JPS5936364B2 - Ceramic composition for electronic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic composition for electronic components, and particularly provides a composition that can constitute a ceramic having properties required as an insulating material and having excellent heat resistance. This is what I am trying to do.

Ceramics are widely used for supporting substrates and sealing members for integrated circuits and the like.

These often require heat resistance. As is well known, BeO and Al2O are used as heat-resistant ceramic materials.
3. There are forsterite, steatite, mullite, etc.

However, since BeO is toxic, its uses are extremely limited. Other materials also have advantages and disadvantages.
In particular, it had a drawback of not having very good heat resistance. The present invention provides a ceramic composition that eliminates these drawbacks, and also makes it possible to realize ceramics that are excellent in insulation resistance and dielectric loss in a high frequency range. The ceramic composition according to the present invention has a shirasu component of 1.5 to 12% by weight, an Al2O3 component or AIOOH component of 75 to 94% by weight, a MIO component of 0.8 to 3% by weight, a TiO2 component of 2.7 to 7% by weight, and a chinastone component of 1 to 3% by weight.
Of course, other components may be additionally introduced to further improve the properties of the ceramic. This uses whitebait as one of its main ingredients. As is well known, shirasu is a type of oxidized volcanic ejecta widely distributed around southern Kyushu, and is a grayish-white deposit. Its estimated physical stock is approximately 6 x 1010 tons, making it an extremely abundant and inexpensive resource. Generally, the Shirasu component contains approximately 7.5% by weight of SiO2 and 14% by weight of Al2O3 component.
% by weight, 3% by weight of Na2O, 2% by weight of 2O, 3.5% by weight of water, 1.5% by weight of CaO, and 2% by weight of Fe2O.
3 is considered to be 1% by weight. Until now, Shirasu has been used in hollow microspheres (balloons), abrasive materials, ceramic tiles, etc. The inventors have been conducting research on the use of shirasu as a ceramic material for electronic components. As a result, when mixed with the above-mentioned inorganic compounds and metal oxides and fired, it has extremely excellent heat resistance. It was discovered that ceramics with good insulation properties and dielectric loss can be obtained.
Furthermore, compared to conventional alumina porcelain, the sintering temperature is lower, making it extremely advantageous for weighing ceramics. By the way, the reason why the composition ratio of the components in the ceramic composition of the present invention is specified as described above is as follows.

If the whitebait component is less than 1.5% by weight, the firing temperature will be 1.
The temperature exceeds 500°C, making it unsuitable for mass production of ceramics.

If this amount exceeds 12% by weight, the firing temperature may be low, but the firing tends to cause vitrification, making it difficult to obtain dense ceramics with good thermal conductivity.
If the Al2O3 component is less than 75% by weight, dielectric loss in the high frequency range increases and mechanical strength also decreases, which is not preferable.

Moreover, when it exceeds 94% by weight, the firing temperature is increased to 1.
Not only does sintering become difficult when the temperature exceeds 400℃,
Various properties including dielectric properties deteriorate. M9
When the O component is less than 0.8% by weight, not only the dielectric loss in the high frequency region decreases, but also the heat resistance characteristics deteriorate. When it exceeds 3.0% by weight, dense ceramics cannot be obtained and water absorption increases. TiO2
When the content of the component is less than 2.7% by weight, dielectric loss increases, and when the content is more than 7% by weight, the heat resistance properties deteriorate.

If the chinastone component is less than 1% by weight, the effect of lowering the sintering temperature will be poor, and if it is more than 3% by weight, not only will the dielectric loss increase, but the heat resistance properties will also deteriorate.

Hereinafter, it will be specifically explained by giving examples.

First, whitebait powder with a particle size of about 1 to 3 μm, and powders of Al2O3 or AIOOH, TiO2, MfIO, and chinastone were prepared and mixed to have the composition ratios shown in Table 1.

Each of the above formulations was wet-mixed using a urethane-lined pot mill, the water was evaporated, and a length of 40 mm was mixed.
It was molded into a rectangular plate shape with a width of 20n) and a thickness of 3mm.

The pressure for molding was approximately 700 to 1000 kg/Cd. Each molded body was placed in an electric furnace equipped with a SiC heating element, raised to a temperature within the range of 1300 to 1400°C at a heating rate of 150°C/hour, and held for 2 hours to be fired. For sample 17, the firing temperature was 20 to 30 degrees higher than that.
℃ lower temperature. Silver electrodes were baked onto each of the obtained ceramics using a commonly used method. Various characteristics of each of the samples thus prepared were investigated, and the results are shown in Table 2.

The dielectric properties were investigated and the results are shown in Table 2. The dielectric properties include the dielectric constant (ε) and dielectric loss (Tanδ) at 1MHz.
) was measured. The insulation resistance value was measured by applying 500 V DC at 500°C. Regarding thermal shock resistance,
They were immersed in molten solder at 500°C, then taken out and dropped from a height of 40 crn onto an aluminum plate with a thickness of 3 nm, and evaluated by the number of breakages per 10 pieces. In the table, 3/IO means that 3 out of 10 were damaged. As is clear from the above table, according to the composition according to the present invention, the thermal shock resistance of the obtained ceramics is extremely good. Even if you drop it on the board,
No damage occurred.

However, compositions outside the scope of the present invention have poor thermal shock resistance. Further, according to the composition of the present invention, the dielectric property at 1 MHz is 7.0 to 8.4, ta
nδ is 0.7 to 5.0, and bending strength is 1750 to 5.0.
2420kg/Cd) Insulation resistance value is 4.7 x 109 ~
It is 7.0×101/Ω. It can be seen from this that it has excellent electrical properties as a ceramic for electronic components. In addition, when AIOOH is used as the alumina component as in sample 17, not only the various properties are good, but the sintering temperature can be further lowered by 20 to 30 degrees Celsius than when Al2O3 is used, which makes it easier for mass production. It is very effective to use AIOOH in

Claims (1)

[Claims] 1 Shirasu component 1.5-12% by weight, Al_2O_3 component or AlOOH component 75-94% by weight, MgO component 0.8-3% by weight, TiO_2 component 2.7-7% by weight
, and 1 to 3% by weight of a chinastone component.