JP2972490B2 - Method for hardening water-soluble photoresist - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, in a series of steps of manufacturing a shadow mask for a color CRT by a photo-etching method, hardening the water-soluble photoresist after development which is deposited on the surface of the shadow mask material How to process.

[0002]

2. Description of the Related Art A series of steps in a photo-etching method will be described by taking a case of manufacturing a shadow mask as an example.

[0003] Shadow masks are generally manufactured in large quantities and continuously. A shadow mask material is sent from a steel plate manufacturer to a shadow mask manufacturer in the form of a coil weighing 1 to 2 tons. In general, various treatments are applied to the shadow mask material fed from the coil while maintaining a long strip shape, and after a series of steps of photoetching, the long strip is cut into a single sheet form.

[0004] First, it has a long strip shape, and the plate thickness is 0.05 to
36% of 0.3mm low carbon aluminum killed steel and nickel
The contained shadow mask material such as an Invar type alloy is degreased to remove the rust-preventive oil on the surface, washed with water, subjected to surface conditioning using an acidic solution or an alkaline solution, and then washed with water (surface conditioning step). Next, a photosensitive solution, for example, a photosensitive solution composed of casein and dichromate is applied to both the front and back surfaces of the shadow mask material , and then dried, and a photoresist having a thickness of several μm is applied to each of the front and back surfaces of the shadow mask material. A film is formed (coating step). Next, on the surface of each photoresist film deposited on both the front and back surfaces of the shadow mask material,
Each master pattern having a required image corresponding to the electron beam passage hole to be formed is brought into close contact with the image position on the front side and the back side so as to be in close contact, and exposure is performed (printing step). Subsequently, the photoresist film is developed using warm water or the like, and the shadow mask material is immersed in a hardening solution, for example, a chromic anhydride solution, followed by a burning process using hot air at a temperature of 220 to 280 ° C. or an infrared heater. By performing (heating treatment), a resist film having a required pattern image is formed on each of both main surfaces of the shadow mask material (developing step). Using a ferric chloride aqueous solution, spray etching is performed on both principal surfaces of the shadow mask material to form a large number of through holes, and then the resist films are peeled off from both surfaces of the shadow mask material (etching step). Finally, the shadow mask material is cut to obtain a single-wafer shaped shadow mask (shearing step).

[0005] In the above-described series of photo-etching steps, after the development processing, the shadow mask material is immersed in a hardening solution, and then the burning processing is performed to harden unreacted casein and to improve the corrosion resistance of the resist film during etching. It is to improve. As a method of this hardening treatment,
For example, JP-A-57-148859 discloses that after a development process, a chromic anhydride solution or a dichromate solution is applied to the surface of a photoresist film by dip or spray, washed with water, replaced with alcohol, and dried. After that, a method of performing a burning process is disclosed. Also,
In Japanese Patent Publication No. 3-62264, the exposed water-soluble photoresist is washed with water, developed, then drained with a squeezing roller or an air knife, and then dipped in a chromic anhydride aqueous solution, Before and after this immersion, a chromic anhydride aqueous solution was sprayed on the water-soluble photoresist by a spray method or a shower method, and then the water-soluble photoresist was washed with water,
A method is disclosed in which after washing, water is removed by a squeezing roll, moisture is removed by a hot-air type air knife, and then burning of a water-soluble photoresist is performed. In these methods, hexavalent chromium of chromic anhydride or dichromate is reduced to trivalent chromium by burning, and a cross-linking reaction by binding of the reduced trivalent chromium and casein causes water-soluble photoreaction. The resist is cured.

[0006]

In recent years, color CRTs have been required to have a large screen, high luminance and high definition. The shadow mask used in such a color CRT tends to have a large thickness in order to prevent the image from fluctuating due to thermal expansion and vibration during use of the CRT. When the thickness of the shadow mask is increased, the time required for etching the shadow mask material in manufacturing the shadow mask increases. Here, in the manufacture of the shadow mask, a photosensitive solution composed of casein and dichromate is generally used. However, when the etching time of the shadow mask material is prolonged, the photosensitive mask is used to coat the surface of the shadow mask material. There is a problem that the deposited resist film cannot withstand long-time etching. That is, as shown in a partially enlarged sectional view of FIG. 3, a part of the resist film 2 is etched while the shadow mask material 1 on which the resist films 2 and 3 of a required pattern image are applied on both main surfaces is etched. When the etching is continued as it is, the shadow mask material 1 in the portion where the notch 4 is generated is excessively etched, and a through hole 5 larger than a normal through hole indicated by a two-dot chain line is formed. This causes a problem that the shadow mask becomes defective.

The cause of the chipping of the resist film is considered to be that the resist becomes too hard due to the thermal denaturation of casein during burning, and the resist film becomes rather brittle. Therefore, as a countermeasure, it is conceivable to lower the burning temperature to prevent the thermal denaturation of casein from occurring, thereby reducing the occurrence of chipping of the resist film. However, when the burning temperature is lowered, the chromium of the dichromate is not completely reduced from hexavalent to trivalent during burning,
Insufficient crosslinking of chromium with casein. As a result,
New problems such as the resist film dissolving in the etchant during etching, and the poor adhesion between the resist film and the shadow mask material, resulting in larger holes formed in the shadow mask material due to etching. Will occur.

In this case, even if the burning temperature is lowered, it is possible to completely reduce hexavalent chromium to trivalent chromium by extending the burning time. However,
For example, in the case of performing burning with hot air, a reduction treatment to trivalent chromium can be performed by performing a burning treatment at a temperature of 240 ° C. for 2 minutes. If it is performed, the processing takes more than 10 minutes. As described above, the method of lowering the burning temperature significantly reduces productivity, and cannot be practically adopted.

The present invention has been made in view of the above circumstances. Even if the etching time is long, the resist film is not chipped during the etching, and the burning time is long. It is an object of the present invention to provide a method for hardening a water-soluble photoresist, which can form a resist film having good etching resistance and good adhesion to a shadow mask material without performing the method.

[0010]

Means for Solving the Problems] The present invention, Shah water-soluble photoresist film having been subjected to the developing treatment on the surface is deposited
Dough mask material immersed in hardening solution or shadow mask
After spraying or dripping the hardening liquid on the material ,
Washed with water, then squeeze roller, a film, drained using such squeegee or air knife rubber plate or the like, water-soluble
After removing the moisture adhering to the surface of the photoresist film ,
Using hot air or infrared heater or induction heating
In hardening processing method of the water-soluble photoresist to allow subjected to a heat treatment to a shadow mask material, Shadouma
After draining the mask material and before subjecting the shadow mask material to heat treatment , a water-soluble photo
The resist film is irradiated with ultraviolet rays. In this case, water may be supplied to the water- soluble photoresist film during the irradiation of the water-soluble photoresist film with ultraviolet rays.

[0011]

According to the hardening method of the present invention, the shadow
Sha After the Umasuku material was washed with water and drained for example by spraying a hardening liquid is immersed or shadow mask material <br/> in hardener
Before heating the dough mask material, place it on the shadow mask material.
UV rays are irradiated on the water-soluble photoresist film of
When, for example, an aqueous solution of chromic anhydride is used as the hardening solution, the reaction of reducing hexavalent chromium of chromic anhydride permeated into the water-soluble photoresist film to trivalent chromium is promoted by ultraviolet rays. At this time, water impregnated with chromic anhydride
The sensitivity of a soluble photoresist film to ultraviolet light is
Tends to decrease as the water content of the photoresist film decreases
However, before heating the shadow mask material,
UV light is applied to the photoresist film containing
Therefore, the utilization efficiency of the ultraviolet rays is increased. Also shadow
After washing the mask material with water, drain it and use the water-soluble photoresist
After removing the moisture adhering to the surface of the membrane,
Since the photoresist film is irradiated with ultraviolet rays,
Moisture distribution in photoresist film during UV irradiation
And uniform hardening treatment
Can be. Therefore , hexavalent chromium is sufficiently reduced to trivalent chromium even if burning is performed at such a low temperature that does not cause chipping of the resist film during etching and without increasing the processing time. As a result, a resist film having good etching resistance and adhesion to the shadow mask material is formed.

Further , a water-soluble photoresist on a shadow mask is used.
The water-soluble photoresist
When to supply water to the resist film, the ultraviolet
Since the utilization efficiency is higher , the reduction of hexavalent chromium to trivalent chromium is further promoted, and a better resist film is formed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

FIG. 1 shows an example in which the present invention is applied to a manufacturing process of a shadow mask, and is a schematic view showing an example of a configuration of a developing / hardening apparatus for performing a hardening method according to the present invention. FIG. The apparatus includes a supply unit 10 for a long strip-shaped shadow mask material (substrate), an accumulator 12, a development processing unit 14, a hardening liquid supply unit 16, a washing unit 18, a draining unit 20, an ultraviolet irradiation unit 22, a burning processing unit. 24, and a winding section 26 of a shadow mask material.

In the supply portion 10 of the shadow mask material, a substrate having a surface coated with a baked water-soluble photoresist film is held in the form of a coil 28, and the substrate 30 is continuously fed from the coil 28. It is supposed to be. The substrate 30 fed out from the shadow mask material supply unit 10 is adjusted by the accumulator 12 so that the transfer timing is adjusted and the tension is kept constant. The development processing section 14 is provided with a development tank 32, and the substrate 30 is introduced into the development tank 32, and the substrate 30 is
While passing through the inside 32, hot water, for example, 40 ° C. hot water, is sprayed on the two main surfaces of the substrate 30 from the plurality of spray nozzles 34 arranged on both sides along the transport path of the substrate 30,
It is developed. The hardening solution supply section 16 is provided with a hardening solution tank 36 containing a hardening solution, for example, a chromic anhydride solution 38, and the hardening solution tank 36 in the hardening solution tank 38 in the hardening solution tank 36 is provided. The substrate 30 is immersed. Further, a pair of shower nozzles 40 are disposed above the hardening solution tank 36 on both sides of the transport path of the substrate 30, and the substrate is introduced into an aqueous solution of chromic anhydride 38 in the hardening solution tank 36. Prior to immersing the substrate 30, a chromic anhydride aqueous solution is sprayed onto both main surfaces of the substrate 30 from a pair of shower nozzles 40. As a means for supplying the hardening liquid to the substrate, in the illustrated example, the dipping method and the hanging coating method from the shower nozzle are used in combination, but the hardening liquid is applied to the substrate by only one of the methods. May be supplied, or
A spray method may be used.

The washing section 18 is provided with a washing tank 42, and a plurality of spray nozzles 44 are arranged in both sides of the washing tank 42 along the transport path of the substrate 30. Then, the substrate 30 is heated from a plurality of spray nozzles 44 to both main surfaces while passing through the washing tank 42 with hot water, for example, 40 ° C.
Is washed by being sprayed with hot water. A pair of squeezing rollers 46 and a pair of air knives 48 are sequentially provided in the outlet direction of the washing tank 42 in the transport direction, and the draining unit 20 drains the substrate 30 after washing. As a means for draining, a method of squeegeeing the surface of the substrate with a film or a rubber plate may be adopted.

A plurality of ultraviolet irradiation lamps, for example, a 6.4 kW mercury lamp 50 are arranged in a row on both sides of the ultraviolet irradiation section 22 along the transport path of the substrate 30. Also,
The burning processing section 24 is configured by arranging a number of infrared heaters 54 on both sides of the burning chamber 52 along the transport path of the substrate 30. Then, while the substrate 30 passes through the burning chamber 52, the substrate 30 is heated to about 200 ° C. Note that hot air may be used to heat the substrate, or an induction heating method may be used . Ba Ningu processor board 3 having been subjected to the burning treatment by hardening treatment with 24
Numeral 0 is wound in the form of a coil 58 by the shadow mask material winding section 26 via a driving roller 56. Reference numeral 60 in the drawing denotes a substrate transport roller.

Using the developing / hardening apparatus having the above-described structure, the substrate 30 having the baked water-soluble photoresist film adhered to both main surfaces thereof is subjected to the developing section 14 and the hardening solution supply section.
16, the washing section 18, the draining section 20, the ultraviolet irradiation section 22, and by performing processing while sequentially transporting to the burning processing section 24,
The water-soluble photoresist film adhered to both main surfaces of the substrate 30 is developed and hardened to obtain a substrate in which a resist film having a required pattern image is formed on both main surfaces. In this method, after the development treatment, the aqueous solution of chromic anhydride 38
After the substrate 30 immersed in and washed with water is drained, the substrate 30
Is irradiated with ultraviolet rays, and then heat treatment is performed. Therefore, the reduction reaction of chromic anhydride that has penetrated into the water-soluble photoresist film on the surface of the substrate 30 from hexavalent chromium to trivalent chromium is performed. The substrate is treated at a low temperature of about 200 ° C.
Even if 30 is heat-treated, hexavalent chromium is sufficiently reduced to trivalent chromium, and a resist film excellent in etching resistance and adhesion to a substrate can be obtained.

Incidentally, the sensitivity of a water-soluble photoresist film impregnated with chromic anhydride to ultraviolet light tends to decrease as the water content of the photoresist film decreases. Therefore, as in the utilization efficiency of ultraviolet rays becomes high, you like to ultraviolet radiation to the substrate 30 at the stage before loading the substrate 30 into the washing and the burning chamber 52 after the draining. Further, when the draining is not performed after the water washing, the distribution of moisture in the photoresist film is not uniform during the irradiation of the substrate with ultraviolet light and the burning process, so that a uniform hardening process cannot be performed, and the subsequent etching is performed. Uneven etching tends to occur during processing. Therefore, it is necessary to drain the water with the squeezing roller 46 and the air knife 48 before irradiating the substrate with ultraviolet light after washing. By irradiating the substrate with ultraviolet rays, a reaction in which hexavalent chromium in the photoresist film is reduced to trivalent chromium proceeds, but when the substrate is not subjected to heat treatment, the resist film is in a soft state. As a result, the resist film is likely to bend during the etching process, and the resist film is easily cracked or chipped. Therefore, it is necessary to heat the substrate.

FIG. 2 is a schematic view showing another example of the configuration of a developing / hardening apparatus for performing the hardening method according to the present invention. In FIG. 2, components denoted by the same reference numerals as those used in FIG. 1 are the same elements and members having the same functions as those described with reference to FIG. 1, and description thereof will be omitted.

In this apparatus, a hot water supply section 62 and a second drain section 64 are provided between the ultraviolet irradiation section 22 and the burning section 24.
A second ultraviolet irradiation section 66 is provided in order in the transport direction of the substrate 30. The hot water supply unit 62 has hot water, for example, 40
A hot water tank 68 containing hot water 70 ° C. (although room temperature water may be used, but hot water is preferable because water permeability to the photoresist film is good and processing time can be shortened) is provided. By immersing the substrate 30 in hot water 70 in the hot water tank 68, water is supplied to the photoresist film. Instead of immersing the substrate 30 in the hot water 70, water may be supplied to the substrate by a spray method, a shower method, or the like. Second drainer 64
Is composed of a pair of squeezing rollers 72 and a pair of air knives 74 arranged sequentially in the transport direction. Also, the second
A plurality of ultraviolet irradiation lamps, for example, a 6.4 kW mercury lamp 76, are arranged on both sides of the ultraviolet irradiation section 66 along the transfer path of the substrate 30.

Developing using the apparatus having the configuration shown in FIG.
When the hardening process is performed, moisture is supplied to the photoresist film during the irradiation of the substrate 30 with ultraviolet rays, so that hexavalent chromium of chromic anhydride that has penetrated into the photoresist film becomes trivalent. The reaction of reduction to chromium will be further accelerated. As a result, a better resist film is formed on the substrate surface.

As the water-soluble photoresist, besides milk casein, natural polymers such as fish glue, gelatin and egg white, or synthetic polymers such as PVA (polyvinyl alcohol) and polyacrylamide, dichromate, Those containing a diazonium salt, an azide compound or the like as a sensitizer are generally used, but for the purpose of improving the etching resistance of these water-soluble photoresists and the adhesion to the substrate, the photosensitivity after development processing is increased. Diazonium salts such as chromic anhydride or dichromate, or tetrazonium salts, polydiazonium salts, para-formaldehyde condensates of p-diazophenylamine, and 4,4′-diazidostilbene-2,2′-
The hardening treatment may be performed using a solution of a water-soluble bis azide compound such as sodium disulfonate. These cases are also the same in that the photocrosslinking or coordination bond of the hardener and the thermosetting of the polymer compound are used, and the present invention can be similarly applied.

[0024]

Since the present invention is constructed and operates as described above, when the hardening treatment of a water-soluble photoresist is performed by the method according to the present invention, even if the etching time becomes long, The etching resistance and the shadow are prevented without causing the chipping of the resist film during the etching and without increasing the burning time.
It is possible to form the adhesion of excellent resist film with Umasuku material, Therefore, with good shadow mask proper hole is formed is obtained, it is possible to maintain productivity is high.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a case where the present invention is applied to a manufacturing process of a shadow mask, and showing an example of a configuration of a developing / hardening apparatus for performing a hardening method according to the present invention. .

FIG. 2 is a schematic diagram illustrating the development and hardening of the hardening method according to the present invention.
It is a schematic diagram which shows another example of a structure of the hardening processing apparatus.

FIG. 3 is a diagram for explaining a problem in a conventional hardening treatment method, and is a partially enlarged cross-sectional view of a shadow mask material.

[Explanation of symbols]

 14 Development processing part 16 Hardening liquid supply part 18 Rinse part 20, 64 Drain part 22, 66 UV irradiation part 24 Burning processing part 30 Substrate 32 Development tank 34 Spray nozzle 36 Hardening liquid tank 38 Hardening liquid (chromic anhydride aqueous solution) ) 40 Shower nozzle 42 Rinse tank 44 Spray nozzle 46, 72 Squeeze roller 48, 74 Air knife 50, 76 UV irradiation lamp (mercury lamp) 52 Burning chamber 54 Infrared heater 62 Hot water supply section 68 Hot water tank 70 Hot water

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-69613 (JP, A) JP-A-4-27113 (JP, A) JP-A-63-237418 (JP, A) JP-A-59-1984 57432 (JP, A) JP 3-62264 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03F 7/40

Claims (2)

(57) [Claims] 1. After immersing a shadow mask material on which a water-soluble photoresist film having undergone a developing treatment is applied on a surface thereof into a hardening solution or spraying or dripping the hardening solution onto the shadow mask material , , washed with water, then drained to water
After removal of water adhering to the surface of the soluble photoresist film, the film hardening process of the water-soluble photoresist to allow subjected to a heat treatment to a shadow mask material, the shadow mass even after having drained the shadow mask material
Before subjected to heat treatment to click material, water containing water
A method for hardening a water- soluble photoresist film , comprising irradiating the soluble photoresist film with ultraviolet rays. 2. The method according to claim 1, wherein water is supplied to the water- soluble photoresist film during the irradiation of the water-soluble photoresist film with ultraviolet rays.