JPH07220906A - Multifunction element - Google Patents

Abstract

PURPOSE:To suppress layer separation and delamination and cracks by adding BiO2O3 and glass formations to a semiconductor ceramic part and a magnetic substance ceramic part. CONSTITUTION:Bi2O3 and glass compound are added to varistor sheets 1a, 1b and 1c and ferrite sheets 3a, 3b and 3c. The glass compound can be zinc borosilicate, bismuth borosilicate, lead borosilicate, or a their oxide. The amount of Bi2O3 and the glass formation is 10wt.% or less. Metallic patterns 2a and 2b are printed on the varistor sheets 1b and 1c, and a metallic pattern 2c is printed on the ferrite sheet 3b. Following this, the varistor sheets 1a, 1b and 1c and the ferrite sheets 3a, 3b and 3c are laminated successively, compressed, cut into a specified size, and sintered to obtain a multifunction element 4. As a result of this, reaction and mutual diffusion of individual formations are suppressed, and layer separation, etc., are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-functional device having both varistor characteristics, capacitor characteristics and magnetic characteristics.

[0002]

2. Description of the Related Art A semiconductor device such as an IC may be destroyed or malfunction due to transient noise such as static electricity. As a method of preventing these noises, a set or a ground of the board is set, or an element array in the board or a noise absorbing element such as a varistor or an LC filter is used.

Of these, the method of using an element such as a varistor is relatively simple and is often performed as a measure against noise. For the purpose of protection from these noises,
The varistor voltage needs to be as close to the circuit voltage as possible, and it is desired to reduce the voltage. Further, a chip-type component having a small element size and capable of surface mounting is desired due to miniaturization of the device.

[0004]

An electronic component which addresses these problems is disclosed in Japanese Patent Publication No. 58-23921. However, the electronic component described in Japanese Patent Publication No. 58-23921 has the same limiting voltage as that of the conventional varistor, and further voltage suppression capability is required for circuit protection.

Also, in order not to generate noise from various devices or to prevent noise from entering various devices,
Ferrite chips and capacitors are attached to the input / output parts of each device to prevent electromagnetic noise, but adding these parts requires many parts, increasing the board area and complicating the process. However, there is a problem in that it leads to cost increase.

Therefore, a semiconductor device composition having a varistor characteristic and a magnetic ceramic composition are joined and integrated to provide a multi-functional device which solves the above-mentioned problems. However, since this composite functional element bonds different material compositions, it is necessary to control the shrinkage and reaction of these compositions.

The object of the present invention is to suppress layer peeling, delamination and cracks caused by joining a semiconductor porcelain composition and a magnetic porcelain composition, and by joining them together, a ferrite chip and a capacitor are integrated. An object of the present invention is to provide a multi-functional element that is a reduced electromagnetic noise countermeasure component.

[0008]

The invention according to claim 1 is
In a composite element obtained by joining a semiconductor porcelain having varistor characteristics and a magnetic material porcelain and integrally sintering, the semiconductor porcelain portion and the magnetic porcelain portion have a composite function containing Bi ₂ O ₃ and a glass composition. It is an element.

In a second aspect of the invention, the glass composition is zinc borosilicate, bismuth borosilicate, lead borosilicate or a composite oxide thereof.

In the invention according to claim 3, the semiconductor porcelain is Zn
O-based, Bi ₂ O ₃ and glass composition 10 wt%
It is a compound functional element containing the following (excluding 0 wt%).

In the invention according to claim 4, the magnetic porcelain is made of nickel-zinc-iron-based ferrite, and Bi ₂ O ₃ and the glass composition are 10 wt% or less (excluding 0 wt%).
It is a multi-functional element contained.

[0012]

By adding Bi ₂ O ₃ and the glass composition to the semiconductor porcelain portion or the magnetic porcelain portion, layer peeling, delamination, cracks, and porcelain mutual interference that occur when these different material compositions are joined It is possible to suppress the reaction of.

[0013]

【Example】

[Preparation of Varistor Material] As raw materials, ZnO, Bi ₂ O ₃ , CoCO ₃ , MnO and Sb ₂ O having a purity of 99% or more are used.
₃ was weighed in proportions of 98 mol%, 0.5 mol%, 0.5 mol%, 0.5 mol% and 0.5 mol%, respectively, and the glass composition having the composition shown in Table 1 was used. Using 0
It was weighed and added in the range of wt% to 15 wt%. Note that Bi
₂ O ₃ is contained in an amount of 2.8 wt% in terms of wt%. Pure water was added to this raw material and mixed by a ball mill for 24 hours to obtain a mixture slurry. Next, the obtained slurry was filtered, dried, granulated, and then calcined at a temperature of 800 ° C. for 2 hours.

[0014]

[Table 1]

Further, the calcined product was coarsely crushed, pure water was added, and finely crushed with a ball mill. The slurry thus obtained was filtered and dried, and then dispersed in a solvent together with an organic binder to obtain a slurry. A sheet having a thickness of 50 μm was prepared from the obtained slurry by the doctor blade method. This sheet was punched out to obtain a plurality of green sheets.

[Preparation of Ferrite Material] Fe ₂ O ₃ , NiO and ZnO each having a purity of 99% or more are used as raw materials.
7 mol%, 30 mol% and 23 mol% were weighed, pure water was added and mixed by a ball mill for 24 hours to obtain a mixture slurry. The resulting slurry was filtered, dried, granulated, and then calcined at a temperature of 1100 ° C. for 2 hours.

Further, after roughly calcining the calcined product, Bi
₂ O ₃ was added in an amount of 1.0 wt%, a glass composition having a composition as shown in Table 1 was added in an amount of 0 wt% to 15 wt%, pure water was added, and the mixture was mixed and ground in a ball mill for 24 hours. After filtering and drying this slurry, it was dispersed in a solvent together with an organic binder to obtain a slurry. 50 μm from the obtained slurry by the doctor blade method
A sheet having a thickness of 1 was created. This sheet was punched out to obtain a plurality of green sheets.

[Printing / Laminating / Baking of Internal Electrodes] As shown in FIG. 1, the varistor sheet 1a obtained in the above steps,
1b and 1c are prepared, and the ferrite sheet 3
a and 3b were prepared. The varistor sheet 1b was printed with a metal pattern 2a made of a conductive paste, and the varistor sheet 1c was similarly printed with a metal pattern 2b.

On the ferrite sheet 3b, a metal pattern 2c made of a conductive paste was printed. The conductive paste used was silver and palladium in a ratio of 7: 3. The varistor sheet 1a and the ferrite sheet 3a are dummy sheets on which no metal pattern is formed. The conductive paste was printed by a screen printing method.

Further, these printed varistor sheets 1a, 1b, 1c and ferrite sheets 3a, 3b were stacked in the order shown in FIG. 1 and pressure-bonded at a pressure of ² t / cm ² . Cut the crimped body thus made into a predetermined size,
The composite functional element was obtained by firing at 950 ° C. for 2 hours. FIG. 2 is a laminated sectional view of the composite functional element body 4.

As a result of examining the appearance of the element body 4 formed by the above method, layer peeling and delamination occurred depending on the amounts of Bi ₂ O ₃ added to the varistor and ferrite and the glass composition. The results are shown in Table 2. The * mark in Table 2 is outside the scope of the claims of the present invention. The values in parentheses in Table 2 are addition amounts including the Bi ₂ O ₃ amount. Table 2
○ and × indicate the degree of occurrence of layer peeling and delamination of each sample. In Table 2, ◯ indicates that no peeling or delamination of 10 sample middle layers occurred, and x indicates that 5 or more peeling or delamination of 10 sample middle layers occurred.

[0022]

[Table 2]

Next, as shown in FIG. 3, a silver paste was applied to the sample body in which no layer peeling or delamination had occurred, and heat treatment was carried out at 800 ° C. for 10 minutes to form the external electrode 5 and the ground electrode. 6 was formed. FIG. 3 is a perspective view of the multifunctional device.

The samples thus obtained were evaluated for varistor voltage, non-linear coefficient, electrostatic capacity, dielectric loss, inductance and impedance. The test method will be described below. As the varistor voltage, the voltage obtained for a direct current of 1 mA was measured. The non-linear coefficient was obtained by the following formula from the voltage (V _1mA ) obtained for a direct current of 1 _mA and the voltage (V _{10 mA} ) obtained for a direct current of 10 mA. α = 1 / lo
It was calculated from the formula of g (V _10mA / V _1mA ).

Next, capacitance and dielectric loss were measured at a frequency of 1 MHz, 1 Vrms and 25 ° C. using an automatic bridge type measuring device. Inductance is frequency 1MHz, 1Vrms,
It was measured at 25 ° C. Impedance is frequency 100MH
is the resistance value of z. The results of these measurements are shown in Table 3. The mark * in Table 3 is outside the scope of the claims of the present invention. In addition, the numbers with ** are not shown because the data are not reliable.

[0026]

[Table 3]

By incorporating Bi ₂ O ₃ and the glass composition as described above, it becomes possible to perform firing at a low temperature,
The varistor and ferrite shrinkage can be matched by controlling the glass amount. Further, even if Bi ₂ O ₃ and the glass composition are contained, the influence of the glass on the varistor characteristics and the inductance is small and there is no problem. However, the addition amount of Bi ₂ O ₃ and glass is 10 wt%
When it exceeds, the inductance decreases and the high frequency impedance decreases.

In the present invention, as shown in FIG. 1 and FIG.
One layer of ferrite sheet 3, varistor sheet 1a, 1
This is a structure in which three layers b and 1c are arranged on both sides of the ferrite sheets 3a and 3b, and this shows the minimum number of layers necessary for explaining the present invention. The number of laminated varistor sheets 1a, 1b, 1c and ferrite sheets 3a, 3b is arbitrary regardless of the figure. Also, the stacking direction is not limited to that shown in the figure, and the metal patterns 2a, 2b, 2c
Does not stick to the stacking direction unless it contacts the other metal patterns 2a, 2b, 2c.

[0029]

According to the present invention, even if the varistor and the ferrite are integrally sintered, the reaction and mutual diffusion of the respective compositions are suppressed by the Bi ₂ O ₃ and the glass composition.
Layer peeling, delamination, and cracks can be prevented, and an element having a composite function can be formed without impairing the electrical characteristics of each. Furthermore, by combining a varistor and a ferrite, it is possible to provide an electromagnetic noise countermeasure element that includes protection against transient noise and the like. Furthermore, by integrally sintering, a smaller and cheaper element can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a composite function element of the present invention.

FIG. 2 is a laminated cross-sectional view of a composite functional element body of the present invention.

FIG. 3 is a perspective view of a multifunctional device according to the present invention.

[Explanation of symbols]

 1a, 1b, 1c Varistor sheet 2a, 2b, 2c Metal pattern 3a, 3b Ferrite sheet 4 Complex functional element 5 External electrode 6 Earth electrode

Claims (4)

[Claims] 1. In a composite element obtained by joining a semiconductor porcelain having varistor characteristics and a magnetic material porcelain and integrally sintering, the semiconductor porcelain part and the magnetic porcelain part are Bi ₂
A multi-functional device comprising O ₃ and a glass composition. 2. The multifunctional device according to claim 1, wherein the glass composition is zinc borosilicate, bismuth borosilicate, lead borosilicate or a composite oxide thereof. 3. The semiconductor porcelain is made of ZnO, and B
i ₂ O ₃ and glass composition are 10 wt% or less (however, 0
(excluding wt%) is contained.
And the multi-functional device described in 2. 4. The magnetic porcelain is made of nickel-zinc-iron-based ferrite, and Bi ₂ O ₃ and the glass composition are 1
3. The multi-functional element according to claim 1, wherein the content is 0 wt% or less (excluding 0 wt%).