JPH08104981A - Pvd device - Google Patents

Abstract

PURPOSE: To provide a PVD device by which a film is formed even under atmospheric pressure and a clean film uniform in thickness is obtained. CONSTITUTION: This device is provided with a crucible 5, a substrate holder 7 positioned above the crucible 5 and an induction coil 6 furnished around the crucible. A raw material M is floated in the crucible by the electromagnetic force of the coil 6, hence the raw material is not contaminated, and a high- quality film is obtained.

Description

Detailed Description of the Invention

[0001] The present invention relates to a PVD apparatus and a vapor deposition method.

[0002]

2. Description of the Related Art PVD has been conventionally used in the field of semiconductor devices and the like.
Film formation by (vapor deposition, ion plating) is used. In general, a crucible in which a refractory is set or laid on water-cooled copper is placed in a chamber, the raw material in the crucible is melted and evaporated by an electron beam, and this is deposited on a substrate to form a film. On the other hand, as a metal melting technology,
Using a cold crucible (water-cooled crucible made of metal),
There is known a cold crucible method in which a heated object is levitated and melted by electromagnetic force inside (Journal of the Institute of Electrical Engineers of Japan, 11
Vol. 4, No. 3, 1994: pp. 156 et seq.).

[0003]

However, the conventional PVD
The technology has the following drawbacks. Since the melted raw material is in contact with the inner surface of the crucible, refractory components are mixed in the molten metal, and the formed film is easily contaminated with impurities. The electron beam operates only at low pressures below about 10 ^-4 torr and requires evacuation means to achieve this condition. Usually, an evacuation means capable of controlling the inside of the chamber to 10 ^-5 torr or less is used.

To make the film thickness uniform, the pressure in the chamber may be raised. However, due to the use of the electron beam,
You cannot take this measure. Therefore, the substrate is usually rotated and revolved, and a driving means for the substrate is required. Since the electron beam concentrates energy at one point, it inevitably causes a large temperature distribution on the surface of the molten metal, and the amount of evaporation also largely varies. Normally, the electron beam is scanned over the molten metal to make the evaporation amount uniform, but a mechanism for this is required, which increases the cost.

[0005]

The present invention has been made in order to solve such a problem, and its gist is to apply the cold crucible method to PVD technology. That is, the PVD apparatus of the present invention is characterized by including a crucible having a cooling mechanism, a substrate holder located above the crucible, and an induction heating device provided on the outer periphery of the crucible. Here, a high frequency coil for ionizing the vapor of the raw material generated by melting in the crucible may be provided between the crucible and the substrate and used as an ion plating device. Further, in each of the above-mentioned devices, at least one of the atmosphere gas introduction mechanism, the vacuum evacuation mechanism, and the pressurization mechanism is provided, so that various atmospheres and pressures can be adjusted for film formation. It is considered that the crucible has a structure in which the side wall and the bottom surface are integrated and the crucible is independent of each other. Here, the former is a floating type and the latter is a semi-floating type.

[0006] By using these devices, the molten material can be levitated or erected in the crucible for vapor deposition. That is, the vapor deposition method of the present invention is a vapor deposition method in which a raw material is melted in a crucible and vapor generated is deposited on a substrate installed on the upper part of the crucible to form a film, and the raw material melted by induction heating is used as a crucible side wall. It is characterized in that vapor deposition is performed as non-contact. The atmospheric pressure here is 10 ^-4 torr.
It may be r or more and less than 1 atm, or 1 atm or more. When performing ion plating, the generated raw material vapor may be ionized.

[0007]

[Function] Since the cold crucible method is a technology for melting a metal, it produces a metal vapor according to the melting conditions. The present invention uses this steam to form a film. (Prevention of formation film contamination) When an alternating current (for example, a high frequency of about 1 kHz) is applied to the induction coil arranged around the crucible, an alternating magnetic field is generated, and an eddy current is generated in the crucible and the heating target (deposition material) inside the crucible. Induced. Here, since repulsive force acts on both, in the levitation type, the heating target is in a state of being levitated in the crucible, and in the semi-levitation type, it contacts the bottom crucible,
The standing state is not in contact with the side wall. Then, the induced eddy current melts the object to be heated by Joule heat. Therefore, the object to be heated is melted without contacting the crucible or with very slight contact, so that the contamination from the crucible, which has been a conventional problem, can be suppressed.

(Uniformization of components by stirring molten metal) The repulsive force acting on the inner surface of the crucible and the object to be heated continues to act even after the raw materials are melted. Since the eddy current has the property of concentrating on the surface as the electric resistance of the raw material increases, this repulsive force acts strongly near the surface of the molten metal. That is, in the raw material molten metal, it acts as a force from the surface toward the center and agitates the molten metal.
Therefore, when a raw material of a plurality of components is used, the components can be made uniform by this stirring. In addition, since the entire surface of the molten metal is heated substantially uniformly in principle, it is easy to uniformly disperse the generated vapor, and a scanning mechanism for vapor deposition using an electron beam is not required.

(Film formation under a pressure of 10 ^-4 torr or more) Furthermore, since it is melted by electromagnetic induction, it is not necessary to reduce the atmosphere pressure. This is decisively different from the electron beam method. It is known that when the pressure in the chamber is increased, the mean free path of vapor particles is shortened and scattered, and as a result, the film thickness distribution on the substrate is reduced, but in the case of vapor deposition using an electron beam, The pressure cannot be increased. On the other hand, in the vapor deposition according to the present invention using the cold crucible method, not only in the vacuum but also at 10 ⁻⁴ torr.
As described above, it is possible to form a film even at atmospheric pressure or higher. Therefore, vapor deposition can be performed without using an exhaust means, and the film thickness can be made uniform. Table 1 shows the relationship between the pressure and atmosphere during vapor deposition and the necessary mechanism.

[0010]

[Table 1]

[0011]

Embodiments of the present invention will be described below. (Embodiment 1) First, a semi-floating type PVD apparatus will be described. As shown in the figure, a crucible 1 for containing a vapor deposition material M
And the induction coil 2 arranged on the outer periphery thereof, and the substrate holder 3 is provided on the upper part of the crucible 1. The crucible 1 has a cylindrical side wall 1A and a bottom surface 1B independent of the side wall 1A. In general, it is preferable that the refractory is attached to water-cooled copper, but basically, a conductor that generates an eddy current may be used. The bottom of the crucible is a portion that supports the molten metal, and it is preferable that the crucible is made of the same material as the raw material M or a material that does not react with the raw material M in order to suppress contamination of the formed film. On the other hand, the substrate holder 3 holds the substrate S on which the vapor deposition film is formed, and is arranged so that the substrate S can be mounted parallel to the opening surface of the crucible.

In such a device, when a high frequency current is applied to the induction coil 2, an alternating magnetic field is generated and the crucible 1
And an eddy current is induced in the raw material M. At this time, since the AC magnetic field from the induction coil 2 hardly reaches the bottom surface 1B, the raw material M is supported by the bottom surface 1B. However, since the side wall 1A and the raw material M repel each other by an electromagnetic force, the raw material M is supported. Is not in contact with the side wall 1A and is melted in an upright state. The dissolved raw material M is separated into an upper liquid phase portion M1 and a lower solid phase portion M2 which is in contact with the bottom surface of the crucible. Then, the raw material vapor generated by the melting reaches the substrate S set in the holder 3 to form a film. In the case of this example, the raw material M does not float and is not in complete contact with the crucible,
The raw material that comes into contact with the bottom surface 1B is the solid phase portion M2, and it is considered that the mixing of impurities into the liquid phase portion M1 where evaporation of the raw material occurs is extremely small. A bias voltage may be applied to the substrate side, and as shown in Table 1 above, a vacuuming mechanism or a pressurizing mechanism may be provided depending on the atmosphere. In Table 1, "(vacuum)" is set in an atmosphere with a pressure of 760 Torr or more.
Is used because it is used for removing air once. Such a semi-floating device does not require enough energy to levitate the raw material, and is therefore excellent in energy efficiency.

(Second Embodiment) Next, a levitation type ion plating apparatus will be described. The basic configuration is the same as that of the first embodiment, but the configuration of the crucible 5 is different from that of the crucible 5 in that a high-frequency coil 8 is provided between the crucible 5 and the substrate S. In the crucible 5 of this example, the side wall and the bottom surface are integrated,
The raw material M is completely levitated in the crucible. The material of the crucible 5 is the same as that of the first embodiment. Although not shown, the crucible having a plurality of axial slits may be divided from the side wall to the bottom surface. The larger the number of divisions, the larger the levitation force and the stability of the molten metal can be obtained. When the slit width is wide, the levitation force is large, but the stability of the molten metal tends to decrease.

When a high frequency current is applied to the induction coil 6 in such an apparatus, an eddy current is generated on both the inner surface of the crucible and the raw material M. At this time, since the eddy current flowing through the inner surface of the crucible and the eddy current flowing through the raw material M flow in opposite directions,
The raw material M is levitated by the repulsion of the electromagnetic force generated between these eddy currents, and further the Joule heat is generated by the specific resistance of the raw material M to be heated and melted. Although steam is generated from the melted raw material, while reaching the substrate S,
It is excited by the action of the high-frequency coil 8 and reaches the substrate S after being ionized. As described above, according to this example, the raw material M is completely out of contact with the crucible 5, and the contamination of the film formation can be prevented. In the case of this example, it is also possible to form a compound with the vapor deposition material on the substrate by appropriately introducing a gas according to the purpose. In that case, as shown in Table 1, a gas introducing mechanism, a vacuuming mechanism, or a pressurizing mechanism may be provided as appropriate. Also, a bias voltage may be applied to the substrate side. Furthermore, it is possible in principle to use a DC bias instead of a high frequency.

(Test Example) Vapor deposition was performed using the apparatus shown in FIG. The main conditions are as follows. Raw material: Fe Raw material weight: 9 kg (initial) Skull outer diameter: 127 mm Substrate material: SUS304 Molten metal temperature: Approx. 1550 ° C Atmosphere: Air Distance between substrate and molten metal: Approx. 150 mm Electric power: 150 kW Frequency: 9.9 kHz Under these conditions 2 Film formation for 2 minutes, average film formation speed 2 nm / sec
I got During the film formation, the molten metal contacted only the bottom surface of the crucible and not the side wall. When the obtained film was evaluated, oxidation was partially observed, but there was no abnormal inclusion which was a kind of contamination. From these, it was confirmed that the present invention is capable of sufficiently forming a film without pollution even in the air.

[0016]

As described above, according to the present invention, the vapor deposition material can be dissolved in the crucible in a state of being floated or raised. Therefore, contact between the raw material and the crucible can be minimized, and contamination of the deposited film can be suppressed. Further, by stirring the raw material, the components can be homogenized, and the obtained film can be homogenized. Further, since the vapor deposition can be performed even at a low pressure, no exhaust means is needed. In particular, since vapor deposition can be performed even in the atmosphere, cost reduction due to simplification of the device and uniformization of film thickness can be achieved. And because the raw material can be floated and melted,
A metal having a high melting point exceeding the heat resistant temperature of the refractory (about 1700 ° C.) can also be used as the vapor deposition material.

[Brief description of drawings]

FIG. 1 is a schematic view of a semi-floating PVD device of the present invention.

FIG. 2 is a schematic view of a floating type ion plating apparatus of the present invention.

[Explanation of symbols]

 1 Crucible 1A Sidewall 1B Bottom 2 Induction coil 3 Substrate holder 5 Crucible 6 Induction coil 7 Substrate holder 8 High frequency coil M Raw material M1 Liquid phase part M2 Solid phase part S Substrate

Claims (8)

[Claims] 1. A PV comprising a crucible having a cooling mechanism, a substrate holder located above the crucible, and an induction heating device provided on the outer periphery of the crucible.
D device. 2. A crucible having a cooling mechanism, a substrate holder located above the crucible, a high frequency coil for ionizing the vapor of the raw material generated by melting in the crucible in the middle of the crucible and the substrate, and an outer periphery of the crucible. An ion plating device comprising: an induction heating device provided. 3. The PVD apparatus according to claim 1, further comprising at least one of an atmosphere gas introduction mechanism, a vacuum evacuation mechanism and a pressurization mechanism. 4. The ion plating apparatus according to claim 2, comprising at least one of an atmosphere gas introducing mechanism, a vacuuming mechanism and a pressurizing mechanism. 5. A vapor deposition method in which a raw material is melted in a crucible and vapor generated is deposited on a substrate placed on the upper part of the crucible to form a film, wherein the raw material melted by induction heating is brought into non-contact with the side wall of the crucible. A vapor deposition method comprising forming a film in an atmosphere of 10 ⁻⁴ torr or more and less than 1 atm. 6. A vapor deposition method in which a raw material is melted in a crucible and the generated vapor is deposited on a substrate placed on the upper part of the crucible to form a film, wherein the raw material melted by induction heating is brought into non-contact with the side wall of the crucible. A vapor deposition method characterized by forming a film in an atmosphere of 1 atm or more. 7. A vapor deposition method in which a raw material is melted in a crucible to generate steam, the steam is ionized, and the steam is deposited on a substrate placed on the upper part of the crucible to form a film, which is melted by induction heating. A vapor deposition method, characterized in that the above-mentioned raw material is brought into non-contact with the side wall of the crucible and is formed in an atmosphere of 10 ^-4 torr or more and less than 1 atm. 8. A vapor deposition method in which a raw material is melted in a crucible to generate steam, the steam is ionized, and the steam is deposited on a substrate placed on the upper part of the crucible to form a film, which is melted by induction heating. A vapor deposition method, characterized in that the formed raw material is brought into non-contact with the side wall of the crucible and is formed in an atmosphere of 1 atm or more.