JPH08138539A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE: To provide a shadow mask having a small diameter of aperture by measuring optical density of photosensitive resist after finishing of film hardening, and adjusting process conditions in the film hardening process based on the optical density. CONSTITUTION: A shadow mask material 1 is of low carbon steel having plate thickness of 0.13mm or low expandable invar material. Water soluble photosensitive liquid composed of polyvinyl alcohol and ammonium dichromate is used as a photosensitive resist 2 so as to provide the shadow mask material 1 having a fine hole resist film 2a and a large hole resist film 2b of each film thickness 10μm on the obverse and reverse sides. Next, chromic acid anhydride solution is used as a film hardening treatment liquid 8 in a film hardening treatment tank 7, and after a mask material is dipped in, buring is conducted via a far infrared radiation heater 9. Reflection density C of the mask material 1 is measured from the fine hole side by using an optical reflection density meter 10. A measured value C is compared with a reference value and in accordance with the result, concentration of the photosensitive liquid is adjusted.

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 used for a color picture tube.

[0002]

2. Description of the Related Art A conventional example of a method for manufacturing a shadow mask used for a color picture tube by a photoetching method will be briefly described with reference to FIG. First, for example, a roll-shaped thin plate metal material that becomes the substrate material of the shadow mask is used, and the thin metal plate is attached to the surface of the metal plate (hereinafter referred to as the shadow mask material) by contacting with an alkaline degreasing liquid. A degreasing process is performed to remove oil and organic debris that are present. Then, in the next step of applying the photosensitive resist, the surface of the shadow mask material is adjusted by contacting the shadow mask material with an acid treatment liquid so that the photosensitive resist is easily attached to the surface of the shadow mask material. Perform surface treatment.

Then, for example, a negative photosensitive resist 2 is applied to both surfaces of the shadow mask material 1. Then, FIG.
As shown in (a), using a pattern mask 6 of two kinds of large holes and small holes having a hole-shaped pattern portion as a light-shielding portion, the small hole pattern mask 6a is closely adhered to one surface of the metal plate, The large-hole pattern mask 6b is closely applied to the other side at the corresponding position, and the both sides are simultaneously irradiated with ultraviolet light to perform pattern printing, thereby photo-curing the photosensitive resist 2 in the area other than the hole-shaped pattern portion. To do.

Next, the unexposed and uncured photosensitive resist 2 is removed by developing with, for example, a hot water spray, and then, as shown in FIG.
(B) is obtained. Then, a process of hardening the remaining photosensitive resists 2a and 2b, for example, a process of contacting the processing liquid with the shadow mask material by immersing the shadow mask material in the film processing liquid and then performing burning, for example, is performed. .

Next, as shown in FIG. 3C, both surfaces of the shadow mask material 1 are subjected to primary etching, and both surfaces of the shadow mask material 1 are subjected to constant etching. Then, FIG.
As shown in (d), a varnish is applied to the small hole side to form the etching prevention layer 4. Next, as shown in FIG. 3 (e), secondary etching is performed on the large hole side to penetrate the small hole to form the concave hole 5
Get. Next, as shown in FIG. 3F, after removing the etching prevention layer 4 and the photosensitive resists 2a and 2b using an alkaline solution, unnecessary portions of the shadow mask material 1 are removed to form a shadow mask.

In this conventional method, it can be said that the side etching phenomenon, which cannot be avoided by the photo etching method, is suppressed on the small hole side. That is, by filling the recesses on the small hole side with the etching prevention layer and not side-etching the small holes in the second etching step, the accurate small hole pattern in the first etching step can be maintained. Therefore, for example, it is possible to open a hole having a hole diameter smaller than the thickness of the material metal plate.

However, this conventional method is not without problems. That is, if the treatment is insufficient in the film-hardening step, the etching resistance of the resist and the adhesion of the resist to the shadow mask material are deteriorated, and the shape of the shadow mask is defective in the etching treatment in the next step. Is.

That is, since the etching resistance of the resist after the film hardening process is deteriorated, the etching solution permeates into the resist film and contacts the shadow mask material during the etching process, so that unnecessary etching is performed on the shadow mask material. May occur, resulting in a pattern abnormality or pinhole, resulting in, for example, a hole-shaped defective shape 11 as shown in FIG.
Further, the adhesion of the resist to the shadow mask material after the hardening treatment is deteriorated, so that the resist is peeled off from the shadow mask material during the etching step, and the peeled resist is attached to the shadow mask material on other parts, By inhibiting the etching of the portion, for example, the pattern chip 12 as shown in FIG. 2 may occur.

Further, if the treatment is excessively performed in the film-hardening process, the resist is hard and adheres strongly to the shadow mask material. Therefore, even if the resist is stripped after the etching process is completed, the resist remains on the shadow mask. There is also a problem that the resist remains, which causes rust on the shadow mask.

The following cases may be examples of insufficient treatment in the film-hardening step after the developing step. That is, the concentration of the treatment liquid used for hardening treatment is out of the specified value, or the treatment liquid is fatigued. Further, in burning, a case where the burning temperature deviates from the specified temperature can also be mentioned.

Normally, the processing conditions such as the concentration of the processing solution and the burning temperature in the film hardening process are inspected at the start of the production of the shadow mask and periodically. However, since the shadow mask is continuously manufactured from a roll-shaped metal material as described above, it needs to be inspected at any time, but it can be said that it is difficult to carry out because of labor, cost, and the like.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a shadow mask used in a color picture tube, and more particularly to provide a method for manufacturing a shadow mask which does not have the above-mentioned problems. is there.

[0013]

That is, the present invention provides a pattern exposure step of baking a predetermined pattern on the front and back of a shadow mask metal material having a photosensitive resist layer formed on both sides, and a photosensitivity of an unexposed portion. A shadow mask for a color picture tube using a photo-etching method, which has a developing step for removing the resist, performs a film forming step for the photosensitive resist remaining after the developing step, and then performs an etching step for the shadow mask material, etc. In the method for manufacturing a shadow mask, the optical density of the photosensitive resist after the hardening step is measured, and the processing conditions in the hardening step are adjusted based on the optical density. This solves the above problems.

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows a main part of an example in which the present invention is carried out in manufacturing a shadow mask.

In FIG. 1, a shadow mask material 1 is a long metal plate supplied from a winding roll, and is made of, for example, low carbon steel having a plate thickness of 0.13 mm or low expansion amber material. The development process is performed according to the process already described in the section of (Prior Art) to obtain the shadow mask material 1 having the small hole side resist 2a and the large hole side resist 2b on the front and back sides as shown in FIG. 3B.

Then, in the film hardening step, for example, as shown in FIG. 1, after passing the shadow mask material 1 through the film hardening processing bath 7 and bringing the shadow mask material into contact with the film hardening processing liquid 8, for example, a far infrared heater. Burn by passing through 9.

The inventors of the present invention have found that when the processing conditions in the film-hardening process after photocuring are proper and the hardened resist has proper hardness, the optical density of the resist is We empirically obtained the fact that if the thickness is constant, it will always be within a fixed range for each type of resist, and we paid attention to this.

Therefore, in the present invention, as shown in FIG. 1, for example, an optical reflection densitometer 10 is used for the shadow mask material 1 for which the hardening process has been completed, and the shadow mask material 1 is optically reflected from above the resist. It is characterized in that the concentration is measured, and the treatment conditions in the film hardening step are adjusted based on the obtained measured values. In the subsequent steps, the shadow mask is manufactured by performing the conventional etching step and the like.

The above-mentioned optical reflection density is defined as the optical reflection density with D represented by the following (Equation 1) when the intensity of incident light is I ₀ and the intensity of light reflected from an object is I _1. did.

[0020]

[Equation 1]

It is desirable that the optical reflection density of the shadow mask material is measured at a solid portion where the photo-cured resist film spreads uniformly, avoiding the location where the hole pattern is formed. By the way, in Examples described later, the measurement was carried out at a solid portion where the photo-cured resist film spreads uniformly in the middle between the shadow masks continuously formed on the strip-shaped shadow mask material. Further, the surface to be measured is the surface of the small hole side resist 2a in FIG. 1, but if the coating film thickness of the resist is the same on both surfaces of the shadow mask material, it is measured on which surface of the shadow mask material. Alternatively, for example, the surface of the large hole side resist 2b may be used. However, when the coating thickness of the resist is different on both sides, it is desirable to measure on the surface of the shadow mask material described below, which has the same coating thickness as the reference resist thickness.

Further, the present invention will be described. First, the optical reflection density of the resist alone in the case of the same type and the same film thickness as that applied in the production of the shadow mask, and the case where the film hardening process is appropriately performed in the film hardening step after photocuring, This is designated as A. As described above, the value of A is always within a fixed range for each type of resist if the film thickness is the same. The reason why A has a certain range is, for example, a variation in the coating film thickness within the tolerance when the photosensitive resist is coated, a tolerance of the hardness of the resist after the hardening step, and the like. Then
The optical reflection density of the surface of the shadow mask material 1 alone which is not coated with the resist 2 on the surface is examined, and this is designated as B.

Then, in accordance with the usual shadow mask manufacturing process, the optical reflection density of the shadow mask material 1 which has been coated with the resist and completed the hardening process is measured from above the resist, and the obtained optical reflection density measurement value is obtained. Let be C. Then, by subtracting B from C, the optical density D of the resist after the hardening process is obtained.

Then, by using A as a reference value and comparing with D, it is judged whether or not the treatment in the hardening step is possible. Also, a method of comparing with C using the value E obtained by adding A and B as a reference value can be used. The above-mentioned reference value is accompanied by some error because A has a certain range as described above. This error depends on the tolerance of the coating thickness of the photosensitive resist and the resist after hardening. It can be said that it is desirable to appropriately set it in accordance with manufacturing conditions such as the allowable error of hardness. Incidentally, in the examples described later, the error of the reference value E is empirically set to ± 0.05.

Next, in the present invention, the processing conditions in the film hardening step are adjusted by comparing the above values.

The following examples can be given to adjust the processing conditions in the film hardening process. That is, when the measured value obtained after the film hardening step is lower than the reference value, it is considered that the resist film is insufficiently hardened, and adjustment is made to accelerate the film hardening process. For example, when a chemical solution is used for the dura mater treatment, at least one of increasing the concentration of the chemical solution, raising the burning temperature, and prolonging the treatment time can be considered. On the contrary, when the measured value is higher than the reference value, it is considered that the resist is hardened excessively, and adjustment is made to suppress the hardening treatment. For example, in the case of using a chemical solution for the dura treatment, at least one of reducing the concentration of the chemical solution, lowering the burning temperature, and shortening the treatment time can be considered.

Although the above description is based on a high-definition shadow mask using an etching prevention layer,
It goes without saying that the present invention can be applied to the step of hardening the photosensitive resist even in the case of using a slot type shadow mask without using the etching prevention layer.

[0028]

By using the present invention, the resist film is appropriately hardened by measuring the optical density of the shadow mask material, for example, the optical reflection density after the hardening process in the shadow mask manufacturing method. Whether or not it can be determined. As a result, it becomes possible to quickly adjust the dura treatment conditions. For this reason, it is possible to prevent a defective etching shape of the shadow mask due to a defective film processing, which has occurred in the conventional method, and a rust due to a resist residue after the film removal.

Further, once the reference value is determined, even if the shadow mask is continuously manufactured, it is possible to obtain the adjustment conditions for the hardening treatment at any time by continuously measuring the optical density. Becomes Therefore, for example, it becomes unnecessary to frequently measure the chemical concentration of the treatment liquid as in the conventional case, and the labor and cost required for the measurement can be reduced.

[0030]

EXAMPLES Examples of the present invention are shown below. <Example> An alloy material (amber material) having a thickness of 0.13 mm and iron and nickel as main components is used as a shadow mask material 1, and a photosensitive resist 2 is made of a water-soluble photosensitive solution composed of polyvinyl alcohol and ammonium dichromate. I was there. Then, the development process is performed according to the process described in the above (Prior art), and a film thickness of 10 μm is obtained as shown in FIG.
A shadow mask material 1 having a small-hole resist film 2a of m 2 and a large-hole resist film 2b on the front and back sides was obtained.

Then, as shown in FIG.
A chromic anhydride solution having a concentration of 30 g / l was used as the hardening solution 8 in the above, and the shadow mask material 1 was immersed for 30 seconds and then the temperature was changed to 150
Burning was carried out by passing through the far-infrared heater 9 in an atmosphere of ° C for 5 minutes. Then, after completion of the film-hardening process, the optical reflection density of the surface of the shadow mask material 1 was measured from the small hole side using a "Macbeth reflection densitometer" manufactured by Sakata Engineering Co., Ltd. according to the present invention. 1.78 was obtained as the optical reflection density measurement value C described in the section of (Means for solving).

Prior to the production of the shadow mask, the optical reflection density of the raw shadow mask material alone before the application of the photosensitive resist and the same kind and the same film thickness as those used for the above shadow mask material were used. The optical reflection density of the resist alone when the hardening treatment was properly performed in the hardening step after photocuring was measured by using a product name "Macbeth reflection densitometer" manufactured by Sakata Engineering Co., Ltd. as described above. This gives an optical reflection density value of 1.08 and
Since 0.78 was obtained, the reference value E described in the above section (Means for solving the problem) was set to 1.86 ± 0.05.

Next, the obtained optical reflection density was compared with the reference value and the measured value was low. Therefore, the concentration of the chromic anhydride solution was adjusted to 32 g / l in order to accelerate the hardening treatment. Optical reflection density measurement value C after adjustment of this hardening solution
Became 1.85.

Then, according to the conventional process, the steps after the etching step were performed to obtain a shadow mask. In addition, when the shadow mask obtained after the preparation of the hardening solution was examined, no etching shape defect due to insufficient hardening process or a defect such as resist residue due to excessive hardening process was observed.

[0035]

By using the present invention, the optical density of the shadow mask material, for example, the optical reflection density is measured after the completion of the hardening process in the shadow mask manufacturing method using the photoetching method. Whether or not the dura mater treatment was properly performed can be determined. As a result, it is possible to perform proper dura treatment by promptly adjusting the dura treatment conditions. For this reason, it is possible to prevent the etching shape defect of the shadow mask due to the defect of the hard film, which is caused by the conventional method, and the rust due to the resist residue after the film peeling.

Further, once the reference value is determined, even if the shadow mask is continuously manufactured, the optical density is continuously measured by using, for example, a computer or the like, so that the dura matter can be continuously obtained. It is possible to obtain the adjustment condition of the treatment and to adjust the dura treatment. Therefore, it can be said that the present invention is practically excellent in that it is easy to always obtain a resist having a proper hardness, that is, a proper optical reflection density.

[0037]

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing an example of an etching shape defect of a shadow mask due to a defect of a film hardening process.

3A to 3F are explanatory views showing an example of a method of manufacturing a shadow mask in the order of steps.

[Explanation of symbols]

 1 Shadow Mask Material 2 Resist 3 Concave 4 Etching Prevention Layer 5 Recessed Hole 6 Mask 7 Hardening Treatment Tank 8 Hardening Treatment Liquid 9 Heater 10 Optical Reflection Densitometer 11 Defect 12 Pattern Missing

Claims (2)

[Claims] 1. A pattern exposure step of baking a predetermined pattern on the front and back of a shadow mask metal material having a photosensitive resist layer formed on both sides, and a developing step of removing the photosensitive resist in an unexposed area. In the method for producing a shadow mask for a color picture tube using a photo-etching method in which a film-hardening process of the photosensitive resist remaining after the developing process is performed, and then an etching process to the shadow mask material is performed, A method for producing a shadow mask, which comprises measuring an optical density of a photosensitive resist and adjusting processing conditions in a film hardening step based on the optical density. 2. The optical density is an optical reflection density.
A method for manufacturing the shadow mask described.