JP2004127966A - Inductive element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductive element which has a high Q value, is provided at a comparatively low manufacturing cost, and capable of solving the problem wherein a restriction or the like is imposed on the length of a conductor when through-holes are employed, and to provide its manufacturing method. <P>SOLUTION: The inductive element is manufactured by the use of a core board which is provided with a plurality of U-shaped conductors that are formed in lines both in a horizontal direction and a lateral direction on its surface as the open sides of the U-shaped conductors are made to face in one direction or a laminated core board composed of laminated core boards which are each equipped with plurality of ladder-like conductors that are disposed in an array and formed on their surfaces. The inductive element is provided with the U-shaped conductors 2a located inside a rectangular parallelopipedic insulator 1 cut out from the laminated core board. The inductive element is equipped with bridging conductors 2b which are formed by cutting out the laminated core board so as to connect the U-shaped conductors 2a together, and a helical coil is formed of the conductors 2a and 2b. The inductive element is equipped with insulating layers 5 which are formed on the cut surfaces so as to cover the bridging conductors 2b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention is used as an inductance element having a laminated structure, a common mode choke coil, a transformer, or the like, or configured in combination with another element, or incorporated in a module. The present invention relates to an inductive element and a manufacturing method thereof.
[0002]
[Prior art]
As an example of a conventional inductive element, there is an element in which a coil is formed in a spiral shape using a photolithography method on the front and back surfaces of a core substrate made of a composite material or a resin in which a functional material powder and a resin are mixed (for example, see Patent Document 1). .).
[0003]
Further, as another conventional example, as typified by a multilayer ceramic chip inductor, green sheets having a conductor pattern of 1/2 to 3/4 turn winding are multilayer-stacked, cut, and fired, so that the green sheets are stacked in the stacking direction. There is a helical coil wound up (for example, see Patent Document 2).
[0004]
Some inductive elements of this type use a composite material of ferrite powder and resin as an insulating base (see, for example, Patent Documents 3 and 4).
[0005]
[Patent Document 1]
Japanese Patent No. 2714343 (page 3-4, FIGS. 3 and 5)
[Patent Document 2]
JP-A-11-103229 (page 4-5, FIG. 2)
[Patent Document 3]
JP-A-10-270255 (page 3-5, FIGS. 1 and 2)
[Patent Document 4]
JP-A-11-154611 (pages 4 to 6, FIGS. 1 and 2)
[Problems to be solved by the invention]
Among the conventional inductance elements, the one in which the coil is formed in a spiral shape uses the photolithography method, so that the pattern accuracy can be high, and the inductance value can be narrowed, but the coil shape is in a spiral shape. Therefore, there is a problem that the self resonance frequency and the Q value are low.
[0006]
On the other hand, the multilayer ceramic chip inductor having the helical coil formed by laminating the conductor patterns in the laminating direction as described above can have a relatively high Q value, but requires expensive PET sheets for each green sheet. It is necessary to prepare a base film consisting of:
[0007]
In order to solve such a problem, the present inventors have disclosed in Japanese Patent Application No. 2001-392940 the through-holes formed in two rows in a first layer made of a composite material or a resin in which a functional material powder and a resin are mixed. An inductive element has been proposed in which a hole is formed and a helical coil is formed by conductors communicating between different rows of through holes on the upper and lower surfaces of the first layer.
[0008]
With such a configuration, the conductor pattern can be realized by a formation process with high pattern accuracy, such as a photolithography method, and the conductor pattern is formed on the flat portion of the first layer (core substrate). Is improved, and variations in characteristics due to pattern shift in the case of multi-layer lamination are small, so that a narrow tolerance of electrical characteristics can be achieved. In addition, since the coil is formed by forming a planar conductor pattern instead of forming a helical coil in the laminating step, the coil can be formed in a short time, and the electrical characteristics can be adjusted to a narrow tolerance to adjust the characteristics. Since trimming is not required, cost can be reduced.
[0009]
However, in the inductive element of this prior application, it is necessary to form a through hole in the core substrate by using a laser or the like. If the hole has a depth of, for example, about 0.3 mm or more, it is difficult to form a through hole having a diameter of about 0.02 mm. In addition, there is a problem in that it is difficult to fill and form a through hole or a conductor having a uniform cross section in the through direction of the through hole. There is also a problem that it is difficult to form a through hole having a uniform shape.
[0010]
In view of the above-mentioned problems of the prior art, the present invention provides an inductive element that can obtain a high Q value, is relatively inexpensive in manufacturing cost, and can solve problems such as limitation of conductor length due to through holes. And a method for manufacturing the same.
[0011]
(1) An inductive element according to the present invention comprises a core substrate having a plurality of U-shaped conductors formed on the surface thereof, the opening side of which is oriented in one direction, and a core substrate having a plurality of U-shaped conductors. It is manufactured using a laminated core substrate obtained by laminating core substrates in which ladder-shaped conductors are arranged side by side,
A plurality of U-shaped conductors formed inside a rectangular parallelepiped insulator cut out from the laminated core substrate,
By cutting out the laminated core substrate, a bridge conductor formed on a cut surface formed by exposing the open end of the U-shaped conductor and connecting the U-shaped conductors,
An insulating layer formed on the cut surface to cover the bridge conductor,
A rectangular helical coil is formed by the U-shaped conductor and the bridge conductor.
[0012]
As described above, in the inductive element of the present invention, since the U-shaped conductor is formed on the same plane of the core substrate at one time, the restrictions on the conductor length and the cross-sectional area are relaxed, and a fine conductor pattern can be formed. Further, an inductive element can be provided which does not require an expensive auxiliary material such as a PET film, is more efficient than the case where a through hole is provided, is easy to manufacture, and is inexpensive. Further, since the coil is formed in a helical shape, the Q value can be increased.
[0013]
In addition, structurally, there is a degree of freedom in the manufacturing method, and an organic material or an inorganic material or a composite material of an organic and inorganic material can be used as a material to be used. .
[0014]
(2) The inductive element of the present invention is characterized in that two rectangular helical coils are formed by connecting the U-shaped conductors one by one with the bridge conductor.
[0015]
By forming the two helical coils and providing the terminal electrodes corresponding to the respective helical coils in this manner, it is possible to configure a choke coil and a transformer having the above characteristics.
[0016]
(3) In the inductive element according to the present invention, the U-shaped conductors of the respective layers are formed concentrically and multiplely, and the U-shaped conductors of the same size that are adjacent to each other in the stacking direction are connected by the bridge conductor. And, among the U-shaped conductors adjacent in the inward and outward directions, those having the same side end or the opposite end in the stacking direction are connected by a bridge conductor to form a multiple rectangular helical coil. .
[0017]
In this way, if multiple helical coils are concentrically formed, the number of turns can be increased, and an inductive element having a high inductance value can be obtained.
[0018]
(4) The inductive element of the present invention is characterized in that the insulator and the insulating layer are made of a resin or a composite material obtained by mixing a functional material powder with a resin.
[0019]
In the present invention, ceramic or the like can be used as the core substrate serving as the insulator. However, if the insulator and the insulating layer are made of a resin or a composite material obtained by mixing a functional material powder with a resin, a low dielectric constant can be obtained. With this configuration, a substrate having a high self-resonant frequency usable at high frequencies can be obtained, and processing can be facilitated. Further, by selecting the functional material powder, an inductive element having characteristics suitable for the purpose can be obtained.
[0020]
(5) In the inductive element of the present invention, it is preferable that the U-shaped conductor and the bridge conductor are formed by a photolithography method. By forming a helical coil with such a conductor, an inductive element having a low specific resistance and a high Q value can be provided.
[0021]
(6) In the method of manufacturing an inductive element of the present invention, a plurality of U-shaped conductors corresponding to three sides of a plurality of rectangular helical coils are formed on a surface of a core substrate such that the open ends of the U-shaped conductors face in the same direction. Formed vertically and horizontally,
A plurality of core substrates are laminated and integrated to form a laminated core substrate,
The laminated core substrate is cut so that an open end of the U-shaped conductor is exposed on a cut surface,
On the cut surface where the open end of the U-shaped conductor is exposed, by forming a bridge conductor connecting the open ends by a photolithographic method, a rectangular helical coil is formed,
Forming an insulating layer covering the bridge conductor on the cut surface on which the bridge conductor is formed;
The material is cut into individual chips to obtain an inductive element.
[0022]
According to such a method for manufacturing an inductive element according to the present invention, it is possible to relax the limitation on the conductor length and the conductor cross-sectional area, reduce the manufacturing cost, improve the Q characteristic, and obtain characteristics according to the application. .
[0023]
(7) Further, in the method of manufacturing an inductive element of the present invention, when the core substrates are stacked, the core substrates having the number of turns corresponding to the thickness of one inductive element are stacked and integrated,
By cutting the laminated core substrate so that the open ends of the coil conductors are exposed, a stick-shaped material containing a plurality of U-shaped conductors corresponding to a plurality of inductive elements is obtained, and then forming the bridge conductor Is performed.
[0024]
If a stick-shaped material incorporating such a U-shaped conductor is manufactured, three sides of each layer of the coil can be formed at a time, and an inductive element can be manufactured more efficiently and at a lower cost than in the case of through holes. .
[0025]
(8) In the method of manufacturing an inductive element according to the present invention, when the core substrates are stacked, the core substrates having the number of turns corresponding to the thickness of the plurality of inductive elements are stacked and integrated,
By cutting the laminated core substrate obtained in this manner so that the open ends of the coil conductors are exposed, a plate-like shape having a built-in U-shaped conductor having a width in the lamination direction corresponding to a plurality of inductive elements is built. After the material is obtained, the bridge conductor is formed.
[0026]
In this way, it is possible to manufacture more efficiently by obtaining a plate-shaped material in which U-shaped conductors for a plurality of inductive elements are embedded vertically and horizontally instead of a stick shape and forming a bridge conductor on the material. , And can reduce the manufacturing cost.
[0027]
(9) Further, the method of manufacturing an inductive element of the present invention is characterized in that conductor layers which are both end faces of terminal electrodes of the inductive element are provided on both end faces in the stacking direction of the laminated core substrate.
[0028]
In this manner, if the conductor layers that are the end surfaces of the terminal electrodes are provided in advance at both ends of the laminated core substrate, the terminal electrodes can be easily formed on the end surfaces of the terminal electrodes, and the inductive element can be soldered to the printed circuit board. When mounting, the inductive element can be stably fixed at a predetermined position due to the rise due to the surface tension of the solder on the end surface.
[0029]
(10) In the method of manufacturing an inductive element according to the present invention, a conductor layer serving as both end faces of terminal electrodes of the inductive element is provided at both ends of the laminated core substrate in the laminating direction and at a boundary between the inductive elements. It is characterized by the following.
[0030]
As described above, when a bridge conductor is formed after obtaining a plate-shaped material, a conductor layer is provided at a boundary between regions serving as inductive elements, and cut off at the center of the conductor layer portion to form a terminal electrode. An end face can be formed.
[0031]
(11) In the method of manufacturing an inductive element according to the present invention, when the laminated core substrate is cut, cutting is performed so that insulating layers are simultaneously formed around three sides of the U-shaped conductor.
[0032]
As described above, since the insulating layers on the three surfaces around the U-shaped conductor are formed by cutting the material, the subsequent process of applying the insulating layers on the three surfaces can be omitted, and the inductive element can be efficiently manufactured. Can be manufactured, and manufacturing costs can be reduced.
[0033]
(12) In the method for manufacturing an inductive element according to the present invention, a core substrate formed with a plurality of rows of ladder-shaped conductors is used as the core substrate instead of the core substrate formed with a U-shaped conductor,
By cutting the laminated core substrate in a direction perpendicular to the longitudinal direction of the ladder-like conductor, a substantially U-shaped conductor is obtained.
[0034]
Thus, even when a ladder-shaped conductor is used, a substantially U-shaped conductor can be obtained by cutting the laminated core substrate. However, in this case, a step of covering the opposite end of the U-shaped conductor with the insulating layer is indispensable.
[0035]
(13) In the method of manufacturing an inductive element according to the present invention, when the helical coil is formed, two helical coils per chip are connected by connecting one bridge conductor to the U-shaped conductor. Is formed.
[0036]
Thus, a common mode choke coil and a transformer can be obtained by obtaining two helical coils.
[0037]
(14) In the method of manufacturing an inductive element according to the present invention, a U-shaped conductor may be formed on each of the core substrates in a concentric multiple manner.
On the cut surface where the open ends of the U-shaped conductors of the laminated core substrate are exposed, adjacent ones of the U-shaped conductors of the same size that are adjacent in the laminating direction are connected by the bridge conductor, and the U-shaped conductors that are adjacent in the inner and outer directions. A plurality of rectangular helical coils are formed by connecting the ends of the helical coils by a bridge conductor.
[0038]
Thus, by forming multiple helical coils, an inductor having a high inductance value can be obtained.
[0039]
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a perspective view showing an embodiment of the inductive element according to the present invention, FIG. 1B is a sectional view showing the configuration of the coil, and FIG. FIG. 2 is a partial sectional view showing the terminal electrode structure, and FIG. 2 is a bottom view of the inductive element.
[0040]
In FIG. 1, 1 is an insulator, 2 is a coil formed in a rectangular helical shape, 3 is an electrode pad, 4 is a terminal electrode, and the terminal electrode 4 has an end face 4a formed on an end face. Reference numeral 5 denotes an insulating layer provided on a mounting surface on a printed circuit board (not shown).
[0041]
The helical coil 2 includes a U-shaped conductor 2a and a bridge conductor 2b connecting the open ends thereof. The U-shaped conductors 2a are arranged with their opening ends facing in the same direction, with a space therebetween, and arranged vertically and horizontally. The bridge conductor 2b is for connecting the open ends of the U-shaped conductors 2a, 2a in a bridge shape, and is formed by using a photolithography method.
[0042]
As a material of the insulator 1, a ceramic substrate or a core substrate made of a resin or a composite material obtained by mixing a functional material powder with a resin is used. The resin when the insulator 1 is made of a resin or a composite material, and the resin that forms the insulating layer 5 are thermosetting materials such as bismaleide triazine (BT resin), epoxy, polyimide, and vinylbenzyl, or A liquid crystal polymer or the like is used.
[0043]
Further, as a dielectric material to be mixed with these resins in powder form depending on the use, powder such as fused silica, glass, quartz, and alumina is used. In addition, by using a resin or a dielectric powder having a low dielectric constant, it is possible to obtain a resin having excellent high-frequency characteristics.
[0044]
Further, a composite material in which a magnetic material is mixed with a resin can be used. In this case, a powder of ferrite, iron oxide, metallic iron, permalloy, sendust or the like is used as the magnetic material.
[0045]
FIGS. 3 to 6 are views showing one embodiment of a method of manufacturing the inductive element shown in FIGS. In FIG. 3, reference numeral 1A denotes a core substrate, which is a ceramic substrate such as an alumina substrate, a resin substrate, or a composite material substrate obtained by mixing a resin with a functional material powder.
[0046]
In the present embodiment, the U-shaped conductors 2a are formed vertically and horizontally on the surface of the core substrate 1A using the photolithography method by the following steps. First, as shown in FIG. 3B, a copper base film 6 is formed on the entire surface of the core substrate 1A by electroless plating on the core substrate 1A shown in FIG. 3A. Next, as shown in FIGS. 3 (C) and 3 (D), a plurality of U-shaped resist removal portions 9 for forming a band-shaped conductor are formed by applying or pasting a resist 7 on the surface, exposing and removing the resist (photolithography method). To form These resist removal portions 9 are actually formed in several tens or more pairs, and the lengths of these resist removal portions 9 are formed to be several tens or more chips. However, for convenience of explanation, the number of pairs and length are small. It is drawn in.
[0047]
Next, as shown in FIG. 3E, a main plating layer 10 made of copper is formed on the resist-removed portion 9 by electrolytic plating. Thereafter, as shown in FIG. 3F, the resist 7 and the copper base film 6 are removed, and the U-shaped conductor 2a is formed by the remainder. FIG. 4A shows a core substrate 1A on which the U-shaped conductor 2a is formed.
[0048]
As shown in FIG. 4 (B), a plurality of core substrates 1A configured as described above are stacked to form a laminated core substrate 1B, and a conductor for forming an end surface 4a to be the terminal electrode 4 on an end surface thereof. The core substrate 1A in which the layer 11 is formed in a portion corresponding to the U-shaped conductor 2a is overlapped, and the core substrate 1A (the lowermost portion in the drawing) on which the conductor layer 11 is formed is also overlapped. Then, the plurality of core substrates 1A are integrated in a stacked state.
[0049]
Here, when the core substrate 1A is a thermosetting resin or a composite material thereof, the prepregs in a semi-cured state are laminated as they are and pressurized and heated to be fully cured to be integrated, or The U-shaped conductor 2a may be formed on the substrate, and the prepreg in a semi-cured state may be sandwiched between the substrates, pressurized, heated, and fully cured to be integrated. In the case of a thermoplastic resin or a composite material thereof, they are integrated by heat welding. In the case of a ceramic substrate, they are integrated by bonding.
[0050]
Thereafter, as shown in FIG. 4 (C), the material is cut along a cutting line 13 to obtain a stick-shaped material 14 as shown in FIG. 5 (A). The position of the cutting line 13 is such that the open end of the U-shaped conductor 2a is exposed on the cutting surface 15 and a part of the conductor 11 serving as the terminal electrode is cut as shown in FIG. The position and the cutting width W are set. Simultaneously with this cutting, insulating layers 1a and 1b (see FIG. 1B) are formed on the outer surface of the U-shaped conductor 2a.
[0051]
Next, as shown in FIG. 5 (B), by forming a bridge conductor 2b on the cut surface 15 and connecting adjacent ones of the open ends of the U-shaped conductor 2a, a helical coil is formed at the same time as forming the helical coil. An electrode pad 3 is formed.
[0052]
FIG. 6 is a view showing a process after the formation of the bridge conductor 2b. As shown in FIG. 6A, an insulating layer 5 covering the bridge conductor 2b and the electrode pad 3 is formed on the cut surface where the bridge conductor 2b is formed. Provide.
[0053]
The formation of the insulating layer 5 is performed by thermocompression bonding or bonding of a resin sheet or a sheet made of the composite material, or by applying an insulating paste made of such a material.
[0054]
6 (B) to 6 (G) show a step of forming the terminal electrode 4, and as shown in FIG. 6 (B), the insulating layer 5a on the electrode pad 3 is removed by a laser or the like. When the application of the insulating layer 5a is performed by screen printing or photolithography, the portion to be removed by the laser or the like may be formed in advance as a region without the insulating layer 5a.
[0055]
Next, as shown in FIG. 6C, the surface 5b of the insulating layer 5 is roughened by sandblasting or dissolution with a solvent to increase the adhesion strength by plating. Then, as shown in FIG. 6D, a base layer 4b to be the terminal electrode 4 is formed by plating or a conductive paste. Thereafter, as shown in FIG. 6E, a metal layer 4c of nickel, tin or the like for soldering the inductive element to the substrate is formed by electrolytic plating.
[0056]
6 (F) and 6 (G) show another example of a method of forming the terminal electrode 4. The conductor paste 4d is filled by printing or the like in a portion where the insulating layer 5 has been removed, and nickel for soldering is filled thereon. And a metal layer 4e of tin or the like is formed by electrolytic plating.
[0057]
Thereafter, the material 14 is cut at a portion corresponding to the cutting line 16 in FIG. 6 (H) to obtain individual chips.
[0058]
In the present embodiment, the semi-additive method is employed as the photolithography method for forming the U-shaped conductor 2a on the core substrate 1A. However, the additive method or pattern etching (subtract method) of a conductive film such as a metal foil is employed. The strip-shaped conductor 13 may be formed, and a sputtering or vapor deposition method can be used for forming the metal film. Further, a similar method can be employed for forming the bridge conductor 2b.
[0059]
In this inductive element, since the U-shaped conductor 2a is formed on the same plane on the core substrate 1A at a time, the positional accuracy of the coil pattern is improved. Further, an expensive PET film is not required as in the case of laminating green sheets, and it is more efficient than the case where a through hole is provided. . Further, since the U-shaped conductor 2a is formed at a time on the same plane of the core substrate 1A, the conductor length and the conductor cross-sectional area are not limited as in the case of a through hole, and the conductor has a uniform cross-sectional area. Can be formed, and the inductive element can be provided easily at a low cost. Further, since the coil is formed in a helical shape, the Q characteristic can be improved.
[0060]
In addition, structurally, there is a degree of freedom in the manufacturing method, and an organic material or an inorganic material or a composite material of an organic and inorganic material can be used as a material to be used. .
[0061]
If the insulator 1 and the insulating layer 5 are composed of a resin or a composite material in which a functional material powder is mixed with a resin to form a substrate having a low dielectric constant, a material having a high self-resonance frequency can be obtained. Processing becomes easy. Further, by selecting the functional material powder, an inductive element having characteristics suitable for the purpose can be obtained.
[0062]
Further, by forming the U-shaped conductor 2a by the photolithography method and forming the bridge conductor 2b by the photolithography method, it is possible to provide an inductive element having a lower specific resistance and a higher Q value.
[0063]
FIG. 7 shows another embodiment of the method of manufacturing an inductive element according to the present invention, in which an example is shown in which the laminated core substrates 1B are stacked via an adhesive layer 17 to constitute one collective material 19. This adhesive layer 17 is formed thicker than the thickness of the other core substrate 1A for cutting later. First, as shown by a cutting line 20 in FIG. 7A, a region 21 for forming a U-shaped conductor 2a to be an inductive element is formed vertically and horizontally as shown in a plan view in FIG. 7B. The obtained plate-shaped material 22 is obtained.
[0064]
Such a material 22 enables the formation of the bridge conductor 2b by the photolithography method, the formation of the insulating layer 5, and the formation of the terminal electrode 4 in a lump, so that the production can be performed more efficiently and the production cost can be reduced. After the formation of the bridge conductor 2b, the insulating layer 5, and the terminal electrode 4, the individual chips are cut by vertical and horizontal cutting lines 23 and 24.
[0065]
FIGS. 7C and 7D show another embodiment of the manufacturing method of the present invention, which is another example of the plate material. In the present embodiment, the conductors 11 to be the end faces 4a of the terminal electrodes 4 are formed and laminated on both end faces 19 of FIG. A slit 25 is provided in the portion of the adhesive layer 17 which is to be formed, and a base film 4a on the end surface of the terminal electrode 4 is provided in the portion by electroless plating and electrolytic plating as shown in FIG. By cutting along the line 24, an inductive element having the terminal electrode 4 having the end face 4a is obtained.
[0066]
In the present embodiment, the formation of the bridge conductor 2b by the photolithography method, the formation of the insulating layer 5, and the formation of the terminal electrode can be performed at the same time as described above, and the fixing strength is strong and stable at a predetermined position on the printed circuit board. An inductive element that can be fixed at a predetermined position can be provided.
[0067]
FIG. 8 shows another embodiment of the method of manufacturing the inductive element according to the present invention. In this embodiment, as shown in FIG. 8 (A), an inner circumferential U-shaped conductor 2c is formed on the surface of the core substrate 1A. A double U-shaped conductor composed of the outer U-shaped conductor 2d is arranged vertically and horizontally. As shown in FIG. 8B, the laminated core substrate obtained by laminating such a core substrate is arranged such that the open ends of the U-shaped conductors 2c and 2d are exposed to the cut surface, as shown in FIG. After cutting or after cutting, it is exposed by polishing. Then, as shown in FIG. 8 (B), the open ends of the inner peripheral U-shaped conductors 2c are connected to each other by a bridge conductor 2e by a photolithographic method to form an inner peripheral helical coil and one electrode pad 3a. .
[0068]
Next, as shown in FIG. 8C, one of the exposed portions at one end in the stacking direction of the inner circumferential side U-shaped conductor 2 c that is not connected by the bridge conductor 2 e and the outer circumferential side U-shaped conductor 2 d are connected to each other. The insulating layer 27 is covered together with the bridge conductor 2e except for the entire exposed portion and the electrode pad 3a. Then, the open end of the exposed U-shaped conductor of the inner peripheral U-shaped conductor 2c and one open end of the opposite one of the outer peripheral U-shaped conductor 2d are connected by the bridge conductor 2f. I do.
[0069]
Next, as shown in FIG. 8D, the exposed portion of the outer U-shaped conductor 2d is covered with the insulating layer 29 except for the portion connected by the bridge conductor 2f and the electrode pad 3a. . Then, a bridge conductor 2g connecting adjacent ones of the outer side U-shaped conductors 2d is formed, and at the same time, the other electrode pad 3b is formed. Then, the entire mounting surface is covered with the insulating layer 31. Thereafter, electrode formation and cutting are performed as described above.
[0070]
In this manner, by forming concentrically two or more helical coils, the number of turns can be increased, and an inductive element having a high inductance value can be obtained. In the present embodiment, among the U-shaped conductors adjacent in the inner and outer directions, the U-shaped conductors at the opposite ends in the laminating direction are connected to each other so that the magnetic flux generated by the inner and outer coils is in the same direction. Depending on how the bridge conductors adjacent to each other in the stacking direction are connected, U-shaped conductors at the same side ends may be connected in the stacking direction so that the magnetic fluxes generated by the inner and outer coils are in the same direction.
[0071]
FIG. 9A shows another embodiment of the inductive element of the present invention, and shows an inductive element configured as a common mode choke coil or a transformer. In the present embodiment, two rectangular helical coils are formed by dividing the U-shaped conductor 2a into the conductors 2b1 and 2b2 with respect to the U-shaped conductor 2a. 3c and 3d are electrode pads connected to both ends of one of the two helical coils, 3e and 3f are electrode pads connected to both ends of the other two helical coils, and 41 to 44 are these electrode pads 3c, respectively. To 3f.
[0072]
As described above, it is possible to form two helical coils by changing the connection structure by the bridge conductor between the U-shaped conductors 2a and 2a.
[0073]
Further, as shown in FIG. 9B, it is also possible to configure an inductive element array in which a plurality of helical coils are provided side by side on one chip.
[0074]
FIG. 10 is a plan view of a core substrate showing another embodiment of the method for manufacturing an inductive element of the present invention, in which conductors 33 formed on a core substrate 1A are formed in a shape in which ladders are juxtaposed. In this case, as shown by the cutting line 34, the vicinity of the portion corresponding to the step of the ladder is cut. As a result, a substantially U-shaped conductor is formed. In the case of this embodiment, it is necessary to form an insulating layer on the surface opposite to the open end of the U-shaped conductor.
[0075]
The inductive element according to the present invention is not only used as an independent element such as an inductance element or a transformer, but also in a form integrated with other elements such as a capacitor or a resistor, or incorporated in a module. It can be provided as provided for use.
[0076]
【The invention's effect】
According to the present invention, since the U-shaped conductor is formed on the same plane of the core substrate at one time, the restrictions on the conductor length and the sectional area are relaxed, and a fine conductor pattern can be formed. In addition, since an expensive auxiliary material such as a PET film is not required, and it can be manufactured more efficiently as compared with the case where a through hole is provided, an inductive element can be provided easily at a low cost. Further, since the coil is formed in a helical shape, the Q value can be increased.
[0077]
In addition, structurally, there is a degree of freedom in the manufacturing method, and an organic material or an inorganic material or a composite material of an organic and inorganic material can be used as a material to be used. .
[Brief description of the drawings]
1A is a perspective view showing an embodiment of an inductive element according to the present invention, FIG. 1B is a sectional view showing a configuration of a coil thereof, and FIG. 1C is a sectional view showing an electrode structure thereof. .
FIG. 2 is a bottom view of the inductive element of the present embodiment.
3A is a perspective view showing a core substrate as a raw material of the present embodiment, FIG. 3B is a side view showing a state in which a base film is formed on the core substrate by electroless plating, and FIG. Plan view showing a state in which a resist pattern is formed on a core substrate, (D) is an enlarged sectional view thereof, (E) and (F) are states in which a U-shaped conductor is formed by electrolytic plating, and thereafter, the resist and the base film are removed. It is sectional drawing which shows the state which carried out.
4A is a perspective view showing a core substrate on which a U-shaped conductor of the present embodiment is formed, FIG. 4B is an exploded perspective view showing a laminated structure thereof, and FIG. 4C is a perspective view showing a laminated state thereof. , (D) are plan views showing the cut portions.
FIG. 5A is a perspective view showing a stick-shaped material obtained by cutting in the present embodiment, and FIG. 5B is a perspective view showing a state in which a bridge conductor and an electrode pad are formed on the cut surface. is there.
FIG. 6A is a cross-sectional view showing a state in which an insulating layer is formed on a cut surface in this embodiment, FIGS. 6B to 6E are cross-sectional views showing an electrode forming step, and FIGS. () Is a cross-sectional view showing another example of the electrode forming process, and (H) is a bottom view showing a cut portion of each chip.
FIG. 7A is a perspective view of a laminated core substrate showing another embodiment of the method of manufacturing an inductive element of the present invention, FIG. 7B is a plan view showing a cut portion thereof, and FIG. FIG. 14 is a plan view of a material showing another embodiment of the method of manufacturing the inductive element, and FIG. 14D is a cross-sectional view showing a slit structure formed at the boundary of the inductive element.
FIG. 8A is a plan view of a core substrate showing another embodiment of the method for manufacturing an inductive element of the present invention, and FIGS. 8B to 8E show steps of forming a bridge conductor on the core substrate. It is a top view.
FIGS. 9A and 9B are perspective views showing another embodiment of the inductive element of the present invention.
FIG. 10 is a plan view of a core substrate showing another embodiment of the method for manufacturing an inductive element of the present invention.
[Explanation of symbols]
1: insulator, 1A: core substrate, 1B: laminated core substrate, 2: spiral coil, 2a to 2d: U-shaped conductor, 2e to 2g: bridge conductor, 3, 3a to 3f: electrode pad, 4: terminal electrode, 4a: end face portion, 4b: base layer, 4c, 4e: metal layer for soldering, 4d: conductor paste, 5: insulating layer, 6: base film, 7: resist, 9: resist removed portion, 10: main plating layer , 11: conductor layer, 13: cutting line, 14: stick-shaped material, 15: cut surface, 17: adhesive layer, 19: assembly material, 20: cutting line, 21: U-shaped conductor forming area, 22: plate-shaped material , 23, 24: cutting line, 25: slit, 27, 29, 31: insulating layer, 33: ladder-shaped conductor, 34: cutting line, 41 to 44: terminal electrode

Claims (14)

A core substrate on the surface of which a plurality of U-shaped conductors are formed vertically and horizontally with the opening side oriented in one direction, or a laminated core substrate on which a core substrate on which a plurality of ladder-like conductors are juxtaposed is laminated. Made using
A plurality of U-shaped conductors formed inside a rectangular parallelepiped insulator cut out from the laminated core substrate,
By cutting out the laminated core substrate, a bridge conductor formed on a cut surface formed by exposing the open end of the U-shaped conductor and connecting the U-shaped conductors,
An insulating layer formed on the cut surface to cover the bridge conductor,
An inductive element, wherein a rectangular helical coil is formed by the U-shaped conductor and the bridge conductor. The inductive element according to claim 1,
An inductive element wherein two rectangular helical coils are formed by connecting the U-shaped conductors one by one by the bridge conductor. The inductive element according to claim 1,
The U-shaped conductors of the respective layers are formed concentrically in multiples, and those adjacent in the stacking direction of the U-shaped conductors of the same size are connected by the bridge conductor, and the U-shaped conductors adjacent in the inside and outside directions are connected. An inductive element comprising a plurality of rectangular helical coils formed by connecting the same side end or the opposite end in the stacking direction by a bridge conductor. The inductive element according to any one of claims 1 to 3,
The inductive element, wherein the insulator and the insulating layer are made of a resin or a composite material obtained by mixing a functional material powder with a resin. The inductive element according to any one of claims 1 to 4,
The inductive element, wherein the U-shaped conductor and the bridge conductor are formed by a photolithography method. On the surface of the core substrate, a plurality of U-shaped conductors corresponding to three sides of the plurality of rectangular helical coils are formed vertically and horizontally aligned such that the open ends of the U-shaped conductors face in the same direction,
A plurality of core substrates are laminated and integrated to form a laminated core substrate,
The laminated core substrate is cut so that an open end of the U-shaped conductor is exposed,
On the cut surface where the open end of the U-shaped conductor is exposed, by forming a bridge conductor connecting the open ends by a photolithographic method, a rectangular helical coil is formed,
Forming an insulating layer covering the bridge conductor on the cut surface on which the bridge conductor is formed;
A method for manufacturing an inductive element, comprising cutting the material into individual chips to obtain an inductive element. The method for manufacturing an inductive element according to claim 6,
When laminating the core substrate, laminating and integrating the core substrate of the number of turns corresponding to the thickness of one inductive element,
By cutting the laminated core substrate so that the open ends of the coil conductors are exposed, a stick-shaped material containing a plurality of U-shaped conductors corresponding to a plurality of inductive elements is obtained, and then forming the bridge conductor A method of manufacturing an inductive element. The method for manufacturing an inductive element according to claim 6,
When laminating the core substrate, laminating and integrating the core substrate of the number of turns corresponding to the thickness of the plurality of inductive elements,
By cutting the laminated core substrate obtained in this manner so that the open ends of the coil conductors are exposed, a plate-like shape having a built-in U-shaped conductor having a width in the lamination direction corresponding to a plurality of inductive elements is built. A method for manufacturing an inductive element, comprising: forming a bridge conductor after obtaining a material. The method for manufacturing an inductive element according to claim 6,
A method for manufacturing an inductive element, comprising: providing conductor layers that are both end faces of terminal electrodes of an inductive element on both end faces in the stacking direction of the laminated core substrate. The method for manufacturing an inductive element according to claim 8,
A method of manufacturing an inductive element, comprising: providing a conductor layer to be both end faces of a terminal electrode of the inductive element on both ends in the stacking direction of the laminated core substrate and a boundary between the inductive elements. A method for manufacturing an inductive element according to any one of claims 6 to 10,
A method of manufacturing an inductive element, comprising: cutting the laminated core substrate so that insulating layers are simultaneously formed around three sides of the U-shaped conductor. A method for manufacturing an inductive element according to any one of claims 6 to 10,
As the core substrate, instead of a core substrate having a U-shaped conductor, a core substrate having a plurality of rows of ladder-shaped conductors is used,
A method for manufacturing an inductive element, characterized in that a substantially U-shaped conductor is obtained by cutting the laminated core substrate in a direction perpendicular to the longitudinal direction of the ladder-shaped conductor. A method for manufacturing an inductive element according to any one of claims 6 to 11,
In the method of manufacturing an inductive element, when forming the helical coil, two helical coils are formed per chip by connecting one bridge conductor to the U-shaped conductor in a jump. A method for manufacturing an inductive element according to any one of claims 6 to 11,
On each of the core substrates, U-shaped conductors are formed concentrically and multiplely, respectively,
On the cut surface where the open ends of the U-shaped conductors of the laminated core substrate are exposed, adjacent ones of the U-shaped conductors of the same size that are adjacent in the laminating direction are connected by the bridge conductor, and the U-shaped conductors that are adjacent in the inner and outer directions. Wherein a plurality of rectangular helical coils are formed by connecting end portions of each other with a bridge conductor.

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