JPS62256758A - Low temperature sintered ceramic composition for multilayer substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a low-temperature sintered porcelain composition for a multilayer substrate, and in particular to a multilayer porcelain composition 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 ceramic composition for multilayer substrates, which is suitable for substrates.

(Prior art) Generally, with the miniaturization of electronic devices, ceramic substrates are commonly used to mount various electronic components that make up electric circuits. A multilayer porcelain substrate has been developed in which a plurality of patterned unfired porcelain sheets are laminated and then fired and integrated. Alumina is used as the porcelain material for this type of multilayer porcelain substrate, and its sintering temperature is 1500 to 16
Because the temperature was as high as 00°C, there were the following problems. First, sintering requires a large amount of energy, which increases manufacturing costs. Further, since the conductive materials that can be formed inside the substrate, such as internal circuits, are limited to materials such as tungsten and molybdenum that can withstand high sintering temperatures, the resistance of the internal circuits and the like increases. Furthermore, since the coefficient of thermal expansion of alumina is larger than that of the silicon chip, thermal stress is applied to the silicon chip, causing cracks. Therefore, in order to solve these problems, as a ceramic composition for a substrate that can be sintered at a low temperature, a ceramic composition in which a large amount of crystallized glass component is added to alumina, or as disclosed in JP-A-57-184289, has been proposed. As shown in the composition described above, BaSnO3 with a large amount of boron added thereto is used. Also, JP-A No. 60-226454, or JP-A No. 60-2
As disclosed in Publication No. 27311, alumina,
Those containing components such as silica, alkaline earth metal oxides, boron, lithium oxide, and zinc oxide are used.

(Problems to be Solved by the Invention) However, in a composition in which a large amount of crystallized glass component is added to alumina, a large number of pores are present in the resulting porcelain.
A problem arises in that migration occurs between the conductor paths via the holes. Furthermore, in the composition disclosed in JP-A-57-184289, the calcined material becomes glassy, which not only makes it difficult to crush, but also causes the boron to evaporate violently during firing, resulting in a conductive material. Problems arise with reactions and damage to the materials in the furnace. Also, JP-A No. 60-226454, JP-A No. 60-2273
However, the composition disclosed in Japanese Patent No. 11 suffers from similar problems because it uses a large amount of boron. Further, the presence of a large amount of boron causes a problem of deterioration of the resistor when a cermet resistor is formed on the surface thereof. Furthermore, when a conductor is formed on the surface, the presence of a large amount of boron deteriorates the characteristics of the conductor.

(Objective of the Invention) Therefore, the main object of the present invention is to be able to sinter at a low temperature, have high specific resistance, low dielectric constant, small dielectric loss, and have a thermal expansion coefficient similar to that of aluminium. An object of the present invention is to provide a low-temperature sintered ceramic composition for a multilayer substrate as follows.

Further, the object of this invention is to provide a non-oxidizing atmosphere with 10
It can be sintered at low temperatures below 00°C, and can be used as a conductor.
u) To provide a low-temperature sintered ceramic composition for a multilayer substrate in which base metals such as nickel (Ni) can be used.

(Means for Solving the Problems) This invention has a Si component of 25 to 25 in terms of Si02.
70% by weight, Sr component is 25 to 60% by weight in terms of SrO, A1 component is 1% to 30% by weight in terms of Al2O3
Weight%, Ca component exceeds 0% by weight in terms of CaO2
This is a low-temperature sintered ceramic composition for a multilayer substrate, which contains a B component of 1.5% to 5% by weight in terms of B2O3.

Note that at least one kind of alkali metal oxide such as Li01K20 and Na20 may be added as a trace additive in an amount of 1.0% by weight or less. The reason for adding an alkali metal oxide is that the firing temperature can be further lowered.

When manufacturing a multilayer circuit board using the low-temperature sintered ceramic composition for multilayer boards of the present invention, for example, Si, 5rXAl
, Ca and B oxides, or powders of compounds that decompose into oxides during firing are weighed and prepared, the raw material mixture is calcined at 850 to 950°C, then crushed, and the powder is kneaded with a binder. Then, the green sheet obtained is fired at 850 to 1000°C in an oxidizing atmosphere or a non-oxidizing atmosphere. In addition, when manufacturing multilayer circuit boards, A
A circuit pattern is printed using a conductive paste containing a conductive material such as G, Ag-Pd, Cu, or Ni, and then multiple sheets of these are laminated and then fired in an atmosphere appropriate for the conductive material that makes up the conductive paste. Bye. C as internal conductive material
When using base metals such as u or Ni, it is preferable to sinter in a non-oxidizing atmosphere in order to prevent their oxidation. For example, water vapor (70%
°C) and pass through a fine nitrogen-steam atmosphere (usually N299.7~99°C) containing trace amounts of oxygen and hydrogen.
．． 8%), preferably calcined at 850-1000°C. The reason why a small amount of oxygen is included is to completely burn off and remove the binder used for forming the green sheet during the calcination stage so that it does not remain as carbon.

The above objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments.

(Example 1) As a raw material, Si02, SrCO3 or 5rO1A
1203, CaO or Ca CO3, B2O3 or BN or B4C, were weighed and mixed to have the composition shown in Attached Table 1. This mixture was calcined at 850 to 950°C, pulverized, then kneaded with an organic binder and formed into a sheet with a thickness of 1 mm using a doctor blade method. This green sheet was cut into pieces 30 mm long and 10 mm wide, and fired in air at each temperature shown in Attached Table 1 for 1 hour to obtain porcelain. Also, use this green sheet as fir 3mm.
It was cut into a rectangular plate shape with a width of 20 mm, and three of these plates were laminated and pressed at 2000 kg/cm2 to form a rectangular column shape. This was then fired by the method described above to obtain a sample for thermal expansion measurement.

Regarding these samples, each characteristic was measured and determined using the respective conditions and measurement methods as follows, and the results shown in Attached Table 1 were obtained.

In addition, regarding the specific resistance, both are 1XIO13Ω・a
A value of m or more was obtained.

Dielectric constant: IMHz condition Dielectric loss: IMHz condition Specific resistance: DC 100μ condition Transverse strength Calculated from the quadratic equation (1) In the formula, Tr: Transverse strength, P: When the sample is cut Load (Xg) l: Distance between fulcrums (am) b = Convergence of sample (am) d: Thickness of sample (am) Coefficient of thermal expansion: Calculated from the following formula (2), α: Coefficient of thermal expansion ΔL: Apparent elongation of the sample due to heating (mm) L: Length of the sample at room temperature (mm) T1: Room temperature T: 500°C αS i O2' Thermal expansion coefficient of silica glass .3 to 0.4 mm green sheets are created, while Ag or Ag particles with a particle size of 5 μm or less are produced.
- Pd conductive material powder and organic vehicle at a weight ratio of 80
: Adjust the conductive paste by mixing at a ratio of 20:
Each of the conductive pastes was printed on the entire surface of the green sheet described above, three of these sheets were laminated, thermocompression bonded, and fired in air at each temperature shown in Attached Table 1. The organic vehicle used was ethyl cellulose diluted 10 times with α-terpineol.

When the reaction between the porcelain and Ag or Ag-Pd was analyzed for the thus obtained multilayer ceramic substrate, no reaction was observed between the two, and both Ag and Ag-Pd showed good conductivity. The areal resistance of A is 2mΩ/mouth.
The sheet resistance of g-Pd was 20 mΩ/hole.

(Example 2) Using the 1 mm thick green sheet prepared in Example 1, cut it into a rectangular plate shape with a fift of 30 mm and a width of 10 mm, and passed it through water vapor (70°C). Nitrogen was used as a carrier gas. The green sheets were heat treated at a temperature of 900° C. in a non-oxidizing nitrogen-steam atmosphere to completely burn out the binder in the green sheets, and then fired for 1 hour at each temperature shown in Attached Table 2 to prepare samples. Further, in the same manner as in Example 1, a pressure-molded prismatic sample was also fired in the same manner as described above, and was used as a sample for measuring the coefficient of thermal expansion. Then, using these samples, test was carried out under the same conditions as in Example 1! Each of the determined characteristics was measured, and the results shown in Attached Table 2 were obtained. In addition, regarding the specific resistance, a value of 1×10 13 Ω·Cm or more was obtained in all cases.

In addition, the thickness of 0.3 to 0.4 mm described in the latter half of Example 1
Using a green sheet of - Calcined for 1 hour at each temperature shown in Attached Table 2 in a non-oxidizing atmosphere of water vapor. The Cu conductor of the multilayer ceramic substrate obtained in this way is not oxidized and exhibits good conductivity.
Its sheet resistance was 2 mΩ/mouth.

The results in Attached Tables 1 and 2 were judged according to the following criteria.

Sintering temperature: 1000℃ or less (Cu conductor and Ag-Pd
Usable temperature of conductor, except for Ag-Pd conductor: Ag: Pd = 80: 20
) Dielectric constant (ε): 10 or less under IMHz conditions (less than the dielectric constant of alumina) Dielectric loss (tan δ): 0°2% under IMHz conditions
When a cermet resistor that can be used in a non-oxidizing atmosphere is formed on the surface, the cermet resistor on the multilayer ceramic substrate according to the present invention is Properties equivalent to those of the alumina substrate were obtained.
It was confirmed that when t was set to 6%, soldering performance deteriorated.

In addition, in Attached Table 1 and Attached Table 2, those marked with * are outside the scope of this invention, and the others are within the scope of this invention.

As is clear from Attached Tables 1 and 2, the reason why the composition range of the low temperature sintered ceramic composition for multilayer substrates of the present invention is limited to the above range is as follows.

(1) When Si02 exceeds 70%, the bending strength becomes less than 1500Kg/cm2, and the sintering temperature becomes 10%.
It is not preferable because it becomes higher than 00°C (see sample number 1). On the other hand, when 5102 is less than 25%, the dielectric constant is 1
This is not preferable because it is larger than 0 (see sample number 4).
.

(2) If SrO exceeds 60% by weight, the dielectric constant becomes greater than 10, which is not preferable (see sample number 5). On the other hand, when SrO is less than 25% by weight, the sintering temperature is 1000%
℃, which is not preferable (see sample number 8).

(3) If the weight of A1203 exceeds 30%, the dielectric loss will be greater than 0.2%, which is undesirable (sample number 9#
(see). On the other hand, when Al2O3 is less than 1% by weight, the sintering temperature becomes higher than 1000°C, which is not preferable (see sample number 12).

(4) CaO is 20! If it exceeds ffi%, the sintering temperature will become higher than 1000°C, which is not preferable (see sample number 13). On the other hand, when CaO is not fully contained, the thermal expansion coefficient is 8. OXI○-6/°C, which is not preferable (see sample number 15).

(5) When B203 exceeds 5% by weight, the bending strength is 15%.
00Kg/cm2, which is not preferable (see sample number 16). On the other hand, if B2O3 is less than 1.5% by weight, the sintering temperature will be higher than 1000°C, which is not preferable (see sample number 19).

(Effects of the Invention) According to the present invention, the material has high resistivity and low dielectric constant, has low dielectric loss, and has a smaller number of thermal expansion cases than alumina. In addition, in the manufacturing process, processing such as crushing after calcination is easy, and moreover, it can be heated at temperatures below 1000°C. Even when fired in a non-oxidizing atmosphere during operation, there is no change in electrical, physical, or thermal properties, and no reaction with the internal conductor is observed, so it can be used as an internal conductor material. For example, Ag, Ag-Pd paste,
Base metals such as Cu and Ni can be used, and the cost of the multilayer board can be reduced.

Since the coefficient of thermal expansion is less than that of alumina, cracks are less likely to occur due to thermal stress. Furthermore, a resistor can also be formed by printing a cermet resistive material or the like.

Claims (1)

[Claims] (1) The Si component is 25 to 70% by weight in terms of SiO_2, the Sr component is 25 to 60% by weight in terms of SrO, the Al component is 1 to 30% by weight in terms of Al_2O_3, and the Ca component is More than 0% by weight and 20% by weight in terms of CaO
Hereinafter, a low-temperature sintered ceramic substrate for a multilayer substrate contains a B component of 1.5% to 5% by weight in terms of B_2O_3.