WO2013099297A1 - Laminate inductor - Google Patents
Laminate inductor Download PDFInfo
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- WO2013099297A1 WO2013099297A1 PCT/JP2012/050207 JP2012050207W WO2013099297A1 WO 2013099297 A1 WO2013099297 A1 WO 2013099297A1 JP 2012050207 W JP2012050207 W JP 2012050207W WO 2013099297 A1 WO2013099297 A1 WO 2013099297A1
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- soft magnetic
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- magnetic alloy
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- magnetic layer
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
- H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
- H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/0027—Thick magnetic films
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/33—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials mixtures of metallic and non-metallic particles; metallic particles having oxide skin
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
- H01F17/0013—Printed inductances with stacked layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
- H01F17/0013—Printed inductances with stacked layers
- H01F2017/002—Details of via holes for interconnecting the layers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
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- H01F17/0006—Printed inductances
- H01F2017/0066—Printed inductances with a magnetic layer
Definitions
- the present invention relates to a multilayer inductor.
- Patent Document 1 discloses a composite magnetic material in which a mixture of an alloy powder mainly composed of iron (Fe), aluminum (Al), and silicon (Si) and a binder is compression-molded and then heat-treated in an oxidizing atmosphere. A manufacturing method is disclosed.
- Patent Document 2 a plurality of strip conductors are provided in parallel to the laminated surface of the ceramic laminate, and a connection conductor composed of a plurality of via holes connecting the ends of two or more strip conductors sandwiching the ceramic laminate,
- a laminated coil component is disclosed in which a coil conductor is configured in a ceramic laminate.
- Patent Document 3 is obtained by laminating a metal magnetic layer formed using a metal magnetic paste containing metal magnetic particles and a thermosetting resin, and a conductor pattern formed using a conductor paste.
- a method of manufacturing a laminated electronic component in which a coil is formed in a laminated body is disclosed.
- a multilayer inductor having a magnetic layer made of a soft magnetic alloy instead of ferrite can meet the demand for a large current as described above, but on the other hand, the conduction failure rate in the obtained multilayer inductor tends to be high.
- An object of the present invention is to provide a multilayer inductor that uses a soft magnetic alloy as a magnetic material, increases the magnetic permeability, exhibits a high L value, and can cope with the miniaturization of devices.
- a multilayer inductor having a plurality of magnetic layers made of soft magnetic alloy particles, a plurality of coil segments made of Ag-containing material, and a relay segment made of Ag-containing material.
- at least a part of the periphery of the soft magnetic alloy particles has an oxide film formed by oxidizing the soft magnetic alloy.
- the magnetic layer and the coil segment constitute a laminated structure in which the coil segments are alternately stacked, the relay segment is formed so as to pass through the magnetic layer, and the coil segment and the relay segment are electrically connected. Constructs an integrated internal conductor.
- the soft magnetic alloy particles are Fe-Si-M based soft magnetic alloys (where M is a metal element that is easier to oxidize than Fe), and an oxidation formed around adjacent soft magnetic alloy particles. There are joints through the coating and joints between the soft magnetic alloy particles in the metal part where there is no oxide coating.
- the Ag particles are present in the magnetic layer in the vicinity of the inner conductor and / or the soft magnetic layer has a convex portion made of Ag extending from the inner conductor. Even when it is subjected to a cycle, a difference in thermal expansion hardly occurs between the inner conductor and the magnetic layer, and the adhesion between the inner conductor and the magnetic layer is improved. As a result, poor conduction is reduced.
- the oxide film around the soft magnetic alloy particles has large irregularities, Ag migration is suppressed, and reliability is unlikely to deteriorate even when a moisture resistance load is applied.
- FIG. 1A is a schematic cross-sectional view of a multilayer inductor.
- FIG.1 (b) is the elements on larger scale of Fig.1 (a).
- the multilayer inductor 1 that is the subject of the present invention has a structure in which most of the inner conductor 20 is buried in a magnetic part (laminate of the magnetic layer 10).
- the inner conductor 20 is a coil formed in a spiral shape, and other examples include a spiral coil, a meander (meandering) conductor, a linear conductor, and the like.
- the inner conductor 20 has a coil segment 21 and a relay segment 22.
- the coil segment 21 and the magnetic layer 10 constitute a laminated structure in which they are alternately laminated.
- the relay segment 22 is formed so as to penetrate the magnetic layer 10.
- the relay segment 22 is formed so as to conduct the plurality of coil segments 21.
- FIG. 2 is a schematic exploded view of a typical multilayer inductor.
- the internal conductor 20 has a coil structure in which coil segments CS1 to CS5 and relay segments IS1 to IS4 connecting the coil segments CS1 to CS5 are spirally integrated.
- the coil segments CS1 to CS4 have a U shape
- the coil segment CS5 has a strip shape
- each relay segment IS1 to IS4 has a column shape penetrating the magnetic layers ML1 to ML4.
- the coil segment 21 and the relay segment 22 are made of an Ag-containing material.
- the Ag-containing material is typically Ag substantially free of other metals, and may be a mixture or alloy of 100 parts by weight of Ag and 50 parts by weight or less of other metals.
- the metal include, but are not limited to, Au, Cu, Pt, and Pd.
- FIG. 1B is a schematic enlarged view of two coil segments 21 and a magnetic layer 10 sandwiched between them. Unlike FIG. 1A, in FIG. 1B, the hatching notation indicating the magnetic layer 10 is omitted.
- both the Ag particles 30 and the convex portions 31 are present.
- the Ag particles 30 are preferably made of Ag present discontinuously between the soft magnetic alloy particles in the magnetic layer 10 around the inner conductor 20.
- the convex portion 31 is preferably made of Ag that continuously exists between the inner conductor 20 and the soft magnetic alloy particles in the magnetic layer 10 around the inner conductor 20.
- the coil segment 21 is depicted as a part of the inner conductor 20 in FIG. 1B, Ag particles and / or convex portions made of Ag extending from the relay segment also exist in the vicinity of the relay segment. It is preferable to do.
- the Ag particles 30 and the convex portions 31 are derived from, for example, an Ag-containing material constituting the internal electrode 20. Typically, Ag “diffuses” from the Ag-containing material constituting the inner conductor 20, and the Ag particles 30 and the convex portions 31 exist.
- the magnetic layer 10 is formed by accumulating a large number of soft magnetic alloy particles. In addition, voids are formed between the soft magnetic alloy particles. There are also air gaps in the magnetic layer 10 around the inner conductor 20. A part of Ag constituting the inner conductor 20 enters a gap in the peripheral magnetic layer 10. Such a state is referred to herein as “diffusion”.
- the presence of the Ag particles 30 and / or the convex portions 31 in the magnetic layer 10 means that, for example, a cross section of the multilayer inductor 1 is photographed using a scanning electron microscope (SEM), and then energy is consumed. This can be confirmed by obtaining the chemical composition by the ZAF method by dispersive X-ray analysis (EDS).
- the size (equivalent sphere diameter) of the Ag particles 30 is not particularly limited, and is preferably 1 to 10 ⁇ m. It is preferable that the Ag particles 30 occupy voids between the soft magnetic alloy particles constituting the magnetic layer 10.
- the Ag particles 30 may be present in an oxide film (not shown) around the individual soft magnetic alloy particles.
- the Ag-free layered region 11 exists in the magnetic layer 10 sandwiched between the coil segments 21.
- the layered region 11 includes Ag that is a part of the inner conductor 20 itself, and Ag particles 30 that are separated from the inner conductor 20 and are in the magnetic layer 10.
- the above-mentioned convex part 31 also means a layered region where none exists.
- the existence of such a layered region 11 means that the diffusion of Ag does not extend over the entire area of the magnetic layer 10, and therefore, an undesirable initial interlayer short circuit is less likely to occur.
- the boundary of the layer region 11 in the absence of Ag is determined to be substantially parallel to the coil segment 21.
- the layer thickness of the layer region 11 in the absence of Ag is preferably 3 ⁇ m or more, more preferably 5 to 25 ⁇ m.
- a large number of soft magnetic alloy particles are accumulated to constitute a magnetic part having a predetermined shape.
- the magnetic body portion can be evaluated as an assembly of the magnetic layer 10 divided by the coil segment 21, and at the same time, it is evaluated that the magnetic layer 10 and the coil segment 21 constitute a laminated structure.
- Each of the soft magnetic alloy particles has an oxide film formed on at least a part of the periphery thereof, preferably substantially the whole, and this oxide film ensures the insulation of the magnetic part.
- Adjacent soft magnetic alloy particles are generally bonded via an oxide film of each soft magnetic alloy particle to constitute a magnetic part having a certain shape.
- the oxide film is preferably a film formed by oxidizing the refractory alloy particles themselves.
- metal portions of adjacent soft magnetic alloy particles may be bonded to each other. Further, in the vicinity of the inner conductor 20, the soft magnetic alloy particles and the inner conductor 20 are in close contact mainly through the oxide film.
- the soft magnetic alloy particles are preferably made of an Fe-M-Si alloy (where M is a metal that is easier to oxidize than iron).
- the oxide film is preferably formed by oxidation of the soft magnetic alloy. It is confirmed that it contains at least Fe 3 O 4 that is a magnetic material, Fe 2 O 3 that is a non-magnetic material, and MO x (x is a value determined according to the oxidation number of the metal M). Yes.
- the presence of the bond through the oxide film described above is clear, for example, by visually confirming that the oxide film of the adjacent soft magnetic alloy particles is in the same phase in an SEM observation image magnified about 3000 times. Can be judged.
- the presence of the bond through the oxide film improves the mechanical strength and insulation of the multilayer inductor 1.
- the oxide film usually has relatively large irregularities, the migration of Ag is suppressed and the moisture resistance is improved.
- the multilayer inductor 1 is preferably bonded through the oxide film of the adjacent soft magnetic alloy particles. However, if even a part of the multilayer inductor 1 is bonded, the corresponding mechanical strength and insulation can be improved. Such a form is also an embodiment of the present invention.
- the adjacent soft magnetic alloy particles maintain the same phase in, for example, an SEM observation image magnified about 3000 times.
- the presence of a bond between metal parts can be clearly determined by visually confirming that a bond point is present.
- the magnetic permeability can be further improved by the presence of the coupling between the soft magnetic alloy particles.
- the “joint part between metal parts where no oxide film is present” means a part in which adjacent alloy particles are in direct contact with each other, for example, in a strict sense. It is a concept including a metal bond, a mode in which metal parts are in direct contact with each other, and an exchange of atoms is not seen, and an intermediate mode between them.
- the metal bond in the strict sense means that the requirement such as “the atoms are regularly arranged” is satisfied.
- both ends of the inner conductor 20 are typically drawn to opposite end surfaces of the outer surface of the multilayer inductor 1 through lead conductors (not shown), respectively, and external terminals (not shown). Connected to. Conventional technology can be used as appropriate for the structure and connection mode of the external terminals.
- a typical and non-limiting manufacturing method of the multilayer inductor 1 according to the present invention will be described.
- a magnetic paste (slurry) prepared in advance is applied to the surface of a base film made of resin or the like using a coating machine such as a doctor blade or a die coater. This is dried with a dryer such as a hot air dryer to obtain a green sheet.
- the magnetic paste includes soft magnetic alloy particles, typically a polymer resin as a binder, and a solvent.
- Soft magnetic alloy particles are particles exhibiting soft magnetism mainly composed of an alloy.
- the alloy include Fe-M-Si alloys (where M is a metal that is easier to oxidize than iron).
- M include Cr and Al, and Cr is preferable.
- the soft magnetic alloy particles include particles produced by an atomizing method.
- the chromium content in the Fe—Cr—Si alloy is preferably 2 to 8 wt%.
- the presence of chromium is preferable in that it forms a passive state during heat treatment to suppress excessive oxidation and develop strength and insulation resistance.
- the Si content in the Fe—Cr—Si soft magnetic alloy is preferably 1.5 to 7 wt%.
- a high Si content is preferable in terms of high resistance and high magnetic permeability, and a low Si content provides good moldability, and the above preferable range is proposed in consideration of these.
- the remainder other than Si and Cr is preferably iron except for inevitable impurities.
- metals that may be contained in addition to Fe, Si, and Cr include aluminum, magnesium, calcium, titanium, manganese, cobalt, nickel, and copper, and examples of nonmetals include phosphorus, sulfur, and carbon. .
- a cross section of the multilayer inductor 1 is photographed using a scanning electron microscope (SEM), and then energy dispersive X-ray analysis (EDS).
- SEM scanning electron microscope
- EDS energy dispersive X-ray analysis
- the particle diameter of the soft magnetic alloy particles used as a raw material for the magnetic body portion 10 can be appropriately selected.
- d50 is preferably 2 to 20 ⁇ m, more preferably 3 to 10 ⁇ m on a volume basis. It is.
- the d50 of the soft magnetic alloy particles is measured using a particle size / particle size distribution measuring device (for example, Microtrack manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method.
- a particle size / particle size distribution measuring device for example, Microtrack manufactured by Nikkiso Co., Ltd.
- the particle size of the soft magnetic alloy particles as the raw material particles is approximately equal to the particle size of the soft magnetic alloy particles constituting the magnetic part of the multilayer inductor 10. .
- the above-mentioned magnetic paste preferably contains a polymer resin as a binder.
- the type of the polymer resin is not particularly limited, and examples thereof include polyvinyl acetal resins such as polyvinyl butyral (PVB).
- the type of solvent for the magnetic paste is not particularly limited, and for example, glycol ethers such as butyl carbitol can be used.
- the blending ratio of soft magnetic alloy particles, polymer resin, solvent and the like in the magnetic paste can be adjusted as appropriate, and the viscosity of the magnetic paste can be set accordingly.
- the green sheet is punched to form through holes (through holes) in a predetermined arrangement.
- the arrangement of the through holes is set so that when the sheets are laminated, the internal conductor 20 is formed by the through hole (that is, the relay segment 22) filled with the conductor and the coil segment 21.
- the arrangement of the through holes for forming the inner conductor and the shape of the conductor pattern for forming the coil segment conventional techniques can be used as appropriate, and specific examples are described with reference to the drawings in the following embodiments. Explained.
- Conductor paste is preferably used for filling the through holes and for printing the conductor pattern.
- the conductor paste contains an Ag-containing material, typically a polymer resin as a binder, and a solvent.
- the particle diameter of the Ag-containing material as the conductor particles can be appropriately selected, and d50 is preferably 1 to 10 ⁇ m on a volume basis.
- the d50 of the conductor particles is measured using a particle size / particle size distribution measuring apparatus (for example, Microtrack manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method.
- the conductor paste preferably contains a polymer resin as a binder.
- the type of the polymer resin is not particularly limited, and examples thereof include polyvinyl acetal resins such as polyvinyl butyral (PVB).
- the kind of the solvent of the conductor paste is not particularly limited, and for example, glycol ether such as butyl carbitol can be used.
- the mixing ratio of Ag-containing material, polymer resin, solvent, etc. in the conductive paste can be adjusted as appropriate, and the viscosity of the conductive paste can be set accordingly.
- the conductor paste is printed on the surface of the green sheet, and this is dried with a dryer such as a hot air dryer to form a conductor pattern corresponding to the coil segment. Form.
- a part of the conductor paste is also filled in the above-described through hole.
- the conductor paste filled in the through hole and the printed conductor pattern constitute the shape of the internal conductor 20.
- the green sheets after printing are stacked in a predetermined order using an adsorption conveyance machine and a press machine, and thermocompression bonded to produce a laminate. Subsequently, using a cutting machine such as a dicing machine or a laser processing machine, the multilayer body is cut into a component body size, and a pre-heat treatment chip including a magnetic body portion and an internal conductor before the heat treatment is manufactured.
- a cutting machine such as a dicing machine or a laser processing machine
- the chips before the heat treatment are heat-treated in an oxidizing atmosphere such as the air using a heating device such as a firing furnace.
- the heat treatment atmosphere is not particularly limited as long as it is an oxidizing atmosphere, and air or dry air is desirable in consideration of production.
- the temperature is preferably increased from 300 to 600 ° C. for 1 to Hold for 600 minutes, then raise the temperature further.
- the maximum temperature is preferably 600 ° C. or higher, more preferably 700 to 900 ° C., and the maximum temperature is preferably maintained for 0.5 to 3 hours.
- the fine gaps are usually filled with a mixture of a solvent and a binder. These mixtures disappear during the heating process, and the fine gaps turn into pores.
- the soft magnetic alloy particles are densely formed to form a magnetic part, and typically, an oxide film is formed on the surface of each soft magnetic alloy particle.
- the Ag-containing material is sintered to form the internal conductor 20. Thereby, the multilayer inductor 1 is obtained.
- external terminals are formed after heat treatment.
- a coating machine such as a dip coating machine or a roller coating machine
- a conductor paste prepared in advance is applied to both ends in the length direction of the multilayer inductor 1, and this is applied using a heating device such as a firing furnace, for example, about 600.
- An external terminal is formed by performing a baking process at a temperature of about 1 hr.
- the conductor paste for the external terminals the above-described paste for printing a conductor pattern or a paste similar thereto can be used as appropriate.
- the multilayer inductor 1 as a part has a length of about 3.2 mm, a width of about 1.6 mm, a height of about 1.0 mm, and the whole has a rectangular parallelepiped shape.
- FIG. 2 is a schematic exploded view of a multilayer inductor.
- the magnetic part in the region where the inner conductor is formed has a structure in which a total of five magnetic layers ML1 to ML5 are integrated.
- An upper cover region and a lower cover region exist so as to sandwich the region where the inner conductor is formed, and the upper cover region has a structure in which eight magnetic layers ML6 are integrated.
- the lower cover region has a structure in which seven magnetic layers ML6 are integrated.
- the length of the multilayer inductor 1 is about 3.2 mm, the width is about 1.6 mm, and the height is about 1.0 mm.
- Each of the magnetic layers ML1 to ML6 has a length of about 3.2 mm, a width of about 1.6 mm, and a thickness of about 30 ⁇ m.
- Each of the magnetic layers ML1 to ML6 is formed mainly of soft magnetic alloy particles having the composition and average particle diameter (d50) shown in Table 1 which are soft magnetic alloy particles, and does not contain a glass component.
- an oxide film exists on the surface of each soft magnetic alloy particle, and the soft magnetic alloy particles in the magnetic body part and the upper and lower cover regions pass through the oxide film of each adjacent alloy particle. The present inventors confirmed that they were mutually bonded by SEM observation (3000 times).
- the inner conductor 20 has a coil structure in which a total of five coil segments CS1 to CS5 and a total of four relay segments IS1 to IS4 connecting the coil segments CS1 to CS5 are spirally integrated.
- the inner conductor 20 is obtained by heat-treating silver particles, and the volume-based d50 of the silver particles used as a raw material is 5 ⁇ m. Only Comparative Example 4 used copper particles instead of silver particles.
- the four coil segments CS1 to CS4 have a U shape, and the one coil segment CS5 has a strip shape.
- Each coil segment CS1 to CS5 has a thickness of about 20 ⁇ m and a width of about 0.2 mm. It is.
- the uppermost coil segment CS1 has a continuous L-shaped lead portion LS1 used for connection with an external terminal, and the lowermost coil segment CS5 is L-shaped used for connection with an external terminal.
- the lead-out portion LS2 is continuously formed.
- Each of the relay segments IS1 to IS4 has a column shape penetrating the magnetic layers ML1 to ML4, and each has a diameter of about 15 ⁇ m.
- Each external terminal extends to each end face in the length direction of the multilayer inductor 1 and four side faces in the vicinity of the end face, and has a thickness of about 20 ⁇ m.
- One external terminal is connected to the edge of the lead portion LS1 of the uppermost coil segment CS1, and the other external terminal is connected to the edge of the lead portion LS2 of the lowermost coil segment CS5.
- These external terminals were obtained mainly by heat-treating silver particles having a volume-based d50 of 5 ⁇ m.
- a magnetic paste consisting of 85 wt% of soft magnetic alloy particles shown in Table 1, 13 wt% of butyl carbitol (solvent), and 2 wt% of polyvinyl butyral (binder) was prepared. Using a doctor blade, this magnetic paste was applied to the surface of a plastic base film, and this was dried with a hot air dryer at about 80 ° C. for about 5 minutes. In this way, a green sheet was obtained on the base film. Thereafter, the green sheet was cut to obtain first to sixth sheets corresponding to the magnetic layers ML1 to ML6 (see FIG. 2) and having a size suitable for multi-cavity.
- the first sheet corresponding to the magnetic layer ML1 was punched to form through holes corresponding to the relay segment IS1 in a predetermined arrangement.
- through holes corresponding to the relay segments IS2 to IS4 were formed in a predetermined arrangement in the second to fourth sheets corresponding to the magnetic layers ML2 to ML4, respectively.
- a conductor paste consisting of 85 wt% of the Ag particles, 13 wt% of butyl carbitol (solvent), and 2 wt% of polyvinyl butyral (binder) is printed on the surface of the first sheet. Then, this was dried with a hot air dryer under conditions of about 80 ° C. and about 5 minutes, and a first printed layer corresponding to the coil segment CS1 was produced in a predetermined arrangement. Similarly, second to fifth printed layers corresponding to the coil segments CS2 to CS5 were formed in a predetermined arrangement on the surfaces of the second to fifth sheets.
- each of the first to fourth sheets Since the through-holes formed in each of the first to fourth sheets are located at the positions overlapping the end portions of the first to fourth printed layers, a part of the conductor paste is formed when the first to fourth printed layers are printed. Filling each through hole, first to fourth filling portions corresponding to the relay segments IS1 to IS4 are formed.
- the first to fourth sheets provided with the printing layer and the filling unit, the fifth sheet provided only with the printing layer, and the printing layer and the filling unit are provided using an adsorption conveyance machine and a press.
- This laminated body was cut into a component body size with a cutting machine to obtain a chip before heat treatment.
- a number of pre-heat-treated chips were heat-treated in a lump in an air atmosphere using a firing furnace.
- heating is performed under conditions of about 300 ° C. and about 1 hr, and then heat treatment is performed according to the conditions described later, so that the soft magnetic alloy particles are densely formed to form the magnetic body portion 10.
- the particles were sintered to form the inner conductor 20, thereby obtaining a component main body.
- the heat treatment conditions in each example and comparative example are as follows. Common items: The maximum temperature was 700 ° C., and this temperature was maintained for 1 hour. In Example 1, the temperature was maintained at 600 ° C. for 1 hour during the temperature rising process. In Example 2, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process. In Example 3, the temperature was maintained at 600 ° C. for 10 hours during the temperature raising process. In Example 4, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process. In Comparative Example 1, the temperature was maintained at 600 ° C. for 20 hours during the temperature raising process. In Comparative Example 2, holding at a specific temperature during the temperature rising process was not performed. In Comparative Example 3, holding at a specific temperature during the temperature rising process was not performed. In Comparative Example 4, the temperature was kept at 600 ° C. for 1 hour during the temperature raising process.
- a conductive paste containing 85 wt% of the above silver particles, 13 wt% of butyl carbitol (solvent) and 2 wt% of polyvinyl butyral (binder) is applied to both ends in the longitudinal direction of the component body, and this is fired Baking treatment was performed in a furnace under conditions of about 600 ° C. and about 1 hr. As a result, the solvent and the binder disappeared, the silver particles were sintered, the external terminals were formed, and the multilayer inductor 1 was obtained.
- the thickness of the layer region 11 in the absence of Ag was measured. The measurement was performed using the SEM image of the cross section, and for one example / comparative example, 100 measurement data were obtained by measuring the thickness of 5 layers for each of the 20 laminated inductors. The minimum value is listed. The distance between the two coil segments was 17.8 ⁇ m.
- the reliability of the obtained multilayer inductor was evaluated.
- Reliability evaluation was an initial Q value and a Q value after a moisture resistance load test, and was measured at a frequency of 1 MHz using an impedance analyzer 4294A manufactured by Agilent.
- the evaluation indexes in the initial value evaluation are as follows. ⁇ ⁇ ⁇ ⁇ Q value is 40 or more. X ... Q value is less than 40. -...
- the Q value as an inductor was not obtained.
- the continuity after the heat cycle in the obtained multilayer inductor was evaluated.
- the heat cycle conditions were 55 ° C. to 125 ° C. and a holding time of 30 minutes (100 cycles).
- the case where continuity was recognized was evaluated as ⁇
- the case where continuity was not achieved was evaluated as x
- the case where an initial Q value was not obtained and was not evaluated was evaluated as-.
- the Q value after the moisture resistance load test in the obtained multilayer inductor was measured.
- the conditions of the moisture resistance load test were 60 ° C., 95% RH, 1.2 A, and 1000 hr.
- the measurement condition of the Q value is the same as the initial Q value measurement.
- the evaluation indexes based on the evaluation are as follows. ⁇ : The rate of change of Q value from the humidity resistance load test (initial value) is less than 30% in absolute value.
- X The rate of change of the Q value from before the moisture resistance load test (initial value) is 30% or more in absolute value. -... The initial Q value was not obtained and was not evaluated.
- Fe—Cr—Si is 4.5 wt% Cr, 3.5 wt% Si, the balance is Fe, and Fe—Si—Al is 5.5 wt% Al. , Si is 9.5 wt%, the balance is Fe, Ni—Zn ferrite is 11 mol% NiO, 20 mol% ZnO, 10 mol% CuO, and 49 mol% Fe 2 O 3 .
- each example was excellent in reliability and conductivity after heat cycle.
- Comparative Example 1 Ag diffused almost throughout the magnetic layer, and the initial Q value was low, so that it was not worth performing the subsequent evaluation.
- Comparative Example 2 Ag migrated, the Q value after moisture resistance load decreased, and the reliability was low.
- Comparative Example 3 the Ag particles are not present in the magnetic layer, and during the heat cycle, peeling that seems to be due to the difference in thermal expansion between the internal electric wire and the magnetic layer occurs, leading to disconnection of the peeled fragile portion, and conduction. Sex deteriorated.
- Comparative Example 4 since copper was oxidized and the initial Q value was low, it was not worth performing the subsequent evaluation.
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Abstract
The purpose of the present invention is to provide a laminate inductor which uses a soft magnetic alloy as the magnetic material, has a high magnetic permeability, and which is highly reliable and has reduced conduction failures. This laminate inductor (1) comprises multiple magnetic layers (10) formed from soft magnetic alloy particles, and multiple coils and junction segments (21, 22) comprising an Ag-containing material, and in at least a part of the periphery of the soft magnetic alloy particles is an oxide film formed by oxidization of the soft magnetic alloy. The coil segments (21) and the junction segments (22) configure an electrically integrated internal conducting body (20). There are Ag particles (30) present in a magnetic layer (10) on the periphery of the internal conductive body (20), and/or, there are protrusions (31) comprising Ag and extending from the internal conductive body (20) in a soft magnetic layer (19). Between the magnetic layers (10) sandwiched by the coil segments (21), there is a layer region (11) with no Ag.
Description
本願は2011年12月28日に日本で出願された特願2011-289132に基づく優先権を主張しており、参照することによりその内容は本明細書に包含される。
本発明は積層インダクタに関する。 This application claims priority based on Japanese Patent Application No. 2011-289132 filed in Japan on Dec. 28, 2011, the contents of which are incorporated herein by reference.
The present invention relates to a multilayer inductor.
本発明は積層インダクタに関する。 This application claims priority based on Japanese Patent Application No. 2011-289132 filed in Japan on Dec. 28, 2011, the contents of which are incorporated herein by reference.
The present invention relates to a multilayer inductor.
従来より、積層インダクタの製造方法の一つとして、フェライト等を含有するセラミックグリーンシートに内部導体パターンを印刷し、これらのシートを積層し、焼成する方法が知られている。
Conventionally, as one method of manufacturing a multilayer inductor, a method of printing an internal conductor pattern on a ceramic green sheet containing ferrite or the like, laminating these sheets, and firing is known.
特許文献1には、鉄(Fe)、アルミニウム(Al)、珪素(Si)を主成分とする合金粉末と結着剤からなる混合物を圧縮成形後、酸化性雰囲気中で熱処理する複合磁性材料の製造方法が開示されている。
特許文献2には、セラミック積層体の積層面に平行に複数の帯状導体が設けられ、セラミック積層体を挟んだ2以上の帯状導体の端部を接続する複数のバイアホールからなる接続導体によって、コイル導体がセラミック積層体内に構成されてなる、積層コイル部品が開示されている。
特許文献3には、金属磁性体粒子と熱硬化性樹脂を含有する金属磁性体ペーストを用いて形成された金属磁性体層と、導体ペーストを用いて形成された導体パターンとを積層し、得られる積層体内にコイルが形成されてなる積層型電子部品の製造方法が開示されている。Patent Document 1 discloses a composite magnetic material in which a mixture of an alloy powder mainly composed of iron (Fe), aluminum (Al), and silicon (Si) and a binder is compression-molded and then heat-treated in an oxidizing atmosphere. A manufacturing method is disclosed.
In Patent Document 2, a plurality of strip conductors are provided in parallel to the laminated surface of the ceramic laminate, and a connection conductor composed of a plurality of via holes connecting the ends of two or more strip conductors sandwiching the ceramic laminate, A laminated coil component is disclosed in which a coil conductor is configured in a ceramic laminate.
Patent Document 3 is obtained by laminating a metal magnetic layer formed using a metal magnetic paste containing metal magnetic particles and a thermosetting resin, and a conductor pattern formed using a conductor paste. A method of manufacturing a laminated electronic component in which a coil is formed in a laminated body is disclosed.
特許文献2には、セラミック積層体の積層面に平行に複数の帯状導体が設けられ、セラミック積層体を挟んだ2以上の帯状導体の端部を接続する複数のバイアホールからなる接続導体によって、コイル導体がセラミック積層体内に構成されてなる、積層コイル部品が開示されている。
特許文献3には、金属磁性体粒子と熱硬化性樹脂を含有する金属磁性体ペーストを用いて形成された金属磁性体層と、導体ペーストを用いて形成された導体パターンとを積層し、得られる積層体内にコイルが形成されてなる積層型電子部品の製造方法が開示されている。
In Patent Document 2, a plurality of strip conductors are provided in parallel to the laminated surface of the ceramic laminate, and a connection conductor composed of a plurality of via holes connecting the ends of two or more strip conductors sandwiching the ceramic laminate, A laminated coil component is disclosed in which a coil conductor is configured in a ceramic laminate.
Patent Document 3 is obtained by laminating a metal magnetic layer formed using a metal magnetic paste containing metal magnetic particles and a thermosetting resin, and a conductor pattern formed using a conductor paste. A method of manufacturing a laminated electronic component in which a coil is formed in a laminated body is disclosed.
近年、積層インダクタには大電流化(定格電流の高値化を意味する)が求められており、該要求を満足するために、磁性体の材質を従前のフェライトから軟磁性合金に切り替えることが検討されている。軟磁性合金として提案されるFe-Cr-Si合金やFe-Al-Si合金は、材料自体の飽和磁束密度がフェライトに比べて高い。
In recent years, there has been a demand for higher current (meaning higher rated current) in multilayer inductors, and in order to satisfy this requirement, switching the magnetic material from conventional ferrite to a soft magnetic alloy has been studied. Has been. Fe—Cr—Si alloys and Fe—Al—Si alloys proposed as soft magnetic alloys have a higher saturation magnetic flux density than the ferrite itself.
フェライトに代えて軟磁性合金からなる磁性体層を有する積層インダクタは上述のとおり大電流化の要求に応え得るが、その反面、得られる積層インダクタにおける導通不良率が高くなる傾向にある。本発明は軟磁性合金を磁性材料として用い、透磁率を高めて、高いL値を呈し、デバイスの小型化にも対応できる積層インダクタを提供することを課題とする。
A multilayer inductor having a magnetic layer made of a soft magnetic alloy instead of ferrite can meet the demand for a large current as described above, but on the other hand, the conduction failure rate in the obtained multilayer inductor tends to be high. An object of the present invention is to provide a multilayer inductor that uses a soft magnetic alloy as a magnetic material, increases the magnetic permeability, exhibits a high L value, and can cope with the miniaturization of devices.
本発明者らが鋭意検討した結果、以下の特徴を有する積層インダクタの発明を完成した。本発明によれば、軟磁性合金粒子で形成された複数の磁性体層と、Ag含有材料からなる複数のコイルセグメントと、Ag含有材料からなる中継セグメントとを有する積層インダクタが提供される。ここで、軟磁性合金粒子の周囲の少なくとも一部には軟磁性合金が酸化してなる酸化被膜が存在する。磁性体層と前記コイルセグメントとは交互に積層された積層構造を構成し、中継セグメントは磁性体層を貫通してコイルセグメント間を導通するように形成され、コイルセグメントおよび中継セグメントは電気的に一体化した内部導体を構成する。コイルセグメントに挟まれた磁性体層中にAg不存在の層状領域が存在する。本発明によれば、内部導体の周辺の磁性体層中にあるAg粒子、及び/又は、前記軟磁体層に内部導体から伸びたAgからなる凸状部が存在する。
好ましくは、Ag不存在の層状領域の厚さが3μm以上である。
別途好ましくは、軟磁性合金粒子がFe-Si-M系軟磁性合金(但し、MはFeより酸化し易い金属元素である。)であり、隣接する軟磁性合金粒子の周囲に形成された酸化被膜を介しての結合部および酸化被膜が存在しない金属部分における軟磁性合金粒子どうしの結合部が存在する。 As a result of intensive studies by the present inventors, the invention of a multilayer inductor having the following characteristics has been completed. According to the present invention, there is provided a multilayer inductor having a plurality of magnetic layers made of soft magnetic alloy particles, a plurality of coil segments made of Ag-containing material, and a relay segment made of Ag-containing material. Here, at least a part of the periphery of the soft magnetic alloy particles has an oxide film formed by oxidizing the soft magnetic alloy. The magnetic layer and the coil segment constitute a laminated structure in which the coil segments are alternately stacked, the relay segment is formed so as to pass through the magnetic layer, and the coil segment and the relay segment are electrically connected. Constructs an integrated internal conductor. There is a layered region in the absence of Ag in the magnetic layer sandwiched between the coil segments. According to the present invention, there are Ag particles in the magnetic layer around the inner conductor and / or a convex portion made of Ag extending from the inner conductor in the soft magnetic layer.
Preferably, the thickness of the Ag-free layered region is 3 μm or more.
Separately, preferably, the soft magnetic alloy particles are Fe-Si-M based soft magnetic alloys (where M is a metal element that is easier to oxidize than Fe), and an oxidation formed around adjacent soft magnetic alloy particles. There are joints through the coating and joints between the soft magnetic alloy particles in the metal part where there is no oxide coating.
好ましくは、Ag不存在の層状領域の厚さが3μm以上である。
別途好ましくは、軟磁性合金粒子がFe-Si-M系軟磁性合金(但し、MはFeより酸化し易い金属元素である。)であり、隣接する軟磁性合金粒子の周囲に形成された酸化被膜を介しての結合部および酸化被膜が存在しない金属部分における軟磁性合金粒子どうしの結合部が存在する。 As a result of intensive studies by the present inventors, the invention of a multilayer inductor having the following characteristics has been completed. According to the present invention, there is provided a multilayer inductor having a plurality of magnetic layers made of soft magnetic alloy particles, a plurality of coil segments made of Ag-containing material, and a relay segment made of Ag-containing material. Here, at least a part of the periphery of the soft magnetic alloy particles has an oxide film formed by oxidizing the soft magnetic alloy. The magnetic layer and the coil segment constitute a laminated structure in which the coil segments are alternately stacked, the relay segment is formed so as to pass through the magnetic layer, and the coil segment and the relay segment are electrically connected. Constructs an integrated internal conductor. There is a layered region in the absence of Ag in the magnetic layer sandwiched between the coil segments. According to the present invention, there are Ag particles in the magnetic layer around the inner conductor and / or a convex portion made of Ag extending from the inner conductor in the soft magnetic layer.
Preferably, the thickness of the Ag-free layered region is 3 μm or more.
Separately, preferably, the soft magnetic alloy particles are Fe-Si-M based soft magnetic alloys (where M is a metal element that is easier to oxidize than Fe), and an oxidation formed around adjacent soft magnetic alloy particles. There are joints through the coating and joints between the soft magnetic alloy particles in the metal part where there is no oxide coating.
本発明によれば、Ag粒子が内部導体の近傍の磁性体層中に存在し、及び/又は、前記軟磁体層に内部導体から伸びたAgからなる凸状部が存在しているため、ヒートサイクルに供したときであっても内部導体と磁性体層との間に熱膨張差が生じにくく、内部導体と磁性体層との密着性があがり、結果的に導通不良が軽減する。好適態様においては、軟磁性合金粒子の周囲にある酸化被膜が大きな凹凸を有しており、Agのマイグレーションが抑制され、耐湿負荷をかけても信頼性が低下しにくい。
According to the present invention, the Ag particles are present in the magnetic layer in the vicinity of the inner conductor and / or the soft magnetic layer has a convex portion made of Ag extending from the inner conductor. Even when it is subjected to a cycle, a difference in thermal expansion hardly occurs between the inner conductor and the magnetic layer, and the adhesion between the inner conductor and the magnetic layer is improved. As a result, poor conduction is reduced. In a preferred embodiment, the oxide film around the soft magnetic alloy particles has large irregularities, Ag migration is suppressed, and reliability is unlikely to deteriorate even when a moisture resistance load is applied.
以下、図面を適宜参照しながら本発明を詳述する。但し、本発明は図示された態様に限定されるわけでなく、また、図面においては発明の特徴的な部分を強調して表現することがあるので、図面各部において縮尺の正確性は必ずしも担保されていない。
Hereinafter, 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.
図1(a)は積層インダクタの模式的な断面図である。図1(b)は図1(a)の部分拡大図である。本発明の対象である積層インダクタ1は、内部導体20の大部分が磁性体部(磁性体層10の積層体)の中に埋没している構造を有する。典型的には、内部導体20は螺旋状に形成されたコイルであり、その他、渦巻き状のコイル、ミアンダ(蛇行)状の導線、あるいは直線状の導線等が挙げられる。
FIG. 1A is a schematic cross-sectional view of a multilayer inductor. FIG.1 (b) is the elements on larger scale of Fig.1 (a). The multilayer inductor 1 that is the subject of the present invention has a structure in which most of the inner conductor 20 is buried in a magnetic part (laminate of the magnetic layer 10). Typically, the inner conductor 20 is a coil formed in a spiral shape, and other examples include a spiral coil, a meander (meandering) conductor, a linear conductor, and the like.
内部導体20はコイルセグメント21と中継セグメント22とを有する。コイルセグメント21と磁性体層10とは交互に積層された積層構造を構成する。中継セグメント22は磁性体層10を貫通するように形成されている。中継セグメント22は複数のコイルセグメント21どうしを導通するように形成されている。図2は典型的な積層インダクタの模式的な分解図である。図示された態様では、内部導体20は、コイルセグメントCS1~CS5と、このコイルセグメントCS1~CS5を接続する中継セグメントIS1~IS4とが、螺旋状に一体化したコイルの構造を有しており、コイルセグメントCS1~CS4はコ字状を成し、コイルセグメントCS5は帯状を成しており、各中継セグメントIS1~IS4は磁性体層ML1~ML4を貫通した柱状を成している。
The inner conductor 20 has a coil segment 21 and a relay segment 22. The coil segment 21 and the magnetic layer 10 constitute a laminated structure in which they are alternately laminated. The relay segment 22 is formed so as to penetrate the magnetic layer 10. The relay segment 22 is formed so as to conduct the plurality of coil segments 21. FIG. 2 is a schematic exploded view of a typical multilayer inductor. In the illustrated embodiment, the internal conductor 20 has a coil structure in which coil segments CS1 to CS5 and relay segments IS1 to IS4 connecting the coil segments CS1 to CS5 are spirally integrated. The coil segments CS1 to CS4 have a U shape, the coil segment CS5 has a strip shape, and each relay segment IS1 to IS4 has a column shape penetrating the magnetic layers ML1 to ML4.
本発明によれば、コイルセグメント21と中継セグメント22とはAg含有材料からなる。Ag含有材料は、典型的には、他の金属を実質的に含まぬAgであり、100重量部のAgと50重量部以下の他の金属との混合物や合金であってもよく、前記他の金属としては、Au、Cu、Pt、Pdなどが非限定的に例示される。
According to the present invention, the coil segment 21 and the relay segment 22 are made of an Ag-containing material. The Ag-containing material is typically Ag substantially free of other metals, and may be a mixture or alloy of 100 parts by weight of Ag and 50 parts by weight or less of other metals. Examples of the metal include, but are not limited to, Au, Cu, Pt, and Pd.
図1(b)は、2つのコイルセグメント21とそれらに挟まれる磁性体層10との模式的な拡大図である。図1(a)とは異なり、図1(b)では磁性体層10を示すハッチングの表記を省略している。本発明によれば、内部導体20の周辺の磁性体層10中にAg粒子30、及び/又は、軟磁体層10に内部導体20から伸びたAgからなる凸状部31、が存在している。図示された態様では、上記Ag粒子30と凸状部31の両方が存在している。Ag粒子30は、好ましくは、内部導体20の周辺の磁性体層10中の軟磁性合金粒子間に不連続的に存在するAgからなる。凸状部31は、好ましくは、内部導体20から内部導体20の周辺の磁性体層10中の軟磁性合金粒子間まで連続的に存在するAgからなる。図1(b)では内部導体20の一部としてコイルセグメント21が描写されているが、中継セグメントの近傍にもAg粒子、及び/又は、中継セグメントから伸びたAgからなる凸状部、が存在することが好ましい。このAg粒子30や凸状部31は例えば内部電極20を構成するAg含有材料に由来するものである。典型的には、内部導体20を構成するAg含有材料からAgが「拡散」して、Ag粒子30や凸状部31が存在するに至ったものである。
FIG. 1B is a schematic enlarged view of two coil segments 21 and a magnetic layer 10 sandwiched between them. Unlike FIG. 1A, in FIG. 1B, the hatching notation indicating the magnetic layer 10 is omitted. According to the present invention, there are Ag particles 30 in the magnetic layer 10 around the inner conductor 20 and / or convex portions 31 made of Ag extending from the inner conductor 20 in the soft magnetic layer 10. . In the illustrated embodiment, both the Ag particles 30 and the convex portions 31 are present. The Ag particles 30 are preferably made of Ag present discontinuously between the soft magnetic alloy particles in the magnetic layer 10 around the inner conductor 20. The convex portion 31 is preferably made of Ag that continuously exists between the inner conductor 20 and the soft magnetic alloy particles in the magnetic layer 10 around the inner conductor 20. Although the coil segment 21 is depicted as a part of the inner conductor 20 in FIG. 1B, Ag particles and / or convex portions made of Ag extending from the relay segment also exist in the vicinity of the relay segment. It is preferable to do. The Ag particles 30 and the convex portions 31 are derived from, for example, an Ag-containing material constituting the internal electrode 20. Typically, Ag “diffuses” from the Ag-containing material constituting the inner conductor 20, and the Ag particles 30 and the convex portions 31 exist.
ここで、上記「拡散」についての詳細な説明は、以下のとおりである。
磁性体層10は軟磁性合金粒子が多数集積して形成されている。そして、軟磁性合金粒子の間には空隙が形成されている。内部導体20の周辺の磁性体層10にも空隙が存在する。内部導体20を構成するAgの一部は、周辺の磁性体層10の空隙に入り込む。このような状態をここでは「拡散」と呼ぶことにする。 Here, the detailed description of the “diffusion” is as follows.
Themagnetic layer 10 is formed by accumulating a large number of soft magnetic alloy particles. In addition, voids are formed between the soft magnetic alloy particles. There are also air gaps in the magnetic layer 10 around the inner conductor 20. A part of Ag constituting the inner conductor 20 enters a gap in the peripheral magnetic layer 10. Such a state is referred to herein as “diffusion”.
磁性体層10は軟磁性合金粒子が多数集積して形成されている。そして、軟磁性合金粒子の間には空隙が形成されている。内部導体20の周辺の磁性体層10にも空隙が存在する。内部導体20を構成するAgの一部は、周辺の磁性体層10の空隙に入り込む。このような状態をここでは「拡散」と呼ぶことにする。 Here, the detailed description of the “diffusion” is as follows.
The
Ag粒子30、及び/又は、凸状部31が存在することにより、ヒートサイクル時の内部導体20と磁性体層10との間に熱膨張差が生じにくく、内部導体20と磁性体層10との密着性があがり、結果的に導通不良が軽減する。磁性体層10中において、Ag粒子30、及び/又は、凸状部31が存在することは、例えば、積層インダクタ1の断面を走査型電子顕微鏡(SEM)を用いて撮影して、その後、エネルギー分散型X線分析(EDS)によるZAF法で化学組成を求めることにより確認することができる。Ag粒子30の大きさ(球相当径)は特に限定なく、好ましくは1~10μmである。Ag粒子30は磁性体層10を構成する軟磁性合金粒子どうしの間の空隙を占めることが好ましい。Ag粒子30は個々の軟磁性合金粒子の周囲にある酸化被膜(図示せず)の中に存在していてもよい。
Due to the presence of the Ag particles 30 and / or the convex portions 31, a difference in thermal expansion hardly occurs between the inner conductor 20 and the magnetic layer 10 during the heat cycle, and the inner conductor 20 and the magnetic layer 10 As a result, poor conduction is reduced. The presence of the Ag particles 30 and / or the convex portions 31 in the magnetic layer 10 means that, for example, a cross section of the multilayer inductor 1 is photographed using a scanning electron microscope (SEM), and then energy is consumed. This can be confirmed by obtaining the chemical composition by the ZAF method by dispersive X-ray analysis (EDS). The size (equivalent sphere diameter) of the Ag particles 30 is not particularly limited, and is preferably 1 to 10 μm. It is preferable that the Ag particles 30 occupy voids between the soft magnetic alloy particles constituting the magnetic layer 10. The Ag particles 30 may be present in an oxide film (not shown) around the individual soft magnetic alloy particles.
本発明によれば、コイルセグメント21に挟まれた磁性体層10中にAg不存在の層状領域11が存在する。当該層状領域11は、図1(b)に模式的に記載されるように、内部導体20そのものの一部であるAgも、内部導体20から離れて磁性体層10中にあるAg粒子30も、上述の凸状部31も、いずれも存在しない層状の領域を意味する。このような層状領域11が存在することは、Agの拡散が磁性体層10の全域にわたっているわけではないことを意味しており、そのため、不所望な初期層間短絡が生じにくくなる。図中、点線で示されるように、Ag不存在の層状領域11の境界はコイルセグメント21と略平行になるように定める。Ag不存在の層状領域11の層の厚さは好ましくは3μm以上であり、より好ましくは5~25μmである。
According to the present invention, the Ag-free layered region 11 exists in the magnetic layer 10 sandwiched between the coil segments 21. As schematically shown in FIG. 1B, the layered region 11 includes Ag that is a part of the inner conductor 20 itself, and Ag particles 30 that are separated from the inner conductor 20 and are in the magnetic layer 10. The above-mentioned convex part 31 also means a layered region where none exists. The existence of such a layered region 11 means that the diffusion of Ag does not extend over the entire area of the magnetic layer 10, and therefore, an undesirable initial interlayer short circuit is less likely to occur. In the figure, as indicated by a dotted line, the boundary of the layer region 11 in the absence of Ag is determined to be substantially parallel to the coil segment 21. The layer thickness of the layer region 11 in the absence of Ag is preferably 3 μm or more, more preferably 5 to 25 μm.
本発明によれば、積層インダクタ1では、軟磁性合金粒子が多数集積して所定形状の磁性体部を構成している。磁性体部は、コイルセグメント21によって分断された磁性体層10の集合であると評価することができ、同時に、磁性体層10とコイルセグメント21とが積層構造を構成していると評価することができる。個々の軟磁性合金粒子はその周囲の少なくとも一部、好ましくは概ね全体にわたって酸化被膜が形成されていて、この酸化被膜により磁性体部の絶縁性が確保される。隣接する軟磁性合金粒子どうしは、概ね、それぞれの軟磁性合金粒子がもつ酸化被膜を介して結合することにより、一定の形状を有する磁性体部を構成している。酸化被膜は好ましくは難治性合金粒子それ自身が酸化してなる被膜である。部分的には、隣接する軟磁性合金粒子の金属部分どうしが結合していてもよい。また、内部導体20の近傍では、主に上記酸化被膜を介して、軟磁性合金粒子と内部導体20とが密着している。軟磁性合金粒子は好ましくはFe-M-Si系合金(但し、Mは鉄より酸化し易い金属である。)からなり、その場合、酸化被膜は好ましくはこの軟磁性合金が酸化してなるものであって磁性体であるFe3O4と、非磁性体であるFe2O3及びMOx(xは金属Mの酸化数に応じて決まる値である。)を少なくとも含むことが確認されている。
According to the present invention, in the multilayer inductor 1, a large number of soft magnetic alloy particles are accumulated to constitute a magnetic part having a predetermined shape. The magnetic body portion can be evaluated as an assembly of the magnetic layer 10 divided by the coil segment 21, and at the same time, it is evaluated that the magnetic layer 10 and the coil segment 21 constitute a laminated structure. Can do. Each of the soft magnetic alloy particles has an oxide film formed on at least a part of the periphery thereof, preferably substantially the whole, and this oxide film ensures the insulation of the magnetic part. Adjacent soft magnetic alloy particles are generally bonded via an oxide film of each soft magnetic alloy particle to constitute a magnetic part having a certain shape. The oxide film is preferably a film formed by oxidizing the refractory alloy particles themselves. In part, metal portions of adjacent soft magnetic alloy particles may be bonded to each other. Further, in the vicinity of the inner conductor 20, the soft magnetic alloy particles and the inner conductor 20 are in close contact mainly through the oxide film. The soft magnetic alloy particles are preferably made of an Fe-M-Si alloy (where M is a metal that is easier to oxidize than iron). In this case, the oxide film is preferably formed by oxidation of the soft magnetic alloy. It is confirmed that it contains at least Fe 3 O 4 that is a magnetic material, Fe 2 O 3 that is a non-magnetic material, and MO x (x is a value determined according to the oxidation number of the metal M). Yes.
上述の酸化被膜を介した結合の存在は、例えば、約3000倍に拡大したSEM観察像などにおいて、隣接する軟磁性合金粒子が有する酸化被膜が同一相であることを視認することなどで、明確に判断することができる。酸化被膜を介した結合の存在により、積層インダクタ1における機械的強度と絶縁性の向上が図られる。また、酸化被膜は通常は凹凸が比較的大きいので、Agのマイグレーションが抑制され、耐湿性が向上する。積層インダクタ1の全体にわたって、隣接する軟磁性合金粒子が有する酸化被膜を介して結合していることが好ましいが、一部でも結合していれば、相応の機械的強度と絶縁性の向上が図られ、そのような形態も本発明の一態様であるといえる。
The presence of the bond through the oxide film described above is clear, for example, by visually confirming that the oxide film of the adjacent soft magnetic alloy particles is in the same phase in an SEM observation image magnified about 3000 times. Can be judged. The presence of the bond through the oxide film improves the mechanical strength and insulation of the multilayer inductor 1. Moreover, since the oxide film usually has relatively large irregularities, the migration of Ag is suppressed and the moisture resistance is improved. The multilayer inductor 1 is preferably bonded through the oxide film of the adjacent soft magnetic alloy particles. However, if even a part of the multilayer inductor 1 is bonded, the corresponding mechanical strength and insulation can be improved. Such a form is also an embodiment of the present invention.
同様に、上述の軟磁性合金粒子の酸化被膜が存在しない金属部分どうしの結合についても、例えば、約3000倍に拡大したSEM観察像などにおいて、隣接する軟磁性合金粒子どうしが同一相を保ちつつ結合点を有することを視認することなどにより、金属部分どうしの結合の存在を明確に判断することができる。軟磁性合金粒子どうしの結合の存在により透磁率のさらなる向上が図られる。ここで、「酸化被膜が存在しない金属部分どうしの結合部」とは、隣接する合金粒子がそれらの金属部分にて直接に接触している部分のことを意味し、例えば、厳密な意味での金属結合や、金属部分どうしが直接に接触して原子の交換が見られない態様や、それらの中間的な態様をも含む概念である。厳密な意味での金属結合とは、「原子が規則的にならんでいる」等の要件を充足することを意味する。
Similarly, with regard to the bonding between the metal portions where the oxide film of the soft magnetic alloy particles does not exist, the adjacent soft magnetic alloy particles maintain the same phase in, for example, an SEM observation image magnified about 3000 times. The presence of a bond between metal parts can be clearly determined by visually confirming that a bond point is present. The magnetic permeability can be further improved by the presence of the coupling between the soft magnetic alloy particles. Here, the “joint part between metal parts where no oxide film is present” means a part in which adjacent alloy particles are in direct contact with each other, for example, in a strict sense. It is a concept including a metal bond, a mode in which metal parts are in direct contact with each other, and an exchange of atoms is not seen, and an intermediate mode between them. The metal bond in the strict sense means that the requirement such as “the atoms are regularly arranged” is satisfied.
なお、隣接する軟磁性合金粒子が、酸化被膜を介した結合も、軟磁性金属粒子どうしの結合もいずれも存在せず単に物理的に接触又は接近するに過ぎない形態が部分的にあってもよい。
In addition, even if the soft magnetic alloy particles adjacent to each other are partially in contact with or in close proximity to each other without both the bond through the oxide film and the bond between the soft magnetic metal particles. Good.
積層インダクタ1において、内部導体20の両端は、典型的には、それぞれ引出導体(図示せず)を介して積層インダクタ1の外表面の相対向する端面に引き出され、外部端子(図示せず)に接続される。外部端子の構造や接続様式については従来技術を適宜援用することができる。
In the multilayer inductor 1, both ends of the inner conductor 20 are typically drawn to opposite end surfaces of the outer surface of the multilayer inductor 1 through lead conductors (not shown), respectively, and external terminals (not shown). Connected to. Conventional technology can be used as appropriate for the structure and connection mode of the external terminals.
以下、本発明に係る積層インダクタ1の典型的かつ非限定的な製造方法を説明する。積層インダクタ1の製造にあたっては、まず、ドクターブレードやダイコータ等の塗工機を用いて、予め用意した磁性体ペースト(スラリー)を、樹脂等からなるベースフィルムの表面に塗工する。これを熱風乾燥機等の乾燥機で乾燥してグリーンシートを得る。上記磁性体ペーストは、軟磁性合金粒子と、典型的には、バインダとしての高分子樹脂と、溶剤とを含む。
Hereinafter, a typical and non-limiting manufacturing method of the multilayer inductor 1 according to the present invention will be described. In manufacturing the multilayer inductor 1, first, a magnetic paste (slurry) prepared in advance is applied to the surface of a base film made of resin or the like using a coating machine such as a doctor blade or a die coater. This is dried with a dryer such as a hot air dryer to obtain a green sheet. The magnetic paste includes soft magnetic alloy particles, typically a polymer resin as a binder, and a solvent.
軟磁性合金粒子は、主として合金からなる軟磁性を呈する粒子である。合金の種類としては、Fe-M-Si系合金(但し、Mは鉄より酸化し易い金属である。)が挙げられる。Mとしては、Cr、Alなどが挙げられ、好ましくはCrである。軟磁性合金粒子としては、例えばアトマイズ法で製造される粒子が挙げられる。
Soft magnetic alloy particles are particles exhibiting soft magnetism mainly composed of an alloy. Examples of the alloy include Fe-M-Si alloys (where M is a metal that is easier to oxidize than iron). Examples of M include Cr and Al, and Cr is preferable. Examples of the soft magnetic alloy particles include particles produced by an atomizing method.
MがCrである場合、つまり、Fe-Cr-Si系合金におけるクロムの含有率は、好ましくは2~8wt%である。クロムの存在は、熱処理時に不動態を形成して過剰な酸化を抑制するとともに強度および絶縁抵抗を発現する点で好ましく、一方、磁気特性の向上の観点からはクロムが少ないことが好ましく、これらを勘案して上記好適範囲が提案される。
When M is Cr, that is, the chromium content in the Fe—Cr—Si alloy is preferably 2 to 8 wt%. The presence of chromium is preferable in that it forms a passive state during heat treatment to suppress excessive oxidation and develop strength and insulation resistance. On the other hand, from the viewpoint of improving magnetic properties, it is preferable that there is little chromium. The above preferred range is proposed in consideration.
Fe-Cr-Si系軟磁性合金におけるSiの含有率は、好ましくは1.5~7wt%である。Siの含有量が多ければ高抵抗・高透磁率という点で好ましく、Siの含有量が少なければ成形性が良好であり、これらを勘案して上記好適範囲が提案される。
The Si content in the Fe—Cr—Si soft magnetic alloy is preferably 1.5 to 7 wt%. A high Si content is preferable in terms of high resistance and high magnetic permeability, and a low Si content provides good moldability, and the above preferable range is proposed in consideration of these.
Fe-Cr-Si系合金において、SiおよびCr以外の残部は不可避不純物を除いて、鉄であることが好ましい。Fe、SiおよびCr以外に含まれていてもよい金属としては、アルミニウム、マグネシウム、カルシウム、チタン、マンガン、コバルト、ニッケル、銅などが挙げられ、非金属としてはリン、硫黄、カーボンなどが挙げられる。
In the Fe—Cr—Si based alloy, the remainder other than Si and Cr is preferably iron except for inevitable impurities. Examples of metals that may be contained in addition to Fe, Si, and Cr include aluminum, magnesium, calcium, titanium, manganese, cobalt, nickel, and copper, and examples of nonmetals include phosphorus, sulfur, and carbon. .
積層インダクタ1における各々の軟磁性合金粒子を構成する合金については、例えば、積層インダクタ1の断面を走査型電子顕微鏡(SEM)を用いて撮影して、その後、エネルギー分散型X線分析(EDS)によるZAF法で化学組成を算出することができる。
For an alloy constituting each soft magnetic alloy particle in the multilayer inductor 1, for example, a cross section of the multilayer inductor 1 is photographed using a scanning electron microscope (SEM), and then energy dispersive X-ray analysis (EDS). The chemical composition can be calculated by the ZAF method.
磁性体部10のための原料として用いる軟磁性合金粒子の粒子径は適宜選択することができ、典型的には、体積基準において、d50が好ましくは2~20μmであり、より好ましくは3~10μmである。軟磁性合金粒子のd50は、レーザ回折散乱法を利用した粒子径・粒度分布測定装置(例えば、日機装(株)製のマイクロトラック)を用いて測定される。軟磁性合金粒子を用いる積層インダクタ1においては、原料粒子としての軟磁性合金粒子の粒子サイズは、積層インダクタ10の磁性体部を構成する軟磁性合金粒子の粒子サイズと概ね等しいことが分かっている。
The particle diameter of the soft magnetic alloy particles used as a raw material for the magnetic body portion 10 can be appropriately selected. Typically, d50 is preferably 2 to 20 μm, more preferably 3 to 10 μm on a volume basis. It is. The d50 of the soft magnetic alloy particles is measured using a particle size / particle size distribution measuring device (for example, Microtrack manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method. In the multilayer inductor 1 using soft magnetic alloy particles, it is known that the particle size of the soft magnetic alloy particles as the raw material particles is approximately equal to the particle size of the soft magnetic alloy particles constituting the magnetic part of the multilayer inductor 10. .
上述の磁性体ペーストには、好適にはバインダとしての高分子樹脂が含まれる。高分子樹脂の種類は特に限定はなく、例えば、ポリビニルブチラール(PVB)等のポリビニルアセタール樹脂などが挙げられる。磁性体ペーストの溶剤の種類は特に限定はなく、例えば、ブチルカルビトール等のグリコールエーテルなどを用いることができる。磁性体ペーストにおける軟磁性合金粒子、高分子樹脂、溶剤などの配合比率などは適宜調節することができ、それによって、磁性体ペーストの粘度などを設定することも可能である。
The above-mentioned magnetic paste preferably contains a polymer resin as a binder. The type of the polymer resin is not particularly limited, and examples thereof include polyvinyl acetal resins such as polyvinyl butyral (PVB). The type of solvent for the magnetic paste is not particularly limited, and for example, glycol ethers such as butyl carbitol can be used. The blending ratio of soft magnetic alloy particles, polymer resin, solvent and the like in the magnetic paste can be adjusted as appropriate, and the viscosity of the magnetic paste can be set accordingly.
磁性体ペーストを塗工および乾燥してグリーンシートを得るための具体的な方法は従来技術を適宜援用することができる。
Conventional techniques can be appropriately used as a specific method for obtaining a green sheet by applying and drying a magnetic paste.
次いで、打ち抜き加工機やレーザ加工機等の穿孔機を用いて、グリーンシートに穿孔を行ってスルーホール(貫通孔)を所定配列で形成する。スルーホールの配列については、各シートを積層したときに、導体を充填したスルーホール(即ち、中継セグメント22)とコイルセグメント21とで内部導体20が形成されるように設定される。内部導体を形成するためのスルーホールの配列およびコイルセグメント形成のための導体パターンの形状については、従来技術を適宜援用することができ、また、後述の実施例において図面を参照しながら具体例が説明される。
Next, using a punching machine such as a punching machine or a laser processing machine, the green sheet is punched to form through holes (through holes) in a predetermined arrangement. The arrangement of the through holes is set so that when the sheets are laminated, the internal conductor 20 is formed by the through hole (that is, the relay segment 22) filled with the conductor and the coil segment 21. As for the arrangement of the through holes for forming the inner conductor and the shape of the conductor pattern for forming the coil segment, conventional techniques can be used as appropriate, and specific examples are described with reference to the drawings in the following embodiments. Explained.
スルーホールに充填するため、および、導体パターンの印刷のために、好ましくは導体ペーストが使用される。導体ペーストにはAg含有材料と、典型的にはバインダとしての高分子樹脂と溶剤とが含まれる。
∙ Conductor paste is preferably used for filling the through holes and for printing the conductor pattern. The conductor paste contains an Ag-containing material, typically a polymer resin as a binder, and a solvent.
導体粒子としてのAg含有材料の粒子径は適宜選択することができ、体積基準において、d50が好ましくは1~10μmである。導体粒子のd50は、レーザ回折散乱法を利用した粒子径・粒度分布測定装置(例えば、日機装(株)製のマイクロトラック)を用いて測定される。
The particle diameter of the Ag-containing material as the conductor particles can be appropriately selected, and d50 is preferably 1 to 10 μm on a volume basis. The d50 of the conductor particles is measured using a particle size / particle size distribution measuring apparatus (for example, Microtrack manufactured by Nikkiso Co., Ltd.) using a laser diffraction scattering method.
導体ペーストには、好適にはバインダとしての高分子樹脂が含まれる。高分子樹脂の種類は特に限定はなく、例えば、ポリビニルブチラール(PVB)等のポリビニルアセタール樹脂などが挙げられる。導体ペーストの溶剤の種類は特に限定はなく、例えば、ブチルカルビトール等のグリコールエーテルなどを用いることができる。導体ペーストにおけるAg含有材料、高分子樹脂、溶剤などの配合比率などは適宜調節することができ、それによって、導体ペーストの粘度などを設定することも可能である。
The conductor paste preferably contains a polymer resin as a binder. The type of the polymer resin is not particularly limited, and examples thereof include polyvinyl acetal resins such as polyvinyl butyral (PVB). The kind of the solvent of the conductor paste is not particularly limited, and for example, glycol ether such as butyl carbitol can be used. The mixing ratio of Ag-containing material, polymer resin, solvent, etc. in the conductive paste can be adjusted as appropriate, and the viscosity of the conductive paste can be set accordingly.
次いで、スクリーン印刷機やグラビア印刷機等の印刷機を用いて、導体ペーストをグリーンシートの表面に印刷し、これを熱風乾燥機等の乾燥機で乾燥して、コイルセグメントに対応する導体パターンを形成する。印刷の際に、上述のスルーホールにも導体ペーストの一部が充填される。その結果、スルーホールに充填された導体ペーストと、印刷された導体パターンとが内部導体20の形状を構成することになる。
Next, using a printing machine such as a screen printing machine or a gravure printing machine, the conductor paste is printed on the surface of the green sheet, and this is dried with a dryer such as a hot air dryer to form a conductor pattern corresponding to the coil segment. Form. During printing, a part of the conductor paste is also filled in the above-described through hole. As a result, the conductor paste filled in the through hole and the printed conductor pattern constitute the shape of the internal conductor 20.
印刷後のグリーンシートを、吸着搬送機とプレス機を用いて、所定の順序で積み重ねて熱圧着して積層体を作製する。続いて、ダイシング機やレーザ加工機等の切断機を用いて、積層体を部品本体サイズに切断して、加熱処理前の磁性体部及び内部導体を含む、加熱処理前チップを作製する。
The green sheets after printing are stacked in a predetermined order using an adsorption conveyance machine and a press machine, and thermocompression bonded to produce a laminate. Subsequently, using a cutting machine such as a dicing machine or a laser processing machine, the multilayer body is cut into a component body size, and a pre-heat treatment chip including a magnetic body portion and an internal conductor before the heat treatment is manufactured.
焼成炉等の加熱装置を用いて、大気等の酸化性雰囲気中で、加熱処理前チップを加熱処理する。熱処理雰囲気は、酸化雰囲気であれば特に限定されず、生産面から考慮すると大気あるいは乾燥空気が望ましい。内部導体用のパターンからAgを磁性体層中に拡散させて、上述のAg粒子30や凸状部31を存在させやすくする観点から、昇温過程において好ましくは300~600℃にて、1~600分間保持し、その後、さらに温度を上げる。最高温度は、好ましくは600℃以上であり、より好ましくは700~900℃であり、最高温度において好ましくは、より詳細には0.5~3時間保持することが望ましい。
The chips before the heat treatment are heat-treated in an oxidizing atmosphere such as the air using a heating device such as a firing furnace. The heat treatment atmosphere is not particularly limited as long as it is an oxidizing atmosphere, and air or dry air is desirable in consideration of production. From the viewpoint of facilitating the presence of the Ag particles 30 and the convex portions 31 by diffusing Ag from the pattern for the inner conductor into the magnetic layer, the temperature is preferably increased from 300 to 600 ° C. for 1 to Hold for 600 minutes, then raise the temperature further. The maximum temperature is preferably 600 ° C. or higher, more preferably 700 to 900 ° C., and the maximum temperature is preferably maintained for 0.5 to 3 hours.
加熱処理前チップにあっては、個々の軟磁性合金粒子どうしの間に、多数の微細間隙が存在し、通常、該微細間隙は溶剤とバインダとの混合物で満たされている。これら混合物は昇温過程に消失し、該微細間隙はポアに変わる。上記最高温度に近い高温域では、軟磁性合金粒子が密集して磁性体部ができ、典型的には、その際に、軟磁性合金粒子それぞれの表面に酸化被膜が形成される。このとき、Ag含有材料が焼結して内部導体20が形成される。これにより積層インダクタ1が得られる。
In the pre-heat treatment chip, there are a large number of fine gaps between individual soft magnetic alloy particles, and the fine gaps are usually filled with a mixture of a solvent and a binder. These mixtures disappear during the heating process, and the fine gaps turn into pores. In the high temperature range close to the maximum temperature, the soft magnetic alloy particles are densely formed to form a magnetic part, and typically, an oxide film is formed on the surface of each soft magnetic alloy particle. At this time, the Ag-containing material is sintered to form the internal conductor 20. Thereby, the multilayer inductor 1 is obtained.
通常は、加熱処理の後に外部端子を形成する。ディップ塗布機やローラ塗布機等の塗布機を用いて、予め用意した導体ペーストを積層インダクタ1の長さ方向両端部に塗布し、これを焼成炉等の加熱装置を用いて、例えば、約600℃、約1hrの条件で焼付け処理を行うことにより、外部端子が形成される。外部端子用の導体ペーストは、上述した導体パターンの印刷用のペーストや、それに類似したペーストを適宜用いることができる。
Normally, external terminals are formed after heat treatment. Using a coating machine such as a dip coating machine or a roller coating machine, a conductor paste prepared in advance is applied to both ends in the length direction of the multilayer inductor 1, and this is applied using a heating device such as a firing furnace, for example, about 600. An external terminal is formed by performing a baking process at a temperature of about 1 hr. As the conductor paste for the external terminals, the above-described paste for printing a conductor pattern or a paste similar thereto can be used as appropriate.
以下、実施例により本発明をより具体的に説明する。ただし、本発明はこれらの実施例に記載された態様に限定されるわけではない。
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.
[積層インダクタの具体構造]
本実施例で製造した積層インダクタ1の具体構造例を説明する。部品としての積層インダクタ1は長さが約3.2mmで、幅が約1.6mmで、高さが約1.0mmで、全体が直方体形状を成している。 [Concrete structure of multilayer inductor]
A specific structural example of themultilayer inductor 1 manufactured in this embodiment will be described. The multilayer inductor 1 as a part has a length of about 3.2 mm, a width of about 1.6 mm, a height of about 1.0 mm, and the whole has a rectangular parallelepiped shape.
本実施例で製造した積層インダクタ1の具体構造例を説明する。部品としての積層インダクタ1は長さが約3.2mmで、幅が約1.6mmで、高さが約1.0mmで、全体が直方体形状を成している。 [Concrete structure of multilayer inductor]
A specific structural example of the
図2は積層インダクタの模式的な分解図である。内部導体が形成されている領域の磁性体部は、計5層の磁性体層ML1~ML5が一体化した構造を有する。内部導体が形成される領域を挟むように上部カバー領域および下部カバー領域が存在し、上部カバー領域は8層の磁性体層ML6が一体化した構造を有する。下部カバー領域は7層の磁性体層ML6が一体化した構造を有する。積層インダクタ1の長さは約3.2mm、幅は約1.6mm、高さは約1.0mmである。各磁性体層ML1~ML6の長さは約3.2mmで、幅は約1.6mmで、厚さは約30μmである。各磁性体層ML1~ML6は、軟磁性合金粒子である表1記載の組成、平均粒子径(d50)をもつ軟磁性合金粒子を主体として成形されてなり、ガラス成分を含んでいない。また、軟磁性合金粒子それぞれの表面には酸化被膜(図示せず)が存在し、磁性体部ならびに上部及び下部カバー領域内の軟磁性合金粒子は隣接する合金粒子それぞれが有する酸化被膜を介して相互結合していることを、本発明者らはSEM観察(3000倍)によって確認した。
FIG. 2 is a schematic exploded view of a multilayer inductor. The magnetic part in the region where the inner conductor is formed has a structure in which a total of five magnetic layers ML1 to ML5 are integrated. An upper cover region and a lower cover region exist so as to sandwich the region where the inner conductor is formed, and the upper cover region has a structure in which eight magnetic layers ML6 are integrated. The lower cover region has a structure in which seven magnetic layers ML6 are integrated. The length of the multilayer inductor 1 is about 3.2 mm, the width is about 1.6 mm, and the height is about 1.0 mm. Each of the magnetic layers ML1 to ML6 has a length of about 3.2 mm, a width of about 1.6 mm, and a thickness of about 30 μm. Each of the magnetic layers ML1 to ML6 is formed mainly of soft magnetic alloy particles having the composition and average particle diameter (d50) shown in Table 1 which are soft magnetic alloy particles, and does not contain a glass component. In addition, an oxide film (not shown) exists on the surface of each soft magnetic alloy particle, and the soft magnetic alloy particles in the magnetic body part and the upper and lower cover regions pass through the oxide film of each adjacent alloy particle. The present inventors confirmed that they were mutually bonded by SEM observation (3000 times).
内部導体20は、計5個のコイルセグメントCS1~CS5と、該コイルセグメントCS1~CS5を接続する計4個の中継セグメントIS1~IS4とが、螺旋状に一体化したコイルの構造を有する。この内部導体20は、銀粒子を熱処理して得られ、原料として用いた銀粒子の体積基準のd50は5μmである。なお比較例4のみ銀粒子の代わりに銅粒子を使用した。
The inner conductor 20 has a coil structure in which a total of five coil segments CS1 to CS5 and a total of four relay segments IS1 to IS4 connecting the coil segments CS1 to CS5 are spirally integrated. The inner conductor 20 is obtained by heat-treating silver particles, and the volume-based d50 of the silver particles used as a raw material is 5 μm. Only Comparative Example 4 used copper particles instead of silver particles.
4個のコイルセグメントCS1~CS4はコ字状を成し、1個のコイルセグメントCS5は帯状を成しており、各コイルセグメントCS1~CS5の厚さは約20μmで、幅は約0.2mmである。最上位のコイルセグメントCS1は、外部端子との接続に利用されるL字状の引出部分LS1を連続して有し、最下位のコイルセグメントCS5は、外部端子との接続に利用されるL字状の引出部分LS2を連続して有している。各中継セグメントIS1~IS4は磁性体層ML1~ML4を貫通した柱状を成しており、各々の口径は約15μmである。
The four coil segments CS1 to CS4 have a U shape, and the one coil segment CS5 has a strip shape. Each coil segment CS1 to CS5 has a thickness of about 20 μm and a width of about 0.2 mm. It is. The uppermost coil segment CS1 has a continuous L-shaped lead portion LS1 used for connection with an external terminal, and the lowermost coil segment CS5 is L-shaped used for connection with an external terminal. The lead-out portion LS2 is continuously formed. Each of the relay segments IS1 to IS4 has a column shape penetrating the magnetic layers ML1 to ML4, and each has a diameter of about 15 μm.
各外部端子(図示せず)は、積層インダクタ1の長さ方向の各端面と該端面近傍の4側面に及んでおり、その厚さは約20μmである。一方の外部端子は最上位のコイルセグメントCS1の引出部分LS1の端縁と接続し、他方の外部端子は最下位のコイルセグメントCS5の引出部分LS2の端縁と接続している。これら外部端子は、主として体積基準のd50が5μmである銀粒子を熱処理して得た。
Each external terminal (not shown) extends to each end face in the length direction of the multilayer inductor 1 and four side faces in the vicinity of the end face, and has a thickness of about 20 μm. One external terminal is connected to the edge of the lead portion LS1 of the uppermost coil segment CS1, and the other external terminal is connected to the edge of the lead portion LS2 of the lowermost coil segment CS5. These external terminals were obtained mainly by heat-treating silver particles having a volume-based d50 of 5 μm.
[積層インダクタの製造]
表1記載の軟磁性合金粒子85wt%、ブチルカルビトール(溶剤)が13wt%、ポリビニルブチラール(バインダ)2wt%からなる磁性体ペーストを調製した。ドクターブレードを用いて、この磁性体ペーストをプラスチック製のベースフィルムの表面に塗工し、これを熱風乾燥機で、約80℃、約5minの条件で乾燥した。このようにしてベースフィルム上にグリーンシートを得た。その後、グリーンシートをカットして、磁性体層ML1~ML6(図2を参照)に対応し、且つ、多数個取りに適合したサイズの第1~第6シートをそれぞれ得た。 [Manufacture of multilayer inductors]
A magnetic paste consisting of 85 wt% of soft magnetic alloy particles shown in Table 1, 13 wt% of butyl carbitol (solvent), and 2 wt% of polyvinyl butyral (binder) was prepared. Using a doctor blade, this magnetic paste was applied to the surface of a plastic base film, and this was dried with a hot air dryer at about 80 ° C. for about 5 minutes. In this way, a green sheet was obtained on the base film. Thereafter, the green sheet was cut to obtain first to sixth sheets corresponding to the magnetic layers ML1 to ML6 (see FIG. 2) and having a size suitable for multi-cavity.
表1記載の軟磁性合金粒子85wt%、ブチルカルビトール(溶剤)が13wt%、ポリビニルブチラール(バインダ)2wt%からなる磁性体ペーストを調製した。ドクターブレードを用いて、この磁性体ペーストをプラスチック製のベースフィルムの表面に塗工し、これを熱風乾燥機で、約80℃、約5minの条件で乾燥した。このようにしてベースフィルム上にグリーンシートを得た。その後、グリーンシートをカットして、磁性体層ML1~ML6(図2を参照)に対応し、且つ、多数個取りに適合したサイズの第1~第6シートをそれぞれ得た。 [Manufacture of multilayer inductors]
A magnetic paste consisting of 85 wt% of soft magnetic alloy particles shown in Table 1, 13 wt% of butyl carbitol (solvent), and 2 wt% of polyvinyl butyral (binder) was prepared. Using a doctor blade, this magnetic paste was applied to the surface of a plastic base film, and this was dried with a hot air dryer at about 80 ° C. for about 5 minutes. In this way, a green sheet was obtained on the base film. Thereafter, the green sheet was cut to obtain first to sixth sheets corresponding to the magnetic layers ML1 to ML6 (see FIG. 2) and having a size suitable for multi-cavity.
続いて、穿孔機を用いて、磁性体層ML1に対応する第1シートに穿孔を行い、中継セグメントIS1に対応する貫通孔を所定配列で形成した。同様に、磁性体層ML2~ML4に対応する第2~第4シートそれぞれに、中継セグメントIS2~IS4に対応する貫通孔を所定配列で形成した。
Subsequently, using a punch, the first sheet corresponding to the magnetic layer ML1 was punched to form through holes corresponding to the relay segment IS1 in a predetermined arrangement. Similarly, through holes corresponding to the relay segments IS2 to IS4 were formed in a predetermined arrangement in the second to fourth sheets corresponding to the magnetic layers ML2 to ML4, respectively.
続いて、印刷機を用いて、上記Ag粒子が85wt%で、ブチルカルビトール(溶剤)が13wt%で、ポリビニルブチラール(バインダ)が2wt%からなる導体ペーストを上記第1シートの表面に印刷し、これを熱風乾燥機で、約80℃、約5minの条件で乾燥して、コイルセグメントCS1に対応する第1印刷層を所定配列で作製した。同様に、上記第2~第5シートそれぞれの表面に、コイルセグメントCS2~CS5に対応する第2~第5印刷層を所定配列で作製した。
Subsequently, using a printing machine, a conductor paste consisting of 85 wt% of the Ag particles, 13 wt% of butyl carbitol (solvent), and 2 wt% of polyvinyl butyral (binder) is printed on the surface of the first sheet. Then, this was dried with a hot air dryer under conditions of about 80 ° C. and about 5 minutes, and a first printed layer corresponding to the coil segment CS1 was produced in a predetermined arrangement. Similarly, second to fifth printed layers corresponding to the coil segments CS2 to CS5 were formed in a predetermined arrangement on the surfaces of the second to fifth sheets.
第1~第4シートそれぞれに形成した貫通孔は、第1~第4印刷層それぞれの端部に重なる位置に存するため、第1~第4印刷層を印刷する際に導体ペーストの一部が各貫通孔に充填されて、中継セグメントIS1~IS4に対応する第1~第4充填部が形成される。
Since the through-holes formed in each of the first to fourth sheets are located at the positions overlapping the end portions of the first to fourth printed layers, a part of the conductor paste is formed when the first to fourth printed layers are printed. Filling each through hole, first to fourth filling portions corresponding to the relay segments IS1 to IS4 are formed.
続いて、吸着搬送機とプレス機を用いて、印刷層及び充填部が設けられた第1~第4シートと、印刷層のみが設けられた第5シートと、印刷層及び充填部が設けられていない第6シートとを、図2に示した順序で積み重ねて熱圧着して積層体を作製した。この積層体を切断機で部品本体サイズに切断して、加熱処理前チップを得た。
Subsequently, the first to fourth sheets provided with the printing layer and the filling unit, the fifth sheet provided only with the printing layer, and the printing layer and the filling unit are provided using an adsorption conveyance machine and a press. The 6th sheet | seat which has not been piled up in the order shown in FIG. 2, and thermocompression bonded, and the laminated body was produced. This laminated body was cut into a component body size with a cutting machine to obtain a chip before heat treatment.
続いて、焼成炉を用いて、大気中雰囲気で、加熱処理前チップを多数個一括で加熱処理した。まず、脱バインダプロセスとして約300℃、約1hrの条件で加熱し、次いで、後述する条件にしたがう加熱処理を施して、軟磁性合金粒子が密集して磁性体部10が形成し、また、銀粒子が焼結して内部導体20が形成され、これにより部品本体を得た。
Subsequently, a number of pre-heat-treated chips were heat-treated in a lump in an air atmosphere using a firing furnace. First, as a binder removal process, heating is performed under conditions of about 300 ° C. and about 1 hr, and then heat treatment is performed according to the conditions described later, so that the soft magnetic alloy particles are densely formed to form the magnetic body portion 10. The particles were sintered to form the inner conductor 20, thereby obtaining a component main body.
各実施例および比較例における熱処理条件は以下のとおりである。
共通事項:最高温度は700℃であり、この温度で1時間保持した。
実施例1では、昇温過程で600℃にて1時間保持した。
実施例2では、昇温過程で600℃にて3時間保持した。
実施例3では、昇温過程で600℃にて10時間保持した。
実施例4では、昇温過程で600℃にて3時間保持した。
比較例1では、昇温過程で600℃にて20時間保持した。
比較例2では、昇温過程での特定温度での保持を行わなかった。
比較例3では、昇温過程での特定温度での保持を行わなかった。
比較例4では、昇温過程で600℃にて1時間保持した。 The heat treatment conditions in each example and comparative example are as follows.
Common items: The maximum temperature was 700 ° C., and this temperature was maintained for 1 hour.
In Example 1, the temperature was maintained at 600 ° C. for 1 hour during the temperature rising process.
In Example 2, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process.
In Example 3, the temperature was maintained at 600 ° C. for 10 hours during the temperature raising process.
In Example 4, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process.
In Comparative Example 1, the temperature was maintained at 600 ° C. for 20 hours during the temperature raising process.
In Comparative Example 2, holding at a specific temperature during the temperature rising process was not performed.
In Comparative Example 3, holding at a specific temperature during the temperature rising process was not performed.
In Comparative Example 4, the temperature was kept at 600 ° C. for 1 hour during the temperature raising process.
共通事項:最高温度は700℃であり、この温度で1時間保持した。
実施例1では、昇温過程で600℃にて1時間保持した。
実施例2では、昇温過程で600℃にて3時間保持した。
実施例3では、昇温過程で600℃にて10時間保持した。
実施例4では、昇温過程で600℃にて3時間保持した。
比較例1では、昇温過程で600℃にて20時間保持した。
比較例2では、昇温過程での特定温度での保持を行わなかった。
比較例3では、昇温過程での特定温度での保持を行わなかった。
比較例4では、昇温過程で600℃にて1時間保持した。 The heat treatment conditions in each example and comparative example are as follows.
Common items: The maximum temperature was 700 ° C., and this temperature was maintained for 1 hour.
In Example 1, the temperature was maintained at 600 ° C. for 1 hour during the temperature rising process.
In Example 2, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process.
In Example 3, the temperature was maintained at 600 ° C. for 10 hours during the temperature raising process.
In Example 4, the temperature was maintained at 600 ° C. for 3 hours during the temperature raising process.
In Comparative Example 1, the temperature was maintained at 600 ° C. for 20 hours during the temperature raising process.
In Comparative Example 2, holding at a specific temperature during the temperature rising process was not performed.
In Comparative Example 3, holding at a specific temperature during the temperature rising process was not performed.
In Comparative Example 4, the temperature was kept at 600 ° C. for 1 hour during the temperature raising process.
続いて、外部端子を形成した。上記銀粒子を85wt%、ブチルカルビトール(溶剤)を13wt%で、ポリビニルブチラール(バインダ)を2wt%含有する導体ペーストを塗布機で、部品本体の長さ方向両端部に塗布し、これを焼成炉で、約600℃、約1hrの条件で焼付け処理を行った。その結果、溶剤及びバインダが消失し、銀粒子が焼結して、外部端子が形成され、積層インダクタ1を得た。
Subsequently, external terminals were formed. A conductive paste containing 85 wt% of the above silver particles, 13 wt% of butyl carbitol (solvent) and 2 wt% of polyvinyl butyral (binder) is applied to both ends in the longitudinal direction of the component body, and this is fired Baking treatment was performed in a furnace under conditions of about 600 ° C. and about 1 hr. As a result, the solvent and the binder disappeared, the silver particles were sintered, the external terminals were formed, and the multilayer inductor 1 was obtained.
[積層インダクタの評価]
Ag不存在の層状領域11の厚さを測定した。測定は断面のSEM像を用いて行い、1つの実施例・比較例について、20個の積層インダクタについてそれぞれ5層の厚さを測ることにより100個の測定データを取得し、表1にはその最小値を記載した。なお、2つのコイルセグメント間の距離は17.8μmであった。 [Evaluation of multilayer inductor]
The thickness of the layer region 11 in the absence of Ag was measured. The measurement was performed using the SEM image of the cross section, and for one example / comparative example, 100 measurement data were obtained by measuring the thickness of 5 layers for each of the 20 laminated inductors. The minimum value is listed. The distance between the two coil segments was 17.8 μm.
Ag不存在の層状領域11の厚さを測定した。測定は断面のSEM像を用いて行い、1つの実施例・比較例について、20個の積層インダクタについてそれぞれ5層の厚さを測ることにより100個の測定データを取得し、表1にはその最小値を記載した。なお、2つのコイルセグメント間の距離は17.8μmであった。 [Evaluation of multilayer inductor]
The thickness of the layer region 11 in the absence of Ag was measured. The measurement was performed using the SEM image of the cross section, and for one example / comparative example, 100 measurement data were obtained by measuring the thickness of 5 layers for each of the 20 laminated inductors. The minimum value is listed. The distance between the two coil segments was 17.8 μm.
得られた積層インダクタにおける信頼性を評価した。信頼性の評価は初期のQ値および耐湿負荷試験後のQ値であり、アジレント社製のインピーダンス・アナライザ4294Aを用いて、周波数1MHzで測定した。
当該初期値評価における評価指標は以下のとおりである。
○・・・Q値が40以上。
×・・・Q値が40未満。
-・・・インダクタとしてのQ値が得られなかった。 The reliability of the obtained multilayer inductor was evaluated. Reliability evaluation was an initial Q value and a Q value after a moisture resistance load test, and was measured at a frequency of 1 MHz using an impedance analyzer 4294A manufactured by Agilent.
The evaluation indexes in the initial value evaluation are as follows.
○ ・ ・ ・ Q value is 40 or more.
X ... Q value is less than 40.
-... The Q value as an inductor was not obtained.
当該初期値評価における評価指標は以下のとおりである。
○・・・Q値が40以上。
×・・・Q値が40未満。
-・・・インダクタとしてのQ値が得られなかった。 The reliability of the obtained multilayer inductor was evaluated. Reliability evaluation was an initial Q value and a Q value after a moisture resistance load test, and was measured at a frequency of 1 MHz using an impedance analyzer 4294A manufactured by Agilent.
The evaluation indexes in the initial value evaluation are as follows.
○ ・ ・ ・ Q value is 40 or more.
X ... Q value is less than 40.
-... The Q value as an inductor was not obtained.
得られた積層インダクタにおける、ヒートサイクル後の導通性を評価した。ヒートサイクルの条件は、55℃~125℃、保持時間30min(100サイクル)とした。その後の導通試験にて、導通が認められたものは○、導通しなかったものは×、初期のQ値が得られず未評価のものは-、と評価した。
The continuity after the heat cycle in the obtained multilayer inductor was evaluated. The heat cycle conditions were 55 ° C. to 125 ° C. and a holding time of 30 minutes (100 cycles). In a subsequent continuity test, the case where continuity was recognized was evaluated as ◯, the case where continuity was not achieved was evaluated as x, and the case where an initial Q value was not obtained and was not evaluated was evaluated as-.
得られた積層インダクタにおける、耐湿負荷試験後のQ値を測定した。耐湿負荷試験の条件は、60℃、95%RH、1.2A、1000hrとした。Q値の測定条件は初期のQ値の測定と同様である。当該評価による評価指標は以下のとおりである。
○・・・Q値の耐湿負荷試験前(初期値)からの変化率が絶対値で30%未満。
×・・・Q値の耐湿負荷試験前(初期値)からの変化率が絶対値で30%以上。
-・・・初期のQ値が得られず未評価。 The Q value after the moisture resistance load test in the obtained multilayer inductor was measured. The conditions of the moisture resistance load test were 60 ° C., 95% RH, 1.2 A, and 1000 hr. The measurement condition of the Q value is the same as the initial Q value measurement. The evaluation indexes based on the evaluation are as follows.
○: The rate of change of Q value from the humidity resistance load test (initial value) is less than 30% in absolute value.
X: The rate of change of the Q value from before the moisture resistance load test (initial value) is 30% or more in absolute value.
-... The initial Q value was not obtained and was not evaluated.
○・・・Q値の耐湿負荷試験前(初期値)からの変化率が絶対値で30%未満。
×・・・Q値の耐湿負荷試験前(初期値)からの変化率が絶対値で30%以上。
-・・・初期のQ値が得られず未評価。 The Q value after the moisture resistance load test in the obtained multilayer inductor was measured. The conditions of the moisture resistance load test were 60 ° C., 95% RH, 1.2 A, and 1000 hr. The measurement condition of the Q value is the same as the initial Q value measurement. The evaluation indexes based on the evaluation are as follows.
○: The rate of change of Q value from the humidity resistance load test (initial value) is less than 30% in absolute value.
X: The rate of change of the Q value from before the moisture resistance load test (initial value) is 30% or more in absolute value.
-... The initial Q value was not obtained and was not evaluated.
得られた積層インダクタについて、断面を走査型電子顕微鏡(SEM)を用いて撮影して、その後、エネルギー分散型X線分析(EDS)によるZAF法で化学組成を求めることにより、Ag粒子および上述した凸状部の存在の有無を調べた。実施例1~4および比較例1、2では、Ag粒子と上述した凸状部の両方が存在し、比較例3、4ではAg粒子も凸状部もいずれも存在しなかった。
About the obtained multilayer inductor, the cross section was photographed using a scanning electron microscope (SEM), and then the chemical composition was determined by the ZAF method by energy dispersive X-ray analysis (EDS), whereby the Ag particles and the above-described components were obtained. The presence or absence of convex portions was examined. In Examples 1 to 4 and Comparative Examples 1 and 2, both Ag particles and the above-mentioned convex portions were present, and in Comparative Examples 3 and 4, neither Ag particles nor convex portions were present.
比較例2以外の、全ての実施例及び比較例の積層インダクタの断面について、約3000倍に拡大したSEM観察像において、隣接する軟磁性合金粒子が有する酸化被膜はその大部分が同一相を呈することを視認した。同様の観察において、比較例2以外の、全ての実施例及び比較例の積層インダクタの断面について、軟磁性合金粒子の酸化被膜が存在しない金属部分どうしの結合が存在することを確認し、その結合においては、隣接する軟磁性合金粒子どうしが同一相を保ちつつ結合点を有することを視認した。
With respect to the cross-sections of the multilayer inductors of all Examples and Comparative Examples other than Comparative Example 2, in the SEM observation image magnified about 3000 times, most of the oxide films of the adjacent soft magnetic alloy particles exhibit the same phase. I visually confirmed that. In the same observation, it was confirmed that there was a bond between metal parts where no oxide film of soft magnetic alloy particles existed in the cross sections of the laminated inductors of all the examples and comparative examples other than Comparative Example 2, and the bonding In FIG. 5, it was visually confirmed that adjacent soft magnetic alloy particles have a bonding point while maintaining the same phase.
表1における「組成」の欄では、Fe-Cr-Siは、Crが4.5wt%、Siが3.5wt%、残部がFeであり、Fe-Si-Alは、Alが5.5wt%、Siが9.5wt%、残部がFeであり、Ni-ZnフェライトはNiOが11mol%、ZnOが20mol%、CuOが10mol%、Fe2O3が49mol%である。
In the column of “Composition” in Table 1, Fe—Cr—Si is 4.5 wt% Cr, 3.5 wt% Si, the balance is Fe, and Fe—Si—Al is 5.5 wt% Al. , Si is 9.5 wt%, the balance is Fe, Ni—Zn ferrite is 11 mol% NiO, 20 mol% ZnO, 10 mol% CuO, and 49 mol% Fe 2 O 3 .
各実施例では信頼性およびヒートサイクル後の導通性に優れていた。比較例1ではAgが磁性体層のほぼ全域に拡散しており、初期のQ値が低かったため、その後の評価を行うに値しなかった。比較例2では、Agがマイグレーションしており耐湿負荷後のQ値が低下し、信頼性が低かった。比較例3では、Ag粒子が磁性体層に存在せず、ヒートサイクル時に内部電線と磁性体層との熱膨張差によると思われる剥離が生じて、剥離した脆弱な部分の断線を招き、導通性が悪化した。比較例4では銅が酸化して初期のQ値が低かったため、その後の評価を行うに値しなかった。
Each example was excellent in reliability and conductivity after heat cycle. In Comparative Example 1, Ag diffused almost throughout the magnetic layer, and the initial Q value was low, so that it was not worth performing the subsequent evaluation. In Comparative Example 2, Ag migrated, the Q value after moisture resistance load decreased, and the reliability was low. In Comparative Example 3, the Ag particles are not present in the magnetic layer, and during the heat cycle, peeling that seems to be due to the difference in thermal expansion between the internal electric wire and the magnetic layer occurs, leading to disconnection of the peeled fragile portion, and conduction. Sex deteriorated. In Comparative Example 4, since copper was oxidized and the initial Q value was low, it was not worth performing the subsequent evaluation.
本発明によれば、電子部品の分野における積層インダクタのさらなる小型化および高性能化が達成することが期待される。本明細書では特定の実施形態について記述したが、添付の請求項にて定めた本発明の範囲内で、上記デバイスおよび技術について種々の改変や置換が存在することが当業者には理解されよう。
According to the present invention, it is expected to achieve further miniaturization and higher performance of the multilayer inductor in the field of electronic components. While specific embodiments have been described herein, those skilled in the art will recognize that various modifications and substitutions exist for the above devices and techniques within the scope of the present invention as defined in the appended claims. .
1 積層インダクタ、10 磁性体層、11 Ag不存在の層状領域、20 内部導体、21 コイルセグメント、22 中継セグメント、30 Ag粒子、31 凸状部、ML1~ML6 磁性体層、CS1~CS5 コイルセグメント、IS1~IS4 中継セグメント
1 laminated inductor, 10 magnetic layer, 11 Ag layered area, 20 inner conductor, 21 coil segment, 22 relay segment, 30 Ag particle, 31 convex part, ML1-ML6 magnetic layer, CS1-CS5 coil segment , IS1-IS4 relay segment
Claims (3)
- 軟磁性合金粒子で形成された複数の磁性体層と、Ag含有材料からなる複数のコイルセグメントと、Ag含有材料からなる中継セグメントとを有し、前記軟磁性合金粒子の周囲の少なくとも一部には前記軟磁性合金が酸化してなる酸化被膜が存在し、前記磁性体層と前記コイルセグメントとは交互に積層された積層構造を構成し、前記中継セグメントは前記磁性体層を貫通して前記コイルセグメント間を導通するように形成され、前記コイルセグメントおよび中継セグメントは電気的に一体化した内部導体を構成し、前記コイルセグメントに挟まれた磁性体層中にAg不存在の層状領域が存在し、かつ少なくとも下記(A)または(B)の一方が存在する、積層インダクタ。
(A)前記内部導体の周辺の磁性体層中にあるAg粒子
(B)前記軟磁体層に内部導体から伸びたAgからなる凸状部 A plurality of magnetic layers made of soft magnetic alloy particles, a plurality of coil segments made of Ag-containing material, and a relay segment made of Ag-containing material, and at least part of the periphery of the soft magnetic alloy particles Has an oxide film formed by oxidation of the soft magnetic alloy, and constitutes a laminated structure in which the magnetic layer and the coil segment are alternately laminated, and the relay segment penetrates the magnetic layer and passes through the magnetic layer. The coil segment and the relay segment are formed as an electrically conductive inner conductor, and there is a layered region in the absence of Ag in the magnetic layer sandwiched between the coil segments. And at least one of the following (A) or (B):
(A) Ag particles in the magnetic layer around the inner conductor (B) Convex portion made of Ag extending from the inner conductor to the soft magnetic layer - 前記Ag不存在の層状領域の厚さが3μm以上である請求項1記載の積層インダクタ。 The multilayer inductor according to claim 1, wherein the thickness of the layered region where Ag is absent is 3 µm or more.
- 前記軟磁性合金粒子がFe-Si-M系軟磁性合金(但し、MはFeより酸化し易い金属元素である。)であり、隣接する軟磁性合金粒子の周囲に形成された酸化被膜を介しての結合部および酸化被膜が存在しない金属部分における軟磁性合金粒子どうしの結合部を有する、請求項1又は2記載の積層インダクタ。 The soft magnetic alloy particles are Fe-Si-M soft magnetic alloys (where M is a metal element that is easier to oxidize than Fe), and through an oxide film formed around adjacent soft magnetic alloy particles. 3. The multilayer inductor according to claim 1, further comprising a coupling portion between soft magnetic alloy particles in a metal portion where no coupling portion and no oxide film exist.
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