JP2002164246A - Electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the junction state can not be held by the molten non-lead solder in a solder reflow process in soldering a terminal plate to a wiring substrate, when non-lead solder is used taking environmental problems into consideration, in a structure for jointing a terminal plate consisting of a metal plate to a terminal electrode on an electronic component body. SOLUTION: A terminal electrode 3 and a terminal plate 5 are jointed by using both a resin junction 8 formed of electrically insulating resin, and a solder 9. Preferably, the resin junction material 8 is applied to the side of a free end part 7 of the terminal plate 5 from the solder 9, so that the solder 9, if molten, is prevented from running down by the resin junction material 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component having a structure in which a terminal plate member is joined to a terminal electrode, and more particularly to an improvement in a joint structure between a terminal electrode and a terminal plate member.

[0002]

2. Description of the Related Art In an electronic component such as a multilayer ceramic capacitor, for example, a state in which a base of a conductive terminal plate member made of a metal plate is joined to a terminal electrode formed on the outer surface of the electronic component body. May be done. When mounting an electronic component having such a terminal plate member on a wiring board, the free end of the terminal plate member is soldered to the wiring board.

This is intended to improve the thermal shock resistance. That is, when mounting the electronic component on the wiring board, if the terminal electrodes formed on the electronic component main body are directly soldered to the wiring board, the electronic component main body and the wiring may be connected in an environment where a temperature change is caused. This is intended to prevent the occurrence of mechanical damage such as the destruction of the electronic component body due to the difference in thermal expansion coefficient between the terminal plate member and the substrate due to the difference in the coefficient of thermal expansion.

[0004] The above-mentioned problems are particularly likely to occur when the electronic component body is made of ceramic or when the wiring board is made of aluminum having excellent heat dissipation.

[0005] In the manufacture of an electronic component having the above-mentioned terminal plate member, for example, solder is used to join the terminal plate member to the terminal electrode.

[0006]

However, when the terminal electrodes and the terminal plate members are joined by soldering, the following problems to be solved may be encountered.

That is, the solder for joining the terminal electrode and the terminal plate member needs to withstand a later-described soldering onto the wiring board via the terminal plate member, for example, a reflow soldering process. Therefore, under a temperature condition corresponding to the melting point of the solder used for soldering on the wiring board, it is necessary to use a high-temperature solder having a high melting point capable of maintaining the bonding state.

On the other hand, regarding the material of the solder, the use of lead-based solder is being restricted due to environmental problems.
For example, lead-free solders such as Sn-Ag solders have been used.

As the lead-free solder, Sn-Ag based (eutectic point 221 ° C.), Sn—Ag—Bi based (melting point 183-21)
2 ° C.), Sn—Zn-based (melting point: 186 to 188 ° C.), etc., all of which are existing 60% Sn-40.
The melting temperature is higher than the eutectic point of 183 ° C. of the% Pb solder. Therefore, when these lead-free solders are used for soldering a terminal plate member onto a wiring board, the solder used for joining the terminal electrode and the terminal plate member is, for example, 23.
Although it must be able to maintain the bonding state at a high temperature of 0 ° C. or higher, a lead-free solder capable of maintaining the bonding state at such a high temperature has not yet been realized.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned disadvantages of the solder used for joining a terminal electrode and a terminal plate member in an electronic component having the terminal plate member.

[0011]

SUMMARY OF THE INVENTION In brief, the present invention intends to use resin together with solder for joining a terminal electrode and a terminal plate member.

That is, the present invention provides an electronic component body having a terminal electrode formed on an outer surface thereof, and a conductive terminal plate member joined at the base portion so as to be electrically connected to the terminal electrode. In order to solve the above-mentioned technical problems, the terminal electrode and the terminal plate member are provided with both a resin joining material made of an electrically insulating resin and a solder joining material made of solder. It is characterized by being joined by.

In a preferred embodiment of the present invention, the terminal plate member is electrically connected to the wiring board at a free end opposite to the base.

[0014] Preferably, the resin bonding material is provided on the free end side of the terminal plate member with respect to the solder bonding material, or is provided so as to surround the solder bonding material.

The base of the terminal plate member may be provided with a through hole for introducing a solder paste for providing a solder bonding material to a portion where the base and the terminal electrode face each other. A through hole for introducing a resin paste for giving a material may be provided.

The present invention is particularly advantageously applied when the solder constituting the solder bonding material is a lead-free solder.

[0017]

FIG. 1 is a front view showing the entire appearance of an electronic component 1 according to an embodiment of the present invention.

The electronic component 1 includes, for example, three chip-shaped electronic component bodies 2 constituting a multilayer ceramic capacitor. Terminal electrodes 3 are formed on the outer surface of the electronic component main body 2, more specifically, on two end faces opposed to each other.

The terminal electrode 3 is formed by, for example, a thick film forming technique such as applying and baking a conductive paste. Here, as the conductive paste, for example, a paste containing copper, silver, platinum or gold as a conductive component is used.

Further, in order to improve the wettability with respect to the solder to be described later, if necessary, for example, dry barrel polishing or sand blasting containing alumina powder is applied to the surface of the baked terminal electrode 3. Removal of glass components is performed.

If necessary, the surface of the terminal electrode 3 formed by the thick film forming technique is plated with, for example, nickel, and further plated with copper, silver or gold, for example. Thereby, good solder wettability is provided.

Note that the terminal electrode 3 may be formed by a thin film forming technique such as sputtering, vapor deposition, and plating.

The three electronic component bodies 2 are stacked one above the other while being oriented in the same posture, and are joined to each other by, for example, an adhesive 4.

Each terminal electrode 3 of the three electronic component bodies 2
A conductive terminal plate member 5 is joined at its base 6 so as to be electrically connected in common. Terminal plate member 5
In this embodiment, is formed by a metal plate bent in an inverted U-shape as a whole, and is electrically connected at its free end 7 to a wiring board (not shown).

The metal plate constituting the terminal plate member 5 is provided with conductivity by using a metal such as silver, gold, nickel, copper or iron, or an alloy thereof, for example. You may. Terminal plate member 5
Is made of a clad material, the inside of the terminal plate member 5 bent in an inverted U-shape is made of a material having poor solder wettability such as, for example, an Fe-Cr alloy, a Ni-Cu alloy, or Al. On the other hand, the outside is made of a material having good solder wettability, such as copper.

With the above configuration, the terminal plate member 5 gives good solder wettability to the surfaces facing the terminal electrode 3 and the wiring board, respectively, in a state where the terminal plate member 5 is bent in an inverted U-shape. On the other hand, the surface facing inward can be a surface having poor solder wettability. Accordingly, the terminal plate member 5 enables good soldering between the terminal electrode 3 and each of the wiring boards, and prevents undesired wrapping of the solder into the inside of the inverted U-shaped bent portion. Thus, the deformation of the terminal plate member 5 for preventing the electronic component main body 2 from being broken due to the temperature change described above can be prevented from being undesirably hindered.

As described above, instead of forming the terminal plate member 5 from a clad material, a surface treatment such as plating may be employed so as to exert the same function.

The base 6 of the terminal plate member 5 and the terminal electrode 3 on the electronic component body 2 are joined by both a resin joining material 8 made of resin and a solder joining material 9 made of solder. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and shows a joint portion between one electronic component main body 2 and the terminal plate member 5. In this embodiment, the resin bonding material 8 is
It is provided on the free end 7 side of the terminal plate member 5 from the solder bonding material 9.

The above-mentioned resin bonding material 8 functions as an adhesive, and is, for example, epoxy-based, polyimide-based,
Silicone-based or paraffin-based resins can be used. In this case, as the resin bonding material 8, conductive powder is used because it is difficult to swell, has good moisture resistance, has high adhesive strength, has high stability and reliability of the adhesive strength, and has a relatively low cost. An electrically insulating resin not containing is used.

On the other hand, as the solder bonding material 9, it is preferable to use a lead-free solder such as a solder containing tin as a main component in consideration of environmental problems. As such a tin-containing lead-free solder, specifically, Sn-Cu based, Sn-S
b-based, Sn-Ag-based, Sn-Ag-Bi-based, Sn-Zn
And more specifically, Sn-2% Cu solder,
There are Sn-5% Sb solder, Sn-3.5% Ag solder and the like.

In order to achieve the bonding between the terminal electrode 3 and the terminal plate member 5 by the resin bonding material 8 and the solder bonding material 9, a resin paste is applied to approximately one third of the lower side of the terminal electrode 3. , A solder paste is applied to approximately one third of the upper part.

Next, with the terminal electrode 3 and the base 6 of the terminal plate member 5 facing each other, a heat treatment is performed at a temperature at which the resin paste can be cured but the solder paste cannot be melted to give the resin bonding material 8. Thus, the resin paste is cured. Thereby, a state where the terminal electrode 3 and the terminal plate member 5 are mechanically joined is obtained.

Further, the electronic component body 2 holding the terminal plate member 5 via the resin bonding material 8 is put into a reflow furnace, whereby the solder paste to be the solder bonding material 9 is melted. When the terminal electrode 3 and the terminal plate member 5 are taken out of the reflow furnace, the terminal electrode 3 and the terminal plate member 5 are electrically and mechanically joined by the solder joining material 9 provided by the solder paste.

In the resin paste curing step described above, the three electronic component bodies 2 are positioned in a vertically stacked state without using the adhesive 4 for joining the electronic component bodies 2 to each other, and are cured. The positional relationship between the three electronic component bodies 2 may be fixed by the resin bonding material 8.

According to this embodiment, the resin bonding material 8 is
Since it is located on the free end portion 7 side of the terminal plate member 5 with respect to the solder bonding material 9, even if the solder paste is melted in the above-described reflow process, the free end portion 7 of the terminal plate member 5 is connected to the wiring board Even if the solder bonding material 9 is melted in a subsequent reflow process for soldering, the flow of such solder can be advantageously prevented by the resin bonding material 8.

FIG. 3 is a diagram corresponding to FIG. 2 for explaining another embodiment of the present invention. In FIG. 3, FIG.
The elements corresponding to the elements shown in are denoted by the same reference numerals,
Duplicate description will be omitted.

In the embodiment shown in FIG. 3, the resin bonding material 8
After applying a resin paste for giving
The resin paste is cured so that the resin bonding material 8 is applied in a state where the terminal plate member 5 and the base 6 (see FIG. 1) of the terminal plate member 5 are opposed to each other. To join. Next, the electronic component body 2 holding the terminal plate member 5 is immersed in a solder bath, whereby the solder bonding material 9 is formed between the terminal electrode 3 and the base 6 of the terminal plate member 5.

FIGS. 4A and 4B are diagrams for explaining still another embodiment of the present invention. FIG. 4A is a side view of the terminal plate member 11, and FIG. FIG. 3 is a cross-sectional view along B, and also shows the electronic component body 2 with imaginary lines. 4, elements corresponding to the elements shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Referring to FIG. 4, terminal plate member 11 has an L-shaped cross section as a whole, and
It has a base 12 joined electrically to the upper terminal electrode 3 and a free end 13 electrically connected to a wiring board (not shown).

As a characteristic configuration of this embodiment, a solder bonding material 9 (see FIGS. 1 to 3) is provided on the base 12 of the terminal plate member 11 at a portion where the base 12 and the terminal electrode 3 face each other. A solder paste introduction through hole 14 for introducing a solder paste to be provided is provided, and a resin paste introduction through hole 15 for introducing a resin paste for providing a resin bonding material 8 (see FIGS. 1 to 3) is provided. Have been.

In such an embodiment, the terminal electrode 3
In order to obtain a state in which the base portion 12 of the terminal plate member 11 is joined to the resin plate, the resin paste is dispensed from the resin paste introduction through hole 15 by using a dispenser with the three electronic component bodies 2 and the terminal plate member 11 positioned. Injected. Next, the resin paste is cured, so that the terminal plate member 11 is mechanically joined to the terminal electrode 3.
The resin bonding material 8 (see FIGS. 1 to 3) is
And the terminal electrode 3.

Next, the solder paste is injected from the through-hole 14 for introducing solder paste using a dispenser.
Thereafter, the solder paste is melted by a reflow furnace, whereby a solder bonding material 9 (see FIGS. 1 to 3) is formed between the terminal plate member 11 and the terminal electrode 3, and the terminal plate member 11 and the terminal electrode 3 is electrically and mechanically joined.

Looking at the positional relationship between the solder paste introducing through-hole 14 and the resin paste introducing through-hole 15 described above, the solder paste introducing through-hole 14 for one terminal electrode 3 is the resin paste introducing through-hole 15. Is located above. Therefore, according to this embodiment, FIG.
As shown in (1), the resin bonding material 8 can be applied to the free end 13 of the terminal plate member 11 from the solder bonding material 9.

FIG. 5 is a diagram corresponding to FIG. 2 for explaining still another embodiment of the present invention. In FIG. 5, elements corresponding to the elements shown in FIG. 2 or FIG. 4 are denoted by the same reference numerals, and redundant description will be omitted.

Referring to FIG. 5, on terminal electrode 3,
The resin bonding material 8 is provided so as to surround the solder bonding material 9. Also according to such an application mode, the resin bonding material 8 can prevent the solder bonding material 9 from melting and flowing down.

In order to obtain the application mode as shown in FIG. 5, for example, the solder paste introduction through-hole 14 and the resin paste introduction hole are provided at positions indicated by broken lines in the base 12 of the terminal plate member 11 (see FIG. 4). The through-hole 15 may be provided.

In each of the embodiments shown in FIGS. 4 and 5, one of the solder paste introducing through-hole 14 and the resin paste introducing through-hole 15 may be omitted. In this case, the resin paste or the solder paste is applied on the base 12 or the terminal electrode 3 before the base 12 of the terminal plate member 11 faces the terminal electrode 3.

As described above, the present invention has been described in relation to the illustrated embodiment. However, within the scope of the present invention,
Various modifications are possible.

For example, the application mode of the resin bonding material 8 and the solder bonding material 9 is not limited to the mode shown in FIG. 2, FIG. 3 or FIG. 5, but may be changed to another mode.

Although the illustrated electronic component 1 has three electronic component main bodies 2, the number of electronic component main bodies can be changed arbitrarily. May also be four or more.

The electronic component body 2 constitutes a multilayer ceramic capacitor, but constitutes a ceramic electronic component having other functions or an electronic component body for an electronic component containing no ceramic. There may be.

In the illustrated electronic component body 2, the terminal electrodes 3 are formed on two opposite end surfaces. However, the terminal electrodes are formed on other outer surface portions such as an intermediate portion. It may be something.

[0053]

As described above, according to the present invention, when a terminal electrode on an electronic component body is joined to a terminal plate member electrically connected to the terminal electrode, a combination of a resin joining material and a solder joining material is used. Is used, the strength shortage due to melting or semi-melting of the solder bonding material at a high temperature can be compensated for by bonding with the resin bonding material. Therefore, the bonding state between the terminal electrode on the electronic component body and the terminal plate member electrically connected thereto can sufficiently withstand the heat applied when the terminal plate member is soldered onto the wiring board. Can be realized between.

Further, since an electrically insulating resin is used as the resin constituting the above-mentioned resin bonding material, the resin is less likely to swell and has better moisture resistance than a case where a conductive resin containing a conductive powder is used. Therefore, the bonding strength can be increased, the bonding stability and reliability can be ensured, and the cost can be reduced.

In the present invention, if the resin joining material is applied to the free end side of the terminal plate member with respect to the solder joining material or is applied so as to surround the solder joining material, the solder joining material melts. Even so, the flow-down can be advantageously prevented by the resin bonding material.

Further, if a through hole for introducing solder paste or a through hole for introducing resin paste is provided at the base of the terminal plate member, the electronic component main body is not provided. With the terminal board member positioned,
Since a solder paste to be a solder bonding material for joining and a resin paste to be a resin bonding material can be introduced, the application of the solder paste and the resin paste can be performed with good workability.

When a lead-free solder is used as the solder bonding material, it is possible to prevent lead from causing environmental problems. In addition, in the case of lead-free solder, since the selection range of materials is limited, the melting point of the solder bonding material for bonding the terminal electrode and the terminal plate member is determined by the method for soldering the terminal plate member onto the wiring board. Since it is often difficult to make the melting point sufficiently higher than the melting point of the solder, a configuration in which a resin bonding material is used together with a solder bonding material as in the present invention is particularly effective when such a lead-free solder is used. .

[Brief description of the drawings]

FIG. 1 is a front view showing an electronic component 1 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1 and shows a joint portion between a terminal electrode 3 on one electronic component body 2 and a base 6 of a terminal plate member 5.

FIG. 3 is a view corresponding to FIG. 2 showing another embodiment of the present invention.

4A and 4B are diagrams for explaining still another embodiment of the present invention, wherein FIG. 4A is a side view of a terminal plate member 11, FIG.
(B) is a cross-sectional view along the line BB of (a), and also shows the electronic component body 2 by imaginary lines.

FIG. 5 is a view corresponding to FIG. 2, showing still another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electronic component 2 electronic component main body 3 terminal electrode 5, 11 terminal plate member 6, 12 base 7, 13 free end 8 resin bonding material 9 solder bonding material 14 through hole for introducing solder paste 15 through hole for introducing resin paste

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E082 AA01 AB03 BC23 BC33 CC03 CC07 CC13 GG08 GG11 GG23 JJ09 JJ15 JJ26 JJ27 LL13 MM28 5E319 BB01 BB05 CC33 CD15 CD25 GG03

Claims (7)

[Claims] An electronic component body having a terminal electrode formed on an outer surface thereof; and a conductive terminal plate member joined at a base portion so as to be electrically connected to the terminal electrode; An electronic component, wherein a terminal electrode and the terminal plate member are joined by both a resin joining material made of an electrically insulating resin and a solder joining material made of solder. 2. The electronic component according to claim 1, wherein the terminal plate member is electrically connected to a wiring board at a free end opposite to the base. 3. The electronic component according to claim 1, wherein the resin bonding material is provided on a free end side of the terminal plate member opposite to the base with respect to the solder bonding material. 4. The electronic component according to claim 1, wherein the resin bonding material is provided so as to surround the solder bonding material. 5. A through hole for introducing a solder paste for providing the solder bonding material to a portion where the base and the terminal electrode face each other, wherein the base of the terminal plate member is provided. The electronic component according to claim 1. 6. A through hole for introducing a resin paste for providing the resin bonding material to a portion where the base and the terminal electrode face each other in the base of the terminal plate member. The electronic component according to claim 1. 7. The electronic component according to claim 1, wherein the solder constituting the solder bonding material is a lead-free solder.