JP2006103223A - Manufacturing method of metal mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a metal mask which keeps the smoothness of the inner wall of an opening part enhanced and thereby stabilizes the quantity of application of a solder paste. <P>SOLUTION: The opening part of a pattern for printing is formed in a metal plate 10 by exposure to a laser light. An abrasive solution containing minute abrasive grains is encapsulated in the opening part and the inner wall of the opening part is polished by applying vibration to the metal plate 10. Then, an abrasive material consisting of the abrasive solution 30 and extremely thin fibers 50 is brought into contact with the inner wall 12 of the opening part to polish the inner wall 12. The abrasive solution 30 is a mixture of a nitrate containing minute abrasive grains 31 of alumina and water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a metal mask having an opening for a printing pattern.

  In general, a metal mask is used to form a printed pattern on a wiring board. This printed pattern is formed by placing a metal mask on the top of the wiring substrate, applying solder paste to the pattern opening of the metal mask with a squeegee, and lifting the metal mask to apply the solder paste to the wiring substrate. .

  In order to stabilize the amount of solder paste applied, it is necessary to reduce the surface roughness of the inner wall of the opening of the metal mask. As a method for reducing the surface roughness of the inner wall of the opening, there is known a method in which a granular abrasive is sprayed and sandblasted (see Patent Document 1).

However, since the opening of the metal mask has been narrowed due to the miniaturization of electronic components and the use of solder paste that does not contain lead and has excellent fluidity, the smoothness of the inner wall of the opening has been increased and solder has been used. There is a demand for stabilizing the amount of paste applied.
JP-A-9-57937

  The present invention has been proposed in view of such a situation, and an object of the present invention is to provide a method for manufacturing a metal mask that increases the smoothness of the inner wall of the opening and stabilizes the amount of solder paste applied.

  That is, the invention of claim 1 irradiates a metal plate with a laser beam to form a pattern opening for printing, encloses an abrasive solution containing fine abrasive grains in the opening and applies vibration to the metal plate. Then, the inner wall of the opening is polished, and then the inner wall is polished by bringing the abrasive solution and an ultrafine fiber into contact with the inner wall of the opening.

  A second aspect of the present invention relates to the method of manufacturing a metal mask according to the first aspect, wherein the abrasive solution is a mixed solution of nitrate and water containing fine abrasive grains of alumina.

  Invention of Claim 3 concerns on the manufacturing method of the metal mask in which the said ultrafine fiber is a melamine resin foam in Claim 1.

  According to the metal mask manufacturing method of the first aspect of the invention, a pattern opening for printing is formed by irradiating a metal plate with laser light, and an abrasive solution containing fine abrasive grains is enclosed in the opening. Since the inner wall of the opening is polished by applying vibration to the metal plate, and then the inner wall is polished by contacting the abrasive solution made of the abrasive solution and ultrafine fibers with the inner wall of the opening. The metal mask which raises the smoothness of this and stabilizes the application quantity of solder paste can be manufactured.

  According to the invention of claim 2, since the abrasive solution is a mixed solution of nitrate and water containing fine abrasive grains of alumina in claim 1, the inner wall of the opening is formed by fine abrasive grains. While smoothing, the inner wall of the opening can be washed with a mixed solution of nitrate and water.

  According to the invention of claim 3, since the ultrafine fiber is a melamine resin foam in claim 1, the smoothness of the inner wall of the opening can be increased by an inexpensive ultrafine fiber.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a schematic side view showing a step of forming a pattern opening by laser light in a metal mask manufacturing method according to one embodiment of the present invention, FIG. 2 is a schematic sectional view of a pattern opening by laser processing, and FIG. FIG. 4 is a schematic cross-sectional view showing the step of polishing the inner wall of the pattern opening with an abrasive solution containing abrasive grains, and FIG. 4 is a schematic cross-section showing the step of polishing the inner wall of the pattern opening with the abrasive solution and ultrafine fibers. FIG. 5 and FIG. 5 are graphs showing the relationship between the number of solder printed sheets and the weight of the solder paste removed.

  As shown in FIG. 1 and FIG. 2, a pattern opening 11 for printing is formed by irradiating a metal plate 10 with a laser beam 1 by a metal mask manufacturing method according to the present invention. The metal plate 10 is installed on the XY table 20 of the laser processing apparatus. As shown in the figure, the laser head 5 is disposed on the top of the XY table 20. The metal plate 10 is moved by the XY table 20, and a predetermined pattern opening 11 is formed by the laser light 1 from the laser head 5. Here, the metal plate 10 is formed of a SUS304 plate having a thickness of 0.04 mm. Reference numeral 25 denotes a frame for the laser processing apparatus.

  In the opening 11 of the metal plate 10, a melt produced by laser processing is attached to the inner wall 12. As shown in the figure, the inner wall 12 also has unevenness due to laser processing. As shown in FIG. 3, the metal mask manufacturing method according to the present invention encloses an abrasive solution 30 containing abrasive grains 31 in the opening 11, and applies vibration to the metal plate 10 to cause an inner wall of the opening 11. 12 is polished. As a result, the melt adhered to the inner wall 12 can be removed and the inner wall 12 can be smoothed.

  The abrasive solution 30 is injected into the opening 11 with a dropper. The abrasive solution 30 is enclosed in the opening 11 by the metal thin plate 40 closing the opening 11. The thin plate 40 is fixed to the metal plate 10 by a known semiconductor UV tape 45.

  The metal plate 10 is vibrated by a known sander polisher (Ryobi Corporation, DSP-125V). In this example, the sander polisher rotated 8000 to 9000 per minute with no load applied to the metal plate 10. The abrasive grains 31 move when vibration is applied to the front and back surfaces of the metal plate 10 to polish the inner wall 12 of the opening. Here, vibration was applied to the surface of the metal plate 10 for 15 minutes and then applied to the back surface for 15 minutes. After finishing this polishing, the thin plate 40 is removed and the opening 11 is washed with water.

  Next, as shown in FIG. 4, the inner wall 12 is polished by bringing the abrasive solution 30 and the fine fiber 50 into contact with the opening inner wall 12. The abrasive solution 30 is injected into the opening 11 with a dropper. The abrasive solution 30 becomes substantially spherical due to surface tension and adheres to the opening 11. As shown in the drawing, the ultrafine fiber 50 forming the abrasive enters the opening 11 and polishes the inner wall 12 together with the abrasive grains 31. Here, the inner wall 12 is polished by reciprocating the ultrafine fiber 50 30 times in the vertical direction and the horizontal direction. The ultrafine fibers 50 reciprocate manually or automatically.

  Since the extra fine fiber 50 is 1 / 10,000th the thickness of the hair, it can enter the opening 11 and the eraser can rub off the dirt to increase the smoothness of the inner wall 12. The polished inner wall 12 is finished to a smooth surface such as a mirror surface. As a result, the solder paste is applied to the wiring board through the inner wall 12 having high smoothness, and the amount of solder paste applied can be stabilized. The manufacture of the metal mask 10 ends when the opening 11 is washed with water.

  In this example, as defined in the invention of claim 2, the abrasive solution 30 was a mixed solution of nitrate and water containing fine abrasive grains of alumina. The abrasive | polishing agent solution 30 of an Example is a well-known polishing compound for mirror polishing (Brand name: MECANOX DN-3, Uemura Kogyo Co., Ltd. product). The alumina abrasive grains have an average particle size of 0.37 to 0.43 μm. Since the alumina abrasive grains (abrasive) have a small particle diameter, they can enter the narrow opening 11, and the inner wall 12 can be polished and smoothed. The abrasive solution 30 is a mixture of nitrate (polishing aid) and water, and cleans the inner wall 12.

  The ultrafine fiber 50 of the example was a melamine resin foam as defined in the invention of claim 3. As a result, the smoothness of the opening inner wall 12 can be enhanced by inexpensive ultrafine fibers.

  Each evaluation and evaluation method of Examples and Comparative Examples are shown below. Solder paste was evaluated for removal by comparing the weights of the examples and comparative examples. Table 1 shows a metal mask manufacturing method and the like for comparison. The missing weight is the amount that the solder paste passes through the opening 11 of the metal mask 10, and was obtained by subtracting the weight of the wiring board before printing from the weight of the wiring board after solder printing. Here, the removal weight was obtained using 60 wiring boards as shown in FIG. When the removal weight is large, the smoothness of the inner wall 12 of the opening is high and the amount of solder paste applied is stabilized.

  The state of solder printing was visually confirmed and evaluated. Here, the shape of the solder paste was confirmed with a digital HD microscope (manufactured by Keyence Corporation, VH-7000). In addition to this, whether or not the solder paste could not pass through the opening 11 and adhered to the opening 11 of the metal mask 10 after solder printing was also confirmed by visual inspection and evaluated. Tables 2 and 3 show the manufacturing method of the metal mask to be compared and the visual evaluation.

It is a schematic side view which shows the process of forming a pattern opening part with a laser beam among the manufacturing methods of the metal mask which concerns on one Example of this invention. It is a schematic sectional drawing of the pattern opening part by laser processing. It is a schematic sectional drawing which shows the process of grind | polishing the inner wall of a pattern opening part with the abrasive | polishing agent solution containing an abrasive grain. It is a schematic sectional drawing which shows the process of grind | polishing the inner wall of a pattern opening part with the said abrasive | polishing agent solution and an ultrafine fiber. It is a graph which shows the relationship between the number of solder printed sheets and the weight of the solder paste.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam 10 Metal plate 11 Pattern opening part for printing 12 Inner wall of pattern opening part 30 Abrasive solution 31 Abrasive grain 50 Extra fine fiber

Claims (3)

Irradiate a metal plate with laser light to form a pattern opening for printing,
While encapsulating a polishing agent solution containing fine abrasive grains in the opening and applying vibration to the metal plate to polish the inner wall of the opening,
Next, the inner wall is polished by bringing the abrasive solution and an ultrafine fiber abrasive into contact with the inner wall of the opening. A method for producing a metal mask.   The method for producing a metal mask according to claim 1, wherein the abrasive solution is a mixed solution of nitrate and water containing fine abrasive grains of alumina.   The method for producing a metal mask according to claim 1, wherein the ultrafine fiber is a melamine resin foam.

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