JP3381332B2 - High dielectric constant glass ceramic - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a high dielectric constant and a low dielectric loss, particularly at frequencies in the microwave region, specifically at frequencies of 0.1 GHz and above, and is suitable as a microwave circuit component material. It relates to glass ceramics.

[0002]

2. Description of the Related Art In the advanced information age, information transmission tends to be faster and higher in frequency. In mobile communication devices typified by car phones and personal radios, and new media devices typified by satellite broadcasting, satellite communication, CATV, etc., compactification of devices is being strongly promoted, and along with this, dielectric resonators, etc. There is also a strong demand for miniaturization of the microwave circuit element.

The size of the microwave circuit element is based on the wavelength of the electromagnetic wave used. The wavelength (λ) of the electromagnetic wave propagating through the dielectric having the relative permittivity (ε) is λ = λ ₀ / √ε, where λ ₀ is the wavelength in vacuum. The circuit element can be miniaturized in inverse proportion to the parallel root of ε, but when the dielectric constant of the element is large, electromagnetic wave energy is concentrated in the element, which also has an advantage of reducing electromagnetic wave leakage.

In view of the above circumstances, in recent years, various ceramics having a high dielectric constant at frequencies in the microwave region have been developed as circuit component materials.

Further, a material in which a resin is reinforced with glass fiber having a high dielectric constant at the above-mentioned frequency has been developed.
This is specifically disclosed in Japanese Patent No. 537.

[0006]

As the above-mentioned ceramic materials, BaO--TiO ₂ series ceramics, BaO--
Ln ₂ O ₃ (lanthanide oxide) -TiO ₂ ceramic, composite perovskite ceramic, ZrO ₂ -Ti
O ₂ —SnO ₂ series ceramics and the like are used, but materials made of these ceramics have basic characteristics such as permittivity, temperature coefficient of permittivity, and thermal expansion coefficient.
There is also a problem that these characteristics cannot be changed freely.

In addition, when these ceramics are formed into a sheet shape, a plurality of sheets are laminated and then fired to produce a laminated high frequency device or a circuit board, 12
Since it is necessary to fire at a temperature of 00 ° C or higher, silver or copper cannot be used as an electrode or a conductor material, and it is necessary to use an expensive material having higher heat resistance, resulting in higher material cost. .

Further, the above-mentioned material in which the resin is reinforced by the glass fiber is superior to ceramics in cutting, punching, etc., but at a frequency of 0.1 GHz or higher,
In order to obtain a dielectric constant of 10 or more, polyvinylidene fluoride (ε = 13) or cyano resin (ε = 16 to 2) is used instead of the epoxy resin which has been widely used for circuit boards.
It is necessary to use a resin having a high dielectric constant such as 0).
However, such resins are not suitable for high frequencies (especially 100M
The dielectric loss (tan δ) at HZ or higher) is high, and the performance is not good as a microwave circuit board material. Moreover, the circuit board using such a resin has a drawback that it is basically low in heat resistance.

An object of the present invention is that it has a high dielectric constant and a low dielectric loss at frequencies in the microwave region and can be fired at a low temperature, so that silver or copper can be used as an electrode or a conductor material. Moreover, it is to provide a material having high strength and good heat resistance, which is suitable as a microwave circuit component material.

[0010]

As a result of various experiments, the inventors of the present invention have found that when an element having a large atomic weight and a large electronic polarizability is contained as a glass component, a high dielectric constant is obtained at a frequency of 0.1 GHz or higher. It was found that a glass powder having a specific ratio is obtained, and such a glass powder prepared by mixing such a glass powder with a ceramic powder in a predetermined ratio and firing is a material that achieves the above object, and proposes the present invention. Came to do.

That is, the high dielectric constant glass-ceramic of the present invention comprises, in mol%, SiO ₂ 30 to 80%, CaO + B.
aO + SrO + PbO + Bi ₂ O ₃ + K ₂ O + TiO ₂ + T
eO ₂ + La ₂ O ₃ + WO ₃ 10-60%, Al ₂ O ₃ 0
_{~3%, B 2 O 3 0~5} %, Al 2 O 3 + B 2 O 3 + P 2 O 5
0-30%, ZrO ₂ + SnO ₂ + MgO + ZnO + C
uO + Nb ₂ O ₅ + Nd ₂ O ₃ + Li ₂ O + Na ₂ O 0.5
-30% content, at a frequency of 0.1 GHz or higher, 7.0
30 to 80% by volume of glass powder having the above dielectric constant,
Ceramic powder 20-70% by volume, 0.1GH
Dielectric constant of 10.0 or more and 40 × 10 at frequency of z or more
It is characterized by having a dielectric loss of ^-4 or less.

In the high dielectric constant glass ceramic of the present invention, the ceramic powder is Al ₂ O ₃ , ZnO.Al ₂ O ₃ ,
MgO-Al ₂ O ₃ based ceramics, ZrO ₂ · SiO ₂ , Z
rO ₂ -SnO ₂ based ceramic, 2ZnO · SnO _2, Z
One selected from the group of nO-TiO ₂ -based ceramics.
Rui or high strength ceramic powder of two or more, and / or
(Mg, Ca) TiO ₃ , TiO ₂ , Ba (Zr _0.5 Ti
_{0.5) O 3, SnO 2 ·} TiO 2, ZrTiO 4, BaO-
TiO ₂ based ceramic, ZrO ₂ -TiO ₂ -SnO ₂ based Se
Lamic, (Pb, Ca) ZrO ₃ , SrTiO ₃ , Zr
O ₂ , (Ba, Sr, Ca) (Ti, Zr) O ₃ , BaO
-Ln ₂ O ₃ -TiO ₂ ceramic, composite type perovsk
One or more selected from the group of ITO oxides
It is characterized by being made of a high dielectric constant ceramic powder .

[0013]

The high dielectric constant glass-ceramic of the present invention is 0.1
A glass powder having a dielectric constant of 7.0 or more and a ceramic powder at a frequency of GHZ or more, and 0.1 GHZ
Dielectric constant of 10.0 or more and 40 × 10 ^{-4 at the} above frequencies
It has the following dielectric loss, but by changing the composition of glass powder, the type of ceramic powder and their mixing ratio as appropriate, in addition to the dielectric constant and dielectric loss, various factors such as mechanical strength, coefficient of thermal expansion, firing conditions, etc. It is possible to change the characteristics.

Various glass ceramics prepared by mixing glass powder and ceramic powder and firing have been proposed in the past. For example, glass powder represented by borosilicate glass, alumina, cordierite,
Glass ceramics obtained by mixing ceramic powders such as mullite and α-quartz and firing at low temperature have been developed, but all of these glass ceramics have a low dielectric constant.

The glass powder in the present invention has a high dielectric constant, but besides this, the glass becomes unstable,
It is important to select the composition so that it does not deteriorate the flowability, the acid resistance, and the chemical resistance when it is made into a fine powder. Is preferably selected such that the dielectric loss is 40 × 10 ⁻⁴ or less.

Among the constituents of the glass powder in the present invention, SiO ₂ is a basic constituent for glass formation,
30 mol% or more is contained, but the content is 80 mol%
When it is more than the above, the meltability is deteriorated, the softening point is increased, and low-temperature firing becomes difficult, which is not preferable.

CaO, BaO, SrO, PbO, B
i ₂ O ₃ , K ₂ O, TiO ₂ , TeO ₂ , La ₂ O ₃ ,
A component such as WO ₃ has an action of increasing the relative dielectric constant of glass and is contained in an amount of 10 mol% or more. However, when the content is 60 mol% or more, it is difficult to obtain a stable glass, which is preferable. Absent.

Further, components such as Al ₂ O ₃ , B ₂ O ₃ and P ₂ O ₅ have a function of assisting glass formation, but when the content thereof is 30 mol% or more, the ratio of glass is It is not preferable because the dielectric constant becomes low.

Further, ZrO ₂ , SnO ₂ , MgO, ZnO,
_{CuO, Nb 2 O 5, Nd} 2 O 3, Li 2 O, components such Na ₂ O is or preventing the devitrification of the glass, has an effect of improving chemical durability, 0.5 Contains more than mol%
However, if the content is 30 mol% or more, it is difficult to obtain a stable glass, which is not preferable.

The ceramic powder in the present invention has the functions of enhancing the mechanical strength of the glass ceramic and adjusting the dielectric constant, the dielectric loss, the thermal expansion coefficient, and the temperature coefficient of the dielectric constant.

When a glass powder having an extremely high dielectric constant is used in the present invention, a glass ceramic having a sufficiently high dielectric constant can be obtained without using a ceramic powder having a particularly high dielectric constant. It is desirable to mix glass powder with ceramic powder having a large effect of increasing the mechanical strength of the glass ceramic, that is, so-called high-strength ceramic powder. The high-strength ceramic powder is a ceramic powder having a high elastic modulus and a high melting point, such as Al ₂ O ₃ , ZrO ₂ , SnO ₂ , and T.
30 or more selected from the group of iO ₂
The ceramic powder containing at least mol% has such characteristics. Specifically, Al ₂ O ₃ , ZnO.Al ₂
O ₃ , MgO-Al ₂ O ₃ system ceramic, ZrO ₂ ·
SiO _2, ZrO ₂ -SnO ₂ based ceramic, 2ZnO
· SnO _2, ZnO-TiO ₂ based ceramic can be used.

On the other hand, when glass powder having a not so high dielectric constant is used and it is necessary to further improve the dielectric constant, at a frequency of 0.1 GHZ or higher, a dielectric constant of 15.0 or higher and 40 × 10. ^-It is sufficient to use a ceramic powder having a dielectric loss of ^-4 or less. Specifically, (Mg, Ca) T
iO ₃ , TiO ₂ , Ba (Zr _0.5 Ti _0.5 ) O ₃ , S
nO ₂ · TiO ₂ , ZrTiO ₄ , BaO-TiO ₂ series ceramics, ZrO ₂ —TiO ₂ —SnO ₂ series ceramics, (Pb, Ca) ZrO ₃ , SrTiO ₃ , ZrO
₂ , (Ba, Sr, Ca) (Ti, Zr) O ₃ , BaO
It is possible to use —Ln ₂ O ₃ —TiO ₂ system ceramics and composite type perovskite oxides.

Needless to say, in the present invention, high strength ceramic powder and high dielectric constant ceramic powder can be used together.

The high dielectric constant glass-ceramic of the present invention comprises 30 to 80% by volume of glass powder and 20 to 7 of ceramic powder.
Although it is 0% by volume, if the glass powder is 30% by volume or less, a dense glass ceramic cannot be obtained by firing at a low temperature of 1050 ° C. or less, while if the glass powder is 80% by volume or more, it is sufficient. Mechanical strength cannot be obtained.

Further, the glass powder and the ceramic powder can have a small particle size (about 0.5 to 2 microns) as compared with the diameter of the glass fiber (about 7 to 10 microns). Glass-ceramic has extremely high homogeneity of dielectric constant as compared with a composite material composed of glass fiber and resin.

By the way, in the mounting method in recent years, the semiconductor element may be flip-chip mounted by bare. When such a mounting method causes a material having a large α-ray emission amount to be in contact with the semiconductor element, the semiconductor element is May cause a soft error.

Therefore, it is desirable that the glass powder and the ceramic powder used in the present invention are made of a raw material from which impurities such as U and Th that emit α rays are removed. In particular, ZrO ₂ and PbO raw materials are α rays. Since many of them emit extremely high amounts, it is necessary to remove impurities that emit α rays when using these raw materials.

[0028]

EXAMPLES The high dielectric constant glass ceramics of the present invention will be described in detail below with reference to examples.

Tables 1 and 2 show the compositions of the glass powder used in the examples of the present invention.

[0030]

[Table 1]

[0031]

[Table 2]

The glass samples in Tables 1 and 2 were prepared as follows.

First, as raw materials, pure silica powder, calcium carbonate, barium carbonate, strontium carbonate, low α ray type red lead, bismuth trioxide, potassium carbonate, titania, tellurium dioxide, lanthanum oxide, tungsten trioxide, alumina, boric acid. , Lead phosphate, low α ray type zirconia, niobium pentoxide, neodymium oxide, sodium carbonate were prepared, and each raw material was blended so as to have each composition in the table, and then placed in a platinum crucible to 1400 to 1500 ° C. After being melted for 6 to 10 hours, it was formed into a thin plate by a water-cooled roller. Next, this molded body was roughly crushed, and then alcohol was added and wet crushed by a ball mill to obtain a powder having an average particle size of 1.5 to 2 μm.

The glass powder thus obtained is 1 GHZ
At a frequency of 8.3 to 14.3 and a dielectric constant of 2.0 to 2
It had a dielectric loss of 0.0 × 10 ⁻⁴ .

Tables 3 and 4 show the ceramic powders used in the examples of the present invention.

[0036]

[Table 3]

[0037]

[Table 4]

In Tables 3 and 4, Al ₂ O _{3 of} sample k and sample r
The commercially available ZrO ₂ was used. Also, other ceramic powders, as raw materials, calcium carbonate, titania, barium carbonate, low α-ray type zirconia, tin oxide, zinc oxide, niobium pentoxide, low α-ray type litharge,
Calcium carbonate, strontium carbonate, alumina, magnesia, pure silica powder, neodymium oxide were prepared, each raw material was blended so that the ceramics shown in Tables 3 and 4 were added, and water was added and wet-mixed by a ball mill for 24 hours. After drying, it was fired under the firing conditions shown in the table, and the fired product was pulverized by a ball mill until the average particle size became 1.5 to 2.0 microns.

The ceramic powder thus obtained is 1G
At a frequency of HZ, a dielectric constant of 8.5 to 255.0 and a value of 0.
It had a dielectric loss of 5 to 38.0.

Tables 5 and 6 show glass ceramics prepared by mixing the glass powders of Tables 1 and 2 and the ceramic powders of Tables 3 and 4, respectively.

[0041]

[Table 5]

[0042]

[Table 6]

A method for producing a green sheet made of these glass ceramics, laminating a plurality of the green sheets and sintering them will be described below.

First, glass powder and ceramic powder are mixed in the ratios shown in the table, and then a predetermined amount of binder, plasticizer and solvent are added to prepare a slurry. As the binder, for example, polyvinyl butyral resin, methacrylic acid resin, etc., as the plasticizer, for example, dibutyl phthalate, etc., and as the solvent, for example, toluene, methyl ethyl ketone, etc. can be used.

Then, the above slurry is applied onto a polyester film by a doctor blade method to prepare a green sheet having a thickness of about 0.2 mm. After that, dry this green sheet, cut it to a predetermined size,
A through hole is formed by mechanical processing, and a low resistance metal material serving as a conductor or an electrode is printed on the surface of the through hole and the green sheet. Then, a plurality of such green sheets are laminated and integrated by thermocompression bonding.

The laminated green sheet thus obtained is heated to about 500 ° C. at a rate of about 3 ° C./minute and kept at this temperature for about 30 minutes to remove the organic substances in the green sheet. After that, the temperature is raised to the firing temperature in the table at a rate of about 10 ° C./min, and the temperature is maintained for the firing time for sintering.

As is clear from Tables 5 and 6, each glass ceramic of the examples can be fired at a low temperature of 850 to 1050 ° C., and at a frequency of 1 GHZ, 10.7 to 47.0.
And a dielectric loss of 1.5 to 30.0 × 10 ⁻⁴ . Moreover, the bending strength is as high as 1200 kg / cm ² or more, and the thermal expansion coefficient is 60.0 to 94.0 × 10 ^-7 / ° C.
Met.

The dielectric constant and the dielectric loss in the table were obtained at a temperature of 25 ° C. using an impedance analyzer. The thermal expansion coefficient was measured using a quartz push rod type dilatometer. The softening point was measured by the well-known fiber method, and the specific gravity was measured by the Archimedes method. Furthermore, the bending strength is 10 × 2 after firing the sample.
It was molded into a 0 × 2 mm plate column and measured by a three-point load measuring method.

In the embodiment, the example of the green sheet is given as the method for producing the glass ceramic of the present invention.
The present invention is not limited to this, and various methods generally used for manufacturing ceramics can be applied.

[0050]

As described above, the high dielectric constant glass-ceramic of the present invention has a high dielectric constant and a low dielectric loss at frequencies in the microwave region, has high heat resistance and mechanical strength, and is fired at a low temperature. And is suitable as a microwave circuit component material.

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-63-291307 (JP, A) JP-A-4-292460 (JP, A) JP-A-6-24795 (JP, A) JP-A-6- 211564 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C04B 35/00-35/22 C04B 35/42-35/51 C03C 1/00-14/00 H01B 3/00 -3/14

Claims (2)

(57) [Claims] 1. SiO ₂ 30 to 80% by mole%, C
aO + BaO + SrO + PbO + Bi ₂ O ₃ + K ₂ O + T
iO ₂ + TeO ₂ + La ₂ O ₃ + WO ₃ 10-60%, A
l ₂ O ₃ 0 to 3%, B ₂ O ₃ 0 to 5%, Al ₂ O ₃ + B _{2
O 3 + P 2 O 5 0~30} %, ZrO 2 + SnO 2 + MgO +
ZnO + CuO + Nb ₂ O ₅ + Nd ₂ O ₃ + Li ₂ O + Na ₂
Glass powder containing 0.5 to 30 % of O and having a dielectric constant of 7.0 or more at a frequency of 0.1 GHz or more 30 to 80
Consisting of 20% to 70% by volume of ceramic powder,
A high dielectric constant glass-ceramic having a dielectric constant of 10.0 or higher and a dielectric loss of 40 × 10 ⁻⁴ or lower at a frequency of 0.1 GHz or higher. 2. The ceramic powder is Al ₂ O ₃ , ZnO.
Al ₂ O ₃ , MgO-Al ₂ O ₃ based ceramics, ZrO ₂ ·
SiO _2, ZrO ₂ -SnO ₂ based ceramic, 2ZnO ·
SnO ₂ , selected from the group of ZnO-TiO ₂ based ceramics
One or more high-strength ceramic powders, and
And / or (Mg, Ca) TiO ₃ , TiO ₂ , Ba (Z
r _0.5 Ti _0.5 ) O ₃ , SnO ₂ · TiO ₂ , ZrTiO ₄ ,
BaO-TiO ₂ based ceramic, ZrO ₂ -TiO ₂ -S
nO ₂ type ceramic, (Pb, Ca) ZrO ₃ , SrTi
O ₃ , ZrO ₂ , (Ba, Sr, Ca) (Ti, Zr) O
_{3, BaO-Ln 2 O 3} -TiO 2 based ceramic, composite Bae
One or two selected from the group of rovskite oxides
The high-dielectric-constant glass ceramic according to claim 1, which is made of a high-dielectric-constant ceramic powder of at least one of the above.