JP2003100210A - Manufacturing method of shadow mask and manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a shadow mask of fine quality with an accurate through-hole size (without deficiency in transmittance), where a material is used effectively. SOLUTION: A first etching is performed by steps of measuring the size of an opening region of a resist pattern for a small hole (1), calculating an adequate spray pressure (theoretical value of spray pressure) to carry out etching based on a target hole anticipated from the size of the opening region, conditions of an etching solution, etching time and a spray pressure, and controlling the spray pressure (operating value of the spray pressure) by feed- forwarding the calculated value. The size of the hole is compared with the size of the target hole and the spray pressure (operating value of the spray pressure) is controlled by feeding back the corrected pressure value corresponding to the measured size difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a shadow mask by using a photo-etching method and carrying out two-step etching of one side of a thin metal plate, the first etching on the other side, and the second etching on the other side. The present invention relates to a manufacturing method and a manufacturing apparatus of a high-definition shead mask used for a monitor of high quality.

[0002]

2. Description of the Related Art A color picture tube has a shadow mask, which faces a fluorescent surface formed inside a display portion of a glass tube, and inside which a large number of through holes are regularly arranged in a thin metal plate. This shed mask is also used for fluorescent screen formation,
Further, it is installed so that the electron beam emitted from the electron gun is correctly incident on the phosphor screen.

Conventionally, the manufacture of a high-definition shead mask is
After degreasing, surface conditioning, and cleaning both sides of a low carbon steel thin sheet with a thickness of about 0.10 mm, apply a water-soluble photosensitive solution consisting of casein or polyvinyl alcohol and ammonium dichromate to both sides and dry it to form a photoresist. Form a film. Then, it is exposed and baked through an exposure mask having a predetermined pattern and developed to form a resist pattern having open areas on both sides of the thin metal plate. After a while,
Hardening treatment and burning treatment are applied to this resist pattern, and the first etching is performed only on the first surface.

A ferric chloride solution is used as an etching solution, and spray etching is usually performed. It is important to stop the progress of the etching of the first surface in the middle so that it does not penetrate. Next, after washing and drying the thin metal plate with water, the first etching surface is coated and cured with, for example, a heat-softening resin or a photo-curing resin, and the concave portion formed on the first surface by the first etching is completely removed. A corrosion-resistant film is formed to fill the entire surface. The first surface may be the small hole side or the large hole side, but in most cases, it is the small hole side.
Subsequently, second etching is performed on the back surface of the first surface to form through holes. Finally, the corrosion resistant film and the resist pattern are stripped off and unnecessary portions are cut off to obtain a shadow mask.

The through hole of the above described shed mask plays a role of correctly guiding the electron beam to the fluorescent screen when the shed mask is incorporated in the color picture tube. Therefore, the shape of each through hole formed in the shear mask, especially the hole diameter of the through portion,
The hole diameter is set in advance in the design stage before the manufacture of the shadow mask, and the hole diameter is designed so that the color cathode ray tube can exhibit the desired performance when the shadow mask is incorporated in the color cathode ray tube.

In a color picture tube used for reproducing a color broadcast, the through hole of the shadow mask is larger than the thickness of the thin metal plate and can be easily etched. However, as a shadow mask used for a display or the like that requires a higher resolution, for a high-definition shadow mask whose through holes are smaller than the plate thickness dimension of the metal thin plate, due to the side etching that occurs inevitably, the above method is used. Its manufacture is extremely difficult.

That is, the reason why the diameter of the through hole is not desired is, for example, a slight change in the photoresist film thickness in the step of forming the photoresist film. When the photoresist film thickness changes subtly, the size of the opening area of the resist pattern changes, so the etched hole diameter also changes, and the desired hole diameter cannot be obtained.
Further, in the etching process, for example, the conditions of the etching liquid supplied to the etching chamber, that is, the conditions such as the temperature of the etching liquid, the density, and the fatigue may deviate from the preferable conditions. If the etching liquid conditions deviate from the preferable conditions, the desired hole diameter cannot be obtained, and as a result, the through hole diameter becomes out of the standard, and even if it is within the standard, there is a problem that it varies.

For this reason, in the production of a high-definition sheer dough mask, the through-hole diameter is inspected after the two-step etching is performed to form the through-hole. When a defect is found in the through hole diameter as a result of the inspection, the manufacturing condition, for example, the etching condition is changed to a suitable condition in order to obtain the desired through hole diameter, and the shadow mask having the desired through hole diameter is obtained. .

As a method of inspecting the through hole diameter, there is a method of evaluating the through hole diameter by using the transmittance. This method
A single-wavelength light emitted from a light source is passed through a lens to form a single-wavelength parallel light, which is applied to an inspection site of a shadow mask. The light passing through the through-hole of the shear mask is received by a light receiver such as a photomultiplier tube. Next, the electrical signal received by this light receiver is used to judge whether the diameter of the through hole is desired by the electronic computer. Further, in the conventional method for manufacturing a sheer mask, if the resist pattern and the corrosion-resistant film are still formed on the surface of the sheer mask, the transmitted light from the light source is blocked or scattered, so that the transmittance can be measured. An error occurs, and the inspection based on the above transmittance cannot be performed accurately. Therefore, it is necessary to remove the resist pattern and the corrosion resistant film in order to perform the inspection based on the transmittance.

Usually, the thin metal film, which is the material for the sheer mask, is in the form of a long strip and is wound into a roll, and is unwound from the roll to continuously manufacture the sheer mask. As described above, in the conventional method for manufacturing a shear mask, the through hole diameter (transmittance) cannot be measured immediately after etching, and the through hole diameter (transmittance) is inspected after the film peeling step. Therefore, there is a problem that a one-tempo shift occurs in checking whether or not it is within the standard.

In the conventional manufacturing method, the diameter of the through hole (transmittance) was measured after the film was peeled off, and when it did not meet the standard, the spray pressure was changed to deal with it. For example, the size of the open area of the resist pattern may change, the etching solution conditions may change, and the through-hole diameter may change (transmittance change).
If the product is out of the standard due to the occurrence of the above, the products from the portion where the transmittance of the through-hole diameter is inspected to the portion where the spray pressure is changed have a defective through-hole diameter and are wasted materials.

In particular, a blind-shaped sheer dough mask (aperture grille) has a blind-shaped shadow mask which is not stretched and loosened until it is cut into single-leaf sheets, and therefore the transmittance cannot be inspected. Since it takes a lot of time to inspect the product, it is not possible to recognize even if a product having a defective through-hole diameter is manufactured, and there is a problem that a large number of defective products having a through-hole diameter are manufactured. As described above, in the continuously manufactured shear mask, once the through-hole dimension defect occurs, it takes time until the inspection and the etching condition change, which causes a large number of through-hole dimension defects.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a large number of through holes are formed in a long strip-shaped metal thin plate by two-step etching using a photoetching method. An object of the present invention is to provide a shadow mask manufacturing method and a manufacturing apparatus in which a dimensional defect (transmissivity defect) of a through hole diameter is eliminated when a shear mask is manufactured, a high-quality shadow mask is obtained, and a material is not wasted. To do.

[0014]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing a shadow mask in which a large number of through holes are formed by performing first etching on one surface and second etching on the other surface of a long thin metal sheet using a photoetching method. In 1), after forming the resist pattern for small holes, the dimension of the opening region of the resist pattern for small holes is measured at any time, and 2) The dimension of the opening region of the resist pattern for small holes measured at any time and the measurement at any time. The small hole diameter after the first etching, which is predicted from the etching liquid conditions, etching time, and spray pressure, is adjusted so that the target small hole diameter (small hole diameter set value) is etched to an appropriate spray pressure (spray pressure). (Theoretical value) is calculated, and the calculated proper spray pressure (spray pressure theoretical value) is feed-forwarded to control the spray pressure (spray pressure operation value) at any time. It is a manufacturing method of a shadow mask, characterized by the formation of pores by performing the quenching.

The present invention also provides, in the method for manufacturing a shadow mask according to the above-mentioned invention, 1) immediately after the first etching, the resist pattern for small holes is stripped off, and the size of the small holes is measured at any time, and 2) at any time. The measured small hole diameter is compared with the target small hole diameter (small hole diameter setting value), and the spray pressure correction amount corresponding to the difference is fed back to correct the proper spray pressure (spray pressure theoretical value). Is added to control the spray pressure (spray pressure operation value) at any time, and the first etching is performed to form small holes.

Further, the present invention relates to an apparatus for manufacturing a shadow mask in which a large number of through holes are formed by performing first etching on one surface and second etching on the other surface of a long strip-shaped thin metal plate by using a photoetching method, 1). Means for measuring the size of the open area of the small hole resist pattern as needed after the small hole resist pattern is formed, 2) The size of the open area of the small hole resist pattern measured at any time, and the size of the small hole resist pattern is measured at any time. Appropriate spray pressure (spray pressure theoretical value) so that the small hole diameter after the first etching, which is predicted from the etching liquid conditions, etching time, and spray pressure, will be etched to the target small hole diameter (small hole diameter set value). And means for controlling the spray pressure (spray pressure operation value) at any time by feed-forwarding the calculated proper spray pressure (spray pressure theoretical value). An apparatus for manufacturing a shadow mask, characterized by comprising linked to the etching process.

Further, the present invention provides the shadow mask manufacturing apparatus according to the above invention, wherein 1) means for measuring the size of the small pores at any time after the film removal step immediately after the first etching step, and 2) small measured at any time. The size of the hole diameter is compared with the target small hole diameter (small hole diameter set value), and the spray pressure correction amount corresponding to the difference is fed back to correct the appropriate spray pressure (spray pressure theoretical value) to correct the spray pressure. 4. The shadow mask manufacturing apparatus according to claim 3, further comprising: a means for controlling the (spray pressure operation value) at any time, which is connected to the first etching step.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is a perspective view schematically showing a portion of a first etching step in an embodiment of the shadow mask manufacturing apparatus according to the present invention. As shown in FIG. 1, the portion of the first etching process is the etching chamber (1),
It is composed of an etching liquid tank (2), a pump (3), an etching liquid supply pipe (4), and a spray nozzle (5) in the etching chamber. The stripping chamber (6) is provided adjacent to the etching chamber (1).

The metal thin plate (7) on which the resist pattern for small holes is formed is conveyed from the left side to the right side of the magazine in the etching chamber (1) and the peeling chamber (6) as indicated by the arrow. Etched and stripped. The etching liquid reaches the spray nozzle (5) from the etching liquid tank (2) through the etching liquid supply pipe (4) by the pump (3), and is sprayed from the spray nozzle (5) to the metal thin plate (7) to remove the metal thin plate. It is adapted to be etched and circulated in the etching liquid tank (2). A protective film may be attached to the large hole side in order to prevent etching and film peeling on the large hole resist pattern formation surface side, but the illustration is omitted for convenience of description.

The high-speed camera (8) measures the size of the opening area of the resist pattern for small holes at any time after the resist pattern for small holes is formed, and is provided immediately before the etching chamber (1). The high-speed camera (9) measures the size of the small hole diameter at any time after the small hole resist pattern is removed immediately after the first etching, and is provided immediately after the film removing chamber (6). . FIG. 2 is an explanatory diagram of the first etching step in one embodiment of the method for manufacturing a shadow mask according to the present invention.

As a material for the sheer mask, for example, a long strip of low carbon steel thin metal plate having a thickness of about 0.1 mm is degreased and washed, and a photoresist having a predetermined thickness is applied on both surfaces thereof. Dry to form a photoresist film. Next, a large hole and a small hole exposure mask having a predetermined pattern are respectively adhered to both sides of the thin metal plate, exposed and baked from both sides, and developed to have large and small open areas on both sides of the thin metal plate. A resist pattern is formed. Next, washing with water and burning are performed to complete the formation of the resist pattern (FIG. 2A).

Next, as shown in FIGS. 1 and 2, a high-speed camera (8) inputs an image of the resist pattern on the small hole surface side to a computer, and the size of the open area of the resist pattern is processed by image processing. (FIG. 2B), the position of the roll and the size of the open area are stored in the recording medium. Next, just before the etching chamber (1), the side surface of the large hole that is not etched in the first etching step is measured. A low-adhesive film for etching protection containing polypropylene as a main component and having a film thickness of about 0.02 mm is attached to the above to prevent the large hole side from being etched (not shown).

In the first etching step ((FIG. 2C)), an etching solution of ferric chloride is used, and the etching solution conditions are, for example, an etching solution temperature of 65 ° C. and an etching solution density of 1.525 g / cm 3. , Redox potential 650
Set to mV. However, the diameter of the small holes formed in the first etching step may not be the desired size due to fluctuations in the etching solution conditions. The present invention is characterized in that an appropriate spray pressure is feed-forwarded in the first etching step to etch the small holes to a desired size.

That is, in the present invention, the moving average of the dimension of the open area of the resist pattern for small holes measured at any time, the temperature of the etching solution, the density of the etching solution, the redox potential of the etching solution, and the release of the solution, which are measured at any time. An appropriate spray pressure (spray pressure) is set so that the small hole diameter after the first etching, which is predicted from the etching solution conditions such as hydrochloric acid concentration, etching time, and spray pressure, is etched to the target small hole diameter (small hole diameter setting value). The theoretical spray pressure is calculated, and the calculated proper spray pressure (spray pressure theoretical value) is feed-forwarded to control the spray pressure (spray pressure operation value) at any time. Therefore, the obtained small hole diameter is close to the target small hole diameter (small hole diameter set value).

Further, in the present invention, the size of the small hole diameter is measured (FIG. 2 (E)) after the film peeling step (FIG. 2 (D)) immediately after the first etching step shown in FIG. It is characterized by feeding back pressure. The image of the small hole surface is input to the electronic computer with the high-speed camera (9), the size of the small hole diameter actually etched by image processing is measured, and the measured small hole size data is sent to the electronic computer to set the target small size. Perform comparative verification with the hole diameter (small hole diameter setting value). If the measured small hole size is larger than the target small hole size (small hole set value), reduce the spray pressure.
Conversely, if it is small, feedback control is performed by raising the spray pressure to match the target small hole diameter (small hole diameter setting value).

That is, in one embodiment shown in FIGS. 1 and 2, the predicted proper spray pressure (spray pressure theoretical value) is feed-forwarded to control the spray pressure (spray pressure operation value) at any time. In addition, the size of the small hole diameter after etching is measured, and the spray pressure correction amount is fed back to correct the spray pressure (spray pressure theoretical value) to control the spray pressure (spray pressure operation value) at any time. Is. Therefore, the obtained small hole diameter is extremely close to the target small hole diameter (small hole diameter set value).

Next, for example, an ultraviolet-curing acrylic resin is applied on the side surface of the small hole formed in the first etching step so that air bubbles do not enter, and the thickness is increased to 2 by irradiation with ultraviolet rays.
A protective layer of a corrosion resistant resin having a thickness of about 0 μm is formed. Alternatively, a heat-softening resin having a softening point of 90 ° C or higher is softened at 150 ° C or higher on the side surface of the small hole, coated in the same manner, and then returned to room temperature to be cured to form a protective layer of a corrosion-resistant resin. You may. Here, the etching protection film attached to the side surface of the large hole is peeled off so that the large hole surface is not etched and the resin applied to the small hole surface does not adhere to the large hole surface (not shown). No).

Next, in the second etching step, for example, the etching solution temperature is 60 ° C. and the etching solution density is 1.5.
A ferric chloride solution having a redox potential of 650 mV of 10 g / cm 3 is sprayed from both sides at a predetermined pressure for a predetermined time to form a large number of through holes. It has been found that a high degree of control is not required for etching the sides of large holes.
A portion of the side surface of the small hole that is etched into a small semi-circle and then a side surface of the large hole that is etched into a large semi-circle is joined to determine the diameter of the through hole and the transmittance. As shown in the process diagram of FIG. 3, the through hole (38) is close to the side surface of the small hole and is severely linked to the size of the small hole, and the diameter of the through hole is substantially determined by the size of the small hole. In other words, in the second etching process for forming the large holes, it is not necessary to control spray pressure with high precision as in the first etching process.

Even in the second etching step, it is necessary to thoroughly wash the etching surface with water so that the non-uniform etching does not proceed and to completely remove the etching solution. Finally, as a stripping solution for the resist film and the corrosion resistant film, for example, 60 ° C., 20
% Caustic soda aqueous solution is sprayed to dissolve and remove the resist pattern formed on the side surface of the large hole and the protective layer of the corrosion resistant resin, followed by washing with water and drying to obtain a shadow mask having a desired through hole diameter. Here, as the hole shape of the shear mask, there is no problem in manufacturing a perfect circle, an ellipse, a square, or a blind-shaped aperture grill.
In FIG. 3, (a) shows a state immediately before the first etching, (b) shows immediately after the first etching, (c) shows after the formation of the corrosion resistant film, (d) shows after the second etching, (E) shows each shed mask.

[0030]

According to the present invention, the size of the opening area of the resist pattern for small holes, the etching solution conditions, the etching time,
The proper spray pressure (spray pressure theoretical value) is calculated so that the small hole diameter predicted from the spray pressure and the target small hole diameter (small hole diameter setting value) are etched, and this appropriate spray pressure (spray pressure) is calculated. The theoretical value) is feed-forwarded to control the spray pressure (spray pressure operation value), and the first etching is performed to form small holes, so dimensional defects of the through-hole diameter (poor transmittance) are eliminated and quality is improved. A good shadow mask can be obtained, and a method of manufacturing a shadow mask without waste of materials can be obtained. Also, the size of the small hole diameter is compared with the target small hole diameter (small hole diameter setting value), and the spray pressure correction amount corresponding to the difference is fed back to correct the appropriate spray pressure (spray pressure theoretical value). Since the spray pressure (spray pressure operation value) is controlled and the first etching is performed, dimensional defects can be reduced more reliably.

Further, according to the present invention, 1) means for measuring the size of the open area of the resist pattern for small holes, 2) the size of the open area of the resist pattern for small holes, and etching solution conditions,
Calculate the proper spray pressure (spray pressure theoretical value) so that the small hole diameter after the first etching predicted from the etching time and spray pressure will be etched to the target small hole diameter (small hole diameter setting value), A means for controlling the spray pressure (spray pressure operation value) by feed-forwarding the calculated proper spray pressure (spray pressure theoretical value) is provided in connection with the first etching step. It becomes a shadow mask manufacturing apparatus that eliminates (transmission defect), obtains a high-quality shadow mask, and does not waste materials. Further, 1) means for measuring the size of the small hole diameter, 2) comparing the size of the small hole diameter with a target small hole diameter (small hole diameter setting value), and feeding back a spray pressure correction amount corresponding to the difference to obtain the appropriate value. Since a means for controlling the spray pressure (spray pressure operation value) by correcting the proper spray pressure (spray pressure theoretical value) is connected and provided in the first etching step, dimensional defects can be reduced more reliably. .

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a portion of a first etching step in an embodiment of a shadow mask manufacturing apparatus according to the present invention.

FIG. 2 is an explanatory diagram of a first etching step in an embodiment of the method for manufacturing a shadow mask according to the present invention.

3A to 3E are process diagrams in one embodiment.

[Explanation of symbols]

1 ... Etching chamber 2 ... Etching liquid tank 3 ... Pump 4 ... Etching liquid supply pipe 5 ... Spray nozzle 6 ... Stripping chamber 7: Metal thin plate having a resist pattern for small holes formed 8, 9 ... High-speed camera 31 ... Metal sheet 32: Small hole resist pattern 33 ... Resist pattern for large holes 34 ... Film 35 ... small hole 36 ... Corrosion resistant film 37 ... Large hole 38 ... through hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Iori Hashimoto             1-3 Rene, Takaya Tatehara-cho, Sakyo-ku, Kyoto             Shimogamo East No.405 (72) Inventor Shinji Hasebe             38-381 Oshima, Momoyama-cho, Fushimi-ku, Kyoto (72) Inventor Hidemoto Nakagawa             40-12-809 Denenchofuhonmachi, Ota-ku, Tokyo F term (reference) 4K057 WA11 WA19 WB01 WD05 WE08                       WG01 WG02 WG03 WG08 WJ01                       WJ05 WL03 WM04 WN03                 5C027 HH08 HH09 HH10 HH11 HH19                       HH29

Claims (4)

[Claims] 1. A method for producing a shear mask, wherein a large number of through holes are formed by performing first etching on one surface and second etching on the other surface of a long strip-shaped thin metal plate by using a photoetching method, and 1) a resist for small holes. After forming the pattern, the size of the open area of the resist pattern for small holes is measured at any time, and 2) the size of the open area of the resist pattern for small holes that is measured at any time, and the etching solution conditions and etching that are measured at any time. Calculate and calculate an appropriate spray pressure (spray pressure theoretical value) so that the small hole diameter after the first etching, which is predicted from the time and spray pressure, will be etched to the target small hole diameter (small hole diameter setting value) Feed forward the appropriate spray pressure (spray pressure theoretical value) to control the spray pressure (spray pressure operation value) at any time, and perform the first etching to form small holes. Method of manufacturing a shadow mask, characterized by. 2. A resist pattern for small holes is peeled off immediately after the first etching, and a size of the small hole diameter is measured at any time. 2) A small hole diameter whose target is the size of the small hole diameter measured at any time. (Small hole diameter set value), the spray pressure correction amount corresponding to the difference is fed back to correct the appropriate spray pressure (spray pressure theoretical value), and the spray pressure (spray pressure operation value) is controlled at any time. The method according to claim 1, wherein the first etching is performed to form the small holes. 3. A device for manufacturing a shadow mask, wherein a large number of through holes are formed by performing first etching on one surface and second etching on the other surface of a long strip-shaped thin metal plate by using a photoetching method, and 1) a resist for small holes. Means for measuring the size of the open area of the resist pattern for small holes at any time after the formation of the pattern, 2) the size of the open area of the resist pattern for small holes measured at any time, and the etching solution conditions measured at any time, Calculate the proper spray pressure (spray pressure theoretical value) so that the small hole diameter after the first etching predicted from the etching time and spray pressure will be etched to the target small hole diameter (small hole diameter setting value), The first etching step is a means for feeding forward the calculated proper spray pressure (theoretical spray pressure value) and controlling the spray pressure (spray pressure operation value) as needed. Apparatus for manufacturing a shadow mask, characterized by comprising connecting to. 4. A means for measuring the size of the small pores at any time after the film stripping step immediately after the first etching step, and 2) a small pore diameter for the purpose of setting the size of the small pores measured at any time. Value) and feed back a spray pressure correction amount corresponding to the difference to correct the appropriate spray pressure (spray pressure theoretical value) to control the spray pressure (spray pressure operation value) at any time. The shadow mask manufacturing apparatus according to claim 3, wherein the shadow mask manufacturing apparatus is provided by being connected to one etching process.