Laminated coil components

Abstract

The present invention provides a laminated coil component with excellent productivity that can achieve further relaxation of internal stress while ensuring the strength of the laminate. The laminated coil component is a laminated coil component (1) having a laminate (10) in which a coil (30) is provided inside an insulator portion (40) formed by stacking a plurality of insulating layers, wherein a plurality of coil conductors (31) are electrically connected via a conducting conductor (33). A first coil conductor (31b) and a second coil conductor (31c) adjacent in a stacking direction and electrically connected in series via a first conducting conductor (33b) each have a first main surface (32a) facing the opposite side of the stacking direction and having a gap (50) between them and the insulator portion (40). The second coil conductor (31c) has a second main surface (32b) facing the stacking direction and having a gap (60) between them and the insulator portion (40), wherein the gap (60) is partially present at a position opposite to the first conducting conductor (33b).

Description

Technical Field

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

[0002] As a laminated coil component, for example, Patent Document 1 discloses a laminated coil component in which stress relaxation spaces are formed on one surface and / or the other surface in the lamination direction of each of a plurality of coil conductors.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-59749

[0004] However, in the laminated coil component described in Patent Document 1, when the stress relaxation space is provided only on one surface or the other surface in the lamination direction of the coil conductor, the stress relaxation effect is insufficient.

[0005] On the other hand, the stress relief spaces are formed along the entire portion of the coil conductor, excluding the ends. Therefore, if stress relief spaces are provided on both the surface of one side and the surface of the other side in the stacking direction of the coil conductor, there is a concern that the strength of the laminated structure may be insufficient. Furthermore, this scenario involves a large number of steps (screen-printing the ZrO2 paste) to form the stress relief spaces, leading to reduced productivity. 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 with excellent productivity that can further alleviate internal stress while ensuring the strength of the laminate.

[0007] The laminated coil component of the present invention comprises: a laminated body, in which a coil is arranged inside an insulating body portion formed by stacking a plurality of insulating layers; and an external electrode, which is arranged on the outer surface of the laminated body and electrically connected to the coil. The laminated coil component is characterized in that the coil is formed by electrically connecting a plurality of coil conductors stacked together with the plurality of insulating layers via a conducting conductor, the plurality of coil conductors respectively having a first main surface facing the opposite side of the stacking direction and a second main surface facing the stacking direction, the plurality of coil conductors including a first coil conductor and a second coil conductor adjacent to each other in the stacking direction, and the plurality of coil conductors respectively having a first main surface facing the opposite side of the stacking direction and a second main surface facing the stacking direction, The first coil conductor and the second coil conductor are electrically connected to each other in series via a first conductive conductor, and the first coil conductor, the first conductive conductor and the second coil conductor are arranged in sequence in the stacking direction. The first coil conductor has a first main surface with a gap between it and the insulator portion, and the second coil conductor has a first main surface with a gap between it and the insulator portion, and a second main surface with a gap between it and the insulator portion. The gap between the second main surface of the second coil conductor and the insulator portion is locally located at a position opposite to the first conductive conductor.

[0008] According to the present invention, it is possible to provide a laminated coil component having excellent productivity, which can further alleviate internal stress while ensuring the strength of the laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view schematically showing an example of the laminated coil component according to the first embodiment.

[0010] Figure 2 This is a perspective view schematically showing an example of a laminated body constituting the laminated coil component according to the first embodiment.

[0011] Figure 3 It is an LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the first embodiment.

[0012] Figure 4 LT is a cross-sectional view schematically showing an example of the first coil conductor and the second coil conductor of the laminated coil component according to the first embodiment.

[0013] Figure 5 It is a plan view schematically showing an example of a via conductor portion of the laminated coil component according to the first embodiment.

[0014] Figure 6 This is another LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the first embodiment.

[0015] Figure 7This is a plan view schematically showing an example of a method for producing a laminated body using the printed sheet lamination method according to the first embodiment.

[0016] Figure 8 This is a plan view schematically showing an example of a method for producing a laminated body using the printed sheet lamination method according to the first embodiment.

[0017] Figure 9 This is a plan view schematically showing an example of a method for producing a laminated body using the printed sheet lamination method according to the first embodiment.

[0018] Figure 10 This is a plan view schematically showing an example of a method for producing a laminated body using the printed sheet lamination method according to the first embodiment.

[0019] Figure 11 This is a cross-sectional view schematically showing an example of the layer structure of the coil sheet after printing of the ceramic paste.

[0020] Figure 12 It is an LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the second embodiment.

[0021] Figure 13 LT is a cross-sectional view schematically showing an example of a first coil conductor and a second coil conductor of the laminated coil component according to the second embodiment.

[0022] Figure 14 It is a plan view schematically showing an example of a via conductor portion of the laminated coil component according to the second embodiment.

[0023] Figure 15 It is an LT cross-sectional view schematically showing another example of the first coil conductor and the second coil conductor of the laminated coil component according to the second embodiment.

[0024] Figure 16 It is a plan view schematically showing another example of the through-conductor portion of the laminated coil component according to the second embodiment.

[0025] Figure 17 It is an LT cross-sectional view schematically showing another example of the first coil conductor and the second coil conductor of the laminated coil component according to the second embodiment.

[0026] Figure 18 It is a plan view schematically showing another example of the through-conductor portion of the laminated coil component according to the second embodiment.

[0027] Description of Reference Numerals

[0028] 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…Coil conductor, 31b…First coil conductor, 31c…Second coil conductor, 32a…First principal surface of coil conductor, 32b…Second principal surface of coil conductor, 33, 33a, 33b, 33c, 83, 83b, 83c…Through conductor, 33b…First through conductor, 35…Through conductor 1, 2, 3, 4, 5, 6, 7, 8, 9…lead-out conductor connected to the outer electrode, 36…lead-out conductor connected to the second outer electrode, 37…slit, 38a, 38b, 38c, 38d…conductor paste layer, 39a, 39b, 39c…conducting hole, 40…insulator portion, 41a, 41b, 41c, 41d…insulator sheet, 42a, 42b, 42c, 42d…insulating layer, 50, 60, 61, 62…gaps, 70a, 70b, 70c, 70d…resin paste layer, 71a, 71b, 71c, 71d…coil sheet, 81…parallel-connected coil (coil conductor), 83c…second conducting conductor, 83b…third conducting conductor. DETAILED DESCRIPTION

[0029] Hereinafter, the laminated coil component of the present invention will be described.

[0030] However, the present invention is not limited to the following embodiments, and can be appropriately modified and applied within the scope of the present invention. In addition, a configuration in which two or more of the preferred configurations described below are combined also constitutes the present invention.

[0031] [First embodiment]

[0032] Figure 1 It is a perspective view schematically showing an example of the laminated coil component according to the first embodiment.

[0033] Figure 2 : is a perspective view schematically showing an example of a laminated body constituting the laminated coil component of the first embodiment. Figure 2 In order to clarify the structure of the coil of the laminated coil component, the inside is schematically shown through.

[0034] Figure 1 as well as Figure 2The illustrated laminated coil component 1 includes a laminate 10, and a first external electrode 21 and a second external electrode 22 disposed on the outer surfaces of the laminate 10. The laminate 10 is a roughly rectangular parallelepiped with six sides. A coil 30 is disposed within an insulator portion 40 formed by stacking multiple insulating layers of ceramic. The structure of the laminate 10 will be described later. The first external electrode 21 and the second external electrode 22 are each electrically connected to the coil 30.

[0035] In the laminated coil component and laminate described in this specification, the direction in which the first external electrode and the second external electrode face each other is defined as the longitudinal direction, the direction perpendicular to the longitudinal direction is defined as the height direction, and the direction perpendicular to the longitudinal direction and the height direction is defined as the width direction.

[0036] exist Figure 1 as well as Figure 2 The longitudinal direction, width direction, and height direction of the laminated coil component and the laminated body are indicated by arrows L, W, and T, respectively.

[0037] The longitudinal direction (L direction), the width direction (W direction), and the height direction (T direction) are orthogonal to each other.

[0038] The mounting surface of the laminated coil component 1 is a surface (LW surface) parallel to the longitudinal direction and the width direction.

[0039] Figure 1 as well as Figure 2 The stacked body 10 shown has a first end face 11 and a second end face 12 opposite to each other in the longitudinal direction, a first main face 13 and a second main face 14 opposite to each other in the height direction perpendicular to the longitudinal direction, and a first side face 15 and a second side face 16 opposite to each other in the width direction perpendicular to the longitudinal direction and the height direction.

[0040] In addition, if Figure 1 as well as Figure 2 As shown, it is preferable that the corners and ridges of the laminate 10 are rounded. A corner is a portion where three surfaces of the laminate intersect, and a ridge is a portion where two surfaces of the laminate intersect.

[0041] like Figure 1 As shown, the first external electrode 21 is arranged to cover the first end surface 11 of the stacked body 10 and extends from the first end surface 11 to cover a portion of the first main surface 13, a portion of the second main surface 14, a portion of the first side surface 15, and a portion of the second side surface 16. Figure 1 As shown, the second external electrode 22 is arranged to cover 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 , a portion of the second main surface 14 , a portion of the first side surface 15 , and a portion of the second side surface 16 .

[0042] The first main surface 13 serves as a mounting surface.

[0043] The coil 30 is formed by electrically connecting the plurality of coil conductors 31 stacked together with the plurality of insulating layers. The plurality of insulating layers are integrated during firing of the laminate 10 in the manufacturing process to form the insulating body portion 40 .

[0044] The direction in which the plurality of insulating layers and the plurality of coil conductors 31 are stacked, that is, the stacking direction of the laminate 10 is along the height direction (T direction). In addition, the coil axis of the coil 30 is along the height direction (T direction).

[0045] In this specification, “upward” refers to a direction toward the stacking direction, and “downward” refers to a direction toward the opposite direction to the stacking direction.

[0046] Each coil conductor 31 constituting the coil 30 is formed into a ring-shaped (C-shaped) conductor with a gap 37 partially left at one location. The plurality of coil conductors 31 are stacked so that the positions of the respective gaps 37 are offset in the winding direction of the coil 30 and overlap one another. Each coil conductor 31 typically has a greater line width than thickness.

[0047] The coil 30 is formed by electrically connecting a plurality of coil conductors 31 in series via the via conductors 33 .

[0048] More specifically, a via conductor 33 is provided between two coil conductors 31 adjacent to each other in the stacking direction, and each via conductor 33 electrically connects one end of the coil conductor 31 below it to the other end of the coil conductor 31 above it.

[0049] In addition, one end and the other end of the coil conductor 31 respectively refer to one end portion and the other end portion in the winding direction of the coil 30 .

[0050] Each via conductor 33 is a columnar conductor extending in the stacking direction. The side surface of each via conductor 33 may be as described below. Figure 3 As shown, it is an inverted cone, but it can also be a right cone or vertical.

[0051] The coil conductor 31 and the first external electrode 21 are electrically connected at the first end surface 11 , and the coil conductor 31 and the second external electrode 22 are electrically connected at the second end surface 12 .

[0052] The conductor leading the coil 30 to the first end surface 11 is the lead conductor 35 , and the conductor leading the coil 30 to the second end surface 12 is the lead conductor 36 .

[0053] In the laminated coil component 1 , the relationship between the length L, which is a dimension in the longitudinal direction, and the width W, which is a dimension in the width direction of the laminate 10 , is L / W>1.

[0054] That is, the length dimension of the laminated body 10 is larger than its width dimension.

[0055] The size of the laminated coil component 1 is not particularly limited, but is preferably 0402 size, 0603 size, 1005 size, or 1608 size.

[0056] Figure 3 It is an LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the first embodiment. Figure 3 is an LT cross-sectional view of a formation portion of a via conductor, Figure 1 Cross-sectional view on line A-A.

[0057] exist Figure 3 The diagram shows coil conductors 31 (31a, 31b, 31c, 31d) constituting the coil 30 and via conductors 33 (33a, 33b, 33c) connecting adjacent coil conductors 31. The coil conductors 31a, 31b, 31c, 31d each represent one turn of the coil conductor 30.

[0058] The maximum thickness of each coil conductor 31 in the stacking direction is preferably 5 μm or more and 25 μm or less, and more preferably 10 μm or more and 20 μm or less.

[0059] The dimension of each via conductor 33 in the stacking direction (the thickness of the insulator portion 40 between two coil conductors 31 adjacent in the stacking direction) is preferably 5 μm or more and 30 μm or less, more preferably 10 μm or more and 25 μm or less.

[0060] Each coil conductor 31 has a first main surface 32a facing the opposite side of the stacking direction, ie, facing downward, and a second main surface 32b facing the stacking direction, ie, facing upward. The first main surface 32a is the main surface on the mounting surface side.

[0061] The first principal surface 32 a and the second principal surface 32 b of each coil conductor 31 are parallel to the first principal surface 13 and the second principal surface 14 of the laminate 10 .

[0062] In addition, Figure 3 The structure shown has a gap 50 between the first main surface 32a of each coil conductor 31 and the insulator portion 40. Providing the gap 50 reduces contact between the insulator portion 40 and each coil conductor 31, thereby alleviating internal stress in the laminate 10.

[0063] A gap 50 is formed in the same pattern as that of the coil conductor 31 at a position slightly inward from the end of the coil conductor 31 .

[0064] The maximum thickness of the void 50 in the stacking direction is preferably 2 μm or more and 15 μm or less, and more preferably 4 μm or more and 6 μm or less.

[0065] And, in Figure 3 The structure shown has a gap 60 between the second main surface 32 b of each coil conductor 31 and the insulator portion 40 (however, only at a position facing the via conductor 33 ).

[0066] Figure 4 LT is a cross-sectional view schematically showing an example of the first coil conductor and the second coil conductor of the laminated coil component according to the first embodiment. Figure 4 LT is a cross-sectional view of the formation portion of the via conductor. Figure 4 A cross-sectional view schematically showing the vicinity of the first via conductor is also shown in an enlarged manner.

[0067] exist Figure 4 , coil conductors 31b and 31c are shown as an example of the first coil conductor and the second coil conductor of the present invention, respectively, and the conducting conductor 33b is shown as an example of the first conducting conductor of the present invention, but the same applies to the other two coil conductors 31 adjacent to each other in the stacking direction and the other conducting conductors 33 sandwiched therebetween.

[0068] like Figure 4 As shown, the first coil conductor 31b and the second coil conductor 31c are adjacent to each other in the stacking direction and are electrically connected in series via the first via conductor 33b. The first coil conductor 31b, the first via conductor 33b and the second coil conductor 31c are arranged in this order in the stacking direction.

[0069] Therefore, the second principal surface 32 b of the first coil conductor 31 b and the first principal surface 32 a of the second coil conductor 31 c are electrically connected via the first via conductor 33 b .

[0070] As described above, the gap 50 exists between the first principal surface 32 a of the first coil conductor 31 b and the insulator portion 40 . Similarly, the gap 50 exists between the first principal surface 32 a of the second coil conductor 31 c and the insulator portion 40 .

[0071] Furthermore, the second coil conductor 31 c has a second main surface 32 b with a gap 60 existing between the second coil conductor 31 c and the insulator portion 40 .

[0072] Providing the gap 60 further reduces the contact between the insulator portion 40 and each coil conductor 31 , and thus it is possible to further alleviate the internal stress of the laminate 10 .

[0073] However, if the gap 60 is provided over a wide range like the gap 50 , the strength of the laminate 10 may become insufficient. However, the gap 60 exists locally at a position facing the first via conductor 33 b .

[0074] Therefore, it is possible to further relax the internal stress while ensuring the required strength of the laminate 10 .

[0075] Furthermore, as will be described later, the gap 60 locally existing at a position facing the first via conductor 33 b can be formed without adding a step for providing the gap 60 , so the laminated coil component 1 can be manufactured with good productivity.

[0076] like Figure 4 As shown in the enlarged view, the ratio of the width W1 of the first conducting conductor 33b in a direction perpendicular to the stacking direction (for example, the longitudinal direction (L direction)) to the width W2 of the gap 60 in that direction (the same direction as the direction in which the width W1 is measured, for example, the longitudinal direction (L direction)) is preferably greater than 0.5 and less than 1.0, and more preferably greater than 0.7 and less than 1.0.

[0077] In addition, when the width W1 of the first via conductor 33 b in the stacking direction is not constant, the width W1 is the maximum width.

[0078] The maximum thickness of the air gap 60 in the lamination direction on the second main surface 32b of the second coil conductor 31c is preferably 1 μm or more and 15 μm or less, and more preferably 5 μm or more and 10 μm or less.

[0079] Figure 5 It is a plan view schematically showing an example of a via conductor portion of the laminated coil component according to the first embodiment.

[0080] like Figure 5 As shown in FIG. 1 , the gap 60 may be included in the arrangement region of the first via conductor 33 b when viewed in plan from the stacking direction.

[0081] The ratio of the area of ​​the gap 60 to the area of ​​the first via conductor 33 b is preferably 25% or more and 100% or less, and more preferably 49% or more and 100% or less, when viewed in plan from the stacking direction.

[0082] Preferred planar shapes (shape when viewed from the stacking direction) of the first via conductor 33b include, for example, an n-gon (n is an integer greater than or equal to 3, such as 3 to 8, preferably 4 to 6), a circle, an ellipse, an oval, or other curved shapes.

[0083] When viewed in plan from the stacking direction, the gap 60 may have substantially the same shape as the first via conductor 33 b .

[0084] The porosity ratio of coil 30 is preferably 5% or more and 15% or less, and more preferably 6% or more and 12% or less. By increasing the porosity ratio compared to conventional methods, gaps 50 and 60 can be more reliably formed. This allows the use of a high-shrinkage conductor paste to form coil 30 with a larger porosity ratio.

[0085] The ratio of the width W2 of the gap 60 to the width W1 of the first via conductor 33 b and the void area ratio of the coil 30 can be measured by the following method.

[0086] First, the sample is placed vertically and fixed with resin so that the LT surface (side surface) is exposed.

[0087] Next, the sample was ground in the W direction using a grinder to a depth at which the via conductor (conductive junction) was exposed.

[0088] Next, the void area ratio was calculated according to the following (1), and the width ratio was calculated according to the following (2).

[0089] (1) The exposed cross-section of the coil conductor was subjected to focused ion beam processing (FIB processing) to obtain a cross-section for SEM observation. An SEM photograph (50 μm × 50 μm area) was taken approximately in the center of the via conductor. The resulting SEM photograph was analyzed using image analysis software to determine the coil's porosity area ratio. The FIB processing was performed using an SMI3050R FIB processing device manufactured by SII Nanotech.

[0090] (2) A SEM photograph of the via conductor is taken, and the dimensions of the width of the first via conductor and the width of the gap are determined from the photograph, and their ratio is determined.

[0091] Figure 6 This is another LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the first embodiment. Figure 6 is a LT cross-sectional view of the lead conductor forming portion, Figure 1 Cross-sectional view on line BB.

[0092] exist Figure 6 The thickness of the lead conductor 35 leading the coil 30 to the first end surface 11 and the thickness of the lead conductor 36 leading the coil 30 to the second end surface 12 are larger than the thickness of the coil conductor 31 .

[0093] This can improve the sealing performance of the laminated coil component 1 .

[0094] Next, an example of a method for manufacturing the laminated coil component according to the present embodiment, particularly a laminated body, will be described.

[0095] Hereinafter, a method for producing a laminated body by a printed sheet lamination method, which is a method of combining printing and lamination of sheets, will be described.

[0096] In the printed sheet lamination method, a plurality of coil sheets having a conductor paste and a ceramic paste printed on an insulating sheet are stacked to form a coil extending in the stacking direction of the stacked body.

[0097] This method is different from the printing lamination method in which a conductor paste and a ceramic paste are simply printed and laminated to form a coil conductor extending in the lamination direction of the laminate.

[0098] This method is also different from the method of forming a sheet having via conductors provided therein by laser drilling holes in the sheet and filling the holes with a conductor paste, and then stacking a plurality of such sheets.

[0099] If the printed sheet lamination method and the printed lamination method are used, the thickness of the internal conductor can be increased. However, if the thickness of the internal conductor is larger, the volume of the internal conductor is also larger, so the shrinkage during firing is larger. As described above, the gap 60 can be more reliably formed at the position opposite to the conducting conductor 33.

[0100] On the other hand, in the printed lamination method, each layer of the laminate is printed to produce it, so drying takes time, and productivity is lower than that of the printed sheet lamination method.

[0101] As described above, the present invention is particularly suitable when a laminated coil component is produced by a printed sheet lamination method.

[0102] Figures 7 to 10 This is a plan view schematically showing an example of a method for producing a laminated body using the printed sheet lamination method according to the first embodiment.

[0103] exist Figures 7 to 10 The layer structure of each coil sheet constituting a laminated body produced by the printed sheet lamination method is shown.

[0104] In the printed sheet lamination method, the insulating sheet shown at the top of each figure is used as a base, and the conductor paste and the ceramic paste are printed in sequence to form the state shown in the lower direction of the figure.

[0105] The insulator sheet and the ceramic paste are materials that become the insulator portion by firing.

[0106] Figures 7 to 10 The layers shown show the top surface state after printing, not the layers made separately. Figures 7 to 10 The layers shown are stacked.

[0107] Figure 11 This is a cross-sectional view schematically showing an example of the layer structure of the coil sheet after printing of the ceramic paste.

[0108] First, ceramic paste, insulating sheet (green sheet), conductor paste, and resin paste are prepared as materials.

[0109] Ferrite paste is preferably used as the ceramic paste.

[0110] The ferrite paste preferably contains 40 mol% to 49.5 mol% Fe (calculated as Fe2O3), 5 mol% to 35 mol% Zn (calculated as ZnO), 4 mol% to 12 mol% Cu (calculated as CuO), and 8 mol% to 42 mol% Ni (calculated as NiO). These materials may contain trace amounts of additives (including unavoidable impurities) such as Bi, Sn, Mn, and Co.

[0111] As a method for producing the ferrite paste, for example, the following method can be cited.

[0112] Fe2O3, ZnO, CuO, NiO, and additives as needed are weighed into a specified composition and placed in a ball mill together with pure water, a dispersant, and a PSZ medium for wet mixing and crushing. The mixture is then discharged and evaporated to dryness, and then pre-calcined at a temperature of not less than 700°C and not more than 800°C for not less than two hours and not more than three hours to obtain a pre-calcined powder.

[0113] Ferrite paste is prepared by adding a predetermined amount of solvent (ketone solvent, etc.), resin (polyvinyl acetal, etc.), and plasticizer (alkyd plasticizer, etc.) to the pre-calcined powder, mixing with a planetary mixer, and then further dispersing with a three-roll mill.

[0114] Then, an insulator sheet is produced from the obtained ceramic paste.

[0115] Specifically, the pre-calcined powder (ferrite material) obtained along with the PSZ dielectric, an organic binder such as a polyvinyl butyral resin, and an organic solvent such as ethanol or toluene are placed in a ball mill and wet-mixed and pulverized to form a slurry. The resulting slurry is then formed into a sheet of a specified thickness using a doctor blade method, and then punched into a specified shape to form an insulator sheet.

[0116] The insulator sheet is an example of an insulating layer of the laminated coil component of the present invention.

[0117] The thickness of the insulating sheet is preferably not less than 10 μm and not more than 30 μm.

[0118] The shrinkage rate of the insulating sheet during firing is preferably 5% or more and 25% or less, more preferably 10% or more and 20% or less.

[0119] As will be described later, the ceramic paste is also used to form an insulating layer in a region where the conductive paste layer is not formed.

[0120] Therefore, the shrinkage rate of the insulating layer during firing is substantially the same as the shrinkage rate of the insulating sheet during firing.

[0121] As the conductor paste, a paste containing silver as a conductive material is preferably used.

[0122] As a method for producing the conductive paste, for example, the following method can be cited.

[0123] Silver powder is prepared, and predetermined amounts of a solvent (such as eugenol), a resin (such as ethyl cellulose), and a dispersant are added thereto. The mixture is mixed with a planetary mixer and then dispersed with a three-roll mill to prepare a conductor paste.

[0124] In the preparation of the above-mentioned conductor paste, the volume concentration of the conductive material relative to the total volume of the conductive material (typically silver powder) and the resin component in the conductor paste, that is, the PVC (pigment volume concentration), is adjusted so that the shrinkage rate of the conductor paste layer during firing is greater than the shrinkage rate of the insulator sheet during firing.

[0125] As a result, the conductive bonding portion can be further shrunk compared to the ceramic during firing, and the void 60 can be selectively formed in the conductive bonding portion.

[0126] Here, the conductive coupling portion refers to a conductor portion composed of a conductive conductor and a coil conductor portion coupled (joined) to the conductive conductor.

[0127] The shrinkage rate of the conductor paste layer during firing is preferably 20% or more and 40% or less, more preferably 25% or more and 35% or less.

[0128] The difference between the shrinkage rate of the conductor paste layer during firing and the shrinkage rate of the insulator sheet during firing is preferably 5% or more and 30% or less, more preferably 15% or more and 20% or less.

[0129] Likewise, the shrinkage rate of the conductor paste layer during firing is greater than the shrinkage rate of the insulating layer formed in the region where the conductor paste layer is not formed.

[0130] Thus, the gap 60 can be formed more effectively on the conductive joint portion.

[0131] Here, for example, the shrinkage rate can be determined by coating a conductive paste or ceramic paste on a polyethylene terephthalate (PET) film, drying it, and then cutting it into pieces of approximately 5 mm x 5 mm. The shrinkage rate can then be determined by measuring the change in sample size using a thermomechanical analyzer (TMA) under the same heating conditions as those used for firing.

[0132] The resin paste is a paste for forming a resin paste layer between the insulator sheet and the conductor paste layer. The void 50 is formed by burning the resin paste layer after firing.

[0133] As a method for preparing the resin paste, for example, the following method can be cited.

[0134] The resin paste is prepared by adding a resin (acrylic resin, etc.) that burns out during firing to a solvent (isophorone, etc.).

[0135] In the drawings, printing and lamination are performed from top to bottom, and therefore the description will be given in this order.

[0136] First, if Figure 7 As shown at the top, an insulator sheet 41a is prepared.

[0137] Next, a resin paste is printed on the insulator sheet 41a to form a resin paste layer 70a as shown in FIG. Figure 7 The second pattern shown above.

[0138] The pattern of the resin paste layer 70a is preferably substantially the same as the pattern of the conductor paste layer 38a for the coil conductor 31 formed later, and the line width of the resin paste layer 70a is preferably slightly smaller than the line width of the conductor paste layer 38a for the coil conductor 31.

[0139] Next, the conductor paste is printed to form the conductor paste layer 36a which will become the lower layer portion of the lead conductor 36 as shown in FIG. Figure 7 The pattern shown above is the third one.

[0140] Next, the conductor paste is printed so as to overlap the resin paste layer 70a and the conductor paste layer 36a, and the conductor paste layer 38a which will become the upper layer of the coil conductor 31 (31a) and the lead conductor 36 is formed as shown in FIG. Figure 7 The pattern shown in the fourth one above.

[0141] Through this process, the thickness of the lead conductor 36 can be increased (see Figure 6 By increasing the thickness of the lead conductor 36 , the sealing property is improved, and it is possible to suppress the occurrence of problems such as the plating solution intruding from the interface between the insulator portion 40 and the lead conductor 36 .

[0142] The conductor paste is formed so as to cover the resin paste layer 70 a .

[0143] Next, insulating layer 42a is formed by printing ceramic paste in the region where conductive paste layer 38a is not formed, thereby forming coil sheet 71a in which insulator sheet 41a, resin paste layer 70a, conductive paste layer 38a, and insulating layer 42a are sequentially stacked.

[0144] The thickness of the insulating layer 42a is approximately the same as that of the conductive paste layer 38a. Furthermore, the insulating layer 42a is printed so that a portion overlaps the end of the conductive paste layer 38a. This printed layer forms the insulating portion 40 surrounding the coil conductor 31 (31a).

[0145] Figure 7 The fifth pattern shown above shows the upper surface after the insulating layer 42a is formed.

[0146] Next, if Figure 8 As shown in the uppermost portion of the figure, an insulator sheet 41b having a via hole 39a formed therein is prepared. The via hole 39a is formed by laser irradiation at a position of the insulator sheet that is in contact with the conductor paste layer 38a formed on the coil sheet 71a.

[0147] Next, a resin paste is printed on the insulator sheet 41b to form a resin paste layer 70b. Figure 8 The second pattern shown above.

[0148] The pattern of the resin paste layer 70b is preferably substantially the same as the pattern of the conductor paste layer 38b for the coil conductor 31 formed later, and the line width of the resin paste layer 70b is preferably slightly smaller than the line width of the conductor paste layer 38b for the coil conductor 31.

[0149] In addition, the resin paste layer 70 b is formed so as not to cover the via hole 39 a .

[0150] Next, the conductor paste is printed so as to overlap the resin paste layer 70b and the via hole 39a, and the conductor paste layer 38b which will become the coil conductor 31 (31b) is formed. Figure 8 The pattern shown above is the third one.

[0151] The via hole 39a is filled with a conductor paste, and the coil conductor 31 (31b) is electrically connected to the coil conductor 31 (31a) in the lower layer via the via conductor.

[0152] The conductor paste is formed so as to cover the resin paste layer 70b.

[0153] Next, insulating layer 42b is formed by printing ceramic paste in the region where conductive paste layer 38b is not formed, thereby forming coil sheet 71b in which insulator sheet 41b, resin paste layer 70b, conductive paste layer 38b, and insulating layer 42b are sequentially stacked.

[0154] like Figure 11 As shown, the thickness of the insulating layer 42b is made approximately the same as that of the conductive paste layer 38b. Furthermore, the insulating layer 42b is printed so that a portion overlaps the end of the conductive paste layer 38b. This printed layer forms the insulating portion 40 surrounding the coil conductor 31 (31b).

[0155] Figure 8 The fourth pattern shown above shows the upper surface after the insulating layer 42b is formed.

[0156] Likewise, if Figure 9 As shown, a coil sheet 71c is formed by sequentially stacking an insulator sheet 41c having a via hole 39b formed therein, a resin paste layer 70c, a conductor paste layer 38c, and an insulating layer 42c, and as shown in FIG. Figure 10 As shown, coil sheet 71d is formed by sequentially stacking insulating sheet 41d having via holes 39c formed therein, resin paste layer 70d, conductor paste layer 35a forming the lower layer of lead conductor 35, conductor paste layer 38d, and insulating layer 42d.

[0157] Then, a plurality of the obtained coil sheets are stacked to produce an unfired laminate.

[0158] Specifically, coil sheets 71a, 71b, 71c, and 71d are stacked in a predetermined order, and a predetermined number of insulator sheets (unprinted sheets) are stacked on top of each other. The stacked sheets are then subjected to a WIP (isotropic hot pressing) process at a temperature between 70°C and 90°C and a pressure between 60 MPa and 100 MPa. This results in a collection (a stacked block) with numerous elements having the aforementioned pattern arranged on one surface.

[0159] In addition, although the case where the insulating layer is formed by printing the ceramic paste in the region where the conductive paste layer is not formed is described here, the insulating layer forming step may be omitted.

[0160] However, from the perspective of increasing the thickness of the coil conductor, it is preferable to form an insulating layer around the conductor paste layer. If there is no insulating layer around the conductor paste layer, the conductor paste layer may be greatly compressed and deformed during the WIP process, and the thickness of the coil conductor may be reduced.

[0161] Next, the laminated body block is cut by a dicing machine or the like to be individualized into devices.

[0162] This element corresponds to one laminated coil component.

[0163] Next, the unfired laminate is fired to produce a fired laminate.

[0164] Specifically, the element is fired at a temperature of 900° C. or higher and 920° C. or lower for one hour or higher and four hours or lower to obtain a fired laminate.

[0165] By this firing, the insulator sheet and the insulating layer are integrated to form an insulator portion.

[0166] Furthermore, the resin paste layer is burned off, and a gap is formed between the insulator portion and the first main surface of the coil conductor.

[0167] Furthermore, since the conductive paste layer shrinks further than the insulator sheet and the insulating layer during firing, a gap is formed locally between the second main surface of the coil conductor and the insulator portion, at a position facing the via conductor. This gap can be formed without relying on a dedicated process.

[0168] Next, the fired laminated components, along with the media, are placed in a drum machine and rotated to perform a roller treatment. This process rounds corners and edges of the components. Rolling can be performed on both unfired components and fired laminated components. Rolling can be done dry or wet. Rolling can be performed by rubbing the components together or by rolling them together with the media.

[0169] Then, external electrodes are formed on the outer surface of the fired laminate.

[0170] Specifically, first, a conductive paste containing metal (eg, silver) and glass is applied to the end surface of the lead-out coil of the fired laminate, and fired at a temperature of 800° C. to 820° C. to form a base electrode.

[0171] Next, a Ni coating and a Sn coating are sequentially formed on the base electrode by electrolytic plating to form a first external electrode and a second external electrode, thereby obtaining a laminated coil component.

[0172] The thickness of the Ni film and the Sn film is, for example, approximately 3 μm respectively.

[0173] As above, Figure 1 The laminated coil component shown.

[0174] The dimensions of the laminate are, for example, L=1.6 mm, W=0.8 mm, and T=0.8 mm.

[0175] [Second embodiment]

[0176] In the second embodiment, a description will be given of a mode (double pattern) in which each coil conductor is configured to include a plurality of coil conductors electrically connected in parallel, unlike the first embodiment (single pattern).

[0177] Figure 12 It is an LT cross-sectional view schematically showing an example of the internal structure of the laminated coil component according to the second embodiment. Figure 12 It is an LT cross-sectional view of a portion where a via conductor is formed.

[0178] In the present embodiment, each of the plurality of coil conductors 31 electrically connected in series via the via conductors 33 includes two coil conductors (hereinafter referred to as parallel-connected coils) 81 electrically connected in parallel via the via conductors 83 .

[0179] This reduces the DC resistance of the coil 30 , making it possible to suitably use the laminated coil component in applications requiring a higher current, such as for in-vehicle use.

[0180] Each parallel-connected coil 81 constituting the coil conductor 31 is a ring-shaped (C-shaped) conductor with one portion missing, thereby partially leaving a gap 37. The two parallel-connected coils 81 constituting the same coil conductor 31 have substantially the same planar shape and are stacked so as to overlap one another so that the positions of their gaps 37 are substantially aligned in the winding direction of the coil 30. Each parallel-connected coil 81 typically has a larger linear width than thickness.

[0181] Each coil conductor 31 is formed by electrically connecting two parallel-connected coils 81 in parallel via a plurality of via conductors 83 .

[0182] In more detail, two conducting conductors 83 are provided between two adjacent parallel-connected coils 81 in the stacking direction. One conducting conductor 83 electrically connects one end of the parallel-connected coil 81 below it to one end of the parallel-connected coil 81 above it, and the other conducting conductor 83 electrically connects the other end of the parallel-connected coil 81 below it to the other end of the parallel-connected coil 81 above it.

[0183] Each via conductor 83 is a columnar conductor extending in the stacking direction. The side surface of each via conductor 83 can be as follows: Figure 12 The shape shown is an inverted cone, but it can also be a right cone or vertical.

[0184] Furthermore, the number of the via conductors 83 connecting the two parallel-connected coils 81 may be three or more.

[0185] exist Figure 12 The diagram shows coil conductors 31 (31a, 31b, 31c, 31d) that constitute coil 30, conducting conductors 33 (33a, 33b, 33c) that connect adjacent coil conductors 31, parallel-connected coils 81 that constitute each coil conductor 31, and conducting conductor 83 that connects two parallel-connected coils 81 that constitute the same coil conductor 31. Coil conductors 31a, 31b, 31c, and 31d each represent one turn of coil conductor 30.

[0186] The maximum thickness of each parallel-connected coil 81 in the stacking direction is preferably 8 μm or more and 28 μm or less, and more preferably 13 μm or more and 23 μm or less.

[0187] The dimension of each via conductor 83 in the stacking direction (the thickness of the insulator portion 40 between two adjacent parallel-connected coils 81 in the stacking direction) is preferably 5 μm or more and 30 μm or less, more preferably 10 μm or more and 25 μm or less.

[0188] Each parallel-connected coil 81 has a first main surface 32a facing downward in the opposite direction to the stacking direction and a second main surface 32b facing upward in the stacking direction. The first main surface 32a is a main surface on the mounting surface side.

[0189] The first principal surface 32 a and the second principal surface 32 b of each parallel-connected coil 81 are parallel to the first principal surface 13 and the second principal surface 14 of the laminate 10 .

[0190] In addition, Figure 12 , similarly to the first embodiment, a configuration is shown in which a gap 50 is provided between the first main surface 32 a of each parallel-connected coil 81 and the insulator portion 40 .

[0191] Therefore, in this embodiment as well, the internal stress of the laminated body 10 can be effectively relaxed.

[0192] From the viewpoint of effectively alleviating the internal stress of the laminate 10, Figure 12 As shown, it is preferable to provide the gap 50 on the first main surface 32 a side of all parallel-connected coils 81 , but it is sufficient if the gap 50 exists between the first main surface 32 a of at least one parallel-connected coil 81 of each coil conductor 31 and the insulator portion 40 .

[0193] And, in Figure 12 , a configuration is shown in which a gap 60 is provided between the second main surface 32 b of each coil conductor 31 and the insulator portion 40 (however, only at a position facing the via conductor 33 ).

[0194] Figure 13 LT is a cross-sectional view schematically showing an example of a first coil conductor and a second coil conductor of the laminated coil component according to the second embodiment. Figure 13 It is an LT cross-sectional view of a portion where a via conductor is formed.

[0195] exist Figure 13, coil conductors 31b and 31c are shown as an example of the first coil conductor and the second coil conductor of the present invention, and the conductive conductor 33b is shown as an example of the first conductive conductor of the present invention, but the same applies to the other two coil conductors 31 adjacent to each other in the stacking direction, and the other conductive conductors 33 sandwiched therebetween.

[0196] like Figure 13 As shown, similar to the first embodiment, the first coil conductor 31b and the second coil conductor 31c are adjacent to each other in the stacking direction and are electrically connected in series via the first conductive conductor 33b. The first coil conductor 31b, the first conductive conductor 33b and the second coil conductor 31c are arranged in sequence in the stacking direction.

[0197] On the other hand, the second coil conductor 31 c includes two parallel-connected coils (coil conductors) 81 electrically connected in parallel via a plurality of second via conductors 83 c.

[0198] Specifically, the first main surface 32 a of the upper parallel-connected coil 81 and the second main surface 32 b of the lower parallel-connected coil 81 are electrically connected via two second via conductors 83 c .

[0199] Furthermore, the first coil conductor 31 b includes two parallel-connected coils (coil conductors) 81 electrically connected in parallel via a plurality of third via conductors 83 b .

[0200] Specifically, the first main surface 32 a of the upper parallel-connected coil 81 and the second main surface 32 b of the lower parallel-connected coil 81 are electrically connected via two third via conductors 83 b .

[0201] As described above, the gap 50 exists between the first main surface 32 a of each parallel-connected coil 81 and the insulator portion 40 .

[0202] Furthermore, similar to the first embodiment, the second coil conductor 31 c has a second main surface 32 b having a gap 60 between it and the insulator portion 40 , and the gap 60 is partially present at a position facing the first via conductor 33 b .

[0203] Therefore, similarly to the first embodiment, it is possible to further relax the internal stress while ensuring the required strength of the stacked body 10 .

[0204] Furthermore, in this embodiment, the air gap 60 can be formed without adding a step for providing the air gap 60 , so the laminated coil component 1 can be manufactured with good productivity.

[0205] In this embodiment, the volume of the conductive bonding portion can be further increased compared to the first embodiment, and the shrinkage of the conductive bonding portion during firing can be further increased, so the gap 60 can be formed more effectively.

[0206] Here, the second principal surface 32 b of the second coil conductor 31 c with the gap 60 between it and the insulator portion 40 refers to the second principal surface 32 b of the upper parallel-connected coil 81 of the two parallel-connected coils 81 constituting the second coil conductor 31 c .

[0207] Figure 14 It is a plan view schematically showing an example of a via conductor portion of the laminated coil component according to the second embodiment.

[0208] like Figure 14 As shown, the second via conductor 83 c overlaps with the first via conductor 33 b when viewed from the stacking direction, and the third via conductor 83 b overlaps with the first via conductor 33 b when viewed from the stacking direction.

[0209] Therefore, the shrinkage of the conductive joint during firing can be further increased, and the gap 60 on the second main surface 32 b of the second coil conductor 31 c can be formed more reliably.

[0210] In addition, the second conductive conductor 83c overlapping with the first conductive conductor 33b is any one of the multiple second conductive conductors 83c, among which the second conductive conductor 83c is preferably a second conductive conductor that connects the ends of one side of the two parallel-connected coils 81 included in the second coil conductor 31c (connecting the ends of one side of the first conductive conductor 33b).

[0211] In addition, the third conductive conductor 83b overlapping with the first conductive conductor 33b is any one of the multiple third conductive conductors 83b, among which the third conductive conductor that connects the ends of one side of the two parallel-connected coils 81 included in the first coil conductor 31b (connecting the ends of one side of the first conductive conductor 33b) is preferably connected.

[0212] like Figure 14 As shown, the first, second and third via conductors 33b, 83c and 83b may be arranged at substantially the same position when viewed in plan from the stacking direction.

[0213] This can further increase the shrinkage of the conductive joint during firing, and can more reliably form the gap 60 on the second main surface 32 b of the second coil conductor 31 c .

[0214] Furthermore, the first, second, and third via conductors 33b, 83c, and 83b may have substantially the same shape and be arranged at substantially the same position when viewed from above in the stacking direction. In other words, the areas occupied by the first, second, and third via conductors 33b, 83c, and 83b may substantially coincide with each other when viewed from above in the stacking direction.

[0215] Preferred planar shapes of the second and third via conductors 83c and 83b include, for example, the same shapes as those of the first via conductor 33b, namely, n-gons (n ​​is an integer greater than or equal to 3, for example, 3 to 8, preferably 4 to 6), circles, ellipses, and curved shapes such as ovals.

[0216] The gap that exists locally at a position opposite to the via conductor is most susceptible to the shrinkage of the nearest via conductor. Figure 13 as well as Figure 14 In the example shown, the void 60 may be generally located within the arrangement region of the second via conductor 83c when viewed from above in the stacking direction, and may have substantially the same shape as the second via conductor 83c. However, the void 60 may also be located within the arrangement region of the first via conductor 33b when viewed from above in the stacking direction, and may have substantially the same shape as the first via conductor 33b. Furthermore, the void 60 may also be located within the arrangement region of the third via conductor 83b when viewed from above in the stacking direction, and may have substantially the same shape as the third via conductor 83b.

[0217] exist Figure 13 as well as Figure 14 In the example shown, no gap exists at a position facing the first via conductor 33b on the second main surface 32b of the parallel-connected coil 81 below the second coil conductor 31c because the second via conductor 83c is present.

[0218] Similarly, no gap exists at a position opposing the third via conductor 83 b on the second main surface 32 b of the parallel-connected coil 81 above the first coil conductor 31 b because of the presence of the first via conductor 33 b .

[0219] exist Figure 13 as well as Figure 14 In the example shown, the maximum thickness of the gap 60 on the second main surface 32b of the second coil conductor 31c in the lamination direction is preferably 2 μm or more and 15 μm or less, more preferably 4 μm or more and 6 μm or less.

[0220] Figure 15 It is an LT cross-sectional view schematically showing another example of the first coil conductor and the second coil conductor of the laminated coil component according to the second embodiment. Figure 15 It is an LT cross-sectional view of a portion where a via conductor is formed.

[0221] exist Figure 15, coil conductors 31b and 31c are shown as an example of the first coil conductor and the second coil conductor of the present invention, and the conductive conductor 33b is shown as an example of the first conductive conductor of the present invention, but the same applies to the other two coil conductors 31 adjacent to each other in the stacking direction, and the other conductive conductors 33 sandwiched therebetween.

[0222] Figure 15 In the example shown, the second and third via conductors 83c and 83b are slightly offset from the first via conductor 33b, and the second and third via conductors 83c and 83b partially overlap with the first via conductor 33b. Figure 13 The examples shown are different.

[0223] exist Figure 15 In the illustrated example, the second coil conductor 31 c also has the second main surface 32 b with the gap 60 between it and the insulator portion 40 , and the gap 60 is partially present at a position facing the first via conductor 33 b .

[0224] However, the gap 60 is Figure 13 In the example shown, the second coil conductor 31c is present between the second main surface 32b of the upper parallel-connected coil 81 and the insulator portion 40, but Figure 15 In the illustrated example, the second coil conductor 31 c exists between the second main surface 32 b of the lower parallel-connected coil 81 and the insulator portion 40 .

[0225] In addition, Figure 15 In the illustrated example, the second coil conductor 31c has a second main surface 32b with a gap 61 between it and the insulator portion 40. The gap 61 is partially located at a position opposite the second via conductor 83c. This second main surface 32b with the gap 61 between it and the insulator portion 40 refers to the second main surface 32b of the upper parallel-connected coil 81 of the two parallel-connected coils 81 that constitute the second coil conductor 31c.

[0226] And, in Figure 15 In the illustrated example, the first coil conductor 31b has a second main surface 32b with a gap 62 between it and the insulator portion 40. The gap 62 is partially located at a position opposite the third via conductor 83b. This second main surface 32b with the gap 62 between it and the insulator portion 40 refers to the second main surface 32b of the upper parallel-connected coil 81 of the two parallel-connected coils 81 constituting the first coil conductor 31b.

[0227] In this example, since there are gaps 60 to 62, Figure 13As in the example shown, it is possible to further relax the internal stress while ensuring the required strength of the laminate 10 .

[0228] Furthermore, in this example as well, the gaps 60 to 62 can be formed without adding a step for providing the gaps 60 to 62 , so the laminated coil component 1 can be manufactured with good productivity.

[0229] Figure 16 It is a plan view schematically showing another example of the through-conductor portion of the laminated coil component according to the second embodiment. Figure 16 Showing a bird's-eye view Figure 15 An example of the state of the example shown.

[0230] like Figure 16 As shown, the second via conductor 83c partially overlaps the first via conductor 33b when viewed from the stacking direction, and the third via conductor 83b partially overlaps the first via conductor 33b when viewed from the stacking direction.

[0231] In addition, the second conductive conductor 83c that partially overlaps with the first conductive conductor 33b is any one of a plurality of second conductive conductors 83c, preferably a second conductive conductor that connects the ends of one side of the two parallel-connected coils 81 included in the second coil conductor 31c (connects the ends of one side of the first conductive conductor 33b).

[0232] In addition, the third conductive conductor 83b that partially overlaps with the first conductive conductor 33b is any one of a plurality of third conductive conductors 83b, preferably a third conductive conductor that connects the ends of one side of the two parallel-connected coils 81 included in the first coil conductor 31b (connects the ends of one side of the first conductive conductor 33b).

[0233] As described above, the gap that exists locally at a position facing the via conductor is most susceptible to the shrinkage of the nearest via conductor. Figure 15 as well as Figure 16 In the example shown, the gap 60 is generally included in the area where the first via conductor 33b is located when viewed from above in the stacking direction. However, because the second via conductor 83c is partially located opposite the first via conductor 33b, the gap 60 is generally included in the area where the first via conductor 33b is located and does not overlap with the second via conductor 83c when viewed from above in the stacking direction.

[0234] The gap 61 may be included in the arrangement region of the second via conductor 83 c when viewed in a plan view generally from the stacking direction, and may have substantially the same shape as that of the second via conductor 83 c .

[0235] When viewed from above in the stacking direction, the gap 62 is usually included in the area where the third via conductor 83b is located. However, since the first via conductor 33b is partially located opposite the third via conductor 83b, the gap 62 is usually included in the area where the third via conductor 83b is located and does not overlap with the first via conductor 33b when viewed from above in the stacking direction.

[0236] exist Figure 15 as well as Figure 16 In the example shown, the maximum thickness in the lamination direction of the gap 60 on the second main surface 32b of the parallel-connected coil 81 below the second coil conductor 31c is preferably 1 μm or more and 10 μm or less.

[0237] Furthermore, it is preferable that the maximum thickness in the lamination direction of the gap 61 on the second main surface 32 b of the parallel-connected coil 81 above the second coil conductor 31 c is 1 μm or more and 10 μm or less.

[0238] Furthermore, it is preferable that the maximum thickness of the gap 62 in the lamination direction on the second main surface 32 b of the parallel-connected coil 81 above the first coil conductor 31 b is 1 μm or more and 10 μm or less.

[0239] Figure 17 It is an LT cross-sectional view schematically showing another example of the first coil conductor and the second coil conductor of the laminated coil component according to the second embodiment. Figure 17 It is an LT cross-sectional view of a portion where a via conductor is formed.

[0240] exist Figure 17 , coil conductors 31b and 31c are shown as an example of the first coil conductor and the second coil conductor of the present invention, and the conductive conductor 33b is shown as an example of the first conductive conductor of the present invention, but the same applies to the other two coil conductors 31 adjacent to each other in the stacking direction, and the other conductive conductors 33 sandwiched therebetween.

[0241] Figure 17 In the example shown, the second and third via conductors 83c and 83b are arranged at positions offset from the first via conductor 33b, and the first, second and third via conductors 33b, 83c and 83b do not overlap with each other. Figure 13 as well as Figure 15 The examples shown are different.

[0242] exist Figure 17 In the example shown, Figure 15Similar to the example shown, the second coil conductor 31c (the parallel-connected coil 81 constituting the lower side of the second coil conductor 31c) has a second main surface 32b with a gap 60 between it and the insulator portion 40, and the gap 60 is partially present at a position opposite to the first conducting conductor 33b.

[0243] The second coil conductor 31c (the parallel-connected coil 81 above the second coil conductor 31c) has a second main surface 32b with a gap 61 between it and the insulator portion 40. The gap 61 is partially located at a position facing the second via conductor 83c.

[0244] Furthermore, the first coil conductor 31b (the parallel-connected coil 81 forming the upper side of the first coil conductor 31b) has a second main surface 32b having a gap 62 between it and the insulator portion 40. The gap 62 is partially present at a position facing the third via conductor 83b.

[0245] In this example, there are also gaps 60 to 62, so Figure 15 As in the example shown, it is possible to further relax the internal stress while ensuring the required strength of the laminate 10 .

[0246] Furthermore, in this example as well, the gaps 60 to 62 can be formed without adding a step for providing the gaps 60 to 62 , so the laminated coil component 1 can be manufactured with good productivity.

[0247] Figure 18 It is a plan view schematically showing another example of the through-conductor portion of the laminated coil component according to the second embodiment. Figure 18 Showing a bird's-eye view Figure 17 An example of the state of the example shown.

[0248] like Figure 18 As shown, a plurality of second conducting conductors 83c (in Figure 18 Only one is shown in the figure) does not overlap with the first via conductor 33b when viewed from the stacking direction, and the plurality of third via conductors 83b (in Figure 18 Only one is shown in the figure, and none of them overlaps with the first via conductor 33b when viewed from the stacking direction.

[0249] exist Figure 17 as well as Figure 18 In the example shown, the gap 60 may be included in the arrangement region of the first via conductor 33 b when generally viewed in a planar manner from the stacking direction, and may have substantially the same shape as that of the first via conductor 33 b .

[0250] Alternatively, the gap 61 may be included in the arrangement region of the second via conductor 83 c when viewed in a plan view generally from the stacking direction, and may have substantially the same shape as that of the second via conductor 83 c .

[0251] Furthermore, the gap 62 may be included in the arrangement region of the third via conductor 83 b when viewed in a plan view normally from the stacking direction, and may have substantially the same shape as that of the third via conductor 83 b .

[0252] exist Figure 17 as well as Figure 18 In the example shown, the maximum thickness in the lamination direction of the gap 60 on the second main surface 32b of the parallel-connected coil 81 below the second coil conductor 31c is preferably 1 μm or more and 10 μm or less.

[0253] Furthermore, it is preferable that the maximum thickness in the lamination direction of the gap 61 on the second main surface 32 b of the parallel-connected coil 81 above the second coil conductor 31 c is 1 μm or more and 10 μm or less.

[0254] Furthermore, it is preferable that the maximum thickness of the gap 62 in the lamination direction on the second main surface 32 b of the parallel-connected coil 81 above the first coil conductor 31 b is 1 μm or more and 10 μm or less.

[0255] Figures 15-18 The maximum thickness of each gap 60, 61, 62 in the stacking direction in the example shown is Figure 13 as well as Figure 14 The maximum thickness of the gap 60 in the stacking direction in the example shown may be different from or smaller than that in the example shown. This is because the shrinkage of the conductive junction tends to be smaller in the former than in the latter.

[0256] Next, a method for manufacturing the laminated coil component according to this embodiment will be described.

[0257] Basically, it is possible to form two Figures 7 to 10 The coil pieces 71a, 71b, 71c, and 71d described above are stacked together to form a laminated coil component according to this embodiment.

[0258] However, in the insulator sheet between the two parallel-connected coils 81 connected in parallel, conduction holes are formed at two locations corresponding to one end and the other end of these parallel-connected coils 81 .

Claims

1. A laminated coil component comprising: a laminated body having a coil provided inside an insulating body portion formed by laminating a plurality of insulating layers; and An external electrode is provided on the outer surface of the stack and is electrically connected to the coil. It is characterized by: The coil is formed by electrically connecting a plurality of coil conductors stacked together with the plurality of insulating layers via a conducting conductor. Each of the plurality of coil conductors has a first main surface facing the opposite side to the stacking direction and a second main surface facing the stacking direction. The plurality of coil conductors include a first coil conductor and a second coil conductor adjacent to each other in the stacking direction. The first coil conductor and the second coil conductor are electrically connected in series via a first via conductor. The first coil conductor, the first via conductor, and the second coil conductor are sequentially arranged in the stacking direction. The first coil conductor has a first main surface with a gap between the first main surface and the insulator portion. The second coil conductor has a first main surface with a gap between it and the insulator portion, and a second main surface with a gap between it and the insulator portion. The gap between the second main surface of the second coil conductor and the insulator portion exists locally at a position facing the first via conductor.

2. The laminated coil component according to claim 1, wherein A ratio of a width of the gap locally located at a position facing the first via conductor in a direction perpendicular to the stacking direction to a width of the first via conductor in the direction perpendicular to the stacking direction is greater than or equal to 0.5 and less than or equal to 1.

0.

3. The laminated coil component according to claim 1 or 2, wherein: The second coil conductor includes two coil conductors electrically connected in parallel via a plurality of second via conductors.

4. The laminated coil component according to claim 3, wherein When viewed in plan from the stacking direction, any one of the plurality of second via conductors overlaps with the first via conductor.

5. The laminated coil component according to claim 1 or 2, wherein: The first coil conductor includes two coil conductors electrically connected in parallel via a plurality of third via conductors.

6. The laminated coil component according to claim 5, wherein: When viewed in plan from the stacking direction, any one of the plurality of third via conductors overlaps with the first via conductor.

7. The laminated coil component according to claim 1 or 2, wherein: The coil has a void area ratio of not less than 5% and not more than 15%.

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