JPH0220583B2 - - 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 20 to 70% Al ₂ O ₃ (weight ratio, same hereinafter), 10 to 55% SiO ₂ , CaO,
1 to 1 component consisting of one or more of SrO, BaO, ZnO
40%, B ₂ O ₂ 3-30%, Li ₂ O 0.1-3%
and 0.5 to 10% Cr ₂ O ₃ . [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 each sample listed in the attached table.
40.0g Al ₂ O ₃ powder, 10.0g SiO ₂ powder, 17.8g CaCO ₃ powder, 6.32g BaCO ₃ powder, Li ₂ CO ₃ powder
Weigh out 0.25 g, 30 g of B ₂ O ₃ , and 5.0 g of Cr ₂ O ₃ powder. The Ca, Ba, and Li carbonate powders used were all stable in the 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 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 0, and the temperature was maintained at 1150° C. for 3 hours to obtain Sample 1. The above firing temperature FT at this time
are shown in the attached 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 applied to 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, regarding light-shielding properties, we used a rectangular plate-shaped sample with five straight lines drawn on one side of Ni.If these lines cannot be seen through to the naked eye from the back side, the light-shielding properties are considered to be good, and if these lines are visible from the back side, light-shielding properties are considered good. It was considered a sexual defect. Hereinafter, for Samples 2 to 53, each porcelain material powder was prepared so that the composition of the porcelain had a content ratio as shown in each column of the attached table, and was produced from this powder 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 among these, the bending strength τ, linear expansion coefficient α, and light shielding property of each sample were measured as shown in the attached table. Shown in the 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 53 have a firing temperature FT of 1250°C or lower, a bending strength τ of 1500 Kg/cm ² or higher, and a linear expansion coefficient α of 6.0×
10 ^-6 /°C or less, and the light shielding properties were all good. These samples all have a relative dielectric constant ε of 9 or less, a Q of 500 to 2000, and a resistivity ρ of 1×
It was 10 ¹³ Ωcm or more, which is a value that is practical for use as a circuit board material. Please note that these specific figures have been omitted from being listed in the attached table. [Comparative Example] On the other hand, 10 samples Nos. 54 to 63 were prepared using a porcelain material that did not meet the requirements for the content ratio described above 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 and light shielding properties are shown in the attached table. Further, the resistivity ρ was 10 ¹³ Ωcm or more in all samples except Samples 59 and 63, which were 10 ¹² Ωcm. [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 content of SiO ₂ is less than 10%, the firing temperature
When FT becomes high and exceeds 55%, FT at the same temperature becomes high. For example, the content of SiO ₂ in samples 1 to 53 is
Samples 1 to 6 have the lowest content of 10.0%, but while all of these samples were able to sinter at 1150 to 1250°C, sample 54, which had a lower content of 5.0%, could not be sintered. It required a temperature of 1350℃. On the other hand, the content of SiO ₂ in samples 1 to 53 is
The most common sample, 55%, is 10 to 15 samples.
All of these could be sintered at temperatures below 1150°C, whereas sample 55, which contained a higher content of 65% SiO ₂ , required a temperature of 1300°C for sintering. (2) If the content of one or more of CaO, SrO, BaO, and ZnO is more than 40%, the firing temperature FT increases. For example, among samples 1 to 53, samples 16 (40%) and 29 (36.9%) have a relatively high content of these oxides.
%), it was possible to sinter at 1100°C and 1200°C, respectively, but when the content was even higher to 50%, as in sample 56, the firing temperature FT became as high as 1300°C. (3) If the content of Al ₂ O ₃ is less than 20%, the range of temperatures that can be sintered will be narrowed, and if it is more than 70%, the firing temperature FT will be high. For example, samples with an Al ₂ O ₃ content of 20%, such as Samples 13 to 18, yielded sintered bodies that could be used as porcelain in a general industrial firing furnace; Sample 57 had a narrow range of temperatures that could be sintered, and could not be sintered in a general industrial kiln. On the other hand, in samples with Al ₂ O ₃ content of 70% like Samples 4 to 9, all
Whereas sintering was possible at 1150-1250℃, this
Sample 58 of % required a high firing temperature FT of 1400°C. (4) If the content of B ₂ O ₃ is less than 3%, the firing temperature
It is necessary to increase FT, and if it is more than 30%, the range of temperatures that can be sintered becomes narrower. For example, sample 8 with a B ₂ O ₃ content of 3%,
In the case of 27 and 38, it was possible to sinter at a firing temperature of 1150 to 1250°C, but this was the case for the 1% sample.
60 required a temperature of 1350°C for sintering. Also,
Among samples 1 to 53, samples 1 (30%) and 20 (26.5%), which have a relatively high B ₂ O ₃ content, were able to produce sintered bodies that could be used as porcelain in a general industrial firing furnace. On the other hand, a sample with a content of 40%, such as Sample 61, could not be sintered in a general industrial kiln because the temperature range at which it could be sintered was narrow. (5) If the LiO ₂ content is more than 3%, sufficient insulation resistance cannot be obtained. For example, as mentioned above, all of the samples other than sample 59, which contains 5% LiO ₂ , had a resistivity ρ of 10 ¹³ Ωcm or more, but in sample 59,
The resistivity ρ was as low as 10 ¹² Ωcm. (6) If the Cr ₂ O ₃ content is less than 0.5%, good light shielding properties cannot be obtained, and if it is more than 10%, the resistivity ρ
decreases, and the bending strength also decreases. For example, sample 4 with a Cr ₂ O ₃ content of 0.5%,
Samples No. 8, 9, 16, 31, and 36 had good light-shielding properties, but Sample 62, which had a small amount of 0.2%, had poor light-shielding properties. In addition, the content of Cr ₂ O ₃ is 10
The following samples 1 to 53 all have a resistivity ρ of 10 ¹³ Ω.
cm or more, but in sample 63 where this was 15%,
Low resistivity ρ of 10 ¹² Ωcm and bending strength
It was as low as 1300Kg/ ^cm2 . [Effects of the Invention] As explained above, the porcelain composition according to the present invention can be sintered at a low temperature of 1250°C or less in a non-oxidizing atmosphere, and at the same time has a high light-shielding property, which is sufficient for practical use. A high insulation resistance can be obtained. Therefore, the ceramic substrate can be manufactured at a relatively low cost, the substrate can be made thinner, and the confidentiality of the wiring pattern can be maintained.

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Claims (1)

[Claims] 1 20 to 70% by weight of Al ₂ O ₃ , 10 to 55% by weight of SiO ₂ , 1 to 40% by weight of a component consisting of one or more of CaO, SrO, BaO, and ZnO, and 3% by weight of B ₂ O ₂ ~30% by weight
, 0.1 to 3% by weight of Li ₂ O, and 0.5 to 10% by weight of Cr ₂ O ₃ .