JP2008001107A - Manufacturing process of metal mask of mesh solid-type - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize the thickness of a mask to make the printing thickness uniform even when there are differences in roughness in the density of openings in a method for manufacturing a mesh integral-type metal mask. <P>SOLUTION: Electrodeposition metals 6 corresponding to a mask base plate and waste electrodeposition metals 14 are elctrodeposited on a surface which is not covered with a pattern resist film 11 of an electroforming matrix. Since the amount of electrodeposition per unit area is nearly constant in an electrodeposition method, by forming the waste electrodeposition metals 14 in a region having a high opening density to set the electrodeposition area per unit area in the above region nearly equal to that of a region having a low opening density, the mask thickness of the region having high opening density and that of the region B having low opening density can be made equal to each other. A conductive mesh is superposed closely to the electrodeposition metals 6 having the same mask thickness to form a plating, whereby the mesh can be joined integrally to the electrodeposition metals 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is suitable for screen printing for applying a printed material such as a solder paste on a printed material such as a printed wiring board on which IC, LSI, and other various electronic components are mounted. The present invention relates to a method for manufacturing a body-shaped metal mask.

As this type of mesh-integrated metal mask, for example, a mask substrate having a large number of openings patterned in a desired print pattern by electroforming as disclosed in JP-A-8-183151 is formed. In addition, there is one in which this mask substrate and a conductive mesh are integrated by plating.
JP-A-8-183151

  Such a mesh-integrated electroformed metal mask is superior in chemical resistance and wear resistance compared to a mesh mask made of photosensitive resin, etc., and dimensional changes due to squeegee printing pressure. Extremely small and relatively accurate printing can be expected. In addition, the total thickness of the mask can be easily adjusted even when compared to a mask in which a thin metal foil is integrally bonded on the mesh by electroplating and the metal foil is etched on one side into a desired printed pattern. Different types of metal masks can be easily obtained, and the aspect ratio (total thickness / aperture width) is relatively high, and the mask cross section rises vertically to obtain a high-resolution print pattern. There is an advantage that fine line printing is possible.

  In electroforming, the amount of metal electrodeposited per unit area (electrodeposition amount) is almost constant, so if there is not much difference in opening density over the entire surface of the metal mask, there will be no difference in mask thickness, A substantially uniform pattern mask can be formed. However, in the metal mask, when there is a difference in density between openings depending on location and location, a difference occurs in mask thickness. For example, as shown in FIG. 6 (A), a large number of minute electrodeposited metals 6 exist in the form of solitary islands in the relatively large openings 2 in the metal mask, or as shown in FIG. 7 (A). In the case where a region A in which the opening density is increased by a large number of smaller openings 2 being densely arranged at a small pitch and a region B in which the opening density is decreased by sparsely arranging the openings 2 are present together, A difference in current density occurs during casting, and as shown in FIGS. 6B and 7B, the mask thickness is thicker in the region A where the aperture density is higher and thinner in the region B where the aperture density is lower.

  For this reason, for example, in a metal mask having a thickness of 200 μm, a difference in plate thickness of about 30 to 100 μm occurs in the region A and the region B, although this varies depending on the density of the pattern. 7A, the mesh 5 and the metal mask surface do not sufficiently adhere to each other in the region B where the plate thickness is small as shown in FIG. It can be considered. Further, when the plate thickness difference is extreme, it may not be integrated with the mesh. Furthermore, by using a squeegee for printing, a solder paste film thickness (printing thickness) equal to the thickness of the metal mask can be obtained. Therefore, with a metal mask having a difference in mask thickness, it is necessary to equalize the printing thickness. Even in this case, there is a problem in that a thick print portion and a thin print portion are mixed to cause a difference in print thickness. In addition, in order to eliminate these problems, it is conceivable to make the plate thickness uniform by polishing the surface of the metal mask before integrating with the mesh, but if the plate thickness difference is partially large, It is difficult to polish to a substantially uniform thickness over the entire surface.

  An object of the present invention is to solve these problems. In the above-described method for manufacturing a mesh-integrated metal mask in which a mask substrate is integrally electrodeposited on one side of a mesh, the aperture density is reduced to a high density. Even when there is a difference, the mask thickness can be equalized and the printing thickness can be equalized. Moreover, the objective of this invention is providing the manufacturing method which can obtain such a metal mask easily.

  The invention according to claim 1 of the present invention is such that, as illustrated in FIG. 3, the manufacturing process is illustrated in FIG. 3. On the surface not covered with the pattern resist film 11 of the electroformed mother die 10, the step of patterning the pattern resist film 11 corresponding to each pattern of the discarded electrodeposition openings 12 disposed in the region A, The electrodeposition metal 6 corresponding to the mask substrate 3 and the electrodeposited metal 14 for mask thickness adjustment are formed by electrodeposition, and after electroforming, the electrodeposited metal 14 is removed by etching or manually. A step of stripping, a step of closely polymerizing the conductive mesh 5 on the surfaces of the electrodeposited metal 6 and the pattern resist film 11, a step of integrally bonding the mesh 5 and the electrodeposited metal 6 by plating, and electroforming Matrix 10 Characterized by comprising the al electrostatic Chakukinzoku 6 and a step of separating each section 5.

  The invention according to claim 2 of the present invention is characterized in that, in the invention of claim 1, the discarded electrodeposited metal 14 is removed by etching. That is, as exemplified in FIG. 3, the process of patterning the pattern resist film 11 on the surface of the electroforming mother mold 10 and the surface of the electroforming mother mold 10 not covered with the pattern resist film 11 Further, the process up to the electrodeposition formation of the electrodeposited metal 6 corresponding to the mask substrate 3 and the discarded electrodeposited metal 14 for adjusting the mask thickness is the same as that of the first aspect of the invention. After electroforming, the surface of the electrodeposited metal 6, the discarded electrodeposited metal 14 and the pattern resist film 11 is etched by masking the surface other than the discarded electrodeposited metal 14 with an etching resist film 17. 14 is removed. Next, a liquid resist 19 is filled up to the same height as the pattern resist film 11 in the removed portion of the discarded electrodeposition metal 14 and cured. Thus, the conductive mesh 5 is closely polymerized on the surfaces of the electrodeposited metal 6, the pattern resist film 11 and the cured liquid resist 19. Next, the mesh 5 and the electrodeposited metal 6 are integrally joined by plating. Finally, the electrodeposited metal 6 is peeled off from the electroformed mother die 10 together with the mesh 5.

  According to the first aspect of the present invention, the mask thickness of the region A having a high aperture density where the discarded electrodeposited metal 14 of the metal mask is disposed is such that the discarded electrodeposited metal 14 is not disposed. 7A is thinner than that of the conventional area A having a high opening density, as much as it is electrodeposited on the discarded electrodeposition metal 14. That is, since the amount of electrodeposition per unit area is almost constant in the electrodeposition method, the electrodeposition area per unit area of the region A can be reduced by forming the discarded electrodeposition metal 14 in the region A having a high aperture density. If the electrodeposition area of the region B having a low aperture density is set to approximate, the mask thicknesses of both the region A having a high aperture density and the region B having a low aperture density can be adjusted to be approximately equal.

  Therefore, when printing is performed using this metal mask, the printing thickness can be made uniform throughout. Further, the entire mesh 5 can be uniformly adhered and polymerized on the electrodeposition metal 6 having the same mask thickness and the same height, and the mesh 5 and the electrodeposition metal 6 are reliably integrally joined by plating. be able to.

  According to the second aspect of the present invention, the mask thicknesses of both the region A having a high aperture density and the region B having a low aperture density can be made equal, and the mesh 5 is uniformly adhered and polymerized on the electrodeposited metal 6. It is the same as that of the first aspect of the invention. While the patterned resist film 11 remains in the opening of the electrodeposited metal 6 and the removed portion of the discarded electrodeposited metal 14 is filled with the liquid resist 19, the mesh 5 is adhered and polymerized thereon, so that the mesh 5 is electrically charged. Adhesion polymerization can be performed on the surface of the electrodeposited metal 6 without locally falling into the opening of the electrodeposited metal 6 or the removed portion of the electrodeposited metal 14. Further, there is no inconvenience that a plating film is formed in the opening of the electrodeposited metal 6 during plating and the opening width is narrowed. Even when the discarded electrodeposited metal 14 is scattered at many locations on the electroforming mold 10, it can be easily and efficiently removed by etching.

  According to the first aspect of the present invention, the metal mask having both the high opening density area A and the low opening density area B is also uniformly adjusted by devising the resist pattern. be able to. Therefore, when printing is performed using this metal mask, the overall printing thickness can be made uniform. In addition, the mesh 5 can be uniformly adhered and polymerized on the electrodeposited metal 6 having a substantially uniform overall mask thickness and the same height. The mesh 5 and the electrodeposited metal 6 are partially floated or have poor adhesion. Can be reliably joined together by plating.

  According to the second aspect of the present invention, the mask thicknesses of both the region A having a high opening density and the region B having a low opening density can be adjusted uniformly, and the mesh 5 can be uniformly formed on the electrodeposited metal 6. The effect that it can be closely polymerized is obtained in the same manner as in the first aspect of the invention. Furthermore, even when the discarded electrodeposited metal 14 is scattered at many locations on the electroforming mold 10, it can be easily and efficiently removed by etching.

  (Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a mesh-integrated metal mask 1 obtained by the present invention has a plate on one side of a mask substrate 3 having a large number of openings 2 patterned in a desired printing pattern by electroforming. A conductive mesh 5 stretched in a tensioned state with respect to the frame 4 is closely polymerized and integrally joined by plating. Examples of the conductive mesh 5 include a type in which stainless steel fine wires are knitted, a type in which nickel plating is applied to the surface in which synthetic fibers such as polytetrafluoroethylene are knitted, or nickel or copper. A type in which a mesh is directly formed by electroforming is used. FIG. 1 shows a metal mask having a difference in density in aperture density. That is, in the metal mask, a plurality of minute columnar electrodeposited metals 6 exist in the form of solitary islands in a relatively large opening 2 to increase the opening density, and an opening 2 smaller than that. , And a region B with a low aperture density arranged sparsely, but the mask thickness is uniform throughout.

  Therefore, for example, when screen printing is performed using the mesh-integrated metal mask 1, the surface of the mask substrate 3 opposite to the mesh 5 is brought into close contact with a printed object such as a wiring substrate, and the solder paste is applied to the mesh 5 A squeegee is placed on the surface of the sheet and discharged from the opening 2 to transfer and adhere to the printing object. At this time, the solder paste film thickness (printing thickness) can be uniformly transferred and attached to the printing object.

  2A is a cross-sectional plan view of a patterned resist film formed so as to correspond to the electroforming of a part of the metal mask, and FIG. 2B is a crossing showing a part of the metal mask immediately after electroforming. It is a top view. FIGS. 3A to 3G show process diagrams for obtaining such a metal mask by electroforming. First, as shown in FIGS. 2 (A) and 3 (A), an opening corresponding to the rib-like electrodeposited metal 6 portion of the metal mask 1 is formed on the surface of a conductive electroforming mother die 10 such as stainless steel. A pattern resist film 11 having a pattern corresponding to the opening 2 of the metal mask 1 is formed. At that time, the electrodeposited metal 6 in the region A is applied to the pattern resist film 11 corresponding to the opening A 2 having a high opening density, for example, in this embodiment, the minute columnar electrodeposited metal 6 arranged in an island shape. A plurality of isolated electrodeposition openings 12 for electrodeposition for adjusting the amount of electrodeposition is formed. As is well known, the pattern resist film 11 having the opening 9 and the discarded electrodeposition opening 12 is laminated with a film-like photoresist having a thickness of 200 to 300 μm, for example, on the surface of the electroformed mother die 10. A printed pattern film in which a predetermined pattern is formed on a resist is brought into intimate contact with each other and subjected to exposure, development and drying.

  Next, with the pattern resist film 11 attached, the electroforming mother die 10 is moved to the electrodeposition bath as a cathode, and electroforming of nickel, nickel-cobalt alloy or the like is performed, and FIG. 2 (B) and FIG. The electrodeposit metal 6 corresponding to the mask substrate 3 is formed on the surface corresponding to the opening 9 not covered with the pattern resist film 11 of the electroforming mother mold 10 as shown in FIG. A discarded electrodeposition metal 14 is formed.

  After electroforming, the surface is polished and smoothed, or without polishing, as shown in FIG. 3C, on the surfaces of the electrodeposited metal 6, the discarded electrodeposited metal 14 and the pattern resist film 11, A film-like etching resist 15 is laminated, or a liquid etching resist 15 is applied and dried, and the etching resist 15 is cured on the etching resist 15 except for a portion corresponding to the pattern of the discarded electrodeposited metal 14. An etching resist film 17 that masks the surface other than the discarded electrodeposition metal 14 as shown in FIG. Form. Next, by etching with an etching solution such as ferric chloride, all of the discarded electrodeposition metal 14 is removed or left in a state of leaving a little on the surface of the electroformed mother die 10 as shown in FIG.

  Next, as shown in FIG. 3 (F), the etching resist film 17 is peeled off, and a liquid resist 19 is filled up to the same height as the pattern resist film 11 in the recessed portion from which the discarded electrodeposited metal 14 has been removed. Let Thus, the conductive mesh 5 is pressed onto the surface of the electrodeposited metal 6, the pattern resist film 11, and the cured liquid resist 19, and adhesion polymerization is performed. Next, plating such as nickel plating is applied from the direction of the mesh 5. By this plating, a plating film 20 is formed on the mesh 5 as shown in the enlarged view in FIG. 3G, and the electrodeposited metal 6 and the mesh 5 are integrally joined. In addition, although the thickness of the plating film 20 is arbitrarily adjusted, for example, the thickness is set to about 3 to 5 μm. As shown in FIG. 1, the mesh 5 is formed by tensioning a mesh made of a fine stainless steel wire or an electroformed mesh on the plate frame 4 in a tensioned state. However, it is desirable to pre-treat the mesh 5 by electrolytic pickling (cathodic pickling) in order to improve the adhesion of the plating before plating.

  Finally, the electrodeposited metal 6 is peeled off from the electroforming mother mold 10 together with the mesh 5, and if the pattern resist film 11 or the liquid resist 19 adheres to the electrodeposited metal 6 side, these are removed with an alkaline solution or the like. As a result, a mesh-integrated metal mask electroformed product as shown in FIG. 3 (G) and FIG. 1 is obtained. In addition, there is no problem because the discarded electrodeposited metal 14 that remains a little remains on the surface of the electroformed mother die 10 at the time of peeling.

  (Embodiment 2) FIG. 4 shows a second embodiment, wherein (A) is a cross-sectional plan view of a patterned resist film formed so as to correspond to electroforming of a part of a mesh-integrated metal mask, (B). FIG. 3 is a cross-sectional plan view showing a part of the metal mask immediately after electroforming. In this embodiment, as shown in FIG. 4B, a region A in which a large number of independent openings 2 are densely gathered at a small pitch on the continuous rib-shaped electrodeposited metal 6 of the metal mask, and the opening density is increased. An embodiment in the case of manufacturing a mesh-integrated metal mask having both regions 2 sparsely arranged and a region B in which the opening density is lowered will be described. In this case, as shown in FIG. 4 (A), a large number of independent draining openings 12 are provided at locations corresponding to the region A of the pattern resist film 11, and the power is applied as shown in FIG. 4 (B). A continuous rib-like electrodeposited metal 6 is formed at the time of casting, and at the same time, an isolated electrodeposited portion 14 is formed in a large number of independent openings 2 of the electrodeposited metal 6. Thereby, the mask thickness of the region A with a high aperture density and the mask thickness of the region B with a low aperture density can be adjusted equally. Other than that, it carries out similarly to the case of 1st Example.

  (Example 3) When the discarded electrodeposited metal 14 can be continuously formed as shown in FIG. 5A, it is manually replaced as shown in FIG. It can also be peeled off. In this case, the opening formed after the discarded electrodeposited metal 14 is peeled off is filled with the liquid resist 19 in the same manner as in the above embodiment, and then the electrodeposited metal 6 and the mesh 5 are integrated by plating.

It is a perspective view of the mesh-integrated metal mask of the first embodiment. (A) is a cross-sectional plan view of a patterned resist film formed so as to correspond to the electroforming of a part of the metal mask shown in FIG. 1, and (B) is a cross-sectional plane showing a part of the metal mask immediately after electroforming. FIG. It is a manufacturing-process figure of the mesh integrated type metal mask of 1st Example. A second embodiment is shown, in which (A) is a cross-sectional plan view of a patterned resist film formed so as to correspond to electroforming of a part of a mesh-integrated metal mask, and (B) is a part of the metal mask. It is a cross-sectional top view shown in the state immediately after electroforming. A third embodiment is shown, (A) is a cross-sectional plan view showing a part of a mesh-integrated metal mask immediately after electroforming, and (B) is a state in which a discarded electrodeposited metal is manually peeled off. FIG. 6 is a cross-sectional view taken along line XX in FIG. FIG. 6A shows a conventional example, FIG. 6A is a cross-sectional plan view showing a part of a mesh-integrated metal mask with the mesh removed, and FIG. 6B is a state where the mesh is integrated, Y in FIG. It is sectional drawing of a -Y line. The other conventional example is shown, (A) is a cross-sectional plan view showing a part of a mesh-integrated metal mask with the mesh removed, and (B) is a part of the metal mask shown with the mesh integrated. It is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal mask 3 Mask substrate 4 Plate frame 5 Mesh 10 Electroforming mother mold 11 Pattern resist film 12 Discarding electrodeposition opening 14 Discarding electrodeposition metal 17 Etching resist film 19 Liquid resist

Claims (2)

A pattern resist film 11 corresponding to each pattern of a region A having a high opening density, a region B having a low opening density, and a discarded electrodeposition opening 12 disposed in the region A on the surface of the electroforming mother die 10. Forming a pattern,
Forming an electrodeposition metal 6 corresponding to the mask substrate 3 and a discarded electrodeposition metal 14 for adjusting the mask thickness on the surface of the electroforming mother die 10 not covered with the pattern resist film 11;
A step of removing the discarded electrodeposited metal 14 after electroforming;
On the surface of the electrodeposited metal 6 and the pattern resist film 11, a step of closely polymerizing the conductive mesh 5;
A step of integrally joining the mesh 5 and the electrodeposited metal 6 by plating;
A method for producing a mesh-integrated metal mask, comprising the step of peeling the electrodeposited metal 6 together with the mesh 5 from the electroformed mother die 10. A pattern resist film 11 corresponding to each pattern of a region A having a high opening density, a region B having a low opening density, and a discarded electrodeposition opening 12 disposed in the region A on the surface of the electroforming mother die 10. Forming a step;
Forming an electrodeposition metal 6 corresponding to the mask substrate 3 and a discarded electrodeposition metal 14 for adjusting the mask thickness on the surface of the electroforming mother die 10 not covered with the pattern resist film 11;
Etching with an etching resist film 17 that masks the surface other than the discarded electrodeposited metal 14 on the surface of the electrodeposited metal 6, the discarded electrodeposited metal 14 and the pattern resist film 11 is performed. Removing, and
A step of filling and removing the liquid resist 19 to the same height as the pattern resist film 11 in the removed portion of the discarded electrodeposition metal 14;
A step of closely polymerizing the conductive mesh 5 on the surface of the electrodeposited metal 6, the pattern resist film 11 and the cured liquid resist 19,
A step of integrally joining the mesh 5 and the electrodeposited metal 6 by plating;
A method for producing a mesh-integrated metal mask, comprising the step of peeling the electrodeposited metal 6 together with the mesh 5 from the electroformed mother die 10.

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