JP3085635B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition used for an electronic circuit board or an electronic component used in a high-frequency range.
The present invention relates to a dielectric porcelain composition most suitable for a filter or the like.

[0002]

2. Description of the Related Art Conventionally, various dielectric ceramics have been widely used as dielectric materials for electronic circuit boards and electronic components. In recent years, with the development and spread of high-frequency equipment such as mobile communication represented by mobile phones. Accordingly, dielectric ceramics have been actively used as electronic circuit boards and electronic components used in a high frequency range.

[0003] When simultaneously sintering an electronic circuit board or the like made of the dielectric ceramic and the conductor, the conductor is printed on the substrate so that the conductor is not melted at the firing temperature of the dielectric ceramic. It has a melting point higher than the firing temperature of dielectric ceramics such as alumina, steatite, and forsterite, for example, Pt, Pd, W,
Metals such as Mo have been used.

However, since the metal has a large conduction resistance, a conventional electronic circuit board requires a resonance circuit or an LC.
There has been a problem that the Q value of the filter becomes small and the transmission loss of the conductor line becomes large.

In order to solve such a problem, various dielectric ceramics have been proposed which employ a metal such as Ag or Cu having a small conduction resistance as a conductor and can be co-fired at a low temperature. Furthermore, in order to respond to recent demands for miniaturization and high performance of high-frequency electronic circuit boards, it is possible to reduce the size of resonance circuits and LC filters by increasing the relative permittivity εr in a specific frequency range. By increasing the Q value of the dielectric ceramic, the Q value of the resonance circuit or the LC filter can be increased and the loss can be reduced, and thus various composite dielectrics have been proposed.

As such a dielectric porcelain composition, a composition disclosed in, for example, Japanese Patent Application Laid-Open No. 4-292460 has been known.
A glass titanate-based glass and TiO ₂ are disclosed and can be fired at a low temperature.
It can be co-fired with a metal such as u.

[0007]

However, in the dielectric ceramic composition disclosed in Japanese Patent Application Laid-Open No. 4-292460, the relative dielectric constant εr is as low as less than 16 in a high frequency region of 4 to 6 GHz, and the relative dielectric constant εr is low. There has been a limit to miniaturization and high performance of circuit boards. Further, the dielectric ceramic composition had a low Q value of about 330 at the maximum at the measurement frequency of 6 GHz, so that the Q value of the resonance circuit was low.

[0008] The present invention has been made in view of the above problems,
It can be fired at a relatively low temperature of 850 to 950 ° C. simultaneously with a conductive metal such as Ag or Cu, and has a relative dielectric constant ε of the dielectric ceramics.
The object is to provide a dielectric ceramic composition having characteristics such as high r and Q values, and a relatively small temperature coefficient τf of the resonance frequency, which can realize miniaturization and high performance of a high-frequency electronic circuit board and the like. Is what you do.

[0009]

The dielectric porcelain composition of the present invention is a composite oxide containing at least Ba, Mg, W and Ta as a metal component, and has a composition formula based on a molar ratio of aBaO.bMgO. When expressed as cWO ₃ .dTaO _5/2 , a, b, c and d are 0.40 ≦ a ≦ 0.5
5, 0.10 ≦ b ≦ 0.40, 0 ≦ c ≦ 0.30, 0 ≦
d ≦ 0.40, 0.20 ≦ c + d ≦ 0.40, a + b +
4. More than 0.2 parts by weight of boric acid compound in terms of B ₂ O ₃ with respect to 100 parts by weight of the main component satisfying c + d = 1.
0 to not more than 1.0 part by weight of an alkali metal-containing compound in terms of carbonate is added.

Here, the molar ratio a of BaO in the main component a
Is set to 0.40 ≦ a ≦ 0.55 because when the molar ratio of BaO is less than 0.40, the Q value decreases and sintering becomes difficult, and when a exceeds 0.55, Q This is because the value decreases. It is particularly desirable that the molar ratio a of BaO be 0.46 ≦ a ≦ 0.54.

Further, the molar ratio b of MgO is 0.10 ≦ b ≦
The reason for setting the ratio to 0.40 is that when the molar ratio of MgO is less than 0.10, sintering becomes difficult or the Q value is reduced, and when the molar ratio b exceeds 0.40, the Q value becomes lower. This is because the temperature decreases and the sintered body becomes difficult. MgO molar ratio b
Is particularly preferably 0.13 ≦ b ≦ 0.25.

Further, when the molar ratio c of WO ₃ is 0 ≦ c ≦ 0.
The reason for setting the value to 30 is that when the molar ratio of WO ₃ exceeds 0.30, the Q value decreases. It is particularly desirable that the molar ratio c of WO ₃ is 0 <c ≦ 0.15.

Further, the molar ratio d of TaO _5/2 is defined as 0 ≦ d ≦
The reason for setting the ratio to 0.40 is that when the TaO _5/2 molar ratio is larger than 0.40, the Q value decreases. TaO _5/2
Is particularly desirable to satisfy 0.15 ≦ d <0.40.

Furthermore, the reason _why the total amount of the molar ratio c of WO _{3 and} the molar ratio d of TaO _5/2 is 0.20 ≦ c + d ≦ 0.40 is that c + d is smaller than 0.20 or conversely. If c + d is larger than 0.40, the Q value will decrease or sintering will fail. WO ₃ molar ratio c and TaO
It is desirable that the total amount of the molar ratio d of _{5/2 be} 0.24 ≦ c + d ≦ 0.40.

The dielectric porcelain composition according to the present invention is characterized in that, based on 100 parts by weight of the main component, the boric acid compound is more than 0.2 parts by weight and not more than 5.0 parts by weight in terms of B ₂ O ₃ , Is added in an amount of 1.0 to 9.0 parts by weight in terms of carbonate.

The reason that the boric acid compound is added in an amount of more than 0.2 part by weight and not more than 5.0 parts by weight in terms of B ₂ O ₃ with respect to 100 parts by weight of the main component is that the amount of the boric acid compound is 0.1 part by weight in terms of B ₂ O ₃ . If it is less than 2 parts by weight, sintering becomes difficult at 950 ° C. or less,
This is because simultaneous sintering with Ag or the like cannot be performed, and conversely, if the amount is more than 5 parts by weight, the Q value becomes small.

It is particularly desirable to add the boric acid compound in an amount of 0.3 to ₃ parts by weight in terms of B ₂ O ₃ . Examples of boric acid compounds include B ₂ O ₃ , colemanite, CaB ₂ O ₄ , and ZnB ₂
O ₄ there is.

The reason why the alkali metal-containing compound is added in an amount of 1.0 to 9.0 parts by weight in terms of carbonate with respect to 100 parts by weight of the main component is that the alkali metal-containing compound is added in an amount of 1.0% in terms of carbonate.
When the amount is less than 0 parts by weight, sintering at 950 ° C. or less becomes difficult, and simultaneous sintering with Ag or the like cannot be performed. Conversely, when the amount is more than 9 parts by weight, the Q value becomes small. is there. For example, when the alkali metal is Li, L
1.0 to 9.0 parts by weight in terms of i ₂ CO ₃ , 1.0 to 9.0 parts by weight in terms of K ₂ CO ₃ when the alkali metal is K, and Na ₂ when the alkali metal is Na 1.0 to 9.0 parts by weight in terms of CO _{3 is} added. It is desirable to add 1 to 7 parts by weight of the alkali metal compound in terms of oxide. Examples of the alkali metal include Li, Na, K, Rb, and Cs.

The dielectric porcelain composition of the present invention satisfies the above-mentioned composition and satisfies 0.17 ≦ 5 | a−0.5.
| + B + 0.2c <0.94 is preferably satisfied. This is because within this range, the Q value is higher and the characteristics of the circuit can be further improved.

Further, in the dielectric porcelain composition of the present invention,
ABaO · bMgO · cWO the formula by molar ratio _{of 3-}
When expressed as dTaO _5/2 , 0.46 ≦ a ≦ 0.54,
0.13 ≦ b ≦ 0.25, 0 <c ≦ 0.15, 0.15
≦ d <0.40, 0.24 ≦ c + d ≦ 0.40, a + b
With respect to 100 parts by weight of the main component satisfying + c + d = 1,
0.3 to 3 parts by weight of boric acid compound terms _of B ₂ O _3, it is desirable that the alkali metal-containing compound is added 1-7 parts by weight with carbonate terms.

In the present invention, the boric acid compound and the alkali metal-containing compound are composed of Ba, Mg,
Reacts with a part of W and Ta to form a glass phase, and at a grain boundary between BaO particles, MgO particles, WO ₃ particles, and TaO _5/2 particles, or at a grain boundary between these particles and Ba, Mg, W, Ta. Are present at the grain boundaries between the solid solution particles that have mutually dissolved.

The dielectric porcelain composition of the present invention comprises, for example, B
ACO _3, each raw material powder of _{MgCO 3, WO 3, Ta 2} O 5 were weighed to make a predetermined amount, were mixed and pulverized, which 1
Calcination is performed at a temperature of 200 to 1400 ° C for 1 to 3 hours. In the obtained calcined product, for example, a boric acid compound such as B ₂ O ₃ and an alkali metal-containing compound powder such as Li ₂ CO ₃ are weighed so as to have a predetermined amount, mixed, pulverized, and press-formed. And then debindered in air, and then 850 in air or nitrogen atmosphere.
It is obtained by baking at 950C for 0.5-2.0 hours.

[0023]

According to the dielectric porcelain composition of the present invention, 850 to 95
It can be fired at a relatively low temperature of 0 ° C. at the same time as a conductive metal such as Ag or Cu, the dielectric constant εr and Q value of the dielectric ceramics are high, and the temperature coefficient τf of the resonance frequency can be relatively small. The size and performance of the electronic circuit board and the like can be reduced.

[0024]

EXAMPLES Hereinafter, the dielectric ceramic composition of the present invention will be described in detail based on examples.

First, BaCO ₃ , Mg having a purity of 99% or more
After weighing each raw material powder of CO ₃ , WO ₃ , and Ta ₂ O ₅ so as to have a molar ratio shown in Tables 1 and 2, water was added to the raw material powder and mixed for 24 hours in a ball mill. The mixture was dried and then calcined at a temperature of 1400 ° C. for 1 hour.

The obtained calcined product was weighed with B ₂ O ₃ powder and an alkali metal-containing compound in the proportions shown in Tables 1 and 2 and mixed in a ball mill for 24 hours. The granulated product was press-formed with a pressing force of about 1 t / cm ² to obtain a cylindrical shaped body having a diameter of about 20 mm and a height of 10 mm.

[0027]

[Table 1]

[0028]

[Table 2]

Thereafter, the compact is placed in air at 40
The binder was removed by heating at a temperature of 0 ° C. for 4 hours, followed by baking at 950 ° C. for 30 minutes. Both end surfaces of the thus obtained cylindrical body were polished flat to prepare a sample for dielectric property evaluation.

The dielectric properties were evaluated by setting the resonance frequency of each sample to 6 to 8 GHz by the dielectric cylinder resonator method using the samples, and the relative permittivity εr of each sample and 1/7 at 7 GHz.
tanδ, that is, the Q value was measured, and -40 to +8
The temperature coefficient τf of the resonance frequency in the temperature range of 5 ° C. was measured. Tables 3 and 4 show these results.

[0031]

[Table 3]

[0032]

[Table 4]

According to Tables 3 and 4, the dielectric ceramic composition of the present invention can be fired at a relatively low temperature of 950 ° C. or less, and has a relative dielectric constant εr of 12 or more and a Q value of 5 or more.
It can be seen that it has excellent characteristics of not less than 00 and a temperature coefficient τf of the resonance frequency within ± 30.

[0034]

According to the dielectric ceramic composition of the present invention, 950 is obtained.
It can be fired simultaneously with conductive metals such as Ag and Cu at a relatively low temperature of ℃ or lower, has a high relative dielectric constant in the high frequency region, has a high Q value, and has excellent temperature characteristics of resonance frequency, and has a high frequency electronic circuit board, etc. It is possible to realize further miniaturization and higher performance.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Nobuyoshi Fujikawa 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Examiner at Kyocera Research Institute Yuichi Fukakusa (56) References JP-A-6-187828 (JP, A) JP-A-5-85804 (JP, A) JP-A-2-18806 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/495

Claims (1)

(57) [Claims] 1. A metal component comprising at least Ba, Mg, W
And made from a composite oxide containing Ta, when the composition formula by molar ratio, expressed as _{aBaO · bMgO · cWO 3 · dTaO} 5/2, a, b, c and d are 0.40 ≦ a ≦ 0.55 0.10 ≦ b ≦ 0.40 0 ≦ c ≦ 0.30 0 ≦ d ≦ 0.40 0.20 ≦ c + d ≦ 0.40 a + b + c + d = 1 More than 0.2 parts by weight and not more than 5.0 parts by weight in terms of B ₂ O ₃ , and an alkali metal-containing compound in an amount of 1.0 to 1.0 parts by weight in terms of carbonate.
A dielectric porcelain composition characterized by being added in an amount of 9.0 parts by weight.