JP2001007675A - Surface-mounted type electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-mounted type electronic component with high reliability, where a short-circuit between terminal electrode films due to exfoliation of an unwanted formed film can be surely prevented. SOLUTION: This surface-mounted type electronic component has terminal electrode films 12-14 formed by applying film forming processing, such as plating to a surface of an electronic component main body 11. The terminal electrode films 12, 14 are respectively formed to both ends of the electronic component main body 11. The lead end of an internal electrode exposed to the surface of the electronic component main body 11 is covered by the terminal electrode films 12, and in the case of forming the terminal electrode films 12-14, forming of an unwanted film on the lead end of the internal electrode can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount electronic component, and more particularly, to a surface mount electronic component having a terminal electrode film formed by a film forming process such as plating.

[0002]

2. Description of the Related Art FIG. 11 shows an example of this type of conventional surface mount type electronic component. The surface-mounted electronic component 60 has three terminal electrode films 12 to 14 formed on the surface of an electronic component body 11 having a rectangular parallelepiped shape. These terminal electrode films 12
Among these, the terminal electrode films 12 and 14 are formed on both ends of the electronic component body 11 and function as input terminals and output terminals, respectively. The terminal electrode film 13 is formed between the terminal electrode films 12 and 14 and functions as a ground terminal.

[0003] The electronic component body 11 is formed by bonding ceramic cover members 16 and 17 to the upper and lower sides thereof with a piezoelectric substrate 15 interposed therebetween. Vibrating electrodes 21 and 22 are formed as internal electrodes on the main surfaces of the piezoelectric substrate 15 facing each other, for example, as shown in FIG. These vibrating electrodes 21 and 22 form a piezoelectric resonator 23 together with the piezoelectric substrate 15. The extraction end 21a of the vibration electrode 21 is extracted to the right end of the piezoelectric substrate 15 and is exposed on the surface including the right end surface 11a of the electronic component body 11 (see FIG. 11). The vibration electrode 22
Is pulled out to the left end of the piezoelectric substrate 15 and is exposed on the surface of the electronic component body 11 including the left end face 11b.

The terminal electrode film 12 is electrically connected to a leading end 21a of the vibration electrode 21. Similarly, terminal electrode film 1
4 is electrically connected to the extraction end 22a of the vibration electrode 22. The terminal electrode films 12 to 14 are formed by electroless plating, electroplating, or the like.

As a result, the surface mount type electronic component 60 is
A three-terminal electronic component (oscillator) having an equivalent circuit as shown in FIG. That is, the piezoelectric resonator 23 is connected between the terminal electrode film 12 (input terminal) and the terminal electrode film 14 (output terminal). A capacitance C1 formed between the terminal electrode film 12 and the terminal electrode film 13 (earth terminal) is connected. Further, the terminal electrode film 1
3 and the terminal electrode film 14, a capacitance C2 formed therebetween is connected.

[0006]

In the conventional surface mount type electronic component 60, as can be seen from FIGS. 11 and 12, the leading ends 21a, 21a of the vibrating electrodes 21, 22 are provided.
2a is exposed on the end faces 11a and 11b of the electronic component body 11. For this reason, when forming the terminal electrodes 12 to 14 by electroless plating or electroplating, the end faces 11a, 11b
The plating film 26 is also formed on the surfaces of the extraction ends 21a and 22a exposed to the outside.

However, since the thickness of the leading ends 21a and 22a is small, the bonding area of the plating film 26 is very small. For this reason, the plating film 26 and the leading ends 21a and 22a
Is small, and the plating film 26 is not
a, 22a. For example, the terminal electrode films 12 to 1
If an impact force is applied during the plating for forming No. 4 or the tension of the molten solder is applied during mounting on the printed circuit board, the plating film 26 is easily peeled off. At this time, FIG.
As shown in FIG. 1, when the peeled plating film 26 comes into contact with, for example, the terminal electrode 13 or the like, the terminal electrode film 12 and the terminal electrode film 1
3 is short-circuited.

Accordingly, an object of the present invention is to provide a highly reliable surface mount electronic component which reliably prevents a short circuit between terminal electrode films due to a film formed by a film forming process such as plating. It is in.

[0009]

In order to achieve the above object, a surface mount type electronic component according to the present invention has a terminal electrode film formed on a surface of an electronic component body by a film forming process. A surface mounting type electronic component in which a lead end of an internal electrode formed inside the electronic component main body is drawn out to a surface of the electronic component main body and is electrically connected to the terminal electrode film; At least one of the mounting surface of the main body and the remaining surface other than the surface facing the mounting surface,
A leading end of the internal electrode is led out, and an exposed part of the leading end is covered with at least one of the terminal electrode film and the protective film. Here, the meaning of “coating” includes a case where only a part of the exposed portion is covered with the terminal electrode film or the protective film.

[0010] The terminal electrode film and the protective film cover the exposed portion of the lead end exposed on the surface of the electronic component body, and are formed by the terminal electrode film and the protective film when the terminal electrode film is formed by a film forming process such as plating. This prevents the formation of a film by plating or the like on the surface of the exposed exposed portion of the drawn-out end. Thus, an unnecessary film that is easily peeled is not formed.

The surface-mounted electronic component according to the present invention has at least two terminal electrode films, and the length of the exposed portion of the lead-out end protruding from the terminal electrode film or the protective film is reduced. The distance between the terminal electrode films is smaller than the distance between the terminal electrode films.

By setting the length of the exposed portion of the leading end as described above, when the terminal electrode film is formed, it is formed on the surface of the exposed portion of the leading end protruding from the terminal electrode film or the protective film. The length of unnecessary film formation is smaller than the distance between adjacent terminal electrode films. Therefore, even if an unnecessary film formed on the exposed portion of the extraction end is peeled off, the peeled film does not cause a short circuit between the adjacent terminal electrode films. As a result, it is not necessary to completely cover the entire exposed portion exposed on the surface of the electronic component body with the terminal electrode film and the protective film.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a surface mount electronic component according to the present invention will be described with reference to the accompanying drawings. In the embodiments, the same components and the same portions are denoted by the same reference numerals.

[First Embodiment, FIGS. 1 and 2] FIG. 1 shows one embodiment of a surface mount type electronic component according to the present invention. The surface-mounted electronic component 10 is obtained by applying the present invention to the surface-mounted electronic component 60 described with reference to FIG.
The surface of the electronic component body 11 has three terminal electrode films 12 to 14 formed by electroless plating or electroplating.

Of the terminal electrode films 12 to 14, the terminal electrode films 12 and 14 are formed so as to go around both ends of the electronic component body 11, respectively. Terminal electrode film 12
And 14 function as an input terminal and an output terminal, respectively. In addition, the terminal electrode film 13 is a terminal electrode 12,
It is formed so as to go around the central part of the electronic component body 11 between 14 and functions as a ground terminal. In FIG. 1, the electronic component 10 has a lower surface 11a of an electronic component main body 11 as a mounting surface on a printed wiring board or the like.

As shown in FIG. 2, vibrating electrodes 31 and 32 are formed on the main surfaces of the piezoelectric substrate 15 facing each other. These vibrating electrodes 31 and 32 are connected to the piezoelectric substrate 15.
Together with this, a piezoelectric resonator 33 is formed. Vibrating electrode 31
Is drawn out to the right side of the piezoelectric substrate 15 and is exposed to the right side of the front and rear side surfaces 11b and 11c of the electronic component body 11 (see FIG. 1). here,
The lead-out end 31a is set back so as not to be exposed on the right end face 11d of the electronic component main body 11, being receded from the right side of the piezoelectric substrate 15. Similarly, the leading end 3 of the vibrating electrode 32
2a is pulled out to the left of the piezoelectric substrate 15 and is exposed to the left of the side surfaces 11b and 11c of the electronic component body 11. Here, the draw-out end 32a is set back so as not to be exposed at the left end 11e of the electronic component body 11 since it is retracted from the left side of the piezoelectric substrate 15.

The terminal electrode film 12 is electrically connected to the leading end 31a of the vibration electrode 31. The terminal electrode film 14 is electrically connected to a leading end 32 a of the vibration electrode 32.

In the electronic component 10 having the above configuration, the exposed portions of the lead ends 31a and 32a exposed on the side surfaces 11b and 11c of the electronic component main body 11 are covered with the terminal electrode films 12 and 14, so that the components such as plating are formed. When the terminal electrode films 12 to 14 are formed by film processing, an unnecessary film that is easily peeled is not formed on the surfaces of the exposed portions of the lead ends 31a and 32a. As a result, it is possible to completely solve the problem of the conventional surface mount electronic component such as a short circuit between the terminal electrode films due to unnecessary peeling of the film.

[Second Embodiment, FIGS. 3 and 4] Another embodiment of the surface mount type electronic component according to the present invention is shown in FIG.
Shown in The surface-mounted electronic component 20 according to the second embodiment includes:
There are two terminal electrode films 23 and 24 formed on the surface of the electronic component body 11 by a film forming process such as plating. The terminal electrode film 23 is formed on the surface including the left end surface 11e of the electronic component body 11, and functions as an input terminal. Also,
The terminal electrode film 24 is formed on the surface including the right end face 11d of the electronic component main body 11, and functions as an output terminal. 3, the lower surface 11a of the electronic component body 11 is a mounting surface for a printed wiring board or the like in FIG.

As shown in FIG. 4, the leading end 31a of the vibrating electrode 31 is led out to the right side of the piezoelectric substrate 15 and is exposed on the right end face 11d of the electronic component body 11 (see FIG. 3). Here, the draw-out end 31a is set back so as not to be exposed on the front side and the rear side 11b, 11c of the electronic component body 11 since it is retracted from the front side and the rear side of the piezoelectric substrate 15. Have been. Similarly, the leading end 32a of the vibration electrode 32 is pulled out to the left side of the piezoelectric substrate 15,
It is exposed on the left end face 11e of the electronic component body 11. Here, the draw-out end 32a is set back so as not to be exposed on the front side and the back side side 11b, 11c of the electronic component body 11 since it is receded from the front side and the back side of the piezoelectric substrate 15. Have been.

The terminal electrode film 23 is electrically connected to the leading end 32a of the vibration electrode 32. The terminal electrode film 24 is electrically connected to the leading end 31a of the vibration electrode 31.

In the electronic component 20 having the above-described structure, the exposed portions of the lead ends 31a and 32a exposed on both end surfaces 11e and 11d of the electronic component body 11 are covered with the terminal electrode films 23 and 24, so that plating or the like is performed. When the terminal electrode films 23 and 24 are formed by the film forming process, an unnecessary film that is easily peeled is not formed on the surfaces of the exposed portions of the lead ends 31a and 32a. Therefore, the surface mount electronic component 2 of the second embodiment
0 can also achieve the same effects as the surface-mounted electronic component 10 of the first embodiment.

Third Embodiment, FIG. 5 FIG. 5 shows still another embodiment of the surface mount type electronic component according to the present invention. In the surface-mounted electronic component 30 of the third embodiment, the electronic component body 41 has a case member 42 made of ceramic.
For example, a piezoelectric resonator (not shown) utilizing thickness-shear vibration is accommodated in the concave portion, and a lid member 43 is adhered to the concave portion opening of the case member 42. Terminal electrode films 44 and 45 are formed on both ends of the electronic component body 41 by film forming processing such as plating. In addition, a terminal electrode film 46 is formed at the center of the electronic component body 41,
Functions as a ground terminal. This electronic component 30
In FIG. 5, the lower surface 41a of the electronic component body 41 is a surface to be mounted on a printed wiring board or the like.

The terminal electrode film 44 is electrically connected to the leading end 48 of the vibration electrode of the piezoelectric resonator. Similarly, the terminal electrode film 45 is also electrically connected to the leading end 49 of the vibration electrode of the piezoelectric resonator. Side surfaces 41b, 4 of electronic component body 41
1c, the leading ends 4 of the vibrating electrodes respectively drawn out
The exposed portions of 8, 49 are covered with terminal electrode films 44, 45.

Surface mounted electronic component 30 of the third embodiment
In the same manner as in the first embodiment, it is possible to completely eliminate the problem of the conventional surface mount electronic component, such as the short circuit between the terminal electrode films due to the unnecessary plating film being peeled off.

[Fourth Embodiment, FIGS. 6 and 7] In the surface-mounted electronic component of the fourth embodiment, only a part of the exposed portion of the leading end is covered with the terminal electrode film. As shown in FIG. 6, the surface-mounted electronic component 40 is
Has three terminal electrode films 12 to 14 formed by a film forming process such as plating.

Of the terminal electrode films 12 to 14, the terminal electrode films 12 and 14 are formed so as to go around both ends of the electronic component main body 11, respectively. Terminal electrode film 12
And 14 function as an input terminal and an output terminal, respectively. In addition, the terminal electrode film 13 is a terminal electrode 12,
It is formed so as to go around the central part of the electronic component body 11 between 14 and functions as a ground terminal. 6, the lower surface 11a of the electronic component body 11 is used as a mounting surface on a printed wiring board or the like in FIG.

As shown in FIG. 7, vibrating electrodes 31 and 32 are formed on the main surfaces of the piezoelectric substrate 15 facing each other. These vibrating electrodes 31 and 32 are connected to the piezoelectric substrate 15.
Together with this, a piezoelectric resonator 33 is formed. Further, dummy electrode films 41 and 42 are formed on both main surfaces of the piezoelectric substrate 15, respectively. The leading end 31a of the vibrating electrode 31 and the dummy electrode film 42 are pulled out to the right side of the piezoelectric substrate 15 and exposed to the right side of the front and rear side surfaces 11b and 11c of the electric component body 11 (see FIG. 6). It is exposed on the right end face 11d. Here, a part of the leading end 31 a and the dummy electrode film 42 is receded from the right side of the piezoelectric substrate 15. Similarly, the leading end 32 of the vibration electrode 32
The “a” and the dummy electrode 41 are drawn out to the left side of the piezoelectric substrate 15, and are exposed on the left side of the side surfaces 11 b and 11 c of the electronic component body 11 and are also exposed on the left end surface 11 e. Here, a part of the leading end 32 a and the dummy electrode film 41 is receded from the left side of the piezoelectric substrate 15.

In the electronic component 40 configured as described above, the lead ends 31a, 32a and the dummy electrode films 41, 42 exposed on the side surfaces 11b, 11c of the electronic component body 11 are covered with the terminal electrode films 12, 14. On the other hand, withdrawal end 31 exposed on both end surfaces 11d and 11e of electronic component body 11
The exposed portions of the a and 32a and the dummy electrode films 41 and 42 are not covered with the terminal electrode films 12 and 14.

Here, the distance between the terminal electrode films 12 and 13 and between the terminal electrode films 13 and 14 is D, and the terminal electrode films 12 and 1
4 and the lengths of the exposed portions of the lead-out ends 31a, 32a and the dummy electrode films 41, 42 are L1, L2, L3.
(See FIG. 6), the conditional expressions L1 <D, L2 <D, L
In order to satisfy 3 <D, the leading ends 31a and 32a and a part of the dummy electrode films 41 and 42 are recessed from the right side of the piezoelectric substrate 15.

By setting the leading ends 31a, 32a protruding from the terminal electrode films 12, 14 and the exposed portions of the dummy electrode films 41, 42 as described above, the terminal electrode films 12 to 14 are formed.
When the film 14 is formed, the lengths of the unnecessary plating films 26 formed on the surfaces of the exposed ends of the leading ends 31 a and 32 a and the dummy electrode films 41 and 42 protruding from the terminal electrode films 12 and 14 are determined by the distance It becomes smaller than D. Therefore, drawer end 3
Unnecessary plating film 26 formed on exposed portions of 1a and 32a
When the terminal electrode films 12 and 13 or the terminal electrode film 1 adjacent to each other are
There is no short circuit between 3 and 14.

The side surfaces 11d, 1 of the electronic component body 11
The lead ends 31a, 32a and the dummy electrode films 41, 42 exposed at 1e do not need to be exposed at three places as in the fourth embodiment, but may be at one place, two places, or four or more places. Is also good. At this time, the lengths of the leading ends 31a, 32a protruding from the terminal electrode films 12, 14 and the exposed portions of the dummy electrode films 41, 42 are set to be shorter than the distance D.

[Fifth Embodiment, FIGS. 8 and 9] As shown in FIG. 8, the surface mount type electronic component 50 of the fifth embodiment
Has two terminal electrode films 23 and 24 formed on the surface of the electronic component body 11 by a film forming process such as plating.

As shown in FIG. 9, the lead-out end 31a of the vibrating electrode 31 and the dummy electrode film 42 are drawn out to the right side of the piezoelectric substrate 15, and are exposed on the right end face 11d of the electronic component body 11 (see FIG. 8). , Front and back side 1
It is exposed to 1b and 11c. Similarly, the leading end 32 a of the vibration electrode 32 and the dummy electrode film 41 are connected to the piezoelectric substrate 1.
5, the left end face 11 of the electronic component body 11
e, and the front and rear side surfaces 11b,
11c.

In the electronic component 50 having the above configuration, the lead ends 31a, 32a and the dummy electrode films 41, 42 exposed on both end surfaces 11e, 11d of the electronic component body 11 are covered with the terminal electrode films 23, 24.

On the other hand, the leading ends 31a, 31 exposed on the side surfaces 11b, 11c on the front side and the back side of the electronic component body 11 are provided.
The exposed portions of 2a and the dummy electrode films 41 and 42 are not covered with the terminal electrode films 23 and 24. Here, the distance between the terminal electrode films 23 and 24 is D, and the terminal electrode films 23 and
The lengths of the protruding ends 31a, 32a and the exposed portions of the dummy electrode films 41, 42 protruding from the L24 are L4, L5 (FIG. 8).
), The conditional expressions L4 <D and L5 <D are satisfied.

By setting the exposed ends 31a and 32a protruding from the terminal electrode films 23 and 24 and the exposed portions of the dummy electrode films 41 and 42 as described above, the terminal electrode films 23 and 24 are formed.
When the film 24 is formed, the lengths of the unnecessary plating films 26 formed on the surfaces of the exposed portions of the leading ends 31 a and 32 a and the dummy electrode films 41 and 42 protruding from the terminal electrode films 23 and 24 are determined by the distance It becomes smaller than D. Therefore, drawer end 3
Unnecessary plating film 26 formed on exposed portions of 1a and 32a
Even if the terminal electrode films 23 and 24 are peeled off, the terminal electrode films 23 and 24 adjacent to each other are not short-circuited by the peeled plating film 26.

Sixth Embodiment, FIG. 10 As shown in FIG. 10, the surface-mounted electronic component 55 has a protection film 56 and terminal electrode films 12 and 14 covering the exposed portions of the internal electrodes. 9 on the piezoelectric substrate 15 of the fifth embodiment.
The vibrating electrodes 31, 32 and the dummy electrode film 41,
42 are formed.

End faces 11d and 11 of electronic component body 11
A protective film 56 made of resin is formed on the entire surface of e before the terminal electrode films 12 and 14 are formed. The terminal electrode films 12 and 14 and the protective film 56 are connected to the side surfaces 11b and 11c and the end surfaces 11d and 11e of the electronic component body 11.
The entirety of the exposed portions 31a and 32a of the vibrating electrodes 31 and 32 and the exposed portions of the dummy electrode films 41 and 42 are covered.

With such a configuration, the electronic component body 1
1 and the leading ends 31a, 32a and the dummy electrode film 4 exposed on the side surfaces 11b, 11c and the end surfaces 11d, 11e.
The exposed portions of the terminal electrode films 12 and 14 and the protective film 5
6, the terminal electrode film 1 is formed by plating.
When forming the second and the second, an unnecessary plating film that is easily peeled is not formed on the surfaces of the exposed portions of the extraction ends 31a and 32a and the dummy electrode films 41 and. Thus, it is possible to solve the problem of the conventional surface mount electronic component, such as a short circuit between the terminal electrode films due to unnecessary peeling of the plating film.

[Other Embodiments] The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist. In particular, the present invention can be applied not only to piezoelectric components but also to inductors and capacitors.

[0042]

As is clear from the above description, according to the present invention, since the exposed portion of the lead-out end of the internal electrode is covered with the terminal electrode film and the protective film, the film forming process such as plating is performed. When the terminal electrode film is formed by the method described above, a film formed by unnecessary plating or the like that is easily peeled is not formed on the surface of the exposed portion of the extraction end. Therefore, a short circuit between the terminal electrode films due to unnecessary peeling of the film can be eliminated, and a highly reliable surface mount electronic component can be obtained.

Further, according to the present invention, by appropriately setting the length of the exposed portion of the lead-out end, when the terminal electrode film is formed, the lead-out end protruding from the terminal electrode film or the protective film is formed. The length of the unnecessary film formed on the surface of the exposed portion can be made smaller than the interval between the terminal electrode films, and the short circuit between the terminal electrode films is reliably prevented by the terminal electrode film or the protective film having a small area. be able to.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing an electrode configuration of a piezoelectric substrate used in the surface-mounted electronic component shown in FIG.

FIG. 3 is a perspective view of a second embodiment of the surface mount electronic component according to the present invention.

FIG. 4 is a perspective view showing an electrode configuration of a piezoelectric substrate used in the surface-mounted electronic component shown in FIG.

FIG. 5 is a perspective view of a third embodiment of the surface-mounted electronic component according to the present invention.

FIG. 6 is a perspective view of a fourth embodiment of the surface-mounted electronic component according to the present invention.

FIG. 7 is a perspective view showing an electrode configuration of a piezoelectric substrate used in the surface-mounted electronic component shown in FIG.

FIG. 8 is a perspective view of a fifth embodiment of the surface-mounted electronic component according to the present invention.

FIG. 9 is a perspective view showing an electrode configuration of a piezoelectric substrate used in the surface mount electronic component shown in FIG.

FIG. 10 is a perspective view of a sixth embodiment of the surface-mounted electronic component according to the present invention.

FIG. 11 is a perspective view of a conventional surface mount electronic component.

FIG. 12 is a perspective view showing an electrode configuration of a piezoelectric substrate used in the surface-mounted electronic component shown in FIG.

FIG. 13 is an equivalent circuit diagram of the surface mount electronic component shown in FIG. 11;

[Explanation of symbols]

10, 20, 30, 40, 50, 55: Surface-mount type electronic component 11, 41: Electronic component body 11a, 41a: Mounting surface 11b, 11c, 41b, 41c: Side surface 11d, 11e: End surface 12-14, 44- 46: terminal electrode film 31, 32: vibrating electrode (internal electrode) 41, 42: dummy electrode film (internal electrode) 31a, 32a, 48, 49: leading end 56: protective film

Claims (2)

[Claims] 1. An electronic component body having a terminal electrode film formed by a film forming process on a surface of the electronic component body, and a leading end of an internal electrode formed inside the electronic component body being connected to a surface of the electronic component body. In a surface-mounted electronic component that is drawn out and electrically connected to the terminal electrode film, the internal electrode is provided on at least one of a mounting surface of the electronic component body and a remaining surface other than a surface facing the mounting surface. Wherein the lead-out end is drawn out, and an exposed portion of the lead-out end is covered with at least one of the terminal electrode film and the protective film. 2. The semiconductor device according to claim 1, further comprising: at least two terminal electrode films, wherein a length dimension of an exposed portion of the terminal electrode film or the leading end protruding from the protective film is smaller than a distance between the terminal electrode films. The surface-mounted electronic component according to claim 1.