JPH0643270B2 - Low temperature sintered porcelain composition for multilayer substrate - Google Patents

Description

Description: (a) Field of Industrial Application This invention relates to a low temperature sintered porcelain composition for a multilayer substrate, and more particularly to a multilayer porcelain in which a plurality of porcelain layers are laminated and a circuit is formed between the porcelains. The present invention relates to a low temperature sintered porcelain composition for a multilayer substrate suitable for a substrate.

(b) Conventional Technology In general, with the miniaturization of electronic devices, a porcelain substrate is used as a substrate for mounting various electronic components that make up an electronic circuit.Recently, in order to further increase the packaging density, a conductive material A multilayer porcelain substrate has been developed in which a plurality of unfired porcelain sheets having a circuit pattern formed by a paste are laminated and fired to be integrated. Alumina has been conventionally used as this kind of multilayer ceramic substrate.

(c) Problems to be Solved by the Invention However, alumina has a sintering temperature of 1500 to 1
Since the temperature is as high as 600 ° C., a large amount of energy is required for sintering and the cost becomes high. Further, the conductive material of the internal circuit formed inside the 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. . Furthermore, since the coefficient of thermal expansion of alumina is larger than that of the silicon chip mounted on the surface of the alumina substrate, thermal stress is applied to the silicon chip, which causes cracks in the silicon chip. In addition, since the dielectric constant of alumina itself is relatively high, there is a problem that the delay time of a signal propagating inside the circuit increases.

An object of the present invention is to provide a low temperature sintered porcelain composition for a multilayer substrate which can be sintered at a low temperature.

Another object of the present invention is to provide a low temperature sintered porcelain composition for a multilayer substrate, which has a small thermal expansion coefficient, a small dielectric constant, a small dielectric loss and a high specific resistance.

(d) Means for Solving Problems The low temperature sintered porcelain composition for a multilayer substrate of the present invention comprises the following materials.

That is, cordierite is 50 to 95% by weight, B ₂ O
₃ is 5 to 20% by weight, and SiO ₂ is 1 to 46% by weight.

In addition, one or more kinds of oxides of nickel and / or copper are added and added to the main component in an amount of 15% by weight or less in terms of NiO and / or CuO.

The cordierite here is 2MgO.2A ₂
In addition to O ₃ .5SiO ₂ , ENLevin et a1. By “Pha
se Diagrams for Ceramists ", The American Ceramic So
ciety, Columbus, 1964, P.246 (Fig. 72). FIG. 1 shows the composition region of cordierite. In the figure, region A is the composition range of cordierite. However, in this cordierite, MgO-A is used as long as the characteristics are not impaired.
_A crystal structure (for example, mullite, forsterite, spinel, tridymite, etc.) in the composition region around the ₂ O ₃ —SiO ₂ type cordierite can be contained up to 20% by weight of the main component.

In addition, nickel and copper oxides are included in the above main component as 1
It can be included up to 5% by weight.

Further, in obtaining the low temperature sintered porcelain composition for a multilayer substrate according to the present invention, ordinary ceramics technology is applied. That is, cordierite and B (boron) oxides or compounds, and SiO ₂ powders are weighed and mixed at a predetermined ratio, the raw material mixture is calcined and then crushed, and a binder is added to this powder to form a slurry. Is produced, a ceramic green sheet is produced by a sheet forming method such as a doctor blade method, and a laminated body of the ceramic green sheets is sintered to obtain a multilayer porcelain substrate.
Therefore, according to the above process, since there is no vitrification process, binder removal during firing is easy and energy consumption is low.

Furthermore, a paste pattern containing a conductive material for forming a conductive pattern is formed on the ceramic green sheet formed by the above process by a method such as printing or coating. The firing atmosphere may be set according to the means of these conductive materials. As the conductive material, for example, C
u, Ag, Ag-Pd, Ni, etc., but Ag, Ag
-Pd may be fired in an oxidizing atmosphere, and Cu and Ni may be fired in a non-oxidizing atmosphere such as nitrogen.

When the substrate itself is manufactured using the low temperature sintered porcelain composition for a multilayer substrate of the present invention, raw materials are weighed and mixed, and the raw material mixture is calcined at 800 to 900 ° C. and then pulverized,
The powder may be kneaded with a binder, formed on a film, and then the obtained ceramic green sheet may be fired in an oxidizing atmosphere or a non-oxidizing or reducing atmosphere.

When manufacturing a multilayer circuit board, a circuit pattern is printed on a ceramic green sheet with a conductive paste made of a conductive material such as Ag, Ag-Pd, Cn, or Ni, and a plurality of them are laminated, It suffices to fire in an atmosphere suitable for the conductive paste. Cu or N as conductive material
When using a base metal such as i, it is preferable to perform firing in a non-oxidizing or reducing atmosphere in order to prevent the oxidation thereof. For example, a nitrogen-steam atmosphere (usually N ₂ 99.7 to 99.8%) in which a small amount of oxygen and hydrogen is contained by passing through steam using nitrogen as a carrier gas.
It is preferable to bake at 950 to 1020 ° C. It should be noted that a small amount of oxygen is contained so that the binder used for forming the ceramic green sheet is completely burned in the calcination stage and is removed without remaining as carbon.

(e) Example First, a raw material for cordierite was prepared. As raw materials, SiO ₂ , MgO or MgCO ₃ or talc (3MgO.4SiO ₂ .H ₂ O) and A ₂ O ₃ were weighed and mixed. This mixture was calcined at 1350-1400 ° C. Thus, the cordierite composition shown in FIG. 1 was already obtained. Further, this cordierite calcined product was crushed and newly prepared as a cordierite raw material.

Next, this cordierite raw material and other constituent materials,
That is, B ₂ O ₃ or BN or B ₄ C, Si
O ₂ , NiO and CuO were prepared and weighed and mixed so that a porcelain having the composition shown in Table 1 was obtained. 80 this mixture
It was calcined at a temperature of 0 to 900 ° C. and pulverized. An organic binder was added to the pulverized powder and kneaded, and the obtained slurry was formed into a sheet having a thickness of 1 mm by a doctor blade method. This ceramic green sheet is 30 mm in length and 10 in width.
The binder component is burned at a temperature of 900 ° C. in a nitrogen-steam reducing or non-oxidizing atmosphere using nitrogen passed through water vapor as a carrier gas, which is cut into a size of mm, and is shown in Table 1. A porcelain was obtained by firing at each temperature for 1 hour.

In addition, this ceramic green sheet is 3 mm in length and 20 in width.
Cut into mm-shaped plates, stack 3 sheets, and 2000 kg
It was pressed at a pressure of / cm ² to form a prism. Then, this was fired by the above method to obtain a sample for measuring the thermal expansion coefficient.

The characteristics of these samples were measured under the respective conditions and measuring methods as follows, and the results shown in Table 1 were obtained.

Dielectric constant: A value measured at a frequency of 1 MHz.

Dielectric loss: A value measured at a frequency of 1 MHz.

Specific resistance: A value when 100 V DC is applied to the sample.

Thermal expansion coefficient: A value calculated from the following formula.

α = ΔL / L (T ₂ −T ₁ ) + αSiO ₂ where α: coefficient of thermal expansion ΔL: apparent elongation of sample due to heating (mm) L: length of sample at room temperature (mm) T ₁ : room temperature T ₂ : 500 ° C. αSiO ₂ : the coefficient of thermal expansion of quartz glass.

The results in Table 1 were judged according to the following criteria.

Sintering temperature: 1020 ° C or less (Cu, Ag, Ag-Pd,
Dielectric constant (ε): 5 or less under the condition of 1MHz Dielectric loss (tan δ): 0.2% or less under the condition of 1MHz Specific resistance: 10 ¹² Ω under the condition of DC voltage 100V・ Cm or more Thermal expansion coefficient: 4 × 10 ⁻⁶ / with an average value of 25 to 500 ° C.
C. or less In addition, those marked with * in Table 1 are outside the scope of the present invention, and all other items are within the scope of the present invention.

As is clear from Table 1, the reason why the composition range of the low temperature sintered ceramic composition for a multilayer substrate of the present invention is limited is as follows.

(1) When the cordierite content exceeds 95% by weight, the sintering temperature becomes higher than 1020 ° C, which is not preferable (Sample No. 1). On the other hand, if the cordierite content is less than 50% by weight, the coefficient of thermal expansion will be greater than 4 × 10 ⁻⁶ / ° C., and ε will be 5
It is not preferable because it becomes larger (Sample No. 3, 1
0).

(2) When B ₂ O ₃ exceeds 30% by weight, tan δ is 0.
It becomes larger than 2% and foaming is likely to occur during firing, which is not preferable (Sample Nos. 5 and 6). On the other hand, B ₂ O ₃
Is less than 4% by weight, the firing temperature is higher than 1020 ° C., which is not preferable (Sample Nos. 1, 8, 10).

(3) If the SiO ₂ content exceeds 46% by weight, the coefficient of thermal expansion is 4 ×
It is not preferable because it is higher than 10 ⁻⁶ / ° C. and the curvature of the substrate during firing also becomes large (Sample No. 10). On the other hand, if SiO ₂ is less than 1% by weight, the firing temperature is 1020 ° C.
It becomes higher and is not preferable (Sample No. 12).

(4) By adding a component composed of one or more of CuO and NiO, the sintering temperature is lowered and the metallization strength is improved (Sample Nos. 20, 22, 24).

However, when added in an amount of 15% by weight or more, the specific resistance becomes 10 ¹²
It is less than Ω · cm, which is not desirable (Sample Nos. 19 and 2)
1, 23).

(f) Effects of the Invention The low temperature sintered porcelain composition for a multilayer substrate according to the present invention has the following effects.

(1) Ag, Ag-Pd as a conductive material for forming a circuit pattern, which can be sintered at a temperature of 1020 ° C or less
A relatively inexpensive precious metal such as can be used. Further, since it can be fired in a non-oxidizing atmosphere, inexpensive base metals such as Cu and Ni can be used as the conductive material of the circuit pattern. Furthermore, a cermet material can be used when forming a resistance pattern inside.

(2) If the thermal expansion coefficient is as small as 4 × 10 ⁻⁶ / ° C. or less and is approximately equal to the thermal expansion coefficient of silicon, even if a silicon chip is mounted on this substrate, the silicon chip will crack due to thermal stress. There is no danger of this occurring.

(3) The relative permittivity is 5 or less, which is smaller than that of alumina, and the signal delay time can be shortened to 3/4 or less of that of alumina.

[Brief description of drawings]

FIG. 1 is a diagram showing the composition range of cordierite.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunobu Yoneda 2-26-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Yukio Sakabe 2-26-10 Tenjin, Nagaokakyo, Kyoto Stock Company Murata Manufacturing Co., Ltd. (72) Inventor Harufumi Bandai, 2-10-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd. (56) References JP 58-95643 (JP, A) JP 63-151645 (JP) , A)

Claims (2)

[Claims] 1. 50 to 95% by weight of cordierite, B ₂
A low temperature sintered porcelain composition for a multi-layer substrate, comprising O _{3 in an amount} of 5 to 20% by weight and SiO ₂ in an amount of ₁ to 46% by weight. 2. One or more nickel and / or copper oxides as additives are Ni based on the main component.
The low temperature sintered porcelain composition for a multilayer substrate according to claim (1), which contains 15% by weight or less of O and / or CuO.