JPS62187160A - Low temperature sinterable ceramic composition for multi-layer 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 multilayer substrates, and in particular to a multilayer porcelain composition formed by laminating a plurality of sheet-like porcelains and forming a circuit between the porcelains. The present invention relates to a low-temperature sintered ceramic composition for multilayer substrates, which is suitable for electric circuit boards.

(Prior art) Generally, with the miniaturization of electronic devices, ceramic substrates are commonly used to mount various electronic parts that make up electric circuits. A multilayer porcelain substrate made by laminating a plurality of porcelain sheets has been developed. Alumina is used as the ceramic material for this type of multilayer ceramic substrate, but its sintering temperature is as high as 1,500 to 1,600°C, which causes the following problems. First, sintering requires a large amount of energy, which increases manufacturing costs. Further, since the conductive material for the internal circuits formed inside the substrate is limited to, for example, tungsten or molybdenum, which can withstand high sintering temperatures, the resistance of the internal circuits becomes large. 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 JP-A-57-1
As in the composition disclosed in Publication No. 84289, B
A5nO, to which a large amount of boron is added, is 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. Also, JP-A-57-184289
With the composition disclosed in the publication, the calcined product becomes glassy, which not only makes it difficult to crush, but also causes boron to evaporate violently during firing, causing it to react with the conductive material and damage the furnace material. The problem arises of giving.

Therefore, the main object of the present invention is to provide a low-temperature sintered multilayer substrate that can be sintered at a low temperature, has high specific resistance, low dielectric constant, and low dielectric loss, and has a thermal expansion coefficient of alumina or less. An object of the present invention is to provide a porcelain composition.

(Means for Solving the Problems) In this invention, the Si component is 25 to 80 in terms of Sin.
1iffi%, Ba component is 15-70 in terms of BaO
Weight %, B component is B20. 1.5 to 5% by weight converted to
, A1 component is 1 to 30% by weight in terms of AJZ03, M
This is a low-temperature sintered ceramic composition for a multilayer substrate, which contains g component in an amount of more than 0% by weight and not more than 15% by weight in terms of MgO.

In addition, as trace additives, 20°Na, O, and Li2O are added.
A small amount of alkali metal oxides such as (1 type or less) may be added in an amount of 1.0% by weight or less.

When manufacturing an electric circuit board using the ceramic composition for electric circuit boards of the present invention, for example, Si, Ba, B, A
1 and Mg oxide or a powder of a compound that decomposes during firing to become an oxide is weighed and prepared, the raw material mixture is calcined at 850 to 950°C, then crushed, and the powder is kneaded with a binder. The green sheet may be formed into a sheet shape, and then the obtained green sheet may be fired at 850 to 1000°C in an oxidizing atmosphere, a non-oxidizing atmosphere, or a reducing atmosphere. In addition, when manufacturing a multilayer electric circuit board, a circuit is printed on a green sheet with a conductive paste containing a conductive material such as Ag, Ag-Pd, Cu, or Ni, and after laminating multiple layers of them, the conductive material is The paste may be fired in an atmosphere appropriate for the conductive material that makes up the paste. When using base metals such as Cu or Ni as internal conductive materials, firing may be performed in a non-oxidizing or reducing atmosphere to prevent oxidation of the base metals. Preferably, it is fired. For example, nitrogen is passed through water vapor (70°C) as a carrier gas to create a nitrogen-steam atmosphere containing trace amounts of oxygen and hydrogen.
Normally, Nt99.7-99.8%), 850-100
It is preferable to bake at 0°C. Note that the reason why a small amount of oxygen is included is that even if the binder used to form the green sheet is calcined, it remains as carbon, so that this is completely burned and removed.

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 ■) 13acO+ or Ba02S i Oz as a raw material,
Alx 03 , Bz O+ or BN or B4C
1MgO or MgCO3 was weighed and mixed to have the composition shown in Attached Table 1. Add this mixture to 850-950
After calcining at °C and pulverizing, an organic binder was added and kneaded, and the mixture was formed into a sheet with a thickness of 1 fl by a doctor blade method. This green sheet is 3011mm long. horizontal 10
It was cut into pieces of mm and fired in air at 850 to 1000°C for 1 hour to obtain porcelain. Further, this green sheet was canted into a rectangular plate shape with a length of 3 m and a width of 20 squares, and three of these sheets were laminated and pressed at 200 kg/aa to form a prismatic 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 using the respective conditions and measurement methods as follows, and the results shown in Attached Table 1 were obtained.

Dielectric constant: IMHz condition Dielectric loss: IMHz condition ratio Resistance: Direct current 100V condition bending strength: Calculated from the following equation (1) Tr: bending strength, P: load when the sample is broken ( kg
), Il, distance between supporting points (am), b: width of sample (cm), d: thickness of sample (cm) coefficient of thermal expansion: the following (
2) Calculated from the formula α: Coefficient of thermal expansion, ΔL: Apparent elongation of the sample due to heating (xi), L: Length of the sample at room temperature (ms), 'I
+: room temperature, Tz: 500°C, αSin: coefficient of thermal expansion of quartz glass.
While creating a green sheet with a grain size of 3 to 0.4, the grain size is 5.
A conductive paste is prepared by mixing Ag or Ag-Pd conductive material powder of µm or less and an organic vehicle at a weight ratio of 80:20, and each conductive paste is applied to the entire surface of the green sheet. Three sheets were printed, laminated, thermocompressed, and fired in air at 850 to 1000°C. 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 area resistance of Ag
-Pd had a sheet resistance of 20 mΩ/mouth.

(Example ■) Using the green sheet with a thickness of 11 m prepared in Example f, the green sheet was cut into a prismatic shape with a length of 30 mm and a width of 10 mm, and was heated to 600°C to preliminarily burn the binder. , complete combustion at 900℃, then steam (70℃)
950-1000 in a reducing or non-oxidizing atmosphere of nitrogen-steam with nitrogen passed through as a carrier gas.
The sample was baked at ℃ for 1 hour. Further, in the same manner as in Example I, 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. Using these samples, each of the properties measured in Example 2 was measured, and the results shown in Attached Table 2 were obtained.

In addition, the thickness 0.3 to 0.4 fl described in the latter half of Example
A copper paste made by mixing copper powder with a particle size of 50 μm or less and an organic vehicle at a weight ratio of 80:20 is printed on the surface of the green sheet, and three sheets of this are stacked and bonded by thermocompression. - Calcined at 950-1000°C for 1 hour in a reducing or non-oxidizing atmosphere of water vapor. The Cu conductor of the multilayer ceramic substrate thus obtained was not oxidized and exhibited good conductivity, and its sheet resistance was 2 mΩ/hole.

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

Sintering temperature: 1000℃ or less (Cu conductor and Ag-P
d Usable temperature of conductor, except for Ag-Pd conductor
:Pd=80:20) Dielectric constant: 1O or less under IMHz conditions (below the dielectric constant of alumina) Dielectric loss: 0.2% or less under IMHz conditions Breaking strength: 1500 kg/- or more Thermal expansion coefficient: 8. Ox 10-'/ is below (below the value of the thermal expansion coefficient of alumina) Those marked with * in Attached Table 1 and Attached Table 2 are outside the scope of this invention, and the others are outside the scope of this invention. It is inside.

As is clear from Attached Tables 1 and 2, the reason for limiting the composition of the low-temperature sintered ceramic composition for multilayer substrates of the present invention to the box surface is as follows.

(1) When SiO exceeds 80% by weight, the bending strength is 1
500kg/crl ungrooved and sintering temperature 1000
℃, which is undesirable (Appended Tables 1 and 2)
(See sample number 1). On the other hand, if SiO2 is less than 25% by weight, the dielectric constant becomes greater than 10, which is not preferable (
(See sample number 4 in Attached Tables 1 and 2).

(2) If BaO exceeds 70% by weight, the dielectric constant becomes greater than 10, which is undesirable (see Sample No. 5 in Attached Tables 1 and 2). On the other hand, if BaO is less than 15% by weight, the bending strength will be less than 1500 kg/cd, which is not preferable (see sample number 12 in Attached Tables 1 and 2).

(If 31Aj2,0. exceeds 30% by weight, the dielectric loss will become larger than 0.2%, which is undesirable (see Sample No. 9 in Attached Tables 1 and 2). On the other hand, when Al2O is less than 1% by weight, , the sintering temperature becomes higher than 1000°C, which is undesirable (see sample number 7 in Attached Tables 1 and 2).

(4) When MgO exceeds 15% by weight, the sintering temperature is 10% by weight.
It is undesirable to be higher than 00℃ (Appended Tables 1 and 2)
(See sample number 13). On the other hand, when MgO is not contained, the thermal expansion coefficient becomes larger than 8.0×1 (Ib/l), which is not preferable (see sample number 10 in Attached Tables 1 and 2).

If (518z C)+ exceeds 5% by weight, the bending strength becomes less than 1500 kg/cj, which is not preferable (see sample number 15 in Attached Tables 1 and 2). On the other hand, B2O3
If it is less than 1.5% by weight, the sintering temperature will be higher than 1000°C, which is undesirable (see sample number 18 in Attached Tables 1 and 2).

(Effects of the Invention) According to the present invention, it is possible to obtain a multilayer substrate with excellent characteristics, which has high resistivity, low dielectric constant, little dielectric loss, and has a coefficient of thermal expansion smaller than that of alumina. In addition, in the manufacturing process, processing such as pulverization after calcination is easy, and it can be fired at 1000°C or less, and even if fired in an oxidizing or non-oxidizing atmosphere, the electrical properties
Base metals, such as Ag, Ag-Pd paste Cu and Ni, can be used as the inner conductor material, as there is no change in physical or thermal properties and no reaction with the inner conductor. It is possible to reduce the cost of the substrate.

Furthermore, since the coefficient of thermal expansion is less than or equal to alumina, cracks due to thermal stress are less likely to occur.

Furthermore, a resistor can also be formed by printing a cermet resistor material or the like as a conductor.

Claims (1)

[Claims] The Si component is 25 to 80% by weight in terms of SiO_2, the Ba component is 15 to 70% by weight in terms of BaO, the B component is 1.5 to 5% by weight in terms of B_2O_3, The Al component is 1 to 30% by weight in terms of Al_2O_3, and the Mg component is more than 0% by weight and 15% by weight in terms of MgO.
A low-temperature sintered ceramic composition for a multilayer substrate, which is included below.