JP2021097188A - Spiral inductor and passive integrated circuit - Google Patents

Abstract

To provide a spiral inductor that can achieve an improvement in a Q value and a passive integrated circuit using the spiral inductor.SOLUTION: A spiral wiring 2 is arranged on a substrate 1 to form a spiral inductor. A split wiring portion 2c is provided in a part of the spiral wiring 2. The split wiring portion 2c is arranged inside the spiral wiring 2. In the split wiring portion 2c, a wiring 2c1 and a wiring 2c2 divided into a plurality of parts are connected in parallel in a plan view. The split wiring portion 2c has an intersection portion 2x in the middle of wiring. At the intersection portion 2x, the inner and outer wirings are arranged in an intersecting manner via an insulating layer such that a wiring on the inner peripheral side becomes a wiring on the outer peripheral side and a wiring on the outer peripheral side becomes a wiring on the inner peripheral side. An electrically passive integrated circuit is configured to include at least one spiral inductor 9 and a capacitor 10.SELECTED DRAWING: Figure 1a

Description

The present invention relates to a high frequency spiral inductor in which a spiral wiring is provided on a substrate, and a passive integrated circuit using the spiral inductor.

As the filter in the high frequency band, an elastic wave filter such as a SAW filter or a BAW filter and a passive filter composed of an inductor and a capacitor are used. However, for a wide band filter in a high frequency band of around 5 GHz, a passive filter is mainly used instead of the elastic wave filter. The reason is that the SAW filter has a high Q value and is excellent in the steepness of the blocking region characteristic, but it is essentially difficult to widen the area.

As the physical shape of the passive filter, there is a structure in which components are laminated by using a thick film technology such as LTCC (Co-fired Laminated Ceramic Substrate). As another structure, a component is formed on a wafer plane by using a technique similar to that of a semiconductor process. The latter is often referred to as an IPD (Integrated Passive Device).

In this IPD, high Q values of the inductor and the capacitor, which are the components, are indispensable for reducing the loss and improving the blocking region characteristics. Normally, the Q value of the capacitor is several times or more higher than the Q value of the inductor, so it is important to increase the Q value of the inductor in order to reduce the loss and improve the blocking region characteristics.

The metal film used in IPD is thinner than the one formed by LTCC and has a smaller number of layers. Therefore, a structure called a spiral inductor is usually used.

7a to 7c are spiral inductors that have been widely used in the past, and are configured by forming a spiral wiring 51 on a substrate 50 (see, for example, Patent Document 1). In the spiral inductor of this example, when the wiring has two layers, as shown in FIGS. 7b and 7c, the spiral wiring 51 having a double structure is provided on the substrate 50 via the first insulating layer 52. It is formed. The spiral wiring 51 of this example shows a three-turn wiring including an outermost wiring portion 51a, an innermost wiring portion 51c, and an intermediate wiring portion 51b. The wiring portions 51a to 51c are electrically insulated and held by the second insulating layer 53. The inner end of the spiral wiring 51 is connected to a lead wire 54 for connecting to another circuit by a connecting portion 55. The outer end of the spiral wire 51 is connected to a lead wire 56 for connecting to another circuit.

In such a spiral inductor, the skin effect and the proximity effect in the high frequency band become problems. Here, the skin effect is a phenomenon in which the current concentrates only on the surface of the wiring. The proximity effect will be described with reference to FIG. When the currents Ia and Ib flow through the wiring portions 51a and 51b outside the innermost wiring portion 51c, respectively, the generated magnetic flux Φ acts on the inner wiring portion 51c. Due to this magnetic flux Φ, an eddy current Ix is generated in the inner wiring portion 51c. The eddy current Ix is in the same direction as the current Ic originally flowing in the wiring portion 51c on the inner side 51c1 of the wiring portion 51c, but is in the opposite direction on the outer side 51c2 of the wiring portion 51c. Therefore, as shown by hatching, the current Ic flows intensively in the inner wiring portion 51c. As a result, in the wiring portion 51c, the cross-sectional area through which the current flows becomes substantially narrow, and the series resistance becomes high. As described above, in the spiral inductor, not only the skin effect but also the proximity effect causes a problem that the series resistance of the wiring is increased. This increase in series resistance becomes an obstacle when improving the Q value.

In order to solve such a problem, conventionally, as shown in FIG. 9, the width t1 of the innermost wiring portion 51c is narrower than the width t2 of the other wiring portions 51b and the width t3 of the wiring portion 51a (t1). Those with <t2 <t3) are known. In this case, a structure in which the wiring interval becomes wider (W1 <W2) toward the center of the spiral wiring 51 may be adopted.

As another conventional example in which the skin effect and the proximity effect are further suppressed, there are the structures shown in FIGS. 10a to 10c. The structures shown in FIGS. 10a to 10c are simplified structures disclosed in Patent Document 2. This is a division of the spiral wiring 57 formed on the substrate 50 in a plan view (that is, when viewed in the direction perpendicular to the formation surface of the spiral wiring 57) over the entire circumference. These illustrated examples show a three-turn spiral wiring. That is, the spiral wiring 57 includes the wiring 57a1 and the wiring 57a2 of the outermost divided wiring portion 57a, the wiring 57b1 and the wiring 57b2 of the innermost divided wiring portion 57b, and the wiring 57c1 and the wiring 57c2 of the innermost divided wiring portion 57c. And have. The wiring 57a1 and the wiring 57a2 of the outermost divided wiring portion 57a are electrically insulated from each other at the intersection 57x1 and intersect with each other. Similarly, the wiring 57b1 and the wiring 57b2 of the divided wiring portion 57b inside thereof are electrically insulated from each other at the intersection 57x2 and intersect with each other. Further, the wiring 57c1 and the wiring 57c2 of the innermost divided wiring portion 57c are also electrically insulated from each other at the intersection 57x3 and intersect with each other. The inner ends of the wirings 57c1 and 57c2 of the innermost divided wiring portion 57c are connected to the lead wire 58. Further, the outer ends of the wiring 57a1 and the wiring 57a2 of the outermost divided wiring portion 57a are connected to a lead wire 59 for connecting to another circuit.

Japanese Unexamined Patent Publication No. 2010-16240 China Utility Model No. 204391102

If the spiral wiring structure as shown in FIG. 9 is adopted, the narrow wiring portion 51c can be effectively used as a conductor current path, which can contribute to the improvement of the Q value. However, narrowing the innermost wiring portion 51c is not sufficient to suppress the proximity effect, and there is a limit to the improvement of the Q value.

On the other hand, as shown in FIGS. 10a to 10c, when the spiral wiring 57 is divided in a plan view, the eddy current generated inside the spiral wiring 57 is reduced and the Q value is improved as compared with the inductor of FIG. realizable. However, it is necessary to secure a certain width or more between the divided wiring portion 57a, the divided wiring portion 57b, and the divided wiring portion 57c, respectively. Further, it is necessary to secure a certain width or more between the wiring 57a1 and the wiring 57a2 of each divided wiring portion, between the wiring 57b1 and the wiring 57b2, and between the wiring 57c1 and the wiring 57c2. Therefore, when trying to secure this width, the overall size of the inductor becomes large, and the line width in the outer divided wiring portion 57a becomes thin, so that the series resistance also increases, and there is a limit to the improvement of the Q value.

In view of the above problems, an object of the present invention is to provide a spiral inductor capable of achieving an improvement in Q value and a passive integrated circuit using the spiral inductor.

One aspect of the spiral inductor of the present invention is a spiral inductor in which spiral wiring is arranged on a substrate, the spiral wiring portion has a divided wiring portion, and the divided wiring portion is wired in a plan view. Has a structure in which is divided into a plurality of parts and the divided wirings are connected in parallel, the divided wiring portion is arranged inside the spiral wiring, and the divided wiring portion is in the middle of wiring. The inner and outer wirings are arranged in a crossing manner via an insulating layer so that the inner peripheral side wiring included in the divided wiring portion becomes the outer peripheral side wiring and the outer peripheral side wiring becomes the inner peripheral side wiring. Is.

By providing the divided wiring portion inside the spiral wiring in this way, it is possible to reduce the eddy current concentrated inside the spiral wiring by the proximity effect and suppress the increase in series resistance due to the proximity effect. Further, since the outer wiring portion has a non-divided wiring structure, the series resistance in the outer wiring portion does not increase. Moreover, the split wiring section can make the series resistance of each wiring included in the split wiring section substantially equal by crossing the inner and outer wirings at the intersection. Therefore, the series resistance of the entire winding can be reduced. As a result, a higher Q value than that of the conventional spiral inductor can be obtained.

In another aspect of the spiral inductor of the present invention, in the above-described aspect, the divided wiring portion is arranged only in the innermost portion of the spiral wiring.

In this way, by arranging the divided wiring portion only in the innermost portion of the spiral wiring, the proximity effect can be effectively suppressed. Further, since the outer wiring portion is not provided with the divided wiring portion, the entire spiral wiring portion can be downsized as compared with the case where the outer wiring portion is also divided on a plane. Therefore, according to the structure of the spiral wiring of the present invention, the area efficiency can be improved in the sense that the wiring can be efficiently arranged in a limited area, so that the Q is higher than that of the conventional spiral inductor. You can get the value.

In another aspect of the spiral inductor of the present invention, in the above-described aspect, the spiral wiring has a plurality of divided wiring portions having different numbers of divisions in a plan view, and the inner divided wiring portion of the plurality of divided wiring portions. The number of divisions is larger for each part.

The magnetic flux density is high inside the spiral wiring, and the proximity effect is strong. Therefore, by providing a plurality of divided wiring portions and increasing the number of divisions on the plane toward the inner divided wiring portions, the proximity effect is suppressed. According to this aspect, the proximity effect can be suppressed according to the position of the wiring. Therefore, it is possible to significantly reduce the series resistance in the inner wiring, which is important for suppressing the proximity effect. Further, by reducing the number of divisions of the divided wiring as the degree of influence of the proximity effect becomes smaller, it is possible to form a pattern having good area efficiency. Therefore, the increase in series resistance due to the expansion of space is also suppressed. As a result, a higher Q value can be obtained as compared with the conventional spiral inductor.

In another aspect of the spiral inductor of the present invention, in the above-described aspect, the outermost wiring portion of the spiral wiring has a plurality of wirings laminated via an insulating layer, and the plurality of laminated wirings. The wiring is connected in series with each other.

In this way, in the outermost wiring portion, by connecting a plurality of electrically insulated wires in series in the stacking direction, a high inductance can be obtained in a narrower space and a shorter metal length, and the Q value can be obtained. Is improved.

One aspect of the passive integrated circuit of the present invention includes one or more of the spiral inductors described above, and also includes a metal, an insulator, and a capacitor having a metal structure.

As described above, by including the spiral inductor having a high Q value of the present invention in the passive integrated circuit, a circuit having a low insertion loss can be realized. If the passive integrated circuit is, for example, a filter, low insertion loss and steep blocking zone characteristics can be realized.

The spiral inductor of the present invention can suppress the skin effect and the proximity effect, improve the area efficiency, and reduce the series resistance. Moreover, the divided wiring portion can make the series resistance of each wiring included in the divided wiring portion substantially equal by crossing the inner and outer wirings with the insulating layer. Therefore, the Q value can be improved. Further, the passive integrated circuit using the spiral inductor of the present invention can realize a circuit with reduced insertion loss.

It is a top view which shows the 1st Embodiment of the spiral inductor according to this invention. FIG. 1A is a sectional view taken along the line AA of FIG. 1a. It is a cross-sectional view of BB of FIG. 1a. FIG. 3 is a cross-sectional view taken along the line CC of FIG. 1a. It is a figure which shows the length of the internal / external wiring in the divided wiring part of FIG. 1a. It is sectional drawing which shows the example of another wiring structure in the spiral inductor of FIG. 1a. It is sectional drawing which shows the structure of the intersection of the divided wirings when the wiring structure of FIG. 1f is adopted. It is a top view which shows the 2nd Embodiment of the spiral inductor according to this invention. FIG. 2 is a cross-sectional view taken along the line DD of FIG. 2a. FIG. 2 is a cross-sectional view taken along the line EE of FIG. 2a. FIG. 2 is a cross-sectional view taken along the line FF of FIG. 2a. It is a figure which shows the length of the internal / external wiring in the divided wiring part of FIG. 2a. It is sectional drawing which shows the example of another wiring structure in the spiral inductor of FIG. 2a. It is sectional drawing which shows the structure of the intersection of the divided wirings when the wiring structure of FIG. 2f is adopted. It is a top view which shows the 3rd Embodiment of the spiral inductor according to this invention. FIG. 3 is a cross-sectional view taken along the line GG of FIG. 3a. FIG. 3 is a sectional view taken along the line HH of FIG. 3a. FIG. 3 is a cross-sectional view taken along the line II of FIG. 3a. It is sectional drawing which shows the other wiring structure example in the spiral inductor of FIG. 3a. It is sectional drawing which shows the structure of the intersection of the divided wirings when the wiring structure of FIG. 3e is adopted. It is a figure which shows the winding pattern of an Example, a comparative example, and two conventional examples of this invention. It is a graph which shows the change of the Q value with respect to the frequency of the inductor which has each winding pattern of FIG. It is a top view which shows one Embodiment of the passive integrated circuit configured by using the spiral inductor of this invention. It is a top view which shows an example of the conventional spiral inductor. FIG. 7 is a cross-sectional view taken along the line JJ of FIG. 7a. FIG. 7 is a cross-sectional view taken along the line KK of FIG. 7a. It is explanatory drawing of the proximity effect in a spiral inductor. It is a top view which shows another example of the conventional spiral inductor. It is a top view which further shows another example of the conventional spiral inductor. 10a is a cross-sectional view taken along the line LL of FIG. 10a. FIG. 10A is a cross-sectional view taken along the line MM of FIG. 10a.

The spiral inductor according to the present invention will be described according to the embodiment. 1a-1g show a first embodiment of a spiral inductor according to the present invention. The spiral inductor of this embodiment is configured by forming the spiral wiring 2 on the substrate 1. It is preferable to use a material having a resistance value of 1 kΩ · cm or more for the substrate 1. As a specific example of the substrate 1, high-resistance silicon, gallium arsenide, sapphire, polycrystalline alumina, glass, or the like can be used. However, the substrate 1 used in the present invention is not limited to those made of these materials.

In this embodiment, the spiral wiring 2 is formed on the substrate 1 via the first insulating layer 3. For example, silicon oxide is used for the first insulating layer 3. The first insulating layer 3 is used for the purpose of reducing the capacitance between the spiral wirings 2 when a material having a high relative permittivity is used as the substrate 1. Therefore, depending on the material of the substrate 1, the first insulating layer 3 is not always required. The spiral wiring 2 is formed by being insulated and held by a second insulating layer 4 on the first insulating layer 3. For the second insulating layer 4, for example, a polyimide resin is used, but another insulating material may be used.

Generally, the spiral wiring 2 may be provided with gold, copper, or the like in a layered manner, but may be formed into a different shape by using another metal. In this embodiment, the spiral wiring 2 has a number of turns of 3 times. That is, the spiral wiring 2 includes an outermost wiring portion 2a, an intermediate wiring portion 2b, and an innermost divided wiring portion 2c. The number of turns of the spiral wiring 2 may be two turns or four or more turns. Further, in this example, the winding pattern of the spiral wiring 2 is formed in a quadrangular shape, but other polygonal or circular shapes may be used.

The innermost divided wiring portion 2c is a part of the spiral wiring 2, and the wiring is divided into a plurality of parts in a plan view. The divided wiring portion 2c of this example shows an example in which the divided wiring portion 2c is divided into two wirings including the first wiring 2c1 and the second wiring 2c2. Further, in this example, the line widths of the first wiring 2c1 and the second wiring 2c2 constituting the divided wiring portion 2c are the line widths of the wiring portion 2a outside the divided wiring portion 2c and the wiring portion 2b in the intermediate portion. It is formed narrower. The number of divisions of the divided wiring portion 2c may be 3 divisions or 4 divisions. The other wiring portion 2a and the wiring portion 2b have a non-divided structure. Further, the distance between the wiring portion 2a and the wiring portion 2b, between the wiring portion 2b and the divided wiring portion 2c, and between the first wiring 2c1 and the second wiring 2c2 in the divided wiring portion 2c becomes an optimum value. It can be appropriately selected as described above, and is not limited to the illustrated example.

As shown in FIG. 1b, the wiring portion 2a, the wiring portion 2b, and the divided wiring portion 2c each have a double structure including a laminated lower wiring 20 and an upper wiring 21. However, as shown in FIG. 1c, the inner end portion of the spiral wiring 2 is connected to the lead wire 6 at the connecting portion 5. At the intersection of the wiring portion 2a and the wiring portion 2b with the lead wire 6, only the upper wiring 21 is provided because the second insulating layer 4 is interposed.

As shown in FIG. 1a, the first wiring 2c1 and the second wiring 2c2 included in the divided wiring portion 2c are arranged at positions where the inner and outer positions are reversed with the intersection 2cx as a boundary. That is, in the divided wiring portion 2c, the part 2c11 of the first wiring 2c1 is located outside the part 2c21 of the second wiring 2c2 on the connection portion 5a side with the lead wire 6 rather than the intersection portion 2cx. To do. On the other hand, of the divided wiring portions 2c, the remaining portion 2c12 of the first wiring 2c1 is located inside the remaining portion 2c22 of the second wiring 2c2 on the connecting portion 5b side with the wiring portion 2b with respect to the intersecting portion 2cx.

FIG. 1d shows the cross-sectional structure of the intersection 2cx. In this example, the lower wiring 20x of the inner wiring 2c21 of the second wiring 2c2 is extended to the outer peripheral side, and the upper wiring 21 of the outer wiring 2c22 of the second wiring 2c2 is connected to the extension portion. Further, the inner wiring 2c12 of the first wiring 2c1 is formed on the surface of the insulating layer 4. As a result, the first wiring 2c1 and the second wiring 2c2 at the intersection 2cx are electrically insulated. The structure of the wiring intersection 2cx is not limited to this structure. At the intersection, various changes can be made, for example, the first wiring 2c1 is arranged on the lower side and the second wiring 2c2 is arranged on the upper side.

In this example, the spiral wiring 2 is formed in a quadrangular shape. That is, the divided wiring portion 2c has three corner portions 26, 27, and 28 that bend at right angles between the connecting portion 5a with the lead wire 6 and the connecting portion 5b with the wiring portion 2b. The intersection 2cx is provided at the middle corner 27 of the three corners 26, 27, 28. Therefore, when the length of the first wiring 2c1 between the connecting portion 5a and the connecting portion 5b is L1 and the length of the second wiring 2c2 is L2, the lengths of both are substantially the same for the following reasons. Equal (L1≈L2).

That is, in FIG. 1e, assuming that the length of each side of the first wiring 2c1 is a1 to a4 and the length of each side of the second wiring 2c2 is b1 to b4.
L1 = a1 + a2 + a3 + a4 ... (1)
L2 = b1 + b2 + b3 + b4 ... (2)
Will be. The length of each side of each wiring is set to the length of the center line portion of the line width of the wiring. Here, since the distance between the first wiring 2c1 and the second wiring 2c2 is almost equal over the entire circumference of the divided wiring portion 2c.
a2 ≒ b2 ... (3)
a3 ≒ b3 ... (4)
b1-a1 ≒ a4-b4 ... (5)
And for this reason
L1 ≒ L2 ... (6)
Will be. As described above, since the length L1 of the first wiring 2c1 is substantially equal to the length of the second wiring 2c2, the series resistance proportional to the length of the wiring is substantially equal.

As shown in this embodiment, by providing the divided wiring portion 2c divided in parallel inside the spiral wiring 2, the eddy current concentrated inside the inner wiring is reduced by the proximity effect, and the proximity effect is applied. It is possible to suppress an increase in series resistance. That is, the eddy current generated in these wirings is reduced by dividing the inner wiring portion, which tends to cause a proximity effect because the magnetic flux density tends to be high in the spiral wiring, into a plurality of inner wirings 2c1 and outer wirings 2c2. be able to.

Moreover, since the divided wiring portion 2c intersects the first wiring 2c1 and the second wiring 2c2 at the intersection 2cx, the lengths of the first wiring 2c1 and the second wiring 2c2 are made substantially equal. , These series resistances can be made almost equal. Therefore, the series resistance of the divided wiring portion 2c can be reduced without the current flowing through the first wiring 2c1 and the second wiring 2c2 being biased to either one.

Further, since the outer wiring portion 2a and the wiring portion 2b are not divided, it is possible to secure a sufficient wiring width within a limited space and reduce the series resistance. Therefore, the area efficiency of the outer wiring portion 2a and the wiring portion 2b is improved as compared with the case where the wiring portion 2b is divided on a plane, and the entire wiring portion can be miniaturized. As a result, the series resistance is lowered in combination with the arrangement of the divided wiring portion 2c inside, and a spiral inductor having a higher Q value than the conventional one can be obtained.

FIG. 1f is a modified example of the wiring structure shown in FIG. 1b. In this wiring structure, the second insulating layer 4 is provided at most locations between the wiring portion 2a, the wiring portion 2b, and the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2c. However, in the connecting portion 5a in which the inner end portion of the spiral wiring 2 is connected to the lead wire 6, the lower wiring 20 and the upper wiring 21 of the split wiring portion 2c are connected. Further, in the wiring portion 2a and the wiring portion 2b, the lower wiring 20 and the upper wiring 21 are connected in the vicinity of the portion intersecting the lead wire 6. Further, the lower wiring 20 and the upper wiring 21 of the wiring portion 2a are also connected to the lead wire 7 at the other end of the spiral wiring 2.

FIG. 1g shows the structure of the intersection 2cx when the wiring structure shown in FIG. 1f, that is, the structure in which the upper and lower wirings are separated via an insulating layer is adopted. In the structure of the intersection 2cx, the upper wiring 21 and the lower wiring 20x in the inner wiring 2c21 of the second wiring 2c2 are connected by the vertical wiring 20y.

As shown in FIG. 1f, if the spiral wiring 2 has a structure in which the lower wiring 20 and the upper wiring 21 are separated via the insulating layer 4, the current flowing through the spiral wiring 2 is divided into the lower wiring 20 and the upper wiring 21. Can be split. Therefore, the skin effect is alleviated by increasing the current path, the substantial current flow path cross-sectional area can be increased, and the series resistance can be reduced. Therefore, the Q value can be further improved.

2a-2g show a second embodiment of the spiral inductor according to the present invention. In this embodiment, as the spiral wiring 2A, the outermost wiring portion 2d, the split wiring portion 2e in the intermediate portion, and the innermost split wiring portion 2f are provided. The divided wiring portion 2e in the intermediate portion is composed of two wirings, a first wiring 2e1 and a second wiring 2e2, which are connected in parallel to each other. The innermost divided wiring portion 2f is composed of first to fourth wirings 2f1 to 2f4 connected in parallel to each other.

As shown in FIG. 2b, the wiring unit 2d, the divided wiring unit 2e, and the divided wiring unit 2f are composed of the laminated lower wiring 20 and the upper wiring 21 as in the first embodiment. Further, as shown in FIG. 2c, the connection structure between the lead wire 6 and the connecting portion 5c is the same as that of the first embodiment. Further, the structure of the intersection between the leader wire 6 and the wiring portion 2d and the divided wiring portion 2e and the structure of the intersection between the leader wire 6 and the wiring portion 2a and the wiring portion 2b in the first embodiment are also insulated. The structure is such that the layer 4 is interposed.

In this example, the line widths of the first wiring 2e1 and the second wiring 2e2 constituting the divided wiring portion 2e are formed to be narrower than the line width of the outer wiring portion 2d. The line widths of the first to fourth wirings 4f1 to 4f4 of the innermost divided wiring portion 2f are formed to be narrower than the line widths of the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e. That is, the wire width of the spiral wiring 2A is narrower as the wiring of the inner wiring portion.

Each end of each of the four wires 2f1 to 2f4 included in the divided wiring portion 2f is all connected to the connecting portion 5c with the lead wire 6. Of these four wirings 2f1 to 2f4, the other ends of the first wiring 2f1 and the second wiring 2f2, which are the inner wirings, are connected to the second wiring 2e2 constituting the divided wiring portion 2e, and the connection portion 5d. Connected at. On the other hand, of these four wirings 2f1 to 2f4, the other ends of the third wiring 2f3 and the fourth wiring 2f4, which are the outer wirings, are connected to the first wiring 2e1 constituting the divided wiring portion 2e. It is connected in the part 5e.

The first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e in the intermediate portion are arranged at positions where the inner and outer positions are reversed with the intersection 2ex as a boundary. That is, between the intersection 2ex and the connection portions 5d and 5e that connect the split wiring portion 2f, a part 2e11 of the first wiring 2e1 of the split wiring portion 2e is one of the second wirings 2e2. It is located outside the portion 2e21. On the other hand, in the divided wiring portion 2e, between the intersection portion 2ex and the connection portion 5f that connects to the wiring portion 2d, the remaining portion 2e12 of the first wiring 2e1 is the remaining portion 2e22 of the second wiring 2e2. Located inside.

Of the innermost divided wiring portions 2f, the first wiring 2f1 and the second wiring 2f2 are arranged at positions where the inner and outer positions are reversed with the intersection 2fx1 as a boundary. That is, between the intersection 2fx1 and the connecting portion 5c with the lead wire 6, the part 2f11 of the first wiring 2f1 is located outside the part 2f21 of the second wiring 2f2. On the other hand, between the intersection 2fx1 and the connection portion 5d of the split wiring portion 2e with the second wiring 2e2, the remaining portion 2f12 of the first wiring 2f1 is located inside the remaining portion 2f22 of the second wiring 2f2. To do.

Of the innermost divided wiring portions 2f, the third wiring 2f3 and the fourth wiring 2f4 are arranged at positions where the inner and outer positions are reversed with the intersection 2fx2 as a boundary. That is, between the intersection 2fx2 and the connection portion 5c with the lead wire 6, the part 2f31 of the third wiring 2f3 is located outside the part 2f41 of the fourth wiring 2f4. On the other hand, between the intersection 2fx2 and the connection portion 5e of the split wiring portion 2e with the first wiring 2e1, the remaining portion 2f32 of the third wiring 2f3 is located inside the remaining portion 2f42 of the fourth wiring 2f4. To do.

FIG. 2d shows the cross-sectional structure of the intersection 2fx1 between the first wiring 2f1 and the second wiring 2f2. As shown in this figure, the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 is extended to the outer peripheral side, and the upper wiring 21 of the outer wiring 2f22 of the second wiring 2f2 is connected to the extension portion. Further, the inner wiring 2f12 of the first wiring 2f1 is formed on the surface of the insulating layer 4. As a result, the first wiring 2f1 and the second wiring 2f2 are electrically insulated. The intersection 2fx2 and the intersection 2ex are also realized by the same cross-sectional structure, but the illustration is omitted.

In the wiring structure having the intersection 2fx1 as shown in FIG. 2a, the series resistance between the first wiring 2f1 and the second wiring 2f2 in the divided wiring portion 2f is due to the existence of the intersection 2fx1 for the reason explained in FIG. Almost equal. Similarly, the series resistance of the third wiring 2f3 and the fourth wiring 2f4 in the divided wiring portion 2f is also substantially equal due to the presence of the intersection portion 2fx2 for the reason described with reference to FIG.

Here, the average length of the inner first wiring 2f1 and the second wiring 2f2 in the divided wiring portion 2f is L (f12), and the outer third wiring 2f3 and the fourth wiring 2f4 are combined. Let the average length be L (f34). Since the third wiring 2f3 and the fourth wiring 2f4 are outside the first wiring 2f1 and the second wiring 2f2,
L (f12) <L4 (f34) ... (7)
Will be. As described above, since there is a difference between the length L (f12) and the length L4 (f34), a difference in series resistance occurs between the inner wirings 2f1 and 2f2 and the outer wirings 2f3 and 2f4. However, this difference in series resistance is the difference in length between the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e connected to the inner wiring 2f1, 2f2 and the outer wiring 2f3, 2f4, respectively. Can be made smaller or eliminated by adjusting. Next, the adjustment of the difference in the length of the wiring will be described.

FIG. 2e is a diagram for explaining the wiring lengths of the divided wiring unit 2e and the divided wiring unit 2f. In FIG. 2e, the lengths c1 to c4 of each side of the first wiring 2f1 and the second wiring 2f2 inside the divided wiring portion 2f are between the first wiring 2f1 and the second wiring 2f2. It is set to the length of the center line of the groove. Similarly, the lengths d1 to d4 of each side of the third wiring 2f3 and the fourth wiring 2f4 outside the divided wiring portion 2f are the grooves between the third wiring 2f3 and the fourth wiring 2f4. It is set to the length of the center line of. Here, the length of the first wiring 2f1 and the second wiring 2f2 inside the divided wiring portion 2f is defined as L (f12). Further, the length of the outer third wiring 2f3 and the fourth wiring 2f4 together is defined as L4 (f34).
These lengths L (f12) and L4 (f34) are expressed by the following equations, respectively.
L (f12) = c1 + c2 + c3 + c4 ... (8)
L (f34) = d1 + d2 + d3 + d4 ... (9)

On the other hand, regarding the length L (2e1) of the first wiring 2e1 and the length L (2e2) of the second wiring 2e2 of the divided wiring portion 2e, the lengths e1 to e4 of each side of each wiring 2e1 and the wiring 2e2 and The lengths f1 to f4 are set to the length of the center line portion of the line width of the wiring. The length L (2e1) of the first wiring 2e1 and the length L (2e2) of the second wiring 2e2 of the divided wiring portion 2e are expressed by the following equations.
L (2e1) = e1 + e2 + e3 + e4 ... (10)
L (2e2) = f1 + f2 + f3 + f4 ... (11)
And
L (f34) -L (f12) ≒ L (2e2) -L (2e1) ... (13)
The length of the wiring and the distance between the grooves are set so as to be. That is, the difference between the average length of the third wiring 2f3 and the fourth wiring 2f4 of the divided wiring portion 2f and the average length of the first wiring 2f1 and the second wiring 2f2 is determined by the first of the divided wiring portions 2e. It is absorbed by the difference in length between the wiring 2e1 and the second wiring 2e2.

As in the second embodiment, a plurality of divided wiring portions having different numbers of divided wirings are provided, and the inner divided wiring portions increase the number of divided wirings on the plane to suppress the proximity effect. The proximity effect can be suitably suppressed according to the position of the portion. Therefore, it is possible to substantially reduce the series resistance in the inner divided wiring portion 2e and the divided wiring portion 2f, which are important for suppressing the proximity effect. Further, by reducing the number of divisions of the divided wiring portion 2e and the divided wiring portion 2f as the degree of influence of the proximity effect becomes smaller, an area-efficient pattern can be formed. Therefore, the increase in series resistance due to the expansion of space is also mitigated.

Moreover, the divided wiring portion 2e and the divided wiring portion 2f intersect at the intersection portion 2ex and the intersection portions 2fx1 and 2fx2. Therefore, the lengths of the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e are made substantially equal, and the lengths of the first wiring 2f1 and the second wiring 2f2 of the divided wiring portion 2f are substantially equal. Then, the lengths of the third wiring 2f3 and the fourth wiring 2f4 can be made substantially equal. Therefore, these series resistances can be made substantially equal.

Further, the difference between the average length of the third wiring 2f3 and the fourth wiring 2f4 of the divided wiring unit 2f and the average length of the first wiring 2f1 and the second wiring 2f2 of the divided wiring unit 2f is determined by the divided wiring unit. It is absorbed by the difference in length between the first wiring 2e1 and the second wiring 2e2 of 2e. Therefore, it is possible to eliminate or reduce the difference in series resistance due to the difference in the length of the internal and external wiring due to the number of divisions of the divided wiring portion 2f being 4.

For this reason, a higher Q value can be obtained as compared with the conventional spiral inductor.

FIG. 2f is a modification of the wiring portion structure shown in FIG. 2b, in which the wiring portion 2d, the split wiring portion 2e, and the split wiring portion 2f are located in most of the locations between the lower wiring 20 and the upper wiring 21. The insulating layer 4 is provided. However, as shown in FIG. 2c, at least the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2f are connected at the connecting portion 5c in which the inner end portion of the spiral wiring is connected to the lead wire 6. Further, in the wiring portion 2d and the split wiring portion 2e, the lower wiring 20 and the upper wiring 21 are connected in the vicinity of the portion intersecting the lead wire 6. Further, the lower wiring 20 and the upper wiring 21 of the wiring portion 2d are also connected to the lead wire 7 at the other end of the spiral wiring.

As shown in FIG. 2f, if the spiral wiring has a structure in which the lower wiring 20 and the upper wiring 21 are separated via the insulating layer 4, the current flowing through the spiral wiring is divided into the lower wiring 20 and the upper wiring 21. be able to. Therefore, the skin effect is alleviated, the substantial current flow path cross-sectional area can be increased, and the series resistance can be reduced. Therefore, the Q value can be further improved.

FIG. 2g shows the cross-sectional structure of the intersection 2fx1 between the first wiring 2f1 and the second wiring 2f2 in the divided wiring portion 2f in the wiring structure shown in FIG. 2f. As shown in this figure, the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 is extended to the outer peripheral side, and the upper wiring 21 of the outer wiring 2f22 of the second wiring 2f2 is connected to the extension portion. Further, the inner wiring 2f12 of the first wiring 2f1 is formed on the surface of the insulating layer 4. As a result, the first wiring 2f1 and the second wiring 2f2 at the intersection 2fx1 are electrically insulated. The upper wiring 21 and the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 are connected by the vertical wiring 20y. The intersection 2fx2 and the intersection 2ex can also be realized with the same cross-sectional structure.

3a-3f show a third embodiment of the spiral inductor according to the present invention. In this embodiment, the outermost wiring portion 2g of the spiral wiring 2B has a plurality of wirings laminated via the insulating layer 4. In this example, an example in which this wiring is composed of two wires, a lower wiring 22 and an upper wiring 23, is shown. The end portion of the lower wiring 22 is connected in series with the terminal portion 23b of the upper wiring 23 of the upper wiring 23 at the connection portion 24. As shown in FIG. 3c, in the upper wiring 23 in the wiring portion 2g, the outermost terminal portion 23b and the inner wire portion 23a intersect with the lead wire 6 via the insulating layer 4. The wiring constituting the outermost wiring portion 2g may be not only the upper and lower two layers but also three or more layers as in this example.

As shown in FIGS. 3a and 3b, the wiring portion inside the spiral wiring 2B is configured as a split wiring portion 2h. That is, the inner divided wiring portion 2h is divided into an inner wiring 2h1 and an outer wiring 2h2. One end of the inner wiring 2h1 and the outer wiring 2h2 is connected by a connecting portion 5a with the lead wire 6. The other ends of the inner wiring 2h1 and the outer wiring 2h2 are connected to the upper wiring 23 of the wiring portion 2g by the connection portion 25. The number of divisions of the wiring in the divided wiring portion 2h may be three or more divisions instead of two divisions.

The current route of the spiral wiring 2B is as follows: lead wire 6-connection portion 5-divided wiring portion 2h (2h1 and 2h2) -connection portion 25-upper wiring of wiring portion 2g 23-connection portion 24-lower wiring portion 22 of wiring portion 2g. -The order is lead wire 7.

FIG. 3d shows the cross-sectional structure of the intersection 2hx. In this example, the lower wiring 20x of the second wiring 2h22 is extended to the outer peripheral side, and the upper wiring 21 of the second wiring 2h21 is connected to the extension portion. Further, the first wiring 2h11 is formed on the surface of the insulating layer 4. As a result, the first wiring 2h1 and the second wiring 2h21 at the intersection 2hx are electrically insulated.

As in this embodiment, the outer wiring portion 2g is composed of a plurality of wirings 22 and wirings 23, and by connecting these wirings in series, the same inductance can be obtained in a narrower space and a shorter wiring length. It can be done and the Q value is improved. Further, also in this embodiment, since the intersecting portion 2hx is provided in the divided wiring portion 2h, further improvement of the Q value can be achieved.

FIG. 3e is a modification of the wiring portion structure shown in FIG. 3b, in which the insulating layer 4 is provided between the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2h. However, as shown in FIG. 3c, at least in the connecting portion 5 in which the inner end portion of the spiral wiring 2B is connected to the lead wire 6, the lower wiring 20 and the upper wiring 21 of the split wiring portion 2h are connected.

FIG. 3f shows the cross-sectional structure of the intersection 2hx. In the structure of the intersection 2hx, the lower wiring 20x of the inner wiring 2h22 of the second wiring 2h2 and the upper wiring 21 of the outer wiring of the second wiring 2h2 are connected by the vertical wiring 20y.

As shown in FIG. 3e, if the divided wiring portion 2h has a structure in which the lower wiring 20 and the upper wiring 21 are separated via the insulating layer 4, the current flowing through the divided wiring portion 2h is transferred to the lower wiring 20 and the upper wiring 21. Can be split into and. Therefore, the skin effect is alleviated, the substantial current flow path cross-sectional area can be increased, and the series resistance can be reduced. Therefore, the Q value can be further improved.

FIG. 4 is a diagram showing winding patterns in the inductors of the examples, comparative examples, and two conventional examples of the present invention used for comparison in order to investigate the improvement of the Q value by the present invention. In FIG. 4, in the embodiment of A of the present invention, the innermost portion is a divided wiring portion 2c having inner and outer wiring, and the divided wiring portion 2c has an intersecting portion 2x. This A embodiment has the winding structure shown in the embodiment of FIG. 1a. The comparative example of B has the same divided wiring portion 2c as in the embodiment of A, but does not have the intersection portion 2x. The first conventional example of C corresponds to the winding structure shown in FIGS. 7a to 7c. The second conventional example of D corresponds to the winding structure shown in FIGS. 10a to 10c.

In FIG. 4, a gallium-arsenide substrate was used as the substrate in the examples, comparative examples, and two conventional examples of the present invention, and the winding was made of gold. The number of turns of the winding (however, one winding of the divided wiring portion is one turn) is 3, the width W1 of the entire winding portion is 200 μm, and the width W2 of the innermost winding portion is 100 μm. Further, the width ta1 of the wide wirings 2a, 2b, 51a to 51c was set to 25 μm. Further, the interval ta2 of the winding portion was set to 15 μm. Further, the width tb1 of the wiring in the divided wiring portions 2c and 57a to 57c was set to 10 μm, and the interval tb2 between the wirings was set to 5 μm. The thickness of all wiring was 10 μm.

FIG. 5 is a graph showing changes in the Q value with respect to the frequency of the inductor having each winding pattern of FIG. As shown in FIG. 5, in the case of 2.0 to 5.5 GHz, which is a frequency band generally used or planned to be used in mobile communication equipment, in the case of the example (A) of the present invention, a comparative example ( An excellent Q value was obtained as compared with B) and the conventional examples (C) and (D).

FIG. 6 is a plan view showing an embodiment of a passive integrated circuit configured by using the spiral inductor 9 according to the present invention. In FIG. 6, the winding of the spiral inductor has the structure of the present invention. That is, the inner wiring of the spiral inductor 9 is composed of the divided wiring portion 90 including the first wiring 90a and the second wiring 90b. The first wiring 90a and the second wiring 90b intersect at the intersection 90x via the insulating layer. The filter 12 as a passive integrated circuit of FIG. 6 includes a spiral inductor 9, a spiral inductor 9X, a capacitor 10 and a capacitor 10X. One end of the spiral inductor 9 is connected to a capacitor (MIM capacitor) 10 having a "metal / insulator / metal structure" (MIM structure) via a connection line 11a. The other end of the spiral inductor 9 is connected to another MIM capacitor 10X via a connection line 11b. One end of the spiral inductor 9X is connected to the capacitor 10 via a connection line 11c. The other end of the spiral inductor 9X is connected to the capacitor 10X via a connection line 11d.

As described above, the passive integrated circuit of the present invention includes one or more spiral inductors 9 of the present invention and a capacitor 10. As described above, by including the spiral inductor 9 having a high Q value of the present invention, a passive integrated circuit having a low insertion loss can be realized. As shown in the illustrated example, the filter 12 using the spiral inductor 9 of the present invention can realize a low insertion loss and a steep blocking region characteristic. As a passive integrated circuit, in addition to a filter, it can be effectively used for improving the characteristics of functions such as balun (balanced / unbalanced conversion), diplexer (signal separation between high frequency region and low frequency region), impedance matching, and the like.

Although the present invention has been described above, when the present invention is carried out, various modifications and additions can be made without deviating from the gist of the present invention, not limited to the above-mentioned examples.

1 Substrate 2, 2A, 2B Swirl wiring 2a, 2b, 2d, 2g Wiring part 2c, 2e, 2f, 2h Divided wiring part 2c1, 2c2, 2e1, 2e2, 2f1 to 2f4 Wiring 3 First insulating layer 4 Second Insulation layer 9, 9X spiral inductor 10, 10X capacitor 12 filter

Claims (5)

A spiral inductor in which spiral wiring is arranged on a board.
A split wiring portion is provided as a part of the spiral wiring.
The divided wiring portion has a structure in which wiring is divided into a plurality of parts in a plan view and the divided wirings are connected in parallel.
The divided wiring portion is arranged inside the spiral wiring, and is arranged inside the spiral wiring.
In the divided wiring portion, the inner and outer wiring is an insulating layer so that the wiring on the inner peripheral side included in the divided wiring portion becomes the wiring on the outer peripheral side and the wiring on the outer peripheral side becomes the wiring on the inner peripheral side in the middle of wiring. Spiral inductors that are arranged in a crossover manner through the wiring. In the spiral inductor according to claim 1,
A spiral inductor in which the divided wiring portion is arranged only in the innermost portion of the spiral wiring. In the spiral inductor according to claim 1,
The spiral wiring has a plurality of divided wiring portions having different numbers of divisions in a plan view.
A spiral inductor in which the inner divided wiring portion has a larger number of divisions among the plurality of divided wiring portions. In the spiral inductor according to claim 1,
The outermost wiring portion of the spiral wiring has a plurality of wirings laminated via an insulating layer.
A spiral inductor in which the plurality of stacked wires are connected in series with each other. In addition to including one or more spiral inductors according to any one of claims 1 to 4,
A passive integrated circuit that includes a metal, an insulator, and a capacitor with a metal structure.

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