JPH11302075A - Low temperature sintered dielectric porcelain composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low temp. sintered dielectric porcelain compsn. having a low dielectric constant, capable of ensuring a sufficient sintering density by low temp. sintering and used for electronic parts for a high frequency region. SOLUTION: The dielectric porcelain compsn. consists of 20-40 wt.% quartz and 60-80 wt.% borosilicate glass, this glass consists of 75-85 wt.% SiO2 , 14-20 wt.% B2 O3 and 1-5 wt.% K2 O, and 0.1-5 wt.% Al2 O3 based on the weight of the glass may further be added to the glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature sintered dielectric porcelain composition, and more specifically to a low-temperature sintered ceramic used for high-frequency multilayer ceramic substrates such as high-frequency multilayer inductors, capacitors and resonators. The present invention relates to a dielectric ceramic composition.

[0002]

BACKGROUND OF THE INVENTION Conventional multilayer ceramic substrates used for high-frequency devices such as multilayer inductors include a filler containing at least one of alumina, cordierite, mullite, forsterite, quartz and silica glass; What is composed of glass is used.

However, the conventional ceramic substrate composed of the above filler and glass has a dielectric constant of 5 to 5.
7, the material has a low self-resonance frequency to be used as a material for a high-frequency inductance, and the Q becomes insufficient in a high-frequency region. This has a problem that desired characteristics cannot be obtained when used as high-frequency electronic components. This becomes more pronounced as the frequency increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-mentioned problems, to reduce the dielectric loss with a low dielectric constant, and to further reduce the loss of Ag or Ag-.
Used in high-frequency multilayer ceramic substrates such as multilayer inductors, capacitors, and resonators used in high-frequency regions where sufficient sintering density can be obtained by low-temperature sintering that can be sintered together with low-resistance conductors such as Pd and Cu. An object of the present invention is to provide a low-temperature sintered dielectric ceramic composition.

[0005]

In order to achieve the above object, in the low-temperature sintered dielectric porcelain composition according to the present invention, quartz is 20 to 40% by weight, and borosilicate glass is 60 to 80 watts.
%. The components of the borosilicate glass is, _75～85Wt% as SiO _2, 14~20wt% as B 2 _{O 3,} comprising 1-5 wt% as _{K 2} O, and more _Al 2 _{O 3} relative to borosilicate glass 0.1-5wt
% Was added. Here, the upper limit and the lower limit of the range of each composition include the numerical value of each range described above. That is, "AB"
Means A or more and B or less.

[0006] Borosilicate glass significantly reduces Li and Na, which are factors that cause deterioration of dielectric loss, and contains an appropriate amount of K. Therefore, by adding such borosilicate glass to quartz, sintering can be performed at 900 ° C. or less with low loss and low dielectric constant. That is, if it is less than 60%, a sufficient sintered density cannot be obtained. Conversely, if more than 80% is added, softening deformation occurs. Therefore, the range is set to 60 to 80 wt%.

On the other hand, if the content of SiO ₂ is less than 75 wt%, the softening point of the glass is lowered, and the glass is softened and deformed when sintered with quartz, so that a desired shape cannot be obtained. Conversely, if more than 85 wt% is added, the softening point of the glass increases, and low-temperature sintering becomes impossible. That is, when sintered with quartz, a sufficient sintered density cannot be obtained. Therefore, the composition range of SiO _{2 and} the range of 75 to 85 wt% were set.

If the content of B ₂ O ₃ is less than 14% by weight, the softening point of the glass increases, and when sintered with quartz, a sufficient sintered density cannot be obtained. Conversely, B ₂ O ₃ is 20w
If it exceeds t%, the softening point of the glass decreases, and softening deformation occurs when the glass is sintered with quartz. Therefore, the composition range of B ₂ O _{3 is set to} a range of 14 to 20 wt%.

Further, K ₂ O is added to control the softening point of the glass and to improve the solubility. If the amount is outside the above range, that is, less than 1 wt% or more than 5%, the dielectric loss is deteriorated, and the main purpose of the present invention is to reduce the dielectric loss. Furthermore, when it is less than 1%, there is a problem that the softening point of the glass increases, and low-temperature sintering becomes impossible.

[0010] Al ₂ O ₃ is added to prevent cristobalite having a large thermal expansion coefficient from being precipitated from the glass during firing. However, since the dielectric constant of Al ₂ O ₃ is 9.7, an increase in the amount of addition increases the dielectric constant of the final sintered body, which hinders the reduction of the dielectric constant, which is the main object of the present invention. . And, specifically, when the content exceeds 5 wt% with respect to glass, the dielectric constant exceeds 4.5. Therefore, the upper limit is 5
wt%. Further, the addition amount of Al ₂ O ₃ is 0.1 wt.
%, The effect of preventing the precipitation of cristobalite from the glass cannot be exhibited. Then, Al
_The amount of ₂ O ₃ added to the glass was 0.1 to 5 wt%.

The borosilicate glass 3
It has been confirmed that a conventional glass to which ZnO, CaO, PbO, etc. are added in addition to the two components causes an increase in the dielectric constant or deterioration of the dielectric loss.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Borosilicate glass having an average particle size of 2.0 to 3.5 .mu.m and quartz having an average particle size of 0.6 to 0.8 .mu.m are mixed for 20 hours using a ball mill. The mixed powder obtained is dried. Next, PVA was added to the dried powder, and the powder was molded to a diameter of 14 mm and a thickness of 2 mm at a pressure of 300 MPa by powder molding. And
A sample was prepared by firing the molded article under the firing conditions of 900 ° C. for 1 hour.

Under the above conditions, the mixing ratio of quartz and borosilicate glass and SiO ₂ ,
A sample was prepared in which the composition ratio of B ₂ O ₃ and K ₂ O, and the amount of Al ₂ O ₃ added to the borosilicate glass were appropriately changed,
The dielectric constant and the dielectric loss were measured at 1 MHz for each using the capacitor method. As a result, experimental results as shown in Table 1 below were obtained.

[0014]

[Table 1]

[0015]

[Table 2] As is clear from the above table, Samples 2 to 6 were obtained by performing experiments by changing the mixing ratio of glass and quartz in increments of 10%. Sample 2 has a small amount of borosilicate glass, (Relative density) is not sufficient (80.8%). Sample 6
Has a large amount of borosilicate glass and causes softening deformation. Furthermore, the intermediate samples 3 to 5 had a low dielectric constant and a sufficient sintered density. Furthermore, as shown in Sample 9, when the mixing ratio of glass and quartz is 50:50 (the same as Sample 2), the sintering is also insufficient, and a material having desired characteristics cannot be produced. Similarly, when the mixing ratio of glass and quartz was 90:10 (the same as in Sample 6, the amount of glass was large) as in Sample 13, softening deformation occurred. From this result, it is understood that the ratio of quartz: borosilicate glass is preferably in the range of 20:80 to 40:60 (including each boundary value).

On the other hand, the sample 1 contains 12.1 wt% of B ₂ O ₃ .
%, The sintering was insufficient. Sample 7 is
Since B ₂ O ₃ was as large as 21.1 wt%, softening deformation occurred. Therefore, a defective product was obtained regardless of whether B ₂ O ₃ was large or small.

Sample 8 was insufficient in sintering because SiO ₂ was as large as 86.4 wt% and B ₂ O ₃ was as small as 11.1 wt%. Further, the sample 14 has a SiO ₂ content of 74.
As low as 4 wt%, B ₂ O ₃ is 23.1 wt%
Therefore, softening deformation occurred. Accordingly, defective products were obtained regardless of whether the amount of SiO ₂ was large or small.

In Sample 15, cristobalite was generated because Al ₂ O ₃ was 0, that is, no Al ₂ O ₃ was added. Sample 1
In No. 6, since the K ₂ O was as small as 0.5, the softening point of the glass increased, and sintering was insufficient even at 950 ° C., and it was confirmed that low-temperature sintering was impossible.

At other composition ratios, the dielectric constant was low, and sintering at a low temperature of 900 ° C. was confirmed.
A specific range of the composition ratio of the borosilicate glass is a region surrounded by hatching shown in FIG.

[0020]

As described above, the low-temperature sintered dielectric ceramic composition according to the present invention has a low dielectric constant, a low dielectric loss, and a low-resistance conductor such as Ag, Ag-Pd, or Cu. Sufficient sintering density can be obtained by low-temperature sintering that can be integrally sintered. Therefore, it can be effectively used as a multilayer ceramic substrate for high frequency such as a laminated inductor, a capacitor, and a resonator used in a high frequency region.

[Brief description of the drawings]

FIG. 1 is a view showing a composition range of a borosilicate glass used in the present invention.

Claims (1)

[Claims] 1. Quartz comprises 20 to 40% by weight, borosilicate glass comprises 60 to 80% by weight, and the component of the borosilicate glass is 75 to 85 as SiO _{2.
wt%, 14~20wt%} as B 2 _{O 3,} comprising 1-5 wt% as _{K 2} O, and more _Al 2 _{O 3,} characterized in that it is added 0.1-5 wt% relative to borosilicate glass Low temperature sintered dielectric porcelain composition.