JP4595325B2 - Ceramic electronic components - Google Patents

Description

The present invention relates to a ceramic electronic component, in particular for example multilayer capacitor, a laminated inductor, a ceramic electronic component external electrodes of ceramic electronic components such as laminated thermistor is formed by using a resin curing conductive paste.

  Conventionally, in order to form an external electrode of a ceramic electronic component, a conductive paste obtained by dispersing a conductive metal powder such as silver and an organic binder made of a resin in an organic solvent is used. In particular, conductive pastes are attracting attention as conductive materials that substitute for solders that do not contain harmful substances such as lead, which are becoming increasingly regulated worldwide, as awareness of environmental issues increases. Among them, the resin curable conductive paste that is cured at a low temperature such as 150 ° C. to 200 ° C. as disclosed in Patent Document 1 is higher than the fired conductive paste that requires a high temperature of about 500 ° C. to 800 ° C. The heat damage to other materials is small, less energy is used at the time of curing, leading to energy saving, and the cured product is flexible and excellent in crack resistance (see Patent Document 1).

JP 2002-367427 A

Firing-type conductive paste is a paste mainly containing a conductive component (metal powder such as silver or nickel), an organic binder, and an organic solvent. By applying heat, a resin component (of an organic solvent or an organic binder) is used. Most of them are scattered and the resin does not remain in shape. That is, the fired conductive paste is a paste that retains conductivity when the remaining conductive component is sintered.
On the other hand, resin-curable conductive paste mainly contains a conductive component (metal powder such as silver and nickel) and a thermosetting resin, and by applying heat to this, it cures together with the conductive component without scattering the resin. Thus, since the contact between the conductive components is maintained via the resin, the resin remains as it is without being scattered.
In such a resin curable conductive paste, since the resin as an insulator remains in the cured product after curing, the conductive components such as silver are unlikely to sinter like the fired conductive paste. For this reason, the conductivity of the resin curable conductive paste depends exclusively on the contact of conductive components such as silver, and the problem is that a low resistivity (specific resistance) cannot be obtained as in the case of a baked conductive paste. was there.
Therefore, as a means for reducing the resistivity of the resin curable conductive paste, it is conceivable to increase the amount of silver as a conductive component.
However, when silver is blended in a certain amount or more, there arises a problem that the adhesive strength of the conductive paste to the substrate decreases with a decrease in the content of the thermosetting resin.

Therefore, the main object of the present invention is to provide a resin curable conductive material that can reduce the resistivity and has good adhesion to the substrate regardless of the amount of metal powder such as silver as the conductive component. to provide a ceramic electronic component has an external electrode formed using the sexual paste.

The ceramic electronic component according to the present invention is a ceramic electronic component having a ceramic body and an external electrode, and the external electrode is formed using a resin curable conductive paste, and is cured as a resin curable conductive paste. Resin, a metal powder, and a metal resinate, and the metal resinate is added in a range of 0.3 wt% to 10 wt % with respect to the metal powder, and the metal powder is contained in the cured resin-cured conductive paste. The ceramic electronic component is characterized by being contained in an amount of 55 wt% to 95 wt%.
In the resin curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention, when the metal resinate is added in the range of the amount of the metal powder as described above, the amount of the metal powder in the conductive paste is changed. Even if it does not increase, the resistivity can be lowered. That is, even if the blending amount of the metal powder is constant, if the metal resinate is added, the resistivity can be reduced and the conductivity can be improved.
Although the action of the metal resinate in the resin curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention is not clear, it improves the wettability between the resin and the metal powder, or reduces the volume resistance of the resin. It seems that the resistivity is reduced because of this.
Moreover, if it is said range, the resistivity in a practical level can be made low and adhesiveness can also be maintained. That is, conventionally, in a resin curable conductive paste, when the content of a conductive component such as silver is increased, the content of the resin is decreased, and thus the strength of the cured product and the adhesion to the substrate tend to be decreased. However, if the invention of the present application is used, it is possible to achieve both adhesion and conductivity, and preferable adhesion and conductivity can be obtained at a practical level.
Conventionally, it is known to add a metal resinate to a fired conductive paste. However, this metal resinate acts as a sintering aid.
On the other hand, the present invention has been made by finding that the resistivity can be lowered by adding a metal resinate to a resin curable conductive paste that is not sintered.

In the resin curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention, the metal resinate is preferably a compound containing at least one of silver, copper and nickel.
By adding such a metal resinate, which is a compound containing silver, copper, and nickel, which easily obtains conductivity, the effect of the present invention is particularly remarkable.

According to the present invention, there is provided a ceramic electronic component in which an external electrode is formed using a resin-curing conductive paste capable of reducing the resistivity regardless of the amount of metal powder such as silver as a conductive component. can get.
In addition, according to the present invention, the resistivity of the resin-cured conductive paste that forms the external electrodes of the ceramic electronic component can be greatly reduced without impairing mechanical properties such as adhesion strength.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following description of the best mode for carrying out the invention.

The metal resinate used in the present invention is a compound represented by the following formula (1).
MX-R (1)
In the formula (1), M represents a metal, X represents oxygen, nitrogen or sulfur, and R represents an alkyl group. Among these, a metal resinate containing silver, copper, and nickel has a remarkable effect in reducing the resistivity. As these compounds, for example, silver octylate, silver naphthenate, silver sulfide balsam, silver dihexyl sulfide, copper octylate, copper naphthenate, copper oleate, nickel octylate, nickel naphthenate, nickel oleate, etc. are used. .
Moreover, it is preferable that the addition amount of a metal resinate is used within the range of 0.3 wt%-10 wt% with respect to metal powder. When the addition amount of the metal resinate is less than 0.3 wt%, there is too little metal resinate in the conductive paste, so that the effect is not recognized, or even if it is recognized, it is negligible. On the other hand, when the addition amount of the metal resinate is more than 10 wt%, although the resistivity lowering effect is recognized, the mechanical properties such as the adhesiveness of the paste cured product are remarkably impaired. Have difficulty.

  The thermosetting resin used in the present invention may be any one as long as it is cured by heating. For example, epoxy resin, urethane resin, vinyl ester resin, silicone resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, polyimide resin and the like are used.

Moreover, as a metal powder used by this invention, although arbitrary metal materials, such as silver, palladium, copper, nickel, gold | metal | money, platinum, aluminum, zinc, and tin, can be used, electroconductivity, cost In view of reliability, silver is optimal. Here, the blending amount of the metal powder is preferably 55 wt % or more and 95 wt % or less in the cured conductive paste, and can be arbitrarily determined, but it is 55 wt % or more and 93 wt % or less in the cured conductive paste. More preferably. If the content of the metal powder such as silver in the cured conductive paste is less than 55 wt%, the metal powder such as silver is hardly contacted even after curing, and a practical level of conductivity may not be expected. On the other hand, when the content of the metal powder such as silver in the cured product is more than 95 wt%, the cohesive strength of the resin is decreased and the resistivity is increased, and the mechanical properties such as strength and adhesion of the paste cured product are increased. descend.

Furthermore, in addition to these materials, the resin-curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention imparts special functions to the conductive paste such as thixotropic properties and adhesion. Any organic or inorganic material may be mixed for the purpose. Furthermore, any organic solvent can be used for adhesion adjustment and the like.

The resin curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention can be used as an external electrode of a semiconductor electronic component such as a multilayer capacitor, a multilayer inductor, or a multilayer thermistor.

Hereinafter, the present invention will be described in detail using examples.
In the examples, “isocyanate” is an IPDI block type isocyanate, “polyol” is a polyether polyol, “silver powder” is flaky silver powder with D ₅₀ = 4 μm, and “organic solvent” is alcohol. It is a system solvent. Further, the following resinates were used as “metal resinates”.
Resin A: Silver-based resinate Resinate B: Copper-based resinate Resinate C: Nickel-based resinate Also, it was confirmed by DSC measurement that these metal resinates do not decompose at the curing temperature of this example. It was regarded as a resin component.
In addition, the metal resinate basically has no functional group that reacts with the resin component, and as described above, no decomposition reaction occurs at the curing temperature. Therefore, it seems that it is taken into the gap between the molecular chains of the cured resin as it is or adsorbed on the surface of the silver powder.

[Preparation of conductive paste]
The raw materials having the compositions shown in Tables 1 to 3 were prepared in a planetary mixer and mixed for 60 minutes. Furthermore, the silver powder was uniformly dispersed by passing once through three rolls to prepare a conductive paste.

[Preparation of test piece for resistivity measurement]
The produced conductive paste was printed on a slide glass using a 200-mesh stainless steel printing pattern. Next, the printed conductive paste was put into an oven, heated at 200 ° C. for 1 hour, and cured to obtain a cured product.

[Resistivity measurement]
The resistance value of the cured product was measured with a resistance measuring instrument. Next, the cross-sectional area of the cured product was measured with a film thickness meter, and the cross-sectional area was calculated from the obtained chart using an image processing apparatus. Furthermore, from the resistance value and the cross-sectional area value of the cured product, the resistivity σ (Ω · cm) of each conductive paste was calculated by the equation (2), and the resistivity was converted to μΩ · cm.
σ = R × (A / D) (2)
Here, R represents resistance (Ω), A represents cross-sectional area (cm ² ), and D represents distance between electrodes (cm).

[Production of test piece for cross-cut tape test]
The conductive paste was uniformly applied in a range of 20 mm × 20 mm with a thickness of about 50 μm on the steel plate. Next, the applied conductive paste was put into an oven and cured by heating at 200 ° C. for 1 hour to obtain a cured product.

[Crosscut tape test]
A cutter guide (gap spacing 2 mm, square 25) was placed on the cured product, and a grid-like cut was made using a cutter knife. Next, a cellophane adhesive tape was affixed on the cut and rubbed with an eraser to make it adhere, and then the tape was peeled off instantaneously. The test results are visually observed. The peeled surface area of the cured product is 0 to 10% as “◯”, 10 to 30% as “△”, and when the peeled area is larger than 30%, it is practically difficult to use. Since it was considered, it was set as “x”.

[Evaluation results]

  As is apparent from Table 1, Samples 1 to 4 in which the silver content is 90 wt%, the compounding amounts of isocyanate and polyol as the resin components are the same, and the metal resinate is added, the metal resinate is added. It can be seen that the resistivity is lower than that of the sample 5 that is not. That is, even if the resin-cured conductive paste has a high metal powder content, the resistivity can be lowered by adding a metal resinate.

Similarly, as is clear from Table 2, sample 7 and sample 8, sample 9 and sample 10, sample 11 and sample 12, sample 13 and sample 14, sample 15 and sample 16 are combined. Even if it compares each, it turned out that the Example which added the metal resinate can make a resistivity low compared with the comparative example which does not add a metal resinate.
However, the practical resistivity is less than 5 digits, and the resistivity of Sample 6 is high, and it was found that sufficient conductivity could not be obtained when actually used as a resin-cured conductive paste.
Moreover, about the sample 17, the adhesive force of resin fell with the fall of thermosetting resin content, and desired adhesive strength was not able to be obtained.

Further, as apparent from Table 3, the samples 19 to 24, 26 and 27 in which the blending amount of the metal powder is 55 wt% to 95 wt% and the addition amount of the metal resinate is 0.3 wt% to 10 wt% are shown. Also, it was found that adhesion in a cross cut tape test was sufficiently obtained, and a resistivity of 3000 (μm · cm) or less, which is suitable as an electrode of an electronic component, was sufficiently obtained.
On the other hand, it was found that the sample 25 in which the addition amount of the metal resinate is 15 wt% can have a lower resistivity than the case where the metal resinate is not added, but the adhesion cannot be obtained.
Further, it was found that the sample 28 containing more than 95 wt% of metal powder is still in a range where a low resistivity can be obtained, but the resin content is too small and sufficient adhesion cannot be obtained.
Furthermore, it was found that Sample 18 having less than 55 wt% metal powder has a metal powder content that is too small to obtain a sufficiently low resistivity.

The resin curable conductive paste used for the external electrode of the ceramic electronic component according to the present invention can be applied to an application of the external electrode of the ceramic electronic component such as a multilayer capacitor.

Claims (2)

A ceramic electronic component having a ceramic body and external electrodes,
The external electrode is formed using a resin curable conductive paste,
As the resin curable conductive paste,
Containing a thermosetting resin, a metal powder, and a metal resinate;
The metal resinate is added in a range of 0.3 wt% to 10 wt % with respect to the metal powder,
The metal powder is contained in a cured resin curable conductive paste in an amount of 55 wt% to 95 wt%. The ceramic electronic component according to claim 1, wherein the metal resinate is a compound including at least one of silver, copper, and nickel.