gun 20, the protruding direction G of the vapor deposition material is not constant.

This state is shown in FIG. The ordinary plasma beam P is incident on the incident surface of the hearth 11 along the locus Bn in FIG. That is, the normal plasma beam P along the locus Bn is incident at an angle θ with respect to the normal to the incident surface of the hearth 11. This inclination angle θ is affected by the magnetic force lines Ha of the bar magnet 11a embedded in the hearth 11.
The locus of the plasma beam P weaker than the normal plasma beam P along the locus Bn is shown by Bw. The weak plasma beam P along the locus Bw is also affected by the magnetic field lines Ha of the bar magnet 11a embedded in the hearth 11.

In FIG. 8, the substrate 12 when the normal plasma beam P is incident on the incident surface of the hearth 11 along the locus Bn.
An example of measurement of the film thickness distribution at The measurement conditions at this time are as follows. A substrate 12 having a size of 150 × 150 mm was used. Further, taking the above-mentioned direction G of the vapor deposition material into consideration, the substrate 12 is not directly above the hearth 11 but the substrate center Cs is away from the pressure gradient type plasma gun 20 with respect to the hearth center Ch and in FIG. They were arranged on the front side while being shifted by 30 mm. The distance between the substrate 12 and the hearth 11, that is, the substrate height was 252 mm. The substrate 12 was divided into a lattice shape, and 36 spaces excluding the outer peripheral portion were distinguished by numbers 1 to 36 in each divided space. In each space, the number N of this space is shown in the upper column, the percentage A (average about 2.8%) in the entire space is shown in the middle column, and the actually measured value B (μm) of the film thickness is shown in the lower column.

As is apparent from FIG. 8, the measured value B (percentage A) of the film thickness on the substrate 12 is about 2.2 μm.
(About 2.8%) as an average of 0.8 to 4.0 μm (1.
It is distributed in a very wide range of 0 to 5.1%). Despite the fact that the substrate center Cs is displaced from the hearth center Ch, the thickest part is the front side (space numbers N are 24 and 27) away from the pressure gradient type plasma gun 20 side.
In the part. It is considered that this is because the incident angle of the plasma beam P with respect to the hearth 11 is inclined.

In order to deal with such a drawback, conventionally, the following two methods have been used. A method of modifying the plasma beam P by providing an electromagnetic coil near the upper part of the incident surface of the hearth 11 (see, for example, Japanese Patent Application No. 4-70552). A method of tilting the bar magnet 11a in the hearth 11.

[0019]

However, the above method has the following drawbacks. In the method of
The structure is complicated by the need for equipment such as the coil body, current introduction system, and coil cooling system. Further, in order to correct the plasma beam P in a desired direction, it is necessary to use a coil power supply capable of passing a large current through the electromagnetic coil. In the above method, even if the bar magnet 11a is tilted, it is not completely solved because it is affected by the magnetic field lines Ha, and moreover, a mechanism for tilting the bar magnet 11a corresponding to the beam current is required, so that the structure is complicated. Becomes Moreover, since the tilt angle of the bar magnet 11a must be adjusted for each beam current, control becomes difficult.

A technical object of the present invention is to provide an ion plating apparatus using an arc discharge type plasma gun having a simple structure capable of forming a film having a substantially constant film thickness on the surface of a substrate.

[0021]

According to the present invention, a plasma beam is generated from a beam generator, the plasma beam is guided to the incident surface of the hearth, and the vapor deposition material on the hearth is vaporized.
In an ion plating device that performs ion plating by depositing ionized, evaporated / ionized vapor deposition material on the surface of a substrate that is placed opposite to the hearth, adjusting the incident beam direction to adjust the incident direction of the plasma beam to the hearth And a means for adjusting the incident beam direction, wherein the means for adjusting the incident beam has a bar magnet disposed in the hearth, and an annular permanent magnet provided near the upper portion of the hearth so that the central axis matches the central axis of the hearth. .

[0022]

By combining the magnetic field lines of the bar magnet and the magnetic field lines of the annular permanent magnet, a cusp magnetic field is formed above the entrance surface of the hearth to correct the plasma beam.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description of the ion plating apparatus of the present invention with reference to the drawings.

FIG. 1 is a side sectional view showing the basic construction of an ion plating apparatus according to an embodiment of the present invention. The ion plating device shown in the figure employs reactive ion plating by a pressure gradient type plasma gun system, as in FIG. The difference from the one shown in FIG. 5 is that the annular permanent magnet 15 is provided near the upper portion of the hearth 11. Explaining in a little detail, the annular permanent magnet 15
Is provided in the vicinity of the upper portion of the hearth 11 so that its central axis matches the central axis of the hearth 11. In this embodiment,
A substrate 12 is arranged directly above the hearth 11 so as to face the hearth 11.

In this way, the annular permanent magnet 15 is attached to the hearth 11
When placed near the upper part of the bar magnet 1, as shown in FIG.
A cusp magnetic field Hc is formed above the entrance surface of the hearth 11 by combining the magnetic force line Ha generated by the magnetic field 1a and the magnetic field line Hb generated by the annular permanent magnet 15. This cusp magnetic field Hc corrects the trajectory of the plasma beam P, and the plasma beam P is struck by the hearth 11
It is possible to make the incident almost linearly from directly above the vapor deposition material placed thereon. As a result, a thin film having a uniform film thickness can be formed on the surface of the substrate 12 (FIG. 1).

FIG. 3 shows an example of measuring the film thickness distribution of a thin film on the substrate 12 when the plasma beam P is incident on the hearth 11 in the ion plating apparatus according to the present invention.
The measurement conditions at this time are as follows. A substrate 12 having a size of 150 × 150 mm was used. Also, the substrate 12
Was arranged directly above the hearth 11, that is, the substrate center Cs and the hearth center Ch were aligned. Board 12 and hearth 1
The distance between 1 and the substrate height was 126 mm.
The substrate 12 is not rotated. The substrate 12 was divided into a lattice shape, and in order to distinguish 36 spaces excluding the outer peripheral portion in each of the divided spaces, they were numbered 1 to 36. In each space, the number N of this space is shown in the upper column, and the percentage A (average about 2.8%) in the entire space is shown in the middle column.
The actually measured value B (μm) of the film thickness is shown in the lower column.

As is apparent from FIG. 3, the measured value B (percentage A) of the film thickness on the substrate 12 is about 2.2 μm.
(About 2.8%) on average 1.4 to 3.0 μm (1.
It is distributed in a very narrow range of 8 to 3.9%). That is, although the height of the substrate 12 is lower than that in the case of FIG. 8, a thin film having a substantially constant film thickness is formed, and the average thickness is about 2.8.
It turns out that there are many values close to%.

Although the ion plating apparatus of the embodiment is based on the pressure gradient type plasma gun method, an equivalent ion plating apparatus can be constructed by using the HCD method instead. A crucible may be used instead of the hearth 11. Instead of the integrally formed annular permanent magnet 15, a small number of small rod-shaped permanent magnet pieces 15a arranged in an annular shape as shown in FIG. 4 may be used. In this case, in order to make the magnetic force lines Hb uniform, it is preferable to provide iron cores above and below the annular permanent magnet 15a. Further, the annular permanent magnet 15 may be provided so as to be vertically movable with respect to the bar magnet 11a. As a specific example thereof, a liner may be interposed on the lower surface of a bracket that supports the annular permanent magnet 15, and the annular permanent magnet 15 may be vertically driven by a known drive device (for example, a cylinder).

[0029]

As described above, according to the ion plating apparatus of the present invention, the bar magnet is embedded in the hearth, and the annular permanent magnet is arranged in the vicinity of the hearth so that the central axis of the bar magnet is aligned. By forming the cusp magnetic field above the incident surface, the plasma beam can be made to enter substantially linearly from directly above the vapor deposition material placed on the hearth. Since the combination of the bar magnet and the annular permanent magnet is used as the incident beam direction adjusting means, it has the following advantages as compared with the conventional one. The structure is simple.
No coil power required. Since the magnetic field generated by the annular permanent magnet is stronger than that generated by the electromagnetic coil, the correction force of the plasma beam is large. There is no need for control. The influence of the beam incident angle on the beam current is small.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a basic configuration of an ion plating apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining directions of magnetic force lines in the vicinity of a hearth used in the ion plating apparatus shown in FIG.

3 is a diagram showing an example of measurement of a film thickness distribution of a thin film on a substrate when a plasma beam is incident on a hearth in the ion plating apparatus shown in FIG.

FIG. 4 is a perspective view showing a modified example of an annular permanent magnet used in the ion plating apparatus of the present invention.

FIG. 5 is a side sectional view showing a basic configuration of a conventional ion plating apparatus.

6A and 6B are diagrams for explaining the operating principle of the conventional ion plating apparatus shown in FIG. 5 and its problems.

FIG. 7 is shown for explaining the directions of magnetic force lines near the hearth used in the conventional ion plating apparatus shown in FIG.

8 is a diagram showing an example of measurement of a film thickness distribution of a thin film on a substrate when a plasma beam is incident on a hearth in the ion plating apparatus shown in FIG.

[Explanation of symbols]

 11 Haas 11a Bar magnet 12 Substrate 15 Annular permanent magnet

Claims (1)

[Claims] 1. A plasma beam is generated from a beam generator, the plasma beam is guided to the entrance surface of the hearth, the vapor deposition material on the hearth is vaporized and ionized, and the vaporized and ionized vapor deposition material is opposed to the hearth. In an ion plating apparatus for performing ion plating by adhering to the surface of a substrate that is arranged in the same manner, an ion beam direction adjusting means for adjusting an incident direction of the plasma beam with respect to the hearth is provided, and the incident beam direction adjusting means is provided. A bar magnet disposed in the hearth, and an annular permanent magnet provided near an upper portion of the hearth so that a central axis thereof coincides with a central axis of the hearth. The cusp magnetic field is formed above the entrance surface of the hearth by the combination with the magnetic field line to correct the plasma beam. Ion plating apparatus characterized by.