JPH08148798A - Mounting structure of surface mounted part - Google Patents

Abstract

PURPOSE: To inhibit effectively the Manhattan phenomenon of a chip part by forming a pad for soldering an electrode of a surface mounting part in a shape protruding toward the outside of a surface mounting product. CONSTITUTION: Pads 2a and 2b of a printed board 1 are formed in a shape protruding toward the outside of a chip part 4 and electrodes 5a and 5b of the chip part are respectively mounted to the pads 2a and 2b through a cream solder. Since this enables a moment due to a melting solder of the lower part of the chip to be made large and a moment due to a melting solder outside the chip end to be made small, the Manhattan phenomenon can be effectively inhibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for mounting a surface mount component (hereinafter referred to as a chip component) on a printed board.

[0002]

2. Description of the Related Art One of the methods for mounting chip parts on a printed circuit board is a method by reflow soldering.
In the mounting method by this reflow soldering, as shown in FIG.
As shown in FIG. 9, cream solder 3 is applied to the pads 2a and 2b having a rectangular shape in a plane formed on the printed circuit board 1, and the electrodes 5 of the chip component 4 are applied to these pads 2a and 2b.
The chip component 4 is mounted in correspondence with a and 5b, and then
By heating the cream solder 3, the chip component 4 is soldered onto the printed board 1 as shown in FIG.

[0003]

However, in the above-mentioned mounting method by reflow soldering, in particular,
When the chip parts are very small, the chip parts start up,
The so-called Manhattan phenomenon is likely to occur. Therefore, conventionally, after mounting the chip components, the mounting state of each chip component is confirmed, and the chip component in which the Manhattan phenomenon occurs is corrected by using a soldering iron. Therefore, there is a problem that a great number of man-hours are required and cost is increased.

Further, conventionally, since the pads 2a and 2b are formed on the printed circuit board 1 and the chip component 4 is mounted thereon, the dimension of the printed circuit board 1 after mounting in the thickness direction is large. And this is why the printed circuit board 1
There is also a problem in that the package for mounting is large.

A first object of the present invention is to solve the above-mentioned conventional problems and to provide a mounting structure of a chip component appropriately configured so as to effectively suppress the Manhattan phenomenon of the chip component. .

In addition to the first object, the second object is to reduce the dimension in the thickness direction after the chip parts are mounted,
Therefore, it is an object of the present invention to provide a mounting structure of a chip component that is appropriately configured so that the package can be thinned.

[0007]

In order to achieve the above first object, the present invention has a structure for mounting a chip component on a printed circuit board, which is provided on the printed circuit board and solders electrodes of the chip component. The pad for attachment is formed in a convex shape toward the outside of the chip component.

Further, the present invention has a structure for mounting a chip component on a printed circuit board, wherein both ends of the chip component having electrodes are formed so as to taper outwardly. It is a feature.

Further, the present invention has a structure for mounting a chip component on a printed circuit board, and is characterized in that electrodes on both side surfaces of the chip component are narrowly formed.

Further, the present invention has a structure for mounting a chip component on a printed circuit board, wherein the electrode of the chip component is positioned on a pad provided on the printed circuit board for soldering an electrode of the chip component. It is characterized in that a step difference is formed.

Furthermore, the present invention has a structure for mounting a chip component on a printed circuit board, wherein the chip component is
A protruding member is provided on a bottom portion of the printed circuit board, and an engaging portion that engages with the protruding member is provided on the printed circuit board between pads for soldering opposite electrodes of the chip component. It is what

Further, the present invention has a structure for mounting a chip component on a printed circuit board, wherein the chip component is
A fixing terminal is provided on the bottom of the printed circuit board,
It is characterized in that a dummy pad for soldering the fixing terminal is provided between the pads for soldering the facing electrodes of the chip component, respectively.

In order to achieve the second object, the present invention has a structure in which a chip component is mounted on a printed circuit board, wherein electrodes provided on the printed circuit board and facing each other of the chip component are soldered to each other. It is characterized in that a recess into which the chip component is inserted is provided between the pads for carrying out.

[0014]

As shown in FIG. 1, the pad 2 of the printed circuit board 1
The cream solder 3 is applied on a and 2b, and the electrodes 5a and 5b of the chip component 4 are made to correspond thereto and the chip component 4
When mounted, the cream solder 3 is attached to the chip component 4.
Surface tensions f1 and f2, own weight f3, and buoyancy force f4. After that, when the chip component 4 tries to rise when the cream solder 3 is heated, as shown in FIG. 2, the chip component 4 has a moment T1 due to its own weight, a moment T2 due to molten solder at the bottom of the chip, and A moment T3 due to the molten solder, a moment T4 due to the buoyant force of the inert liquid, a moment T5 due to the adhesive force of the solder paste, a moment T6 due to vibration, and a moment T7 of the buoyant force due to the generated gas staying on the bottom surface of the chip act.

Here, the moments T3, T4, T6, and T7 act in a direction in which the chip component 4 is raised, that is, in a direction that promotes the Manhattan phenomenon, and the moment T
1, T2 and T5 act in a direction to return the chip component 4 to the original state, that is, in a direction to suppress the Manhattan phenomenon. Therefore, in order to prevent the Manhattan phenomenon, the moments T1, T2 and T5 should be increased and the moments T3, T4, T6 and T7 should be decreased.

According to the present invention, as described above, the pad for soldering the electrode of the chip component is formed in a convex shape toward the outside of the chip component, so that the moment T2 is obtained.
Can be made large and the moment T3 can be made small, and by forming both ends of the chip component each having an electrode so as to taper outward,
The moment T3 can be reduced, and similarly, by forming the electrodes on both side surfaces of the chip component with a narrow width, the moment T3 can be reduced, and by forming a step for positioning the electrode of the chip component on the pad, When the chip part is about to rise, the fulcrum of the moment T3 can be shifted to be small, and the Manhattan phenomenon can be effectively suppressed.

Further, by providing a protruding member on the bottom of the chip component and providing an engaging portion for engaging the protruding member between the pads of the printed circuit board, it is possible to prevent the chip component from rising due to the engagement. Further, by providing the fixing terminal on the chip component and by providing the dummy pad for soldering the fixing terminal between the pads of the printed circuit board, the moment T5 can be increased and the Manhattan phenomenon can be effectively suppressed. It will be possible.

Further, by providing the recesses between the pads of the printed circuit board, into which the chip components are inserted, the chip components can be embedded in the printed circuit board, thereby effectively suppressing the Manhattan phenomenon. The dimension in the thickness direction after mounting the chip component can be reduced, and the package can be thinned.

[0019]

3 and 4 show a first embodiment of the present invention. In this embodiment, the pads 2a and 2b of the printed circuit board 1 are formed in a convex shape toward the outside of the chip component 4, and the electrodes 5a and 5b of the chip component 4 are connected to the pads 2a and 2b via the cream solder 3. Each is to be implemented.

Thus, the electrodes 5a, 5 of the chip component 4 are
If the pads 2a, 2b for soldering b are formed in a convex shape toward the outside of the chip component 4, in FIG. 2, the moment T2 due to the molten solder under the chip is large and the moment due to the molten solder outside the chip end is large. Since T3 can be reduced, the Manhattan phenomenon can be effectively suppressed.

FIG. 5 shows a second embodiment of the present invention. In this embodiment, each of the electrodes 5 of the chip component 4 is
Both ends having a and 5b are formed so as to taper outwardly.

With this structure, the chip component 4 is
When soldered to the rectangular pads 2a and 2b as shown in FIG. 19, the electrodes 5a and 5 are connected as shown by phantom lines in FIG.
Since the cream solder 3 is reduced by thinning the both ends having b, in FIG. 2, the moment T3 for starting the chip component 4 by the molten solder on the outside of the chip end can be reduced, and the Manhattan phenomenon is effectively suppressed. can do.

FIG. 7 shows a third embodiment of the present invention. In this embodiment, the electrodes 5a, 5b on both side surfaces of the chip component 4 are formed narrowly. Therefore, if the chip component 4 is soldered to the rectangular pads 2a and 2b as shown in FIG.
As in the second embodiment, since the moment T3 due to the molten solder on the outside of the tip end shown in FIG. 2 can be reduced,
The Manhattan phenomenon can be effectively suppressed.

8 and 9 show a fourth embodiment of the present invention. In this embodiment, steps are formed on the pads 2a and 2b of the printed circuit board 1 to position the electrodes 5a and 5b of the chip component 4, and the chip component 4 is soldered to the pads 2a and 2b via the cream solder 3. It is something that is done.

In this case, as shown in FIG. 10, when the force of F3 is applied when the chip component 4 is mounted on the pads 2a, 2b, the chip component 4 initially rotates with the bottom side as the fulcrum O. Therefore, if the thickness of the chip component 4 is L1,
The moment T3 that tries to raise the chip component 4 is
It is represented by the product of L1 and F3.
As shown in FIG. 11, the electrode on the side surface (the electrode 5b in FIG. 11) abuts on the top of the step of the pad 2b, the fulcrum O is displaced by the step, and the arm is shortened to L2, so that the moment T3 is reduced. Therefore, the Manhattan phenomenon can be effectively suppressed.

12 and 13 show a fifth embodiment of the present invention. In this embodiment, a protrusion 6 is provided on the bottom of the chip component 4, and a hole 7 into which the protrusion 6 is inserted is formed between the pads 2a and 2b of the printed circuit board 1 to form the protrusion 6
Is inserted into the hole 7 and the electrodes 5a and 5b are soldered to the pads 2a and 2b via the cream solder 3 so that the chip component 4 is mounted on the printed circuit board 1.

With this structure, when the cream solder 3 is heated to solder the chip component 4, when the chip component 4 tries to rise, the protrusion 6 is prevented from hitting the inner circumference of the hole 7 and rising. Therefore, the Manhattan phenomenon can be effectively suppressed.

14 and 15 show a sixth embodiment of the present invention. In this embodiment, in order to provide the fixing terminal 8 extending in the width direction at approximately the center of the bottom of the chip component 4 and soldering the fixing terminal 8 between the pads 2a and 2b of the printed board 1. The dummy pads 9 are provided to connect the electrodes 5a and 5b of the chip component 4 to the cream solder 3
The pads 2a and 2b are soldered to the dummy pads 9 via the cream solder 3, and the fixing terminals 8 are also soldered to the dummy pads 9 via the cream solder 3.

With this configuration, the moment T5 due to the adhesive force of the solder paste in FIG. 2 can be increased, so that the Manhattan phenomenon can be effectively suppressed.

FIG. 16 shows a seventh embodiment of the present invention. This embodiment differs from the sixth embodiment in that the fixing terminal 8 on the bottom of the chip component 4 is circular. Therefore, also in this embodiment, as in the sixth embodiment, the moment T5 due to the adhesive force of the solder paste can be increased, so that the Manhattan phenomenon can be effectively suppressed.

17 and 18 show the eighth embodiment of the present invention. In this embodiment, the printed circuit board 1
A recess 10 into which the chip component 4 is inserted is provided between the pads 2a and 2b, and the chip component 4 is inserted into the recess 10 and the electrodes 5a and 5b are soldered to the pads 2a and 2b via the cream solder 3. It is designed to be implemented.

By embedding the chip component 4 in the printed board 1 in this manner, the Manhattan phenomenon can be effectively suppressed, and the dimension in the thickness direction after the chip component is mounted can be reduced. It can be made thinner.

[0033]

As described above, according to the present invention, it is possible to effectively suppress the so-called Manhattan phenomenon in which the chip component rises, and to embed the chip component in the recess formed in the printed board. Is also
Since the dimension in the thickness direction after mounting the chip component can be reduced, the package can be thinned.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a force acting on a chip component when mounted on a printed circuit board.

FIG. 2 is a diagram for explaining a moment acting on a chip component when the chip component is soldered.

FIG. 3 is a perspective view showing a state before mounting the chip component of the first embodiment of the present invention.

FIG. 4 is likewise a perspective view showing a state after mounting.

FIG. 5 is a perspective view showing a chip part according to a second embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the second embodiment.

FIG. 7 is a perspective view showing a chip part according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing a state before mounting a chip part according to a fourth embodiment of the present invention.

FIG. 9 is likewise a perspective view showing a state after mounting.

FIG. 10 is a diagram for explaining the operation of the fourth embodiment.

FIG. 11 is also a diagram for explaining the operation of the fourth embodiment.

FIG. 12 is a perspective view showing a state before mounting a chip part according to a fifth embodiment of the present invention.

FIG. 13 is likewise a sectional view showing a state after mounting.

FIG. 14 is a perspective view showing a state before mounting the chip part of the sixth embodiment of the present invention.

FIG. 15 is likewise a sectional view showing a state after mounting.

FIG. 16 is a perspective view showing a state before mounting a chip part according to a seventh embodiment of the present invention.

FIG. 17 is a perspective view showing a state before mounting a chip part according to an eighth embodiment of the present invention.

FIG. 18 is likewise a sectional view showing a state after mounting.

FIG. 19 is a perspective view showing a state before mounting a chip component according to a conventional mounting structure.

FIG. 20 is also a perspective view showing a state after mounting.

[Explanation of symbols]

 1 Printed Circuit Board 2 Pads 2a, 2b 3 Cream Solder 4 Chip Components 5a, 5b Electrode 6 Projection 7 Hole 8 Fixing Terminal 9 Dummy Pad 10 Recess

Claims (7)

[Claims] 1. A structure for mounting a surface mount component on a printed circuit board, wherein a pad provided on the printed circuit board for soldering an electrode of the surface mount component is directed toward the outside of the surface mount component. A mounting structure for a surface mount component, which is formed in a convex shape. 2. A structure for mounting a surface mount component on a printed circuit board, wherein both ends of the surface mount component each having an electrode are formed so as to taper outwardly. Mounting structure for surface mount components. 3. A mounting structure for a surface mount component, comprising a structure for mounting a surface mount component on a printed circuit board, wherein electrodes on both side surfaces of both ends of the surface mount component are narrowly formed. 4. A structure for mounting a surface mount component on a printed circuit board, wherein an electrode of the surface mount component is located on a pad provided on the printed circuit board for soldering an electrode of the surface mount component. A mounting structure for a surface mount component, characterized in that a step is formed. 5. A structure for mounting a surface mount component on a printed circuit board, wherein the surface mount component is provided with a projecting member at a bottom thereof, and the printed circuit board is provided with electrodes facing the surface mount component. A mounting structure for a surface mount component, characterized in that an engaging portion that engages with the protruding member is provided between pads for soldering. 6. A structure for mounting a surface mount component on a printed circuit board, wherein the surface mount component is provided with a fixing terminal at a bottom thereof, and the printed circuit board is provided with electrodes facing the surface mount component. A mounting structure of a surface mount component, wherein dummy pads for soldering the fixing terminals are provided between pads for soldering. 7. A structure for mounting a surface mount component on a printed circuit board, wherein the surface mount component is provided between pads provided on the printed circuit board for soldering opposite electrodes of the surface mount component respectively. A mounting structure for a surface mount component, which is provided with a recessed portion for entering.