JPH11251176A - Ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an on-board ceramic electronic component from being damaged by stress due to the expansion or shrinkage of a wiring board through the changes in temperature. SOLUTION: A chip-shaped ceramic electronic component 12 is provided with terminal electrodes 21 at both ends. Terminal members 13 constituted of metal plates are connected to the terminal electrodes 21. Surfaces 28 lacking affinity for solder are formed on parts faced inside and protruding from connecting parts of the terminal members 13 to the terminal electrodes 21. A solder 30 for joint is prevented from rising along the surfaces faced inside of the terminal members 13 up to the electronic component 12 due to action of the surfaces 28 lacking affinity for the solder. Accordingly, deformation or action of the terminal members 13 for reducing stress will not be blocked by the solder 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic electronic component, and more particularly to a structure of a terminal portion of a ceramic electronic component having a chip-shaped ceramic electronic component body such as a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art For example, when a ceramic electronic component such as a multilayer ceramic capacitor is mounted on a wiring board made of aluminum having excellent heat dissipation, a difference in thermal expansion between the aluminum substrate and the ceramic electronic component is large.
In a temperature cycle in which the temperature is repeatedly increased and decreased, there is a problem that the ceramic electronic component is likely to be broken. In particular, in the case of a multilayer ceramic capacitor using a high-capacity Pb-based ceramic dielectric required in the power supply market, this problem is more likely to occur because its bending strength is relatively low.

In order to solve the above problem, a ceramic electronic component 1 having a structure as shown in FIG. 5 has been proposed and put to practical use. The ceramic electronic component 1 shown in FIG. 5 includes, for example, two chip-shaped ceramic electronic component main bodies 2 constituting a multilayer ceramic capacitor, and terminal electrodes 3 are formed at both ends of each electronic component main body 2. I have. These electronic component bodies 2 are stacked up and down, and are joined to each other by an adhesive (not shown).

[0004] Each terminal electrode 3 of two electronic component bodies 2
The terminal member 4 is commonly attached to the terminals. More specifically, the terminal member 4 is configured by a metal plate. One end of the terminal member 4 is bent with respect to its base, whereby the connection terminal portion 6 to the wiring board 5 indicated by an imaginary line is formed.
Is formed. The terminal member 4 has a connection terminal portion 6
Each terminal electrode 3 is located at the base of the electronic component body 2 at the base thereof so as to face the downward side surface 7 of the electronic component body 2 located below.
Connected to. Although not shown, a conductive bonding material such as solder or a conductive adhesive is used for this connection.

[0005] The ceramic electronic component 1 is mounted by soldering the connection terminal portions 6 of the terminal members 4 to the wiring board 5 with solder 8. In order to enable such soldering, the metal plate for the terminal member 4 is formed of a metal having good solderability, or at least a metal which has been treated so as to provide a solder affinity surface which is compatible with solder on the surface. .

[0006]

However, the purpose of attaching the terminal members 4 is to absorb the stress generated due to the expansion and contraction of the wiring board 5 due to the temperature change due to the deformation or movement of the terminal members 4, and Despite trying to prevent the component body 2 from being destroyed by thermal shock, the solder 8 applied for mounting is
Such a behavior may be contrary to the purpose.

That is, the solder 8 is not only applied to the surface of the terminal member 4 facing the outside as shown in FIG. 5, but also the portion of the terminal member 4 which protrudes from the connection portion to the terminal electrode 3. The solder 8 is also provided on the surface facing inward, and the latter solder 8 rises along the terminal member 4 having a surface having good solderability, and may reach the terminal component body 2.

For this reason, the solder 8 directly connects the terminal electrode 3 and the wiring board 5, and the deformation or movement of the terminal member 4 for absorbing the stress caused by the expansion and contraction of the wiring board 5 due to the temperature change. In this case, the purpose of providing the terminal member 4 for preventing the electronic component body 2 from being broken by thermal shock may not be properly achieved.

Further, the solder 8 gives a thermal shock to the electronic component main body 2, whereby the electronic component main body 2 is destroyed. In some cases, stress that may cause destruction may be applied to the electronic component body 2. These problems are particularly caused by the use of an aluminum substrate having a large thermal expansion coefficient as the wiring board 5 or the use of the electronic component main body 2 having a relatively low bending strength such as a multilayer ceramic capacitor using a Pb-based ceramic dielectric. It is more serious when preparing.

In order to solve the above-mentioned problem, it is effective to increase the length of the portion of the terminal member 4 that protrudes from the portion connected to the terminal electrode 3. However, when such a solution is adopted, a problem is encountered that the terminal member 4 is easily deformed when the electronic component body 2 receives the force 9 from the side. When the terminal member 4 is deformed in this way, the terminal member 4
Contacting or approaching the above undesired portion, or contacting or approaching another electronic component, causes variation in electrical characteristics or short-circuit failure.

Further, when the length of the protruding portion of the terminal member 4 is increased, the mounting height is increased, and a problem that the volume mounting density is reduced is caused. Accordingly, an object of the present invention is to provide a ceramic electronic component that can solve the above-described problems.

[0012]

SUMMARY OF THE INVENTION The present invention is directed to a chip-shaped ceramic having two opposite end faces and a side face connecting the two end faces, and having at least a terminal electrode formed on each end face. An electronic component body and a metal plate, one end of which is bent with respect to the base to form a connection terminal portion to the wiring board, and the connection terminal portion faces the side surface of the electronic component body. A terminal member connected to each terminal electrode at a base portion so as to be positioned, and is directed to a ceramic electronic component, and is opposed to at least a side surface of the connection terminal portion in order to solve the technical problem described above. The surface is characterized in that a solder non-affinity surface that is not compatible with solder is formed.

In a preferred embodiment according to the present invention, the following configuration is employed to provide the above-mentioned solder non-affinity surface. In other words, the metal plate constituting the terminal member is made of a metal that provides a surface having poor solderability, and the non-solder compatible surface is provided by the surface itself of the metal plate.
A solder-affinity layer is formed on at least a portion of the terminal member that protrudes from a portion connected to the terminal electrode and faces outward, in order to provide a solder-affinity surface that is compatible with solder.
The solder affinity layer can be formed, for example, by applying a metal such as solder, Ag, Au, or Sn to the surface of the metal plate by plating or the like.

[0014] In the present invention, it is preferable that the non-solder compatible surface of the terminal is a portion of the terminal member protruding from a portion connected to the terminal electrode and is formed on the entire surface or almost the entire surface facing inward. In the present invention, the terminal member may include a shelf-like portion formed by bending a part of the metal plate to receive the side surface of the electronic component body facing the connection terminal portion.

As described above, when a shelf portion is provided, it is preferable that the surface of the shelf portion facing the connection terminal is also formed with a solder non-affinity surface. Further, in the present invention, it is preferable that no terminal electrode is formed on the side surface of the electronic component body facing the connection terminal portion. Further, the ceramic electronic component according to the present invention,
A structure may be provided in which a plurality of electronic component bodies are provided, and a terminal member is commonly connected to each terminal electrode of the plurality of electronic component bodies.

[0016]

FIG. 1 is a perspective view showing the appearance of a ceramic electronic component 11 according to an embodiment of the present invention. The ceramic electronic component 11 includes, for example, two chip-shaped ceramic electronic component main bodies 12 constituting a multilayer ceramic capacitor and a metal plate.
And two terminal members 13.

FIG. 2 is a perspective view showing one terminal member 13 alone, and FIG. 3 is a plan view showing a metal plate 14 prepared for obtaining the terminal member 13. FIG. 4 is a perspective view showing one electronic component main body 12 shown in FIG. 1 alone. As particularly shown in FIG. 4, the electronic component body 12 has two end faces 15 and 16 facing each other and four side faces 1 connecting the end faces 15 and 16.
7, 18, 19 and 20. On the end surfaces 15 and 16 of the electronic component body 12, the terminal electrodes 2 are formed by hatching so as to indicate the formation regions.
1 is formed. The terminal electrode 21 may be formed by a thin-film forming technique such as sputtering, vapor deposition, or plating, may be formed by a thick-film forming technique of applying and baking a conductive paste, or may be formed by a thick-film forming technique. It may be formed by plating the film.

In this embodiment, the terminal electrode 21 is formed so as to extend not only on the end faces 15 and 16 but also on the side faces 18 and 20 which are adjacent to the end faces 15 and 16 and face each other. 15 and 16
Are formed so as not to extend to the side surfaces 17 and 19 facing each other while being adjacent to the. Terminal electrode 21
May be formed at least on the end faces 15 and 16, for example, may be formed only on the end faces 15 and 16.

As shown in FIG. 1, the two electronic component bodies 12 are vertically stacked while being oriented in the same posture.
For example, they are joined by an adhesive (not shown).
The terminal member 13 is configured by the metal plate 14 as described above. The terminal member 13 is formed by bending one end of the metal plate 14 with respect to the base via a bending line 22 shown by a broken line in FIG.
Is shown with imaginary lines. ) Is formed.

In order to obtain the ceramic electronic component 11 shown in FIG. 1, the terminal member 13 is provided with each terminal electrode at the base such that the connection terminal portion 24 is located facing the lower side surface 19 of the lower electronic component body 12. 21. For this connection, for example, a conductive bonding material such as solder or a conductive adhesive is used. When solder is used as the conductive bonding material, a solder immersion method or a solder reflow method can be employed to attach the terminal member 13. Thus, each terminal electrode 2 of the two electronic component bodies 12
1 is connected to the terminal member 13 in common.

As shown in FIG. 3, an L-shaped notch 25 is provided on each side of the metal plate 14 serving as the terminal member 13. The portion surrounded by these cuts 25 is bent through a bending line 26 shown by a broken line,
A shelf 27 as shown in FIG. 2 is formed. As shown in FIG. 1, these shelf portions 27 are for receiving the side surfaces 19 of the lower electronic component body 12 facing the connection terminals 24, whereby the electronic component body 12 and the terminal member 13 are connected to each other. Positioning is facilitated.

FIGS. 2 and 3 show the regions where the solder non-affinity surfaces 28 and 29 which are not compatible with solder are formed by hatching. The solder non-affinity surface 28 may be formed at least on the surface of the connection terminal portion 24 that faces the side surface 19 of the electronic component body 12. In this embodiment, the solder non-affinity surface 28 extends from the connection portion of the terminal member 13 to the terminal electrode 21. The overhanging portion is formed on the entire or almost entire surface facing inward. Further, it is more preferable that the solder non-affinity surface 29 is also formed on the surface of the shelf portion 27 facing the connection terminal portion 24.

In order to provide the above-mentioned solder non-affinity surfaces 28 and 29, this embodiment employs the following method. That is, the metal plate 14 is made of a metal that provides a surface with poor solderability. For example, a metal such as stainless steel or a nickel-iron alloy is used as the material of the metal plate 14. Then, the solder non-affinity surfaces 28 and 2
9 is given by the surface of the metal plate 14 itself.
On the other hand, the other surface of the metal plate 14 is a solder-affinitive surface that is compatible with solder, and in order to provide this solder-affinitive surface, for example, a solder-affinity layer formed by soldering or plating with solder, silver, gold, tin, etc. It is formed. In a more specific embodiment, the solder affinity layer is provided with the terminal electrode 21 on the terminal member 13.
If the terminal member 13 and the terminal electrode 21 are to be soldered, it is sufficient if the terminal member 13 and the terminal electrode 21 are soldered. Are also formed at the connection portion with the terminal electrode 21 at

The solder non-affinity surfaces 28 and 29 as described above
The following method may be employed instead of the method for providing That is, the metal plate 14 is made of a metal that provides a surface with good solderability. Solder non-affinity surface 28
And 29 are formed by treating the surface of the metal plate 14 so as not to fit into the solder, and the solder affinity surface is provided by the surface of the metal plate 14 itself. More specifically, as the above-described treatment for forming the solder non-affinity surfaces 28 and 29, a chemical treatment such as forming a solder non-affinity layer made of a material containing a resin or the like or oxidizing the surface of the metal plate 14 is performed. There is a method of giving. Even in this case, the surface of the metal plate 14 on which the solder affinity surface is to be formed is, for example, solder-plated or plated with solder, silver, gold, tin, or the like to further improve solderability. May be applied.

The ceramic electronic component 11 configured as described above is mounted on a wiring board 23 as shown in FIG. The solder 30 applied in this mounting is applied to the outer surface side of the connection terminal portion 24 of the terminal member 13 to achieve the mounting. On the other hand, since the solder non-affinity surfaces 28 and 29 are formed on the inner surface side of the terminal member 13, the solder 30 does not go around this portion. Therefore, it is possible to prevent the solder 30 from rising along the inner surface of the terminal member 13 and reaching the electronic component body 12. Therefore, it is possible to prevent the electronic component main body 12 from being damaged by thermal shock due to the contact of the solder 30 with the electronic component main body 12, and the solder 30 directly connects the wiring board 23 and the electronic component main body 12, Therefore, it is possible to prevent the deformation or movement of the terminal member 13 for alleviating the stress applied from the wiring board 23 from being hindered.

The effect as described above is obtained by using the solder non-affinity surface 28.
Can be achieved as long as it is formed on at least the surface of the connection terminal portion 24 facing the side surface 19. However, as in this embodiment, the solder non-affinity surface 28 is connected to the terminal member 13 by the connection portion to the terminal electrode 21. A portion that protrudes from the surface and is formed on the entire surface or almost the entire surface facing inward, a solder non-affinity surface 29 is also formed on a surface of the shelf 27 that faces the connection terminal portion 24, or a terminal electrode If the electronic component 21 is not formed on the side surface 19 of the electronic component body 12 facing the connection terminal portion 24, it is possible to achieve more complete achievement of such an effect.

As described above, the electronic component body 1 of the solder 30
2 can be advantageously prevented, so that the height of the electronic component body 12 on the wiring board 23 can be reduced without any problem. Therefore, the ceramic electronic component 11
And the terminal member 13 can be prevented from being easily deformed even by a force 31 from the side of the electronic component body 12. Wiring board 23 and lower side surface 19 of electronic component body 12 shown in FIG.
Is preferably 1 mm or less, more preferably 0.5 mm or less.

An experimental example conducted to confirm the effects of the present invention will be described below. In this experimental example, a ceramic electronic component 11 as shown in FIG. 1 was manufactured. As shown in FIG. 4, terminal electrodes 21 are formed on opposite end surfaces 15 and 16 and side surfaces 18 and 20, and have a longitudinal dimension of 5.7 mm, a width dimension of 5.0 mm, and a thickness dimension of 2.5 mm. And two ceramic electronic component bodies 12 to be the laminated ceramic capacitors thus prepared. These two electronic component bodies 12 were overlapped and joined via an epoxy adhesive.

On the other hand, a terminal member 13 having a shape as shown in FIG. 2 was prepared from a metal plate 14 having a thickness of 0.1 mm and a width of 5.0 mm. In addition, regarding the terminal member 13, the metal plate 14
As the one using nickel-iron alloy as the main material,
In the embodiment according to the present invention, the surface facing the inside of the terminal member 13 is plated with solder except for the solder non-affinity surface 28, and the surface facing the outside is soldered only to the portion corresponding to the back side of the solder non-affinity surface 28. Plated. On the other hand, in the comparative example,
The surface facing inward was solder-plated on the entire surface, and the surface facing outward was solder-plated only on the back side of the solder non-affinity surface 28 as in the example.

Next, the terminal member 13 is connected to the electronic component body 12.
After connecting each of the ceramic electronic components 11 as a sample to the wiring substrate 2 made of an aluminum substrate,
3 was soldered by a solder reflow method. At this time, for each of the example and the comparative example,
And the side a between the side surface 19 of the electronic component body 12 are 0.1 mm (Example 1 and Comparative Example 1) and 0.2, respectively.
mm (Example 2, Comparative Example 2), 0.3 mm (Example 3,
Four types of samples having a thickness of 0.4 mm (Example 4 and Comparative Example 4) were produced.

Examples 1, 2 and 3 thus obtained
And 4, and each of the samples according to Comparative Examples 1, 2, 3, and 4, were subjected to a thermal shock cycle test and a shear strength test. In the thermal shock cycle test, -25
By applying a thermal shock cycle of 1000 ° C. and 150 ° C. 1000 times, the percentage of the sample whose properties have deteriorated to a predetermined value or more is determined as a defective rate. In the shear strength test, the horizontal direction indicated by an arrow 31 in FIG. The percentage of the samples in which the strength when the force was applied was less than a predetermined value was determined as the defective rate. The results are shown in Table 1 below.

[0032]

[Table 1]

As can be seen from Table 1, in the comparative example, the solder 30 for mounting is arranged along the surface facing the inside of the terminal member 13.
As the distance a becomes shorter, the failure rate in the thermal shock cycle test becomes higher. However, in the embodiment according to the present invention, the solder 30 rises along the surface facing the inside of the terminal member 13. Is prevented, the distance a is reduced to
No defect occurred in the thermal shock cycle test even if the length was reduced to 0.1 mm as in the above. In the shear strength test, no significant difference was observed between the example and the comparative example.

Although the present invention has been described with reference to the specific embodiments, other within the scope of the present invention,
Various modifications are possible. For example, the ceramic electronic component 11 shown in FIG. 1 has two electronic component main bodies 12, but the number of electronic component main bodies can be arbitrarily changed, and even if it is three or more, it is only one. Is also good.

Although the electronic component body 12 constitutes a multilayer ceramic capacitor, the electronic component body 12 may constitute an electronic component body for a ceramic electronic component having other functions. Also, the illustrated electronic component body 12
Has terminal electrodes 21 on at least both end faces 15 and 16.
However, as long as the terminal electrodes are formed on at least both end surfaces, a terminal electrode may be further formed on another portion such as an intermediate portion.

[0036]

As described above, according to the present invention, a chip-shaped ceramic electronic component body having terminal electrodes formed at least on each end face is provided, and the chip-shaped ceramic electronic component body is mounted on a wiring board. In order to alleviate the transmission of stress to the electronic component body based on the expansion and contraction of the wiring board due to temperature changes that cause damage to the electronic component body,
One end of the base is bent with respect to the base to form a connection terminal to the wiring board, and the base is positioned so as to face the side surface of the electronic component body. In such a ceramic electronic component having a terminal member connected to each terminal electrode, at least the surface of the connection terminal portion facing the side surface of the electronic component body has a solder-incompatible surface that does not fit into the solder. Therefore, the solder applied for mounting is prevented from rising so as to reach the electronic component main body, and the solder directly connects the wiring board and the electronic component main body or prevents the above-described stress. To prevent deformation or movement of the terminal member for alleviating the transmission of power. Therefore, the original significance of providing the terminal member is not diminished.

As described above, since the solder for mounting is prevented from undesirably rising along the terminal member, the terminal in the terminal member is not bothered by such rising of the solder. The length of the portion protruding from the connection portion to the electrode can be further reduced. Therefore, the length of the overhanging portion can be reduced to the extent that undesired deformation of the terminal member can be prevented when a lateral force is applied to the electronic component body, and the mounting height of the ceramic electronic component can be reduced. It can be lower and the volume mounting density can be further improved.

In the present invention, the metal plate constituting the terminal member is made of a metal giving a surface having poor solderability,
In order to provide a solder affinity surface which is provided by the surface itself of the metal plate and which at least protrudes from the connection portion to the terminal electrode in the terminal member and which faces outward, the surface having no affinity for solder is provided. When the solder affinity layer is formed, it is easy to form a solder non-affinity surface, and at the time of mounting, good solderability by the solder affinity layer can be secured.

Further, in the present invention, as described above, the solder non-affinity surface is formed on the entire surface or almost the entire inward surface of the terminal member that protrudes from the connection portion to the terminal electrode. The effect of preventing undesired rise of solder is further enhanced. Further, in the present invention, when the terminal member has a shelf-like portion formed by bending a part of the metal plate to receive the side surface facing the connection terminal portion in the electronic component body, Appropriate alignment with the terminal member is facilitated, and such ease of alignment facilitates partial formation of the above-mentioned solder non-affinity surface in a desired region.

In the case where the shelf portion is provided as described above, if the solder non-affinity surface is also formed on the surface of the shelf portion facing the connection terminal portion, undesired solder is not formed along the terminal member. The effect of preventing the rise can be more completely achieved. Further, in the present invention, when the terminal electrode is not formed on the side surface of the electronic component body facing the connection terminal portion, in this case, the effect of preventing the undesired rise of the solder is more perfected. Can be planned.

Further, when the ceramic electronic component according to the present invention includes a plurality of ceramic electronic component bodies, and the terminal members are commonly connected to the respective terminal electrodes of the plurality of electronic component bodies, the terminal members may A function of electrically connecting the electronic component bodies to each other and mechanically fixing them can also be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a ceramic electronic component 11 according to an embodiment of the present invention, and shows a wiring board 2 by imaginary lines.
3 also shows the mounting state.

FIG. 2 is a perspective view showing one terminal member 13 shown in FIG. 1 alone.

3 is a plan view showing a metal plate 14 prepared to obtain the terminal member 13 shown in FIG.

FIG. 4 is a perspective view schematically showing the ceramic electronic component body 12 shown in FIG. 1 alone.

FIG. 5 is a perspective view showing the appearance of a conventional ceramic electronic component 1 which is of interest to the present invention, and also shows a mounting state on a wiring board 5 by imaginary lines.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ceramic electronic component 12 Ceramic electronic component main body 13 Terminal member 14 Metal plate 15, 16 End face 17, 18, 19, 20 Side surface 21 Terminal electrode 22, 26 Folding line 23 Wiring board 24 Connection terminal part 25 Cutout 27 Shelf part 28, 29 Solder non-affinity surface 30 Solder

Claims (7)

[Claims] 1. A chip-shaped ceramic electronic component body having two opposite end faces and a side face connecting the two end faces, and having at least a terminal electrode formed on each of the end faces, and a metal plate. And one end portion thereof is bent with respect to the base portion to form a connection terminal portion to the wiring board, and each of the terminals at the base portion is positioned such that the connection terminal portion is opposed to the side surface. A ceramic electronic component, comprising: a terminal member connected to an electrode; and at least a surface facing the side surface of the connection terminal portion is formed with a solder non-affinity surface that is not compatible with solder. 2. The metal plate is made of a metal that provides a surface with poor solderability, and the solder non-affinity surface is provided by the surface of the metal plate itself, and at least the terminal member is connected to the terminal electrode. 2. The ceramic electronic component according to claim 1, wherein a solder affinity layer is formed on an outwardly facing surface, which is a portion protruding from the portion, so as to provide a solder affinity surface compatible with solder. 3. 3. The solder incompatible surface is a portion of the terminal member that protrudes from a portion connected to the terminal electrode and is formed on the entire surface or substantially the entire surface facing inward. 3. The ceramic electronic component according to 1. 4. The terminal member receives the side surface of the electronic component body facing the connection terminal portion.
The ceramic electronic component according to claim 1, further comprising a shelf portion formed by bending a part of the metal plate. 5. The solder non-affinity surface is also formed on a surface of the shelf portion facing the connection terminal portion.
The ceramic electronic component according to claim 4. 6. The ceramic electronic component according to claim 1, wherein said terminal electrode is not formed on said side surface of said electronic component main body which faces said connection terminal portion. 7. The ceramic according to claim 1, further comprising a plurality of said electronic component main bodies, wherein said terminal member is commonly connected to each of said terminal electrodes of said plurality of electronic component main bodies. Electronic components.