JP2006299311A - Metal oxide film, forming method therefor, apparatus for forming metal oxide film, gas discharge display device, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal oxide film with a higher secondary emission coefficient; a gas discharge display device realizing low power consumption and high precision by using the metal oxide film; a method for manufacturing them with high productivity; and a manufacturing apparatus for ideally realizing the method for manufacturing them. <P>SOLUTION: The metal oxide film includes MgO as a main component, which contains Ne atoms over the whole film. The forming method with the high productivity includes using a sputtering technique and a discharge gas containing Ar gas and Ne gas. The plasma display panel employs thus formed metal oxide film as a protective film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal oxide film, a method for forming the metal oxide film, a metal oxide film forming apparatus, a gas discharge display device using the metal oxide film as a protective film, and a method for manufacturing the same.

  One of the thin display devices is a plasma display panel (hereinafter referred to as “PDP”), and the surface discharge type PDP is in the spotlight especially from the viewpoint of size increase and life characteristics. As shown in FIG. 5, the surface discharge type PDP has a structure in which a discharge space is sandwiched between a front plate 31 and a back plate 32, and the front plate 31 has a scanning electrode on a glass substrate 311. A display electrode pair 34 including a sustain electrode, a dielectric layer 35, and a protective film 36 are sequentially formed. A back plate 32 has a band-like data electrode 37 on a glass substrate 321, and a dielectric layer. 38 are sequentially laminated, and the phosphor layer 310 and the barrier ribs 39 are formed on the dielectric layer 38.

The protective film 36 prevents the high energy ions generated by the discharge from spattering the surface of the dielectric layer 35 and deteriorating the discharge characteristics, and efficiently discharges secondary electrons into the discharge space. To do. In order to satisfy this characteristic, a metal oxide film called a so-called MgO film has often been used for the protective film 36 conventionally.
It is known that the secondary electron emission coefficient of the MgO film should be increased in order to reduce the power consumption of such a PDP and reduce the driving voltage.

In order to increase the secondary electron emission coefficient of the MgO film, the film was formed by the electron beam evaporation method. However, the electron beam evaporation method is difficult to obtain a dense film in the first place, and has process reproducibility. Since it is bad, there exists a subject that it is inferior to productivity, and it is unsuitable especially for the enlargement of a panel.
In view of this, film formation by sputtering has been attempted as a film that is denser than that obtained by electron beam evaporation (for example, Patent Document 1).
JP 2002-194539 A

However, the sputtering method can provide a better film than the electron beam evaporation method in terms of insulation and secondary electron emission coefficient, but its characteristics (especially the secondary electron emission coefficient) meet the requirements. In addition, there is a big problem that the productivity is inferior because the film formation rate is very slow compared with the electron beam evaporation method.
The present invention has been made in view of such problems, and as a first object, a metal oxide film mainly composed of MgO having a larger secondary electron emission coefficient and a composition for improving the productivity of the metal oxide film. An object is to provide a film method and a film forming apparatus. Also, as a second object, a gas discharge display device that achieves reduction in power consumption and high definition by using this metal oxide film as a protective film, and a manufacturing method for improving the productivity of the gas discharge display device are provided. The purpose is to do.

In order to achieve the above object, in the present invention, Ne atoms are dispersed inward in a metal oxide film which is used in a state facing the discharge space and mainly contains MgO.
In the present invention, Ne atoms are dispersed inside the metal oxide film, which is used as a protective film in the gas discharge display device and mainly contains MgO.
Here, the dispersion of Ne atoms inside the film means that Ne atoms are dispersed throughout the metal oxide film, and means that Ne atoms are present between MgO crystals or in the crystals. .

  Further, in the present invention, as a discharge gas, Ar is used as a discharge gas in contrast to a method for forming a metal oxide film formed on a substrate by sputtering using a discharge gas and sputtering a metal oxide or a sputtering target mainly containing metal. A mixed gas of a gas and a rare gas other than Ar gas, and among the atoms other than Ar atoms in the rare gas group, the metal oxide or the mass number of the metal atoms constituting the metal, A rare gas composed of atoms having the closest mass number was used.

Moreover, the manufacturing method of the gas discharge display apparatus of this invention formed the protective film which faces discharge space by the method in any one of Claim 5-9.
In addition, the metal oxide film forming apparatus of the present invention includes a reaction vessel capable of accommodating a sputtering target and a substrate therein, a first gas introduction path for introducing a discharge gas into the reaction vessel, and the reaction vessel A metal oxide film forming apparatus provided with a second gas introduction path for introducing an oxidizing gas in the reaction vessel is provided with a gas decomposing means for decomposing at least a part of the discharge gas. The second gas introduction path was connected to the reaction vessel at a position closer to the substrate than the first gas introduction path.

  As described above, in the metal oxide film of the present invention, an energy level similar to an oxygen defect can be formed between the energy band gaps by MgO as a main component and Ne atoms dispersed inside the film. , Electrons are more likely to be emitted than conventional metal oxide films that do not contain Ne atoms. If this is used for a protective film of a gas discharge display device (especially a PDP), it is possible to reduce the discharge start voltage and improve the discharge delay, and to realize a reduction in power consumption and high definition of the PDP. it can.

When the Ne atom content in the film is set to 2 × 10 ¹⁷ [pieces / cm ³ ] or more and 1 × 10 ¹⁹ [pieces / cm ³ ] or less, the discharge start voltage is ensured as compared with the prior art not including Ne atoms. It is preferable because the crystallinity and sputtering resistance of the film can be maintained while reducing the film thickness.
Furthermore, if the metal oxide film of the present invention is applied to another device such as a plasma processing apparatus that faces the discharge space, it is possible to reduce the discharge starting power and increase the plasma density.

  Moreover, according to the method for producing a metal oxide film of the present invention, the metal oxide or the metal is constituted of atoms other than Ar atoms in the rare gas group as the rare gas other than Ar gas. Since the noble gas composed of atoms having the mass number of the metal atom and the closest mass number is included, among the noble gas atoms included in the noble gas group, the size of the noble gas atom and the metal atom is Therefore, the use of the rare gas atom makes it easier to sputter the metal target compared to sputtering with only Ar atoms, and can improve the deposition rate. Since atoms easily substitute for metal atoms or oxygen atoms in the formed metal oxide film, energy levels similar to oxygen defects are formed between the energy band gaps. It is to be able to can form a release easily the metal oxide film more electrons.

When sputtering is performed after the oxidizing gas is decomposed into atoms, it is preferable to perform sputtering by introducing the oxidizing gas in the vicinity of the substrate, because process reproducibility can be further improved.
Therefore, when these film forming methods are employed in a method for manufacturing a gas discharge display device (particularly a PDP) as a process for forming a protective film for protecting an electrode or a dielectric layer, a low-power consumption and high-definition gas discharge A display device (particularly a PDP) can be manufactured with high productivity.

In addition, an improvement in productivity (particularly process reproducibility and film formation speed) has an effect of reducing manufacturing costs.
Furthermore, according to the production apparatus of the present invention, the metal oxide film can be preferably produced, and the production method can be preferably implemented.

(Embodiment 1)
<Metal oxide film and PDP in this embodiment>
In the present embodiment, the metal oxide film is mainly composed of MgO, and Ne atoms are dispersed inside the film.
That is, in the metal oxide film in the present embodiment, Ne atoms are dispersed throughout the film so as to exist between or within MgO crystals.

For example, the metal oxide film is formed on a glass plate by a sputtering method. In the sputtering method, a metal target mainly composed of MgO molecules is used, and Ne gas is included in the discharge gas. It is formed by.
The metal target is not limited to this, and may be a metal target mainly composed of Mg. In that case, not only Ne gas but also oxidizing gas typified by O ₂ gas is mixed in the discharge gas.

In the present embodiment, the PDP employing the metal oxide film as a protective film is made of a transparent electrode made of ITO, a bus electrode containing Ag as a main component, and a low melting point glass on one main surface of the glass substrate. The dielectric layers are sequentially laminated, and a front plate formed by laminating the metal oxide film on the main surface of the dielectric layer and stripe-shaped barrier ribs are formed on the main surface, and phosphors are interposed between the barrier ribs. The coated and baked back plate is opposed to each other across the space, and is sealed with a sealant at the edge of the front plate and the back plate, and Xe / Ne gas is sealed in the space.
<Metal Oxide Film Forming Apparatus in this Embodiment>
An apparatus for forming a metal oxide film in this embodiment will be described with reference to FIG.

FIG. 2 is a schematic configuration diagram showing the configuration of the metal oxide film forming apparatus in the present embodiment.
As shown in FIG. 2, the forming apparatus includes a reaction vessel 12, and includes two gas introduction paths 18 and 19 for introducing discharge gas and oxidizing gas into the reaction vessel 12, and the inside of the reaction vessel 12. A vacuum pump 11 for reducing the pressure and a high-frequency power source 17 for applying a voltage to the discharge electrode 14 and the substrate stage 16 installed in the reaction vessel 12 are connected to the reaction vessel 12.

The discharge electrode 14 has a function of placing the metal target 13, and the substrate stage 16 supports the substrate 15 on which the metal oxide film in the present embodiment is to be formed and functions as a counter electrode of the discharge electrode 14. To do.
The second gas introduction path 19 is connected to a position closer to the substrate 15 than the first gas introduction path 18 and includes a gas decomposition apparatus 110 for decomposing molecular gas into atoms. A cover 111 is provided around the substrate stage 16 in order to adjust the flow of gas introduced from the second gas introduction path 19.
<Metal Oxide Film Forming Method and PDP Manufacturing Method in the Present Embodiment>
A method for forming a metal oxide film in this embodiment will be described with reference to FIGS. In the forming method, the above-described metal oxide film forming apparatus is used.

FIG. 3 is a schematic process diagram showing a process of forming a metal oxide film containing MgO as a main component.
First, a metal target 13 mainly composed of MgO is placed on the discharge electrode 14 installed in the reaction vessel 12, and a glass substrate is placed on the substrate stage 16 as a substrate 15 on which a metal oxide film is to be formed. Then, the reaction vessel 12 is sealed, and then the inside of the reaction vessel 12 is depressurized by the vacuum pump 11 (not shown).

As a result, the metal target 13 mainly composed of MgO and the substrate 15 are arranged to face each other with a predetermined decompression space interposed therebetween. From the first gas introduction path 18 as shown in FIG. The discharge gas 20 is introduced, and O ₂ gas is introduced into the vicinity of the substrate 15 as the oxidizing gas 21 from the second gas introduction path 19.
As the discharge gas 20, a mixed gas in which Ne gas is added to Ar gas at a ratio of 10% is used.

  In the present embodiment, the Ar / Ne gas Ne ratio is set to 10% as the conditions for forming the MgO film, but the present invention is not limited to this ratio. However, when the rare gas is only Ne gas, it is considered that the electron density in the plasma is greatly reduced, and the film formation rate by sputtering is lower than the conventional one. For this reason, Ar gas is necessary for maintaining the electron density of the plasma, and in order to increase the deposition rate while incorporating Ne atoms in the MgO film, the Ne ratio in the Ar / Ne gas is 2%. To 50% is preferable.

In this embodiment, O ₂ gas is added in addition to Ar and Ne gas gases. However, since MgO is used as the metal target material, it is not always necessary to add O ₂ gas. However, in order to further improve the properties such as the insulation properties of the MgO film, it is preferable to add an oxidizing gas in addition to the Ar and Ne gases. Examples of the oxidizing gas include O ₃ , CO, CO ₂ , NO, and NO ₂ in addition to O ₂ used in the present embodiment. It is preferable to use O ₃ because it is more reactive than O _2. It is preferable to use CO, CO ₂ , NO, or NO ₂ gas to control film characteristics by adding elements such as C and N to the MgO film. Is preferable.

In the present embodiment, the gas decomposition apparatus 110 provided in the second gas introduction path 19 is not operated, and the O ₂ gas is introduced as it is into the reaction vessel 12 as the oxidizing gas 21.
Then, as shown in FIG. 3B, for example, high-frequency power of 13.56 [MHz] is applied from the high-frequency power source 17 to the discharge electrode 14 to turn the discharge gas 20 and the oxidizing gas 21 into plasma and perform sputtering. As a result, a metal oxide film mainly composed of MgO is formed on the substrate 15.

In the present embodiment, the case of forming the MgO film is shown, but the present invention is not limited to this. For example, when forming the SrO film, Kr gas is included in the discharge gas and SrO is used as the metal target. It can implement similarly by using. Since the rare gas atom having the mass number closest to the mass number of the metal atom (Sr) constituting the metal target is a Kr atom, the sputtering rate of Kr ions is increased when using a metal target mainly composed of SrO. It becomes higher than that of Ar ions. Therefore, adding not only Ar gas but also Kr gas as the discharge gas contributes to an increase in the deposition rate. In the case of forming the _La 2 _{O 3} film, a discharge gas contained Xe gas can be carried out in the same manner by using _La 2 _{O 3} as a metal target. In addition, the CeO film can be formed by including Xe gas in the discharge gas and using CeO as the metal target. Since the rare gas atom having the mass number closest to the mass number of the metal atoms (La, Ce) constituting the metal target is an Xe atom, a metal target mainly composed of La ₂ O ₃ , CeO is used. The sputtering rate of Xe ions is higher than that of Ar ions. Therefore, adding not only Ar gas but also Xe gas as a discharge gas contributes to an increase in film formation rate, and improvement of characteristics such as secondary electron emission coefficient can be expected for these films.

In these cases, it is not always necessary to add the oxidizing gas. However, it is preferable to add an oxidizing gas in order to further improve the characteristics such as the insulating properties of the film.
The manufacturing method of the PDP in the present embodiment is the same as the conventional manufacturing method except that the above-described metal oxide film forming method is employed in the protective film forming step. In brief, a transparent electrode made of an ITO film and a bus electrode made of a film containing Ag as a main component are sequentially formed on a glass substrate, and then a low-melting glass is printed and baked by a screen printing method. And a MgO film having a thickness of, for example, 600 [nm] is deposited on the dielectric layer by the above-described forming method to form a front plate. The back plate is the same as the conventional one in which striped partition walls are formed. The front plate and the back plate are sealed and exhausted, and Xe / Ne gas (Xe partial pressure 10%) is sealed in the discharge space after exhausting, for example, at 500 [Torr] (66661 [Pa]) to manufacture a PDP. .
<< Effects of Metal Oxide Film and PDP in this Embodiment >>
In the present embodiment, Ne atoms are dispersed inward of the metal oxide film containing MgO as a main component, so that energy levels similar to oxygen defects are formed between the MgO band gaps. Therefore, when the metal oxide film is arranged facing the discharge space and a voltage is applied, the secondary electron emission coefficient is increased as compared with a metal oxide film mainly composed of MgO not containing Ne atoms. Can be made.

In this embodiment, since Ne atoms are dispersed inside the protective film in the PDP adopting a metal oxide film mainly composed of MgO as a protective film, the protective film does not contain Ne atoms. As compared with the above, the secondary electron emission coefficient of the protective film can be increased, the driving voltage of the PDP can be reduced, and the power consumption of the PDP can be reduced.
When the secondary electron emission coefficient of the protective film is improved, the discharge delay time during the sustain discharge is reduced and the discharge variation for each discharge cell is suppressed. Therefore, the PDP in the present embodiment performs higher definition display. be able to. In addition, since the discharge delay time during the write discharge is also reduced, the address time per line can be shortened. The time required to address the entire screen can be expressed by the product of the address time per line and the number of scan lines. Therefore, if the address time per line is shortened, more scan lines can be addressed. it can. In other words, the PDP in this embodiment can perform display with higher definition.

Furthermore, because of the above effects, a driving IC having a low withstand voltage can be combined with this PDP, and therefore, a PDP with a low manufacturing cost can be realized in this embodiment.
<< Effect of Metal Oxide Film Forming Apparatus in This Embodiment >>
In the metal oxide film forming apparatus according to the present embodiment, two gas introduction paths 18 and 19 are provided in the sputtering apparatus, and one of these gas introduction paths is used as a second gas introduction path 19 in the vicinity of the substrate stage 16. Since the oxidizing gas 21 is provided so as to be introduced, when a metal oxide film is formed on the surface of the substrate 15, the oxidation reaction near the substrate 15 can be promoted, and the oxidation reaction on the surface of the metal target 13. Can be suppressed. As a result, in the forming apparatus, a metal oxide film can be formed on the surface of the substrate 15 at a higher speed than in a sputtering apparatus having a single gas introduction path.
<< Effects of Metal Oxide Film Forming Method and PDP Manufacturing Method in Present Embodiment >>
In the method for forming a metal oxide film according to the present embodiment, in the sputtering method, the metal target 13 containing MgO as a main component is used, and the discharge gas 20 contains Ne gas in addition to Ar gas. Since Ne atoms can be introduced into the film in the formation process, a metal oxide film mainly composed of MgO in which Ne atoms are dispersed in the film can be formed.

Further, in this forming method, by introducing the oxidizing gas 21 from the vicinity of the substrate 15, the oxidation reaction in the vicinity of the substrate 15 can be promoted, and the oxidation reaction in the vicinity of the metal target 13 can be suppressed. Compared with the invention described in Document 1, the film formation rate can be improved.
In the manufacturing method of the PDP in the present embodiment, the metal oxide film forming method described above is used in the protective film forming step, so that the metal oxide film mainly composed of MgO in which Ne atoms are dispersed inside is protected. The film can be formed as a film, and the manufacturing speed can be improved as compared with the method for manufacturing a PDP in which the invention described in Patent Document 1 is employed in the protective film forming step.

{Evaluation test}
[Evaluation Test 1]
In order to verify the effect of the metal oxide film in the present embodiment, as a sample, a PDP employing the metal oxide film in the present embodiment as a protective film is prepared, and as a comparison target, formed by an electron beam evaporation method, A PDP in which a metal oxide film mainly composed of MgO is adopted as a protective film, and a PDP formed by a conventional sputtering method and a metal oxide film mainly composed of MgO not containing Ne atoms are adopted as a protective film. We prepared and measured the discharge start voltage, discharge delay time and Ne atom concentration during sustain discharge for these samples, and tried to evaluate the performance.

Fig. 1 shows the measurement results of the discharge start voltage during the sustain discharge. FIG. 1 is a characteristic diagram showing the discharge start voltage during the sustain discharge of each sample. As is clear from FIG. 1, it was confirmed that the discharge starting voltage was lowest in the PDP in which the metal oxide film in the present embodiment was applied to the protective film.
Further, as a result of measuring the discharge delay time for each of the above samples, it was confirmed that the discharge delay time was the shortest in the PDP in which the metal oxide film according to the present embodiment was applied to the protective film, similarly to the discharge start voltage.

Furthermore, as a result of measuring the Ne atom concentration for each of the above samples by secondary ion mass spectrometry (SIMS), 2.4 × 10 ¹⁷ [pieces / cm ³ ] Ne atoms in the metal oxide film in this embodiment. In the sample in which Ne gas was not mixed, Ne atoms could not be detected in the film.
[Evaluation Test 2]
In order to verify the effect of the method for forming a metal oxide film in this embodiment, film formation is performed by controlling the discharge time in the voltage application step and measuring the film thickness of the deposited metal oxide film. The speed was calculated. For comparison, film deposition was performed by introducing only Ar gas and O ₂ gas without mixing Ne gas, and the film formation rates were similarly calculated, and these film formation rates were compared and evaluated.

As a result, in this evaluation test, it was confirmed that the formation method of the metal oxide film in the present embodiment was increased by about 5% with respect to the formation method of the comparison target.
<Consideration for Evaluation Test 1>
In the measurement results of the discharge start voltage and the discharge delay time during the sustain discharge, the metal oxide film in the present embodiment obtained the best results from the measurement result of the Ne atom concentration based on MgO as the main component. This is probably because the secondary electron emission coefficient was improved by dispersing Ne atoms in the metal oxide film, and the effectiveness of the metal oxide film in this embodiment was proved.

  The following can be considered as factors for improving the secondary electron emission coefficient. That is, the atomic mass number and the atomic size are in a proportional relationship, and Ne atoms, Mg atoms, and O atoms are very close in mass, so Ne atoms are the main component in the metal oxide film. The size of the atoms is close to that of both Mg atoms and O atoms. Therefore, it is considered that Ne gas is easily taken into the metal oxide film as compared with other rare gas atoms, and Ne atoms taken into the film are replaced with Mg atoms or O atoms in the MgO crystal structure. Thus, it is presumed that an energy level similar to oxygen defects is formed between the MgO band gaps.

As the energy level is formed, electrons are emitted at a relatively low energy. Therefore, the density of the region where the energy level is formed in the metal oxide film is increased, so that the secondary electron emission coefficient is further increased. It seems that it has grown.
From the measurement result of the Ne atom concentration, it is preferable that the Ne atom content is 2.0 × 10 ¹⁷ [pieces / cm ³ ] or more in order to ensure the above effect. However, since the crystallinity of the metal oxide film and the sputter resistance are lowered even if it is increased infinitely, the Ne atom content is desirably 1.0 × 10 ¹⁹ [pieces / cm ³ ] or less.
<Consideration for Evaluation Test 2>
As a result of the film formation rate test, it can be confirmed that the formation method of the metal oxide film in the present embodiment is higher than the formation method of the comparison object, and the metal oxidation in the present embodiment The effectiveness of the film formation method was proved.

  The reason is that the mass number of Ne atoms constituting the Ne gas included in the discharge gas 20 is closest to the mass number of metal atoms (Mg) constituting the metal target 13 among the rare gas atoms. When a metal target containing MgO as a main component is used, the sputtering rate of Ne ions is higher than that of Ar ions. Therefore, it is necessary to add not only Ar gas but also Ne gas as the discharge gas 20. This is thought to have contributed to the increase in Further, by introducing the oxidizing gas 21 from the vicinity of the substrate 15 during film formation, the oxidation reaction in the vicinity of the substrate 15 can be promoted and the oxidation of the surface of the metal target 13 can be suppressed. Is thought to have increased.

As described above, the characteristics such as the secondary electron emission coefficient required for the film are improved as the film forming speed is increased during film formation. This is because the gas discharge display device (for example, an MgO film currently used as a protective film) This is desirable not only in that the productivity and characteristics of PDP) are greatly improved, but also in that the scope of application may be expanded to new fields.
(Embodiment 2)
<Metal Oxide Film Forming Method and PDP Manufacturing Method in the Present Embodiment>
A method for forming a metal oxide film in this embodiment will be described with reference to FIGS. Also in this forming method, the metal oxide film forming apparatus shown in Embodiment Mode 1 is used.

FIG. 4 is a schematic process diagram showing a process of forming a metal oxide film containing MgO as a main component.
In the present embodiment, the difference from the first embodiment is that the gas decomposition apparatus 110 that was not operated in the first embodiment is operated, and a metal target mainly composed of Mg is used as the metal target 13. Since the Kr gas not included in the first embodiment is introduced from the second gas introduction path 19 together with the O ₂ gas, the description of the same procedure as that described in the first embodiment is omitted.

Since the placement process and the decompression process are the same as those in the first embodiment, description thereof is omitted. Thereafter, a mixed gas 20 of Ar gas and Ne gas (Ne ratio 10%) is introduced from the first gas introduction path 18, and a mixed gas of O ₂ gas and Kr gas (O ₂ ratio 5%) from the second gas introduction path 19. ) Is introduced (not shown).
In the present embodiment, the deposition ratio of the MgO film is 10% for the Ne ratio of Ar / Ne gas. However, the present invention is not limited to this ratio. However, in order to disperse Ne atoms in the MgO film and to improve the film formation rate, it is preferable to set the Ne ratio in Ar / Ne gas to 2% to 50%.

Although O ₂ gas is added as the oxidizing gas, the present invention is not limited to this, and examples thereof include O ₃ gas, CO gas, CO ₂ gas, NO gas, and NO ₂ gas in addition to O ₂ gas. It is preferable to use O ₃ gas because it is more reactive than O ₂ gas, and using CO gas, CO ₂ gas, NO gas, or NO ₂ gas is to add elements such as C and N to the MgO film. Is preferable because the film characteristics can be controlled.

Then, through the Kr / O ₂ gas of the gas decomposition apparatus provided on the second gas introduction path 19 110 (although abbreviated in FIG. 4, a microwave plasma apparatus particularly), a part of the O ₂ gas After being decomposed into atoms, an oxidizing gas 22 decomposed into atoms is introduced into the reaction vessel 12 as shown in FIG.
Although the microwave plasma apparatus is used as the gas decomposition apparatus 110 for the decomposition of the oxidizing gas 22 (Kr / O ₂ gas in the present embodiment) introduced from the second gas introduction path 19, it is not limited to this. Instead, other plasma decomposition apparatuses such as inductively coupled plasma, photodecomposition apparatuses, thermal decomposition apparatuses, and the like may be used.

In the present embodiment, the Kr gas introduced from the second gas introduction path 19 plays a role of efficiently decomposing the O ₂ gas in the gas decomposition apparatus 110. This is because the O ₂ gas is efficiently decomposed into atoms by the excited Kr generated in the gas decomposition apparatus 110, and the decomposition efficiency of the O ₂ gas is improved. This is because the energy of excitation Kr is close to the binding energy of O ₂ , and the same effect can be obtained by Xe.

O ₂ gas is decomposed in advance if a large amount of O ₂ gas is directly introduced into the reaction vessel 12, plasma energy is consumed for dissociation of O ₂ , and the density of plasma necessary for sputtering decreases. Because it will end up. Therefore, if this is decomposed atomically by the gas decomposing apparatus 110 in advance, it is possible to prevent the plasma density in the reaction vessel 12 from decreasing and to increase the reactivity between the sputtered Mg atoms and O atoms. Therefore, it is very preferable when the metal target 13 mainly composed of Mg is used and the metal oxide film mainly composed of MgO is formed on the substrate 15 as in the present embodiment.

After introducing the gas as described above, the substrate 15 is sputtered by generating plasma discharge by applying high frequency power of 13.56 MHz, for example, to the discharge electrode 14 as shown in FIG. 4B. A metal oxide film is formed thereon.
Since the manufacturing method of the PDP in the present embodiment is the same as that already shown in the first embodiment, the description thereof is omitted.
<< Effects of Metal Oxide Film Forming Method and PDP Manufacturing Method in Present Embodiment >>
In the method for forming a metal oxide film in the present embodiment, as in the method for forming a metal oxide film in the first embodiment, a metal oxide film mainly composed of MgO in which Ne atoms are dispersed inward is formed. In addition, the film formation rate can be improved as compared with the invention described in Patent Document 1.

Furthermore, in the formation method, the O ₂ gas is decomposed into atoms by the gas decomposition apparatus 110 before introducing the oxidizing gas into the reaction vessel 12, so that the plasma density required in the sputtering method is not reduced, In addition, the reactivity between O atoms and Mg atoms can be improved, and the film formation rate can be further improved, which is preferable.
In the PDP formation method in the present embodiment, since the above-described metal oxide film formation method is used in the protective film formation step, Ne atoms are dispersed inside the film in the same manner as in the PDP manufacturing method in the first embodiment. The metal oxide film containing MgO as a main component can be formed as a protective film, and the manufacturing speed can be improved as compared with the PDP manufacturing method employing the invention described in Patent Document 1 in the protective film forming step. Furthermore, in the protective film formation step, the O ₂ gas is decomposed into atoms by the gas decomposition apparatus 110 before introducing the oxidizing gas into the reaction vessel 12, so that the film formation rate can be further improved. .

In this embodiment, Kr gas is introduced to promote decomposition of O ₂ gas, and naturally enters the reaction vessel 12 and may be ionized. However, the gas decomposition apparatus 110 has already been in an excited state. Therefore, the risk of depriving the plasma energy in the reaction vessel 12 and lowering its density is considered to be small, and the sputtering rate by Kr ions is smaller than that of Ar ions and Ne ions, so there is an adverse effect. Is considered small. The same applies to Xe gas.

{Evaluation test}
[Evaluation Test 1]
In order to verify the effect of the metal oxide film formation method in this embodiment, the discharge time in the voltage application step in the formation method is controlled, and the thickness of the deposited metal oxide film containing MgO as a main component is measured. By doing so, the film formation rate was calculated. For comparison, film deposition was performed without mixing Ne gas, the film formation speed was calculated in the same manner, and these film formation speeds were comparatively evaluated.

As a result, it was confirmed that the metal oxide film formation method in this embodiment increased the film formation rate by about 20% as compared with the comparative formation method.
<Consideration for Evaluation Test 1>
The reason why the film forming speed of the metal oxide film forming method in this embodiment is improved is as follows. That is, when a large amount of O ₂ gas is directly introduced into the reaction vessel, plasma energy is consumed for dissociation of the O ₂ gas, and the plasma density required for sputtering decreases. It is considered that the decomposition of the plasma density in the reaction vessel can be prevented by decomposing into atoms and the reactivity between the sputtered Mg atoms and O atoms can be increased. By introducing O ₂ gas decomposed in advance atomic from the vicinity of the substrate, together with oxidation of the substrate near is further promoted, it is possible to suppress the oxidation of the metal target surface composed mainly of Mg It is thought that it was made.
(Embodiment 3)
<Method for Forming Metal Oxide Film in This Embodiment>
A method for forming a metal oxide film in this embodiment will be described. Also in this forming method, the metal oxide film forming apparatus shown in Embodiment Mode 1 is used.

The formation method in the present embodiment is the same as the manufacturing method in the second embodiment, in that a metal target mainly composed of MgO is used as the metal target 13, and CO ₂ gas is used as the oxidizing gas. Therefore, a description of the same procedure as that described in the second embodiment will be omitted and will be described with reference to FIG. In the present embodiment, the Kr gas used in the second embodiment is not used.

In the present embodiment, since the main component of the metal target 13 is MgO, the rare gas atom having the mass number closest to the mass number of the metal atom (Mg) constituting the metal target 13 is a Ne atom.
As shown in FIG. 4 (a), a mixed gas 20 of Ar gas and Ne gas (Ne ratio 10%) is introduced from the first gas introduction path 18, and the CO ₂ gas is gas decomposed from the second gas introduction path 19. A part thereof is decomposed into atoms by 110 (specifically, a microwave plasma apparatus) and then introduced.

In the present embodiment, the microwave plasma apparatus is used as the gas decomposition apparatus for decomposing the oxidizing gas (CO ₂ gas in the present embodiment) introduced from the second gas introduction path. However, the present invention is not limited to this. However, other plasma decomposition apparatuses such as inductively coupled plasma, photodecomposition apparatuses, thermal decomposition apparatuses, and the like may be used.
As shown in FIG. 4B, a high frequency power of 13.56 [MHz], for example, is applied to the discharge electrode 14 to generate plasma discharge and perform sputtering, and a metal mainly composed of MgO on the substrate 15. An oxide film is formed.
<< Effect of Forming Method of Metal Oxide Film in This Embodiment >>
In the method for forming a metal oxide film in the present embodiment, a metal oxide film mainly composed of MgO in which Ne atoms are dispersed inside the film is formed as in the method for forming a metal oxide film in the second embodiment. In addition, the film formation rate can be improved as compared with the invention described in Patent Document 1, and the reactivity between O atoms and Mg atoms can be achieved without reducing the plasma density required in the sputtering method. Thus, the film formation rate can be further improved.

Further, in this formation method, while adding desired impurities (C atoms in the present embodiment) together with Ne atoms to the inside of the metal oxide film containing MgO as a main component, the invention described in Patent Document 1 is added. In comparison, the film formation rate can be improved.
{Evaluation test}
[Evaluation Test 1]
In order to verify the effect of the method for forming a metal oxide film in this embodiment, the presence or absence of Ne atoms and C atoms in a metal oxide film containing MgO as a main component was investigated.

As a result, it was confirmed that Ne atoms and C atoms were contained inside the metal oxide film.
[Evaluation Test 2]
In order to verify the effect of the method for forming a metal oxide film in the present embodiment, an evaluation test similar to the evaluation test performed in the second embodiment was performed.

As a result, in this evaluation test, it was confirmed that the film formation rate in the present embodiment was increased by about 5% as compared with the comparative formation method.
<Consideration for evaluation test>
From the results of the above test, in the formation method in the present embodiment, while adding desired impurities (C atoms in the present embodiment) together with Ne atoms to the inside of the metal oxide film mainly composed of MgO, It was proved that the film formation rate can be improved as compared with the invention described in Patent Document 1.
(Other)
In the first embodiment, the second embodiment 2, and the third embodiment, an example in which the MgO film of the present invention is applied to an AC type surface discharge PDP is shown. The present invention can be applied to other gas discharge display devices, and effects such as reduction of discharge voltage are expected.

  Moreover, it is also possible to apply the MgO film of the present invention to other devices used in a state of facing a discharge space such as a plasma processing apparatus. Specifically, by forming the MgO film of the present invention inside the microwave introduction window in the microwave plasma processing apparatus, the effect of reducing the discharge starting power and increasing the plasma density can be obtained.

  According to the metal oxide film of the present invention, the secondary electron emission coefficient is further increased. In particular, when the metal oxide film of the present invention is used as a protective film of a gas discharge display device, the discharge voltage of the gas discharge display device can be reduced and the discharge delay during the sustain discharge can be improved. As a result, low power consumption and high definition of the plasma display panel, which is one of the gas discharge display devices, can be realized, so that the video equipment industry and the advertising equipment industry such as large televisions, high-definition televisions or large display devices It can be used for industrial equipment and other industrial fields, and its industrial applicability is very wide and large.

It is a characteristic view of the discharge start voltage of PDP which employ | adopted MgO film | membrane of this invention for the protective film. It is a block diagram of the manufacturing apparatus of the MgO film | membrane in embodiment of this invention. It is a schematic diagram which shows the film-forming process of the MgO film | membrane in the formation apparatus in 1st Embodiment. It is a schematic diagram which shows the film-forming process of the MgO film | membrane in the formation apparatus in 2nd Embodiment. It is a structural diagram of a conventional plasma display panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Vacuum pump 12 Reaction container 13 Metal target 14 Discharge electrode 15 Substrate 16 Substrate stage 17 High frequency power supply 18 First gas introduction path 19 Second gas introduction path 20 Discharge gas 21 Oxidizing gas 22 Oxidized oxidizing gas 110 Gas decomposition device 111 Cover 31 Front plate 32 Back plate 311, 321 Glass substrate 34 Display electrode pair 341, 342 Transparent electrode 343, 344 Bus electrode 35 Dielectric layer 36 Protective film 37 Data electrode 38 Dielectric layer 39 Partition

Claims (13)

  A metal oxide film which is used in a state of facing a discharge space, and which has MgO as a main component and Ne atoms are dispersed inside the film. 2. The metal oxide film according to claim 1, wherein the content of Ne atoms in the film is 2 × 10 ¹⁷ [pieces / cm ³ ] or more and 1 × 10 ¹⁹ [pieces / cm ³ ] or less. A gas discharge display device in which a first substrate and a second substrate are arranged to face each other with a discharge space interposed therebetween, and a protective film mainly composed of MgO is formed on the discharge space side main surface of the first substrate,
A gas discharge display device characterized in that Ne atoms are dispersed inside the protective film. The gas discharge display device according to claim 3, wherein the content of Ne atoms in the protective film is 2 × 10 ¹⁷ [pieces / cm ³ ] or more and 1 × 10 ¹⁹ [pieces / cm ³ ] or less. A method for forming a metal oxide film, wherein a film is formed on a substrate by sputtering a sputtering target mainly composed of a metal oxide or metal using a discharge gas,
The discharge gas includes Ar gas and a rare gas other than the Ar gas,
The rare gas other than the Ar gas is composed of atoms having the closest mass number to the metal oxide or the metal atom constituting the metal among the atoms other than the Ar atom in the rare gas group. A method for forming a metal oxide film, wherein a rare gas is used. The sputtering target contains MgO or metal Mg as a main component,
Ne gas is included in the discharge gas as the rare gas,
6. The method of forming a metal oxide film according to claim 5, wherein the metal oxide film is formed with MgO as a main component.   The method for forming a metal oxide film according to claim 5 or 6, wherein the discharge gas contains an oxidizing gas.   The method for forming a metal oxide film according to claim 7, wherein the oxidizing gas is decomposed into atoms before the oxidizing gas is included in the discharge gas.   A discharge gas is introduced into a reaction vessel containing a metal oxide or metal-based sputtering target and the substrate from a first gas introduction path connected to a position close to the sputtering target, and the first gas 9. The method for forming a metal oxide film according to claim 7, wherein the film is formed by introducing an oxidizing gas from a second gas introduction path connected to a position closer to the substrate than the introduction path.   A method for manufacturing a gas discharge display device, comprising forming a protective film facing the discharge space by the method according to claim 5. A reaction vessel capable of accommodating a sputtering target and a substrate therein, a first gas introduction passage for introducing a discharge gas and a second gas introduction passage for introducing an oxidizing gas into the reaction vessel. A metal oxide film forming apparatus provided with
Gas decomposing means for decomposing at least a part of the discharge gas is provided, and the second gas introduction path is closer to the substrate storage planned position in the reaction vessel than the first gas introduction path. A metal oxide film forming apparatus connected to the reaction vessel. The reaction vessel is capable of storing a sputtering target mainly composed of metal oxide or metal,
The first gas introduction path introduces a discharge gas containing Ar gas and a rare gas other than the Ar gas,
The rare gas other than the Ar gas is composed of atoms having a mass number closest to the metal oxide or the metal atom constituting the metal in the atoms other than the Ar atom in the rare gas group. The metal oxide film forming apparatus according to claim 11. The reaction vessel is capable of storing a sputtering target mainly composed of a metal oxide or metal containing Mg atoms as constituent elements,
13. The metal oxide film formation according to claim 12, wherein the first gas introduction path introduces a discharge gas containing Ar gas and Ne gas as a rare gas other than the Ar gas. apparatus.

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