JPH0583071A - Surface mount electronic components - Google Patents

Abstract

(57) [Abstract] [Purpose] An object is to provide a thin and highly reliable surface mount electronic component capable of relaxing and absorbing thermal or mechanical strain. [Structure] Buffer pieces 31, 32, 33, and 34 are attached to extraction electrodes provided on the bottom surface of the chip-type electronic component 1.
The buffer pieces are internal electrode connection parts 31a, 32a, 33a, 34.
a and the external electrode connecting portions 31c, 32c, 33c, 34c and the connecting portions 31b having flexibility by connecting these connecting portions.
32b, 33b, 34b. An electrode is formed on the surface of the buffer piece, and this electrode is laid on the back surface to connect to the outside. Further, a buffer plate in which these buffer pieces are connected to each other and integrated may be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin surface mount type electronic component, and more particularly to an electronic component in consideration of mounting on a printed wiring board.

[0002]

2. Description of the Related Art With the miniaturization of electronic devices, it is required that electronic components have a low overall height and be mounted on a printed wiring board at a high density, and that the mounting is performed by an automatic machine. There is. In order to meet this demand, there has been an urgent movement to make electronic parts thin and leadless chip type. The chip-type electronic component 7 as shown in FIG. 9 can be made smaller in volume including the total height, as compared with electronic components such as a crystal resonator in which a hermetically sealed metal can is used. In addition, 71, 72
Is solder, and 8 is a printed wiring board. A chipped electronic component as shown in FIG. 9 has a lead electrode provided on the lower surface thereof, and the lead electrode connects to an external electrode such as a printed wiring board. This connection is a flow of automation of assembly of electronic devices, and electromechanical joining of chip type electronic components to a printed wiring board is often performed by reflow soldering. Reflow soldering is a method in which an appropriate amount of solder is supplied in advance to a joint and the solder is melted by a heat source from the outside to perform soldering.

[0003]

The chip-type electronic component is
A package made of ceramic or the like is used, and it is generally possible to make it thin and have a low profile, and as described above, it is firmly electromechanically joined to the printed wiring board by soldering or the like. However, since it is leadless, it does not have a portion where the shrinkage strain at the time of hardening the solder or the strain due to the deformation of the substrate is alleviated. For example, depending on the electronic device, the chip-type electronic component may be mounted on a printed wiring board and then the deformation of the board may be corrected. In most cases, electronic parts are subjected to a heat cycle test or an aging test in order to secure or confirm the reliability.
What is a heat cycle test? The ambient environmental temperature of electronic parts is, for example, -40 ° C → 25 ° C for 3 minutes → 100 ° C for 30 minutes → 25
The cycle of 3 minutes at -40 ° C and 30 minutes at -40 ° C is repeated several hundred times. However, by repeating such a cycle, the bonding material such as solder expands and contracts. In the case of a chip-type electronic component, in such cases, it does not have a portion for relaxing strain, and therefore, the package on the chip-type electronic component side is cracked and the airtightness of the package is lowered, or In some cases, the joint surface with each component was peeled off and the conductive state became unstable.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a thin and highly reliable surface mount electronic component capable of absorbing and absorbing thermal or mechanical strain. is there.

[0005]

A surface mount type electronic component according to the present invention is a surface mount type electronic component in which a plurality of extraction electrodes provided on the bottom surface of a chip type electronic component are respectively provided with a buffer piece. Is an internal connection part connected to the chip type electronic component side, an external connection part for making an external connection, and a flexible connecting part that connects these connection parts. It is characterized in that electrodes are formed up to the portion. Usually, the connecting portion has a width narrower than that of each connecting portion or is bent to have a flexible structure. Further, in the above configuration, the buffer pieces may be mechanically connected to each other and attached as a buffer plate to the bottom surface of the chip-type electronic component.

[0006]

The buffer piece provided on the bottom surface of the chip-type electronic component alleviates various strains generated between the chip component and the printed wiring board on which the component is mounted. This buffer piece
Since the internal connecting portion connected to the chip type electronic component side, the external connecting portion for making the external connection, and the flexible connecting portion connecting these both connecting portions, the internal connecting portion and the external connecting portion are connected. The parts are connected in a flexible manner and create a cushioning effect. Of course, since the cushioning piece is manufactured from a single plate material, the total height of the chip-type electronic component does not become unnecessarily high. Further, by connecting these buffer pieces to form an integrated buffer plate, the handling is simple and the workability in manufacturing is improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings, taking a surface mount type crystal oscillator as an example. First Embodiment FIG. 1 is a perspective view showing a first embodiment according to the present invention,
2 is a plan view showing the front surfaces (chip-type crystal oscillator side) of four buffer pieces attached to the chip-type crystal oscillator (chip-type electronic component), and FIG. 3 is a plan view showing the back surfaces of the four buffer plates. is there. The chip-type crystal oscillator 1 accommodates a crystal vibrating piece having electrodes formed therein, and the electrodes extracted from the crystal vibrating pieces are extraction electrodes 11, 12, 13, and 14.
(Partly not shown). The extraction electrodes 11, 12, 13, and 14 are chip-type crystal oscillators 1
Is pulled out to the bottom of. Cushioning pieces 31, 32, 33,
Reference numeral 34 is made of a resin material such as epoxy or polyimide, and has internal connection portions 31a, 32a, 33a, 34a for connection with chip type electronic components, and external connection portions 31c, 32c for connection with a printed circuit board or the like. 33c, 34c
And connecting portions 31b, 32b, 3 for connecting these both connecting portions
3b and 34b. The width of the connecting portion is narrower than that of both connecting portions, so that both connecting portions can be moved flexibly. An internal connection electrode 41 is provided on the chip crystal oscillator side (front surface) of each of the buffer pieces 31, 32, 33, 34.
a, 42a, 43a, 44a and external connection electrodes 41c,
42c, 43c, 44c and connection electrodes 41b, 42b, 43b, 44b connecting both connection electrodes are formed by means such as vapor deposition. Further, external connection electrodes 41c, 42c, 43c, 44c are arranged around the external connection portion on the back surface of each buffer piece. 2 and 3, reference numeral 1a denotes the outer shape of the bottom surface of the chip type crystal oscillator. The buffer pieces 31, 32, 33, 34 thus configured are arranged on the bottom surface of the chip-type crystal oscillator 1, and the extraction electrodes 11, 12, 13, 14 of the chip-type crystal oscillator and the internal connection of the respective buffer pieces are arranged. The electrodes 41a, 42a, 43a, 44a are electrically and mechanically connected by a conductive bonding material. External connection to the printed wiring board etc. is made with external connection electrodes.

Second Embodiment FIG. 4 is a perspective view showing a second embodiment according to the present invention.
FIG. 5 is a front view of FIG. 6 is a plan view showing the chip-type electronic component side (front surface) of the buffer plate, and FIG. 7 is a plan view showing the back surface of the buffer plate. Similarly to the first embodiment, the chip-type crystal oscillator 1 accommodates therein a crystal vibrating reed having electrodes formed therein, and the electrodes extracted therefrom are extraction electrodes 11, 12, 13, 14 (partial view). (Not shown) electrically connected. This extraction electrode 11, 12,
Reference numerals 13 and 14 are drawn out to the bottom surface of the chip type crystal oscillator 1. The buffer plate 5 is made of a resin material such as epoxy or polyimide. As shown in FIGS. 6 and 7, the internal connection portion 51a,
52a, 53a, 54a and external connection parts 51c, 52
c, 53c, 54c, connecting portions 51b, 52b, 53b, 54b connecting these both connecting portions, and notch portions 51d, 52d, 53d, 54d in each external connecting portion, and one sheet as a whole. It forms a buffer plate. Each connecting portion and the external connecting portion are provided by cutting the buffer plate 5, and are slightly bent downward to increase the buffering action. Similar to the first embodiment, internal connection electrodes 61a, 62a, 63a, 64a, connection electrodes 61b, 62b, 63b, 64b, and external connection electrodes 61c, 62c, 63c, 64c are provided on each part of the surface of the buffer plate. External connection electrodes 61c, 62c, 63c, 64c are formed around the external connection portion on the back surface of the buffer plate through the cutouts. The buffer plate 5 configured in this manner is arranged on the bottom surface of the chip-type crystal oscillator 1, and the extraction electrodes 11, 12, 13, 14 of the chip-type crystal oscillator and the internal connection electrodes 61a, 62a, 63a of the buffer plate, 64a is electrically and mechanically connected with a conductive bonding material.

The present invention is not limited to the above embodiment, and the material of the buffer piece or the buffer plate may be a flexible plate having a metal plate as a core and an insulating material coated on the surface thereof. Further, the external connection portion of the buffer plate does not necessarily have to be bent downward as in the above embodiment, but for example, as shown in FIG. 8, the connecting portions 55b, 56b, 57b, 5 are connected.
It is advisable to bend 8b several times in a plane so that a buffer function is easily generated. In FIG. 8, 55a, 56a,
57a and 58a are internal connection parts, 55c, 56c and 57.
Reference numerals c and 58c are external connection parts.

[0010]

The buffer piece or the buffer plate provided on the bottom surface of the chip-type electronic component such as the crystal oscillator connects the internal connection portion for electrically connecting to the chip-type electronic component side with the printed wiring board or the like. Since the external connecting portion to be performed and the connecting portion having flexibility and connecting both connecting portions are provided, both connecting portions are in a flexible state, whereby the chip-type electronic component and this component are mounted. A buffer function is obtained between the printed wiring board and the printed wiring board. Therefore, thermal and mechanical strains that occur between the chip-type electronic component and the printed wiring board, for example, can be mitigated, and the connection between the chip-type electronic component and the printed wiring board becomes unstable, or the chip-type electronic component is unstable. Due to the large strain on the side, the parts are no longer cracked or otherwise damaged. Since the cushioning piece or the cushioning plate is made of one plate, the overall thickness does not increase significantly, and it is possible to secure the low profile required for the electronic components mounted on the printed wiring board. Also,
With the structure as set forth in claim 2, since one plate can be used as the buffer plate, workability during manufacturing is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a surface mount electronic component according to the present invention.

FIG. 2 is a plan view of the surface of the buffer plate shown in the first embodiment.

FIG. 3 is a plan view of the back surface of the buffer plate shown in the first embodiment.

FIG. 4 is a perspective view showing a second embodiment of the surface mount electronic component according to the present invention.

5 is a front view of FIG.

FIG. 6 is a plan view of the surface of the buffer plate shown in the second embodiment.

FIG. 7 is a plan view of the back surface of the buffer plate shown in the second embodiment.

FIG. 8 is a plan view of the surface of a buffer plate showing another embodiment.

FIG. 9 is a perspective view showing a conventional example.

[Explanation of symbols]

1 Chip type crystal oscillator (chip type electronic component) 31, 32, 33, 34 Buffer piece 31a, 32a, 33a, 34a, 51a, 52a, 5
3a, 54a, 55a, 56a, 57a, 58a Internal connection parts 31b, 32b, 33b, 34b, 51b, 52b, 5
3b, 54b, 55b, 56b, 57b, 58b Connection parts 31c, 32c, 33c, 34c, 51c, 52c, 5
3c, 54c, 55c, 56c, 57c, 58c External connection parts 41a, 42a, 43a, 44a, 61a, 62a, 6
3a, 64a Internal connection electrodes 41b, 42b, 43b, 44b, 61b, 62b, 6
3b, 64b Connection electrodes 41c, 42c, 43c, 44c, 61c, 62c, 6
3c, 64c External connection electrode

Claims (2)

[Claims] 1. A surface-mounted electronic component in which a buffer piece is provided on each of a plurality of extraction electrodes provided on the bottom surface of the chip electronic component, wherein the buffer piece is an internal connection portion connected to the chip electronic component side. A surface characterized in that an electrode is formed from the internal connection part to the external connection part, which is composed of an external connection part for making an external connection and a flexible connecting part connecting these both connection parts. Mounted electronic components. 2. The buffer pieces are mechanically connected to each other,
The surface type electronic component according to claim 1, wherein the surface type electronic component is attached to the bottom surface of the chip type electronic component as a buffer plate.