JP3103803B1 - Dielectric porcelain composition and method for producing the same - Google Patents

Abstract

A dielectric porcelain composition that does not contain environmental pollutants such as PbO and Bi ₂ O _{3 and} can be fired at a low temperature without using a glass composition. Further, Ag or Ag is used. Even if an alloy is used as the internal conductor, the dispersion of the dielectric characteristics due to the diffusion of Ag is extremely small, and no microwave is generated between the internal conductor and the dielectric and no draw-in occurs in the external connection conductor of the internal conductor. And a method for producing the same. SOLUTION: The dielectric ceramic composition is represented by a general formula xBaO ·
yNd ₂ O ₃ .zTiO ₂ (provided that 6 ≦ x ≦ 23, 13
≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 100) with respect to the main component represented by 0.1 to 3.0% by weight of Cu oxide as a subcomponent in terms of CuO. Z
0.1 to 4.0% by weight of n oxide in terms of ZnO, 0.1 to 3.0 wt% of B oxide in terms _of B ₂ O _3, the Ag 0.3 to 1.5 wt% Shall be contained within the range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric porcelain composition,
In particular, the present invention relates to a dielectric ceramic composition having low-temperature sinterability such that Ag or an alloy containing Ag as a main component can be used as an internal conductor, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the field of mobile communication such as automobile telephones and portable telephones has been remarkably growing. In these mobile communications,
A high-frequency band called quasi-microwave of 00 MHz to several GHz is used. For this reason, high-frequency characteristics are also emphasized in electronic devices such as resonators, filters, and capacitors used in mobile communication devices. As for the spread of mobile communications in recent years, miniaturization and cost reduction of communication devices have become important factors in addition to the improvement of services. For this reason, the electronic devices described above are also required to be reduced in size and cost.

For example, in a resonator material, the following characteristics (1) to (4) are required at a working frequency in order to achieve an improvement in high-frequency characteristics and a reduction in size. (1) Large relative permittivity: A resonator used near microwaves often utilizes the fact that the wavelength in a dielectric is shortened in proportion to the reciprocal of the square root of the permittivity. The length of the vessel can be shortened in proportion to the reciprocal of the square root of the permittivity. (2) Large Q: In a microwave material, Q defined by Q = 1 / tan δ is used for evaluation of dielectric loss.
A large Q indicates a small loss. (3) A small change in the permittivity with temperature: It is desirable that the change in the permittivity with temperature is small in order to minimize the change in the temperature of the resonance frequency of the resonator or the filter. (4) Low-temperature sintering is possible: In order to realize the miniaturization of electronic devices, surface-mount components (S
Although MD (Surface Mount Device) is becoming mainstream, it is desirable to use low-resistance Ag or Cu as the internal conductor electrode in order to improve the loss characteristics of the electronic device. However, Ag and Cu have low melting points, and the dielectric ceramic composition used is required to be capable of sintering at a temperature lower than these melting points. The problem of simultaneous sintering is also pointed out when a temperature compensating capacitor material using Ag, Cu or the like as an internal conductor electrode is used.

Conventionally, as a material of the dielectric ceramic for microwave, BaO-4TiO ₂ system, BaO-rare earth oxide -
Composition systems such as TiO ₂ are well known. In particular, Ba
The O—Nd ₂ O ₃ —TiO ₂ system has been extensively studied because of its high dielectric constant and Q value. In recent years, low-temperature sintering with this composition system has also been carried out.
No. 722 (after calcination of the main component, pulverized to a predetermined particle size,
Patent No. 2781500).
No. 2,781,501, Patent No. 2,781,502
Nos. 2,781,503 and 2,786,977 (these use glass as an auxiliary component); JP-A-5-234420, JP-A-6-211564, JP-A-6-223625, and JP-A-6-223625. 7-697
No. 19, JP-A-8-55518, JP-A-8-55518
55519, JP-A-8-167322, JP-A-8-167323, JP-A-8-167324
JP-A-8-208328, JP-A-8-208328
08329 (these contain glass as an auxiliary component); JP-A-3-290359, JP-A-3-290.
295854, JP-A-3-295855,
JP-A-3-295856, JP-A-6-11602
No. 3, JP-A-6-150719, JP-A-6-150719
JP-A-162822, JP-A-8-55518, JP-A-8-167322, JP-A-8-167323
JP-A-8-167324, JP-A-8-167324
JP-A-08328, JP-A-8-208329, and JP-A-8-245262 (these contain a Ge oxide as an auxiliary component);
07, JP-A-2-44609, and JP-A-5-
97508, JP-A-6-116023, JP-A-8-157257, JP-A-8-277161
No., etc.

[0005] These things, which mostly a main component BaO- rare earth oxide -TiO _2, which the glass composition, or a low temperature in a manner of adding the glass composition and several sub-components Sintering is possible. Many of the above-mentioned dielectric materials contain PbO, Bi ₂ O _3, or the like in the main component or the additive component. This is Pb
O and Bi ₂ O ₃ have a low-temperature sintering assisting effect as well as a property improving effect such as an increase in dielectric constant. By utilizing both of these effects, a low-temperature sintering high-frequency material is made possible. That's why.

[0006]

SUMMARY OF THE INVENTION As described above, BaO
-Nd ₂ O ₃ -TiO ₂ based dielectric ceramic has a dielectric constant and the Q is high, since the temperature coefficient of the dielectric constant is small, are used as a microwave dielectric. In particular, in recent years, low-temperature sintering in the BaO—Nd ₂ O ₃ —TiO ₂ system has been realized, but most of them have been described above for the purpose of improving characteristics and promoting low-temperature sintering. PbO, Bi
Contains at least one of ₂ O ₃ .

[0007] In recent years, however, the global environmental protection movement has been increasing. Therefore, reduction of environmental pollutants such as PbO and Bi ₂ O ₃ is demanded also in the field of electronic components. In addition, when such an environmental pollutant is contained, special facilities such as a waste liquid treatment facility in a manufacturing process are required, and it is desired not to contain an environmental pollutant from the viewpoint of production cost. Further, since PbO, Bi ₂ O _{3, and the} like are substances that easily evaporate at high temperatures, they tend to cause variations in quality at the time of manufacturing, and from this point, it is desired that PbO, Bi ₂ O ₃ be not contained. I have.

As described above, most of the conventional dielectric porcelain compositions essentially require a glass composition as an additive for sintering, but a predetermined glass is prepared in advance. This necessitates an increase in cost due to an increase in the number of manufacturing steps and an increase in unstable factors. In addition, when producing glass, the composition of the glass is restricted by vitrification conditions, so that an optimum composition cannot always be obtained, which causes deterioration of the characteristics of the dielectric ceramic. On the other hand, studies have been made on dielectric porcelain without addition of glass, but most of them require firing at a temperature of 1000 ° C. or higher, and thus, for example, cannot use Ag as an internal conductor. There was a problem.

Further, the conventional dielectric porcelain composition is made of Ag
Is fired as an internal conductor, Ag of the internal conductor diffuses into the dielectric. Since the diffusion of Ag occurs due to the concentration gradient of Ag, the concentration of Ag inside the dielectric is not uniform. For example, the Ag concentration is high around the Ag conductor, and the Ag concentration is low at a portion away from the Ag conductor. A concentration distribution results. When Ag diffuses into the dielectric in this manner, the dielectric properties change depending on the concentration,
An electronic component using Ag as an internal conductor has different dielectric characteristics depending on the portion, and cannot provide desired device characteristics, causing a problem such as a variation in device characteristics. Further, the diffusion of Ag into the dielectric reduces the amount of Ag in the internal conductor, thereby failing to obtain desired device characteristics and causing variations in device characteristics.

Further, when the amount of Ag diffused from the inner conductor into the dielectric is large, a gap is formed between the inner conductor and the dielectric, or the conductor portion for connection to the outside is pulled in, and the conduction is reduced. It causes a defect such as a defect. Especially in recent years, the miniaturization of high-frequency components has been rapidly progressing, and with this, the fine patterning and thinning of the internal conductor have also been progressing, so the gap between the internal conductor and the dielectric substrate,
The drawback caused by drawing in the external connection portion of the internal conductor is a serious problem.

The present invention has been made in view of such circumstances, and does not contain environmental pollutants such as PbO and Bi ₂ O _{3 and} can be sintered at a low temperature without using a glass composition. A dielectric porcelain composition, further comprising Ag or A
Even when the g alloy is used as the internal conductor, the dispersion of the dielectric properties due to the diffusion of Ag is extremely small, and no voids are generated between the internal conductor and the dielectric, and no pull-in occurs in the external connection conductor of the internal conductor. An object of the present invention is to provide a dielectric porcelain composition capable of forming a wave dielectric porcelain, and a method for producing the same.

[0012]

In order to achieve the above object, the dielectric ceramic composition of the present invention has a main component represented by a general formula xBaO.yNd ₂ O ₃ .zTiO ₂ (where 6 ≦ x
≦ 23, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z
= 100), and a Cu oxide as a subcomponent with respect to the main component is 0.1 to 3.0 in terms of CuO.
% By weight, Zn oxide 0.1 to 4.0% by weight in terms of ZnO, B oxide 0.1 to 3.0% by weight in terms of B ₂ O ₃ , A
g in the range of 0.3 to 1.5% by weight.

The method for producing the dielectric porcelain composition of the present invention comprises:
After mixing the respective raw materials of BaO, Nd ₂ O ₃ and TiO ₂ , 1
Calcination is performed at a temperature of 100 ° C or higher, and the general formula xBaO
yNd ₂ O ₃ .zTiO ₂ (provided that 6 ≦ x ≦ 23, 13
≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 100), and Cu oxide as a sub-component of 0 in CuO conversion as a sub-component with respect to the base material powder. 0.1 to 3.0 wt%, Zn oxide is 0.1 to 4.0 wt% in terms of ZnO, and B oxide is 0.1 in terms of B ₂ O _3.
A powder obtained by mixing Ag powder in a range of 0.3-1.5% by weight and Ag in a range of 0.3-1.5% by weight is calcined again at a temperature not higher than the sintering temperature of the powder. And a step of pulverizing to a particle size of

Further, the method for producing a dielectric ceramic composition of the present invention is characterized in that, after mixing each of BaO, Nd ₂ O ₃ and TiO ₂ , the mixture is calcined at a temperature of 1100 ° C. or higher to obtain a general formula xB
_{aO · yNd 2 O 3 · zTiO} 2 ( however, 6 ≦ x ≦ 2
3, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 1
And a Cu oxide as a sub-component with respect to the matrix powder.
0.1 to 3.0% by weight in terms of uO, Zn oxide is ZnO
0.1 to 4.0 wt% in terms of, B oxide B ₂ O ₃ The mixed powder to be in the range of 0.1 to 3.0 wt% in terms of powder of sintering temperature below the temperature After calcining again, Ag is further added to the calcined powder as a subcomponent so as to be in a range of 0.3 to 1.5% by weight based on the base material powder.
Pulverizing to a predetermined particle size.

Further, in the method for producing a dielectric ceramic composition according to the present invention, the additive form of Ag as a sub-component may be metal Ag powder, AgN
The structure was such that it was at least one of O ₃ , Ag ₂ O and AgCl, and the first calcining was performed at a predetermined temperature in the range of 1100 to 1350 ° C.

According to the present invention, a Cu oxide, a Zn oxide and a B oxide added in a predetermined content together with a BaO—Nd ₂ O ₃ —TiO ₂ main component in a predetermined composition range are provided.
By the oxide, the sintering temperature of the dielectric porcelain composition becomes equal to or lower than the melting point of Ag or an alloy containing Ag as a main component while the dielectric properties are substantially maintained. Has the effect of suppressing the diffusion of Ag into the dielectric when Ag or an Ag alloy is used as the internal conductor.

[0017]

Next, an embodiment of the present invention will be described.

Dielectric Ceramic Composition The dielectric ceramic composition of the present invention has a general formula xBaO.yNd
_It contains Cu oxide, Zn oxide, B oxide and Ag as subcomponents with respect to the main component represented by ₂ O ₃ .zTiO ₂ .

The above main component has a composition in which x, y and z satisfy the following relationship. 6 ≦ x ≦ 23 13 ≦ y ≦ 30 64 ≦ z ≦ 68 x + y + z = 100

The content of each subcomponent contained in the main component is set within the following range. Cu oxide: CuO translated at 0.1-3.0 wt% Zn oxide: 0.1 to 4.0 wt% B oxide in terms of ZnO: 0.1-3 in terms _of B ₂ O ₃ 0.0% by weight Ag: 0.3 to 1.5% by weight

The composition range of the main component and the content range of the subcomponent as described above are set based on the dielectric properties targeted in the present invention, which will be described below.

In the present invention, the evaluation of the dielectric properties is based on the low-temperature sinterability, the relative dielectric constant, and the temperature coefficient of the dielectric constant (hereinafter, TCC).
) And Q (1 / tan δ) characteristics are performed as follows.

An object of the present invention is to provide a low-temperature sinterable dielectric porcelain composition for use in an electronic device having Ag or an alloy containing Ag as a main component as an internal conductor. Is the most important property. Specifically, it is determined that a sintered body having a sintered body density of 5.0 g / cm ³ or more after firing at 920 ° C. is practicable.

Relative Dielectric Constant For example, when the dielectric ceramic composition of the present invention is used for a dielectric resonator for high frequency, the length of the resonator depends on the magnitude of the dielectric constant. It is advantageous to have a large dielectric constant in order to achieve a higher dielectric constant. However, the dielectric ceramic composition of the present invention can be used for various electronic devices having Ag or an alloy containing Ag as a main component as an internal conductor, in addition to the above-described dielectric resonator, and has a preferable dielectric constant. Cannot be determined unconditionally. Therefore, the present invention does not particularly consider the value of the dielectric constant.

TCC In the present invention, TCC (ppm / ° C.) is calculated by the following equation. _{TCC = [(C 85 ℃ -C} -25 ℃) / C 25 ℃] × (1/1
10 ° C.) × 10 ⁶ where TCC: temperature coefficient of dielectric constant between −25 ° C. and _{85 ° C.} C _{85 ° C .} : capacitance at 85 ° C. C _{−25 ° C .} : capacitance at _{−25 ° C.} C _{25 ° C .} : at 25 ° C. Capacitance

For example, the dielectric resonator has a TCC of ± 30.
It is preferably within ppm / ° C., the TCC of the dielectric filter is preferably within ± 100 ppm / ° C., and in the case of a capacitor for temperature compensation, the TCC having a wide value has a wider use area. In order to make the dielectric ceramic composition of the present invention applicable to such dielectric resonators, dielectric filters, temperature compensating capacitors, etc., the target of TCC is preferably near 0,
Even if the absolute value of CC is large, there is no particular problem.

As described above, an object of the present invention is to provide a dielectric ceramic composition which can be sintered at a low temperature and is used for an electronic device having Ag or an alloy containing Ag as a main component as an internal conductor. Q
Since a decrease in the characteristics means that the loss of the electronic device increases, a certain degree of Q characteristics is required. Therefore, in the present invention, the target of the Q characteristic is set to 1000 or more.

Low-temperature sinterability evaluated as described above,
The dielectric properties such as the relative dielectric constant, TCC, and Q property are greatly affected by the main component composition of the dielectric ceramic composition, and if the main component composition is out of the above-described composition range of the present invention, the following problems occur. Occurs.

First, if the proportion of BaO is less than 6 mol%, the dielectric constant is lowered and the low-temperature sinterability is also lowered (9).
After firing at 20 ° C., the sintered body density is 5.0 g / cm.
Less than ³ ). Since the decrease in low-temperature sinterability is fatal to the object of the present invention of providing an electronic device having Ag or an alloy containing Ag as a main component as an internal conductor,
The amount of BaO was limited to a range in which low-temperature sinterability could be ensured.
When BaO exceeds 23 mol%, the dielectric constant increases, the low-temperature sinterability improves, the TCC largely shifts to the minus side, and the Q characteristic deteriorates (less than 1000). Since a decrease in the Q characteristic causes an increase in the loss of the electronic device, which is not preferable, the BaO amount is limited to a range in which the Q characteristic can be secured (1000 or more).

Next, when the proportion of Nd ₂ O ₃ is less than 13 mol%, the dielectric constant is increased and the low-temperature sinterability is improved.
Since the TCC and Q characteristics deteriorate (less than 1000), the amount of Nd ₂ O ₃ is limited to a range where the Q characteristics can be ensured. On the other hand, if Nd ₂ O ₃ exceeds 30 mol%, the dielectric constant is lowered and the low-temperature sinterability is lowered (the sintered body density after firing at 920 ° C. is less than 5.0 g / cm ³ ), which is not preferable. .

_{On the} other hand, when the proportion of TiO ₂ is less than 64 mol%, the TCC increases to the positive side and the Q characteristic deteriorates (less than 1000), which is not preferable. on the other hand,
When the proportion of TiO ₂ exceeds 68 mol%, the low-temperature sinterability decreases and the TCC increases to the minus side.
For this reason, the amount of TiO ₂ is limited to a range where low-temperature sintering can be ensured.

If the composition of the sub-components in the dielectric ceramic composition of the present invention is out of the above range, the following problems occur.

First, when the proportion of Cu oxide is less than 0.1% by weight in terms of CuO with respect to the main component, the low-temperature sintering effect of Cu oxide becomes insufficient. Also,
If the content exceeds 3.0% by weight, the Q characteristic is lowered (less than 1000), which is not preferable, and the dielectric constant changes non-linearly with temperature, so that it is difficult to use as an electronic device. In particular, the proportion of the Cu oxide is preferably in the range of 0.5 to 1.5% by weight in terms of CuO with respect to the main component.

On the other hand, if the proportion of Zn oxide is less than 0.1% by weight in terms of ZnO with respect to the main component, the low-temperature sintering effect of the Zn oxide becomes insufficient, which is not preferable. On the other hand, if the content exceeds 4.0% by weight, the low-temperature sinterability does not necessarily improve with an increase in the content. Conversely, the low-temperature sinterability decreases and the dielectric constant and the Q characteristic decrease. This leads to deterioration of characteristics, which is not preferable.

Further, when the proportion of the B oxide is less than 0.1% by weight in terms of B ₂ O _{3 with} respect to the main component, the low-temperature sintering effect of the B oxide becomes insufficient. Also, 3.
If the content exceeds 0% by weight, the low-temperature sinterability does not necessarily improve with an increase in the content. Conversely, the low-temperature sinterability decreases, and the dielectric properties such as a decrease in the dielectric constant and a decrease in the Q characteristic deteriorate. It is not preferable because it causes it.

The reason why the dielectric porcelain composition of the present invention contains Ag as a sub-component is that when Ag or an Ag alloy is used as the internal conductor, the diffusion of Ag from the internal conductor into the dielectric substrate is suppressed. To do that. When the content of Ag as the subcomponent is less than 0.3% by weight with respect to the main component, the above-described suppression of the Ag diffusion is insufficient, and a problem due to the Ag diffusion, for example, the Ag content in the dielectric material Inconsistencies in the dielectric constant cause variations in the dielectric constant, a reduction in the amount of Ag in the internal conductor causes voids between the conductor and the dielectric substrate, and poor conduction due to drawing in of the internal conductor at the connection with the outside. . Also, as the Ag content increases, the dielectric constant tends to increase. However, if the Ag content exceeds 1.5% by weight with respect to the main component, the allowable uptake of Ag diffusion in the dielectric material is increased. , And Ag segregation occurs in the dielectric substrate, which adversely affects reliability such as voltage load life, which is not preferable.

Next, a method for producing the dielectric ceramic composition of the present invention will be described.

First, barium and neodymium, which are the main components,
A titanium oxide is prepared, a predetermined amount is weighed, mixed and calcined. The above mixture has the general formula xBaO.yNd ₂ O ₃
ZTiO ₂ (however, 6 ≦ x ≦ 23, 13 ≦ y ≦ 3
0, 64 ≦ z ≦ 68, and x + y + z = 100). The main component material does not need to be an oxide. For example, when a material that becomes an oxide by heat treatment, such as a carbonate, a hydroxide, or a sulfide, is used. Can be obtained.

The main component materials can be mixed by, for example, wet mixing using water or the like, and the mixing time is 4 to 2 minutes.
It can be set in about 4 hours. The calcination is a step of synthesizing a (BaO-rare earth oxide-TiO ₂ ) compound from a mixture of the main component materials, and is preferably performed at 1100 ° C. or more, preferably 1100 to 1350 ° C. for about 1 to 24 hours.

Next, Cu oxide and Zn oxide as sub-components
Predetermined amounts of the product, B oxide and Ag are weighed and calcined as
Mixed with the main component (base material powder). That is, the base material powder
Cu oxide as a sub-component with respect to powder
0.1 to 3.0% by weight, Zn oxide is 0.1% in terms of ZnO.
1 to 4.0% by weight, B oxide is B_TwoO_Three0.1 ~
3.0% by weight and Ag in the range of 0.3 to 1.5% by weight.
And mix as needed. In addition, also regarding Cu, Zn and B,
Like the component raw materials, it need not be an oxide, for example,
Oxidation by heat treatment such as carbonates, hydroxides, sulfides, etc.
The use of oxides
A dielectric ceramic composition equivalent to the case can be obtained. Ma
In addition, Ag does not need to be metallic Ag.
AgNO _Three, Ag_TwoHeat treatment like O and AgCl
By using a material that becomes metal Ag by
It is possible to obtain the same dielectric ceramic composition as when Ag is used.
Can be. The above mixture of main component and sub-component
For example, it can be performed by wet mixing using water or the like.

Next, the above-mentioned mixed and pulverized material is heated at a temperature lower than its sintering temperature, for example, at 650 to 850 ° C.
The calcining is performed again in about 10 hours, and the calcined powder is pulverized to a predetermined particle size. By performing such recalcination, the main component and the subcomponent can be uniformly dispersed, and a powder having a narrow particle size distribution can be obtained. Can be improved.

With respect to the powder obtained as described above,
After mixing an organic binder such as a polyvinyl alcohol type, an acrylic type, and an ethyl cellulose type, the mixture is molded into a desired shape, and the molded product is fired and sintered. The molding may be wet molding such as a sheet method or a printing method, or dry molding such as a press molding, and a molding method can be appropriately selected according to a desired shape. Further, for example, the firing is desirably performed in an oxygen atmosphere such as in air, and the firing temperature can be set at a temperature equal to or lower than the melting point of Ag or an Ag alloy used as the internal conductor, preferably in a range of 850 to 950 ° C. The firing time is preferably about 0.1 to 24 hours.

Next, another embodiment of the method for producing the dielectric ceramic composition of the present invention will be described. First, oxides of barium, neodymium, and titanium, which are main components, are prepared, weighed and mixed in predetermined amounts, and calcined. The above mixture is also represented by the general formula x
_{BaO · yNd 2 O 3 · zTiO} 2 ( however, 6 ≦ x ≦ 2
3, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 1
(Having a relationship of 00). In addition, the main component material does not need to be an oxide. For example, when an oxide is used even if a material that becomes an oxide by heat treatment, such as a carbonate, a hydroxide, or a sulfide, is used. Can be obtained.

The mixing of the main component materials can be performed by, for example, wet mixing using water or the like, and the mixing time is 4 to 2 minutes.
It can be set in about 4 hours. The calcination is a step of synthesizing a (BaO-rare earth oxide-TiO ₂ ) compound from a mixture of the main component materials, and is preferably performed at 1100 ° C. or more, preferably 1100 to 1350 ° C. for about 1 to 24 hours.

Next, predetermined amounts of Cu oxide, Zn oxide and B oxide as subcomponents are weighed and mixed with the calcined main component (base material powder). That is, Cu oxide as a sub-component with respect to the base material powder is 0.1 to
3.0% by weight, Zn oxide is 0.1 to 4.0 in terms of ZnO.
0 wt%, B oxide is mixed in a range of 0.1 to 3.0 wt% in terms _of B ₂ O _3. Also in this case, similarly to the main components, Cu, Zn, and B do not need to be oxides. For example, those that become oxides by heat treatment, such as carbonates, hydroxides, and sulfides, are used. By doing so, it is possible to obtain a dielectric ceramic composition equivalent to the case where an oxide is used. The mixture of the main component and the subcomponent is, for example,
It can be performed by wet mixing using water or the like.

Next, the above-mentioned mixed and pulverized material is heated at a temperature lower than the sintering temperature, for example, 650 to 850 ° C.
The calcination is performed again in about 10 hours. By performing such recalcination, the main component and the subcomponent can be uniformly dispersed, and a powder having a narrow particle size distribution can be obtained. Can be improved.

Next, a predetermined amount of Ag as an accessory component was weighed and mixed with the calcined powder obtained by the second calcining (0.3 to 1.5% by weight of Ag with respect to the base material powder). And calcined powder is ground to a predetermined particle size.
Regarding Ag, it is not necessary to be metallic Ag, for example,
The use of AgNO ₃ , Ag ₂ O and AgCl, which become metallic Ag by heat treatment, allows the use of metallic Ag.
The same dielectric porcelain composition as in the case of using can be obtained.

With respect to the powder obtained as described above,
After mixing an organic binder such as a polyvinyl alcohol type, an acrylic type, and an ethyl cellulose type, the mixture is molded into a desired shape, and the molded product is fired and sintered. The molding may be wet molding such as a sheet method or a printing method, or dry molding such as a press molding, and a molding method can be appropriately selected according to a desired shape. Further, for example, the firing is desirably performed in an oxygen atmosphere such as in air, and the firing temperature can be set at a temperature equal to or lower than the melting point of Ag or an Ag alloy used as the internal conductor, preferably in a range of 850 to 950 ° C. The firing time is preferably about 0.1 to 24 hours.

The dielectric ceramic composition produced by the production method of the present invention as described above can be sintered at a low temperature below the melting point of Ag or an alloy containing Ag as a main component. For this reason, it is possible to configure an electronic component using a metal having a low melting point, such as Ag or an Ag alloy, which has low resistance, as an internal conductor, and furthermore, Ag contained as a subcomponent is transferred from the internal conductor to the dielectric. Since the Ag diffusion is suppressed, the non-uniformity of the dielectric properties is prevented, and the generation of a gap between the internal conductor and the dielectric and the occurrence of pull-in at the external connection portion of the internal conductor are prevented. Various characteristics can be improved, and miniaturization and cost reduction can be achieved.

Further, in the present invention, since it is not necessary to contain a glass composition as an auxiliary component, it is possible to reduce the cost and reduce the instability factor by reducing the glass manufacturing steps, in addition to improving the dielectric properties. Furthermore, since it does not contain environmental pollutants such as PbO and Bi ₂ O _3, it is possible to provide electronic devices adapted to recent environmental protection requirements, and special equipment such as waste liquid treatment is required. Therefore, the manufacturing cost can be reduced. PbO, B
Although i ₂ O ₃ is a substance that easily evaporates at a high temperature, the present invention does not contain these evaporating substances, so that a dielectric porcelain composition that is effective in removing instability during the manufacturing process can be obtained. .

[0051]

Next, the present invention will be described in more detail with reference to examples.

Example 1 First, B was used as a main component material.
Using aCO ₃ , Nd (OH) ₃ and TiO ₂ , the mixture ratio of BaO, Nd ₂ O ₃ and TiO ₂ after calcination is as shown in the column of main component composition in Table 1 below. It was weighed, pure water was added so as to have a slurry concentration of 30%, and wet-mixed in a ball mill for 16 hours, and then dried. The dried powder is calcined in air (1250 ° C.,
2 hours).

Next, CuO, ZnO, B ₂ O ₃ , and Ag as sub-components were added to the base material powder obtained as described above in proportions shown in the column of sub-component composition in Table 1 below. And pure water was added so as to obtain a slurry concentration of 33%, and wet-mixed in a ball mill for 24 hours.
Dried. The dried powder was again calcined in air (750 ° C., 2 hours). The calcined powder thus obtained was added with pure water so as to have a slurry concentration of 33%, wet-ground with a ball mill for 24 hours, and dried to obtain a dielectric ceramic composition (Samples 1 to 7).

Next, 6 parts by weight of ethylcellulose as a binder and 90 parts by weight of terpineol as a solvent are added to 100 parts by weight of each of the dielectric ceramic compositions obtained as described above, and mixed with a grinder. And dispersed by three rolls to form a dielectric paste. The dielectric paste and the Ag paste were alternately laminated by a screen printing method, and then cut into green chips of 4.5 mm × 3.2 mm. The green chip was fired in air for 2 hours (the firing temperature was 920 ° C.), and then Ag was baked as a terminal conductor to produce a chip capacitor having a structure as shown in FIG. In FIG. 1, the chip capacitor is such that Ag internal conductors 1 and dielectrics 2 are alternately laminated, and the outermost Ag internal conductors 1 are connected to terminal conductors 3 respectively.

Next, for each of the above chip capacitors, the low-temperature sintering property (the sintering density of the dielectric 2 was 5.0 g / cm).
³ or more as a practical level), dielectric constant ε, Q (= 1 / t
an δ) and TCC (temperature coefficient of dielectric constant from −25 ° C. to 85 ° C.), and the results are shown in Table 1 below.
In Table 1, the unit of sintering density is (g / cm ³ ), the dielectric constants ε and Q are dimensionless, and the unit of TCC is (ppm / ° C.).

Further, the chip capacitors manufactured using the dielectric ceramic compositions of Samples 1 and 5 were polished to the Ag internal conductor 1 (at the location indicated by the dashed arrow in FIG. 1B), and the Ag internal conductor was polished. The Ag concentration distribution according to the distance from 1 was analyzed by WDS (Wavelength Dispersive Spectrometer) using EPMA (Electron Probe Micro Analyzer), and the results are shown in FIG.

[0057]

[Table 1] As shown in Table 1, low-temperature sinterability, dielectric constant ε, Q characteristic, and TCC
All levels are practically acceptable. However, the dielectric constant ε, which is the most important factor when designing a high-frequency device, increases as the Ag content increases.

Here, as shown in FIG. 2, in the chip capacitor manufactured using the dielectric ceramic composition containing no Ag (sample 1), Ag diffuses from the internal conductor 1 into the dielectric 2. A in the dielectric body near the inner conductor 1
There is a concentration distribution in which the Ag concentration decreases as the g concentration increases and the distance from the internal conductor 1 increases. On the other hand, in the chip capacitor manufactured using the dielectric ceramic composition of the present invention (sample 5) containing a predetermined amount of Ag, the Ag concentration in the dielectric body is substantially uniform, and the It was confirmed that the diffusion of Ag was suppressed. As described above, in the chip capacitor manufactured using the dielectric porcelain composition containing no Ag (sample 1), the concentration distribution of Ag is generated in the dielectric base material. There is also a dielectric constant distribution. For this reason, it is difficult for a dielectric ceramic composition containing no Ag to obtain device characteristics as designed.
However, in a chip capacitor manufactured using the dielectric ceramic composition of the present invention containing a predetermined amount of Ag, diffusion of Ag from the internal conductor is suppressed, and the Ag concentration becomes substantially uniform. Variations in dielectric characteristics can be made extremely small, and device characteristics as desired design values can be achieved.

Next, a green chip for a continuity test is prepared by a screen printing method in the same manner as in the above-mentioned chip capacitor, baked in air at 920 ° C. for 2 hours, and then baked with Ag as a terminal conductor. , An inner conductor 1 (width W = 100 μm) and a dielectric 2 as shown in FIG.
A sample for continuity test provided with the terminal conductor 3 was prepared. The continuity between the terminal conductors 3 at both ends of the continuity test sample was measured with a tester, and the continuity failure rate is shown in Table 2 below. In addition, the continuity test sample was polished to the position of the internal conductor 1 and the size G of the void generated at the end of the internal conductor 1 as shown in FIG. 4 was measured. .

[0060]

[Table 2] As shown in Table 2, the gap generated between the inner conductor 1 and the dielectric 2 decreases as the Ag content of the dielectric ceramic composition used increases. From this, by containing Ag in the dielectric ceramic composition, the diffusion of Ag from the internal conductor is suppressed, and a defect (change in the area of the internal conductor pattern,
It has been confirmed that variation in device characteristics due to a change in the amount of electromagnetic coupling can be reduced, and device characteristics as designed can be stably obtained. Also, from the result of the conduction failure rate, the content of Ag was less than 0.3% by weight (sample 1,
In the case of 2), it is apparent that at the connection portion of the internal conductor 1 with the terminal conductor 3, the internal conductor is pulled in due to the diffusion of Ag, resulting in poor conduction. But A
When g is contained in an amount of 0.3% by weight or more, the diffusion of Ag from the internal conductor 1 is suppressed, whereby the pull-in of the connection portion of the internal conductor 1 with the terminal conductor 3 is suppressed, and as a result, poor conduction is prevented. Is done. However, when the Ag content exceeds 1.5% by weight (Sample 7), there is no problem in both the capacitor characteristics and the conduction, but the Ag content in the dielectric material exceeds the limit and the extreme Ag content is exceeded. Segregation occurs, which adversely affects the life of the capacitor.

Example 2 BaCO was used as a main component material.
_3, using a Nd (OH) ₃ and TiO _2, Ba after calcination
The mixture was weighed so that the mixing ratio of O, Nd ₂ O ₃ and TiO ₂ was as shown in the column of main component composition in Table 3 below, and pure water was added so as to have a slurry concentration of 30%. Wet mixed for 16 hours and then dried. The dried powder is calcined in air (1250 ° C, 2 hours)
Was done.

Next, CuO, ZnO, B ₂ O ₃ , AgN as subcomponents were added to the base material powder obtained as described above.
O ₃ (converted as Ag) was weighed so as to have the ratio shown in the subcomponent composition column in Table 3 below, and pure water was added so that the slurry concentration was 33%.
Wet mixed for hours and then dried. The dried powder was again calcined in air (750 ° C., 2 hours). The calcined powder thus obtained was subjected to slurry concentration 3
Pure water was added to a concentration of 3%, and the mixture was wet-ground with a ball mill for 24 hours, then dried and dried to obtain a dielectric ceramic composition (samples 8 to 1).
3) was obtained.

Next, a dielectric paste was prepared in the same manner as in Example 1 using each of the dielectric ceramic compositions obtained as described above. Using this dielectric paste and Ag paste, a chip capacitor having a structure as shown in FIG. 1 and a sample for a continuity test as shown in FIG. 3 were produced in the same manner as in Example 1.

Next, for each of the above chip capacitors, as in Example 1, low-temperature sintering (the density of the dielectric 2 is 5.0 g / cm ³ or more as a practical level), dielectric constants ε and Q ( = 1 / tan δ) and TCC (−25 ° C.)
To 85 ° C.) and the results are shown in Table 3 below. The conduction failure rate of the sample for the conduction test was measured in the same manner as in Example 1, and the results are shown in Table 4 below.

[0065]

[Table 3] From the evaluation results of the chip capacitors shown in Table 3, the low-temperature sinterability, the dielectric constant ε, the Q characteristic, and the TCC are all at levels that do not pose any practical problems irrespective of the content of Ag as a subcomponent. However, even in this case, the dielectric constant ε, which is the most important factor when designing a high-frequency device, increases as the Ag content increases. And, in the chip capacitor manufactured using the dielectric ceramic composition having insufficient Ag content (sample 8),
An Ag concentration distribution as shown in FIG. 2 is generated in the dielectric substrate, and at the same time, a dielectric constant distribution is also generated.
Is not contained or the content is insufficient (0.3
It was confirmed that it was difficult to obtain device characteristics as designed with a dielectric porcelain composition of less than 10% by weight.

[0066]

[Table 4] From the results of the conduction failure rate shown in Table 4, A
Even when the addition form of g was changed, as in Example 1, when the Ag content was less than 0.3% by weight (sample 8), the internal conductor 1
It is clear that at the connection portion with the terminal conductor 3, the internal conductor caused by the diffusion of Ag occurs and the poor conduction occurs. However, when 0.3% by weight or more of Ag is contained, diffusion of Ag from the internal conductor 1 is suppressed,
As a result, pulling in of the connection portion between the internal conductor 1 and the terminal conductor 3 is suppressed, and as a result, poor conduction is prevented. However, when the Ag content exceeds 1.5% by weight (Sample 13), there is no problem in both the capacitor characteristics and conduction, but the limit of the amount of Ag taken into the dielectric material is exceeded, Ag segregation occurs, adversely affecting the life of the capacitor.

As described above, the addition form of Ag was changed to AgNO.
It was confirmed that the same effect as in the case of adding as Ag powder was obtained also when changing to ₃ .

Example 3 As a main component material, BaCO
_3, using a Nd (OH) ₃ and TiO _2, Ba after calcination
The mixture was weighed so that the mixing ratio of O, Nd ₂ O ₃ and TiO ₂ was as shown in the column of main component composition in Table 5 below, pure water was added so as to have a slurry concentration of 30%, and the mixture was ball-milled. Wet mixed for 16 hours and then dried. The dried powder is calcined in air (1250 ° C, 2 hours)
Was done.

Then, CuO, ZnO, and B ₂ O ₃ as sub-components are respectively in the proportions shown in the column of sub-component composition in Table 5 below with respect to the base material powder obtained as described above. And pure water was added so as to obtain a slurry concentration of 33%, and wet-mixed in a ball mill for 24 hours, and then dried. The dried powder was again calcined in air (750 ° C., 2 hours). To the calcined powder thus obtained, Ag weighed so as to have a ratio shown in the subcomponent composition column in Table 5 below with respect to the base material powder was added, and pure water was added so that the slurry concentration was 33%. With a ball mill 2
After wet pulverization for 4 hours, it was dried to obtain a dielectric ceramic composition (samples 14 to 19).

Next, using each of the dielectric ceramic compositions obtained as described above, a dielectric paste was prepared in the same manner as in Example 1, and this dielectric paste and Ag paste were used. A chip capacitor having a structure as shown in FIG. 1 and a sample for a continuity test as shown in FIG.

Next, for each of the above-mentioned chip capacitors, similarly to Example 1, low-temperature sintering (the density of the dielectric 2 is 5.0 g / cm ³ or more as a practical level), dielectric constants ε and Q ( = 1 / tan δ) and TCC (−25 ° C.)
To 85 ° C.), and the results are shown in Table 5 below. Further, the conduction failure rate of the sample for the conduction test was measured in the same manner as in Example 1, and the results are shown in Table 6 below.

[0072]

[Table 5] From the evaluation results of the chip capacitors shown in Table 5, the low-temperature sinterability, the dielectric constant ε, the Q characteristic, and the TCC are all at levels that do not pose any practical problems regardless of the content of Ag as a subcomponent. However, even in this case, the dielectric constant ε, which is the most important factor when designing a high-frequency device, increases as the Ag content increases. In the chip capacitor manufactured using the dielectric porcelain composition having insufficient Ag content (sample 14), the Ag concentration distribution as shown in FIG. 2 occurs in the dielectric substrate, and at the same time, A dielectric constant distribution also occurs, and Ag
Is not contained or the content is insufficient (0.3
It was confirmed that it was difficult to obtain device characteristics as designed with a dielectric porcelain composition of less than 10% by weight.

[0073]

[Table 6] From the results of the conduction failure rate shown in Table 6, A
Even if the addition time of g is changed, as in Example 1, when the Ag content is less than 0.3% by weight (sample 14), the diffusion of Ag at the connection portion of the inner conductor 1 with the terminal conductor 3 is performed. It is evident that the internal conductor is pulled in due to the above phenomenon, resulting in poor conduction. However, when Ag is contained in an amount of 0.3% by weight or more, the diffusion of Ag from the internal conductor 1 is suppressed, whereby the connection of the internal conductor 1 with the terminal conductor 3 is suppressed, resulting in poor conduction. Is prevented. However, when the Ag content exceeds 1.5% by weight (sample 19), there is no problem in both the capacitor characteristics and the conduction, but the Ag in the dielectric substrate is not affected.
Exceeding the limit of the amount of incorporation, extreme segregation of Ag occurs,
It adversely affects the life of the capacitor.

As described above, regarding the timing of adding Ag, even if it is added in the pulverizing step after the second calcining, the same effect as in the case of adding simultaneously with other subcomponents (Examples 1 and 2). Was confirmed to be played.

Example 4 BaCO was used as a main component material.
_3, using a Nd (OH) ₃ and TiO _2, after calcination B
aO, Nd ₂ O _3, and TiO ₂ were weighed so that the mixing ratio was as shown in the column of main component composition in Table 7 below,
Pure water was added to a slurry concentration of 30%, and the mixture was wet-mixed in a ball mill for 16 hours, and then dried. The dried powder was calcined in air (1250 ° C., 2 hours).

Then, CuO, ZnO, B ₂ O ₃ , Ag as sub-components were added to the base material powder obtained as described above.
Were weighed so as to have the ratios shown in the column of the subcomponent composition in Table 7 below, pure water was added so as to have a slurry concentration of 33%, and wet-mixed in a ball mill for 24 hours, and then dried. The dried powder was again calcined in air (750 ° C., 2 hours). Pure water was added to the calcined powder thus obtained so as to have a slurry concentration of 33%, wet-pulverized by a ball mill for 24 hours, and dried to obtain dielectric ceramic compositions (samples 20 to 48).

Next, a dielectric paste was prepared in the same manner as in Example 1 using each of the dielectric ceramic compositions obtained as described above, and the dielectric paste and the Ag paste were used in the same manner as in Example 1. A chip capacitor having a structure as shown in FIG. However,
Sample 20 had a firing temperature of 1300 ° C.

Next, for each of the above-mentioned chip capacitors, as in Example 1, low-temperature sintering (the density of the dielectric 2 is 5.0 g / cm ³ or more as a practical level), dielectric constants ε and Q ( = 1 / tan δ) and TCC (−25 ° C.)
From 85 ° C. to 85 ° C.), and the results are shown in Table 7 below.

[0079]

[Table 7] As shown in Table 7, when CuO and B ₂ O ₃ are contained but ZnO is not contained (Samples 21 to 25), 9
The sintering density at 20 ° C. becomes less than 5.0 g / cm ³ , and the desired low-temperature sinterability cannot be secured. Further, according to the conventional known technology, it is considered that the content of B ₂ O ₃ is most effective in improving the low-temperature sinterability. However, samples 21-
As is clear from the results of FIG. 25, even when the content of B ₂ O ₃ is increased, the improvement in low-temperature sinterability is confirmed up to a content of 1.5% by weight. Has limitations. Further, when the content of B ₂ O ₃ is increased, the low-temperature sinterability decreases. From the above, CuO, B
It was confirmed that the desired low-temperature sinterability could not be ensured only by containing ₂ O ₃ and Ag. On the other hand, CuO, Zn
Even if O, B ₂ O ₃ and Ag are contained, when the content of B ₂ O ₃ exceeds 3% by weight (sample 41), the sintered density at 920 ° C. becomes less than 5.0 g / cm ^3. As a result, the desired low-temperature sinterability cannot be secured.

On the other hand, CuO,
When ZnO, B ₂ O ₃ and Ag are contained (Samples 26 to 26)
31, 32-40), even at a firing temperature of 920 ° C,
The sintering density becomes the target of 5.0 g / cm ³ or more. Looking at the dielectric characteristics at this time, the Q characteristics are also high (10
(00 or more) It was confirmed that a practically sufficient dielectric ceramic could be obtained. Furthermore, focusing on the dielectric constants ε and TCC, since these are hardly affected by the change in the content of ZnO or B ₂ O ₃ , the present invention maintains the dielectric properties of the main component composition while maintaining the dielectric properties of ZnO and BCC. It was confirmed that the effect of improving the low-temperature sinterability by the inclusion of ₂ O ₃ was obtained.

However, the improvement of the low-temperature sinterability by ZnO does not increase as the ZnO content increases. For example, CuO is 1% by weight, B ₂ O ₃ is 1% by weight, and Ag is 0.5% by weight. When the ZnO content is about 2 wt% (sample 28), the low-temperature sinterability is the best (the sintering density is maximum) when the ZnO content is about 2 wt% (sample 28). And further Zn
When the O content increases, the low-temperature sinterability gradually decreases, and Z
When the nO content exceeds 4% by weight (sample 31), 920
As a result, the sintering density at a temperature of less than 5.0 g / cm ³ is not attained, and the desired low-temperature sinterability cannot be secured.

[0082] In addition, improvement in low-temperature sintering property by the above-described B ₂ O ₃ is, B ₂ O ₃ content of not larger with increasing, for example, 1 wt% of CuO, 2 wt% of ZnO,
When 0.5% by weight of Ag is contained (samples 32, 34, 3
7, 39 to 41), when the B ₂ O ₃ content is about 1.5 to 2% by weight (samples 37 and 39), the low-temperature sinterability is the best (the sintering density is maximum). When the B ₂ O ₃ content further increases, the low-temperature sinterability gradually decreases. As described above, when the B ₂ O ₃ content exceeds 3% by weight (sample 4).
1) Since the sintering density at 920 ° C. is less than 5.0 g / cm ³ , a desired low-temperature sintering property cannot be secured.

Further, when B ₂ O ₃ , ZnO and Ag are contained but CuO is not contained (sample 42), 92
The sintering density at 0 ° C. is less than 5.0 g / cm ³ , and the desired low-temperature sintering property cannot be secured. But B
_When CuO is contained in the range of the present invention in addition to ₂ O ₃ , ZnO and Ag (samples 43 to 47), the target sintering density is 5.0 g / cm even at a firing temperature of 920 ° C.
³ or more. Such an effect of improving the low-temperature sinterability by CuO increases as the content of CuO increases (the sintering density increases). In addition, the dielectric characteristics at this time were found to have a Q characteristic of 1000 or more, which is the target, and thus it was confirmed that a practically sufficient dielectric ceramic could be obtained. On the other hand, since the dielectric constant ε and TCC are hardly affected by the change in the content of CuO, in the present invention, while maintaining the dielectric properties of the main component composition, Cu
It was confirmed that the effect of improving the low-temperature sinterability by the O content was obtained.

However, when the CuO content exceeds the range of the present invention, that is, 3% by weight (sample 48), the Q characteristic is rapidly lowered, and a desired dielectric porcelain cannot be obtained.

As described above, CuO, Z
nO, B ₂ O _3, within the scope of the present invention the Ag (CuO content 0.1 to 3.0 wt%, ZnO content of 0.1 to 4.0 wt%, B ₂ O ₃ content of 0.1 To 3.0% by weight and an Ag content of 0.3 to 1.5% by weight).
It has been clarified that a dielectric ceramic composition having a low-temperature sintering property at a melting point of not more than g can be obtained, and by using this, a dielectric ceramic having practically sufficient dielectric properties can be produced.

Example 5 As a main component material, BaCO
_3, using a Nd (OH) ₃ and TiO _2, after calcination B
aO, Nd ₂ O _3, and TiO ₂ were weighed so that the mixing ratio was as shown in the column of main component composition in Table 8 below.
Pure water was added to a slurry concentration of 30%, and the mixture was wet-mixed in a ball mill for 16 hours, and then dried. The dried powder was calcined in air (1250 ° C., 2 hours).

Next, CuO, ZnO, B ₂ O ₃ , Ag as subcomponents were added to the base material powder obtained as described above.
Were weighed so as to have the proportions shown in the column of the subcomponent composition in Table 8 below, pure water was added so that the slurry concentration was 33%, and the mixture was wet-mixed with a ball mill for 24 hours, and then dried. The dried powder was again calcined in air (750 ° C., 2 hours). Pure water was added to the calcined powder thus obtained so as to have a slurry concentration of 33%, wet-ground with a ball mill for 24 hours, and dried to obtain dielectric ceramic compositions (samples 49 to 76).

Next, using each of the dielectric ceramic compositions obtained as described above, a dielectric paste was prepared in the same manner as in Example 1, and the dielectric paste and the Ag paste were used to prepare the dielectric paste. A chip capacitor having a structure as shown in FIG.

Next, for each of the above-mentioned chip capacitors, as in Example 1, low-temperature sintering (the density of the dielectric 2 is 5.0 g / cm ³ or more as a practical level), dielectric constants ε and Q ( = 1 / tan δ) and TCC (−25 ° C.)
From 85 ° C.), and the results are shown in Table 8 below.

[0090]

[Table 8] As shown in Table 8, the main components BaO and Nd ₂ O ₃
When the composition of TiO ₂ and TiO ₂ is within the range of the present invention, the dielectric ceramic composition has low-temperature sinterability (the sintering density after firing at 920 ° C. is 5.0 g / cm ³ or more), and the obtained dielectric It was confirmed that the dielectric properties of the body porcelain were practically sufficient. As the proportion of Nd ₂ O ₃ decreases and the proportion of BaO increases, the permittivity ε tends to increase and Q tends to decrease. Further, it was observed that TCC tended to shift in the positive direction as the proportion of TiO ₂ increased.

On the other hand, when the content of BaO is less than 6 mol% (samples 72 and 73), the low-temperature sinterability cannot be ensured and the dielectric constant decreases. When the BaO content exceeds 23 mol% (samples 74 to 76), the Q characteristic deteriorates (100%).
(Less than 0).

When the content of Nd ₂ O ₃ is less than 13 mol% (samples 74 to 76), the Q characteristic deteriorates (less than 1000), and when the Nd ₂ O ₃ content exceeds 30 mol% ( In sample 72), it was confirmed that low-temperature sinterability could not be ensured.

Further, when the content of TiO ₂ is less than 64 mol% (samples 54, 55 and 74), the Q characteristic deteriorates (1).
When the TiO ₂ content exceeds 68 mol% (samples 51 and 52), it was confirmed that low-temperature sinterability could not be ensured.

As described above, the main components BaO and Nd
_By setting the composition of ₂ O ₃ and TiO ₂ within the range of the present invention, it is possible to select a wide dielectric constant of 40 to 80 or more while maintaining a small temperature coefficient, and maintain the predetermined dielectric constant. It has been clarified that a dielectric ceramic composition which can be sintered below the melting point of Ag can be obtained as it is.

[0095]

As described in detail above, according to the present invention, a Cu oxide, a Zn oxide, a B oxide, and an Ag oxide together with a BaO—Nd ₂ O ₃ —TiO ₂ main component having a predetermined composition range. As a result, a dielectric ceramic composition that can be sintered at a temperature equal to or lower than the melting point of Ag or an alloy containing Ag as a main component without lowering the dielectric properties can be obtained. As a result, it is possible to configure an electronic component using a metal having a low melting point, such as Ag or an Ag alloy, which has a low resistance, as an internal conductor. As a result, various characteristics of a high-frequency device can be improved, and miniaturization and cost reduction can be achieved. It becomes possible. Furthermore, since Ag contained as a sub-component suppresses Ag diffusion from the internal conductor into the dielectric, non-uniformity of the dielectric characteristics is prevented, and voids between the internal conductor and the dielectric are generated, and The occurrence of pull-in at the external connection portion of the conductor is prevented. Further, in the present invention, it is not necessary to contain a glass composition as an auxiliary component, so that deterioration of characteristics such as dielectric characteristics can be prevented, and a glass manufacturing process is not required. It is possible to remove the stability factor. In the present invention, P
Since it does not contain environmental contaminants such as bO and Bi ₂ O _3, it is possible to provide an electronic device adapted to recent environmental protection requirements, and special equipment such as waste liquid treatment in the manufacturing process. Is not required, so that the manufacturing cost can be reduced. Further, PbO and Bi ₂ O ₃ are substances that easily evaporate at a high temperature. Since the present invention does not contain these evaporable substances, instability during the manufacturing process can be removed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a chip capacitor;
(A) is a plan view, and (B) is a cross-sectional view taken along line II of the chip capacitor shown in (A).

FIG. 2 is a view showing a result of analyzing a concentration distribution of Ag in a dielectric body of a chip capacitor in Example 1.

FIG. 3 is a diagram showing an example of a sample for a continuity test;
(A) is a plan view, (B) is the sample shown in (A).
It is sectional drawing in the II-II line.

FIG. 4 is an enlarged cross-sectional view taken along line III-III of the sample shown in FIG.

[Explanation of symbols]

 1: Internal conductor 2: Dielectric 3: Terminal conductor

Continuation of the front page (56) References JP-A-10-330161 (JP, A) JP-A-9-188561 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35 / 42-35/49 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. The method according to claim 1, wherein the main component is a general formula xBaO.yNd ₂ O _3.
zTiO ₂ (provided that 6 ≦ x ≦ 23, 13 ≦ y ≦ 30,
64 ≦ z ≦ 68, x + y + z = 100)
And 0.1 to 3.0% by weight of Cu oxide in terms of CuO as a subcomponent with respect to the main component, and Zn oxide as Zn
O conversion by 0.1 to 4.0 wt%, 0.1 to 3.0 wt% of B oxide in terms _of B ₂ O _3, the Ag 0.3 to 1.5 wt%
A dielectric ceramic composition characterized by being contained in the range of: _2. After mixing the respective raw materials of BaO, Nd ₂ O ₃ and TiO ₂ , the mixture is calcined at a temperature of 1100 ° C. or more, and the general formula xBaO.yNd ₂ O ₃ .zTiO ₂ (where 6 ≦
x ≦ 23, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y +
z has a relationship of z = 100), and 0.1 to 3.0% by weight of Cu oxide in terms of CuO as a subcomponent with respect to the base material powder, Zn oxide 0.1 to 4.0% by weight in terms of ZnO, and B oxide as B ₂ O ₃
A powder obtained by mixing 0.1 to 3.0% by weight and Ag in a range of 0.3 to 1.5% by weight is calcined again at a temperature lower than the sintering temperature of the powder. Pulverizing the calcined powder to a predetermined particle size. 3. After mixing the respective raw materials of BaO, Nd ₂ O ₃ and TiO ₂ , they are calcined at a temperature of 1100 ° C. or more, and the general formula xBaO.yNd ₂ O ₃ .zTiO ₂ (where 6 ≦
x ≦ 23, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y +
z has a relationship of z = 100), and 0.1 to 3.0% by weight of Cu oxide in terms of CuO as a subcomponent with respect to the base material powder, Zn oxide 0.1 to 4.0% by weight in terms of ZnO, and B oxide as B ₂ O ₃
The powder mixed so as to be in the range of 0.1 to 3.0% by weight in terms of conversion is calcined again at a temperature lower than the sintering temperature of the powder, and Ag is further added to the calcined powder as an auxiliary component. And pulverizing the powder to a predetermined particle size after adding the powder to the material powder in a range of 0.3 to 1.5% by weight. 4. The additive form of the secondary component Ag is metal Ag powder,
The method for producing a dielectric ceramic composition according to claim 2 or 3, wherein the method is at least one of AgNO ₃ , Ag ₂ O, and AgCl. 5. The method for producing a dielectric ceramic composition according to claim 2, wherein the first calcination is performed at a predetermined temperature in the range of 1100 to 1350 ° C. .