JPS6273696A - Placing method for chip type part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] By soldering the electrodes of the chip-shaped component and the comb teeth of the comb-shaped blades of the printed board, damage to the chip-shaped component due to warping of the printed board can be prevented. to prevent

[Industrial application field]

The present invention relates to improvements in the method of mounting chip-shaped components on printed circuit boards.

In recent years, with the advancement of ceramic manufacturing technology, thin square plate-shaped chip-shaped components such as resistors and capacitors have been developed. Chip-shaped components are then soldered onto pads that are densely formed on the surface of the printed circuit board.

At this time, it is required to prevent damage to the chip-shaped part due to the difference in thermal expansion coefficient between the Pudding H fabric and the chip-shaped part.

[Conventional technology]

Fig. 2 is a side sectional view of an electronic device configured by a printed board on which chip-shaped components are mounted, Fig. 3 is a side sectional view of the main part of the conventional mounting method, and Fig. 4 is a perspective view of the main part of the conventional example. be.

In FIGS. 3 and 4, electrodes 2 are formed on a pair of opposing side surfaces of the chip-shaped component 1 and on a part of the bottom surface including a square line in contact with the side surfaces. The electrode 2 portion on the bottom has a rectangular shape and is formed parallel to and facing the square wire of the chip-shaped component 1.

The printed circuit board 3 on which the chip-shaped component 1 is mounted has a ground conductor foil 4 almost entirely on the back surface, and a conductor pattern 1 on the front surface.
1 and a pad 10 on which a chip-shaped component 1 is mounted is provided at the end of the conductor pattern 11 facing each other.

This pad 10 is formed to face the pair of electrodes 2 of the chip-shaped component 1, and has a rectangular shape that is larger than the shape of the bottom surface portion of the electrode 2.

After applying, for example, creamy solder to such a pad 10 by printing, etc., the electrode 2 is aligned with the pad 10, and the chip-shaped component 1 is placed as shown by the chain line frame in FIG.

Next, the printed board 3 is heated to harden the creamy solder and become solder 13, and the chip-shaped parts are adhered and mounted.

The printed board 3 on which the chip-shaped component 1 is mounted in this way is
For example, it is incorporated into an electronic device as shown in FIG.

The printed board 3 is inserted into the box-shaped metal casing 5 with the grounding conductor foil 4 side facing downward, parallel to the bottom plate of the casing, and the grounding conductor foil 4 portions on the opposing side edges are attached to the side walls of the metal casing 5. It is fixed by soldering.

[Problem that the invention seeks to solve]

However, the chip-shaped parts mounted on the printed board by the above-mentioned conventional means have a thermal expansion coefficient that is approximately one order of magnitude larger than that of the metal casing and the ground conductor foil.
When the ambient temperature changes, the component mounting surface of the printed circuit board becomes convex (
It warps in the direction indicated by the dotted line in Figure 2).

Since the printed board is warped in this way, a large tensile force is applied to the chip-shaped parts, causing a problem that the chip-shaped parts are damaged.

[Means for solving problems]

In order to solve the above-mentioned conventional problems, the present invention, as shown in FIG. On the opposite side, a comb-shaped pad 20 is provided on the surface of the printed board 3, and the electrode 2 is placed on the comb teeth 21 of the pad 20 and soldered.

[Effect]

According to the means of the present invention, the chip-shaped component 1 and the printed board 3 are fixed by soldering only at the comb teeth 21 portion of the pad 20.

Therefore, when the printed board 3 is warped and a tensile force is applied to the chip-shaped component 1 as a result, the tensile force is smaller than that in the conventional method, and the tensile force is stronger in the band-shaped portion corresponding to the comb teeth 21. , the band-like part without comb teeth (corresponding to the tooth spacing) acts on a weak, strong and weak vertical striped pattern.

Therefore, in the chip-shaped part as a whole, the parts with weak tensile force reinforce the parts with strong tensile force, and there is little risk of breakage.

〔Example〕

The present invention will be specifically explained below with reference to illustrated examples. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a perspective view of a main part of an embodiment of the present invention, in which a thin square plate-shaped chip-shaped component 1 has a pair of opposing side surfaces;
And an electrode 2 is formed on a part of the bottom surface including the square wire in contact with this side surface.

A pair of conductor patterns 11 formed on the surface of the printed board 3
A comb-shaped pad 20 is provided at the end of each electrode, corresponding to each electrode 2. The connecting portion 20a of the pad 20, which is orthogonal to the conductor pattern 11, has a narrow rectangular shape whose length is longer than the width of the chip-shaped component 1 as desired.
A desired number of comb teeth 21 are formed in parallel.

The tooth height of the comb teeth 21 is formed on the bottom surface of the electrode 2 to be larger than the width of the portion.

After applying, for example, creamy solder to the comb teeth 21 portion of the pad 20, the electrode 2 is attached to the pad 2.
0, place the chip-shaped component 1 as shown by the dashed line frame in FIG. There is.

As described above, although the chip-shaped component 1 and the printed board 3 are soldered together only through the comb teeth 21 of the pad 20, there is no problem as they have a sufficient electrical connection area.

On the other hand, mechanically, since the total fixed area is small, when the printed board 3 warps due to temperature change and as a result, a tensile force is applied to the chip-shaped component 1, the tensile force is Smaller than adhesive means.

Further, since the fixed portion is the tip of the comb teeth 21, the fixed portion and the non-fixed portion are arranged in parallel alternately. Therefore, the tensile force applied to the chip-shaped part 1 acts on a vertical striped pattern of strong and weak strength, with the band-shaped portion corresponding to the comb teeth 21 being strong and the band-shaped portion without comb teeth (corresponding to the tooth spacing) being weak. .

Therefore, for the chip-shaped part as a whole, the parts with weak tensile force reinforce the parts that are strongly pulled.
There is little risk of damage.

〔Effect of the invention〕

As explained above, the present invention has a comb-teeth shape in the part to which the chip-shaped components are soldered, so that even if the printed board warps, there is less risk of the chip-shaped components being damaged.
It has excellent practical effects.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the main part of an embodiment of the present invention, Fig. 2 is a side cross-sectional view of an electronic device constituted by a printed board on which chip-shaped parts are mounted, and Fig. 3 is a side view of the main part according to the conventional mounting method. The sectional view and FIG. 4 are perspective views of essential parts of a conventional example. In the figure, 1 is a chip-shaped component, 2 is an electrode, 3 is a printed board, 4 is a grounding conductor foil, 5 is a metal casing, 10.20 is a pad, 11 is a conductive pattern, 20a is a connecting part, 1st Nichiden +1 〈辷ζ6２I)　　　〈〈〈〈〷ζ6〉〉〈〈〈〉〷ζ6〉I) figure

Claims (1)

[Claims] A chip-shaped component (1) having a rectangular electrode (2) on the bottom surface.
) on the printed board (3) by soldering, a comb-shaped pad (20) is provided on the surface of the printed board (3) opposite to the electrode (2), and the comb of the pad (20) A method for mounting a chip-shaped component, comprising placing the electrode (2) on the tooth (21) and soldering it.