JP6132027B2 - Manufacturing method of multilayer inductor element and multilayer inductor element - Google Patents

Description

The present invention relates to a method for manufacturing a multilayer inductor element, and in particular, manufactures a plurality of multilayer inductor elements by separating a multilayer substrate in which a plurality of coil conductors are embedded and an outermost layer and an intermediate layer are nonmagnetic layers. Regarding the method.
The present invention also relates to a multilayer inductor element in which a plurality of magnetic ceramic layers and a plurality of nonmagnetic ceramic layers are laminated such that an outermost layer and an intermediate layer form a nonmagnetic layer, and a coil conductor is embedded.

  An example of background technology for separating a mother substrate into a plurality of multilayer inductor elements (= multilayer bodies) using a diamond scriber is disclosed in Patent Document 1. According to this background art, the two outermost layers and the intermediate layer constituting the mother substrate are made nonmagnetic layers, and a groove for singulation is formed in one outermost layer. The diamond scriber is pressed against the other outermost layer, thereby generating a crack that reaches the intermediate layer from the other outermost layer. When bending stress is applied to the mother substrate in this state, the mother substrate is broken so as to connect the crack and the groove, and the mother substrate is divided into a plurality of multilayer inductor elements. However, this background art assumes a multilayer inductor element that can be reduced in height and can handle a large current.

  On the other hand, multilayer inductors for industrial products or mobile phone base stations have a higher demand for higher reliability than low profile. Here, “high reliability” is a performance such as no short circuit due to ion migration even after long-term use, so the coil conductor is arranged on the inner side of the laminate so that external moisture does not enter. Such measures are taken.

JP 2013-115227 A

  However, if the coil conductor is arranged on the inner side of the laminated body, the thickness of the laminated body increases, and there is a region where no stress is applied due to the difference in linear expansion coefficient between the ceramic and the coil conductor (silver paste). Occur. In this region, since the direction in which the cracks run cannot be predicted, the cracks may be unexpectedly broken at the time of singulation and may be judged as defective in the appearance inspection.

Therefore, a main object of the present invention is to provide a method for manufacturing a multilayer inductor element and a multilayer inductor element capable of increasing the yield at the time of singulation.

A method for manufacturing a multilayer inductor element according to the present invention includes: a first preparation step of preparing a plurality of first ceramic sheets each having a plurality of coil conductor patterns printed thereon and each including a magnetic material; A second preparatory step of preparing a plurality of second ceramic sheets, and laminating and firing the plurality of first ceramic sheets and the plurality of second ceramic sheets to embed a plurality of coil conductors and to form an outermost layer and an intermediate layer. A manufacturing process for manufacturing a multilayer substrate in which a layer forms a nonmagnetic layer, a groove forming process for forming a cut groove in the outermost layer of the multilayer substrate so as to avoid a plurality of coil conductors when viewed from the stack direction, and along the cut groove by cutting the laminated board Te method of manufacturing a multilayer inductor element having a singulation step of fabricating a plurality of pieces, and each assigned to a plurality of pieces And third preparation step of preparing one or more third ceramic sheet multiple dummy conductor patterns Ru extending along the notch groove so as to surround is printed on each respective multiple coil conductors viewed from the stacking direction The laminating step further includes an insertion step of inserting one or more third ceramic sheets between the first ceramic sheet closest to the outermost layer and the second ceramic sheet forming the outermost layer. To do.

  Preferably, the third ceramic sheet includes a magnetic body.

  Preferably, the third preparation step includes a printing step of printing a plurality of dummy conductor patterns on each of the plurality of third ceramic sheets so that the distance to the cut groove is different between the sheets, and the insertion step approaches the outermost layer. The step of laminating a plurality of third ceramic sheets in the order in which the distance from the dummy conductor pattern to the cut groove is shortened.

  Preferably, there is further provided a hole forming step of forming a plurality of through holes in the second ceramic sheet forming the intermediate layer so as to overlap the cut grooves when viewed from the stacking direction.

More preferably, a filling step of filling the plurality of through holes with a magnetic paste is further provided.
The multilayer inductor element according to the present invention is a multilayer inductor element in which a plurality of magnetic ceramic layers and a plurality of nonmagnetic ceramic layers are laminated so that the outermost layer and the intermediate layer form a nonmagnetic layer, and a coil conductor is embedded. A dummy conductor pattern extending along the side surface so as to surround the coil conductor when viewed from the stacking direction is disposed between the magnetic ceramic layer closest to the outermost layer and the nonmagnetic ceramic layer forming the outermost layer. It is characterized by that.

  If the coil conductor is designed to be embedded inside the multilayer inductor element, it is possible to suppress the influence of moisture from the outside on the coil conductor. However, the laminated substrate manufactured in this way may be broken in an unexpected direction when separated.

  Based on this, a third ceramic sheet on which a plurality of dummy conductor patterns are printed is prepared. Each dummy conductor pattern extends along the cut groove, and the third ceramic sheet is inserted between the first ceramic sheet closest to the outermost layer and the second ceramic sheet forming the outermost layer.

  As a result, in addition to the stress due to the difference in expansion coefficient between the coil conductor pattern and the first ceramic sheet, the stress due to the difference in expansion coefficient between the dummy conductor pattern and the third ceramic sheet is generated. When these stresses are generated, cracks can be made uniform when the laminated substrate is divided into pieces along the cut grooves, and the yield at the time of dividing is improved.

  In addition, if the 3rd ceramic sheet is made into a sheet | seat containing a magnetic body, the difference in the stress between a 1st ceramic sheet and a 3rd ceramic sheet will be suppressed.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

It is an exploded view which shows the state which decomposed | disassembled the multilayer inductor element of this Example. (A) is a plan view showing an example of a ceramic layer SH0 forming a multilayer inductor element, (B) is a plan view showing an example of ceramic layers SH1 and SH2 forming a multilayer inductor element, (C ) Is a plan view showing an example of a ceramic layer SH3 forming a multilayer inductor element, and (D) is a plan view showing an example of a ceramic layer SH4 forming a multilayer inductor element. (A) is a plan view showing an example of a ceramic layer SH5 forming a multilayer inductor element, (B) is a plan view showing an example of a ceramic layer SH6 forming a multilayer inductor element, (C) It is a top view which shows an example of ceramic layer SH7 and SH8 which form a multilayer inductor element, (D) is a top view which shows an example of ceramic layer SH9 which forms a multilayer inductor element, (E) is a multilayer type It is a top view which shows an example of ceramic layer SH10 which forms an inductor element. It is a perspective view which shows the external appearance of the multilayer inductor element of this Example. FIG. 5 is a cross-sectional view of the multilayer inductor element taken along the line AA in FIG. 4. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH0, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH0. It is process drawing shown, (C) is process drawing which shows the other one part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH0. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH1 and SH2, (B) is another manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH1 and SH2. FIG. 6C is a process diagram illustrating another part of the manufacturing process of the sheet before firing corresponding to the ceramic layers SH1 and SH2. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH3, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH3. (C) is a process diagram showing another part of the manufacturing process of the sheet before firing corresponding to the ceramic layer SH3, (D) is a process diagram of the sheet before firing corresponding to the ceramic layer SH3 It is process drawing which shows a part of others of a manufacturing process. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH4, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH4. (C) is a process diagram showing another part of the manufacturing process of the sheet before firing corresponding to the ceramic layer SH4, (D) is a process diagram of the sheet before firing corresponding to the ceramic layer SH4 It is process drawing which shows a part of others of a manufacturing process. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH5, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH5. It is process drawing shown, (C) is a process drawing which shows the other one part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH5. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH6, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH6. (C) is a process diagram showing another part of the manufacturing process of the sheet before firing corresponding to the ceramic layer SH6, (D) is a process diagram of the sheet before firing corresponding to the ceramic layer SH6 It is process drawing which shows a part of others of a manufacturing process. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH7 and SH8, (B) is another manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH7 and SH8. (C) is a process diagram showing another part of the manufacturing process of the sheet before firing corresponding to the ceramic layers SH7 and SH8, and (D) is a process diagram showing the ceramic layers SH7 and SH8. It is process drawing which shows further another part of the manufacturing process of the sheet | seat before baking corresponding to this. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH9, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH9. It is process drawing shown, (C) is a process drawing which shows the other one part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH9. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH10, (B) is another part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH10. (C) is a process diagram showing another part of the manufacturing process of the sheet before firing corresponding to the ceramic layer SH10, (D) is a process diagram of the sheet before firing corresponding to the ceramic layer SH10 It is process drawing which shows a part of others of a manufacturing process. (A) is process drawing which shows a part of manufacturing process of a multilayer inductor element, (B) is process drawing which shows another part of manufacturing process of a multilayer inductor element, (C) is a multilayer type It is process drawing which shows the other part of manufacturing process of an inductor element. It is an exploded view which shows the state which decomposed | disassembled the multilayer inductor element of the other Example. It is a top view which shows an example of ceramic layer SH1 'and SH2' which form the multilayer inductor element of another Example. It is sectional drawing of the multilayer inductor element of another Example. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH1 'and SH2', (B) is the sheet | seat before baking corresponding to ceramic layer SH1 'and SH2'. It is process drawing which shows the other part of a manufacturing process, (C) is process drawing which shows the other part of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH1 'and SH2', (D) These are process drawings which show still another part of the manufacturing process of the sheet before firing corresponding to the ceramic layers SH1 ′ and SH2 ′. (A) is process drawing which shows a part of manufacturing process of the multilayer inductor element of another Example, (B) is a process which shows another part of the manufacturing process of the multilayer inductor element of another Example. FIG. 6C is a process diagram illustrating another part of the manufacturing process of the multilayer inductor element of another embodiment. It is an exploded view which shows the state which decomposed | disassembled the multilayer inductor element of the other Example. It is a top view which shows an example of ceramic layer SH5 'which forms the multilayer inductor element of another Example. It is sectional drawing of the multilayer inductor element of another Example. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH5 ', (B) is another one of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH5'. FIG. 4C is a process diagram showing another part of the manufacturing process of a sheet before firing corresponding to the ceramic layer SH5 ′, and FIG. 4D is a firing process corresponding to the ceramic layer SH5 ′. It is process drawing which shows further another part of the manufacturing process of a front sheet | seat, (E) is a process drawing which shows another part of manufacturing process of ceramic layer SH5 '. (A) is process drawing which shows a part of manufacturing process of the multilayer inductor element of another Example, (B) is a process which shows another part of the manufacturing process of the multilayer inductor element of another Example. FIG. 10C is a process diagram illustrating another part of the manufacturing process of the multilayer inductor element of the other examples. It is an exploded view which shows the state which decomposed | disassembled the multilayer inductor element of the other Example. It is a top view which shows an example of ceramic layer SH8 'which forms the multilayer inductor element of another Example. It is sectional drawing of the multilayer inductor element of another Example. (A) is process drawing which shows a part of manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH8 ', (B) is another one of the manufacturing process of the sheet | seat before baking corresponding to ceramic layer SH8'. FIG. 4C is a process diagram illustrating another part of the manufacturing process of the sheet before firing corresponding to the ceramic layer SH8 ′, and FIG. 4D is a process diagram corresponding to the ceramic layer SH8 ′. It is process drawing which shows a part of others of the manufacturing process of the front sheet | seat. (A) is process drawing which shows a part of manufacturing process of the multilayer inductor element of another Example, (B) is a process which shows another part of the manufacturing process of the multilayer inductor element of another Example. FIG. 10C is a process diagram illustrating another part of the manufacturing process of the multilayer inductor element of the other examples.

  Referring to FIG. 1, a multilayer inductor element 10 of this embodiment is used as an antenna element for wireless communication in the 13.56 MHz band, and ceramic layers SH0 to SH10 in which each main surface is laminated in a square shape. including. The main surfaces of the ceramic layers SH0 to SH10 have the same size, and are laminated in this order. The ceramic layers SH0, SH5 and SH10 include a non-magnetic material, while the remaining ceramic layers SH1 to SH4 and SH6 to SH9 include a magnetic material.

  The laminated body 12 is a rectangular parallelepiped, the magnetic layer 12a is formed by the ceramic layers SH1 to SH4, the magnetic layer 12b is formed by the ceramic layers SH6 to SH9, the nonmagnetic layer 12c is formed by the ceramic layer SH0, and the ceramic layer SH5 is formed. The nonmagnetic layer 12d is formed, and the nonmagnetic layer 12e is formed by the ceramic layer SH10.

  That is, the multilayer body 12 constituting the multilayer inductor element 10 has a multilayer structure in which the magnetic layer 12a is sandwiched between the nonmagnetic layers 12c and 12d and the magnetic layer 12b is sandwiched between the nonmagnetic layers 12d and 12e. Each side of the square forming the main surface (= upper surface or lower surface) of the stacked body 12 extends along the X axis or the Y axis, and the thickness of the stacked body 12 increases along the Z axis.

  Referring to FIG. 2A, via hole conductors VH0a and VH0b reaching the lower surface are formed on the upper surface of ceramic layer SH0. The via-hole conductor VH0a is provided at a position corresponding to the negative side end in the X-axis direction and the negative side end in the Y-axis direction, and the via-hole conductor VH0b is a positive side end in the X-axis direction and the positive side in the Y-axis direction. It is provided at a position corresponding to the end. Pad electrodes 14a and 14b are formed on the lower surface of the ceramic layer SH0. The pad electrode 14a is provided at a position covering the via hole conductor VH0a, and the pad electrode 14b is provided at a position covering the via hole conductor VH0b.

  Referring to FIG. 2B, via hole conductors VH1a and VH1b reaching the lower surface are formed on the upper surface of ceramic layer SH1. In addition, via hole conductors VH2a and VH2b reaching the lower surface are formed on the upper surface of the ceramic layer SH2.

  The via-hole conductors VH1a and VH1b are provided at positions that overlap with the via-hole conductors VH0a and VH0b when the ceramic layer SH1 is stacked on the ceramic layer SH0, respectively. Similarly, via-hole conductors VH2a and VH2b are provided at positions that overlap with via-hole conductors VH1a and VH1b when ceramic layer SH2 is laminated on ceramic layer SH1, respectively.

  Referring to FIG. 2C, via hole conductors VH3a and VH3b and a looped coil conductor pattern CP3 reaching the lower surface are formed on the upper surface of the ceramic layer SH3. The via-hole conductor VH3a is provided at a position overlapping the via-hole conductor VH2a when the ceramic layer SH3 is stacked on the ceramic layer SH2. The via-hole conductor VH3b is provided at a position that overlaps the via-hole conductor VH2b when the ceramic layer SH3 is stacked on the ceramic layer SH2.

  The loop forming the coil conductor pattern CP3 extends in the clockwise direction on the upper surface of the ceramic layer SH3, with the center position on the upper surface of the ceramic layer SH3 as the start end and the position between the start end and the via-hole conductor VH3a as the end.

  The coil conductor pattern CP3 first extends from the start end to the negative side in the X-axis direction, and bends to the positive side in the Y-axis direction before reaching the upper surface end of the ceramic layer SH3. The bent coil conductor pattern CP3 is further bent to the positive side in the X-axis direction before reaching the upper end of the ceramic layer SH3. The coil conductor pattern CP3 extending on the positive side in the X-axis direction is bent again on the negative side in the Y-axis direction in the vicinity of the via-hole conductor VH3b, and further on the negative side in the X-axis direction before reaching the upper end of the ceramic layer SH3. Bend. The bent coil conductor pattern CP3 then reaches the end.

  Referring to FIG. 2D, via hole conductors VH4a to VH4d and a looped coil conductor pattern CP4 reaching the lower surface are formed on the upper surface of the ceramic layer SH4. The via-hole conductors VH4a and VH4b are provided at positions that overlap with the via-hole conductors VH3a and VH3b, respectively, when the ceramic layer SH4 is stacked on the ceramic layer SH3. Further, the via-hole conductor VH4c is provided at the center position on the upper surface of the ceramic layer SH2. Furthermore, the via-hole conductor VH4d is provided at a position that overlaps the end of the coil conductor pattern CP3 when the ceramic layer SH4 is laminated on the ceramic layer SH3.

  The loop forming the coil conductor pattern CP4 starts from the position where the via-hole conductor VH4d is formed and ends at a position slightly shifted to the positive side in the X-axis direction from this position, and the upper surface of the ceramic layer SH4 is clockwise. Extend.

  The coil conductor pattern CP4 first extends from the start end to the positive side in the Y-axis direction, and bends to the positive side in the X-axis direction before reaching the upper end of the ceramic layer SH4. The bent coil conductor pattern CP4 is bent again on the negative side in the Y-axis direction in the vicinity of the via-hole conductor VH4b, and further bent on the negative side in the X-axis direction before reaching the upper end of the ceramic layer SH4. The bent coil conductor pattern CP4 then reaches the end.

  Referring to FIG. 3A, via hole conductors VH5a to VH5d reaching the lower surface are formed on the upper surface of ceramic layer SH5. The via-hole conductors VH5a and VH5b are provided at positions that overlap with the via-hole conductors VH4a and VH4b when the ceramic layer SH5 is stacked on the ceramic layer SH4, respectively. The via-hole conductor VH5c is provided at the center position on the upper surface of the ceramic layer SH5. Furthermore, the via-hole conductor VH5d is provided at a position that overlaps the end of the coil conductor pattern CP4 when the ceramic layer SH5 is laminated on the ceramic layer SH4.

  Referring to FIG. 3B, via hole conductors VH6a to VH6d and a looped coil conductor pattern CP6 reaching the lower surface are formed on the upper surface of the ceramic layer SH6. The via-hole conductors VH6a and VH6b are provided at positions that overlap with the via-hole conductors VH5a and VH5b when the ceramic layer SH6 is stacked on the ceramic layer SH5, respectively. The via-hole conductor VH6c is provided at the center position on the upper surface of the ceramic layer SH6. Furthermore, the via-hole conductor VH6d is provided at a position overlapping the via-hole conductor VH5d when the ceramic layer SH6 is stacked on the ceramic layer SH5.

  The loop forming the coil conductor pattern CP6 starts from the position where the via-hole conductor VH6d is formed and ends at a position slightly shifted to the positive side in the X-axis direction from this position, and the upper surface of the ceramic layer SH6 is clockwise. Extend.

  The coil conductor pattern CP6 first extends from the start end to the negative side in the X-axis direction, and bends to the positive side in the Y-axis direction before reaching the upper end of the ceramic layer SH6. The bent coil conductor pattern CP6 is further bent to the positive side in the X-axis direction before reaching the upper end of the ceramic layer SH6. The coil conductor pattern CP6 extending on the positive side in the X-axis direction is bent again on the negative side in the Y-axis direction in the vicinity of the via-hole conductor VH6b, and further on the negative side in the X-axis direction before reaching the upper end of the ceramic layer SH6. Bend. The bent coil conductor pattern CP6 then reaches the end.

  Referring to FIG. 3C, via hole conductors VH7a to VH7d and a dummy conductor pattern DP7 reaching the lower surface are formed on the upper surface of the ceramic layer SH7. The via-hole conductors VH7a and VH7b are provided at positions that overlap the via-hole conductors VH6a and VH6b when the ceramic layer SH7 is laminated on the ceramic layer SH6, respectively. The via-hole conductor VH7c is provided at the center position on the upper surface of the ceramic layer SH7. Furthermore, the via-hole conductor VH7d is provided at a position that overlaps the end of the coil conductor pattern CP6 when the ceramic layer SH7 is laminated on the ceramic layer SH6.

  Strictly speaking, the dummy conductor pattern DP7 includes four linear conductors LC7a to LC7d. The linear conductor LC7a extends along the Y axis at a position on the negative side in the X axis direction from the center of the upper surface of the ceramic layer SH7. The linear conductor LC7b extends along the X-axis at a position on the positive side in the Y-axis direction from the center of the upper surface of the ceramic layer SH7. The linear conductor LC7c extends along the Y axis at a position on the positive side in the X axis direction from the center of the upper surface of the ceramic layer SH7. The linear conductor LC7d extends along the X axis at a position on the negative side in the Y axis direction from the center of the upper surface of the ceramic layer SH7. When viewed from the stacking direction, the linear conductors LC7a to LC7d are all provided outside the coil conductor pattern CP6.

  Via hole conductors VH8a to VH8d and a dummy conductor pattern DP8 reaching the lower surface are formed on the upper surface of the ceramic layer SH8. The via-hole conductors VH8a to VH8d are provided at positions that overlap with the via-hole conductors VH7a to VH7d when the ceramic layer SH8 is stacked on the ceramic layer SH7, respectively.

  Strictly speaking, the dummy conductor pattern DP8 includes four linear conductors LC8a to LC8d. The linear conductor LC8a extends along the Y axis at a position on the negative side in the X axis direction from the center of the upper surface of the ceramic layer SH8. The linear conductor LC8b extends along the X axis at a position on the positive side in the Y axis direction from the center of the upper surface of the ceramic layer SH8. The linear conductor LC8c extends along the Y axis at a position on the positive side in the X axis direction from the center of the upper surface of the ceramic layer SH8. The linear conductor LC8d extends along the X axis at a position on the negative side in the Y axis direction from the center of the upper surface of the ceramic layer SH8. When viewed from the stacking direction, the linear conductors LC8a to LC8d overlap the linear conductors LC7a to LC7d.

  Referring to FIG. 3D, via hole conductors VH9a to VH9d reaching the lower surface are formed on the upper surface of the ceramic layer SH9. The via-hole conductors VH9a to VH9d are provided at positions that overlap with the via-hole conductors VH8a to VH8d when the ceramic layer SH9 is stacked on the ceramic layer SH8, respectively.

  Referring to FIG. 3E, via hole conductors VH10a to VH10d reaching the lower surface are formed on the upper surface of ceramic layer SH10. The via-hole conductors VH10a to VH10d are provided at positions that overlap with the via-hole conductors VH9a to VH9d when the ceramic layer SH10 is stacked on the ceramic layer SH9, respectively. Pad electrodes 16a and 16b are formed on the upper surface of the ceramic layer SH10. The pad electrode 16a is provided at a position covering the via hole conductor VH10c, and the pad electrode 16b is provided at a position covering the via hole conductor VH10d.

  Since the ceramic layers SH1 to SH10 are configured as described above, the coil conductor patterns CP3 to CP4 and CP6 and the via-hole conductors VH4c to VH10c and VH4d to VH10d are connected in a coil shape. A wound body is formed inside the laminate 12. Since the magnetic body exists inside and outside the wound body, the wound body functions as an inductor.

  Thus, the multilayer inductor element 10 has the appearance shown in FIG. A passive element such as a capacitor or a resistance element (not shown) is mounted on the upper surface of the ceramic layer SH10. These passive elements are connected to pad electrodes 16a and 16b and via-hole conductors VH10a and VH10b. Further, the AA cross section of the multilayer inductor element 10 has the structure shown in FIG.

  The ceramic sheets forming each of the ceramic layers SH0, SH5 and SH10 are made of non-magnetic (relative magnetic permeability: 1) ferrite and have a thermal expansion coefficient in the range of “8.5” to “9.0”. Indicates. The ceramic sheets forming the ceramic layers SH1 to SH4 and SH6 to SH9 are made of magnetic (relative magnetic permeability: 100 to 120) ferrite and have a thermal expansion coefficient of “9.0” to “10.0”. Indicates the range value. Further, the pad electrodes 14a to 14b, 16a to 16b, the coil conductor patterns CP1 to CP4, the via-hole conductors VH0a to VH10a, VH0b to VH10b, VH4c to VH10c, and VH4d to VH10d are made of silver and the thermal expansion coefficient is “20”. Indicates.

  The sheet before firing corresponding to the ceramic layer SH0 is produced in the manner shown in FIGS. 6 (A) to 6 (C). First, a ceramic sheet made of a nonmagnetic ferrite material is prepared as a mother sheet BS0 (see FIG. 6A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions. Each of the plurality of rectangles defined by the broken lines is defined as a “divided unit”.

  Next, through holes HL0a and HL0b are formed in the mother sheet BS0 for each divided unit (see FIG. 6B). When attention is paid to each divided unit, the through hole HL0a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL0b is the positive side end in the X axis direction. And provided at a position corresponding to the positive side end in the Y-axis direction. The through holes HL0a and HL0b are then filled with a conductive paste (see FIG. 6C). The conductive paste filled in the through hole HL0a forms the via hole conductor VH0a, and the conductive paste filled in the through hole HL0b forms the via hole conductor VH0b.

  The sheet before firing corresponding to the ceramic layer SH1 or SH2 is produced in the manner shown in FIGS. 7 (A) to 7 (C). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS1 or BS2 (see FIG. 7A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, the through holes HL1a to HL1b or the through holes HL2a to HL2b are formed in the mother sheet BS1 or BS2 for each divided unit (see FIG. 7B). When attention is paid to each divided unit, the through hole HL1a or HL2a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL1b or HL2b is provided in the X axis direction. It is provided at a position corresponding to the positive side end and the positive side end in the Y-axis direction. The through holes HL1a to HL1b or the through holes HL2a to HL2b are then filled with a conductive paste (see FIG. 7C).

  The conductive paste filled in the through hole HL1a forms a via hole conductor VH1a, and the conductive paste filled in the through hole HL1b forms a via hole conductor VH1b. The conductive paste filled in the through hole HL2a forms the via hole conductor VH2a, and the conductive paste filled in the through hole HL2b forms the via hole conductor VH2b.

  The sheet before firing corresponding to the ceramic layer SH3 is produced in the manner shown in FIGS. 8 (A) to 8 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS3 (see FIG. 8A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL3a and HL3b are formed in the mother sheet BS3 for each divided unit (see FIG. 8B). The through hole HL3a is provided at a position corresponding to the negative end in the X-axis direction and the negative end in the Y-axis direction, and the through-hole HL3b is a positive end in the X-axis direction and the positive side in the Y-axis direction. It is provided at a position corresponding to the end.

  The through holes HL3a and HL3b thus formed are filled with a conductive paste (see FIG. 8C). The conductive paste filled in the through hole HL3a forms a via hole conductor VH3a, and the conductive paste filled in the through hole HL3b forms a via hole conductor VH3b. When the filling is completed, a coil conductor pattern CP3 extending in a loop shape is formed on the upper surface of each divided unit by screen printing (see FIG. 8D).

  The unfired sheet corresponding to the ceramic layer SH4 is produced as shown in FIGS. 9 (A) to 9 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS4 (see FIG. 9A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL4a to HL4d are formed in the mother sheet BS4 for each divided unit (see FIG. 9B). The through hole HL4a is provided at a position corresponding to the negative end in the X axis direction and the negative end in the Y axis direction, and the through hole HL4b is a positive end in the X axis direction and the positive side in the Y axis direction. The through hole HL4c is provided at the center position at a position corresponding to the end. Further, the through hole HL4d is formed at a position corresponding to the terminal end of the coil conductor pattern CP3 produced as described above.

  The through holes HL4a to HL4d thus formed are filled with a conductive paste (see FIG. 9C). The conductive paste filled in the through hole HL4a forms the via hole conductor VH4a, and the conductive paste filled in the through hole HL4b forms the via hole conductor VH4b. The conductive paste filled in the through hole HL4c forms a via hole conductor VH4c, and the conductive paste filled in the through hole HL4d forms a via hole conductor VH4d. When the filling is completed, a coil conductor pattern CP4 extending in a loop shape is formed on the upper surface of each divided unit by screen printing (see FIG. 9D).

  The sheet before firing corresponding to the ceramic layer SH5 is produced in the manner shown in FIGS. 10 (A) to 10 (C). First, a ceramic sheet made of a nonmagnetic ferrite material is prepared as a mother sheet BS5 (see FIG. 10A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL5a to HL5d are formed in the mother sheet BS5 for each divided unit (see FIG. 10B). When attention is paid to each divided unit, the through hole HL5a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL5b is a positive side end in the X axis direction. In addition, the through hole HL5c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. Further, the through hole HL5d is formed at a position corresponding to the end of the coil conductor pattern CP4 produced in the above-described manner.

  The through holes HL5a to HL5d are then filled with a conductive paste (see FIG. 10C). The conductive paste filled in the through hole HL5a forms the via hole conductor VH5a, and the conductive paste filled in the through hole HL5b forms the via hole conductor VH5b. The conductive paste filled in the through hole HL5c forms a via hole conductor VH5c, and the conductive paste filled in the through hole HL5d forms a via hole conductor VH5d.

  The sheet before firing corresponding to the ceramic layer SH6 is produced in the manner shown in FIGS. 11 (A) to 11 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS6 (see FIG. 11A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, the through holes HL6a to HL6d are formed in the mother sheet BS6 for each divided unit (see FIG. 11B). When attention is paid to each divided unit, the through hole HL6a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL6b is a positive side end in the X axis direction. In addition, the through hole HL6c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. The through hole HL6d is formed at a position corresponding to the via-hole conductor VH5d produced as described above.

  The through holes HL6a to HL6d are then filled with a conductive paste (see FIG. 11C). The conductive paste filled in the through hole HL6a forms the via hole conductor VH6a, and the conductive paste filled in the through hole HL6b forms the via hole conductor VH6b. The conductive paste filled in the through hole HL6c forms the via hole conductor VH6c, and the conductive paste filled in the through hole HL6d forms the via hole conductor VH6d. When the filling is completed, a coil conductor pattern CP6 extending in a loop shape is formed on the upper surface of each divided unit by screen printing (see FIG. 11D).

  The sheet before firing corresponding to the ceramic layer SH7 or SH8 is produced in the manner shown in FIGS. 12 (A) to 12 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS7 or BS8 (see FIG. 12A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, the through holes HL7a to HL7d or the through holes HL8a to HL8d are formed in the mother sheet BS7 or BS8 for each divided unit (see FIG. 12B). When attention is paid to each divided unit, the through hole HL7a or HL8a is provided at a position corresponding to the negative side end in the X-axis direction and the negative side end in the Y-axis direction, and the through-hole HL7b or HL8b extends in the X-axis direction. The positive end is provided at a position corresponding to the positive end in the Y-axis direction, and the through hole HL7c or HL8c is provided at the center position. Further, the through hole HL7d or HL8d is formed at a position corresponding to the terminal end of the coil conductor pattern CP6 produced as described above.

  The through holes HL7a to HL7d or the through holes HL8a to HL8d are then filled with a conductive paste (see FIG. 12C). The conductive paste filled in the through hole HL7a or HL8a forms the via hole conductor VH7a or VH8a, and the conductive paste filled in the through hole HL7b or HL8b forms the via hole conductor VH7b or VH8b. The conductive paste filled in the through hole HL7c or HL8c forms the via hole conductor VH7c or VH8c, and the conductive paste filled in the through hole HL7d or HL8d forms the via hole conductor VH7d or VH8d. When the filling is completed, a dummy conductor pattern DP7 or DP8 is formed on the upper surface of each divided unit by screen printing (see FIG. 12D).

  The sheet before firing corresponding to the ceramic layer SH9 is produced in the manner shown in FIGS. 13 (A) to 13 (C). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS9 (see FIG. 13A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL9a to HL9d are formed in the mother sheet BS9 for each divided unit (see FIG. 13B). When attention is paid to each divided unit, the through hole HL9a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL9b is a positive side end in the X axis direction. In addition, the through hole HL9c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. The through hole HL9d is formed at a position corresponding to the via-hole conductor VH8d produced as described above.

  The through holes HL9a to HL9d are then filled with a conductive paste (see FIG. 13C). The conductive paste filled in the through hole HL9a forms the via hole conductor VH9a, and the conductive paste filled in the through hole HL9b forms the via hole conductor VH9b. The conductive paste filled in the through hole HL9c forms a via hole conductor VH9c, and the conductive paste filled in the through hole HL9d forms a via hole conductor VH9d.

  The sheet before firing corresponding to the ceramic layer SH10 is produced in the manner shown in FIGS. 14 (A) to 14 (D). First, a ceramic sheet made of a nonmagnetic ferrite material is prepared as a mother sheet BS10 (see FIG. 14A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL10a to HL10d are formed in the mother sheet BS10 for each divided unit (see FIG. 14B). When attention is paid to each divided unit, the through hole HL10a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL10b is a positive side end in the X axis direction. In addition, the through hole HL10c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. Further, the through hole HL10d is formed at a position corresponding to the via hole conductor VH9d manufactured in the above-described manner.

  The through holes HL10a to HL10d are then filled with a conductive paste (see FIG. 14C). The conductive paste filled in the through hole HL10a forms the via hole conductor VH10a, and the conductive paste filled in the through hole HL10b forms the via hole conductor VH10b. The conductive paste filled in the through hole HL10c forms the via hole conductor VH10c, and the conductive paste filled in the through hole HL10d forms the via hole conductor VH10d.

  When the via-hole conductors VH10a to VH10d are thus formed, the pad electrodes 16a and 16b are printed on the upper surface of the mother sheet BS10 (see FIG. 14D). The pad electrode 16a is formed at a position covering the via hole conductor VH10c, and the pad electrode 16b is formed at a position covering the via hole conductor VH10d.

  The unfired sheets created in the above-described manner based on the mother sheets BS0 to BS10 are laminated and pressure-bonded in this order. At this time, the stacking positions of the sheets are adjusted so that the broken lines assigned to the sheets overlap when viewed from the Z-axis direction. The mother sheets BS7 and BS8 on which the dummy conductor patterns DP7 and DP8 are respectively printed are inserted between the mother sheet BS6 on which the coil conductor pattern CP6 closest to the outermost layer is printed and the mother sheet BS10 that forms the outermost layer. The As a result, the multilayer substrate LB1 shown in FIG. The laminated substrate LB1 thus manufactured is then fired (see FIG. 15B).

  When firing is completed, a cut groove GR extending along a broken line assigned to each sheet is formed on the upper surface of the laminated substrate LB1 (= the surface facing the positive side in the Z-axis direction) (see FIG. 15B). . When the cut groove GR is formed, the laminated substrate LB1 is inverted in the vertical direction, and the pad electrodes 14a and 14b are formed on the upper surface of the laminated substrate LB1 for each divided unit. Although not appearing in FIG. 15C, the pad electrodes 14a and 14b are formed so as to cover the via-hole conductors VH0a and VH0b provided for each divided unit, respectively.

  Thereafter, the diamond scriber DS is pressed from the lower surface (= the surface facing the negative side in the Z-axis direction) of the multilayer substrate LB1 along the cut groove GR (see FIG. 15C). The tip of the crack formed thereby remains on the nonmagnetic mother sheet BS5 due to the difference in material. Thereafter, the multilayer substrate LB1 is bent in a direction in which cracks spread. The crack reaches the cut groove GR, and the multilayer substrate LB1 is separated into a plurality of multilayer inductor elements 10, 10,.

  As can be seen from the above description, the multilayer inductor element 10 is manufactured by the following steps. First, a magnetic mother sheet BS3 printed with coil conductor patterns CP3, CP3,..., A magnetic mother sheet BS4 printed with coil conductor patterns CP4, CP4,... And coil conductor patterns CP6, CP6,. A magnetic mother sheet BS6 is prepared (first preparation step), and nonmagnetic mother sheets BS0, BS5, and BS10 are prepared (second preparation step).

  Further, a magnetic mother sheet BS7 on which dummy conductor patterns DP7, DP7,... Are printed and a magnetic mother sheet BS8 on which dummy conductor patterns DP8, DP8,... Are printed are prepared (third preparation step).

  The prepared mother sheets BS0, BS3 to BS8, BS10 and the other mother sheets BS1 to BS2, BS9 are subjected to a series of processes of lamination, pressure bonding and firing, thereby producing a laminated substrate LB1 (production process). . A plurality of coil conductors are embedded in the manufactured multilayer substrate LB1, and the outermost layer and the intermediate layer of the multilayer substrate LB1 are nonmagnetic layers.

  A cut groove GR is formed in the outermost layer of the manufactured laminated substrate LB1 so as to avoid a plurality of coil conductors when viewed from the lamination direction (groove formation step). The multilayer substrate LB1 is cut along the cut groove GR, whereby a plurality of multilayer inductor elements 10, 10,... Are obtained.

  Here, both dummy conductor patterns DP7 and DP8 are printed on the mother sheets BS7 and BS8 so as to extend along the cut groove GR. The mother sheets BS7 and BS8 are inserted between the mother sheet BS6 on which the coil conductor pattern CP6 closest to the outermost layer is printed and the mother sheet BS10 forming the outermost layer (insertion step).

  If the coil conductor is designed to be embedded inside the multilayer inductor element 10, it is possible to suppress the influence of moisture from the outside on the coil conductor. However, the laminated substrate manufactured in this way may be broken in an unexpected direction when separated.

  Based on this, mother sheets BS7 and BS8 on which dummy conductor patterns DP7 and DP8 are respectively printed are prepared. The dummy conductor patterns DP7 and DP8 extend along the cut groove GR, and the mother sheets BS7 and BS8 are disposed between the mother sheet BS6 on which the coil conductor pattern CP6 closest to the outermost layer is printed and the mother sheet BS10 forming the outermost layer. Inserted.

  Thus, in addition to the stress caused by the difference in expansion coefficient between the coil conductor patterns CP3, CP4 and CP6 and the mother sheets BS3, BS4 and BS6, the expansion coefficient of the dummy conductor patterns DP7 and DP8 and the mother sheets BS7 and BS8 Stress due to the difference occurs. By generating these stresses, the cracks can be made uniform when the multilayer substrate LB1 is separated into pieces along the cut grooves GR, and the yield at the time of separation is improved.

  Further, when viewed from the stacking direction, each of the dummy conductor patterns DP7 and DP8 is provided outside the coil conductor patterns CP3, CP4, and CP6. Thereby, the dummy conductor patterns DP7 and DP8 do not greatly hinder the formation of the magnetic field by the coil conductor, and the Q value of the coil conductor is improved.

  Referring to FIG. 16, the multilayer inductor element 10 of another embodiment is the multilayer inductor element shown in FIG. 1 except that ceramic layers SH1 ′ and SH2 ′ are employed instead of the ceramic layers SH1 and SH2. 10 is the same as in FIG.

  Referring to FIG. 17, via hole conductors VH1a and VH1b reaching to the lower surface and dummy conductor pattern DP1 are formed on the upper surface of ceramic layer SH1 ′. In addition, via hole conductors VH2a and VH2b and a dummy conductor pattern DP2 reaching the lower surface are formed on the upper surface of the ceramic layer SH2.

  The via-hole conductors VH1a and VH1b are provided at positions that overlap with the via-hole conductors VH0a and VH0b when the ceramic layer SH1 ′ is stacked on the ceramic layer SH0, respectively. Similarly, via-hole conductors VH2a and VH2b are provided at positions that overlap with via-hole conductors VH1a and VH1b when ceramic layer SH2 ′ is laminated on ceramic layer SH1 ′, respectively.

  Strictly speaking, the dummy conductor pattern DP1 includes four linear conductors LC1a to LC1d. The linear conductor LC1a extends along the Y axis at a position on the negative side in the X axis direction from the center of the upper surface of the ceramic layer SH1. The linear conductor LC1b extends along the X axis at a position on the positive side in the Y axis direction from the center of the upper surface of the ceramic layer SH1. The linear conductor LC1c extends along the Y axis at a position on the positive side in the X axis direction from the center of the upper surface of the ceramic layer SH1. The linear conductor LC1d extends along the X axis at a position on the negative side in the Y axis direction from the center of the upper surface of the ceramic layer SH1. When viewed from the stacking direction, the linear conductors LC1a to LC1d are provided at positions overlapping the linear conductors LC7a to LC7d provided on the ceramic layer SH7, respectively.

  Strictly speaking, the dummy conductor pattern DP2 includes four linear conductors LC2a to LC2d. The linear conductor LC2a extends along the Y axis at a position on the negative side in the X axis direction from the center of the upper surface of the ceramic layer SH2. The linear conductor LC2b extends along the X axis at a position on the positive side in the Y axis direction from the center of the upper surface of the ceramic layer SH2. The linear conductor LC2c extends along the Y axis at a position on the positive side in the X axis direction from the center of the upper surface of the ceramic layer SH2. The linear conductor LC2d extends along the X axis at a position on the negative side in the Y axis direction from the center of the upper surface of the ceramic layer SH2. When viewed from the stacking direction, the linear conductors LC2a to LC2d are provided at positions overlapping the linear conductors LC1a to LC1d provided on the ceramic layer SH1 ′, respectively.

  The cross section of the multilayer inductor element 10 produced by laminating the ceramic layers SH0, SH1 ′, SH2 ′, SH3 to SH10 shown in FIG. 16 has the structure shown in FIG.

  The unfired sheet corresponding to the ceramic layer SH1 ′ or SH2 ′ is produced in the manner shown in FIGS. 19 (A) to 19 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS1 ′ or BS2 ′ (see FIG. 19A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, the through holes HL1a to HL1d or the through holes HL2a to HL2d are formed in the mother sheet BS1 ′ or BS2 ′ for each divided unit (see FIG. 19B). When attention is paid to each divided unit, the through hole HL1a or HL2a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL1b or HL2b is provided in the X axis direction. It is provided at a position corresponding to the positive side end and the positive side end in the Y-axis direction.

  The through holes HL1a to HL1b or the through holes HL2a to HL2b are then filled with a conductive paste (see FIG. 19C). The conductive paste filled in the through hole HL1a or HL2a forms the via hole conductor VH1a or VH2a, and the conductive paste filled in the through hole HL1b or HL2b forms the via hole conductor VH1b or VH2b. When the filling is completed, a dummy conductor pattern DP1 or DP2 is formed on the upper surface of each divided unit by screen printing (see FIG. 19D).

  The unfired sheets prepared in the above-described manner based on the mother sheets BS0, BS1 ′, BS2 ′, BS3 to BS10 are laminated and pressure-bonded in this order. At this time, the stacking positions of the sheets are adjusted so that the broken lines assigned to the sheets overlap when viewed from the Z-axis direction. As a result, the multilayer substrate LB1 shown in FIG. The laminated substrate LB1 thus manufactured is then fired (see FIG. 20B).

  When firing is completed, a cut groove GR extending along the broken line assigned to each sheet is formed on the upper surface of the laminated substrate LB1 (= the surface facing the positive side in the Z-axis direction) (see FIG. 20B). .

  When the cut groove GR is formed, the laminated substrate LB1 is inverted in the vertical direction, and the pad electrodes 14a and 14b are formed on the upper surface of the laminated substrate LB1 for each divided unit. Although not appearing in FIG. 20C, the pad electrodes 14a and 14b are formed so as to cover the via-hole conductors VH0a and VH0b provided for each divided unit, respectively.

  Thereafter, the diamond scriber DS is pressed from the lower surface (= the surface facing the negative side in the Z-axis direction) of the multilayer substrate LB1 along the cut groove GR (see FIG. 20C). The tip of the crack formed thereby remains on the nonmagnetic mother sheet BS5 due to the difference in material. Thereafter, the multilayer substrate LB1 is bent in a direction in which cracks spread. The crack reaches the cut groove GR, and the multilayer substrate LB1 is separated into a plurality of multilayer inductor elements 10, 10,.

  By providing the dummy conductor patterns DP2 and DP3 in addition to the dummy conductor patterns DP7 and DP8, it is possible to make the cracks uniform throughout the entire area from the starting point to the ending point of singulation.

  Referring to FIG. 21, the multilayer inductor element 10 of the other embodiments is the same as the multilayer inductor element 10 shown in FIG. 1 except that a ceramic layer SH5 ′ is employed instead of the ceramic layer SH5. Therefore, the duplicate description regarding the same configuration is omitted.

  Referring to FIG. 22, via hole conductors VH5a to VH5d reaching the lower surface are formed on the upper surface of the nonmagnetic ceramic layer SH5 ′. The via-hole conductors VH5a and VH5b are provided at positions that overlap with the via-hole conductors VH4a and VH4b when the ceramic layer SH5 ′ is stacked on the ceramic layer SH4, respectively. The via-hole conductor VH5c is provided at the center position on the upper surface of the ceramic layer SH5 ′. Furthermore, the via-hole conductor VH5d is provided at a position overlapping the via-hole conductor VH4d when the ceramic layer SH5 ′ is stacked on the ceramic layer SH4.

  Magnetic bodies MGa to MGd are provided on each side of the square forming the main surface of the ceramic layer SH5 ′. Specifically, the magnetic body MGa is provided at the center of the side extending along the Y axis on the negative side in the X axis direction, and the magnetic body MGb is provided at the center of the side extending along the X axis on the positive side in the Y axis direction. . The magnetic body MGc is provided at the center of the side extending along the X axis on the negative side in the Y-axis direction, and the magnetic body MGd is provided at the center of the side extending along the Y axis on the negative side in the X-axis direction.

  The cross section of the multilayer inductor element 10 produced by laminating the ceramic layers SH0 to SH4, SH5 ', and SH6 to SH10 shown in FIG. 21 has the structure shown in FIG.

  The sheet before firing corresponding to the ceramic layer SH5 ′ is produced in the manner shown in FIGS. 24 (A) to 24 (E). First, a ceramic sheet made of a nonmagnetic ferrite material is prepared as a mother sheet BS5 ′ (see FIG. 24A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL5a to HL5d are formed in the mother sheet BS5 ′ for each divided unit (see FIG. 24B). When attention is paid to each divided unit, the through hole HL5a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL5b is a positive side end in the X axis direction. In addition, the through hole HL5c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. The through hole HL5d is formed at a position corresponding to the end of the coil conductor pattern CP4 provided in the ceramic layer SH4.

  The through holes HL5a to HL5d are then filled with a conductive paste (see FIG. 24C). The conductive paste filled in the through hole HL5a forms the via hole conductor VH5a, and the conductive paste filled in the through hole HL5b forms the via hole conductor VH5b. The conductive paste filled in the through hole HL5c forms a via hole conductor VH5c, and the conductive paste filled in the through hole HL5d forms a via hole conductor VH5d.

  Subsequently, a rectangular through hole HL5e is formed at a position straddling a broken line extending in each of the X-axis direction and the Y-axis direction (see FIG. 24D). Strictly speaking, the through hole HL5e is provided at the center of each side forming the division unit. The through hole HL5e is then filled with a magnetic paste. The filled magnetic paste forms the above-described magnetic bodies MGa to MGd.

  The mother sheets BS0 to BS4, BS5 ′ and BS6 to BS10 created in the above-described manner are stacked and pressure-bonded in this order. At this time, the stacking positions of the sheets are adjusted so that the broken lines assigned to the sheets overlap when viewed from the Z-axis direction. As a result, the multilayer substrate LB1 shown in FIG. The laminated substrate LB1 thus manufactured is then fired (see FIG. 25B).

  When firing is completed, a cut groove GR extending along the broken line assigned to each sheet is formed on the upper surface of the laminated substrate LB1 (= the surface facing the positive side in the Z-axis direction) (see FIG. 25B). .

  When the cut groove GR is formed, the laminated substrate LB1 is inverted in the vertical direction, and the pad electrodes 14a and 14b are formed on the upper surface of the laminated substrate LB1 for each divided unit. Although not appearing in FIG. 25C, the pad electrodes 14a and 14b are formed so as to cover the via-hole conductors VH0a and VH0b provided for each divided unit, respectively.

  Thereafter, the diamond scriber DS is pressed from the lower surface (= the surface facing the negative side in the Z-axis direction) of the multilayer substrate LB1 along the cut groove GR (see FIG. 25C). The tip of the crack formed thereby remains on the nonmagnetic mother sheet BS5 ′ due to the difference in material. Thereafter, the multilayer substrate LB1 is bent in a direction in which cracks spread. The crack reaches the cut groove GR, and the multilayer substrate LB1 is separated into a plurality of multilayer inductor elements 10, 10,.

  Thus, the through hole HL5e is formed in the mother sheet BS5 ', and the through hole HL5e is filled with the magnetic paste. As a result, the crack formed by the diamond scriber DS easily reaches the cut groove GR when the laminated substrate LB1 is bent.

  Referring to FIG. 26, the multilayer inductor element 10 of still another embodiment is the same as the multilayer inductor element 10 shown in FIG. 1 except that a ceramic layer SH8 ′ is employed instead of the ceramic layer SH8. For this reason, redundant description of the same configuration is omitted.

  Referring to FIG. 27, via hole conductors VH8a to VH8d and a dummy conductor pattern DP8 ′ reaching the lower surface are formed on the upper surface of the ceramic layer SH8 ′. The via-hole conductors VH8a to VH8d are provided at positions that overlap with the via-hole conductors VH7a to VH7d when the ceramic layer SH8 ′ is stacked on the ceramic layer SH7, respectively.

  Strictly speaking, the dummy conductor pattern DP8 ′ includes four linear conductors LC8a ′ to LC8d ′. When viewed from the stacking direction, the linear conductor LC8a ′ extends along the Y axis at a position on the negative side in the X-axis direction from the linear conductor LC7a, and the linear conductor LC8b ′ is in the Y-axis direction from the linear conductor LC7b. The position on the positive side of is extended along the X axis. Further, the linear conductor LC8c ′ extends along the Y axis in the X axis direction from the linear conductor LC7c, and the linear conductor LC8d ′ is in the negative position in the Y axis direction from the linear conductor LC7d. Extending along the X-axis.

  The cross section of the multilayer inductor element 10 produced by laminating the ceramic layers SH0 to SH7, SH8 ', and SH9 to SH10 shown in FIG. 26 has the structure shown in FIG.

  The unfired sheet corresponding to the ceramic layer SH8 ′ is produced in the manner shown in FIGS. 29 (A) to 29 (D). First, a ceramic sheet made of a magnetic ferrite material is prepared as a mother sheet BS8 ′ (see FIG. 29A). Here, a plurality of broken lines extending in the X-axis direction and the Y-axis direction indicate cutout positions.

  Next, through holes HL8a to HL8d are formed in the mother sheet BS8 ′ for each divided unit (see FIG. 29B). When attention is paid to each divided unit, the through hole HL8a is provided at a position corresponding to the negative side end in the X axis direction and the negative side end in the Y axis direction, and the through hole HL8b is a positive side end in the X axis direction. In addition, the through hole HL8c is provided at the center position at a position corresponding to the positive side end in the Y-axis direction. The through hole HL8d is formed at a position corresponding to the via hole conductor VH7d provided in the ceramic layer SH7.

  The through holes HL8a to HL8d are then filled with a conductive paste (see FIG. 29C). The conductive paste filled in the through hole HL8a forms the via hole conductor VH8a, and the conductive paste filled in the through hole HL8b forms the via hole conductor VH8b. The conductive paste filled in the through hole HL8c forms the via hole conductor VH8c, and the conductive paste filled in the through hole HL8d forms the via hole conductor VH8d. When the filling is completed, a dummy conductor pattern DP8 ′ is formed on the upper surface of each divided unit by screen printing (see FIG. 29D).

  The unfired sheets prepared in the above-described manner based on the mother sheets BS0 to BS7, BS8 ′, and BS9 to BS10 are laminated and pressure-bonded in this order. At this time, the stacking positions of the sheets are adjusted so that the broken lines assigned to the sheets overlap when viewed from the Z-axis direction. In particular, the mother sheets BS7 and BS8 ′ are stacked in the order in which the distance from the dummy conductor patterns DP7 and DP8 ′ to the broken line is shortened as the outermost layer of the multilayer substrate LB1 is approached. Thereby, the multilayer substrate LB1 shown in FIG. The laminated substrate LB1 thus manufactured is then fired (see FIG. 30B).

  When firing is completed, a cut groove GR extending along a broken line assigned to each sheet is formed on the upper surface of the laminated substrate LB1 (= the surface facing the positive side in the Z-axis direction) (see FIG. 30B). . When the cut groove GR is formed, the laminated substrate LB1 is inverted in the vertical direction, and the pad electrodes 14a and 14b are formed on the upper surface of the laminated substrate LB1 for each divided unit. Although not appearing in FIG. 30C, pad electrodes 14a and 14b are formed to cover via-hole conductors VH0a and VH0b provided for each divided unit, respectively.

  Thereafter, the diamond scriber DS is pressed from the lower surface (= the surface facing the negative side in the Z-axis direction) of the multilayer substrate LB1 along the cut groove GR (see FIG. 30C). The tip of the crack formed thereby remains on the nonmagnetic mother sheet BS5 due to the difference in material. Thereafter, the multilayer substrate LB1 is bent in a direction in which cracks spread. The crack reaches the cut groove GR, and the multilayer substrate LB1 is separated into a plurality of multilayer inductor elements 10, 10,.

  As described above, the dummy conductor pattern DP8 ′ close to the upper surface of the multilayer substrate LB1 is formed outside the dummy conductor pattern DP7 far from the upper surface of the multilayer substrate LB1 when viewed from the stacking direction. As a result, even if the crack trajectory generated by bending the multilayer substrate LB1 is shifted in the middle, the shift is corrected by the dummy conductor pattern DP8 ′.

  In any of the above-described embodiments, the number of dummy conductor patterns formed on the upper surface side of the mother sheet BS5 is two. However, three or more layers of dummy conductor patterns may be formed on the upper surface side of the mother sheet BS5.

  In any of the above-described embodiments, the nonmagnetic layer is provided at the center in the thickness direction of the multilayer substrate LB1. However, the nonmagnetic layer may be shifted to the upper surface side or the lower surface side from the center in the thickness direction of the multilayer substrate LB1.

DESCRIPTION OF SYMBOLS 10 ... Multilayer type inductor element 12 ... Multilayer body 14a, 14b, 16a, 16b ... Pad electrode SH0-SH10, SH1 ', SH2', SH5 ', SH8' ... Ceramic layer BS0-BS10, BS1 ', BS2', BS5 ' , BS8 '... Mother sheet (ceramic sheet)
LB1 ... Multilayer substrate CP3 to CP4, CP6 ... Coil conductor pattern DP2 to DP3, DP7 to DP8, DP8 '... Dummy conductor pattern GR ... Cut groove

Claims (6)

A first preparation step of preparing a plurality of first ceramic sheets each having a plurality of coil conductor patterns printed thereon and each including a magnetic material;
A second preparation step of preparing a plurality of second ceramic sheets each including a non-magnetic material;
A production process of producing a laminated substrate in which a plurality of coil conductors are embedded and an outermost layer and an intermediate layer form a nonmagnetic layer by laminating and firing the plurality of first ceramic sheets and the plurality of second ceramic sheets. When,
A groove forming step of forming a cut groove in the outermost layer of the multilayer substrate so as to avoid the plurality of coil conductors as viewed from the lamination direction;
A singulation process for producing a plurality of pieces by cutting the laminated substrate along the cut grooves,
A method for manufacturing a multilayer inductor element comprising:
1 or 2 or more the plurality said pieces to said plurality of coil conductors are viewed from the respective assigned and the stacking direction so as to surround each cut number multiple of Ru extending along the groove of the dummy conductor pattern is printed on each A third preparation step of preparing a third ceramic sheet of
The laminating step includes an inserting step of inserting the one or more third ceramic sheets between a first ceramic sheet closest to the outermost layer and a second ceramic sheet forming the outermost layer. A method for manufacturing a multilayer inductor element.   The method for manufacturing a multilayer inductor element according to claim 1, wherein the third ceramic sheet includes a magnetic material. The third preparatory step includes a printing step of printing the plurality of dummy conductor patterns on each of the plurality of third ceramic sheets so that the distance to the cut groove is different between the sheets,
The inserting step is a step of stacking a plurality of third ceramic sheet in the order in which the distance to the notch groove is shortened from the dummy conductor patterns closer to the outermost layer, according to claim 1 or 2 stacked according Inductor element manufacturing method. The laminated mold according to any one of claims 1 to 3 , further comprising a hole forming step of forming a plurality of through holes in the second ceramic sheet forming the intermediate layer so as to overlap the cut grooves when viewed from the lamination direction. Inductor element manufacturing method. The method for manufacturing a multilayer inductor element according to claim 4 , further comprising a filling step of filling the plurality of through holes with a magnetic paste. A multilayer inductor element in which a plurality of magnetic ceramic layers and a plurality of nonmagnetic ceramic layers are laminated so that an outermost layer and an intermediate layer form a nonmagnetic layer, and a coil conductor is embedded,
A dummy conductor pattern extending along the side surface so as to surround the coil conductor when viewed from the stacking direction is disposed between the magnetic ceramic layer closest to the outermost layer and the nonmagnetic ceramic layer forming the outermost layer. A multilayer inductor element characterized by the above .

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