JP2007294880A - Thin-film magnetic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin-film magnetic device capable of more efficiently improving magnetic permeability in a high frequency area. <P>SOLUTION: Slits 16 extend in one direction (X-axis direction) in a laminate plane of a magnetic film 14B. The slits 16 are each formed in only a pair of areas facing each other (in this case, two areas vertically positioned on an opening 15) among four regions (four regions vertically and horizontally positioned on the opening 15) divided in a winding direction from the extending region of a coil 13. With this configuration, a stress in the magnetic film 14B is reduced, and the deterioration can be suppressed in the magnetic permeability μ due to the influence of an anti-magnetic field Hd. Thus, the magnetic permeability can be somewhat maintained even in a high frequency region. In this case, a plurality of strip-like magnetic films may be formed along the one direction in the laminate plane. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thin film magnetic device including a thin film coil and a magnetic film.

  Conventionally, thin film magnetic devices such as thin film inductors and thin film transformers including thin film coils and magnetic films have been widely used as integrated passive components in the field of electronic equipment for various applications.

  FIG. 27 shows an example of a conventional thin film magnetic device (thin film inductor 101) configured by a rectangular spiral coil. FIG. 27A shows a planar configuration, and FIG. Each cross-sectional structure of the III-III part shown to (A) is each represented. In this thin film inductor 101, a laminated film in which an insulating film 112, a rectangular spiral coil 113 having terminals 113T1 and 113T2, and a magnetic film 114 having an opening 115 at the center are laminated in this order on a substrate 111. It has a structure.

  By the way, in recent years, in such a thin film magnetic device, a high frequency application in a GHz (gigahertz) band or the like is expected, and a magnetic film having good high frequency characteristics, specifically, a magnetic film exhibiting high permeability in a high frequency region. Is required.

  Thus, for example, Patent Document 1 and Patent Document 2 propose a technique in which a plurality of slits are formed on a magnetic film so as to improve the magnetic permeability in a high frequency region.

JP-A-8-172015 JP 2001-143929 A

  However, the thin film magnetic device disclosed in Patent Document 1 has a problem that the magnetic permeability decreases due to the stress generated in the magnetic film. Further, in the thin film magnetic device disclosed in Patent Document 2, since a plurality of slits are formed over the entire magnetic film, the magnetic permeability is reduced due to an excessive demagnetizing field generated in the magnetic film. was there.

  As described above, in the conventional technique, the permeability in the high frequency region has not reached a practically sufficient level due to the influence of the stress generated in the magnetic film and the demagnetizing field. Therefore, further improvement of the magnetic permeability in the high frequency region is desired.

  The present invention has been made in view of such problems, and an object thereof is to provide a thin film magnetic device capable of more effectively improving the magnetic permeability in a high frequency region.

  The first thin-film magnetic device of the present invention includes a thin-film coil and a plurality of strip-like magnetic films laminated on the extending surface of the thin-film coil. Is extended in one direction only in a pair of regions facing each other among the four regions obtained by dividing the wire along the winding direction. The “extending region of the thin film coil” means not only a region on the thin film coil in a strict sense but also a peripheral region thereof.

  A second thin film magnetic device of the present invention includes a thin film coil and a plurality of magnetic films stacked on the extending surface of the thin film coil, and the extending region of the thin film coil extends along the winding direction. A plurality of slits extending in one direction are formed only in the magnetic films present in a pair of regions facing each other among the four regions obtained by division. The term “slit” means a strip-shaped or strip-shaped concave surface as well as a strip-shaped or strip-shaped opening.

  In the thin film magnetic device of the present invention, since a plurality of strip-like magnetic films extending in one direction or a plurality of slits in the magnetic film are formed on the extending surface of the thin-film coil, the width direction of each strip-like magnetic film or each slit The sum of the stresses on the belt-like magnetic film or the magnetic film is reduced. Therefore, since the amount of distortion of the belt-like magnetic film or the magnetic film is also reduced, the magnetic permeability is improved. Further, these strip-shaped magnetic films or slits are formed only in a pair of regions facing each other among four regions obtained by dividing the extending region of the thin film coil along the winding direction. Compared with the case where the magnetic field is formed in all the two regions, a decrease in magnetic permeability due to the influence of the demagnetizing field can be suppressed. Therefore, it is easy to maintain a certain degree of magnetic permeability in the high frequency region.

  In the first thin film magnetic device of the present invention, it is preferable that the strip-like magnetic film is formed so as to overlap the pattern of the thin film coil. In the second thin film magnetic device of the present invention, it is preferable that the slit is formed in a region between patterns of the thin film coil. In the case of such a configuration, the distance between the strip-shaped magnetic film or the magnetic film and the coil pattern is reduced, so that the magnetic permeability is further increased.

  In the first thin film magnetic device of the present invention, it is preferable that the direction of the easy axis of magnetization of the band-shaped magnetic film is matched with the width direction of the band-shaped magnetic film. In the second thin film magnetic device of the present invention, it is preferable that the direction of the easy axis of magnetization of the magnetic film coincides with the width direction of the slit. When configured as described above, a certain degree of magnetic permeability is maintained in the high frequency region not only when the easy axis of magnetization and the thin film coil are orthogonal but also when they are orthogonal. Therefore, the magnetic permeability in the high frequency region is more effectively improved.

  According to the thin film magnetic device of the present invention, a plurality of strip-like magnetic films or slits in the magnetic film extending in one direction are formed on the extending surface of the thin-film coil, and the strip-like magnetic films or slits are formed on the thin-film coil. The extension region is formed only in a pair of regions facing each other out of the four regions formed by dividing the extension region along the winding direction. A decrease in permeability due to the influence of a magnetic field can be suppressed, and a certain degree of permeability can be maintained even in a high frequency region. Therefore, the magnetic permeability in the high frequency region can be improved more effectively.

  Hereinafter, the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment) will be described in detail with reference to the drawings.

[First Embodiment]
1 and 2 show the configuration of a thin film inductor 1 as a thin film magnetic device according to a first embodiment of the present invention. FIG. 1 shows an XY plane configuration, and FIG. 2 shows the configuration in FIG. The XZ cross-sectional structure along the II-II line is represented. The thin film inductor 1 has a laminated structure in which an insulating film 12, a thin film coil 13, and a magnetic film 14 are formed in this order on a substrate 11.

The substrate 11 is a rectangular substrate that supports the entire thin film inductor 1 and is made of, for example, glass, silicon (Si), aluminum oxide (Al ₂ O ₃ ; so-called alumina), ceramics, semiconductor, resin, or the like. . Note that the constituent material of the substrate 11 is not necessarily limited to the series of materials described above, and can be freely selected.

The insulating film 12 electrically insulates the coil 13 from the periphery and is made of, for example, an insulating material such as silicon oxide (SiO ₂ ).

  The coil 13 constitutes an inductor between one end (13T1) and the other end (13T2), and is made of a conductive material such as copper (Cu). The coil 13 has a rectangular spiral structure wound so that both the terminals 13T1 and 13T2 are led out to the outside in the XY plane, and the coil 13 extends along the X-axis direction. It has a pattern (first coil pattern) and a coil pattern (second coil pattern) extending along the Y-axis direction. In addition, the portion of the coil 13 that leads to the terminal 13T2 is arranged below the winding portion so that the portion that leads to the outside without contacting the winding portion that includes the portion that leads to the terminal 13T1 of the coil 13 is introduced. Has been. In FIG. 2, in order to simplify the illustration, the portion of the coil 13 that leads to the terminal 13T2 is not shown.

  The magnetic film 14 is for increasing the inductance of the thin film inductor 1 and has a rectangular opening 15 in the center. The magnetic film 14 has an easy magnetization axis Me in the X-axis direction and a hard magnetization axis Mh in the Y-axis direction, and exhibits uniaxial anisotropy. The magnetic film 14 is made of, for example, a magnetic material such as a cobalt (Co) alloy, an iron (Fe) alloy, or a nickel iron alloy (NiFe; so-called permalloy). Among these, from the practical viewpoint of the thin film inductor 1, for example, a cobalt zirconium tantalum (CoZrTa) alloy or a cobalt zirconium niobium (CoZrNb) alloy is preferable as the cobalt alloy. The shape of the opening 15 is not limited to a rectangular shape, and may be an arbitrary shape.

  In the magnetic film 14, the second coil pattern is formed in a region where the easy axis Me and the coil 14 are substantially orthogonal, that is, in a region corresponding to the second coil pattern extending in the Y-axis direction of the coil 14. A plurality of strip-shaped (strip-shaped) slits 16 extending in a direction substantially perpendicular to the easy magnetization axis Me, that is, in the Y-axis direction (hard magnetization axis Mh direction) are formed. From another point of view, the magnetic film 14 has four regions (four regions located above, below, left and right of the opening 15) obtained by dividing the extending region of the coil 13 along the winding direction. A plurality of slits 16 extending in one direction (Y-axis direction) are formed only in a pair of regions facing each other (here, two regions located on the left and right sides of the opening 15). The width of these slits 16 (slit width S) is about 5 μm to 20 μm, and the width of the magnetic film 14 between each slit 16 (pattern width L) is about 0.1 mm to 5 mm as will be described later. Here, each slit 16 penetrates the magnetic film 14, but is not limited to completely penetrate, and may be a strip-shaped (band-shaped) concave surface.

  Next, an example of a method for manufacturing the thin film inductor 1 will be described with reference to FIGS. 3 to 7 show an example of a method for manufacturing the thin-film inductor 1. FIGS. 3 and 5 show an XZ cross-sectional configuration, and FIGS. 4, 6 and 7 show an XY plane. Each configuration is shown.

  First, as shown in FIG. 3A, the insulating film 12 and the coil 13 are formed on the substrate 11 made of the above-described material. The insulating film 12 is formed by, for example, a sputtering method, and the coil 13 is formed by, for example, a plating method. Further, in order to embed the coil 13 in the insulating film 12 as shown in the figure, for example, the coil 13 is formed while the insulating film 12 is dividedly formed.

  Subsequently, as shown in FIG. 3B, the magnetic film 14 made of the above-described material is uniformly formed on the insulating film 12 and the coil 13. The magnetic film 14 is formed by, for example, a sputtering method.

Subsequently, as shown in FIG. 4, heat treatment is performed while applying a fixed magnetic field H <b> 1 within the laminated surface (XY plane) of the magnetic film 14. At this time, the application direction of the fixed magnetic field H1 is substantially parallel to one of the first and second coil patterns formed by the coil 13, that is, in this case, the X-axis direction or the Y-axis direction (the X-axis direction in FIG. 4). To become). The magnitude of the fixed magnetic field H1 is, for example, about 300 × 10 ³ / 4π [A / m] (= 300 Oe), the heat treatment temperature is, for example, about 330 ° C., and the heat treatment time is, for example, about 1 hour. Then, as shown in FIG. 5, the easy magnetization axis Me is generated along the application direction (X-axis direction) of the fixed magnetic field H1, and the hard magnetization axis Mh is generated along the direction (Y-axis direction) orthogonal to the application direction. The magnetic film 14 exhibits uniaxial anisotropy.

  Subsequently, as shown in FIG. 6A, a photoresist pattern 2 for forming the opening 15 and the slit 16 in the magnetic film 14 is formed by a photoresist method. The formation region of the photoresist pattern 2 corresponds to the formation region of the opening 15 and the slit 16, and as described above, the central portion of the magnetic film 14 is the formation region of the opening 15, and the easy magnetization axis Me. A region where the coil 14 and the coil 14 are substantially orthogonal, that is, a region corresponding to the second coil pattern extending in the Y-axis direction of the coil 14 is a formation region of the slit 16 and a direction substantially orthogonal to the easy magnetization axis Me, That is, a plurality of strip-shaped (strip-shaped) slits 16 are formed along the Y-axis direction (hard magnetization axis Mh direction).

  Subsequently, as shown in FIG. 6B, the magnetic film 14 is etched using a predetermined etching material to form the opening 15 and the slit 16.

  Finally, the thin film inductor 1 as shown in FIGS. 1 and 2 is manufactured by removing the photoresist pattern 2 using a predetermined resist removing material.

For example, as shown in FIG. 7, it is desirable to perform heat treatment while applying a rotating magnetic field H2 in the laminated surface (XY plane) of the magnetic film 14 thereafter. Since the stress on the magnetic film 14 is relaxed and the magnetic anisotropy is reduced, the permeability μh in the hard magnetization axis Mh direction can be further increased, and the inductance of the thin film inductor 1 can be further increased. is there. The magnitude of the rotating magnetic field H2 is, for example, about 300 × 10 ³ / 4π [A / m] (= 300 Oe), the rotational speed of the rotating magnetic field H2 is, for example, about 90 [rpm], and the heat treatment temperature is, for example, about 330 ° C. The heat treatment time is about 1 hour, for example.

  In the method of manufacturing the thin film inductor 1, the heat treatment is performed while applying the fixed magnetic field H1, and the slit 16 is formed after forming the easy magnetization axis Me and the hard magnetization axis Mh. After forming 16 (and opening 15), heat treatment may be performed while applying fixed magnetic field H1, as shown in FIG. 4, to form easy axis Me and hard axis Mh. Specifically, a slit 16 is formed in the laminated surface of the magnetic film 14 so as to be substantially parallel to a part of the coil 13, that is, one of the first and second coil patterns. Heat treatment is performed while applying a fixed magnetic field H1 in a direction perpendicular to the slit 16 in the (XY plane). Even when manufactured in this way, the thin film inductor 1 similar to the above case can be manufactured.

  Furthermore, in the manufacturing method of the thin film inductor 1 described above, after the magnetic film 14 is formed, heat treatment is performed while applying the fixed magnetic field H1, and the easy axis Me and the hard axis Mh are formed. The easy magnetization axis Me and the hard magnetization axis Mh may be formed by forming the magnetic film 14 while applying the fixed magnetic field H1 using the magnetron sputtering method. Even when manufactured in this way, the thin film inductor 1 similar to the above case can be manufactured.

  Next, the magnetic characteristics of the thin film inductor 1 formed in this way will be described in detail with reference to FIGS. 8 to 10 are examples of the frequency dependence of the magnetic permeability μ when the pattern width L is changed from 6 mm to 0.02 mm, and FIG. 11 is an example of the dependence of the magnetic permeability μ on the pattern width L. 12 shows an example of a magnetization curve (relation between applied magnetic field H and magnetization M), and FIG. 13 shows an example of a relationship between magnetic permeability μ and resonance frequency fr. 14 to 17 used magnetic colloids showing enlarged examples of the planar form of the magnetic film 14 when the pattern width L = 0.5 mm, 0.2 mm, 0.05 mm, and 0.02 mm, respectively. FIG. 18 schematically shows details of the magnetic domain structure shown in the micrograph, and FIG. 19 shows an example of the relationship between the 90 ° domain occupancy and the pattern width L described later. It represents. Note that the pattern width L = 6 mm in each figure corresponds to a conventional case in which the slit 16 is not formed, and is given as a comparative example.

The manufacturing conditions of the thin film inductor 1 in each example are as follows. First, the magnetic film 14 is formed using a DC magnetron sputtering method while applying a fixed magnetic field H1, and the target is CoZrTa. Further, when forming the slit 16, a positive resist for semiconductor is used to form the photoresist pattern 2, and an etching material (etchant) is iron chloride (FeCl ₃ ): H ₂ O: hydrogen fluoride (HF). ) = 1: 2: 0.2, and acetone is used as a resist remover. Further, an impedance analyzer is used for evaluating the manufactured thin film inductor 1, and a ferrite yoke method is used as a measuring method.

First, according to the frequency dependence of the magnetic permeability μ shown in FIGS. 8 to 10, the magnetic permeability μh in the direction perpendicular to the application direction of the fixed magnetic field H <b> 1 (direction of hard magnetization Mh) is the pattern width L = 6 mm˜0. On the other hand, the permeability μe in the horizontal direction (direction of easy magnetization Me) of the application direction of the fixed magnetic field H1 hardly changes to 1 mm, and the slit 16 having L = 6 mm is formed as the value of the pattern width L decreases. From the comparative example, the slit 16 is formed and the pattern width L becomes narrower), so that the magnetic permeability μe is lowered and a certain value is maintained up to the high frequency region (approximately when L = 0.2 mm). 10 ⁷ Hz = about 10 MHz), and it can be seen that the resonance frequency fr also increases.

  The relationship between the magnetic permeability μ and the pattern width L is summarized as shown in Table 1 below. FIGS. 11A and 11B are graphs based on the values shown in Table 1. FIG. 11A shows the case where the frequency is f = 1 kHz. 11 (B) represents the case where the frequency is f = 1 MHz.

  According to Table 1 and FIGS. 11A and 11B, first, the permeability μh in the vertical direction hardly changes regardless of the pattern width L even when the frequencies are f = 1 kHz and 1 MHz. I understand. Further, in the case where the frequency f = 1 kHz in the relatively low frequency region (FIG. 11A), the horizontal magnetic permeability μe monotonously decreases as the value of the pattern width L decreases, whereas in the high frequency region, In the case of the frequency f = 1 MHz (FIG. 11B), it increases once as the value of the pattern width L becomes smaller compared to the comparative example (L = 6 mm), and has a peak value near L = 0.5 mm. I understand that Therefore, in order to increase the magnetic permeability μ in such a high frequency region, the slit 16 is formed, and as can be seen from FIG. 11B, the pattern width L between the plurality of slits is 0.1 mm or more and 0. It is desirable that it is about 5 mm or less. Further, in order to further increase the magnetic permeability μ, the pattern width L is more preferably 0.3 mm or more and 2 mm or less, and further preferably 0.3 mm or more and 1 mm or less.

  Here, with reference to FIGS. 12A and 12B, the following is considered when the relationship between the formation of the slit 16 and the increase in the magnetic permeability μ in the high frequency region is considered. 12A shows the magnetization curve in the comparative example (L = 6 mm) in which the slit 16 is not formed, and FIG. 12B shows the magnetization in the case where the slit 16 is formed (L = 0.5 mm). Each curve is represented.

  First, it is known that the following equations (1) and (2) are established between the anisotropic magnetic field Hk and the magnetic permeability μ or the resonance frequency fr in the hard magnetization axis Mh direction of the magnetic film. However, these equations (1) and (2) are considered to hold in the same manner in the direction of the easy axis Me. In the equation, Bs represents a saturation magnetic flux, Ms represents a saturation magnetization, μ0 represents a magnetic permeability in vacuum, and γ represents a magnetorotation ratio.

  When focusing on the easy magnetization axis Me direction, the magnetization curve shown in FIG. 12B has an inclination compared to the magnetization curve of the comparative example shown in FIG. 12A due to the influence of the demagnetizing field Hd. The value of the anisotropic magnetic field Hk increases (Hk increases to (Hk + Hd)). Therefore, it can be seen from the equations (1) and (2) that the value of the magnetic permeability μ decreases, but the resonance frequency fr increases, so that the magnetic permeability μ can maintain a certain value up to the high frequency region. . In this way, the value of the anisotropic magnetic field Hk increases due to the influence of the demagnetizing field Hd, so that the horizontal magnetic permeability μe in the high frequency region increases and the magnetic permeability μ increases as a whole.

  Table 2 summarizes the relationship between the resonance frequency fr and the horizontal magnetic permeability μe when the pattern width L is changed from 6 mm to 0.02 mm. FIG. 13 is a graph based on the values shown in Table 2.

  Also from Table 2 and FIG. 13, as the slit 16 is formed and the value of the pattern width L becomes smaller, the value of the horizontal magnetic permeability μe itself decreases, but the resonance frequency fr increases. I understand.

  Next, according to the micrographs of the magnetic film 14 shown in FIGS. 14 to 17, a plurality of magnetic domains magnetized in the width direction (X-axis direction) of each slit 16 are formed in the slit 16 of the magnetic film 14. It turns out that it is located in a line along the longitudinal direction (Y magnetic domain direction) of the sandwiched band-like region. Further, even if the pattern width L is narrowed from FIG. 14 to FIG. 17, the lateral domain, that is, the magnetic domain structure in the width direction (X-axis direction) of the band-shaped region remains laterally long, and 90 ° of the easy axis Me It can be seen that a phenomenon such as rotation does not occur. However, as the pattern width L becomes narrower, the aspect ratio of the magnetic domain (ratio of the length in the minor axis direction to the length in the major axis direction of the magnetic domain) changes and gradually changes toward the square (the aspect ratio increases). ) The aspect ratio of each magnetic domain is desirably 0.3 or less because of the relationship with the 90 ° domain occupancy described below. This is because the magnetic permeability μ can be maintained to a higher frequency side due to the influence of the demagnetizing field Hd as described above.

  Furthermore, the spike structure as indicated by reference signs P1 and P2 in FIG. 14 (L = 0.5 mm) disappears in FIGS. 15 to 17 (L = 0.2, 0.05, 0.02 mm), and instead The triangular domains (90 ° domain) whose magnetization direction is the longitudinal direction (Y-axis direction) of the band-shaped region as indicated by reference numerals P3 to P5 are the opposite ends of the magnetic domain whose magnetization direction is the width direction (X-axis direction). It turns out that it is located in a line along the longitudinal direction (Y-axis direction).

  FIG. 18 schematically shows these magnetic domain structures and corresponds to a band-like region (magnetic film 14 having a pattern width L) existing between the slits 16. Here, as described above, a plurality of magnetic domains 14 </ b> D are formed and arranged along the longitudinal direction (Y-axis direction, hard magnetization axis Mh direction). Each of the magnetic domains 14D includes a pair of magnetic domains 14De whose magnetization direction is the above-described width direction (X magnetic domain direction, easy magnetization axis Me direction), and a pair of magnetic domains 14De whose longitudinal direction is the magnetization direction and positioned at both ends of the magnetic domain 14De. It is composed of a magnetic domain (90 ° domain) 14Dh. In addition, the magnetization directions by the magnetic domains 14De and 14Dh constitute a closed loop, and the adjacent magnetic domains 14D are opposite to each other in the closed loop direction.

  Further, according to the relationship between the pattern width L shown in FIG. 19 and the 90 ° domain occupancy in the magnetic domain 14, the 90 ° domain occupancy is almost 0% when the pattern width L is 0.5 mm or more. Although it hardly exists in the magnetic domain 14, when the pattern width L is less than 0.5 mm, it can be seen that the 90 ° domain occupancy increases monotonously. Further, as shown in FIG. 11B, the permeability μe in the horizontal direction (easy magnetization axis Me direction) has a peak value near the pattern width L = 0.5 mm. It can also be seen that the horizontal permeability μe, which tends to increase as the pattern width L illusions, tends to decrease as the pattern width L increases. Therefore, from these results, in order to more effectively improve the magnetic permeability μ in the high frequency region, it is desirable that the 90 ° domain occupancy is 12% or less.

  As described above, in the present embodiment, in the band-shaped region sandwiched between the plurality of slits 16 in the magnetic film 14, the width direction (X magnetic domain direction, easy axis Me direction) of the band-shaped region is defined as the longitudinal direction. Since the magnetic domains 14De to be aligned are arranged along the longitudinal direction (Y-axis direction) of the belt-like region, the magnetization easy axis Me and the coil 13 are substantially parallel to each other and substantially orthogonal to each other. In any case, a certain degree of magnetic permeability can be maintained in the high frequency region. Therefore, the magnetic permeability in the high frequency region can be improved more effectively.

  In particular, in the present embodiment, the slit 16 is formed corresponding to only the region where the easy axis Me of the magnetic film 14 and the coil 13 are substantially orthogonal to each other, and the direction in which the slit 16 is orthogonal to the easy axis Me (magnetization). Since it is made to extend in the direction of the difficult axis Mh), the magnetic permeability at high frequency in a region where the easy magnetization axis Me and the coil 13 are substantially orthogonal (region corresponding to the second coil pattern in which the slit 16 extends). Can be selectively increased. Therefore, a certain degree of magnetic permeability can be maintained in the high frequency region not only in the region where the easy axis Me and the coil 13 are substantially parallel (region corresponding to the first coil pattern) but also in the region substantially orthogonal to each other. It becomes possible to further effectively improve the magnetic permeability in the high frequency region.

  Further, since the band-shaped region is formed so as to overlap the second coil pattern of the coil 13, the distance between the magnetic film 14 and the second coil pattern in the band-shaped region can be shortened, and the magnetic permeability can be further improved. It becomes possible.

  Further, in the belt-like region, the magnetic domains 14Dh (90 ° domain) are arranged along the longitudinal direction (Y-axis direction) of the belt-like region while being arranged opposite to both ends in the width direction (X-axis direction) of the belt-like region. Therefore, it is possible to effectively promote the increase in the resonance frequency fr caused by the demagnetizing field Hd in the magnetic domain 14De sandwiched between the pair of magnetic domains 14Dh. Therefore, the magnetic permeability in the high frequency region can be further effectively improved.

  Furthermore, according to the manufacturing method of the thin film inductor 1 as the thin film magnetic device of the present embodiment, the manufacturing process is not particularly complicated. Therefore, a thin film magnetic device exhibiting high permeability in the high frequency region as described above is provided. It can be easily obtained.

  In the present embodiment, the case where the slit 16 is formed corresponding to only the region where the easy axis Me and the coil 13 are substantially orthogonal to each other has been described. However, in addition to this, other regions such as FIG. As in the thin film inductor 1A shown in FIG. 1, the slits 16 may be formed on a diagonal line from the opening 15 on the magnetic film 14A. That is, a plurality of strip-like magnetic films 14A may be formed along one direction (in this case, the easy axis Me direction and the X axis direction) in the laminated surface. Even when configured in this manner, the same effects as in the present embodiment can be obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  FIG. 21 shows the configuration (XY plane configuration) of the thin film inductor 1B as the thin film magnetic device according to the present embodiment. In this figure, the same components as those of the thin film inductor 1 (FIG. 1) of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the thin film inductor according to the present embodiment, a plurality of magnetic film 14B is extended in a predetermined direction (corresponding to a region where easy axis Me and coil 13 are substantially parallel in FIG. 21). A slit 16 is formed. That is, in the thin film inductor 1 of the first embodiment shown in FIG. 1, the slit 16 is formed corresponding to the region where the easy axis Me of the magnetic film 14 and the coil 13 are substantially orthogonal to each other. In the thin film inductor of the present embodiment, the plurality of slits 16 extending in a predetermined direction in the laminated surface are formed without being limited to the region where the easy axis Me and the coil 13 are substantially orthogonal to each other. It has become.

  Specifically, in the thin-film inductor 1B shown in FIG. 21, four regions (four regions located on the top, bottom, left, and right of the opening 15) obtained by dividing the extending region of the coil 13 along the winding direction thereof. A plurality of slits 16 extending in one direction (X-axis direction) are formed only in a pair of regions facing each other (here, two regions positioned above and below the opening 15). Each of the plurality of slits 16 is formed in a region between the coil patterns of the coil 13 (a region between the first coil patterns in FIG. 21). The other configuration of the thin film inductor 1B and the manufacturing method thereof are basically the same as those of the thin film inductor 1.

  With such a configuration, the thin film inductor 1B produces the following stress reduction effect and demagnetizing field suppression effect in the magnetic film 14B.

  FIG. 22 is a YZ cross-sectional configuration for explaining the stress reduction effect of the thin-film inductor 1B, and FIG. 22A is a cross-sectional configuration of a conventional thin-film inductor 101 in which no slit is formed in the magnetic film as a comparative example. FIG. 22B illustrates a cross-sectional configuration of the thin film inductor 1B of the present embodiment.

  In the comparative example (thin film inductor 101) shown in FIG. 22A, since no slit is formed in the magnetic film 114, the stress F101 is likely to be generated in the magnetic film 114 in various directions. Therefore, as shown in the figure, the thin film inductor 101 itself is easily bent in the stacking direction (Z-axis direction). Further, since the stress F101 increases, the magnetostriction constant of the magnetic film 114 also increases, and the magnetic permeability μ of the magnetic film 114 decreases. Therefore, it is difficult to maintain a certain degree of permeability μ in the high frequency region.

  On the other hand, in the thin film inductor 1B of the present embodiment shown in FIG. 22B, the slit 16 is formed along one direction (X-axis direction) in the laminated surface of the magnetic film 14B. The summation of the stress F1 with respect to the width direction (Y-axis direction) of each slit 16 is avoided, and the stress in the magnetic film 14B is reduced. Therefore, since the distortion amount of the magnetic film 14B is also reduced, the magnetic permeability μ of the magnetic film 14B is improved as compared with the magnetic film 114 of the comparative example. In this way, in the thin film inductor 1B, it becomes easy to maintain a certain degree of magnetic permeability μ in the high frequency region.

  Further, in this thin film inductor 1B, each slit 16 is formed of four regions (four regions located on the top, bottom, left, and right of the opening 15) obtained by dividing the extending region of the coil 13 along the winding direction. Since each slit 16 is formed over the entire magnetic film, that is, in all four regions, since it is formed only in a pair of regions facing each other (here, two regions located above and below the opening 15). As compared with the above, the decrease in the magnetic permeability μ due to the influence of the demagnetizing field Hd can be suppressed. Therefore, in this thin film inductor 1B, it is easier to maintain the magnetic permeability μ.

  As described above, in the present embodiment, the slits 16 extending in one direction (X-axis direction) in the laminated surface of the magnetic film 14B are formed, and each slit 16 is wound around the extension region of the coil 13. Of the four regions divided along the direction (four regions located on the top, bottom, left and right of the opening 15), only a pair of regions facing each other (here, two regions located above and below the opening 15) Since it is formed, it is possible to suppress the decrease in the magnetic permeability μ due to the influence of the demagnetizing field Hd while reducing the stress in the magnetic film 14B and to maintain the magnetic permeability.

  Further, since each slit 16 is formed in the region between the first coil patterns of the coil 13, the distance between the magnetic film 14B and the first coil pattern in this band-like region is the same as in the first embodiment. And the magnetic permeability can be further improved.

  In the present embodiment, as shown in FIG. 21, the description has been given of the case where the slit 16 is formed corresponding to the region where the easy magnetization axis Me and the coil 13 are substantially parallel. May be formed on the magnetic film 14B, and the formation position of the slit 16 is not limited to this.

  In addition to the slits 16 shown in FIG. 21, the slits 16 are also formed in other regions, for example, diagonal lines from the openings 15 on the magnetic film 14B as in the thin film inductor 1A shown in FIG. You may do it. That is, a plurality of strip-like magnetic films may be formed along one direction in the laminated surface (in the case of FIG. 21, the magnetization difficult axis Mh direction, the Y axis direction). Even when configured in this manner, the same effects as in the present embodiment can be obtained.

  Although the present invention has been described with reference to the first and second embodiments, the present invention is not limited to these embodiments, and various modifications can be made.

  For example, in the above embodiment, the case where the coil 13 is composed of a rectangular spiral coil having the first and second coil patterns substantially orthogonal to each other has been described, but the shape of the coil 13 that is a thin film coil is This is not a limitation. For example, like the thin film inductors 1C to 1E shown in FIGS. 23A to 23C, the magnetic films 14C to 14E are circular (may be elliptical) and the coil 13 is also a circular spiral, for example. It may be the case. In this case, the plurality of slits 16 may be formed along the direction (hard magnetization axis Mh direction) orthogonal to the easy magnetization axis Me regardless of the shape of the coil 13. In other words, the magnetic films 14C to 14E may have the easy axis Me in the width direction of the plurality of slits 16. Further, for example, as in the thin film inductor 1F shown in FIG. 24, the coil 13 may be a rectangular spiral coil instead of a square shape.

  Further, the coil may be a meander coil 13G having a rectangular shape, for example, like a thin film inductor 1G shown in FIG. 25, and the coil may be a solenoid coil 13H, for example, like the thin film inductor 1H shown in FIG. There may be.

  In the above embodiment, the thin film inductor has been described as an example of the thin film magnetic device, but the present invention can also be applied to a thin film transformer or the like. That is, as long as the magnetic film described in the above embodiment and a predetermined electrode are provided, the present invention is not limited to a thin film inductor, and can be widely applied as a thin film magnetic device.

  Further, the material, film formation method, and film formation conditions of each layer described in the above embodiment are not limited, and other materials and thicknesses may be used, and other film formation methods and film formation conditions may be used. Good.

It is a top view showing the plane composition of the thin film magnetic device concerning a 1st embodiment of the present invention. It is sectional drawing showing the cross-sectional structure of the thin film magnetic device along the II-II line | wire shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the thin film magnetic device shown in FIG. It is a top view for demonstrating the manufacturing method of the thin film magnetic device following FIG. It is a top view for demonstrating the manufacturing method of the thin film magnetic device following FIG. It is sectional drawing for demonstrating the manufacturing method of the thin film magnetic device following FIG. It is a top view for demonstrating the manufacturing method of the thin film magnetic device following FIG. It is a characteristic view showing an example of the frequency dependence of the magnetic permeability in the thin film magnetic device shown in FIG. It is a characteristic view showing an example of the frequency dependence of the magnetic permeability in the thin film magnetic device shown in FIG. It is a characteristic view showing an example of the frequency dependence of the magnetic permeability in the thin film magnetic device shown in FIG. It is a characteristic view showing an example of the pattern width dependence of the magnetic permeability in the thin film magnetic device shown in FIG. It is a characteristic view showing an example of the magnetization curve in the thin film magnetic device shown in FIG. 1 with the thing of a comparative example. It is a characteristic view showing an example of the relationship between the magnetic permeability and resonance frequency in the thin film magnetic device shown in FIG. It is a microscope picture which expands and shows an example of the plane form of the magnetic film shown in FIG. It is a microscope picture which expands and shows an example of the plane form of the magnetic film shown in FIG. It is a microscope picture which expands and shows an example of the plane form of the magnetic film shown in FIG. It is a microscope picture which expands and shows an example of the plane form of the magnetic film shown in FIG. It is a schematic diagram for demonstrating the detail of the magnetic domain structure shown in FIGS. It is a characteristic view showing an example of the relationship between the occupation rate of a 90 degree domain and pattern width in the thin film magnetic device shown in FIG. It is a top view showing the plane composition of the thin film magnetic device concerning the modification of a 1st embodiment. It is a top view showing the plane composition of the thin film magnetic device concerning a 2nd embodiment of the present invention. It is sectional drawing for demonstrating the stress reduction effect in the thin film magnetic device shown in FIG. It is a top view showing the plane composition of the thin film magnetic device concerning the modification of the present invention. It is a top view showing the plane composition of the thin film magnetic device concerning the modification of the present invention. It is a top view showing the plane composition of the thin film magnetic device concerning the modification of the present invention. It is a top view showing the plane composition of the thin film magnetic device concerning the modification of the present invention. It is the top view and sectional drawing showing the structure of the conventional thin film magnetic device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1A-1H ... Thin film inductor, 11 ... Board | substrate, 12 ... Insulating film, 13, 13F-13H ... Coil, 13T1, 13T2 ... Terminal, 14, 14A-14H ... Magnetic film, 14D, 14Dh ... Magnetic domain, 14Dh ... Magnetic domain (90 ° domain), 15 ... opening, 16, 17 ... slit, 2 ... photoresist pattern, Me ... easy magnetization axis, Mh ... hard magnetization axis, L ... pattern width, S ... slit width, H1 ... fixed magnetic field, H2 ... rotating magnetic field, m ... magnetization direction, F1 ... stress.

Claims (6)

A thin film coil;
A plurality of strip-like magnetic films laminated on the extending surface of the thin-film coil,
The plurality of strip-like magnetic films extend in one direction only in a pair of regions facing each other among four regions obtained by dividing the extending region of the thin film coil along the winding direction. A thin film magnetic device characterized by that. The thin film magnetic device according to claim 1, wherein the strip-shaped magnetic film is formed so as to overlap with a pattern of the thin film coil. 3. The thin film magnetic device according to claim 1, wherein the direction of the easy axis of magnetization of the band-shaped magnetic film coincides with the width direction of the band-shaped magnetic film. A thin film coil;
A plurality of magnetic films laminated on the extending surface of the thin film coil,
A plurality of slits extending in one direction are formed only in the magnetic films existing in a pair of regions facing each other among four regions obtained by dividing the extending region of the thin film coil along the winding direction. A thin film magnetic device characterized by The thin film magnetic device according to claim 4, wherein the slit is formed in an inter-pattern region of the thin film coil. 6. The thin film magnetic device according to claim 4, wherein a direction of an easy axis of the magnetic film coincides with a width direction of the slit.

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