JPH0578165A - Composition for ceramic substrate - Google Patents

Abstract

PURPOSE:To provide the title composition to be used for producing various multilayer wiring boards, calcinable at extremely low temperatures, capable of using pastes such as of Au or Ag as internal electrodes, adequate in resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength and flexural strength etc., also adjustable in the rate of change in electrostatic capacity with temperature change to + or -0 to + or -100ppm/ deg.C. CONSTITUTION:The objective composition comprising (A) 60-95wt.% of glass frit composed of (1) 50-60wt.% of Al2O3, (2) 25-30wt.% of SiO2, (3) 7.8-8.3wt.% of PbO, (4) 3.3-3.8wt.% of CaO, (5) 2.5-3.0wt.% of B2O3, (6) 1.1-1.5wt.% of MgO, (7) 1.1-1.5wt.% of Na2O, and (8) 0.8-1.1wt.% of K2O and (B) 5-40 wt.% of a titanate (SrTiO3 or CaTiO3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a ceramic substrate, which is suitable for a multilayer wiring substrate for forming electronic circuits such as conductors and resistors in multiple layers.

[0002]

2. Description of the Related Art In recent years, as electronic parts for forming a circuit in multiple layers, a first method of manufacturing a circuit by alternately printing a circuit and an insulating layer on a fired alumina substrate and baking the printed circuit board and a non-fired method. There is a second method in which the circuit is printed on the ceramic substrate, the circuits are laminated so that the circuits do not come into contact with each other, the circuit is pressed, and then the circuit is fired.

In the case of the first method, the insulating layer formed thereon is uneven due to the influence of the circuit, and the unevenness becomes larger in the upper layer. If this unevenness becomes large, it becomes difficult to print the next circuit on it, and the limit is usually around 10 layers.

On the other hand, in the second method, since the circuit is always printed on the substrate in a nearly flat state,
It is possible to manufacture one having a large number of laminated layers and to form a high-density integrated circuit. As the ceramic substrate composition used for the substrate of the second method, Al ₂ O ₃ powder and 15% by weight or less of glass powder fixed with an inorganic binder, or Al 2 O ₃ —SiO ₂ system containing Pb or B is used. Some of them are mixed with and baked at a low temperature.

[0005]

However, the Al ₂ O ₃ powder of the second conventional method and the glass powder of 15% by weight or less fixed by an inorganic binder have an extremely high firing temperature of 1450 to 1600 ° C. Since the cost is high, expensive materials such as Mo and W, which do not deteriorate at this firing temperature, are used as the material for forming the circuit, and the workability is poor because firing is required in a reducing atmosphere.

Al ₂ O ₃ --SiO ₂ system containing 10 w of Pb and B
The material mixed with t% or more and fired at a low temperature had a problem that the rate of change in capacitance with temperature change (hereinafter referred to as TCC) was large.

The object of the present invention is to solve the above-mentioned conventional problems and to use a paste of Au, Ag, Ag-Pd, Cu or the like as an internal electrode, which can be fired at an extremely low temperature, that is, 750 to 950 ° C. Volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc.
Satisfies various characteristics as a multilayer wiring board for forming electronic circuits such as conductors and resistors in multiple layers, and has a TCC of ± 0 pp
It is intended to provide a composition for a ceramic substrate that can be adjusted to m / ° C to 100 ppm / ° C.

[0008]

The composition for a ceramic substrate of the present invention, which has solved this problem, comprises glass frit of 60 to 95% and titanate of 5 to 40% by weight. Examples of the titanate include SrTiO ₃ , C
There is a TiO ₃ . Further, the glass frit includes Al ₂ O ₃ 50 to 60% by weight and SiO ₂ by weight%.
25-30%, PbO 7.8-8.3%, CaO
3.3-3.8%, B2 O3 2.5-3.0%, Mg
O 1.1-1.5%, Na ₂ O 1.1-1.5%,
K ₂ O 0.8 to 1.1% is desirable.

When the glass frit is less than 60% by weight, the firing temperature becomes high, and it is difficult to perform the firing at the low temperature which is the subject of the present invention. On the other hand, when the glass frit is more than 95% by weight, the bending strength and the moisture resistance of the fired product are deteriorated, which is not preferable. Also, it becomes difficult to adjust the TCC.

When the content of SiO2 is less than 25% by weight, the softening temperature becomes low and a large amount of deformation occurs during firing.
If it is more, the firing temperature becomes too high, which is not preferable.

PbO is preferably added in an amount of 7.8% by weight or more in order to improve the solubility of glass. If it is more than 8.3% by weight, the softening temperature of the glass tends to be too low, and large deformation tends to occur during firing, which is not preferable.

CaO is added for the purpose of improving the meltability and adjusting the coefficient of thermal expansion of glass during the production of glass frit. If it is less than 3.3% by weight, the above-mentioned meltability is not improved and devitrification is likely to occur during the production of frit. When it is more than 3.8% by weight, the coefficient of thermal expansion becomes too large, which is not preferable.

B ₂ O ₃ is a flux and contains 2.5% by weight.
If it is less than the above range, the firing temperature becomes too high, and if it exceeds 3.0% by weight, the chemical stability of the glass is deteriorated, which is not preferable.

MgO is added for the purpose of improving the meltability and adjusting the coefficient of thermal expansion of glass during the production of glass frit. If it is less than 1.1% by weight, the above-mentioned meltability is not improved and devitrification is likely to occur during the production of frit. If it exceeds 1.5% by weight, the coefficient of thermal expansion becomes too large, which is not preferable.

Na2O is preferably added in an amount of 1.1% by weight or more in order to improve the solubility of glass. If it is more than 1.5% by weight, the softening temperature of the glass tends to be too low, and large deformation tends to occur during firing, which is not preferable.

K2O is preferably added in an amount of 0.8% by weight or more in order to improve the melting property of glass. If it exceeds 1.1% by weight, the softening temperature of the glass tends to be too low, and large deformation tends to occur during firing, which is not preferable.

Al ₂ O ₃ is preferably added in an amount of 50% by weight or more in order to improve the mechanical strength of the ceramic. 6
The addition of 0% by weight or more is not preferable because the firing temperature becomes too high.

[0018]

With this structure, a paste such as Au, Ag, Ag-Pd, Cu, etc., which is widely used in thick film technology, can be applied as an internal electrode because it can be fired at a temperature extremely lower than before, that is, 750 ° C to 950 ° C. In addition, the fired body has a large bending strength, an excellent thermal conductivity, a relatively small dielectric constant, a large insulation resistance, and an excellent heat resistance, and in particular, a glass having a positive TCC characteristic. By the firing reaction of frit and titanate system with negative TCC characteristics, TC
The adjustment of C can be facilitated.

[0019]

EXAMPLES Examples of the present invention will be described below.

First, the glass frit is made of SiO ₂ by weight%.
27%, PbO 8.1%, CaO 3.5%, B ₂
O ₃ 2.7%, MgO 1.3%, Na ₂ O 1.3
%, K ₂ O 1.1%, each raw material is prepared by a usual method, melted with stirring at a temperature of 1400 to 1500 ° C., and after melting, granulated or formed into flakes. Then, 55% by weight of Al ₂ O ₃ was added thereto to prepare a glass frit.

Next, the glass frit and SrTiO _{3 of} titanate were weighed so as to be 90% by weight and 10% by weight, respectively, pulverized and mixed in a ball mill to obtain a composition of the present invention. 10% by weight of a binder was added to the pulverized and mixed composition, which was granulated and molded, and then fired at 900 ° C. for 15 minutes. When the relative density of this fired body was measured, it was 9
Since it was 9.98%, the diameter is 30 mm and the thickness is 0.35.
After processing into mm, the Ag electrode was baked and the TCC was measured, and it was ± 0 ppm / ° C at -25 ° C to + 85 ° C.

Therefore, various compositions were added to the pulverized and mixed composition.
Add binder, plasticizer, solvent and knead to obtain viscosity of 10p
A paste of s to 30 ps was prepared. Always use this paste
With a doctor blade method of 0.1 mm thick
I made it a sheet. Stack 50 sheets of this green sheet,
After that, thermocompression-bonded at a pressure of about 50 tons at 35 ° C,
It was baked at 900 ° C. for 15 minutes. Various characteristics of baked sheets
The specific resistance was measured to be 10¹⁴ ~¹⁶ 
Ω, dielectric constant 8 to 11, dielectric loss tangent ≦ 5 × 10^-Four , Insulation breakdown
Breaking strength 700-900KV / cm, bending strength 2000-
2500 kg / cm ² , TCC (-25 ℃ ~ +85 ℃)
It was ± 0 ppm / ° C. That is, electrons such as conductors and resistors
Good ceramic as a multilayer wiring board for forming circuits in multiple layers
The result satisfying the characteristics of the Mick substrate was obtained.

Furthermore, the glass frit and SrTiO 3
₃ were weighed so as to be 94% by weight and 6% by weight, respectively, pulverized and mixed by a ball mill, and a green sheet fired body was obtained by the above method. The firing temperature in this case is 80
It was 0 ° C. When various properties of the fired sheet were measured, the volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc. were similar to the above. TCC is
It was +50 ppm / ° C.

When the glass frit and CaTiO ₃ are 70% by weight and 30% by weight, respectively, the firing temperature is 870.
At 0 ° C., the volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc., were the same values as above. TCC
Was -20 ppm / ° C.

When the glass frit and CaTiO 3 are 60% by weight and 40% by weight, respectively, the firing temperature is 920.
At 0 ° C., the volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc., were the same values as above. TCC
Was -30 ppm / ° C.

Further, similar results were obtained with respect to the fired body in which a paste of Au, Ag, Ag-Pd, Cu or the like was laminated as an internal electrode. The above results are shown in Table 1.

[0027]

[Table 1]

As can be seen from Table 1, according to the present invention, the firing can be realized at an extremely low temperature as compared with the conventional composition, and the TCC can be easily adjusted.

[0029]

As described above, according to the present invention, it becomes possible to realize firing at an extremely low temperature, that is, 750 to 950 ° C., and a paste of Au, Ag, Ag—Pd, Cu or the like is used as an internal electrode. It is now possible to use. Further, various required characteristics of the fired body, that is, characteristics such as volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc., and characteristics as a multilayer wiring board for forming electronic circuits such as conductors and resistors in multiple layers. And TCC is ± 0ppm
It is possible to realize a composition for a ceramic substrate, which can be easily adjusted from / ° C to ± 100 ppm / ° C.

Claims (4)

[Claims] 1. A glass frit 60-95 in weight percent.
% And 5 to 40% titanate, a composition for a ceramic substrate. 2. The composition for a ceramic substrate according to claim 1, wherein the titanate is SrTiO ₃ . 3. The composition for a ceramic substrate according to claim 1, wherein the titanate is CaTiO ₃ . 4. The glass frit is in weight% and is Al.
₂ O ₃ 50-60%, SiO ₂ 25-30%, Pb
O 7.8-8.3%, CaO 3.3-3.8%, B
₂ O3 2.5-3.0%, MgO 1.1-1.5
%, Na ₂ O 1.1-1.5%, K ₂ O 0.8-1.
The composition for a ceramic substrate according to claim 1, which is composed of 1%.