Patent Application
20200234877
One aspect of the present invention relates to a method of manufacturing a laminated coil component.
Known laminated coil components are provided with laminates obtained by laminating a plurality of insulator layers and inductor conductors interposed between the insulator layers in a laminating direction (for example, Japanese Unexamined Patent Publication No. 2015-070172). A method of manufacturing the laminated coil component includes a step of laminating a plurality of green sheets provided with a conductor pattern to burn.
In the above-described manufacturing method, a plurality of green sheets is laminated in such a way that the conductor patterns overlap with one another when seen in the laminating direction. However, in some cases, lamination displacement occurs in which the conductor pattern is displaced in an orthogonal direction orthogonal to the laminating direction with respect to the conductor pattern adjacent in the laminating direction.
One aspect of the present invention provides a method of manufacturing a laminated coil component capable of inhibiting lamination displacement.
The inventors of the present invention have investigated and studied the method of manufacturing a laminated coil component capable of inhibiting the lamination displacement. As a result, the present inventors have found the following facts.
When green sheets provided with a conductor pattern are laminated, the conductor pattern is interposed between the green sheets to receive force in a laminating direction. As a result, the conductor pattern is crushed to have a shape expanded in an orthogonal direction. Specifically, the conductor pattern is thick in the laminating direction at the center in the orthogonal direction, and becomes thinner in the laminating direction as it is closer to an end in the orthogonal direction. The conductor pattern includes an inclined surface inclined from the center in the orthogonal direction toward the end. Due to this inclined surface, the conductor pattern is likely to be displaced in the orthogonal direction with respect to the conductor pattern adjacent in the laminating direction.
A method of manufacturing a laminated coil component according to one aspect of the present invention is a method of manufacturing a laminated coil component provided with a laminate obtained by laminating a coil conductor forming a spiral coil and an insulator layer. The method of manufacturing a laminated coil component includes a step of providing a conductor pattern configured to become a coil conductor on a green sheet configured to become an insulator layer, and a step of laminating a plurality of green sheets provided with the conductor pattern. The conductor pattern includes a pair of first side surfaces opposed to each other in an orthogonal direction orthogonal to a laminating direction of the green sheet. At the step of laminating a plurality of green sheets, a depression is formed on at least one of the pair of first side surfaces.
In the method of manufacturing a laminated coil component according to one aspect of the present invention, at least one of the pair of first side surfaces of the conductor pattern does not have a shape expanded in the orthogonal direction but has a shape with the depression at the step of laminating a plurality of green sheets. For this reason, in the conductor pattern, the above-described inclined surface is less likely to be formed between the center in the orthogonal direction and the end in the orthogonal direction formed of the first side surface on which the depression is formed. Therefore, it is possible to inhibit lamination displacement.
At the step of laminating a plurality of green sheets, the depression may be formed on each of the pair of first side surfaces. In this case, at the step of laminating a plurality of green sheets, each of the pair of first side surfaces of the conductor pattern does not have the shape expanded in the orthogonal direction but has the shape with the depression. Therefore, it is further difficult that the above-described inclined surface is formed between the center in the orthogonal direction and each end in the orthogonal direction formed of the first side surface. Therefore, it is possible to further inhibit the lamination displacement.
A method of manufacturing a laminated coil component according to one aspect of the present invention is a method of manufacturing a laminated coil component provided with a laminate obtained by laminating a coil conductor forming a spiral coil and an insulator layer. The method of manufacturing a laminated coil component includes a step of providing a conductor pattern having a trapezoidal cross-section and configured to become the coil conductor on a green sheet configured to become the insulator layer, and a step of laminating a plurality of green sheets provided with the conductor pattern.
In the method of manufacturing the laminated coil component according to one aspect of the present invention, the conductor pattern having the trapezoidal cross-section is interposed between the green sheets to be crushed at the step of laminating a plurality of green sheets. For example, when the conductor pattern having a semicircular cross-section is crushed, the conductor pattern is likely to have a shape expanded in the orthogonal direction. In contrast, when the conductor pattern having the trapezoidal cross-section is crushed, the conductor pattern is less likely to have the shape expanded in the orthogonal direction. Therefore, it is possible to inhibit lamination displacement.
The conductor pattern may also include a second side surface brought into contact with the green sheet at the step of providing the conductor pattern and a third side surface opposing to the second side surface. After the step of laminating the plurality of green sheets, the second side surface may be flatter than the third side surface. In this case, as compared with a case where the third side surface is depressed toward the second side surface and the second side surface is depressed toward the third side surface at the same level as or more than the third side surface, the conductor pattern is less likely to be thin, so that stress concentration in the conductor pattern may be inhibited.
Hereinafter, embodiments are described in detail with reference to the accompanying drawings. In the description, the same reference sign is used for the same elements or elements having the same function, and redundant descriptions are omitted.
A laminated coil component according to the embodiment is described with reference to
As illustrated in
The laminate 2 has a rectangular parallelepiped shape. An outer surface of the laminate 2 includes a pair of end faces 2a and 2b opposed to each other and four side surfaces 2c, 2d, 2e, and 2f extending in an opposing direction of the pair of end faces 2a and 2b in such a way that the pair of end faces 2a and 2b are connected to each other. The side surface 2d is defined as a surface opposed to another electronic device, for example, when the laminated coil component 1 is mounted on another electronic device not illustrated (for example, a circuit board or an electronic component).
The opposing direction of the end faces 2a and 2b, an opposing direction of the side surfaces 2c and 2d, and an opposing direction of the side surfaces 2e and 2f are substantially orthogonal to one another. The rectangular parallelepiped shape includes a rectangular parallelepiped shape in which a corner and a ridge line are chamfered, and a rectangular parallelepiped shape in which a corner and a ridge line are rounded.
The laminate 2 is obtained by laminating a plurality of insulator layers 11, a plurality of coil conductors 21 to 25, and a plurality of lead conductors 26 and 27. The insulator layers 11 are laminated in the opposing direction of the side surfaces 2c and 2d of the laminate 2. That is, a laminating direction of the insulator layers 11 coincides with the opposing direction of the side surfaces 2c and 2d of the laminate 2. Hereinafter, the opposing direction of the side surfaces 2c and 2d is also referred to as the “laminating direction”. Each insulator layer 11 has a substantially rectangular shape when seen in the laminating direction.
Each insulator layer 11 is formed of a sintered body of a ceramic green sheet containing, for example, a magnetic material (Ni—Cu—Zn ferrite material, Ni—Cu—Zn—Mg ferrite material, Ni—Cu ferrite material or the like). In the actual laminate 2, the insulator layers 11 are integrated to such an extent that boundaries between the layers cannot be visually recognized (refer to
The external electrode 4 is disposed on a side of the end face 2a of the laminate 2 and the external electrode 5 is disposed on a side of the end face 2b of the laminate 2. That is, the external electrodes 4 and 5 are located in such a way as to be separated from each other in the opposing direction of the pair of end faces 2a and 2b. Each of the external electrodes 4 and 5 contains a conductive material (for example, Ag, Pd or the like). Each of the external electrodes 4 and 5 is formed as a sintered body of conductive paste containing conductive metal powder (for example, Ag powder, Pd powder or the like) and glass frit. Electroplating is applied to each of the external electrodes 4 and 5, so that a plating layer is formed on the surface thereof. Ni, Sn or the like is used in electroplating, for example.
The external electrode 4 includes five electrode portions: an electrode portion 4a located on the end face 2a, an electrode portion 4b located on the side surface 2d, an electrode portion 4c located on the side surface 2c, an electrode portion 4d located on the side surface 2e, and an electrode portion 4e located on the side surface 2f. The electrode portion 4a covers an entire surface of the end face 2a. The electrode portion 4b covers a part of the side surface 2d. The electrode portion 4c covers a part of the side surface 2c. The electrode portion 4d covers a part of the side surface 2e. The electrode portion 4e covers a part of the side surface 2f. The five electrode portions 4a, 4b, 4c, 4d, and 4e are integrally formed.
The external electrode 5 includes five electrode portions: an electrode portion 5a located on the end face 2b, an electrode portion 5b located on the side surface 2d, an electrode portion 5c located on the side surface 2c, an electrode portion 5d located on the side surface 2e, and an electrode portion 5e located on the side surface 2f. The electrode portion 5a covers an entire surface of the end face 2b. The electrode portion 5b covers a part of the side surface 2d. The electrode portion 5c covers a part of the side surface 2c. The electrode portion 5d covers a part of the side surface 2e. The electrode portion 5e covers a part of the side surface 2f. The five electrode portions 5a, 5b, 5c, 5d, and 5e are integrally formed.
As illustrated in
The coil conductors 21 to 25 and the lead conductors 26 and 27 are disposed in such a way as to be separated from one another in the laminating direction. The insulator layer 11 is disposed between each of the coil conductors 21 to 25 and the lead conductors 26 and 27. The coil conductors 21 to 25 and the lead conductors 26 and 27 have substantially the same thicknesses in the laminating direction. The coil conductors 21 to 25 and the lead conductor 27 are disposed in such a way as to overlap with one another through the insulator layer 11 when seen in the laminating direction. That is, each of the coil conductors 21 to 25 and the lead conductor 27 is interposed between the two insulator layers 11 in the laminating direction. A length in the laminating direction (minimum length) of each insulator layer 11 disposed between each of the coil conductors 21 to 25 and the lead conductor 27 is, for example, shorter than or equal to the length (maximum length) in the laminating direction of each of the coil conductors 21 to 25 and the lead conductor 27.
Ends of the coil conductors 21 to 25 are connected to one another by means of through-hole conductors 12a to 12d. Specifically, an end T1 of the coil conductor 21 and an end T2 of the coil conductor 22 are connected to each other by means of the through-hole conductor 12a. An end T3 of the coil conductor 22 and an end T4 of the coil conductor 23 are connected to each other by means of the through-hole conductor 12b. An end T5 of the coil conductor 23 and an end T6 of the coil conductor 24 are connected to each other by the through-hole conductor 12c. An end T7 of the coil conductor 24 and an end T8 of the coil conductor 25 are connected to each other by the through-hole conductor 12d.
In this manner, since the ends T1 to T8 of the coil conductors 21 to 25 are connected to one another by means of the through-hole conductors 12a to 12d, a spiral coil 20 is formed in the laminate 2. That is, the laminated coil component 1 is provided with the coil 20 in the laminate 2. The coil 20 includes a plurality of coil conductors 21 to 25 separated from one another in the laminating direction and electrically connected to one another. The coil 20 has an axial center in the laminating direction.
The coil conductors 21 to 25 are disposed in this order in the laminating direction. The coil conductor 21 out of the coil conductors 21 to 25 is disposed in a position the closest to the side surface 2c of the laminate 2 in the laminating direction. An end E1 of the coil conductor 21 forms one end E1 of the coil 20. The coil conductor 25 out of the coil conductors 21 to 25 is disposed in a position the closest to the side surface 2d of the laminate 2 in the laminating direction. An end E2 of the coil conductor 25 forms the other end E2 of the coil 20.
The lead conductor 26 is disposed on a side closer to the side surface 2c of the laminate 2 in the laminating direction than the coil conductor 21. The lead conductor 26 and the coil conductor 21 are adjacent to each other in the laminating direction. An end T9 of the lead conductor 26 is connected to the end E1 of the coil conductor 21 by means of the through-hole conductor 12e. That is, the lead conductor 26 and the end E1 of the coil 20 are connected to each other by means of the through-hole conductor 12e.
An end 26a of the lead conductor 26 is exposed on the end face 2b of the laminate 2 to be connected to the electrode portion 5a of the external electrode 5 covering the end face 2b. That is, the lead conductor 26 and the external electrode 5 are connected to each other. Therefore, the end E1 of the coil 20 and the external electrode 5 are electrically connected to each other by means of the lead conductor 26 and the through-hole conductor 12e.
The lead conductor 27 is disposed on a side closer to the side surface 2d of the laminate 2 in the laminating direction than the coil conductor 25. The lead conductor 27 and the coil conductor 25 are adjacent to each other in the laminating direction. An end T10 of the lead conductor 27 is connected to the end E2 of the coil conductor 25 by means of the through-hole conductor 12f. That is, the lead conductor 27 and the end E2 of the coil 20 are connected to each other by means of the through-hole conductor 12f.
An end 27a of the lead conductor 27 is exposed on the end face 2a of the laminate 2 to be connected to the electrode portion 4a of the external electrode 4 covering the end face 2a. That is, the lead conductor 27 and the external electrode 4 are connected to each other. Therefore, the end E2 of the coil 20 and the external electrode 4 are electrically connected to each other by means of the lead conductor 27 and the through-hole conductor 12f.
Each of the coil conductors 21 to 25, each of the lead conductors 26 and 27, and each of the through-hole conductors 12a to 12f contains, for example, a conductive material (for example, Ag or Pd). Each of the coil conductors 21 to 25, each of the lead conductors 26 and 27, and each of the through-hole conductors 12a to 12f is formed as a sintered body of conductive paste containing conductive metal powder (for example, Ag powder or Pd powder). For example, metal oxide (TiO2, Al2O3, and ZrO2) may be contained in each of the coil conductors 21 to 25, each of the lead conductors 26 and 27, and each of the through-hole conductors 12a to 12f. In this case, each of the coil conductors 21 to 25, each of the lead conductors 26 and 27, and each of the through-hole conductors 12a to 12f is formed as a sintered body of the conductive paste containing the metal oxide described above. In this case, it is possible to decrease a shrinkage rate at the time of burning the conductive paste.
A method of manufacturing the laminated coil component 1 is next described with reference to
First, binder resin or the like is mixed with ferrite powder being a main component of the laminate 2 to prepare insulator slurry. The prepared insulator slurry is applied onto a base material (for example, a PET film or the like) by a doctor blade method to form an insulator green sheet 31 (refer to
Next, the through-hole on the insulator green sheet 31 is filled with first conductive paste. The first conductive paste is prepared by mixing the conductive metal powder, the binder resin and the like. Subsequently, as illustrated in
A cross-section of the conductor pattern 32 has a trapezoidal shape. The conductor pattern 32 includes a pair of side surfaces 32a and 32b opposing to each other in a width direction (direction along the main surface 31a), and a pair of side surfaces 32c and 32d opposing to each other in a height direction (direction orthogonal to the main surface 31a). The width direction corresponds to the orthogonal direction, and the height direction corresponds to the laminating direction. The side surface 32c is a surface brought into contact with the main surface 31a of the insulator green sheet 31 at a step of providing the conductor pattern 32. The pair of side surfaces 32c and 32d is substantially parallel to the main surface 31a. A width of the conductor pattern 32 is maximum at the side surface 32c and minimum at the side surface 32d, and gradually decreases from the side surface 32c toward the side surface 32d. An aspect ratio being a ratio of height (maximum height) to width (maximum width) of the cross-section of the conductor pattern 32 is not smaller than 0.5 and smaller than 1.0 or not smaller than 0.7 and smaller than 1.1, for example. The center in the width direction of the side surface 32c and the center in the width direction of the side surface 32d overlap with each other as seen in the height direction.
Next, the insulator green sheet 31 is laminated. Herein, a plurality of insulator green sheets 31 provided with the conductor pattern 32 is peeled off from the base material to be laminated, and pressurized in the laminating direction to form laminate green. At that time, the insulator green sheets 31 are laminated in such a way that the conductor patterns 32 are overlapped with one another when seen in the laminating direction. The conductor patterns 32 configured to become the coil conductors 21 to 25 and the lead conductor 27. At a step of laminating the insulator green sheets 31, the conductor pattern 32 is interposed between the insulator green sheets 31 and receives force in the laminating direction. Accordingly, as illustrated in
In a crushed state, an aspect ratio being a ratio of length (maximum length) in the laminating direction to length (maximum length) in the orthogonal direction of the cross-section of the conductor pattern 32 is, for example, not smaller than 0.2 and not larger than 0.3. At that time, a depression 32e is formed on at least one of the pair of side surfaces 32a and 32b. Herein, the depression 32e is formed on the side surface 32a. The depression 32e is depressed toward the side surface 32b. The side surface 32b has a shape in which the center in the laminating direction is protruded (expanded) in the orthogonal direction. The pair of side surfaces 32c and 32d is substantially parallel in the orthogonal direction.
Next, the laminate green is cut into chips of a predetermined size by a cutting machine to obtain a green chip. Next, after removing the binder resin contained in each part from the green chip, the green chip is burned. Thereby, the laminate 2 is obtained. The cross-sectional shape of each of the coil conductors 21 to 25 and the lead conductor 27 illustrated in
Next, a function effect of the laminated coil component 1 according to this embodiment is described while describing a comparative example with reference to
A method of manufacturing the laminated coil component according to the comparative example differs from the method of manufacturing the laminated coil component 1 according to the embodiment in terms of a shape of a conductor pattern 132, but coincides with the same in all other terms. In the comparative example, as illustrated in
When the insulator green sheets 31 provided with the conductor pattern 132 having such a shape on the main surface 31a are laminated, the conductor pattern 132 is crushed to have a shape expanding in the orthogonal direction as illustrated in
Due to such inclined surface 132f, the conductor pattern 132 is likely to be displaced in the orthogonal direction with respect to the adjacent conductor pattern 132. As a result, as illustrated in
In contrast, in the method of manufacturing the laminated coil component 1, the conductor pattern 32 having a trapezoidal cross-section is provided on the main surface 31a of the insulator green sheet 31. The conductor pattern 32 is interposed between the insulator green sheets 31 to be crushed at a step of laminating a plurality of insulator green sheets 31. Since the conductor pattern 32 having the trapezoidal cross-section is crushed in this manner, the conductor pattern 32 is less likely to have a shape expanded in the orthogonal direction.
In the conductor pattern 32, at least one of the pair of side surfaces 32a and 32b does not have a shape expanded in the orthogonal direction but has the shape with the depression 32e. For this reason, the above-described inclined surface 132f is less likely to be formed between the center in the orthogonal direction and the end in the orthogonal direction in the conductor pattern 32. As a result, as illustrated in
The present invention is not limited to the above-described embodiment, and various modifications may be made.
As illustrated in
The depressions 32e may be continuously formed in a length direction of the conductor pattern 32 or may be formed intermittently in the length direction of the conductor pattern 32. Two or more depressions 32e may be formed side by side in the laminating direction.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-197143 | Oct 2016 | JP | national |
This application is a divisional application of U.S. application Ser. No. 15/725,129, filed Oct. 4, 2017, the contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15725129 | Oct 2017 | US |
| Child | 16843228 | US |
