KR20110009240A - Method for manufacturing plasma display panel and film forming apparatus - Google Patents

Abstract

Stabilize the film quality of the protective film. When evaporating a metal oxide while conveying a film-forming object, metal oxide is evaporated so that a static film-forming rate may be 40 nm / sec or more, introducing a large amount of water and oxygen into a vacuum chamber. The luminescence intensity at the time of evaporating a metal oxide is measured, and the measurement result is fed back to the output of the heating apparatus (electron gun 41). Since luminescence intensity is directly related to film quality, such as (111) intensity | strength, the protective film with favorable film quality, such as crystal orientation, film density, and optical characteristics, can be formed stably.

Description

Manufacturing method of plasma display panel, film-forming apparatus {METHOD FOR MANUFACTURING PLASMA DISPLAY PANEL AND FILM FORMING APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a technique for forming an MgO film suitable for a protective film of a panel used in a PDP display device.

Background Art Conventionally, plasma display panels (PDPs) are widely used in the field of display devices, and in recent years, large screens, high quality and low cost PDPs are required.

At present, PDPs have a mainstream three-electrode surface discharge type in which a front plate on which a sustain electrode and a scan electrode are formed on a glass substrate and a back plate on which an address electrode is formed on a glass substrate are bonded.

Discharge gas is enclosed between the front plate and the back plate. When a discharge is generated by applying a voltage between the scan electrode and the address electrode, the encapsulated discharge gas is converted into plasma to emit ultraviolet rays. When the phosphor is placed at the position where irradiated ultraviolet rays are irradiated, the phosphor is excited by the ultraviolet rays and the visible light is emitted.

Generally, metal oxide films, such as MgO and SrO, are formed on a sustain electrode and a scanning electrode for the purpose of forming a dielectric film, and protecting a dielectric and emitting secondary electrons thereon.

When an alternating voltage is applied to the scan electrode and the sustain electrode in order to maintain the discharge, cations generated by the plasma of the discharge gas are incident on the scan electrode side and the sustain electrode side. The sustain electrode and the scan electrode and the dielectric film on the electrodes are formed on the protective film. Is protected from cations.

In addition, attempts have been made to add Ca, Al, Si, Mn, Eu, Ti, water, hydrogen and the like to the MgO-based protective film in order to improve luminous efficiency, improve discharge delay, and improve γ (secondary electron yield). It is done (for example, nonpatent literature 1).

 (Non-Patent Document 1) Preliminary Collection of the 43rd PDP Technology Discussion Conference, July 5, 2006, p32 ~ p52

 (Patent Document 1) Japanese Unexamined Patent Publication No. 2007-107092

 (Patent Document 2) Japanese Unexamined Patent Publication No. 2007-119831

 (Patent Document 3) Japanese Unexamined Patent Publication No. 2006-149833

It is considered that the protective film containing MgO is more likely to emit secondary electrons as the peak intensity in the (111) orientation is high, and the higher the refractive index is, the more compact and sputter resistant, the following characteristics are generally required for the PDP protective film. .

 (1) The crystal orientation is (111) and the peak intensity in XRD (X Ray Diffraction, X-ray diffraction) is 1500 cps (counts per second) or more.

 (2) The filling factor (film density) is 82% or more (the refractive index is about 1.6 or more).

Although it is preferable to satisfy all of the above-mentioned characteristics (1) and (2), and to have high peak intensity and high filling rate, the film density tends to decrease in film formation conditions for improving crystal orientation, and the film density is high. There exists a tendency for crystal orientation to fall on film-forming conditions to make.

In short, the film forming conditions for improving the above characteristics are opposite. Therefore, when producing a PDP protective film which is more excellent in characteristics than the present situation, it is necessary to make film-forming conditions which emphasize certain characteristics, or to produce intermediate protective films of both characteristics.

Film-forming conditions are generally substrate temperature, pressure, process gas introduction amount, such as oxygen, Ar, hydrogen, and water, gas partial pressure, etc. in film-forming. These film formation conditions can be monitored and controlled. However, even if any film formation conditions are changed, it is insufficient to control the crystallinity of MgO and to control necessary film properties.

When a metal oxide such as MgO, SrO, CaO, or the like is irradiated with an electron beam and heated at a high temperature, steam of the metal oxide is generated, and part of the metal oxide is reduced to dissociate the metal. For example, in the case of magnesium oxide (MgO), the reaction (2MgO → 2Mg + O ₂ ) which Mg dissociates when an electron beam is irradiated occurs.

When water is introduced when the metal oxide is evaporated, the water is decomposed by the electron beam and hydrogen as a reducing agent is generated. Therefore, the reduction reaction of the metal oxide (MgO + H ₂ → Mg + H ₂ O) proceeds at a lower temperature. Even if the electron beam power is the same, the amount of reduction increases.

If oxygen or water is present when irradiating the electron beam, the dissociated metal reacts with oxygen and water to form a metal oxide (Mg + O ₂ → 2MgO, Mg + H ₂ O → MgO + H ₂ ).

The inventors have found that the oxidized oxide is incorporated into the protective film after at least a part of the metal oxide is once dissociated, rather than the protective film being formed by vapor of the metal oxide vaporized without dissociation. It discovered that film density became high.

As a result of further investigation by the present inventors, in order to dissociate a metal oxide, it was found that what is necessary is just to irradiate an electron beam so that water may be introduce | transduced into a vacuum chamber and the film-forming rate will be 40 nm / sec or more.

When the metal is oxidized to a low energy state (oxide), light of a specific wavelength is emitted. For example, the emission light when Mg is oxidized has a characteristic peak at wavelength 285.2 nm and 280.2 nm, and the emission light when Sr is oxidized has a characteristic peak at wavelength 242.8 nm and 256.9 nm.

Since the magnitude (intensity) of the peaks at these specific wavelengths increases as the amount of metal oxidized increases, the measurement of the emission intensity of the specific wavelength determines how much the metal oxide dissociates and oxidizes again. It can be seen whether or not the atmosphere containing is sufficient to dissociate and re-oxidize the metal oxide.

The present invention made on the basis of this knowledge, the metal panel disposed in the evaporation source is heated while introducing oxygen into the vacuum chamber to generate the vapor of the metal oxide, the first panel having the electrode disposed on the surface is the vacuum After conveying by the conveyance path in a tank, passing the film-forming position facing the said evaporation source, and forming the protective film which consists of a thin film of a metal oxide on the said electrode, the said 1st panel is bonded together with a 2nd panel, And a plasma display panel for manufacturing a plasma display panel in which the protective film is exposed to plasma, wherein water is introduced into the vacuum chamber so that the introduced volume per unit time is equal to or greater than the introduced volume per unit time of oxygen. While the first panel is stopped at the deposition position, the deposition rate of the protective film is 40 It is a manufacturing method of the plasma display panel which conveys a said 1st panel, evaporating the said metal oxide so that it may become nm / sec or more.

This invention arrange | positions the 1st panel in which the electrode was arrange | positioned on the surface in the film-forming position which faces the evaporation source in a vacuum chamber, heats the metal oxide arrange | positioned at the said evaporation source, introducing oxygen in the said vacuum chamber, A plasma display in which a vapor of a metal oxide is generated, a protective film made of a thin film of metal oxide is formed on the electrode of the first panel, and then the first panel is bonded to a second panel to expose the protective film to plasma. A method of manufacturing a plasma display panel for manufacturing a panel, wherein the deposition rate of the protective film is 40 nm while introducing water in the vacuum chamber so that the introduced volume per unit time is equal to or greater than the introduced volume per unit time of oxygen. It is a manufacturing method of the plasma display panel which evaporates the said metal oxide so that it may become more than / second.

The present invention is a method of manufacturing a plasma display panel, which is a method of manufacturing a plasma display panel in which the metal oxide is irradiated with an electron beam.

The present invention is a method of manufacturing a plasma display panel, wherein the total pressure of the vacuum chamber is set to a pressure exceeding 1 × 10 ⁻¹ Pa to generate a plasma of the metal oxide.

The present invention is a method of manufacturing a plasma display panel, wherein the metal oxide is MgO.

The present invention is a method of manufacturing a plasma display panel, wherein the metal oxide contains MgO and is a method of manufacturing a plasma display panel in which one or both of SrO and CaO are added.

The present invention relates to a method of manufacturing a plasma display panel, wherein, when evaporating the metal oxide, the light emission intensity of light emitted in the vacuum chamber is measured, and the metal oxide is evaporated so that the measurement value of the light emission intensity becomes a preset value. It is a manufacturing method of the plasma display panel which changes the output of a heating apparatus.

The present invention relates to a method of manufacturing a plasma display panel, wherein when the metal oxide is evaporated, the emission intensity of light emitted in the vacuum chamber is measured, and the irradiation area of the electron beam is adjusted so that the measurement value of the emission intensity is a preset value. It is a manufacturing method of the plasma display panel which changes.

The present invention provides a vacuum chamber, a heating device for heating an evaporation source disposed in the vacuum chamber, a vapor deposition material disposed in the evaporation source, a water inlet for introducing water into the vacuum chamber, and introducing oxygen into the vacuum chamber. A film forming apparatus for a protective film having an oxygen inlet, comprising: a measuring device for measuring the light emission intensity of light generated inside the vacuum chamber; and a control device connected to the measuring device and the heating device; It is a film-forming apparatus comprised so that output of the said heating apparatus was changeable based on the light emission intensity transmitted from an apparatus.

This invention is a film-forming apparatus, The said heating apparatus is an electron gun, The said control apparatus is a film-forming apparatus which changes the irradiation area of the electron beam emitted from the said electron gun.

The present invention provides a film forming apparatus, comprising a conveying apparatus for conveying a film forming object along a conveying path inside the vacuum chamber, wherein the film forming object faces the evaporation source while moving the conveying path. It is a film-forming apparatus which is closer to the said evaporation source than the oxygen introduction port and is farther from the said conveyance path | route.

The present invention provides a film forming apparatus, comprising: a substrate holder for holding a substrate at a position facing the evaporation source inside the vacuum chamber, wherein the water inlet is closer to the evaporation source than the oxygen inlet and is held by the substrate holder. It is a film-forming apparatus located in the position far from the said board | substrate.

This invention is comprised as mentioned above, and the protective film formed into a film has favorable crystal orientation and high film density. If the crystal orientation is good, the (111) peak strength of the protective film is high, and if the film density is high, the sputter resistance is improved, and the film thickness of the protective film can be reduced. For example, if the (111) peak intensity is 40% high and the film density is high, the required film thickness can be reduced by 20% to 50%.

In order to reliably oxidize the dissociated metal, the amount of water introduced is equal to or greater than that of oxygen.

Although the introduction amount of water and oxygen may be prescribed | regulated by the partial pressure in a vacuum chamber, since water decomposes | disassembles with an electron beam, it is difficult to measure the partial pressure of water correctly. Therefore, in the present invention, the introduction volume of water and oxygen is defined as the introduction volume per unit time (sccm) instead of the partial pressure.

Since the crystal orientation is good, the secondary electron emission of the protective film is high. Due to the high filling rate (membrane density), the sputtering resistance of the protective film is good, the secondary electron emission is high, and the sputtering resistance of the protective film is good, so that the lifetime of the PDP is long and the film thickness can be reduced. Can be thinned. By thinning, the deposition material is saved, and the panel cost is also reduced. Since the film formation speed is faster than the conventional one, not only the manufacturing time of the PDP is shortened, but also there is less possibility that impurities such as CO and CO ₂ are mixed. By monitoring the emission wavelength and feeding back the power of the electron gun, the MgO film quality can be stabilized.

1 is a schematic perspective view for explaining an example of a PDP;
2 is a cross-sectional view showing an example of the film forming apparatus of the present invention.
3 is a graph showing the relationship between the (111) strength and the filling rate.
4 is a graph showing the relationship between the amount of water introduced and the (111) half-value width.
5 is a graph showing the relationship between the luminescence intensity and the (111) peak intensity.
6 is a graph showing the relationship between the wavelength of emitted light and the luminescence intensity (Example)
7 is a graph showing the relationship between the wavelength of emitted light and the emission intensity (comparative example)
8 is a graph showing the relationship between EB current and luminescence intensity (Comparative Example)
9 is an electron micrograph of a protective film formed by introducing water;
10 is an electron micrograph of a protective film formed without introducing water;

Carrying out the invention  Best form for

Reference numeral 1 in FIG. 1 shows an example of the plasma display panel.

This plasma display panel 1 has first and second panels 10 and 20.

The 1st panel 10 has the 1st glass substrate 11, and the sustain electrode 15 and the scanning electrode 16 are arrange | positioned at the surface of the 1st glass substrate 11, respectively (1 in FIG. City by city).

The sustain electrodes 15 and the scan electrodes 16 are alternately arranged at predetermined intervals. The sustain electrode 15 and the scan electrode 16 are separated from each other, and a dielectric film 12 is formed between the surface and the sustain electrode 15 and the scan electrode 16. Therefore, the sustain electrode 15 and the scan electrode 16 are insulated from each other.

On the surface of the dielectric film 12, the protective film 14 is arrange | positioned over the whole surface. Therefore, the protective film 14 is located on each sustain electrode 15 and each scan electrode 16.

The second panel 20 has a second glass substrate 21. On the surface of the second glass substrate 21, the address electrodes 25 are arranged in parallel with each other, and the address electrodes 25 are spaced apart from each other. A dielectric layer 24 (insulating layer) is disposed between the surface of the address electrode 25 and the address electrode 25, and the address electrodes 25 are insulated from each other.

The partition 23 is arranged along the longitudinal direction of the address electrode 25 between the address electrodes 25. Between the partitions 23 adjacent to each other, any one of the phosphor films (red phosphor film 22R, green phosphor film 22G, and blue phosphor film 22B) containing fluorescent dyes of different colors is formed. Each address electrode 25 is covered with the phosphor films 22R, 22G and 22B of any one color through the dielectric layer 24.

As for the 1st, 2nd panel 10 and 20, the surface in which the protective film 14 was formed, and the surface of the side in which the partition 23 was formed, oppose each other, and the sustain electrode 15 and the scanning with respect to the address electrode 25 are scanned. The electrodes 16 are bonded in a state where they are aligned so as to be perpendicular to each other, and the space between the first and second panels 10 and 20 is sealed.

The partition 23 protrudes high from the surface of the second panel 20, and its tip abuts on the surface of the first panel 10. Therefore, the space between the first and second panels 10, 20 is divided by the partition 23, and in each of the divided spaces (light emitting space 29), a mixture of encapsulated gas (for example, Ne and Xe) Gas).

Next, the process of lighting this plasma display panel 1 is demonstrated.

When a voltage is applied between the selected scan electrode 16 and the address electrode 25, write discharges (address discharges) occur in light emitting cells where these electrodes intersect, and wall charges are accumulated in the light emitting cells.

Next, an alternating voltage is applied between the selected scan electrode 16 and the sustain electrode 15 adjacent to the scan electrode 16. The protective film 14 is an MgO film mainly composed of a protective material composed of MgO, an SrO-CaO film mainly composed of a protective material composed of SrO and CaO, or an MgO-SrO film composed mainly of a protective material composed of MgO and SrO. And the like. Such a protective film 14 has a high electron emission characteristic, electrons are discharged from the protective film 14 in the light emitting cell in which wall charges are accumulated by the address discharge, sustain discharge occurs, and the encapsulation gas is converted into plasma to generate ultraviolet rays.

Since ultraviolet light is emitted from the light emitting cell where the selected scan electrode 16 and the address electrode 25 intersect, when ultraviolet light is incident on the phosphor films 22R, 22G, 22B positioned in the light emitting cell, the phosphor film ( 22R, 22G and 22B) are excited to emit visible light of any color, red, green or blue.

The first glass substrate 11 and the dielectric film 12 are each transparent. Since the protective film 14 is also comprised from transparent metal oxides, such as MgO and SrO, and the film thickness distribution is not to impair transparency by ± 5%-± 10%, the whole 1st panel 10 is made transparent. Therefore, the light (visible light) emitted from the light emitting cell is transmitted through the first panel 10 and emitted to the outside.

When a weaker voltage is applied between the selected scan electrode 16 and the sustain electrode 15 adjacent to the scan electrode 16 and a weaker discharge (erasure discharge) is generated than the sustain discharge, the light emitting space The wall charge in 29 is neutralized so that the light emitting cell is turned off.

The protective film 14 is exposed to the space between the first and second panels 10 and 20, and when the light emitting cells emit light, the protective film 14 is exposed to the plasma.

The protective film 14 is comprised from materials which are hard to be etched by plasma, such as MgO and SrO. In addition, the protective film 14 formed by the present invention is more difficult to be etched because of a high filling rate as described later, and the dielectric film 12, the sustain electrode 15, and the scan electrode 16 are formed on the protective film 14. Protected by the plasma display panel 1, the plasma display panel 1 has a longer life compared with the prior art.

Next, the film-forming apparatus of this invention used for manufacture of the plasma display panel 1 is demonstrated.

The code | symbol 3 of FIG. 2 has the vacuum chamber 32 as an example of a film-forming apparatus. The vacuum chamber 32 has the film forming chamber 34 and the material chamber 35, and the material chamber 35 is disposed below the film forming chamber 34 and is connected to the film forming chamber 34. The injection chamber 31 and the extraction chamber 33 are connected to the film formation chamber 34 via the gate valve 39.

The film-forming chamber 34 is provided with the conveying apparatus 50, The film-forming object is carried in from the input chamber 31 to the film-forming chamber 34 in the state hold | maintained by the holding means 47 (carrier), and a conveying apparatus ( By 50), it is carried out to the extraction chamber 33 through the predetermined conveyance path 51 in the film-forming chamber 34. As shown in FIG.

The material chamber 35 is connected to the film formation chamber 34 at the position just below the conveyance path 51. Inside the material chamber 35, an evaporation source 36 is disposed just below the connection point between the material chamber 35 and the film formation chamber 34. Therefore, the evaporation source 36 is located directly under the conveyance path 51, and the film-forming object faces the evaporation source 36 while moving the conveyance path 51. The evaporation source 36 has a crucible (container), and a vapor deposition material is disposed in the crucible. The deposition material here is a metal oxide.

The material chamber 35 is provided with an electron gun (electron beam generator) 41. The vacuum evacuation system 52b is connected to the vacuum chamber 32, and when the inside of the vacuum chamber 32 is made into a vacuum atmosphere and the electron gun 41 is operated, the electron beam (electron beam) 42 will be a metal oxide of the evaporation source 36. Is irradiated, and vapor of the metal oxide is released into the material chamber 35.

The restriction plate 38 is arrange | positioned in the part in which the material chamber 35 and the film-forming chamber 34 in the vacuum chamber 32 were connected.

An opening (discharge port) 37 is formed at the position just above the evaporation source 36 of the limiting plate 38, and steam passing through the discharge port 37 is discharged into the film formation chamber 34.

The film-forming object passes through the film-forming position 49 which faces the evaporation source 36 via the discharge port 37 while moving the conveyance path 51. Since the diffusion angle of the vapor | steam discharged | emitted to the film-forming chamber 34 is restrict | limited by the limiting plate 38, steam enters into the film-forming object which passes through the film-forming position 49 at a predetermined incidence angle.

A water inlet port 55 and an oxygen inlet port 56 are formed at a position between the restriction plate 38 inside the vacuum chamber 32 and the evaporation source 36 (that is, inside the material chamber 35).

The water inlet 55 and the oxygen inlet 56 are connected to a gas supply system (not shown), and from the water inlet 55 and the oxygen inlet 56, H ₂ O gas (water vapor, gas Water) and oxygen gas are introduced into the material chamber 35.

The water inlet 55 is closer to the evaporation source 36 than the oxygen inlet 56, the H ₂ O gas is exposed to the electron beam 42 to generate hydrogen, and the vapor of the metal oxide contains H ₂ containing hydrogen. Exposure to O gas causes some of the vapor to be reduced, resulting in metal dissociation.

The water inlet 55 is farther from the conveying path 51 than the oxygen inlet 56. That is, the distance between the film-forming object and the water inlet port 55 when the film-forming object approaches the water inlet 55 most is the film-forming object and oxygen introduction when the film-forming object approaches the oxygen inlet 56 most. Longer than the distance between the spheres 56.

Therefore, the vapor exposed to the H ₂ O gas is also exposed to the oxygen gas before reaching the film forming object, the dissociated metal is oxidized to become a metal oxide, and then reaches the film forming object.

When dissociated metals are oxidized, they emit light (ultraviolet). On the side wall of the material chamber 35, a window portion 44 (for example, a quartz window) that transmits the light is formed. The spectroscopic monitor 43 is arrange | positioned outside the material chamber 35. Light transmitted through the window portion 44 is incident on the light receiving portion of the spectroscopic monitor 43, and the spectroscopic monitor 43 measures the emission intensity of the incident light.

When the output from the heating device (electron gun 41) or the input power per unit area to the metal oxide is made constant to increase the irradiation area of the electron beam 42, the amount of evaporation of the metal oxide per unit time is increased, and the deposition rate is increased. Rise, and the light emission intensity also increases. The electron gun 41 and the spectroscopic monitor 43 are connected to the control device 45. The measurement of the luminescence intensity is transmitted to the control device 45.

The relationship between the luminescence intensity and the film formation speed is examined and the relationship is set in the control device 45. When the desired film formation speed is set in the control device 45, the control device 45 changes the irradiation area of the electron gun 41 so that the film formation speed becomes a set value in contrast to the set relationship of the measured value of the light emission intensity.

The process of forming a protective film using this film-forming apparatus 3 is demonstrated.

First, by a preliminary test, the protective film is formed under the same conditions (type of metal oxide, film formation pressure, heating temperature, conveyance speed, etc.) when the protective film is actually formed, and per unit time when the film forming object is stopped at the film formation position. The relationship between the film thickness growth amount (static film formation rate) and the emission intensity of a specific wavelength when the metal oxide evaporates is obtained.

The static film forming speed is determined in the range of 40 nm / sec or more, and the relationship between the determined static film forming speed and the preliminary test is set in the control device 45.

The injection chamber 31, the extraction chamber 33, and the vacuum chamber 32 are evacuated by the vacuum exhaust systems 52a-52c, and the vacuum atmosphere of a predetermined pressure is formed. 1st panel 10 in the state in which the electrode (holding electrode 15, the scanning electrode 16), and the dielectric film 12 were formed in the 1st glass substrate 11 is made into a film-forming object, and is hold | maintained to the holding means 47 It is hold | maintained and carried in to the input chamber 31.

The heating means 59 is arrange | positioned inside the input chamber 31 and the film-forming chamber 34, and it carries in to the film-forming chamber 34 after heating the 1st panel 10 to predetermined temperature.

Particulate metal oxide is disposed in the evaporation source 36. The introduction amount of water (water vapor) and oxygen can be controlled by a flow control device (mass flow controller) (not shown), and the electron beam is introduced while introducing water and oxygen so that the introduction volume per unit time of water is larger than the introduction volume per unit time of oxygen. 42) to generate vapor of the metal oxide.

When the 1st panel 10 is conveyed in the conveyance path 51 so that the surface of the side in which the sustain electrode 15 and the scanning electrode 16 were formed may face downward, and passes through the position which faces the evaporation source 36, Vapor of a metal oxide reaches the sustain electrode 15 and the scanning electrode 16 (here, the surface of the dielectric film 12), and a thin film of the metal oxide (protective film 14) is formed.

The control apparatus 45 changes the irradiation area of the electron beam 42 so that the measured value of light emission intensity may be set value, measuring light emission intensity every predetermined time, or continuously measuring light emission intensity, and forming static film of the protective film 14 The speed is at a predetermined speed of 40 nm / second or more. Since the static film formation rate is 40 nm / sec or more and water is introduced in a larger amount than oxygen, the protective film 14 is oriented in the (111), and the filling rate exceeds 82%.

When the end of the conveyance direction of the 1st panel 10 reaches the film-forming position 49, and the stay time which one end takes to pass through the film-forming position 49 is multiplied by the static film-forming speed, it is a roughly protective film 14 ) Becomes the film thickness. In other words, when the film thickness of the protective film 14 is determined, the value obtained by dividing the static film forming speed by the film thickness is the stay time.

After the conveyance path 51 is moved, the 1st panel 10 of the state in which the protective film 14 was formed is carried out to the take-out chamber 33, and after cooling, it is carried out to the film deposition apparatus 3 outside.

When the first panel 10 taken out and the above-mentioned second panel 20 are bonded together and the enclosed gas is arrange | positioned between the 1st, 2nd panels 10 and 20, the plasma display panel 1 of FIG. Obtained.

As mentioned above, although the case where the protective film 14 was formed in the 1st panel 10 of 3-electrode AC type PDP was demonstrated, this invention is not limited to this, The protective film 14 is only in the 2nd panel 20 only. The film may be formed or may be formed on both of the first and second panels 10 and 20. In the case of forming the protective film 14 on the second panel 20, the protective film 14 is disposed on at least each address electrode 25.

The metal oxide used for this invention is MgO alone or a mixture of MgO and another metal oxide (either one or both of SrO and CaO).

When using a mixture of metal oxides, it is possible to control the electron gun to stabilize the film properties by measuring the luminescence intensity at the time of oxidation of the dissociated metal with respect to any one or more metal oxides in the mixture.

When using a mixture of metal oxides, in conventional methods (e.g., crystal oscillation deposition controllers, CRTM), it is very difficult to monitor a plurality of materials, but by monitoring the intensity of a specific wavelength, It is possible to control the characteristic of the protective film which consists of a kind of metal oxide.

The vapor deposition material is not limited to the metal oxide, and at least one kind of additive selected from the group consisting of Ca, Al, Si, Mn, Eu, and Ti may be added based on the metal oxide described above.

When the metal oxide is evaporated using the plasma gun, the metal oxide is excessively dissociated, and there is a fear that unoxidized metal is mixed in the protective film. Since unoxidized metal, especially Mg, has high ignition property, in the present invention, the metal oxide is evaporated by the electron beam 42 using the electron gun 41. The electron gun 41 is not particularly limited, but in view of the controllability and stability of the evaporation rate, a pierce-type electron gun is suitable.

If the film thickness distribution of the protective film 14 becomes uneven, the optical properties are inferior and not suitable for the first panel 10. Therefore, the film thickness distribution is ± 5% to ± 10% of the target film thickness (for example, 800 nm). The rocking waveform of the electron beam 42 is determined to be.

As mentioned above, although the case where the control apparatus 45 changed the irradiation area of the electron beam 42 and made light emission intensity into a set value was demonstrated, this invention is not limited to this, The power density of the electron gun 41 (W / Cm 2) may be changed to set the light emission intensity.

However, if the power density is increased, a dolby of a metal oxide called a splash will occur and the film-forming object will be contaminated. Therefore, in this invention, power density is made constant and light emission intensity is changed by changing an irradiation area. It is desirable to.

In FIG. 2, although the injection chamber 31 and the extraction chamber 33 were connected to the film-forming chamber 34, when the tack time is fast (short), when the time to fully heat the film-forming object before film-forming cannot be ensured, The heating chamber is provided between the input chamber 31 and the film formation chamber 34. Moreover, when time to cool the film-forming object after film-forming enough cannot be ensured, the cooling chamber is provided between the film-forming chamber 34 and the extraction chamber 33. As shown in FIG.

Although the evaporation source 36 may be stopped, you may rotate the evaporation source 36 in the plane parallel to the conveyance path 51 in the position just under the conveyance path 51.

As mentioned above, although the case where the protective film 14 was formed while conveying a film-forming object (1st panel 10) was demonstrated, this invention is not limited to this. For example, you may arrange | position a board | substrate holder in the position just above the evaporation source 36 inside the material chamber 35, hold | maintain in a substrate holder so that a film-forming object may face the evaporation source 36, and the protective film 14 may be formed into a film. In this case, the distance between the evaporation source 36 and the film forming object does not change at least while forming the protective film 14.

In the case of forming the protective film 14 without changing the distance between the evaporation source 36 and the film forming object, in order to obtain a film having a (111) crystal orientation and having a filling rate of 82% or more, the film forming object held in the substrate holder is The film thickness growth amount (ie, film formation rate) per unit time is 40 nm / sec or more, and other conditions (water and oxygen introduction amount, etc.) are the same as in the case of performing film formation while conveying the film forming object.

When the distance between the evaporation source 36 and the film forming object is not changed, the oxygen inlet 56 is arranged closer to the film forming object of the substrate holder than the water inlet 55, and the water inlet 55 is introduced with oxygen. It is arranged closer to the evaporation source 36 than the sphere 56.

When the substrate holder is rotated to rotate the film forming object in a plane facing the evaporation source 36, the film thickness distribution of the protective film 14 becomes uniform.

If the purity of the water to be introduced into the vacuum chamber is poor, the film quality deteriorates, so that the water is preferably pure water (0.01 or less absorbance of wavelength 210 nm to 400 nm, 5 ppm or less nonvolatile). In particular, the inclusion of an organic substance in water causes a deterioration in discharge characteristics. Therefore, the total organic carbon amount is preferably 4 ppb or less.

Although the installation place of the water inlet port 55 is not specifically limited, If it directly faces the vapor outlet port (for example, the opening of a crucible) of the evaporation source 36, a metal oxide will precipitate and the water inlet port 55 will be clogged. There is concern. Therefore, it is preferable that the water inlet 55 does not face the vapor outlet, or a shield is disposed between the water inlet 55 and the evaporation source 36.

Moreover, even if a large amount of water is introduced into the vacuum chamber, if the film formation rate is the same as before (less than 40 nm / sec), the peak intensity of the (111) crystal orientation is small and does not reach the practical level. It is essential to introduce water into the bath and to make the deposition rate 40 nm / second or more (more preferably 140 nm / second or more).

The amount of water introduced is not particularly limited as long as it is larger than the amount of oxygen introduced, but 200 sccm or more is preferable.

The internal pressure (film formation pressure) of the vacuum chamber 32 at the time of forming the protective film 14 is not specifically limited. In case of introducing H ₂ O gas and a smaller amount of oxygen, even if the deposition pressure is higher than 5 × 10 ⁻² Pa (for example, 0.2 Pa, 0.3 Pa, etc.), the impurity concentration of the protective film (especially impurities containing C) ), Film density, (111) crystal orientation and the like do not deteriorate, and the intensity distribution of the crystal orientation is more improved than before.

If the film formation is continued, the metal oxide adheres to the inner wall surface of the vacuum chamber 32 and causes dusting, so the vacuum chamber 32 needs to be cleaned regularly. When the film-forming pressure was low below 5 * 10 <^-2> Pa, it was necessary to vacuum-exhaust the inside of the vacuum chamber 32 for a long time (5-6 hours) after cleaning. If the film formation pressure is 5 × 10 ⁻² Pa or more, more preferably 1 × 10 ⁻¹ Pa or more, it is not necessary to evacuate the inside of the vacuum chamber 32 for a long time after cleaning, so that the return after maintenance is quick.

Example

<Crystal Orientation and Film Density>

The relationship between the intensity | strength and filling rate of (111) of the protective film formed while introduce | transducing water so that it may become larger than the introduction amount of oxygen in the material chamber 35 using the said film-forming apparatus 3 is shown to E1-E4 of FIG. Representative film forming conditions are shown in Table 1 below, and the analysis results of water (H ₂ O gas) introduced into the material chamber 35 are shown in Table 2 below.

Table 1: Deposition Conditions Board Glass plate for PDP Evaporation material MgO single crystal Substrate temperature 250 ℃ Oxygen introduction amount 300 sccm H ₂ O Introduction 500 sccm Electron gun power 7.5 kW × 2 Dynamic Rate (Dynamic Deposition Speed) 1132 nmm / min Static Rate (Static Deposition Rate) 40 nm / sec Protective film thickness 800 nm

Table 2: Pure water (ultra pure water for liquid chromatograph / mass spectrometer) Absorbance (wavelength 210nm ~ 400nm) 0.01 or less Nonvolatile matter 5 ppm or less pH 5.0 to 7.5 Full Organic Carbon (TOC) 4 ppb or less

The relationship between the (111) strength and the filling rate of the protective film formed by introducing only oxygen without introducing H ₂ O is shown in C1 to C3 in FIG. 3.

About the protective film of an Example and a comparative example, the diffraction intensity and refractive index of (111) orientation were measured, and the filling rate (film density) was calculated | required from the refractive index. The refractive index was measured with an ellipsometer. When the refractive index is n, the filling rate (film density) is p, the space refractive index is nv, and the bulk refractive index is ns, the refractive index n is expressed by the following equation (1).

(1). n = (1-p) nv + pns

Since the refractive index nv of space is normally 1 in air and the refractive index of bulk is 1.73 in case of MgO single crystal, the filling rate p of MgO is calculated | required by following formula (2) from refractive index.

(2). p = (n-1) /0.73

As can be seen from FIG. 3, the filling rate of the (111) MgO film having a peak intensity of 3000 CPS was 88.7% in the comparative example, while it was 90.7% in the MgO film of the example, and improved by about two points.

Moreover, while the (111) intensity | strength of the MgO film | membrane for obtaining 90% of a filling rate was 2450 CPS of the comparative example, the Example improved to about 40% or more by 3500 CPS. From the above result, it turns out that the protective film formed by this invention has both high film density (fill rate) and high (111) orientation.

<Relationship between the amount of water introduced and (111) half value width>

The introduction amount of water was changed and the half value width of the (111) orientation peak was measured. The relationship between the half width and the amount of water introduced is shown in FIG. 4. 4 represents the water introduction amount (sccm), and the vertical axis represents the half value width, and the smaller the half value width, the better the crystallinity. According to the present invention, the half width was improved by about 40% compared with the conventional one, and it was confirmed that the protective film formed by the present invention had good crystallinity.

As mentioned above, it turns out that the crystallinity of a protective film improves significantly compared with the past, by increasing the evaporation rate of MgO, making a static film forming speed | rate faster, and forming into a film while introducing water.

<Relationship between luminescence intensity and (111) peak intensity>

The protective film was formed by evaporating MgO with a large irradiation area without changing the power density of the electron gun. The luminescence intensity of wavelength 285.2 nm at the time of evaporating MgO was measured with the spectral monitor manufactured by Otsuka Electronics Co., Ltd. The (111) peak intensity of the formed protective film was calculated | required. The relationship between luminescence intensity and peak intensity is shown in FIG.

As can be seen from FIG. 5, it can be seen that as the light emission intensity increases, the (111) peak intensity increases, and the film quality of the protective film is improved.

<Luminescence spectrum>

The wavelength and emission intensity of the emitted light when the protective film was formed under the film forming conditions of Table 1 were measured. The measurement result is shown in FIG. As a comparative example, the wavelength and emission intensity of the emitted light when the protective film was formed under the film forming conditions of Table 1 were measured except that the amount of water introduced was zero. The result is shown in FIG.

6 and 7, as is clear, in FIG. 6 in which water was introduced, two peaks (wavelengths 285.2 nm and 280.2 nm) derived from the oxidation reaction of Mg were found. In FIG. 7 in which water was not introduced, Two peaks could not be identified.

The result of having measured the luminescence intensity of wavelength 285.2 nm by increasing the power input to an electron gun without introducing water, is shown in FIG. It can be seen from FIG. 8 that the light emission intensity is increased when the input power is increased, but the light emission intensity is extremely lower than when water is introduced, and when the water is introduced, the metal oxide dissociates at a low input power and recombines. Able to know.

<Comparison of the properties of the protective film with or without water introduction>

9 and 10 show electron micrographs of the protective film when water is introduced and the protective film when water is not introduced. 9 and 10 show the gap between the MgO columnar crystals and the MgO columnar crystals. The smaller the gap between the columnar crystals, the less the adsorption amount of impurity gas and the more difficult the etching.

9 and 10 show that the protective film in FIG. 9 has a small gap between the columnar crystals, and the introduction of water makes it difficult to adsorb impurity gas and hardly etch.

In addition, when the relationship between the dynamic film forming speed and static film forming speed shown in the said Table 1 is demonstrated, a dynamic film forming speed is a unit which shows the film forming speed at the time of carrying out film-forming, carrying a board | substrate, and a board | substrate moves for 1 minute for 1 minute. The film thickness that is formed during the festival. When the dynamic film formation rate is multiplied by a predetermined coefficient, the static film formation rate when the substrate is fixed to the evaporation source is obtained.

The coefficient when converting the static deposition rate is different depending on the deposition apparatus used. In this case, it is 2.12. If the static deposition rate is Rs and the dynamic deposition rate is Rd, the static deposition rate Rs is expressed by the following equation (3). Represented by

(3). Rs (μs / sec) = Rd (μm / sec) × 2.12

One… Plasma display panel
3 ... Deposition device
10... First panel
14... Shield
15, 16... Electrode (holding electrode, scan electrode)
32... Vacuum
36... Evaporation source
41... Electron gun
51 ... Bounce path
55... Water inlet
56... Oxygen inlet

Claims (12)

While introducing oxygen into the vacuum chamber, the metal oxide disposed in the evaporation source is heated to generate steam of the metal oxide,
After the 1st panel in which the electrode was arrange | positioned at the surface is conveyed in the conveyance path | route in the said vacuum chamber, passes through the film-forming position facing the said evaporation source, and forms the protective film which consists of a thin film of a metal oxide on the said electrode,
A method of manufacturing a plasma display panel in which the first panel is bonded to a second panel to manufacture a plasma display panel in which the protective film is exposed to plasma.
In the vacuum chamber, while introducing water such that the introduced volume per unit time is equal to or greater than the introduced volume per unit time of oxygen,
A method of manufacturing a plasma display panel, wherein the first panel is conveyed while evaporating the metal oxide so that the deposition rate of the protective film when the first panel is stopped at the deposition position is 40 nm / sec or more. The first panel having the electrodes arranged on the surface is disposed at the film formation position facing the evaporation source inside the vacuum chamber,
After introducing oxygen into the vacuum chamber, the metal oxide disposed in the evaporation source is heated to generate steam of the metal oxide, and a protective film made of a thin film of metal oxide is formed on the electrode of the first panel.
A method of manufacturing a plasma display panel in which the first panel is bonded to a second panel to manufacture a plasma display panel in which the protective film is exposed to plasma.
In the vacuum chamber, while introducing water such that the introduced volume per unit time is equal to or greater than the introduced volume per unit time of oxygen,
And evaporating the metal oxide so that the deposition rate of the protective film is 40 nm / second or more. The method according to claim 1 or 2,
A method of manufacturing a plasma display panel, wherein the metal oxide is irradiated with an electron beam. The method according to any one of claims 1 to 3,
A method of manufacturing a plasma display panel, wherein steam of the metal oxide is generated by setting the total pressure of the vacuum chamber to a pressure exceeding 1 × 10 ⁻¹ Pa. The method according to any one of claims 1 to 4,
And said metal oxide is MgO. The method according to any one of claims 1 to 4,
The metal oxide contains MgO, and either or both of SrO and CaO is added. The method according to any one of claims 1 to 6,
When evaporating the metal oxide, the emission intensity of the light emitted in the vacuum chamber is measured,
The output method of the heating apparatus which evaporates the said metal oxide is changed so that the measured value of the luminescence intensity may be a preset value. The method according to any one of claims 3 to 7,
When evaporating the metal oxide, the emission intensity of the light emitted in the vacuum chamber is measured,
And the irradiation area of the electron beam is changed so that the measurement value of the light emission intensity becomes a preset value. A vacuum chamber, an evaporation source disposed in the vacuum chamber, a heating device for heating the vapor deposition material disposed in the evaporation source, a water inlet for introducing water into the vacuum chamber, and an oxygen inlet for introducing oxygen into the vacuum chamber. As a film forming apparatus of a protective film to have,
A measuring device for measuring the emission intensity of light generated inside the vacuum chamber;
It has a control apparatus connected to the said measuring apparatus and the said heating apparatus,
The control apparatus is configured to be able to change the output of the heating apparatus based on the light emission intensity transmitted from the measuring apparatus. The method of claim 9,
The heating device is an electron gun, and the control device changes the irradiation area of the electron beam emitted from the electron gun. The method according to claim 9 or 10,
It has a conveying apparatus which conveys a film-forming object along the conveyance path inside the said vacuum chamber,
The deposition object is to face the evaporation source while moving the conveyance path,
The film introduction apparatus, wherein the water inlet is closer to the evaporation source than the oxygen inlet and is farther from the conveying path. The method according to claim 9 or 10,
A substrate holder for holding the substrate at a position facing the evaporation source inside the vacuum chamber,
The film introduction apparatus, wherein the water inlet is closer to the evaporation source than the oxygen inlet and is far from the substrate held by the substrate holder.

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