JP2008051920A - Method for producing screen plate for screen printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a screen plate for screen printing by which a large screen plate such as a plate for a PDP (Plasma Display Panel) can inexpensively be obtained by using a photomask that is prepared by electroless plating on a glass substrate and that has preferable adhesiveness between the plated metal layer and the substrate of the photomask. <P>SOLUTION: A glass substrate is subjected to electroless plating to form a metal film, on which a photoresist film is formed, exposed along a pattern, developed to form an image and etched to form the pattern. The obtained pattern is used as a photomask to manufacture a screen plate for screen printing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for manufacturing a screen printing screen plate capable of large-scale printing. For example, a method for manufacturing a screen printing screen plate capable of printing a panel requiring a large size such as a plasma display panel (PDP). About.

  As a display panel, a flat panel display is being actively researched and developed by each research institution as an alternative to a CRT display. Among flat panel displays, PDPs are easy to increase in size compared to other flat panel displays, and therefore, in recent years, the increase in size has been promoted.

  In general, a PDP has a cell structure in which a pair of electrodes regularly arranged on two opposing glass substrates are provided, and a gas mainly composed of Ne or the like is sealed between each pair of electrodes. By applying a voltage between the electrodes of these cells and causing discharge in minute cells around the electrodes, the light emitters in each cell emit light and display is performed. One of the reasons why it is easy to increase the size of the PDP is that a screen printing method can be used for manufacturing a panel having such a structure.

  As described above, the screen printing method is easy to enlarge, but as a photomask for producing the screen plate, conventionally, a chromium film is formed on a glass substrate by sputtering or the like and etched. A pattern is used. The chromium film formed on this glass substrate has good adhesion and uniformity.

  However, film formation by such a sputtering method is performed in a vacuum, and if the target device is enlarged, a large substrate is required, and a chamber that can accommodate a large substrate is required. In order to uniformly form a film on a large substrate, the apparatus becomes large, and more advanced control is required. Therefore, a mask formed using the sputtering method is difficult to manufacture and is expensive. It is a thing.

  However, as described above, there is a method of forming a metal thin film by performing electroless plating as a method for forming a film on a glass substrate without using a vacuum technique. By this method, a photoresist film made of a photosensitive resin is formed on the produced metal thin film, the pattern is exposed and developed, and etched after image formation to form a pattern. Using this pattern as a photomask, a screen plate Since it can be used to manufacture a large-sized mask at low cost, it contributes to the future development of PDP.

  However, since glass is a substrate with high smoothness, when electroless plating is performed, a large area often causes clouding, swelling, peeling, etc., and can be used as a photomask. Almost never. Furthermore, many defects such as mouse clips occur during etching.

  In view of such a situation, an object of the present invention is to perform electroless plating on a glass substrate, obtain a photomask therefrom, and a plated metal layer that is comparable to a chromium mask produced by a sputtering method. An object of the present invention is to provide a method for producing a screen plate for screen printing, which has good adhesion to a substrate and can obtain, for example, a large screen plate for PDP at low cost using this photomask.

  That is, the present invention (1) forms a metal film by performing electroless plating on a glass substrate, forms a photoresist (photosensitive resin) film thereon, exposes and develops the pattern, and forms an image. A method for producing a screen plate for screen printing, characterized in that a pattern is formed by etching later and this pattern is used as a photomask.

  In this manufacturing method, (2) the electroless plating is Ni—P plating, (3) the film thickness of the electroless Ni—P plating is 0.3 μm or less, and (4) the electroless Ni. -The optical density of the P plating film is 3.5 to 4.5, (5) In the pretreatment of electroless plating, the glass substrate is immersed in an aqueous solution of acidic stannous chloride having a concentration of 10 g / L or less. And a catalyst activation treatment by immersing the glass substrate in a palladium chloride aqueous solution having a concentration of 1 g / L or less, (6) a heat treatment after forming a metal film, (7 ) The size of the glass substrate is preferably 500 mm × 500 mm or more.

  According to the present invention, a large screen printing screen plate for PDP can be obtained at low cost. In particular, by optimizing pre-treatment before plating, plating bath, post-treatment, etching solution, etc., a photomask with good adhesion between the substrate and the plated metal layer comparable to a chromium mask produced by sputtering method A mask is obtained, and a large screen plate for screen printing can be produced at low cost.

(Manufacture of photomasks)
In the present invention, first, a metal film is formed on a glass substrate by electroless plating, a photoresist film is formed thereon, the pattern is exposed and developed, an image is formed, and then etched to form a pattern. A photomask is manufactured.

  Examples of the electroless plating include copper plating, Ni plating, cobalt plating, and the like. Ni-P plating is preferable because a plating bath is stable and a film having high adhesion can be obtained. Further, as the glass substrate, a light transmissive glass plate such as soda lime glass plate or non-alkali glass is used, and the soda lime glass plate is preferable in terms of light transmittance and cost. Since the size of the glass substrate is intended to produce a large PDP, it is preferable to use a glass substrate having a size of 500 mm × 500 mm or more. In the present invention, since the electroless plating technique is used without using the vacuum technique, such an increase in size can be easily achieved, which is advantageous in terms of cost.

  In electroless plating, the glass substrate is pretreated and electroless plating is performed. In the pretreatment, the surface of the substrate is etched, and then a catalyst is applied to the surface for electroless plating by sensitization treatment and catalyst activation treatment.

The glass substrate is etched after the substrate is washed with water to remove dirt adhered to the substrate surface. It is preferable to perform ultrasonic cleaning in pure water and further at room temperature for 1 to 10 minutes, preferably 5 minutes. Thereafter, it is immersed in an etching treatment solution. Examples of the etching treatment liquid include NaOH aqueous solution, HNO ₃ aqueous solution, HF aqueous solution, H ₂ SO ₄ aqueous solution, and methanol solution containing methylate (CH ₃ ONa). And an etching process immerses a glass substrate in the single solution of these solutions, or immerses these solutions in combination.

In the case of the NaOH aqueous solution, it is immersed at 0.1 to 3 mol / L, preferably 1 mol / L, for 10 to 60 seconds, preferably 30 seconds. In the case of an HNO ₃ aqueous solution, it is immersed at 0.1 to 2 mol / L, preferably 1 mol / L, for 10 to 60 seconds, preferably 30 seconds. In the case of an HF aqueous solution or the like, it is immersed at 0.1 to 2 mol / L, preferably 1 mol / L, for 10 to 60 seconds, preferably 30 seconds. In the case of the H ₂ SO ₄ aqueous solution, it is immersed at 0.1 to ₄ mol / L, preferably 1 mol / L, for 10 to 60 seconds, preferably 30 seconds. In the case of a methanol solution containing methylate, NaOH forms a methylate in methanol, and the content as NaOH is 1 to 20%, preferably 10% to 10 to 40 ° C, preferably 1 to room temperature. Soak for 10 minutes, preferably 3 minutes.

Further, when combining these treatments, for example, (1) soaked in an aqueous NaOH solution and then soaked in an aqueous HF solution, (2) soaked in an aqueous NaOH solution and then soaked in an aqueous HF solution, soaked in methanol or ethanol. 3) After immersing in NaOH aqueous solution, immersing in HF aqueous solution and immersing in methanol solution containing methylate. The case (3) is most preferable. In this case, NaOH sequentially breaks down the glass network structure, and HF reacts with silicic acid (SiO ₂ ) constituting the glass, thereby breaking the —Si—O—Si— bond. Then, fluorinated silicon acid (Na ₂ SiF ₆ ) is generated. This reaction proceeds sequentially on the glass surface and etching is performed. Then, CH 3 _ONa -SiONa is generated on the glass surface by, increased hydrophilicity, the electroless plating catalyst is effectively applied in a later step. In addition, you may perform water washing operation arbitrarily during these immersion treatment of (1)-(3). Further, as in the examples, (1) the substrate may be immersed in an aqueous NaOH solution, washed with water, immersed in an aqueous H ₂ SO ₄ solution, and washed with water.

  Further, the catalyst is applied to the glass substrate that has undergone the pretreatment process as described above. When the electroless plating is Ni—P plating, the adhesion catalyst is Pd, and the catalyst is applied as follows. That is, the sensitization treatment is performed by immersing in an acidic stannous chloride aqueous solution, and then the catalyst activation treatment is performed by immersing the glass substrate in an aqueous palladium chloride solution. In the sensitization treatment, the immersion is performed at 10 to 40 ° C., preferably at room temperature, and the stannous chloride concentration is 10 g / L or less, preferably 0.1 to 1.0 g / L. In the catalyst activation treatment, the immersion is performed at 10 to 40 ° C., preferably at normal temperature, and at a palladium chloride concentration of 1 g / L or less, preferably 0.01 to 0.1 g / L. This sensitization treatment and catalyst activation treatment are preferably repeated 1 to 5 times, preferably 2 to 3 times, with a water washing operation. In this way, the catalyst is applied to the glass substrate.

  Further, the substrate to which the catalyst has been imparted by sensitization and catalyst activation treatment is immersed in a bath containing a metal salt, a reducing agent, and a complexing agent, and a metal film is formed on the substrate by electroless plating. In the case of electroless Ni-P plating, nickel sulfate is 0.02 to 0.25 mol / L, preferably 0.1 mol / L, and sodium hypophosphite is 0.05 to 0.3 mol / L, preferably 0. .2 mol / L, in a plating bath composed of glycine 0.1-0.7 mol / L, preferably 0.4 mol / L, temperature 40-90 ° C., preferably 60 ° C., time 10-100 minutes, Preferably, electroless plating is performed for 30 minutes to form a Ni—P plating film having a film thickness of 0.3 μm or less, preferably 0.1 to 0.28 μm. The pH of the bath at that time is 4.0 to 9.0, preferably pH 4.5. In particular, by setting the bath conditions to 60 ° C. and pH 4.5, the plating film can be grown slowly, and the adhesion strength between the plating film and the substrate can be increased. In order to use the plating film formed on the glass substrate as a photomask for producing a screen plate for screen printing, the film thickness of the plating film formed on the glass substrate is adjusted to obtain an optical density. Is preferably from 3.5 to 4.5, preferably approximately 4.0.

  Further, the metal film formed on the substrate is heat-treated in air at 50 to 250 ° C., preferably 100 to 250 ° C. The heat treatment time is 10 to 60 minutes, preferably 15 to 45 minutes. By performing heat treatment, moisture and hydrogen taken into the plating film are dissipated, and metal particles (Ni particles in the case of Ni-P plating) are generated in the pretreatment and are formed in the recesses on the substrate. ) Enters and this exerts an anchor effect to improve the adhesion between the plating film and the substrate.

  Further, a photoresist film made of a photosensitive resin is formed on the metal film formed on the substrate. Note that the photoresist to be used may be a positive type resist from which a portion irradiated with light is removed or a negative type resist from which a portion not irradiated with light is removed. The method for forming the photoresist film may be a method of forming a coating film by applying a paint in which a photosensitive resin is dissolved in a solvent, or a method of forming a film of a photosensitive resin on a substrate. Next, the pattern is exposed, the exposed or unexposed photoresist film is dissolved in a solvent and removed, and the exposed electroless plating layer portion is nitric acid: phosphoric acid: water = 2-20: 20-80: When the remaining photoresist film is removed by dipping in a solution composed of 1 to 60, preferably 8:70:22, and removed by etching, a glass plate on which the plating layer is patterned is obtained. This is used as a photomask for a screen plate for screen printing.

  In addition, the photomask manufactured by the above method has a so-called white defect in which the light-shielding portion has been lost for some reason, or a so-called black defect in which the electroless plating layer that is the light-shielding portion has been protruded for some reason. May occur. However, the white defect can be corrected by a conventional technique such as applying a metal paste to the defective portion and firing, and the black defect is also cut by, for example, a second harmonic pulse oscillation laser of a YAG laser. Therefore, it is possible to cope with the conventional technique of performing correction.

  This photomask can be used not only for the production process of a general screen printing screen plate, but also preferably used as a mask substrate for exposure used in the production of flat display panels, especially PDPs that are required to be enlarged. it can.

(Manufacture of screen plates for screen printing)
A screen plate for screen printing is produced using the photomask obtained as described above.
As shown in FIG. 1, a screen (frame) is stretched on the frame, a frame is formed, a photosensitive emulsion is applied on the screen and dried, and a patterned photomask is placed on the screen. , Exposing to form a latent image, and dissolving and removing the unexposed portion in a solvent such as water to develop a screen printing plate.

For example, a rectangular frame of a predetermined size made of aluminum or the like, a metal fiber such as a soot made of chemical fibers such as a polyester screen or a nylon screen, or a so-called rigid screen in which a stainless steel or stainless mesh surface is coated with nickel plating. Apply a light-sensitive emulsion on the screen. After drying the photosensitive emulsion, a photomask having a predetermined pattern is brought into close contact with the photosensitive emulsion surface and exposed. The photosensitive emulsion in the exposed area undergoes a photochemical reaction and changes to water-insoluble, but the photosensitive emulsion under the opaque part of the photomask remains unreacted, so when developed with water or hot water, The photosensitive emulsion melts to form a pattern. Thereafter, draining and drying are performed to obtain a screen plate for screen printing.
The screen printing screen plate thus obtained can be used for printing a PDP phosphor or for producing a back surface electrode or a surface electrode.

  In the above-described method, a manufacturing example of a so-called direct-stretched screen plate in which a printing screen is directly stretched on a rectangular frame is shown, but the printing screen is stretched on the quadrangular frame via a support screen. A so-called combination screen plate may be manufactured.

  In addition, whether you manufacture a straight screen plate or a combination screen plate, the plate manufacturing conditions such as frame size, screen material, and mesh are changed to the conditions that match the device to be printed. Needless to say.

Hereinafter, the present invention will be specifically described with reference to examples.
(Manufacture of photomasks)
[500 mm × 500 mm × 4.8 mm (thickness)] soda lime glass is used as a substrate for the plating base, and the substrate is subjected to ultrasonic cleaning in pure water at room temperature for 5 minutes, and then 1 mol / L. It was immersed in an aqueous NaOH solution for 30 seconds and washed with water. Then, after being immersed in 1 mol / L H ₂ SO ₄ aqueous solution for 30 seconds, ultrasonic cleaning was performed in pure water.

The substrate cleaned as described above is further sensitized by immersion in a 1.0 g / L SnCl ₂ aqueous solution at room temperature for 60 seconds, and immersed in a 0.1 g / L PdCl ₂ aqueous solution at room temperature for 60 seconds. The catalyst was activated. This sensitization treatment and catalyst activation treatment were repeated three times with a water washing operation.

  Further, the substrate subjected to the sensitization and catalyst activation treatment was subjected to plating bath (pH: 4.5) composed of nickel sulfate 0.1 mol / L, glycine 0.4 mol / L, and sodium hypophosphite 0.2 mol / L. , Bath temperature: 60 ° C.) for 30 minutes to form a 0.3 μm thick Ni—P plating layer. The optical density at this time was 4.0. Further, the metal film formed on the substrate was heat-treated in an air atmosphere at 150 ° C. for 30 minutes.

A positive resist AZP1350 manufactured by Hoechst Co. was applied onto the substrate on which the Ni-P plating layer was formed by spin coating so that the thickness after drying would be 0.8 mm to 1.0 mm. Next, by using a device in which an LED laser is mounted on a laser plotter FR8500 (VIOLD) manufactured by Dainippon Screen Manufacturing Co., Ltd., a predetermined pattern consisting of a portion irradiated with laser light and a portion not irradiated with laser light is formed. Form. Thereafter, development was performed at 22 ° C. for 1 minute 30 seconds using a mixture of sodium metasilicate nonahydrate (Na ₂ SiO ₃ .9H ₂ O) mixed with pure water at a constant ratio, and irradiation with laser light. The portion is removed to form a patterned resist layer. Then, the electroless plating part exposed by immersion in an etching solution composed of nitric acid: phosphoric acid: water = 8: 70: 22 is etched, and a stripping solution that is a mixed solution of sodium hydroxide and pure water is used. By dipping and stirring at room temperature for 5 minutes, the resist film remaining on the substrate was peeled off, washed with water, and dried to obtain a photomask having a patterned electroless plating layer on the substrate. The adhesion between the substrate and the plating layer in this photomask was not recognized at all in the JIS standard tape peeling test, and there was no problem with the adhesion.

(Manufacture of screen plates for screen printing)
Stainless steel woven with a mesh size of 620 × 620 mm and a wire diameter of 20 μm and a mesh of 290 mesh with a synthetic fiber woven with a mesh size of 900 μm × 900 mm and 225 mesh with a wire diameter of 55 μm. A rigidized screen in which the surface of the screen mesh was coated with a plating of 3 μm in thickness was used as a printing screen to form a combination screen at a bias angle of 22.5 °. Next, the photosensitive emulsion is applied to the printing screen portion at a thickness of 10 μm, dried, and the photomask having the pattern obtained as described above is adhered to the photosensitive emulsion portion, and the exposure amount is 1500 mJ with an ultrahigh pressure mercury lamp. / Cm < ² >. Then, after developing with water and drying, a pattern with a photosensitive emulsion was formed on the printing screen, and a screen plate for screen printing was produced.
When the screen printing screen plate thus obtained was used for printing a PDP phosphor, the phosphor could be uniformly printed.

  The screen printing screen plate obtained in the present invention is intended to produce a large-size PDP, but can also be used for screen printing plates of various other large devices.

It is a figure which shows the manufacturing process of a screen printing plate.

Claims (7)

  Electroless plating is performed on a glass substrate to form a metal film, a photoresist film is formed thereon, the pattern is exposed / developed, and etching is performed after image formation to form a pattern. A method for producing a screen plate for screen printing, which is used as a mask.   2. The method for producing a screen plate for screen printing according to claim 1, wherein the electroless plating is Ni-P plating.   3. The method for producing a screen plate for screen printing according to claim 2, wherein the film thickness of the electroless Ni-P plating is 0.3 [mu] m or less.   4. The method for producing a screen printing screen plate according to claim 3, wherein the electroless Ni-P plating film has an optical density of 3.5 to 4.5.   In the pretreatment of electroless plating, the glass substrate is immersed in an acidic stannous chloride aqueous solution having a concentration of 10 g / L or less, and sensitized, and further immersed in an aqueous palladium chloride solution having a concentration of 1 g / L or less. The method for producing a screen plate for screen printing according to any one of claims 1 to 4, wherein a catalyst activation treatment is performed.   6. The method for producing a screen printing screen plate according to claim 1, wherein the heat treatment is performed after forming the metal film.   The size of a glass substrate is 500 mm x 500 mm or more, The manufacturing method of the screen plate for screen printing in any one of Claims 1-6 characterized by the above-mentioned.

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