JPH0722276A - Chip device - Google Patents

Abstract

PURPOSE:To provide a chip device in which the toom stone phenomenon can be prevented at the time of mounting a device by employing outer terminals having identical profile and equalizing the width and area of both outer terminals. CONSTITUTION:A cathode layer 3 is provided on the peripheral surface of a pressure molded capacitor element 1 planted with an anode lead, and a plating layer 5 is applied on the end face of the cathode layer 3 through a conductor layer 4 and a metal plating layer thus forming an outer terminal. An outer terminal 16 of tin plate, for example, having same width as the cathode side outer terminal is welded t an anode lead and then the peripheral surface of the element is molded of an exterior resin 2 such that the outer terminals 5, 6 have identical width and area. Since both outer terminals 5, 6 have identical width and area, the toom stone phenomenon due to the differential moment of molten solder 7 can be prevented at the time of mounting a device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type electronic component having a small size and a large capacity, and more particularly to a chip type electronic component suitable for application to a reflow soldering apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, this type of chip-type electronic component is shown in FIG.
As shown in (a) and (b), a cathode layer 3 is provided on the peripheral surface of a capacitor element 1 formed by embedding and pressure-molding an anode lead, and an insulating exterior resin 2 having an insulating property is formed on the peripheral surface. Then, on the anode lead side and the cathode layer end face, solder plating 5 is applied via the conductor layer 4 and the metal plating layer to form external terminals.

There are various sizes of such chip type electronic parts. For example, a chip type electronic part called 3216 type has a size of 3.2 × 1.6 mm, and is mainly mounted on a substrate by a reflow method. Is used.

[0004]

By the way, as described above, when a chip type electronic component is mounted on a printed circuit board by the reflow method, one of the electrodes floats up from the substrate and becomes vertical (Manhattan or tombstone phenomenon). Is called) occurs.

The cause of the tombstone phenomenon is that in the conventional electrode structure, the terminal shape on the anode lead side is a convex portion, which is different from the terminal shape on the cathode side, so that the surface tension due to the solder melted during mounting becomes uneven on the left and right. . Since this difference in surface tension generates a moment that raises the component body,
Tombstone phenomenon occurs.

The tombstone phenomenon is more likely to occur because the solder surface tension relative to the weight of the component becomes relatively larger as the component becomes smaller.

Further, as a method for preventing the tombstone phenomenon, as described in Japanese Utility Model Application Laid-Open No. 63-193826, only the upper side of the electrode portion is transferred or screen-printed to form a solder resistance layer and added to the left and right terminals. Although a method for reducing the moment is used, when the left and right terminal shapes are not uniform as in the conventional chip-type electronic component, the left and right terminals are disclosed by the method described in Japanese Utility Model Laid-Open No. 63-193826. It is difficult to eliminate the difference in the moment applied to.

[0008]

In order to solve the above-mentioned problems, in the present invention, in a chip type capacitor in which a cathode layer 3 is provided on the peripheral surface of a capacitor element 1 in which an anode lead is led, a conductive property is applied to an end surface thereof. Body layer 4 An external terminal is formed by applying a solder plating layer 5 via a metal plating layer, and one anode lead has the same width as the external terminal on the cathode side. × 0.3m
The external terminal 6 is formed by welding a metal plate such as a tin plate processed into an L-shape or a trapezoid so that the terminal width and area of the external terminal exposed to the outside are constant (for example, 3216 type). If it is about 1.2 × 0.3 mm), the upper side of the external terminal and the element peripheral surface are molded with the exterior resin 2.

[0009]

The external terminal 6 on the side of the anode lead is formed into a metal plate having the same width as the other external terminal 5 and is packaged as described above. It can be formed in the same shape and terminal width.

As a result, the molten solder 7 adheres only to the electrode portions having the same area on the bottom surface side, so that there is no difference in the moment 9 applied to the external terminals 5 and 6 due to the melting of the solder 7. This prevents the tombstone phenomenon caused by the difference between the moments 9 applied to the left and right external terminals 5 and 6.

[0011]

The present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention, a sectional view taken along the line AB of FIG. 1A, and a mounting state diagram.

In FIG. 1, the capacitor element 1 is formed by pressing a similar metal powder around a metal wire having a valve action into a prismatic shape, and vacuum-sintering the metal powder with an oxide layer, a semiconductor layer, and a graphite layer. And a cathode layer 3 having an electrode lead layer is formed.

Next, a conductor layer 4 is formed on the end face of the cathode layer 3 in a different direction from the capacitor element 1, and a solder plating layer 5 is formed on the conductor layer 4 via a metal plating layer to form external terminals. A metal plate, such as a tin plate, which is formed into an L-shaped or trapezoidal shape so that the anode lead has the same width as the external terminal on the cathode side (for example, about 1.2 × 0.3 mm for the 3216 type). The external terminal 6 is welded.

Next, the external terminals 5 and 6 exposed to the outside have the same terminal width and area (for example, 321).
If it is a 6-inch type, it will be 1.2 x 0.3 mm), the external terminal 5,
The chip-type electronic component is constructed by molding the upper side of 6 and the peripheral surface of the element with the exterior resin 2 using a method such as potting or casting.

[0016]

As described above, according to the present invention, the external terminal 6 on the anode lead side is a metal plate having the same width and area as the other external terminal 5, and the exterior resin 2 is molded as described above. There is an effect that the terminal shape on the anode side, which is conventionally convex, can be formed into a terminal width similar to the terminal shape on the cathode side.

As a result, the solder 7 which is melted at the time of mounting the components adheres only to the electrode portions having the same area on the bottom surface side, and the moment 9 applied to both the external terminals 5 and 6.
It is possible to prevent the difference between the two and to prevent the tombstone phenomenon. Further, since the peripheral surface of the element is formed flat with the exterior resin 2, there is an effect that the reliability (mounting efficiency) at the time of mounting the component can be improved from 99.95% of the conventional example to 99.999%.

[Brief description of drawings]

FIG. 1 is a perspective view (a) of a chip-type electronic component according to an embodiment of the present invention, a cross-sectional view (b) taken along the line AB of FIG. 1 (a), and a mounting state view (c).

2A is a perspective view of an example of a conventional chip-type electronic component, FIG. 2A is a cross-sectional view taken along line AB of FIG. 2A, and FIG.

FIG. 3 is a mounting state diagram showing a tombstone phenomenon in an example of a conventional chip-type electronic component.

[Explanation of symbols]

 1 Capacitor element 2 Exterior resin 3 Cathode layer 4 Conductor layer 5 Solder plating layer 6 External terminal 7 Solder 8 Land 9 Moment (surface tension)

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01G 9/08 // H05K 1/18 K 7128-4E H01G 9/05 C 9/08 C

Claims (2)

[Claims] 1. A chip-type capacitor in which a cathode layer is provided on the peripheral surface of a capacitor element from which an anode lead is led, a soldered external terminal is formed on an end surface of the capacitor element through a conductor layer and a metal plating layer. The anode lead is processed to have the same width as the external terminal on the cathode side, a metal plate is welded to form the external terminal, and the upper side of these external terminals and the element peripheral surface are covered with resin. Chip type electronic components 2. The resin outer package is characterized in that the left and right electrode terminals obtained by different forming methods are formed on the upper side of the external terminal and the element peripheral surface so that the terminal width and area are constant. The chip-type electronic component according to claim 1.