JPH11214812A - High frequency wiring circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency wiring board capable of improving the high frequency transmission characteristics by using an insulation substrate having a low dielectric constant and a high Q value. SOLUTION: A high frequency wiring board has a wiring layer capable of transmitting a high frequency signal higher than 1 GHz on the surface or inside of an insulation board. The insulation board 1 is a compound oxide having B and Si as metal elements, and has a weight ratio composition of oxides of respective metal elements expressed as xB2 O3 .ySiO2 , where x and y satisfy 0.1<=x<=20, 80<=y<=99.9 and x+y=100, and a Q value at 10 GHz is over 2,000.

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 wiring layer composed of a strip line, a microstrip line, a coplanar line, a dielectric waveguide line and the like. .

[0002]

2. Description of the Related Art In high-frequency circuits used at high frequencies such as microwaves and millimeter waves, it is necessary to use a material having a low relative dielectric constant and a small dielectric loss (tan δ) (a large Q value) for a substrate. For this reason, conventionally, as a dielectric material, alumina porcelain mainly having a relative dielectric constant of about 10 and a Q value of 20,000 or more at a measurement frequency of 10 GHz 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 a sintering temperature range is extremely narrow, it is difficult to obtain a dense sintered body. It is known that 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 produced and used (for example, see JP-A-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 has a Q value of about 1000 at 10 GHz and has a high Q value in recent years. With the widespread use of dielectric resonators in the frequency band, there has been a demand for a low Q material having a higher Q value.

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, a high impedance microstrip line as shown in FIG. Then, there is a problem that the line width becomes too small to cause disconnection, and a relative line width variation becomes large, thereby increasing the defective 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, the impedance of a microstrip line in this type of porcelain substrate is inversely proportional to the relative dielectric constant and the width of the microstrip line when the thickness of the substrate is constant. In addition, the impedance can be increased by using a substrate material having a low relative dielectric constant. For this reason, a material having a lower dielectric constant has been demanded. Furthermore, when the transmission frequency increases from microwaves to millimeter waves, the transmission loss increases rapidly when the Q value is low, so that a lower loss material has been demanded.

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 GHz on or above an insulating substrate.
In the above-described high-frequency wiring board having a wiring layer capable of transmitting a high-frequency signal, the insulating substrate is a composite oxide including B and Si as metal elements, and a weight ratio of each metal element oxide. When the composition formula is expressed as xB ₂ O ₃ · ySiO ₂ , the x and y are 0.1 ≦ x ≦ 20, 80 ≦ y ≦
99.9, x + y = 100 and 10G
The Q value at Hz is 2000 or more.

Further, the insulating substrate of the high-frequency wiring substrate is a composite oxide comprising B and Si as metal elements, and the composition ratio by weight of each metal element oxide is xB ₂ O ₃ .yS.
When expressed as iO ₂ , x and y are 0.1 ≦ x ≦ 20, 80 ≦
a main component satisfying y ≦ 99.9, x + y = 100, and at least one of Group 4a elements of the periodic table in an amount of 0.1% by weight or more in terms of oxide based on 100 parts by weight of the main component; or At least one of the rare earth elements is contained in an amount of 0.1 parts by weight or more in terms of oxide. Here, 0.1 to 10 parts by weight of at least one of Group 4a elements in the periodic table in terms of oxide or 100% by weight of at least one of rare earth elements with respect to 100 parts by weight of the main component. .
It is desirable to contain 1 to 15 parts by weight.

Further, on the surface or inside of the insulating substrate,
In a high-frequency wiring board provided with a wiring layer capable of transmitting a high-frequency signal having a frequency of 1 GHz or more, the insulating substrate is a composite oxide made of Mg and Si as metal elements, and is made of a metal oxide. The molar ratio composition formula is aMgO
-When expressed as bSiO ₂ , the a and b are 15 ≦ a ≦ 3
9, 61 ≦ b ≦ 85, a + b = 100, cristobalite as a main crystal phase, a relative dielectric constant of less than 5, and a Q value at 10 GHz of 2,000 or more.

[0011]

In the high frequency wiring board of the present invention, the insulating substrate is
The relative dielectric constant is less than 5, and the Q value at 10 GHz is 2000
The above characteristics can be obtained, and high-frequency transmission characteristics can be improved by using such a dielectric ceramic having a low dielectric constant and a high Q value as an insulating substrate.

[0012]

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 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 entire surface electrode (ground) 2 is formed on the lower surface of the insulating substrate 1 and the microstrip line 3 is formed on the upper surface. A wiring layer is composed of the entire surface electrode (ground) 2 and the microstrip line 3. In this wiring layer, as a high frequency signal, 1 GHz or more, particularly 20 GHz or more,
A high frequency signal of 0 GHz or more is transmitted.

FIG. 1 illustrates an example in which a microstrip line is formed on the surface of the insulating substrate 1. However, for example, a strip line, a coplanar line, or a dielectric waveguide line may be formed. These wiring layers are desirably formed by simultaneous firing with the insulating substrate. 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, which are used at a high frequency such as a microwave and a millimeter wave.

In the high-frequency wiring board of the present invention,
When the insulating substrate 1, which expressed B as metal elements, a composite oxide comprising Si, the weight ratio composition formula by each metal element oxide and xB ₂ O ₃ · ySiO _2, wherein x, y is 0.
It satisfies 1 ≦ x ≦ 20, 80 ≦ y ≦ 99.9, x + y = 100.

The reason for limiting the component composition of the insulating substrate 1 to the above range is as follows. That is, x indicating the weight percentage of B ₂ O ₃ is set to 0.1 ≦ x ≦ 20 (80 ≦ y ≦ 99.9) when x is smaller than 0.1 (y is larger than 99.9). This is because the sintered body is not densified, and when x exceeds 20 (when y is smaller than 80), a good sintered body cannot be obtained and the Q value becomes low. X indicating the amount of B ₂ O ₃
Is from 0.2 to 1 in that the Q value is 3000 or more.
0% by weight (90 ≦ y ≦ 99.8) is desirable.

When the Q value at a measurement frequency of 10 GHz is 2000
The reason why it is desirable to satisfy the above is that the Q value is 2000
This is because the above case can sufficiently cope with an insulating substrate in a high frequency band in recent years. The Q value is preferably as high as possible, but in particular, the measurement frequency is 10 GHz.
Is preferably 3000 or more.

In the sintered body constituting the substrate, the main phase is a glass phase, and in addition, cristobalite,
Tridymite, quartz, etc. may precipitate, but the precipitated phase differs depending on the composition. In the dielectric ceramic composition of the present invention, only the glass phase may be used.

The insulating substrate of the present invention uses, for example, B ₂ O ₃ powder and SiO ₂ powder as raw material powders, weighs them at a predetermined ratio, wet-mixes them, and then dries them. , And the molded product is placed in the atmosphere 125
It is obtained by firing at 0 to 1400 ° C.

The insulating substrate of the present invention is made of B or Si as a metal element. For example, Al, Ca, Ba, Zr, N
In some cases, i, Fe, Cr, P, Na, Ti and the like may be mixed. In this case, too, a ceramic having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

The insulating substrate of the high-frequency wiring board according to the present invention is a composite oxide comprising B and Si as metal elements, and the weight ratio composition formula of each metal element oxide is xB ₂ O.
_When expressed as ₃ · ySiO ₂ , the x and y are 0.1 ≦ x ≦
20, 80 ≦ y ≦ 99.9, x + y = 100, and 100 parts by weight of the main component with respect to the fourth part of the periodic table.
At least one of group a elements may be contained in an amount of 0.1 part by weight or more in terms of oxide.

Here, the main component is limited to such a composition for the above reason. In this high-frequency wiring board, at least one of Group 4a elements in the periodic table is 0.1 parts by weight or more, preferably 0.1 to 10 parts by weight in terms of oxide, based on 100 parts by weight of the main component. It contains.

Thus, for 100 parts by weight of the main component,
The reason that at least one element of Group 4a of the periodic table is contained in an amount of 0.1 part by weight or more in terms of oxide is that the Q value is further improved in this range. On the other hand, if it is less than 0.1 part by weight, the effect of the addition is small. In order to make the relative dielectric constant 4 or less, it is desirable to contain 0.1 to 10 parts by weight. Examples of Group 4a elements of the periodic table include Ti, Zr, and Hf. Among them, Ti is desirable because the raw material is inexpensive and the Q value is high.

The insulating substrate of the high-frequency wiring board of the present invention comprises:
As a raw material powder, for example, B ₂ O ₃ powder, SiO ₂ powder, TiO ₂ powder, ZrO ₂ powder, and HfO ₂ powder are weighed at a predetermined ratio, wet-mixed, dried, and dried. , And molding is performed by firing the molded body at 1250 to 1400 ° C. in the air.

In the insulating substrate of the present invention, the main phase is a glass phase, and in addition, cristobalite, tridymite, quartz, oxides of Ti, Zr, and Hf elements may be precipitated as crystal phases. The precipitation phase differs depending on the composition.

It should be noted that the insulating substrate of the high-frequency wiring board of the present invention comprises B, Si and Ti, Zr, Hf as metal elements.
Although containing elements, for example, Al, Ba, Ni, Fe, Cr,
In some cases, Ca, P, Na, and the like are mixed. In this case, too, a ceramic having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

The insulating base of the high-frequency wiring board according to the present invention contains at least one rare earth element in an amount of 0.1% by weight or more in terms of oxide based on 100 parts by weight of the main component. May be. The reason that at least one of Y and the rare earth element is further included in an amount of 0.1 part by weight or more based on 100 parts by weight of the main component is that the Q value is further improved in this range.
On the other hand, if it is less than 0.1 part by weight, the effect of the addition is small. And, in order to make the relative dielectric constant 4 or less, it is desirable to contain 0.1 to 15 parts by weight.

From the viewpoint of improving the Q value and lowering the dielectric constant, it is particularly desirable that the rare earth element be contained in an amount of 0.1 to 10 parts by weight in terms of oxide based on 100 parts by weight of the main component.

As rare earth elements, Sc, Y, La, C
e, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
There are y, Ho, Er, Tm, Yb, and Lu. Of these, Y, La, Nd, Sm, Dy, Yb, and Lu are most desirable because of their high Q value.

The insulating base of the high-frequency wiring board of the present invention comprises:
As a raw material powder, for example, at least one oxide powder of B ₂ O ₃ powder, SiO ₂ powder, and rare earth element is used, weighed at a predetermined ratio, wet-mixed, dried, and dried. , And molding is performed by firing the molded body at 1250 to 1400 ° C. in the air.

In the insulating substrate of the high-frequency wiring board according to the present invention, the main phase is a glass phase, and other crystal phases such as cristobalite, tridymite, quartz, and oxides in which a rare earth element is combined with Si are precipitated. May be
The precipitation phase differs depending on the composition.

The insulating substrate of the high-frequency wiring board according to the present invention contains B, Si and a rare earth element as metal elements. For example, Al, Ba, Zr as impurities in pulverized balls or raw material powders. , Ni, Fe, Cr, C
Although a, P, Na, Ti and the like may be mixed in this case, a ceramic having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

Further, the insulating substrate 1 of the high-frequency wiring board according to the present invention is a composite oxide comprising Mg and Si as metal elements, wherein the molar ratio composition formula of each metal element oxide is aMgO.bSiO ₂ . When expressed, a and b may satisfy 15 ≦ a ≦ 39, 61 ≦ b ≦ 85, and a + b = 100.

The reason for limiting the component composition of the insulating substrate to the above range is as follows. That is, the molar percentage of MgO, a, is set to 15 ≦ a ≦ 39 (61 ≦ b ≦ 85) when a is smaller than 15 (b is larger than 85) without densification of the sintered body. , A exceeds 39 (when b is less than 61), the relative dielectric constant becomes 5 or more. Also, a good sintered body cannot be obtained and the Q value becomes low. In particular, a indicating the amount of MgO is 20 ≦ a ≦ 39 (61 ≦ b ≦ 8) from the viewpoint that the Q value is 3000 or more.
0) is desirable. In particular, the relative permittivity is small and the Q value is 300
From the viewpoint of being 0 or more, 20 ≦ a ≦ 30 (70 ≦ b
≦ 80) is desirable.

In the sintered body constituting the substrate, the main crystal phase is cristobalite, and in addition, tridymite, quartz, or the like may be precipitated as a crystal phase, but the precipitated phase differs depending on the composition.

The insulating substrate of the present invention uses, for example, MgCO ₃ powder and SiO ₂ powder as raw material powders, weighs them at a predetermined ratio, wet-mixes them, and then dries them. And then pulverized for 0.5 to 3 hours. An appropriate amount of a binder is added to the obtained powder to form a compact.
For 0.5 to 3 hours.

In the aMgO.bSiO ₂ -based composition, control of the raw material powder and the sintering conditions is performed to improve the sinterability of the composition in which the sintering is difficult in a range of less than 39 mol% of MgO. Required. For example, it is also improved sinterability by using amorphous SiO ₂ powder as SiO ₂ powder. That is, the above-mentioned composition which could not be densified in Japanese Patent Application No. 7-339780 filed by the present inventors previously can be densified.

The insulating substrate of the present invention is composed of Mg, Si, or the like as a metal element. For example, Al, Ca, Ba, Z
In some cases, r, Ni, Fe, Cr, P, Na, Ti and the like may be mixed. In this case, too, a ceramic having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

[0038]

EXAMPLES Example 1 95% pure B ₂ O ₃ and 99% pure S as raw material powders
Using iO ₂ powders, these were weighed so that the sintered body had the composition shown in Table 1, wet-mixed for 15 hours, and then dried.
The obtained powder was granulated by adding an appropriate amount of a binder, and this was molded under a pressure of 1000 kg / cm ² to have a diameter of 60 m.
A molded product having a thickness of 5 mm was obtained. Table 1
Baking for 2 hours at the temperature shown in the table, diameter 50mm, thickness 0.2m
The substrate was polished to m. A whole surface electrode (ground) made of Cu is formed on one surface of the substrate, and a microstrip line made of Cu having a width of 0.4 mm is formed on the other surface, and the high frequency transmission line shown in FIG. It was measured.

The relative permittivity and the Q value were measured with a diameter of 10 mm,
A sintered body having a thickness of about 5 mm was prepared and measured at 20 GHz by the dielectric resonator method. Qf is Qf
= The Q value at 10 GHz was determined assuming that it was constant. Table 1 shows the results.

[0040]

[Table 1]

According to Table 1, the insulating substrate used in the present invention has a high Q value of 2000 or more at a measurement frequency of 10 GHz, and a transmission loss of 15 dB or less at 20 GHz. Moreover, it can be seen that the relative permittivity is as low as 3.8 or less.

As a comparative example, a transmission loss was measured at a frequency of about 20 GHz in the high-frequency transmission line shown in FIG. 1 using a glass substrate having a relative dielectric constant of 4 and a Q value of 1000 at a measurement frequency of 10 GHz. 24d
B / m. This shows that the sample of the present invention has smaller transmission loss and better high-frequency transmission characteristics than the comparative example.

Example 2 B ₂ O _{3 having} a purity of 95% and S having a purity of 99% were used as raw material powders.
iO ₂ powder, purity of 99% or more of the TiO ₂ powder, ZrO ₂
Powder and HfO ₂ powder were weighed so that the sintered body had the composition shown in Table 2, and wet-mixed for 15 hours.
The resulting powder was dried, granulated by adding an appropriate amount of a binder to the powder, and 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. The molded body was fired at the temperature shown in Table 2 for 2 hours and polished to a diameter of 50 mm and a thickness of 0.2 mm to obtain a substrate. Cu on one side of this substrate
On the other surface, a 0.4 mm-width Cu microstrip line was formed on the other surface electrode (ground), and the high-frequency transmission line shown in FIG. 1 was manufactured, and the transmission loss at 20 GHz was measured.

The relative permittivity and Q value were measured with a diameter of 10 mm,
A sintered body having a thickness of about 5 mm was prepared and measured at 20 GHz by the dielectric resonator method. Qf is Qf
= The Q value at 10 GHz was determined assuming that it was constant. Table 2 shows the results.

[0045]

[Table 2]

As can be seen from Table 2, the sample of the present invention has a capacity of 10 G
It can be seen that the Q value in Hz is 2000 or more and the transmission loss at 20 GHz is 15 dB or less. In addition, 4
Group a element oxide is 0. At 10 to 10 parts by weight, the relative dielectric constant is 4 or less, indicating that the width of the microstrip line can be increased.

Example 3 As raw material powder, 95% pure B ₂ O ₃ and 99% pure S
Using iO ₂ powder and oxide powder of a rare earth element having a purity of 99% or more, these were weighed so that the sintered body had the composition shown in Table 3, wet-mixed for 15 hours, and dried, and the obtained powder was obtained. Add an appropriate amount of binder and granulate,
Molded under pressure of g / cm ² , diameter 60 mm, thickness 5 m
m was obtained. This molded body was fired at the temperature shown in Table 3 for 2 hours and polished to a diameter of 50 mm and a thickness of 0.2 mm to obtain a substrate. A full-surface electrode (ground) made of Cu is formed on one surface of this substrate, and a microstrip line made of 0.4 mm-width Cu is formed on the other surface. The high-frequency transmission line shown in FIG. 1 is manufactured, and transmission loss at 20 GHz is reduced. It was measured.

The relative permittivity and the Q value were measured with a diameter of 10 mm,
A sintered body having a thickness of about 5 mm was prepared and measured at 20 GHz by the dielectric resonator method. Qf is Qf
= The Q value at 10 GHz was determined assuming that it was constant. Table 3 shows the results.

[0049]

[Table 3]

As shown in Table 3, the sample of the present invention has a
It can be seen that the Q value in Hz is 2000 or more and the transmission loss at 20 GHz is 15 dB or less. Furthermore, when the added amount of the rare earth element oxide is 0.1 to 15 parts by weight, the relative dielectric constant is 4 or less, which indicates that the width of the microstrip line can be increased.

EXAMPLE 4 MgCO _{3 having} a purity of 99% and SiO ₂ powder having a purity of 99% were used as raw material powders, weighed so that the sintered body had the composition shown in Table 4, and wet-mixed for 15 hours. The mixture was dried, calcined at 1200 ° C. for 2 hours, and then pulverized. Add an appropriate amount of binder to the obtained powder and granulate,
This 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. The molded body was fired in the atmosphere at a temperature shown in Table 4 for 2 hours and polished to a diameter of 50 mm and a thickness of 0.2 mm to obtain a substrate.

A whole-surface electrode (ground) made of Cu was formed on one surface of this substrate, and a microstrip line made of Cu having a width of 0.3 mm was formed on the other surface. The high-frequency transmission line shown in FIG. Transmission loss was measured.
Measurement of relative permittivity and Q value is 10mm in diameter and about 5mm in thickness
Was prepared, and the Q value at 10 GHz was measured by the dielectric resonator method. The results are shown in Table 4.

[0053]

[Table 4]

According to Table 4, the insulating substrate used in the present invention has a low relative dielectric constant of less than 5, and has a measurement frequency of 10
Q value at GHz shows a high value of 2000 or more, and 20G
It can be seen that the transmission loss at 15 Hz is 15 dB or less.

[0055]

According to the high frequency wiring board of the present invention, the Q value of the insulating substrate at 10 GHz is as high as 2000 or more, so that the transmission loss is 15 dB / m at a frequency of 20 GHz.
The following can be achieved, and high-frequency transmission characteristics can be improved. Further, since the relative permittivity of the insulating substrate is as low as less than 5, the width of the wiring layer formed on the insulating substrate can be increased.

[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 substrate 2 ... Full surface electrode (ground) 3 ... Microstrip line

Claims (4)

[Claims] 1. A frequency 1 on the surface 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 made of B and Si as metal elements, and the weight of each metal element oxide is reduced. XB ₂ O ₃ .ySi
When expressed as O ₂ , the x and y are 0.1 ≦ x ≦ 20, 80
≦ y ≦ 99.9, x + y = 100,
A high frequency wiring board, wherein the Q value at 10 GHz is 2000 or more. 2. The method according to claim 1, wherein a frequency of 1
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 made of B and Si as metal elements, and the weight of each metal element oxide is reduced. XB ₂ O ₃ .ySi
When expressed as O ₂ , the x and y are 0.1 ≦ x ≦ 20, 80
A main component satisfying ≦ y ≦ 99.9, x + y = 100;
0.1 parts by weight or more of at least one element of Group 4a of the periodic table in terms of oxide with respect to 100 parts by weight of the main component,
Alternatively, a high-frequency wiring board containing at least one rare earth element in an amount of 0.1 part by weight or more in terms of oxide. 3. The periodic table No. 4 based on 100 parts by weight of the main component.
at least one of group a elements is 0.1 to
3. The high-frequency wiring board according to claim 2, wherein the wiring board contains 0.1 to 15 parts by weight of at least one of rare earth elements in terms of oxide. 4. The method of claim 1, wherein a frequency of 1
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 containing Mg and Si as metal elements, The specific composition formula is aMgO · bSi
When represented as O ₂ , the a and b are 15 ≦ a ≦ 39, 61 ≦
It satisfies b ≦ 85, a + b = 100, has cristobalite as a main crystal phase, has a relative dielectric constant of less than 5, and 1
A high-frequency wiring board, wherein the Q value at 0 GHz is 2000 or more.