JPS5924753B2 - porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxide ceramic composition suitable for forming an insulated circuit board capable of forming a capacitor. The present invention relates to porcelain that has properties required for manufacturing circuit boards such as ICs.

Insulating porcelain made of Al2O3, MgO, and SiO2 is already widely used for heat-resistant insulating parts such as IC boards and IC packages.

2. Description of the Related Art In recent years, as IC-related technology has made remarkable progress and the use of ICs in various circuits is increasing, substrates are required to have various characteristics different from those of the past. For example, in order to increase the density and reduce the cost of circuits, there is a need for circuit boards that are capable of forming capacitors with negative temperature coefficients, for example for the purpose of temperature compensation of oscillation circuits. However, in conventionally known phenol substrates, for example, Q is 5.
Since it has a low temperature coefficient of 0.00 or less and a temperature coefficient of 100 ppM or more, it is not suitable for the purpose. In addition, in the case of an alumina substrate, the Q value is 500 or more, and although it has excellent mechanical strength and heat resistance, it is not suitable for the purpose because the temperature coefficient of dielectric constant is +100 ppM or more. On the other hand, the board may be constructed using a conventional temperature-compensating capacitor material, but in this case, the Q is as high as 1000 or more, and the heating coefficient is also +100 to -
It can be freely selected between 4,700 ppM, but on the other hand, the mechanical strength and heat resistance strength are low, and the properties as a substrate material cannot be satisfied in terms of strength. Therefore, there is currently no ceramic composition that satisfies both the properties required for capacitors and the properties required for substrates. Therefore, the purpose of the present invention is to have a relatively low dielectric constant, high Q, high mechanical strength and heat resistance strength, and to be able to freely select the temperature coefficient of the dielectric constant between +100 and -2200 ppM. An object of the present invention is to provide a porcelain composition. The present invention to achieve the above object is based on Al (aluminum), B
r (strontium), Ti (titanium), Mg (magnesium), Si (silicon) are these compounds A
l2O3 (aluminum oxide), SrTiO3 (strontium titanate), MgO (magnesium oxide), S
Al2O3 in terms of iO2 (silicon oxide)
, SrTiO3, falls into the ternary diagram of MgO + SiO2,
Al2O396 weight? , SrTiO32% by weight, MgO
+SiO22 weight? Point A indicating the weight percentage of Al2O38O and SrTiO3lO weight? , point B showing MgO+SlO2lO wt%, Al2O34O wt%, SrTlO
3lO weight%, MgO+SiO25O weight? Point C showing
5 and Al2O34O weight? , MgO+SiO22 weight? , and the molar ratio of MgO and SiO2 is MgO/Si
This relates to a porcelain composition obtained by sintering a mixture of O2≧2 and SiO2 in a proportion of 0.5% by weight or more.

According to the present invention, although the dielectric constant is small, the Q is high, and the temperature coefficient of the dielectric constant is +100 to -2200 ppM, the mechanical strength and heat resistance strength are large, and the insulation resistance is also sufficiently high. We can provide porcelain.

Therefore, it becomes possible to form a capacitor on an IC circuit board or the like. Furthermore, it becomes possible to provide a capacitor with high strength. Examples of the present invention will be described below. First, Al2O3, MgO with a purity of 98% or more,
SlO2 and SrTiO3 were each prepared and weighed so as to have the compounding ratios shown in Tables 1 to 7.

Next, using a polyethylene pot and an alumina ball,
The materials of each composition were wet mixed. Then the mixture is dehydrated
After drying, it was pre-calcined at about 125°C for 3 hours, and then pulverized. Next, an organic binder was added. In order to obtain a sample for measuring electrical characteristics, the above mixture was poured into a disk with a diameter of 16 mm and a thickness of about 100 k9.
/d, and this molded body is heated to approximately 12 mm in an electric furnace.
Main firing was performed at 00 pressure C to 1650° C. for 3 hours.

Next, as shown in FIG. 1, silver paste is applied to both main surfaces of the final fired disc porcelain substrate 1, and baked at 760°C for 20 minutes to form electrodes 2 and 3, respectively. completed the sample. Thereafter, the relative permittivity εs, rate of change in dielectric constant muddyness, and insulation resistance of each sample were measured. On the other hand, in order to obtain a sample for measuring the anti-destructive strength, the above mixture was
7! L, width 20m77! , about 1 on a square plate with a thickness of 1 mm
The molded body was press-molded at 000 kg/d7, and this molded body was fired in an electric furnace at a temperature of about 1,200 C to 1,600 C1 for about 3 hours.

Next, the breaking strength is determined using a commercially available anti-deflection strength measuring device based on the principle described on page 413 of ``Ceramic Dielectric Engineering'' by Kiyoshi Okazaki, and the anti-destructive strength is calculated using the following formula. The bending strength was calculated. In addition, in order to obtain a sample for measuring heat resistance strength, the above mixture was subjected to final firing using a wet molding method.The substrate size was 60m7!1. ×60m TIL><0.6m
m, and heat the molded body in an electric furnace at approximately 120°C.
Main firing was performed at ~1650°C for about 6 hours.

Next, the sintered body was preheated to a predetermined temperature in an electric oven for 10 minutes, and the preheated sample was passed through a commercially available dead-flow soldering device (soldering temperature: 30°C). Samples that broke when immersed in solder were considered defective, and samples that did not break were impregnated with a fluorescent agent, and the presence or absence of cracks was examined using the fact that the fluorescent agent penetrated into the cracks. And such trial 1
Experiments were conducted by varying the preheating temperature using an electric oven.
Then, the preheat mudness was determined when all 20 specimens of a group of 20 specimens having the same composition did not break or crack at all. The difference between the solder vorticity (30'C) and the highest preheating vorticity that does not cause damage or cracks was defined as the maximum non-destructive temperature difference R. Tables 1 to 7 show the composition, firing temperature, and characteristics of various samples.

However, since the three types of samples formed for the test had the same compounding ratio, they were considered to be the same sample. Note that the relative permittivity ε and Q in these tables are the results of measurement at room temperature and a frequency of 1 MHz, and the temperature coefficient TC of the permittivity was determined by.

However, C2O has a capacity of 2'C, and C35 has a capacity of 85°C.
Capacity and ΔT are 85°C - 20°C - 65°C
It is. As mentioned above, R is the maximum non-destructive temperature difference. Although it is not listed in this table, all boards have DC 10
The resistance was approximately 107 MΩ. Also, Tables 1 to 7
The blending points shown in the table indicate blending points A, B, C, etc., and ABCs of the ternary diagram in FIG. 2. Further, Tables 1 to 5 show the characteristics of the products that belong to the present invention, and Tables 6 and 7 show the notes of the products that do not belong to the present invention. It should be noted that the characteristics not recorded in Tables 6 and 7 were not measured due to other defects. Figure 2 is the first
~ FIG. 7 is a ternary diagram showing the composition of representative samples shown in Table 7. The area within the straight line connecting points A, B, C, and D in this ternary diagram, that is, the area marked with diagonal lines, is the composition area according to the present invention. Next, the reason for limiting each component will be described.

Samples in Tables 1 to 5/F6. The samples in the shaded area in Figure 2 have a high Q and a high dielectric constant vorticity coefficient (T
C) can be freely selected, and the transverse rupture strength is 1400K9/ml.
As mentioned above, the non-destructive temperature difference (R) is 12'C or more, and it has characteristics that it can be used as a capacitor and as a substrate. In contrast, samples outside the scope of the present invention. /V). 50 and 51, that is, those shown in blending point (a) have extremely excellent mechanical strength and thermal strength, but the TC exceeds +100 ppM, which deviates from the desired properties. In addition, the blending points . As is clear, TC exceeds +100 ppM, which is against the purpose.

Blend points and N indicate cases where the Al2O3 content is less than the line connecting blending points D and C.

In this case, the sample in Table 7/F6.66, 67, 68, 6
As is clear from 9, the transverse rupture strength is 1400 kg/(71 or less, and the non-destructive vorticity difference (T) is 12'C or less.) When used as a substrate, mechanical breakage and cracks due to thermal shock may occur. There is a property. The second compounding point is (
MgO+SiO2) content is blending point D. ! : Indicates the case where the number is less than the line connecting 1A.

In this case, sample waterfalls 56, 57, 61 in Tables 6 and 7
, 62, 64, and 65, the Q is low and the TC moves sensitively to the epigenetic temperature, making it extremely unstable. Also Mg
When the molar ratio of O and SlO2 is MgO/SiO2 <2, sample taki 55, 60 in Table 6 and sample rot 70, table 7
B. As shown in Nos. 71, 73, and 74, the sintering width is narrow, resulting in poor sintering and making it extremely difficult to obtain a dense sintered body. The Q of the sintered body is also low, and the bending strength is also low.

Therefore, it is desirable that MgO/SiO2≧. Further, sample waterfall 72 in Table 7 shows a SiO2 content of 0.5 or less.

If the amount of SiO2 added is small, the sinterability will be poor, resulting in a low Q and a low transverse rupture strength. Therefore, in order to improve sinterability, it is desirable to mix 0.5% by weight or more of SiO2. Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments.
It is also deformable. For example, in the above embodiment, A
Although l2O3, SrTiO3, MgO, and SiO2 were used as starting materials, starting materials such as Al, Sr, Ti, Mg
, Si or their carbonates, hydroxides, acid salts, etc.
Al, Sr, Ti, Mg, Si are Al2O3, SrTi
Of course, it may be converted into O3, MgO, or SiO2 and included in the range specified in the present invention. Although it is difficult to accurately measure the composition of the completed porcelain according to the present invention, Al2O3, SrTiO3, MgO, Si
O2 is almost included in the ratio within the range surrounded by the straight line connecting points A, B, C, and D in FIG. Furthermore, it is of course possible to add other components to the extent that the objects and effects of the present invention are not impaired, and this also falls within the technical scope of the present invention.

Also, there is no problem in changing the manufacturing method of porcelain. Moreover, it can be used not only for substrates but also for capacitors with large mechanical strength.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a capacitor for investigating the electrical characteristics of a ceramic composition according to an embodiment of the present invention, and FIG.
It is a ternary diagram of l2O3, SrTiO3, MgO+SiO2. In addition, according to the symbols used in the drawings, 1 is a ceramic substrate,
2 and 3 are electrodes, and A, B, C, and D are points indicating the composition.

Claims (1)

[Claims] 1 Al, Sr, Ti, Mg, Si are these compounds Al_2O_3, SrTiO_3, MgO, SiO
Al_2O_3, SrTiO_
3. Al_2O in the ternary diagram of MgO+SiO_2
_396% by weight, SrTiO_32% by weight, MgO+S
Point A indicating iO_22% by weight, Al_2O_380% by weight, SrTiO_310% by weight, MgO+SiO_2
Point B indicating 10% by weight and Al_2O_340% by weight,
Point C showing SrTiO_310% by weight, MgO+SiO_250% by weight, Al_2O_340% by weight, SrT
It is included in the range surrounded by a straight line that sequentially connects point D indicating iO_358% by weight and MgO + SiO_22% by weight, and the molar ratio of MgO and SiO_2 is MgO/SiO_2.
≧2 and SiO_2 is 0.5% by weight
A porcelain composition made by sintering a mixture of proportions falling within the above range.