JPH1112725A - Coating method of metal oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method capable of coating a metal oxide having uniform variance of specific resistance inside a face of a large area substrate. SOLUTION: Plural plasma guns 1A, 1B having a magnet means consisting of annular permanent magnets 21a, 21b and electromagnet coils 22a, 22b are arranged in a vacuum container 11. Convergent coils 24a, 24b and hearthes 30a, 30b as an anode accommodating an evaporated substance corresponding to respective plasma gun are arranged in each plasma gun. Around each heath, the annular permanent magnets and the electromagnet are arranged, directions of respective magnet pole of the magnet means of plural plasma guns, the convergent coils, the annular permanent magnets and the electromagnet coils are made reverse at each corresponding element of an adjacent plasma gun, thus, film coating is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a uniform metal film on a substrate having a large area with good reproducibility by using a plurality of arc discharge plasma beams obtained by a discharge plasma generating means such as a composite cathode type plasma gun. In particular, the present invention relates to a method for coating a metal oxide to obtain a low-resistance transparent conductive film, a silicon oxide film having a high alkali barrier effect, or a magnesium oxide film having a high insulating property.

[0002]

2. Description of the Related Art As a transparent conductive film formed on a color filter substrate for a liquid crystal display, an ITO (indium-tin oxide) film is excellent. In addition, I
A TO film is formed as a conductive film. Conventionally, as a method of forming such an ITO film, a vacuum deposition method, a sputtering method,
An RF (high frequency) ion plating method and the like are known. In any method, when forming an ITO film on a glass substrate or a resin substrate with a color filter,
If the substrate temperature is set to 250 ° C. or higher, the color filter and the resin may be carbonized, boiled, cracked, etc.
Do not exceed ℃.

[0003]

By the way, in a color liquid crystal display, it is required to reduce the thickness of a transparent electrode from the viewpoint of high resolution and high transmittance. Also,
From the viewpoint of increasing the size and increasing the response speed, there is a demand for a low-resistance and uniform film formation of the transparent electrode on a large-area substrate.

However, in the case of the ITO film formed by the conventional apparatus or the film forming method, the substrate temperature during the formation process is limited to 250 ° C. or less for the above-mentioned reason, so that the reaction between indium and oxygen on the substrate is not performed. And crystallization is not sufficiently performed. As a result, a film having a small crystal grain size and many defects is formed. Since the defects capture carriers, the carrier electron concentration in the film is reduced, and an ITO film having a specific resistance required for a color liquid crystal display cannot be obtained. This produces a high performance color liquid crystal display. It was an obstacle to meeting.

On the other hand, by using an ion plating apparatus as shown in FIG. 3, specific resistance is 1.5 × 10 ^-4.
It became possible to obtain an Ω · cm ITO film. Hereinafter, the ion plating apparatus of FIG.
The film forming conditions under which an ITO film of × 10 ⁻⁴ Ω · cm was obtained will be described. The pressure gradient plasma gun 101 has a cathode 102 and first and second intermediate electrodes 103 and 104. The first intermediate electrode 103 has a built-in annular permanent magnet, and the second intermediate electrode 104 has a built-in electromagnetic coil. Reference numeral 105 denotes a converging coil, 106 denotes a vacuum vessel, 107 denotes a substrate to be processed, 108 denotes a hearth serving as an anode, 109 denotes an annular permanent magnet, and 110 denotes an electromagnetic coil.

Here, the magnetic poles of the plasma gun 101, the focusing coil 105, the annular permanent magnet 109, and the electromagnetic coil 110 will be described with reference to FIG. Note that the side of the electromagnetic coil from which the line of magnetic force exits from the center of the coil is referred to as an N pole.

The second intermediate electrode 1 of the first intermediate electrode 103
The 04 side is an “S pole”, and the second intermediate electrode 104 and the first intermediate electrode 103 side of the focusing coil 105 are an “S pole”. The upper side of the annular permanent magnet 109 and the electromagnetic coil 110 is the “S pole”. Such a type is called an S type. On the other hand, the type in which each magnetic pole of the first intermediate electrode 103, the second intermediate electrode 104, the converging coil 105, and the annular permanent magnet 109 is completely opposite to the S type described above is called an N type.

When an ITO film is formed by using an ion plating apparatus having a pair of a cathode and an anode as shown in FIG.
Although a TO film can be obtained, it is difficult to form an ITO film having a uniform specific resistance on a large-area substrate because it is one plasma beam.

It is an object of the present invention to provide a coating method capable of coating a large-area substrate with a metal oxide having a uniform in-plane variation in specific resistance.

[0010]

According to the present invention, a plurality of plasma guns having magnet means, a focusing coil provided in each plasma gun, and an evaporating material corresponding to each plasma gun are provided in a vacuum vessel. An ion plating apparatus provided with a hearth as an anode containing
An annular permanent magnet and an electromagnet are provided around the hearth, and the magnet means of the plurality of plasma guns, the focusing coil, and the orientation of each magnetic pole of the annular permanent magnet and the electromagnet correspond to each other of the adjacent plasma guns. A method for coating a metal oxide is provided, wherein the substrate is uniformly coated with the metal oxide in a reverse direction for each element.

The metal oxide is indium oxide to which tin oxide is added, or silicon oxide or magnesium oxide.

In the present invention, in the case of an ITO transparent conductive film made of indium oxide to which tin oxide is added, the in-plane variation of the specific resistance of the film coated on the substrate is within ± 7%. .

Further, according to the present invention, a silicon oxide film having an alkali elution amount of 0.3 μg / cm ² or less can be obtained on a substrate.

Further, according to the present invention, (111) of the X-ray diffraction spectrum of the magnesium oxide film coated on the substrate
A magnesium oxide film in which the peak intensity of the diffraction peak from the surface is 50% or more of the sum of the other peak intensities can be obtained on the substrate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described for an ion plating apparatus for forming a metal oxide film on a substrate. This embodiment shows an example in which two plasma guns 1 </ b> A and 1 </ b> B are provided in the vacuum chamber 11 of the film forming unit. Plasma gun 1 with reference to FIGS.
The configuration of B will be described. A pressure gradient type plasma gun 1B is provided on the cylindrical portion 12b provided on the side wall of the vacuum vessel 11.
Is installed. The plasma gun 1B includes a glass tube 15b whose one end is closed by a cathode 14b. In the glass tube 15b, an annular disk 16 made of LaB ₆ is used.
b, a cylinder 18b of molybdenum Mo having a built-in pipe 17b of tantalum Ta is fixed to the cathode 14b. The pipe 17b is for introducing a carrier gas 18 made of an inert gas such as argon into the plasma gun 1B.

The first and second intermediate electrodes 1 are provided between the end of the glass tube 15b opposite to the cathode 14b and the cylindrical portion 12b.
9b and 20b are arranged concentrically. An annular permanent magnet 21b for converging the plasma beam is built in the first intermediate electrode (acting as a first grid) 19b. An electromagnetic coil 22b for converging the plasma beam is built in the second intermediate electrode 20b (acting as a second grid). This electromagnetic coil 22
b is supplied from a power supply 23b.

The cylindrical portion 12 on which the plasma gun 1B is mounted
A focusing coil 24b that guides the plasma beam into the vacuum chamber 11 is provided around b. This focusing coil 2
4b is excited by a converging coil power supply 25b. A variable voltage type main power supply 28b is connected between the cathode 14b and the first and second intermediate electrodes 19b and 20b via drooping resistors 26b and 27b, respectively.

At the bottom inside the vacuum vessel 11, a hearth 3
0b, a ring-shaped auxiliary electrode 31b and a ring-shaped electromagnetic coil 36b disposed therearound. Hearth 30b
Has a recess into which the plasma beam from the plasma gun 1B is incident, and contains an evaporating substance such as an ITO tablet.

The hearth 30b and the auxiliary electrode 31b are made of a conductive material having good thermal conductivity, for example, copper. The auxiliary electrode 31b is attached to the hearth 30b via an insulator. The hearth 30b and the auxiliary electrode 31b are connected via a resistor 48b. Hearth 30b is connected to the positive side of main power supply 28b.
Therefore, the hearth 30b forms an anode from which the plasma beam is sucked into the plasma gun 1B.

An annular permanent magnet 35b is provided in the auxiliary electrode 31b.
And the electromagnetic coil 36b are accommodated, and the auxiliary electrode power supply 38b
Powered by The annular permanent magnet 35b is configured to be in the same direction as the magnetic field in the excited electromagnetic coil 36b. The auxiliary electrode power supply 38b is a variable power supply, and can change the current supplied to the electromagnetic coil 36b by changing the voltage.

A substrate holder 42 for holding a substrate 41 is provided inside the vacuum vessel 11. The substrate holder 42 is provided with a heater 43. Heater 4
3 is supplied with power from a heater power supply 44. Substrate holder 4
2 is electrically insulated and supported with respect to the vacuum vessel 11. A bias power supply 45 is connected between the vacuum vessel 11 and the substrate holder 42. As a result, the substrate holder 42 is biased to a negative potential with respect to the vacuum vessel 11 connected to the zero potential.

In the case of batch processing, the substrate 41 is held stationary in the vacuum chamber 11 by the substrate holder 42 during film formation, as shown in the figure. On the other hand, in the case of continuous processing,
A transfer chamber is formed in the upper space of the vacuum vessel 11, and a substrate holder on which a plurality of substrates can be mounted is mounted in the transfer chamber.
Continuous processing is performed by forming a film on a substrate moving at a very low speed while being movable from one side to the other side.

The auxiliary electrode 31b is an electrode switch 4
6b, it is connected to the positive side of the main power supply 28b. A drooping resistor 29b and an auxiliary discharge power supply 47b are connected to the main power supply 28b in parallel via a switch S1b.

In this ion plating apparatus, argon gas is introduced as a carrier gas through the cathode 14b of the plasma gun 1B. And vacuum container 1
A discharge occurs between the hearth 30b and the hearth 30b, thereby generating a plasma beam. This plasma beam is focused on the converging coil 24b and the annular permanent magnet 35b in the auxiliary electrode 31b.
And the magnetic field determined by the electromagnetic coil 36b and reaches the hearth 30b. I stored in Haas 30b
The TO sintered body is heated by the plasma beam and evaporates. These evaporated particles are ionized by the plasma beam, and a film is formed on the substrate 41.

The same applies to the plasma gun 1A, so that the description is omitted.

In such an ion plating apparatus, adjacent plasma beams are formed as shown in FIG. 1 in order to form a film having a specific resistance in-plane variation of ± 7% on a large-area substrate. The cathode and anode fields must be opposite to each other. The reason for this is that the interference between the magnetic flux lines of the respective converging coils, the annular permanent magnet in the auxiliary electrode, and the electromagnetic coil is reduced, and the twist of each plasma beam is reduced. In addition, if one a side in FIG. 1 is the S type as described in FIG. 4, the other b side must be the N type, and if the a side is the N type, the b side is the S type.
Must be of type

Next, specific examples and comparative examples will be described.

[Example 1] Conditions Plasma excitation mechanism: a side S type, b side N type Tablet: ITO sintered body to which 5 wt% of SnO ₂ is added Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm Soda-lime glass substrate with color filter Pressure during film formation: 2.0 × 10 ⁻³ Torr Oxygen partial pressure: 0.6 × 10 ⁻³ Torr Specific resistance distribution: 1.4 in 950 mm × 600 mm
× 10 ⁻⁴ Ω · cm, in-plane variation within ± 7% [Example 2] Conditions Plasma excitation mechanism: a-side N-type, b-side S-type Tablet: Sintered ITO with 5 wt% of SnO ₂ added Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate with color filter Pressure during film formation: 2.0 × 10 ⁻³ Torr Oxygen partial pressure: 0.6 × 10 ⁻³ Torr Specific resistance distribution: 950 mm × 1.3 within 600 mm
× 10 ⁻⁴ Ω · cm, in-plane variation within ± 7% [Comparative Example 1] Condition Plasma excitation mechanism: a-side N-type, b-side N-type Tablet: ITO sintered body to which 5 wt% of SnO ₂ was added Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate with color filter Pressure during film formation: 2.0 × 10 ⁻³ Torr Oxygen partial pressure: 0.6 × 10 ⁻³ Torr Specific resistance distribution: 1.5 in 950 mm x 600 mm
× 10 ⁻⁴ Ω · cm, in-plane variation within ± 12% [Comparative Example 2] Conditions Plasma excitation mechanism: a-side S-type, b-side S-type Tablet: Sintered ITO with 5 wt% of SnO ₂ added Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate with color filter Pressure during film formation: 2.0 × 10 ⁻³ Torr Oxygen partial pressure: 0.6 × 10 ⁻³ Torr Specific resistance distribution: 950 mm × 1.6 within 600 mm
× 10 ⁻⁴ Ω · cm, in-plane variation within ± 15% According to the first and second embodiments described above, the vacuum vessel has a plurality of plasma beam generation units, and is used to generate adjacent plasma beams. By inverting the magnetic poles of the magnetic field means, the focusing coil, the ring-shaped permanent magnet on the Haas side, and the magnetic pole of the electromagnetic coil, it is possible to eliminate magnetic field interference and to form an ITO transparent conductive film with low specific resistance on a large-area substrate. It became. Therefore, it is very effective when applied to a large-sized color liquid crystal display or the like which requires a high-speed response. Similarly, by reversing the adjacent magnetic field,
When two or more plasma beam excitation mechanisms are used, an ITO having a more uniform resistivity distribution on a substrate having a larger area
It is possible to obtain a film.

The following Table 1 shows Examples 1 and 2, Comparative Example 1,
2 shows the measurement results.

[0030]

[Table 1]

Next, an embodiment in which a SiO ₂ film is formed,
A comparative example is shown.

Example 3 Conditions Plasma excitation mechanism: a-side S type, b-side N type Tablet: SiO ₂ tablet Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm Soda lime glass substrate pressure during film formation : 5.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr Alkali elution amount: 0.25 μg / cm ² or less in 950 mm × 600 mm Film formation rate: 50 A / sec [Example 4] Conditions Plasma excitation mechanism: a-side N-type, b-side S-type Tablet: SiO ₂ tablet Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 5.0 × 10 ⁻⁴ Torr oxygen partial pressure: 1.0 × 10 ^-4 Torr alkali elution amount: 0.10 .mu.g / cm ² or less at 950 mm × 600 mm in Film speed: 50 Å / sec Comparative Example 3 conditions plasma excitation mechanism: a side N-type b-side N-type tablet: SiO ₂ Tablet substrate temperature: 200 ° C. discharge current: Each 150A board: 1000 mm × 650 mm soda lime glass substrate formed In-film pressure: 5.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr Alkali elution amount: 0.40 μg / cm ² or less in 950 mm × 600 mm Film formation rate: 50 Å / sec [Comparison Example 4] Conditions Plasma excitation mechanism: a side S type, b side S type Tablet: SiO ₂ tablet Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 5.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr Alkali elution amount: 950 mm × 600 mm Within 0.45 μg / cm ² or less Film formation rate: 40 Å / sec As described above, according to Examples 3 and 4 of the present invention,
High quality SiO with high alkali barrier effect on large area substrate
_Two films can be formed at high speed.

The alkali elution amount investigation, which is a method for examining the alkali barrier effect, was carried out as follows.

A soda lime glass substrate (sample) with a SiO ₂ film having a thickness of 100 nm or less is cut, and a silicone resin is applied to the cut glass edge portion (the portion without SiO ₂ ). Then, the sample is placed at 100 ° C. for 2 hours.
Bake for hours. Thereafter, the container is placed in a container filled with pure water, the container is sealed, and heat treatment is performed in a thermostat (95 ° C. for 2 hours).
4 hours). After the heat treatment, the amount of Na eluted in pure water is quantified by flame photometry.

Table 2 below shows Examples 3 and 4, Comparative Example 3,
4 shows the measurement results.

[0036]

[Table 2]

Next, examples and comparative examples of MgO will be described.

Example 5 Conditions Plasma excitation mechanism: a-side S type, b-side N type Tablet: MgO tablet Substrate temperature: 200 ° C. Discharge current: 150 A each Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 4.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr I (111) / sum of all peak intensities (%): 950 mm × 6
50% or more within 00 mm Deposition rate: 50 Å / sec [Example 6] Conditions Plasma excitation mechanism: a side N type b side S type Tablet: MgO tablet Substrate temperature: 200 ° C. Discharge current: 150 A each: Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 4.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr I (111) / sum of all peak intensities (%): 950 mm × 6
50% or more within 00 mm Deposition rate: 50 Å / sec [Comparative Example 5] Conditions Plasma excitation mechanism: a side N type b side N type Tablet: MgO tablet Substrate temperature: 200 ° C. Discharge current: 150 A each: Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 4.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr I (111) / sum of all peak intensities (%): 950 mm × 6
40% or more within 00 mm Deposition rate: 50 Å / sec [Comparative Example 6] Conditions Plasma excitation mechanism: a side sS, b side S type tablet: MgO tablet Substrate temperature: 200 ° C. Discharge current: 150 A each: Substrate: 1000 mm × 650 mm soda lime glass substrate Pressure during film formation: 5.0 × 10 ⁻⁴ Torr Oxygen partial pressure: 1.0 × 10 ⁻⁴ Torr I (111) / sum of all peak strengths (%): 950 mm × 6
30% or more within 00 mm Deposition rate: 50 Å / sec As described above, according to Examples 5 and 6 of the present invention,
A high-quality MgO film having excellent crystallinity can be formed on a large-area substrate at a high speed, and a high-quality plasma display panel can be manufactured.

The following Table 3 shows Examples 5 and 6, Comparative Example 5,
6 shows the measurement results.

[0040]

[Table 3]

[0041]

As described above, according to the present invention, a vacuum vessel is provided with a plurality of plasma beam generators, magnetic field means for generating adjacent plasma beams, a focusing coil, and a ring on the hearth side. By reversing the direction of the magnetic poles of the permanent magnet and the electromagnetic coil, magnetic field interference is eliminated, and the large-area substrate has a small in-plane variation in specific resistance of ITO.
It became possible to form a film. Such an ITO film is extremely effective when applied to a color liquid crystal display or the like.

According to the present invention, high-quality SiO ₂ having a high alkali barrier effect can be formed on a large-area substrate at a high speed.

According to the present invention, high-quality MgO having excellent crystallinity can be formed on a large-area substrate at a high speed.
A high-quality plasma display panel can be provided.

[Brief description of the drawings]

FIG. 1 shows an ion plating apparatus used in the present invention.
FIG. 4 is a cross-sectional view showing a case where two plasma generating units are provided.

FIG. 2 is a longitudinal sectional view of one of the film forming apparatuses of the ion plating apparatus shown in FIG.

FIG. 3 is a longitudinal sectional view showing a conventional ion plating apparatus.

FIG. 4 is a view for explaining the directions of magnetic poles of the permanent magnet, the focusing coil, the annular permanent magnet, and the electromagnetic coil shown in FIG.

[Explanation of symbols]

 11 Vacuum container 14a, 14b Cathode 15b Glass tube 18 Carrier gas 19b First intermediate electrode 20b Second intermediate electrode 21a, 21b Annular permanent magnet 22a, 22b Electromagnetic coil 24a, 24b Converging coil 28b Main power supply 30a, 30b Hearth 31a, 31b Auxiliary electrode 35b Annular permanent magnet 36b Electromagnetic coil 41 Substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Tanaka 5-2 Sokai-cho, Niihama-shi, Ehime Prefecture Sumitomo Heavy Industries, Ltd. Niihama Works

Claims (5)

[Claims] 1. A vacuum vessel is provided with a plurality of plasma guns having magnet means, focusing coils provided in each plasma gun, and a hearth serving as an anode containing an evaporating substance corresponding to each plasma gun. An ion plating apparatus, wherein an annular permanent magnet and an electromagnet are provided around the hearth, and the magnet means of the plurality of plasma guns, the focusing coil, and the orientation of each magnetic pole of the annular permanent magnet and the electromagnet, A method for coating a metal oxide, wherein the substrate is uniformly coated with the metal oxide by inverting each corresponding element of adjacent plasma guns. 2. The method according to claim 1, wherein the metal oxide is indium oxide to which tin oxide is added, silicon oxide, or magnesium oxide. 3. The ITO transparent conductive film made of indium oxide to which tin oxide is added, wherein the film coated on the substrate has an in-plane variation in specific resistance within ± 7%. Metal oxide coating method. 4. The method according to claim 1, wherein a silicon oxide film having an alkali elution amount of 0.3 μg / cm ² or less is obtained on the substrate. 5. A magnesium oxide film having a peak intensity of a diffraction peak from the (111) plane of the X-ray diffraction spectrum of the magnesium oxide film coated on the substrate which is 50% or more of the sum of other peak intensities. 2. The method for coating a metal oxide according to claim 1, wherein