JPH05155656A - Ceramic composition for low temperature sintering for multilayered substrate - Google Patents

Abstract

PURPOSE:To provide a low-temp. sintering ceramic compsn. for a multilayered substrate which can be sintered at rather low temp. and has small coefft. of thermal expansion, small dielectric const., and that the changing rate of capacity on temp. can be easily controlled. CONSTITUTION:This low-temp. sintering ceramic compsn. for a multilayered substrate consists of 100 pts.wt. of the main component and 20 pts.wt. of TiO2 as subcomponent added thereto. The main component consists of 40-85wt.% cordierite, 10-40wt.% B2O3 and 5-50wt.% of SiO2.

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 porcelain composition for a multi-layer substrate, and particularly to a multi-layer substrate suitable for a multi-layer porcelain substrate in which a plurality of porcelain layers are laminated and a circuit is formed between porcelains. Relates to a low temperature sintered porcelain composition.

[0002]

2. Description of the Related Art In general, with the miniaturization of electronic equipment, a porcelain substrate has been widely used for mounting various electronic components constituting an electronic circuit. And recently, in order to further increase the packaging density, a multilayer substrate has been developed in which a plurality of unfinished porcelain sheets with circuit patterns formed on the surface with a paste of a conductive material are laminated and fired to be integrated. There is. Conventionally, alumina has been used as a material for such a multilayer substrate.

[0003]

However, since the sintering temperature of alumina is as high as 1500 to 1600 ° C., a large amount of energy required for sintering is required and the cost becomes high. Furthermore, the conductive material of the internal circuit formed inside the multilayer substrate is limited to refractory metals such as W and Mo that can withstand a high firing temperature, so that the resistance value of the circuit pattern itself becomes high. there were. Further, since the coefficient of thermal expansion of alumina is larger than that of the silicon chip that constitutes the semiconductor mounted on the alumina substrate, thermal stress is applied to the silicon chip, which causes cracks in the silicon chip. Further, since the dielectric constant of alumina itself is high, there is a problem that the delay time of a signal propagating inside the circuit becomes long.

In order to solve these problems, as disclosed in Japanese Patent Application Laid-Open No. 1-230462, cordierite-B ₂ O ₃ -SiO ₂ type materials have a small thermal expansion coefficient and a small dielectric constant. A low temperature porcelain composition for a multilayer substrate having a high specific resistance is provided.

On the other hand, LC using several M to several tens of MHz band
There is an increasing need for an R circuit built-in type multilayer substrate for mounting LSI. As a characteristic of this substrate, in addition to the above characteristics, it is necessary that the rate of temperature change of the capacitance is particularly low, for example, ± 30 ppm or less.

However, the above cordierite-B ₂ O _3-
SiO ₂ materials have a capacity temperature change rate of 90 ppm / ° C.
As described above, there are limitations in applying the above substrate material to a high frequency compatible 2CR built-in substrate.

Therefore, a main object of the present invention is a low temperature porcelain composition for a multilayer substrate which can be sintered at a relatively low temperature, has a small coefficient of thermal expansion, a small dielectric constant, and is easy to control the temperature change rate of capacitance. Is to provide.

[0008]

According to the present invention, a main component 10 comprising 40 to 85% by weight of cordierite, 10 to 40% by weight of B ₂ O ₃ and 5 to 50% by weight of SiO ₂ is used.
This is a low temperature sintered porcelain composition for a multilayer substrate, in which 20 parts by weight or less of TiO ₂ is added as an accessory component to 0 parts by weight.

[0009]

FUNCTION TiO ₂ is a material having a negative temperature coefficient, and the absolute value of the temperature coefficient becomes small by adding and co-firing a cordierite-B ₂ O ₃ -SiO ₂ based material.

[0010]

According to the present invention, it is possible to sinter at a relatively low temperature, the coefficient of thermal expansion is small, the dielectric constant is small, and the temperature change rate of the capacitance can be easily controlled in a wider frequency band. A porcelain composition is obtained.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments with reference to the drawings.

[0012]

EXAMPLES First, Si which is a raw material of cordierite
O ₂ , MgO or MgCO ₃ , Al ₂ O ₃ were weighed and mixed to obtain a mixture. This mixture at 1350-1400 ° C
To obtain a cordierite calcined product having the composition shown in FIG.

Next, the cordierite raw material, B ₂ O ₃ , BN or B ₄ C and SiO ₂ which are other main component constituent materials, and TiO ₂ which is an additive constituent material are prepared, and Table 1 The mixture was weighed and mixed so that a porcelain having the composition shown in 1 was obtained.

[0014]

[Table 1]

Then, this mixture was calcined at a temperature of 800 to 900 ° C. and pulverized to obtain a powder. An organic binder was added to this powder and kneaded to obtain a slurry. The obtained slurry was formed into a sheet having a thickness of 1 mm by a doctor blade method to obtain a ceramic green sheet. This ceramic green sheet was cut into a size of 30 mm in length and 10 mm in width, and the binder component was heated at 900 ° C. in a nitrogen-steam reducing or non-oxidizing atmosphere using nitrogen passed through the steam as a carrier gas. Burning, Table 1
It was fired at each temperature shown in 1 hour for 1 hour to obtain a porcelain. In addition, the ceramic green sheet is cut into a rectangular plate having a length of 3 mm and a width of 40 mm, and the cut sheets are stacked to obtain 200 kg / cm.
^It was pressed with ² to form a prism having a size of about 4 mm × 3 mm × 40 mm. Then, this was fired by the above method to obtain a measurement sample for measuring the coefficient of thermal expansion, bending strength, and the like.

Table 1 shows the measurement results of each characteristic of each sample thus obtained. In addition, the amount of the additive in Table 1 is the cordierite-SiO ₂ -B ₂ which is the main component.
It is the amount added externally to the O ₃ system, and more specifically, it is the total amount of the solid solution in cordierite and the amount added in SiO ₂ —B ₂ O ₃ .

The relative dielectric constant is a value measured at a frequency of 1 MHz, and the specific resistance is a value when a direct current of 100 V is applied to the sample. The coefficient of linear thermal expansion α is a value calculated by the formula of α = {ΔL / L (T ₂ −T ₁ )} + αSiO ₂ . Here, ΔL is the apparent elongation (mm) of the sample due to heating, L is the length (mm) of the sample at room temperature, T ₁ is room temperature, T ₂ is 500 ° C., αSiO
₂ is the coefficient of thermal expansion of quartz glass. The bending strength is JI
It is a value measured according to the three-point bending method of S standard (R1601). The porosity is a value calculated from the density measured by the Archimedes method.

As shown in Table 1, the temperature change rate of the capacity can be easily controlled by changing the addition amount of TiO ₂ , and the temperature coefficient can be set to ± 30 ppm or less. Further, the composition of the present invention can be sintered at a relatively low temperature, has a small coefficient of thermal expansion, and has a small dielectric constant, which satisfies the conventional characteristics.

Cordierite is 2MgO.2A
l ₂ O ₃ .5SiO ₂ as well as the American Ceramic Society (TheAmerican Ceramic)
Society, Columbus,
1964, EN Levine et al.
t al. )) Phase diagram of ceramic (Phase Diagrams for Ceram)
ic), P246, and the composition range disclosed in FIG. 712, and more specifically, the region A in FIG. FIG. 2 is a main component composition diagram showing the main component composition ratio of the composition of the present invention, and the region B is the range of the main component of the composition of the present invention.

The reason for limiting the composition range as described above is as follows.

That is, when the cordierite content is less than 40% by weight, the mechanical strength is low, while when it exceeds 85% by weight, the sintering temperature is high. Also, B ₂ O ₃ is 10% by weight
If it is less than 40%, the sintering temperature becomes high, while if it exceeds 40% by weight, it becomes porous and the mechanical strength becomes low.

When the content of TiO _{2 as an} additive exceeds 20 parts by weight with respect to 100 parts by weight of the main component, the sintering temperature becomes high when the main component is cordierite-rich, and B ₂ O ₃ is added.
In the —SiO ₂ rich system, the mechanical strength is low, and in any case, the specific resistance is low and the dielectric constant is high.

[Brief description of drawings]

FIG. 1 is a composition diagram showing a composition ratio of cordierite.

FIG. 2 is a main component composition diagram showing a main component composition ratio of the composition of the present invention.

Claims (1)

[Claims] 1. Cordierite is 40 to 85% by weight, B ₂ O ₃ is 10 to 40% by weight, and SiO ₂ is 5 to 5%.
A low temperature sintered porcelain composition for a multilayer substrate, wherein 20 parts by weight or less of TiO ₂ is added as an accessory component to 100 parts by weight of a main component of 0% by weight.