JP2009088329A - Coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil component that exhibits excellent properties in a high-frequency band while adopting a structure advantageous for size reduction. <P>SOLUTION: The coil component comprises: first and second planar spiral lines that are opposed to each other with an insulation layer interposed therebetween; and first and second magnetic bodies that are disposed so as to sandwich the first and second planar spiral lines when viewed from a direction perpendicular to the first and second planar spiral lines. The first and second planar spiral lines have a portion that does not overlap with at least one of the first and second magnetic bodies when viewed from the direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coil component having excellent impedance characteristics at a high frequency, and more particularly to a coil component used as a transformer, a common mode filter, or the like.

  Increasing signal transmission speed and driving frequency are increasing in electronic devices such as personal computers and portable terminals. For example, IEEE 1394a with a transmission rate of 400 Mbps and USB 2.0 with a transmission rate of 480 Mbps are already widely used, and higher speed HDMI (700 Mbps) and IEEE 1394b (800 Mbps) are also used. Coil components such as common mode filters used in these high-speed differential transmissions are required to be compatible with high frequencies and to be small. For example, Patent Document 1 discloses an example of a coil component used as a transformer, a common mode filter, or the like. In FIG. 1 of the patent document, a laminated body is formed by alternately forming insulating layers and conductor patterns on a first magnetic substrate by a thin film formation technique, and the relative permeability of the laminated body is greater than 1.0. The second magnetic substrate is bonded by an adhesive layer to constitute a coil component. In the laminated body of the coil parts, a hole is formed in the central region surrounded by the coil pattern, and a notch is formed in the peripheral portion, so that the adhesive layer is also filled in the hole and the notch so that a closed magnetic circuit is formed. Is configured. As a result, it is disclosed that the leakage of magnetic field lines is reduced and the electromagnetic coupling degree and impedance of the common mode choke coil are increased.

Japanese Patent Laid-Open No. 11-54326

  According to Patent Document 1, it is supposed that a small and high impedance coil component can be obtained. However, in the conventional coil component as shown in Patent Document 1, when the frequency band exceeds about several hundred MHz to 1 GHz, for example, the noise attenuation amount for the common mode decreases, or the signal loss for the differential signal increases. None of the high frequency bands can exhibit sufficient characteristics.

  Therefore, an object of the present invention is to provide a coil component that exhibits excellent characteristics in a high frequency band while adopting a configuration advantageous for downsizing.

  The coil component of the present invention has first and second planar spiral lines arranged so as to face each other with an insulating layer interposed therebetween, and the direction is perpendicular to the plane of the first and second planar spiral lines. First and second magnetic bodies are disposed so as to sandwich the first and second planar spiral lines, and the first and second planar spiral lines are the first and second planes as viewed from a direction perpendicular to the plane. It has a portion that does not overlap with at least one of the second magnetic bodies. According to such a configuration, characteristics of the coil component such as noise attenuation and signal loss in the high frequency band can be improved. Furthermore, it is more preferable that the first and second planar spiral lines have a portion that does not overlap the first and second magnetic bodies when viewed from the direction.

  In the coil component, the third magnetic body is inside the spiral of the first and second planar spiral lines, the fourth magnetic body is outside, and the first and second magnetic bodies are magnetized. It is preferable that they are arranged so as to be connected in a circuit. According to such a configuration, leakage of magnetic flux generated by the spiral coil is suppressed, and the amount of noise attenuation can be further improved.

  Furthermore, in the coil component, it is preferable that the fourth magnetic body is disposed at one place. According to such a configuration, the amount of noise attenuation can be further improved.

  Further, of the first and second magnetic bodies, in the connection direction of a portion intersecting the first and second planar spiral lines so as to connect the third magnetic body and the fourth magnetic body. The width in the orthogonal direction is preferably equal to or less than the width in the direction orthogonal to the connection direction of the third magnetic body. Such a configuration is suitable for reducing the amount of noise attenuation and signal loss in the high frequency band by reducing the intersection between the first and second magnetic bodies and the first and second planar spiral lines. .

  ADVANTAGE OF THE INVENTION According to this invention, the coil component which exhibits the outstanding characteristic in a high frequency band can be provided, adopting the structure advantageous for size reduction.

  Embodiments of the coil component of the present invention will be specifically described below, but the present invention is not necessarily limited to the embodiments. In each embodiment, the same members are denoted by the same reference numerals. FIG. 1 is a diagram showing an internal structure of a rectangular laminated common mode filter which is an embodiment of the coil component of the present invention. (A) is a perspective view seen through the laminated common mode filter, (b) is a plan view seen through, (c) is a sectional view in the center. Further, FIG. 2 shows a connection configuration of a planar spiral line and a lead line. The coil component is not limited to the common mode filter but can be applied to other filters and transformers, for example.

  The first planar spiral line 3 and the second planar spiral line 4 are arranged to face each other in the insulator. Insulator layers and planar spiral lines are alternately stacked to form a coil unit 5 including a first planar spiral line 3 and a second planar spiral line 4. The first planar spiral line 3 and the second planar spiral line 4 may be opposed to each other so as to overlap each other via an insulator layer, and may be disposed on the surface of the insulator. The first and second spiral lines 3 and 4 are wound in a spiral shape whose outer shape is rectangular while being bent at 90 °. Both ends of each planar spiral line are connected to terminal electrodes on the surface of the component. In FIG. 1 (a), the drawing lines and vias associated therewith are omitted, and FIG. 2 shows their connection. One end inside the coil of the first planar spiral line 3 is connected via a via 23 to one end of a lead line 22 formed in an insulating layer adjacent to the upper side in the stacking direction. The other end of the lead wire 22 extends to the side surface of the coil portion 5 and is connected to the external electrode. On the other hand, one end inside the coil of the second planar spiral line 4 is connected to one end of a lead line 24 formed in an insulating layer adjacent to the lower side in the stacking direction via a via 25. The other end of the lead wire 24 extends to the side surface of the coil portion 5 as in the case of the lead wire 22 and is connected to the external electrode. The coil portion side surface where the other ends of the lead wires 22 and 24 are exposed and the coil portion side surface where the other outer ends of the first and second spiral lines 3 and 4 are exposed face each other.

  The first magnetic body 6 is disposed on one main surface side of the coil portion 5, and the second magnetic body 2 is disposed on the other main surface side. That is, the magnetic material is disposed so as to sandwich these planar spiral lines from a direction perpendicular to the first planar spiral line 3 and the second planar spiral line 4. In the embodiment shown in FIG. 1, the coil component constitutes an open magnetic path. The first magnetic body 6 has the same shape as the rectangular coil portion 5 in plan view (as viewed from the winding axis direction of the planar spiral line), and overlaps the entire first and second planar spiral lines. The first magnetic body may be constituted by a magnetic substrate such as a ferrite sintered body, or may be constituted by arranging a magnetic body on a substrate other than the magnetic body.

  On the other hand, as shown in FIGS. 1A and 1B, the second magnetic body 2 is a rectangle having a smaller width in one direction than the first magnetic body 6 in plan view. In the configuration shown in FIG. 1, the second magnetic body 2 is arranged so that the longitudinal direction is the lateral direction in the drawing, and both sides of the longitudinal direction overlap the sides of the first magnetic body 6 in plan view. The 2nd magnetic body 2 has overlapped so that it may orthogonally cross in a pair of side part among the rectangular 1st and 2nd plane spiral lines 3 and 4. FIG. In plan view, a part of the second magnetic body has a part located inside the first and second spiral lines and a part located outside. On the other hand, a pair of side parts orthogonal to the pair of side parts, that is, a part parallel to the longitudinal direction of the second magnetic body 2 does not overlap the second magnetic body 2. In the case of the embodiment of FIG. 1, the extending direction of the lead wires 22 and 24 and the longitudinal direction of the second magnetic body are arranged so as to be substantially orthogonal. Magnetic materials are used to suppress leakage of magnetic flux and secure high magnetic flux and to obtain high inductance characteristics. However, general magnetic materials such as sintered ferrite have a high dielectric constant, which is close to a planar spiral line. If present, a parasitic capacitance is formed between the planar spiral line and GND, and the high frequency characteristics of the coil component are deteriorated. As in the embodiment of FIG. 1, the first and second planar spiral lines 3 and 4 of the common mode filter have a portion that does not overlap at least one of the first and second magnetic bodies 6 and 2. It suppresses the formation of parasitic capacitance and contributes to the improvement of noise attenuation and signal loss on the high frequency side. From this point of view, the width in the direction perpendicular to the longitudinal direction of the portion where the second magnetic body 2 overlaps with the rectangular first and second planar spiral lines 3 and 4 is smaller. preferable. A portion of the rectangular first and second planar spiral lines 3 and 4 parallel to the longitudinal direction of the second magnetic body 2 not only forms a parasitic capacitance when it overlaps the second magnetic body 2, Since it does not work effectively as a magnetic path, it is preferable that the portion does not overlap the second magnetic body 2. On the other hand, if the width of the second magnetic body 2 is too narrow, the leakage of magnetic flux increases and the inductance decreases, so this width is the inner diameter (length of one side) of the innermost coils of the planar spiral lines 3 and 4. More preferably, it is larger than 1/2.

  In the embodiment shown in FIG. 1, the insulator 1 is disposed on the other main surface side of the coil portion 5 so as to sandwich the second magnetic body 2. Only two magnetic bodies 2 may be arranged. Such a configuration makes it more difficult to form parasitic capacitance.

  Next, a second embodiment of the coil component of the present invention will be described. FIG. 3 is a diagram showing an internal structure of the rectangular laminated common mode filter according to the second embodiment. (A) is a perspective view seen through the laminated common mode filter, (b) is a plan view seen through, (c) is a sectional view in the center. The structure shown in FIG. 3 is different from the structure shown in FIG. 1 in the configuration related to the first magnetic body on the one main surface side of the coil portion 5. Since other parts are the same as those of the embodiment shown in FIG. In the second embodiment shown in FIG. 3, similarly to the other main surface side of the coil portion 5, the first magnetic body 7 is arranged so that the longitudinal direction is the horizontal direction in the drawing. The first magnetic body 7 is overlapped so as to be orthogonal at a pair of side portions of the rectangular first and second planar spiral lines 3 and 4. On the other hand, a pair of side portions orthogonal to the pair of side portions, that is, a portion parallel to the longitudinal direction of the first magnetic body 7 does not overlap the first magnetic body 7. The effect of adopting such a configuration related to the first magnetic body is the same as that in the case where the configuration related to the second magnetic body 2 described in the first embodiment is employed. The first and second planar spiral lines have portions that do not overlap not only the second magnetic body 2 but also the first magnetic body 7 among the magnetic bodies sandwiching the first and second planar spiral lines 3 and 4. Therefore, the effect of reducing the parasitic capacitance is great. In the configuration shown in FIG. 3, the first magnetic body 7 and the second magnetic body 2 are configured in the same shape, and are arranged so as to overlap in plan view. This arrangement forms an efficient magnetic path and suppresses parasitic capacitance.

  Next, a third embodiment of the coil component of the present invention will be described. FIG. 4 is a diagram showing the internal structure of the rectangular laminated common mode filter according to the third embodiment. (A) is a perspective view seen through the laminated common mode filter, (b) is a plan view seen through, (c) is a sectional view in the center. In the structure shown in FIG. 4, the third magnetic body 12 and the fourth magnetic bodies 10 and 11 are arranged between the first magnetic body 7 and the second magnetic body 2 so as to overlap with each other in plan view. It differs from the configuration shown in FIG. 3 in that it is arranged. Since other parts are the same as those of the embodiment shown in FIG. The third magnetic body 12 is inside the spiral of the first and second planar spiral lines 3, 4, the fourth magnetic bodies 10, 11 are outside the spiral, the first magnetic body 7, and the second magnetic body. It arrange | positions so that the bodies 2 may be connected magnetically. A fourth magnetic body 10, a third magnetic body 12, and a fourth magnetic body 11 are arranged in this order along the longitudinal direction of the first and second magnetic bodies 7 and 2. The third magnetic body 12 constitutes a magnetic path inside the spiral line, and the fourth magnetic bodies 10 and 11 constitute a magnetic path outside the spiral line. Such a configuration can suppress leakage of magnetic flux, and thus can ensure high inductance in addition to suppression of parasitic capacitance formation.

  In FIG. 4, the third magnetic body and the fourth magnetic bodies 10 and 11 are prismatic shapes having a rectangular cross section, but the cross sectional shape is not particularly limited, and is selected from, for example, a square, a rectangle, a circle, and an ellipse. do it. However, from the viewpoint of space use efficiency, if the outer shape is a rectangular spiral line, the cross-sectional shape is preferably rectangular so as to be substantially similar. In the embodiment of FIG. 4, the cross-sectional areas of the fourth magnetic bodies 10 and 11 are made smaller than the cross-sectional area of the third magnetic body 12. Since the outer magnetic body of the spiral line is disposed at a plurality of locations, a sufficient cross-sectional area can be secured for the entire magnetic path even if the cross-sectional area of each outer magnetic body is reduced. By reducing the cross-sectional area of each outer magnetic body, the portion facing the spiral line can be reduced. In the embodiment of FIG. 4, the first and second magnetic bodies 7 and 2 have a rectangular parallelepiped shape, and extend in a direction extending so as to connect the third magnetic body 12 and the fourth magnetic bodies 10 and 11. The width in the vertical direction is the same as the width in the same direction of the third magnetic body 12. The width of the first magnetic body 7 and / or the second magnetic body 2 may be changed in the middle of the longitudinal direction in accordance with the width of the fourth magnetic bodies 10 and 11. By setting the width of the portion intersecting with the first and second planar spiral lines 3 and 4 to be equal to or less than the width of the third magnetic body 12 in the direction orthogonal to the connection direction, the first and second planar spiral lines It is also possible to prevent the overlap between the magnetic material and the magnetic material from increasing more than necessary.

  Here, the noise attenuation and the signal loss were evaluated for the common mode filter (structure 1) having the configuration of FIG. The common mode filter has a size of 1 mm × 1 mm and a thickness of 0.8 mm. The magnetic material is ferrite having an initial permeability of 40 MHz and a relative dielectric constant of 19 at 100 MHz. The magnetic bodies 2 and 7 have a size of 1 mm × 0.48 mm and a thickness of 0.34 mm. The magnetic bodies 10 and 11 have a size of 0.12 mm × 0.48 mm and a thickness of 0.12 mm. The magnetic body 12 has a size of 0.52 mm × 0.48 mm and a thickness of 0.12 mm. The coil is 10 μm in both line width and line spacing, and the number of turns is 4.5 turns. The insulators 1, 8, and 9 are nonmagnetic and have a relative dielectric constant of 3.5. For comparison, the entire planar spiral lines 3 and 4 overlap with the magnetic bodies 6 and 19, and the structure (structure 2) shown in FIG. Further, the structure (structure 3) shown in FIG. 7 provided with the magnetic bodies 20 and 21 having the same width as the magnetic bodies 6 and 19 was also evaluated. The results are shown in FIG. 8 and FIG. By removing the magnetic bodies 20 and 21 facing the planar spiral line from the lateral direction from the conventional structure 3 shown in FIG. 7, signal loss is improved in the 1-4 GHz band. In addition, the structure 2 is improved in noise attenuation in the 900 MHz to 3 GHz band as compared with the structure 3. Furthermore, the structure 1 in which the planar spiral line has a portion that does not overlap the first and second magnetic bodies has a remarkable effect on improving the high-frequency characteristics as compared with the structure 2. For example, structure 1 has improved signal loss at 900 MHz or higher compared to structure 3. In particular, the effect of improving the signal loss on the high frequency side is remarkable. At 6 GHz, the signal loss is improved by about 2 dB. In Structure 1, an excellent value of signal loss of −1 dB or more at 3 GHz and −2 dB or more at 6 GHz is obtained. Further, the noise attenuation is also 800 MHz to 6 GHz, which is superior to the structure 3.

  Next, a fourth embodiment of the coil component of the present invention will be described. FIG. 5 is a diagram showing the internal structure of the rectangular laminated common mode filter of the fourth embodiment. (A) is a perspective view seen through the laminated common mode filter, (b) is a plan view seen through, (c) is a sectional view in the center. The structure shown in FIG. 5 is different from the structure shown in FIG. 4 in that the number of the fourth magnetic body 15 is one and the first and second magnetic bodies 18 and 14 are short. Description of other parts similar to those of the embodiment shown in FIG. 4 is omitted. In the embodiment shown in FIG. 5, the fourth magnetic body 15 is arranged at one place on the outside so as to sandwich one side of the third magnetic body 12 and the rectangular spiral line. In the first magnetic body 18 and the second magnetic body 14, one end of the first magnetic body 18 and the other end of the third magnetic body 12 coincide with the end of the fourth magnetic body 15 in plan view. It arrange | positions so that the magnetic body 12 and the 4th magnetic body 15 may overlap. In the embodiment shown in FIG. 5, the portion overlapping the first and second planar spiral lines is one place, and therefore, it is more effective in suppressing the formation of parasitic capacitance than the embodiment shown in FIG. 4. The insulator 13 disposed around the second magnetic body 14 may be omitted.

  Here, the noise attenuation amount and the signal loss were evaluated for the common mode filter (structure 4) having the configuration of FIG. The common mode filter has a size of 1 mm × 1 mm and a thickness of 0.8 mm. The magnetic material is ferrite having an initial permeability of 40 MHz and a relative dielectric constant of 19 at 100 MHz. The magnetic bodies 14 and 18 have a size of 0.88 mm × 0.48 mm and a thickness of 0.34 mm. The size of the magnetic body 15 is 0.24 mm × 0.48 mm and the thickness is 0.12 mm. The magnetic body 12 has a size of 0.52 mm × 0.48 mm and a thickness of 0.12 mm. The coil is 10 μm in both line width and line spacing, and the number of turns is 4.5 turns. The insulators 13, 16, and 17 are nonmagnetic and have a relative dielectric constant of 3.5. For comparison, the evaluation results are also shown for the structure 3 shown in FIG. The results are shown in FIG. The high frequency characteristics of the common mode filter are further improved by changing the structure 1 shown in FIG. 4 to the structure 4 shown in FIG. Similar to the structure 1, the signal loss is improved at 900 MHz or more in the structure 4 compared to the structure 3. In particular, the effect of improving the signal loss on the high frequency side is remarkable. Compared with the structure 3, the signal loss is improved by about 2 dB at 6 GHz. In the structure 4, excellent values of signal loss of −1 dB or more at 3 GHz and −2 dB or more at 6 GHz are obtained. In structure 4, the noise attenuation in the high frequency band is remarkably improved, and is superior to structure 3 at 900 MHz to 6 GHz. In particular, 1.5 to 3 GHz is improved by 5 dB or more as compared with the structure 3.

  Next, a method for configuring a coil component according to the present invention will be described. The first to fourth magnetic bodies may be made of soft ferrite such as spinel ferrite typified by Ni—Zn ferrite and hexagonal ferrite typified by Z type and Y type. Among these, hexagonal ferrite having high magnetic anisotropy maintains the magnetic permeability up to a high frequency exceeding the frequency limit of magnetic permeability called the snake limit of spinel ferrite. Therefore, hexagonal ferrite is preferable in that high common mode impedance can be obtained up to high frequencies and high noise attenuation characteristics can be obtained. The magnetic body and the coil portion may be formed separately and then assembled, or may be formed integrally. When the magnetic body is configured separately, the magnetic body is used by processing a sintered body of the soft ferrite, a composite material with a resin, or the like into a predetermined shape. On the other hand, the coil portion is produced by pattern printing with a metal paste on a dielectric green sheet, laminating, and sintering. At this time, holes and notches for arranging the magnetic body are provided according to the embodiment. In addition, the coil part produced by providing holes and notches and a magnetic body such as a ferrite sintered body are bonded with an adhesive containing magnetic powder, and the adhesive containing the magnetic powder in the holes and notches It may be filled.

  When the laminated body and magnetic body are integrally formed, for example, the coil part is formed by pattern printing with a metal paste on a dielectric green sheet and laminated, and a green sheet of ferrite is laminated on the upper and lower sides, and then integrally fired. Can be formed. In this case, according to the embodiment, a hole may be provided in a portion where the magnetic body of the dielectric green sheet is disposed, and the magnetic paste may be printed and filled.

  The coil component may be manufactured using a thin film process using photolithography or the like, or a printed circuit board process. A conductor film is formed by sputtering or the like on a resin layer such as polyimide resin or epoxy resin, or an insulator layer such as dielectric ceramics, and then a photoresist is formed on the conductor film. Exposure is performed using a photomask having a coil line pattern. Further, after removing the resist of the unexposed portion, the conductor other than the coil line pattern is removed by etching. Thereafter, the resist is removed to form a coil line. A coil portion is obtained by further forming an insulating material thereon. Such a coil portion may be formed on a magnetic substrate. A partially formed magnetic body may be formed by a thin film process.

It is a figure which shows one Embodiment of the coil components which concern on this invention. It is a figure which shows the structure of the coil part of one Embodiment of the coil components which concern on this invention. It is a figure which shows other embodiment of the coil components which concern on this invention. It is a figure which shows other embodiment of the coil components which concern on this invention. It is a figure which shows other embodiment of the coil components which concern on this invention. It is a figure which shows an example of a coil component. It is a figure which shows an example of the conventional coil components. It is a figure which shows the characteristic of a common mode filter. It is a figure which shows the characteristic of a common mode filter. It is a figure which shows the characteristic of a common mode filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 8, 13, 17: Insulator 2, 14, 19: 2nd magnetic body 3: 1st plane spiral line 4: 2nd plane spiral line 5, 9, 16: Coil part 6, 7, 18 : First magnetic body 10, 11, 15, 20, 21: Fourth magnetic body 12: Third magnetic body 22, 24: Lead wire 23, 25: Via

Claims (4)

  The first and second planes have first and second planar spiral lines arranged so as to face each other with an insulating layer therebetween, and are perpendicular to the plane of the first and second planar spiral lines. First and second magnetic bodies are disposed so as to sandwich the spiral line, and the first and second planar spiral lines are at least one of the first and second magnetic bodies as viewed from a direction perpendicular to the plane. Coil parts with a part that does not overlap one side.   A third magnetic body is connected to the inside of the spirals of the first and second planar spiral lines, a fourth magnetic body is connected to the outside, and the first and second magnetic bodies are connected in a magnetic circuit manner. The coil component according to claim 1, wherein the coil component is arranged.   The coil component according to claim 2, wherein the fourth magnetic body is disposed at one place.   Of the first and second magnetic bodies, the part intersecting the first and second planar spiral lines is orthogonal to the connection direction so as to connect the third magnetic body and the fourth magnetic body. 4. The coil component according to claim 2, wherein a width in a direction is equal to or less than a width in a direction orthogonal to the connection direction of the third magnetic body. 5.

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