JP2008297596A - Ion plating method and ion plating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and uniformly perform the film deposition by realizing plasma of high density, uniformity and low pressure in the ion plating. <P>SOLUTION: A film deposition material 3 and a workpiece 13 on which a film is vapor-deposited are arranged opposite to each other in a vacuum chamber 1. Plasma P is generated in a space between the film deposition material and the workpiece. Plasma is confined by a line-cusp type magnetic field; the film deposition material is heated and evaporated, and the evaporated particles are ionized by plasma, and applied to the workpiece together with plasma to deposit the vapor-deposited film of the film deposition material on the workpiece. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ion plating method and apparatus for performing vacuum deposition in a plasma atmosphere.

  An ion plating apparatus is a film forming apparatus that combines an evaporation phenomenon in a vacuum atmosphere and a plasma generation technique, and is widely used in various fields. In these ion plating apparatuses, a film having a uniform composition and a uniform film thickness distribution is required to be formed efficiently in a short time. To meet this demand, many ion plates have been developed so far. Developed and put into practical use.

  As an example of such an ion plating apparatus, an object to be processed in which a vapor deposition film is formed in a vacuum chamber, a hearth for dissolving a film forming material provided below the vacuum chamber, and a gas inlet, A DC bias device that applies a DC bias to the object to be processed is connected to the workpiece. Further, an electron beam generator that supplies an electron beam toward the hearth, and an electron that is supplied from the electron beam generator are efficiently deposited. And a focusing coil that forms a magnetic field for ionizing the evaporated particles of the deposition material and the introduced gas, and swings the electron beam incident on the deposition material and evaporates the ions from the hearth. And a second focusing coil for guiding the ions and plasma of the introduced gas to the object to be processed while oscillating in synchronization with the electron beam (see Patent Document 1). .

  This apparatus tries to improve the non-uniformity of the film thickness distribution of the deposited film by oscillating the electron beam for heating and evaporating the film forming material, the ions of the film forming material, the ions of the introduced gas, and the plasma. However, there has been a problem that complicated device control is required.

In any of the conventional ion plating apparatuses including this apparatus, the confinement of the generated plasma is insufficient, and as a result, the plasma uniformity is poor and the plasma density is low. For this reason, in order to sufficiently ionize the evaporated particles of the film forming material, it is necessary to introduce a large amount of gas into the vacuum chamber to increase the pressure, and a high quality film with few impurities cannot be obtained.
Furthermore, in the conventional ion plating apparatus, only one electron source is used for heating the hearth, and the current value obtained from one electron source is limited. However, it was difficult to form a thick film.

JP-A-6-264225

  Accordingly, an object of the present invention is to efficiently and uniformly form a film by increasing the density, uniformity, and pressure of plasma in ion plating.

  In order to solve the above-described problem, the first invention provides a film-forming material and an object on which a vapor deposition film is to be formed facing each other in a vacuum atmosphere, and plasma is formed between the film-forming material and the object to be processed. The plasma is confined by a line cusp magnetic field, the film-forming material is heated and evaporated, the evaporated particles are ionized by the plasma, and the object to be processed is irradiated with the plasma. The ion plating method is characterized in that a deposited film of the film forming material is formed.

  In order to solve the above-mentioned problem, the second invention is the above-described film-forming material, wherein a film-forming material and an object to be vapor-deposited are disposed opposite to each other in a vacuum chamber that maintains a vacuum atmosphere therein. And generating plasma between the object to be processed, confining the plasma by a line cusp magnetic field, and holding the film-forming material at a positive potential with respect to the vacuum chamber, thereby generating electrons in the plasma. Inducing to the film material, heating and evaporating the film forming material by irradiation of the electrons, ionizing the evaporated particles by the plasma, and irradiating the object to be processed together with the plasma, to the object to be processed An ion plating method is characterized in that a vapor deposition film of a film forming material is formed.

  In order to solve the above-mentioned problem, the third invention provides a vacuum chamber, vacuum evacuation means connected to the vacuum chamber, and evaporation that is provided at the bottom of the vacuum chamber and that heats and evaporates while holding the film forming material. Provided in the vacuum chamber, and in the vacuum chamber, an object to be formed on which a vapor deposition film is to be formed, disposed opposite to the evaporation unit with a space therebetween. A workpiece supporting portion that supports the workpiece, a plasma generating portion that generates plasma in the vacuum chamber, a gas supply source that supplies a reactive gas to the plasma, and a space outside the vacuum chamber. A plurality of magnets that are arranged so that N poles and S poles are alternately arranged and generate a line cusp type magnetic field configuration for confining the plasma. The evaporated particles of the film forming material are ionized by the plasma confined by the line cusp type magnetic field, and the object to be processed is irradiated together with the plasma to form a vapor deposition film on the object to be processed. A characteristic ion plating apparatus is configured.

  In order to solve the above-mentioned problems, the fourth invention includes a vacuum chamber, vacuum evacuation means connected to the vacuum chamber, an evaporation container that is provided at the bottom of the vacuum chamber and holds a film forming material, An object to be deposited on which a vapor deposition film is to be formed, which is disposed in the vacuum chamber and is opposed to the evaporation container with a space above the evaporation container, and the object to be formed provided in the vacuum chamber. A workpiece support for supporting a workpiece, a plasma generator for generating plasma in the vacuum chamber, a gas supply source for supplying a reactive gas to the plasma, and spaced apart from each other outside the vacuum chamber; A plurality of magnets that are arranged so that N-poles and S-poles are alternately arranged, and generate a line cusp-type magnetic field configuration for confining the plasma, and the film-forming material held in the evaporation container includes: The vacuum chamber is held at a positive potential, whereby electrons in the plasma are guided to the film forming material, the film forming material is heated and evaporated by irradiation with the electrons, and the evaporated particles are The ion plating apparatus is characterized in that it is ionized by plasma and irradiated to the object to be processed together with the plasma to form a deposited film on the object to be processed.

  In the configuration of the fourth invention, the ion plating apparatus preferably includes a plurality of electron generation sources for supplying electrons to the plasma confined by the line cusp magnetic field, and the electron generation source further includes a heat source. It is preferable to consist of a cathode or a cold cathode.

According to the present invention, the plasma generated in the vacuum chamber is confined by the line cusp magnetic field, so that the loss of electrons on the inner wall surface of the vacuum chamber is strongly suppressed. As a result, the plasma density at the center of the vacuum chamber is reduced. Ascends and the distribution becomes uniform. Thereby, the vapor deposition film can be efficiently and uniformly formed on the workpiece.
Further, according to the present invention, the electrons in the plasma confined by the line cusp type magnetic field are guided to the film forming material, and the film forming material is heated and evaporated by irradiation of the electron flow. It can be evaporated by heating to ultra high temperature.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of an ion plating apparatus according to one embodiment of the present invention, (A) is a longitudinal sectional view, and (B) is taken along line AA ′ of (A). It is a cross section.
Referring to FIG. 1A, according to the present invention, a vacuum chamber 1 is provided. In this embodiment, the vacuum chamber 1 has a cylindrical shape with substantially closed openings at both ends, but the shape of the vacuum chamber 1 is not limited to this, for example, any shape such as a hollow rectangular parallelepiped. Can be.

A vacuum exhaust system 2 for maintaining the inside of the vacuum chamber 1 in a low pressure state (several Torr to 10 ⁻⁷ Torr) is connected to the lower peripheral wall of the vacuum chamber 1.
In the center of the bottom of the vacuum chamber 1, there is provided an evaporation section 4 that heats and evaporates the film forming material 3. In this embodiment, the evaporation section 4 has a conductive support leg 5 protruding from the bottom wall of the vacuum chamber 1 and a tungsten plate 6 electrically connected to the upper end of the support leg 5. Yes. The plate 6 has a circular recess 7 for accommodating the film forming material 3 in the center. The support leg 5 is fixed to the bottom wall of the vacuum chamber 1 via an insulator 8, and the plate 6 and the support leg 5 constitute one electric circuit. A power source 9 is connected to the support leg 5, whereby the plate 6 generates heat and the film forming material 3 is heated.

  A circular shielding plate 10 is disposed at a height position of the plate 6 in the vacuum chamber 1, and the internal space of the vacuum chamber 1 is partitioned into two. The shielding plate 10 is formed of an insulator, for example, and has a function of shielding plasma. A circular opening 11 corresponding to the recess 7 of the plate 6 is formed at the center of the shielding plate 10, and a ventilation gap 12 is formed between a part of the periphery of the shielding plate 10 and the vacuum chamber 1. ing.

  In the vacuum chamber 1, an object to be processed 13 on which a vapor deposition film is to be formed is disposed opposite to a position spaced above the recess 7 of the plate 6 of the evaporation unit 4. The workpiece 13 is supported by a conductive workpiece holder 14 provided on the upper wall of the vacuum chamber 1. The workpiece holder 14 is fixed to the upper wall of the vacuum chamber 1 through an insulator 15. The workpiece 13 is usually made of a conductor and is electrically connected to the workpiece holder 14.

  A discharge power source 16 is connected between the workpiece holder 14 and the wall of the vacuum chamber 1, and the workpiece holder 14, that is, the workpiece 13, is held at a negative potential. In this way, glow discharge is caused between the workpiece 13 and the wall of the vacuum chamber 1, whereby plasma P is generated in the space above the shielding plate 10 in the vacuum chamber 1. The plasma P is supplied with a reactive gas G from a gas supply source (not shown) through a gas inlet 18 formed in the peripheral wall of the vacuum chamber 1. The reaction gas is usually composed of a mixed gas of an inert gas such as helium or argon and a gas such as oxygen, nitrogen or methane. However, only the inert gas may be supplied depending on the processing method. .

  As shown in FIGS. 1A and 1B, a large number of elongated rectangular permanent magnets 19 are spaced apart from each other on the outer surface of the peripheral wall and the upper wall of the vacuum chamber 1 and have N and S poles. Are arranged alternately. Thus, by arranging a large number of permanent magnets 19 along the wall of the vacuum chamber 1, a line cusp magnetic field (multipolar magnetic field) localized on the wall surface can be formed. Then, by confining the plasma P with this magnetic field, it is possible to reduce the pressure, density, and uniformity of the plasma.

  The plasma P is confined as follows. As indicated by magnetic field lines 20 in FIG. 1B, a line cusp type magnetic field (multipolar magnetic field) is formed for each pair of N and S poles. The strength of this magnetic field suddenly weakens as it moves away from the surface of the magnet, and the magnetic field is concentrated within a short distance from the wall of the vacuum chamber 1, and most of the inside of the plasma P may be considered as no magnetic field. . In addition, this magnetic field acts on charged particles (electrons and ions) constituting the plasma and causes them to swivel.

When charged particles diffused from the center of the plasma P without a magnetic field reach the vicinity of the wall of the vacuum chamber 1, the following confinement effect is generated by the multipolar magnetic field there. That is, the charged particles that have traveled toward the multipolar magnetic field are reflected by the magnetic mirror effect and returned to the center. On the other hand, when the multipolar magnetic field is viewed from the center, the magnetic lines of force are directed in the radial direction only in the vicinity of the magnetic field, but many other portions are directed in the azimuth direction. Therefore, the charged particles about to flow out in the radial direction must cross the magnetic field lines almost perpendicularly, and the diffusion of the charged particles is strongly suppressed.
Due to the confinement of the plasma P, the loss of charged particles is strongly suppressed on the inner surface of the vacuum chamber 1, and as a result, the plasma density in the central portion increases and the distribution thereof is made uniform.

  Thus, the vaporized particles S of the film forming material 3 evaporated from the evaporation unit 4 are introduced into the plasma P confined by the line cusp magnetic field (multipolar magnetic field) and ionized, and the workpiece 13 is irradiated together with the plasma P. As a result, a high quality film having a constant film thickness distribution and almost no impurities is formed on the object 13 to be processed.

FIG. 2 is a longitudinal sectional view showing a schematic configuration of an ion plating apparatus according to another embodiment of the present invention. The embodiment of FIG. 2 differs from the embodiment of FIG. 1 only in the configuration for heating and evaporating the film forming material. Therefore, in FIG. 2, the same components as those shown in FIG.
With reference to FIG. 2, in this embodiment, an evaporation container 21 for holding the film forming material 3 is provided at the center of the bottom of the vacuum chamber 1. The evaporation container 21 is made of a high melting point conductor such as carbon. The evaporation container 21 is supported and fixed on the upper end of a conductive container holder 22 projecting from the bottom wall of the vacuum chamber 1, and is electrically connected to the container holder 22. The container holder 22 is fixed to the bottom wall of the vacuum chamber 1 via an insulator 24. A cylindrical member 23 made of an insulator projects from the bottom wall of the vacuum chamber 1 and surrounds the evaporation container 21 and the container holder 22.

An extraction power source 25 is connected between the wall of the vacuum chamber 1 and the container holder 22, and the film forming material held in the evaporation container 21 is held at a positive potential with respect to the vacuum chamber 1.
As a result, electrons in the plasma are guided to the film forming material, and the film forming material is heated and evaporated by being irradiated with the electron flow.

  According to this embodiment, a plurality of hot cathode filaments 26 are attached to the upper wall of the vacuum chamber 1. These hot cathode filaments 26 function as an electron generation source that supplies electrons to the plasma confined by the line cusp magnetic field.

Furthermore, a discharge power source 16 is connected between each hot cathode filament 26 and the wall of the vacuum chamber 1.
Thus, according to this embodiment, a glow discharge is caused between the hot cathode filament 26 and the wall of the vacuum chamber 1, thereby generating a plasma P in the space above the shielding plate 10 in the vacuum chamber 1. The The plasma P is supplied with a reactive gas G from a gas supply source (not shown) through a gas inlet 18 formed in the peripheral wall of the vacuum chamber 1. The reaction gas is usually composed of a mixed gas of an inert gas such as helium or argon and a gas such as oxygen, nitrogen or methane. However, only the inert gas may be supplied depending on the processing method. .
When the hot cathode filament 26 is sputtered by the plasma P, its constituent elements are vaporized and may become impurities of the film formed on the workpiece 13. Therefore, it is desirable to arrange the hot cathode filament 26 at a position where it cannot be directly seen from the workpiece 13.

  And since the film-forming material 3 held in the evaporation container 21 is held at a positive potential with respect to the vacuum chamber 1 by the extraction power supply 25, electrons in the plasma P are induced to the film-forming material 3, The film forming material is heated and evaporated by irradiation with the electron stream I, and the vaporized particles S are ionized by the plasma P and irradiated to the object 13 together with the plasma P, so that a film is formed on the object 13. .

  According to this embodiment, electrons in the plasma P confined by a line cusp type magnetic field (multipolar magnetic field) are guided to the film forming material 3, and the film forming material 3 is heated and evaporated by irradiation of the electron current I. Therefore, the film-forming material 3 can be evaporated by heating at a very high temperature in a short time. Further, since a plurality of electron generation sources (hot cathode filaments 26) are arranged to supply a large amount of electrons into the plasma P, the load per electron generation source is reduced, and the evaporation container 21 is provided. The density of the induced electron current I can be increased, whereby the film forming material 3 can be heated to a very high temperature at a high speed. Further, since the evaporated particles S of the film forming material 3 are introduced into the confined plasma P and ionized, and the object 13 is irradiated with the ions of the reaction gas, the film thickness distribution is constant, the impurities It is possible to form a high-quality film containing almost no N on the object to be processed in a short time. In addition, a film having a large thickness can be easily formed.

The structure of this invention is not limited to this Example, A various modification can be comprised within the range of the structure as described in a claim.
For example, in the above embodiment, a hot cathode filament is used as an electron generation source, but a cold cathode such as a hollow cathode may be used.
Moreover, the shape of the vacuum chamber is a box shape having a long rectangular cross section, and a plurality of evaporation containers are arranged in series, or by using an elongate evaporation container, a roll-shaped workpiece is continuously formed. It becomes possible to process.
In the above embodiment, the workpiece is held at room temperature by the workpiece holder. However, for the purpose of improving the film quality, a heater may be incorporated in the workpiece holder to heat the workpiece. .

In some cases, the film quality can be improved by controlling the kinetic energy of ions induced from the plasma to the object to be processed. In this case, a bias power source is connected between the object to be processed and the vacuum chamber. Connecting.
Further, when it is necessary to prevent deterioration of film quality due to the introduction of ions from the plasma to the object to be processed, it is preferable to generate a magnetic field for plasma shielding in the vicinity of the object to be processed.

When a reactive gas such as oxygen is used as the reactive gas, the consumption of the electron generation source becomes a problem. In this case, it is preferable to use a microwave or high frequency plasma generating means instead of the glow generating plasma generating means. Alternatively, a cathode plasma generation chamber may be provided in the vacuum chamber, microwaves or the like may be introduced into the cathode plasma generation chamber to generate plasma, and primary electrons may be introduced into the vacuum chamber.
When oxygen, nitrogen, or the like is used as a reaction gas, an insulating film is formed on the surface of the film forming material, and heating by an electron current may not be performed sufficiently. In that case, it is preferable to change the extraction power source to an AC power source or a high voltage pulse superimposed power source.

It is a figure which shows schematic structure of the ion plating apparatus by one Example of this invention, (A) is a longitudinal cross-sectional view, (B) is a cross-sectional view along the AA 'line of (A). is there. It is sectional drawing similar to FIG. 1 (A) which shows schematic structure of the ion plating apparatus by another Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Vacuum exhaust system 3 Film-forming material 4 Evaporating part 5 Support leg 6 Plate 7 Recessed part 8 Insulator 9 Power supply 10 Shielding plate 11 Opening 12 Venting gap 13 Processed object 14 Processed object holder 15 Insulator 16 For discharge Power source 18 Gas inlet 19 Permanent magnet 20 Magnetic field lines G Reactive gas P Plasma S Evaporated particles of film forming material

Claims (6)

  In a vacuum atmosphere, a film forming material and an object to be vapor-deposited are placed opposite to each other, and plasma is generated between the film forming material and the object to be processed and the plasma is confined by a line cusp magnetic field. The deposition material is heated and evaporated, the evaporated particles are ionized by the plasma, and the treatment object is irradiated with the plasma to form a vapor deposition film of the deposition material on the treatment object. An ion plating method characterized by the above.   In a vacuum chamber in which a vacuum atmosphere is maintained, a film forming material and an object to be vapor-deposited are disposed to face each other, and plasma is generated between the film forming material and the object to be processed. The plasma is confined by a line cusp magnetic field, and the film-forming material is held at a positive potential with respect to the vacuum chamber to induce electrons in the plasma to the film-forming material, and the film is formed by irradiation with the electrons. A vapor deposition film of the film forming material is formed on the object to be processed by heating and evaporating the material, ionizing the evaporated particles by the plasma, and irradiating the object with the plasma. Ion plating method. A vacuum chamber;
Evacuation means connected to the vacuum chamber;
An evaporation unit that is provided at the bottom of the vacuum chamber and that heats and evaporates while holding the film forming material;
An object to be processed in which a vapor deposition film is to be formed, which is disposed in the vacuum chamber so as to be opposed to the upper part of the evaporation unit at an interval;
A workpiece support portion provided in the vacuum chamber for supporting the workpiece;
A plasma generator for generating plasma in the vacuum chamber;
A gas supply source for supplying a reactive gas to the plasma;
A plurality of magnets arranged outside the vacuum chamber and spaced apart from each other and alternately arranged with N and S poles to generate a line cusp-type magnetic field configuration for confining the plasma,
The evaporated particles of the film forming material evaporated from the evaporation unit are ionized by the plasma confined by the line cusp magnetic field, and are irradiated onto the object to be processed together with the plasma, thereby forming a vapor deposition film on the object to be processed. An ion plating apparatus characterized by being a device. A vacuum chamber;
Evacuation means connected to the vacuum chamber;
An evaporation vessel that is provided at the bottom of the vacuum chamber and holds a film-forming material;
An object to be processed in which a vapor deposition film is to be formed, which is disposed in the vacuum chamber and is opposed to the evaporation container with an interval therebetween;
A workpiece support portion provided in the vacuum chamber for supporting the workpiece;
A plasma generator for generating plasma in the vacuum chamber;
A gas supply source for supplying a reactive gas to the plasma;
A plurality of magnets arranged on the outside of the vacuum chamber so as to be alternately arranged with N poles and S poles arranged alternately, and to generate a line cusp type magnetic field configuration for confining the plasma. The film forming material held in the container is held at a positive potential with respect to the vacuum chamber, whereby electrons in the plasma are guided to the film forming material, and the film forming material is irradiated with the electrons. The ion plating apparatus is characterized in that the evaporated particles are heated and evaporated, the vaporized particles are ionized by the plasma, and the object to be processed is irradiated with the plasma to form a vapor deposition film on the object to be processed. .   The ion plating apparatus according to claim 4, further comprising a plurality of electron generation sources that supply electrons to the plasma confined by the line cusp magnetic field.   6. The ion plating apparatus according to claim 5, wherein the electron generation source is a hot cathode or a cold cathode.

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