JPH0480869B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a ceramic composition for low temperature firing that can be fired at low temperatures and has characteristics such as high resistivity, low dielectric constant, and low dielectric loss. (Prior Art) With the miniaturization of electronic devices, many ceramic substrates are being used to mount various components constituting circuits. Recently, development is progressing toward multilayer ceramic substrates to further increase packaging density. Alumina is generally known as a material for this multilayer ceramic substrate. However, alumina has a firing temperature of 1500~
Because the temperature is as high as 1,600℃, a lot of energy is required for firing. Further, high melting point materials such as W and Mo are used as internal dielectric materials to be fired simultaneously with alumina, but these metals have a drawback of high specific resistance and high circuit resistance themselves. Therefore, if it is a porcelain material that can be fired at a lower temperature than alumina, the energy for firing will be less, and if it is possible to fire at a temperature below 1000℃, conductive materials such as Ag, Ag-Pd, and Cu can be used. In addition to being able to be used as a conductor path, it also has the advantage of printing and co-firing resistive materials. Porcelain materials for such low-temperature firing include alumina with a large amount of glass added, but the resulting porcelain contains many pores, and migration between conductor paths occurs through the pores. I can see the problem occurring. In addition, there is also BaSnO ₃ with a large amount of boron added, but the calcined product becomes glassy, which not only makes it difficult to crush the calcined product.
Boron evaporates rapidly, which caused problems such as reacting with conductive materials when fired simultaneously and damaging the furnace material for firing. (Object of the invention) Therefore, an object of the present invention is to provide a porcelain composition that can be fired at 1000°C or lower. Another object of the present invention is to provide a porcelain composition that is easy to process, such as pulverization, in its manufacturing process. A further object of the present invention is to provide a ceramic composition that has high electrical resistivity, low dielectric constant, and low dielectric loss. Furthermore, an object of the present invention is to provide a ceramic composition suitable for a multilayer ceramic substrate, although it is not particularly limited thereto. (Structure of the Invention) The porcelain composition for low-temperature firing according to the present invention can be summarized as consisting of the following constituent materials () to (). () ( _{Ba 1 - X M} or 2 types 0≦x≦0.3, 0≦y≦0.3, 0≦x+y≦0.3 ()SiO ₂ is 35 to 65 mol% () B ₂ O ₃ is 4 to 25 mol% () Al ₂ O ₃ is 2 ~10 mol% () At least one of Li ₂ O, Na ₂ O, and K ₂ O is 10 mol % or less (not including 0) () 2 to 10 mol of one or two of BaO and CaO % The composition ranges listed above are limited to the following. That is, (Ba _1-X M _X ) (Ti _iy M
_y ) If the O ₃ content is less than 20 mol %, the firing temperature will exceed 1000°C, while if it exceeds 40 mol %, the dielectric constant will increase. Furthermore, x and y of M _x and M _y were defined as 0≦x≦0.3, 0≦y≦0.3, and 0≦x+y≦0.3, respectively. Therefore (Ba _1-X M _X ) (Ti _1-y M
_y ) _O3 , when x=0, y=0
In addition to BaTiO ₃ , (Ba, Ca) TiO ₃ , (Ba, Ca)
(Ti,Zr) _O3 , (Ba,Sr) _TiO3 , (Ba,Sr)
(Ti, Sn)O ₃ , (Ba, Sr, Ca, Mg) (Ti, Sn)
Contains components such as _O3 . Here, the upper limit values of x, y, and x+y are set to 0.3 or less because as the amounts of x, y, and x+y increase,
Firing temperature tends to rise, especially x, yx+
This is because if y exceeds 0.3, the firing temperature will exceed 1000°C. The reason why SiO ₂ is set at 35 to 65 mol % is that if it is less than 35 mol % or exceeds 65 mol %, the firing temperature becomes high. The reason why B ₂ O is set at 4 to 25 mol % is that if it is less than 4 mol %, the sintering temperature becomes high, and if it exceeds 25 mol %, welding of sintered porcelain tends to occur. The reason why Al ₂ O ₃ is set at 2 to 10 mol % is because if it is less than 2 mol % or exceeds 10 mol %, the firing temperature becomes high. The reason why at least one of Li ₂ O, Na ₂ O, and K ₂ O is 10 mol% or less (excluding 0) is 10
This is because if the amount exceeds mol %, welding of porcelain pieces to each other tends to occur. The reason why one or both of BaO and CaO is set at 2 to 10 mol % is because if the content is less than 2 mol % or exceeds 10 mol %, the sintering temperature becomes high. In addition, (Ba _1-x M _x ) (Ti _1-y M _y ) O ₃ is ABO ₃
Although this invention is expressed as a perovskite type composition consisting of A and B, changing the ratio (molar ratio) of A and B within a range that does not impair the characteristics is also included in the present invention. (Examples) Hereinafter, the present invention will be described in detail based on Examples. Example 1 As raw materials, BaCO ₃ , CaCO ₃ , SrCO ₃ ,
MgCO ₃ , TiO ₂ , ZrO ₂ , and SnO ₂ were prepared and weighed to give the composition ratios shown in Table 1. After mixing the weighed raw materials, they were calcined at 1150°C. Next, these calcined powders and SiO ₂ , B ₄ C, Al ₂ O ₃ , Li ₂ CO ₃ , K ₂ CO ₃ ,
Raw materials Na ₂ CO ₃ Ba ₂ CO ₃ , BaCO ₃ , and CaCO ₃ were weighed so as to obtain porcelain having the composition ratios shown in Table 1. The weighed raw materials were mixed and crushed, a binder was added, and the mixture was formed into a disk shape. Molded body in air 850~950
Porcelain was created by firing at ℃. Specific resistance, dielectric constant, dielectric loss, and bending strength were measured for each piece of porcelain. The measurement conditions for each characteristic are as follows. Specific resistance: DC1.5V Dielectric constant: 1MHz Dielectric loss: 1MHz Breaking strength: According to JIS standards Table 2 shows the measurement results of various properties of each ceramic.

【table】

【table】

[Table] Items marked with * in Tables 1 and 2 are outside the scope of this invention, and the others are within the scope of this invention. Example 2 As raw materials, BaCO ₃ , CaCO ₃ , SrCO ₃ ,
_MgCO3 , _TiO2 , _ZrO2 , _SnO2 , _SiO2 , _B4C ,
Al ₂ O ₃ , Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , BaCO ₃ ,
CaCO ₃ was prepared and weighed so as to obtain porcelain having the composition ratio shown in Table 1 of Example 1. After mixing the weighed raw materials, they were calcined at 850 to 950°C. After pulverizing the calcined product, an organic binder was added and the product was formed into a sheet using a doctor blade method. The obtained ceramic green sheet was cut into a predetermined size and fired in air at 850 to 950°C to obtain a porcelain plate. Regarding the obtained porcelain plate, various properties were measured under the same measurement conditions as in Example 1.
The results showed almost the same characteristics as those shown in Table 2. Furthermore, using the ceramic green sheet obtained in the above process, a silver paste containing lead borosilicate glass frit was printed on the surface of the sheet, three sheets were stacked and thermocompression bonded, and the sheets were heated at 850°C in air.
Calcined at ~950°C. When the reaction between the porcelain and silver was analyzed for the obtained multilayer porcelain substrate, it was found that the one according to the present invention
No reaction was observed between the two, and silver showed good conductivity. Example 3 Using each of the ceramic green sheets prepared in Example 2, the binder was fired at 400°C, and then fired in nitrogen at 840-950°C for 1 hour to obtain porcelain. When the specific resistance of each porcelain according to the present invention was measured, the specific resistance was 10 ¹³ to 10 ¹⁴ depending on the sample.
Although there were some cases where the resistance decreased to Ω・cm, it was confirmed that there was no problem in practical use. Therefore, as an internal conductor of a multilayer ceramic substrate,
For example, when using Cu, etc., the atmosphere for simultaneous firing must be set to a neutral or reducing atmosphere, but it has been found that porcelain has sufficient insulating properties for practical use even when fired in these atmospheres. . Note that in the above examples, SiO ₂ , Al ₂ O ₃ , CaO
However, compounds such as carion (Al ₂ O ₃・2SiO ₂・2H ₂ O) and wollastonite (CaSiO ₃ ) were added so that each of these components existed within the composition range of this invention. It may also be used as a raw material. (Effects of the Invention) As is clear from the above description, according to the present invention, sintered porcelain can be obtained by firing at a low temperature of 1000°C or less, and operations such as crushing in the manufacturing process can be easily performed. Additionally, it has high specific resistance, low dielectric constant, and low dielectric loss. Furthermore, when used as a multilayer ceramic substrate, no reaction with the internal conductor was observed during simultaneous firing. Furthermore, since the porcelain has few pores, it has the advantage that migration between internal conductors does not occur. Further, even when fired in a neutral or reducing atmosphere, no decrease in specific resistance is observed, and base metals such as Cu and Ni can be used as the internal conductor.

Claims (1)

[Claims] 1st-order composition (), (), (), (), ()
,
A porcelain composition for low temperature firing consisting of (). ( ₎ (Ba _{1 - X M} 2
seed. 0≦x≦0.3, 0≦y≦0.3, 0≦x+y≦0.3 ()35 to 65 mol% of SiO ₂ ()4 to 25 mol% of B ₂ O ₃ () 2 to 20 mol of Al ₂ O ₃ % () At least one of Li ₂ O, Na ₂ O, and K ₂ O is 10 mol % or less (not including 0) () 2 to 10 mol % of one or two of BaO and CaO.