JPH08300262A - Thick-film pattern formation - Google Patents

Abstract

PURPOSE: To reconcile the grinding easiness of a pattern forming material and the surface smoothness of a finished pattern at the time of forming a thick-film pattern by a subtractive process. CONSTITUTION: After a pattern forming material corresponding to an opening part of a resist 7 is removed by a subtractive process, a resin binder in the rest of the pattern forming material 4 is swollen by a solvent, or a polymer solution or polymer dispersant liquid is impregnated in the pattern forming material 4 and then a separation process of the resist 7 is made so as to be carried out. Since an extent of sticking force of inorganic fine particles themselves in the pattern forming material 4 is increased, while in order to facilitate grinding work in the subtractive process, flexibility is imparted to the resign binder, being so far no flexibility, in the separation process of the resist 7, such a possibility that a surface part of the pattern forming material 4 might be taken away by the resist and/or any damage be given to the pattern forming material 4 will never happen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thick film pattern in a manufacturing process of a liquid crystal display device, a fluorescent display device, a plasma display panel, a hybrid integrated circuit and the like, and more particularly to a barrier forming method for a plasma display panel. The present invention relates to a thick film pattern forming method used.

[0002]

2. Description of the Related Art Generally, a plasma display panel, which is a gas discharge panel, is provided with a large number of cells as minute discharge spaces sandwiched between two substrates, and each cell discharges and emits light or is generated. The phosphor is made to emit light by the ultraviolet rays. Barriers are provided between these minute cells in order to prevent mutual interference between the cells and to keep the distance between both substrates constant. Then, in the usual case, this barrier is formed by patterning by screen printing on one substrate using a barrier forming paste.

By the way, in the above plasma display panel, in order to make the discharge space as large as possible and to obtain high-intensity light emission, a wall is cut vertically and a barrier having a narrow width and a high height is required. Particularly in a high-definition display, for example, a height of 100 μm and a width of 30 to 50 μm
Such a high aspect ratio barrier is required. However, in the above-mentioned screen printing, since the film thickness that can be formed by one printing is several tens of μm at most, it is necessary to repeat printing and drying a large number of times, generally 10 times or more, resulting in poor productivity. There is a point. In addition, since the coating film formed by screen printing has a dented peripheral portion and a convex shape, when overprinting a large number of times, there is the problem that sagging accumulates and the bottom portion expands. There was a limit. Further, in screen printing, there is a problem in that the pitch accuracy is limited due to the distortion of the printing plate, and it is not possible to cope with an increase in the size of the panel.

As a method capable of solving such a problem,
A barrier formation method using a subtractive method has been proposed (Electronic Materials, 1983, No. 11, p13).
8). That is, after forming the barrier forming layer, a subtractive resist mask is formed on the upper surface by printing or photolithography, and the barrier forming material in the opening of the resist mask is removed. Among them, what is called a sandblasting method, in which fine particles mixed with a compressed gas are jetted at high speed to physically perform etching, is particularly expected. By using this sandblasting method, it is possible to process the barrier material into a desired shape in which the wall surface is cut vertically and the width is narrow and the height is high. Further, by adopting a photolithography process for patterning the resist, it is possible to increase the pattern accuracy, so that it is possible to cope with an increase in size.

[0005]

Although the sandblasting method has the above advantages, it requires a large amount of energy and powder (grinding material) for grinding, and the time required for grinding is long, resulting in high cost. There is a problem. In addition, there is a problem that constituent materials such as the electrodes of the barrier pattern, the electrodes exposed in the peripheral portion of the panel, the dielectric layer, and the glass substrate are damaged by sandblasting. Therefore, the barrier forming layer to be ground is required to be ground as easily as possible.

Generally, the barrier-forming material mainly contains ceramic powder such as alumina or zirconia that does not soften during the firing process and low-melting glass powder that flows and adheres during the firing process. Further, in order to form a coating film of these powders before firing, a glass paste containing a small amount of a resin that can be burned off by being vaporized, burned, decomposed or the like is used. In order for the barrier-forming material having such a structure to be easily ground, it is preferable that the powder is filled as loosely as possible, the porosity is high, and the adhesion force between the powders is weak. In order to achieve this, the following measures are specifically taken. (1) Minimize the amount of resin used. (2) A large powder is used, or powders having a high non-sphericality and a low filling rate are mixed and used. (3) Use a brittle resin having low flexibility.

However, the barrier-forming material which is easily ground by these methods has low mechanical strength, and particularly when water or an alkaline aqueous solution permeates, the barrier-forming material is extremely reduced in strength. When the resist is generated or is taken off, the barrier material of the surface portion is brought to the surface, which causes a problem that the smoothness of the surface is deteriorated. Therefore, there is a limit to improving the ease of grinding the barrier material. It should be noted that this is not limited to the barrier formation of the plasma display panel described above, and generally causes a similar problem when a thick film pattern is formed by a subtractive method.

The present invention has been made in view of the above circumstances, and an object thereof is to facilitate the grinding of the pattern forming material and the finish pattern when forming the thick film pattern by the subtractive method. It is to provide a method for forming a thick film pattern having both surface smoothness.

[0009]

In order to achieve the above object, a first method according to the present invention provides a pattern forming layer made of a pattern forming material containing an inorganic powder and a resin binder as main components on an object. , A step of forming a resist pattern on the pattern forming layer, a step of removing the pattern forming material corresponding to the resist opening, a step of peeling the resist, and a step of sintering the pattern forming material by firing. In the thick film pattern forming method including the step of performing, a step of swelling the resin binder in the pattern forming material with a solvent is performed before the step of removing the resist.

In order to achieve the same object, the second method according to the present invention is to form a pattern forming layer made of a pattern forming material containing an inorganic powder and a resin binder as main components on an object. A step, a step of forming a resist pattern on the pattern forming layer, a step of removing the pattern forming material corresponding to the resist opening, a step of peeling the resist, and a step of sintering the pattern forming material by firing. In the method of forming a thick film pattern including, the step of impregnating the pattern forming material with the polymer solution or the polymer dispersion is performed before the step of removing the resist.

The present invention will be described in detail below by taking the formation of a barrier of a plasma display panel as an example.
It should be noted that the present invention can be widely applied when forming a thick film pattern by a so-called subtractive method, and is particularly effective when patterning by a sandblast method. The "thick film" referred to in the present invention is a film obtained by dispersing an inorganic powder such as metal, ceramic, or glass in a vehicle, applying this, and then fixing the same, which has a large thickness. Does not mean. By the way, the present invention can be applied to pattern formation with a film thickness of about 2 μm.

The resin binder used in the barrier forming material which is a pattern forming material must be burned / decomposed / vaporized at a low temperature so that carbides do not remain in the barrier. -Α-Methylstyrene, polyvinyl alcohol and the like are preferably used.

The barrier forming layer is formed by using a coating liquid which has been made into an ink with a volatile solvent, applying the coating liquid on a substrate, and then heating and drying. As the coating method of the barrier forming layer, screen printing, blade coating,
Comma coating, reverse roll coating, spray coating, gun coating, extrusion coating, lip coating and the like are preferably used. The ink used here is a paste-like coating liquid kneaded by a roll mill using a low-volatile solvent as used in screen printing, or a slurry-like coating liquid kneaded by a ball mill or the like. Both can be used.

The coating is generally performed on a glass substrate, but in some cases, it is also possible to coat on a film and transfer it to the glass substrate. It is also possible to form a barrier forming layer and a resist layer on the film side and transfer them simultaneously to the glass substrate.

In the first method, as described above, the resin binder is swollen with the solvent before the resist is peeled off. The term "solvent" as used herein refers to a wide range of organic compounds that are liquid at room temperature, and generally includes those used as surfactants and plasticizers. As a method of swelling the resin binder with this solvent, a method of immersing in a solvent, a method of spraying a mist of the solvent, a method of exposing to the vapor of the solvent, and the like are used. By swelling the resin binder with the solvent in this manner, the volume of the resin binder is increased, and the adhesive force between the powder particles is increased. In addition, flexibility is imparted to the resin binder whose flexibility has been eliminated in order to facilitate grindability in sandblasting, and strength that opposes the pressure of the spray and the pressure of the air gun is created.

The solvent used when immersed in the solvent is preferably selected so that it does not easily dissolve the resin binder but only swells it. For example, a resin binder generally used has an ethoxyl group content of 4
When it is about 8 to 49.5% of ethyl cellulose, isopropanol, normal propanol, diacetone alcohol, glycol diacetate, methyl cellosolve, carbitol, cyclohexane, terpineol and the like can be used. Further, high boiling point compounds such as glycerin, dibutyl phthalate and dioctyl phthalate can also be used. Also, a mixed solution system can be used. In the method of spraying the mist of the solvent and the method of exposing to the vapor of the solvent, it is possible to use a solvent having higher solubility.

After passing through the swelling step, it is possible to immediately proceed to the resist stripping step, but an appropriate drying step may be performed in order to adjust the amount of solvent contained in the thick film pattern. When the solvent used has a high volatility, drying at room temperature is sufficient, but when a solvent having a low volatility is used, it is preferably dried by heating or reducing the pressure.

In the second method, as described above, the polymer solution or polymer dispersion is impregnated before the resist is stripped. As the method of impregnation, a method of immersing in a polymer solution or a polymer dispersion or a method of spraying a mist of the polymer solution or polymer dispersion is used. By impregnating the pattern forming material with the polymer solution or the polymer dispersion in this manner, the adhesive force between the powders is increased and flexibility is imparted.

The solvent or dispersion medium used here is preferably one that does not readily dissolve the resin binder. Further, the polymer needs to be burned / decomposed / vaporized at a low temperature in the firing process, and examples thereof include a cellulose resin, an acrylic resin, poly-α-methylstyrene, polyvinyl alcohol, and polyethylene oxide. For example,
When the resin binder is ethyl cellulose having an ethoxyl group content of 49.5% or more, a methanol solution or ethanol solution of ethyl cellulose having an ethoxyl group content of 48 to 49.5% can be used. Further, a diacetone alcohol solution of nitrocellulose, an isopropanol / water mixed solution of cellulose acetate propionate, and the like can also be used. Also, an aqueous solution of polyvinyl alcohol,
An aqueous solution of polyethylene oxide, an aqueous solution of hydroxyethyl cellulose, an aqueous solution or dispersion such as an acrylic latex emulsion can also be used.

The resist pattern can be formed by directly patterning by printing, but in the case of performing high-precision processing in a large area, it is preferable to use a photoresist as a resist material and a photolithography method. . As the photoresist, either a dry film resist or a liquid resist can be used, and they can be used in combination. As the resist, there are an alkali developing type, a water developing type and an organic solvent developing type, but an alkali developing type or a water developing type which has a small effect on the environment is preferably used.

The resist is preferably stripped using a stripping solution. A method of spraying a stripping solution from above the panel is preferably carried out to obtain stability in mass production. Further, the baking process after the resist is peeled off is suitably performed in an oxidizing atmosphere at a peak temperature of 500 to 600 ° C.

[0022]

In the thick film pattern forming method of the present invention having the above-mentioned constitution, before the step of peeling the resist, the fixing force between the powders is increased and the resin binder is given flexibility, The peeling liquid resistance and mechanical strength of the pattern forming material are improved, and the resist can be favorably peeled off even if the pattern forming material which is easily ground by the subtractive method is used.

[0023]

EXAMPLES Examples of the present invention will now be described together with comparative examples with reference to the process diagrams shown in FIGS. Here, the case where a barrier is formed on the back plate of the plasma display panel is taken as an example.

Example 1 First, as shown in FIG. 1A, an electrode 2 was formed on a substrate 1 made of glass, a dielectric layer 3 was formed thereon, and then a barrier forming material 4 was formed. A glass paste having the following composition A (% by weight) was applied by a reverse roll coater. Then, after drying with a hot plate at 100 ° C. for 30 minutes, further 15
It was dried at 0 ° C. for 20 minutes to obtain a coating film having an average film thickness of 160 μm.

<Composition A> Glass frit (Nippon Electric Glass, GA-21) 46.7 Grinded brown alumina (Fujimi Abrasives Industry, WA # 8000) 12.0 Black pigment (Nippon Denki Kagaku, heat-resistant black 4200) ) 18.1 Ethyl cellulose (Ethcel std.20 manufactured by Nisshin Kasei) 1.3 Terpineol 10.2 Butyl carbitol acetate 10.2 Triphenyl phosphate 0.5 Di-2-ethylhexyl phthalate 1.0

Then, the substrate 1 is heated to 80 ° C.
As shown in (b), a dry film resist 5 was laminated. The dry film resist 5 used is “NCP225” manufactured by Nippon Synthetic Chemical Industry. Next, FIG.
As shown in (c), line width 80 μm, pitch 220 μm
Exposure was performed with ultraviolet rays through the line pattern mask 6. The exposure condition is an intensity of 220 μW at 364 nm.
/ Cm ² , and the irradiation dose is 120 mJ / cm ² . After exposure,
Spray development was performed with a 1 wt% aqueous solution of sodium carbonate at a liquid temperature of 30 ° C. Through the above steps, a sandblast resist pattern 7 having a line width of 80 μm and a pitch of 220 μm was obtained as shown in FIG.

After forming the resist pattern 7, 50
After drying and aging for 2 hours at ℃, as shown in FIG. 2 (a), unnecessary portions were removed by sandblasting. In this case, the distance between the nozzle and the substrate 1 was set to 10 cm, and the sand blasting treatment was performed using brown fused alumina # 1000 as the abrasive at a jet pressure of 3 kg / cm ² . The time required for grinding on a diagonal 20-inch substrate was 45 minutes.

After finishing the sandblasting process, as shown in FIG.
As shown in (b), the entire substrate 1 was dipped in isopropanol as the solvent 8. Then, after 5 seconds, it was taken out and dried at room temperature for 5 minutes.

Subsequently, as shown in FIG. 2 (c), the resist pattern 7 was stripped using a stripping solution. Specifically, a 2.0 w% aqueous solution of sodium hydroxide was used as a stripping solution, and spray stripping was performed at 30 ° C. Then, after washing with water, it was dried in an oven at 80 ° C. for 15 minutes. Then, it was fired at a peak temperature of 560 ° C. to bind the barrier forming material as shown in FIG. As a result, there is no damage such as chipping, and the barrier 9 has a good surface smoothness.
Was formed. Moreover, the disconnection of the electrode 2 did not occur.

Comparative Example 1 In Example 1, after the sandblasting treatment was completed, the resist pattern 7 was peeled off without immersing it in isopropanol, and then baked at a peak temperature of 560 ° C. to form the barrier-forming material on the substrate. Tie to 1. When the barrier formed in this way was observed with a microscope, many defects of 50 μm or more were found. Further, unevenness of about 5 μm was observed on the entire surface.

(Example 2) In Example 1, the following steps were carried out instead of immersing the substrate 1 after the sandblast treatment in a solvent. That is, a 10 wt% solution of nitrocellulose (1/2 second RS, manufactured by Hercules Co., Ltd.) dissolved in diacetone alcohol was sprayed with a sprayer and sprayed on the substrate 1. And 60
After drying at 15 ° C. for 15 minutes, the barrier forming material was bound through the resist pattern 7 peeling step and the baking step as in the example. Also in this example, there was no damage such as chipping and a good barrier 9 having a high surface smoothness was formed. Moreover, the disconnection of the electrode 2 did not occur.

[0032]

As described above, according to the thick film pattern forming method of the present invention, after removing the pattern forming material corresponding to the resist opening by the subtractive method, the resin binder in the remaining pattern forming material is removed by the solvent. Or the pattern forming material is impregnated with the polymer solution or the polymer dispersion, and then the resist stripping step is performed, thereby increasing the adhesive force between the inorganic powders in the pattern forming material. Since flexibility is imparted to the resin binder whose flexibility has been eliminated to facilitate the subtractive grinding, the surface portion of the pattern forming material is brought to the resist in the resist stripping process, or the pattern formation is performed. A thick film pattern with good surface smoothness can be obtained without damaging the material. It is possible.

[Brief description of drawings]

FIG. 1 is a first half process diagram showing an embodiment of a thick film pattern forming method according to the present invention.

FIG. 2 is a process diagram of the latter half of FIG.

[Explanation of symbols]

 1 substrate 2 electrode 3 dielectric layer 4 barrier forming material (pattern forming material) 5 resist 6 mask 7 resist pattern 8 solvent 9 barrier

Claims (8)

[Claims] 1. A step of forming a pattern forming layer made of a pattern forming material mainly composed of an inorganic powder and a resin binder on an object, a step of forming a resist pattern on the pattern forming layer, and a resist. In a thick film pattern forming method including a step of removing the pattern forming material corresponding to the opening, a step of peeling the resist, and a step of sintering the pattern forming material by firing, before the step of peeling the resist, A method for forming a thick film pattern, which comprises performing a step of swelling a resin binder in a pattern forming material with a solvent. 2. The thick film pattern forming method according to claim 1, wherein the step of removing the pattern forming material corresponding to the resist opening is performed by a sandblast method. 3. The thick film pattern formed is a barrier of a plasma display panel.
Or the thick film pattern forming method described in 2. 4. The method for forming a thick film pattern according to claim 1, wherein the resist material is peelable with an alkaline aqueous solution, and the resin binder in the pattern forming material is water-insoluble. 5. A step of forming a pattern forming layer made of a pattern forming material mainly composed of an inorganic powder and a resin binder on an object, a step of forming a resist pattern on the pattern forming layer, and a resist. In a thick film pattern forming method including a step of removing the pattern forming material corresponding to the opening, a step of peeling the resist, and a step of sintering the pattern forming material by firing, before the step of peeling the resist, A method for forming a thick film pattern, which comprises performing a step of impregnating a pattern forming material with a polymer solution or a polymer dispersion. 6. The method for forming a thick film pattern according to claim 5, wherein the step of removing the pattern forming material corresponding to the resist opening is performed by a sandblast method. 7. The thick film pattern formed is a barrier of a plasma display panel.
Or the thick film pattern forming method described in 6 above. 8. The method for forming a thick film pattern according to claim 5, wherein the resist material is peelable with an alkaline aqueous solution, and the resin binder in the pattern forming material is water-insoluble.