JP3215004B2 - 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 porcelain composition applied to electronic circuit boards and electronic components used in a high frequency range.
This is a dielectric porcelain composition used for filters and 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 a conductor is simultaneously fired with an electronic circuit board or the like made of the dielectric ceramic, 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, the conventional electronic circuit board has a problem that the Q value of the resonance circuit and 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 filters by increasing the relative dielectric constant εr in a specific frequency range. By increasing the Q value of the body ceramic, the Q value of the resonance circuit and the filter can be increased and the loss can be reduced. Therefore, various composite dielectrics have been proposed.

Conventionally, for example, a dielectric porcelain composition disclosed in Japanese Patent Application Laid-Open No. 4-292460 comprises an anorthite (CaO.Al ₂ O ₃ .2SiO ₂ ) -calcium titanate glass and TiO _2. Since it could be fired at a low temperature, it could be fired simultaneously with a metal such as Ag or Cu as a conductor.

[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 was a limit to the miniaturization of circuit boards.

This dielectric ceramic composition has a frequency of 6 GHz.
Since the Q value was as low as about 330 at the measurement frequency, the Q value of the resonance circuit was low.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can be fired at a relatively low temperature of 900 to 1050 ° C. simultaneously with a conductive metal such as Ag or Cu. High and temperature coefficient of resonance frequency τf
It is an object of the present invention to provide a dielectric ceramic composition having characteristics such as relatively small size and realizing miniaturization and high performance of a high-frequency electronic circuit board.

[0010]

The dielectric ceramic composition of the present invention According to an aspect of the composition formula (1-x) MgTiO ₃ -xCaTiO
₃ (where x represents a weight ratio, and 0.01 ≦ x ≦ 0.
15 to 20 parts by weight of a boron-containing compound in terms of B ₂ O ₃ and 1 to 12 parts by weight of a sodium-containing compound in terms of Na ₂ CO _{3 based on} 100 parts by weight of the main component represented by 15). is there.

Here, the weight ratio x of CaTiO ₃ is set to 0.0
The condition of 1 ≦ x ≦ 0.15 is the weight ratio x of CaTiO _3.
Is less than 0.01, the temperature coefficient τf of the resonance frequency
Greatly shifts to the minus side, and the weight ratio x is 0.1.
This is because if it exceeds 15, the temperature coefficient τf of the resonance frequency greatly shifts to the plus side. Therefore, CaTiO ₃
Is specified to be 0.01 to 0.15, and particularly preferably 0.05 to 0.10 from the viewpoint of the temperature coefficient τf of the resonance frequency of the dielectric ceramic.

The dielectric porcelain composition of the present invention contains 10 main components.
Relative to 0 parts by weight, the boron-containing compound in terms _of B ₂ O ₃ 3
To 20 parts by weight and a sodium-containing compound in an amount of 1 to 12 parts by weight in terms of Na ₂ CO _3.
The addition of 3 to 20 parts by weight in terms of ₂ O ₃ means that when the boron-containing compound is less than 3 parts by weight, the dielectric ceramic composition does not become dense even at a firing temperature of 1100 ° C. If the thickness exceeds the part, the crystal phase of MgTiO ₃ —CaTiO ₃ changes and the porcelain characteristics deteriorate. Therefore, the addition amount of the boron-containing compound is specified to be 3 to 20 parts by weight with respect to 100 parts by weight of the main component, and it is particularly preferable to be 3 to 9 parts by weight from the viewpoint of the Q value of the dielectric ceramic. Examples of boron-containing compounds include metallic boron, B ₂ O ₃ , colemanite,
There is CaB ₂ O ₄ .

The reason why the sodium-containing compound is added in an amount of 1 to 12 parts by weight in terms of Na ₂ CO ₃ with respect to 100 parts by weight of the main component is that the sodium-containing compound is less than 1 part by weight in terms of Na ₂ CO _3. In this case, the firing temperature is 1100
If it does not densify even at ℃ and exceeds 12 parts by weight,
This is because the crystal phase of gTiO ₃ —CaTiO ₃ changes and the porcelain characteristics deteriorate. Therefore, the amount of the sodium-containing compound added is 100 parts by weight of the main component and Na ₂ CO 3.
_It is specified in terms of ₃ to 1 to 12 parts by weight, and particularly preferably 5 to 9 parts by weight from the viewpoint of the Q value of the dielectric porcelain.

In the present invention, oxides such as Si, Zn, Mn, Li, and K may be added as long as they do not adversely affect the dielectric properties. Become. In the dielectric porcelain composition of the present invention, in particular,
The composition formula is (1-x) MgTiO ₃ xCaTiO ₃ (where x represents a weight ratio, and 0.05 ≦ x ≦ 0.10)
The boron-containing compound is added in an amount of ₃ to 9 parts by weight in terms of B ₂ O ₃ and the sodium-containing compound in an amount of 5 to 9 parts by weight in terms of Na ₂ CO ₃ with respect to 100 parts by weight of the main component represented by desirable.

In the present invention, the boron-containing compound and the sodium-containing compound are composed of the main constituent elements Mg, Ti,
Reacts with part of Ca to form a glass phase, (Mg, Ca)
At the grain boundaries between TiO ₃ particles or (Mg, Ca) T
The particles exist at the grain boundaries between the iO ₃ particles, the MgTiO ₃ particles, and the CaTiO ₃ particles.

The dielectric porcelain composition of the present invention is, for example,
Each raw material powder of gTiO ₃ and CaTiO ₃ is weighed so as to have a predetermined amount, mixed and pulverized.
Calcinate at a temperature of ° C. for 1 to 3 hours. By this calcination (M
g, Ca) TiO ₃ is produced. The boron-containing compound powder and the sodium-containing compound powder are weighed to a predetermined amount in the obtained calcined material, mixed and pulverized, molded by press molding or the like, and then subjected to a binder removal treatment in the air. Alternatively, it is obtained by baking in a nitrogen atmosphere at 900 to 1050 ° C. for 0.5 to 2.0 hours.

[0017]

The dielectric porcelain composition of the present invention has a composition of 900 to 105.
Since it can be fired at a relatively low temperature of 0 ° C., it can be fired at the same time as a conductive metal such as Ag or Cu. Because it can be smaller,
The miniaturization and high performance of the high-frequency electronic circuit board can be realized.

[0018]

EXAMPLES Hereinafter, the dielectric ceramic composition of the present invention will be described in detail based on examples. First, Mg of purity 99% or more
The raw material powders of TiO ₃ and CaTiO ₃ are weighed so as to have a weight ratio shown in Table 1, water is added as a medium to the raw material powder and mixed for 24 hours in a ball mill, and then the mixture is dried. The dried product was calcined at a temperature of 1200 ° C. for 1 hour.

B ₂ O ₃ powder and Na ₂ C
The O ₃ powder was weighed so as to have the ratio shown in Table 1, mixed in a ball mill for 24 hours, added with 1% by weight of polyvinyl alcohol as a binder, and then granulated, and the granulated material was about 1 t / cm. Press forming with a pressing force of ² and a diameter of about 12
mm, and a columnar molded body having a height of 10 mm was obtained.

[0020]

[Table 1]

Thereafter, the molded body was heated at 400 ° C. for 4 hours in the air to remove the binder, and subsequently fired in the air at each temperature shown in Table 1 for 60 minutes.

Both end surfaces of the thus obtained cylindrical body were polished to obtain a dielectric property evaluation sample.

The dielectric characteristics were evaluated by using the above-mentioned sample for evaluation by a dielectric columnar resonator method at a resonance frequency of 8 GHz.
And the relative permittivity εr of each sample and 1 at 8 GHz.
/ Tan δ, that is, the Q value is measured, and -40 to +
The temperature coefficient τf of the resonance frequency in the temperature range of 85 ° C. was measured. The results are shown in Table 1.

According to Table 1, the dielectric ceramic composition of the present invention can be fired at a relatively low temperature of 900 to 1050 ° C., has a relative dielectric constant εr of 19 or more, a Q value of 1500 or more,
Further, it can be seen that the temperature coefficient τf of the resonance frequency has excellent characteristics within ± 30.

[0025]

In the dielectric ceramic composition of the present invention, composition formula _{(1-x) MgTiO 3 -xCaTiO} 3 ( however, where x represents the weight ratio, 0.01 ≦ x ≦ 0.15) To 100 parts by weight of the main component represented by
_{Since 3} to 20 parts by weight in terms of ₂ O ₃ and 1 to 12 parts by weight of a sodium-containing compound in terms of Na ₂ CO ₃ were added,
Since it can be fired at a relatively low temperature of 0 to 1050 ° C., it can be fired simultaneously with a conductive metal such as Ag or Cu, has a high relative dielectric constant in a high frequency region, has a high Q value, and has a resonance frequency. The temperature characteristics of the high-frequency electronic circuit board can be further reduced and the performance thereof can be improved.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nobuyoshi Fujikawa 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Examiner at Kyocera Research Institute Tatsuo Takeshige (56) References JP-A-51-30958 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/42-35/49 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] A composition formula (1-x) MgTiO ₃ -xCa
TiO ₃ (where x represents a weight ratio and 0.01 ≦ x
≦ 0.15) based on 100 parts by weight of the main component
3-20 parts by weight of a boron-containing compound in terms _of B ₂ O _3, sodium-containing compound a dielectric ceramic composition characterized by containing added 1-12 parts by weight Na ₂ CO ₃ terms.