JP4419487B2 - Oxide porcelain composition, ceramic multilayer substrate and ceramic electronic component - Google Patents

Description

  The present invention relates to an insulating oxide ceramic composition used for ceramic multilayer substrates, ceramic electronic components, and the like.

Conventionally, BaO—Al ₂ O ₃ —SiO ₂ -based oxide porcelain compositions have been known as insulator materials used for ceramic multilayer substrates and ceramic electronic components. Patent Document 1 discloses that each of Si, Ba, Al, B, Cr, and Ca is used as an oxide ceramic composition that can be fired at a low temperature, has a wide firing temperature range, and has a high insulation resistance and a low relative dielectric constant. A porcelain composition comprising an oxide is disclosed.
Japanese Patent Laid-Open No. 4-16551

  However, with the progress of miniaturization of electric circuit devices in which ceramic multilayer substrates and ceramic electronic components are incorporated, oxide ceramics that can withstand and are required to be reduced in size and thickness for ceramic multilayer substrates and ceramic electronic components. The bending strength of the composition is required.

  In general, the bending strength of a ceramic greatly depends on its composition. However, the porcelain composition disclosed in Patent Document 1 has a bending strength of less than 200 MPa when used as a substrate. In some cases, cracks may occur, and the market demands could not be fully satisfied.

Accordingly, an object of the present invention is to improve the bending strength of multilayer substrates and electronic parts using a BaO—Al ₂ O ₃ —SiO ₂ based ceramic composition, and to reduce the size and thickness of multilayer substrates and electronic components. An object of the present invention is to provide an oxide porcelain composition capable of enhancing the reliability of a component, a ceramic multilayer substrate and a ceramic electronic component using the same.

In order to achieve the above object, the oxide ceramic composition of the present invention is a powdered oxide ceramic composition containing Al, Si, Ba, B and Cr as metal elements, wherein Al is Al ₂ O _3. in terms of 11.5 to 14.0 wt%, 54.0 to 70.0 wt% in terms of Si to SiO _2, 4.0 to 30.0 wt% in terms of Ba to BaO, B In an amount of 1.0 to 10.0% by weight in terms of B ₂ O ₃ and 0.3 to 3.0% by weight in terms of Cr in terms of Cr ₂ O ₃ , and further 100 parts by weight of these main components On the other hand, at least one selected from CaO, MgO, ZnO and SrO as a subcomponent is contained in a total amount of 3 parts by weight or less , and the average particle size is 1.5 μm or less .

  Furthermore, the ceramic multilayer substrate of the present invention is a ceramic multilayer substrate comprising a ceramic laminate and an internal conductor formed between the ceramic layers of the ceramic laminate, wherein the ceramic layer comprises the oxide ceramic composition described above. It consists of things.

  The ceramic electronic component of the present invention is a ceramic electronic component comprising a ceramic body, an internal conductor formed inside the ceramic body, and an external electrode formed on the surface of the ceramic body, The ceramic body is composed of the above-described oxide ceramic composition.

  Furthermore, the ceramic electronic component of the present invention is characterized in that the inner conductor and the outer electrode are mainly composed of copper.

According to the present invention, it is possible to improve the bending strength of the multilayer circuit board and an electronic component using a BaO-Al ₂ O ₃ -SiO ₂ based oxide ceramic compositions.

  In addition, a Q value of 1000 or more and good solderability can be obtained, and the reliability of multilayer circuit boards and electronic components that are becoming smaller and thinner can be improved. Furthermore, since the range of the firing possible temperature range is widened, defects due to temperature fluctuations and variations in the firing furnace are less likely to occur, and mass productivity is improved.

First, SiO ₂ , BaCO ₃ , Al ₂ O ₃ , B ₂ O ₃ and Cr ₂ O ₃ each having a particle size of 2.0 μm or less were prepared as starting materials.

  Next, it prepared and mixed so that the oxide ceramic composition of the composition ratio shown in Table 1 might be obtained, and calcined at 800-1000 degreeC. The obtained calcined product was pulverized with a zirconia ball mill for 12 hours to obtain a raw material powder.

  To this raw material powder, polyvinyl butyral as an organic binder, DOP as a plasticizer, and a solvent containing toluene as main components were added, mixed with a ball mill, and defoamed under reduced pressure to prepare a slurry. It is preferable to adjust the pulverization time of the raw material powder so that the average particle size of the powder in the slurry is 1.5 μm or less. By setting the average particle size of the powder in the slurry to 1.5 μm or less, the firing temperature can be lowered.

  The obtained slurry was formed as a 1 mm thick green sheet on the film by the doctor blade method, and then the film was peeled and cut into a predetermined shape. And it baked at 950-1040 degreeC in the non-oxidizing atmosphere of nitrogen-hydrogen, and obtained the plate-shaped porcelain sample.

  Thereafter, a paste prepared by mixing copper powder and an organic vehicle as an electrode at a weight ratio of 80:20 was printed on the front and back surfaces of the porcelain sample. Then, it baked in 950-1040 degreeC in the non-oxidizing atmosphere of nitrogen-hydrogen, and the sample to which the copper electrode was provided was obtained.

  Next, the bending strength of the obtained sample was measured by a three-point bending strength test (JIS R1601).

  Further, as electrical characteristics, the capacitance and Q at a frequency of 1 MHz and the insulation resistance at DC 100 V were measured, and εr (relative dielectric constant) was calculated from the capacitance.

  Further, in order to examine the solderability of the sample, the sample was preheated for 20 seconds in advance, and a chlorine-based flux was applied to the surface of the copper electrode, and then the sample was placed in a 230 ° C. solder bath (Sn / Pb = 6/4 weight ratio). It was immersed for 2 seconds and soldered. Then, the surface of the copper electrode is visually observed, and when 90% or more of the copper electrode surface is covered with solder, the solderability is good, and when less than 90%, the solderability is poor. did.

These results are shown in Table 1. In Table 1, those marked with ◯ in the solderability column have good solderability, and those marked with x have poor solderability. In Table 1, the sample numbers marked with * are outside the scope of the present invention.

As is apparent from Table 1, Al is converted to Al ₂ O ₃ in an amount of 11.5 to 60.0% by weight, Si is converted into SiO ₂ in an amount of 4.0 to 70.0% by weight, and Ba is converted into BaO. Convert to 4.0 to 40.0% by weight, in terms of 1.0 to 30.0 wt% in terms of B to B ₂ O _3, and Cr in the Cr ₂ O ₃ 0.3 to 3. The oxide porcelain composition containing 0% by weight exhibits an excellent bending strength of 200 MPa or more. Moreover, Q shows 1000 or more and is excellent in solderability.

On the other hand, when the Al ₂ O ₃ content is less than 11.5% by weight as shown in Samples 1 and 2, or when it exceeds 60.0% by weight as shown in Sample 30, the bending strength is less than 200 MPa. And low.

The bending strength changes depending on the content of Al ₂ O ₃ due to the precipitation of the Al compound. If the content of Al ₂ O ₃ is less than 11.5% by weight, the Al compound is sufficiently analyzed. Since it does not come out, the bending strength is as low as less than 200 MPa. On the other hand, if the Al ₂ O ₃ content exceeds 60.0% by weight, the sinterability deteriorates and the ceramic sintered body is not sufficiently densified, so that the bending strength is reduced to less than 200 MPa.

Further, as shown in Samples 28 and 6, when SiO ₂ is less than 4.0% by weight or more than 70.0% by weight, the sinterability is deteriorated and the sintered body is not sufficiently densified. Is less than 1000.

  Further, as shown in Samples 22 and 10, when BaO is less than 4.0% by weight or exceeds 40.0% by weight, the sinterability deteriorates and the sintered body becomes difficult to be sufficiently densified, and Q is Less than 1000.

Further, as shown in Sample 4, when B ₂ O ₃ is less than 1.0% by weight, the sinterability is deteriorated and the porcelain sintered body is hardly sufficiently densified, and Q is less than 1000. On the other hand, as shown in Sample 27, when B ₂ O ₃ exceeds 30.0% by weight, the amorphous phase increases and Q becomes less than 1000.

Further, as shown in Samples 15 and 13, when Cr ₂ O ₃ is less than 0.3% by weight or more than 3.0% by weight, solderability is slightly deteriorated. In addition, when the glass phase is raised on the surface of the electrode during firing, the solderability is deteriorated, but Cr has an effect of preventing the flow of the glass phase, and the deterioration of the solderability can be prevented.

As starting materials, the same SiO ₂ , BaCO ₃ , Al ₂ O ₃ , B ₂ O ₃ and Cr ₂ O ₃ as in Example 1 were prepared. Also, CaCO ₃ , Mg (OH) ₂ , ZnO and SrCO ₃ having a particle size of 2.0 μm or less were prepared.

  Thereafter, in the same manner as in Example 1, ceramic samples having the composition ratios shown in Table 2 were obtained. During firing, the firing temperature was varied for samples having the same composition, and the firing possible temperature range was determined.

  Generally, the firing shrinkage behavior during ceramic firing tends to increase as the firing temperature increases up to a certain temperature, takes a maximum value at a certain temperature, and then decreases. In the present invention, the temperature at which the firing shrinkage rate takes the maximum value is the optimum firing temperature of the sample, and the temperature range where the difference from the maximum shrinkage rate is within 0.5% is the firing possible temperature range, The parameter was set to indicate easy sinterability.

The results are shown in Table 2. In Table 2, the sample numbers marked with ◎ are within the scope of the present invention.

  As is apparent from Table 2, the inclusion of at least one selected from CaO, MgO, ZnO and SrO as subcomponents in a total amount of 3 parts by weight or less widens the sinterable temperature range and facilitates sintering. Become. On the other hand, as shown in samples 35 and 41, those containing at least one selected from CaO, MgO, ZnO and SrO in a total amount exceeding 3 parts by weight increase the firing temperature to around 1000 ° C. And the width of the sinterable temperature range is not much different from that in the case where the oxide is not added (sample 31).

  The same raw material as in Example 1 was prepared as a starting raw material. Thereafter, in the same manner as in Example 1, the mixture was prepared so that a ceramic composition having the composition ratio shown in Sample 8 of Table 1 was obtained, the slurry was adjusted, and a green sheet was obtained.

  Thereafter, the green sheet was cut into a predetermined dimension, and a conductor pattern mainly composed of Cu was formed on the surfaces of the cut green sheets by a screen printing method. Via holes were formed in the plurality of green sheets on which the conductor pattern was formed using a puncher, and a conductor mainly composed of Cu was filled. The conductor patterns on the surface of each green sheet were stacked and crimped so that they could be electrically connected to each other. This green sheet pressure-bonded body was fired at 980 ° C. in a non-oxidizing atmosphere of nitrogen-hydrogen.

  As a result, as shown in FIG. 1, a ceramic multilayer substrate including a ceramic layer 1 and an internal conductor 3 electrically connected by a via hole 2 was obtained.

  Next, when the bending strength of the obtained ceramic multilayer substrate was measured in the same manner as in Example 1, an excellent bending strength of 200 MPa or more was obtained.

  FIG. 2 is a perspective view of a multilayer inductor 11 which is an embodiment of the ceramic electronic component of the present invention. FIG. 3 is an exploded perspective view showing the configuration of the multilayer inductor 11.

  The multilayer inductor 11 is electrically connected to a ceramic body 12 in which a plurality of ceramic layers are laminated, internal conductors 13 a to 13 g formed inside the ceramic body 12, and internal conductors 13 a to 13 g on the surface of the ceramic body 12. The external electrodes 14a and 14b are formed as described above.

  The ceramic body 12 is made of the porcelain composition of the present invention. The inner conductors 13a to 13g are electrically connected in series to form a helical coil. The external electrode 14a is formed on the surface of the ceramic body 12 so as to be connected to one end of the coil formed by the internal conductors 13a to 13g, and the external electrode 14b is connected to the other end of the coil.

  Hereinafter, a method of manufacturing the multilayer inductor 11 will be described with reference to FIG. The same raw material as in Example 1 was prepared as a starting raw material. Thereafter, in the same manner as in Example 1, preparation was performed so that a ceramic composition having a composition ratio shown in Sample 8 of Table 1 was obtained, and the slurry was adjusted to obtain green sheets 12a to 12l.

  The green sheets 12d to 12i were provided with through holes in the thickness direction, and the via holes 15 were formed by filling the through holes with a conductive paste mainly composed of Cu. Furthermore, internal conductors 13a to 13g mainly composed of Cu were formed on the surfaces of the green sheets 12d to 12j by screen printing. The internal conductors 13a to 13g are electrically connected via the via hole 15 to form a spiral coil as a whole.

  Next, green sheets 12a to 12l were laminated and pressed in the thickness direction to obtain a laminated body. A paste containing Cu as a main component was applied to both ends of the laminate, and fired at 980 ° C. in a non-oxidizing atmosphere of nitrogen-hydrogen. Thereby, the ceramic body 12 was obtained. External electrodes 14 a and 14 b were formed on both ends of the ceramic body 12.

  The obtained ceramic body 12 is immersed in a plating solution, and a nickel electrolytic plating film (not shown) as the first plating film and a tin plating film (not shown) as the second plating film on the surfaces of the external electrodes 14a and 14b. The multilayer inductor 11 was obtained.

  In this embodiment, the ceramic body 12 is formed by sheet lamination. However, the ceramic body 12 may be formed by a method such as printing or transfer, and the internal conductors 13a to 13g may be formed by a method such as transfer. Moreover, the filling of the conductive paste into the through holes of the green sheets 12d to 12i and the formation of the internal conductors 13a to 13g may be performed simultaneously. The external electrodes 14a and 14b may be formed by a method such as baking after firing.

  Further, the ceramic electronic component of the present invention is not limited to the multilayer inductor as in the present embodiment, but may be a coil-type electronic component formed by injection molding or the like, or an electronic component such as a capacitor or an LC composite component. There may be.

  According to the multilayer inductor 11 in this example, since the porcelain composition of the present invention is used, deterioration of characteristics and reliability can be suppressed, and the manufacturing yield can be improved. Moreover, since the paste which has Cu as a main component is used for all as the internal conductors 13a-13g and the external electrodes 14a, 14b, the internal conductors 13a-13g and the external electrodes 14a, 14b are burned out by melting or volatilization during firing. Can be prevented. Furthermore, sufficient interface can be given to the interface between the internal conductors 13a to 13g and the external electrodes 14a and 14b.

It is sectional drawing which shows an example of the ceramic multilayer substrate of this invention. It is a perspective view which shows an example of the ceramic electronic component of this invention. It is a disassembled perspective view which shows the structure of the ceramic electronic component of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic layer 2 Via hole 3 Internal conductor 4 External conductor 11 Multilayer inductor 12 Ceramic body 13 Internal conductor 14 External electrode

Claims (4)

A powdered oxide ceramic composition containing Al, Si, Ba, B and Cr as metal elements,
Al is converted to Al ₂ O ₃ in an amount of 11.5 to 14.0% by weight, Si is converted into SiO ₂ in an amount of 54.0 to 70.0% by weight, and Ba is converted into BaO in a range of 4.0 to 30%. .0 wt%, 1.0 to 10.0 wt% in terms of B to B ₂ O _3, and Cr in terms of Cr ₂ O ₃ containing 0.3 to 3.0 wt%,
Furthermore, with respect to 100 parts by weight of these main components, at least one selected from CaO, MgO, ZnO and SrO as a subsidiary component is contained in a total amount of 3 parts by weight or less , and the average particle size is 1.5 μm or less. ,
An oxide porcelain composition characterized by the above.   A ceramic multilayer substrate comprising a ceramic laminate and an internal conductor formed between ceramic layers of the ceramic laminate, wherein the ceramic layer comprises the oxide ceramic composition according to claim 1. A ceramic multilayer substrate.   2. A ceramic electronic component comprising a ceramic body, an inner conductor formed inside the ceramic body, and an external electrode formed on a surface of the ceramic body, wherein the ceramic body is according to claim 1. A ceramic electronic component comprising an oxide porcelain composition.   The ceramic electronic component according to claim 3, wherein the inner conductor and the outer electrode are mainly composed of copper.

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