JP2010010804A - Method of manufacturing ferrite magnet element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a ferrite magnet element which is easily assembled with high precision. <P>SOLUTION: The method of manufacturing the ferrite magnet element comprises a ferrite element having first and second central electrodes arranged to intersect one another in a mutually electrically insulated state, and a pair of permanent magnets stuck on both main surfaces of the ferrite so as to apply a DC magnetic field to the ferrite. On the main surface of the permanent magnet 41, an adhesion layer 42, a metal foil (central electrode 36), an insulating layer 43, a metal foil (central electrode 35), an adhesion layer 44, the ferrite 32, an adhesion layer 45, a metal foil (central electrode 35), an insulating layer 46, a metal foil (central electrode 36), an adhesion layer 47, and the permanent magnet 41 are stacked in order. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a ferrite / magnet element incorporated in a non-reciprocal circuit element or the like.

  Conventionally, nonreciprocal circuit elements such as isolators and circulators have a characteristic of transmitting a signal only in a predetermined specific direction and not transmitting in a reverse direction. Utilizing this characteristic, for example, an isolator is used in a transmission circuit unit of a mobile communication device such as a car phone or a mobile phone.

  In general, in this type of nonreciprocal circuit element, a ferrite / magnet element composed of a ferrite having a central electrode formed thereon and a permanent magnet that applies a DC magnetic field thereto, or a predetermined matching circuit element composed of a resistor or a capacitor (capacitance). I have. In addition, a composite electronic component including a plurality of nonreciprocal circuit elements or a composite electronic component including a nonreciprocal circuit element and a power amplifier element is provided as a module.

  Conventionally, various nonreciprocal circuit elements have been proposed in Patent Documents 1, 2, 3 and the like. In the nonreciprocal circuit elements described in Patent Literatures 1 and 2, since the ferrite provided with the center electrode and the permanent magnet are not integrated, the assembly is complicated and the characteristics vary due to the assembly error. Had. In particular, the non-reciprocal circuit element described in Patent Document 2 has a problem that since the center electrode is formed of a photosensitive conductive paste, shrinkage occurs after sintering, and high accuracy cannot be maintained due to variation in shrinkage rate. It was.

The non-reciprocal circuit element described in Patent Document 3 is an integrated structure in which a ferrite provided with a center electrode is sandwiched between a pair of permanent magnets, and is easy to handle and eliminates assembly errors. Since it is necessary to sinter, the problem of variation in shrinkage ratio has not been solved. In addition, since the center electrode is formed on each of the two main surfaces of the ferrite in a separate process, it is necessary to perform alignment for forming the center electrode on one main surface and the other main surface, which is complicated. It was. Furthermore, when the ferrite is handled as a reference, the ferrite has a possibility of being broken because it is thin.
JP 2002-299912 A Japanese Patent No. 3649162 JP 2007-208943 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a ferrite / magnet element that can be easily assembled with high accuracy.

  It is another object of the present invention to provide a method for manufacturing a ferrite magnet element that does not cause errors due to sintering.

In order to achieve the above object, a method for manufacturing a ferrite magnet element according to one aspect of the present invention includes:
Manufacture of a ferrite-magnet element comprising a ferrite having a plurality of central electrodes arranged in an electrically insulated state from each other and a permanent magnet fixed to the main surface of the ferrite so as to apply a DC magnetic field to the ferrite In the method
An electrode layer to be a central electrode is formed on the main surface of the permanent magnet with a metal foil through an adhesive layer, and an electrode layer to be another central electrode is formed on the metal foil through an insulating layer thereon. A first step of attaching ferrite thereon via an adhesive layer;
An electrode layer serving as a central electrode is formed on the main surface of the ferrite with a metal foil through an adhesive layer, and an electrode layer serving as a central electrode is formed on the metal foil over the insulating layer. Two steps;
A third step of forming a through hole in the ferrite;
A fourth step of providing an electrode in the through hole;
It is provided with.

  In the method for manufacturing a ferrite / magnet element, an adhesive layer, a metal foil, an insulating layer, a metal foil, an adhesive layer, a ferrite, an adhesive layer, a metal foil, an insulating layer, and a metal foil are sequentially laminated on the main surface of the permanent magnet. Since only one positioning reference is required for stacking, accuracy is improved. Further, since the center electrode is formed of a metal foil, it is not sintered, so that shrinkage error due to sintering does not occur. Furthermore, since the lamination is performed using a relatively thick permanent magnet as a reference, the possibility of damaging the thin ferrite can be eliminated.

  According to the present invention, a ferrite / magnet element can be accurately and easily manufactured by a method of sequentially laminating materials on a permanent magnet, and the possibility of damaging a thin ferrite is eliminated. Furthermore, if an electrode is provided in the through hole by plating, the sintering process is not required for manufacturing the ferrite / magnet element, so that the accuracy is not deteriorated due to the shrinkage error.

  Embodiments of a method for manufacturing a ferrite magnet element according to the present invention will be described below with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the part and part which are common in each Example, and the overlapping description is abbreviate | omitted.

(First example of isolator, see FIGS. 1 to 5)
FIG. 1 shows an exploded perspective view of a two-port isolator 1 as a first example. The two-port isolator 1 is a lumped constant isolator, and generally includes a circuit board 20, a ferrite / magnet element 30 including a ferrite 32 and a pair of permanent magnets 41, and a matching circuit element (the capacitor C1 is a circuit board 20). And the other elements are built in the circuit board 20).

  As shown in FIG. 2, the ferrite 32 is formed with a first center electrode 35 and a second center electrode 36 which are electrically insulated from each other on the front and back main surfaces 32a and 32b. Here, the ferrite 32 has a rectangular parallelepiped shape having a first main surface 32a and a second main surface 32b which are parallel to each other.

  Further, the permanent magnet 41 applies, for example, an epoxy-based adhesive layer 42 to the main surfaces 32a and 32b so that a DC magnetic field is applied to the ferrite 32 in a direction substantially perpendicular to the main surfaces 32a and 32b (see FIG. 4). To form a ferrite / magnet element 30. The main surface of the permanent magnet 41 has the same dimensions as the main surfaces 32a and 32b of the ferrite 32, and is arranged with the main surfaces facing each other so that their external shapes match. In addition, the manufacturing method of the ferrite magnet element 30 will be described in detail with reference to FIGS.

  The first center electrode 35 is formed of a metal foil (for example, Cu foil) as described below. That is, as shown in FIG. 2, the first center electrode 35 is formed on the first main surface 32a of the ferrite 32 from the lower right and is inclined at a relatively small angle with respect to the long side at the upper left. The second main surface 32b is formed so as to overlap with the first main surface 32a in a see-through state through the relay electrode 35a on the relay 32c, and one end thereof is an electrode 35b formed on the lower surface 32d. It is connected to the. The other end of the first center electrode 35 is connected to an electrode 35c formed on the lower surface 32d. Thus, the first center electrode 35 is wound around the ferrite 32 for one turn. And the 1st center electrode 35 and the 2nd center electrode 36 demonstrated below cross | intersect in the state which the insulating layer 43 (refer FIG. 4) was formed between and insulated from each other. The crossing angle of the center electrodes 35 and 36 is set as necessary, and input impedance and insertion loss are adjusted.

  The second center electrode 36 is formed of a metal foil (for example, Cu foil). In the second center electrode 36, first, the 0.5th turn 36a is inclined at a relatively large angle with respect to the long side from the lower right to the upper left on the first main surface 32a and intersects the first center electrode 35. The first turn 36c is formed so as to intersect the first central electrode 35 substantially perpendicularly on the second main surface 32b via the electrode 36b on the upper surface 32c. . The lower end of the first turn 36c goes around the first main surface 32a through the electrode 36d on the lower surface 32d, and the 1.5th turn 36e is parallel to the 0.5th turn 36a on the first main surface 32a. It is formed in a state of intersecting with the electrode 35 and wraps around the second main surface 32b via the electrode 36f on the upper surface 32c. Similarly, the second turn 36g, the electrode 36h, the 2.5th turn 36i, the electrode 36j, the third turn 36k, and the electrode 36l are formed on the surface of the ferrite 32, respectively. Further, both ends of the second center electrode 36 are connected to electrodes 35c and 36l formed on the lower surface 32d of the ferrite 32, respectively. The electrode 35c is shared as a connection electrode at each end of the first center electrode 35 and the second center electrode 36.

  The electrodes 35a, 35b, 35c, 36b, 36d, 36f, 36h, 36j, and 36l are formed by plating Ag, Cu or the like in the recesses 37 (see FIG. 3) formed in the upper and lower surfaces 32c and 32d of the ferrite 32. Has been. In addition, dummy recesses 38 are formed on the upper and lower surfaces 32c and 32d in parallel with the recesses 37, and dummy electrodes 39a, 39b, and 39c are formed. This type of electrode is formed by forming a through hole in a mother ferrite substrate, plating an electrode material on the through hole, and then cutting at a position where the through hole is divided.

  FIG. 4 shows a state in which the respective materials are laminated on the main surface 32a of the ferrite 32. The second center electrode 36 is formed on the main surface 32a via the adhesive layer 44, and the insulating layer 43 is further formed. The first center electrode 35 is formed through the permanent magnet 41, and the permanent magnet 41 is attached through the adhesive layer 42. Although not shown in FIG. 4, each material is similarly laminated on the main surface 32 b side of the ferrite 32. The manufacturing method will be described below with reference to FIGS.

  As the ferrite 32, YIG ferrite or the like is used. The first and second center electrodes 35 and 36 are formed by etching a metal foil such as Cu. As the insulating layer 43 of the center electrodes 35 and 36, a resin film such as polyimide can be used. These can also be formed by printing, transferring, photolithography and the like.

  As the permanent magnet 41, a strontium-based, barium-based, or lanthanum-cobalt-based ferrite magnet is usually used. As the adhesive layer 42 that bonds the permanent magnet 41 and the ferrite 32, for example, a one-component thermosetting epoxy adhesive is used.

  The substrate 20 is an LTCC ceramic substrate, on the surface of which terminal electrodes 25a, 25b, 25c, 25d, and the like for mounting chip-type capacitors C1 which are part of the ferrite-magnet element 30 and the matching circuit element are provided. 25e, input / output electrodes 26 and 27, and a ground electrode 28 are formed. Further, matching circuit elements (capacitors C2, CS1, CS2, and resistor R) described below with reference to FIG. 5 are formed on the substrate 20 as internal electrodes, and a predetermined circuit is configured through via-hole conductors and the like. .

  The ferrite magnet element 30 is placed on the substrate 20, and the electrodes 35b, 35c, 36l on the lower surface 32d of the ferrite 32 are integrated with the terminal electrodes 25a, 25b, 25c on the substrate 20 by reflow soldering. . The capacitor C1 is reflow soldered to the terminal electrodes 25d and 25e on the substrate 20.

(Circuit configuration, see FIG. 5)
Here, one circuit example of the isolator 1 is shown in an equivalent circuit of FIG. The input port P1 is connected to the matching capacitor C1 and the termination resistor R via the matching capacitor CS1, and the matching capacitor CS1 is connected to one end of the first center electrode 35. The other end of the first center electrode 35 and one end of the second center electrode 36 are connected to the terminating resistor R and the capacitors C1 and C2, and to the output port P2 through the capacitor CS2. The other end of the second center electrode 36 and the capacitor C2 are connected to the ground port P3.

  In the two-port isolator 1 having the above equivalent circuit, one end of the first center electrode 35 is connected to the input port P1, the other end is connected to the output port P2, and one end of the second center electrode 36 is connected to the output port P2. Since the other end is connected to the ground port P3, a two-port lumped constant isolator with low insertion loss can be obtained. Further, during operation, a large high-frequency current flows through the second center electrode 36 and almost no high-frequency current flows through the first center electrode 35.

  Further, the ferrite / magnet element 30 is mechanically stable because the ferrite 32 and the pair of permanent magnets 41 are integrated, and is a robust isolator that is not deformed or damaged by vibration or impact.

(Manufacturing process, see FIGS. 6 to 8)
The manufacturing process of the ferrite magnet element 30 will be described with reference to FIGS. 6 to 8, a part of the ferrite / magnet element 30 is shown as a cross section.

  The ferrite 32 is manufactured as follows. That is, a microwave magnetic powder mainly composed of yttrium oxide and iron oxide and a polyvinyl alcohol-based organic binder were dispersed in an organic solvent to obtain a slurry. Next, the microwave magnetic powder was molded by a dry press or the like and fired at a temperature of about 1300 to 1400 ° C. In place of the main component, magnetic powder such as manganese magnesium ferrite, nickel zinc ferrite, calcium vanadium garnet may be used.

  Further, the arrangement order of the first center electrode 35 and the second center electrode 36 may be either first. 2 and 4 show an example in which the second center electrode 36 is disposed on the inner side and the first center electrode 35 is disposed on the outer side. In this manufacturing process, the first center electrode 35 is disposed on the inner side, and the second center electrode 35 is disposed on the inner side. An example in which the center electrode 36 is disposed outside will be described.

  First, in step 1, the adhesive layer 42 is formed on the main surface of the permanent magnet 41. In step 2, a metal foil is attached onto the adhesive layer 42, an electrode layer that becomes the center electrode 36 is formed by photolithography, and a marker that serves as a reference for lamination is provided. In step 3, the insulating layer 43 is formed. In step 4, a metal foil is stuck on the insulating layer 43, and an electrode layer to be the center electrode 35 is formed by photolithography. In step 5, the adhesive layer 44 is formed. In step 6, the ferrite 32 is stuck on the adhesive layer 44.

  Next, in step 7, through holes 33 (corresponding to the upper and lower concave portions 37 and 38) are formed in the ferrite 32. The through hole 33 is processed by a laser method, but may be processed by a sandblast method or the like. In step 8, the electrode 34 is formed in the through hole 33 by plating. This electrode 34 is also formed on the portion where the adhesive layer 44 and the insulating layer 43 are not formed, and connects the center electrodes 35 and 36 with the upper and lower surfaces 32c and 32d of the ferrite 32, respectively. In step 9, an adhesive layer 45 is formed on the main surface of the ferrite 32. In step 10, a metal foil is attached onto the adhesive layer 45, and an electrode layer that becomes the center electrode 35 is formed by photolithography. In step 11, the insulating layer 46 is formed. In Step 9 and Step 11, the electrode 34 is formed as an opening by photolithography.

  Next, in step 12, a metal foil is stuck on the insulating layer 46, and an electrode layer to be the center electrode 36 is formed by photolithography. In step 13, the electrode 34 is formed by plating. The electrode 34 formed here is connected to the center electrodes 35 and 36, and is also connected to the electrode 34 formed in the step 8. In step 14, an adhesive layer 47 is formed. In step 15, another permanent magnet 41 is stuck on the adhesive layer 47.

  The above manufacturing process is performed by a so-called multi-cavity method. That is, the permanent magnet 41 and the ferrite 32 are a mother magnet and a mother ferrite, and a predetermined material is laminated on the surface of the permanent magnet 41 and the ferrite 32 so as to form one unit of the element 30, and the shape is processed. Divide into predetermined sizes.

  In the manufacturing process, the formation of the electrode 34 in the process 8 may be omitted, and the electrode 34 may be integrally formed in the process 13. Further, the formation of the through hole 33 in the step 7 is omitted (in this case, the step 8 is also omitted), the through hole 33 is formed between any of the steps 9 to 13, and the electrode is formed in the step 13. 34 may be integrally formed. Further, after Step 2 and Step 15, a through hole is formed on the lower surface of the permanent magnet 41 (the mounting surface of the permanent magnet 41 with respect to the circuit board 20), and an electrode 34 is formed on the through hole by plating. Also good. The bottom surface of the ferrite / magnet element 30 thus formed is shown in FIG. By forming the electrode 34 on the lower surface of the permanent magnet 41, the soldering strength when the ferrite / magnet element 30 is mounted on the substrate 20 is improved.

  In the manufacturing process, the adhesive layer 42, the metal foil (electrode 36), the insulating layer 43, the metal foil (electrode 35), the adhesive layer 44, the ferrite 32, the adhesive layer 45, the metal foil (on the main surface of the permanent magnet 41 ( The electrode 35), the insulating layer 46, the metal foil (electrode 36), the adhesive layer 47, and the permanent magnet 41 can be laminated in order, and only one positioning reference is required for the lamination, thus improving accuracy. . In addition, the center electrodes 35 and 36 are formed of metal foil, and the electrodes 34 (35a, 35b, 35c, 36b, 36d, 36f, 36h, 36j, 36l) are formed by plating. Therefore, shrinkage error due to sintering does not occur.

(See second example of isolator, FIG. 10)
FIG. 10 is an exploded perspective view of the 2-port isolator 2 as the second example. The two-port isolator 2 basically has the same configuration as that of the first example except that the matching circuit elements C1, C2, CS1, CS2, and R are all chip-type printed circuit board 20A. It is in the point soldered to the surface. In addition to the terminal electrodes 25a, 25b, 25c for connecting both ends of the first and second center electrodes 35, 36 to the surface of the printed circuit board 20A, terminal electrodes 25d, 25e for connecting each matching circuit element. Is formed. Although not shown, input / output electrodes and a ground electrode are also formed.

(Refer to the first example of the composite electronic component, FIG. 11 and FIG. 12)
FIG. 11 shows a composite electronic component 3 as a first example. The composite electronic component 3 is configured as a module by mounting the isolator 2 and a power amplifier 81 on the surface of a printed circuit board 82. Necessary chip type circuit elements 83 a to 83 f are also mounted around the power amplifier 81.

  FIG. 12 shows a circuit configuration of the composite electronic component 3. The output of the impedance matching circuit 86 is input to the high frequency power amplifier circuit 81, and the output is input to the isolator 2 through the impedance matching circuit 85.

(Refer to the second example of the composite electronic component, FIG. 13)
FIG. 13 shows a composite electronic component 4 as a second example. This composite electronic component 4 is configured as a module by mounting isolators 2A and 2B on the surface of a printed circuit board 91. The isolators 2A and 2B have the same configuration as that of the isolator 2. The isolator 2A is used in, for example, the 800 MHz band, and the isolator 2B is used in, for example, the 2 GHz band.

(Refer to FIG. 14 for the third example of the composite electronic component)
FIG. 14 shows a composite electronic component 5 as a third example. The composite electronic component 5 is configured as a module by mounting the set of the isolator 2A and the power amplifier 81A and the set of the isolator 2B and the power amplifier 81B on the surface of the printed circuit board 96, respectively.

(Other examples)
In addition, the manufacturing method of the ferrite magnet element which concerns on this invention is not limited to the said Example, It can change variously within the range of the summary.

  In particular, the configuration of the matching circuit is arbitrary. Also, as a method of joining the ferrite / magnet element and the matching circuit element to the surface of the substrate, in addition to the solder joining shown in the above embodiment, joining by a conductive adhesive, joining by ultrasonic waves, joining by bridge bonding, etc. It may be used. Further, the ferrite-magnet element may have a permanent magnet fixed only to one main surface of the ferrite.

It is an exploded perspective view showing the 1st example of a 2 port type isolator. It is a perspective view which shows the ferrite with a center electrode. It is a perspective view which shows the element body of the said ferrite. It is a disassembled perspective view which shows a ferrite magnet element. It is an equivalent circuit diagram showing an example of a circuit of a 2-port isolator. It is explanatory drawing which shows a manufacturing process. It is explanatory drawing which shows the manufacturing process following FIG. It is explanatory drawing which shows the manufacturing process following FIG. It is a bottom view of a ferrite magnet element in which a through hole and an electrode are formed also on the lower surface of a permanent magnet. It is an exploded perspective view showing the 2nd example of a 2 port type isolator. It is a perspective view which shows the 1st example of a composite electronic component. It is a block diagram which shows the circuit structure of the said composite electronic component. It is a perspective view which shows the 2nd example of a composite electronic component. It is a perspective view which shows the 3rd example of a composite electronic component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2, 2A, 2B ... Isolator 3, 4, 5 ... Composite electronic component 30 ... Ferrite magnet element 32 ... Ferrite 33 ... Through hole 34 ... Electrode 35 ... 1st center electrode 36 ... 2nd center electrode 41 ... Permanent magnet 42, 44, 45, 47 ... Adhesive layer 43, 46 ... Insulating layer

Claims (8)

Manufacture of a ferrite-magnet element comprising a ferrite having a plurality of central electrodes arranged in an electrically insulated state from each other and a permanent magnet fixed to the main surface of the ferrite so as to apply a DC magnetic field to the ferrite In the method
An electrode layer to be a central electrode is formed on the main surface of the permanent magnet with a metal foil through an adhesive layer, and an electrode layer to be another central electrode is formed on the metal foil through an insulating layer thereon. A first step of attaching ferrite thereon via an adhesive layer;
An electrode layer serving as a central electrode is formed on the main surface of the ferrite with a metal foil through an adhesive layer, and an electrode layer serving as a central electrode is formed on the metal foil over the insulating layer. Two steps;
A third step of forming a through hole in the ferrite;
A fourth step of providing an electrode in the through hole;
A method for producing a ferrite / magnet element, comprising:   The ferrite magnet according to claim 1, further comprising a fifth step of attaching another permanent magnet on the electrode layer via an adhesive layer after the second step. Device manufacturing method.   3. The method according to claim 1, wherein the third step and the fourth step are performed after the first step, and the fourth step is performed again through the second step. 4. Manufacturing method for ferrite and magnet elements.   3. The method for manufacturing a ferrite magnet element according to claim 1, wherein the third step and the fourth step are performed after the second step. 4.   5. The method for manufacturing a ferrite / magnet element according to claim 1, wherein the metal foil is made of Cu.   6. The method of manufacturing a ferrite magnet element according to claim 1, wherein a central electrode is formed from the metal foil by photolithography.   The method for manufacturing a ferrite / magnet element according to claim 1, wherein the electrode is provided in the through hole by plating.   The ferrite according to any one of claims 1 to 7, wherein the permanent magnet and the ferrite are a mother magnet and a mother ferrite, and are divided into a predetermined size at least after the completion of the fourth step. -Manufacturing method of a magnet element.

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