JP4645935B2 - Low-temperature fired porcelain composition and method for producing the same - Google Patents

Description

  The present invention relates to a low-temperature fired porcelain composition for a laminated circuit board, in particular, a low dielectric constant at a high frequency, a high fQ value (f is a resonance frequency), and a low melting point electrode material such as silver, gold, or copper. The present invention relates to a low-temperature fired ceramic composition capable of simultaneous firing and a method for producing the same.

2. Description of the Related Art Conventionally, a ceramic laminated circuit board on which a semiconductor element such as an IC and various electronic components are mounted and an inner layer circuit is arranged is known. An alumina substrate has been used as a material for such a laminated circuit board. Since the firing temperature of the alumina substrate is as high as 1300 to 1600 ° C., a high melting point metal such as W or Mo is used as the electrode material. However, these electrode materials have a high electrical resistivity and a problem that signal transmission loss increases.
Moreover, since the relative dielectric constant (ε10) of alumina itself is high, there is a problem of transmission signal delay. Therefore, Patent Document 1 discloses a material suitable for a circuit board that supports high frequency transmission signals (GHz band or higher), and can be simultaneously fired with an electrode material such as silver, gold, or copper having a low electrical resistivity. A low-temperature fired ceramic composition using a cordierite crystal phase having a low dielectric constant (ε5.5) and a high f · Q value as a base material is disclosed.
Japanese Patent Publication No.6-2619

However, the low-temperature fired porcelain composition using cordierite crystal as a base material requires a large amount of sintering aid such as B ₂ O _{3 in} order to obtain a dense porcelain, resulting in a decrease in f · Q value. In addition, the firing temperature is 950 ° C. or higher, and the simultaneous firing with the silver electrode material has a problem that the difference between the firing temperature and the melting temperature of silver is small. Also, boron evaporates during calcination, damages the furnace material, reacts with the electrode material during firing, dissolves in water and alcohol during the manufacturing process, segregates during drying, and reacts with the organic binder used. It was necessary to solve problems such as deteriorating the performance of the binder.
Accordingly, an object of the present invention is to provide an electrode material such as silver, gold, or copper at a low temperature of 1000 ° C. or lower, and further at a low temperature of 900 ° C. or lower, while reducing the amount of B ₂ O ₃ that is a sintering aid. A low-temperature fired porcelain composition in which a cordierite crystal phase having a low relative dielectric constant and a high f · Q value is precipitated, and a method for producing the same are provided. With the goal.

The first invention is a low-temperature fired porcelain composition having cordierite (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) crystals in the structure, the main component being composed of oxides of Mg, Al, and Si , Mg, Al, Si converted to MgO, Al ₂ O ₃ , and SiO ₂ , respectively, to a total of 100 wt%, 10 to 25 wt% in terms of MgO, 15 to 40 wt% in terms of Al ₂ O ₃ , SiO _It contains 45 to 65% by weight of Mg, Al, Si in terms of ₂ , and 0.1 to 5% by weight of B and CuO in terms of B ₂ O ₃ as subcomponents with respect to 100% by weight of the main component. 0.1 to 5% by weight of Cu, 0.1 to 10% by weight of Mn in terms of Mn ₃ O ₄ , a relative dielectric constant of 5.5 or less, f · Q value of 10,000 GHz or more, sintering density It is at 2.48g / cm ³ or more, less than 1200 ℃ Netsusho In a certain low temperature sintered ceramic composition characterized by being prepared.
In the present invention, as subcomponents, at least one of Bi to O ₂ wt% in terms of Bi ₂ O ₃ and 0 to 2.5 wt% in terms of ZnO may be contained.

The second invention is a method for producing the low-temperature fired ceramic composition of the first invention, wherein the main component raw materials MgO, Al ₂ O ₃ and SiO ₂ are temporarily added at a temperature of 900 ° C. or higher and lower than 1200 ° C. a first calcination step of tempering, the first calcined powder obtained through the first calcination step, mixed _B 2 _O 3, CuO, and _Mn 3 _{O 4} as a sub-component, 700 ° C. A molded body using the second calcined powder obtained through the second calcined process and the second calcined process, which is calcined at a temperature lower than the calcining temperature in the first calcining process. And a firing step in which the compact is fired at a temperature higher than the firing temperature in the second calcining step at a temperature of 1000 ° C. or less. In the firing step, cordierite (2MgO · 2Al of ₂ O ₃ · 5SiO ₂₎ low temperature sintering ceramic composition to precipitate crystals It is a production method.
As a secondary component, at least one of Bi ₂ O ₃ and ZnO may be mixed with the first calcined powder together with B ₂ O ₃ , CuO, and Mn ₃ O ₄ .

  Since the low-temperature fired ceramic composition of the present invention is a material that can be sintered at a low temperature of 1000 ° C. or lower, and further 900 ° C. or lower, it is simultaneously fired with an electrode material such as silver, gold, or copper to form a laminated circuit board. Can do. In addition, since it is a material having a low relative dielectric constant (ε5.5 or less) and a high f · Q value (f · Q10000 GHz or more), it is suitable for a high-frequency laminated circuit board and the like.

In the present invention, the reason why the composition range of each component and the temperature range in the first and second calcining steps are specified is as follows.
First, Mg, Al, and Si, which are main components, will be described. When Mg is less than 10% by weight in terms of MgO, the cordierite (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) crystal ratio that precipitates at the time of firing at a low temperature of 1000 ° C. or lower decreases, and the relative dielectric constant is high. The f · Q value cannot be obtained. On the other hand, when the amount is more than 25% by weight, the ratio of cordierite crystals precipitated during firing similarly decreases at a low temperature of 1000 ° C. or lower, and a low relative dielectric constant and a high f · Q value cannot be obtained. When the amount is particularly large, the amount of enstatite (MgO.SiO ₂ ) (ε6.5) having a high relative dielectric constant is increased, and a low relative dielectric constant cannot be obtained.

If Al is less than 15% by weight in terms of Al ₂ O ₃ , the ratio of cordierite crystals precipitated during firing at a low temperature firing of 1000 ° C. or lower is reduced, and a low relative dielectric constant and a high f · Q value cannot be obtained. .
On the other hand, when the amount is more than 40% by weight, the ratio of cordierite crystals precipitated during firing similarly decreases at a low temperature of 1000 ° C. or lower, and a low relative dielectric constant and a high f · Q value cannot be obtained. In addition, the sintered density is lowered and a dense porcelain composition cannot be obtained.

When Si is less than 45% by weight in terms of SiO ₂ , the ratio of cordierite crystals deposited during firing at a low temperature firing of 1000 ° C. or lower decreases, and a low relative dielectric constant and a high f · Q value cannot be obtained. On the other hand, when the amount is more than 65% by weight, the ratio of cordierite crystals precipitated during firing similarly decreases at a low temperature of 1000 ° C. or lower, and a low relative dielectric constant and a high f · Q value cannot be obtained. Further, the sintered density is lowered and a dense porcelain composition cannot be obtained.
In the composition range in which MgO, Al ₂ O ₃ and SiO ₂ as main components are limited, in addition to cordierite crystals, enstatite (MgO · SiO ₂ ) crystals, spinel (MgO · Al ₂ O ₃ ) crystals, There are cases where SiO2 crystals are precipitated, but since the amount of precipitation is very small, both have a dielectric constant of 5.5 or less, f · Q value of 10,000 GHz or more, and can be fired at a temperature of 1000 ° C. or less. A porcelain composition is obtained.

FIGS. 2 and ₃ show that raw materials mixed at a composition ratio of 13.78 wt% MgO, 34.86 wt% Al ₂ O ₃ , and 51.36 wt% SiO ₂ were fired at 1100 ° C. and 1300 ° C., respectively. It is a diffraction pattern by X-ray diffraction measurement (Cu-Kα ray) at times (referred to as the first calcination step in the present invention).
When fired at 1100 ° C., crystal phases of Al ₂ O ₃ and MgO.SiO ₂ (enstatite) were confirmed. Then, the crystal phase was confirmed in 1300 ° C. In _{2MgO · 2Al 2 O 3 · 5SiO} 2 ( cordierite). Although details will be described later, when cordierite is precipitated in the first calcination step (the calcination temperature is high), densification does not proceed in the subsequent calcination and desired dielectric properties cannot be obtained. In addition, when MgO.SiO ₂ does not precipitate (the calcining temperature is low), cordierite is insufficiently precipitated in the subsequent firing, and desired dielectric properties cannot be obtained. Therefore, the calcining temperature of Mg, Al, and Si, which are the main components, is set to a temperature of 900 ° C. or higher and lower than 1200 ° C. so as to have a crystal phase of Al ₂ O ₃ and MgO · SiO ₂ .

The following subcomponents are added to the first calcined powder adjusted as described above. B, Cu, and Mn may be essential as subcomponents, and Bi and Zn may be added as optional components.
B has an effect of promoting low-temperature sintering. If it is less than 0.1% by weight in terms of B ₂ O ₃ , sintering is insufficient in low-temperature firing at 1000 ° C. or less, and a dense porcelain composition cannot be obtained. On the other hand, when the content is more than 10% by weight, the f · Q value is lowered and a low-loss ceramic composition cannot be obtained, and foaming occurs in the sintered body, so that a dense ceramic composition cannot be obtained. For this reason, it is preferable that it is 0.1 to 10 weight%. More preferably, it is 5 weight% or less.

  Cu has an effect of promoting low-temperature sintering and an effect of promoting crystallization of cordierite during firing. If the amount is less than 0.1% by weight in terms of CuO, the effect cannot be obtained, and a dense porcelain composition cannot be obtained in low-temperature firing at 1000 ° C. or lower. On the other hand, if it is more than 5% by weight, the f · Q value is lowered and a low-loss ceramic composition cannot be obtained. For this reason, it is desirable that Cu is 0.1 to 5% by weight in terms of CuO. Preferably it is 0.5 to 2 weight%.

Mn also has an effect of promoting low-temperature sintering and an effect of promoting crystallization of cordierite during firing. If the amount is less than 0.1% by weight in terms of Mn ₃ O ₄ , the effect cannot be obtained, and a dense porcelain composition cannot be obtained in low-temperature firing at 1000 ° C. or lower. On the other hand, when the content is more than 10% by weight, the f · Q value decreases and a low loss ceramic composition cannot be obtained. For this reason, it is desirable that Mn is 0.1 to 10% by weight in terms of Mn ₃ O ₄ . Preferably it is 1 to 5 weight%.

Bi, like B, has the effect of promoting low temperature sintering. When the amount is more than 10% by weight in terms of Bi ₂ O ₃ , the relative dielectric constant increases and the f · Q value decreases, so that a low dielectric constant and low loss ceramic composition cannot be obtained. For this reason, Bi is preferably 0 to 10% by weight in terms of Bi ₂ O ₃ . Preferably it is 1 to 5 weight%.

  Zn has the effect of promoting low-temperature sintering and reducing the relative dielectric constant. When the amount is more than 2.5% by weight in terms of ZnO, the f · Q value is lowered, so that a low-loss porcelain composition cannot be obtained. Therefore, Zn is preferably 0 to 2.5% by weight in terms of ZnO.

  The first calcined powder to which the subcomponent adjusted as described above is added is calcined at a temperature of 700 ° C. or higher and lower than the calcining temperature in the first calcining step (the second calcining step in the present invention). Called). The reason why the temperature in the second calcination step is set to 700 ° C. or higher is that the SiO 2, MgO as the main component raw materials and the subcomponent additives are temperatures necessary for vitrification. The reason why the temperature is lower than the firing temperature is to prevent cordierite from precipitating in the second calcination step due to the sintering promoting effect of the subcomponent.

  In the present invention, depending on the component composition and calcining temperature conditions specified above, the dielectric constant is as small as 5.5 or less, the f · Q value is 10,000 GHz or more, and it can be fired at a temperature of 1000 ° C. or less. A low-temperature fired porcelain composition can be obtained. Therefore, the low-temperature fired ceramic composition of the present invention can be fired simultaneously with an electrode material having a low electrical resistivity such as silver, gold, and copper. Therefore, it is possible to construct a circuit board for high frequency (GHz band or more) having a very low loss and having a high f · Q value possessed by the low-temperature sintered porcelain composition of the present invention and suppressing loss due to electric resistance of the electrode material. .

Hereinafter, it demonstrates in detail as an Example.
MgO, Al ₂ O ₃ , and SiO ₂ powders as a cordierite raw material were weighed according to the weight ratio shown in Table 1, and mixed with a pure water with a ball mill for 20 hours. After the mixed slurry was heated and dried, it was pulverized with a cracker and placed in an alumina container and calcined at 1000 to 1150 ° C. for 2 hours (first calcining step). Next, the MgO—Al ₂ O ₃ —SiO ₂ calcined powder and B ₂ O ₃ , Bi ₂ O ₃ , CuO, Mn ₃ O ₄ , ZnO are weighed according to the weight ratios shown in Table 1, and together with pure water In addition, the mixture was mixed with a ball mill for 20 hours. After the mixed slurry was heated and dried, it was pulverized with a cracker and placed in an alumina container and calcined at 700 to 900 ° C. for 2 hours (second calcining step). The obtained calcined powder and pure water were put in a ball mill, pulverized for 40 hours, and heat-dried to obtain pulverized powder.
As a comparative example, Table 1 also shows the first calcining temperature outside the scope of the present invention.

An acrylic binder aqueous solution was added to the pulverized powder in an amount of 3 to 5 wt% of the binder solid content based on the weight of the pulverized powder, and then kneaded in a mortar and sized through a 32 mesh sieve to obtain granulated powder. This granulated powder was put into a mold and subjected to pressure molding at a pressure of 1 GPa to obtain a cylindrical molded body sample. This sample was heated in air at a rate of 200 ° C./h to 800 to 1050 ° C., held for 2 hours, and then cooled to room temperature at a rate of 200 ° C./h for firing.

The sintered density was calculated from the size and weight of the obtained sintered body. Then, to determine the unloaded Q value Q ₀ and the resonance frequency f ₀ by cylindrical resonator method. From the size of the fired body and f ₀ and Q ₀ , an f · Q value that is the product of the relative dielectric constant and the inverse of the dielectric loss coefficient tan δ and f ₀ was calculated. The resonance frequency _{f 0} was 13~16GHz. These results are shown in Table 1. In addition, the crystal phase of the sample was identified by X-ray diffraction measurement using Cu-Kα rays. The results are shown in Figs. A sample number without an asterisk is an example of the present invention, and a sample number with an asterisk is a comparative example outside the scope of the present invention.

From the results in Table 1, sample no. In 3, 5, and 6, since the subcomponent ratio is out of the scope of the invention, the relative permittivity increases, the f · Q value decreases, and a relative permittivity of 5.5 or less and f · Q10000 GHz or more cannot be obtained. . Sample No. In No. 11, since the subcomponent ratio is out of the scope of the invention, a dense sintered body cannot be obtained at a high firing temperature at 1000 ° C. or lower. Sample No. In No. 20, the composition ratio of MgO, which is a main component raw material, is out of the scope of the invention, so that the relative dielectric constant increases and a relative dielectric constant of 5.5 or less cannot be obtained. Sample No. No. 25 has a composition of only the main component MgO—Al ₂ O ₃ —SiO ₂ and does not contain subcomponents, so a dense sintered body cannot be obtained by firing at 1000 ° C. or lower. On the other hand, in the examples within the scope of the present invention without the sample number *, a dense sintered body can be obtained at a firing temperature of 1000 ° C. or less, and the relative dielectric constant is 5.5 or less. Characteristics with an f · Q value of 10,000 GHz or more can be obtained.

Further, FIG. 1 shows an X-ray diffraction pattern of the low-temperature fired ceramic composition (sample No. 7) using the first calcined powder calcined at 1100 ° C. As described above, the cordierite crystal peak is not confirmed in the pattern of the first calcined powder calcined at 1100 ° C. (see FIG. 2), but the cordierite in the structure after calcining at 950 ° C. Light was precipitated, and it was possible to obtain dense characteristics with a relative dielectric constant of 5.5 or less and an f · Q value of 10,000 GHz or more.

  Since the low-temperature fired ceramic composition of the present invention is a material that can be sintered at a low temperature of 1000 ° C. or lower, further 900 ° C. or lower, it is simultaneously fired with an electrode material such as silver, gold, or copper to form a laminated circuit board. Can do. Moreover, since it is a material having a low relative dielectric constant (ε5.5 or less) and a high f · Q value (f · Q10000 GHz or more), it can be applied to a laminated circuit board for high frequency.

It is a figure which shows the X-ray-diffraction pattern of the low-temperature baking ceramic composition which concerns on one Example of this invention. Is a diagram illustrating _{MgO, Al 2 O 3, SiO} 2 ( composition _{MgO13.78wt%, Al 2 O 3 34.86wt} %, SiO 2 51.36wt%) the X-ray diffraction pattern of the composition was fired at 1100 ° C. . Is a diagram illustrating _{MgO, Al 2 O 3, SiO} 2 ( composition _{MgO13.78wt%, Al 2 O 3 34.86wt} %, SiO 2 51.36wt%) the X-ray diffraction pattern of the composition was calcined at 1300 ° C. .

Claims (4)

A low-temperature fired porcelain composition comprising cordierite (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) crystals in the structure,
The main component is composed of oxides of Mg, Al, and Si, and Mg, Al, and Si are converted to MgO, Al ₂ O ₃ , and SiO ₂ , respectively, and the total amount is 100% by weight. And 15 to 40% by weight in terms of Al ₂ O ₃ and 45 to 65% by weight in terms of SiO ₂ , containing Mg, Al, Si,
With respect to 100% by weight of the main component, 0.1 to 5% by weight of B in terms of B ₂ O ₃ , 0.1 to 5% by weight of Cu in terms of CuO, and 0.005 in terms of Mn ₃ O ₄ as subcomponents. Containing 1 to 10% by weight of Mn,
A low-temperature fired porcelain composition having a relative dielectric constant of 5.5 or less, an f · Q value of 10,000 GHz or more , a sintered density of 2.48 g / cm ³ or more, and produced by a heat treatment of less than 1200 ° C. 2. The composition according to claim 1, further comprising at least one kind of 0 to 10 wt% Bi in terms of Bi ₂ O ₃ and 0 to 2.5 wt% Zn in terms of ZnO as subcomponents. A low-temperature fired porcelain composition.   MgO, Al as the main ingredient ₂ O ₃ , SiO ₂ A first calcining step of calcining at a temperature of 900 ° C. or higher and lower than 1200 ° C .;
  In the first calcined powder obtained through the first calcining step, ₂ O ₃ , CuO, Mn ₃ O ₄ A second calcining step of calcining at a temperature lower than the firing temperature in the first calcining step at 700 ° C. or higher,
  A molding step using the second calcined powder obtained through the second calcining step as a molded body;
  Having a firing step of firing the molded body at a temperature higher than the firing temperature in the second calcining step;
  In the firing step, cordierite (2MgO.2Al ₂ O ₃ ・ 5SiO ₂ ) A method for producing a low-temperature fired porcelain composition characterized by precipitating crystals.   Bi as an additional component ₂ O ₃ At least one of ZnO and B ₂ O ₃ , CuO, Mn ₃ O ₄ The method for producing a low-temperature fired ceramic composition according to claim 3, wherein the first calcined powder is mixed together.

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