JP5240221B2 - Multilayer inductor and method for manufacturing multilayer inductor - Google Patents

Description

  The present invention relates to a multilayer inductor and a method for manufacturing the same.

  As a conventional multilayer inductor, one having a multilayer structure in which a plurality of insulator layers are stacked and a coil configured by connecting conductor patterns to each other in the multilayer body is known (for example, Patent Document 1). The conductor pattern of this multilayer inductor is formed thick by laminating a plurality of internal electrode layers. Specifically, one thick conductor pattern is formed by preparing a plurality of green sheets on which internal electrode layers having the same pattern are formed and laminating them.

JP 2001-358018 A

  Here, as one of the methods for manufacturing the multilayer inductor having the above-described configuration, the conductive coating film that forms the internal electrode layer and the insulating coating film that forms the insulating layer on the base insulating sheet. A method of forming the internal electrode layer and the insulator layer by repeating the steps of applying and drying, and repeating the steps of applying and drying the conductive coating film and the insulator coating film thereon and then drying can be considered. However, when such a manufacturing method is adopted, the following problems may occur. That is, tensile stress is generated between the internal electrode layer and the insulator layer due to drying / shrinkage during manufacturing. In the above-described multilayer inductor, a single conductor pattern is formed by stacking a plurality of internal electrode layers. Therefore, when such a manufacturing method is adopted, drying and shrinkage are repeatedly performed for each internal electrode layer. Accordingly, an insulator sheet disposed between conductor patterns (a sheet serving as a base when applying a conductive coating film forming an internal electrode layer and an insulating coating film forming an insulator layer) There was a possibility that stress would be concentrated on the surface. When stress concentrates on the insulator sheet, the insulator sheet may crack, and the conductor patterns may be short-circuited in the stacking direction.

  The present invention has been made to solve the above problems, and provides a multilayer inductor capable of preventing the occurrence of cracks in an insulating layer between conductor patterns and improving reliability. With the goal.

  The multilayer inductor according to the present invention includes a multilayer body configured by laminating a plurality of insulator layers and a plurality of strip-like conductor patterns that are electrically connected to each other, and is disposed inside the multilayer body. A conductor pattern, wherein the conductor pattern is formed by laminating a plurality of internal electrode layers in the laminating direction of the laminated body, and a first portion arranged on one side in the laminating direction, and in the laminating direction A second portion disposed on the other side, the first portion has at least a first internal electrode layer disposed on the most one side in the stacking direction among the plurality of internal electrode layers, and the second portion is , Having a side surface that contacts the multilayer body in the width direction of the conductor pattern, the first portion has an end surface that contacts the multilayer body on one side in the stacking direction, and an end in the width direction of the end surface is viewed from the stacking direction. Side and heavy And characterized by the absence.

  In the multilayer inductor according to the present invention, the conductor pattern is formed thick by laminating a plurality of internal electrode layers. The conductor pattern has a first portion on one side in the stacking direction and a second portion on the other side. The first part has a first internal electrode arranged on the most side in the stacking direction. That is, the first portion is a portion that comes into contact with an insulator layer (hereinafter referred to as an insulator sheet) disposed between other conductor patterns. The first part has an end surface that comes into contact with the laminate on one side in the laminating direction, and this end surface is a surface that comes into contact with the insulator sheet. Here, the 2nd part has the side surface which contacts a laminated body in the width direction of a conductor pattern. In this aspect, drying and shrinkage are performed between the internal electrode layer and the insulator layer during manufacturing. Here, at the time of manufacture, drying and shrinkage are repeatedly performed for each internal electrode layer constituting the conductor pattern. Therefore, when the second part is configured by laminating a plurality of internal electrode layers formed in the same pattern, stress is easily concentrated in a region overlapping the side surface of the second part in the laminating direction. Moreover, since the edge in the width direction of the end face of the first part is also a boundary part between the internal electrode layer and the insulator sheet, stress is easily concentrated. However, the end in the width direction of the end surface of the first portion does not overlap the side surface of the second portion when viewed from the stacking direction. That is, an insulator layer and an internal electrode layer are disposed between the insulator sheet and the side surface of the second portion in the stacking direction instead of the end of the first portion where stress is easily concentrated. Therefore, the stress from the side surface of the second portion is dispersed and relaxed by the insulator layer and the internal electrode layer. As described above, it is possible to prevent the insulator layer between the conductor patterns from being cracked and improve the reliability.

  In addition, the multilayer inductor according to the present invention may be a conductor pattern of a type in which the side surface of the second part has an uneven shape, or a conductor pattern of a type in which the side surface has a flat shape. Also, the occurrence of cracks can be prevented.

  Further, in the multilayer inductor according to the present invention, the first portion has a peripheral surface that is in contact with the multilayer body in the width direction and connected to the end surface, and the peripheral surface is curved so as to enter the conductor pattern side, It is preferable that the end in the width direction of the end surface is disposed on the inner side in the width direction than the side surface. Such a first portion is formed by forming an insulating coating film on the insulating sheet so that a narrow exposed portion is formed before forming the conductive coating film on the insulating sheet during manufacturing. Is formed by forming a conductive coating film. That is, the presence of the narrow exposed portion makes it possible to dispose the end of the first portion on the inner side in the width direction than the side surface of the second portion regardless of the size and shape of the conductive coating film. According to such a structure, a desired shape can be obtained even when a printing plate making of the same size as that used in the second part is used when forming the conductive coating film for constituting the first part. it can. Further, when the width of the first portion is larger than that of the second portion, or when the position of the first portion in the width direction is shifted with respect to the second portion, the inner diameter of the coil becomes narrow and the magnetic path becomes narrow. There is a possibility. However, since the end of the first portion is disposed on the inner side in the width direction than the side surface of the second portion, the characteristics of the coil can be maintained. As described above, the structure according to the present invention can be applied without being restricted in coil design.

  The method for manufacturing a multilayer inductor according to the present invention includes a multilayer body configured by laminating a plurality of insulator layers and a plurality of strip-shaped conductor patterns electrically connected to each other, and is provided inside the multilayer body. A conductive pattern is formed by laminating a plurality of internal electrode layers in the stacking direction of the stack, the first portion disposed on one side in the stacking direction, and the other side in the stacking direction A laminated inductor having a second portion disposed on the sheet constituting the insulator layer, the first conductive coating film constituting the internal electrode layer in the first portion, and the insulator layer Forming a first insulator coating film, forming a first portion; a second conductive coating film forming an internal electrode layer in the second portion; and a second insulator coating forming an insulator layer. To form a film And a step of forming a second portion, wherein the second conductive coating film has a side surface in contact with the second insulator coating film in the width direction of the conductor pattern, and the first conductive coating film is a sheet. The end surface in the width direction of the end surface does not overlap the side surface when viewed from the stacking direction.

  In the method for manufacturing a multilayer inductor according to the present invention, the conductor pattern can be made thick by laminating a plurality of internal electrode layers. Here, the 2nd conductive coating film which comprises a 2nd part has a side surface which contacts the 2nd insulator coating film which comprises the insulator layer of a laminated body in the width direction of a conductor pattern. In the said side, drying and shrinkage | contraction are performed between a 2nd conductive coating film and a 2nd insulator coating film. Here, when forming a conductor paste using a some conductive coating film, drying and shrinkage | contraction are repeatedly performed for every conductive coating film. Therefore, when the second part is configured by laminating a plurality of second conductive coating films formed in the same pattern, stress is concentrated in a region overlapping the side surface of the second conductive coating film in the stacking direction. It becomes easy. Moreover, since the edge in the width direction of the end surface of the first conductive coating film constituting the first portion is also a boundary portion between the first conductive coating film and the insulator sheet, stress is easily concentrated. However, the end in the width direction of the end surface of the first conductive coating film constituting the first portion does not overlap the side surface of the second conductive coating film as viewed from the stacking direction. That is, in the laminating direction, instead of the end of the first conductive coating film where stress is easily concentrated between the insulator sheet and the side surface of the second conductive coating film, the first insulating coating film or the first conductive coating film is used. A membrane is placed. Therefore, the stress from the side surface of the second conductive coating film is relaxed by the first insulator coating film and the first conductive coating film. Further, by manufacturing in this way, after firing to complete the multilayer inductor, the stress from the side surface of the second portion is dispersed and relaxed by the insulator layer and the internal electrode layer. As described above, cracks can be prevented from occurring in the insulator layer between the conductor patterns, and the reliability of the multilayer inductor can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that a crack arises in the insulator layer between conductor patterns, and can improve reliability.

1 is a perspective view showing a multilayer inductor according to an embodiment. It is a disassembled perspective view for demonstrating the structure of the laminated body with which the multilayer inductor which concerns on this embodiment is provided. It is a disassembled perspective view which expands and shows a part of FIG. It is sectional drawing which cut | disconnected the laminated body along the IV-IV line | wire shown in FIG. It is the expanded sectional view which expanded the part shown to WV of FIG. It is a figure which shows 1 process of the manufacturing method of the multilayer inductor which concerns on this embodiment. It is an expanded sectional view which shows the conductor pattern of the multilayer inductor which concerns on a comparative example. It is an expanded sectional view which shows the conductor pattern of the multilayer inductor which concerns on a modification. It is an expanded sectional view which shows the conductor pattern of the multilayer inductor which concerns on a modification. It is an expanded sectional view which shows the conductor pattern of the multilayer inductor which concerns on a modification.

  Preferred embodiments of the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and a duplicate description is omitted.

(Configuration of multilayer inductor)
First, the configuration of the multilayer inductor 10 according to the present embodiment will be described with reference to FIGS. As shown in FIGS. 1 and 2, the multilayer inductor 10 includes a substantially rectangular parallelepiped multilayer body 12, a pair of external electrodes 14 and 16 formed on both side surfaces of the multilayer body 12 in the longitudinal direction, Inside the body 12, a conductor pattern C1 to C12 is provided with a coil L that is electrically connected to each other.

  The laminated body 12 has a pair of main surfaces 12a and 12b facing each other so as to be substantially parallel to each other. One of the main surfaces 12a and 12b is a surface facing the external substrate when the multilayer inductor 10 is mounted on the external substrate (not shown).

  As shown in FIG. 2, the laminated body 12 is formed by laminating magnetic layers A1 to A4, nonmagnetic layer B1, magnetic layers A5 to A7, nonmagnetic layer B2, and magnetic layers A8 to A12 in this order. It is composed by. That is, the upper surface of the magnetic layer A1 constitutes the main surface 12a of the multilayer body 12, the lower surface of the magnetic layer A12 constitutes the main surface 12b of the multilayer body 12 (see FIG. 2), and the main surfaces 12a and 12b. The facing direction (hereinafter referred to as the facing direction) of the laminated body 12 (hereinafter referred to as the stacking direction) of the stacked body 12 (magnetic layers A1 to A12 and nonmagnetic layers B1 and B2) in the present embodiment.

  The magnetic layers A1 to A12, the nonmagnetic layers B1 and B2, and magnetic films F1 to F10 described later function as an insulator having electrical insulation. The magnetic layers A1 to A12 and the magnetic films F1 to F10 may be formed using ferrite such as Ni—Cu—Zn based ferrite, Cu—Zn based ferrite, or Ni—Cu—Zn—Mg based ferrite, for example. it can. The nonmagnetic layers B1 and B2 can be formed using nonmagnetic ferrite such as Cu—Zn nonmagnetic ferrite, for example. In the actual multilayer inductor 1, the boundaries of the magnetic layers A1 to A12, the nonmagnetic layers B1 and B2, and the magnetic films F1 to F10 are integrated so as not to be visible.

  A conductor pattern C1 and a lead conductor D1 are formed on the surface of the magnetic layer A2. The conductor pattern C1 is disposed so as to be positioned at one end of the coil L. A lead conductor D1 is integrally formed at one end of the conductor pattern C1. The lead conductor D1 is drawn to the edge of the magnetic layer A2 on the side where the external electrode 14 is formed, and its end is exposed on the end face of the magnetic layer A2. For this reason, the conductor pattern C1 is electrically connected to the external electrode 12 through the lead conductor D1. The other end of the conductor pattern C1 is electrically connected to a columnar through-hole conductor E1 formed through the magnetic layer A2 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C1 is electrically connected to the corresponding conductor pattern C2 through the through-hole conductor E1 and the connection conductor G1 in a stacked state.

  A conductor pattern C2 and a magnetic film F1 are formed on the surface of the magnetic layer A3. The conductor pattern C2 has a strip shape, corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A3. One end of the conductor pattern C2 is provided with a connection conductor G1 on the surface, and this connection conductor G1 is connected to the through-hole conductor E1 in a stacked state. That is, the conductor pattern C2 has an end connected to the through-hole conductor E1 via the connection conductor G1. The other end of the conductor pattern C2 is electrically connected to a columnar through-hole conductor E2 formed through the magnetic layer A3 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C2 is electrically connected to the corresponding conductor pattern C3 through the through-hole conductor E2 and the connection conductor G2 in a stacked state.

  A conductor pattern C3 and a magnetic film F2 are formed on the surface of the magnetic layer A4. The conductor pattern C3 has a strip shape, corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A4. A connection conductor G2 is provided on one surface of the conductor pattern C3, and the connection conductor G2 is connected to the through-hole conductor E2 in a stacked state. That is, the conductor pattern C3 has an end connected to the through-hole conductor E2 via the connection conductor G2. The other end of the conductor pattern C3 is electrically connected to a cylindrical through-hole conductor E3 formed through the magnetic layer A4 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C3 is electrically connected to the corresponding conductor pattern C4 through the through-hole conductor E3 and the connection conductor G3 in a stacked state.

  A conductor pattern C4 and a magnetic film F3 are formed on the surface of the nonmagnetic material layer B1. The conductor pattern C4 has a strip shape, which corresponds to approximately one turn of the coil L, and is wound spirally on the nonmagnetic layer B1. One end of the conductor pattern C4 is provided with a connection conductor G3 on its surface, and this connection conductor G3 is connected to the through-hole conductor E3 in a stacked state. That is, the conductor pattern C4 has an end connected to the through-hole conductor E3 through the connection conductor G3. The other end of the conductor pattern C4 is electrically connected to a columnar through-hole conductor E4 formed through the nonmagnetic layer B1 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C4 is electrically connected to the corresponding conductor pattern C5 through the through-hole conductor E4 and the connection conductor G4 in a stacked state.

  A conductor pattern C5 and a magnetic film F4 are formed on the surface of the magnetic layer A5. The conductor pattern C5 has a strip shape, which corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A5. A connection conductor G4 is provided on the surface of one end of the conductor pattern C5, and this connection conductor G4 is connected to the through-hole conductor E4 in a stacked state. That is, the conductor pattern C5 has an end connected to the through-hole conductor E4 through the connection conductor G4. The other end of the conductor pattern C5 is electrically connected to a cylindrical through-hole conductor E5 formed through the magnetic layer A5 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C5 is electrically connected to the corresponding conductor pattern C6 via the through-hole conductor E5 and the connection conductor G5 in a stacked state.

  A conductor pattern C6 and a magnetic film F5 are formed on the surface of the magnetic layer A6. The conductor pattern C6 has a strip shape, which corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A6. One end of the conductor pattern C6 is provided with a connection conductor G5 on its surface, and this connection conductor G5 is connected to the through-hole conductor E5 in a stacked state. That is, the conductor pattern C6 has an end connected to the through-hole conductor E5 through the connection conductor G5. The other end of the conductor pattern C6 is electrically connected to a columnar through-hole conductor E6 formed through the magnetic layer A6 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C6 is electrically connected to the corresponding conductor pattern C7 through the through-hole conductor E6 and the connection conductor G6 in a stacked state.

  A conductor pattern C7 and a magnetic film F6 are formed on the surface of the magnetic layer A7. The conductor pattern C7 has a strip shape, which corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A7. One end of the conductor pattern C7 is provided with a connection conductor G6 on its surface, and this connection conductor G6 is connected to the through-hole conductor E6 in a stacked state. That is, the conductor pattern C7 has an end connected to the through-hole conductor E6 via the connection conductor G6. The other end of the conductor pattern C7 is electrically connected to a columnar through-hole conductor E7 formed through the magnetic layer A7 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C7 is electrically connected to the corresponding conductor pattern C8 through the through-hole conductor E7 and the connection conductor G7 in a stacked state.

  A conductor pattern C8 and a magnetic film F7 are formed on the surface of the nonmagnetic material layer B2. The conductor pattern C8 has a strip shape, corresponds to approximately one turn of the coil L, and is wound spirally on the nonmagnetic layer B2. One end of the conductor pattern C8 is provided with a connection conductor G7 on its surface, and this connection conductor G7 is connected to the through-hole conductor E7 in a stacked state. That is, the conductor pattern C8 has an end connected to the through-hole conductor E7 via the connection conductor G7. The other end of the conductor pattern C8 is electrically connected to a columnar through-hole conductor E8 formed through the nonmagnetic layer B2 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C8 is electrically connected to the corresponding conductor pattern C9 via the through-hole conductor E8 and the connection conductor G8 in a stacked state.

  A conductor pattern C9 and a magnetic film F8 are formed on the surface of the magnetic layer A8. The conductor pattern C9 has a strip shape, corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A8. One end of the conductor pattern C9 is provided with a connection conductor G8 on its surface, and this connection conductor G8 is connected to the through-hole conductor E8 in a stacked state. That is, the conductor pattern C9 has an end connected to the through-hole conductor E8 via the connection conductor G8. The other end of the conductor pattern C9 is electrically connected to a cylindrical through-hole conductor E9 formed through the magnetic layer A8 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C9 is electrically connected to the corresponding conductor pattern C10 through the through-hole conductor E9 and the connection conductor G9 in a stacked state.

  A conductor pattern C10 and a magnetic film F9 are formed on the surface of the magnetic layer A9. The conductor pattern C10 has a strip shape, corresponds to approximately one turn of the coil L, and is wound spirally on the magnetic layer A9. One end of the conductor pattern C10 is provided with a connection conductor G9 on its surface, and this connection conductor G9 is connected to the through-hole conductor E9 in a stacked state. That is, the conductor pattern C10 has an end connected to the through-hole conductor E9 via the connection conductor G9. The other end of the conductor pattern C10 is electrically connected to a columnar through-hole conductor E10 formed through the magnetic layer A9 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C10 is electrically connected to the corresponding conductor pattern C11 through the through-hole conductor E10 and the connection conductor G10 in a stacked state.

  A conductor pattern C11 and a magnetic film F10 are formed on the surface of the magnetic layer A10. The conductor pattern C11 has a strip shape, which corresponds to approximately 3/8 turn of the coil L, and is formed in an L shape on the magnetic layer A10. One end of the conductor pattern C11 is provided with a connection conductor G10 on the surface thereof, and this connection conductor G10 is connected to the through-hole conductor E10 in a stacked state. That is, the conductor pattern C11 has an end connected to the through-hole conductor E10 via the connection conductor G10. The other end of the conductor pattern C11 is electrically connected to a columnar through-hole conductor E11 formed through the magnetic layer A10 in the thickness direction (that is, extending along the stacking direction). For this reason, the conductor pattern C11 is electrically connected to the corresponding conductor pattern C12 through the through-hole conductor E11 in a stacked state.

  A conductor pattern C12 and a lead conductor D2 are formed on the surface of the magnetic layer A11. One end of the conductor pattern C12 includes a region electrically connected to the through-hole conductor E11 in a stacked state. A lead conductor D2 is integrally formed at the other end of the conductor pattern C12. The lead conductor D2 is drawn to the edge of the magnetic layer A11 on the side where the external electrode 14 is formed, and its end is exposed at the end face of the magnetic layer A11. For this reason, the conductor pattern C12 is electrically connected to the external electrode 14 through the lead conductor D2.

  Next, the configuration of the conductor patterns C2 to C11 will be described in more detail with reference to FIG. FIG. 5 is an enlarged cross-sectional view of a portion indicated by WV in FIG. In FIG. 5, only the cross-sectional shape obtained by cutting one side of the strip-like conductor pattern C6 in the width direction is shown, but the other three sides have the same configuration. The other conductor patterns C2 to C5 and C7 to C11 have the same configuration.

  The conductor patterns C2 to C11 are set to have a thickness of 20 μm or more, and are preferably set to have a thickness of about 40 μm to 80 μm. When the thickness of the conductor patterns C2 to C11 is less than 20 μm, the cross sectional area of the conductor patterns C2 to C11 tends to be relatively small, and the DC resistance value of the multilayer inductor 10 tends to be large. 10 is not suitable for high current applications.

  As shown in FIG. 5, the conductor pattern C6 is configured by laminating a first internal electrode layer 21, a second internal electrode layer 22, a third internal electrode layer 23, and a fourth internal electrode layer 24. . Each internal electrode layer has a first internal electrode layer 21, a second internal electrode layer 22, and a third internal portion from the main surface 12 b side (one side in the stacking direction) to the main surface 12 a side (the other side in the stacking direction). The electrode layer 23 and the fourth internal electrode layer 24 are stacked in this order. That is, the first internal electrode layer 21 is disposed on the most principal surface 12b side in the stacking direction. The second internal electrode layer 22, the third internal electrode layer 23, and the fourth internal electrode layer 24 each have the same cross-sectional shape. The first internal electrode layer 21 has a different cross-sectional shape from the second internal electrode layer 22, the third internal electrode layer 23, and the fourth internal electrode layer 24. Of the conductor pattern C6, a portion constituted by the first internal electrode layer 21 is defined as a first portion 26, and a portion constituted by the second internal electrode layer 22, the third internal electrode layer 23, and the fourth internal electrode layer 24 is defined. Let it be the second portion 27. That is, the conductor pattern C6 includes a first portion 26 disposed on the main surface 12b side in the stacking direction and a second portion 27 disposed on the main surface 12a side in the stacking direction.

  The first internal electrode layer 21 has an end face 31 in contact with the multilayer body 12 (that is, a magnetic layer or a nonmagnetic layer) on the main surface 12b side in the stacking direction. The first internal electrode layer 21 has peripheral surfaces 32A and 32B and peripheral surfaces 33A and 33B that are in contact with the laminate 12 in the width direction. The peripheral surfaces 32A and 32B are connected to the end surface 31, and are curved so as to enter the conductor pattern C6 side. The peripheral surfaces 33A and 33B are connected to the peripheral surfaces 32A and 32B, respectively, and are curved so as to project toward the laminate 12 side. The second internal electrode layer 22 has peripheral surfaces 34A and 34B and peripheral surfaces 35A and 35B that are in contact with the stacked body 12 in the width direction. The peripheral surfaces 34A and 34B are connected to the peripheral surfaces 33A and 33B, respectively, and are curved so as to enter the conductor pattern C6 side. The peripheral surfaces 35A and 35B are connected to the peripheral surfaces 34A and 34B, respectively, and are curved so as to protrude toward the laminate 12 side. The third internal electrode layer 23 includes peripheral surfaces 36A and 36B and peripheral surfaces 37A and 37B that are in contact with the stacked body 12 in the width direction. The peripheral surfaces 36A and 36B are connected to the peripheral surfaces 35A and 35B, respectively, and are curved so as to enter the conductor pattern C6 side. The peripheral surfaces 37A and 37B are connected to the peripheral surfaces 36A and 36B, respectively, and are curved so as to project toward the laminate 12 side. The fourth internal electrode layer 24 has peripheral surfaces 38A and 38B that contact the stacked body 12 in the width direction. The peripheral surfaces 38A and 38B are connected to the peripheral surfaces 37A and 37B, respectively, and are curved so as to enter the conductor pattern C6 side. The fourth internal electrode layer 24 has an end surface 39 on the main surface 12b side in the stacking direction. The end face 39 is connected to the through-hole conductor E5.

  Accordingly, the conductor pattern 6C includes connecting ends 41A and 41B that connect the end surface 31 and the peripheral surfaces 32A and 32B, and connecting ends 42A and 42B that connect the peripheral surfaces 32A and 32B and the peripheral surfaces 33A and 33B, respectively. Connection ends 43A and 43B for connecting 33A and 33B and the peripheral surfaces 34A and 34B, connection ends 44A and 44B for connecting the peripheral surfaces 34A and 34B and the peripheral surfaces 35A and 35B, and the peripheral surfaces 35A and 35B and the peripheral surface, respectively. Connection ends 45A and 45B for connecting 36A and 36B, connection ends 46A and 46B for connecting the peripheral surfaces 36A and 36B and the peripheral surfaces 37A and 37B, and peripheral surfaces 37A and 37B and peripheral surfaces 38A and 38B, respectively. Connection ends 47A and 47B to be connected, and peripheral ends 38A and 38B and end faces 39 are provided with connection ends 48A and 48B, respectively.

  The internal electrode layers 22, 23, and 24 constituting the second portion 27 are configured in the same cross-sectional shape, and are arranged so that the positions in the width direction are the same. As a result, the peripheral surfaces 34A, 35A, 36A, 37A, and 38A form a certain pattern of irregularities. Accordingly, the connecting ends 44A, 46A, and 48A have the same position in the width direction and overlap each other when viewed from the stacking direction. Further, the connecting ends 43A, 45A, 47A have the same position in the width direction and overlap each other when viewed from the stacking direction. Further, the peripheral surfaces 34B, 35B, 36B, 37B, and 38B constitute a certain pattern of uneven shapes. The connecting ends 44B, 46B, and 48B have the same position in the width direction and overlap each other when viewed from the stacking direction. Further, the connecting ends 43B, 45B, and 47B have the same position in the width direction and overlap each other when viewed from the stacking direction. In the present embodiment, the first internal electrode layer 21 is formed using the same printing plate as the other internal electrode layers 22, 23, and 24. Accordingly, the connecting end 43A has the same position in the width direction as the connecting ends 45A and 47A, and the connecting end 43B has the same position in the width direction as the connecting ends 45B and 47B. However, since the shapes of the peripheral surfaces 34A and 34B that are in contact with the first portion 26 are appropriately changed according to the size and shape of the first portion 26, there may be cases where the irregular shape of the constant pattern is not configured. Therefore, the positions of the connecting ends 43A and 43B are also changed as appropriate, and may not match.

  With such a configuration, the first portion 26 of the conductor pattern 6C has the end surface 31 on the main surface 12b side in the stacking direction, the circumferential surfaces 32A and 32B, and the circumferential surfaces 33A and 33B in the width direction. The second portion 27 of the conductor pattern 6C includes an end surface 39 on the main surface 12a side in the stacking direction, and circumferential surfaces 34A to 38A and 34B to 38B in the width direction. Among these, the circumferential surfaces 35A, 36A, 37A, and 38A constitute the side surface 27A of the second portion 27. Further, the peripheral surfaces 35B, 36B, 37B, and 38B constitute a side surface 27B of the second portion 27. The side surfaces 27 </ b> A and 27 </ b> B of the second portion 27 are constituted by peripheral surfaces that form an uneven shape with the same pattern by the internal electrode layers 22, 23, and 24 that constitute the second portion 27. The peripheral surfaces 34A and 34B are removed from the side surfaces 27A and 27B. This is because the shapes of the peripheral surfaces 34A and 34B are appropriately changed according to the size and shape of the first portion 26, and therefore, unlike the peripheral surfaces of the other second portions 27, the concave / convex shape of the same pattern may not be formed. .

  In FIG. 5, a region overlapping with the side surface 27 </ b> A when viewed from the stacking direction is indicated by WA. A region overlapping with the side surface 27B when viewed from the stacking direction is indicated by WB. In these regions, tensile stress is likely to occur between the internal electrode layer and the insulator layer by repeated drying and shrinkage during manufacturing. Therefore, these areas will be described as stress concentration areas WA and WB. Outer boundary positions in the width direction of the stress concentration regions WA and WB are defined by the connecting ends 44A, 46A and 48A and the connecting ends 44B, 46B and 48B. Inner boundary positions in the width direction of the stress concentration regions WA and WB are defined by the connecting ends 45A and 47A and the connecting ends 45B and 47B.

  The first internal electrode layer 21 constituting the first portion 26 is formed in a shape different from the internal electrode layers 22, 23, 24 related to the second portion 27, or is arranged at a different position. In the present embodiment, the multilayer body 12 is configured to enter the inner side in the width direction with respect to the peripheral surfaces 32 </ b> A and 32 </ b> B of the first internal electrode layer 21. Thereby, the end in the width direction of the end surface 31 does not overlap the side surfaces 27A and 27B when viewed from the stacking direction. Specifically, the connecting end 41A, which is the end of the end surface 31 in the width direction, is disposed at a position that does not overlap with the side surfaces 27A and 27B when viewed from the stacking direction. That is, the connecting end 41A is disposed at a place other than the stress concentration areas WA and WB. Further, the connecting end 41B, which is the end of the end surface 31 in the width direction, is disposed at a position that does not overlap the side surfaces 27A and 27B when viewed from the stacking direction. That is, the connecting end 41B is disposed at a place other than the stress concentration areas WA and WB. In the present embodiment, the connection end 41A is disposed on the inner side in the width direction than the stress concentration region WA, and the connection end 41B is disposed on the inner side in the width direction than the stress concentration region WB.

  The conductor patterns C1 to C12 and the lead conductors D1 and D2 described above can be formed using a metal material such as Ag, for example. The conductor patterns C1 and C12 and the lead conductors D1 and D2 can be set to have a thickness of about 10 μm to 25 μm, and the conductor patterns C1 and C12 can be set to have a width of about 200 μm to 300 μm. can do.

(Manufacturing method of multilayer inductor)
Next, with reference to FIG. 6, a method for manufacturing the multilayer inductor 10 according to the present embodiment will be described. FIG. 6 shows only a part of the magnetic green sheet GS1 or nonmagnetic green sheet GS2 described later, but a conductive coating film described later on the magnetic green sheet GS1 or nonmagnetic green sheet GS2. The steps of forming H1 to H4 and magnetic coating films I1 to I4 are common.

  First, a magnetic slurry, a non-magnetic slurry, a conductor paste, and a connecting conductor paste are prepared. Specifically, the magnetic slurry is, for example, a magnetic powder such as Ni-Cu-Zn ferrite powder, Cu-Zn ferrite powder or Ni-Cu-Zn-Mg ferrite powder is kneaded together with a binder and a solvent. It is obtained by doing. The nonmagnetic material slurry is obtained, for example, by kneading nonmagnetic material powder such as Cu—Zn-based nonmagnetic ferrite powder together with a binder and a solvent. The conductor paste and the connecting conductor paste are prepared, for example, by blending a conductor powder together with a binder and an organic solvent at a predetermined ratio and then kneading. As the conductor powder, Ag, an Ag alloy, Cu, Cu alloy, or the like can be usually used, but it is more preferable to use Ag having a low resistivity. In addition, a three-roll, a homogenizer, a sand mill, etc. can be used for kneading | mixing. Moreover, in order to make the shrinkage ratio after firing of the conductor paste for connection lower than the shrinkage ratio after firing of the conductor paste, for example, the type and amount of the binder and the solvent are changed between the conductor paste and the conductor paste for connection. Yes.

  Subsequently, for example, using a doctor blade method or a printing method, the magnetic material slurry is applied onto a support such as a PET film to form the magnetic material green sheet GS1 (see FIG. 6) to be the magnetic material layers A1 to A12. . Further, for example, by using a doctor blade method or a printing method, a nonmagnetic slurry is applied on a support such as a PET film, and a nonmagnetic green sheet GS2 (see FIG. 6) that becomes the nonmagnetic layers B1 and B2 is obtained. Form. The thickness of the magnetic green sheet GS1 and the non-magnetic green sheet GS2 can be set to about 10 μm to 30 μm, for example. Then, through holes that penetrate the magnetic green sheet GS1 and the non-magnetic green sheet GS2 in the thickness direction are formed at predetermined positions by laser processing or the like, and a conductor paste is filled in the through holes.

  Subsequently, a conductive paste is applied in a predetermined pattern on the magnetic green sheet GS1 to be the magnetic layer A2, and dried at about 40 ° C. to 80 ° C. for less than 1 hour, whereby the conductive pattern C1 and the lead conductor D1 A band-shaped conductive coating film is formed. Similarly, a conductive paste is applied in a predetermined pattern on the magnetic green sheet GS1 serving as the magnetic layer A11 and dried to form a strip-shaped conductive coating film serving as the conductor pattern C12 and the lead conductor D2. The conductive coating film that becomes the conductor patterns C1, C12 and the lead conductors D1, D2 can have a thickness of about 10 μm to 25 μm. The conductive coating film that becomes the conductor patterns C1, C12 The width can be set to about 200 μm to 300 μm.

  Subsequently, on the magnetic green sheet GS1 to be the magnetic layers A3 to A10 and on the nonmagnetic green sheet GS2 to be the nonmagnetic layers B1 and B2, the conductive coating film and the magnetic film to be the conductor patterns C2 to C11 Magnetic coating films to be F1 to F10 are formed.

  First, as shown in FIG. 6, a magnetic slurry is applied on the magnetic green sheet GS1 to be the magnetic layers A3 to A10 or on the nonmagnetic green sheet GS2 to be the nonmagnetic layers B1 and B2. The magnetic material slurry I1 is formed by applying a magnetic slurry so that an exposed portion R1 of the conductor pattern is formed, and drying at about 40 ° C. to 80 ° C. for less than 1 hour. The exposed portion R1 formed by the magnetic coating film I1 is formed along the shape of the conductor pattern to be formed, but the size in the width direction is smaller than the size in the width direction of the target conductor pattern. Is set. The step of forming the magnetic coating film I1 constitutes a part of the first part forming step of forming the first part 26. In addition, a 1st part formation process is a process of creating the shape of the 1st part before baking, and the baking process is not included.

  Next, a conductor paste is applied along the shape of the conductor pattern on the exposed portion R1 on the magnetic green sheet GS1 (or the nonmagnetic green sheet GS2) and the magnetic coating film I1, and 40 ° C. to 80 ° C. The belt-like conductive coating film H1 is formed by drying at a degree of less than 1 hour. The conductive coating film H1 is formed so as to cover the edge of the magnetic coating film I1 using printing plate making. The conductive coating film H1 constitutes the first internal electrode layer 21, that is, the first portion 26 after firing. Moreover, the process of forming this electrically conductive coating film H1 comprises a part of 1st part formation process which produces the shape of the 1st part 26. FIG.

  Next, the magnetic substance coating film I2 is formed by applying the magnetic substance slurry on the conductive coating film H1 and the magnetic substance coating film I1 and drying at about 40 ° C. to 80 ° C. for less than 1 hour. The magnetic coating film I2 covers the edge portion of the conductive coating film H1, and forms an exposed portion R2 so that the upper surface other than the edge portion of the conductive coating film H1 is exposed. A size W2 in the width direction of the exposed portion R2 is larger than a size W1 in the width direction of the exposed portion R1. The step of forming the magnetic coating film I2 constitutes a part of the second portion forming step of creating the shape of the second portion 27. In addition, a 2nd part formation process is a process of creating the shape of the 2nd part before baking, and does not include the baking process.

  Next, a conductor paste is applied along the shape of the conductor pattern on the exposed portion R2 of the conductive coating film H1 and the magnetic coating film I2, and dried at about 40 ° C. to 80 ° C. for less than 1 hour. A strip-shaped conductive coating film H2 is formed. The conductive coating film H2 is formed to cover the edge of the magnetic coating film I2 using the same printing plate making as that of the conductive coating film H1. This conductive coating film H2 constitutes the second internal electrode layer 22, that is, a part of the second portion 27 after firing. Moreover, the process of forming this electrically conductive coating film H2 comprises a part of 2nd part formation process which produces the shape of the 2nd part 27. FIG.

  Next, the magnetic substance coating film I3 is formed by applying a magnetic substance slurry on the conductive coating film H2 and the magnetic substance coating film I2 and drying at about 40 ° C. to 80 ° C. for less than 1 hour. The magnetic coating I3 covers the edge of the conductive coating H2, and forms an exposed portion R3 so that the upper surface other than the edge of the conductive coating H2 is exposed. The size W2 in the width direction of the exposed portion R3 is larger than the size W1 in the width direction of the exposed portion R1. The step of forming the magnetic coating film I3 constitutes a part of the second portion forming step of creating the shape of the second portion 27.

  Next, on the exposed portion R3 of the conductive coating film H2 and the magnetic coating film I3, a conductor paste is applied along the shape of the conductor pattern and dried at about 40 ° C. to 80 ° C. for less than 1 hour, A strip-shaped conductive coating film H3 is formed. The conductive coating H3 is formed to cover the edge of the magnetic coating I3 using the same printing plate making as that of the conductive coatings H1 and H2. The conductive coating film H3 constitutes a part of the third internal electrode layer 23, that is, the second portion 27 after firing. Moreover, the process of forming this electrically conductive coating film H3 comprises a part of 2nd part formation process which produces the shape of the 2nd part 27. FIG.

  Next, the magnetic substance coating film I4 is formed by apply | coating a magnetic substance slurry on the electrically conductive coating film H3 and the magnetic substance coating film I3, and drying for less than 1 hour at about 40 to 80 degreeC. The magnetic coating film I4 covers the edge portion of the conductive coating film H3 and forms an exposed portion R4 so that the upper surface other than the edge portion of the conductive coating film H3 is exposed. The size W2 in the width direction of the exposed portion R4 is larger than the size W1 in the width direction of the exposed portion R1. The step of forming the magnetic coating film I4 constitutes a part of the second portion forming step of creating the shape of the second portion 27.

  Next, on the exposed portion R4 of the conductive coating film H3 and the magnetic coating film I4, a conductor paste is applied along the shape of the conductor pattern, and dried at about 40 ° C. to 80 ° C. for less than 1 hour, A strip-shaped conductive coating film H4 is formed. The conductive coating film H4 is formed so as to cover the edge of the magnetic coating film I4 using the same printing plate making as that of the conductive coating films H1, H2, and H3. The conductive coating film H4 constitutes the internal electrode layer 24, that is, a part of the second portion 27 after firing. Moreover, the process of forming this electrically conductive coating film H4 comprises a part of 2nd part formation process which produces the shape of the 2nd part 27. FIG.

  At this time, the conductive coating films H2, H3, and H4 that are conductive coating films constituting the second portion 27 have side surfaces H27A and H27B that are in contact with any one of the magnetic coating films I3 and I4 in the width direction. The side surfaces H27A and H27B form a concavo-convex shape with a constant pattern. The peripheral surfaces 34A and 34B of the conductive coating film H2 do not correspond to the side surfaces H27A and H27B in this case because they may not constitute a certain pattern of irregularities depending on the shape of the first portion 26. The conductive coating film H1 constituting the first portion 26 has an end face H31 that is in contact with the magnetic green sheet GS1 (or the nonmagnetic green sheet GS2). At this time, the connecting ends H41A and H41B, which are ends in the width direction of the end face H31, do not overlap with the side faces H27A and H27B when viewed from the stacking direction.

  Subsequently, the conductive paste for connection is applied on the exposed surface of the conductive coating film H4 located at the uppermost position among the conductive coating films H1 to H4 so as to be hemispherical, and the temperature is about 40 ° C. to 80 ° C. for 1 hour. The conductive coating film for connection is formed by drying less than. This conductive conductive film for connection constitutes a through-hole conductor.

  Subsequently, the magnetic green sheets GS1 to be the magnetic layers A1 to A12 and the nonmagnetic green sheets GS2 to be the nonmagnetic layers B1 and B2 are stacked in the order shown in FIG. 2, and pressure is applied in the stacking direction. To form a green sheet laminate (not shown). At this time, the conductive film for connection is crushed by another green sheet adjacent in the stacking direction, and the conductive film for connection and the through hole of the other green sheet among the conductive film H1 in the other green sheet. The portion filled with is connected.

  Subsequently, the green sheet laminate is cut into units of chips, and then fired at about 850 ° C. to 900 ° C. for 10 hours or more to produce the laminate 12. For example, the length of the laminate 12 in the longitudinal direction after firing is approximately 2.5 mm, the width is approximately 2.0 mm, and the height is approximately 1.0 mm. Thus, the magnetic green sheet GS1 becomes each magnetic layer A1 to A12, the nonmagnetic green sheet GS2 becomes each nonmagnetic layer B1, B2, and the conductive coating H1 to H4 becomes each conductor pattern C2 to C11. The magnetic coating films I1 to I4 become the magnetic films F1 to F10, and the connection conductive coating films become the connection conductors G1 to G10. In addition, the shrinkage | contraction rate at the time of baking of an electrically conductive coating film is set to about 15%-25%, for example, and the shrinkage ratio at the time of baking of each green sheet GS1, GS2 and a magnetic body coating film is about 10%-about 20%. Is set to Further, since the conductive paste and the conductive paste for connection are different as described above, the shrinkage rate during firing of the conductive conductive film H5 for connection is smaller than the shrinkage rate during firing of the conductive paint film. Yes.

  Subsequently, external electrodes 14 and 16 are formed on the laminate 12. As a result, the multilayer inductor 10 is formed. The external electrodes 14 and 16 are baked at a predetermined temperature (for example, 700 to 800 ° C.) after transferring a conductor paste mainly composed of Ag, Cu, or Ni to both side surfaces of the laminate 12 in the longitudinal direction, It is formed by plating. For electroplating, for example, Cu, Ni and Sn can be used.

(Function)
The operations and effects of the multilayer inductor 10 and the manufacturing method thereof according to the present embodiment will be described with reference to FIGS. In the multilayer inductor 10 according to the present embodiment, the conductor patterns C2 to C11 are formed thick by laminating a plurality of internal electrode layers. As shown in FIG. 5, the conductor patterns C2 to C11 have a first portion 26 on one main surface 2b side in the stacking direction and a second portion 27 on the other main surface 2a side. The first portion 26 has the first internal electrode layer 21 and is a portion in contact with the magnetic layers A3 to A10 or the nonmagnetic layers B1 and B2 arranged between the other conductor patterns. The first portion 26 has an end surface 31 that contacts the stacked body 12 on the one main surface 2b side in the stacking direction. The end surface 31 is formed of the magnetic layers A3 to A10 or the nonmagnetic layers B1 and B2. It becomes the contact surface. Here, the second portion 27 has side surfaces 27A and 27B that are in contact with the multilayer body 12 in the width direction of the conductor patterns C2 to C11. In the side surfaces 27A and 27B, drying and shrinkage are performed between the internal electrode layers 22, 23, and 24 and the magnetic films F1 to F10 at the time of manufacturing. Since the second portion 27 is configured by laminating a plurality of internal electrode layers 22, 23, and 24, drying and shrinkage are repeatedly performed for each internal electrode layer 22, 23, and 24 at the time of manufacture. Therefore, since the internal electrode layers 22, 23, and 24 are formed in the same pattern, stress is easily concentrated in the stress concentration regions WA and WB that overlap the side surfaces 27A and 27B of the second portion 27 in the stacking direction. Moreover, since the connection ends 41A and 41B in the width direction of the end face 31 of the first portion 26 are also the boundary portions between the first internal electrode layer 21 and the magnetic layers A3 to A10 or the nonmagnetic layers B1 and B2, the stress is increased. It becomes easy to concentrate. For example, in the conductor pattern 100 shown in FIG. 7, the connecting ends 141A and 141B in the width direction on the end surface 131 of the first portion 126 overlap the stress concentration regions WA and WB by the side surfaces 127A and 127B of the second portion 127. Therefore, stress concentrates in the vicinity of the stress concentration regions WA and WB, and there is a possibility that a crack CR is generated in the magnetic layer A.

  However, in the multilayer inductor 10 according to the present embodiment, as shown in FIG. 5, the connecting ends 41 </ b> A and 41 </ b> B in the width direction of the end surface 31 of the first portion 26 are the side surfaces 27 </ b> A and 27 </ b> A of the second portion 27 when viewed from the stacking direction. It does not overlap with 27B. That is, the connecting ends 41A and 41B are arranged at positions other than the stress concentration areas WA and WB. That is, instead of the connection ends 41A and 41B of the first portion 26 where stress is likely to concentrate between the magnetic layers A3 to A10 or the nonmagnetic layers B1 and B2 and the side surfaces 27A and 27B, Body membranes F1-F10 are arranged. Therefore, the stress from the side surfaces 27A and 27B of the second portion 27 is dispersed and relaxed by the magnetic films F1 to F10. As described above, it is possible to prevent the magnetic layers A3 to A10 and the nonmagnetic layers B1 and B2 that are insulating layers between the conductor patterns from being cracked, and to improve the reliability of the multilayer inductor 10. .

  Further, in the method for manufacturing the multilayer inductor 10 according to the present embodiment, as shown in FIG. 6, the connecting ends H41A and H41B in the width direction of the end surface H31 of the conductive coating H1 constituting the first portion 26 are from the stacking direction. The conductive coating films H2, H3, and H4 do not overlap with the side surfaces H27A and H27B. That is, the connecting ends H41A and H41B are arranged at positions other than the stress concentration regions WA and WB. That is, when viewed from the stacking direction, between the green sheets GS1, GS2 and the side surfaces H27A, H27B of the conductive coatings H2, H3, H4, instead of the connecting ends H41A, H41B of the conductive coating H1 where stress is likely to concentrate. Thus, the magnetic coating film I1 is disposed. Therefore, the stress from the side surfaces H27A and H27B of the conductive coating films H2, H3 and H4 is dispersed and relaxed by the magnetic coating film I1. In addition, by firing in this way, after firing and the multilayer inductor 10 is completed, the stress from the side surfaces 27A and 27B of the second portion 27 is dispersed and relaxed by the magnetic films F1 to F10. . As described above, cracks are prevented from occurring in the magnetic layers A3 to A10, the nonmagnetic layers B1 and B2, or the green sheets GS1 and GS2, which are insulating layers between the conductor patterns, and the multilayer inductor 10 reliability can be improved.

  In the present embodiment, as shown in FIG. 5, each peripheral surface of the conductor patterns C2 to C11 is an uneven surface in which concave portions and convex portions are alternately arranged in the stacking direction. A part of the laminated body 12 has entered the concave portion of the peripheral surface. For this reason, the laminated body 12 is extremely difficult to peel off from the concavo-convex circumferential surfaces by a so-called anchor effect. As a result, even if the thickness of the conductor patterns C2 to C11 is large (20 μm or more), cracks are hardly generated in the portion of the multilayer body 12 located between adjacent conductor patterns in the stacking direction. ing. Therefore, the possibility that adjacent conductor patterns are short-circuited due to the migration phenomenon is greatly reduced.

  In the multilayer inductor 10 according to the present embodiment, the first portion 26 has peripheral surfaces 32A and 32B that are in contact with the multilayer body 12 in the width direction and connected to the end surface 31. The peripheral surfaces 32A and 32B are curved so as to enter the conductor pattern side, and the connecting ends 41A and 41B in the width direction of the end surface 31 are arranged on the inner side in the width direction than the side surfaces 27A and 27B. Such a first portion 26 is coated with a magnetic material on the green sheets GS1 and GS2 so that a narrow exposed portion R1 is formed before the conductive coating film H1 is formed on the green sheets GS1 and GS2. The film I1 is formed, and the conductive film H1 is formed thereon (see FIG. 6). In other words, the presence of the narrow exposed portion R1 allows the connection ends 41A and 41B of the first portion 26 to extend in the width direction from the side surfaces 27A and 27B of the second portion 27 regardless of the size and shape of the conductive coating film H1. It becomes possible to arrange inside. According to such a structure, even when a printing plate making of the same size as that used in the second portion 27 is used when forming the conductive coating film H1 for constituting the first portion 26, a desired shape is obtained. Can be obtained. Further, when the width of the first portion is larger than that of the second portion (see, for example, FIG. 9A), or when the position of the first portion in the width direction is shifted from the second portion (for example, In FIG. 8B, there is a possibility that the inner diameter of the coil becomes narrow and the magnetic path becomes narrow. However, since the connection ends 41A and 41B of the first portion 26 are disposed on the inner side in the width direction than the side surfaces 27A and 27B of the second portion 27, the characteristics of the coil L can be maintained. As described above, the structure according to the present invention can be applied without being restricted in coil design.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments.

  For example, the cross-sectional shape of the conductor pattern is not particularly limited as long as the end of the end surface of the first portion does not overlap the side surface of the second portion when viewed from the stacking direction, as shown in FIGS. 8, 9, and 10. Conductor patterns 200, 300, 400, 500, 600, and 700 may be employed. The conductor pattern 200 shown in FIG. 8A forms a magnetic coating film after a narrow conductive coating film is formed on a green sheet. The conductor pattern 200 has a first portion 226 constituted by the first internal electrode layer 221. The first internal electrode layer 221 is formed using a printing plate making smaller than the internal electrode layer constituting the second portion 227. Accordingly, the connecting ends 241A and 241B in the width direction of the end surface 231 of the first portion 226 are not overlapped with the side surfaces 227A and 227B of the second portion 227 when viewed from the stacking direction, and are disposed on the inner side in the width direction. That is, the connecting ends 241A and 241B are arranged on the inner side in the width direction than the stress concentration regions WA and WB. Note that the peripheral surfaces 232A and 232B that do not form a certain pattern of irregularities with the other peripheral surfaces are not included in the side surfaces 227A and 227B of the second portion 227.

  The conductor pattern 300 shown in FIG. 8B is configured by shifting the first internal electrode layer 321 constituting the first portion 326 in the width direction with respect to the internal electrode layer of the second portion 327. The first internal electrode layer 321 is formed using the same printing plate making as the internal electrode layer constituting the second portion 327. After the conductive coating film and magnetic coating film forming the first portion 326 are formed on the green sheet, the conductive coating film and magnetic coating film for forming the second portion 327 are formed at positions shifted in the width direction. Accordingly, the connecting end 341A in the width direction of the end surface 331 of the first portion 326 is not overlapped with the side surface 327A of the second portion 327 when viewed from the stacking direction, and is disposed on the inner side in the width direction. That is, the connecting end 341A is disposed on the inner side in the width direction than the stress concentration area WA. Further, the connecting end 341B in the width direction of the end surface 331 of the first portion 326 is not overlapped with the side surface 327B of the second portion 327 when viewed from the stacking direction, and is disposed on the outer side in the width direction. That is, the connecting end 341B is disposed on the outer side in the width direction than the stress concentration region WB. Note that the peripheral surfaces 332A and 332B that do not form a fixed pattern with the other peripheral surfaces are not included in the side surfaces 327A and 327B of the second portion 327.

  The conductor pattern 400 shown in FIG. 9A is configured by making the first internal electrode layer 421 constituting the first portion 426 larger in the width direction than the internal electrode layer of the second portion 427. The first internal electrode layer 421 is formed by using a printing plate larger than the internal electrode layer constituting the second portion 427. After the conductive coating film constituting the first portion 426 is formed on the green sheet, a magnetic coating film is formed. Accordingly, the connecting ends 441A and 441B in the width direction of the end surface 431 of the first portion 426 are not overlapped with the side surfaces 427A and 427B of the second portion 427 when viewed from the stacking direction, and are disposed on the outer side in the width direction. That is, the connecting ends 441A and 441B are arranged on the outer side in the width direction than the stress concentration regions WA and WB. The peripheral surfaces 432A and 432B are not included in the side surfaces 427A and 427B of the second portion 427 because the peripheral surfaces 432A and 432B may not form an irregular shape with a certain pattern with other peripheral surfaces.

  In the conductor pattern 500 shown in FIG. 9B, the side surfaces of the first portion 526 and the second portion 527 are parallel to the stacking direction and are formed in a planar shape. Further, the first internal electrode layer 521 constituting the first portion 526 is smaller in the width direction than the internal electrode layer constituting the second portion 527. Accordingly, the connecting ends 541A and 541B in the width direction of the end surface 531 of the first portion 526 are not overlapped with the side surfaces 527A and 527B of the second portion 527 when viewed from the stacking direction, and are arranged on the inner side in the width direction. That is, the connecting ends 541A and 541B are disposed on the inner side in the width direction than the stress concentration regions WA and WB.

  The conductor pattern 600 shown in FIG. 10A is configured in a planar shape with the side surfaces of the first portion 626 and the second portion 627 parallel to the stacking direction. The first internal electrode layer 621 constituting the first portion 626 is larger in the width direction than the internal electrode layer constituting the second portion 627. Accordingly, the connecting ends 641A and 641B in the width direction of the end surface 631 of the first portion 626 are not overlapped with the side surfaces 627A and 627B of the second portion 627 when viewed from the stacking direction, and are disposed on the outer side in the width direction. That is, the connection ends 641A and 641B are disposed on the outer side in the width direction than the stress concentration regions WA and WB. As described above, the side surface of the conductor pattern may be configured on a plane without forming an uneven shape.

  In the conductor pattern 700 shown in FIG. 10B, the side surfaces of the first portion 726 and the second portion 727 are parallel to the stacking direction and are formed in a planar shape. The conductor pattern 700 is configured by shifting the first internal electrode layer 721 constituting the first portion 726 in the width direction with respect to the internal electrode layer of the second portion 727. The first internal electrode layer 721 is formed using the same printing plate making as the internal electrode layer constituting the second portion 727. Accordingly, the connecting end 741A in the width direction of the end surface 731 of the first portion 726 is not overlapped with the side surface 727A of the second portion 727 when viewed from the stacking direction, and is disposed on the inner side in the width direction. That is, the connecting end 741A is disposed on the inner side in the width direction than the stress concentration region WA. Further, the connecting end 741B in the width direction of the end surface 731 of the first portion 726 does not overlap the side surface 727B of the second portion 727 when viewed from the stacking direction, and is disposed on the outer side in the width direction. That is, the connection end 741B is disposed on the outer side in the width direction than the stress concentration region WB.

  In the above-described embodiment, the laminate 12 is configured by the magnetic layers A1 to A12 and the nonmagnetic layers B1 and B2. However, the present invention is not limited to this, and the entire configuration may be configured by a magnetic material. May be made of a nonmagnetic material. However, from the viewpoint of further improving the DC superposition characteristics by suppressing the magnetic saturation and suppressing the decrease in the inductance value when a large current is passed, the magnetic layer A4 and the magnetic layer A4 are magnetically The laminated body 12 is preferably configured in such a manner that the nonmagnetic layer B1 is interposed between the magnetic layer A5 and the nonmagnetic layer B2 is interposed between the magnetic layer A7 and the magnetic layer A8. .

  Moreover, although the above-mentioned embodiment demonstrated the case where there were four internal electrode layers which comprise a conductor pattern, the number of internal electrode layers is not specifically limited. The first portion only needs to include at least the first internal electrode layer closest to the main surface 2b in the stacking direction (that is, the internal electrode layer that contacts the green sheets GS1 and GS2 at the time of manufacture). You may be comprised by the layer.

  Further, in the above-described embodiment and modification, the side surface of the second portion is an uneven surface with a tapered shape that is sharpened, or a completely flat surface, but is not particularly limited, and is a gentle uneven surface. There may be.

  In the above-described embodiment and modification, the internal electrode layers constituting the second portion are completely the same pattern, and the peripheral surfaces constituting the side surfaces of the second portion are completely overlapped in the stacking direction ( In other words, the position of the connecting end is completely coincident with the stacking direction). However, as long as the stress concentration can occur, it is not necessary to completely overlap. The positions of the peripheral surfaces constituting the side surface of the second portion may be shifted from each other due to an error in manufacturing.

  DESCRIPTION OF SYMBOLS 10 ... Multilayer inductor, 12 ... Multilayer body, 21,22,23,24 ... Internal electrode layer, 21,221,321,421,521,621,721 ... First internal electrode layer, 26,226,326,426 , 526, 626, 726 ... first part, 27, 227, 327, 427, 527, 627, 727 ... second part, 27A, 27B, 227A, 227B, 327A, 327B, 427A, 427B, 527A, 527B, 627A, 627B, 727A, 727B ... side face 31,231,331,431,531,631,731 ... end face, 41A, 41B, 241A, 241B, 341A, 341B, 441A, 441B, 541A, 541B, 641A, 641B, 741A, 741B ... Connection end (end), A1 to A12 ... Magnetic layer (insulator layer), B1, 2 ... nonmagnetic layer (insulator layer), C1 to C12 ... conductor pattern, F1 to F10 ... magnetic layer (insulator layer), H1 ... conductive coating (first conductive coating), H2 to H4 ... conductive Coating film (second conductive coating film), I1... Magnetic substance coating film (first insulator coating film), I2 to I4... Magnetic substance coating film (second insulator coating film).

Claims (4)

A laminate formed by laminating a plurality of insulator layers;
A multilayer inductor comprising a plurality of strip-shaped conductor patterns electrically connected to each other and a coil disposed inside the multilayer body,
The conductor pattern is configured by laminating a plurality of internal electrode layers in the stacking direction of the stacked body, a first portion disposed on one side in the stacking direction, and a second disposed on the other side in the stacking direction. And having a portion,
The first portion has at least a first internal electrode layer disposed on the most one side in the stacking direction among the plurality of internal electrode layers,
The second portion has a side surface in contact with the multilayer body in the width direction of the conductor pattern,
The first portion has an end surface that comes into contact with the stacked body on one side in the stacking direction;
The end in the width direction of the end surface does not overlap the side surface as viewed from the stacking direction ,
The first portion has a peripheral surface that is curved so as to project toward the laminate,
The second portion has a peripheral surface that is curved so as to enter the conductor pattern side,
The connecting end that connects the peripheral surface curved so as to protrude toward the laminate in the first portion and the peripheral surface curved so as to enter the conductor pattern side in the second portion is the end surface. The laminated inductor is characterized in that it does not overlap the end in the width direction when viewed from the lamination direction .   The multilayer inductor according to claim 1, wherein the side surface has an uneven shape. The first portion has a peripheral surface that is in contact with the laminated body in the width direction and connected to the end surface;
The peripheral surface connected to the end surface is curved so as to enter the conductor pattern side,
3. The multilayer inductor according to claim 1, wherein the end of the end surface in the width direction is disposed on the inner side in the width direction than the side surface. 4. A laminate formed by laminating a plurality of insulator layers;
A plurality of strip-shaped conductor patterns are configured to be electrically connected to each other, and a coil disposed inside the laminate,
The conductor pattern is configured by laminating a plurality of internal electrode layers in the stacking direction of the stacked body, a first portion disposed on one side in the stacking direction, and a second disposed on the other side in the stacking direction. A multilayer inductor having a portion,
On the insulator sheet constituting the insulator layer, by forming a first conductive coating film constituting the internal electrode layer in the first portion, and a first insulator coating film constituting the insulator layer, Forming the first portion;
Forming the second portion by forming a second conductive coating film constituting the internal electrode layer in the second portion and a second insulator coating film constituting the insulator layer. ,
The second conductive coating film has a side surface that contacts the second insulator coating film in the width direction of the conductor pattern,
The first conductive coating film has an end surface in contact with the insulator sheet,
The end in the width direction of the end surface does not overlap the side surface as viewed from the stacking direction ,
The first portion has a peripheral surface that is curved so as to project toward the laminate,
The second portion has a peripheral surface that is curved so as to enter the conductor pattern side,
The connecting end that connects the peripheral surface curved so as to protrude toward the laminate in the first portion and the peripheral surface curved so as to enter the conductor pattern side in the second portion is the end surface. A method of manufacturing a multilayer inductor, wherein the end of the multilayer inductor does not overlap with the end in the width direction when viewed from the stack direction .

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