JPH09239954A - Combination mask attaching structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal mask attaching structure making a metal mask and a frame easily detachable, applying elasticity and constant tension to the whole surface of the metal mask to form flatness and capable of obtaining the close adhesiveness to a base plate. SOLUTION: The entire periphery of the end part of the screen integrated with the metal mask 1A of a combination mask is superposed on a frame 5A and held between the holding groove 153 and fixing metal fitting 7 provided to the frame 5A by utilizing the elasticity of the screen 34 to apply tension to the entire surface of the metal mask 1A. Further, by regulating the expansion quantity of the rubber tube 10 provided in the fixing metal fitting 7, the screen 3A is pressed o the inside surface of the holding groove 153 of the fixing metal fitting 7 of each side to be fixed to the frame 5A and predetermined tension is applied to the entire surface of the metal mask 1A to form flatness to obtain the close adhesiveness to a base plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure in which a metal mask used for printing a solder paste is attached to a frame on a printed circuit board or a hybrid IC substrate (hereinafter abbreviated as substrate).

[0002]

2. Description of the Related Art The conventional method of soldering surface-mounted components is to attach a metal mask having a hole of an appropriate shape at a position corresponding to the land of a mounted component such as a substrate, and then to the land. After solder paste is printed using a squeegee and mounting components are mounted, heating is performed in a heating furnace to melt the solder, thereby performing soldering. The metal mask used for solder paste printing has a thickness of 0.2 m.
It is made of a stainless steel or nickel thin plate having a thickness of about m to 0.12 mm, and the holes are formed by an etching method or an additive method. In the printing method using a metal mask, a solder paste is printed with a squeegee while the metal mask is in close contact with a substrate or the like. In order to bring the metal mask into close contact with the substrate or the like, it is necessary to eliminate the bending of the metal mask itself and improve the flatness. For this reason, commonly known combination masks are often used in which tension is obtained by adhering a screen around the metal mask to improve adhesion. 3 is a plan view showing the combination mask, and FIG. 4 is a cross-sectional perspective view of a portion AA of FIG. A screen 3B is provided between the metal mask 1B and the frame 5B.
Is provided, and they are fixed by the screen adhesive portion 12,
Utilizing the elasticity of the screen 3B, tension is applied to the entire metal mask 1B to maintain the flatness and improve the adhesion to the substrate or the like.

The method of attaching the metal mask 1B of this combination mask to the frame 5B is as follows.
The periphery of B is overlapped with the periphery of the central opening 4 of the screen 3B stretched with a constant tension, and is bonded with an epoxy adhesive,
Next, while applying a constant tension, the entire circumference of the screen 3B is bonded to the frame adhesive portion 13 with an epoxy adhesive, and the screen 3B protruding from the frame 5B is cut along the outer periphery of the frame 5B. However, in the combination mask, since the metal mask 1B, the screen 3B and the frame 5B are integrated, a large number of combination masks must be manufactured for each type of substrate and the like, which not only increases the cost but also increases the frame. Since the thickness is 30 to 50 mm, there is a problem that the storage space becomes large. Further, until now, a halogen-based solvent such as trichloroethane has been used as a solvent for a metal mask cleaning machine.
Since the production was discontinued at the end of 5 years, glycol ether solvents are widely used as alternative solvents. Compared with trichloroethane type solvent, the drying property of the solvent is poor, so
The phenomenon that the solvent remains on the bonding portion of the combination mask, particularly the frame bonding portion 13 of the frame 5B and the screen 3B and is eroded and peeled off frequently, has recently caused a new problem that the screen 3B needs to be reattached. There is.

In order to solve the above problems, in recent years, a method has been considered in which the metal mask and the frame are detachable and the metal mask is attached by applying tension. FIG.
5 is a plan view showing a mounting structure described in Japanese Patent Application Laid-Open No. 7-71027, which is a conventional example, and FIG.
It is a cross-sectional perspective view of the AA part of. Metal mask 1C 1
The pin holes 14 are formed on opposite sides of the set, and a large number of support pins 16 are inserted into the pin holes 14 of the metal mask 1C in the holding metal fitting 151 having a width sufficiently larger than the size of the metal mask, and the pulling metal fittings 17 are used. The tension can be changed by the tension nut 18, and the metal mask 1C can be attached and detached. FIG. 7 is a plan view of an embodiment described in Japanese Patent Laid-Open No. 7-3823, and FIG. 8 is a sectional perspective view of a portion AA of FIG. The holding portions 152 integrally extending from the opposite sides of the metal mask 1D are provided, and a large number of punched holes 19 are formed in the holding portion width direction, so that the elasticity of the metal mask itself is held. Also, this holding portion 15
The supporting plate 24 is sandwiched between the bent portions 20 provided at the end portions of the two, and a plurality of places are connected by the fixing screws 23. Next, the support plate 24 to which the bent portion 20 is fixed is inserted into the holding groove 21 provided in the frame 5D, and tension is applied by the tension screw 22 from the outer surface of the frame 5D. Further, the guide plate 25 is inserted into the wide groove 27 from the lower surface of the frame 5D and attached to the support plate 24 with the screw 23, and the guide plate 25 is brought into contact with and fixed to the upper surface of the wide groove 27. In this way, the metal mask is attached to the frame by making it attachable and detachable with a large number of screws.

[0005]

In the embodiment shown in FIG. 5, in which the metal mask and the frame are detachable, tension is applied by pulling a pair of opposite sides of the metal mask in opposite directions by the holding metal fittings. However, since only one pair of opposite sides is pulled, tension is applied only to the central part of the metal mask, the metal mask on the other opposite side bends, and the metal mask is directly attached to the frame through the pulling metal fittings. Since it is mounted, there is no elasticity obtained by the combination mask, and flatness cannot be obtained because a constant tension cannot be applied to the entire surface of the metal mask, and there is a problem that adhesion to the substrate cannot be expected. In the method disclosed in Japanese Patent Laid-Open No. 7-3823 of FIG. 7, in order to maintain the tension of the metal mask, it is necessary to attach each side of the frame with a large number of screws, which complicates the replaceability of the metal mask. In addition, there is a drawback that it takes setup steps. Therefore, in the present invention, the metal mask and the frame can be easily attached and detached,
It is another object of the present invention to provide a metal mask mounting structure which is elastic and has a certain tension applied to the entire surface of the metal mask to form planarity and which can obtain adhesion to the substrate.

[0006]

In order to achieve the above-mentioned object, the present invention has an initial state in which a screen portion integrated with a metal mask of a combination mask conventionally used is separated from a frame, and the screen end portion is Tension is applied to the entire surface of the metal mask by superimposing the entire circumference on the frame and sandwiching it by the holding groove and the fixing metal fitting provided in the frame by utilizing the elasticity of the screen. Furthermore, by adjusting the amount of expansion of the rubber tube provided in the fixing bracket, the screen is pressed against the inner surface of the holding groove of the fixing bracket on each side and fixed to the frame, while a predetermined tension is applied to the entire surface of the metal mask. In addition, flatness is formed so that adhesion to the substrate can be obtained. As described above, according to the present invention, since the metal mask and the frame can be easily attached and detached and the elasticity of the screen is used to obtain the tension, the flatness of the metal mask is formed and the adhesion to the substrate can be obtained. To In addition, since the frame can be shared, it can be stored only by the thin metal mask and the screen which are integrated, so that the storage space can be remarkably reduced as compared with the conventional case.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be specifically described below with reference to FIGS. 1 is a plan view showing an embodiment of a metal mask of the present invention, and FIG. 2 is a sectional perspective view of a portion AA of FIG. The metal mask 1A is made of stainless steel or a nickel thin plate, 2 is a hole provided in the metal mask corresponding to the land of the surface mount component, 3
A is a screen stretched from the periphery of the metal mask 1A with a constant tension, and 12 is a screen bonding portion in which the metal mask 1A and the screen 3A are bonded with an epoxy adhesive. In addition, in one embodiment of the present invention, the metal mask 1
The structure of the screen bonding portion 12 in which A and the screen 3A are combined is similar to the conventional case shown in FIG.
The outer circumference of the screen 3A is one size larger than the frame 5A. Further, the conventional screen 3B and metal mask 1B may be separated from the frame 5B and used again. When the conventional one is used, the frame 5A used is slightly smaller than the outer circumference of the screen 3B.

A structure in which the metal mask 1A is detachably attached to the frame 5A will be specifically described with reference to FIG.
Here, 153 is a holding groove provided in the frame 5A, and 7 and 8 are fixing metal fittings for holding the screen 3A in the holding groove 153 of the frame 5A. The fixing metal fitting 7 is connected all around, and the fixing metal fitting 8 is , Provided separately on each side and connected to the fixing metal fitting 7 by the connecting pin 9. The connecting pin 9 is the fixing metal fitting 8
The holding groove 153 is structured to be movable in the inner side surface direction. Further, the fixing brackets 7 and 8 are the tube 1
It has a structure that 0 is enclosed all around, and the air injection part 11
By injecting air into the tube 10, the tube 10 expands, the fixing fittings 8 on the respective sides are pressed against the inner surface of the holding groove 153, and the fixing fittings 7 and 8 are fixed so as not to come out of the holding groove 153. . Metal mask 1A frame 5A
When it is attached to the metal mask 1A, the entire circumference of the end of the screen 3A integrated with the metal mask 1A is sandwiched by pressing the fixing metal fittings 7 and 8 against the bottom surface of the holding groove 153 of the frame 5A. This time,
The fixing fittings 7 and 8 pull the fixing fittings 8 on the respective sides toward the 7 side so that the fixing fittings 7 and 8 can be inserted into the holding groove 153.
Insert

After that, the tube 10 in the fixing fittings 7 and 8
By injecting air into the tube 10, the tube 10 expands, the fixing fittings 8 on each side are pressed against the inner surface of the holding groove 153 and fixed, and at the same time, the fixing fitting 8 moves to the inner surface of the holding groove. , The screen 3A is pulled in the outer circumferential direction, a constant tension is applied to the entire surface of the metal mask 1A, and the flatness is obtained by eliminating the deflection. In addition,
Injecting air into the tube 10 uses a control valve in its path.
(Not shown) is provided, and the tension can be changed by the opening / closing degree of this valve. When removing the metal mask 1A attached to the frame 5A, the air injecting section 1
By removing the air from 1 and pulling the screen 3A protruding from the outside of the fixing metal fitting 7 in the upward direction, the fixing metal fitting 8 can be pulled toward the 7 side and easily removed from the holding groove 153. Further, when the screen 3A is sandwiched by the fixing metal fittings 7 and 8, the screen 3A concentrates on the corner portion of the frame 5A, and the screen may be damaged. However, the cutting groove provided in the corner portion of the holding groove 153 on the surface in contact with the fixing metal fitting 8 is considered. The notch portion 51A and the notch portion 71 provided at the corner portion of the fixing bracket 7 can prevent the screen 3A from being damaged. In the above embodiment, the tube 10
Although air is injected into the above, the present invention is not limited to this, and other gas or liquid such as liquid can be used.

[0010]

As described above, in the structure for attaching the metal mask to the frame according to the present invention, the metal mask integrated with the screen is used. When the metal mask is attached to the frame, the elasticity of the screen acts to apply tension to the entire surface of the metal mask. It is possible to obtain flatness and adhesion to the substrate. Further, in the structure in which the entire circumference of the end portion of the screen portion integrated with the metal mask according to the present invention is detachably clamped by the holding groove of the frame and the fixing metal fittings, the screen is pulled in the outer circumferential direction and tension is applied to the entire surface of the metal mask. Is added. Furthermore, the tube inside the fixing bracket expands,
The fixing metal fitting is pressed against the inner surface of the holding groove to be fixed to the frame, and the amount of movement of the fixing metal fitting to the inner surface of the holding groove causes the screen to be pulled in the outer circumferential direction and a constant tension is applied to the entire surface of the metal mask. Deflection of the metal mask can be eliminated, flatness can be maintained, and adhesion to the substrate can be improved. In addition, since the entire circumference of the screen is clamped by the fixing brackets, the tube inside the fixing brackets can be expanded, fixed to the frame and held by applying tension, so screws are used when attaching to the frame. It can be installed without it, and the metal mask can be easily replaced. Further, since the frame can be shared, it is not necessary to manufacture a large number of metal masks for each type of substrate, and the cost can be reduced. In addition, since the frame is shared and the metal mask is sandwiched, it can be stored only with the thin metal mask and the screen which are integrated, which is effective in reducing the storage space.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment showing a mounting structure of a metal mask of the present invention.

FIG. 2 is an enlarged sectional perspective view taken along the line AA of FIG.

FIG. 3 is a plan view of a conventional combination mask.

FIG. 4 is an enlarged sectional perspective view taken along the line AA of FIG.

FIG. 5 is a plan view of an embodiment showing a conventional metal mask mounting structure.

6 is an enlarged cross-sectional perspective view taken along the line AA of FIG.

FIG. 7 is a plan view of a second embodiment showing a conventional metal mask mounting structure.

8 is an enlarged sectional perspective view taken along the line AA of FIG.

[Explanation of symbols]

1A: Metal mask, 2: Pattern hole, 3A: Screen, 12: Screen adhesion part, 5A: Frame, 7,8: Fixing metal fitting, 9: Connection pin, 10: Tube, 11: Air injection part, 153: Holding groove , 51A, 71: Notch.

Claims (2)

[Claims] 1. When attaching a combination mask in which a metal mask and a screen are integrated to a frame, a holding groove is provided on all sides of the frame, and the holding groove is fitted into the holding groove so that the entire circumference of an end portion of the combination mask is concerned. A combination mask attachment structure characterized in that the combination mask is detachably attached to the frame by using a fixing metal fitting that is pressed against the inner surface of the holding groove and clamped. 2. The fixing metal fitting according to claim 1, wherein the fixing metal fitting has an inner metal fitting and an outer metal fitting that contain a tube that expands when a fluid is injected, and the inner metal fitting in the holding groove is expanded by the expansion of the tube. A structure for moving a combination mask, wherein the combination mask is attached to the frame with uniform tension.