JPH0977597A - Apparatus for producing crystal oriented film and production of crystal oriented film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to efficiency and inexpensively produce triaxially oriented films useful for production of functional thin films, such as piezoelectric films, ferroelectric films and magnetic material thin films, for which crystal orientation is important, and thin films for buffer layers for epitaxially growing superconducting thin films, etc., on substrates, consisting of glass, ceramic, etc., even at a low temp. SOLUTION: This sputtering device is constituted by building a substrate electrode 3 to be mounted with a substrate 2, auxiliary electrodes consisting of plural sheets (n sheets) of rectangular electrode plates 4 between this substrate electrode 3 and a target 1 and plural sheets (n-1 sheets) of band-shaped masks 5 between the auxiliary electrodes and the substrate electrode 3. High-frequency voltage is impressed on the substrate electrode 3 and DC voltage is impressed on the rectangular electrodes 4 of the auxiliary electrodes, respectively, by which the crystal oriented film is formed on the substrate surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal orientation film production apparatus and a crystal orientation film production method using this apparatus. More specifically, the present invention accelerates a cation flow velocity in a uniform direction to obliquely enter when forming a film by sputtering using a sputtering apparatus,
Suitable for the production of functional thin films such as piezoelectric films, ferroelectric films, magnetic thin films, etc. where crystal orientation is important, and buffer film thin films for epitaxial growth of superconducting thin films on substrates of glass, ceramics, metals, etc. The present invention relates to a new crystal orientation film production apparatus capable of efficiently producing a triaxially oriented thin film or the like that can be used, at low cost, and a crystal orientation film production method using the same.

[0002]

2. Description of the Related Art With the recent advances in ultraprecision technology and ultrafine technology, functional thin film technology has made great strides. Such progress is supported by the development of control technology of the crystal orientation structure of a thin film as represented by so-called epitaxy technology. In the production of such a crystal orientation film, a polycrystalline material such as metal or ceramics or an amorphous material such as glass is used as a substrate, and a thin film is grown on the substrate while controlling the crystal orientation to obtain excellent electromagnetic properties. It is intended to provide a thin film having optical / mechanical / chemical properties and new functions.

However, conventionally, when an oriented film is manufactured on a substrate made of a polycrystalline body or an amorphous body, for example, a c-axis oriented polycrystalline film such as a c-axis oriented piezoelectric film of ZnO, AlN, or the like is used. As described above, the production of a thin film oriented only in the uniaxial direction is the main one, and it has been very difficult to produce a thin film oriented in the triaxial direction. Further, in order to obtain a thin film that is monoaxially triaxially oriented, a single crystal substrate is used instead of a polycrystal or amorphous body, and fine step processing is performed by an epitaxy technique or a patterning technique on the substrate surface. There is known a method of forming a single crystal film by a graphoepitaxy technique of growing a single crystal film by this method. In this method, a single crystal triaxially oriented thin film is formed on a polycrystalline or amorphous substrate. It was almost impossible to get it done.

Under such circumstances, in 1985, I
It is possible to control not only the c-axis but also the orientation in the ab plane by depositing an Nb thin film on a glass substrate by an ion assisted deposition method using a dual ion beam sputtering method using Yu of BM and the like. The first report suggesting sex was made (LSYU, et al: Appl. Phys. Lett. 47 (198
5) P. 932).

Next, in 1991, Fujikura's Iiji
It has been reported by MA et al. that YSZ (yttria-stabilized zirconia) thin films are triaxially oriented on a polycrystalline metal substrate by an ion beam assisted deposition method similar to the dual ion beam sputtering method (Y. Iijima ,
et al: Appl. Phys. Lett. 60 (1992) P. 76
9).

Furthermore, in 1992, Reade et al. Obtained similar results using an ion beam assisted gun for laser deposition. However, in the film forming methods shown in these reports, it is essential to use an expensive film forming apparatus such as a dual ion beam, and it is still easier to control the crystal orientation by a general-purpose device which is inexpensive. It was impossible.

Therefore, in order to overcome the drawbacks of the prior art, the inventors of the present invention have already proposed a new crystal orientation film manufacturing apparatus (for example, Japanese Patent Application No. 4-32).
2318, Japanese Patent Application No. 5-239512). In the newly proposed crystal orientation film manufacturing apparatus, an electrode with a characteristic structure is incorporated in the sputtering apparatus, and charged particle groups are allowed to grow on the film surface in the plasma space formed by the bias voltage applied to this electrode. It is possible to produce a triaxially oriented thin film on the surface of a polycrystalline or amorphous substrate by obliquely incident on the substrate.

With this apparatus, it is possible to obtain an oriented thin film having excellent characteristics easily and inexpensively without using a conventional expensive film forming apparatus. However, the subsequent studies have revealed that this new crystal orientation film manufacturing apparatus also has points to be further improved in order to make full use of its characteristics. This is because this crystal orientation film manufacturing device is smaller, simpler in shape, and cheaper than the conventional device using a dual ion beam or an ion beam assist gun, but it is still used in that device. This is because it has become clear that the structure of the existing electrodes can be improved in terms of downsizing of the device and improvement of film forming characteristics.

Therefore, in view of the background as described above, the present invention is a small, inexpensive, and versatile apparatus that does not use an expensive film forming apparatus such as a dual ion beam. Another object of the present invention is to provide a new crystal orientation film production apparatus and a method using the same, which can efficiently produce an axially oriented thin film on an insulating substrate such as an amorphous body.

[0010]

As a solution to the above-mentioned problems, the present invention provides a sputtering apparatus,
A substrate electrode for mounting a substrate parallel to a target, and a plurality of (n having long sides parallel to the substrate and short sides perpendicular to the substrate between the substrate electrode and the target) (n
Auxiliary electrodes made of rectangular electrode plates and a plurality of (n-1) strip-shaped masks are incorporated between the auxiliary electrodes and the substrate electrodes. High frequency voltage is applied to the substrate electrodes and direct current is applied to the auxiliary electrodes. A crystal orientation film manufacturing apparatus (claim 1), wherein a crystal orientation film from a target material is formed on a substrate surface by applying respective voltages.

The present invention also provides the above-mentioned device,
The strip-shaped mask is provided between the pair of adjacent two electrodes of the auxiliary electrode on each center line and above the upper end of the auxiliary electrode.
The auxiliary electrode is provided so as to be electrically insulated (claim 2), and the substrate electrode is provided with a moving mechanism for moving the target vertically and / or horizontally, and mounting the substrate. A variable mechanism capable of varying the area of the discharge surface serving as a surface is provided, and the auxiliary electrode is provided with a moving mechanism that moves the auxiliary electrode in the horizontal direction (claim 3). It is an aspect.

Furthermore, the present invention provides a method for producing a crystal orientation film, characterized in that the crystal orientation film is formed by sputtering using the above apparatus (claim 4), and as one of its aspects, during film formation. Then, the auxiliary electrode or the substrate electrode is horizontally moved by the horizontal movement mechanism by a distance of ½ of the auxiliary electrode interval to continue film formation.
And a method for producing a triaxially oriented thin film on the entire surface of the substrate (Claim 5), or a method in which the substrate is an insulator (Claim 6).
Etc. are also provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the crystal orientation film manufacturing apparatus of the present invention has a structure in which the electrode composed of the substrate electrode, the auxiliary electrode and the strip mask is incorporated in the sputtering apparatus. As the structure of the present invention, for example, the structure illustrated in FIGS. 1 and 2 can be used. FIG. 1 is a perspective view of a main part of the apparatus, and FIG. 2 is a front sectional view thereof.

For example, as illustrated in FIGS. 1 and 2, in the crystal orientation film manufacturing apparatus of the present invention, as the sputtering apparatus, the substrate electrode (3) for mounting the substrate (2) in parallel to the target (1) is used. ) And a plurality of (n) arranged between the substrate electrode (3) and the target (1).
Auxiliary electrodes made up of (4) rectangular electrode plates (4), and a plurality of (n-1) electrodes between the rectangular electrode plates (4) and the substrate electrodes (3).
And a strip-shaped mask (5).

Then, for example, the substrate electrode (3) is provided with a variable mechanism for varying the area of the discharge surface serving as the mounting surface of the substrate (2), and the shield (6) is provided as a part thereof. There is. Further, the substrate electrode (3) is provided with a moving mechanism for moving the substrate electrode in the vertical direction, the horizontal direction, or both directions, and the rectangular electrode plate (4) as the auxiliary electrode is also provided with the horizontal moving mechanism. There is.

Explaining in more detail, a plurality of rectangular electrode plates (4) are arranged above the sputter target (1) in parallel with each other at intervals (S) of, for example, about 15 to 20 mm, with respect to the target (1). The short sides are arranged vertically and the long sides are arranged horizontally, and the number of sheets is appropriately determined according to the area of the substrate (2), the size of the target (1), the spacing (S) between the electrode plates, and the like. I can decide. An auxiliary electrode is formed by a plurality of these rectangular electrodes (4).
A plurality of strip-shaped masks (5) are provided above the auxiliary electrode for each center line between the pair of adjacent two electrode pairs of the auxiliary electrode and on the rectangular electrode plate (4) of the auxiliary electrode. ), And is electrically insulated from the auxiliary electrode and installed, for example, about 3 mm above the upper end. Belt mask (5)
A substrate electrode (3) for mounting the substrate (2) is provided above the
The strip mask (5) is incorporated horizontally above the strip mask (5), for example, about 1 to 3 mm above the horizontal plane. By providing the substrate electrode (3) with an up-and-down moving mechanism, the distance between the substrate electrode (3) and the belt-shaped mask (5) can be arbitrarily adjusted. Further, a high frequency voltage and a DC voltage are applied to the substrate electrode (3) and the rectangular electrode plate (4) of the auxiliary electrode, respectively.

In the crystal orientation film manufacturing apparatus of the present invention having such a structure, for example, first, the area of the discharge surface of the substrate electrode is adjusted by the variable mechanism provided in the substrate electrode (3), and the adjusted discharge surface is adjusted. Attach the substrate (2) to. Then, high frequency power is applied to the substrate electrode (3) and direct current power is applied to the rectangular electrode plate (4) of the auxiliary electrode. Before starting film formation, the shutter between the substrate electrode (3) and the rectangular electrode plate (4) of the auxiliary electrode is closed, and the target (1) surface is cleaned by pre-sputtering. After that, the shutter is opened, and the substrate electrode (3) is moved by the vertical movement mechanism to be held at an arbitrary position above the strip mask (5),
Start film formation. After a certain period of time from the start of film formation, the substrate is relatively moved relative to both electrodes by a horizontal movement mechanism provided in the rectangular electrode plate (4) or the substrate electrode (3) of the auxiliary electrode to 1 / A The film is horizontally moved by a distance of 2 to continue film formation. By doing so, for example, a triaxially oriented thin film can be grown on the substrate surface.

When a thin film is grown on a substrate made of an insulator such as glass or ceramics, a DC voltage is not applied as an effective bias voltage to the substrate electrode (3), but when a high frequency voltage is applied, the insulator is not formed. A negative bias is excited on the substrate surface. This is because the flow of electrons and cations from the plasma due to ambipolar diffusion occurs on the surface of the insulating substrate (2) in contact with the discharge plasma when a high-frequency voltage is applied, but the mobility of the electron is higher, so the substrate (2 )
This is because the surface is in an electron-excessive state, and in the steady state, a negative bias that balances the inflowing electron amount and the ion amount per unit time is generated. The negative bias Vs generated on the surface of the substrate (2) at this time is

[0019]

[Equation 1]

Is given by Here, As is the area of the substrate (2) mounting surface of the substrate electrode (3) in contact with plasma,
Aw is the total area of the vacuum vessel wall of the sputtering apparatus. Therefore, if As is made smaller than Aw, an effective negative bias is generated in the substrate (2). Then, the negative bias causes the cation flow to be accelerated and incident on the film surface, whereby in-plane orientation occurs. Since this in-plane orientation is strongly influenced by the density of incident cations, an effective negative bias for controlling the incident cations must be generated on the substrate surface, and for that reason, the substrate (2) of the substrate electrode (3) is required. It is important to adjust the area of the discharge surface, which is the mounting surface.
Therefore, in the substrate electrode (3) in the device of the present invention,
It is equipped with a variable mechanism that can change the area of the discharge surface, which is the mounting surface, while the high-frequency voltage is being applied.

Further, the short side of the rectangular electrode plate (4) constituting the auxiliary electrode is, for example, about 15 to 25 mm, and the interval between the rectangular electrode plates (4) is set to about 15 to 20 mm, whereby the substrate electrode (3 ) And the rectangular electrode plate (4) of the auxiliary electrode, an electric field suitable for generating a high-density plasma in the plasma space and for obliquely aligning Ar ⁺ ions and the like for sputtering in one direction. A distribution can be formed.

Further, by setting the installation position of the strip mask (5) above the upper end of the rectangular electrode plate (4) of the auxiliary electrode by, for example, about 3 mm, Ar ⁺ ions are vertically incident on the surface of the substrate (2). It is possible to avoid film growth in a region where in-plane orientation does not occur. Further, by moving the rectangular electrode plate (4) or the substrate electrode (3) of the auxiliary electrode in parallel during the film formation, a good quality thin film can be grown over the entire surface of the substrate (2).

Of course, the dimensional numerical values in the above device configuration are not limited. These numerical conditions are naturally determined as appropriate depending on the types and sizes of the substrate (2) and the target (1). Hereinafter, examples will be shown, and embodiments of the present invention will be described in more detail. Of course, the present invention is not limited by the following examples.

[0024]

【Example】

Example 1 A triaxially oriented YSZ (yttria-stabilized zirconium) thin film was formed on a quartz glass substrate. The apparatus of FIGS. 1 and 2 was used. The substrate (2) on which a thin film is formed has dimensions of 0.5 × 40 × 40 mm (thickness × width × length)
It is attached to the substrate attachment surface of the electrode substrate (3) using the quartz glass of. The discharge surface of this board mounting surface is the shield plate (6)
The area was adjusted to 100φ. The auxiliary electrode has a structure in which four rectangular electrode plates (4) each having a size of 0.5 × 20 × 100 mm (thickness × horizontal × vertical) are arranged in a plane at intervals of 18 mm. The strip-shaped mask (5) is located on each center line between the rectangular electrode plates (4) having the dimensions of 0.5 × 4 × 100 mm (thickness × horizontal × vertical) as described above and 3 mm above the upper end thereof. In addition, three sheets are arranged in an electrically floating state via ceramics insulating glass. As the target (1), 100φ YSZ (yttria-stabilized zirconia) is used. Ar-2% O ₂ is used as the sputtering gas at a pressure of 2 × 10 ⁻³ Torr. Before forming the film, the substrate electrode (3) is kept closed while the shutter between the substrate electrode (3) and the rectangular electrode plate (4) is closed.
Is applied to the rectangular electrode plate (4), and the surface of the target (1) is cleaned by pre-sputtering. After that, the shutter is opened, the substrate electrode (3) is lowered by the vertical movement mechanism, and the distance between the substrate electrode (3) and the strip mask (5) is maintained at a position of 2 mm, and finally the substrate electrode (3). The distance between the substrate (2) and the target (1) mounted on the
Start film formation. At the time of this film formation, 1 is applied to the substrate electrode (3).
A high-frequency voltage of 3.56 MHz is 150 W, a negative bias DC voltage of -125 V is applied to the rectangular electrode plate (4) of the auxiliary electrode, and a high-frequency voltage of 250 W is applied to the YSZ target (1).
throw into. Two hours after the start of film formation, the rectangular electrode plate (4) of the auxiliary electrode is horizontally moved by the horizontal movement mechanism by 9 mm, which is 1/2 of the electrode interval of 18 mm, and film formation is continued for two hours.

The YSZ thin film thus formed on the quartz glass substrate (3) was cut into strips, and the cut pieces were subjected to X-ray θ-2θ scan, pole figure and φ-scan measurements. FIG. 3 shows the measurement result of the X-ray θ-2θ scan of the obtained YSZ thin film. Further, FIG. 4 shows the measurement results of the (111) pole figure of the obtained YSZ thin film. As is clear from these FIGS. 3 and 4 and the measurement results of φ-scan, it was confirmed that the formed YSZ thin film had c-axis (200) orientation and ab in-plane orientation on the entire surface of the substrate. Was done. (Example 2) A triaxially oriented YSZ thin film was formed on a borosilicate glass substrate.

Using the apparatus shown in FIGS. 1 and 2, a substrate (2) having a dimension of 0.5 × 40 × 40 mm (thickness × width × length) C
A YSZ thin film was formed on the substrate (2) made of borosilicate glass under the same film forming conditions and film forming method as in Example 1 except that borosilicate glass of code # 7059 manufactured by Orning was used. The YSZ thin film formed on the borosilicate glass substrate (2) was cut into strips, and the cut pieces were measured by X-ray θ-2θ scan, pole figure, and φ-scan. As a result, the obtained YSZ thin film was prepared as in Example 1.
It was confirmed that, like the YSZ thin film on the quartz glass substrate in, the c-axis (200) orientation and the a-b in-plane orientation were performed on the entire surface of the substrate. (Example 3) A triaxially oriented YSZ thin film was formed on an alumina substrate.

Example 1 except that the apparatus of FIGS. 1 and 2 was used and alumina (99.5%) having dimensions of 0.5 × 30 × 30 mm (thickness × width × length) was used as the substrate (3). The film was formed under the same film forming conditions and film forming method as described above. Thus, the YSZ thin film formed on the alumina substrate (2) is cut into strips, and the cut pieces are subjected to X-ray θ-2θ scan,
The pole figure and φ-scan were measured. As a result, the obtained YSZ thin films were the YSZ thin films obtained in Example 1 and Example 2.
As with the Z thin film, it was confirmed that the entire surface of the substrate was c-axis (200) oriented and ab in-plane oriented. That is,
A triaxially oriented YSZ thin film could be manufactured on an alumina substrate. Example 4 A triaxially oriented CeO ₂ thin film was formed on a quartz glass substrate.

A film was formed under the same film forming conditions and film forming method as in Example 1 except that CeO ₂ was used as a target using the apparatus shown in FIGS. 1 and 2. Thus, the CeO ₂ thin film formed on the quartz glass substrate (2) was cut into strips, and the cut pieces were measured by X-ray θ-2θ scan, pole figure, and φ-scan. FIG. 5 shows the obtained Ce
It shows the measurement result of (111) φ-scan of the O ₂ thin film. From this FIG. 5 and the measurement results of the X-ray θ-2θ scan and the pole figure, the obtained CeO ₂ thin film was c-axis (200) oriented on the entire surface of the substrate in the same manner as the YSZ thin film on the quartz glass substrate in Example 1. And ab plane orientation was confirmed. That is, a triaxially oriented CeO ₂ thin film could be manufactured on a quartz glass substrate.

[0029]

As described above in detail, the apparatus of the present invention has a unique orientational arrangement that does not depend on the preferential orientational orientation of film growth (Vravais empirical rule), and strongly aligns with the c-axis, and at the same time ab It is possible to obtain a monocrystalline thin film that is oriented in the plane, that is, is triaxially oriented, on the entire surface of the substrate. Furthermore, due to the ion irradiation effect, a thin film having good crystallinity can be obtained even under low temperature film forming conditions.

For example, when the oxide superconductor thin film is applied to a microwave device or the like, a large substrate can be obtained at low cost, and a low dielectric constant and isotropic polycrystal or There is a demand for a film forming technique capable of growing a good quality superconducting thin film having a high critical current density on an amorphous substrate. However, in the past, in general, when an oxide superconductor is vapor-deposited on a polycrystalline substrate, the uniaxial orientation in the c-axis direction can be achieved relatively easily by orienting it perpendicularly to the substrate. It is not easy to align both a and b on the substrate surface. As a result, the crystal axes are disordered in the plane of the substrate and grain boundaries with a large inclination are formed between the crystal grains, so that the critical current that can be passed through the film is suppressed to a low level.

One way of solving this problem is provided by the present invention. That is, a thin film such as a YSZ film capable of suppressing an interfacial reaction with a superconducting film is grown in advance by in-plane orientation as a buffer layer on a substrate such as glass or ceramics, and the superconducting film is epitaxially grown thereon. It is possible to solve by doing.
Further, according to the present invention, since a simple electrode structure is simply incorporated into an ordinary sputtering apparatus and use of an expensive ion gun, a high vacuum exhaust system or the like is not required, a thin film oriented in three axes with high efficiency, convenience and low cost can be obtained. Is far superior to the conventional film forming apparatus in that it can be manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts illustrating a crystal orientation film manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a front sectional view corresponding to FIG.

FIG. 3 is a diagram showing a measurement result of an X-ray θ-2θ scan of a YSZ thin film.

FIG. 4 is a diagram showing measurement results of a (111) pole figure of a YSZ thin film.

FIG. 5 is a diagram showing measurement results of (111) φ-scan of CeO ₂ thin film.

[Explanation of symbols]

 1 Target 2 Substrate 3 Substrate electrode 4 Rectangular electrode plate 5 Strip mask 6 Shield

Claims (6)

[Claims] 1. In a sputtering apparatus, a substrate electrode for mounting a substrate parallel to a target and a long side parallel to the substrate and a short side perpendicular to the substrate electrode and the target are arranged. A plurality of (n) auxiliary electrodes made up of (n) rectangular electrode plates, and a plurality of (n-1) band-shaped masks are incorporated between the auxiliary electrodes and the substrate electrode,
A high-frequency voltage is applied to the substrate electrode and a direct current voltage is applied to the auxiliary electrode to form a crystal orientation film from the target material on the surface of the substrate. 2. The device according to claim 1, wherein the strip-shaped mask is electrically connected to the auxiliary electrode at every center line between the pair of adjacent two electrodes of the auxiliary electrode and above the upper end of the auxiliary electrode. An apparatus for producing a crystallographic orientation film, characterized in that the crystal orientation film is disposed so as to be electrically insulated. 3. The apparatus according to claim 1, wherein the substrate electrode has a moving mechanism that moves the target vertically or horizontally, or in both directions, and an area of a discharge surface serving as a mounting surface of the substrate is variable. The crystal orientation film manufacturing apparatus is provided with a variable mechanism capable of moving the auxiliary electrode, and a moving mechanism for moving the auxiliary electrode in a horizontal direction with respect to the target. 4. A method for producing a crystal orientation film, which comprises depositing the crystal orientation film by sputtering using the apparatus according to claim 1. 5. The method according to claim 4, wherein during the film formation, the auxiliary electrode is horizontally moved by a moving mechanism by a distance of ½ of the auxiliary electrode interval to continue the film formation.
A method for producing a crystal orientation film, which comprises producing a triaxially oriented thin film of b and c on the entire surface of the substrate. 6. The method for producing a crystal orientation film according to claim 4, wherein the film is formed on an insulating substrate.