JP3414076B2 - Inspection method of shadow mask - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a shadow mask in which a hole penetrating a metal plate is opened according to a predetermined pattern, and in particular, an opening shape provided in a resist film formed on a metal material. Regarding inspection.

[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 shown in FIG. 7, for example. A metal material, that is, a low carbon steel plate having a thickness of 0.13 mm is used as the shadow mask material 1, and both surfaces thereof are degreased, surface-treated,
After the cleaning treatment, a water-soluble photosensitive solution composed of casein or polyvinyl alcohol and ammonium dichromate is applied on both surfaces and dried to form a photoresist film 2 (hereinafter referred to as a resist film). Then, the resist film 2 is pattern-exposed on one surface of the shadow mask material 1 through a positive exposure pattern mask for a small hole image and on the other surface through a large hole image positive exposure pattern mask. After that, a developing process for dissolving the unexposed and uncured resist film is performed with warm water, and then a hardening process and a burning process are applied to the resist film 2 to form a predetermined pattern as shown in FIG. A shadow mask material 1 having a small-hole resist film 2a having an opening 3a and a large-hole resist film 2b having an opening 3b provided on the front and back sides is obtained.

Next, the first stage etching is performed from both front and back surfaces. As the etching solution, a Baume concentration of ferric chloride solution of 35 to 50 is generally used, and spray etching is generally performed at a spray pressure of 1.5 to 3.5 kg / cm ² . In this first etching step, as shown in FIG. 7B, it is important to stop the etching progress on the way.

Next, after the shadow mask material 1 is washed with water and dried, as shown in FIG. 7 (c), an etching prevention layer 4 is formed which completely fills the small-hole-side concave portion formed by the preceding etching. . Subsequently, as shown in FIG. 7D, a second etching step of etching the shadow mask material 1 only from the large hole side is performed to form an opening 9 penetrating from the large hole side to the small hole. Finally, the etching prevention layer 4
Then, the resist film 2 is peeled off, washed with water and dried, and then, as shown in FIG.
The flat type shadow mask 5 shown in FIG. Depending on the type of shadow mask, the opening 9 may be formed only by the etching process without forming the above-mentioned etching prevention layer 4.

In a shadow mask used for a color picture tube or the like, a large number of small-diameter penetrating openings 9 are formed.
The shape of the opening 9 to be formed on the shadow mask is preset in the design stage before manufacturing the shadow mask, and the shape is desired when the shadow mask is incorporated in the color picture tube or the like. It is set so that it can exhibit its performance. Therefore, whether or not the opening 9 formed in the manufactured shadow mask has a shape as set in advance depends on whether or not a color picture tube in which the shadow mask is incorporated can exhibit desired performance. It can be said to be an important factor that influences.

As shown in the above-mentioned example of FIG. 7A, before the etching for forming the desired opening 9 in the shadow mask material 1, an opening 3 having a partially metal surface exposed according to a predetermined pattern is formed. Forming a resist film 2 having
By etching the shadow mask material using this resist film 2 as an etching resistant layer, the resist film 2
A portion of the shadow mask material 1 exposed through the opening 3 (hereinafter simply referred to as the opening 3) provided in the shadow mask material 1 is selectively etched to form a desired pattern, for example, the opening 9 in the shadow mask material 1. Becomes

Therefore, the opening 3 has a pattern defect in the exposure pattern mask used for pattern exposure, or foreign matter adheres to the roller for carrying the shadow mask material 1 to scratch the resist film 2. Therefore, it can be said that the opening 9 formed by perforating the shadow mask material 1 does not have the desired shape when the opening 3 does not have the desired shape. That is, it can be said that it is essential that the opening 3 has an opening having a desired shape. By the way, as a pattern defect of the exposure pattern mask,
When the exposure pattern mask is manufactured, the pattern on the mask may be missing, or an extra pattern may be formed on the pattern mask. Foreign matter adheres,
There is also a case where a foreign substance becomes a shadow during pattern exposure.

Usually, a shadow mask material 1 supplied in a long strip shape from a metal roll is used to continuously manufacture shadow masks. For example, when a defective exposure pattern mask is used, the shadow mask material is commonly used at the same location. A large number of shadow masks in which the openings 9 having poor shape are perforated are manufactured. A shadow mask with perforated defective openings 9 is difficult and often discarded. Therefore, it is necessary to remanufacture the shadow mask anew, resulting in loss of material and materials due to remanufacturing and a burden on the manufacturing process.

Therefore, it is inspected at an early stage whether the opening 3 has a desired shape or whether the resist film 2 on each shadow mask material has a common flaw. It is necessary to take measures such as changing and cleaning the pattern mask for cleaning, or cleaning the roller for conveying the shadow mask material. However, it is difficult to inspect the shape of the opening 3 for the reason described below. Therefore, for example, due to a defect of the exposure pattern mask, the resist film 2 on each shadow mask material is formed in the same location in common. Even if it has a hole 3 with a bad shape, conventionally, it was
The common flaw was discovered. In particular, depending on the type of shadow mask, secondary etching may be performed, so it takes a long time to find a defect, and at the time of finding a defect, many shadow mask materials having common defects were often etched. .

That is, it is conceivable to inspect the shape of the opening 3 by using a microscope or the like with human eyes. However, since the resist film 2 is formed with a large number of fine holes, it cannot be said that it is impossible for a person to inspect all the holes, and even if it is performed, the inspection leaks and the efficiency is low. For that reason. Therefore, mechanical inspection using an automatic inspection machine has also been proposed.

Incidentally, the automatic inspection machine inspects the shape as follows, for example. That is, as shown in the example of FIG. 6, for example, a high-frequency fluorescent lamp or the like is used as a light irradiation unit, that is, a light source 6 is used to irradiate the shadow mask material 1 with light.
The light reflected from the light irradiation portion is received as an optical image by a solid-state imaging camera or the like as a measuring means 7 for measuring the appearance of the surface of the resist film provided on the same side as the light source 6, and this optical image is converted into an electric signal. After the conversion, the electrical signal is received by the determination means 11 such as a computer, and the determination means 11 is for inspecting and determining whether the hole is a desired one or a flaw. At the time of the shape inspection, a comparative inspection method is generally used for the shadow mask material 1 having the openings 3 arranged according to a certain pattern. That is, this is a method in which the shapes of a plurality of adjacent openings 3 in a certain area are compared to extract an opening 3 having a shape different from that of another opening 3 as a defect. This is performed for the entire area where the openings of the shadow mask material that will be the shadow mask are formed. When moving the inspection site, the light source 6 and the measuring means 7 are moved in conjunction with each other, or the shadow mask material 1 is moved. A series of inspection and movement processing is performed by the determination means 11, for example. It is controlled.

However, even in the inspection using the above-described automatic inspection machine, the shape inspection of the opening 3 has many errors and is unreliable for the following reasons, and the shape inspection of the opening 3 is difficult. That is, when the shadow mask material 1 is manufactured from a metal material, the metal material is rolled with a roller or the like to have, for example, a long strip shape. At that time, as shown in the plan view of FIG. For example, a streak-like or spot-like pattern 8 is formed.

In many cases, the resist film 2 formed on the shadow mask material 1 is in a semitransparent state, and the surface of the shadow mask material 1 on the lower surface is seen through the resist film 2 as shown in the plan view of FIG. The pattern 8 is visible. That is, it can be said that the resist film 2 transmits the irradiation light from the above-described automatic inspection machine, and the contrast between the surface of the shadow mask material 1 exposed from the opening 3 and the surface of the resist film 2 is low.

When the surface of the shadow mask material 1 is irradiated with light from the light source 6, the above-mentioned pattern 8 looks particularly emphasized at the light-irradiated portion, so that the outline of the opening 3 is buried in the pattern 8, and However, even if the optical image on the surface of the shadow mask material is measured by using the measuring means 7 including, for example, a solid-state imaging camera, it is difficult to clearly capture the shape of the three openings. Therefore, it can be said that the shape inspection by the automatic inspection machine is impossible, and even if the shape inspection is performed, it is often determined that the shape of the opening 3 formed in the desired shape is defective, and Even if the resist film 2 was scratched and an unnecessary opening was generated, it was overlooked and the reliability was low.

[0015]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention can easily inspect whether a resist film formed on a shadow mask material is provided with openings as desired. The present invention is intended to provide a shadow mask inspection method that has no inspection error in the shadow mask inspection and has improved inspection efficiency.

[0016]

That is, according to the present invention, there is provided a step of coating and forming a photosensitive resin layer on a plate-shaped metal material,
A step of pattern-exposing the photosensitive resin layer through an exposure pattern mask, and exposing the photosensitive resin layer to expose a part of the metal surface according to a predetermined pattern, and then performing a hardening treatment and a burning treatment to form a resist. Shadow mask inspection method obtained by at least performing a resist film forming step of forming a film and an etching step of forming a hole penetrating a metal material according to a predetermined pattern by etching a metal surface exposed from the resist film In the step of, after the resist film forming step, the metal material is provided at two symmetrical positions on the same side of the metal material, and the metal material surface is substantially parallel to the direction of rolling performed when the metal material is manufactured. A light irradiating means for irradiating light to substantially the same part of the metal material surface from an obliquely upper direction, and a front part provided above the light irradiating part. It is characterized by comprising means for measuring the appearance of the resist film surface at the light irradiation site, and means for judging from the measurement results whether the openings formed in the resist film satisfy the desired shape. The above problem is solved by providing a method for inspecting a shadow mask.

Further, as a modification of the present invention, after the resist film forming step, means for smoothing the surface of the metal surface exposed from the openings of the resist film to smooth the surface, and metal plating the surface of the metal surface A means for forming an identification layer having a smooth and high reflectance and, after metal plating treatment, provided at two positions symmetrical with each other on the same surface side of the metal material, and rolling performed when manufacturing the metal material. Light irradiation means for irradiating light on substantially the same portion of the metal material surface from a direction substantially parallel to the direction of the metal material and obliquely above the metal material surface, and a resist film of the light irradiation portion provided above the light irradiation portion. A method for inspecting a shadow mask, comprising: a means for measuring the appearance of the surface; and a means for determining, from the measurement result, whether or not the openings formed in the resist film satisfy a desired shape. Can also be on It said effective as means for solving the problems.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be described below.
explain. The inventors of the present invention have made earnest studies to achieve the above-mentioned object, and first focused on the pattern 8 on the surface of the shadow mask material 1, which makes inspection by an automatic inspection machine difficult. As described above, the stripe-like or spot-like pattern 8 on the surface of the shadow mask material 1 is formed during rolling of the metal material, but the pattern 8 is formed by collecting fine irregularities. The irregularities have a common shape part depending on the rolling direction of the metal material.
That is, as shown in FIG. 4, each unevenness 12 on the surface of the shadow mask material 1 is a side wall 13 which is a surface substantially parallel to the rolling direction.
In the automatic inspection, it is presumed that the irradiation light emitted from the light source 6 hits the side wall 13 to cause a shadow or light reflection, whereby the pattern 8 is emphasized during the light irradiation. is there. In FIG. 4, the rolling to the shadow mask material 1 is performed in the direction perpendicular to the paper surface.

Therefore, the present inventors have reached the present invention by paying attention to the light irradiation direction at the time of light irradiation, because each unevenness 12 has a common shape portion corresponding to the rolling direction as described above. Is. That is, since the side wall 13 of each unevenness 12 is a surface in a direction substantially parallel to the rolling direction, it can be said that the irradiation light does not strike the side wall 13 if light irradiation is performed in a direction substantially the same as the rolling direction. As a result, when using conventional light irradiation,
The present invention is based on the presumption that the pattern 8 is not emphasized due to the fact that the wall surface 13 does not cause a shadow or light reflection.

FIG. 1 is an explanatory view showing an embodiment of the present invention. The shadow mask material 1 in the figure has a resist film 2 in which openings 3 have been formed after completion of the film hardening process in accordance with the steps described in the above (Prior Art). In the inspection of the opening shape formed in the resist film 2, light irradiation is performed on the surface of the shadow mask material 1 by using, for example, a high-frequency fluorescent lamp as a light source 6, and the contour shape of the opening 3 at the light irradiation portion is determined as in the conventional light source. 6, which is provided above the light irradiation site on the same surface as 6, and receives as a light image by a measuring means 7, such as a solid-state imaging camera, which measures the appearance of the resist film surface of the light irradiation site, and converts this light image into an electric signal. After that, an electric signal is received by the judging means 11 such as a computer, and the judging means 11 is for judging whether the hole is a desired one or a flaw.

The inspection determination method of the automatic inspection machine is, for example, the comparative inspection method described in the section (Prior Art). That is, by comparing the contour shapes of a plurality of adjacent openings 3 in a certain area, for example, the light irradiation area, a method of extracting an opening 3 having a different contour shape from other openings 3 as a defect. This is done for all areas of the shadow mask for which shape inspection is required. Further, when moving the inspection site, the light source 6 and the measuring means 7 are interlocked with each other and moved on the shadow mask material 1 by a driving means (not shown), or the positions of the light source 6 and the measuring means 7 are moved. The shadow mask material 1 is fixed and moved by a driving means (not shown), and a series of inspection and movement processes are controlled by the judging means 11, for example.

Here, in the inspection method of the present invention, as shown in FIG. 1, the light source 6 is set in a direction substantially the same as the rolling direction performed when the shadow mask material 1 is manufactured and at an angle to the surface of the shadow mask material 1. It is provided in the upper direction. Further, the light source 6 is provided at two symmetrical positions on the same surface of the metal material,
Light irradiation is performed on substantially the same portion of the surface of the shadow mask material.

As described above, by irradiating the light in the same direction as the rolling direction performed when the shadow mask material 1 is manufactured, the unevenness 12 formed during rolling is approximately the same as the rolling direction. The side wall 13 which is a parallel surface is not directly exposed to light, and the side wall 13 does not cause a shadow or light reflection.
Is not emphasized. This makes it possible to capture the contour shape of the openings 3 formed in the resist film 2.

Further, light irradiation is performed obliquely above the surface of the shadow mask material 1. If the irradiation angle X on the surface of the shadow mask material 1 is small, the incident light is likely to be specularly reflected on the surface of the shadow mask material. The amount of light that goes upward on the surface of the shadow mask material 1 decreases, and it becomes difficult for the measuring means 7 to capture an optical image. Further, when the surface of the shadow mask material 1 is vertically irradiated with light, the pattern 8 on the surface of the shadow mask material 1 is emphasized, and it is difficult to distinguish it from the contour shape of the three openings. Therefore, the present inventors have empirically found that the light irradiation angle X on the surface of the shadow mask material 1 is preferably 15 ° or more and less than 90 °.

Next, in the present invention, as shown in FIG.
On the same side of the shadow mask material 1, the shadow mask material 1
The light sources 6 are provided at two positions that are symmetrical with respect to the light irradiation site on the surface. With each of the light sources 6, from the direction substantially parallel to the rolling direction of the shadow mask material 1 and the obliquely upward direction of the surface of the shadow mask material 1, the shadow mask material 1 surface is substantially the same portion and substantially the same as the shadow mask material 1 surface. The light irradiation is performed at the incident angle X of. That is, as described above, since the resist film 2 is in a semitransparent state in many cases, the openings 3 and the shadow mask material 1 exposed from the openings 3 are formed.
It was difficult to distinguish from the surface. Therefore, as shown in FIG. 2, by irradiating light from two oblique directions, the side surface 14 of the opening 3 formed in the resist film 2 is not shaded, and the side surface 14 is reflected over the entire circumference. To shine and then open hole 3
The contour of the open area 3 has contrast, and the contour shape of the opening 3 becomes clearer. As a result, the automatic inspection machine easily identifies the contour of the opening 3 in the resist film 2.

Next, the inventors of the present invention have already exposed the shadow mask material 1 exposed through the openings 3 formed in the resist film 2.
It proposes a conventional automatic inspection method after the surface is trimmed and the exposed area is metal-plated.
Using this method, the surface of the shadow mask material 1 exposed from the openings 3 is surface-aligned, the exposed portion is metal-plated, and then the inspection according to the present invention shown in FIG. 1 is performed. It can be said that it is effective as a means.

That is, when the resist film 2 is semitransparent,
Since the contrast between the surface of the shadow mask material 1 exposed from the opening 3 and the surface of the resist film 2 is low, metal plating is performed on the portion of the opening 3 to provide contrast between the portion of the opening 3 and other surface of the shadow mask material. The outline shape of the opening 3 is clarified, and will be described below with reference to the drawings.

The method of conducting the inspection after the metal plating is performed is a sampling inspection from a continuous long strip-shaped shadow mask material. First, pre-etching is performed on the shadow mask material 1 extracted from the manufacturing process and having the resist film 2 having the openings 3 shown in FIG. 3 (a), and as shown in FIG. The shadow mask material 1 part exposed from 3 parts is subjected to surface conditioning. As described above, the surface of the shadow mask material 1 has minute irregularities. As will be described later, in the present invention, the portion of the shadow mask material 1 exposed from the three holes is metal-plated. As a result, the metal plating surface also has irregularities. Therefore, the shadow mask material 1 exposed from the openings 3 is subjected to pre-etching, that is, etching is performed slightly to adjust the surface to dissolve and remove the minute irregularities on the surface to form a smooth exposed surface.

Next, the shadow mask material 1 is subjected to metal plating, such as electroplating, to expose the shadow mask material 1 from the openings 3, that is, the resist film 2 as shown in FIG. 3C. Metal plating is applied to only one site, and a metal plating layer 10 having a smooth surface and high reflectance is provided as an identification layer.

Next, for the shadow mask material 1 on which the metal plating has been completed, as described in the description of FIG. 1 above,
The inspection is performed by irradiating light from substantially the same direction as the rolling direction performed when the shadow mask material 1 is manufactured and two directions obliquely above the surface of the shadow mask material 1.

The metal plating layer 10 having a smooth surface and a high reflectance efficiently reflects the radiated light and shines to emphasize the contrast between the resist film and the plated portion, that is, the opening portion area of the resist film. The holes 3 and other resist film parts can be easily distinguished, and the pattern of the shadow mask material 1 surface other than the holes 3 parts can be obtained by irradiating light in the same direction as the rolling direction. 8 becomes unnoticeable. Moreover,
As described above, by irradiating light from two oblique directions, the side surface 14 of the opening 3 is not shaded, and the side surface 14 reflects and shines over the entire circumference, so that the contour shape of the opening 3 is clearer. It will be. As a result, the automatic inspection machine can easily identify the contour of the opening 3 in the resist film 2.

The embodiment of the method for inspecting a shadow mask according to the present invention is not limited to the above-mentioned embodiment shown in FIG. 1, and various modifications may be made based on the spirit of the present invention. Needless to say. For example, although only one surface of the shadow mask material 1 is shown in FIG. 1 for simplification of description, it can be said that the same inspection may be performed on both surfaces of the shadow mask material 1.

[0033]

In the method for inspecting a shadow mask of the present invention, the pattern 8 on the surface of the shadow mask material 1 is made inconspicuous by irradiating the light in a direction substantially the same as the rolling direction, and the pattern 8 is inclined in two directions. By illuminating and clarifying the outline of the opening 3 by reflection, the automatic inspection machine can easily identify the outline shape of the opening 3 of the resist film 2,
For the shape inspection of the openings 3 provided in the resist film 2, it is possible to use, for example, a comparative inspection type automatic inspection machine.

Therefore, the shape of the opening 3 formed in the resist film 2 can be mechanically inspected, so that the inspection efficiency and inspection accuracy are improved, and there is no inspection leakage that occurs when the inspection is performed manually. Further, the inspection can be performed without being influenced by the skill of the inspector.

Further, conventionally, it was difficult to inspect the shape of the opening 3 formed in the resist film 2. Therefore, even if the resist film has an opening having a defective shape due to, for example, a defect of the exposure pattern mask, In many cases, the defect was discovered after the final etching step, and many shadow mask materials 1 having common defects were already etched at the time of finding the defect. However, in the present invention, before the etching step,
When the resist film having holes is formed, the shape of the holes formed in the resist film can be inspected, and when a defect is found, it is possible to quickly remove the defect. Therefore, it can be said that the loss of material and the burden on the manufacturing process, which have occurred conventionally, can be prevented.

Further, conventionally, even if a defect is found after the etching process, it is difficult to judge whether the defect is due to a defective opening of the resist film 2 or due to other factors such as a factor in the etching process. However, in the present invention, by inspecting the holes formed in the resist film, the shadow mask material having a resist film having no defect can be flowed in the etching process. As a result, it is possible to judge that the defects found after etching are caused by factors in the etching process, and it is possible to prevent defects, that is, to narrow down the range of process improvement, so that it is possible to take prompt measures. It can be said that the present invention is practically excellent in obtaining a good shadow mask.

[0037]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main part of an embodiment of a shadow mask inspection method according to the present invention.

FIG. 2 is an explanatory cross-sectional view showing a main part of an embodiment of a shadow mask inspection method according to the present invention.

FIGS. 3A to 3C are explanatory views showing a main part of another embodiment of the method for inspecting a shadow mask according to the present invention in the order of steps.

FIG. 4 is an enlarged cross-sectional view showing an example of unevenness formed on a shadow mask material.

FIG. 5 is an explanatory plan view showing an example of a pattern on the surface of a shadow mask material.

FIG. 6 is an explanatory diagram showing an example of the principle of an automatic inspection machine.

7A to 7E 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 film 3 holes 4 Etching prevention layer 5 shadow mask 6 light source 7 Measuring means 8 patterns 9 openings 10 Metal plating layer 11 Judgment means 12 unevenness 13 Side wall 14 sides

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Claims (2)

(57) [Claims] 1. A step of coating and forming a photosensitive resin layer on a plate-shaped metal material, a step of performing pattern exposure on the photosensitive resin layer through an exposure pattern mask, and a step of developing the photosensitive resin layer. After a part of the metal surface is exposed according to a predetermined pattern, a resist film forming step of performing a hardening process and a burning process to form a resist film, and a metal surface exposed from the resist film is etched to form a metal according to the predetermined pattern. In a shadow mask inspection method obtained by performing at least an etching step of forming a hole penetrating a material, after the resist film forming step,
The metal material surface is provided at two symmetrical positions on the same side of the metal material, and is substantially parallel to the direction of rolling performed when the metal material is manufactured and diagonally above the metal material surface. Light irradiation means for irradiating light to substantially the same portion, a means for measuring the appearance of the resist film surface of the light irradiation portion provided above the light irradiation portion, and from the measurement result,
A method for inspecting a shadow mask, comprising: a means for determining whether an opening formed in a resist film has a desired shape. 2. A means for smoothing the surface of a metal surface exposed from the opening of the resist film by smoothing the surface after the resist film forming step, and metal plating the surface of the metal surface for smooth surface and high reflectance. Means for forming an identification layer, and after metal plating treatment,
The metal material surface is provided at two symmetrical positions on the same side of the metal material, and is substantially parallel to the direction of rolling performed when the metal material is manufactured and diagonally above the metal material surface. Light irradiation means for irradiating light to substantially the same portion, a means for measuring the appearance of the resist film surface of the light irradiation portion provided above the light irradiation portion, and from the measurement result,
The shadow mask inspecting method according to claim 1, further comprising means for determining whether or not the openings formed in the resist film satisfy a desired shape.