JPH11263081A - Metal mask and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metal mask having a recess space covering a protrusion on a printed surface of a printed matter with small unevenness of a thickness of a mask plate having printing pores for passing paste-like ink and small process strain. SOLUTION: The metal mask comprises a plate-like mask plate 1 having printing pores 4 provided corresponding to a pattern to be printed with paste- like ink on a printing surface of a printed matter and a protrusion passing hole 2 provided corresponding to a protrusion provided on the printing surface of the matter, and a cover 5 formed in a container shape opened at a lower surface. An edge of a periphery of an opening of the cover 5 is fixed to a periphery of the hole 2 of the plate 1 to be mounted on the plate 1. Another cover 5 previously formed is mounted on the plate 1 to form a recess covering the hole 2, and hence an unevenness in a thickness and a process strain are scarcely formed at the plate 1 having the pores 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal mask having printing holes through which paste-like ink can pass, for printing a paste-like ink such as a solder paste on a printed surface of a printed wiring board, and a method of manufacturing the same. In particular, the present invention relates to a metal mask capable of printing paste ink in a state in which a protrusion such as a circuit component is mounted on a printing surface of a printed wiring board in advance.

[0002]

2. Description of the Related Art When soldering a circuit component such as a chip-shaped circuit component to an electrode formed on a printed wiring board, a solder paste is printed on a land electrode on the printed wiring board, and then a land on the printed wiring board is printed. 2. Description of the Related Art A circuit component is mounted at a position corresponding to an electrode, a solder paste is reflowed while being temporarily fixed with an adhesive or the like, and then the reflowed solder is cured to solder the circuit component.

In printing the above-mentioned solder paste on a printed surface of a printed material such as a printed wiring board, a metal mask has been conventionally used. The metal mask is made of a thin plate of stainless steel or the like, and has printing holes corresponding to positions where paste-like ink such as solder paste is to be printed on a printed material such as a printed wiring board.
This metal mask is placed on the printing surface of the printed matter, and paste-like ink is applied on the metal mask, and the paste is thinly stretched with a squeegee to fill the printing holes with the paste-like ink. Thereafter, by removing the metal mask from the printed surface of the printed matter, the paste ink is printed at a predetermined position on the printed surface.

When a circuit device is manufactured by mounting and soldering circuit components on a printed wiring board, it is necessary to go through several printing steps. In the solder paste printing step, there is also a step of printing solder paste on land electrodes on the printed wiring board in order to mount another circuit component in a state where the circuit components are already mounted on the printed wiring board.
In such a case, in order to avoid circuit components already mounted on the printed wiring board, a metal mask having a concave space on the lower surface is used (for example, Japanese Utility Model Application Laid-Open No. 63-1).
No. 06664). In order to avoid a circuit component already mounted on such a printed wiring board, as a means for manufacturing a metal mask having a concave space on the lower surface, conventionally, means for forming a concave portion by plastically processing a metal plate by pressing. Alternatively, a method of forming a metal mask having a concave portion by forming a replica-shaped plating film by electroforming is employed (for example, Japanese Patent Application Laid-Open No. Hei 6-31890).

[0005]

As described above, in the metal mask manufacturing means for forming a concave space on the lower surface by plastic working, when a part of the metal mask for forming the concave portion is plastically deformed, Processing distortion also extends around the concave portion of the metal mask. Due to the processing distortion, the accuracy of the position and shape of the printing hole for printing the solder paste is deteriorated.
Therefore, it is not suitable for printing a solder paste or the like on a fine printed wiring board. In the means of manufacturing a metal mask by electroforming, there is no problem of processing distortion, but through steps such as machining of a master metal, printing and plating of a photoresist, removal of a photoresist, plating, and further stripping of a plating film. Required, and it takes a lot of trouble to manufacture. Moreover, the thickness of the obtained metal mask tends to vary.

The present invention has been made in view of the above-mentioned problems of the conventional metal mask manufacturing technology. Therefore, the present invention provides a concave space in which a variation in plate thickness and processing distortion are small and which can cover a protrusion on a printing surface of a printed material. To obtain a metal mask having the same. Moreover, it is an object of the present invention to easily obtain the metal mask.

[0007]

According to the present invention, in order to achieve this object, a printing hole 4 for passing a paste-like ink such as a solder paste and a circuit component such as a circuit component already mounted on a printing surface of a printed matter b are provided. Separately from the plate-shaped mask plate 1 provided with the projecting object passage hole 2 corresponding to the projecting object a, a container-shaped cover 5 having an opening at the bottom is made. Attachment, the periphery of the cover 5 is fixed to the periphery of the projecting object passage hole 2 by welding or the like, and sealed. Here, the internal space of the cover 5 provided so as to cover the projection passing hole 2 is a recess that avoids the projection a on the printing surface.

That is, the metal mask according to the present invention comprises:
In the metal mask having the printing holes 4 for printing the paste-like ink on the printing surface of the printed matter b, the printing holes 4 are provided corresponding to the pattern for printing the paste-like ink on the printing surface of the printed matter b. A mask plate 1 having a plate-like mask plate 1 provided with a projecting object passage hole 2 corresponding to the projecting object a provided on the printing surface of the above, and a cover 5 formed in a container shape having an open lower surface. The edge around the opening of the cover 5 is fixed to the periphery of the projection passing hole 2 of the mask plate 1.

In order to manufacture such a metal mask, first, the printing holes 4 corresponding to the positions where the paste ink is to be printed on the printing surface of the printed material a of the plate-shaped mask plate 1.
Then, the protrusion passing hole 2 corresponding to the protrusion a provided on the printing surface of the print b of the mask plate 1 is formed. In addition, a cover 5 formed in a container shape having an open lower surface is formed, and an edge around the opening of the cover 5 is fixed around the projecting object passage hole 2 of the mask plate 1. The step of forming the printing holes 4 and the projecting object passing holes 2 in the mask plate 1 can be performed by laser processing.

In such a metal mask, the mask plate 1
By attaching a separate cover 5 made in advance, a concave portion covering the projecting object passage hole 2 can be formed.
Variations in plate thickness and processing distortion hardly occur in the mask plate 1 having the printing holes 4. Therefore, the precision of the printing holes 4 provided according to the design can be maintained without causing the printing holes 4 to shift or deform due to the formation of the concave portions. For example, the cover 5 can be attached by laser welding the periphery of the opening to the periphery of the projecting object passage hole 2 of the mask plate 1, and the attachment of the cover 5 is easy. Further, by sealing the joint between the cover 5 and the mask plate 1 with the sealing material 8, a metal mask free from leakage of the paste-like ink can be obtained.

When the cover 5 and the mask plate 1 have positioning means for positioning the projecting object passage hole 2 of the mask plate 1 and the opening on the lower surface of the cover 5, the cover 5 is positioned with respect to the projecting object passage hole 2. Can be mounted in the correct position. As such a positioning means, an insertion piece 7 protruding from an edge around the opening of the cover 5 and the insertion piece 7 corresponding to the position of the insertion piece 2 of the mask plate 1 are provided. And a combination with the engaging portions 3 and 3 ′ that are provided around the peripheral portion and are engaged with the insertion piece 7. Engaging part 3 of mask plate 1
In general, a through-hole into which the insertion piece 7 of the cover 5 is fitted is formed, but an engaging portion 3 ′ formed of a concave portion provided on the inner periphery of the protrusion passing hole 2 is formed. May be fitted.

The cover 5 may be formed by plastic working such as pressing or the like. However, a plate-shaped material 10 having a predetermined shape is cut out by means of laser processing or the like, and the plate-shaped material 10 is bent to form a container. Can be manufactured more easily. Plate material 10 forming this cover 5
Has a notch 13 at the position where it is bent,
Easy to bend. The cut 13 can be prevented from leaking the paste ink by bending the plate material 10 along the cut 13 and then sealing the cut material 13 with the seal member 9.

The cover 5 is formed by plastic working such as pressing.
When molding the cover, a crack generated in the bent portion 14 of the cover 5 may be sealed by laser welding. By laser welding cracks in the bent portion 14 of the cover 5 before and after laser welding the periphery of the opening of the cover 5 around the protruding object passage hole 2 of the mask plate 1, the cover can be covered only by laser welding. 5 attachments are possible. By taking such means, the plate member 10 for forming the cover 5 is cut out, the protruding object passage holes 2 of the mask plate 1 are punched, and the cover 5 is formed.
Of the cover 5 around the protrusion passing hole 2 and the bent portion 1 of the cover 5
The sealing of the cracks generated in 4 can be performed by laser processing, and the manufacture of the metal mask can be performed by a single means called laser processing.

[0014]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 is an exploded view of an example of a metal mask according to the present invention. As shown in FIG. 1, the metal mask includes a mask plate 1 and a cover 5. The mask plate 1 is made of a thin metal plate such as stainless steel, and the mask plate 1 is provided with printing holes 4 through which paste-like ink such as solder paste is passed according to a predetermined printing pattern.
That is, the printing holes 4 are formed at positions where the solder paste is to be printed on the printed wiring board.

Further, the mask plate 1 is provided with a projecting object passage hole 2 in order to avoid a projecting object on a printed surface of a printed material such as a printed wiring board. This protrusion passing hole 2
Are provided corresponding to the positions of the protrusions on the printed surface of the printed matter, such as a printed wiring board, and are perforated larger than the projection surface of the protrusions on the printed surface. In the example of FIG. 1, a square projecting object passage hole 2 is formed substantially at the center of the mask plate 1.

A through hole is formed around the protrusion passing hole 2 as an engaging portion 3 serving as a positioning means so as to surround the protrusion passing hole 2. The engaging portion 3 is perforated at a position and a shape corresponding to the insertion piece 7 provided at an opening edge of the cover 5 described later. The printing hole 4 and the protrusion passing hole 2 described above.
It is appropriate that the engaging portion 3 is perforated by means such as laser processing or etching.

On the other hand, the cover 5 is a container having an open bottom, and the cover 5 shown in FIG. 1 has a square plane and a trapezoidal side surface. The cover 5 accommodates and covers a projecting object such as a circuit component on a printing surface such as a printed wiring board. Therefore, the inner space of the cover 5 is formed wider than the protrusion. The lower edge of the periphery of the opening of the cover 5 is formed large by the projecting object passage hole 2 of the mask plate 1. An insertion piece 7 projects from a lower edge around the opening of the cover 5, and the insertion piece 7 has a size adapted to the engagement portion 3 of the mask plate 1. Also,
These insertion pieces 7 are arranged at positions that match the engagement portions 3 of the mask plate 1.

Such a cover 5 may be manufactured by punching a plate material with a press or the like for a circuit component or the like whose dimensions are standardized, and further drawing the punched plate material. However, in the manufacture of a metal mask that is rarely manufactured in large numbers, it is advantageous to cut out a plate-like material having a predetermined shape from a plate material by means of laser processing or the like and bend it. FIG. 3 shows an example of a plate material 10 cut out from a plate material by laser processing in a predetermined shape, which is a developed product of the cover 5 shown in FIG.

As shown in FIG. 3, in the plate-shaped material 10, elongated cuts 13 are arranged around a central square portion serving as the upper surface of the cover 5, and the portion serving as the upper surface of the cover 5 is
It is surrounded by these cuts 13. The cuts 13 are for making the plate-shaped material 10 bendable there, and are formed by laser processing or the like. The cut 13 may be an elongated slit-shaped opening as shown, or may be a groove-shaped one provided on the back surface of the plate-shaped material 10. V-shaped notches 12 are provided so as to open outward from the four corners of the plate-shaped material 10, that is, the vertices of the upper surface of the cover 5. Further, on four sides of the plate-shaped material 10, projections 11 serving as insertion pieces 7 of the cover 5 protrude.

The plate-shaped material 10 is cut into the cut 1
1 is bent along one side, a V-shaped notch 12 is fitted thereto, and joined by means such as laser welding or brazing or bonded with an adhesive or the like to assemble the cover 5 as shown in FIG. Can be The joining portion is sealed, and if the cut 13 is a slit-shaped through hole as shown in the figure, the portion is also sealed.

The cover 5 assembled from the plate material 10 in this manner is positioned from the state shown in FIG. 1 so as to cover the projecting object passage hole 2 of the mask plate 1, and further, the insertion piece of the cover 5 is inserted. 7 is aligned with the engaging portion 3 of the mask plate 1 and inserted. Similarly, the lower edge around the opening of the cover 5 abuts on a portion of the mask plate 1 around the projecting object passage hole 2. In this state, the projecting object passage hole 2 of the mask plate 1 is closed by the cover 5, and a concave space opened downward by the projecting object passage hole 2 is formed inside the cover 5. This state is shown in FIG.

The joint between the mask plate 1 and the cover 5 may be joined by means such as laser welding or brazing as necessary.
Alternatively, they are bonded with an adhesive. In addition, if necessary,
The joint is sealed with a sealing material 8 from the inside. Thus, a metal mask as shown in FIG. 2 is completed. FIG.
In the figure, reference numeral 9 denotes a sealing material that seals a portion of the cut 6 after bending, which is a slit, from the inside.

As shown in FIG. 4, such a metal mask is mounted on a printed surface of a printed material b such as a printed wiring board. Since the protrusion passing hole 2 and the cover 5 correspond to the position of the protrusion a such as a circuit component on the printed surface of the printed matter, the protrusion a fits into the cover 5 from the protrusion passing hole 2. Therefore, the mask plate 1 can be placed in close contact with the printing surface of the printed matter b. In this state, a paste-like ink such as a solder paste is applied to the mask plate 1 and spread on the mask plate 1 by a squeegee, so that the paste-like ink is applied to the printing holes 4 provided on the mask plate 1. Will be filled. At this time, since the protrusion a is covered with the cover 5, the paste ink does not adhere to the protrusion a. After that, when the mask plate 1 is separated from the printing surface of the printed material a, only the paste ink filled in the printing holes 4 remains on the printing surface of the printed material b, and the printing of the paste ink is completed. In FIG. 4, only the cover 5 is shown in an enlarged manner, but the paste ink and the squeegee are not shown.

FIG. 5 shows another example of the metal mask according to the present invention. In the above-mentioned example, the planar shapes of the projecting object passing holes 2 and the cover 5 provided in the mask plate 1 are square, but in this example, the planar shapes of the projecting object passing holes 2 and the cover 5 provided in the mask plate 1 are square. Is an octagon. Among the protruding parts a such as circuit components already mounted on the printed wiring board,
Some planes have a circular shape or a shape close thereto. In such a case, it is advantageous in terms of space if a protruding object passage hole 2 such as a plane octagon or a plane circular as shown in FIG. 5 is provided and a cover 5 corresponding to the shape is attached.

FIG. 6 shows an example of the shape of a plate material 10 for forming the cover 5 used for the metal mask shown in FIG. The plate-shaped material 10 shown in FIG. 5 has an octagon at the portion to be the upper surface of the cover 5 and has a regular octagon in the example of FIG. Of course, the shape may not be a regular octagon, but may be an unequal octagon. Surround the upper surface of the cover 5,
Elongated cuts 13 are arranged around the periphery. A V-shaped notch 12 is provided in the periphery of the plate-shaped material 10 so as to open outward from the position of the apex of a portion to be the upper surface of the cover 5. In the example of FIG. 5, since the upper surface of the cover 5 is a regular octagon, eight notches 12 are provided radially at equal angular intervals. Further, projections 11 serving as insertion pieces 7 of the cover 5 project from eight sides of the plate-shaped material 10.

This plate-shaped material 10 is also bent to one side along the cut 13 in the same manner as in
The cover 5 as shown in FIG. 5 is assembled by aligning the notches 12 in a letter shape and joining them by means such as laser welding or brazing, or by bonding them with an adhesive or the like.
Further, the joint and the cut 2 are sealed as required.

The cover 5 assembled from the plate-like material 10 in this manner is changed from the state shown in FIG. 5 to the engaging piece 3 of the mask plate 1 in the same manner as in the above-described example.
And is fitted so as to close the protruding object passage hole 2 of the mask plate 1. Then, if necessary, the joint between the cover 5 and the mask plate 1 is fixed by means such as laser welding or the like, and the joint or the cut 6 after bending is sealed. Thereby, the metal mask is completed. These points are exactly the same as the above-mentioned example. This metal mask can also be used in the same manner as in the above-described example without using the same method.

FIG. 7 shows a modification of the metal mask shown in FIG. In each of the examples shown in FIGS. 1 to 4 and the examples shown in FIGS. 5 and 6, the engaging portion 3 of the mask plate 1 is a through hole.
On the other hand, in the example shown in FIG. 7, the engaging portion 3 ′ of the mask plate 1 is formed of a notch-shaped concave portion integrated with the protrusion passing hole 2. The concave engaging portion 3 ′ is cut radially from the periphery of the protrusion passing hole 2 provided in the mask plate 1. The cover 5 is similar to that of the example shown in FIGS. 5 and 6 described above, and the cover 5 is attached to the mask plate 1 by inserting the insertion piece 7 of the cover 5 into the engaging portion 3 ′.
Other points are the same as those in the example shown in FIGS. 5 and 6 described above.

8 to 10 show other modified examples of the metal mask. As described above, when the cut-out plate material 10 is bent, a crack is generated in the bent portion 14 as shown in FIG. In addition, a gap is also generated at a joint 15 where the V-shaped notch 12 of the plate-shaped material 10 is joined. Therefore,
In this example, cracks generated in the bent portions 14 are laser-welded and sealed, and the gaps between the joints 15 of the V-shaped notches 12 of the plate-shaped material 10 are sealed by laser welding. Further, a groove-shaped engaging portion 3 "is provided around the protruding object passage hole 2 of the metal mask 1 corresponding to the opening edge 7 'of the cover 5, and the opening portion 7" of the cover 5 is provided in the engaging portion 3 ". ', And this part is laser welded and sealed. In this modified example, there is an advantage that the metal mask can be easily manufactured by attaching and sealing the cover 5 to the projecting object passage hole 2 only by cutting and welding by laser processing.

In the three examples described above, the planar shapes of the projecting object passage hole 2 and the cover 5 provided in the mask plate 1 are all polygons, but they may be circular or other shapes. In particular, when there are a plurality of protrusions on the printing surface of the printed matter b, and when the protrusions a are not individually covered with the cover 5, but are covered with the integral cover 5, a special shape according to the arrangement is adopted. In some cases, the protrusion passing hole 2 and the cover 5 are used. Also in this case, it goes without saying that the present invention can be basically carried out in the same manner as in each of the above examples.

[0031]

As described above, according to the present invention, in the mask plate 1 having the printing holes 4, a concave portion is formed which has a small thickness variation and processing distortion and which avoids the protrusion a on the printing surface of the printed material b. Therefore, a metal mask with good precision in the shape and position of the printing hole 4 can be obtained. Furthermore, even when a single product or a small amount of a metal mask is made, it can be easily manufactured using a laser processing technique such as laser cutting or laser welding.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of a metal mask according to the present invention.

FIG. 2 is a vertical sectional side view of a main part showing a periphery of a cover of the metal mask.

FIG. 3 is a development view showing an example of a plate-like material for forming a cover of the metal mask.

FIG. 4 is a vertical sectional side view of a main part of a periphery of a cover showing a use state of the metal mask.

FIG. 5 is an exploded perspective view showing another example of the metal mask according to the present invention.

FIG. 6 is a development view showing an example of a plate-like material for forming a cover of the metal mask.

FIG. 7 is an exploded perspective view showing another example of the metal mask according to the present invention.

FIG. 8 is an exploded perspective view showing another example of the metal mask according to the present invention.

FIG. 9 is a vertical sectional side view of a main part showing a periphery of a cover of the metal mask.

FIG. 10 is an essential part enlarged perspective view showing a state before laser welding of a bent portion and a joint portion of the metal mask.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mask plate 2 projecting object passage hole 3 mask plate engaging portion 3 ′ mask plate engaging portion 3 ″ mask plate engaging portion 4 mask plate printing hole 5 cover 6 cover cut 7 cover insert 8 Sealing material 9 Sealing member 10 Plate-shaped material 13 Cut-out of plate-shaped material 14 Bent part of cover 15 Joint part of cover a Printed matter b Printed matter

Claims (16)

[Claims] 1. A metal mask having a printing hole (4) for printing a paste-like ink on a printing surface of a printed matter (b) corresponds to a pattern for printing the paste-like ink on a printing surface of the printed matter (b). A plate-shaped mask plate (1) provided with a printing hole (4) and a projection passing hole (2) corresponding to the projection (a) provided on the printing surface of the printed matter (b). ) And a cover (5) formed in a container shape with an open lower surface, and an edge around the opening of the cover (5) is formed as a protruding object passage hole (2) of the mask plate (1).
A metal mask fixed to the periphery of the metal mask. 2. The metal mask according to claim 1, wherein the joint between the cover and the mask plate is sealed by a sealing material. 3. The method according to claim 1, wherein the periphery of the opening of the cover is laser-welded to the periphery of the projecting hole of the mask plate. Metal mask. 4. The cover (5) and the mask plate (1) have positioning means for positioning the projecting object passage hole (2) of the mask plate (1) and the opening on the lower surface of the cover (5). The metal mask according to claim 1, wherein: 5. An edge passing through the opening of the mask plate (1) corresponding to the position of the edge around the opening of the cover (5).
(3), (3 '), (3 ") provided around
The metal mask according to claim 1, wherein the metal mask is engaged with the metal mask. 6. The device according to claim 5, wherein the engaging portion of the mask plate comprises a through hole into which the insertion piece of the cover is fitted. Metal mask. 7. The engaging portion (3 ') of the mask plate (1) is provided on the inner periphery of the projecting object passage hole (2), and the insertion piece (7) of the cover (5) is fitted. The metal mask according to claim 5, comprising a concave portion. 8. The device according to claim 5, wherein the engaging portion of the mask plate comprises a groove into which the insert piece of the cover is engaged. Metal mask. 9. The cover (5) cuts out a plate-shaped material (10) having a predetermined shape from a plate material, and cuts the plate-shaped material (1).
The metal mask according to any one of claims 1 to 8, wherein the metal mask is formed in a container shape by bending 0). 10. A plate material (1) forming a cover (5).
The metal mask according to any one of claims 1 to 9, wherein (0) has a cut (13) at a position where the metal mask is bent. 11. The metal mask according to claim 10, wherein the cuts (13) are sealed by a sealing member (9) after the plate material (10) is bent along the cuts (13). 12. The metal mask according to claim 9, wherein the bent part and the joint part of the cover are sealed by laser welding. 13. A method of manufacturing a metal mask having a printing hole (4) for printing paste-like ink on a printing surface of a printed matter (b), wherein the paste-like ink is printed on a printing surface of the printed matter (b). Printing hole corresponding to position (4)
And a protrusion (a) provided on the printing surface of the printed matter (b)
Forming a cover (5) formed in a container shape having an open lower surface, and forming an edge around the opening of the cover (5). Fixing to the periphery of the projecting object passage hole (2) of the mask plate (1). 14. The method according to claim 13, wherein the step of forming the printing holes (4) and the protrusion passing holes (2) in the mask plate (1) is performed by laser processing. Method. 15. The method according to claim 13, wherein the cover is made of a plate material cut out by laser processing. 16. The method for manufacturing a metal mask according to claim 13, wherein the bent part and the joint part of the cover are sealed by laser welding.