JP3398281B2 - High frequency dielectric ceramic composition and dielectric resonator - Google Patents

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 high frequencies such as microwaves and millimeter waves. For example, circuit element substrates and dielectrics used in microwave and millimeter wave integrated circuits. High frequency dielectric ceramic composition useful as a material for a body resonator support, a dielectric resonator, a dielectric waveguide, a dielectric antenna, etc., and a dielectric resonance in which a dielectric ceramic is fixed to a substrate via a supporting member. It is related to vessels.

[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 ceramic 1 on the ceramic substrate 3 via the support member 2 to prevent the magnetic field H leaking to the outside of the dielectric ceramic 1. It has a structure in which it is connected to a strip line 4 provided on a porcelain substrate 3 and is housed in a metal case 5.

In this type of high frequency circuit, by controlling the leakage of the electromagnetic field of the dielectric porcelain 1 through the support member 2, a resonance system with a high no-load Q is constructed, so that it is supported. It is necessary to use a material having a low relative permittivity and a low dielectric loss (tan δ) (high Q value) for the member 2. Therefore, conventionally, forsterite having a relative permittivity of about 7 and a Q value of about 15,000 at a measurement frequency of 10 GHz has been conventionally used as the material of the supporting member 2, and the relative permittivity of the porcelain substrate is mainly about. 10. Alumina porcelain having a Q value of 20,000 or more at a measurement frequency of 10 GHz was adopted (for example, Japanese Patent Laid-Open No. 62-10390).
No. 4, etc.).

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. The relative permittivity obtained by
6. A glass ceramic having a Q value of about 1000 at a measurement frequency of 10 GHz is known (for example, Japanese Patent Laid-Open No. 61-
234128, etc.).

[0005]

However, with the conventionally used alumina and forsterite, the Q value at a measurement frequency of 10 GHz is 20000 or more, 1500 or more.
Although the relative permittivity is 0, the relative permittivity is about 10 and about 7, respectively. With the widespread use of dielectric resonators in high frequency bands in recent years, materials having lower relative permittivity have been required.

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. 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 permittivity of about 10, and the line width becomes too small when forming a high impedance stripline (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 thickness of the substrate is constant. In addition, by using a substrate material having a low relative dielectric constant,
The dance can be enhanced, and there is a need for lower dielectric constant materials.

As a means for solving the above problems, the present applicant has proposed a complex oxide composed of Mg, Al, and Si as metal elements, the molar ratio composition formula of which is an oxide of each metal element is xMgO.yAl ₂ O. _When expressed as 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).

The high frequency dielectric ceramic composition is alumina,
It was excellent in that it had a lower dielectric constant than 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 dielectric ceramic composition for high frequency applied by the above-mentioned inventor 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 has a molar ratio composition formula of oxides of the respective metal elements. When expressed as xMgO · yAl ₂ O ₃ · zSiO ₂ , the above x, y and z are 10 ≦ x ≦ 40 and 10 ≦ y ≦ 4.
0,20 ≦ z ≦ 80, x + y + z = 100 with respect to 100 parts by weight of the main component which satisfies, 0 Sc in Sc ₂ O ₃ conversion.
1 to 15 parts by weight is added and contained. Also,
When Mg, Al, Si, Zr, and unavoidable impurities as metal elements are used and the molar ratio composition formula of the oxide of the metal element is expressed as xMgO.yAl ₂ O ₃ .zSiO ₂ .
Where x, y and z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40,
With respect to 100 parts by weight of the main component satisfying 20 ≦ z ≦ 80 and x + y + z = 100, Zr is 0.1 to 100 in terms of ZrO _2.
In addition to containing 15 parts by weight of cordierite as a main crystal (excluding glass ceramics), the relative dielectric constant is 4
˜6, the Q value at a measurement frequency of 10 GHz is 2000 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 ceramic composition. It is configured by.

[0014]

In the dielectric ceramic composition of the present invention, 0.1 to 15 parts by weight of Zr or Sc in terms of ZrO ₂ or Sc ₂ O _{3 is} added to 100 parts by weight of the above-mentioned main component. The firing conditions can be improved without significantly deteriorating the characteristics obtained by strictly controlling the firing conditions such as the firing temperature. That is, the relative permittivity is 4 to 6, and the measurement frequency is 1
A dielectric porcelain having a low dielectric constant and a high Q value with a Q value at 0 GHz of 2000 or more can be obtained, and for example, a firing temperature range of about 10 ° C. can be expanded to about 50 ° C. Can be facilitated and mass productivity can be improved.

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 or the like can be obtained. The high frequency circuit element can be manufactured without impairing reliability.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The high frequency porcelain composition of the present invention comprises:
The composition formula of the molar ratio is xMgO · yAl ₂ O ₃ · zSiO ₂
And x, y, z are 10 ≦ x ≦ 40, 10 ≦
The main components are those satisfying 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, x, which represents the mole percentage of MgO, is set to 10 to 40 mol% because when it is less than 10 mol%, a good sintered body cannot be obtained.
This is because the value is low, and when it exceeds 40 mol%, the relative dielectric constant increases. In particular, x showing the amount of MgO has a Q value of 500.
From the viewpoint of being 0 or more, 15 to 35 mol% is desirable.

Further, y, which represents the molar percentage of Al ₂ O ₃ , is set to 10 to 40 mol%, so that when the amount y of Al ₂ O ₃ is smaller than 10 mol%, a good sintered body can be obtained. This is because the Q value becomes low and the relative dielectric constant becomes high when it exceeds 40 mol%. Y showing the amount of Al ₂ O ₃ has a Q value of 5
From the viewpoint of being 000 or more, 17 to 35 mol% is desirable.

The molar percentage z of SiO ₂ is 20 ≦ z ≦ 80.
The mol ratio is set so that when z is less than 20 mol%, the relative dielectric constant becomes large, and when it exceeds 80 mol%, a good sintered body cannot be obtained and the Q value becomes low. Z showing the amount of SiO ₂
Is preferably 30 to 65 mol% from the viewpoint that the Q value is 5000 or more.

According to the present invention, Zr is added in an amount of 0.1 to 15 parts by weight in terms of ZrO ₂ , or Sc is added in an amount of 0.1 to 15 parts by weight in terms of Sc ₂ O ₃ with respect to 100 parts by weight of the main component. However, when the Zr or Sc content is less than 0.1 parts by weight in terms of the above oxide, the densification firing temperature does not increase, and when it is more than 15 parts by weight, the dielectric loss is large. This is because the Q value becomes low. Zr
Alternatively, as the content of Sc is increased, the densification firing temperature becomes wider, but on the other hand, the relative dielectric constant increases and the Q value decreases. Alternatively, it is desirable to determine the content of Sc.

The high frequency dielectric ceramic composition of the present invention is Z
When r and Sc are contained, in order to set the Q value to 5000 or more, 15 ≦ x ≦ 35, 17 ≦ y ≦ 35, 3
It is desirable to satisfy 0 ≦ z ≦ 65. When Zr is contained, 20 ≦ x ≦ 30, 17 ≦ y ≦ 30, 40 ≦ z ≦ 6 in order to set the Q value to 7,000 or more.
It is desirable to satisfy 0. In the present invention, in particular,
The composition of gellite, that is, x = 22.2, y = 22.2,
For 100 parts by weight of the main component of z = 55.6, Zr
0.1 to 10 parts by weight in terms of ZrO ₂ , or Sc to S
It is desirable to contain 0.1 to 10 parts by weight in terms of c ₂ O ₃ .

The high frequency dielectric porcelain composition of the present invention has a Q value of 2000 or more at a measurement frequency of 10 GHz, which means that when the Q value is 2000 or more, the dielectric constant in the high frequency band in recent years is high. This is because it can be sufficiently applied to a body resonator. The higher the Q value is, the more preferable it is. However, in particular, the Q value at a measurement frequency of 10 GHz is 5000.
The above is desirable.

In the dielectric porcelain composition of the present invention, the main crystal phase is cordierite, and the other crystal phases are
Mullite, spinel, protoenstatite, clinoenstatite, cristobalite, forsterite,
ZrSiO ₄ when containing tridymite, safaline, and Zr, Sc ₂ Si when containing Sc
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.

The dielectric porcelain of the present invention, as a raw material powder,
For example, MgCO ₃ powder, Al ₂ O ₃ powder, SiO ₂ powder, ZrO ₂ or Sc ₂ O ₃ powder is used, weighed at a predetermined ratio, wet-mixed and dried, and this mixture is dried in the atmosphere at 1100-1300. After calcination at ℃, it was crushed. The obtained powder is molded by adding an appropriate amount of binder, and the molded body is heated at 1270 to 1445 ° C. for 5 minutes to 1 in an oxidizing atmosphere such as air or a non-oxidizing atmosphere such as Ar or N _2.
It is obtained by firing for 0 hours.

The dielectric ceramic composition of the present invention comprises Mg, Al, Si, Zr or Sc as a metal element. For example, Ca, Ba, Ni as impurities in pulverized balls or raw material powders. , Fe, Cr, P, Na, Ti
Etc. may be mixed.

In the 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 resonator dielectric ceramic, or a dielectric waveguide. , A dielectric antenna, etc. can be applied, but as described above, it is most suitable for a supporting member or a substrate of a dielectric resonator.

[0028]

【Example】

Example 1 MgCO _{3 having} a purity of 99% as a raw material powder, a purity of 99.7
% Al ₂ O ₃ , 99.4% pure SiO ₂ powder, and 99.9% pure ZrO ₂ were prepared. First, MgCO ₃ , A
L ₂ O ₃ and SiO ₂ powder were weighed so that the main component composition was as shown in Table 1, and thereafter, ZrO ₂ was added in an amount shown in Table 1 to 100 parts by weight of the main component. , This mixed powder is subjected to a ball mill using ZrO ₂ balls,
After wet-mixing for 15 hours, the mixture was dried, and the mixture was calcined in the air at 1200 ° C. for 2 hours and then pulverized. Add an appropriate amount of binder to the obtained powder and granulate.
Diameter 12 by press molding under a pressure of 00 kg / cm ^2.
A molded product having a thickness of 8 mm was obtained. This molded body in the atmosphere 1
Firing was performed at 250 to 1550 ° C. for 2 hours to obtain a dielectric ceramic sample having a diameter of 10 mm and a thickness of 6 mm.

Using this sample, 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.

[0030]

[Table 1]

According to Table 1, the high frequency dielectric ceramic composition according to the present invention has a low relative permittivity of 5.8 or less and a high Q value of 2830 or more at a measurement frequency of 10 GHz. I understand.

Incidentally, FIG. 2 shows an X-ray diffraction chart of the sample No.12. From FIG. 2, in addition to the cordierite,
It can be seen that spinel and ZrSiO ₄ are precipitated.

Example 2 MgCO _{3 having} a purity of 99% as a raw material powder, a purity of 99.7
% Al ₂ O ₃ , 99.4% pure SiO ₂ powder, and 99.9% pure Sc ₂ O ₃ were prepared. First, MgCO ₃ ,
Al ₂ O ₃ and SiO ₂ powder were used and weighed so that the main component composition became the composition shown in Table 2, and then, with respect to 100 parts by weight of the main component, only Sc ₂ O ₃ was added in the amount shown in Table 2. Add
This mixed powder was wet-mixed for 15 hours by a ball mill using ZrO ₂ balls and then dried, and this mixture was calcined in the air at 1200 ° C. for 2 hours and then pulverized.
An appropriate amount of binder was added to the obtained powder to granulate, and this was press-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 is fired in the atmosphere at 1200 to 1550 ° C. for 2 hours to have a diameter of 10 m.
A dielectric ceramic sample having a thickness of 6 mm was obtained.

Using this sample, 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 2.

[0035]

[Table 2]

According to Table 2, the high frequency dielectric ceramic composition according to the present invention has a low relative permittivity of 5.9 or less and a high Q value of 2620 or more at a measurement frequency of 10 GHz. I understand.

An X-ray diffraction chart of Sample No. 39 is shown in FIG. From FIG. 3, in addition to the cordierite,
It can be seen that spinel and Sc ₂ Si ₂ O ₇ are precipitated.

[0038]

INDUSTRIAL APPLICABILITY With the high frequency dielectric ceramic composition of the present invention, a ceramic having a low relative permittivity of 6 or less and a high Q value of 2000 or more at 10 GHz can be obtained. By using it as a support member or a substrate of a body resonator, it is possible to improve characteristics and manufacture a high-impedance circuit element for high frequencies such as a microwave integrated circuit without impairing reliability. Further, because of its low dielectric constant and high Q value, for example, circuit element substrates used in microwave and millimeter wave bands such as microwave and millimeter wave integrated circuits, dielectric resonator support bases, dielectric resonators, It is optimal as a material for 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. 1 of Example 1. X showing the crystal structure of 12
It is a line diffraction diagram.

3 is a sample No. 3 of Example 2. FIG. X showing the crystal structure of 39
It is a line diffraction diagram.

[Explanation of symbols]

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

Continuation of front page (56) Reference JP-A-4-338163 (JP, A) US Patent 3940255 (US, A) US Patent 3205079 (US, A) Byung C. Lim, Journal of the American Ceramic Society, 1993, vol. 76, No. 6, p. 1482-1490 Electronic Components Handbook, Jiji Shokan Co., Ltd., November 25, 1968, p. 154-157 Fine Ceramics Encyclopedia, Gihodo Publishing Co., Ltd., April 30, 1987, p. 194-195 (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 35/16-35/22

Claims (4)

(57) [Claims] 1. A composite oxide composed of Mg, Al and Si as metal elements, wherein when the molar ratio composition formula of the oxide of each metal element is represented by xMgO.yAl ₂ O ₃ .zSiO ₂ , , Y, and z are 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100 With respect to 100 parts by weight of the main component, Sc is Sc ₂
A high-frequency dielectric ceramic composition containing 0.1 to 15 parts by weight in terms of O ₃ . 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.
When the molar ratio compositional formula of the oxide of each metal element is represented by xMgO · yAl ₂ O ₃ · zSiO ₂ , x, y and z are 10 ≦ x ≦ 40 10 ≦ y Sc to Sc ₂ with respect to 100 parts by weight of the main component satisfying ≦ 40 20 ≦ z ≦ 80 x + y + z = 100.
A dielectric resonator containing 0.1 to 15 parts by weight in terms of O ₃ . 3. Mg, Al, Si as metal elements,
Zr and unavoidable impurities, and the molar ratio composition formula of the oxide of the metal element is xMgO.yAl ₂ O ₃ .zSiO ₂
Zr is expressed as ZrO with respect to 100 parts by weight of the main component satisfying the above-mentioned x, y and z of 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100.
0.1 to 15 parts by weight in terms of _{2 is} added and contained, and cordierite is the main crystal (glass ceramics are excluded).
Q ), relative permittivity of 4 to 6, Q at measurement frequency of 10 GHz
A high-frequency dielectric ceramic composition having a value of 2000 or more. 4. A dielectric resonator in which a dielectric ceramic is fixed on a substrate via a support member, wherein the substrate and / or the support member contain Mg and Al as metal elements,
It consists of Si, Zr, and unavoidable impurities, and the molar ratio compositional formula of the oxide of the metal element is xMgO · yAl ₂ O ₃ · z.
When expressed as SiO ₂ , Zr is represented by ZrO with respect to 100 parts by weight of a main component satisfying the above-mentioned x, y and z of 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100.
0.1 to 15 parts by weight in terms of _{2 is} added and contained, and cordierite is the main crystal (glass ceramics are excluded).
Q ), relative permittivity of 4 to 6, Q at measurement frequency of 10 GHz
A dielectric resonator having a value of 2000 or more.