JPH0665734A - Thin film forming device - Google Patents

Abstract

PURPOSE:To provide the thin film forming device by sputtering which can form films to a large area. CONSTITUTION:An anode electrode 2 and cathode electrode 5 constituting electrodes for discharge are disposed within a reaction vessel 1. The anode electrode 2 has a ladder-like structure constituted of wires having a circular section. A target 4 is fixed to the cathode electrode 2 and the anode electrode 2 is disposed between the target 4 and a substrate 3 to be formed with the thin film. A coil 100 for generating a magnetic field is disposed around the reaction vessel 1 to generate the magnetic field in the direction orthogonal with the electric field generated between the electrodes 2 and 5 for discharge. The power source 101 of the coil 100 is an AC power source. Since the ladder type anode 2 is adopted for this thin film forming device, the intensity of the magnetic field around the electrodes increases and plasma is more easily generated. The direction of the ions moving from the anode to the cathode is shifted by the magnetic field of the coil 100, by which the deposition of the sputtered particles on the substrate surface is uniformalized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a thin film used for solar cells, electrophotographic photoreceptors, photosensors, liquid crystal displays, optical films, ornaments and the like.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional thin film manufacturing apparatus. In FIG. 7, a first electrode (anode) 02, a substrate 03 to which a thin film is to be attached, a thin film material target 04, and a second electrode (cathode) 05 are installed in an airtight reaction container 01. ing.

The first electrode 02 is connected to the first power cable 06.
Is electrically connected to the ground 07 and grounded. The second electrode 05 is electrically connected to the high frequency power supply 09 via the second power cable 08. Also,
The high frequency power supply 09 is connected to the ground 07 via the third power cable 010. The second electrode 05 is electrically insulated from the reaction vessel 01 by the insulator 011.

Further, the second electrode 05 is cooled by a cooling water supply controller 012 and a cooling engine 013 in order to prevent the temperature from rising. In order to make the inside of the reaction container 01 a vacuum, the vacuum pump 014 sucks the gas in the reaction container 01 through the first valve 015 and discharges the gas.

On the other hand, argon gas (Ar) is supplied from the Ar gas supply source 018 through the second valve 016 and the flow rate controller 017 as the plasma generating gas into the reaction vessel 01. The pressure inside the reaction container 01 is measured by a vacuum gauge 019.

Using the device shown in FIG. 7, for example, Zn
The case of manufacturing an O 2 thin film will be described. First electrode 0
The substrate 03 is placed on the substrate 2, and the ZnO sintered body is fixed to the second electrode 05 as the target 04. In addition, the ZnO sintered body is obtained by calcining ZnO powder at 800 to 850 ° C. for about 1 hour, and then press-molding it into a required mold at a pressure of about 100 kg / cm ² .
It is manufactured by firing at about 930 ° C. for about 2 hours.

A second valve 016, a flow rate controller 017, and an Ar gas supply source 018 are introduced into the reaction vessel 01, and a vacuum pump 014 and a first valve 015 are used to introduce the inside of the reaction vessel 01. Set the pressure to about 0.01 Torr. On the other hand, the first and second electrodes 02, 05 are connected via the high frequency power supply 09, the second and third cables 08, 010.
Apply a high frequency voltage to.

Then, the Ar gas becomes a glow discharge plasma, and a large number of Ar ⁺ existing therein are accelerated toward the second electrode 05 and collide with the target 04. The target 04 is sputtered by the collision of Ar ⁺ , and the sputtered particles are deposited on the substrate 03 installed on the first electrode 02. Note that glass, quartz, sapphire, or the like is used as the material of the substrate 03.

[0009]

Since the substrate 03 on which the thin film is formed is placed on the electrode 02 as described above,
The size of the substrate 03 processed at one time is limited by the size of the electrode 02.

Further, since the high frequency power source 09 has a high frequency (for example, 13.56 MHz), most of the current flows on the surface (within about 0.01 mm depth) due to the skin effect due to the high frequency, so that the electric resistance increases. , The plasma is not uniform except in the central part of the electrode.

Therefore, even if the electrode area is increased,
The area that can be uniformly formed by sputtering is about 50 cm in diameter. As described above, it has been extremely difficult to form a large-area film in the past, and it could not be realized in practice. Under such circumstances, it is an object of the present invention to provide a thin film forming apparatus capable of forming a large area film.

[0012]

According to the present invention, in order to solve the above-mentioned problems, a discharge electrode is composed of a ladder-shaped anode and a flat-plate-shaped cathode assembled from a plurality of wires having a circular cross section, The sputtering target material is fixed to the surface of the flat plate-shaped cathode, and the substrate is arranged at a position where the ladder-shaped electrode is sandwiched between the target material and the substrate.

Further, in order to solve the above-mentioned problems, the present invention provides a coil for enclosing a reaction vessel and generating a magnetic field in a direction orthogonal to an electric field working between discharge electrodes, in addition to the above-mentioned configuration. A configuration having a power supply that supplies alternating current is also adopted.

[0014]

As described above, in the present invention, as the discharge electrode, a ladder-shaped anode electrode formed by assembling a plurality of wire rods having a circular cross-section is used instead of the conventional flat plate-shaped anode electrode. The electric field is relatively strong, and plasma is easily generated.

Further, in the present invention, a structure is adopted in which a magnetic field is applied in a direction orthogonal to the electric field direction between the discharge electrodes, and the magnetic field direction is alternately changed between positive and negative. It became possible to swing the flight direction of the ions moving from the anode to the cathode. as a result,
It is possible to uniformly average the deposition rate distribution of sputtered particles scattered by the sputtering phenomenon on the substrate surface.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in FIGS. In FIG. 1, reference numeral 1 is a reaction vessel having a degree of vacuum of about 1 × 10 ⁻⁸ Torr. Two
Is an anode electrode, has a ladder-like structure composed of a wire having a circular cross section as shown in FIGS. 3 and 4, and is used in combination with a cathode electrode 5 described later.

Reference numeral 3 denotes a substrate, which is a target material such as ZnO.
Thin film should be attached. Reference numeral 4 denotes a target, which is the material of the above-mentioned thin film, which is manufactured in the same manner as the conventional one. Reference numeral 5 denotes a cathode electrode, which is installed so as to face the electrode 2.

The cathode electrode 5 is cooled by a cooling pipe 13 and a cooling water supply controller 12 in order to prevent the temperature from rising. A first power cable 6 is electrically connected to the ground 7, and when used in combination with the second power cable 8 and the third power cable 10, the power of a high frequency power source 9 described later is applied to the electrodes 2 and 3. Supply to 5.

Reference numeral 9 is a high frequency power source, for example, a frequency of 13.5.
This is a 6 MHz power supply for sputtering. 11a and 11
Reference numeral b denotes first and second insulators, which ensure the airtightness of the electrode 5 and the first power cable and the reaction vessel 1, respectively, and electrically insulate them.

Reference numeral 14 denotes a vacuum pump, which sucks and discharges the gas in the reaction vessel 1 through the first valve 15. 18
Is an Ar gas supply source, the flow rate regulator 17 and the second valve 1
Ar gas is supplied to the reaction vessel 1 via 6.

A vacuum gauge 19 measures and displays the pressure in the reaction vessel 1. Reference numeral 100 denotes a magnetic field generating coil, which is installed so as to surround the reaction container 1 as shown in FIG. Reference numeral 101 denotes a magnetic field generation power supply, which supplies electric power to the coil 100 to generate a maximum magnetic field of about 120 gauss.

In the apparatus described above, the vacuum pump 1
4 is driven, the first valve 15 is opened to evacuate the inside of the reaction vessel 1, and the degree of vacuum is set to about 1 × 10 ⁻⁸ Torr. And
Ar gas supply source 18, flow rate regulator 17 and second valve 1
6 is used to supply Ar gas into the reaction vessel 1 and the pressure is set to about 0.01 Torr.

Next, to the anode electrode 2 and the cathode electrode 5 via the first, second and third cables 6, 8 and 10,
Electric power is supplied from the high frequency power source 9. When the voltage is gradually increased, Ar gas becomes glow discharge plasma, and a large number of Ar ⁺ ions are generated.

On the other hand, an AC power of, for example, 10 Hz is applied to the coil 100 by using a power source 101 to generate a magnetic field B in a direction orthogonal to the electric field E generated between the electrodes 2 and 5. The strength of the magnetic field is about 120 gauss at maximum.

A target 4 is placed between the electrodes 2 and 5.
Is installed, the behavior of the plasma generated during that time is as shown in FIG. That is, the electric field E
Is a direction perpendicular to the plane of the electrode 5 and the magnetic field B is generated in a direction perpendicular to the plane, so that the weighted particles such as Ar ⁺ ions and electrons existing between the two electrodes have (electric field) E ×
(Magnetic field) B drift acts.

Therefore, the Ar ⁺ ion is shown in FIG.
The target 4 is collided with the movement as shown by the dotted line and the alternate long and short dash line. As a result, due to the sputtering phenomenon, the target 4 has fine particles (called sputter particles).
And then scatter. Most of the sputtered particles reach the substrate 3 and form a film of the same material as the target.

In the above apparatus, the anode electrode 2 has a circular cross section and a diameter of, for example, 5 to 10 mm, and the radius of curvature is significantly smaller than that of the flat cathode 5 of the counter electrode. The strength of the electric field generated during the period is locally increased. Further, since a magnetic field is applied, plasma can be easily generated. Therefore, as shown in FIG. 6, it is possible to uniformly form a film over a large area as compared with the conventional apparatus.

Although the embodiment of the apparatus according to the present invention has been described above, it is needless to say that the present invention is not limited to this embodiment and various modifications may be made within the scope of the present invention. For example, in the above example, an inert Ar gas is used as a gas to be introduced into the reaction vessel. As this gas, an inert gas to which a reaction gas such as O ₂ or H ₂ is added, or a reaction gas Needless to say, even in the case of only the above, the above-mentioned embodiment can be similarly implemented.

[0029]

As described above in detail, in the device according to the present invention, the discharge electrode is constituted by the ladder-shaped anode and the flat-plate-shaped cathode which are assembled by a plurality of wires having a circular cross section. The surrounding electric field becomes strong and plasma is easily generated. As a result, it is possible to form a film uniformly on a substrate having a large area as compared with the conventional apparatus.

In addition to this, the reaction vessel is surrounded by
In the case where an alternating current is supplied to a coil that generates a magnetic field in a direction orthogonal to the electric field that acts between the discharge electrodes, the direction of ions moving from the anode to the cathode is swung, so that sputtered particles on the substrate surface Can be made uniform.

As described above, according to the device of the present invention, the industrial value in the field of manufacturing thin films such as amorphous silicon solar cells, thin film transistors, and optical sensors is extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which coils for generating a magnetic field are arranged around a reaction container.

FIG. 3 is a plan view of a ladder-shaped cathode electrode used in the device according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV of the ladder-shaped cathode electrode shown in FIG.

FIG. 5 is an explanatory view showing the operation of the present invention.

FIG. 6 ZnO deposited by the apparatus according to the present invention and the conventional apparatus
The figure which shows the film thickness distribution of a film.

FIG. 7 is a cross-sectional view showing the configuration of a conventional film forming apparatus.

[Explanation of symbols]

 1 Reaction Container 2 Anode Electrode 3 Substrate 4 Target 5 Cathode Electrode 9 High Frequency Power Supply 18 Ar Gas Supply Source 100 Magnetic Field Generation Coil 101 Magnetic Field Generation Power Supply

Claims (2)

[Claims] 1. A reaction vessel, means for introducing gas into the reaction vessel, means for discharging gas from the reaction vessel, discharge electrode housed in the reaction vessel, and discharge electrode. A thin film forming apparatus by sputtering the target material on the surface of a substrate installed in the reaction container, the discharge electrode having a power supply for supplying power to the target material and a sputtering target material housed in the reaction container. However, the cross section is constituted by a ladder-shaped anode and a flat-plate type cathode assembled by a plurality of circular wire rods, the target material is fixed to the flat-plate type cathode surface, and the ladder-shaped electrode. A thin film forming apparatus characterized in that a substrate is arranged at a position sandwiched between the target material and the substrate. 2. A coil which surrounds the reaction vessel and generates a magnetic field in a direction orthogonal to an electric field working between the discharge electrodes,
The thin film forming apparatus according to claim 1, further comprising a power supply for supplying an alternating current to the coil.