JP4055479B2 - Method for manufacturing plasma display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a plasma display device, and more particularly to a substrate cleaning process for a front plate.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a typical plasma display device as a display device suitable for thinness has a configuration shown in FIG. 3 , for example. The plasma display device includes a front plate and a back plate that are arranged to face each other. A transparent electrode 3 and a bus electrode 4 as display electrodes, a black stripe 5, a dielectric layer 6, and a dielectric protective layer 7 made of MgO are sequentially formed on the front substrate 1 serving as a front plate substrate. Yes. An address electrode 8 and a base dielectric layer 9 are formed on the back substrate 2 serving as a back plate substrate, and a partition wall 10 is formed thereon. A phosphor layer 11 is applied between the barrier ribs 10.
[0003]
A discharge gas 12 (for example, a mixed gas of Ne—Xe) is sealed between the front plate and the back plate at a pressure of 53200 Pa (400 Torr) to 79800 Pa (600 Torr). By discharging the discharge gas 12 between the display electrodes to generate ultraviolet rays and irradiating the phosphor layer 11 with the ultraviolet rays, image display including color display becomes possible. A plasma display device is formed by attaching a drive circuit to the plasma display panel configured as described above.
[0004]
In the actual product, the front plate and the back plate are arranged with the address electrodes 8, the display electrodes 3, 4 and the black stripe 5 facing each other so that their longitudinal directions are orthogonal to each other . For convenience, the front plate is shown rotated by 90 ° with respect to the back plate.
[0005]
Next, a method for manufacturing the front plate will be described. First, the front substrate 1 serving as a substrate of the front plate is formed of a glass material that can withstand a heat treatment process included in the formation process of the bus electrode 4, the black stripe 5, the dielectric layer 6, and the like, and is generally performed by a float method. The formed high strain point glass is used. The front substrate 1 is cleaned by a method such as brush cleaning or ultrasonic cleaning using an alkali cleaning solution containing at least a surfactant, and then formed by sputtering or the like using a material such as ITO or SnO _2. The transparent electrode 3 is formed by patterning by etching or the like. Note that the substrate on which the transparent electrode 3 is formed may be washed in the same manner. Next, a photosensitive printing paste or the like containing Ag as a main component is formed by screen printing or the like, patterned by exposure, and then fired to form the bus electrode 4. Next, a photosensitive printing paste or the like that is black using black pigment, RuO, or the like as a pigment is formed into a film by a screen printing method or the like, patterned by exposure, and then baked to form a black stripe 5. Next, a paste containing PbO—B ₂ O ₃ —SiO ₂ glass as a main component is formed into a film by a method such as a screen printing method or a die coating method, and baked to form the dielectric layer 6. Next, MgO is deposited by a method such as sputtering to form the dielectric protective layer 7 to complete the front plate.
[0006]
Next, a method for manufacturing the back plate will be described. The back substrate 2 serving as the substrate of the back plate is also formed by the same method as the front substrate 1. The method for cleaning the back substrate 2 is also performed in the same manner as the method for cleaning the front substrate 1. Next, a photosensitive printing paste or the like containing Ag as a main ingredient is formed by screen printing or the like, patterned by exposure, and then baked to form the address electrodes 8. Next, a paste containing PbO—B ₂ O ₃ —SiO ₂ glass as a main component is formed into a film by a method such as a screen printing method or a die coating method, and baked to form the base dielectric layer 9.
[0007]
Next, a paste mainly composed of an aggregate such as Al ₂ O ₃ and glass frit is formed by a printing method or a die coating method, and a resist is formed in a desired partition pattern thereon, and then unnecessary by a sand blast method or the like. Remove the part and pattern and fire, or form a photosensitive paste mainly composed of aggregates such as Al ₂ O ₃ and glass frit by printing method or die coating method to form an exposure mask with a desired pattern The barrier ribs 10 are formed by a method such as baking after patterning by exposing to light and developing. Next, red, green, and blue phosphor pastes are sequentially applied between the barrier ribs 10 by a printing method, a dispenser method, a line jet method, or the like, and baked to form the phosphor layer 11 to complete the back plate. To do.
[0008]
[Problems to be solved by the invention]
However, the high strain point glass formed by the float method used for the front plate of the plasma display device has an Sn layer formed on the glass surface due to its manufacturing method. The reason is that in the float process, a molten glass material is poured into a high-temperature Sn bath, stretched into a plate with a desired thickness on the Sn bath, cooled, and then cut into a desired size to form a glass substrate. Therefore, Sn diffuses not only to the surface in contact with the Sn bath but also to the opposite surface, and an Sn layer is formed on the surface of the glass substrate. The film thickness of the Sn layer reaches about 5 μm at the maximum on the surface opposite to the surface in contact with the Sn bath (film formation surface).
[0009]
When Ag is present on the glass substrate on which this Sn layer is formed and a heat treatment process is applied, Ag colloids due to the oxidation-reduction reaction of Sn and Ag, and further aggregates to change the color of the substrate to yellow (hereinafter referred to as “yellow”). This phenomenon is called yellowing). When a yellowed substrate is used as the plasma display device, the displayed image not only increases yellowishness but also causes a decrease in luminance. Therefore, it is necessary to avoid yellowing.
[0010]
As means for avoiding yellowing, a method of removing the Sn layer on the surface of the glass substrate by a method such as mechanical polishing or chemical etching (for example, JP-A-11-246238), or a method of providing a protective film on the surface of the substrate (for example, JP-A-Hei. 10-302648) and the like have been proposed. However, since mechanical polishing and passivated layers have many disadvantages in terms of cost because of the large size of the equipment and the inability to process a large number of sheets, chemical etching that can process a large number of sheets simultaneously is considered advantageous in terms of cost. It is done.
[0011]
However, in the case of chemical etching, if some foreign matter adheres to the surface of the processing substrate as shown in FIG. 4 (A), the foreign matter 13 or 14 becomes a mask, and the etching becomes uneven as shown in FIG. 4 (B) . There is a problem that a portion that is not etched occurs. In FIG. 4 , 15 and 16 are Sn layers.
[0012]
Incidentally, the foreign substances 13 and 14 that can be a mask include an organic type and an inorganic type, but it is an organic substance that is difficult to remove. Since inorganic foreign matter is only physically adsorbed, it is easy to remove by ordinary cleaning, but organic foreign matter may be adsorbed not only physically but also chemically. For this reason, it is difficult to remove completely by ordinary cleaning. A common method for removing organic substances is ashing with ozone. This is a method of generating ozone gas by plasma to remove organic substances. However, since it is carried out in a dry atmosphere, there is a possibility that it will be reattached and it will be difficult to remove completely.
[0013]
The present invention has been made in view of these problems, and provides a high-quality plasma display device without yellowing by effectively removing organic substances and etching a substrate surface.
[0014]
[Means for Solving the Problems]
In order to achieve this object, according to the present invention, when a front plate of a plasma display device is manufactured, an organic substance adhering to the substrate is removed using a solution containing ozone in a sealed atmosphere, and then the substrate surface is etched. It has a cleaning / etching process.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
That is, according to the first aspect of the present invention, when a front plate of a plasma display device is manufactured, after forming a transparent electrode, an organic substance adhered on the substrate using a solution containing ozone in a sealed atmosphere. After removing the substrate, a cleaning / etching process for etching the substrate surface is performed, and then the bus electrode is formed. By removing the organic material and then etching the substrate surface, the organic material is etched without removing the organic material. Etching defects can be avoided. Furthermore, by performing organic substance removal with a solution containing ozone, it becomes possible to remove organic substances more effectively than when ozone gas alone is used. Furthermore, by performing the treatment in a sealed atmosphere, it is possible to minimize air pollution caused by harmful ozone gas that volatilizes during the treatment.
[0016]
In addition, by removing the organic substance and the Sn layer after forming the transparent electrode, it is possible to remove only the Sn layer where the substrate surface other than the transparent electrode pattern is exposed, thereby effectively preventing yellowing. It becomes.
[0017]
Furthermore, when the solution containing ozone contains at least one of acetic acid, propionic acid, butyric acid, dichloromethane, and pure water, the larger the amount of ozone dissolved in the solution containing ozone, the greater the effect of removing organic substances. As a solution capable of effectively dissolving ozone, a preferable solution from the viewpoint of influence on the environment, hygiene, etc., is represented by the formula: C _n H _{2n + 1} (COOH) [n = 1, 2 or an integer of 3]. Fatty acids (acetic acid, propionic acid, butyric acid) and dichloromethane, and when one of these is used, ozone can be effectively dissolved in the solution. A solution in which ozone is dissolved in pure water generally used as ozone water can also be used, although the effect is reduced.
[0018]
Further, the invention according to claim 3, after manufacturing the front plate of the plasma display device, after forming the transparent electrode, after removing the organic matter adhered on the substrate using a solution containing at least ethylene carbonate, It is characterized by performing a cleaning / etching process to etch the substrate surface, and then forming a bus electrode. By removing organic matter with a solution containing ethylene carbonate, it is more effective than when only ozone gas or a solution containing ozone is used. Thus, organic substances can be removed. In addition, since ethylene carbonate is odorless and has low toxicity, it is friendly to the environment and management of exhaust and waste liquid becomes easy.
[0019]
Furthermore, by removing the organic substance and Sn layer after forming the transparent electrode , it is possible to remove only the Sn layer where the substrate surface other than the transparent electrode pattern is exposed, and effectively prevent yellowing. It becomes. Furthermore, by performing organic substance removal with a solution containing ethylene carbonate, it becomes possible to remove organic substances more effectively than when ozone gas alone or a solution containing ozone is used. In addition, since ethylene carbonate is odorless and has low toxicity, it is friendly to the environment and management of exhaust and waste liquid becomes easy.
[0020]
By the above method, the organic substance adhering to the surface of the plasma display substrate and the Sn layer on the substrate surface can be effectively removed, thereby providing a high-quality plasma display device free from yellowing.
[0021]
Hereinafter, a method of manufacturing a plasma display device according to an embodiment of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is a process flow schematic diagram in a method for manufacturing a front plate of a plasma display device according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing a state of a main process in the manufacturing method.
[0023]
First, a high strain point glass substrate for plasma display generated by the float process is prepared and received (substrate reception). This high strain point glass substrate can be obtained by pouring a high strain point glass material onto a molten Sn bath, stretching it into a flat plate shape, and cleaving it into a desired size. In addition, when it is molded on the Sn bath, not only the surface in contact with the Sn bath and the glass but also the opposite surface is diffused by high temperature Sn, as shown in FIG. Sn layers 15 and 16 are formed on the surface of the substrate 1. The Sn layers 15 and 16 are approximately 5 μm on the surface not in contact with the Sn bath. In order to improve the smoothness of the substrate surface, it may be lightly polished after being cleaved.
[0024]
Next, after cleaning the front substrate 1 through a normal cleaning process, as shown in FIG. 2B, an ITO film is formed on the substrate by ion sputtering or the like, and a resist is formed on the ITO film. After patterning into a shape, an ITO pattern is formed by etching, and the resist is removed to form the transparent electrode 3 (transparent electrode formation). As the transparent electrode material can be used SnO ₂ and the like. At this time, since the transparent electrode 3 is formed without removing the Sn layer 15 on the surface, the Sn layer 15 exists immediately below the substrate surface of the transparent electrode 3. Then, after forming the transparent electrode 3, as shown in FIG. 2 (C), the front substrate 1 is subjected to an organic substance removal treatment with an ozone acetic acid solution, and the Sn layer 15 on the surface of the front substrate 1 is removed by etching. By performing etching after removing the organic matter in this way, the Sn layer 15 can be removed effectively.
[0025]
The cleaning / etching process will be described in more detail. First, the ozone acetic acid solution is adjusted to an ozone concentration of 200 ppm by dissolving ozone gas generated by discharge in acetic acid by bubbling. Next, the substrate is washed with water, and then the ozone acetic acid solution is moved to an organic matter treatment tank that ejects by shower, and an organic matter removal treatment is performed (organic matter removal treatment). At this time, the shower is swung so that the ozone acetic acid solution uniformly hits the front surface of the substrate. In addition, in order to make the organic matter treatment tank a sealed atmosphere, a mechanism is provided to close the shutter when the substrate passes before and after the organic matter treatment tank so that ozone gas generated during the treatment does not leak into the atmosphere. In addition, the processing time exposed to ozone acetic acid is about 1 minute.
[0026]
Here, the solution for dissolving ozone is not limited to acetic acid, and at least one selected from acetic acid, propionic acid, butyric acid, dichloromethane, and pure water is used. Moreover, the processing time should just be time for organic substance removal, and processing time is not restricted to 1 minute.
[0027]
Next, after passing through the organic matter treatment tank, a water washing treatment is performed, and the wafer is moved to the etching treatment tank to perform the etching treatment. The etching tank is a dip type, and is immersed in an etching tank filled with hydrofluoric acid for about 2 minutes. In general, since the surface Sn layer is about 5 μm, it is desirable to remove 5 μm or more. However, if the surface Sn layer can be removed without a certain amount without removing the entire surface Sn layer, the degree of yellowing is reduced. It is not limited to 5 μm. Further, the etching solution may not be hydrofluoric acid, and the processing time is not limited to 2 minutes as long as a certain amount of the surface Sn layer 15 can be removed. Next, the substrate that has passed through the etching treatment tank is washed with water, and then dried with an air knife or the like using dust-controlled dry air, thereby completing the cleaning / etching step.
[0028]
At this time, the organic substance is removed over the entire surface of the front substrate 1, but the etching selectively removes only the portion where the surface Sn layer 15 is exposed from the transparent electrode 3. Thereby, deterioration of an etching liquid can be suppressed and a lifetime can be lengthened. In the present embodiment, since the Sn layer 15 remains between the substrate 1 and the transparent electrode 3, there is a possibility that the possibility of yellowing slightly remains on the side surface where the Sn layer 15 at the interface is exposed. Compared with the prior art, the possibility of yellowing can be greatly reduced.
[0029]
Next, a bus electrode is formed (bus electrode formation). In this bus electrode formation process, a photosensitive black paste is used to form a film by a screen printing method or the like, then a photosensitive Ag paste is used to form a film by a screen printing method or the like, and ultraviolet light is emitted through an exposure mask having a desired pattern. After the irradiation, a bus electrode pattern is formed by development processing, and baked at a temperature of about 600 ° C. to remove the resin component in the paste and melt the glass frit, as shown in FIG. The bus electrode 4 is formed. Note that the Ag layer is not limited to one layer, and a plurality of layers may be stacked. Further, if the conductive layer contains Ag as a main component, a formation method using a paste is not necessary.
[0030]
Next, a black stripe is formed (black stripe formation). In this black stripe formation step, a photosensitive black paste is formed by screen printing or the like, then irradiated with ultraviolet light through an exposure mask having a desired pattern, and then a bus electrode pattern is formed by a development process. The black stripe 5 is formed as shown in FIG. 2 (E) by firing at a moderate temperature to remove the resin component in the paste and melting the glass frit. The black stripe may be formed simultaneously with the base black layer of the bus electrode. Moreover, if it is black, it may not be the formation method using a paste. Further, a black stripe may be formed before forming the bus electrode.
[0031]
Next, a dielectric layer is formed (dielectric formation). In this dielectric formation process, a paste mainly composed of PbO—B ₂ O ₃ —SiO ₂ glass or the like is formed into a film by a technique such as a screen printing method or a die coating method, and baked at a temperature of about 600 ° C. Thus, the resin component in the paste is removed and the glass frit is melted to form a dielectric lower layer. Similarly, an upper dielectric layer is formed to form a dielectric layer 6 as shown in FIG. Note that the dielectric layer may not be formed twice. Alternatively, it may be formed by laminating and baking a film-like dielectric precursor molded without using a paste.
[0032]
Next, a dielectric protective layer is formed (dielectric protective layer formation). In this dielectric protective layer forming step, as shown in FIG. 2G, MgO or the like is formed by vacuum deposition or sputtering to form the dielectric protective layer 7.
[0033]
The front plate is completed as described above. Then, the front plate and the back plate are bonded together, and a discharge gas such as Ne—Xe is sealed at a pressure of 53200 Pa (400 Torr) to 79800 Pa (600 Torr) to form a plasma display panel, and then a driving circuit is attached, A display device is completed.
[0034]
The plasma display device manufactured by the above method becomes a high-quality plasma display device free from yellowing which has been a problem in the conventional method by effectively removing organic substances and etching the substrate surface.
[0035]
Here, in the above description, organic substances adhering to the substrate were removed using a solution containing ozone in a sealed atmosphere. However, as this cleaning / etching step, the organic substance adhering to the substrate was used using a solution containing at least ethylene carbonate. The same effect can be obtained even if organic substances are removed.
[0036]
The cleaning / etching process using the solution containing ethylene carbonate will be described in more detail. First, the substrate is washed with water, and then the ethylene carbonate solution is moved to an organic matter treatment tank ejected by a shower to perform an organic matter removal treatment (organic matter removal treatment). ). At this time, the shower is swung so that the ethylene carbonate solution is uniformly applied to the front surface of the substrate, and the temperature of the ethylene carbonate solution is kept at 70 to 80 ° C., and the substrate is moved so as to be exposed to the ethylene carbonate solution for about 1 minute. The speed was adjusted.
[0037]
The liquid temperature is not limited to 70 to 80 ° C. as long as the organic matter can be removed and the temperature is 40 ° C. or higher, and the processing time is not limited to 1 minute as long as the organic matter is removed. Furthermore, the liquid temperature and treatment time are appropriately selected depending on the temperature and time at which the organic matter is removed. Further, not only ethylene carbonate but also ozone may be dissolved in an ethylene carbonate solution by bubbling or the like. Further, ethylene carbonate may be mixed with ozone dissolved in a solution such as acetic acid.
[0038]
That is, in this embodiment, the effect of preventing yellowing can be obtained, and the deterioration of the etching solution in the cleaning / etching process can be suppressed, so that the cost reduction effect in the manufacturing process can be obtained.
[0039]
【The invention's effect】
As described above, according to the present invention, after effectively removing the organic substance, the substrate surface is etched, and the Sn layer on the substrate surface is removed in a state where there is no etching unevenness due to the organic substance. It is possible to provide a high-quality plasma display device that does not change color. Note that the use of odorless and weakly toxic ethylene carbonate makes it easier to manage the exhaust and waste liquid, so that the above-described effects can be obtained with a simpler equipment and method.
[Brief description of the drawings]
FIG. 1 is a process flow schematic diagram in a method for manufacturing a plasma display device according to an embodiment of the present invention . FIGS. 2A to 2G are schematic cross-sectional views showing main processes in the manufacturing method. 3] Schematic cross-sectional view showing the configuration of the plasma display device. [Fig. 4] Perspective view showing the etching failure without removing the organic matter.
DESCRIPTION OF SYMBOLS 1 Front substrate 2 Back substrate 3 Transparent electrode 4 Bus electrode 5 Black stripe 6 Dielectric layer 7 Dielectric protective layer 8 Address electrode 9 Base dielectric layer 10 Partition 11 Phosphor layer 12 Discharge gas 13, 14 Foreign material 15, 16 Sn layer

Claims (3)

Cleaning and etching process for etching the substrate surface after forming transparent electrodes and removing organic substances adhering to the substrate using a solution containing ozone in a sealed atmosphere when manufacturing the front plate of the plasma display device And then forming a bus electrode . A method of manufacturing a plasma display device. The method for manufacturing a plasma display device according to claim 1, wherein the solution containing ozone contains at least one of acetic acid, propionic acid, butyric acid, dichloromethane, and pure water . When manufacturing the front plate of the plasma display device, after forming the transparent electrode, the organic substance adhering to the substrate is removed using a solution containing at least ethylene carbonate, and then the cleaning / etching process is performed to etch the substrate surface. Then, a bus electrode is formed, and a method for manufacturing a plasma display device.

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