JP2003221277A - Glass powder for forming dielectric, glass-ceramics composition for forming dielectric and dielectric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for forming dielectrics which can obtain a dielectric with small temperature dependency of a specific dielectric constant by burning at a temperature of 950°C or lower. <P>SOLUTION: A glass powder for forming dielectrics essentially comprises 1-45 mol% SiO<SB>2</SB>, 31-50 mol% TiO<SB>2</SB>, 10-40 mol% MgO+CaO+SrO+BaO and 0-15 mol% Al<SB>2</SB>O<SB>3</SB>. The glass powder for forming dielectrics containes 20-43 mol% SiO<SB>2</SB>, 25-50 mol% TiO<SB>2</SB>, 0-25 mol% CaO and 12-40 mol% SrO+BaO and has a ratio of ≥1 TiO<SB>2</SB>/SiO<SB>2</SB>. The dielectric is produced by burning the glass powder for forming dielectric in the range of 800-950°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass powder for forming a dielectric material that can be fired at a low temperature, a dielectric material produced by the low temperature firing, and the like.

[0002]

2. Description of the Related Art Dielectric materials having a relative dielectric constant of 15 to 40 are used for mobile phones, antennas for wireless LANs, resonance filters and the like. An antenna, a resonance filter, and the like are required to have a small change in resonance frequency with temperature. Therefore, the dielectric material is required to have a small temperature dependence of its relative permittivity. Conventionally, as such a dielectric material, CaT
For example, one obtained by firing iO ₃ —MgTiO ₃ ceramics at a high temperature of 1200 ° C. or higher is used.

Firing of the above-mentioned dielectric is carried out by silver (melting point: 962
(.Degree. C.) is required to be performed at the same time as the firing of the silver paste, which is performed to form an electrode or the like. However, while the silver paste is fired at 950 ° C. or lower, the CaTiO ₃ —MgTiO ₃ -based ceramics must be fired at 1200 ° C. or higher. That is, there is a problem that these cannot be fired at the same time.

For the purpose of solving such a problem, a SiO ₂ —TiO ₂ —RO glass powder (RO: alkaline earth metal oxide) containing 16 to 33% by weight of a lanthanoid oxide is disclosed. Have been (for example,
See Patent Document 1. ).

[0005]

[Patent Document 1] Japanese Unexamined Patent Publication No. 8-73239 (Table 1)

[0006]

The object of the invention is to be Solved by the _SiO 2 -TiO
_{The 2-} RO glass powder contains a lanthanoid oxide in a relatively high proportion. However, the lanthanoid oxide has a problem that it is generally expensive as an industrial raw material,
It is required to reduce the content ratio. An object of the present invention is to provide a glass powder for forming a dielectric, a glass-ceramic composition for forming a dielectric, and a dielectric that can solve such problems.

[0007]

Means for Solving the Problems The present invention provides SiO _{2 of 1 to} 45% and TiO ₂ 3 in terms of mol% based on the following oxides.
1-50%, MgO + CaO + SrO + BaO 10-
40%, Al ₂ O _{3 0 to} 15%, and essentially no lanthanoid oxide, or the same oxide in a range of less than 5% in terms of mass percentage. A forming glass powder is provided.

Further, the content expressed in mol% is SiO ₂ 2
0-43%, TiO ₂ 25-50%, CaO 0-2
5%, SrO + BaO 12~40% , and _TiO 2 /
Provided is the dielectric-forming glass powder having SiO ₂ of 1 or more. Further, the content of SrO is 0 to 7 mol%, does not contain an alkali metal oxide, or contains the same oxide in a total amount of 1 mol% or less, the glass for forming a dielectric material. Provide a powder.

Also, the glass powder for forming the dielectric is 80
Provided is a dielectric material obtained by firing in the range of 0 to 950 ° C. Further, the temperature change rate (df / dT) / f of the resonance frequency f at a temperature T of −25 to 85 ° C. is −50 to 50 p.
Providing the dielectric as pm / ° C.

Also provided is a glass-ceramic composition for forming a dielectric containing the above-mentioned dielectric-forming glass powder and a ceramic powder, wherein the content of the ceramic powder is 30% or less. Further, there is provided a dielectric material obtained by firing the glass-ceramic composition for forming a dielectric material in a range of 800 to 950 ° C.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The dielectric-forming glass powder of the present invention (hereinafter referred to as the glass powder of the present invention) or the dielectric-forming glass ceramic composition of the present invention (hereinafter referred to as the glass-ceramic composition of the present invention). .) Is used in the manufacture of dielectrics having a relative permittivity of typically 15-40. That is, the glass powder of the present invention or the glass ceramic composition of the present invention is usually fired at a temperature of 950 ° C. or lower to obtain a fired body.

[0012] The firing is typically 850 to 950 ° C.
For 5 to 120 minutes or 5 to 180 minutes, more typically 900 ° C or 860 to 910 ° C for 60 minutes. The fired body obtained by firing the glass powder of the present invention or the glass ceramic composition of the present invention at a temperature of 950 ° C. or lower is hereinafter referred to as main fired body. When the temperature is 800 ° C. or higher, the fired body is the dielectric material of the present invention. Therefore, the following description regarding the main fired body also applies to the dielectric body of the present invention.

The relative permittivity ε ₂₅ at 25 ° C. and 50 MHz of the fired body is preferably 15-40. 15
If it is less than the above value, the capacitor cannot be made small when used as a capacitor to be incorporated into the ceramic multilayer substrate, and as a result, it may be difficult to make the ceramic multilayer substrate into a small module, which has been strongly demanded in recent years. It is more preferably 18 or more, and particularly preferably 20 or more.

When ε ₂₅ exceeds 40, the wiring pattern (antenna circuit pattern) of the antenna to be formed on the antenna substrate when used as an antenna substrate may become too fine and it may be difficult to form the pattern. It is preferably 35 or less.

The temperature change rate τ _ε of the relative permittivity at 50 MHz of the fired body at −25 to 85 ° C. is −100 to 1
It is preferably 00 ppm. More preferably -3
It is 0 to 30 ppm. In the present specification, the relative permittivity is represented by ε and the temperature is represented by T, and (dε / dT) / ε _{25 is referred} to as a temperature change rate of the relative permittivity.

The average linear expansion coefficient α of the fired product at −25 to 85 ° C. is typically 8 to 10 ppm / ° C.

Resonance frequency f of the fired body is −25 to 85 ° C.
The temperature change rate τ _f (= (df / dT) / f) at −
It is preferably 50 to 50 ppm / ° C. Outside this range, it may be difficult to use it for an antenna, a resonance filter, or the like. More preferably -25 to 25 pp
m / ° C. Note that τ _f is the above τ _ε (unit: ppm
/ ° C.) and the above α (unit: ppm / ° C.). [tau] _f =-([tau] [ _epsilon] / 2)-[alpha].

Next, the glass powder of the present invention will be described. The mass average particle diameter D ₅₀ of the glass powder of the present invention is 30 μm.
It is preferably m or less. If it exceeds 30 μm, the softening flow of the glass powder during firing becomes smaller than the particle size of the glass powder, and it becomes difficult to obtain a flat or dense fired body.
More preferably 20 μm or less, further preferably 10 μm
m or less, particularly preferably 5 μm or less, most preferably 2.5 μm or less. Further, D ₅₀ is preferably 0.
It is 5 μm or more, more preferably 0.8 μm or more.

The glass powder of the present invention is preferably one in which crystals precipitate during firing. If the crystals do not precipitate during firing, problems such as reduction in strength of the main body may occur.

Τ of the main body_εBy reducing |
τ_fIf you want to reduce |, the crystal should be
Snow stone (Ba_TwoTiSi_TwoO₈Crystal), Sr_TwoTiSi
_TwoO ₈Selected from the group consisting of crystals and fresnolite crystals
One or more types of crystals (hereinafter referred to as Fresnolite type crystals)
U ) Is preferable. Fresnoite crystal here
Is Ba_TwoTiSi_TwoO₈Crystal, Sr_TwoTiSi_TwoO
₈Crystal and Ca_TwoTiSi_TwoO₈From the group of crystals
A composition corresponding to a composition obtained by mixing two or more selected crystals
Refers to a crystal having

When it is desired to increase ε ₂₅ of the fired body, the crystal is one or more selected from the group consisting of CaTiO ₃ crystal, SrTiO ₃ crystal, BaTiO ₃ crystal and perovskite type crystal (hereinafter , And perovskite type crystals).

Next, the composition of the glass powder of the present invention
The mol% will be simply described as%. The mol% display group
The oxide used as the basis for calculation is the one with the lowest valence.
It For example, Pr oxide contains three types of oxides, Pr.
O_Two, Pr_TwoO_ThreeAnd Pr₆O ₁₁There is a book
When the glass powder of the invention contains Pr, Pr is Pr
_TwoO_ThreeCalculate the mol% display composition as existing in the form of
To do.

SiO ₂ is a network former,
Required. If it is less than 1%, it does not vitrify. It is preferably at least 12%. When it is desired to precipitate fresnolite type crystals during firing, the content is preferably 20% or more, more preferably 22% or more.

If the SiO ₂ content exceeds 45%, the softening point of the glass will be high, and the sinterability will decrease when fired at a temperature of 950 ° C. or lower, and crystals will not easily precipitate when fired at a temperature of 950 ° C. or lower. Or the ε _{25 of the} fired body becomes too small. Preferably 43% or less, more preferably 40
% Or less, particularly preferably 34% or less, most preferably 3% or less.
It is 2% or less.

TiO ₂ stabilizes the glass, ε ₂₅
Is increased or the absolute value of τ _ε is decreased, which is essential. It is also a constituent component of crystals such as Fresnoite type crystals, and is essential when it is desired to precipitate Fresnosite type crystals during firing. TiO ₂ is preferably 35
% Or more. Further, if it exceeds 50%, the glass becomes rather unstable. It is preferably 45% or less.

[0026] of TiO ₂ and SiO ₂ molar ratio of _TiO 2 / S
It is preferable that iO ₂ is 1 or more. Ε is less than 1
₂₅ becomes small, or when it is desired to precipitate crystals such as Fresnoite type during firing, the precipitation amount becomes insufficient and τ _ε
May increase. It is more preferably 1.1 or more.

MgO, CaO, SrO and BaO have the effect of stabilizing the glass or reducing the absolute value of τ _ε and must contain at least one of them. If the total content of MgO, CaO, SrO and BaO MgO + CaO + SrO + BaO is less than 10%, the glass becomes unstable. It is preferably at least 31%. Four
If it exceeds 0%, the glass becomes rather unstable.

When it is desired to deposit fresnolite type crystals or perovskite type crystals during firing, or to stabilize glass, CaO, SrO and BaO are used.
It is preferable to contain any one or more of the above. When it is desired to precipitate both fresnolite type crystals and perovskite type crystals during firing, it is preferable to contain any two or more of CaO, SrO and BaO.

When it is desired to increase ε ₂₅ , S
It is preferable to contain either one of rO and BaO, and the total content S of SrO and BaO at this time S
It is more preferable that rO + BaO is 12 to 40%. If it is less than 12%, ε ₂₅ may be small. It is more preferably 14% or more, and particularly preferably 15% or more. If it exceeds 40%, the glass may become unstable.
It is more preferably 29% or less.

When SrO is contained, its content is 7%.
The following is preferable. If it exceeds 7%, the glass may become unstable. It is more preferably 2% or less.

When it is desired to stabilize the glass, CaTiO
_When it is desired to precipitate ₃ crystals during firing, Ca
It is preferable to contain O in the range of up to 25%. 25
If it exceeds%, ε ₂₅ tends to be small, or crystals such as Fresnoite type crystals may be hard to precipitate. More preferably 20%
It is the following. When CaO is contained, its content is preferably 1% or more, more preferably 2% or more.

Al ₂ O ₃ is not essential, but may be contained up to 15% for stabilizing the glass or the like. If it exceeds 15%, the softening point tends to be high. It is preferably 10% or less, more preferably 5% or less, particularly preferably less than 1%.

The glass of the present invention consists essentially of the above-mentioned components, but may contain other components for promoting the precipitation of crystals, coloring the glass, etc. within the range not impairing the object of the present invention. The total content of the other components is preferably 10% or less. If it exceeds 10%, the glass may become unstable. It is more preferably 5% or less.

As the other components, B_TwoO_Three, Z
nO, ZrO_Two, SnO, GeO_Two, TeO_Two, P_TwoO
₅, Y_TwoO_Three, Ga_TwoO_Three, In_TwoO_Three, Ta_TwoO₅,
Nb _TwoO₅, Mo_TwoO_Three, WO_Two, FeO, Sb
_TwoO_Three, Bi_TwoO_Three, MnO, Cu _TwoO, CoO, V
O, Cr_TwoO_ThreeIs exemplified.

The glass of the present invention comprises Li ₂ O, Na ₂ O and K.
_{Even if} the alkali metal oxide such as ₂ O is not contained or the alkali metal oxide is contained, the total content of the oxides is preferably 5% or less. If it exceeds 5%, the electrical insulation may be deteriorated. It is more preferably 3% or less, and particularly preferably 1% or less.

The glass of the present invention is La_TwoO_Three, Ce_TwoO,
Pr_TwoO_Three, Nd_TwoO_Three, Sm_TwoO _ThreeLanthanoids, etc.
Containing no lanthanide oxide
Even if it is contained, the total content of the oxides is the mass.
The percentage is 5% or less. Preferably 1% or less
It

Next, the glass-ceramic composition of the present invention will be described with reference to the percentage by mass. The glass powder of the present invention is an essential component. The content is preferably 70% or more. If it is less than 70%, the denseness of the fired product may be reduced.

The ceramic powder is an essential component for adjusting the dielectric constant of the main body by, for example, increasing it. If it exceeds 30%, the denseness of the main fired product will decrease. It is preferably 10% or less. Moreover, the content is typically 5% or more.

As the ceramic powder, Al_TwoO_ThreeConclusion
Crystal, TiO_TwoCrystal, Ba_TwoTiSi _TwoO₈Crystal, Sr_Two
TiSi_TwoO₈Crystal, CaTiO_ThreeCrystal, BaTiO_Three
Crystal, BaTi_FourO₉Powders such as crystals are exemplified.

Next, the dielectric material of the present invention will be described.
The dielectric material of the present invention preferably contains a Fresnoite type crystal when it is desired to reduce τ _ε . Further, when it is desired to increase ε ₂₅ , it is preferable to contain a perovskite type crystal.

The dielectric material of the present invention is manufactured, for example, by the green sheet method. That is, the glass powder of the present invention or the glass ceramic composition of the present invention, a resin such as polyvinyl butyral or an acrylic resin, a solvent such as toluene, xylene, butanol, and further dibutyl phthalate, dioctyl phthalate, phthalic acid if necessary. Add a plasticizer such as butylbenzyl to make a slurry. This slurry is formed into a sheet on a film such as polyethylene terephthalate (PET) by a method such as a doctor blade method and dried to remove the solvent to obtain a green sheet. The green sheet is fired at 800 to 950 ° C. to obtain a thin plate-shaped dielectric.

[0042]

[Examples] Raw materials were mixed and mixed so that the composition shown in mol% in the column of SiO _{2 to} ZrO _{2 in} the table was mixed, and the mixed raw materials were put into a platinum crucible and melted at 1400 ° C. for 60 minutes. The molten glass was poured out and cooled. The obtained glass was crushed with an alumina ball mill for 30 hours to prepare glass powder. Examples 1 to 6 are examples and Example 7 is a comparative example.

D of glass powder measured by using a laser diffraction particle size analyzer (SALD2100 manufactured by Shimadzu Corporation)
₅₀ is shown in the table (unit: μm).

The sinterability of the glass powders of Examples 1 to 7 was examined as follows. That is, 2 g of glass powder was used for a diameter of 12.
It was pressure-molded into a column of 7 mm, and was held at 900 ° C. for 60 minutes, and the obtained fired body was immersed in a red penetrant (Super Check UP-G3 manufactured by Marktec Co., Ltd.) and washed with water.
It was observed whether or not the fired body was colored red. As a result, none of the fired bodies of the glass powders of Examples 1 to 7 was colored red and the sinterability was good, that is, the denseness of these fired bodies was good.

40 g of each glass powder of Examples 1, 2, and 7
Was placed in a mold of 60 mm × 60 mm and pressure-molded, and this was held at 900 ° C. for 60 minutes and baked. The upper and lower surfaces of the obtained fired body were ground and polished to obtain a sample having a thickness of 1.5 mm. This sample was placed in a constant temperature bath set at a temperature of 25 ° C., and an impedance analyzer (HP4291A manufactured by Hewlett-Packard Co.) was used at 15 ° C.
The relative dielectric constant ε ₂₅ at 50 MHz was measured.

With respect to the glass powders of Examples 1 to 7, ε ₂₅ was measured first except that the relative dielectric constant was measured every 1 minute while lowering the temperature from 85 ° C. to -25 ° C. at a rate of 1 ° C./min. The relative permittivity at 50 MHz was measured in the same manner as described above. The temperature change data ε _T (T:
From -25 to 85 ° C) and obtain the linear regression calculation coefficient
_It was divided by ₂₅ to obtain τ _ε (unit: ppm / ° C).

The glass powders of Examples 1 to 7 were heated to 900 ° C. for 60 minutes.
5mm diameter and length
Processed into a rod of 20 mm and the average line at -25 to 85 ° C
The expansion coefficient α (unit: ppm / ° C) was measured. The result
τ_εAnd τ calculated from α _f(Unit: ppm / ° C)
Both are shown in the table.

For reference, a glass having the same composition as the glass powder of Example 2 was melted in the same manner as in Example 2, poured out and molded into a plate shape. Ε ₂₅ , α of the obtained plate glass,
τ _ε is 14.25, 8.7 ppm / ° C, +1 respectively
It was 09 ppm / ° C. Therefore, τ _f is −63.
It was 2 ppm / ° C.

Further, each glass powder of Examples 1 to 7 was treated at 900 ° C.
CuKα for the fired body obtained by holding it for 60 minutes
The presence or absence of crystal precipitation was confirmed by a powder X-ray diffraction method in the range of 2θ of 10 to 60 ° using a line. As a result, diffraction peaks of Fresnoite type crystals were observed in all the fired bodies. That is, in Examples 1, 2, 3, 4, and 6, Ba
The diffraction peak, which is slightly shifted from the diffraction peak position of the ₂ TiSi ₂ O ₈ crystal, but substantially coincides with it, is B in Example 5.
The diffraction peak of the a ₂ TiSi ₂ O ₈ crystal was Sr in Example 7.
Diffraction peaks of the ₂ TiSi ₂ O ₈ crystal were observed.

When the diffraction peaks having the highest intensity are arranged in descending order, the diffraction peak wavelengths are displayed in angstrom units.
3.04, 3.23, for Example 2, 3.01, 3.
22, 2.64, 2.99, 3.1 for Example 7.
It was 9, 2.90.

In Examples 1 to 6, d = 2.5 to
Diffraction peaks of perovskite-type crystals were observed around 2.6 angstroms.

[0052]

[Table 1]

[0053]

According to the present invention, ε is large, and ε
It is possible to obtain a dielectric having a low temperature dependence of 950 ° C. by firing at 950 ° C. or less, and it is possible to perform firing at the same time with a silver paste for forming a silver electrode. Further, the capacitor of the ceramic multilayer substrate incorporating the capacitor can be made small, and as a result, the ceramic multilayer substrate can be miniaturized. Also,
It is possible to manufacture an antenna, a resonance filter, or the like in which the resonance frequency has a small temperature dependence.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoyuki Kobayashi             1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa             Asahi Glass Co., Ltd. F-term (reference) 4G030 AA07 AA08 AA09 AA16 AA17                       AA36 AA37 BA09 GA27                 4G031 AA03 AA04 AA05 AA06 AA11                       AA29 AA30 BA09 GA11                 5G303 AA01 AA02 AB06 AB11 AB15                       CA02 CA03 CB03 CB06 CB17                       CB30 CB32 CB35

Claims (7)

[Claims] 1. In terms of mol% based on the following oxides, SiO _{2 is 1 to} 45%, TiO _{2 is} 31 to 50%, MgO + CaO + SrO + BaO is 10 to 40%, and Al ₂ O _{3 is 0 to} 15%. A glass powder for forming a dielectric, which does not contain a lanthanoid oxide, or contains the oxide in a range of less than 5% in terms of mass percentage. 2. A mol% display content of SiO ₂ 20 to 4
_{3%, TiO 2 25~50%,} CaO 0~25%,
SrO + BaO 12~40%, and _TiO 2 / SiO
_2. The dielectric-forming glass powder according to claim 1, wherein ₂ is 1 or more. 3. The SrO content is 0 to 7 mol%, no alkali metal oxide is contained, or the same oxide is contained in a total amount of 1 mol% or less. Alternatively, the glass powder for forming a dielectric according to 2. 4. A dielectric obtained by firing the glass powder for forming a dielectric according to claim 1, 2 or 3 at a temperature in the range of 800 to 950 ° C. 5. A resonance frequency f at a temperature T of −25 to 85 ° C.
Temperature change rate (df / dT) / f at −50 to 50
The dielectric according to claim 4, which has a ppm / ° C. 6. A glass-ceramic composition for forming a dielectric material, which comprises the glass powder for forming a dielectric material according to claim 1, 2 or 3 and a ceramic powder, and the content of the ceramic powder is 30% or less. . 7. A dielectric obtained by firing the glass-ceramic composition for forming a dielectric according to claim 6 in the range of 800 to 950 ° C.