JP2015141945A - coil component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component capable of dealing with various requests such as miniaturization, improvement in inductance characteristics, reduction in Rdc, and improvement in connection stability with an external electrode.SOLUTION: A coil component includes: an insulator 10 made of resin; a coil part composed of a belt-like conductor 21 provided in the insulator 10 and a via type conductor 30; a drawing part composed of a columnar conductor electrically connected to both ends of the coil part; and external electrodes 51 and 52 to which the drawing part is electrically connected. The coil component has: a first layer composed of a resin layer; a second layer composed of the resin layer and the belt-lie conductor; a third layer composed of the resin layer and the via type conductor; a fourth layer composed of the resin layer, the belt-like conductor and the via type conductor; a fifth layer composed of the resin layer and the columnar conductor; and an external electrode.

Description

  The present invention relates to a coil component, and more particularly to a coil component as an electronic component that can be surface-mounted on a circuit board built in an electric device or the like.

  Conventionally, a coil component is mounted on an electronic device or the like. Particularly, a coil component used in a portable device has a chip shape and is surface-mounted on a circuit board built in the portable device or the like. As an example of the prior art, in Patent Document 1, a board in which a spiral conductor having at least one end connected to an external electrode is incorporated in an insulating resin made of a cured product, and the spiral direction of the conductor is mounted. A chip coil formed so as to be parallel to the surface has been proposed. When the chip coil of Patent Document 1 is mounted on a substrate of an electronic device, the Q value (Quality factor) of the coil is unlikely to decrease and the inductance is unlikely to change.

JP 2006-324489 A

  Recently, electronic devices are required to be smaller and have higher performance, and accordingly, coil components are also required to be smaller. In view of such demands, an object of the present invention is to provide a coil component that can meet various demands for downsizing, improvement in inductance characteristics, reduction in Rdc, and improvement in connection stability with external electrodes.

As a result of intensive studies by the present inventors, a new method for forming internal electrodes has been found, and the present invention characterized by the following has been completed.
(1) A coil component comprising an insulator made of resin, a coil-shaped inner conductor provided in the insulator, and an external electrode electrically connected to the inner conductor, the resin component comprising: A first layer comprising: a second layer comprising a resin layer and at least one strip-like conductor on the first layer; and a third layer comprising a resin layer and at least two via-like conductors on the second layer. A layer, a fourth layer comprising a resin layer, at least one strip-like conductor and at least two via-like conductors on the third layer; and a resin layer and at least two columnar conductors on the fourth layer. A fifth layer, and an external electrode on the fifth layer, and the first to fifth resin layers integrally form an insulator, and the second to fifth layer strip conductors and The columnar conductor constitutes a coiled inner conductor, and the fourth layer columnar conductor is connected to the outer electrode. Le parts.
(2) The coil component according to (1), wherein the area of the fourth layer strip conductor is larger than the area of the fourth layer via conductor.
(3) the area of the via conductor of the fourth layer is 50μm ² ~320μm ² (1) coil component.
(4) The coil component according to (3), wherein the maximum area of the fourth-layer strip-shaped conductor is greater than 1 and less than or equal to 100 times the minimum area of the fourth via-shaped conductor.
(5) a coil component of the area of the via conductor of the fourth layer is 20μm ² ~80μm ² (1).
(6) The coil component according to (5), wherein the maximum area of the fourth-layer strip conductor is greater than 1 and less than or equal to 50 times the minimum area of the fourth-layer via conductor.
(7) The second and fourth layer strip conductors, the fifth columnar conductors, the third and fourth layer via conductors, and the external electrodes are formed by photolithography ( Coil parts of 1) to (6).
(8) The coil component according to (1) or (7), wherein the external electrode is formed by forming a seed layer on the fifth layer and plating on the seed layer.
(9) The insulator has a rectangular parallelepiped shape having a length L, a width W, and a height H, and the relationship L> H ≧ W is established for the L, W, and H, and the L is 0.2 to The coil component of (4), (6), or (7), which is 0.4 mm, W is 0.1 to 0.2 mm, and H is 0.1 to 0.35 mm.

  According to the present invention, the structure of the coil component is characterized by the arrangement of the conductors formed in each layer, so that the inductance can be achieved through maximizing the circulation efficiency (1t wrap) and maximizing the coil (maximizing the volume of the insulator). Improvement of characteristics is expected. In addition, by pulling out the columnar conductor, the conductor cross-sectional area can be secured without affecting the coil circumference, and the Rdc can be reduced and the connection stability between the external electrodes can be achieved. According to a preferred embodiment, even if the component is a small coil component such as a so-called 0402 size (0.4 mm × 0.2 mm × 0.2 mm) or 0201 size (0.2 mm × 0.1 mm × 0.1 mm), The cross-sectional area of the columnar conductor can be secured, and a reduction in Rdc is expected. Further, the columnar taper can be minimized, and there is almost no change in the partial cross-sectional area or material density, and a stable conductor can be obtained.

It is a model see-through | perspective perspective view of the coil components of this invention. Each layer in the coil component of this invention is typically represented.

  The present invention will be described in detail with appropriate reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and in the drawings, the characteristic portions of the invention may be emphasized and expressed, so that the accuracy of the scale is not necessarily guaranteed in each part of the drawings. Not.

  FIG. 1 is a schematic perspective view of a coil component of the present invention. A coil component 1 manufactured according to the present invention includes an insulator 10, coiled inner conductors (hereinafter also referred to as “coil portions”) 21, 22, 30, 40 and external electrodes 51, 52. The coil portions 21, 22, 30, and 40 are provided inside the insulator 10. The external electrode 51 is provided outside the insulator 10 and is electrically connected to the coil portions 21, 22, 30, and 40. The coil portion 40 is formed by a third-layer via conductor, a fourth-layer via conductor, and a fifth-layer columnar conductor that is also a lead-out portion.

  The insulator 10 is made of a resin, and this resin is preferably cured by heat, light, chemical reaction or the like, and specific examples thereof include, but are not limited to, polyimide, epoxy resin, and liquid crystalline polymer. Further, the resin may contain an inorganic substance. By using silica powder or the like as the inorganic substance, the strength of the insulator can be increased and charging can be reduced.

  The insulator has a rectangular parallelepiped shape having a length L, a width W, and a height H. In FIG. 1, the direction of the length L, the width W, and the height H is indicated by arrows for the purpose of explaining the directionality. Here, for L, W, and H, the relationship L> H ≧ W is established. That is, the length of the longest side is defined as the length L of the rectangular parallelepiped. When the width W and the height H are the same length, the specification of the width W and the height H is arbitrary, but in the present invention, the external electrode is formed on a surface perpendicular to the height direction. , Width W and height H are defined. As will be described later, in the present invention, the coil component 1 is manufactured by sequentially forming layers in the height direction H from the upper side of the drawing in FIG. 1 toward the lower side of the drawing. The “plane perpendicular to the height direction” may hereinafter be referred to as an LW plane, and similarly, other planes may be referred to as an LH plane or an HW plane. In addition, about the arrow which shows the direction of L, W, and H in FIG. 1, it does not specify arrangement | positioning of the coil components at the time of use, but is attached for description of a structure and a manufacturing method.

  The coil component of the present invention may be small, and for L, W, and H, L is preferably 0.2 to 0.4 mm, and W is preferably 0.1 to 0.2 mm. , H is preferably 0.1 to 0.35 mm. These numerical values substantially correspond to the dimensions of the coil parts.

  FIG. 2 schematically shows each layer in the coil component of the present invention. 2A to 2E represent first to fifth layers, which will be described later, respectively, and FIG. 2F represents the vicinity of the external electrode. 2 are parallel to the WL plane in FIG. The order from (A) to (F) in FIG. 2 corresponds to the order from the upper side to the lower side in FIG.

  According to the present invention, the first layer is formed of the resin layer. FIG. 2A is a plan view of the first layer. Preferably, as a preparatory step before forming the first layer, a release resin is applied to a predetermined thickness on a substrate (not shown) formed of silicon, glass, sapphire, or the like and cured. The release resin can be used without any particular limitation, and non-limiting examples include silicone adhesives. The means for applying the release resin is not particularly limited, and examples include the use of a spin coater. By forming the release resin before forming the first layer, the insulator can be easily peeled off from the substrate in a later step.

  In forming the resin layer 11 as the first layer, a resin to be a part of the insulator 10 is applied to the substrate or the release resin, and a curing process is performed. For the pretreatment, application, and curing treatment of the resin, conventional techniques can be used as appropriate. For example, the thickness may be adjusted by a spin coater in the application, or after curing, by the chemical action of an abrasive or a polishing liquid. You may use for the chemical mechanical polishing process (CMP process) performed.

  A second layer is formed on the first layer. Here, the direction “up” is intended to indicate the direction in which the layer structure is sequentially formed, and is opposite to the “vertical direction” of the paper surface in the form shown in FIG. FIG. 2B is a plan view of the second layer. The second layer includes a resin layer 12 and at least one strip-shaped conductor 21. The resin layer 12 is made of a resin that is to be a part of the insulator 10, and is preferably made of the same material as the resin layer 11 in the first layer. The strip-shaped conductor 21 is a conductor that should become a part of the coil portion. When the insulator 10 has a rectangular parallelepiped shape, the longitudinal direction of the strip conductor 21 is preferably parallel to the longest side in the rectangular parallelepiped shape. More preferably, the strip-shaped conductor 21 has a rectangular shape, and more preferably, each corner in the rectangular shape is rounded. The strip conductor 21 is formed by plating. A specific method for producing the resin layer 12 and the strip-shaped conductor 21 is not particularly limited, and photolithography is preferable. A seed layer is formed by sputtering, a resist film corresponding to the strip-shaped conductor 21 is formed by photolithography, and then the surface of the seed layer is plated to form the strip-shaped conductor 21, and the resist film and the seed layer are removed. A method of exposing the above-described band-shaped conductor 21 by a polishing process after covering the entire surface with a resin that is a material of the resin layer 12 can be mentioned.

  Examples of the material for the seed layer include, but are not limited to, Ti, Cu, W (tungsten), and Ta. Examples of the method for forming the seed layer include, but are not limited to, sputtering. The method for forming the resist film is not particularly limited, and examples thereof include, but are not limited to, application of a resist material using a spin coater, followed by pre-baking, exposure processing using a pattern mask, development using an organic developer such as TMAH, and descum processing. . The descum process is a process of removing a resist film residue by plasma irradiation or the like.

  The method for the plating treatment is not particularly limited, and conventional techniques can be used as appropriate. Examples of the plating metal include Cu and Ag. The method for removing the resist film and the seed layer is not particularly limited, and examples include removing the resist film using a stripping solution and removing the seed layer with an acid or alkali. Examples of the method for exposing the strip-shaped conductor 21 after application of the resin include the above-described CMP treatment.

  A third layer is formed on the second layer. FIG. 2C is a plan view of the third layer. The third layer is composed of a resin layer and at least two via conductors. In the embodiment shown in FIG. 2C, the third layer is composed of the resin layer 13 and via conductors 30 and 41. The resin layer 13 is formed of a resin that should become a part of the insulator 10, and is preferably made of the same material as the resin layer 11 in the first layer. The via conductors 30 and 41 are conductors that should be part of the coil portion. The via conductors 30 and 41 are formed by plating. The specific manufacturing method of the resin layer 13 and the strip-shaped conductor 41 is not particularly limited, and for example, the manufacturing method of the resin layer 12 and the strip-shaped conductor 21 in the second layer described above can be used. This is the same as in the case of the second layer manufacturing method described above.

  Preferably, the via conductors 30 and 41 in the third layer are all formed so as to be directly connected to the strip conductor 21 in the second layer. Further, two of the columnar conductors (reference numeral 41) in the third layer are preferably not directly connected to the band-shaped conductor 22 in the fourth layer, which will be described later, but directly to the via conductors 42 in the fourth layer. Connecting. Preferably, the via conductors 30 other than the two via conductors 41 in the third layer are directly connected to the strip conductors 22 in the fourth layer described later.

  A fourth layer is formed on the third layer. FIG. 2D is a plan view of the fourth layer. The fourth layer includes the resin layer 14, the strip-shaped conductor 22, and the via-shaped conductor 42. The fourth layer has at least one strip conductor and at least two via conductors. The resin layer 14 is made of a resin that is to be a part of the insulator 10, and is preferably made of the same material as the resin layer 11 in the first layer. The strip-shaped conductor 22 and the via-shaped conductor 42 are conductors that should be part of the coil portion. The strip-shaped conductor 22 and the via-shaped conductor 42 are formed by plating. The specific manufacturing method of the resin layer 14 and the conductors 22 and 42 is not particularly limited. For example, the manufacturing method of the resin layer 12 and the strip-shaped conductor 21 in the second layer described above can be used. The preferred embodiment is also the same as in the case of the second layer manufacturing method described above.

  Preferably, only two via conductors 42 are provided in the fourth layer, and both of them connect the third layer via conductor 41 and the fifth layer columnar conductor 43 described later directly. It is formed. The strip conductors 22 in the fourth layer are preferably formed non-parallel to the second strip strip conductors 21 by projecting in the height direction. More preferably, the band conductor 22 of the fourth layer is formed so as to connect the positions where one end of each of the two adjacent band conductors 21 in the second layer is projected in the height direction. Thereby, as one turn of the winding portion, one end of the second layer strip conductor 21 reaches one end of the fourth layer strip conductor 22 via the third layer via conductor 30, and A structure is obtained that reaches the other end of the second strip-shaped conductor 21 (the conductor adjacent to the aforementioned conductor) via the other end of the third layer via the via-shaped conductor 30 different from the above.

  Thus, by arranging both the strip-shaped conductor 22 and the via-shaped conductor 42 in the fourth layer, the number of times of plating in the entire manufacturing method of the present invention is consequently reduced.

The shapes of the via conductors 42 and the strip conductors 22 in the fourth layer are arbitrary. Among them, the area of the largest strip conductor is 100 times or less, and preferably 50 times or less, the area of the smallest conductor. Of the via conductors 42 formed in the fourth layer, the area of the smallest conductor is preferably 50 μm ² or more, more preferably 20 μm ² . Of the conductors 22 and 42 formed in the fourth layer, the largest conductor is preferably 100 times or less, more preferably 50 times or less the area of the smallest via conductor 42. As a result, it is possible to cope with the miniaturization of parts. Specifically, a small coil such as a so-called 0402 size (0.4 mm × 0.2 mm × 0.2 mm) or 0201 size (0.2 mm × 0.1 mm × 0.1 mm) Even if it is a part, the cross-sectional area of the columnar conductor can be secured, the Rdc can be reduced, the columnar taper can be minimized, and there is almost no change in the partial cross-sectional area or material density. By obtaining a conductor and making the conductor cross-sectional area uniform, a partial change in Rdc can be suppressed, and an improvement in Q value is expected. Of the conductors 42 and 22 formed in the fourth layer, the upper limit of the area of the smallest conductor is preferably 320 μm ² , and more preferably 80 μm ² . Here, the area of the conductor means the area of the conductor portion appearing in the WL cross section of the fourth layer.

  The fourth layer strip conductor 22 is preferably formed such that each corner of the cross section perpendicular to the plating formation direction is rounded. A cross section perpendicular to the plating formation direction is a surface depicted in FIG. Preferably, the radius of curvature R at the roundness provided at each corner is 10 to 50% of the width B of the strip conductor 22. The width B of the strip conductor 22 is the length in the short direction of the strip conductor 22 in a cross section perpendicular to the plating formation direction. By making such a roundness, the plating growth is stabilized even if the strip conductor 22 is small.

  A fifth layer is formed on the fourth layer. FIG. 2E is a plan view of the fifth layer. The fifth layer includes the resin layer 15 and the columnar conductor 43. The resin layer 15 is made of a resin that should become a part of the insulator 10, and preferably made of the same material as the resin layer 11 in the first layer. The columnar conductor 43 corresponds to a conductor (leading portion) to be directly connected to an external electrode described later. The columnar conductor 43 is formed by plating. The specific manufacturing method of the resin layer 15 and the column conductor 43 is not particularly limited. For example, the manufacturing method of the resin layer 12 and the strip conductor 21 in the second layer described above can be used, and a preferable mode in that case. This is the same as in the case of the second layer manufacturing method described above.

  Preferably, only two columnar conductors 43 in the fifth layer are provided, and each is formed so as to be directly connected to the via conductors 42 in the fourth layer. More preferably, two of the columnar conductors (reference numeral 41) in the third layer, the via conductors 42 in the fourth layer, and the columnar conductors 43 in the fifth layer are integrated with the strip conductor 21 in the second layer. A conductor (reference numeral 40 in FIG. 1) is formed via an external electrode to be described later. Of the conductor 40, the portion of the fifth layer (that is, the columnar conductor 43) is also referred to as a lead-out portion.

  An external electrode is formed on the fifth layer. FIG. 2F is a plan view of a layer including an external electrode. The method for forming the external electrodes 51 and 52 is not particularly limited, and preferably includes photolithography. The specific implementation of photolithography is not particularly limited. A seed layer is formed by sputtering, a resist film is then formed in a shape corresponding to the external electrodes 51 and 52, and the surface of the seed layer is plated. There is a method of forming the external electrodes 51 and 52 and removing the resist film and the seed layer.

  Examples of the material for the seed layer include, but are not limited to, Ti, Cu, W (tungsten), and Ta. Examples of the method for forming the seed layer include, but are not limited to, sputtering. There is no particular limitation on the method of forming the resist film, and the application of the resist material using a spin coater, followed by pre-baking, exposure processing using a pattern mask, development using an organic developer such as TMAH, and the descum processing described above are not limited. This is a process of removing a resist film residue by plasma irradiation or the like.

  The method for the plating treatment is not particularly limited, and conventional techniques can be used as appropriate. Examples of the plating metal include Cu and Ag. The method for removing the resist film and the seed layer is not particularly limited. For example, the resist film may be removed using a stripping solution, and the seed layer may be removed with an acid or alkali, whereby stability can be obtained.

  Two external electrodes are preferably formed on the same surface, and the external electrodes 51 and 52 are directly connected to one columnar conductor 43 formed on the fifth layer.

  Thus, a coil component can be manufactured. The resin layers 11 to 15 formed of the layers constitute the insulator 10 together. A coil portion is formed inside the insulator 10. In the coil portion, the second-layer strip-shaped conductor 21, the third-layer via-shaped conductor 30, and the fourth-layer strip-shaped conductor 22 constitute an integrated structure of the coil. The third layer columnar conductor 41 and the fourth layer via conductor 42 are integrated to form the end of the coil portion. The end portion is electrically connected to the external electrodes 51 and 52 through the fifth-layer columnar conductor 43. In this way, the conductor 40 that connects the coil winding structure and the external electrodes 51 and 52 is formed.

  In the coil component of the present invention, the conventional technique can be appropriately used for the method of forming the conductor, the resin layer, etc., and therefore, a person skilled in the art based on the above description and the description of the claims, Various forms of coil components can be manufactured.

1: Coil parts 10: Insulators 11-15: Resin layers 21, 22: Strip conductors 30, 41, 42: Via conductors 40: Conductors 43: Columnar conductors 51, 52: External electrodes

Claims (9)

A coil component comprising an insulator made of resin, a coiled inner conductor provided in the insulator, and an external electrode electrically connected to the inner conductor,
A first layer made of a resin layer;
A second layer comprising a resin layer and at least one strip conductor on the first layer;
A third layer comprising a resin layer and at least two via conductors on the second layer;
A fourth layer comprising a resin layer, at least one strip conductor, and at least two via conductors on the third layer;
A fifth layer comprising a resin layer and at least two columnar conductors on the fourth layer;
An external electrode on the fifth layer;
The first to fifth resin layers integrally form an insulator, and the second to fifth layer strip conductors and columnar conductors constitute a coiled inner conductor,
A columnar conductor of the fourth layer is connected to the external electrode;
Coil parts.   The coil component according to claim 1, wherein an area of the fourth-layer strip-shaped conductor is larger than an area of the fourth-layer via-shaped conductor. The coil component of claim 1, wherein the area of the via conductor of the fourth layer is 50μm ² ~320μm ^2.   4. The coil component according to claim 3, wherein the maximum area of the fourth layer of strip-shaped conductors is greater than 1 and less than or equal to 100 times the minimum area of the fourth via conductor. The coil component of claim 1, wherein the area of the via conductor of the fourth layer is 20μm ² ~80μm ^2.   6. The coil component according to claim 5, wherein a maximum area of the fourth-layer strip-shaped conductor is greater than one and less than or equal to 50 times a minimum area of the fourth-layer via-shaped conductor.   The strip conductors of the second layer and the fourth layer, the columnar conductors of the fifth layer, the via conductors of the third layer and the fourth layer, and the external electrodes are formed using photolithography. The coil component according to any one of 6.   The coil component according to claim 1 or 7, wherein the external electrode is formed by forming a seed layer on the fifth layer and plating on the seed layer.   The insulator has a rectangular parallelepiped shape having a length L, a width W, and a height H, and the relationship L> H ≧ W is established for the L, W, and H, and the L is 0.2 to 0.4 mm. The coil component according to claim 4, 6 or 7, wherein the W is 0.1 to 0.2 mm and the H is 0.1 to 0.35 mm.