Laminated coil components

Abstract

The present invention relates to a laminated coil component. The laminated coil component (1) comprises: a laminate (10) formed by laminating a plurality of insulating layers (41) and having a coil (30) built therein; and a first external electrode (21) and a second external electrode (22) electrically connected to the coil (30), characterized in that the coil (30) is formed by electrically connecting a plurality of coil conductors (31) laminated together with the insulating layer (41), and the laminate (10) comprises: a first end face (11) facing each other in the direction in which the first external electrode (21) and the second external electrode (22) are opposite, that is, in the length direction; and A second end face (12), a first main face (13) and a second main face (14) facing each other in a height direction perpendicular to the length direction, and a first side face (15) and a second side face (16) facing each other in a width direction perpendicular to the length direction and the height direction, wherein the second main face (14) is a mounting face, the stacking direction of the stack (10) and the coil axis of the coil (30) are along the length direction, and the dimension of the stack (10) in the length direction, i.e., the length dimension L, and the dimension in the width direction, i.e., the width dimension W, are in a relationship of L / W<1.

Description

Technical Field

[0001] The present invention relates to a laminated coil component. Background Art

[0002] A stacked coil component, for example, as described in patent document 1, comprises: a stacked body formed by stacking a plurality of insulating layers; two external electrodes extending in the stacking direction of the stacked body and arranged on the sides of the stacked body opposite to each other; and a plurality of coil conductors stacked together with the insulating layers to form a coil, which overlap with each other and form a ring-shaped track when viewed from the stacking direction.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-254977

[0004] With the recent increase in communication speed and miniaturization of electronic devices, laminated coil components are required to have sufficient high-frequency characteristics in a high-frequency band (for example, a GHz band of 1 GHz or more).

[0005] However, the structure of the invention described in Patent Document 1 has a problem that the impedance characteristics in the high frequency region are insufficient.

[0006] There is also a problem that the laminated coil component has insufficient resistance to bending after being mounted. Summary of the invention

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laminated coil component having excellent high-frequency characteristics and high resistance to bending.

[0008] The stacked coil component of the present invention comprises: a stacked body formed by stacking multiple insulating layers and having a coil built inside; and a first external electrode and a second external electrode electrically connected to the coil. The stacked coil component is characterized in that the coil is formed by electrically connecting multiple coil conductors stacked together with the insulating layers. The stacked body has: a first end face and a second end face facing each other in the length direction, a first main face and a second main face facing each other in the height direction orthogonal to the length direction, and a first side face and a second side face facing each other in the width direction orthogonal to the length direction and the height direction, wherein the length direction is the direction in which the first external electrode and the second external electrode are opposite to each other, the second main face is the mounting face, the stacking direction of the stacked body and the coil axis of the coil are along the length direction, and the relationship between the length dimension L of the stacked body and the width dimension W is L / W<1.

[0009] According to the present invention, it is possible to provide a laminated coil component having excellent high frequency characteristics and high resistance to bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a perspective view schematically showing an example of the laminated coil component of the present invention.

[0011] Figure 2 It is a perspective view schematically showing an example of a laminated body constituting the laminated coil component of the present invention.

[0012] Figure 3 FIG. 1 is a LW cross-sectional view schematically showing the internal structure of the laminated coil component of the present invention.

[0013] Figure 4 This is a perspective view schematically showing an example of a laminated coil component for comparison.

[0014] Figure 5 This is a perspective view schematically showing an example of a laminated body constituting a laminated coil component for comparison.

[0015] Figure 6 It is a L′T′ cross-sectional view schematically showing the internal structure of a laminated coil component for comparison.

[0016] Figure 7 It is a cross-sectional view schematically showing the formation position of the gap portion between the insulating layer and the coil conductor.

[0017] Figure 8 This is an exploded view schematically showing a method for producing a laminated body by a printing lamination method.

[0018] Fig. 9 Graphs showing impedance characteristics of the laminated coil components of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0019] Hereinafter, the laminated coil component of the present invention will be described.

[0020] However, the present invention is not limited to the following embodiments, and can be applied with appropriate changes within the scope of the present invention. In addition, a structure in which two or more of the preferred structures described below are combined is also the present invention.

[0021] Figure 1 It is a perspective view schematically showing an example of the laminated coil component of the present invention.

[0022] Figure 2 FIG. 1 is a perspective view schematically showing an example of a laminated body constituting the laminated coil component of the present invention. Figure 2 In order to understand the structure of the coil of the laminated coil component, the inside is schematically shown through.

[0023] Figure 1 The laminated coil component 1 shown includes: a laminate 10, a first external electrode 21 and a second external electrode 22. The laminate 10 is a roughly rectangular parallelepiped with 6 faces. The structure of the laminate 10 will be described later. It is formed by stacking a plurality of insulating layers and having a coil built therein. The first external electrode 21 and the second external electrode 22 are electrically connected to the coil, respectively.

[0024] In the laminated coil component and laminate described in this specification, the direction in which the first external electrode and the second external electrode face each other is defined as the length direction, the direction perpendicular to the length direction is defined as the height direction, and the direction perpendicular to the length direction and the height direction is defined as the width direction.

[0025] exist Figure 1 and Figure 2 In FIG. 1 , the longitudinal direction, the width direction, and the height direction in the laminated coil component and the laminated body are indicated by double-headed arrows L, W, and T, respectively.

[0026] The length direction (L direction), the width direction (W direction), and the height direction (T direction) are orthogonal to each other.

[0027] The mounting surface of the laminated coil component 1 is a surface (LW surface) parallel to the longitudinal direction and the width direction.

[0028] Figure 1 and Figure 2 The stacked body 10 shown has: a first end face 11 and a second end face 12 facing each other in the length direction, a first main face 13 and a second main face 14 facing each other in the height direction orthogonal to the length direction, and a first side face 15 and a second side face 16 facing each other in the width direction orthogonal to the length direction and the height direction.

[0029] Although in Figure 1 and Figure 2 Although not shown in the figure, the laminate 10 is preferably rounded at corners and ridges. A corner is a portion where three surfaces of the laminate intersect, and a ridge is a portion where two surfaces of the laminate intersect.

[0030] like Figure 1 As shown, the first external electrode 21 covers the first end surface 11 of the stacked body 10 and extends from the first end surface 11 to cover a portion of the first main surface 13, a portion of the second main surface 14, a portion of the first side surface 15, and a portion of the second side surface 16. Figure 1 As shown, the second external electrode 22 covers the second end surface 12 of the stacked body 10 and extends from the second end surface 12 to cover a portion of the first main surface 13 , a portion of the second main surface 14 , a portion of the first side surface 15 , and a portion of the second side surface 16 .

[0031] The second main surface 14 serves as a mounting surface.

[0032] The coil is formed by electrically connecting a plurality of coil conductors stacked together with an insulating layer.

[0033] The direction in which the plurality of insulating layers are stacked, that is, the stacking direction of the stacked body is along the longitudinal direction. In addition, the coil axis of the coil is along the longitudinal direction.

[0034] Furthermore, it is preferable that the coil conductor and the first external electrode are electrically connected to the first side surface, and the coil conductor and the second external electrode are electrically connected to the second side surface.

[0035] exist Figure 2 3 shows that the coil conductor and the first external electrode 21 constituting the coil 30 are electrically connected on the first side 15, and the coil conductor and the second external electrode 22 are electrically connected on the second side 16. The conductor leading the coil 30 to the first side 15 is the lead conductor 35, and the conductor leading the coil 30 to the second side 16 is the lead conductor 36.

[0036] By changing the position where the coil conductor is led out to the outside of the laminate, the connection position between the coil conductor and the external electrode can be changed. The lead-out position may be changed to electrically connect the coil conductor and the external electrode on the main surface or end surface of the laminate.

[0037] In the laminated coil component of the present invention, the relationship between the length dimension L, which is the dimension in the longitudinal direction of the laminate, and the width dimension W, which is the dimension in the width direction, is L / W<1.

[0038] That is, the length dimension of the laminate is smaller than its width dimension.

[0039] In addition, regarding the relationship between the length dimension L and the width dimension W of the laminate, it is preferred that L / W ≤ 0.7.

[0040] In addition, it is preferred that the relationship between the length dimension L, which is the dimension in the longitudinal direction, and the height dimension T, which is the dimension in the height direction, of the laminate is L / T ≥ 0.7 and L / T ≤ 1.3.

[0041] In addition, L=T is also preferred.

[0042] The length dimension of the laminate is preferably 0.61 mm or more and preferably 0.91 mm or less.

[0043] The width dimension of the laminate is preferably 1.41 mm or more and preferably 1.71 mm or less.

[0044] The height dimension of the laminate is preferably 0.61 mm or more and preferably 0.91 mm or less.

[0045] Regarding the relationship between the length dimension L and the width dimension W of the laminate, if the length dimension L of the laminate is smaller than the width dimension W, the impedance characteristics in the high frequency region become good.

[0046] This is because it is possible to reduce the stray capacitance generated between the external electrode and the coil conductor inside the laminate. This will be described using the drawings.

[0047] Figure 3 FIG. 1 is a LW cross-sectional view schematically showing the internal structure of the laminated coil component of the present invention.

[0048] exist Figure 3 2 shows the second external electrode 22 and the coil conductors (31a, 31b, 31c, 31d, 31e) constituting the coil 30. The coil conductors 31a, 31b, 31c, 31d, 31e each represent one turn of the coil conductor. Figure 3 The illustration of the connection conductor that connects one turn of the coil conductor is omitted.

[0049] exist Figure 3 , the magnitude of stray capacitance generated between each coil conductor and the second external electrode 22 is schematically indicated by a circuit symbol of a capacitor.

[0050] When the stray capacitance generated between the coil conductor and the external electrode is large, the circuit symbol of the capacitor is represented as larger and thicker, and when the stray capacitance generated between the coil conductor and the external electrode is small, the circuit symbol of the capacitor is represented as smaller and thinner. In addition, when the stray capacitance generated between the coil conductor and the external electrode is small enough to be ignored, the circuit symbol of the capacitor is represented by a dotted line.

[0051] If the distance between the second external electrode and the coil conductor is short, the stray capacitance generated between the second external electrode and the coil conductor becomes larger. If the potential difference between the second external electrode and the coil conductor is large, the stray capacitance generated between the second external electrode and the coil conductor becomes larger.

[0052] Among the coil conductors, the coil conductor 31 e connected to the second external electrode 22 via the lead conductor 36 is close to the second external electrode 22 located on the second end surface 12 of the laminate, and stray capacitance is generated between the coil conductor 31 e and the second external electrode 22 .

[0053] On the other hand, the other coil conductors 31 a , 31 b , 31 c , and 31 d are closest to the second external electrode 22 that is present at the end of the first side surface 15 or the second side surface 16 .

[0054] Here, if the distance between the second external electrode 22 on the first side surface 15 on the left side of the figure and each coil conductor is considered, for the second external electrode 22, the distance between the second external electrode 22 and each coil conductor is shortest at the end point of the second external electrode indicated by the location 22a.

[0055] A small amount of stray capacitance is generated in the coil conductor 31d located on the side close to the second external electrode 22 in the width direction, but the distance between the coil conductor 31c located in the center in the width direction and the second external electrode 22 increases, so the stray capacitance decreases. Since the distance between the coil conductor 31b located on the side close to the first external electrode 21 in the width direction and the second external electrode 22 further increases, the stray capacitance further decreases. The coil conductor 31a connected to the first external electrode 21 through the lead conductor 35 has the largest distance from the second external electrode 22, so the stray capacitance is minimized.

[0056] As for the stray capacitance generated between the second external electrode 22 and the coil conductor, essentially only the stray capacitance between the coil conductor 31e and the second external electrode 22, and the stray capacitance between the coil conductor 31d and the second external electrode 22, represented by the circuit symbol of the capacitor with a solid line, need to be considered. The stray capacitance generated between the other coil conductors and the second external electrode 22 is small enough to be negligible.

[0057] In addition, with respect to the potentials in the coil conductors (31a, 31b, 31c, 31d, 31e) constituting the coil 30, the potential of the coil conductor 31e connected to the second external electrode 22 is close to the potential of the second external electrode 22, and the potential of the coil conductor 31a connected to the first external electrode 21 is close to the potential of the first external electrode 21.

[0058] As a result, the potential difference between the coil conductor 31 e and the second external electrode 22 is the smallest, and the potential difference between the coil conductor 31 d and the second external electrode 22 is the second smallest.

[0059] Since the stray capacitance decreases as the potential difference decreases, the stray capacitance between the coil conductor 31 e and the second external electrode 22 and the stray capacitance between the coil conductor 31 d and the second external electrode 22 are not so large.

[0060] As described above, the stray capacitance generated between the second external electrode 22 and the coil conductor is reduced as a whole.

[0061] The stray capacitance generated between the first external electrode 21 and the coil conductor is also reduced as a whole for the same reason.

[0062] Therefore, a laminated coil component in which the relationship between the length L and the width W of the laminate is L / W<1 can have good impedance characteristics in the high frequency region.

[0063] In order to compare with the laminated coil component of the present invention, the generation of stray capacitance in a laminated coil component having a different structure will be described.

[0064] Figure 4 This is a perspective view schematically showing an example of a laminated coil component for comparison.

[0065] Figure 5 This is a perspective view schematically showing an example of a laminated body constituting a laminated coil component for comparison.

[0066] Figure 4 The illustrated comparative laminated coil component 1' includes a laminate 10', a first external electrode 21', and a second external electrode 22'. The laminate 10' is in a substantially rectangular parallelepiped shape having six faces.

[0067] The direction in which the first external electrode 21 ′ and the second external electrode 22 ′ are opposite is the length direction (L′ direction), the direction perpendicular to the length direction is the height direction (T′ direction), and the direction perpendicular to the length direction and the height direction is the width direction (W′ direction).

[0068] exist Figure 4 and Figure 5 In FIG. 1 , the longitudinal direction, the width direction, and the height direction of the laminated coil component and the laminated body are indicated by double-headed arrows L′, W′, and T′, respectively.

[0069] The mounting surface of the laminated coil component 1' is a surface (L'W' surface) parallel to the longitudinal direction and the width direction.

[0070] Figure 4 and Figure 5 The stacked body 10′ shown has: a first end face 11′ and a second end face 12′ facing each other in the length direction, a first main face 13′ and a second main face 14′ facing each other in the height direction orthogonal to the length direction, and a first side face 15′ and a second side face 16′ facing each other in the width direction orthogonal to the length direction and the height direction.

[0071] like Figure 4 As shown, the first external electrode 21' covers the first end surface 11' of the stacked body 10', and extends from the first end surface 11' to cover a portion of the first main surface 13', a portion of the second main surface 14', a portion of the first side surface 15', and a portion of the second side surface 16'. Figure 4As shown, the second external electrode 22' covers the second end surface 12' of the stacked body 10' and extends from the second end surface 12' to cover a portion of the first main surface 13', a portion of the second main surface 14', a portion of the first side surface 15', and a portion of the second side surface 16'.

[0072] The second main surface 14 ′ serves as a mounting surface.

[0073] In the comparative laminated coil component 1', the relationship between the length dimension L', which is the dimension in the longitudinal direction of the laminate, and the width dimension W', which is the dimension in the width direction, is L' / W'>1.

[0074] That is, the length dimension of the laminate is greater than its width dimension.

[0075] In such cases, use Figure 6 The stray capacitance generated between the external electrode and the coil conductor inside the laminated body will be described.

[0076] Figure 6 It is a L′T′ cross-sectional view schematically showing the internal structure of a laminated coil component for comparison.

[0077] Figure 6 The graphical form of Figure 3 Similarly, the magnitude of stray capacitance generated between each coil conductor and the second external electrode 22 ′ is indicated by a circuit symbol of a capacitor.

[0078] Among the coil conductors, each of the coil conductors 31a′, 31b′, 31c′, 31d′, except for the coil conductor 31e′ connected to the second external electrode 22′ via the lead conductor 36′, is at the same distance from the second external electrode 22′, and the distance between the coil conductors and the second external electrode 22′ is relatively close, so that a non-negligible stray capacitance is generated between each coil conductor and the second external electrode 22′.

[0079] Furthermore, since the potential of the coil conductor 31a' connected to the first external electrode 21' via the lead conductor 35' is close to the potential of the first external electrode 21', the potential difference between the coil conductor 31a' and the second external electrode 22' is quite large. Therefore, the stray capacitance between the coil conductor 31a' and the second external electrode 22' is quite large.

[0080] Similarly, since the potential difference between the coil conductor 31b' and the second external electrode 22' is large, the stray capacitance between the coil conductor 31b' and the second external electrode 22' increases. In addition, since the potential difference between the coil conductor 31c' and the second external electrode 22' is slightly large, the stray capacitance between the coil conductor 31c' and the second external electrode 22' increases slightly.

[0081] As described above, in the comparative laminated coil component 1 ′, since there is a coil conductor having a large stray capacitance generated between the second external electrode 22 ′ and the coil conductor, the stray capacitance generated between the second external electrode 22 ′ and the coil conductor increases as a whole.

[0082] The stray capacitance generated between the first external electrode 21 ′ and the coil conductor also increases as a whole for the same reason.

[0083] Therefore, the impedance characteristics in the high frequency region of the laminated coil component in which the relationship between the length dimension L' of the laminated body and the width dimension W', which is the dimension in the width direction, is L' / W'>1 are insufficient.

[0084] Furthermore, the laminated coil component of the present invention is excellent in resistance to bending of the laminated coil component after the laminated coil component is mounted.

[0085] As the force applied to the laminated coil component when the substrate on which the laminated coil component is mounted is bent, it is assumed that the force is applied by three-point bending using the mounting locations of the first external electrode and the second external electrode as fulcrums at both ends.

[0086] In the laminated coil component of the present invention, the length dimension L of the laminate is smaller than the width dimension W, so the distance between the mounting position of the first external electrode and the mounting position of the second external electrode, that is, the distance between the fulcrums in the three-point bending, becomes smaller. The smaller the distance between the fulcrums, the smaller the force applied by the three-point bending, so that damage caused by the flexure of the laminated coil component is prevented, and a laminated coil component with high resistance to flexure can be obtained.

[0087] In contrast, Figure 4 In the laminated coil component 1' for comparison shown in the figure, since the length dimension L' of the laminate is larger than the width dimension W', the distance between the mounting part of the first external electrode and the mounting part of the second external electrode is larger, and the distance between the fulcrums in the three-point bending becomes larger. Since the distance between the fulcrums is larger, the force applied by the three-point bending is larger, so the laminated coil component is more likely to be damaged by bending.

[0088] In the laminated coil component of the present invention, it is preferable that a gap portion is provided between the insulating layer and the coil conductor.

[0089] Figure 7 It is a cross-sectional view schematically showing the formation position of the gap portion between the insulating layer and the coil conductor.

[0090] This cross-sectional view is equivalent to Figure 2 A cross section cut along a plane parallel to the LW plane.

[0091] exist Figure 72 shows a structure in which the coil conductor 31 and the insulating layer 42 are provided on the insulating layer 41 , and a gap 50 is provided between the insulating layer 41 and the coil conductor 31 .

[0092] The gap portion 50 is formed at a position slightly inward from the end portion of the coil conductor 31 .

[0093] Since the ceramic material (ferrite) constituting the insulating layer shrinks more than the metal material (silver) constituting the coil conductor during sintering, an extra force is applied between the ceramic material and the metal material, causing the inductance and impedance of the stacked coil component to deteriorate.

[0094] If a gap is provided between the insulating layer and the coil conductor, the contact between the ceramic material and the metal material is reduced, so that the force applied between the ceramic material and the metal material during sintering is relaxed.

[0095] Therefore, it is possible to suppress degradation of the inductance and impedance of the laminated coil component.

[0096] In the laminated coil component of the present invention, the number of turns of the coil is preferably 2 or more and 10 or less.

[0097] The length of the laminated coil component is preferably not less than 0.65 mm and preferably not more than 0.95 mm.

[0098] The width of the laminated coil component is preferably not less than 1.45 mm and preferably not more than 1.75 mm.

[0099] The height of the laminated coil component is preferably not less than 0.65 mm and preferably not more than 0.95 mm.

[0100] Next, an example of a method for manufacturing the laminated coil component according to the present embodiment will be described.

[0101] Hereinafter, a method for producing a laminated body by a printing lamination method will be described.

[0102] The printing lamination method is a method of forming a coil conductor extending in the lamination direction of a laminated body by printing and laminating a conductor paste and a ceramic paste.

[0103] This method is different from the method of producing a sheet having via-hole conductors in the sheet by laser drilling holes in the sheet and filling the holes with a conductor paste, and then laminating a plurality of such sheets.

[0104] Figure 8 This is an exploded view schematically showing a method for producing a laminated body by a printing lamination method.

[0105] exist Figure 8 2 shows the layer structure constituting the laminated body produced by the printing lamination method.

[0106] In the printing lamination method, Figure 8 Based on the outer layer 100 as the insulating layer shown at the bottom, the conductor paste and the ceramic paste are printed in sequence to obtain the state shown in the upper direction of the drawing.

[0107] Ceramic paste is a material that becomes an insulating layer by firing.

[0108] Figure 8 The layers shown represent the top surface state after printing, not the state of each layer. Figure 8 The layers shown are stacked.

[0109] First, a ceramic paste, a conductor paste, and a resin paste are prepared as materials.

[0110] As the ceramic paste, ferrite paste is preferably used.

[0111] As the ferrite paste, it is preferred to use a ferrite material composed of 40 mol% to 49.5 mol% of Fe converted to Fe2O3, 5 mol% to 35 mol% of Zn converted to ZnO, 4 mol% to 12 mol% of Cu converted to CuO, and 8 mol% to 42 mol% of Ni converted to NiO. The above materials may also contain trace additives (including inevitable impurities) such as Bi, Sn, Mn, and Co.

[0112] As a method for preparing the ceramic paste, for example, the following method is mentioned.

[0113] Fe2O3, ZnO, CuO, NiO and additives as needed are weighed to obtain a specified composition, put into a ball mill, wet-mixed and crushed, discharged, evaporated and dried, and calcined at a temperature of 700°C to 800°C to obtain a calcined powder.

[0114] Predetermined amounts of solvent (ketone solvent, etc.), resin (polyvinyl acetal, etc.) and plasticizer (alkyd plasticizer, etc.) are added to the calcined powder, kneaded in a planetary mixer, and then dispersed in a three-roll mill to prepare a ferrite paste.

[0115] As the conductor paste, a paste containing silver as a conductive material is preferably used.

[0116] As a method for preparing the conductor paste, for example, the following method is mentioned.

[0117] Silver powder is prepared, and a predetermined amount of solvent (such as eugenol), resin (such as ethyl cellulose), and dispersant are added, kneaded in a planetary mixer, and then dispersed in a three-roll mill to prepare a conductor paste.

[0118] The resin paste is a paste for forming a resin layer between the ceramic paste and the conductor paste, and the resin layer is burned off after firing to form a gap.

[0119] As a method for preparing the resin paste, for example, the following method is mentioned.

[0120] The resin paste is prepared by making the solvent (isophorone or the like) contain the resin (acrylic resin or the like) which is burned off during firing.

[0121] Since printing and lamination are performed from the bottom to the top of the drawing, the description will be given in this order.

[0122] First, a thermal release sheet and a base film are stacked on a metal plate, and a ceramic paste is printed a predetermined number of times to prepare an outer layer.

[0123] As the base film, a PET (polyethylene terephthalate) film can be preferably used.

[0124] exist Figure 8 The outer layer 100 is shown at the bottom.

[0125] Next, a resin paste is printed on the outer layer 100 to form a resin layer 150 so as to form Figure 8 The pattern shown second from the bottom.

[0126] The pattern of the resin layer 150 is substantially the same as the pattern of the coil conductor 31 to be formed later, and the line width of the resin layer 150 is preferably set to be slightly smaller than the line width of the coil conductor 31 .

[0127] Next, the conductor paste is printed to form the coil conductor 31 so as to become Figure 8 The lead conductor 36 is formed at the same time.

[0128] The conductive paste is formed so as to cover the resin layer 150 .

[0129] Next, ceramic paste is printed in the region where the lead conductor 36 and the coil conductor 31 are not formed to form the insulating layer 42a. The thickness of the insulating layer 42a is substantially the same as the thickness of the lead conductor 36 and the coil conductor 31.

[0130] Figure 8 The fourth pattern from the bottom shows the upper surface after the insulating layer 42a is formed.

[0131] Then, a part of the coil conductor 31 is exposed, and a ceramic paste is printed on the other region to form the insulating layer 42 b .

[0132] Figure 8 The fifth pattern from the bottom shows the upper surface after the insulating layer 42b is formed.

[0133] Next, a conductor paste is filled to form a connection conductor 33 for connecting turns of the coil so as to be connected to a part of the coil conductor 31 that is partially exposed.

[0134] Figure 8 The sixth pattern from the bottom shows the upper surface after the connection conductor 33 is formed.

[0135] Next, a resin paste is printed to form a resin layer 150 so as to become Figure 8 The pattern shown is the seventh from the bottom.

[0136] The pattern of the resin layer 150 is substantially the same as the pattern of the coil conductor 31 to be formed later, and the line width of the resin layer 150 is preferably set to be slightly smaller than the line width of the coil conductor 31 .

[0137] In addition, the resin layer 150 is formed so as not to cover the upper surface of the connection conductor 33 .

[0138] Next, the conductor paste is printed to form the coil conductor 31 so as to become Figure 8 The height difference between the resin layer 150 and the connection conductor 33 is filled with a conductor paste, so that the coil conductor 31 and the connection conductor 33 are electrically connected.

[0139] Thereafter, the steps of forming an insulating layer - forming a connecting conductor - forming a resin layer - forming a coil conductor - ... are repeated to produce a laminated body.

[0140] Finally, the conductor paste is printed to form the coil conductor 31 and the lead conductor 35 so as to form Figure 8 The pattern shown second from the top.

[0141] Furthermore, the ceramic paste is printed a predetermined number of times to form the outer layer 100 so as to cover the entire lead conductor 35 and the coil conductor 31 .

[0142] Next, after being mounted on a metal plate and pressed together and then cooled, the metal plate and the base film are peeled off in this order to obtain an aggregate (laminated body block) having a plurality of elements having the above-described pattern provided on one surface.

[0143] The stacked body block is cut by a dicing machine or the like to be separated into individual components.

[0144] This element corresponds to a laminated coil component.

[0145] The obtained element is subjected to a barrel grinding process, thereby cutting the corners of the element and forming a roundness. The barrel grinding process can be performed on the unfired element or on the fired laminate. In addition, the barrel grinding process can be either a dry process or a wet process. The barrel grinding process can be a method of rubbing the elements against each other or a method of barrel grinding the elements together with a medium.

[0146] After the barrel grinding treatment, the element is fired at a temperature of 910° C. or higher and 930° C. or lower to obtain a laminated body.

[0147] By firing the element, the resin layer is burned off, and a gap is formed between the insulating layer and the coil conductor (see Figure 7 ).

[0148] After the firing, a paste containing a metal is applied to the laminate and fired to form a base electrode.

[0149] Next, electroplating is performed to sequentially form a Ni film and a Sn film on the base electrode, thereby forming a first external electrode and a second external electrode, and a laminated coil component can be obtained.

[0150] The external electrodes are formed at positions Figure 1 Position as shown.

[0151] The external electrodes are formed with reference to the positions where the connection conductors are exposed from the laminate so as to become Figure 1 The position relationship shown.

[0152] The direction in which the laminated body has a larger dimension is referred to as the width direction (W direction), and the stacking direction of the laminated body and the direction of the coil axis are referred to as the length direction (L direction).

[0153] The surfaces facing each other in the length direction are the first end surface and the second end surface. The first external electrode is formed so as to cover the first end surface, and the second external electrode is formed so as to cover the second end surface.

[0154] The first external electrode is electrically connected to the coil conductor on the first side surface, and the second external electrode is electrically connected to the coil conductor on the second side surface.

[0155] Example

[0156] Hereinafter, an embodiment that more specifically discloses the laminated coil component of the present invention will be described. However, the present invention is not limited to only this embodiment.

[0157] [Example 1]

[0158] <Preparation of ceramic paste>

[0159] Fe2O3, ZnO, CuO, NiO and additives as needed are weighed to obtain a specified composition, put into a ball mill, wet-mixed and pulverized, discharged, evaporated and dried, and calcined at 750°C to obtain a calcined powder.

[0160] Predetermined amounts of solvent (ketone solvent, etc.), resin (polyvinyl acetal, etc.) and plasticizer (alkyd plasticizer, etc.) are added to the calcined powder, kneaded in a planetary mixer, and then dispersed in a three-roll mill to prepare a ferrite paste.

[0161] The ferrite paste contains a ferrite material composed of 45 mol % of Fe in terms of Fe2O3, 30 mol % of Zn in terms of ZnO, 10 mol % of Cu in terms of CuO, and 15 mol % of Ni in terms of NiO.

[0162] <Preparation of Conductor Paste>

[0163] Silver powder is prepared, and a predetermined amount of solvent (eugenol, etc.), resin (ethyl cellulose, etc.) and dispersant are added, kneaded in a planetary mixer, and then dispersed in a three-roll mill to prepare a conductor paste.

[0164] <Preparation of resin paste>

[0165] A resin paste is prepared by adding an acrylic resin to a solvent (isophorone).

[0166] <Production of laminated body>

[0167] pass Figure 8 The laminate is made using a printing lamination method in the order shown.

[0168] The produced laminated body has a gap between the insulating layer and the coil conductor.

[0169] The laminate is in the shape of a rectangular parallelepiped having one direction in which the dimension is larger and two directions in which the dimensions are smaller and the dimensions are the same.

[0170] The direction of the larger dimension of the laminate is defined as the width direction (W direction), the stacking direction of the laminate and the direction of the coil axis are defined as the length direction (L direction), and the direction perpendicular to the width direction and the length direction is defined as the height direction (T direction).

[0171] Surfaces facing each other in the longitudinal direction are referred to as a first end surface and a second end surface.

[0172] Surfaces facing each other in the width direction are referred to as first side surfaces and second side surfaces, and surfaces facing each other in the height direction are referred to as first principal surfaces and second principal surfaces.

[0173] <Formation of external electrodes>

[0174] A paste containing metal and glass is applied to the first end surface and the second end surface of the stacked body and then baked to form a base electrode.

[0175] Next, electroplating is performed to sequentially form a Ni film and a Sn film on the base electrode.

[0176] The first external electrode is formed so as to cover the first end surface, and the second external electrode is formed so as to cover the second end surface, thereby obtaining a laminated coil component.

[0177] The shape of the laminated coil component is Figure 1 In the shape shown, the dimensions of the laminate are L=0.8 mm, W=1.6 mm, and T=0.8 mm.

[0178] [Comparative Example 1]

[0179] The laminated coil component was manufactured in the same manner as that manufactured in Example 1 except that the location where the external electrodes were formed was changed.

[0180] The shape of the laminated coil component is Figure 4 In the shape shown, the dimensions of the laminate are L=1.6 mm, W=0.8 mm, and T=0.8 mm.

[0181] The laminate itself is the same as that of Example 1, but the surface on which the external electrodes are formed is different, so the length direction and the width direction are opposite. The external electrodes are formed on the surface with a size of 0.8 mm × 0.8 mm, and the surface on which the external electrodes are formed becomes the first end surface and the second end surface. Since the direction in which the first end surface and the second end surface face each other is the length direction, the length dimension L becomes 1.6 mm.

[0182] [evaluate]

[0183] The laminated coil components of Example 1 and Comparative Example 1 were evaluated as follows.

[0184] <Impedance measurement>

[0185] The impedance characteristics of the laminated coil components of Example 1 and Comparative Example 1 were measured at 1 MHz to 1000 MHz using an impedance analyzer (Model E4991A) manufactured by Agilent Technologies, Inc.

[0186] Fig. 9 Graphs showing impedance characteristics of the laminated coil components of Example 1 and Comparative Example 1.

[0187] In Example 1, the peak of the impedance shifts to the high-frequency side by about 100 MHz compared to Comparative Example 1, and it is found that the laminated coil of Example 1 is excellent in high-frequency characteristics.

[0188] <Simulation of flexural stress>

[0189] The maximum stress (flexural stress) applied to the laminated coil component when the laminated coil component is mounted on a substrate was evaluated by simulation.

[0190] Specifically, evaluation was performed at an ambient temperature of 125° C. using finite element analysis software (Femtet (registered trademark) manufactured by Murata Software Co., Ltd.) based on the thermal expansion coefficients of the laminated coil component and the mounting substrate.

[0191] A simulation was conducted by mounting a laminated coil component at the center of a mounting substrate having a size of 100 mm×40 mm and a thickness of 0.8 mm and applying a deflection of 3 mm.

[0192] The maximum stress generated in the laminated coil component was evaluated to be 808 MPa in Comparative Example 1 and 602 MPa in Example 1. It was found that the laminated coil component of Example 1 could reduce the bending stress by about 25%.

[0193] Description of Reference Numerals

[0194] 1…stacked coil component; 10…stacked body; 11…first end face; 12…second end face; 13…first principal face; 14…second principal face; 15…first side face; 16…second side face; 21…first external electrode; 22…second external electrode; 22a…end point of second external electrode; 30…coil; 31, 31a, 31b, 31c, 31d, 31e…coil conductor; 33…connecting conductor; 35…lead-out conductor connected to the first external electrode; 36…lead-out conductor connected to the second external electrode; 41, 42…insulating layer; 50…gap portion; 100…outer layer; 150…resin layer.

Claims

1. A laminated coil component, characterized in that: The laminated coil component comprises: a laminated body formed by laminating a plurality of insulating layers and having a coil built therein; and a first external electrode and a second external electrode electrically connected to the coil. The coil is formed by electrically connecting a plurality of coil conductors stacked together with the insulating layer. The number of coils built into the above-mentioned laminate is one, The stacked body comprises: a first end face and a second end face facing each other in a length direction, a first main face and a second main face facing each other in a height direction perpendicular to the length direction, and a first side face and a second side face facing each other in a width direction perpendicular to the length direction and the height direction, wherein the length direction is a direction in which the first external electrode and the second external electrode are opposite to each other, The second main surface is a mounting surface. The stacking direction of the stacked body and the coil axis of the coil are along the length direction. The relationship between the length dimension L, which is a dimension in the longitudinal direction, and the width dimension W, which is a dimension in the width direction, of the laminate is L / W<1.

2. The laminated coil component according to claim 1, wherein: The relationship between the length dimension L, which is a dimension in the longitudinal direction, and the width dimension W, which is a dimension in the width direction, of the laminate is L / W≤0.

7.

3. The laminated coil component according to claim 1 or 2, wherein: The relationship between the length dimension L, which is a dimension in the longitudinal direction, and the height dimension T, which is a dimension in the height direction, of the laminate is L / T≥0.7 and L / T≤1.

3.

4. The laminated coil component according to any one of claims 1 to 3, wherein: The coil conductor and the first external electrode are electrically connected at the first side surface. The coil conductor and the second external electrode are electrically connected to each other at the second side surface.

5. The laminated coil component according to any one of claims 1 to 4, wherein: A gap portion is provided between the insulating layer and the coil conductor.

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