Laminated coil components

Abstract

A laminated coil component is provided that can suppress the generation of cracks in an external electrode during sintering. The laminated coil component (1) is characterized by comprising a laminate (10) formed by laminating a plurality of insulating layers (31) in a lamination direction and having a coil (30) disposed therein, and external electrodes (21, 22) disposed on a surface of the laminate (10) and electrically connected to the coil (30), wherein the insulating layer (31) comprises a ferrite phase having a spinel structure and a ZnFe(BO3)O type crystalline phase.

Description

Technical Field

[0001] The present invention relates to a laminated coil component. Background Art

[0002] Patent Document 1 discloses a laminated coil component having excellent high-frequency characteristics using a base body including a magnetic portion containing glass and ferrite.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-212372

[0004] However, in the laminated coil component described in Patent Document 1, due to the difference in linear expansion coefficient between the conductor portion (silver) buried in the magnetic body and the material constituting the magnetic body, there is a concern that the stress of the external electrode (base electrode) during sintering increases, causing cracks.

[0005] Glass has lower flexural strength than ferrite, so this problem becomes more pronounced compared to a case where the magnetic body is 100% ferrite. Summary of the Invention

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laminated coil component capable of suppressing the occurrence of cracks in external electrodes during sintering.

[0007] The stacked coil component of the present invention is characterized in that it has a stacked body formed by stacking multiple insulating layers in the stacking direction and with a coil arranged inside, and an external electrode arranged on the surface of the above-mentioned stacked body and electrically connected to the above-mentioned coil, and the above-mentioned insulating layer contains a ferrite phase with a spinel structure and a ZnFe(BO3)O type crystalline phase.

[0008] According to the present invention, it is possible to provide a laminated coil component capable of suppressing the occurrence of cracks in the external electrodes during sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view schematically showing an example of the laminated coil component of the present invention.

[0010] Figure 2 It is a cross-sectional view schematically showing an example of the laminated coil component of the present invention.

[0011] Figure 3 It schematically represents the composition Figure 2 Schematic exploded perspective view of the insulating layer of the laminated coil component shown.

[0012] Figure 4 It schematically represents the composition Figure 2 Schematic diagram of an exploded plan view of the insulating layer of the laminated coil component shown.

[0013] Figure 5 The X-ray diffraction pattern of the sample prepared in Example 6 is shown.

[0014] Figure 6 This is a graph showing the linear expansion coefficients at 700° C. of samples prepared in Examples 1 to 12 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0015] Hereinafter, the laminated coil component of the present invention will be described.

[0016] However, the present invention is not limited to the following structures and modes, and can be applied with appropriate changes within the scope of the present invention. In addition, the present invention also includes a combination of two or more of the preferred structures and modes of the present invention described below.

[0017] Figure 1 It is a perspective view schematically showing an example of the laminated coil component of the present invention.

[0018] Figure 1 The illustrated laminated coil component 1 includes a laminate 10, a first external electrode 21, and a second external electrode 22. The laminate 10 is, for example, a roughly six-sided rectangular parallelepiped. While the structure of the laminate 10 will be described later, it is comprised of multiple insulating layers stacked in the stacking direction, with a coil disposed therein. The first external electrode 21 and the second external electrode 22 are each electrically connected to the coil.

[0019] In the laminated coil component and the laminated body in this specification, the length direction, height direction, and width direction are referred to as Figure 1 Here, the length direction (x direction), the height direction (y direction), and the width direction (z direction) are orthogonal to each other.

[0020] The longitudinal direction (x direction) is a direction parallel to the stacking direction.

[0021] like Figure 1 As shown, the stack 10 has a first end face 11 and a second end face 12 opposite to each other in the length direction (x direction), a first main face 13 and a second main face 14 opposite to each other in the height direction (y direction) perpendicular to the length direction, and a first side face 15 and a second side face 16 opposite to each other in the width direction (z direction) perpendicular to the length direction and the height direction.

[0022] Although Figure 1 Although not shown, it is preferred that the laminate 10 have rounded corners and ridges. A corner is a portion where three faces of the laminate intersect, and a ridge is a portion where two faces of the laminate intersect.

[0023] The first external electrode and the second external electrode are external electrodes extending from at least a portion of an end surface of the stacked body to a main surface of the stacked body, for example.

[0024] exist Figure 1 In the illustrated laminated coil component 1 , the first external electrode 21 is arranged to cover a portion of the first end surface 11 of the laminate 10 , and extends from the first end surface 11 to cover a portion of the first main surface 13 .

[0025] The first external electrode 21 covers a region of the first end surface 11 including a ridge portion intersecting with the first main surface 13 .

[0026] In addition, Figure 1 In the embodiment, although the height of the first external electrode 21 covering the portion of the first end surface 11 of the stack 10 is constant, the shape of the first external electrode 21 is not particularly limited as long as it covers a portion of the first end surface 11 of the stack 10. For example, on the first end surface 11 of the stack 10, the first external electrode 21 may be in the shape of a mountain that becomes higher from the end toward the center. In addition, although the length of the first external electrode 21 covering the portion of the first main surface 13 of the stack 10 is constant, the shape of the first external electrode 21 is not particularly limited as long as it covers a portion of the first main surface 13 of the stack 10. For example, on the first main surface 13 of the stack 10, the first external electrode 21 may be in the shape of a mountain that becomes longer from the end toward the center.

[0027] like Figure 1 As shown, the first external electrode 21 may be arranged to further extend from the first end surface 11 and the first main surface 13 and to cover a portion of the first side surface 15 and a portion of the second side surface 16. In this case, it is preferable that the portions of the first external electrode 21 covering both the first side surface 15 and the second side surface 16 are formed to be inclined relative to the ridgeline portion intersecting with the first end surface 11 and the ridgeline portion intersecting with the first main surface 13. Furthermore, the first external electrode 21 does not necessarily need to be arranged to cover a portion of the first side surface 15 and a portion of the second side surface 16.

[0028] exist Figure 1 In the illustrated laminated coil component 1 , the second external electrode 22 is arranged to cover a portion of the second end surface 12 of the laminate 10 , and extends from the second end surface 12 to cover a portion of the first main surface 13 .

[0029] Like the first external electrode 21 , the second external electrode 22 covers a region of the second end surface 12 including a ridge portion intersecting with the first main surface 13 .

[0030] As with the first external electrode 21, the shape of the second external electrode 22 is not particularly limited, as long as it covers a portion of the second end surface 12 of the stack 10. For example, on the second end surface 12 of the stack 10, the second external electrode 22 may have a mountain shape that gradually increases in height from the end toward the center. Furthermore, the shape of the second external electrode 22 is not particularly limited, as long as it covers a portion of the first principal surface 13 of the stack 10. For example, on the first principal surface 13 of the stack 10, the second external electrode 22 may have a mountain shape that gradually increases in height from the end toward the center.

[0031] Similar to the first external electrode 21, the second external electrode 22 may be arranged to further extend from the second end surface 12 and the first main surface 13 and to cover a portion of the first side surface 15 and a portion of the second side surface 16. In this case, it is preferable that the second external electrode 22 covering the portions of the first side surface 15 and the second side surface 16 are both formed to be inclined relative to the ridgeline intersecting with the second end surface 12 and the ridgeline intersecting with the first main surface 13. Furthermore, the second external electrode 22 does not necessarily need to be arranged to cover a portion of the first side surface 15 and a portion of the second side surface 16.

[0032] Since the first external electrode 21 and the second external electrode 22 are arranged as described above, when the laminated coil component 1 is mounted on a substrate, the first principal surface 13 of the laminate 10 serves as a mounting surface.

[0033] In addition, you can also Figure 1 Unlike the embodiment shown, the first external electrode covers the entire first end surface of the laminate and extends from the first end surface to cover a portion of the first main surface, a portion of the second main surface, a portion of the first side surface, and a portion of the second side surface.

[0034] Alternatively, the second external electrode may cover the entire second end surface of the laminate and extend from the second end surface to cover a portion of the first principal surface, a portion of the second principal surface, a portion of the first side surface, and a portion of the second side surface.

[0035] In this case, any one of the first main surface, the second main surface, the first side surface, and the second side surface of the laminate serves as the mounting surface.

[0036] The size of the laminated coil component of the present invention is not particularly limited, but is preferably 0603 size, 0402 size, or 1005 size.

[0037] The insulating layer includes a ferrite phase having a spinel structure and a ZnFe(BO 3 )O type crystal phase.

[0038] When the insulating layer constituting the stacked coil component includes a ferrite phase with a spinel structure, by further including a ZnFe(BO3)O type crystal phase, the linear expansion coefficient of the insulating layer at high temperature increases, which can suppress the generation of cracks in the external electrode during sintering.

[0039] From the viewpoint of effectively suppressing the generation of cracks during sintering of the external electrodes, it is preferable that the linear expansion coefficient of the insulating layer at 700°C is within 9×10 －6 / K or more, more preferably 10×10 －6 / K or above.

[0040] In particular, if the linear expansion coefficient of the insulating layer at 700°C is 10×10 －6 / K or more, it is possible to prevent the generation of cracks in the external electrodes during sintering.

[0041] The upper limit of the linear expansion coefficient of the insulating layer at 700°C is not particularly limited, and can be, for example, 14×10 －6 / K or less, and can also be 13×10 －6 / K or less, and can also be 12.5×10 －6 / K or less.

[0042] From the viewpoint of effectively suppressing the generation of cracks during sintering of the external electrode containing silver, it is preferable that the difference in linear expansion coefficient between the insulating layer and silver at 700°C is within 9.9×10 －6 / K or less, more preferably 8.9×10 －6 / K or less.

[0043] In particular, if the difference in linear expansion coefficient between the insulating layer and silver at 700°C is 8.9×10 －6 / K or less, it is possible to prevent the generation of cracks in the external electrodes during sintering.

[0044] The difference between the linear expansion coefficients of the insulating layer and silver refers to a value obtained by subtracting the linear expansion coefficient of the insulating layer from the linear expansion coefficient of silver.

[0045] The lower limit of the difference in linear expansion coefficient between the insulating layer and silver at 700°C is not particularly limited, and can be, for example, 4.9×10 －6 / K or above, and can also be 5.9×10 －6 / K or above, and can also be 6.4×10 －6 / K or above.

[0046] The spinel-structured ferrite phase is a phase containing a ferrite material having a spinel structure (spinel-type ferrite). The ferrite phase may be a phase composed only of a ferrite material having a spinel structure.

[0047] The ZnFe(BO 3 ) O type crystal phase is a phase containing crystals of ZnFe(BO 3 ) O. This crystal phase may be a phase consisting only of crystals of ZnFe(BO 3 ) O.

[0048] Preferably, the insulating layer further contains a crystalline phase of forsterite.

[0049] By further including a forsterite crystal phase in the insulating layer constituting the laminated coil component, it is possible to prevent the generation of cracks in the external electrodes during sintering.

[0050] The forsterite crystal phase is a phase containing forsterite (2MgO·SiO 2 ) crystals. This crystal phase may also be a phase consisting only of forsterite crystals.

[0051] Preferably, the insulating layer further comprises a crystalline phase of quartz.

[0052] The quartz crystal phase is a phase containing quartz (SiO2) crystals. This quartz crystal phase may also be a phase consisting only of quartz crystals.

[0053] The insulating layer may further include a MgFe2(BO3)O2 type crystal phase.

[0054] The MgFe2(BO3)O2 type crystalline phase is a phase containing crystals of MgFe2(BO3)O2. This crystalline phase may also be a phase consisting only of crystals of MgFe2(BO3)O2.

[0055] The insulating layer may not contain a crystalline phase of forsterite when it contains a crystalline phase of MgFe2(BO3)O2 type, and conversely, it may not contain a crystalline phase of MgFe2(BO3)O2 type when it contains a crystalline phase of forsterite.

[0056] In addition, the above-mentioned spinel structured ferrite phase, ZnFe(BO3)O type crystal phase, forsterite crystal phase, quartz crystal phase, and MgFe2(BO3)O2 type crystal phase can all be identified by X-ray diffraction.

[0057] It is preferred that the ferrite phase is a magnetic phase of a spinel structure containing at least Fe, Ni, Zn, and Cu, and the insulating layer contains a non-magnetic phase containing at least a ZnFe(BO 3 )O type crystal phase and Si.

[0058] As described above, the ferrite phase is preferably a magnetic phase having a spinel structure containing at least Fe, Ni, Zn, and Cu. In this case, the ferrite phase (magnetic phase) may further contain Co, Bi, Sn, Mn, and the like.

[0059] The ferrite material having a spinel structure contained in the ferrite phase (magnetic phase) is preferably a Ni-Cu-Zn ferrite material, and the ferrite phase (magnetic phase) is preferably a Ni-Cu-Zn ferrite material. The inductance of the laminated coil component is improved by using a Ni-Cu-Zn ferrite phase (magnetic phase).

[0060] The Ni—Cu—Zn-based ferrite material may further contain additives such as Co, Bi, Sn, and Mn, and unavoidable impurities.

[0061] The ferrite phase (magnetic phase) may contain Fe, Ni, Zn, and Cu when performing elemental analysis. The magnetic phase may further contain Co, Bi, Sn, Mn, etc. when performing elemental analysis.

[0062] The ferrite phase (magnetic phase) preferably contains Fe in an amount of more than 40 mol% and less than 49.5 mol% as calculated on the basis of Fe2O3, Zn in an amount of more than 2 mol% and less than 35 mol% as calculated on the basis of ZnO, Cu in an amount of more than 6 mol% and less than 13 mol% as calculated on the basis of CuO, and Ni in an amount of more than 10 mol% and less than 45 mol% as calculated on the basis of NiO.

[0063] The non-magnetic phase is a phase containing a non-magnetic material and contains at least a ZnFe(BO3)O type crystal phase and Si. The non-magnetic phase may also be a phase composed only of a non-magnetic material.

[0064] As non-magnetic materials constituting the non-magnetic phase, in addition to ZnFe(BO3)O, dielectric glass materials, forsterite (2MgO·SiO2), zinc silicate [aZnO·SiO2 (a is greater than 1.8 and less than 2.2)], etc. can be listed.

[0065] Preferably, the non-magnetic phase comprises a dielectric glass material.

[0066] By including a dielectric glass material in the non-magnetic phase, the dielectric constant of the insulating layer can be reduced. Due to the reduced dielectric constant of the insulating layer, the losses caused by the LC resonance of the stacked coil component are reduced. Specifically, the decrease in the transmission coefficient S21 caused by the LC resonance can be shifted toward higher frequencies, for example, improving the transmission coefficient S21 in the frequency range up to 60 GHz. Therefore, the stacked coil component of the present invention can have excellent high-frequency characteristics.

[0067] As the dielectric glass material, borosilicate glass is preferably used.

[0068] The borosilicate glass preferably contains Si in a ratio of 70% by weight or more and 85% by weight or less as SiO2, B in a ratio of 10% by weight or more and 25% by weight or less as B2O3, alkali metal A in a ratio of 0.5% by weight or more and 5% by weight or less as Al2O3, and Al in a ratio of 0% by weight or more and 5% by weight or less as Al2O3. Examples of the alkali metal A include K and Na.

[0069] The non-magnetic phase may further contain forsterite (2MgO·SiO 2 ) as a filler, and may further contain quartz (SiO 2 ) or the like as a dielectric glass material and a filler.

[0070] That is, the non-magnetic phase may further include the above-mentioned forsterite crystal phase, quartz crystal phase, and the like.

[0071] The ferrite phase (magnetic phase) and the non-magnetic phase can be distinguished as follows. First, the laminated coil component is polished to expose a cross-section along the lamination direction. Elemental mapping is then performed using scanning transmission electron microscopy-energy dispersive X-ray analysis (STEM-EDX). The two phases are then distinguished by defining the region containing the Fe element (preferably, the region containing Fe, Ni, Zn, and Cu) as the ferrite phase and the region outside the ferrite phase as the non-magnetic phase.

[0072] In addition, the cross section along the stacking direction is described later. Figure 2 The cross section shown.

[0073] The non-magnetic material constituting the non-magnetic phase preferably has a lower dielectric constant than the ferrite material constituting the ferrite phase (magnetic phase).

[0074] The relative dielectric constant of the ferrite material may be, for example, not less than 14.0 and not more than 15.5.

[0075] The dielectric constant of the non-magnetic material is preferably lower than that of the magnetic material, for example, preferably 7.0 or less, more preferably 5.0 or less. The lower limit of the dielectric constant of the non-magnetic material is not particularly limited, but may be 3.5 or more, for example.

[0076] To determine the specific dielectric constant of a ferrite material and the specific dielectric constant of a non-magnetic material, the structural formula of the ferrite material constituting the ferrite phase is determined using the aforementioned elemental mapping, and the structural formula of the non-magnetic material constituting the non-magnetic phase is also determined. Then, the specific dielectric constant of the compound that corresponds to this structural formula is calculated using a known database. This procedure allows the specific dielectric constant of the ferrite material and the specific dielectric constant of the non-magnetic material to be determined separately.

[0077] Alternatively, a dielectric constant measurement sample can be prepared by forming a ferrite material into a predetermined shape, and then forming an electrode from this sample to measure the specific dielectric constant under predetermined conditions. Similarly, a dielectric constant measurement sample can be prepared by forming a non-magnetic material into a predetermined shape, and then measuring the specific dielectric constant of the non-magnetic material.

[0078] The volume ratio of the non-magnetic phase relative to the total volume of the ferrite phase (magnetic phase) and the non-magnetic phase is preferably greater than 50 volume % and less than 90 volume %, more preferably greater than 60 volume % and less than 90 volume %, and further preferably greater than 70 volume % and less than 90 volume %.

[0079] The volume ratio of the non-magnetic phase to the total volume of the ferrite phase (magnetic phase) and the non-magnetic phase is determined as follows: First, the laminate constituting the laminated coil component is ground to the center portion in a direction perpendicular to the stacking direction to expose a cross section along the stacking direction.

[0080] Next, 50μm square areas were extracted at three locations near the center of the exposed cross-section and elemental mapping was performed using scanning transmission electron microscopy (STEM)-energy dispersive X-ray analysis to distinguish the ferrite phase from the non-magnetic phase as described above. The elemental mapping images obtained for each of the three locations were then used to determine the area ratio of the non-magnetic phase relative to the combined area of ​​the ferrite and non-magnetic phases using image analysis software. These area ratio measurements were then averaged and used as the volume ratio of the non-magnetic phase relative to the combined volume of the ferrite and non-magnetic phases.

[0081] Next, an example of a coil built into a laminated body constituting a laminated coil component will be described.

[0082] The coil is formed by electrically connecting a plurality of coil conductors stacked in a stacking direction together with insulating layers.

[0083] Figure 2 is a cross-sectional view schematically showing an example of a laminated coil component according to the present invention. Figure 3 It schematically represents the composition Figure 2 The schematic exploded perspective view of the insulating layer of the laminated coil component shown in FIG. Figure 4 It schematically represents the composition Figure 2 Schematic diagram of an exploded plan view of the insulating layer of the laminated coil component shown.

[0084] Figure 2 The insulating layer, coil conductors, connecting conductors, and the stacking direction of the stacked body are schematically shown, and actual shapes and connections are not strictly shown. For example, the coil conductors are connected via via-hole conductors.

[0085] like Figure 2 As shown, the laminated coil component 1 includes a laminate 10 having a built-in coil 30 , and a first external electrode 21 and a second external electrode 22 electrically connected to the coil 30 . The coil 30 is formed by electrically connecting a plurality of coil conductors 32 laminated together with an insulating layer.

[0086] For example, the laminate 10 includes a region where the coil conductor 32 is arranged and a region where the first connecting conductor 41 or the second connecting conductor 42 is arranged. Figure 2 In FIG, the coil axis A) is parallel to the first main surface 13 .

[0087] like Figure 3 as well as Figure 4 As shown, the laminate 10 includes an insulating layer 31a, an insulating layer 31b, an insulating layer 31c, and an insulating layer 31d. Figure 2 The laminate 10 includes an insulating layer 35a1, an insulating layer 35a2, an insulating layer 35a3, and an insulating layer 35a4, as Figure 2 The laminate 10 includes an insulating layer 35b1, an insulating layer 35b2, an insulating layer 35b3, and an insulating layer 35b4, as Figure 2 Insulating layer 35b.

[0088] The coil 30 includes a coil conductor 32a, a coil conductor 32b, a coil conductor 32c, and a coil conductor 32d. Figure 2 The coil conductor 32 in.

[0089] The coil conductor 32a, the coil conductor 32b, the coil conductor 32c, and the coil conductor 32d are respectively arranged on the main surfaces of the insulating layer 31a, the insulating layer 31b, the insulating layer 31c, and the insulating layer 31d.

[0090] The lengths of the coil conductors 32a, 32b, 32c, and 32d are each equal to the length of ¾ of a turn of the coil 30. In other words, the number of layers of the coil conductors 32 constituting three turns of the coil 30 is 4. In the laminate 10, the coil conductors 32a, 32b, 32c, and 32d are repeatedly laminated as a unit (three turns).

[0091] Coil conductor 32a includes a wire portion 36a and a pad portion 37a disposed at the end of wire portion 36a. Coil conductor 32b includes a wire portion 36b and a pad portion 37b disposed at the end of wire portion 36b. Coil conductor 32c includes a wire portion 36c and a pad portion 37c disposed at the end of wire portion 36c. Coil conductor 32d includes a wire portion 36d and a pad portion 37d disposed at the end of wire portion 36d.

[0092] Via-hole conductors 33a, 33b, 33c, and 33d are respectively arranged in insulating layers 31a, 31b, 31c, and 31d so as to penetrate in the stacking direction.

[0093] The insulating layer 31a with the coil conductor 32a and the through-hole conductor 33a, the insulating layer 31b with the coil conductor 32b and the through-hole conductor 33b, the insulating layer 31c with the coil conductor 32c and the through-hole conductor 33c, and the insulating layer 31d with the coil conductor 32d and the through-hole conductor 33d are considered as a unit ( Figure 3 as well as Figure 4 The portions surrounded by the dotted lines in the figure are repeatedly stacked. Thus, the pad portion 37a of coil conductor 32a, the pad portion 37b of coil conductor 32b, the pad portion 37c of coil conductor 32c, and the pad portion 37d of coil conductor 32d are connected via through-hole conductors 33a, 33b, 33c, and 33d. In other words, the pad portions of coil conductors adjacent to each other in the stacking direction are connected to each other via through-hole conductors.

[0094] As described above, the solenoid-shaped coil 30 built into the laminated body 10 is configured.

[0095] When viewed from above in the stacking direction, the coil 30 composed of the coil conductor 32a, the coil conductor 32b, the coil conductor 32c, and the coil conductor 32d may be circular or polygonal. When viewed from above in the stacking direction, if the coil 30 is polygonal, the diameter of the circle equivalent to the area of ​​the polygon is used as the coil diameter of the coil 30, and the axis passing through the center of gravity of the polygon and extending in the stacking direction is used as the coil axis of the coil 30.

[0096] Through-hole conductors 33p are arranged in each of insulating layers 35a1, 35a2, 35a3, and 35a4 so as to pass through in the stacking direction. Pad portions connected to through-hole conductors 33p may also be arranged on the main surfaces of insulating layers 35a1, 35a2, 35a3, and 35a4.

[0097] The insulating layer 35a1 with the via-hole conductor 33p, the insulating layer 35a2 with the via-hole conductor 33p, the insulating layer 35a3 with the via-hole conductor 33p, and the insulating layer 35a4 with the via-hole conductor 33p are stacked so as to overlap with the insulating layer 31a with the coil conductor 32a and the via-hole conductor 33a. As a result, the via-hole conductors 33p are connected to each other and constitute the first connecting conductor 41, which is exposed at the first end surface 11. As a result, the first external electrode 21 and the coil 30 (coil conductor 32a) are connected to each other via the first connecting conductor 41.

[0098] The first connecting conductor 41 preferably connects the first external electrode 21 and the coil 30 in a linear manner. The first connecting conductor 41 connecting the first external electrode 21 and the coil 30 in a linear manner means that the via-hole conductors 33p constituting the first connecting conductor 41 overlap when viewed from above in the stacking direction, and the via-hole conductors 33p are not necessarily arranged in a strictly linear manner.

[0099] Through-hole conductors 33q are arranged in each of insulating layers 35b1, 35b2, 35b3, and 35b4 so as to pass through the layers in the stacking direction. Pad portions connected to through-hole conductors 33q may also be arranged on the main surfaces of insulating layers 35b1, 35b2, 35b3, and 35b4.

[0100] The insulating layer 35b1 with the via-hole conductor 33q, the insulating layer 35b2 with the via-hole conductor 33q, the insulating layer 35b3 with the via-hole conductor 33q, and the insulating layer 35b4 with the via-hole conductor 33q are stacked so as to overlap with the insulating layer 31d with the coil conductor 32d and the via-hole conductor 33d. Thus, the via-hole conductors 33q are connected to each other to form a second connecting conductor 42, which is exposed at the second end surface 12. As a result, the second external electrode 22 and the coil 30 (coil conductor 32d) are connected to each other via the second connecting conductor 42.

[0101] The second connecting conductor 42 preferably connects the second external electrode 22 and the coil 30 in a linear manner. The second connecting conductor 42 connecting the second external electrode 22 and the coil 30 in a linear manner means that the via-hole conductors 33q constituting the second connecting conductor 42 overlap with each other when viewed from above in the stacking direction, and the via-hole conductors 33q are not necessarily arranged in a strictly linear manner.

[0102] When pad portions are connected to the via-hole conductor 33 p constituting the first coupling conductor 41 and the via-hole conductor 33 q constituting the second coupling conductor 42 , the shapes of the first coupling conductor 41 and the second coupling conductor 42 are shapes excluding the pad portions.

[0103] exist Figure 3 as well as Figure 4, the case where the number of stacking layers of the coil conductor 32 for forming three turns of the coil 30 is four, that is, the case where the repeated shape is a 3 / 4 turn shape, but the number of stacking layers of the coil conductor 32 for forming one turn of the coil is not particularly limited.

[0104] For example, the number of stacked layers of the coil conductor constituting one turn of the coil may be 2, that is, the repetitive shape may be a 1 / 2 turn shape.

[0105] The coil conductors forming the coil preferably overlap when viewed from above in the stacking direction. Furthermore, the coil preferably has a circular shape when viewed from above in the stacking direction. Furthermore, if the coil includes a pad portion, the shape excluding the pad portion (i.e., the shape of the wire portion) is used as the coil shape.

[0106] In addition, when a land portion is connected to a through-hole conductor constituting a connecting conductor, the shape excluding the land portion (ie, the shape of the through-hole conductor) is used as the shape of the connecting conductor.

[0107] also, Figure 3 The coil conductor shown has a circular repetition pattern, but may also have a polygonal shape such as a quadrilateral.

[0108] Furthermore, the repetitive shape of the coil conductor may be a 1 / 2 turn shape instead of a 3 / 4 turn shape.

[0109] The first external electrode and the second external electrode may each have a single-layer structure or a multi-layer structure.

[0110] When the first external electrode and the second external electrode each have a single-layer structure, the constituent material of each external electrode includes, for example, silver, gold, copper, palladium, nickel, aluminum, and alloys containing at least one of these metals, among which silver is preferred.

[0111] When the first and second external electrodes each have a multilayer structure, each external electrode may include, for example, a base electrode layer containing silver, a nickel coating, and a tin coating in this order from the surface side of the laminate. Alternatively, each external electrode may include, for example, a base electrode layer containing silver, a nickel coating, and a gold coating in this order from the surface side of the laminate.

[0112] exist Figure 2 、 Figure 3 as well as Figure 4 In the case of a laminated coil component having the structure shown above, when the size of the laminated coil component is 0603 size, it is preferable to design it as follows in order to further improve the high-frequency characteristics.

[0113] The number of turns of the coil is preferably not less than 33 and not more than 42. If the number of turns is within this range, the total electrostatic capacitance between the coil conductors can be reduced, so the transmission coefficient S21 can be within a good range.

[0114] In addition, the coil length is preferably not less than 0.49 mm and not more than 0.55 mm.

[0115] The width of the coil conductor is preferably not less than 45 μm and not more than 75 μm. Figure 2 The dimensions are shown by the double arrow W.

[0116] The thickness of the coil conductor is preferably not less than 3.5 μm and not more than 6.0 μm. Figure 2 The dimensions are shown by the double arrow T.

[0117] The distance between the coil conductors is preferably greater than 3.0 μm and less than 5.0 μm. Figure 2 The dimensions are shown by the double arrow D.

[0118] The diameter of the land portion of the coil conductor is preferably not less than 30 μm and not more than 50 μm. Figure 4 The dimensions are shown by the double arrow R.

[0119] When the first principal surface of the laminate is the mounting surface, the length of the first external electrode and the length of the second external electrode covering the first principal surface of the laminate are preferably 0.20 mm or less, and preferably 0.10 mm or more.

[0120] The length of the first external electrode and the length of the second external electrode covering the first main surface of the laminate are Figure 2 The dimensions are shown by the double arrow E1.

[0121] In addition, although Figures 2 to 4 For the stacked coil component shown, the stacking direction of the insulating layer and the direction of the coil axis of the coil are parallel to the mounting surface of the stack, i.e., the first main surface, and the length direction, but these directions are not particularly limited. For example, they can also be perpendicular to the mounting surface of the stack, i.e., the first main surface, or they can be parallel to the mounting surface of the stack, i.e., the first main surface, and the width direction.

[0122] For example, the laminated coil component of the present invention is produced by the following method.

[0123] <Ferrite Material (Magnetic Material) Manufacturing Process>

[0124] Fe2O3, ZnO, CuO, and NiO are weighed into a predetermined ratio. Each oxide may also contain unavoidable impurities. Next, these weighed materials are wet-mixed and then crushed to form a slurry. At this time, additives such as Mn3O4, Bi2O3, Co3O4, SiO2, SnO2, etc. may also be added. The obtained slurry is then dried and then temporarily fired. The temporary firing temperature is, for example, above 700°C and below 800°C. The temporary firing time is, for example, above two hours and below five hours. In this way, a powdered ferrite material (magnetic material) is produced.

[0125] Preferably, the ferrite material contains Fe2O3 in an amount of not less than 40 mol% and not more than 49.5 mol%, ZnO in an amount of not less than 2 mol% and not more than 35 mol%, CuO in an amount of not less than 6 mol% and not more than 13 mol%, and NiO in an amount of not less than 10 mol% and not more than 45 mol%.

[0126] <Non-magnetic material manufacturing process>

[0127] Weigh the powder of the non-magnetic material. Prepare glass powder containing an alkali metal such as potassium, boron, silicon, and aluminum in a specified ratio as the dielectric glass material, i.e., borosilicate glass. Also prepare forsterite powder as a filler. Alternatively, prepare quartz powder as both the dielectric glass material and the filler.

[0128] Preferably, the borosilicate glass contains Si in a proportion of 70 weight % or more and 85 weight % or less when converted into SiO2, B in a proportion of 10 weight % or more and 25 weight % or less when converted into B2O3, alkali metal A in a proportion of 0.5 weight % or more and 5 weight % or less when converted into A2O, and Al in a proportion of 0 weight % or more and 5 weight % or less when converted into Al2O3.

[0129] Green Sheet Production Process

[0130] Ferrite material (magnetic material) and non-magnetic material are weighed to a predetermined ratio. These materials are then mixed with an organic binder such as a polyvinyl butyral resin, an organic solvent such as ethanol or toluene, and a plasticizer, and then pulverized to form a slurry. The resulting slurry is then formed into a sheet of a predetermined thickness using a doctor blade method, and then punched into a predetermined shape, such as a rectangle, to form a green sheet.

[0131] The thickness of the green sheet is preferably not less than 20 μm and not more than 30 μm.

[0132] It is preferred to adjust the volume ratio of the ferrite material and the non-magnetic material to a volume ratio of the non-magnetic material relative to the total volume of the ferrite material (magnetic material) and the non-magnetic material to be greater than 50 volume % and less than 90 volume % and mix them. It is more preferred to adjust the volume ratio of the ferrite material and the non-magnetic material to a volume ratio of the above-mentioned non-magnetic material to be greater than 60 volume % and less than 90 volume % and mix them. It is further preferred to adjust the volume ratio of the ferrite material and the non-magnetic material to a volume ratio of the above-mentioned non-magnetic material to be greater than 70 volume % and less than 90 volume % and mix them.

[0133] <Conductor Pattern Formation Process>

[0134] First, through-holes are formed by irradiating a predetermined position of a green sheet with laser light.

[0135] Next, a conductive paste such as silver paste is filled in the through-holes by screen printing or the like and applied to the surface of the green sheet. Thus, a conductor pattern for a through-hole conductor is formed in the through-holes of the green sheet, and a conductor pattern for a coil conductor connected to the conductor pattern for the through-hole conductor is formed on the surface. In this way, a coil sheet is produced in which a conductor pattern for a coil conductor and a conductor pattern for a through-hole conductor are formed on the green sheet. A plurality of coil sheets are produced, and a pattern equivalent to that of a through-hole conductor is formed on each coil sheet. Figure 3 as well as Figure 4 The coil conductor pattern of the coil conductor shown in FIG. Figure 3 as well as Figure 4 The through-hole conductors shown are conductor patterns for through-hole conductors.

[0136] In addition, by using a screen printing method or the like, a conductive paste such as silver paste is filled in the through holes, and a through-hole sheet having a conductor pattern for a through-hole conductor formed on the green sheet is produced separately from the coil sheet. A plurality of through-hole sheets are produced, and each through-hole sheet is formed with a conductive pattern equivalent to Figure 3 as well as Figure 4 The through-hole conductors shown are conductor patterns for through-hole conductors.

[0137] <Laminated block manufacturing process>

[0138] By following the equivalent Figure 3 as well as Figure 4 The coil sheets and the through-hole sheets are stacked in the stacking direction in the order of 100,000 and 100,000 respectively, and then thermocompression-bonded to form a stacked body block.

[0139] <Laminate and coil production process>

[0140] First, the laminated body block is cut into predetermined sizes using a dicing machine or the like to produce individual chips.

[0141] Next, the singulated chips are fired at a temperature of, for example, 900° C. or higher and 920° C. or lower, and for a time of, for example, two hours or higher and four hours or lower.

[0142] By firing the individual chips, the coil sheets and the green sheets of the through-hole sheets become insulating layers. This results in a laminated body composed of multiple insulating layers stacked in the stacking direction, in this case, the longitudinal direction. This laminated body contains a ferrite phase (magnetic phase) and a non-magnetic phase.

[0143] By firing the singulated chips, the coil conductor pattern and the via conductor pattern of the coil sheet become coil conductors and via conductors, respectively. As a result, a coil is formed in which a plurality of coil conductors are stacked in the stacking direction and electrically connected via the via conductors.

[0144] The stacking direction of the insulating layers and the direction of the coil axis of the coil are parallel to the mounting surface of the stack, that is, the first main surface, and here, parallel to the longitudinal direction.

[0145] By firing the singulated chips, the conductor pattern for the through-hole conductors of the through-hole sheet becomes a through-hole conductor. This results in a first connecting conductor and a second connecting conductor, each of which is stacked and electrically connected in the longitudinal direction. The first connecting conductor is exposed from the first end surface of the stacked body. The second connecting conductor is exposed from the second end surface of the stacked body.

[0146] Corners and ridges may be rounded by, for example, barrel polishing the laminate.

[0147] External electrode formation process

[0148] First, a conductive paste containing silver and glass powder is applied to the first and second end faces of the laminate. Next, the resulting coatings are sintered to form a base electrode layer on the surface of the laminate. More specifically, a base electrode layer is formed that extends from the first end face of the laminate to a portion of each of the first principal surface, the first side surface, and the second side surface. Additionally, a base electrode layer is formed that extends from the second end face of the laminate to a portion of each of the first principal surface, the first side surface, and the second side surface. The sintering temperature of each coating is, for example, above 800°C and below 820°C.

[0149] Thereafter, a nickel coating and a tin coating are sequentially formed on the surface of each underlying electrode layer by electrolytic plating or the like.

[0150] In this way, a first external electrode electrically connected to the coil via the first connecting conductor and a second external electrode electrically connected to the coil via the second connecting conductor are formed.

[0151] Through the above, a laminated coil component is manufactured.

[0152] [Example]

[0153] Hereinafter, embodiments of the laminated coil component of the present invention will be described in more detail. However, the present invention is not limited to these embodiments.

[0154] [Examples 1 to 12, and Comparative Examples 1 to 3]

[0155] Laminated bodies for laminated coil components of Examples 1 to 12 and Comparative Examples 1 to 3 were produced by the following method.

[0156] <Ferrite Material (Magnetic Material) Manufacturing Process>

[0157] The main components were weighed to a ratio of 48.0 mol% Fe2O3, 30.0 mol% ZnO, 14.0 mol% NiO, and 8.0 mol% CuO. These components, along with pure water, a dispersant, and PSZ media, were then placed in a ball mill, mixed, and pulverized to create a slurry. The resulting slurry was then dried and then calcined at 800°C for two hours. This produced a powdered ferrite material (magnetic material).

[0158] <Dielectric glass material manufacturing process>

[0159] Prepare borosilicate glass powder containing Si, B, K, and Al in predetermined proportions, and quartz powder as a filler. The borosilicate glass powder and quartz powder are weighed to a weight ratio of 75:25. Next, these weighed materials, pure water, a dispersant, and a PSZ medium are placed in a ball mill, mixed, and then pulverized to create a slurry. The resulting slurry is then dried to produce a powdered dielectric glass material.

[0160] <Forsterite preparation process>

[0161] Forsterite powder is prepared as a filler.

[0162] In addition, both dielectric glass materials and forsterite are non-magnetic materials.

[0163] Green Sheet Production Process

[0164] The ferrite material, dielectric glass material, and forsterite were weighed so that the volume ratios of the ferrite material, dielectric glass material, and forsterite were as shown in Table 1 below. These weighed materials, a polyvinyl butyral resin as an organic binder, and ethanol and toluene as organic solvents were placed in a ball mill, mixed, and then pulverized to form a slurry. The resulting slurry was then formed into a sheet of a predetermined thickness using a doctor blade method, and then punched into a predetermined shape to form a green sheet.

[0165] <Conductor Pattern Formation Process>

[0166] A conductive paste for an internal conductor containing silver powder and an organic vehicle is prepared.

[0167] Through holes are formed at predetermined locations on the green sheet and filled with conductive paste to form through-hole conductors. Thereafter, a coil conductor pattern is printed to obtain a coil sheet.

[0168] Furthermore, through holes are formed by irradiating a predetermined position of the green sheet with a laser beam, and the through holes are filled with a conductive paste to form a through-hole conductor to obtain a through-hole sheet.

[0169] <Laminated block manufacturing process>

[0170] By following the equivalent Figure 3 as well as Figure 4 The coil sheets and the through-hole sheets are stacked in the stacking direction in the order of , and then thermocompression-bonded to form a stacked body block.

[0171] <Laminate and coil production process>

[0172] The stacked body block was cut into individual pieces using a dicing machine to produce individual chips. The individual chips were then fired in a firing furnace at 920° C. for four hours to form a stacked body.

[0173] External electrode formation process

[0174] A conductive paste for external electrodes containing silver powder and glass frit is poured into a coating film forming tank to form a coating film of a predetermined thickness. The locations where the external electrodes of the laminate are to be formed are immersed in the coating film.

[0175] After the impregnation, the base electrode layer of the external electrode is formed by sintering at a temperature of about 800° C. The thickness of the base electrode layer is about 5 μm.

[0176] Next, a nickel coating and a tin coating were sequentially formed on the base electrode layer by electrolytic plating to form external electrodes.

[0177] As described above, laminated coil components of Examples 1 to 12 and Comparative Examples 1 to 3 were manufactured.

[0178] The dimensions of the manufactured laminated coil component were 0.6 mm in the longitudinal direction, 0.3 mm in the height direction, and 0.3 mm in the width direction.

[0179] In addition, Examples 1 to 12 have compositions in which the mixing ratios of the ferrite material, the dielectric glass material, and forsterite are changed, and Comparative Examples 1 to 3 have compositions in which forsterite is not used.

[0180] In addition, the green sheets were stacked and pressure-welded, then cut using a cutter and fired in a firing furnace at 920°C for four hours to produce prism samples with dimensions after firing of approximately 1 mm in width, 5 mm in length, and 1 mm in height.

[0181] X-ray diffraction

[0182] The prepared prism sample was pulverized into powder and subjected to X-ray diffraction evaluation to determine an X-ray diffraction pattern with a 2θ range of 10 to 100°. Cu-Kα1 radiation was used as the X-ray source.

[0183] Analysis of the resulting X-ray diffraction pattern revealed diffraction peaks derived from spinel ferrite, quartz crystals, crystals represented by MgFe(BO)O (hereinafter referred to as crystal A), crystals represented by ZnFe(BO)O (hereinafter referred to as crystal B), and forsterite. The results are shown in Table 1 below.

[0184] In addition, in Table 1, the case where the diffraction peak based on each crystal phase appears is set as 0, and the case where it does not appear is set as ×. Figure 5 The X-ray diffraction pattern of Example 6 is shown.

[0185] Figure 5 The X-ray diffraction pattern of the sample prepared in Example 6 is shown.

[0186] <Measurement of linear expansion coefficient>

[0187] The linear expansion coefficient at 700°C was measured by thermomechanical analysis (TMA) using the prepared prism samples. The results are shown in Table 1 and Figure 6 shown.

[0188] Figure 6 This is a graph showing the linear expansion coefficients at 700° C. of samples prepared in Examples 1 to 12 and Comparative Examples 1 to 3.

[0189] <Evaluation of the presence or absence of cracks>

[0190] The produced laminated coil component was observed using a digital microscope (VHX-6000 manufactured by Keyence Corporation) to evaluate the presence or absence of cracks.

[0191] One hundred components of each type were evaluated. Among the one hundred components, those with zero cracks were marked as 0, those with one to less than ten cracks were marked as △, and those with more than ten cracks were marked as ×. The results are shown in Table 1 below.

[0192]

Table 1

[0193]

[0194] Table 1 shows that when the insulating layer contains forsterite, spinel ferrite crystals, quartz crystals, and crystals B are generated.

[0195] Furthermore, it was found that Crystal A was also generated in the region where the forsterite content was 4.4 to 9.1% by volume, and that forsterite was also present in the region where the forsterite content was 14.3 to 20% by volume.

[0196] In addition, the linear expansion coefficient of the insulating layer at 700°C is 9×10 －6 In Examples 1 to 12 where the value of / K was greater than or equal to , the occurrence of cracks was suppressed.

[0197] In particular, the linear expansion coefficient of the insulating layer at 700°C is 10×10 －6 In Examples 2 to 4, 6 to 8, and 10 to 12 where the temperature was greater than / K, no cracks were observed.

[0198] This is because the linear expansion coefficient of the insulating layer at 700°C is similar to the linear expansion coefficient of silver at 700°C (18.9×10 －6 The difference between the linear expansion coefficients is reduced, and the stress generated due to the difference between the linear expansion coefficients is reduced when the temperature is lowered during sintering of the base electrode.

[0199] Description of Reference Numerals

[0200] 1…Laminated coil component, 10…Laminated body, 11…First end surface, 12…Second end surface, 13…First principal surface, 14…Second principal surface, 15…First side surface, 16…Second side surface, 21…First external electrode, 22…Second external electrode, 30…Coil, 31, 31a, 31b, 31c, 31d, 35a, 35a1, 35a2, 35a3, 35a4, 35b , 35b1, 35b2, 35b3, 35b4…insulating layer, 32, 32a, 32b, 32c, 32d…coil conductor, 33a, 33b, 33c, 33d, 33p, 33q…through-hole conductor, 36a, 36b, 36c, 36d…line portion, 37a, 37b, 37c, 37d…pad portion, 41…first connecting conductor, 42…second connecting conductor.

Claims

1. A laminated coil component, characterized in that: The invention comprises a laminated body and an external electrode, wherein the laminated body is formed by stacking a plurality of insulating layers in a stacking direction and a coil is provided inside the laminated body, and the external electrode is provided on a surface of the laminated body and is electrically connected to the coil. The insulating layer includes a ferrite phase having a spinel structure and a ZnFe(BO 3 )O type crystal phase.

2. The laminated coil component according to claim 1, wherein The linear expansion coefficient of the above-mentioned insulating layer at 700°C is 9×10 －6 / K or above.

3. The laminated coil component according to claim 2, wherein: The linear expansion coefficient of the above-mentioned insulating layer at 700°C is 10×10 －6 / K or above.

4. The laminated coil component according to any one of claims 1 to 3, wherein: The insulating layer further includes a forsterite crystal phase.

5. The laminated coil component according to any one of claims 1 to 3, wherein: The insulating layer further includes a quartz crystal phase.

6. The laminated coil component according to any one of claims 1 to 3, wherein: The ferrite phase is a magnetic phase with a spinel structure containing at least Fe, Ni, Zn and Cu. The insulating layer includes at least the ZnFe(BO 3 )O type crystalline phase and a non-magnetic phase of Si.

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