JPH1131604A - Surface-mounted part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check a contact between an element and a chemical substance such as solder or flux during soldering to thereby prevent changes in the electrical properties of a part by providing an inner element of the part and a protective layer on an outer peripheral surface, excluding the terminal electrode portions of the element and by curving the protective layer toward terminal electrode surfaces. SOLUTION: A protective layer 1 is curved inward towards the surfaces of terminal electrodes. Terminal electrodes 2 are formed on the both ends of the layer 1. A plurality of inner electrodes 4 are formed inside a ceramic element 3 that is mainly composed of ZnO. The terminal electrodes 2 are formed by applying and baking an Ag-Pd paste onto the both ends of the element 3. The layers 1 made of an insulting butyl rubber and formed outside both electrodes 2 to thickness, ranging from 20 to 30 μm. Thus, a surface-mounted part has the upper and lower surfaces and side surfaces of the element 3, excluding the terminal electrode portions covered with the layers 1. In addition, the junction between the layer 1 and each electrode 2 has a width of 20 μm or more, and thus has extremely high contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount component.

[0002]

2. Description of the Related Art These surface mount components are connected to a mounting board or the like by soldering an electrode layer formed at an end thereof.

Conventionally, the terminal electrode portion is formed by applying a conductive metal paste and firing it.

[0004]

In the above-mentioned conventional surface mount components, elements are exposed except for terminal electrode portions.

[0005] For this reason, there is a problem that electrical characteristics change when soldering to a mounting board or the like.

Further, even if soldering is performed, there is a problem that the connection between the terminal electrode portion and the mounting board or the like becomes insufficient and unstable.

[0007] When soldering these conventional surface mount components to a mounting board or the like, in order to prevent the influence of soldering from spreading from the exposed portion of the element, the surface mount components are individually processed in a different manner from peripheral components. I had to.

[0008] This is a method that does not involve economy in a process requiring high-density mounting.

In order to secure a sufficient and stable connection, more careful processing must be performed.

[0010]

The present invention has been made in view of the above problems, and as a result of intensive studies on forming a protective layer on a surface mount component and forming a plating layer on a terminal electrode, the present invention has been completed. Is completed.

That is, as shown in FIGS. 1 and 3, the present invention has a protective layer on the inner surface of a surface-mounted component and an outer peripheral surface excluding a terminal electrode portion of the device. It is intended to provide a surface mount component characterized by performing the following.

The protective layer in the present invention is not particularly limited as long as it is a member having an insulating property, but rubbers such as butyl rubber, ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, nitrile rubber, and fluorine rubber are used. And resins such as polyvinylidene chloride, ethylene-vinyl acetate copolymer, fluorine resin represented by ethylene tetrafluoride, polyphenylene oxide, and polyester elastomer.

Further, as the protective layer, B, Si, Ba,
Insulating glasses containing at least one of the elements of Ti or their oxides are also suitable.

Further, the protective layer has a thickness of 10 to 100 μm.
Is a preferable condition for protecting the element.

[0015]

[Operation] With the above structure, the protective layer formed in the form of a film prevents contact between the element and a chemical substance such as solder or flux during soldering. Changes in dynamic characteristics can be prevented.

On the other hand, in order to facilitate soldering, in a process for forming a plating layer on a terminal electrode portion,
The protective layer acts as an acid-resistant masking.

By curving the protective layer inward, the protective layer can be sufficiently secured particularly on the side of the electrode where the plating solution is most likely to enter. It is possible to prevent alteration, prevent a change in electrical characteristics, and obtain a plating layer having a predetermined shape, so that a sufficient and stable connection can be ensured in soldering to a mounting board or the like. .

Further, since the protective layer is curved with respect to the terminal electrode surface, the electrode surface is enlarged in the plane direction, so that better soldering is possible.

An object of the present invention is to provide a surface mount component which is generally inexpensive and has excellent reliability.

[0020]

FIG. 1 is a plan view of a surface mount component according to the present invention.

Reference numeral 1 denotes a protective layer which is curved inward with respect to the terminal electrode surface.

Terminal electrodes 2 are formed at both ends.

FIG. 2 is a sectional view of a surface mount component according to the present invention.

Reference numeral 3 denotes a ceramic element containing ZnO as a main component, and a plurality of internal electrodes 4 are formed inside the element.

At both ends of the ceramic element 3, terminal electrodes 2 are formed by applying and baking an Ag-Pd paste, and a protective layer 1 of insulating butyl rubber having a thickness of 20 It is formed in a thickness of 30 μm.

With the above structure, in the surface mount component according to the present invention, the upper and lower surfaces and side surfaces of the ceramic element 3 excluding the terminal electrode portion are covered with the protective layer 1.

Moreover, the bonding portion between the protective layer 1 and the terminal electrode 2 has a surface structure with a width of 20 μm or more, has extremely high adhesion, and prevents contact between the ceramic element 3 and a chemical substance such as solder or flux. Therefore, deterioration of the element can be reliably prevented.

[0028]

Embodiment 2 FIG. 3 is a plan view of a surface mount component according to the present invention.

Reference numeral 11 denotes a protective layer which is curved inward with respect to the terminal electrode surface. At both ends, terminal electrodes on which the plating layer 15 is formed are formed.

FIG. 4 is a sectional view of a surface mount component according to the present invention.

Reference numeral 13 denotes a ceramic element containing ZnO as a main component, and a plurality of internal electrodes 14 are formed inside the element.

At both ends of the ceramic element 13, terminal electrodes 12 are formed by applying and baking an Ag paste, and a protective layer 11 of insulating butyl rubber having a thickness of 20 to 30 μm is formed on the outside of both. It is formed with.

A plating layer 15 having a thickness of 5 to 20 μm is formed on the exposed portion of the end electrode 12.

The plating layer 15 is a double layer of the inner Ni layer 15a and the outer Sn-Pb layer 15b.

With the above structure, the surface mounting component according to the present invention has the terminal electrode 12 on which the plating layer 15 is formed.

In addition, the protective layer 11 is
Since the terminal electrode 12 is curved inward, the terminal electrode 12 is enlarged in the plane direction.
A sufficient and stable connection can be secured.

[0037]

According to the present invention, the following effects can be obtained.

1. Since contact between the element and a chemical substance such as solder or flux in soldering is prevented, deterioration of the element can be prevented, and a change in electrical characteristics can be prevented.

2. Since the contact between the plating solution and the element is mainly hindered in the plating process, deterioration of the element can be prevented, and a change in electrical characteristics can be prevented.

3. Since a plating layer having a predetermined shape can be obtained, sufficient and stable connection can be ensured in soldering to a mounting board or the like.

4. Since the protective layer is curved with respect to the terminal electrode surface, the electrode surface is enlarged in the plane direction, so that better soldering is possible.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line XX of the surface mount component of FIG.

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

FIG. 4 is a sectional view taken along line YY of the surface mount component of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective layer 2 Terminal electrode 3 Ceramic element 4 Internal electrode 11 Protective layer 12 Terminal electrode 13 Ceramic element 14 Internal electrode 15 Plating layer 15a Ni layer 15b Sn-Pb layer

Claims (5)

[Claims] 1. A surface mounting device comprising: an internal element of a surface mount component; and a protective layer on an outer peripheral surface excluding a terminal electrode portion of the element, wherein the protective layer is curved with respect to a terminal electrode surface. parts. 2. The protective layer is made of butyl rubber having an insulating property.
2. The surface mount component according to claim 1, wherein the component is made of rubber such as ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, nitrile rubber, and fluoro rubber. 3. The protective layer is made of an insulating polyvinylidene chloride, an ethylene / vinyl acetate copolymer, a fluorine resin represented by ethylene tetrafluoride, polyphenylene oxide,
The surface mount component according to claim 1, which is made of a resin such as a polyester elastomer. 4. The surface mount component according to claim 1, wherein the protective layer is made of an insulating glass containing at least one of B, Si, Ba, and Ti elements or oxides thereof. 5. The surface mount component according to claim 1, wherein a plating layer is formed on the terminal electrode portion.