JP2013135088A - Dielectric glass composition and laminate common mode choke coil including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric glass composition which is included in a laminate common mode choke coil having a structure where a dielectric glass layer is sandwiched with magnetic material portions comprising ferrite or the like, is good in sinterability at a temperature around 900°C, and hardly causes structural defects.SOLUTION: A dielectric glass composition includes 5-40 wt.% of a filler component comprising quartz and 60-95 wt.% of a frit component, and the frit component contains 60.0-89.0 wt.% of Si in terms of oxides, 0.1-3.5 wt.% of Mg in terms of oxides, 10.0-32.0 wt.% of B in terms of oxides, and 0.3-4.0 wt.% of K in terms of oxides. A laminate common mode choke coil includes a dielectric glass layer comprising the dielectric glass composition.

Description

  The present invention relates to a laminated common mode choke coil that can be used in various electronic devices and a dielectric glass composition suitable for the same.

  A common mode choke coil is an electronic component formed by forming two winding conductors on an insulator, and in particular, a laminated type common mode choke coil has two spiral (spiral) via an insulator layer. It has a structure in which conductors face each other. Recently, portable personal computers, especially tablet-type personal computers, have been rapidly spread. In addition, high-speed data reading is performed by adopting an HDD compatible SSD storage device. Along with these changes, the data transfer speed has been further increased and a super speed mode has been added. With such progress, the signal frequency transmitted to the signal line has been increased. Conventionally used common mode choke coils are becoming difficult to take measures against noise while maintaining sufficient signal quality. Against this background, high impedance specifications such as 70-90Ω at 100 MHz with a thickness as small as possible while being as small as 0.6 mm x 0.5 mm are required. It has become like this. Up to now, the number of windings has been increased and miniaturization has been realized, but the reduction in height is still not sufficient.

  In this type of common mode choke coil, a spiral conductor has been embedded in a glass-containing material formed as an insulating layer. And the laminated structure which sandwiches the above-mentioned insulating layer from the upper and lower sides by the magnetic layer comprised with the ferrite is taken. Here, when an insulating layer made of a glass-containing material and a magnetic layer are brought into direct contact with each other, there arises a new problem that the magnetic permeability is lowered or the internal conductor material or the external electrode material is migrated to cause insulation deterioration. The cause of the decrease in magnetic permeability is that the glass component is absorbed while entering the magnetic layer during the shrinkage process during firing during production. Moreover, when a space | gap remains in a glass material, an insulating layer will become easy to absorb moisture. Presence of moisture-absorbed voids causes the above-described migration and insulation deterioration.

  According to Patent Document 1, in order to increase the impedance of the common mode component, at least two magnetic layers above and below the two coiled conductors, and two nonmagnetic layers provided between the two magnetic layers, respectively. Providing a low-permittivity layer containing glass between the non-magnetic layers and forming an insulating layer located between the two conductors with a low-permeability material containing glass doing.

JP 2008-159738 A

  However, the configuration as in Patent Document 1 conflicts with the demand for a low profile. An object of the present invention is to provide a dielectric glass composition having good sinterability in order to realize a reduction in size and height of a laminated common mode choke coil. It is another object of the present invention to provide a laminated common mode choke coil that uses the dielectric glass composition and hardly undergoes insulation deterioration.

As a result of intensive studies by the inventors, the present invention having the following characteristics has been completed.
The dielectric glass composition of the present invention includes 5 to 40 wt% of a filler component made of quartz and 60 to 95 wt% of a frit component. Here, the frit components are Si 0.06 to 89.0 wt% in terms of oxide, Mg 0.1 to 3.5 wt% in terms of oxide, and B 10.0 to 32 in terms of oxide. 0.0 wt% and K in an oxide conversion of 0.3 to 4.0 wt%.
According to another aspect of the present invention, a laminated common mode choke coil is provided. The laminated common mode choke coil includes a dielectric glass layer in which a pair of spiral conductive wires are embedded, and a magnetic material layer above and below the dielectric glass layer, and the dielectric glass layer includes the dielectric material described above. It consists of a glass composition.

  The dielectric glass composition of the present invention is excellent in sinterability at around 900 ° C., and is particularly suitable as a material for a dielectric glass layer for producing a highly reliable laminated common mode choke coil.

It is a typical exploded view of the lamination common mode choke coil of the present invention.

  The present invention will be described in detail with appropriate reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and in the drawings, the characteristic portions of the invention may be emphasized and expressed, so that the accuracy of the scale is not necessarily guaranteed in each part of the drawings. Not.

  The dielectric glass composition of the present invention includes a filler component and a frit component. The frit component is a component that can be softened in a temperature range of about 800 ° C., and the filler component is a component that does not soften in the temperature range. Therefore, when the filler component and the frit component are mixed and heated and then cooled, the filler component forms a glass substrate, and the filler component is discretely present therein. According to the present invention, quartz is used as the filler component, and borosilicate glass having a predetermined composition described later is used as the frit component.

  The dielectric glass composition contains 5 to 40 wt% of a filler component made of quartz and 60 to 95 wt% of a frit component. It is necessary to achieve the object of the present invention to contain the filler component and the frit component in the above ranges. Assuming that the above range is satisfied, the total amount of dielectric glass composition (100 wt%) includes 10 wt% or less zirconia and / or 20 wt% or less alumina as a filler other than quartz. Also good.

The frit component essentially contains Si, Mg, B and K. These elements are typically included in the frit component in the form of an oxide. The content ratios of these elements in the total amount (100 wt%) of the frit component are as follows. Si is 60.0 to 89.0 wt% in terms of oxide (SiO ₂ equivalent), Mg is 0.1 to 3.5 wt% in terms of oxide (MgO equivalent), and B is oxide equivalent (B ₂ O ₃ ) and 10.0 to 32.0 wt%, and K is 0.3 to 4.0 wt% in terms of oxide (K ₂ O). It is necessary to achieve the object of the present invention to contain each of the above elements as the frit component in the above ratio. Assuming that the above range is satisfied, the frit component may contain the following oxides as elements other than the respective elements. The numerical value in parentheses is the upper limit ratio of each oxide that may occupy the total amount of the frit component (100 wt%). SrO (8 wt%), CoO (5 wt%), Li ₂ O ₃ (4 wt%), TiO ₂ (3 wt%), Bi ₂ O ₃ (3 wt%), CuO (5 wt%), BaO (4 wt%), CaO (8 wt%), NaO (2 wt%), Ag ₂ O (3 wt%), etc.

  According to the present invention, the dielectric glass composition may be obtained by mixing the oxide particles constituting the above-mentioned frit component and the quartz particles as the filler component. Preferably, each frit component raw material is mixed, melted, and cooled to obtain a frit material, and then the frit material and quartz particles are mixed to obtain a dielectric glass composition. Good. Hereinafter, typical production methods are described in a non-limiting manner.

As the raw material for the frit component, SiO ₂ powder having an average particle diameter of _{2 to 7} μm, MgO powder having an average particle diameter of 1 to 5 μm, B ₂ O ₃ powder having an average particle diameter of _{3 to 7} μm, and K ₂ having an average particle diameter of _{2 to 6} μm. O is preferably used. Here, the average particle diameter is a value of D50 in the particle size distribution measurement by laser diffraction scattering. Apparatus These are weighed and prepared, put into a platinum crucible or the like, and heated in an electric furnace or the like. Examples of heating conditions include a heating rate of 5 to 20 ° C./h, a maximum temperature of 1300 to 1700 ° C., a holding time at the maximum temperature of 4 to 8 hours, and the like. Under these conditions, the raw material for the frit component melts. Next, the frit material in the form of flake pellets is obtained by cooling the molten frit. The frit material is preferably pulverized to an average particle size of about 0.5 to 2 μm. The frit material thus obtained is mixed with quartz as a filler. The quartz is pulverized before mixing so that the average particle size is preferably about 0.5 to 3 μm. Mixing includes wet mixing for about 15 hours.

  As a suitable use of the dielectric glass composition of the present invention, dielectric materials for various electronic parts can be mentioned. As one form thereof, according to the present invention, a laminated common mode choke coil is provided. FIG. 1 is a schematic exploded view of an example of the laminated common mode choke coil of the present invention. The pair of spiral conductive wires 11 and 12 are embedded in the dielectric glass layers 13 and 14. Magnetic material layers 15 and 16 are laminated on top and bottom of dielectric glass layers 13 and 14 so as to be sandwiched from above and below.

According to the present invention, the above-described dielectric glass composition is used as the material of the dielectric glass layers 13 and 14. A general method is to obtain a slurry by kneading the pulverized dielectric glass composition with a binder in the presence of a solvent. As an example of the composition of the slurry, 100 parts by weight of the pulverized glass dielectric material, 100 to 140 parts by weight of a solvent such as ethanol, preferably 70 to 90 parts by weight of a binder such as polyvinyl acetal resin, dispersion of polystyrene or the like It is preferable to knead 3 to 7 parts by weight of the agent, and preferably 3 to 7 parts by weight of a plasticizer such as a phthalate ester. From this slurry, a green sheet having a thickness of 10 to 20 μm and a width of about 30 cm can be produced by a doctor blade method or the like. ZrO ₂ balls can be used as a mixed medium for slurry preparation. As said binder, polyvinyl butyral resin, methacrylic acid resin, etc. other than polyvinyl acetal resin can be used. As the plasticizer, dioctyl phthalate and the like can be used in addition to dibutyl phthalate. As the solvent, methyl ethyl ketone or the like can be used in addition to toluene. You may add polyethyleneglycol as a dispersing agent as needed.

  Next, a conductor pattern for the conductive wires 11 and 12 is formed on the green sheet. An internal conductor pattern can be formed by printing a paste containing silver powder or the like, which is a material for the internal conductor, on the green sheet. The line width of the conductor pattern is exemplified as 15 to 25 μm, and the distance between lines is exemplified as 8 to 15 μm.

  When forming the conductor pattern, the via holes 11a, 21a, 12a, and 22a and the external terminals 11b, 21b, 12b, and 22b can be appropriately formed, and the conventional technique is appropriately used for the formation method thereof. Can do.

  Further, green sheets for the outer magnetic layers 15, 16, etc. are manufactured from predetermined materials, and they are laminated and fired. Various ferrites can be used as appropriate for the material of the magnetic layer, and specific examples thereof include Ni-Zr-Cu ferrite. In the production of the magnetic material-containing slurry, 200 parts by weight of a magnetic material having an average particle size of preferably 0.3 to 1.5 μm, preferably 250 to 350 parts by weight of a solvent such as ethanol or toluene, polyvinyl acetal resin, etc. The binder is preferably 150 to 250 parts by weight, the dispersant such as polystyrene is preferably 5 to 15 parts by weight, and the plasticizer such as phthalate is preferably 5 to 15 parts by weight. As said binder, polyvinyl butyral resin, methacrylic acid resin, etc. other than polyvinyl acetal resin can be used. As the plasticizer, dioctyl phthalate and the like can be used in addition to dibutyl phthalate. As the solvent, methyl ethyl ketone or the like can be used in addition to toluene. You may add polyethyleneglycol as a dispersing agent as needed.

  Regarding the lamination and firing of each green sheet, the prior art regarding the production of the multilayer electronic component can be referred to as appropriate. For example, as shown in FIG. 1, in order from the bottom, a green sheet for the magnetic layers 15 and 16, a green sheet for the dielectric glass layer 14 on which the external terminals 22b are formed, and a dielectric on which a spiral internal conductor pattern is formed. A green sheet (two sheets) for the body glass layers 13 and 14, a green sheet for the dielectric glass layer 14 on which the external terminals 21b are formed, and a green sheet for the magnetic layers 15 and 16 can be laminated. These are pressure-bonded and degreased in an air atmosphere, and then heated in an air atmosphere, preferably at a heating rate of 5 to 20 ° C./h, for example up to 900 ° C., and held at that temperature for 2 hours Can be fired. After firing, a laminated common mode choke coil is obtained by providing an external terminal.

  In the present invention, in addition to using the above-described dielectric glass composition as a material for the dielectric glass layers 13 and 14, conventional techniques relating to a laminated common mode choke coil or similar electronic components can be used as appropriate.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the embodiments described in these examples. A representative example will be described in an easy-to-understand manner. As a representative example, the sample No. 3 will be described in detail.

Sample No. shown in Table 1 3. Weigh SiO ₂ powder with an average particle diameter of 5 μm, MgO powder with an average particle diameter of ₃ μm, B ₂ O ₃ powder with an average particle diameter of 5 μm, and K ₂ O with an average particle diameter of 4 μm to be a frit raw material. And formulated. The prepared frit powder was put in a platinum crucible, heated at a temperature gradient of 10 ° C./h in an experimental furnace, and melted at 1500 ° C. for 6 hours. The molten frit was then quenched to obtain flake pellets. The flake pellets were pulverized to an average particle size of about 1 μm. The frit thus obtained was wet mixed with quartz as a filler pulverized to an average particle size of about 1 μm for 15 hours. A dielectric glass powder having a composition of 3 was obtained.

(Measurement of sinterability and water absorption rate)
After mixing the frit and filler in the same manner as described above, the mixed powder was spread on a stainless steel pallet and dried at 150 ° C. for 15 hours. About 15 cc of a PVA binder was added to 40 g of this dried mixed powder, and it was molded into a cylindrical shape by a granulation and press molding machine. Thereafter, the binder was removed by heating to 500 ° C. in the atmosphere to obtain a cylindrical molded body having a diameter of 7 mm and a height of 5 mm. This molded body was heated at a temperature gradient of 10 ° C./h and fired at 870 ° C. in the atmosphere for 2 hours. 30 sintered bodies for evaluation of 3 were obtained.

  As for the sinterability of the sintered body, the case where it was sintered at 870 ° C. was marked as “◯”, and the case where it was not sintered was marked as “X”. As for sinterability, a sample having a water absorption rate of 1% or less by the Archimedes method was regarded as having sinterability, and the measurement result of the water supply rate was shown as a numerical value. Those having a water absorption rate exceeding 1% were regarded as having no sinterability, and “not sintered” was described in the remarks. Moreover, what foamed in the glass sintered compact was described as "foaming" in the remarks. During the sintering, the corners of the cylinders were broken and rounded, and those that caused fusion with the firing tool were described as “fused” in the remarks.

(Production of dielectric glass green sheet)
Sample No. 3 parts of glass dielectric powder of composition 3, 120 parts by weight of ethanol as a solvent, 80 parts by weight of polyvinyl acetal resin as a binder, 5 parts by weight of polystyrene as a dispersant, and 5 parts by weight of phthalate as a plasticizer Part was kneaded to obtain a slurry. Using this slurry, a green sheet having a thickness of 15 μm and a width of 30 cm was produced by a doctor blade method. ZrO ₂ balls were used as a mixing medium for slurry preparation. Sample No. 3 was formed into a green sheet having a thickness of 15 μm and a size of 85 mm × 110 mm.

(Formation of internal conductor pattern on glass dielectric layer)
Next, Ag paste is printed on a green sheet cut to 85 mm × 110 mm by a screen printing method or the like to form a spiral conductor pattern having a line width of 30 μm and a line spacing of 25 μm and a conductor pattern connected to an external terminal. did. The spiral conductor pattern and the conductor pattern connected to the external terminal were connected through a hole formed with a green sheet.

(Preparation of magnetic green sheet)
200 parts by weight of Ni—Zr—Cu ferrite powder having an average particle size of 0.5 μm as a magnetic material, 300 parts by weight of ethanol as a solvent, 200 parts by weight of polyvinyl acetal resin as a binder, and polystyrene as a dispersant 10 parts by weight and 10 parts by weight of a phthalate ester as a plasticizer were kneaded to obtain a slurry. Using this slurry, a green sheet having a thickness of 30 μm and a width of 30 cm was obtained by a doctor blade method. ZrO ₂ balls were used as the mixing medium. The prepared green sheets were punched into a size of 85 mm × 110 mm with a molding machine to prepare 12 sheets.

(Production of laminated common mode choke coil)
As shown in FIG. 1, in order from the bottom, a green sheet for magnetic layers 15 and 16, a green sheet for dielectric glass layer 14 on which external terminals 22b are formed, and a dielectric glass on which spiral inner conductor patterns are formed. A green sheet (two sheets) for the layers 13 and 14, a green sheet for the dielectric glass layer 14 on which the external terminals 21b were formed, and a green sheet for the magnetic layers 15 and 16 were laminated. After these are pressure-bonded and degreased in an air atmosphere, firing is preferably performed in an air atmosphere at a rate of temperature increase of 10 ° C./h to 900 ° C. and held at that temperature for 2 hours. went. After firing, a laminated common mode choke coil was obtained by providing external terminals.

(Reliability test of laminated common mode choke coil)
In the reliability test, the number of samples having a resistance value of less than 100 MΩ over 1000 hours under the conditions of a chip of 85 ° C. and a humidity of 85% was defined as the number of deterioration.

  Sample No. For the samples other than 3, each sample was prepared in the same manner as described above except that the composition of the dielectric glass composition was as shown in Table 1 below, and the results shown in Table 1 were obtained using the same test method. Obtained.

(Observation of bonding interface between magnetic layer and dielectric glass layer)
The gap at the joint interface of the obtained laminated common mode choke coil was judged by SEM observation after polishing the cross section of each coil produced.

  Table 1 summarizes the composition and evaluation results of the dielectric glass composition. “%” In the table means “wt%”. Samples marked with an asterisk correspond to comparative examples.

(Summary of implementation results)
As described in Table 1, it was found that the preferred weight ratio range of the filler is 5 to 40 wt%. That is, since it is 4 wt% or less, it cannot be put to practical use because it is fused. Moreover, since it will not sinter if it is 44 wt% or more, it cannot be used. From this result, the object of the present invention can be achieved if it is in the range of at least 5 to 40 wt%. Next, a discussion of the results for each component constituting the frit is as follows. First, sample no. From the result of 8-14, sample No. whose content of Si component is 65.0-89.0 mass parts in conversion of an oxide. Nos. 10 to 12 were sintered at 870 ° C. and had excellent sinterability and no voids. On the other hand, Sample No. whose Si component content is less than 65.0 parts by mass. 13 and 14 were fused. In addition, Sample No. in which the content of Si component exceeds 89.0 parts by mass. 8 and 9 were not sintered. Sample No. From the results of Nos. 15 to 21, the sample No. Nos. 17 to 19 were sintered at 870 ° C. and had excellent sinterability and no voids. On the other hand, Sample No. whose Mg component content is less than 0.1 parts by mass. In 15 and 16, voids were generated. In addition, Sample No. in which the content of the Mg component exceeds 3.0 parts by mass. In Nos. 20 and 21, many bubbles remained in the glass sintered body. Sample No. From the result of 22-28, sample No. whose content of B component is 10.0-32.0 mass parts in conversion of an oxide. Nos. 24-26 were sintered at 870 ° C. and had excellent sinterability and no voids. On the other hand, Sample No. whose B component content is less than 10.0 parts by mass. 22 and 23 were not sintered. In addition, Sample No. in which the content of the B component exceeds 32.0 parts by mass. 27 and 28 were fused. Sample No. From the results of 29-35, the sample No. whose content of K component is 0.3-4.0 parts by mass in terms of oxide Nos. 31 to 33 were sintered at 870 ° C. and had excellent sinterability and no voids. On the other hand, Sample No. whose K component content is less than 0.3 parts by mass. 29 and 30 were not sintered. In addition, the sample No. in which the content of the K component exceeds 4.0 parts by mass. 34 and 35 were fused.

11, 12 Conductor; 13, 14 Dielectric glass layer; 15, 16 Magnetic layer

Claims (2)

  It contains 5 to 40 wt% of a filler component made of quartz and 60 to 95 wt% of a frit component, and the frit component is 60.0 to 89.0 wt% in terms of oxide of Si and 0.1 in terms of oxide of Mg. A dielectric glass composition containing: -3.5 wt%, B: 10.0-32.0 wt% in terms of oxide, and K: 0.3-4.0 wt% in terms of oxide.   A dielectric glass layer in which a pair of spiral conductive wires are embedded, and a magnetic material layer above and below the dielectric glass layer, the dielectric glass layer comprising the dielectric glass composition according to claim 1. A laminated common mode choke coil.

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