JP2003206177A - Dielectric ceramic composition for high-frequency and dielectric resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dielectric ceramic composition for high-frequency which has a low dielectric constant, also has a high Q value in the measurement frequency of 10 GHz, and in which firing conditions can be improved, and to provide a dielectric resonator. <P>SOLUTION: The composition consists of a compound oxide consisting of Mg, Al and Si as metallic elements. Yb is incorporated by 0.1 to 15 wt.% expressed in terms of Yb<SB>2</SB>O<SB>3</SB>into the main components, when the compositional formula of molar ratios by the oxide of each metallic element is expressed as xMgO-yAl<SB>2</SB>O<SB>3</SB>-zSiO<SB>2</SB>, in which the (x), (y), and (z) satisfy 10≤x≤40, 10≤y≤40, 20≤z≤80, and x+y+z=100. Further, the composition has a dielectric constant of ≤6, and a Q value of ≥3,000 in the measurement frequency of 10 GHz. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency dielectric composition used in a high frequency range such as a microwave and a millimeter wave, for example, a microwave such as a microwave and a millimeter wave integrated circuit, and a millimeter wave. High frequency dielectric porcelain composition useful as a material for circuit element substrates, dielectric resonator supports, dielectric resonators, dielectric waveguides, dielectric antennas, etc. used in a band, and a dielectric porcelain support member The present invention relates to a dielectric resonator fixed to a substrate via.

[0002]

2. Description of the Related Art A high frequency circuit element such as a microwave or millimeter wave integrated circuit may employ a structure in which a dielectric resonant ceramic is fixed to a substrate via a supporting member. For example, as shown in FIG. 1, the dielectric resonator control type microwave oscillator mounts the dielectric porcelain 1 on the porcelain substrate 3 via the support member 2, and the electromagnetic field H leaking to the outside of the dielectric porcelain 1 is obtained.
Is used to connect to the strip line 4 provided on the porcelain substrate 3, and the metal case 5 accommodates these.

In this type of high frequency circuit, by controlling the leakage of the electric field of the dielectric porcelain 1 through the support member 2, a resonance system with a high unloaded Q is constructed, so that the support member is formed. 2 has a low relative permittivity and a dielectric loss (t
It is necessary to use a material having a small an δ) (having a large Q value). Therefore, conventionally, a supporting member material has a relative dielectric constant of about 7, and a Q value of about 1500 at a measurement frequency of 10 GHz.
0 forsterite is adopted, and the material of the porcelain substrate is mainly having a relative dielectric constant of about 10 and a measuring frequency of 10
Alumina porcelain having a Q value of 20,000 or more at GHz has been adopted (for example, refer to Patent Document 1).

On the other hand, as a material having a low relative dielectric constant, cordierite has been conventionally known, but since a firing temperature range is extremely narrow, it is difficult to obtain a dense sintered body, and a glass material is added. A glass ceramic having a relative dielectric constant of 4 to 6 and a Q value of about 1000 at a measurement frequency of 10 GHz is known (see, for example, Patent Document 2).

[0005]

[Patent Document 1] Japanese Patent Laid-Open No. 62-103904

[Patent Document 2] JP-A-61-234128

[0006]

However, the relative permittivities of conventionally used alumina and forsterite are about 10 and about 7, respectively, and with the recent widespread use of high frequency dielectric resonators. , Lower dielectric constant materials have been sought.

On the other hand, porcelain such as glass ceramics used as a low dielectric constant material has a small relative dielectric constant of about 4 to 6, but has a Q value of about 1000 at 10 GHz, which is a recent high frequency dielectric. Along with the widespread use of resonators, a low dielectric constant material having a higher Q value has been required.

Alumina porcelain, which is mainly used for the porcelain substrate of the resonator, has a relatively high relative dielectric constant of about 10, and the line width becomes too small when forming a high impedance strip line (usually (1 μm or less), there is a problem that disconnection occurs or relative line width variation increases, and the defect rate of the microwave integrated circuit increases.

On the other hand, the impedance of the strip line in this type of porcelain substrate is inversely proportional to the relative permittivity and the width of the strip line if the substrate thickness is constant. Therefore, instead of reducing the line width, Impedance can also be increased by using a substrate material having a low relative dielectric constant, and therefore, a lower dielectric constant material has been required.

As a means for solving the above problems, the present inventors have proposed a complex oxide composed of Mg, Al, and Si as metal elements, the molar ratio composition formula of which is xMgO-yAl ₂ When expressed as O ₃ -zSiO ₂ , x, y, and z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40, 20 ≦.
z ≦ 80, x + y + z = 100 are satisfied, and the relative dielectric constant is 6
Below, and the Q value at a measurement frequency of 10 GHz is 2000
The above high-frequency dielectric ceramic composition and dielectric resonator have already been proposed (Japanese Patent Application No. 7-195211).

This high frequency dielectric ceramic composition was excellent in that it had a lower dielectric constant than alumina and forsterite, and a higher Q value than glass ceramics. However, conventionally, since cordierite has a very narrow firing temperature range, it is difficult to obtain a dense sintered body, and the high frequency dielectric ceramic composition previously filed by the above inventors was no exception.

An object of the present invention is to provide a dielectric ceramic composition for high frequency and a dielectric resonator which have a low dielectric constant, a high Q value at a measurement frequency of 10 GHz, and can improve firing conditions. .

[0013]

The high frequency dielectric ceramic composition of the present invention is a composite oxide composed of Mg, Al and Si as metal elements, and the composition formula of the molar ratio by the oxide of each metal element is used. Is expressed as xMgO-yAl ₂ O ₃ -zSiO ₂ , the above x, y and z are 10 ≦ x ≦ 40 and 10 ≦ y ≦.
0.1% to 15% by weight of Yb in terms of Yb ₂ O ₃ in the main component satisfying 40, 20 ≦ z ≦ 80, and x + y + z = 100.
Including, relative dielectric constant of 6 or less, measurement frequency 10
The Q value at GHz is 3000 or more.

The dielectric resonator of the present invention is a dielectric resonator in which a dielectric ceramic is fixed on a substrate via a supporting member, wherein the substrate and / or the supporting member is the above-mentioned high frequency dielectric. It is composed of a porcelain composition.

[0015]

In the high frequency dielectric ceramic composition of the present invention,
Yb to Yb ₂O₃0.1-15 in conversion
Strict firing conditions such as firing temperature are required due to the inclusion of wt%.
Do not significantly deteriorate the characteristics obtained by tight control.
Therefore, the firing conditions can be improved. That is, the relative permittivity
4-6, Q value at measurement frequency 10 GHz is 3000 or more
The above characteristics can be obtained and, for example, the firing temperature
Increased the range from 10 ℃ to 100 ℃
Can be manufactured easily, and the productivity can be improved.
You can

Further, by using such a dielectric ceramic having a low dielectric constant and a high Q value for a supporting member and / or a substrate of a dielectric resonator, for example, a high-impedance microwave integrated circuit for microwaves or the like can be obtained. The circuit element for use can be manufactured without impairing reliability.

[0017]

DETAILED DESCRIPTION OF THE INVENTION high frequency dielectric ceramic composition of the present invention, the molar ratio xMgO-yAl ₂ O ₃ composition formula -zSi
When expressed as O ₂ , x, y, and z are 10 ≦ x ≦ 40, 1
The main component is one that satisfies 0 ≦ y ≦ 40, 20 ≦ z ≦ 80, and x + y + z = 100.

The main component composition of the high frequency porcelain composition of the present invention is limited to the above range for the following reason. That is, M
The reason that x, which represents the mole percentage of gO, is 10 to 40 mol% is that if it is less than 10 mol%, a good sintered body cannot be obtained and the Q value is low, and if it exceeds 40 mol%, the relative dielectric constant becomes high. Is. In particular, x, which indicates the amount of MgO, is preferably 15 to 35 mol% from the viewpoint of setting the Q value to 5000 or more.

Further, y representing the molar percentage of Al ₂ O ₃ is 1
The content of 0 to 40 mol% is set so that when the Al ₂ O ₃ amount y is smaller than 10 mol%, a good sintered body cannot be obtained, and Q
This is because the value becomes low, and when it exceeds 40 mol%, the relative dielectric constant becomes high. Y showing the amount of Al ₂ O ₃ has a Q value of 5000
From the viewpoint of the above, 17 to 35 mol% is desirable.

The molar percentage z of SiO ₂ is set to 20 to 80 mol%. The reason is that when z is less than 20 mol%, the relative dielectric constant becomes large, and when it exceeds 80 mol%, a good sintered body is obtained. It cannot be obtained and the Q value becomes low. Z, which indicates the amount of SiO _2, is Q
30-65 mol% from the point that the value is 5000 or more
Is desirable.

According to the present invention, Yb is added to the above main component.
Is contained in an amount of 0.1 to 15% by weight in terms of Yb ₂ O ₃ . Yb is contained in an amount of 0.1 to 15% by weight in terms of Yb ₂ O ₃ because the densification firing temperature does not become wide when the content of Yb is less than 0.1% by weight, and when it is more than 15% by weight. This is because the dielectric loss increases and the Q value decreases. Although the densification firing temperature becomes wider as the content of Yb increases, on the other hand, the relative dielectric constant increases and the Q value decreases, so that these characteristics and the densification firing temperature are taken into consideration. It is desirable to determine the content.

The high frequency dielectric porcelain composition of the present invention comprises Q
To set the value to 5000 or more, 15 ≦ x ≦ 35, 17
It is desirable to satisfy ≦ y ≦ 35 and 30 ≦ z ≦ 70. Further, in order to set the Q value to 7,000 or more, 20 ≦
It is desirable that x ≦ 30, 17 ≦ y ≦ 30, and 40 ≦ z ≦ 60 are satisfied. In the present invention, in particular, the composition of cordierite, ie x = 22.2, y = 22.2, z = 55.6.
Therefore, it is desirable to contain Yb in an amount of 0.1 to 10% by weight in terms of Yb ₂ O ₃ .

Q value at a measurement frequency of 10 GHz is 3000
The reason for satisfying the above is that when the Q value is 3,000 or more, it is possible to sufficiently cope with a recent high frequency band dielectric resonator. The higher the Q value, the more desirable, but especially the measurement frequency is 10 GHz.
It is desirable that the Q value at is 5000 or more.

In the dielectric ceramic composition of the present invention, the main crystal phase is cordierite, and other crystal phases are
Mullite, spinel, protoenstatite, clinoenstatite, cristobalite, forsterite,
Tridymite, safarin, Yb ₂ Si ₂ O _7, etc. may precipitate, but the precipitation phase differs depending on the composition.

Further, the dielectric resonator of the present invention, as shown in FIG. 1, has the dielectric ceramic 1 on the substrate 3 with the support member 2 interposed therebetween.
Are fixed, and the supporting member 2 or the substrate 3, or the supporting member 2 and the substrate 3 are made of the above dielectric ceramic composition. In this case, a well-known material is used as the dielectric ceramic 1. The dielectric ceramic composition of the present invention may be used as the dielectric ceramic 1.

In the high frequency dielectric ceramic composition of the present invention, for example, MgCO ₃ powder, Al ₂ O ₃ powder, SiO ₂ powder, Yb ₂ O ₃ powder is used as raw material powder, and weighed at a predetermined ratio, Wet mix and dry, and mix this mixture in air 1
It was calcined at 100 to 1300 ° C and then pulverized. It is obtained by adding an appropriate amount of a binder to the obtained powder and shaping the powder, and firing the shaped body in the atmosphere at 1300 to 1400 ° C.

Raw material powders composed of metallic elements of Mg, Al, Si and Yb may be inorganic compounds such as oxides, carbonates and acetates, or organic compounds such as organic metals. What is formed is as follows.

The high frequency dielectric ceramic composition of the present invention comprises Mg, Al, Si and Yb as metal elements. For example, impurities such as crushed balls and raw material powders such as Ca, Ba and Zr, Ni, Fe, Cr, P, N
A, Ti, etc. may be mixed in.

Further, in the high frequency dielectric ceramic composition of the present invention, if a low dielectric constant and a high Q value are required, for example, a circuit element substrate, a dielectric ceramic of a dielectric resonator, a dielectric Any material such as a waveguide or a dielectric antenna can be applied, but as described above, it is most suitable for the supporting member or the substrate of the dielectric resonator.

[0030]

EXAMPLES As raw material powders, MgCO _{3 having} a purity of 99%, Al ₂ O _{3 having} a purity of 99.7%, SiO ₂ powder having a purity of 99.4%, and Yb ₂ O ₃ having a purity of 99.9% were used. The sintered body was weighed so as to have the composition shown in Table 1, wet-mixed for 15 hours, and then dried.
After calcination for an hour, it was crushed. An appropriate amount of binder was added to the obtained powder to granulate it, which was molded under a pressure of 1000 kg / cm ² to obtain a molded body having a diameter of 12 mm and a thickness of 8 mm. This molded body was fired in the atmosphere at 1200 to 1550 ° C. for 2 hours to produce a porcelain, which was polished and the diameter was 10 mm.
A dielectric ceramic sample having a thickness of 6 mm was obtained.

Using these samples, the dielectric constant and the Q value at a frequency of 10 GHz were measured by the dielectric cylinder resonator method, and the results are shown in Table 1.

[0032]

[Table 1]

According to Table 1, the high frequency dielectric ceramic composition according to the present invention has a low relative permittivity of 6 or less and a high Q value of 3000 or more at a measurement frequency of 10 GHz. Recognize. Also, it is understood that the range of the firing temperature is expanded as the Yb content is increased.

Incidentally, in FIG. The X-ray-diffraction chart figure of 12 is shown. It can be seen from FIG. 2 that Yb ₂ Si ₂ O ₇ is precipitated in addition to cordierite.

[0035]

EFFECTS OF THE INVENTION The high frequency dielectric ceramic composition of the present invention has a low relative dielectric constant of 6 or less and a densification firing temperature in a state where the Q value at 10 GHz is maintained at a high Q value of 3000 or more. The range can be expanded and productivity can be improved. Then, for example, by using it as a support member or substrate of a dielectric resonator, a high-frequency circuit element such as a high-impedance microwave integrated circuit can be manufactured without impairing reliability. Further, since it has a low dielectric constant and a high Q value, for example, a circuit element substrate used in microwaves such as microwaves and millimeter wave integrated circuits and millimeter wave bands, a dielectric resonator support, a dielectric resonator, It is most suitable for materials such as dielectric waveguides and dielectric antennas.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a dielectric resonator control type microwave oscillator showing an example of a high frequency circuit element.

2 is a sample No. of Table 1. 12 is an X-ray diffraction diagram showing a crystal structure of 12.

[Explanation of symbols]

1. Dielectric porcelain 2 ... Support member 3 ... Porcelain substrate

Claims (2)

[Claims] 1. A composite oxide comprising Mg, Al and Si as metal elements, wherein the composition formula of the molar ratio of oxides of each metal element is represented by xMgO-yAl ₂ O ₃ -zSiO _2. x, y, and z are 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 In a main component satisfying x + y + z = 100, Yb is 0.1 to Yb ₂ O _{3 in} terms of Yb ₂ O _3.
A high-frequency dielectric ceramic composition containing 15% by weight, a relative dielectric constant of 6 or less, and a Q value of 3000 or more at a measurement frequency of 10 GHz. 2. A dielectric resonator in which a dielectric ceramic is fixed on a substrate via a supporting member, wherein the substrate and / or the supporting member are Mg, Al, Si as a metal element.
A composite oxide comprising, when the composition formula of the molar ratio of an oxide of each metal element expressed as _{xMgO-yAl 2 O 3 -zSiO 2} , wherein x, y, z is 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 In a main component satisfying x + y + z = 100, Yb is 0.1 to Yb ₂ O _{3 in} terms of Yb ₂ O _3.
A dielectric resonator containing 15% by weight, a relative dielectric constant of 6 or less, and a Q value of 3000 or more at a measurement frequency of 10 GHz.