JPH0225863B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a ceramic composition that is a material for a circuit board,
In particular, the present invention relates to a ceramic composition suitable as a material for multilayer circuit boards. [Prior Art] Today, there is a demand for miniaturization of electric circuit devices, and there is a tendency for circuit boards to become increasingly multi-layered, smaller, thinner, and have higher integration density. In order to obtain high reliability under these circumstances, porcelain, which has various properties such as high insulation and high bending strength, is used as a material for multilayer circuit boards. In addition, in order to reduce the manufacturing cost of multilayer circuit boards, it has been necessary to use a low firing temperature and a non-oxidizing atmosphere so that relatively inexpensive conductive materials (such as base metals such as nickel) can be used for wiring. A firing method was tried. Furthermore, as the substrate becomes thinner, the wiring pattern of the internal circuit becomes easier to see through from the outside, so a porcelain material with high light-shielding properties is required from the viewpoint of security. [Problems to be Solved by the Invention] However, many of the porcelains fired in a non-oxidizing atmosphere have a characteristic of having low light-shielding properties after firing. One way to improve light-shielding properties is to use ceramic substrate materials.
There is a method of adding oxides such as CuO, Pb ₂ O ₃ and V ₂ O ₅ . However, if porcelain to which these are added is fired in a non-oxidizing atmosphere, there is a drawback that the insulation resistance value of the porcelain becomes low. The present invention was made to solve the above-mentioned problems with conventional porcelain materials, and an object of the present invention is to provide a porcelain composition that has high light-shielding properties and high insulation properties. [Means for solving the problem] The ceramic composition of the present invention contains 0.5 to 10 mol% of _Li2O .
5 to 45 mol% of components consisting of one or more of CaO, SrO, BaO, and ZnO, and 1 to 40.7 mol% of MgO.
and 1 to 40 mol% of _Al2O3 , 1 to 30.3 mol% of _ZrO2 , 12.8 to 65.6 mol% of _SiO2 , and _0.3 mol _% of _Cr2O3 .
It is obtained by firing a mixture containing 7% by mole in a non-oxidizing atmosphere. [Example] Below, as an example of the present invention, samples were prepared from porcelain compositions having different contents of each component, and test results and the like conducted for each sample will be described. First, using Sample 1 as an example, we will explain the preparation method and conditions for the samples listed in the attached table.
50.3 g of SiO ₂ powder, 24.5 g of CaCO ₃ powder, 3.0 g of MgO powder, 1.7 g of ZrO ₂ powder, 5.9 g of Al ₂ O ₃ powder
Weigh 10.3 g of Li ₂ CO ₃ powder and 4.3 g of Cr ₂ O ₃ powder. Note that the above Ca and Li carbonate powders were both stable in air. Place each weighed powder in a ball mill, approximately 15
Wet mixed by ball milling for an hour. Next, 12% by weight of acrylic resin, 0.5% by weight of allylsulfonic acid, and 30% by weight of water were added to the same material and stirred to prepare a slurry. Next, a long unsintered porcelain sheet was made from this slurry by a doctor blade method, and this was cut into 10 cm square pieces. Three types of samples were prepared from the cut unsintered porcelain sheets according to the purpose of the test. In other words, ^a diameter
A disk-shaped sample punched out with a 1.6 cm piece, a prismatic sample made by cutting a 0.2 cm thick plate made by laminating 12 of the above sheets into 3.6 cm length and 0.4 cm width, and the above. Cut the sheet into 5cm long and 3cm wide pieces, and apply Ni paste to the center of one side to a length of 3cm.
A plurality of rectangular plate-shaped samples were prepared by screen-printing five straight lines with a width of 0.03 cm and a width of 0.03 cm in parallel at intervals of 0.05 cm. These samples were then heated in air to 600°C at a rate of 100°C per hour to burn off the binder components such as acrylic resin. After that, inside the furnace
The atmosphere was changed to a reducing atmosphere containing 97.0% by volume of N ₂ and 3.0% by volume of H ₂ , and the temperature was maintained at 1000°C for 3 hours for firing.
Sample 1 was obtained. The above firing temperature FT at this time is shown in the separate table. This sample was then tested in the following manner. First, regarding the electrical characteristics, we used the disk-shaped sample mentioned above, and indium was coated on both sides of the sample.
A gallium alloy was applied, an electrode with a diameter of 1.4 cm was provided, and the dielectric constant ε, quality factor Q, and resistivity ρ (Ωcm) were measured. The relative permittivity ε is 25℃
Q was calculated from the capacitance measured at a frequency of 1 MHz at a temperature of Further, the resistivity ρ was calculated from the insulation resistance value 60 seconds after applying a DC voltage of 500V. Regarding the physical and mechanical properties, a prismatic sample with a thickness of 0.2 cm was used, and the coefficient of thermal expansion and bending strength τ
was measured and shown in the attached table. The coefficient of thermal expansion is
Linear expansion coefficient α (/℃) between 20 and 500℃
The bending strength τ was measured according to the three-point bending strength of JIS-R1601. Furthermore, for light shielding, we pre-coated one side with Ni.
A rectangular plate-shaped sample with lines drawn on it was used. If these lines were not visible to the naked eye from the back side, the light-shielding property was good, and if they were visible, the light-shielding property was poor. Hereinafter, for Samples 2 to 78, each porcelain material powder was prepared so that the composition of the porcelain would have the content ratio as shown in each column of the attached table, and was produced from this in the same manner and under the same conditions as Sample 1 above. However, the firing temperature FT is
Each test was conducted at a different temperature as shown in each column of the attached table. In addition, for each sample made in this way, the above-mentioned properties were measured using the same method and conditions as Sample 1, and the linear expansion coefficient α, bending strength τ, resistivity ρ, and light shielding properties of each sample were shown in the attached table. shown in each column. In addition, all the numerical values showed the average value of the measured value obtained about several samples. As is clear from the same table, all of these samples 1 to 78 have a firing temperature FT of 1250°C or lower, a linear expansion coefficient α of 6.5×10 ^-6 /°C or lower, and a bending strength τ of 1500°C.
Kg/cm ² or more, the resistivity ρ was 1×10 ¹³ Ωcm or more, and the light shielding properties were good in all cases. Note that these samples all have a relative dielectric constant ε of 9 or less and a Q of
500 to 2000, which is a practical value for circuit board materials. Please note that these specific figures have been omitted from being listed in the attached table. [Comparative Example] On the other hand, 13 samples No. 79 to No. 91 were prepared using a porcelain material that did not meet the above content ratio requirements and using the same method and conditions as the above sample. However, the firing temperature FT was different for each, and the firing was performed at the temperatures shown in each column of the separate table. Note that there are some products that cannot be sintered in a general industrial kiln because the temperature range for sintering is narrow, and these are shown in the attached table. In addition, each sample made in this way was tested in the same manner and under the same conditions as above, and the linear expansion coefficient α, bending strength τ, resistivity ρ, and light shielding properties are shown in the attached table. [Function] The reason why the components of the porcelain composition according to the present invention are limited as described above is generally as follows. (1) If the SiO ₂ content is too low, the firing temperature FT will become high, and if it is too high, the same temperature FT will become high. For example, the content of SiO ₂ in samples 1 to 78 is
Sample 70 had the lowest content of 12.8 mol%, but this could be sintered at 1250°C, while sample 79, which had a lower content of 10.0 mol%,
Sintering required a temperature of 1300℃. On the other hand, sample 1~
Samples 1, 5, 13, 16, 32, 44, and 78 have a relatively high SiO ₂ content of 60.0 to 65.6 mol%.
55, 73, 74, but all of these are 1000~
Sample 80 containing a higher content of 68.0 mol% _SiO2 could be sintered at a temperature of 1200℃.
Sintering required a temperature of 1300℃. (2) If the content of one or more of CaO, SrO, BaO, and ZnO is too small, the sintering temperature will be high, and if it is too large, the range of temperatures that can be sintered will be narrowed. For example, among samples 1 to 78, samples 12, 14,
16-20, 22, 44, and 48, but these could all be sintered at a temperature of 1100-1150℃,
Sample with low content of the above oxides at 3.0 mol%
81 required a temperature of 1300°C for sintering. on the other hand,
Among samples 1 to 78, samples 29, 52, 77, and 78 have a relatively large amount of the above oxides at 41.1 to 45.0 mol%.
Sintering was possible at a temperature of 950 to 1050°C, but when the content increases to 50.0 mol%, as in sample 82, the range of temperatures that can be sintered becomes narrower, and sintering cannot be performed in a general industrial sintering furnace. I couldn't let it go. (3) If the MgO content is too low, the range of temperatures that can be sintered will be narrowed, and if it is too high, the sintering temperature FT will increase and the insulation properties will decrease. For example, MgO is 1.0 mol% in samples 1 to 78.
The least common ones are 2, 3, 7-10, 13-15,
19, 21, 26, 28, 30, 32, 34-36, 46, 50,
Samples 55, 57, 59, 73, 77, and 78 were all able to be sintered at a temperature of 950 to 1200°C, whereas sample 83 containing 0.1 mol% MgO was lower than this temperature. In this case, the range of temperatures that can be sintered is narrow,
It was not possible to sinter it in a general industrial kiln. On the other hand, among samples 1 to 78, 33.2 to 40.7
The sample has a relatively high mole% content.
18, 56, 70, but all of these are 1150 ~
While sintering was possible at a temperature of 1250°C, sample 84 containing 45.0 mol% of MgO required a temperature of 1350°C for sintering. Moreover, the resistivity ρ of the former was 1×10 ¹³ Ωcm or more, whereas the resistivity ρ of the latter was as low as 1×10 ¹¹ Ωcm. (4) Al ₂ O ₃ has excellent mechanical strength, and when the amount is large, the bending strength is high, but on the other hand, when it is too large, the firing temperature FT becomes high. For example, this content is 31.6 among samples 1 to 78.
Samples 19, 23, 49, 57, and 70, which had a relatively large amount of ~40.0, had a high bending strength of 2400 to 2600 Kg/cm ² and could be sintered at a temperature of 1150 to 1250°C. However, in sample 85 containing more Al ₂ O ₃ (45.0 mol%), the bending strength was 2500.
Kg/cm ² and there was no tendency to improve, and sintering required a temperature of 1300°C. (5) When the content of ZrO ₂ is low, the insulation property decreases,
If this amount is too large, the firing temperature FT will become high. For example, _ZrO2 is 1.0 mol% in samples 1 to 78.
and the least is 1, 2, 4, 6, 7, 9,
12, 13, 16, 17, 21, 23, 27, 29, 31-33, 36
~38, 49, 52, 56, 57, 60, 61, 65, 70, 74,
Samples such as No. 76 had a resistivity ρ of 1×10 ^{13 Ωcm or more, whereas sample 86 with a content of 0.1 mol% or less had a resistivity ρ of 1×10 13} Ωcm or more.
was 1×10 ¹¹ Ωcm. In addition, among samples 1 to 78, samples 20 and 58, which have a relatively high _ZrO2 content of 25.0 to 30.3 mol%, could be sintered at a temperature of 1150 to 1200°C, whereas 33.0 mol% of ZrO2 Sample 87 with a content of (6) Too little Li ₂ O increases the coefficient of thermal expansion, while too much Li 2 O decreases the insulation properties. For example, in samples 1 to 78, 0.5 to 0.9 mol%
The relatively low content of Li ₂ O is 53, 58,
Samples 64, 67, and 77 all have linear expansion coefficients α of 5.8 to 6.5×10 ^-6 /°C, whereas sample 88 has a content of 0.2 mol%, which is lower than these. Then, the linear expansion coefficient α is 7.2×
The temperature is rising to 10 ^-6 /℃. On the other hand, samples 1 to 87
1, 9, 22, which have relatively high Li ₂ O content among
For samples such as No. 24, the resistivity ρ is 1×10 ¹³ Ω.
cm or more, the same content is 12.0 mol%
Sample 89 had a low resistivity ρ of 1×10 ¹¹ Ωcm. (7) If the content of Cr ₂ O ₃ is too low, good light-shielding properties cannot be obtained, and on the other hand, if it is too high, the resistivity decreases,
The bending strength also decreases. For example, sample 1 has a Cr ₂ O ₃ content of 0.3 mol%.
For samples 14, 15, 44, 56 etc., which are the smallest among ~78, the sintering temperature is 1150~1250℃, and the bending strength is
It was 1700 to 1900 Kg/cm ² and had good light shielding properties, but in sample 90, which had a small amount of 0.1 mol%,
The light shielding property became poor. In addition, among samples 1 to 78, samples 25, 55, 57, 62, and 67, which have a relatively high Cr ₂ O ₃ content of 5 to 7 mol%, all have resistivities ρ of 1 × 10 ¹³ Ωcm or more. , bending strength is 2300~2600
Kg/cm ² , but in sample 91 with 12 mol %, the resistivity ρ was as low as 1×10 ¹¹ Ωcm, and the bending strength was also as low as 1500 Kg/cm ² . [Effects of the Invention] As explained above, the porcelain composition according to the present invention can be sintered at a relatively low temperature of 1250°C or less in a non-oxidizing atmosphere, and at the same time has high light-shielding properties, and is suitable for practical use. Moreover, sufficient insulation resistance can be obtained. Therefore, it is possible to manufacture the board at low cost, and it is also possible to respond to thinning of the board, and it is possible to maintain the confidentiality of the wiring pattern even in the thinned board.

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Claims (1)

[Claims] 1 0.5 to 10 mol% of Li ₂ O, CaO, SrO, BaO,
5 to 45 mol% of a component consisting of one or more types of ZnO,
1 to 40.7 mol% MgO and 1 to 40 mol% Al ₂ O ₃
, ZrO ₂ from 1 to 30.3 mol%, and SiO ₂ from 12.8 to 65.6 mol%.
A porcelain composition comprising _0.3 to 7 mol% of _Cr2O3 .