JP2002280254A - Surface mounting type stacked ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a ceramic electronic component, so that it can be soldered accurately, fitting the direction of mounting, the attitude, etc., to the land parts of a wiring, even if it is a component of very small form. SOLUTION: External electrodes 11 and 12, which display circular form where the inner end fringe positioned within the plane from the end fringe of a ceramic element assembly 10 becomes its apex at the center in the width direction of the ceramic element assembly 10, are made, and they are soldered, fitting the direction of the mounting, the attitude, etc., to the lands 13 and 14 of the wiring pattern by the self alignment effect by which the fused solder is concentrated on the apex to which the distance is long.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type multilayer ceramic electronic component mainly including a multilayer ceramic capacitor, and more particularly, to a case where the multilayer ceramic electronic component is surface-mounted on a board surface of a circuit board by soldering external electrodes. And to improve the self-alignment effect.

[0002]

2. Description of the Related Art In general, a multilayer ceramic electronic component comprises a multilayer ceramic body 1 formed by alternately laminating a plurality of internal electrodes and ceramic layers as shown in FIG. It is constituted by providing at both ends of the ceramic body 1. External electrodes 2 and 3
Is formed such that an inner edge located in a plane from an edge of the multilayer ceramic body 1 has a linear shape in the width direction.

[0003] The multilayer ceramic electronic component has been reduced in size to a surface mount type component as electronic devices and the like have become smaller. For example, multilayer ceramic capacitors used in high- and low-voltage integrated circuits are also required to be miniaturized to have a length of about 0.6 mm and a width of about 0.3 mm.

The multilayer ceramic electronic component is surface-mounted on the board surface of the circuit board by fixing each external electrode to the land portion of the wiring pattern by soldering. It is difficult to accurately fix by soldering the posture etc. according to the land of the wiring pattern.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a surface-mounted multilayer ceramic electronic device in which the mounting orientation and posture can be accurately fixed by soldering in accordance with the land portion of the wiring pattern, even in a very small form. The purpose is to provide parts.

[0006]

According to a first aspect of the present invention, there is provided a surface mount type multilayer ceramic electronic component, wherein an inner edge located in a plane from an edge of the multilayer ceramic body is formed of the multilayer ceramic body. It is configured by forming an external electrode having an arc shape that becomes a vertex at the center in the width direction.

In the surface-mounted multilayer ceramic electronic component according to a second aspect of the present invention, the distance from the edge of the multilayer ceramic body to the base point of the inner edge located in the plane is 150 μm.
m, and the distance from the base point of the inner edge to the vertex is 3
It has a distance of 0-100 μm and a total of 180-25
It is constituted by forming an external electrode having a height of 0 μm.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be widely applied to forming external electrodes of multilayer ceramic electronic components such as multilayer ceramic capacitors, multilayer ceramic inductors, multilayer varistors and the like. Description will be made based on the case where a capacitor is formed.

The multilayer ceramic capacitor is composed of Pd, P
By printing an internal electrode on a dielectric green sheet with a conductive paste using a noble metal such as t or Ag / Pd or a base metal such as Ni, and alternately laminating a plurality of the dielectric green sheets with the internal electrode, as shown in FIG. As shown in the figure, the multilayer capacitor body 10 is formed, and external electrodes 11 and 12 that are electrically connected to the internal electrodes are provided at both ends.

The external electrodes 11 and 12 are connected to the internal electrodes and are connected to both ends of the multilayer capacitor body 10 by Ag.
/ Pd or Cu base electrode layer, an intermediate Ni plating layer deposited on the base electrode layer, and an outermost Sn or alloy-based alloy plating layer deposited on the Ni plating layer And are formed in layers.

The external electrodes 11 and 12 are formed such that an inner edge located in a plane from an edge of the multilayer capacitor body 10 has an arc shape having a vertex at the center in the width direction of the multilayer capacitor body 10. Have been. This electrode shape forms the electrode surface on the side opposite to the land portion of the wiring pattern.
If the orientation is not limited, the top and bottom can be formed to have the same shape.

The external electrodes 11 and 12 are located within a plane from the end edge of the multilayer capacitor body 10 when a very small multilayer ceramic capacitor having a length of about 0.6 mm and a width of about 0.3 mm is exemplified. 150 to the starting point of the inner edge
An external electrode having a distance (a) of μm, a distance (b) from 30 to 100 μm from the base point of the inner edge to the vertex, and a total height (c) of 180 to 250 μm is formed. Good to do.

In the multilayer ceramic capacitor constructed as described above, cream solder is applied to the lands of the wiring pattern, and the external electrodes 11 and 12 are placed in alignment with the lands 13 and 14 of the wiring pattern as shown in FIG. Thereafter, when the cream solder is melted, the melted solder rises in the plane along the inner edge of the arc while pushing up the multilayer capacitor body 10.

The tension of the solder concentrates on the vertex of the inner edge located in a plane from the edge of the multilayer capacitor body 10 having a long distance. Therefore, the land portion 1 of the wiring pattern
When placed on the bases 3 and 14, even if a shift shift in the θ direction occurs as shown in FIG. 3 or a horizontal shift occurs from a predetermined position as shown in FIG. Due to the self-alignment effect, soldering and fixing can be performed accurately in accordance with the land portions 13 and 14 of the wiring pattern.

In place of the arc-shaped inner edge described above,
The multilayer ceramic body may be formed in a non-linear shape exhibiting an oblique side such as an isosceles which is a vertex at the center in the width direction. However, compared to the hypotenuse, the arc-shaped one is more suitable for soldering and mounting very small multilayer ceramic capacitors because the upward flow of molten solder occurs smoothly along the inner edge of the arc. The self-alignment effect can be more effectively exerted.

In order to confirm its effectiveness, a length of 0.6 m
m, 0.3mm wide multilayer ceramic capacitor.
As shown in the figure, a distance (a) of 150 μm from the end edge of the multilayer capacitor element body 10 to the base point of the inner edge located in the plane, and the distance from the base point of the inner edge to the vertex is 30 μm.
Having a distance (b) of １００100 μm, and
External electrode having a height (c) of 250 μm (sample No. 2)
To 7).

As a comparative example, the distance from the base point of the inner edge to the vertex has a distance (b) of 20 μm, and the total distance is 170 μm.
An external electrode (sample No. 1) having a height (c) of m is formed, and a distance (b) from the base point of the inner edge to the apex is 110 μm, and a height (c) of 260 μm as a whole
An external electrode (Sample No. 8) having the following was formed, and soldering was carried out in a state where each sample was laterally shifted by 80 μm from a predetermined position as shown in FIG.

[0018]

[Table 1]

As is clear from Table 1, in the case of the sample 1, since the distance (b) from the base point of the inner edge to the apex was small, about 1.7% of defective adhesion was observed. On the other hand, in the case of sample 8, the distance from the base point of the inner edge to the vertex (b)
Of about 2.2%. This depends on the relationship between the height of the arc and the upward flow of the molten solder. However, from the viewpoint of the rate of defective fixation, it is suppressed to be lower than in the conventional example. On the other hand, Sample Nos. 2 to 7 of the present invention
It has been found that the sample can be soldered and fixed 100% normally.

[0020]

As described above, according to the surface mount type multilayer ceramic electronic component of the first aspect of the present invention, the inner edge located within a plane from the edge of the multilayer ceramic body has the multilayer ceramic element. Since the external electrode is formed in the shape of an arc that becomes the vertex at the center in the width direction of the body, the self-alignment effect that the molten solder concentrates on the vertex with a long distance allows the mounting orientation, posture, etc., even for extremely small parts. It can be soldered and fixed accurately according to the land of the wiring pattern.

According to the surface mount type multilayer ceramic electronic component of the present invention, the distance from the edge of the multilayer ceramic body to the base point of the inner edge located in the plane is 150 μm.
And the distance from the base point of the inner edge to the vertex is 30
距離 100 μm, 180 to 250 as a whole
By forming an external electrode having a height of μm, 100% normal soldering and fixing can be achieved even with a component having an extremely small form by a self-alignment effect in which molten solder is concentrated on a vertex having a long distance.

[Brief description of the drawings]

FIG. 1 is a plan view showing a surface-mounted multilayer ceramic electronic component according to the present invention.

FIG. 2 is an explanatory view showing a self-alignment effect of the surface-mounted multilayer ceramic electronic component according to the present invention.

FIG. 3 is an explanatory view showing a mounting displacement according to an example of a surface-mounted multilayer ceramic electronic component.

FIG. 4 is an explanatory view showing a mounting displacement according to another example of the surface-mounted multilayer ceramic electronic component.

FIG. 5 is a plan view showing a surface mount type multilayer ceramic electronic component according to a conventional example.

[Explanation of symbols]

 Reference Signs List 10 multilayer ceramic body 11, 12 external electrode 13, 14 land part of circuit board

Claims (2)

[Claims] A ceramic body formed by alternately laminating a plurality of internal electrodes and ceramic layers; external electrodes electrically connected to the internal electrodes are provided at both ends of the multilayer ceramic body; In a surface-mounted multilayer ceramic electronic component in which the electrodes are fixed to the land of the wiring pattern by soldering and mounted on the board surface of the circuit board, the inner edge located within a plane from the edge of the multilayer ceramic body is laminated A surface-mounted multilayer ceramic electronic component characterized by forming an external electrode having an arc shape having a vertex at the center in the width direction of a ceramic body. 2. The laminated ceramic body has a distance of 150 μm from an end edge to a base point of an inner edge located in a plane, and a distance from the base point of the inner edge to a vertex of 30 to 100 μm.
2. The surface-mounted multilayer ceramic electronic component according to claim 1, wherein external electrodes having a distance of m and an overall height of 180 to 250 μm are formed.