JP2002029841A - Low temperature sintering dielectric material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low temperature sintering dielectric material which can be calcined at <=1000 deg.C and shows low dielectric loss in a high frequency region. SOLUTION: The material consists of 60 to 100 vol.% crystalline glass powder and 0 to 40 vol.% ceramic powder and has such property that the material has 95 to 100 vol.% crystal phase and 0 to 5 vol.% glass phase after calcination.

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 material which is used for producing wiring boards and circuit parts and can be sintered at a low temperature of 1000.degree.

[0002]

2. Description of the Related Art Alumina ceramic, which has been widely used as a dielectric material for wiring boards and circuit parts, has a high firing temperature of 1600 ° C., and only high-melting metals such as molybdenum and tungsten can be used as internal conductor materials that can be simultaneously fired. It is. These metals have the disadvantage that the conductor resistance is high and the transmission loss increases.

[0003] Therefore, a glass ceramic material that can be fired at a temperature of 1000 ° C or less has been developed and put into practical use.
This glass-ceramic material is composed of a glass powder and a ceramic powder, and can be fired at a temperature of 1000 ° C. or less. Therefore, there is an advantage that silver or copper with low conductor loss can be used as the internal conductor.

[0004]

A high frequency circuit component material is required to have a low dielectric loss in the frequency band. However, conventionally known glass ceramic materials have a drawback that the dielectric loss in a high frequency range of 0.1 GHz or higher is as high as 20 to 50 ^-4, and high performance high frequency circuit components and dielectric filters are used by using this. Cannot be manufactured.

An object of the present invention is to provide a low-temperature sintered dielectric material which can be fired at a temperature of 1000 ° C. or less and has a low dielectric loss in a high frequency range.

[0006]

As a result of various experiments, the present inventor has found that the smaller the ratio of the residual glass phase after firing, the lower the dielectric loss in a high frequency range, and proposes the present invention. Reached.

That is, the low-temperature sintered dielectric material of the present invention comprises, by volume, 60 to 100% of a crystalline glass powder and 0 to 40% by volume of a ceramic powder.
It is characterized in that it has a property of 100% by volume and a glass phase of 0 to 5% by volume.

[0008]

The low-temperature sintering dielectric material of the present invention is made of crystalline glass powder, contains 40% by volume or less of ceramic powder if necessary, and can be fired at a temperature of 1000 ° C. or less. The amount of ceramic powder added was 40% by volume.
If it exceeds 300, the sintered body is not densified, the number of internal pores increases, and the insulating property decreases.

When crystalline glass is fired, it reacts with the inside of the glass or with ceramic powder to precipitate crystals.
For example, if a SiO ₂ —CaO—ZnO-based glass and alumina powder are used, a sintered body having high strength and low dielectric loss, in which anorthite crystals and garnet crystals are precipitated, can be obtained. When a SiO ₂ —MgO—CaO-based glass and forsterite powder are used, a sintered body having high expansion and low dielectric loss, in which forsterite crystals and wollastonite crystals are precipitated, can be obtained. If a SiO ₂ —TiO ₂ —Nd ₂ O ₃ -based glass and alumina powder are used, a sintered body having a high dielectric constant and a low dielectric loss, in which neodymium titanate crystals are precipitated, can be obtained. When a SiO ₂ —CaO—MgO—Al ₂ O ₃ system glass is used, a sintered body having a low dielectric constant and a low dielectric loss in which diopside crystals are precipitated can be obtained.

Further, in the present invention, the reason that the ratio of the crystal phase and the glass phase after firing is limited as described above is that when the glass phase exceeds 5% by volume, the dielectric loss becomes large at a high frequency of 0.1 GHz or more. This is not preferred. In order to reduce the ratio of the glass phase, for example, the composition of the crystalline glass to be used may be close to the theoretical value of the precipitated crystal.

The proportion of the crystal phase specified in the present invention refers to the precipitated crystal precipitated from the inside of the glass during firing, the precipitated crystal formed by the reaction between the glass powder and the ceramic powder, and the ceramic powder remaining without reacting. Shows the total amount of

[0012]

The present invention will be described below based on examples and comparative examples.

Table 1 shows examples of the present invention (samples No. 1 to No. 1).
4) and Table 2 show comparative examples (samples Nos. 5 to 8), respectively.

[0014]

[Table 1]

[0015]

[Table 2]

Each sample was prepared as follows. First, a glass raw material was prepared so as to have the composition shown in the table, put in a platinum crucible, melted at 1400 to 1500 ° C. for 3 to 6 hours, and then formed into a thin plate with a water-cooled roller. Next, after roughly pulverizing the molded product, water was added thereto and wet-pulverized by a ball mill to obtain a crystalline glass powder having an average particle size of 1.5 to 3 μm. Further, the sample No. Ceramic powders (average particle size: 2 μm) were added to 1-3, 5-7, to give mixed powders.

Next, a binder (polybutyl methacrylate), a plasticizer (butylbenzyl phthalate), and a solvent (toluene) are added to the sample powder, and the mixture is kneaded to form a slurry, which is formed into a green sheet having a thickness of 0.2 mm by a doctor blade method. Molded. Green sheet 6 further prepared
The sheets were laminated and pressed, degreased, and fired to obtain a dielectric. The firing temperature was such that the ink was applied to the sintered body fired at various temperatures and then wiped off so that no ink remained (=
The firing temperature of the sample fired at the lowest temperature among the samples (sintered densely) was described. In addition, about the obtained sintered body,
The precipitated crystal, the ratio of the crystal phase to the glass phase, the dielectric loss and the dielectric constant were evaluated. The results are shown in each table.

As can be seen from the table, each of the samples of the examples could be fired at a temperature of 1000 ° C. or less. At a frequency of 2.4 GHz, the dielectric constant was 6 to 25, and the dielectric loss was 3 to 10 × 10 ⁻⁴ .

On the other hand, each sample of the comparative example had a large ratio of the glass phase after firing, and thus had a large dielectric loss of 25 to 60 × 10 ⁻⁴ .

The precipitated crystal is obtained by pulverizing a sintered body,
It was identified by a line diffractometer. The ratio of the crystal phase to the glass phase was evaluated from the ratio of the halo height of the 100% glass phase.
The measurement of the dielectric constant and the dielectric loss was performed as follows. First, the raw material powder was press-molded into a size of 7 × 7 × 70 mm, and fired at 900 to 1000 ° C. to prepare a sample. Using this sample, measurement was performed at a measurement frequency of 2.4 GHz by a cavity resonator perturbation method.

[0021]

By using the low-temperature sintered dielectric material of the present invention, a dense sintered body can be obtained at a sintering temperature of 1000 ° C. or less, so that a multilayer ceramic device using silver and copper as inner conductors can be manufactured. . Moreover, since it has a low dielectric loss in a high frequency range of 0.1 GHz or more, it is suitable as a high frequency circuit component material.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01B 3/02 C04B 35/18 B

Claims (1)

[Claims] 1. A crystalline glass powder of 60 to 10% by volume.
A low-temperature sintered dielectric material comprising 0%, 0 to 40% by volume of a ceramic powder, and having a property that a crystal phase becomes 95 to 100% by volume and a glass phase becomes 0 to 5% by volume after firing.