JPH10214562A - Manufacture of shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a quality and avoid waste of material by spraying high- pressure water by water jet to the region of through holes formed by dissolving and removing a metallic shadow mask material exposed from a photoresist film before a film peeling-off process so as to remove an etching resistant layer, changing an etching condition based on inspection of a pore diameter, followed by control. SOLUTION: A metallic shadow mask material 1 formed into an elongated band is provided with a plurality of through holes which are formed inside a second etching chamber 10 by etching after formation of an etching preventing layer. Before a film peeling-off process, high-pressure water is sprayed from high-pressure spray nozzles 11, thereby removing the etching preventing layer and a hood-like photoresist film covering the region of the through holes. Thereafter, the shadow mask material 1 is dried by a dryer 14, followed by inspection by an automatic inspector 6 with light irradiation. The passing light is converted into an electric signal, which is then input into an etching condition changing device 13 via a judging device 9. In the case of spray etching, a pore diameter is controlled by changing a spray pressure and/or a temperature of an etchant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shadow mask in which a plurality of openings penetrating a metal material are formed by a photoetching method, and in particular, the diameter of the through holes is small and the number of through holes is small. The present invention relates to a method of manufacturing a high-definition shadow mask.

[0002]

2. Description of the Related Art Conventionally, a shadow mask used for a color picture tube or the like is manufactured by a process using a photo-etching method in which an etching-resistant layer is formed and then etched as shown in the example of FIG. Things. That is, for example, a low carbon steel sheet having a thickness of 0.13 mm is used as a shadow mask metal material (shadow mask material 1), and both sides are degreased, leveled, and cleaned, and then both sides are treated with casein or polyvinyl alcohol and ammonium bichromate. A photoresist film 2 is formed by applying and drying a water-soluble photosensitive solution consisting of Next, one side of the shadow mask material 1 is exposed to the negative pattern of the small hole image and the other side is exposed to the negative pattern of the large hole image via an exposure mask having a predetermined pattern. After that, if a developing process is performed with hot water to dissolve the photoresist film at the unexposed and uncured portions, as shown in FIG. 5A, the small-hole photoresist film 2a exposing the shadow mask material 1 from the opening is formed. And a large-hole photoresist film 2b on the front and back.

After a hardening process and a burning process are performed on the photoresist film 2, a first stage etching is performed from both front and back surfaces. Generally, the etching is performed by spray etching using a ferric chloride solution. In the first etching step, as shown in FIG. 5B, it is important to stop the etching progress halfway.

Next, after the shadow mask material 1 is washed with water, washed and dried, for example, a photocurable resin is applied by a gravure coating method or the like, and the resin is irradiated with light to obtain a light-shielding resin as shown in FIG.
As shown in (c), an etching prevention layer 4 is formed to completely fill the small hole side recess 3a formed by the preceding etching. The surface on which the etching prevention layer 4 is formed may be on the small hole side or on the large hole side, but is often formed on the small hole side.

Subsequently, as shown in FIG. 5D, a second etching step of etching the shadow mask material 1 only from the large hole side is performed, and the concave portion 3b on the large hole side is enlarged. Then, a through hole 5 penetrating through the small hole is formed. Finally, a stripping step of stripping and removing the etching prevention layer 4 and the photoresist film 2 is performed to obtain FIG. 5E, and then unnecessary portions are cut to obtain a flat type shadow mask.

A large number of small-diameter through-holes 5 are formed in a predetermined arrangement on the shadow mask obtained by the above-described manufacturing method and the like. When incorporated, it serves to guide the electron beam correctly to the phosphor screen. Therefore, the shape of each through-hole 5 to be formed on the shadow mask, particularly the diameter of the through-hole,
The hole diameter is set in advance in a design stage before manufacturing the shadow mask, and the hole diameter is set so that the color picture tube or the like can exhibit desired performance when the shadow mask is incorporated into the color picture tube or the like.

However, in many cases, the diameter of the through hole 5 is not as desired for the following reasons. For example, in the etching process, the etching conditions, that is, the setting of the liquid temperature of the etching solution, the spray pressure and the like fluctuate, and the etching conditions are suitable conditions due to changes in the concentration of the etching solution, fluctuations in the etching solution such as fatigue, and the like. From
This is because the size of each formed recess is not as desired, and as a result, the through hole formed by the recess has a poor hole diameter.

For this reason, in the production of the shadow mask, after forming the through-hole 5, an inspection of the diameter of the through-hole 5 (hereinafter, simply referred to as "inspection of the through-hole") is performed.
As a result of the inspection, when a hole diameter defect of the through hole 5 is found, a shadow mask having a desired hole diameter is obtained by changing manufacturing conditions, for example, etching conditions to suitable conditions, in order to obtain a desired through hole 5. It is a thing.

As a means for inspecting the through-hole, there is a method of enlarging five portions of the through-hole using a loupe, a microscope, or the like, and inspecting the hole diameter with the naked eye. However, recently, the number of cases where the inspection is performed by the automatic inspection machine 6 has been increasing for the purpose of improving the efficiency of the inspection and improving the inspection accuracy.

The principle of the automatic inspection machine 6 will be briefly described below. That is, as shown in the example of FIG. 6, light from a light source 7 such as a high-frequency fluorescent lamp is applied to an inspection site of the shadow mask material 1, and light passing through the through hole 5 formed in the shadow mask material 1 is The light is received as an optical image by, for example, a solid-state imaging camera 8 or the like provided on the side opposite to the light source 7 with the shadow mask material 1 interposed therebetween. This light image is then converted to an electrical signal,
The electric signal is received by a judging means 9 composed of, for example, a computer, and the judging means 9 inspects and judges whether or not the through hole 5 has a desired hole diameter.

In the conventional method of manufacturing a shadow mask, if there is an etching resistant layer such as the photoresist film 2 and the etching preventing layer 4, the etching resistant layer hinders the inspection of the through hole. After performing a film removing step of removing the etching resistant layers such as the photoresist film 2 and the etching prevention layer 4 formed on the material 1,
Inspection of the through hole is performed using the above-described automatic inspection machine or the like.

That is, when the shadow mask material 1 having the photoresist film 2 in which the shadow mask material 1 is exposed from the opening is etched, the shadow mask material 1 is etched isotropically from the opening. is there. Therefore, as shown in FIG. 4, the photoresist film 2 forms an overhang-shaped eave 12 in the concave portion formed in the shadow mask material 1. The eaves 12 block the inspection of the hole diameter in order to block the irradiation light emitted at the time of inspection of the through-hole and to obscure the contour shape of the through-hole 5.

Further, even when the etching prevention layer 4 is formed, the etching prevention layer 4 scatters or blocks the irradiation light to obscure the contour shape of the through-hole 5, thereby enabling accurate inspection. I can't say that.

For this reason, in the conventional method of manufacturing a shadow mask, the through-hole is not formed in the shadow mask after the film removing step, that is, after removing the etching resistant layers such as the photoresist film 2 and the etching prevention layer 4 from the film. Inspection was underway. Depending on the method of manufacturing the shadow mask, after the etching step is completed, a test piece is cut out of the shadow mask material 1, and the etching-resistant layer on the surface of the test piece is scraped off with a brush or the like. After that, there is a method of changing manufacturing conditions according to the inspection.

[0015]

Normally, the shadow mask material 1 is in the form of a long strip supplied from a take-up roll, and the shadow mask is manufactured continuously. As described above, in the conventional method for manufacturing a shadow mask,
The through-hole was inspected after the film removing step, or the through-hole was inspected using a test piece cut from the shadow mask material 1. For this reason, it takes time from the completion of the etching process to the completion of the film removing process, or even in the case of the sampling inspection, it takes time to cut out the test piece and scrape the etching resistant layer. For this reason, even if a hole diameter defect occurs due to a manufacturing process that deviates from suitable conditions, for example, an etching process, it takes time to find the defect, and also, until the defect is eliminated by changing the manufacturing conditions. Has taken even longer. As described above, since the shadow masks are manufactured continuously, there is a problem that a large number of shadow masks having a defective hole diameter are manufactured before the inspection and the manufacturing conditions are changed.

By the way, a shadow mask having a defective hole diameter is difficult to use and is often discarded, resulting in wasted material. In addition, since the production of the shadow mask is performed again, the production line may be confused and the production efficiency may be reduced.

Further, in order to expedite the discovery of a defective hole diameter as much as possible, the following problems occur even in the above-described sampling inspection after the end of the etching step. That is, since a portion cut out from the shadow mask material 1 becomes weak in strength, if tension such as conveyance is applied to the shadow mask material 1, a cut occurs at the cut portion, and the cut end is conveyed by a conveyance roller or the like. This causes problems such as winding around the means. Further, when the shadow mask material 1 is wound around the transporting roller, an extra external force is applied to the shadow mask material 1, so that wrinkles and the like are generated on the shadow mask, which may be considered to be defective.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a high-quality shadow mask can be obtained by inspecting a through-hole with high accuracy at an early stage. It is intended to provide a method for manufacturing a mask.

[0019]

In order to achieve the above object, according to the present invention, there is provided a method for forming an etching resistant layer comprising at least a photoresist film on a surface of a shadow mask metal material. Forming a plurality of through holes by dissolving and removing a portion of the shadow mask metal material exposed from the photoresist film, and removing the etching resistant layer; Means for removing the etching-resistant layer at the through-hole portion by spraying high-pressure water using a water jet to the shadow mask metal material after the film is formed and before the film removing step, and the hole diameter of the through-hole is desired. Means for inspecting whether or not the etching is performed, and etching the shadow mask metal material in the etching step based on the inspection result. And means for changing the conditions, in which the method of manufacturing a shadow mask for a through hole and to control the desired pore size.

According to a second aspect of the present invention, the means for etching the shadow mask metal material is spray etching, and the etching conditions are changed by changing at least one of the spray pressure and the temperature of the etchant. The method of manufacturing a shadow mask according to claim 1.

Further, in the present invention, the inspection as to whether or not the diameter of the through-hole is desired is performed by irradiating light to the metal surface of the shadow mask and using the light passing through the through-hole. A shadow mask manufacturing method according to claim 1 or 2.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to explanatory views schematically showing an embodiment of the present invention. The embodiments of the present invention are not limited to the following drawings and descriptions, and it goes without saying that various modifications may be made based on the spirit of the present invention.

In FIG. 1, a shadow mask material 1 is supplied from a take-up roll and is conveyed from left to right on the sheet by means of conveying rollers or the like (not shown). 0.13mm amber material). The steps up to the formation of the etching prevention layer 4 have been completed according to the steps and the like described in the above section (prior art). Here, the shadow mask material 1 is subjected to spray etching using a ferric chloride solution as an etchant in the second etching chamber 10 so that, as shown in FIG. A penetrating through hole 5 is formed.

In the conventional method of manufacturing a shadow mask, the shadow mask material 1 that has exited the second etching chamber 10 is subjected to a film removing step. However, in the present invention, prior to the film removing step, as shown in FIG. 1, a high pressure water is sprayed from a high pressure spray nozzle 11 to apply a high pressure to the shadow mask material 1 which has exited the second etching chamber 10. It sprays water.

Next, the conveyed shadow mask material 1
Is dried by a drying device 14 composed of a far-infrared heater or the like, and then the through hole is inspected by the automatic inspection machine 6 described above. The arrangement of the high-pressure spray nozzles 11 is such that high-pressure water is sprayed onto the shadow mask material 1 region where the through-holes 5 are formed, and the photoresist film 2 and the etching prevention layer 4 in each through-hole 5 region can be removed. For example, a plurality of high-pressure spray nozzles 11 are arranged in a direction perpendicular to the conveying direction of the shadow mask material 1. Further, in this embodiment, in order to completely remove the photoresist film 2 and the etching prevention layer 4, a plurality of spray nozzles 11 provided in a direction perpendicular to the conveying direction of the shadow mask material 1 are provided on both sides of the shadow mask material 1. Are arranged.

That is, as shown in FIG. 4, the through hole 5 of the shadow mask material 1 after the second etching is covered with the etching preventing layer 4, and the resist film 2 at the through hole 5 is An overhang-shaped eave 12 is formed by side etching at the time of etching. Here, by spraying high-pressure water onto the shadow mask material 1 with a water jet, as shown in FIG. 3, the etching prevention layer 4 covering the region of the through-hole 5 and the eave-shaped photoresist film 2 are formed. It is blown off and the through hole 5 is exposed from the etching resistant layer. The inventors have empirically obtained that the pressure of the high-pressure water at this time is preferably about 100 to 300 Kgf / cm ² . However, depending on the manufacturing conditions such as the material and thickness of the resist film 2 and the etching prevention layer 4, the diameter of the through hole 5, and the distance from the high-pressure spray nozzle 11 to the shadow mask material 1, the above-described etching prevention layer 4 and the resist film Since the pressure of the high-pressure water required for removing 2 changes, it can be said that it is desirable to appropriately set the pressure of the high-pressure water for each manufacturing condition.

Thus, when inspecting the through-hole, even if the shadow mask material 1 is irradiated with the inspection light, the irradiation light is irradiated onto the through-hole 5 without being hindered. In other words, the outline shape of the through hole is not obscured or the outline shape of the through hole is not obscured by the etching-resistant layer, and the inspection of the through hole described in the section (prior art) can be performed. Become.

That is, as shown in FIGS. 1 and 2,
Light is irradiated from a light source 7 such as, for example, a high-frequency fluorescent lamp to the inspection site where the photoresist film 2 serving as the etching prevention layer 4 and the eaves 12 is removed with high-pressure water, and the shadow mask material 1 is irradiated.
The light passing through the through-hole 5 is received as an optical image by, for example, a solid-state imaging camera 8 provided on the side opposite to the light source 7 with the shadow mask material 1 therebetween. Next, after converting this light image into an electric signal, the electric signal is received by a judgment means 9 such as a computer, etc., and the judgment means 9 inspects and determines whether the through hole 5 has a desired hole diameter, and determines the measured hole diameter. If there is a difference from the desired hole diameter, the difference value is calculated. By using the automatic inspection machine 6, the inspection of the through-hole can be performed accurately and efficiently.

Next, in the shadow mask manufacturing method of the present invention, when a defect in the hole diameter of the through hole 5 is found by the inspection, that is, the difference between the measured hole diameter and the desired hole diameter is set to a predetermined allowable value. If the number exceeds the threshold, the etching condition changing means 13 including a computer or the like
A difference value between the more desired hole diameter and the actually measured hole diameter is received, and based on the difference value, the hole diameter of the through-hole 5 becomes the desired diameter.
This is for changing the etching conditions. The etching conditions (changes in spray pressure and liquid temperature) described below are changed by the etching condition changing means 13 by a pump (not shown) for supplying an etching liquid to the second etching chamber 10, This is performed by controlling a liquid temperature adjusting means (not shown) such as a heater for adjusting the temperature of the liquid.

Further, the shadow mask material 1 after the inspection is transported after the film removing step (not shown) as usual, and after stripping off the remaining etching resistant layer, unnecessary portions are cut off to form a shadow mask material. Is what you do.

As a change in the manufacturing conditions for changing the hole diameter of the through hole 5, the transfer speed of the shadow mask material 1 is changed.
Alternatively, it is conceivable to change the concentration of the etching solution. However, shadow masks are manufactured continuously through each manufacturing process using long strip-shaped materials.
Changing the transport speed is undesirable because it affects other manufacturing processes. Also, changing the concentration of the etchant is complicated and not desirable. For this reason, as described below, it is easy and desirable to change at least one of the spray pressure or the liquid temperature of the etching solution without changing the transport speed of the shadow mask material 1 in order to change the hole diameter. It can be said that.

The following is an example of changing the etching conditions.
The present inventors, when performing the spray etching in the second etching, increase the spray pressure of the etching solution by 1 kgf / cm ² , the hole diameter of the through-hole 5 increases by 1 μm, and raise the solution temperature of the etching solution by 1 ° C. When raised, the hole diameter of the through hole 5 becomes 3μ.
It is empirical that when the spray pressure is reduced by 1 Kgf / cm ² , the hole diameter of the through-hole 5 is reduced by 1 μm, and when the liquid temperature is lowered by 1 ° C., the hole diameter of the through-hole 5 is reduced by 3 μm. Is what I had gained.

Therefore, based on the above-mentioned empirically obtained fluctuation values, the present inventors conducted etching conditions (spray pressure and liquid temperature) based on the difference between the desired hole diameter and the actually measured hole diameter. Is changed as shown in the following example of (Table 1). In Table 1, the numerical value in the column of (pore size) indicates the difference between the measured and measured pore size and the desired pore size, and + (plus) indicates that the measured pore size is larger than the desired pore size. , And-(minus) indicates that the measured pore size is smaller than the desired pore size.

[0034]

[Table 1]

As shown in Table 1, when the difference between the desired hole diameter and the measured hole diameter is small, the spray pressure is changed. When the difference is large, both the spray pressure and the liquid temperature are changed. At the same time. For example, when the difference between the measured hole diameter and the desired hole diameter is minus 1, the spray pressure is increased by 1 kgf / cm ² from the measured spray pressure value when the through hole was formed, and the liquid temperature is kept as it is. By changing the etching conditions, the hole diameter of the newly formed through hole is increased by 1 μm from the hole diameter before the condition change. When the difference is minus 4, the spray pressure is set to 1 from the measured spray pressure when the through hole is formed.
In addition to increasing Kgf / cm ² , the liquid temperature is raised by 1 ° C. from the measured temperature of the etching solution at the time of forming the through hole, and the hole diameter of the newly formed through hole is increased by 4 μm.
Similarly, in accordance with the difference between the measured hole diameter and the desired hole diameter, the change values of the spray pressure and the liquid temperature are appropriately set, and the spray pressure and the liquid temperature are simultaneously changed as necessary. When the measured pore diameter is a desired pore diameter, the spray pressure and the liquid temperature are not changed and are left as they are.

The through hole 5 newly formed under the changed etching conditions is inspected again by the above-mentioned method using the water jet, and if the hole diameter is different from the desired one, the etching conditions are further changed. This is repeated until the desired pore size is reached. Thereby, it becomes possible to make the hole diameter of the through hole a desired diameter.

The inventors of the present invention set the allowable range of the spray pressure at the time of the second etching to 1 to 7 kgf / cm ² and the allowable range of the liquid temperature to 60 to 80 ° C. The conditions have been changed. For some reason, if the spray pressure and the liquid temperature are excessively changed to exceed the allowable range, the etching shape will be insufficient, the etching will be excessive and the etching shape will be changed, and the adverse effects such as damaging the etching resistant layer will be adversely affected. This is to get out. In addition,
Since the allowable range varies depending on the manufacturing conditions of the shadow mask, it is desirable to appropriately set the allowable range according to the manufacturing conditions of the shadow mask.

[0038]

According to the conventional method for manufacturing a shadow mask,
Poor hole diameter of the through-hole could not be found unless inspection was performed by sampling after the film removing step or after the etching step. For this reason, even if a defect of the hole diameter is found in the inspection, many shadow masks having the defect have already been etched at that point, and the material has been lost. Also, in the case of sampling inspection after etching, there is a problem that an accident such as cutting of a shadow mask material is likely to occur.

However, according to the method of manufacturing a shadow mask of the present invention, the inspection of the through-hole can be performed immediately after the end of the etching step, and even if a defect is found, the manufacturing conditions, particularly the etching conditions, are changed promptly. Can be performed. For this reason, it is possible to minimize the production of a shadow mask having a defective hole diameter, to prevent the loss of materials as in the related art, and to maintain favorable etching conditions. Can be

Further, in the conventional sampling inspection, since the inspection site is partially cut out from the shadow mask material, even if there is no defect as a result of the inspection, the shadow mask from which the inspection site has been cut has to be discarded instead of becoming usable. Not
Further, the problem of cutting the shadow mask material described above has also occurred. However, according to the present invention, when there is no defect as a result of the inspection, the shadow mask can be flowed directly to the film removing step, so that the loss of material can be prevented, and the problem of cutting the shadow mask material does not occur. etc,
It can be said that the present invention is practically excellent in obtaining a high quality shadow mask.

[0041]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part of one embodiment of a method of manufacturing a shadow mask of the present invention.

FIG. 2 is an explanatory view showing a main part of an example of hole diameter measurement in the shadow mask manufacturing method of the present invention.

FIG. 3 is an explanatory view showing an example of removing an etching resistant layer in the method of manufacturing a shadow mask according to the present invention.

FIG. 4 is an explanatory view showing a main part of an example of hole diameter measurement in a conventional shadow mask manufacturing method.

5A to 5E are explanatory views showing an example of a method of manufacturing a shadow mask in the order of steps.

FIG. 6 is an explanatory diagram showing a configuration example of an automatic inspection machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shadow mask material 2 Photoresist film 3 Concave part 4 Etch prevention layer 5 Through hole 6 Automatic inspection machine 7 Light source 8 Solid-state imaging camera 9 Judgment means 10 Etching chamber 11 High pressure spray nozzle 12 Eave 13 Etching condition changing means 14 Drying device

Claims (3)

[Claims] A step of forming an etching-resistant layer made of at least a photoresist film on the surface of a shadow mask metal material; and etching to form a plurality of through holes by dissolving and removing portions of the shadow mask metal material exposed from the photoresist film. In a method of manufacturing a shadow mask having at least a step of removing a film of the etching-resistant layer, after the through-holes are formed, and before the removal of the film, the shadow mask metal material is sprayed with high-pressure water using a water jet. Do
Means for removing the etching-resistant layer at the through-hole site,
Means for inspecting whether the hole diameter of the through hole is a desired one, and means for changing etching conditions for the shadow mask metal material in the etching step based on the inspection result; A shadow mask having a desired diameter. 2. The method according to claim 1, wherein the means for etching the shadow mask metal material is spray etching, and the etching conditions are changed by changing at least one of the spray pressure and the temperature of the etchant. The manufacturing method of the shadow mask of the description. 3. The method according to claim 1, wherein the inspection of whether or not the diameter of the through-hole is desired is performed by irradiating the shadow mask metal material with light and passing through the through-hole. 3. The method for manufacturing a shadow mask according to item 2.