JP3064668B2 - Manufacturing method of multilayer ceramic porcelain element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an abnormal high voltage such as noise, pulse and static electricity generated in an electronic device or an electric device.
The present invention relates to a method for manufacturing a multilayer ceramic porcelain element for protecting semiconductor elements such as C and LSI, and circuits of electronic equipment and electric equipment.

[0002]

2. Description of the Related Art In recent years, semiconductor devices such as ICs and LSIs have been widely used for realizing miniaturization and multifunction of electronic devices and electric devices. Susceptible to abnormal high voltages.

Therefore, film capacitors, electrolytic capacitors, semiconductor ceramic capacitors, multilayer ceramic capacitors, and the like are used to suppress abnormal high voltages such as noise, pulses, and static electricity of these electronic devices and electric devices. Although it exhibits excellent characteristics in absorbing and suppressing relatively low voltage noise and high frequency noise, it does not exhibit the effect on high voltage pulses or static electricity, and may cause malfunction or destruction of semiconductor elements.

On the other hand, SiC and ZnO-based varistors are used to absorb and suppress high-voltage pulses and static electricity, but these are effective in absorbing and suppressing relatively low-voltage noise and high-frequency noise. Otherwise, a malfunction of the semiconductor element may be caused.

[0005] Japanese Patent Application Laid-Open No. 57-27001 and Japanese Patent Application Laid-Open No. 57-35303 disclose these two disadvantages.
As shown in the publication, SrTiO ₃ -based varistors have been put to practical use and used.

[0006] On the other hand, in the field of electronic components, lighter, thinner and smaller, and higher performance have been increasingly developed in response to miniaturization of equipment.
The development of chip components that can be surface-mounted has become indispensable. In response to these, examples in which the contents disclosed in JP-A-54-53248 and JP-A-54-53250 are applied, and JP-A-59-215701,
Although there are examples disclosed in Japanese Patent Application Laid-Open No. 63-219115, these methods are still in practical use due to the complicated process and the obtained characteristics are insufficient to achieve the purpose. Stage has not been reached. Therefore, the inventors of the present invention have shown in Japanese Patent Application No. 1-86243 a method which can be put to practical use by a new manufacturing method .

[0007]

Conventionally, a laminated SrTi
Various material compositions and manufacturing methods have been developed for O ₃ varistors as described in the above-mentioned conventional examples, but in any case, the process is complicated or the obtained characteristics are insufficient to achieve the purpose. However, it has not yet reached the stage of practical use. Further, the new method disclosed by the present inventors has a problem that the characteristics become unstable after plating.

[0008] The present invention is intended to solve the conventional problems, and practically possible, and relatively easy multilayer ceramic capable of obtaining a laminated ceramic porcelain element manufacturing method
It is an object of the present invention to provide a method for manufacturing a porcelain element .

[0009]

In order to solve this problem, according to the present invention, a plurality of internal electrode layers, one of which extends to an edge, are alternately arranged via a ceramic layer.
Laminated, and after plating the external electrode portion of the laminated ceramic porcelain element provided with external electrodes at both ends of the internal electrode, left in an aqueous solution having high activity under reduced pressure and atmospheric pressure, Further, the production method is to leave it in ion-exchanged water.

[0010]

According to this manufacturing method, cations or anions adhering to and invading the outside and inside of the laminated ceramic porcelain element are eliminated to the outside of the laminated ceramic porcelain element portion, and residual ions deteriorate characteristics in reliability tests and the like. Can be suppressed.

[0011]

Embodiment (Embodiment 1) The embodiment will be specifically described below.

First, SrTiO ₃ , CaCO ₃ , BaC
O ₃ , MgCO ₃ , and TiO ₂ are weighed at various composition ratios as shown in Tables 1 and ₂ below from 1 to 7 and mixed for 20 hours by a ball mill or the like. Next, after drying, it is fired at 1100 ° C. for 4 hours, crushed again by a ball mill or the like for 75 hours, and dried to obtain a first component.

[0013]

[Table 1]

[0014]

[Table 2]

Next, the first component, the second component, and the third component are weighed so as to have the composition ratios 1 to 7 in (Table 1) and (Table 2), and mixed for 20 hours using a ball mill or the like. And then dried, mixed with a butyral-based resin and an organic solvent such as butyl acetate, and dried by a doctor blade method or the like.
The sheet was formed into a thickness of 0 μm, dried, and cut into a predetermined size.

Then, as shown in FIG. 2, the internal electrode 2 is not formed on the uppermost layer and the lowermost layer of the ceramic sheet 1 cut to a predetermined size, and the Ag-Pd An internal electrode 2 is formed by screen printing or the like so that one end reaches the edge,
These are laminated, for example, 30 layers so that the internal electrodes 2 facing each other alternately reach the edge, pressed, pressed, and cut into a predetermined size. Next, after degreasing at 600 ° C. in air and calcining at 1200 ° C. in air, for example, N ₂ : H ₂ = 1
After calcination at 1250 ° C. for 4 hours in a reducing atmosphere of 0: 1, reoxidation is performed at 900 ° C. for 2 hours in air. Thereafter, an external electrode paste made of Ag or the like was applied to both end surfaces exposing the internal electrode 2 and baked in air at 850 ° C. for 10 minutes to obtain a laminated ceramic ceramic element. Next, for example, Ni plating is performed by an electrolytic method, and further, solder plating is performed. The multilayer ceramic porcelain element thus obtained is shown in a partially cutaway perspective view in FIG.

The laminated ceramic porcelain element is left in an aqueous solution having a high activity, that is, an aqueous solution having a surface tension smaller than that of pure water, for example, an alkylbenzene sulfonic acid, and then immersed in ion-exchanged water.
After standing for 120 minutes and drying at 120 ° C. for 3 hours, the properties of the multilayer ceramic porcelain element thus obtained and the results of the wet and medium load test are shown in Tables 3 and 4 as sample numbers 1 to 7.

[0018]

[Table 3]

[0019]

[Table 4]

Embodiment 2 First, SrTiO ₃ , CaCO ₃ , BaCO ₃ , MgCO ₃ ,
TiO ₂ was replaced with sample number 8 in Tables 1 and ₂ above.
As shown in Tables 1 to 16, the composition ratio is variously changed and weighed, and mixed by a ball mill or the like for 20 hours. Next, after drying 11
Firing at 00 ° C for 4 hours, 75 hours again with a ball mill etc.
After pulverization, it is dried and used as the first component.

Next, the first component, the second component, and the third component are weighed so as to have the composition ratios shown in Sample Nos. 8 to 16 in (Table 1) and (Table 2) described above, and are weighed by a ball mill or the like. 20
After mixing with Hr, the mixture was dried, mixed with a butyral resin and an organic solvent such as butyl acetate, formed into a sheet having a thickness of 50 μm by a doctor blade method, dried, and cut into a predetermined size.

Then, as shown in FIG. 2, the internal electrodes 2 are not formed on the uppermost layer and the lowermost layer of the ceramic sheet 1 cut to a predetermined size, and Ni-Pd Are formed by screen printing or the like so that one of them reaches the edge, for example, 30 layers are laminated such that the opposing internal electrodes 2 alternately reach the edge, and pressure and pressure are applied. Cut to size. Next, after degreased at 700 ° C. in air and further calcined at 1150 ° C. in air, an external electrode paste made of Ni or the like is applied to both end surfaces exposing the internal electrodes 2,
For example, 1270 in a reducing atmosphere of N ₂ : H ₂ = 10: 1
After calcination at 3 ° C. for 3 hours, it is reoxidized in air at 900 ° C. for 2 hours. Then, Ag was applied to both end surfaces exposing the internal electrodes 2.
Apply an external electrode paste consisting of
It was baked at 0 ° C. for 10 minutes to obtain a laminated ceramic porcelain element.
The laminated ceramic porcelain element thus obtained is shown in FIG.
Is shown in a partially cutaway perspective view. Next, an acid-resistant coating material made of, for example, SiO ₂ that resists acidity of pH = 4 is applied by, for example, a dip method, and baked at 400 ° C. for 30 minutes.

The laminated ceramic porcelain element is 25 mmHg
Immersed in an aqueous solution of a surfactant, for example, alkylbenzene sulfonic acid, for 50 minutes, then immersed in ion-exchanged water, dried at 120 ° C. for 3 hours, and then subjected to, for example, Ni plating by an electrolytic method and further solder plating Is applied. The characteristics of the multilayer ceramic porcelain element thus obtained and the results of the humidity and medium load test are shown in Tables 3 and 4 in Sample Nos. 8 to 16.

The conductivity of ion-exchanged water used in standing in water shown in this example was 0.5 μS / cm,
It was confirmed that the same effect was obtained when the value was not more than 00 μS / cm. Further, in this example, the case of standing in water under the atmospheric pressure was not shown, but it was confirmed that the same effect can be obtained by extending the standing time in water under the atmospheric pressure. Furthermore, the degree of decompression when left in decompressed water is particularly limited because the effect of decompression is longer as the pressure is closer to atmospheric pressure, and the effect is only obtained in a shorter time as the pressure is reduced. do not have to.

Further, as for the coating agent used before standing in water, only the coating material made of, for example, SiO _{2 having} acid resistance to withstand the acidity of pH = 4 is shown, but the acid resistance enough to withstand the pH of the plating solution is shown. Any coating agent may be used as long as it has heat resistance, alkali resistance, and heat resistance enough to withstand the temperature during soldering. V _{0.1 mA} is a voltage applied to both ends of the laminated ceramic porcelain element when a direct current of 0.1 mA flows. Further, the shape of the multilayer ceramic porcelain element shown in this embodiment is a size usually called a type 1 or 3.

Although only some of the types of plating are shown, any type of metal may be used.
Electrolytic plating or electroless plating may be used. Although only a part of the aqueous solution with high activity is shown, what kind of aqueous solution has the effect of lowering the free energy at the interface and has a lower surface tension than pure water and can be easily removed by subsequent washing. It can be anything.

[0027]

As described above, according to the present invention, after plating, it is allowed to stand in an aqueous solution having a high activity at atmospheric pressure and then in ion-exchanged water. By eliminating cations and anions that have entered the inside of the device outside the device, the ion concentration in the free state can be reduced. Moreover, by further of the same element in vacuo and allowed to stand at a high activity i.e. less aqueous solution than the surface tension of pure water, further it was left with deionized water, forcibly including immersion water within the same device It is particularly effective for lowering the ion concentration in a free state even in a portion distant from the inner surface of the element.

As a result of the wet and medium load test of the multilayer ceramic porcelain element thus obtained, it was found that after plating, the laminated ceramic porcelain element was left in an aqueous solution having high activity under atmospheric pressure or reduced pressure, and then left in ion-exchanged water. The initial characteristics, especially ta
nδ can be reduced, and the rate of change in varistor voltage and capacitance can be significantly reduced. Also, even when a small amount of ions enter the device through the coating film, the cations and anions that have entered the inside of the device can be excluded to the outside of the device,
It is possible to suppress the ion from deteriorating the characteristics in a reliability test, particularly in a wet load test.

As described above, according to the present invention, a multilayer ceramic porcelain element can be obtained by a relatively easy manufacturing method which is easy in terms of process and can be put into practical use, and has a very large practical effect. is there.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a configuration of a laminated ceramic porcelain element according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part, illustrating a manufacturing method according to the embodiment.

[Explanation of symbols]

 1 ceramic sheet 2 internal electrode layer 3 external electrode

Continuation of front page (56) References JP-A-2-222127 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4/42

Claims (1)

(57) [Claims] The main component of the ceramic layer is SrTiO ₃ or Sr in which a part of Sr is replaced by Ca, Mg, Ba or a mixture thereof, and the main components of the internal electrode and the external electrode are Ag, Pd, Ni, Cu, Zn, In, Ca, N
a method of manufacturing a laminated ceramic porcelain element comprising at least one of a, K, and Li, or an alloy or a mixture thereof;
It so that the layers are interleaved through the ceramic layers
A plurality of layers are laminated, and external
The external electrode of a laminated ceramic porcelain element provided with poles
Activated under atmospheric pressure or reduced pressure after plating parts
Leave in high-concentration aqueous solution and release into ion-exchanged water.
Manufacturing method of a laminated ceramic porcelain element to be placed.