JP2010069835A - Screen printing mask, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the printing resistance and paste omission of a screen printing mask by coating the surface of a photosensitive emulsion and plain gauze formed with a pattern in the screen printing mask, with a protective film excelling in corrosion resistance and lubricating ability. <P>SOLUTION: Plasma treatment using carbon-containing compound gas of plasma generating raw material gas is applied to the screen printing mask formed with a predetermined pattern with a photosensitive emulsion on the plain gauze to modify the surface of the photosensitive emulsion and gauze, and a protective film is formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screen printing mask used for manufacturing electronic parts and the like and a technique for manufacturing the same.

In recent years, the application of screen printing has been greatly expanded in the field of manufacturing electronic components. In particular, surface mount type resistors and capacitors called chip components have been miniaturized, and the size is as small as 0.6 mmW x 0.3 mmL (0603 type) and 0.4 mm x 0.2 mm (0402 type). It has been commercialized.
Moreover, although it is used also for electrode formation of flat panel displays (plasma, liquid crystal display etc.), high printing accuracy is requested | required with the enlargement and high definition of a display.

  The mask for screen printing is generally knitted with a plate frame, for example, aluminum die-casting or aluminum pipe, which is fixed with an adhesive or packing, for example, metal fibers or synthetic fibers such as Tetron and polyester. The surface of the mesh fabric is coated with a photosensitive emulsion, and a layered product is exposed to light using a photomask patterned on a film or glass, or exposed to a laser to form a pattern, and a developer, for example, Developed with water. When printing is performed using a screen printing mask, a squeegee such as urethane rubber is used, and printing is performed by a transfer mechanism. A high-definition screen printing mask in recent years is manufactured by the same method, but the screen printing mask tends to have a fine pattern to be printed and a thin printed film thickness.

  However, when a pattern is formed using a photosensitive emulsion for the preparation of a high-definition screen printing mask in recent years, the hardness of the photosensitive emulsion is low, so that the printing or mask is compared with a screen printing mask that is not high-definition. As a result of this cleaning, the patterned emulsion layer is worn and deformed, causing printing misalignment and damage to the screen printing mask due to deterioration of flatness. Must be exchanged.

In addition, it is shown that plasma coating treatment is performed on the ridge which is the base of the screen printing mask to increase the adhesive strength with the photosensitive emulsion, and as a result, the photosensitive emulsion is difficult to peel off during use. .

Also,
In order to improve the dimensional stability and wear resistance of the photosensitive emulsion by electroforming (electroforming method), the pattern formation is performed by plating. There are also attempts to solve it.

No. 2695633 No. 4113906

  However, even when the above techniques are applied, in high-definition screen printing masks with an extremely thin emulsion thickness and a fine minimum pattern, photosensitive emulsions are repeatedly subjected to friction due to squeegees during printing and plate washing. Wear and delamination occur. The reason for this is that the minimum pattern portion has a pattern that is substantially the same as or close to the wire diameter of the cocoon as the mesh line becomes thin.

  In addition, when the emulsion thickness was extremely thin, a pattern was formed even when plasma coating was applied to the base of the screen printing mask referred to in the aforementioned patent document to increase the adhesive strength with the photosensitive emulsion. The durability of the photosensitive emulsion itself has not been improved.

  In addition, a screen printing mask formed with a metal pattern by the electroforming method (electroforming method) referred to in the above-mentioned patent document is effective for a soft printed material. For high-definition flat panel displays and hard substrates such as glass and alumina, which are printed boards for small chip components, they are metal, so they are inflexible and have poor adhesion, which can interfere with printing. It may come, and it cannot be said that it is versatile.

With the above-described technology, it has been difficult to solve the problem of high-definition screen printing masks, and therefore a screen printing mask that can be printed by a new manufacturing method has been desired.
In addition, there is no report on a technique for forming a protective film by plasma treatment for a material having high flexibility such as a photosensitive emulsion or an object in which a metal, a nonmetal and a resin are mixed.
Accordingly, in order to solve the above-described problems, an object of the present invention is to realize a screen printing mask and a manufacturing method thereof.

In order to solve the above-mentioned problems, the present invention is directed to the plasma treatment after surface modification of the wrinkles fixed on the plate frame and the photosensitive emulsion portion having a printed pattern formed on the surface of the wrinkles by plasma treatment. And a mask for screen printing, comprising a protective film. The protective film is a DLC (diamond-like carbon) film. In addition, the thickness of the protective film is 0.5 nm to 20 μm. Further, the protective film is provided on one side or both sides of the screen printing mask.
The photosensitive emulsion portion of the screen printing mask is characterized by being in the center of the ridge fixed to the plate frame. Further, the protective film of the screen printing mask is characterized in that it is on the photosensitive emulsion portion and the ridge around it.
In addition, the screen printing masks can be directly stretched (patterned directly with a stencil on the plate frame) or combination method (stencils with a base stencil on the plate frame, with the main mesh as the center) Regardless of whether the material is a woven or patterned pattern, and the material of the cocoon is a metal fiber or a synthetic fiber, the surface treatment is modified by plasma treatment, and then a protective film is provided by the plasma treatment. Is a mask for screen printing.

The present invention is characterized in that after the surface of the ridge fixed to the plate frame and the photosensitive emulsion portion having a printed pattern formed on the surface of the ridge is modified by plasma treatment, a protective film is provided by the plasma treatment. This is a method for manufacturing a mask for screen printing.
Furthermore, in the process of manufacturing a mask for screen printing, a photosensitive emulsion is coated on the surface of the ridge fixed to the plate frame, and the pattern is formed by exposing it to a layered photomask by exposure or laser irradiation. After the step of forming and developing, the carbon-containing compound gas of the raw material gas for plasma generation is introduced under reduced pressure of 1 to 1 × 10 ⁻⁴ Pascal, subjected to plasma treatment at a low temperature, and fixed to the plate frame And forming a print pattern on the surface of the wrinkles fixed to the plate frame and the surface of the wrinkles while modifying the surface of the wrinkles in the photosensitive emulsion portion in which the print pattern is formed on the surface of the wrinkles and the pattern without the photosensitive emulsion. A method for producing a mask for screen printing, comprising a step of forming a protective film on the photosensitive emulsion portion and the ridge around the photosensitive emulsion portion.
Among them, the step of forming a protective film includes a step of forming a DLC (diamond-like carbon) film by plasma treatment. As a form of mask for screen printing, the direct tension method (patterned directly by stenciling the plate frame) or the combination method (stenciling the base stencil on the plate frame and pasting around the mesh called the main mesh, Regardless of the material of the pattern, and regardless of the material of the bag, after the surface modification by the plasma treatment, a protective film is provided by the plasma treatment, and a mask for screen printing is produced. Is the method.

  According to the present invention, there is provided a screen printing mask provided with a protective film by modifying the surface of a wrinkle fixed to a plate frame and a photosensitive emulsion portion having a printing pattern formed on the surface of the wrinkle using plasma treatment, and a protective film. The manufacturing method makes use of the characteristics of the DLC film, which is a protective film, to make the photosensitive emulsion durable and to reduce the friction coefficient between the photosensitive emulsion part and the heel part to achieve uniform print film thickness, paste removal, and dimensional stability. It became possible to give sex.

  Hereinafter, embodiments of the invention will be described with reference to FIGS.

(1) in FIG. 1 is a plan view of a mask for screen printing produced in a step before the plasma treatment, and (2) in FIG. 1 is a cross-sectional view taken along line AA ′ shown in (1).
A photosensitive emulsion 3 is applied to the surface of a mesh fabric knitted with synthetic fibers such as metal fibers or tetron, polyester, etc., such as a collar 2 fixed to a plate frame 1, such as an aluminum die-cast or aluminum pipe, with an adhesive or packing. Coated, layered, exposed to light using a photomask patterned on a film or glass, or exposed to laser to form a pattern, developed with a developer such as water, and then printed paste A photosensitive emulsion portion 12 is prepared that is knitted with no photosensitive emulsion 3 attached so that the photosensitive paste 3 and the printing paste that have been exposed to pass can be passed.
The photosensitive emulsion portion 12 is in the center, and is preferably slightly wider than the width of the print pattern and the squeegee used during printing. Then, only the ridge 2 is formed from the photosensitive emulsion portion 12 to the plate frame 1.
As for ridge 2, any metal fiber, synthetic fiber, or natural fiber can be used as long as it is used as a mask for screen printing. Also, the photosensitive emulsion 3 can be applied as long as it is normally used. If the printing surface is flat when the photosensitive emulsion 3 is coated, the flatness can be maintained. Accuracy is improved. In addition, as a form of screen printing mask, as a fixing method of the ridge 2, a straight tension method (a ridge is applied directly to the plate frame) or a combination method (a ridge 2 as a base is attached to the plate frame, and a ridge called a main mesh is used. 2 is the center). Any fixing method of the rod 2 may be used.

FIG. 2 shows a process outline of a process for performing plasma processing. First, masking is performed by leaving the photosensitive emulsion portion 12 and the surrounding wrinkles 2 that match the print pattern and the width of the squeegee used at the time of printing (hereinafter referred to as a screen).
The power connection terminal 7 is attached to the plate frame of the screen 5 and placed in the chamber 6. (For example, chamber volume 1400mmΦ × 1800mm etc.)

  The power connection terminal 7 is attached to the power introduction terminal 8 in the chamber 6.

The door of the chamber 6 is closed, and the pressure in the chamber 6 is reduced to 1 to 1 × 10 ⁻⁴ Pascals with the vacuum pump 9.

  After reaching the target degree of vacuum, the carbon-containing compound gas 13 as a plasma generating raw material gas, for example, a gas containing carbon is introduced into the chamber 6 through a mass flow controller 10 containing, for example, methane, acetylene, benzene, toluene and the like.

  After reaching the target degree of vacuum, plasma is generated using a pulse power supply 11 having a maximum rating of −30 KV15A to modify the surface of the photosensitive emulsion portion 12.

  After sufficiently modifying the surface of the photosensitive emulsion portion 12, a carbon-containing compound gas 13 as a plasma generating raw material gas is passed through the mass flow controller 10 and introduced into the chamber 6 while inclining the gas. Even during film formation, the flow rate of the carbon-containing compound gas 13 as the raw material gas for plasma generation, the voltage of the pulse power source 11 and the current pulse width are controlled so that a high temperature (400 ° or more) does not occur in the photosensitive emulsion portion 12. If it exceeds 400 °, the photosensitive emulsion 3 may be damaged by heat.

  After the surface modification and film formation of the photosensitive emulsion part 12, the supply of the pulse power supply 11 is immediately stopped, and the carbon-containing compound gas 13 as the plasma generating raw material gas in the chamber 6 is sufficiently exhausted. Then, air purge is performed. When the atmospheric pressure is reached, the door of the chamber 6 is opened, the power connection terminal 7 is removed from the power introduction terminal 8, and is taken out of the chamber 6. The screen 5 is removed from the power connection terminal 7.

  Since the photosensitive emulsion portion 12 is a kind of dielectric, electric charges accumulate during plasma processing, abnormal discharge may occur, and the screen 5 may be damaged. Although it is necessary to control the current, voltage, pulse width, and flow rate of the carbon-containing compound gas 13 as the plasma generating raw material gas corresponding to the above state, details will not be disclosed.

  (3) of FIG. 3 is a plan view of the screen printing mask according to the present invention, and (4) is a cross-sectional view of (3) B-B ′. The protective film 4 is formed by the photosensitive emulsion portion 12 at the center of the plate frame 1 and the ridge 2 around it. The presence of the protective film 4 on one or both sides of the photosensitive emulsion portion 12 is effective in reducing the coefficient of friction that occurs during printing.

  FIG. 4 is an enlarged cross-sectional view taken along the line C-C ′ shown in FIG. The photosensitive emulsion portion 12 is covered with the protective film 4 by covering all the surface of the light-sensitive emulsion of the photosensitive emulsion portion 12 and the surface of the wrinkles in the pattern portion (front and back surfaces of the photosensitive emulsion portion 12 and 紗 2). 12 can be strengthened, and the abrasion and peeling of the photosensitive emulsion 3 can be suppressed by repeating the friction with the squeegee during printing and the washing of the plate. In addition, by forming a protective film on the photosensitive emulsion portion 12 and the peripheral ridges 2, elongation of the crease due to printing can be suppressed, so that dimensional stability is also improved.

  FIG. 5 shows a structural diagram of the surface modification and the protective film. The surface of the photosensitive emulsion or wrinkle surface portion 15 is modified by plasma treatment, and the protective film 4 is formed on the surface-modified portion 14, so that the inside of the photosensitive emulsion or wrinkle surface portion 15 is not modified. In particular, by ensuring the flexibility inherent to the photosensitive emulsion 3, it becomes a versatile screen printing mask without losing the adhesion to the substrate. The surface of the ridge 2 is also surface-modified and the protective film 4 is formed, so that the elongation of the crease relative to the time of printing can be reduced and a dimension maintaining effect can be obtained. If the thickness of the protective film 4 is less than 0.5 nm, the effect as a protective film cannot be obtained. If the thickness is greater than 20 μm, the film becomes too hard and it is difficult to maintain the flexibility of the photosensitive emulsion 3.

The present invention will be described more specifically with reference to the following examples and comparative examples.
Example 1 and Comparative Example 1
A 400-mesh (wire diameter 23 μm) wrinkle is put on a 320 × 320 mm aluminum die-cast frame, a photosensitive emulsion having a thickness of 10 μm, and a 100 mm square 100 μm line is resolved in the pattern. One is using Example 1 in which a protective film is formed by the process of the present invention and Comparative Example 1 in which a protective film is not formed, printing is performed on a ceramic substrate with a conductive paste (Ag-pt), and a drying furnace It dried at (200 degrees) and measured the printed film thickness (FIG. 6). As a result, it was confirmed that in the printed film thickness, the printed film thickness in Example 1 was larger than that in Comparative Example 1 and was transferred with a stable printed film thickness.

Example 2 and Comparative Example 2
Next, a 400-mesh (wire diameter 23 μm) wrinkle was stretched on a 320 × 320 mm size aluminum die-cast frame, the emulsion thickness of the photosensitive emulsion was 10 μm, and the pattern had a resolution of 25 measurement points within a 100 mm square. Is produced. One is printing with conductive paste (Ag-pt) on a ceramic substrate using Example 1 in which a protective film is formed after patterning and Comparative Example 1 in which a protective film is not formed. Then, it was dried in a drying furnace (200 °), and the dimensions were measured (FIG. 7). As a result, looking at the maximum value of the moving dimension from the initial printing, it is confirmed that the printing accuracy in Example 2 is more effective in maintaining the dimension than Comparative Example 2, and the elongation of wrinkles due to printing is reduced. There was found.

Example 3 and Comparative Example 3
A screen of 250 mm (wire diameter 30 μm) is stretched on an aluminum die cast frame of 320 × 320 mm size, the emulsion thickness of the photosensitive emulsion is 10 μm, and a solid pattern is resolved for the pattern. One is using Example 2 in which a protective film is formed by the process of the present invention after patterning and Comparative Example 2 in which a protective film is not formed, and a glass paste is placed on Benzut TR-F manufactured by Ozu Sangyo Co., Ltd. Printing was performed (printing conditions: printing pressure 200 Mps, clearance 0.8 mm, drop amount 0.9 mm, squeegee hardness 70 °, attack angle 70 °), and the amount of paste passing was measured (FIG. 8). As a result, it was confirmed that the paste passing amount was better in Example 2 than in Comparative Example 2.
In addition, by comparing the amount of paste passing at the same printing pressure, the product of the present invention can be printed at a low printing pressure, which can reduce the printing load of the mask for screen printing. It turned out to be superior to sex.

(1) is a plan view of a screen printing mask produced in the step before the plasma treatment, and (2) is a cross-sectional view taken along line A-A ′ shown in (1). An outline of a process for performing plasma treatment will be described. (3) is a plan view of the mask for screen printing according to the present invention, and (4) is a cross-sectional view shown in (3) B-B ′. The expanded sectional view of C-C 'shown in (3) of Drawing 3 is shown. The structural drawing about surface modification and a protective film is shown. The printing film thickness by the printing frequency of Example 1 and Comparative Example 1 is shown. The maximum value of the dimension elongation at the measurement point according to the number of times of printing in Example 2 and Comparative Example 2 is shown. The passage amount of the paste of Example 3 and Comparative Example 3 is shown.

Explanation of symbols

1 Plate frame 2 紗 3 Photosensitive emulsion 4 Protective film 5 Screen 1
6 Chamber 7 Power connection terminal 8 Power supply introduction terminal 9 Vacuum pump 10 Mass flow controller 11 Pulse power supply 12 Photosensitive emulsion part 13 Carbon-containing compound gas of raw material gas for plasma generation 14 Surface modified part 15 Surface part of photosensitive emulsion or soot

Claims (9)

  A screen printing comprising a ridge fixed to a plate frame and a photosensitive emulsion portion having a printed pattern formed on the surface of the ridge, the surface of which is modified by plasma treatment, and then a protective film is provided by the plasma treatment. Mask.   2. The screen printing mask according to claim 1, wherein the protective film is a DLC (diamond-like carbon) film.   The screen printing mask according to claim 1, wherein the protective film has a thickness of 0.5 nm to 20 μm.   The screen printing mask according to claim 1, wherein the protective film is on one side or both sides of the screen printing mask.   3. The screen printing mask according to claim 1, wherein the photosensitive emulsion is in a central portion of the ridge fixed to the plate frame.   3. The screen mask according to claim 1, wherein the protective film is on the photosensitive emulsion portion and the ridge around it.   A screen printing comprising a ridge fixed to a plate frame and a photosensitive emulsion portion having a printed pattern formed on the surface of the ridge, the surface of which is modified by plasma treatment, and then a protective film is provided by the plasma treatment. Manufacturing method for a mask. In the production process of the mask for screen printing, the carbon-containing compound gas of the raw material gas for plasma generation was introduced in a reduced pressure state of 1 to 1 × 10 ⁻⁴ Pascal, subjected to plasma treatment at a low temperature, and fixed to the plate frame 8. The method for producing a mask for screen printing according to claim 7, further comprising a step of forming a protective film after surface modification of the wrinkles and the photosensitive emulsion portion having a print pattern formed on the surface of the wrinkles. 9. The method for manufacturing a mask for screen printing according to claim 7, wherein the step of forming the protective film includes a step of forming a DLC (diamond-like carbon) film by plasma treatment.