JP2000011888A - Plasma display panel and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: An MgO film for suppressing deterioration of discharge characteristics due to an MgO film of a plasma display panel and for preventing cracking of the MgO film during a panel assembling process (sealing process). The content of moisture and carbon dioxide in the interior is reduced, and the film is made denser. A substrate on which an MgO film is formed is heated to 300 ° C.
A heat treatment is performed at a temperature of about 400 ° C., and the MgO film is densified by heating and degassing, and then the front plate and the back plate are assembled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma display panel and a method of manufacturing the same, and more particularly, to a protective film for a dielectric layer on a display electrode and a method of forming the same.

[0002]

2. Description of the Related Art One example of a plasma display panel is as follows.
FIG. 7 and FIG. FIG. 7 is a perspective view showing the structure of the plasma display panel, but the front plate 1 is shown separated from the back plate 2 and the discharge space 3 for easy viewing.

A front plate 1 is provided on a front glass substrate 4 with an IT
A display electrode 6 made of a transparent conductive material such as O (Indium Tin Oxide), a bus electrode 7, a dielectric layer 8 made of low-melting glass or the like, and a protective film 9 made of a material such as MgO (magnesium oxide). It has a formed structure. The back plate 2 has an address electrode 10 on a back glass substrate 5,
It has a structure in which a barrier rib 11 and a phosphor layer 12 are formed. A discharge space 3 is formed between the front plate 1 and the back plate 2 by laminating the front plate 1 and the back plate 2 such that the display electrodes 6 and the address electrodes 10 are substantially orthogonal to each other.

FIG. 8 is a cross-sectional view of a main part of the plasma display panel shown in FIG. 7, which is parallel to the address electrodes 10, and makes the cross-sectional structure of the panel easier to understand.
The protection film 9 made of the MgO film shown in FIGS. 7 and 8 is provided to protect the dielectric layer 8 from ion bombardment at the time of discharge. Lowered to facilitate driving. Such MgO
Basically, the film is formed by an evaporation method in which a film material is evaporated by, for example, electron beam heating or the like, and deposited on the surface of the dielectric layer in the form of crystal growth.

[0005] The structure and manufacturing method of such a general plasma display panel are described in, for example, pages 202 to 202 of the flat panel display 1997 issue (edited by Nikkei BP, Nikkei Microdevices Separate Volume, 1996).
Page 07.

[0006]

However, in the above-described plasma display panel according to the prior art, there are discharge cells having a high discharge start voltage and a low frequency of light emission, or the discharge start voltage becomes high when the operation time is prolonged. Sometimes became unstable. The reason for this is not completely clear, but the protective film 9 of the dielectric layer 8
Is likely to greatly affect the discharge characteristics because it contacts the discharge space.

[0007] In the sealing step of the front plate 1 and the back plate 2, cracks may occur in the MgO film provided as the protective film 9.

[0008] MgO used as a protective film 9 for the dielectric layer 8
The film quality of the film is hardly considered except for the crystal orientation, visible light transmittance, and surface morphology. However, it is considered that the MgO film formed by the electron beam evaporation method in an atmosphere into which oxygen gas is introduced has a problem in film quality as shown in FIGS.

FIG. 5 shows how gas is released from the MgO film by heating. As can be seen from this figure, H ₂ O (moisture) is released at a heating temperature of 100 ° C. to 150 ° C., and CO and CO ₂ (carbon dioxide) are released at a heating temperature of around 300 ° C. Such released gas is
It is likely to affect the discharge characteristics after panel assembly and make the operation unstable.

FIG. 6 is a schematic diagram showing an M-shaped semiconductor formed on a silicon wafer.
3 shows the thermal stress behavior of the gO film. It can be seen that the film stress of the MgO film is a compressive stress and hardly changes up to a temperature of 300 ° C., but when it is higher than that, it rapidly changes to a tensile stress side. Considering that the thermal expansion coefficient of a silicon wafer is significantly smaller than that of a glass plate used for a plasma display panel, a large tensile stress is generated in an MgO film in an actual panel assembly process. Therefore, the probability that cracks occur in the MgO film increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. In order to suppress the deterioration of the discharge characteristics caused by the MgO film of the plasma display panel, water or carbon dioxide gas is added to the MgO film. It is an object of the present invention to reduce the tensile stress generated in the MgO film in order to reduce the content of and to prevent the occurrence of cracks in the MgO film during the panel assembly process (sealing process). .

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide a method of manufacturing a semiconductor device, comprising the steps of:
This is achieved by performing a heat treatment on the protective film made of a film to densify the MgO film. In particular, in order to enhance the effects of the present invention, the temperature of the heat treatment is preferably set to 300 to 400 ° C. Hereinafter, the reason will be described.

The MgO film formed by vapor deposition contains water, hydroxide, and carbonate and water and carbon dioxide components. These are, as shown in FIG.
Released as ₂ O, CO, and CO ₂ Therefore, these can be removed by performing a heat treatment prior to assembly. For the purpose of removing only water, a heat treatment at about 150 ° C. is effective, but a heating temperature of 300 ° C. or more is required to remove carbon dioxide components. However, it is not desirable to exceed the glass transition point of the low melting point glass constituting the dielectric layer 8, and the heat treatment temperature is set to 400
It is good to be below ℃. Thus, M
Since the gas emission source contained in the gO film can be eliminated,
The gas released from the inside after assembly can be significantly reduced. Further, since the film is densified by releasing the water and carbon dioxide components, the gas components newly stored thereafter are also significantly reduced.

As shown in FIG. 6, the reason why a large tensile stress is generated in the assembling process is that the film quality changes due to gas release in the heat process. Again, by performing densification by heat treatment at a temperature that does not generate large tensile stress, the thermal expansion coefficient of the MgO film can be made closer to the glass plate or dielectric layer, and the generation of tensile stress in the panel assembly process can be reduced. Therefore, the occurrence of cracks can be prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. This figure is a cross-sectional view of a main part of a manufacturing process of a plasma display panel to which the present invention is applied.

First, the manufacturing process of the front plate will be described. The front glass substrate 4 made of soda glass or the like is received (step S1), and is washed to form a SiO ₂ film (not shown). Next, an ITO film is formed by a sputtering method or the like, and is patterned by a known photoetching method to form a display electrode pattern 6 (Step S).
2). Next, a Cr / Cu / Cr laminated film is formed by a sputtering method or the like, and is patterned by a known photoetching method to form a bus electrode pattern 7 (step S3). Subsequently, a low-melting glass is applied by printing, dried and fired to form a dielectric layer 8 (step S4). Next, a seal layer (not shown) is formed by a printing method or the like (Step S5), and an MgO film is deposited by an electron beam evaporation method or the like, thereby forming a protective layer 9 having a thickness of 0.5 μm. (Step S6). Thus, the front plate 1 is completed.

Next, the manufacturing process of the back plate will be described. The back glass substrate 5 made of soda glass or the like is received (step S11), and is washed to form a SiO ₂ film (not shown). Next, a Cr / Cu / Cr laminated film is formed by a sputtering method or the like, and is patterned by a known photoetching method to form an address electrode pattern 10 (Step S12). Subsequently, a protective layer (not shown) of the address electrode 10 is formed by a printing method or the like, and then a barrier rib material is applied by a printing method or the like and dried. Then, the barrier rib 1 is formed by a known photolithography method using a dry film and a sand blast method.
1 is formed (step S13). Next, the phosphor layer 12 is applied by a printing method or the like, and is dried and fired (step S1).
4). Next, a sealing layer (not shown) is formed by a printing method or the like (Step S14), and the back plate 2 is completed.

Before the step of bonding front plate 1 and rear plate 2, heat treatment of front plate 1 is performed (step S 7).
The front plate 1 and the back plate 2 are bonded and assembled, and sealing is performed (step S21). Next, the inside of the panel is evacuated and
And a discharge gas made of Xe (step S22). Finally, aging is performed (step S23), whereby
The panel is completed.

A feature of this embodiment is that the front plate 1 is heat-treated before the front plate 1 and the rear plate 2 are assembled. The heat treatment conditions may be optimized according to the panel, but the heat treatment temperature is preferably between 300 ° C and 400 ° C. Thereby, as described above, not only the moisture but also the carbon dioxide gas source can be removed. The heat treatment time is preferably adjusted by checking the state of gas release.

The heat treatment which is the feature of the present invention
The change in the film quality of the O film will be described with reference to FIGS. FIG.
Is an infrared absorption curve of the MgO film. (A) shows absorption peaks (hydroxide, adsorbed water) related to water, and (b)
Indicates an absorption peak (carbonate) related to carbon dioxide. Compared to the conventional MgO film, the MgO film of the present invention
It can be seen that the absorption peak of the O film is significantly lower.

FIG. 3 shows a state of gas release when the MgO film according to the present invention is heated. As shown in the figure, it can be seen that the application of the present invention significantly reduced the amount of outgassing. Therefore, it is possible to shorten the evacuation time after assembling and sealing, and it is possible to prevent the discharge characteristics from being deteriorated due to the gas released from the MgO film. Furthermore, MgO
Since the film is densified by heat treatment (the film density increases and the refractive index increases), the effect of reducing the absorption of re-adhered moisture and carbon dioxide gas is also obtained.

FIG. 4 shows the temperature change of the film stress of the MgO film according to the present invention formed on a silicon wafer. Although the film stress of the MgO film according to the present invention is a tensile stress, it changes to the compression side as the temperature rises,
Even at a temperature of ° C., no large tensile stress is generated.
Although the thermal expansion coefficient of the dielectric layer 8 and the front glass substrate 4 is much larger than that of the silicon wafer, the thermal expansion between the MgO film (protective film 9) and the dielectric layer 8 and the front glass substrate 4 is achieved by applying the present invention. It can be seen from this figure that the difference in expansion coefficient can be reduced. As a result, MgO during assembly (sealing process)
Cracks in the film can be almost eliminated. In the present embodiment, the thickness of the protective layer 9 made of the MgO film is set to 0.5 μm. However, the thickness is not limited to 0.5 μm. It is practical to set in the range of 2 to 2 micrometers.

Note that the present invention is not limited to the above-described embodiment, but includes
As long as the O film is formed, a plasma display panel having any structure may be used.

[0024]

As described above, according to the present invention, outgassing from the MgO film can be suppressed as much as possible, so that deterioration of the discharge characteristics and changes over time caused by the MgO film for protecting the dielectric layer can be suppressed. In addition, the evacuation time before filling the discharge gas can be reduced. Further, since the tensile stress generated in the MgO film is reduced, the MgO film can be used during the panel assembly process (sealing process).
Cracking of the O film can be prevented.

[Brief description of the drawings]

FIG. 1 is a process flowchart showing a manufacturing process of a plasma display panel according to an embodiment of the present invention in a cross-sectional view of a main part.

FIG. 2 is an explanatory diagram showing an infrared absorption spectrum showing a decrease in the content of water and carbon dioxide in an MgO film by applying the present invention.

FIG. 3 is an explanatory view showing gas release from an MgO film according to the present invention.

FIG. 4 is an explanatory diagram showing a temperature change of a film stress of an MgO film according to the present invention.

FIG. 5 is an explanatory view showing gas release from an MgO film according to a conventional method.

FIG. 6 is an explanatory diagram showing a temperature change of a film stress of an MgO film according to a conventional method.

FIG. 7 is a perspective view showing an example of a plasma display panel.

8 is a cross-sectional view of a main part of the plasma display panel shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 3 Discharge space 4 Front glass substrate 5 Back glass substrate 6 Display electrode (transparent electrode) 7 Bus electrode 8 Dielectric layer 9 Protective layer (MgO film) 10 Address electrode 11 Barrier rib 12 Phosphor layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuyuki Ushifusa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside of Hitachi, Ltd.Production Technology Research Institute (72) Inventor Akira Yabushita 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Address: Hitachi, Ltd., Production Technology Laboratory (72) Inventor: Makoto Fukushima 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd .: Production Technology Laboratory (72) Inventor: Naoto Yanagihara Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa 292 Hitachi-machi, Ltd.Information Media Division of Hitachi, Ltd. (72) Inventor Shigeaki Suzuki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Ltd.Information Media Division of Hitachi, Ltd. (72) Kazuhiro Mochida Yokohama, Kanagawa Prefecture 292 Yoshida-cho, Totsuka-ku, Ichiba, Japan None (reference) 5C027 AA07 5C040 BB04 DD11

Claims (4)

[Claims] 1. A front plate on which a display electrode for generating a main discharge for performing a display is formed, and a rear plate on which an address electrode for selecting a display cell is formed are arranged parallel to and opposed to each other, A plasma display panel comprising a plurality of discharge cells having discharge spaces separated by barrier ribs between the front plate and the rear plate, and a phosphor screen showing at least one or more luminescent colors is formed in the discharge cells. In the above, a dielectric layer transparent to visible light is formed so as to cover the display electrode, and a heat-treated MgO-based protective film is formed on the dielectric layer. A plasma display panel characterized by the following. 2. The plasma display panel according to claim 1, wherein a heat treatment temperature of the protective film is set to 300 to 400 ° C. 3. The plasma display panel according to claim 1, wherein the heat-treated protective film containing MgO as a main component has a thickness of 0.2 to 2 micrometers. Plasma display panel. 4. A manufacturing method for manufacturing a plasma display panel according to claim 1, wherein the front plate and the back plate are attached to each other.
A method for manufacturing a plasma display panel, wherein a front plate on which a protective film containing MgO as a main component is formed is heat-treated.