JP7517509B2 - Multilayer coil parts - Google Patents

Description

The present invention relates to a multilayer coil component.

In response to the recent increase in communication speed and miniaturization of electrical devices, multilayer inductors are required to have sufficient high-frequency characteristics in high-frequency bands (for example, GHz bands of 50 GHz or higher).
As an example of a multilayer coil component, Patent Document 1 discloses a multilayer inductor in which the lamination direction of insulating members and the axial direction of the coil are parallel to the mounting surface.

Japanese Patent Application Publication No. 9-129447

In the multilayer inductor of Patent Document 1, the external electrodes are formed on both ends of the laminate by means of sputtering, vacuum deposition, or the like. However, the multilayer inductor described in Patent Document 1 may not have sufficient high-frequency characteristics in the GHz band of 50 GHz or higher.

The present invention has been made to solve the above problems, and aims to provide a multilayer coil component with excellent high-frequency characteristics.

The laminated coil component of the present invention comprises a laminate formed by stacking a plurality of insulating layers in the longitudinal direction and incorporating a coil therein, and a first external electrode and a second external electrode electrically connected to the coil, the coil being formed by electrically connecting a plurality of coil conductors stacked in the longitudinal direction together with the insulating layers, the laminate having a first end face and a second end face opposing each other in the longitudinal direction, a first main surface and a second main surface opposing each other in a height direction perpendicular to the longitudinal direction, and a first side surface and a second side surface opposing each other in a width direction perpendicular to the longitudinal direction and the height direction, the first external electrode being the first The first external electrode covers at least a portion of the end face, the stacking direction of the laminate and the coil axis direction of the coil are parallel to the first main surface, the distance between adjacent coil conductors in the stacking direction is 4 μm or more and 8 μm or less, the coil conductor has a line portion and a land portion disposed at an end of the line portion, the land portions of the coil conductors adjacent in the stacking direction are connected to each other via a via conductor, the width of the line portion is 30 μm or more and 50 μm or less, and the inner diameter of the coil conductor is 50 μm or more and 100 μm or less.

The present invention provides a multilayer coil component with excellent high-frequency characteristics.

FIG. 1 is a perspective view showing a typical example of a multilayer coil component according to the present invention. 2(a) is a side view of the laminated coil component shown in FIG. 1, FIG. 2(b) is a front view of the laminated coil component shown in FIG. 1, and FIG. 2(c) is a bottom view of the laminated coil component shown in FIG. 1. FIG. 3 is a cross-sectional view that illustrates an example of the multilayer coil component of the present invention. FIG. 4 is an exploded perspective view showing the insulating layers constituting the multilayer coil component shown in FIG. FIG. 5 is an exploded plan view showing the insulating layers constituting the multilayer coil component shown in FIG. FIG. 6 is a plan view showing a schematic diagram of a repeating shape of a coil conductor. FIG. 7 is a perspective view that illustrates a schematic diagram of another example of the multilayer coil component of the present invention. 8(a) is a side view of the laminated coil component shown in FIG. 7, FIG. 8(b) is a front view of the laminated coil component shown in FIG. 7, and FIG. 8(c) is a bottom view of the laminated coil component shown in FIG. FIG. 9 is a diagram showing a schematic diagram of a method for measuring the transmission coefficient S21. FIG. 10 is a graph showing the transmission coefficient S21 of Samples 1 to 5. FIG. 11 is a graph showing the transmission coefficient S21 of Samples 6 to 10. FIG. 12 is a graph showing the transmission coefficient S21 of Samples 11 to 15. FIG. 13 is a graph showing the transmission coefficient S21 of samples 3 and 16.

The laminated coil component of the present invention will be described below.
However, the present invention is not limited to the following embodiments, and can be modified as appropriate within the scope of the present invention. Note that the present invention also includes a combination of two or more of the individual preferable configurations described below.

FIG. 1 is a perspective view showing a typical example of a multilayer coil component according to the present invention.
2(a) is a side view of the laminated coil component shown in FIG. 1, FIG. 2(b) is a front view of the laminated coil component shown in FIG. 1, and FIG. 2(c) is a bottom view of the laminated coil component shown in FIG. 1.

The laminated coil component 1 shown in Figures 1, 2(a), 2(b) and 2(c) comprises a laminate 10, a first external electrode 21 and a second external electrode 22. The laminate 10 is a roughly rectangular parallelepiped shape having six sides. The configuration of the laminate 10 will be described later, but it is made up of multiple insulating layers stacked in the length direction and has a coil built in. The first external electrode 21 and the second external electrode 22 are each electrically connected to the coil.

In the laminated coil component and laminate of the present invention, the length direction, height direction, and width direction are the x direction, y direction, and z direction in Figure 1. Here, the length direction (x direction), height direction (y direction), and width direction (z direction) are mutually perpendicular.

As shown in Figures 1, 2(a), 2(b) and 2(c), the laminate 10 has a first end face 11 and a second end face 12 that face each other in the length direction (x direction), a first main surface 13 and a second main surface 14 that face each other in the height direction (y direction) perpendicular to the length direction, and a first side surface 15 and a second side surface 16 that face each other in the width direction (z direction) perpendicular to the length and height directions.

Although not shown in FIG. 1, it is preferable that the corners and ridges of the laminate 10 are rounded. 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.

As shown in Figures 1, 2(a), 2(b) and 2(c), the first external electrode 21 covers the entire first end face 11 of the laminate 10 and extends from the first end face 11 to cover part of the first main surface 13, part of the second main surface 14, part of the first side surface 15, and part of the second side surface 16.
In addition, the second external electrode 22 covers the entire second end face 12 of the laminate 10, and extends from the second end face 12 to cover part of the first main surface 13, part of the second main surface 14, part of the first side surface 15, and part of the second side surface 16.

Since the first external electrode 21 and the second external electrode 22 are arranged as described above, when the laminated coil component 1 is mounted on a substrate, any one of the first main surface 13, the second main surface 14, the first side surface 15, and the second side surface 16 of the laminate 10 becomes the mounting surface.

The size of the laminated coil component of the present invention is not particularly limited, but 0603 size is preferable.

When the laminated coil component of the present invention is a 0603 size, the length of the laminate (the length indicated by the double arrow _L1 in FIG. 2( a)) is preferably 0.63 mm or less, and is preferably 0.57 mm or more, and is more preferably 0.60 mm (600 μm) or less and 0.56 mm (560 μm) or more.
When the laminated coil component of the present invention is 0603 size, the width of the laminate (the length indicated by the double arrow _W1 in FIG. 2(c)) is preferably 0.33 mm or less and preferably 0.27 mm or more.
When the laminated coil component of the present invention is 0603 size, the height of the laminate (the length indicated by the double arrow _T1 in FIG. 2(b)) is preferably 0.33 mm or less and preferably 0.27 mm or more.

When the laminated coil component of the present invention is of 0603 size, the length of the laminated coil component (the length indicated by the double-headed arrow _L2 in FIG. 2(a)) is preferably 0.63 mm or less and is preferably 0.57 mm or more.
When the laminated coil component of the present invention is of 0603 size, the width of the laminated coil component (the length indicated by the double-headed arrow _W2 in FIG. 2(c)) is preferably 0.33 mm or less and is preferably 0.27 mm or more.
When the laminated coil component of the present invention has a size of 0603, the height of the laminated coil component (the length indicated by the double-headed arrow _T2 in FIG. 2(b)) is preferably 0.33 mm or less and is preferably 0.27 mm or more.

When the laminated coil component of the present invention is 0603 size, the length of the first external electrode (the length indicated by the double arrow E1 in FIG. 2(c)) covering the first main surface of the laminate is preferably 0.12 mm or more and 0.22 mm or less. Similarly, the length of the second external electrode (the length indicated by the double arrow _E1 in FIG. 2(c)) covering the first main surface of the laminate is preferably 0.12 mm or more and 0.22 mm or less.
In addition, when the length of the portion of the first external electrode covering the first main surface of the laminate and the length of the portion of the second external electrode covering the first main surface of the laminate are not constant, it is preferable that the length of the longest portion is within the above range.

The coil built into the laminate constituting the multilayer coil component of the present invention will now be described.
The coil is formed by electrically connecting a plurality of coil conductors which are laminated in the longitudinal direction with insulating layers.

FIG. 3 is a cross-sectional view showing an example of the laminated coil component of the present invention, FIG. 4 is an exploded perspective view showing an insulating layer constituting the laminated coil component shown in FIG. 3, and FIG. 5 is an exploded plan view showing an insulating layer constituting the laminated coil component shown in FIG. 3.
3 is a schematic diagram showing the insulating layers, the coil conductors, the connecting conductors, and the stacking direction of the laminate, and does not strictly represent the actual shapes, connections, etc. For example, the coil conductors are connected through via conductors.

As shown in FIG. 3, the multilayer coil component 1 includes a laminate 10 incorporating a coil formed by electrically connecting a plurality of coil conductors 32 stacked together with insulating layers, and a first external electrode 21 and a second external electrode 22 electrically connected to the coil.
The laminate 10 has a region where the coil conductors are arranged and a region where the connecting conductors 41 or the connecting conductors 42 are arranged. The stacking direction of the laminate 10 and the axial direction of the coil (coil axis A is shown in FIG. 3 ) are parallel to the first main surface 13.

The dimension _L3 of the arrangement region of the coil conductor 32 in the stacking direction is preferably 85% to 95%, and more preferably 90% to 95%, of the length dimension _L1 of the laminate 10. When the dimension _L3 of the arrangement region of the coil conductor 32 in the stacking direction is 85% to 95% of the length dimension of the laminate 10, the length of the connecting conductor in the laminate is shortened, which reduces the stray capacitance and improves the high-frequency characteristics.

The distance _DC between adjacent coil conductors 32 in the stacking direction of the laminate 10 is 4 μm or more and 8 μm or less. When the distance _DC between adjacent coil conductors 32 in the stacking direction of the laminate 10 is 4 μm or more and 8 μm or less, the high-frequency characteristics are improved.
If the distance D _C between adjacent coil conductors in the stacking direction is less than 4 μm, the stray capacitance increases and the high-frequency characteristics deteriorate, whereas if the distance D _C between adjacent coil conductors in the stacking direction exceeds 8 μm, the inductance of the coil decreases.

As shown in Fig. 4 and Fig. 5, the laminate 10 has insulating layers 31a, 31b, 31c, and 31d as the insulating layer 31 in Fig. 3. The laminate 10 has insulating layers _35a1 , 35a2, 35a3, and _35a4 as the insulating layer 35a in Fig. 3. The laminate 10 has insulating layers _35b1 , _35b2 , _35b3 , and _35b4 as the insulating layer _35b in Fig. ₃ .

The coil 30 has coil conductors 32a, 32b, 32c, and 32d as the coil conductors 32 in FIG. 3.

Coil conductor 32a, coil conductor 32b, coil conductor 32c, and coil conductor 32d are arranged on the main surfaces of insulating layer 31a, insulating layer 31b, insulating layer 31c, and insulating layer 31d, respectively.

The length of coil conductor 32a, coil conductor 32b, coil conductor 32c, and coil conductor 32d is each 3/4 turn of coil 30. In other words, the number of coil conductor layers required to form the three turns of coil 30 is four. In laminate 10, coil conductor 32a, coil conductor 32b, coil conductor 32c, and coil conductor 32d are repeatedly layered as one unit (three turns).

The coil conductor 32a has a line portion 36a and a land portion 37a arranged at the end of the line portion 36a. The coil conductor 32b has a line portion 36b and a land portion 37b arranged at the end of the line portion 36b. The coil conductor 32c has a line portion 36c and a land portion 37c arranged at the end of the line portion 36c. The coil conductor 32d has a line portion 36d and a land portion 37d arranged at the end of the line portion 36d.

Via conductors 33a, 33b, 33c, and 33d are arranged in insulating layer 31a, insulating layer 31b, insulating layer 31c, and insulating layer 31d, respectively, so as to penetrate in the stacking direction.

The insulating layer 31a with the coil conductor 32a and the via conductor 33a, the insulating layer 31b with the coil conductor 32b and the via conductor 33b, the insulating layer 31c with the coil conductor 32c and the via conductor 33c, and the insulating layer 31d with the coil conductor 32d and the via conductor 33d are repeatedly stacked as one unit (the part surrounded by the dotted line in Figures 4 and 5). As a result, the land portion 37a of the coil conductor 32a, the land portion 37b of the coil conductor 32b, the land portion 37c of the coil conductor 32c, and the land portion 37d of the coil conductor 32d are connected via the via conductor 33a, the via conductor 33b, the via conductor 33c, and the via conductor 33d. In other words, the land portions of the coil conductors adjacent to each other in the stacking direction are connected to each other via the via conductors.

The above constitutes the solenoid coil 30 built into the laminate 10.

When viewed in a plane from the stacking direction, coil 30, which is composed of coil conductors 32a, 32b, 32c, and 32d, may be circular or polygonal. When coil 30 is polygonal from the stacking direction, the diameter of a circle equivalent to the area of the polygon is defined as the coil diameter of coil 30, and the axis passing through the center of gravity of the polygon and extending in the stacking direction is defined as the coil axis of coil 30.

When viewed in a plane from the stacking direction, it is preferable that the diameters of land portions 37a, 37b, 37c, and 37d are each larger than the line widths of line portions 36a, 36b, 36c, and 36d, as shown in FIG. 5.

When viewed in a plane from the stacking direction, land portion 37a, land portion 37b, land portion 37c, and land portion 37d may each be circular as shown in FIG. 5, or may be polygonal. When viewed in a plane from the stacking direction, if land portion 37a, land portion 37b, land portion 37c, and land portion 37d are polygonal, the diameter of the circle equivalent to the area of the polygon is defined as the diameter of each land portion.

The via conductors 33p are arranged so as to penetrate the insulating layers _35a1 , _35a2 , _35a3 , and _35a4 in the stacking direction. Land portions connected to the via conductors 33p may be arranged on the main surfaces of the insulating layers _35a1 , _35a2 , _35a3 , and _35a4 .

The insulating layer _35a1 with the via conductor 33p, the insulating layer _35a2 with the via conductor 33p, the insulating layer _35a3 with the via conductor 33p, and the insulating layer _35a4 with the via conductor 33p are laminated so as to overlap the coil conductor 32a and the insulating layer 31a with the via conductor 33a. As a result, the via conductors 33p are connected to each other to form a first connecting conductor 41, and the first connecting conductor 41 is exposed at the first end surface 11. As a result, the first external electrode 21 and the coil 30 are connected to each other via the first connecting conductor 41.

As described above, it is preferable that the first connecting conductor 41 connects the first external electrode 21 and the coil 30 in a straight line. When the first connecting conductor 41 connects the first external electrode 21 and the coil 30 in a straight line, this means that the via conductors 33p constituting the first connecting conductor 41 overlap each other when viewed in a plan view from the stacking direction, and the via conductors 33p do not have to be arranged in a strictly straight line.

The via conductor 33q is arranged to penetrate the insulating layer _35b1 , the insulating layer _35b2 , the insulating layer _35b3 , and the insulating layer _35b4 in the stacking direction. Land portions connected to the via conductor 33q may be arranged on the main surfaces of the insulating layer _35b1 , the insulating layer _35b2 , the insulating layer _35b3 , and the insulating layer _35b4 .

The insulating layer _35b1 with the via conductor 33q, the insulating layer _35b2 with the via conductor 33q, the insulating layer _35b3 with the via conductor 33q, and the insulating layer _35b4 with the via conductor 33q are laminated so as to overlap the coil conductor 32d and the insulating layer 31d with the via conductor 33d. As a result, the via conductors 33q are connected to each other to form the second connecting conductor 42, and the second connecting conductor 42 is exposed at the second end surface 12. As a result, the second external electrode 22 and the coil 30 (coil conductor 32d) are connected to each other via the second connecting conductor 42.

As described above, it is preferable that the second connecting conductor 42 connects the second external electrode 22 and the coil 30 in a straight line. When the second connecting conductor 42 connects the second external electrode 22 and the coil 30 in a straight line, this means that the via conductors 33q constituting the second connecting conductor 42 overlap each other when viewed in a plan view from the stacking direction, and the via conductors 33q do not have to be arranged in a strictly straight line.

Note that when a land portion is connected to each of the via conductors 33p constituting the first connecting conductor 41 and the via conductors 33q constituting the second connecting conductor 42, the shapes of the first connecting conductor 41 and the second connecting conductor 42 refer to the shapes excluding the land portions.

Figures 4 and 5 show an example in which the number of layers of the coil conductor to form three turns of the coil 30 is four, i.e., the repeating shape is a 3/4 turn shape, but the number of layers of the coil conductor to form one turn of the coil is not particularly limited.
For example, the number of laminations of the coil conductor to form one turn of the coil may be two, that is, the repeating shape may be a 1/2 turn shape.

When viewed in a plan view from the stacking direction, the coil conductors constituting the coil preferably overlap each other. Also, when viewed in a plan view from the stacking direction, the shape of the coil is preferably circular. Note that, when the coil includes a land portion, the shape excluding the land portion (i.e., the shape of the line portion) is the shape of the coil.
Furthermore, in the case where a land portion is connected to a via conductor constituting a connecting conductor, the shape excluding the land portion (i.e., the shape of the via conductor) is regarded as the shape of the connecting conductor.

Although the coil conductor shown in FIG. 4 has a shape in which the repeating pattern is circular, the coil conductor may have a repeating pattern in a polygonal shape such as a rectangle.
Furthermore, the repeating shape of the coil conductor may be a 1/2 turn shape instead of a 3/4 turn shape.

FIG. 6 is a plan view showing a schematic diagram of a repeating shape of a coil conductor.
As shown in FIG. 6, the repeating shape of the coil conductor 32 is a circle.
The inner diameter _Rc of the coil conductor 32 is 50 μm or more and 100 μm or less, and the width _Wc of the line portion constituting the coil conductor 32 is 30 μm or more and 50 μm or less.

By setting the distance between adjacent coil conductors in the stacking direction to 4 μm or more and 8 μm or more, setting the width of the line portion of the coil conductor to 30 μm or more and 50 μm or less, and setting the inner diameter of the coil conductor to 50 μm or more and 100 μm or more, the stray capacitance between adjacent coil conductors in the stacking direction is reduced, thereby improving high-frequency characteristics and enabling the transmission coefficient S21 at 50 GHz to be -1.2 dB or more.
When the transmission coefficient S21 of the multilayer coil component at 50 GHz is -1.2 dB or more, it can be suitably used in, for example, a bias-tee circuit in an optical communication circuit. The transmission coefficient S21 is determined from the ratio of the power of the transmitted signal to the power of the input signal. The transmission coefficient S21 for each frequency is determined, for example, by using a network analyzer. The transmission coefficient S21 is basically a dimensionless quantity, but is usually expressed in dB units by taking the common logarithm.

The width of the line portion is 30 μm or more and 50 μm or less, and more preferably 30 μm or more and 40 μm or less. If the line width of the line portion is smaller than 30 μm, the direct current resistance of the coil increases. If the line width of the line portion is larger than 50 μm, the electrostatic capacitance of the coil increases, and the high frequency characteristics of the laminated coil component decrease.
By setting the width of the line portion to be 30 μm or more and 40 μm or less, the transmission coefficient S21 of the multilayer coil component at 50 GHz can be set to be −1.0 dB or more.

The inner diameter of the coil conductor is 50 μm or more and 100 μm or less, and more preferably 50 μm or more and 80 μm or less.
If the inner diameter of the coil conductor is smaller than 50 μm, the inductance of the coil decreases, and if the inner diameter of the coil conductor is larger than 100 μm, the electrostatic capacitance of the coil increases, degrading the high-frequency characteristics of the multilayer coil component.
By setting the inner diameter of the coil conductor to be 50 μm or more and 80 μm or less, the transmission coefficient S21 of the multilayer coil component at 50 GHz can be set to be −1.0 dB or more.

The distance between adjacent coil conductors in the stacking direction is 4 μm or more and 8 μm or less, and preferably 5 μm or more and 7 μm or less.
By setting the distance between adjacent coil conductors in the stacking direction to 5 μm or more and 7 μm or less, the transmission coefficient S21 of the multilayer coil component at 50 GHz can be set to −1.0 dB or more.

When viewed in a plan view from the stacking direction, it is preferable that the outer periphery of the land portion of the coil conductor be in contact with the inner periphery of the line portion. This makes the area of the land portion located outside the outer periphery of the line portion sufficiently small, and the stray capacitance caused by the land portion is sufficiently small, thereby further improving the high-frequency characteristics of the stacked coil component.

The shape of the land portion when viewed in a planar view from the stacking direction may be circular or polygonal. If the shape of the land portion is polygonal, the diameter of the land portion is the diameter of a circle equivalent to the area of the polygon.

The thickness of the coil conductor is not particularly limited, but it is preferable that it be 3 μm or more and 6 μm or less.

The number of layers of the coil conductor is not particularly limited, but is preferably 40 or more and 60 or less.
If the number of layers of the coil conductor is less than 40, the stray capacitance increases and the transmission coefficient S21 decreases. On the other hand, if the number of layers of the coil conductor is more than 60, the direct current resistance (Rdc) increases.
By setting the number of laminations of the coil conductor to be 40 or more and 60 or less, the transmission coefficient S21 at 50 GHz can be improved.

In the multilayer coil component of the present invention, when viewed in a plan view from the stacking direction, it is preferable that the land portions are not located inside the inner peripheral edge of the line portions and partially overlap the line portions.
If the land portion is located inside the inner periphery of the line portion, the impedance may decrease.
In addition, when viewed in a plan view from the stacking direction, the diameter of the land portion is preferably 1.05 to 1.3 times the line width of the line portion.
If the diameter of the land portion is less than 1.05 times the line width of the line portion, the connection between the land portion and the via conductor may be insufficient, whereas if the diameter of the land portion is more than 1.3 times the line width of the line portion, the stray capacitance caused by the land portion increases, and the high frequency characteristics may deteriorate.

In this specification, the distance between adjacent coil conductors in the stacking direction is the shortest distance in the stacking direction between coil conductors connected through vias. Therefore, the distance between adjacent coil conductors in the stacking direction does not necessarily match the distance between coil conductors that generate stray capacitance.

In the multilayer coil component of the present invention, the mounting surface is not particularly limited, but it is preferable that the first main surface is the mounting surface.
When the first main surface is the mounting surface, it is preferable that the first external electrode extends to cover a portion of the first end face and a portion of the first main surface, and that the second external electrode extends to cover a portion of the second end face and a portion of the first main surface.

Examples of the shapes of the external electrodes when the first main surface is the mounting surface will be described with reference to Figs. 7, 8(a), 8(b) and 8(c).
FIG. 7 is a perspective view illustrating a schematic view of another example of the laminated coil component of the present invention, FIG. 8( a) is a side view of the laminated coil component shown in FIG. 7, FIG. 8( b) is a front view of the laminated coil component shown in FIG. 7, and FIG. 8( c) is a bottom view of the laminated coil component shown in FIG. 7.

The laminated coil component 2 shown in Figures 7, 8(a), 8(b), and 8(c) includes a laminate 10, a first external electrode 121, and a second external electrode 122. The configuration of the laminate 10 is the same as that of the laminate 10 constituting the laminated coil component 1 shown in Figures 1, 2(a), 2(b), and 2(c).

The first external electrode 121 is disposed so as to cover a portion of the first end face 11 of the laminate 10 as shown in Figs. 7 and 8(b), and to extend from the first end face 11 to cover a portion of the first main surface 13 as shown in Figs. 7 and 8(c). As shown in Fig. 8(b), the first external electrode 121 covers an area of the first end face 11 including a ridge portion intersecting with the first main surface 13, but may also extend from the first end face 11 to cover the second main surface 14.

In FIG. 8(b), the height of the first external electrode 121 in the portion covering the first end face 11 of the laminate 10 is constant, but the shape of the first external electrode 121 is not particularly limited as long as it covers a portion of the first end face 11 of the laminate 10. For example, in the first end face 11 of the laminate 10, the first external electrode 121 may have a mountain shape that becomes higher from the end toward the center. In FIG. 8(c), the length of the first external electrode 121 in the portion covering the first main surface 13 of the laminate 10 is constant, but the shape of the first external electrode 121 is not particularly limited as long as it covers a portion of the first main surface 13 of the laminate 10. For example, in the first main surface 13 of the laminate 10, the first external electrode 121 may have a mountain shape that becomes longer from the end toward the center.

As shown in Figs. 7 and 8(a), the first external electrode 121 may be arranged to extend from the first end face 11 and the first main face 13 and cover a part of the first side face 15 and a part of the second side face 16. In this case, as shown in Fig. 8(a), it is preferable that the first external electrode 121 in the part covering the first side face 15 and the second side face 16 is formed at an angle with respect to the ridge line portion intersecting with the first end face 11 and the ridge line portion intersecting with the first main face 13. Note that the first external electrode 121 does not have to be arranged to cover a part of the first side face 15 and a part of the second side face 16.

The second external electrode 122 is disposed so as to cover a portion of the second end face 12 of the laminate 10, and also extends from the second end face 12 to cover a portion of the first main face 13. Similar to the first external electrode 121, the second external electrode 122 covers a region of the second end face 12 that includes a ridge portion intersecting with the first main face 13.
Also, similar to the first external electrode 121, the second external electrode 122 may extend from the second end face 12 and cover 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.

Similar to the first external electrode 121, the shape of the second external electrode 122 is not particularly limited as long as it covers a portion of the second end surface 12 of the laminate 10. For example, on the second end surface 12 of the laminate 10, the second external electrode 122 may have an arched shape that becomes higher from the end toward the center. Also, as long as it covers a portion of the first main surface 13 of the laminate 10, the shape of the second external electrode 122 is not particularly limited. For example, on the first main surface 13 of the laminate 10, the second external electrode 122 may have an arched shape that becomes longer from the end toward the center.

Similar to the first external electrode 121, the second external electrode 122 may be arranged to extend from the second end face 12 and the first main face 13 and cover a part of the second main face 14, a part of the first side face 15, and a part of the second side face 16. In this case, it is preferable that the part of the second external electrode 122 covering the first side face 15 and the second side face 16 is formed at an angle with respect to the ridge line portion intersecting with the second end face 12 and the ridge line portion intersecting with the first main face 13. Note that the second external electrode 122 does not have to be arranged to cover a part of the second main face 14, a part of the first side face 15, and a part of the second side face 16.

Since the first external electrode 121 and the second external electrode 122 are arranged as described above, when the laminated coil component 2 is mounted on a substrate, the first main surface 13 of the laminate 10 becomes the mounting surface.

The height of the first external electrode (the length indicated by the double-headed arrow _E2 in FIG. 8(b)) in the portion covering the first end face of the laminate is preferably 0.10 mm or more and 0.20 mm or less. Similarly, the height of the second external electrode in the portion covering the second end face of the laminate is preferably 0.10 mm or more and 0.20 mm or less. In this case, the stray capacitance caused by the external electrodes can be reduced.
In addition, when the height of the first external electrode covering the first end face of the laminate and the height of the second external electrode covering the second end face of the laminate are not constant, it is preferable that the height of the highest part is within the above range.

The laminated coil components 2 shown in Figures 7, 8(a), 8(b), and 8(c) have a smaller area in which external electrodes are provided than the laminated coil components 1 shown in Figures 1, 2(a), 2(b), and 2(c), and therefore have a smaller stray capacitance than the laminated coil component 1 and can improve high-frequency characteristics.

When the shapes of the external electrodes shown in Figures 7, 8(a), 8(b) and 8(c) are adopted, it is preferable that the first and second connecting conductors are connected to the parts of the coil conductor closest to the first main surface. This makes it possible to reduce the height _E2 of the first and second external electrodes 121 and 122 covering the first and second end faces. By reducing the height _E2 , it is possible to reduce the stray capacitance between the external electrodes and the coil and improve the high frequency characteristics.

[Method of manufacturing laminated coil components]
An example of a method for producing the laminated coil component of the present invention will be described.

First, a ceramic green sheet that will later become an insulating layer is prepared. For example, an organic binder such as polyvinyl butyral resin, an organic solvent such as ethanol or toluene, a dispersant, etc. are added to a ferrite material and kneaded to form a slurry. Then, a ceramic green sheet with a thickness of about 10 to 25 μm is prepared by a method such as a doctor blade method.
When the thickness of the ceramic green sheets is about 10 to 25 μm, the distance between adjacent coil conductors in the stacking direction in the laminate can be easily adjusted to 4 μm or more and 8 μm or less.

For example, ferrite materials can be produced by the following method. First, oxide raw materials of iron, nickel, zinc, and copper are mixed and pre-fired at 800°C for 1 hour. The pre-fired material is then pulverized in a ball mill and dried to produce Ni-Zn-Cu ferrite material (mixed oxide powder) with an average particle size of approximately 2 μm.

When preparing a ceramic green sheet using a ferrite material, in order to obtain high _inductance , the composition of the ferrite material is preferably _Fe2O3 : 40 mol% or more and 49.5 mol% or less, ZnO: 5 mol% or more and 35 mol% or less, CuO: 4 mol% or more and 12 mol% or less, and the balance: NiO and trace additives (including unavoidable impurities).

In addition to the magnetic materials such as the ferrite materials mentioned above, the ceramic green sheets may be made of non-magnetic materials such as glass ceramic materials, or mixtures of magnetic and non-magnetic materials.

Next, a conductor pattern that will later become the coil conductor and the via conductor is formed on the ceramic green sheet. For example, first, a via hole with a diameter of about 20 μm or more and 30 μm or less is formed by performing laser processing on the ceramic green sheet. Then, a conductive paste such as silver paste is filled into the via hole to form a conductor pattern for the via conductor. Furthermore, a conductor pattern for the coil conductor with a thickness of about 11 μm is printed on the main surface of the ceramic green sheet using a conductive paste such as silver paste by a method such as screen printing. As the conductor pattern for the coil conductor, for example, a conductor pattern equivalent to the coil conductor as shown in FIG. 4 and FIG. 5 is printed.
At this time, the shape of the conductor pattern for the coil conductor is set so that the coil diameter of the obtained coil conductor is 50 μm or more and 100 μm or less, and the width of the line portion is 30 μm or more and 50 μm or less.

Then, by drying, a coil sheet is obtained having a configuration in which a conductor pattern for a coil conductor and a conductor pattern for a via conductor are formed on the ceramic green sheet. In the coil sheet, the conductor pattern for the coil conductor and the conductor pattern for the via conductor are connected to each other.

In addition to the coil sheet, a via sheet is also prepared, which has a via conductor pattern formed on a ceramic green sheet. The via conductor pattern of the via sheet is a conductor pattern that will later become the via conductor that constitutes the connecting conductor.

Next, the coil sheets are laminated in a predetermined order so that after singulation and firing, a coil having a coil axis parallel to the mounting surface is formed inside the laminate.
Furthermore, via sheets are laminated above and below the laminate of coil sheets.
The number of laminations of the coil sheet is preferably 40 or more and 60 or less.

Then, the laminate of the coil sheet and the via sheet is thermocompressed to obtain a bonded body, which is then cut to a predetermined chip size to obtain individual chips. The individual chips may be subjected to barrel polishing, for example, to round the corners and edges.

The individual chips are then subjected to a binder removal process and firing at a specified temperature and time to form a laminate (fired body) with a built-in coil inside. At this time, the conductor patterns for the coil conductors and the conductor patterns for the via conductors become coil conductors and via conductors, respectively, after firing. The coil is formed by connecting the coil conductors to each other via the via conductors. In addition, the stacking direction of the laminate and the coil axis direction of the coil are parallel to the mounting surface.

Next, the laminate is vertically immersed in a layer of conductive paste such as silver paste stretched to a predetermined thickness and baked to form a base electrode layer for the external electrodes on five surfaces of the laminate (end surfaces, both main surfaces, and both end surfaces).
In addition, by immersing the laminate at an angle into a layer of conductive paste such as silver paste stretched to a predetermined thickness and baking it, it is possible to form a base electrode layer for the external electrodes on the four surfaces (main surface, end surfaces, and both side surfaces) of the laminate.

Next, a nickel coating and a tin coating of a specified thickness are formed in sequence on the base electrode layer by plating. As a result, the external electrode is formed.

This is how the stacked coil component of the present invention is manufactured.

The following are examples that more specifically disclose the stacked coil component of the present invention. Note that the present invention is not limited to these examples.

[Sample Preparation]
(Sample 1)
(1) A ferrite material (calcined powder) having a predetermined composition was prepared.

(2) The calcined powder was added to a pot mill along with an organic binder (polyvinyl butyral resin) and an organic solvent (ethanol and toluene) along with PSZ balls, and the mixture was thoroughly mixed and ground in a wet manner to produce a magnetic slurry.

(3) The magnetic slurry was formed into a sheet using the doctor blade method, and then punched into rectangular shapes to produce multiple ceramic green sheets with a thickness of 12 μm.

(4) A conductive paste for the internal conductor was prepared, containing Ag powder and an organic vehicle.

(5) Preparation of via sheet: Via holes were formed by irradiating a laser at a predetermined position on a ceramic green sheet. The via holes were filled with conductive paste to form via conductors, and the conductive paste was screen-printed in a circular shape around the via conductors to form lands.

(6) Preparation of coil sheet Via holes were formed at predetermined positions of the ceramic green sheet and filled with conductive paste to form via conductors. Then, a coil conductor consisting of a land portion and a line portion was printed to obtain a coil sheet.

(7) These sheets were stacked in the order shown in Figures 4 and 5 so that the number of layers of the coil conductor was 56, and then heated and pressed, and cut into individual pieces with a dicer to produce a laminated molded body.

(8) The laminated compact was placed in a firing furnace, and subjected to a binder removal treatment at a temperature of 500° C. in an air atmosphere, and then fired at a temperature of 900° C. to produce a laminated body (fired).
The dimensions of 30 pieces of the resulting laminate were measured using a micrometer to obtain the average values, which were L = 0.60 mm, W = 0.30 mm, and T = 0.30 mm.

(9) A conductive paste for the external electrodes containing Ag powder and glass frit was poured into a coating film formation tank so that a coating film of a specified thickness was formed. The portions of the laminate where the external electrodes were to be formed were immersed in this coating film.

(10) After immersion, the substrate was baked at a temperature of about 800°C to form the base electrode for the external electrode.

(11) A Ni film and a Sn film were successively formed on the base electrode by electrolytic plating to form an external electrode.
As a result of the above, a laminated coil component (sample 1) was produced, which had external electrodes having the shapes shown in FIGS. 1, 2(a), 2(b), and 2(c) and the internal structure of the laminate as shown in FIGS. 3, 4, and 5.
In sample 1, the distance _Dc between adjacent coil conductors in the stacking direction was 4 μm, the coil inner radius _Rc was 100 μm, and the line portion width _Wc was 30 μm. The thickness of the coil conductor was 6 μm, and the dimension of the coil conductor arrangement area in the stacking direction was 93.3% of the length of the laminate.

(Measurement of transmission coefficient S21)
FIG. 9 is a diagram showing a schematic diagram of a method for measuring the transmission coefficient S21.
9 , a sample (the laminated coil component 1) was soldered to a measuring jig 60 provided with a signal path 61 and a ground conductor 62. The first external electrode 21 of the laminated coil component 1 was connected to the signal path 61, and the second external electrode 22 was connected to the ground conductor 62.

The power of the input signal to the sample and the transmitted signal was obtained using a network analyzer 63, and the transmission coefficient S21 was measured by changing the frequency. One end and the other end of the signal path 61 were connected to the network analyzer 63.
The measurement results are shown in Fig. 10, and the transmission coefficient S21 at 60 GHz is shown in Table 1. Fig. 10 is a graph showing the transmission coefficient S21 of the samples prepared in the examples. Note that the closer the transmission coefficient S21 is to 0 dB, the smaller the loss is.

(Samples 2 to 16)
Stacked coil components (samples 2 to 16) were produced and their permeability coefficients _S21 were measured in the same manner as for sample 1, except that the distance _Dc between adjacent coil conductors in the stacking direction, the inner diameter _Rc of the coil, and the width Wc of the line portion were changed as shown in Table 1. The results are shown in Table 1, and in Figures 10, 11, 12, and 13.
FIG. 10 is a graph showing the transmission coefficient S21 of samples 1 to 5, FIG. 11 is a graph showing the transmission coefficient S21 of samples 6 to 10, FIG. 12 is a graph showing the transmission coefficient S21 of samples 11 to 15, and FIG. 13 is a graph showing the transmission coefficient S21 of samples 3 and 16.
For all samples, the ratio of the dimension of the arrangement area of the coil conductor in the stacking direction to the length dimension of the laminate was 93.3%, the same as for sample 1.
For Samples 11 to 16, the dimensions of the coil conductor arrangement area and the thickness of the coil conductor were not changed, but the number of layers of the coil conductor and the thickness of the ceramic green sheets were changed.
Moreover, samples 3, 8 and 12 all have the same distance between adjacent coil conductors in the lamination direction, the same inner diameter of the coil, and the same width of the line portion.

From the results in Table 1, it was found that the multilayer coil component of the present invention has a transmission coefficient S21 of -1.2 dB or more at 50 GHz and is excellent in high frequency characteristics.
Furthermore, it was found that the transmission coefficient _S21 at 50 GHz can be made -1.0 dB or more by setting the width _Wc of the line portion to 30 μm or more and 40 μm or less, the inner diameter Rc of the _coil to 50 μm or more and 80 μm or less, or the distance Dc between adjacent coil conductors in the stacking direction to 5 μm or more and 7 μm or less.
Furthermore, from the results of sample 16, it was found that the transmission coefficient S21 at 50 GHz can be further reduced by setting the line portion width _Wc to 30 μm or more and 40 μm or less, the coil inner diameter _Rc to 50 μm or more and 80 μm or less, and the distance _Dc between adjacent coil conductors in the stacking direction to 5 μm or more and 7 μm or less.

1 Multilayer coil component 10 Laminate 11 First end face 12 Second end face 13 First main surface 14 Second main surface 15 First side surface 16 Second side surface 21 First external electrode 22 Second external electrode 30 Coil 31, 31a, 31b, 31c, 31d, 35a, 35a1, _35a2 , _35a3 , _35a4 , _35b , _35b1 , 35b2, _35b3 , _35b4 Insulating layer 32, 32a, 32b, 32c, _32d , 132 Coil conductor 33a, 33b, 33c, 33d, 33p, 33q Via conductor 36a, 36b, 36c, 36d Line portion 37a, 37b, 37c, 37d Land portion 41 First connecting conductor 42 Second connecting conductor 60 Measuring jig 61 Signal path 62 Ground conductor 63 Network analyzer A Central axis D of coil _c Distance E between adjacent coil conductors in stacking direction ₁ Length E of first external electrode in portion covering first main surface ₂ Height L of first external electrode in portion covering first end face ₁ Length dimension L of laminate ₂ Length dimension L of laminated coil component ₃ Dimension R of arrangement area of coil conductor in stacking direction _C Inner diameter T of coil ₁ Height dimension T of laminate ₂ Height dimension W of laminated coil component ₁ Width dimension W of laminate ₂ Width dimension W of laminated coil component _C Width of line portion

Claims (10)

a laminate having a plurality of insulating layers laminated in a longitudinal direction and a coil built therein;
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 in the longitudinal direction together with the insulating layers,
The laminate has a first end face and a second end face opposing each other in the longitudinal direction, a first main surface and a second main surface opposing each other in a height direction perpendicular to the longitudinal direction, and a first side surface and a second side surface opposing each other in a width direction perpendicular to the longitudinal direction and the height direction,
the first external electrode covers at least a portion of the first end surface;
the second external electrode covers at least a portion of the second end surface,
a stacking direction of the laminate and a coil axis direction of the coil are parallel to the first main surface,
The distance between the coil conductors adjacent to each other in the stacking direction is 4 μm or more and 8 μm or less,
the coil conductor has a line portion and a land portion disposed at an end of the line portion,
the land portions of the coil conductors adjacent to each other in the stacking direction are connected to each other through via conductors,
The width of the line portion is 30 μm or more,
The inner diameter of the coil conductor is 50 μm or more and 100 μm or less,
A laminated coil component having a transmission coefficient S21 of -1.2 dB or more at 50 GHz. 2. The multilayer coil component according to claim 1 , wherein the transmission coefficient S21 at 50 GHz is −1.0 dB or more. 3. The multilayer coil component according to claim 1 , wherein the line portion has a width of 30 μm or more and 40 μm or less. 4. The laminated coil component according to claim 1 , wherein the inner diameter of the coil conductor is 50 μm or more and 80 μm or less. 5. The multilayer coil component according to claim 1, wherein the distance between the coil conductors adjacent to each other in the stacking direction is not less than 5 μm and not more than 7 μm. 6. The multilayer coil component according to claim 1, wherein the number of laminations of the coil conductor is 40 or more and 60 or less. 7. The multilayer coil component according to claim 1, wherein a length dimension of the laminate is 560 μm or more and 600 μm or less. 8. The laminated coil component according to claim 1 , wherein a dimension of an area in the laminate direction where the coil conductor is disposed is 85% or more and 95% or less of a length dimension of the laminate. 9. The laminated coil component according to claim 1 , wherein a dimension of an area in the laminate direction where the coil conductor is disposed is 90% or more and 95% or less of a length dimension of the laminate. the first main surface is a mounting surface,
the first external electrode extends to cover a portion of the first end face and a portion of the first main surface;
10. The multilayer coil component according to claim 1, wherein the second external electrode extends to cover a portion of the second end face and a portion of the first main surface.

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