JPH03178189A - Method for mounting surface mount parts - Google Patents

Abstract

PURPOSE:To easily position surface mount parts on a wiring board so as to make the surface mount work easier by putting a guide on the wiring board after it is positioned against pads by using holes and pins and arranging the surface mount parts on the board under the guidance of the guide. CONSTITUTION:A wiring board provided with a plurality of pads 12 at locations corresponding to a plurality of leads 15 which are surface mount parts and with a plurality of holes 16 formed relatively close to the pads 12 is used. A guide 17 which guides at least two side faces of the main bodies of the surface mount parts is put on the board 11 after it is positioned against the pads 12 by inserting a plurality of pins 18 protruding from the guide 17 into the holes 16. Then the leads 15 are set by making them come into contact with the pads 12 respectively being guided by the guide and, after the leads 15 are set, the leads 15 are respectively soldered to the pads 12 by heating the entire body. After soldering, the guide 17 is removed. Therefore, positioning of the surface mount parts to the wiring board becomes easier and the mounting work can be carried out easily.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for mounting surface mount components on a wiring board, which is suitable for application to, for example, a method for mounting pin grid array semiconductor integrated circuit elements.

"Conventional technology" Conventionally, electrical components are mounted on a wiring board by inserting wire leads protruding from the main body of the electrical component into holes formed in the wiring board, and connecting the wires formed at the positions of the holes. This is done by soldering the leads to the wiring on the board. In contrast, a surface mounting method is known in which pads are formed on a wiring board, leads protruding from the main body of an electrical component are placed on the pads, and the pads and leads are soldered. Electrical components in this case, that is, surface-mounted components, generally have leads protruding from the sides of their main bodies. Therefore, it was possible to visually align the leads and the pads on the wiring board relatively easily.

Recently, a semiconductor integrated circuit element called a bin grid array has appeared, which is a packaged semiconductor chip on which a semiconductor integrated circuit is formed. The pin grid array is
A large number of leads, for example 257 leads, are arranged in rows and columns and protrude from the bottom of the main body (package).

This pin grid array is surface mounted by placing the lower end of each lead on one of the pads on the wiring board and soldering the leads and pads.

This surface mounting was carried out by using an automatic machine to bring the bin grid array to a predetermined position on the wiring board.

In this case, positioning can be performed with high precision using an automatic machine, and surface mounting can be performed correctly. However, since an automatic machine is used, it is good for mass production where many bin grid arrays are mounted on one wiring board and this is repeated many times, but for small volume production it is expensive to install an automatic machine. becomes expensive and difficult to realize.

For this reason, in the case of small-volume production, the pin print array is manually brought onto the wiring board and the leads are visually aligned with the pads for surface mounting, but the leads protrude from the bottom of the main body instead of the sides. Because of this, it was very difficult to align the leads and pads because they were shadowed by the main body. Moreover, since the lead pitch (spacing) of the bin grid array is as small as, for example, 127M, fine positioning must be performed, and this positioning is difficult.

According to the present invention, a plurality of bands are formed in a relative positional relationship corresponding to a plurality of leads of a surface mount component, and a plurality of holes are formed in a wiring board relatively close to these pads. A guide that guides at least two sides of the main body of the surface-mounted component is inserted into each of the holes, and a plurality of pins protruding from the bottom of the guide are inserted into the holes, and the guide is positioned on the pad forming surface of the wiring board. The surface mount component is guided so that its leads are brought into contact with each of the pads, and in this state the whole is heated to solder the pads and leads, and then the guide is removed.

"Example" Next, the present invention will be described in detail with reference to the drawings.

As shown in FIG.
2 is formed. Although not shown in the figure, each pad 12 has a solder layer formed on its surface. This example is a case where a bin grid array 13 shown in FIG. 2 is used as a surface mount component mounted on a wiring board 11. The bin grid array 13 has a main body (package) 14 in the shape of a square plate, and a large number, for example, 257
Lead I5 of the book stands out. These leads 15 are arranged in rows and columns at the same pitch (for example, 1.27 mm). Pads 12 are formed in the same relationship as the relative positions of these leads 15. So in this example, pad 1
2 also has 257 pieces arranged in square rows and columns at a pitch of 1.27 squares. A plurality of holes i6, two in this example, are formed in the wiring board 11 relatively close to the arrangement of the pads 12. In this example, the holes 16 are formed close to the centers of two adjacent sides of the square of the pad array.

Next, as shown in FIG. 3, a guide 17 is placed on the pad-shaped bottom surface of the wiring board 11 in close proximity to the array of pads 12.

The guide 17 is a surface mount component, in this example, two adjacent side surfaces 14a and 14b of the main body 14 of the bin grid array 13.
Therefore, in this example, as shown in FIGS. 3 and 4, the guide 17 has two guide pieces 17a.
, 17b are connected at right angles to each other. The inner surfaces of the guide pieces 17a and 17b correspond to the side surface 14a of the main body 14.

14b respectively. This guide piece 17
A pin 18 protrudes from each bottom surface of a and 17b. In this example, the other ends of the guide pieces 17a and 17b are bent inwardly at right angles to form engaging portions 17c and 17d. The distance between the inner surfaces of the guide piece 17a and the engaging portion 17d, that is, the length of the inner surface of the guide piece 17b is slightly larger than the length of the side surface 14b of the main body 14 to be guided. The distance between the inner surfaces of the guide piece 17a, that is, the length of the inner surface of the guide piece 17a is slightly larger than the length of the side surface 14a of the main body 14 to be guided. 2
The guide 17 is placed on the wiring board 11 by inserting the book pins 18 into the two holes 16 of the wiring board 11, respectively. At this time, the distance between the inner surface of the guide 17 and the center of the pad 12 that is close to it is equal to the distance between the side surface 14a of the main body 14 and the pad 15 that is close to it. .

Next, as shown in FIGS. 5 and 6, the main body 14 of the pin grid array 13 is guided by the guide 17, and the pin grid array 13 is placed on the wiring board 11. That is, the side surfaces 14a and 14b of the main body 14 are connected to the guide pieces 17a, respectively.
, 17b, the bin grid array 13 is placed on the wiring board 11 while facing the bin grid array 13. As a result, the lower end of each lead 15 is placed over the center of one pad 12 and comes into contact with the pad 12, respectively.

In this state, the whole is placed in a reflow equipment W (not shown) and heated to melt the solder layer of the pads 12 and solder each pad 12 and each lead 15, respectively.

Next, it is taken out from the reflow apparatus, and after the solder has solidified, the guide 17 is removed as shown in FIG. 7, and surface mounting of the pin grid array 13 onto the wiring board 11 is completed.

The guide 17 may be an extension of the engaging portions 17c and 17d shown in FIG. 4, and may be a square guide or a U-shaped guide. good.

The hole 16 only needs to specify the position and orientation of the guide 17, and the number of holes 16 may be two or more, and the position can be selected arbitrarily.
The pin grid array 13 is positioned on the wiring board 1 by guiding the side surface of the main body 14 with the inner surface of the guide 17.
1, each lead 15 connects to each - pad 1.
The present invention can be applied not only to bin grid arrays but also to surface mounting of other things as zero-surface mounting components that only need to be able to position the bin grid array 13 so that it is placed on top of the bin grid array 13.

"Effects of the Invention" As described above, according to the present invention, the hole 16 and the pin 18
When the guide 17 is positioned with respect to the pad 12 and placed on the wiring board 11, and the surface mount component is placed on the wiring board 11 guided by the guide 17, each lead 15 is placed on each pad 12. The surface mount components can be easily aligned on the wiring board by manual operation, especially when the leads 15 protrude from the bottom surface of the main body 14. It can be easily surface mounted.

If the structure is such that the guide 17 not only guides the main body 14 but also holds the position of the main body 14 as in the above embodiment, after the surface mount components are positioned and arranged on the wiring board by the guide 17. The guide 17 can also be used as a jig to hold the surface-mounted component so that it does not deviate from the position when the surface-mounted component is moved to a heating device for soldering.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a wiring board used in this invention, Fig. 2 is a plan view showing a wiring board used in this invention;
FIG. 3 is a perspective view showing a pin grid array as an example of a surface-mounted component, FIG. 3 is a plan view showing a guide 17 arranged on a wiring board, FIG. 4 is a perspective view showing an example of the guide 17, FIG. 5 is a plan view showing the bin grid array 13 arranged on the wiring board guided by the guide 17, FIG. 6 is a sectional view taken along the line A-A in FIG. 5, and FIG. FIG. 3 is a front view showing a state in which the guide is removed after soldering.

Claims (1)

[Claims] (1) A wiring board in which a plurality of pads are formed on one surface in a relative positional relationship corresponding to a plurality of leads of a surface mount component to be attached to the wiring board, and a plurality of holes are formed relatively close to these pads. On the other hand, a guide for guiding at least two side surfaces of the main body of the surface mount component is placed on the wiring board by inserting a plurality of pins protruding from the bottom surface into the holes respectively, and the surface mount component is attached to the guide. guide the guides and place each lead in contact with each one of the pads, heat the whole in this state and solder each pad and lead, and then remove the guides. Features a mounting method for surface mount components.