JPH07107828B2 - Method for forming etching through holes in thin steel plate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming a hole in a thin steel plate by etching, for example, a method for manufacturing a thin shadow mask for a CRT such as a color television having a thickness of about 20 to 80 .mu.m.

[0002]

2. Description of the Related Art In recent years, along with the increase in the size of CRT display devices such as color televisions, the shadow mask has also been required to be increased in size. In order to reduce the weight of the shadow mask itself, a thin plate of about 20 to 80 μm has been used.

By the way, the conventional plate thickness of 100 to 300 μm
As a method of manufacturing a shadow mask using the base material of FIG. 2, as shown in FIG. 2, the electrode base material 1 is washed (a), and then the resist 2 is applied to both surfaces of the base material 1 (b), Of the resist 2 is exposed using the glass mask 3 (c), and then the resist 2 is developed and patterned, and dried to form an etching film (d), and then both sides of the substrate 1 are simultaneously etched to form openings. After the formation (e), the resist 2 is peeled off (f) A method of manufacturing by one-step etching is known, but when this method is applied to a thin plate base material of about 20 to 80 μm, the spray pressure during etching is Affected,
It is known that the flatness cannot be maintained and the shape and dimensional accuracy of the resulting etching hole are deteriorated. Separately, as shown in FIG. 3, the electrode base material 1 is washed (a), then the resist 2 is applied to both surfaces of the base material 1 (b), and the glass mask 3 is applied to the resist 2 on both surfaces. After exposure using (c), the resist 2 is developed and patterned, and dried to form an etching film (d). Then, only one surface (back surface) side of the substrate 1 is etched to form a hole ( e) After that, an etching resistant backing material 4 is embedded in the hole (f), the surface (surface) opposite to the hole is etched again (g), and the resist 2 is peeled off (h). Two-step etching However, when this method is applied to a thin plate base material having a thickness of about 20 to 80 μm, a predetermined cross-sectional shape cannot be obtained.
Regarding the latter, for details, see JP-A-61-130492.
There is a description in the number etc.

[0004]

As described above, when the thickness of the base material is reduced to about 20 to 80 μm,
To form an etching hole having a width of 60 to 250 μm,
Since the plate thickness is relatively thin, in the two-step etching method shown in FIG. 3, the back surface side cannot be properly etched in order to obtain a desired cross-sectional shape (the etching hole penetrates before the desired cross-section is obtained. It was not practical. Further, in the above-described one-step etching method from both sides of the base material shown in FIG. 2, the base material is too thin to have sufficient strength, and the planarity during etching cannot be maintained, resulting in movement of the shape of the etching hole and straight line. The quality and dimensional accuracy were not satisfactory.

The present invention has been made in view of such a situation, and an object thereof is to obtain a steel sheet having a thickness of 20 to 80 μm.
In other words, it is an object of the present invention to provide a method of forming an etching hole having a size larger than its thickness while controlling its cross-sectional shape while maintaining good linearity and dimensional accuracy.

[0006]

A method of forming an etching through hole in a thin steel plate according to the present invention which achieves the above object, has a plate thickness of 20.
In a method of forming a through hole having a size larger than the plate thickness in a steel plate of ˜80 μm by etching, a resist layer is applied to both front and back surfaces of the steel plate, and the resist layer on the applied surface corresponds to the shape of the hole to be formed. One hole forming a relatively small size opening by patterning a relatively large size opening and forming at least two relatively small size openings in at least one cross section corresponding to the edge shape of the hole to be formed in the applied resist layer on the back surface. Patterning one or more to form a hole by etching through the resist layer on the back surface from the back surface to a depth that does not penetrate the steel plate, then burying an etching resistant backing material in the hole, and then A through hole is formed by etching a steel plate from the front surface through a resist layer on the front surface to form a hole communicating with the hole formed on the back surface. It is a method.

In this case, it is desirable that the size of the through hole to be formed is 3 to 5 times the plate thickness of the steel plate, and the depth of the hole etched from the back surface is 50 to 60% of the plate thickness of the steel plate.

According to this method, the plate thickness is 20 to 80 μm.
It is suitable to form a large number of through holes in a steel plate of m to form a shadow mask.

[0009]

According to the present invention, in the conventional two-step etching method, the resist layer applied to the back surface of the steel plate having a plate thickness of 20 to 80 μm is divided into two in at least one cross section corresponding to the edge shape of the hole to be formed. One or more relatively small-sized openings are patterned for each hole to be formed, and in the first-stage etching, etching is performed through the resist layer on the back surface to a depth that does not penetrate the steel plate from the back surface. Since the hole is formed, it is possible to form a through hole that is larger than the plate thickness of a thin steel plate while controlling the cross-sectional shape. The diameter of the etching hole can be adjusted by adjusting the distance between the openings. Furthermore, the etching time does not depend on the diameter of the holes provided, and large holes and small holes can be formed in substantially the same time.

The shape and dimensional accuracy of the etching hole are
Even a thin steel plate having a plate thickness of 20 to 80 μm can be made to the same degree as in the case of the conventional two-step etching method.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the steps of one embodiment in which the method for forming a through-hole for etching a thin steel plate according to the present invention is applied to a method for manufacturing a shadow mask.
The electrode substrate 1 made of, for example, LC (Low Carbon) material having a thickness of 80 μm is used to wash the substrate 1 as shown in FIG. Next, as shown in FIG. 2B, resists 21 and 22 are applied to both surfaces of the base material 1. Then, as shown in FIG. 3C, the resist patterns 21 and 22 on both surfaces are exposed with an electrode pattern using the glass masks 31 and 31. On this occasion,
As in the case of the conventional two-step etching method, the front pattern plate 31 has one light-shielding portion 311 having a size corresponding to the diameter of the concave hole to be etched on the surface of the base material 1 for each hole. However, the back pattern plate 32 has a base material 1 when viewed in cross section.
Two small-sized light-shielding portions 321 and 322 are provided at the portion corresponding to the edge of the hole opened from the back surface of the. Therefore, when the holes formed in the base material 1 are circular holes, the back pattern plate 3
The light-shielding portions 321 and 322 provided in 2 have a ring shape corresponding to the shape around the circular hole when seen in a plan view. The parts 321 and 322 are two thin lines located in parallel to the positions corresponding to both ends of the slot or slit hole.

After the front pattern plate 31 and the back pattern plate 32 are exposed and baked, the resists 21 and 22 are developed and patterned, and when dried, as shown in FIG. Openings 211 corresponding to the light shielding portions 311 of the plate 31 are formed, and openings 221 and 222 corresponding to the light shielding portions 321 and 322 of the back pattern plate 32 are formed in the resist 22 on the back surface.

Then, first, using the resist 22 on the back surface as an etching film, as shown in FIG. 1E, only the back surface side of the substrate 1 is etched to correspond to the portions corresponding to the openings 221 and 222. The shape, that is, if the hole to be formed in the base material 1 is a circular hole, a ring groove-shaped concave hole, and if the hole to be formed in the base material 1 is a slot or slit hole, positions corresponding to both ends of the slot or slit hole Two straight groove-shaped recesses are formed parallel to each other. In order to maintain the dimensional accuracy of the through hole by etching and the cross-sectional shape at a practical level, the depth of the recessed hole from the back surface is 5 times the thickness of the substrate 1.
About 0 to 60% is preferable.

Thereafter, as shown in FIG. 1 (f), an etching resistant backing material 4 is embedded in the hole, and the surface opposite to the hole is etched again through the opening 211 of the resist 21. A recessed hole as shown in g) is formed to form a through hole having a desired shape.

Finally, as shown in FIG. 1 (h), the backing material 4 and the resists 21 and 22 are peeled off, and a hole (3 to 5 times) larger than the thickness of the base material 1 is cross-sectioned. It is possible to obtain a shadow mask that is qualitatively satisfactory in terms of shape, linearity, and dimensional accuracy.

By the way, the diameter of the etching hole is equal to that of the opening 22.
It can be adjusted by adjusting the distance between 1, 222.
Further, as is clear from the above-mentioned opening process, the etching time does not depend on the diameter of the provided hole, and a large hole and a small hole can be formed in substantially the same time.

It should be noted that another one or more openings may be provided between the openings 221 and 222 so that no etching residue is generated in the etching holes, especially when the slots or slit-like holes are formed. .

[0018]

As described above, according to the method for forming through-holes in a thin steel plate of the present invention, in the conventional two-step etching method, the resist layer applied to the back surface of the steel plate having a plate thickness of 20 to 80 μm, One or more relatively small-sized openings in at least one cross section corresponding to the edge shape of the hole to be formed are patterned for each hole to be formed, and the resist on the back surface is etched in the first etching. Since the holes are formed by etching through the layers from the back surface to a depth that does not penetrate the steel plate, it is possible to form a large through hole while controlling the cross-sectional shape as compared with the plate thickness of the thin steel plate. The diameter of the etching hole can be adjusted by adjusting the distance between the openings. Furthermore, the etching time does not depend on the diameter of the holes provided, and large holes and small holes can be formed in substantially the same time.

The shape and dimensional accuracy of the etching hole are
Even a thin steel plate having a plate thickness of 20 to 80 μm can be made to the same degree as in the case of the conventional two-step etching method.

The etching through-hole forming method of the present invention is suitable for a method of manufacturing a thin shadow mask with high accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a process of one embodiment when the method of forming an etching through hole of a thin steel plate of the present invention is applied to a method of manufacturing a shadow mask.

2 is a view similar to FIG. 1 for a conventional double-sided one-step etching method.

FIG. 3 is a view similar to FIG. 1 for a conventional double-sided two-step etching method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thin steel plate 21, 22 ... Resist 211, 221, 222 ... Opening of resist 31 ... Front pattern plate 311 ... Light shielding part 32 ... Back pattern plate 321, 322 ... Light shielding part 4 ... Backing material

Claims (3)

[Claims] 1. A method for forming a through hole having a size larger than the plate thickness on a steel plate having a plate thickness of 20 to 80 μm by etching, wherein a resist layer is applied on both front and back surfaces of the steel plate, and the resist layer on the applied surface is coated with a resist layer. A relatively large-sized opening corresponding to the shape of the hole to be formed is patterned, and the resist layer on the applied back surface has a relatively small size of two in at least one cross section corresponding to the edge shape of the hole to be formed. One or more openings are patterned for each hole to be formed, and etching is performed through the resist layer on the back surface to a depth that does not penetrate the steel plate from the back surface to form a hole, and then the etching resistance is applied to the hole. Through hole is formed by embedding a backing material of the above, and then etching the steel plate from the front surface through the resist layer on the front surface to form a hole communicating with the hole formed on the back surface. Etching through hole forming method of thin steel plate, which comprises. 2. The size of the through hole to be formed is 3 of the plate thickness of the steel plate.
It is about 5 times, and the depth of the hole etched from the back surface is 50 to 60% of the plate thickness of the steel plate.
A method for forming an etching through hole in a thin steel plate as described above. 3. The method for forming an etching through hole in a thin steel plate according to claim 1, wherein the shadow mask is formed by forming a large number of through holes in a steel plate having a plate thickness of 20 to 80 μm.