JPH11100258A - Wiring substrate for high frequency application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the wiring substrate for high frequency application, which is capable of improving the high frequency transmission characteristics by using the dielectric porcelain having a low dielectric constant and a high Q value as the insulating substrate. SOLUTION: The wiring substrate for high frequency application is constituted by the arrangement of the wired layer capable of transmitting high frequency signal having a frequency of >=1 GHz on the surface and/or in the inner part of the insulating substrate 1 which is a composite oxide containing Mg, Al and Si as metal element. The composition of the oxides of these metals is shown by the molar-ratio compositional formula; xMgO.yAl2 O3 .zSiO2 , where x, y and z satisfy the following formulas; 10<=x<=40, 10<=y<=40, 20<=z<=80 and x+y+z=100. The composite oxide consists of the above main component 60-99.9 wt.% and at least one element selected from among La, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, Ce, Ti, Sm and Y in an amount of 0.1-40 wt.% expressed in terms of its oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency wiring board, and more particularly to a high-frequency wiring board having a strip line, a microstrip line, a coplanar line, a dielectric waveguide, and the like.

[0002]

2. Description of the Related Art In a high-frequency circuit used in a high-frequency range such as a microwave and a millimeter wave, a substrate must be made of a material having a low relative dielectric constant and a small dielectric loss (tan δ) (a large Q value). For this reason, conventionally, as a substrate material, the relative dielectric constant is mainly about 10, and the measurement frequency is 10 GHz.
Alumina porcelain having a Q value of 20000 or more has been adopted (see, for example, JP-A-62-103904).

On the other hand, cordierite is conventionally known as a material having a low relative dielectric constant. However, since the firing temperature range is extremely narrow, it is difficult to obtain a dense sintered body. Relative permittivity 4-6, measurement frequency 1
Glass ceramics having a Q value of about 1000 at 0 GHz are known (for example, see Japanese Patent Application Laid-Open No. 61-234128).

[0004]

However, porcelain such as glass ceramics used as a low dielectric constant material has a small relative dielectric constant of 4 to 6, but a Q value of 1 GHz at 10 GHz.
A low dielectric constant material having a higher Q value of about 000 has been demanded.

On the other hand, alumina porcelain has a high Q value at 10 GHz of 20,000 or more, but has a relatively high relative dielectric constant of about 10, so that, for example, when a high impedance strip line as shown in FIG. There has been a problem that the line width becomes too small to cause disconnection, and a relative line width variation becomes large, thereby increasing the failure rate of the microwave integrated circuit. In addition, there is a problem in that crosstalk occurs due to the narrow line interval.

On the other hand, if the thickness of the substrate is constant, the impedance of the strip line in this type of porcelain substrate is inversely proportional to the relative dielectric constant and the width of the strip line. By using a substrate material having a low relative dielectric constant, the impedance can be increased, and therefore, a material having a lower dielectric constant has been demanded. Further, when the transmission frequency increases from microwaves to millimeter waves, the transmission loss increases rapidly when the Q value is low, so that a material having a lower loss has been required.

It is an object of the present invention to provide a high-frequency wiring board that can improve high-frequency transmission characteristics by using a sintered body having a low dielectric constant and a high Q value as an insulating substrate material.

[0008]

According to the present invention, there is provided a high-frequency wiring board having a frequency of 1 on the surface and / or inside of an insulating substrate.
In a high-frequency wiring board provided with a wiring layer capable of transmitting a high-frequency signal of GHz or more, the insulating substrate is a composite oxide including Mg, Al, and Si as metal elements, and oxidizing each metal element. XMg
When expressed as O.yAl ₂ O ₃ .zSiO ₂ ,
y, z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40, 20 ≦ z
≦ 80, main components 60-9 satisfying x + y + z = 100
9.9% by weight, La, Pr, Nd, Eu, Gd, T
b, Dy, Ho, Er, Tm, Lu, Ce, Ti, Sm
And at least one of Y is 0.1 to 40% by weight in total in terms of oxides.

[0009]

According to the high frequency wiring board of the present invention, the insulating substrate is
60 to 99.9% by weight of the above main component, La, Pr,
Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, L
By obtaining at least one of u, Ce, Ti, Sm, and Y in the range of 0.1 to 40% by weight in terms of oxides, characteristics obtained by strictly controlling firing conditions such as firing temperature are obtained. Can be improved without greatly deteriorating the firing conditions. That is, a low dielectric constant and high Q value characteristic having a relative dielectric constant of 7 or less and a Q value at 10 GHz of 2000 or more can be obtained. To the extent that it is easy to manufacture and mass productivity can be improved.

The use of such a low dielectric constant, high Q value dielectric porcelain as an insulating substrate can improve high frequency transmission characteristics.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency wiring board according to the present invention is provided with a wiring layer capable of transmitting a high-frequency signal having a frequency of 1 GHz or higher on the surface and / or inside of an insulating substrate. As shown in FIG. 1, wiring layers 2 and 3 are formed on the surface of an insulating substrate 1.

That is, the wiring layer (ground) 2 is formed on the lower surface of the insulating substrate 1 and the wiring layer 3 (microstrip line) is formed on the upper surface. A high frequency signal of 1 GHz or more, particularly 20 GHz or more, and more preferably 50 GHz or more is transmitted to the wiring layers 2 and 3 as a high frequency signal.

FIG. 1 shows an example in which the wiring layer 3 which is a microstrip line is formed on the surface of the insulating substrate 1. For example, a strip line, a coplanar line, and a dielectric waveguide line are provided inside the insulating substrate 1. It may be formed. Further, such a high-frequency wiring board can be used for a package, a dielectric resonator, an LC filter, a capacitor, a dielectric waveguide, a dielectric antenna, and the like used in a high-frequency region such as microwaves and millimeter waves. .

In the high-frequency wiring board of the present invention,
Insulating substrate 1, when representing the molar ratio composition formula a _{xMgO · yAl 2 O 3 · zSiO} 2 of an oxide of a metal element, the x, y, z is 10 ≦ x ≦ 40,10 ≦ y ≦ 40,20 ≤
Those satisfying x ≦ 80 and x + y + z = 100 are the main components.

The main component composition of the substrate is limited to the above range for the following reason. That is, x indicating the molar percentage of MgO is set to 10 to 40 mol% because x is 10 mol%.
If it is smaller than this, a good sintered body cannot be obtained and the Q value becomes low, and if it exceeds 40 mol%, the relative dielectric constant becomes high. In particular, x indicating the amount of MgO is desirably 15 to 35 mol% from the viewpoint that the Q value is 5000 or more.

The reason why y, which represents the mole percentage of Al ₂ O ₃ , is set to 10 to 40 mol% is that when y is less than 10 mol%, a good sintered body cannot be obtained and the Q value becomes low. If it exceeds 40 mol%, the relative dielectric constant will increase. Particularly, y indicating the amount of Al ₂ O ₃ is desirably 17 to 35 mol% from the viewpoint that the Q value is 5000 or more.

The z representing the molar percentage of SiO ₂ is 20 to 8
The reason why 0 mol% is set is that when z is smaller than 20 mol%, the relative dielectric constant increases, and when z exceeds 80 mol%, a good sintered body cannot be obtained and the Q value decreases. In particular, z indicating the amount of SiO ₂ is 30 to 6 from the viewpoint that the Q value is 5000 or more.
0 mol% is desirable.

According to the present invention, the insulating substrate contains 60 to 99.9% by weight of the main component and La, Pr, Nd,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, C
At least one of e, Ti, Sm, and Y is 0.1 to 40% by weight in terms of each oxide.

The main component is 60 to 99.9% by weight, La, P
The reason that r and the like are 0.1 to 40 parts by weight in terms of oxides is that the main component is more than 99.9% by weight (when La and Pr are less than 0.1% by weight in terms of oxides). The densification firing temperature is not wide, and when the main component is less than 0.01% by weight (when La, Pr, etc. is more than 40% by weight in terms of oxide), the relative dielectric constant increases and the firing temperature range increases. However, it becomes narrower. As the content of La, Pr, etc. increases, the densification firing temperature increases, but on the other hand, the relative dielectric constant increases and the Q value decreases. It is desirable to determine the content.

The insulating substrate according to the present invention has the following characteristics: 15 ≦ x ≦ 35, 17 ≦ y ≦ 35, 30
≤x≤60, and a Q value of 7
In order to be 000 or more, 20 ≦ x ≦ 30, 17 ≦ y ≦
It is more desirable to satisfy 30, 40 ≦ x ≦ 60.

In the insulating substrate of the present invention, in particular, the composition of cordierite, that is, x = 22.2, y = 22.2, z = 5
At 5.6, La, Pr, Nd, Eu, Gd, Tb, D
at least one of y, Ho, Er, Tm, Lu, Ce, Ti, Sm, and Y in terms of their respective oxides.
It is desirable to contain 1 to 10 wt%. Among these elements, La, in that it is a practical (cheap) material,
Y and Ti are desirable.

For the insulating substrate, the measurement frequency is 10 GHz
The reason why the Q value at 2000 is to satisfy 2000 or more is that Q
When the value is 2000 or more, it is possible to sufficiently cope with an insulating substrate in a high frequency band in recent years.
The Q value is preferably as high as possible.
It is desirable that the Q value at z is 5000 or more.

In the insulating substrate of the present invention, the main phase is cordierite, and the other crystalline phases are mullite, spinel, protoenstatite, clinoenstatite,
Forsterite, cristobalite, tridymite,
Safarin, quartz, etc. precipitate, and La, Pr,
Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, L
An oxide compound of at least one of u, Ce, Ti, Sm and Y and a main component element may be precipitated.
The precipitation phase differs depending on the composition.

The insulating substrate of the present invention may be made of, for example, MgCO ₃ powder, Al ₂ O ₃ powder, SiO ₂ powder, LaO powder, PrO powder, Nd ₂ O ₃ powder, Eu ₂
O ₃ powder, Gd ₂ O ₃ powder, Tb ₂ O ₃ powder, Dy ₂ O
₃ powder, Ho ₂ O ₃ powder, Er ₂ O ₃ powder, Tm ₂ O ₃
Powder, Lu ₂ O ₃ powder, CeO ₂ powder, TiO ₂ powder,
Sm ₂ O ₃ powder and Y ₂ O ₃ powder were weighed at a predetermined ratio, wet-mixed and dried, and the mixture was calcined in the atmosphere at 1100 to 1300 ° C. for 0.5 to 3 hours. Crushed. It is obtained by adding an appropriate amount of a binder to the obtained powder and molding, and firing this molded body at 1200 to 1450 ° C in the air. In particular, since dielectric porcelain having cordierite as a main crystal phase is difficult to sinter, it is necessary to find an appropriate firing temperature and to fire at a strictly controlled firing temperature.

It should be noted that the insulating substrate of the high-frequency wiring board of the present invention comprises Mg, Al, Si, La, P
r, Nd, Eu, Gd, Tb, Dy, Ho, Er, T
m, Lu, Ce, Ti, Sm, and Y. For example, as impurities in pulverized balls or raw material powders,
In some cases, Ca, Ba, Zr, Ni, Fe, Cr, P, Na, and the like are mixed, but even in this case, as long as the above composition is satisfied, a low dielectric constant and a high Q value can be obtained.

[0026]

EXAMPLES As raw material powder, 99% pure MgCO ₃ powder, 99.7% pure Al ₂ O ₃ powder, 99.4% pure
Of SiO ₂ powder, La ₂ O ₃ powder of 99.9% purity, P
r ₂ O ₃ powder, Nd ₂ O ₃ powder, Eu ₂ O ₃ powder, Gd
₂ O ₃ powder, Tb ₂ O ₃ powder, Dy ₂ O ₃ powder, Ho ₂
O ₃ powder, Er ₂ O ₃ powder, Tm ₂ O ₃ powder, Lu ₂ O
₃ powder, CeO ₂ powder, TiO ₂ powder, Sm ₂ O ₃ powder, and Y ₂ O ₃ powder were weighed so that the sintered body had the composition shown in Tables 1 to 5, and wet-mixed for 15 hours. Thereafter, the mixture was dried, and the mixture was calcined at 1200 ° C. for 2 hours and then pulverized.

The obtained powder was granulated by adding an appropriate amount of a binder, and the obtained powder was molded under a pressure of 1000 kg / cm ² to obtain a molded body having a diameter of 60 mm and a thickness of 5 mm. This molded body was fired in the air at the temperatures shown in Tables 1 to 2 for 2 hours, and polished to a diameter of 50 mm and a thickness of 0.2 mm to obtain a substrate. A microstrip line made of Cu having a width of 0.3 mm was formed on this substrate, and a high-frequency transmission line shown in FIG.
The transmission loss at 20 GHz was measured.

For measurement of relative permittivity and Q value, diameter 10
A sintered body having a thickness of 5 mm and a thickness of 5 mm was prepared, and the value at 10 GHz was measured by the dielectric resonator method. The results are shown in Tables 1 to 5.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

[Table 5]

Tables 1 to 5 show that the insulating substrate used in the present invention has a low relative dielectric constant of 7 or less and a high Q value of 2000 or more at a measurement frequency of 10 GHz. Moreover, it can be seen that the high-frequency transmission line shown in FIG. 1 exhibits a transmission loss of 15 dB / m or less at a frequency of 20 GHz.

As a comparative example, a substrate made of glass ceramics was manufactured. The relative permittivity of this substrate is 5.6,
The Q value at a measurement frequency of 10 GHz is 1000, and FIG.
In the high-frequency transmission line shown in FIG. 7, the transmission loss was 24 dB / m at a frequency of 20 GHz.

[0036]

According to the high frequency wiring board of the present invention, the insulating substrate has a molar ratio composition formula of xMgO.yAl ₂ O ₃ .zSiO.
₂ and La, Pr, Nd, Eu, G
d, Tb, Dy, Ho, Er, Tm, Lu, Ce, T
Since at least one of i, Sm and Y consists of 0.1 to 40% by weight in terms of their oxides, they have a low relative dielectric constant of 7 or less and a Q value at 10 GHz of 2000.
It has a high Q value as described above, thereby improving high-frequency transmission characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a high-frequency wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating board 2 ... Wiring layer pole (ground) 3 ... Wiring layer pole (microstrip line)

Claims (1)

[Claims] 1. A high-frequency wiring board having a wiring layer capable of transmitting a high-frequency signal having a frequency of 1 GHz or more disposed on a surface and / or inside of an insulating substrate. a composite oxide comprising Si, when the molar ratio composition formula 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 x + y + z = 100 60 to 99.9% by weight of the main component satisfying
r, Nd, Eu, Gd, Tb, Dy, Ho, Er, T
at least one of m, Lu, Ce, Ti, Sm, and Y is 0.1 to 40% by weight in total in terms of their oxides.
A high-frequency wiring board, comprising: