JPH0588973U - Screen for cream solder application - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a cream solder coating screen suitable for high-density mounting in which the amount of solder protruding from the land is small. [Structure] For one of the lands 4 provided on the substrate 3,
A configuration in which a plurality of solder application holes 2 of the cream solder application screen 1 correspond to apply solder onto the lands 4. [Effect] Since the amount of solder applied on the land can be suppressed, the amount of solder protruding from the land is reduced.
Therefore, the space between the lands can be narrowed, which enables high-density mounting.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cream solder coating screen, and more particularly to a cream solder coating screen suitable for high-density mounting boards.

[0002]

[Prior Art]

 3 is a view showing the IC 20 for surface mounting, FIG. 8 is a view showing the solder applying holes 22 of the cream solder applying screen 23, and FIG. 9 is a view showing a solder applying state on the lands 25 of the substrate 24. For example, in order to solder and fix the IC 20 for surface mounting as shown in FIG. 3, the cream solder applying screen 23 is aligned with the land 25 on the substrate, and the cream solder 26 is applied thereon. The lead terminal 21 of the IC 20 was placed on the substrate 20 and the solder was heated through a reflow furnace to fix the IC 20 on the substrate 24.

As shown in FIG. 8, the solder paste application screen 23 used at this time has a solder application hole 22 of substantially the same size for one land 25, from which cream solder is injected. Then, the cream solder 26 is applied to the land 25 on the substrate 24.

[0004]

[Problems to be solved by the device]

 However, in the conventional cream solder application screen 23, the amount of solder applied from the solder application holes 22 is too large, so that the solder 26 that protrudes from the land 25 becomes smaller when the land-to-land spacing becomes narrower as shown in FIG. Could stick to the solder 26 applied to the adjacent land 25.

In view of the above points, it is an object of the present invention to provide a cream solder coating screen which has a small amount of solder protruding from the land and is suitable for high-density mounting.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has a solder application hole, cream solder is injected from the solder application hole, and cream solder is applied onto a predetermined land provided on the board. In the screen, a plurality of solder application holes correspond to one land, and the solder application holes are closed or narrowed.

[0007]

[Action]

 According to the present invention having the above-mentioned configuration, the amount of solder protruding from the land is reduced, so that the interval between the land can be narrowed and high-density mounting is possible.

[0008]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a solder coating hole 2 of a cream solder coating screen 1 according to an embodiment of the present invention, and FIG. 2 is a diagram showing a solder coating state on a land 4 of a substrate 3.

For example, in order to solder and fix the IC 20 for surface mounting as shown in FIG. 3 to the land 4 on the substrate, the cream solder application screen 1 is aligned and the cream solder 5 is applied. Then, the lead terminal 21 of the IC 20 was placed thereon, and the solder was heated through a reflow furnace to fix the IC 20 on the substrate 1.

As shown in FIG. 1, the cream solder coating screen 1 used at this time has two rectangular solder coating holes 2 a and 2 b for one land 4, from which the cream solder coating holes are formed. And the cream solder 5 is applied to the land 4 on the substrate 3. By doing so, the amount of solder injected from the solder application holes 2a and 2b can be suppressed, so that the amount of solder protruding from the land can be reduced.

In practice, the lead terminal 21 of the IC 20 has a width b = 0.35 mm and a length c = 20.0 mm. As a result of the experiment, when the distance between the lead terminals having the above dimensions is a = 1.0 mm, the conventional cream solder coating screen 23 including the solder coating holes 22 having a width of 0.4 mm and a length of 1.8 mm shown in FIG. The solder applied to the matching land did not stick to each other, but when the lead terminal spacing was a = 0.8 mm, most of the solder applied next was soldered as shown in Fig. 9. It's really tight. Therefore, as shown in FIG. 1, two rectangular solder coating holes 2a and 2b of 0.4 mm in width and 0.8 mm in length according to the present invention are provided at intervals of 0.2 mm to correspond to one land 4 having substantially the same size. When the cream solder coating screen 1 is used, a = 0. Even at 8 mm, it was possible to prevent the applied solder from sticking together.

FIG. 4 shows a cream solder coating screen according to a second embodiment of the present invention. This is a cream solder coating screen in which three solder coating holes 30a, 30b, 30c are associated with one land.

FIG. 5 shows a cream solder coating screen according to a third embodiment of the present invention. This is a cream solder coating screen in which two land-shaped triangular solder coating holes 31a and 31b correspond to one land.

FIG. 6 shows a cream solder coating screen according to a fourth embodiment of the present invention. This is a cream solder coating screen in which two ellipse solder coating holes 32a and 32b are associated with one land.

FIG. 7 shows a cream solder coating screen according to a fifth embodiment of the present invention. This is a cream solder coating screen in which two circular solder coating holes 33a and 33b are provided in one land and the solder coating holes are made to correspond to each other.

[0017]

[Effect of the device]

 As described above, according to the present invention, one land corresponds to a plurality of solder application holes, and the solder application holes are closed or narrowed to reduce the amount of solder, so that the amount of solder protruding from the land is small. Become. Therefore, the space between lands can be narrowed, which enables high-density mounting.

[Brief description of drawings]

FIG. 1 is a view showing solder application holes of a cream solder application screen according to an embodiment of the present invention.

FIG. 2 is a diagram showing a solder application state of a cream solder application screen according to an embodiment of the present invention.

FIG. 3 is a plan view of a surface mounting IC.

FIG. 4 is a diagram showing a cream solder coating screen according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a cream solder coating screen according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a cream solder coating screen according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a cream solder coating screen according to a fifth embodiment of the present invention.

FIG. 8 is a view showing solder application holes of a cream solder application screen which is a conventional example of the present invention.

FIG. 9 is a view showing a solder application state of a cream solder application screen which is a conventional example of the present invention.

[Explanation of symbols]

1, 23 Screen 2a, 2b, 22, 30, 31, 31, 32, 33 Solder application hole 3,24 Substrate 4,25 Land 5a, 5b, 26 Solder 20 Surface mounting IC 21 Lead terminal

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H05K 3/34 H 9154-4E

Claims (1)

[Scope of utility model registration request] 1. A screen for cream solder application which has a solder application hole, injects cream solder through the solder application hole, and applies the cream solder onto a predetermined land provided on the substrate, A cream solder coating screen, wherein a plurality of the solder coating holes correspond to each other, and the solder coating holes are closed or narrowed.