JPH07297312A - Leadless chip carrier type electronic part, printed-circuit board and leadless chip carrier type electronic part device - Google Patents

Abstract

PURPOSE:To provide an LCC type electronic part, in which a section not soldered due to the generation of the Manhattan phenomenon at the time of reflowing can be prevented. CONSTITUTION:In a leadless chip carrier type electronic part with a housing section 31, in which an integrated circuit is housed, and a plurality of electrodes 33, etc., mounted on each side of the housing section 31 and soldered and connected to lead sections 43 disposed on a printed board 40, at least one electrode 33 in the electrodes 33, etc., is formed toward the center of the housing section 31, and has an extended section 33a used for joining with the lead sections 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mounts a leadless chip carrier type electronic component (hereinafter referred to as "LCC type electronic component") in which electrodes are arranged on an outer peripheral portion of a housing portion and an LCC type electronic component. The present invention relates to a printed circuit board and an LCC type electronic component device.

[0002]

2. Description of the Related Art Conventionally, a reflow soldering method has been used to mount an LCC type electronic component on a printed circuit board. FIG. 6 is a view showing a conventional LCC type electronic component, (a) is a side view and (b) is a bottom view. FIG. 7 is a diagram showing a printed circuit board on which an LCC type electronic component is mounted. As shown in FIG. 6, the LCC type electronic component 10
Includes a housing portion 11 in which an integrated circuit is housed in a rectangular parallelepiped resin package, and a plurality of electrodes 12 arranged on the outer periphery of the housing portion 11. On the other hand, as shown in FIG. 7, the printed board 20 is a board 21 made of a glass epoxy material.
And the electrode 1 formed by etching on the substrate 21.
2, the lead portion 22 of the copper foil used for bonding with 2, and the substrate 21.
It has a solder resist 23 which is applied on the top of the solder resist and prevents the solder from protruding. In the figure, 21a indicates a portion where the substrate 21 is exposed, and a chain double-dashed line P indicates a range where the LCC type electronic component 10 is placed.

The mounting of such an LCC type electronic component 10 using the printed circuit board 20 by soldering connection has been performed in the following steps. That is, first, the solder paste in which the solder and the flux are mixed is printed on the lead portion 22 of the printed circuit board 20. Next, the LCC type electronic component 10 is placed so that the electrode 12 faces the lead portion 22. Next, the surface of the housing portion 11 opposite to the printed circuit board 20 is pressed with a predetermined pressure by a mounting machine to press the electrode 12 into the solder paste by a predetermined pressing amount and temporarily fix it. Finally, the solder paste was melted by reflow, and the electrode 12 and the lead portion 22 were connected by soldering.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The following problems have been encountered in the process of soldering and connecting the CC type electronic component to the printed circuit board. That is, when the reflow is performed as described above, soldering failure as shown in FIG. 8 may occur. That is, the housing portion 11 is fixed while being tilted during the reflow, and the electrode 12b
And the lead portion 22b are not soldered. Note that FIG. 8 is a cross-sectional view taken along the line Q-Q in FIG. 7 and viewed from the arrow direction. Such a state in which one electrode 12b is soldered in a state of being separated from the lead portion 22b is called a Manhattan phenomenon.

The Manhattan phenomenon occurs for the following reasons. That is, when the melted solder is cooled in the reflow step, a moment as shown by an arrow A in FIG. 9 acts along with the contraction of the solder Sa in the electrode 12a and the lead portion 22a, while the solder Sb With the contraction, a moment as shown by an arrow B in FIG. 9 acts. Therefore, the LCC type electronic component 10 has a moment A acting in a direction that causes the housing 11 to occur with the lower left corner Z of the housing 11 in the drawing as a central axis and a moment B that does not cause the housing 11 to act. Become. At this time, if B> A, the housing portion 11 is normally soldered without tilting, but if A> B, the housing portion 1
1 is caused diagonally, and an unsoldered portion is generated.

On the other hand, soldering failure may occur in another state. That is, in the reflow process,
Due to the thermal expansion of the housing portion 11, warp deformation occurs as shown in FIG. 10, and the electrodes 12c, 1 near the center of the long side of the housing portion 11 are generated.
2d separates from the lead portions 22c and 22d, respectively. Therefore, when cooling, the warp deformation returns to the original value before the solder S
Are condensed, the electrodes 12c, 12d and the lead portions 22c,
22d is not soldered and is unsoldered.

Therefore, the present invention provides an LCC type electronic component capable of preventing unsoldering due to the occurrence of the Manhattan phenomenon during reflow, and a printed circuit board and LCC type electronic component capable of preventing unsoldered due to warpage deformation of the LCC type electronic component during reflow. It is intended to provide a component device.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems and to achieve the object, the present invention provides a housing portion for housing an integrated circuit, and a peripheral portion of the housing portion, which is provided on a printed circuit board. In a leadless chip carrier type electronic component having a plurality of electrodes soldered and connected to a lead part,
At least one of the electrodes has an extending portion formed toward the center of the accommodating portion and used for joining with the lead portion. Further, it is preferable that the electrode having the extending portion is provided at a position other than near the four corners of the accommodating portion.

On the other hand, in a printed circuit board having a lead portion soldered to an electrode provided in an accommodating portion for accommodating an integrated circuit of the leadless chip carrier type electronic component, the leadless chip carrier type electronic component is substantially centered. The central lead portion is provided at a position corresponding to the central electrode provided on the. Further, it is preferable that the central lead portion is connected to the ground.

Further, a leadless chip carrier type having a housing portion for housing an integrated circuit, an electrode provided in the housing portion, and a printed circuit board provided with a lead portion soldered to the electrode. In electronic component equipment,
A central electrode provided in the central portion of the housing portion and a central lead portion at a position corresponding to the central electrode of the printed circuit board are provided.

[0011]

As a result of taking the above-mentioned means, the following effects occur. That is, when the solder in the reflow process is condensed,
A moment that tilts the housing of the LCC-type electronic component is generated at the joint between the electrode of the LCC-type electronic component and the lead of the printed circuit board. On the other hand, a moment in the direction of canceling the above-mentioned moment acts on the extending portion of the joint portion with the lead portion of the printed circuit board. At this time, since the stretched portion is formed sufficiently long, the generated moment becomes large. Therefore, the moment that tilts the housing portion is canceled by this moment, and the Manhattan phenomenon can be prevented from occurring. Therefore, it is possible to prevent the occurrence of soldering failure due to unsoldered solder.

Further, by providing the electrodes having the extending portions other than near the four corners of the accommodating portion, it is possible to arrange the electrodes having the extending portions on the mutually orthogonal sides by avoiding the interference of the extending portions. Therefore, it is possible to prevent the Manhattan phenomenon that occurs in all directions in advance.

On the other hand, a force is generated in the accommodating portion such that the central portion warps upward in the drawing due to heat, but the tension of the solder on the central lead portion provided on the printed circuit board accommodates the LCC type electronic component. The central electrode provided at the center of the portion is attracted, and the housing portion is not warped. Therefore, when the reflow process is completed, the central electrode and the central lead portion are soldered and connected. Along with this, the electrodes provided on each side of the LCC-type electronic component are surely soldered to the lead portions of the printed circuit board, respectively, and it is possible to prevent defective soldering. By connecting the central lead portion to the ground, the layer magnetic shield acts on the LCC type electronic component, and static electricity that interferes with normal operation can be removed.

[0014]

1 (a) and 1 (b) are a side view and a bottom view showing an LCC type electronic component according to a first embodiment of the present invention. In the figure, 30 indicates an LCC type electronic component, 31 is a housing portion in which an integrated circuit is housed in a rectangular parallelepiped resin package, and 32 is a plurality of electrodes arranged on the long side of the housing portion 31. , 33 indicate a plurality of electrodes arranged on the short side of the housing portion 31. An extension portion 33a is formed on the bottom surface side of the accommodation portion 31 of the electrode 33 toward the central portion of the accommodation portion 31, and the tip of the extension portion 33a reaches almost the central portion of the bottom surface of the accommodation portion 31. . As shown in FIG. 2, the printed circuit board 40 is a lead of copper foil used for bonding a substrate 41 made of a glass epoxy material and electrodes 32, 33 of the LCC type electronic component 30 formed by etching on the substrate 41. Parts 42 and 43 (42 is not shown) and lead parts 42 and 43
A solder resist 44 is provided which is applied to a portion where no solder is formed to prevent the solder from protruding. Further, the extending portion 43a of the lead portion 43 arranged at a position corresponding to the electrode 33 is formed to have substantially the same length as the extending portion 33a of the electrode 33.

With this structure, the solder paste printing and the mounting of the LCC type electronic component 30 are performed as in the conventional case. After that, when the reflow process is performed as shown in FIG. 2, the moment A ′ acting to incline the housing portion 31 in the electrode 33 and the lead portion 43 and the housing portion 3 are performed.
A moment B ', which prevents 1 from tilting, is generated. The magnitude of the moment B'has a large value in proportion to the length of the extending portion 33a. Therefore, B '>A', and the storage unit 3
1 is never triggered.

As described above, according to the present embodiment, the occurrence of the Manhattan phenomenon is prevented by making the moment for restraining the inclination larger than the moment for inclining the accommodating portion generated when the molten solder is cooled during the reflow process. However, defective soldering due to unsoldered solder can be prevented.

FIG. 3 is a bottom view showing an LCC type electronic component according to a modification of the first embodiment of the present invention. That is, in the figure, 50 is an LCC type electronic component, 51 is a housing portion, 52 is an electrode,
Reference numeral 53 indicates an electrode having a stretched portion 53a. In addition,
The tip of the extending portion 53a is formed so as to reach almost the center of the accommodating portion 51. The electrodes 53 of the LCC type electronic component 50 are provided so as to avoid the four corners of the housing portion 51.

With this structure, the same effect as that of the above-described embodiment can be obtained. Further, since the electrode 53 having the extending portion 53a is provided so as to avoid the four corners of the housing portion 51, the extending portion as shown by the chain double-dashed line in the figure is also provided on the side orthogonal to the side where the electrode 53 is provided. It is possible to dispose the electrode 54 having it. Therefore, it is possible to prevent the Manhattan phenomenon that occurs in all directions in advance.

The position at which the electrode having the extending portion is provided is not limited to that shown in the above-mentioned embodiment. That is, it may be attached in consideration of the position where the Manhattan phenomenon can be most effectively prevented depending on the type and shape of the LCC type electronic component.

FIG. 4 is a plan view showing a printed circuit board according to a second embodiment of the present invention, and FIG. 5 is a sectional view showing a state in which an LCC type electronic component is mounted. As shown in FIG.
The printed circuit board 60 includes a substrate 61 made of a glass epoxy material,
An L formed by etching on the substrate 61, which will be described later.
Lead parts 62 of a plurality of copper foils used for joining with electrodes 72 provided on each side of CC type electronic component 70, and LCCs provided at positions surrounded by these lead parts 62, which will be described later.
Electrode 7 provided substantially in the center of the electronic component 70
3 is provided with a GND lead portion 63 of a copper foil used for joining with the No. 3 and a solder resist 64 which is applied to a portion where the lead portion 62 and the GND lead portion 63 are not formed and which prevents the solder from protruding. In the figure, 61a indicates a portion where the substrate 61 is exposed, and a chain double-dashed line R indicates a range where the LCC type electronic component 70 is placed.

On the other hand, as shown in FIG. 5, the LCC type electronic component 70 has a housing portion 71 in which an integrated circuit is housed in a rectangular parallelepiped resin package, and electrodes 72 provided on each side of the housing portion 71. And a GND electrode 73 which is provided in the central portion on the bottom surface side of the housing portion 71 and is connected to the ground.

When the LCC type electronic component 70 is mounted on the printed circuit board 60 constructed as described above, it is carried out as follows. That is, the solder paste is printed on the lead portion 62 of the printed circuit board 60. Next, the electrode 72 is connected to the lead portion 6
2, the LCC type electronic component 70 is placed so that the GND electrode 73 faces the GND lead portion 63, and the surface of the housing portion 71 opposite to the printed circuit board 60 is pressed with a predetermined pressure by a mounting machine. As a result, the LCC type electronic component 70 is temporarily fixed on the printed circuit board 60. Next, the solder paste is melted by a reflow process. At this time, a force is generated in the accommodating portion 73 such that the central portion of the accommodating portion warps upward in the figure, but the tension of the solder S between the GND electrode 73 and the GND lead portion 63 causes the GND electrode 73 to move to the GND electrode.
The accommodating portion 73 is attracted to the lead portion 63 and does not warp or deform. Therefore, when the reflow process is completed, as shown in FIG.
As shown in, the entire surface of the GND electrode 73 is covered with the GND lead portion 6
3 is soldered to the entire surface. Along with this, LCC
The electrodes 72 provided on each side of the die electronic component 70 are also reliably soldered to the lead portions 62 on the printed circuit board 60. Since the GND electrode 73 has a function as a layer magnetic shield, static electricity that interferes with normal operation can be removed and product performance can be improved.

As described above, according to this embodiment, the warp deformation of the LCC type electronic component in the reflow process can be prevented by the tension of the solder, so that the non-solder which is likely to occur near the center of the long side of the LCC type electronic component. It is possible to prevent defective soldering. It should be noted that the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

[0024]

According to the present invention, by providing the extending portion on the electrode attached to the accommodating portion, it is possible to cancel the moment to tilt the accommodating portion. For this reason,
It is possible to prevent the occurrence of the Manhattan phenomenon, and it is possible to prevent the occurrence of defective soldering due to unsoldered solder.

On the other hand, by providing the central lead portion on the printed circuit board, the central electrode provided at the center of the accommodating portion of the LCC type electronic component can be attracted by the tension of the solder. Therefore, warp deformation does not occur in the housing portion, and it is possible to prevent defective soldering.

[Brief description of drawings]

FIG. 1 is a diagram showing an LCC type electronic component according to a first embodiment of the present invention, in which (a) is a side view and (b) is a bottom view.

FIG. 2 is a cross-sectional view of the LCC type electronic component of the embodiment mounted on a printed circuit board, taken along line XX in FIG.

FIG. 3 is a bottom view showing a modified example of the same embodiment.

FIG. 4 is a plan view showing a printed circuit board according to a second embodiment of the present invention.

5 is a cross-sectional view of the printed circuit board of the embodiment mounted with an LCC type electronic component taken along the line YY in FIG. 4 and viewed from the direction of the arrow.

FIG. 6 is a view showing a conventional LCC type electronic component,
(A) is a side view, (b) is a bottom view.

FIG. 7 is a plan view showing a conventional printed circuit board.

FIG. 8 shows the Manhattan phenomenon that occurs when mounting an LCC type electronic component on a conventional printed circuit board, as indicated by Q- in FIG.
Sectional drawing cut | disconnected by the Q line and seen from the arrow direction.

FIG. 9 is an explanatory diagram showing a cause of occurrence of the Manhattan phenomenon.

FIG. 10 is a side view showing defective soldering due to warpage deformation of the LCC type electronic component.

[Explanation of symbols]

30, 50, 70 ... LCC type electronic component 31, 51, 71 ... Housing portion 32, 33, 52, 53, 54, 72 ... Electrode 33a, 53a ... Extending portion 40, 60 ... Printed circuit board 41, 61 ... Substrate 43, 62 ... Lead part 43a ... Stretched part 44, 64 ... Solder resist 63 ... GND Lead part 73 ... GND electrode

Claims (5)

[Claims] 1. A leadless chip carrier type electron having an accommodating portion for accommodating an integrated circuit and a plurality of electrodes provided on the peripheral portion of the accommodating portion and soldered to lead portions arranged on a printed circuit board. In the component, at least one of the electrodes has an extending portion formed toward the center of the accommodating portion and used for joining with the lead portion. Leadless chip carrier type electronic component. . 2. The electrode having the extending portion is provided at a position other than near the four corners of the accommodating portion.
Leadless chip carrier type electronic component described in. 3. A printed circuit board having a lead portion soldered and connected to an electrode provided in an accommodating portion for accommodating an integrated circuit of a leadless chip carrier type electronic component, wherein the leadless chip carrier type electronic component is substantially centered. A printed circuit board, wherein a central lead portion is provided at a position corresponding to the central electrode provided on the printed circuit board. 4. The printed circuit board according to claim 3, wherein the central lead portion is connected to a ground. 5. A leadless chip carrier type having a housing portion for housing an integrated circuit, an electrode provided in the housing portion, and a printed circuit board provided with a lead portion soldered to the electrode. In the electronic component device, a leadless chip carrier type electronic device characterized by comprising a central electrode provided in a central portion of the accommodating portion and a central lead portion at a position corresponding to the central electrode of the printed board. Parts device.