Spiral Inductor and Passive Integrated Circuit

Abstract

The spiral inductor of the present invention includes a substrate and a spiral wiring disposed on the substrate. A part of the spiral wiring includes a divided wiring portion, and the divided wiring portion is divided into a plurality of mutually parallel wirings when viewed from a top-down perspective. The divided wiring portion is disposed inside the spiral wiring. In the circuit of the divided wiring portion, the wirings inside and outside the divided wiring portion are alternately arranged with a second insulating layer in between, such that the wiring inside the divided wiring portion becomes the wiring on the outside after being staggered, and the wiring on the outside of the divided wiring portion becomes the wiring on the inside after being staggered. The spiral inductor can suppress the skin effect and the proximity effect, and can improve the area utilization efficiency and reduce the series impedance. In addition, the divided wiring portion is alternately arranged through the insulating layer, which can improve the Q value.

Description

Technical Field

[0001] The present invention relates to a high-frequency spiral inductor having a spiral wiring provided on a substrate, and a passive integrated circuit using the spiral inductor. Background Art

[0002] In high-frequency band filters, elastic wave filters such as SAW filters or BAW filters, and passive filters including inductors and capacitors are often used. However, for broadband filters in the high-frequency band around 5 GHz, passive filters are mainly used instead of elastic wave filters. The reason is that although elastic wave filters have a high Q value and very excellent stopband characteristics, it is essentially difficult to broaden their bandwidth.

[0003] The physical shape of a passive filter is a layered structure in which its components are formed by a film-forming technique such as LTCC (low-temperature co-fired ceramic substrate). In addition, there is also a structure in which its components are formed on a wafer plane by a semiconductor process technique similar to that. The latter is generally referred to as IPD (integrated passive device).

[0004] In IPD, the Q values of the inductor and capacitor as components are high, so they are necessarily used for improving low loss and stopband characteristics. Generally, the Q value of a capacitor is several times or more that of an inductor. Therefore, while improving low loss and stopband characteristics, it is also important to increase the Q value of the inductor.

[0005] The thickness of the metal film used in IPD is thinner and the number of layers is smaller than that of the metal film formed by LTCC. Therefore, it is often applied to a structure called a spiral inductor.

[0006] Figures 27 to 29 A spiral inductor widely used in the prior art is formed by providing a spiral wiring 51 on a substrate 50 (for example, see Japanese Patent Application Laid-Open No. 2010-162401). It should be noted that in the case where there are two layers of wiring in this example, as Figure 28 and Figure 29 shown, a double-layer spiral wiring 51 is formed on the substrate 50 through a first insulating layer 52. The spiral wiring 51 in this example has a three-turn structure composed of an outermost wiring portion 51a, an innermost wiring portion 51c, and an intermediate wiring portion 51b. Each of the wiring portions 51a to 51c is kept electrically insulated by a second insulating layer 53. The inner end of the spiral wiring 51 is connected to a terminal lead 54 for connecting to other circuits at a connection portion 55. The outer end of the spiral wiring 51 is connected to a terminal lead 56 for connecting to other circuits.

[0007] In the spiral inductor, the skin effect and proximity effect in the high-frequency band are problems that must be solved. The skin effect described herein refers to the phenomenon that current is only concentrated on the surface of the wiring. Figure 30 Explain the proximity effect. Current Ia and Ib flow through the outer wiring portions 51a and 51b other than the innermost wiring portion 51c, respectively. The generated magnetic flux Φ generates an eddy current Ix in the inner wiring portion 51c. The direction of the eddy current Ix is the same as the direction of the current Ic of the original wiring portion 51c on the inner side 51c1 of the wiring portion 51c, but is opposite on the outer side 51c2 of the wiring portion 51c. Therefore, the current Ic of the inner wiring portion 51c is concentrated in the region marked by the shaded line. As a result, the cross-sectional area where the current actually flows in the wiring portion 51c becomes narrow, resulting in an increase in the series impedance. Therefore, in the spiral inductor, not only the skin effect but also the proximity effect causes an increase in the series impedance of the wiring. The increase in the series impedance will hinder the improvement of the Q value.

[0008] To solve the above problems, the prior art is as Figure 31 shown, the width t1 of the innermost wiring portion 51c is made smaller than the width t2 of the other wiring portion 51b and the width t3 of the wiring portion 51a (t1 < t2 < t3). In this case, a structure is adopted in which the interval between the wirings becomes wider (W1 < W2) in the direction toward the center of the spiral wiring 51.

[0009] Figures 32 to 34 Describe another example of the prior art that can further suppress the skin effect and proximity effect. Figures 32 to 34It shows a simplified structure disclosed in Chinese Utility Model No. 204391102. The structure is formed by dividing all of the spiral wiring 57 formed on the substrate 50 from a top-down perspective (i.e., along the perspective perpendicular to the plane in which the spiral wiring 57 is formed). The example shows a three-turn spiral wiring. In other words, the spiral wiring 57 includes the wiring 57a1 and 57a2 of the outermost divided wiring portion 57a, the wiring 57b1 and 57b2 of the inner divided wiring portion 57b, and the wiring 57c1 and 57c2 of the innermost divided wiring portion 57c. The wiring 57a1 and 57a2 of the outermost divided wiring portion 57a are electrically insulated and staggered at the crossing portion 57x1. Similarly, the wiring 57b1 and 57b2 of the inner divided wiring portion 57b are electrically insulated and staggered from each other at the crossing portion 57x2. And, the wiring 57c1 and 57c2 of the innermost divided wiring portion 57c are electrically insulated and staggered from each other at the crossing portion 57x3. The inner ends of the wiring 57c1 and 57c2 of the innermost divided wiring portion 57c are connected to the terminal lead-out wire 58. And, the outer ends of the wiring 57a1 and 57a2 of the outermost divided wiring portion 57a are connected to the terminal lead-out wire 59 for connecting to other circuits.

[0010] According to the structure of the spiral wiring as Figure 31 shown, the wiring portion 51c with a narrower width can effectively utilize the current path of the conductor and improve the Q value. However, only the innermost wiring portion 51c having a narrower width is not sufficient to suppress the proximity effect, which limits the improvement of the Q value.

[0011] On the other hand, as Figures 32 to 34 shown, the spiral wiring 57 is divided from a top-down perspective, which can reduce the eddy current generated inside the spiral wiring 57 and can improve the Q value more than Figure 31 the spiral inductor. However, a certain distance or more must be ensured between the divided wiring portion 57a, the divided wiring portion 57b, and the divided wiring portion 57c, respectively. In addition, a certain distance or more must be ensured between the wiring 57a1 and 57a2 of each divided wiring portion, between the wiring 57b1 and 57b2, and between the wiring 57c1 and 57c2, respectively. Therefore, in order to ensure the distance, the overall size of the inductor will increase significantly, and since the line width of the outermost divided wiring portion 57a becomes thinner, the series impedance increases, which limits the improvement of the Q value. Summary of the Invention

[0012] In view of the above problems, an object of the present invention is to provide a spiral inductor capable of improving the Q value, and a passive integrated circuit using the spiral inductor.

[0013] One embodiment of the spiral inductor of the present invention includes a substrate and a spiral wiring disposed on the substrate. A part of the spiral wiring includes a divided wiring portion, and the divided wiring portion is divided into a plurality of mutually parallel wirings when viewed from a top view. The divided wiring portion is disposed inside the spiral wiring. In the circuit of the divided wiring portion, the wirings inside and outside the divided wiring portion are alternately disposed with a second insulating layer in between, so that the wiring inside the divided wiring portion becomes the outer wiring after being staggered, and the wiring outside the divided wiring portion becomes the inner wiring after being staggered.

[0014] Therefore, by disposing the divided wiring portion inside the spiral wiring, the eddy current concentrated inside the spiral wiring due to the proximity effect can be reduced, and the increase in the series resistance caused by the proximity effect can be suppressed. Moreover, since the outer wiring portion is not a divided wiring structure, the series resistance in the outer wiring portion does not increase. And, the divided wiring portion can make the series resistance of each wiring of the divided wiring portion almost equal by staggering the inner and outer wirings at the crossing portion. Therefore, the series resistance of the entire winding can be reduced. As a result, a Q value higher than that of the existing spiral inductor can be obtained.

[0015] Another embodiment of the spiral inductor of the present invention is that the spiral wiring is provided with the divided wiring portion at its innermost part.

[0016] Therefore, by only disposing the divided wiring portion at the innermost part of the spiral wiring, the proximity effect can be effectively suppressed. And, since the outer wiring is not provided with a divided wiring portion, the overall spiral wiring can be reduced compared with the case where the outer wiring is divided in the plane. Therefore, in the spiral wiring structure of the present invention, since the wiring can be disposed more efficiently in a limited area, the usage efficiency of the area can be improved, and thus a Q value higher than that of the existing spiral inductor can be obtained.

[0017] Another embodiment of the spiral inductor of the present invention is that the spiral wiring includes a plurality of divided wiring portions with different numbers of divisions when viewed from a top view, and among the divided wiring portions, the divided wiring portion located inside has a larger number of divisions.

[0018] There is a higher magnetic flux density inside the spiral wiring, which generates a stronger proximity effect. Therefore, by providing a plurality of divided wiring portions and increasing the number of divisions in the plane for the divided wiring portions on the inner side, the proximity effect can be suppressed. By arranging the wiring at an appropriate position according to the above-described embodiment, the proximity effect can be suppressed. Therefore, the series impedance of the inner wiring, which is very important in the proximity effect, can be significantly suppressed. Also, by reducing the number of divisions of the divided wiring portions as the influence of the proximity effect decreases, a pattern with high area utilization efficiency can be fabricated. Therefore, by expanding the space, the increase in the series impedance can be mitigated. As a result, a higher Q value than that of the conventional spiral inductor can be obtained. In another embodiment of the spiral inductor of the present invention, in the spiral wiring, the outermost divided wiring portion has a plurality of wirings stacked through an insulating layer, and the stacked wirings are connected in series with each other. Therefore, in the outermost wiring portion, by connecting a plurality of wirings that are electrically insulated from each other in the stacking direction in series, a short metal wire in a narrow space can have a high inductance value and the Q value can be increased.

[0019] In another embodiment of the spiral inductor of the present invention, in the spiral wiring, the outermost divided wiring portion has a plurality of wirings stacked through the second insulating layer, and the stacked wirings are connected in series with each other.

[0020] Therefore, by connecting a plurality of electrically insulated wirings in series in the stacking direction in the outermost wiring portion, a relatively high inductance value can be obtained with a short metal wire in a relatively narrow space, and the Q value can be increased.

[0021] In the spiral inductor of the present invention, the spiral wiring is formed on the substrate through the first insulating layer.

[0022] In the spiral inductor of the present invention, the number of turns of the spiral wiring is greater than or equal to three.

[0023] In the spiral inductor of the present invention, the pitch (tb2) of the parallel wirings of the divided wiring portion is smaller than the pitch (ta2) of the spiral wiring

[0024] In the spiral inductor of the present invention, the staggered position of the divided wiring portion is located in the middle region of the divided wiring portion.

[0025] In the spiral inductor of the present invention, the winding pattern of the spiral wiring is rectangular, rhombic, polygonal, elliptical or circular.

[0026] In one embodiment of the passive integrated circuit of the present invention, it includes at least one spiral inductor and a capacitor having a metal-insulator-metal structure.

[0027] Therefore, by providing the spiral inductor with a high Q value of the present invention in a passive integrated circuit, a circuit with low insertion loss can be obtained. For example, in a passive integrated circuit having a filter, lower insertion loss and excellent stop band characteristics can be obtained.

[0028] The beneficial effects of the present invention are as follows: The spiral inductor can suppress the skin effect and proximity effect, and can improve the area utilization efficiency to reduce the series impedance. In addition, the divided wiring portions are provided alternately through an insulating layer. Therefore, the Q value can be improved. Moreover, the insertion loss of a passive integrated circuit using the spiral inductor of the present invention can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein:

[0030] Figure 1 is a top view of a first embodiment of the spiral inductor of the present invention;

[0031] Figure 2 is Figure 1 a sectional view taken along A-A;

[0032] Figure 3 is Figure 1 a sectional view taken along B-B;

[0033] Figure 4 is Figure 1 a sectional view taken along C-C;

[0034] Figure 5 is Figure 1 a schematic diagram of the inner and outer wiring lengths in the divided wiring portion of;

[0035] Figure 6 is Figure 1 a sectional view of another wiring structure of the spiral inductor of;

[0036] Figure 7 is for use Figure 6 in the case of the wiring structure of, a sectional view of the structure of the crossing portion of the divided wiring;

[0037] Figure 8 is a top view of a second embodiment of the spiral inductor of the present invention;

[0038] Figure 9 is Figure 8 a sectional view taken along D-D;

[0039] Figure 10 is Figure 8 a sectional view taken along E-E;

[0040] Figure 11 isFigure 8 Cross-sectional view along F-F;

[0041] Figure 12 is Figure 8 Schematic diagram of the internal and external wiring lengths in the split wiring section of;

[0042] Figure 13 is Figure 8 Cross-sectional view of another wiring structure of the spiral inductor of;

[0043] Figure 14 is for use in Figure 13 Cross-sectional view of the structure of the intersection of the split wiring in the case of the wiring structure of;

[0044] Figure 15 Top view of the third embodiment of the spiral inductor of the present invention;

[0045] Figure 16 is Figure 15 Cross-sectional view along G-G;

[0046] Figure 17 is Figure 15 Cross-sectional view along H-H;

[0047] Figure 18 is Figure 15 Cross-sectional view along I-I;

[0048] Figure 19 is Figure 15 Cross-sectional view of another wiring structure of the spiral inductor of;

[0049] Figure 20 is for use in Figure 19 Cross-sectional view of the structure of the intersection of the split wiring in the case of the wiring structure of;

[0050] Figure 21 Schematic diagram of the winding pattern of the embodiment of the present invention;

[0051] Figure 22 Schematic diagram of the winding pattern of the comparative example of the present invention;

[0052] Figure 23 Schematic diagram of the winding pattern of the first prior example;

[0053] Figure 24 Schematic diagram of the winding pattern of the second prior example;

[0054] Figure 25 is for an inductor having Figures 21 to 24 Schematic diagram of the change of the Q value corresponding frequency of the inductor with each winding pattern in;

[0055] Figure 26Top view of an embodiment of a passive integrated circuit formed by the spiral inductor of the present invention;

[0056] Figure 27 Top view of an example of a conventional spiral inductor;

[0057] Figure 28 is Figure 27 Cross-sectional view along J-J;

[0058] Figure 29 is Figure 27 Cross-sectional view along K-K;

[0059] Figure 30 Explanation diagram of the proximity effect of the spiral inductor;

[0060] Figure 31 Top view of another example of a conventional spiral inductor;

[0061] Figure 32 Top view of yet another example of a conventional spiral inductor;

[0062] Figure 33 is Figure 32 Cross-sectional view along L-L; and

[0063] Figure 34 is Figure 32 Cross-sectional view along M-M. Detailed Description of the Invention

[0064] The embodiments of the spiral inductor of the present invention are described below. Figures 1 to 7 The first embodiment of the spiral inductor of the present invention is described. The spiral inductor of the first embodiment is formed by forming a spiral wiring 2 on a substrate 1. Preferably, the substrate 1 is made of a material having an impedance value of 1 kΩ·cm or more. Examples of the material of the substrate 1 include high-impedance silicon, gallium arsenide, sapphire, polycrystalline alumina, or glass. However, the substrate 1 used in the present invention is not limited to the above materials.

[0065] In this first embodiment, the spiral wiring 2 is formed on the substrate 1 through a first insulating layer 3. The first insulating layer 3 can be, for example, silicon dioxide. In the case of using a material with a high dielectric constant as the substrate 1, the first insulating layer 3 can be used to reduce the capacitance between the wirings of the spiral wiring 2. Therefore, depending on the material of the substrate 1, the first insulating layer is not necessary. The spiral wiring 2 is kept insulated by a second insulating layer 4 located on the first insulating layer 3. The second insulating layer 4 can be, for example, a polyimide resin or other insulating materials.

[0066] The spiral wiring 2 can generally be made of gold or copper, or a laminated structure of gold and copper, or other metals can be used, and it can also be of other shapes. In this first embodiment, the spiral wiring 2 has three turns. That is, it is composed of the outermost wiring portion 2a of the spiral wiring 2, the middle wiring 2b, and the innermost divided wiring portion 2c. The number of turns of the spiral wiring 2 can also be two turns or four turns or more. And although the winding pattern of the spiral wiring 2 in this first embodiment is a quadrilateral, such as a rectangle, a rhombus, a square, and irregular shapes with four corners, other shapes such as polygons, ellipses, and circles can also be used.

[0067] The innermost divided wiring portion 2c is a part of the spiral wiring 2 and is divided into multiple parts when viewed from a top-down perspective. The divided wiring portion 2c in this first embodiment is divided into two wirings, the first wiring 2c1 and the second wiring 2c2. And in this first embodiment, the line widths of the first wiring 2c1 and the second wiring 2c2 that make up the divided wiring portion 2c are formed such that the line width of the divided wiring portion 2c is narrower than the line widths of the outer wiring portion 2a and the middle wiring portion 2b. The number of divisions of the divided wiring portion 2c can also be three or four. The other wiring portions 2a and 2b do not have a divided structure. And the intervals 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 can be selected as the most appropriate values according to the situation, not limited to the examples in the figure.

[0068] As Figure 2 shown, the wiring portion 2a, the wiring portion 2b, and the divided wiring portion 2c each have a double-layer structure composed of the following wiring 20 and the upper wiring 21. However, as Figure 3 shown, the inner end portion of the spiral wiring 2 is connected to the terminal lead 6 through the connection portion 5. In the overlapping area of the wiring portion 2a and the wiring portion 2b, as well as the terminal lead 6, since the second insulating layer is interposed therebetween, only the upper wiring 21 is provided.

[0069] The first wiring 2c1 and the second wiring 2c2 included in the divided wiring portion 2c are arranged as Figure 1 shown, with their inner and outer positions reversed with the cross portion 2cx as the boundary. In other words, in the divided wiring portion 2, on the side of the connection portion 5a closer to the terminal lead 6 than the cross portion 2cx, a part 2c11 of the first wiring 2c1 is located outside a part 2c21 of the second wiring 2c2. On the other hand, in the divided wiring portion 2, on the side of the connection portion 5b closer to the wiring portion 2b than the cross portion 2cx, the remaining part 2c12 of the first wiring 2c1 is located inside the remaining part 2c22 of the second wiring 2c2.

[0070] Figure 4 A cross-sectional view showing the crossing portion 2cx is presented. In this first embodiment, the lower wiring 20x of the inner wiring 2c21 of the second wiring 2c2 extends outward, and the upper wiring 21 of the outer wiring 2c22 of the second wiring 2c2 is connected to the extended portion. Also, the inner wiring 2c12 of the first wiring 2c1 is formed on the surface of the insulating layer 4. Thereby, the first wiring 2c1 and the second wiring 2c2 are electrically insulated in the crossing portion 2cx. Moreover, the structure of the crossing portion 2cx of the wirings is not limited to this. In the crossing portion, for example, the first wiring 2c1 can be arranged on the lower side and the second wiring on the upper side, etc., and various modifications can be made.

[0071] In the first embodiment, the spiral wiring 2 is quadrilateral. In other words, the divided wiring portion 2c has three corner portions 26, 27, 28 that are bent vertically between the connection portion 5a of the terminal lead-out wire 6 and the connection portion 5b of the wiring portion 2b. Moreover, the crossing portion 2cx is provided at the middle corner portion 27 among the three corner portions 26, 27, 28. Therefore, when the length of the first wiring 2c1 between the connection portion 5a and the connection portion 5b is L1 and the length of the second wiring portion 2c2 is L2, for the following reasons, the lengths of the two are almost equal (L1≈L2).

[0072] In other words, according to Figure 5 , the lengths of the respective sides of the first wiring 2c1 are a1 to a4, and the lengths of the respective sides of the second wiring 2c2 are b1 to b4. Therefore

[0073] L1 = a1 + a2 + a3 + a4...(1)

[0074] L2 = b1 + b2 + b3 + b4...(2)

[0075] It should be noted that the lengths of the respective sides of each wiring are calculated based on the length of the center line portion of the line width of the wiring. Here, since the interval between the first wiring 2c1 and the second wiring 2c2 is almost the same throughout the entire range of the divided wiring portion 2c, therefore

[0076] a2≈b2...(3)

[0077] a3≈b3...(4)

[0078] b1 - a1≈a4 - b4...(5)

[0079] Therefore L1≈L2.

[0080] Thereby, since the length L1 of the first wiring 2c1 and the length L2 of the second wiring 2c2 are almost the same, the series impedance proportional to the wiring length is also almost the same.

[0081] As shown in this first embodiment, by disposing the divided wiring portion 2c divided in parallel inside the spiral wiring 2, the eddy current concentrated on the inner side of the inner wiring due to the proximity effect can be reduced, and the series impedance increased due to the proximity effect can be suppressed. In other words, by dividing the inner wiring portion of the spiral wiring where high magnetic flux density tends to occur and proximity effect is generated into a plurality of inner wirings 2c1 and outer wirings 2c2, the eddy current generated in the wiring can be reduced.

[0082] In addition, since the first wiring 2c1 and the second wiring 2c2 of the divided wiring portion 2c are staggered at the crossing portion 2cx, the side lengths of the first wiring 2c1 and the second wiring 2c2 are almost the same, and their series impedances are almost the same. Therefore, the current in the first wiring 2c1 and the second wiring 2c2 does not tend to either side, and the series impedance of the divided wiring portion 2c can be reduced.

[0083] Moreover, since the outer wiring portions 2a and 2b are not divided, the width of the wiring can be sufficiently ensured in a limited space, and the series impedance can be reduced. Therefore, compared with the case where the outer wiring portions 2a and 2b are divided, the area utilization efficiency is higher, and the overall wiring portion can be reduced. Therefore, by disposing the divided wiring portion 2c inside to decrease the series impedance, the spiral inductor can obtain a higher Q value than the conventional spiral inductor.

[0084] Figure 6 Yes Figure 2 It is a modified example of the wiring structure shown. The wiring structure of this modified example is provided with a second insulating layer 4 in all regions between the lower wiring 20 and the upper wiring 21 of the wiring portion 2a, the wiring portion 2b, and the divided wiring portion 2c. However, at the connection portion 5a where the inner end portion of the spiral wiring 2 is connected to the terminal lead wire 6, the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2c are connected. Also, the lower wiring 20 and the upper wiring 21 of the wiring portion 2a and the wiring portion 2b are connected in the vicinity of the region where they cross the terminal lead wire 6. Moreover, for the terminal lead wire 7 at the other end of the spiral wiring 2, the lower wiring 20 and the upper wiring 21 of the wiring portion 2a are connected.

[0085] Figure 7 Shows Figure 6 the wiring structure shown, that is, the structure of the crossing portion 2cx in the case of adopting a structure in which the upper and lower wirings are separated from each other by an insulating layer. In the structure of the crossing portion 2cx, the upper wiring 21 and the lower wiring 20x of the inner wiring 2c21 of the second wiring 2c2 are connected by a longitudinal wiring 20y.

[0086] As Figure 6As shown, the lower wiring 20 and the upper wiring 21 of the spiral wiring 2 are provided with an insulating layer 4, which can split the current flowing through the spiral wiring 2 into the lower wiring 20 and the upper wiring 21. Therefore, by increasing the path of the current, the skin effect can be slowed down, the cross-sectional area of the current flow can be substantially increased, and the series impedance can be reduced. Therefore, the Q value can be further improved.

[0087] Figures 8 to 14 Describe the second embodiment of the spiral inductor of the present invention. In this second embodiment, the spiral wiring 2A includes the outermost wiring portion 2d, the divided wiring portion 2e in the middle portion, and the divided wiring portion 2f in the innermost portion. The divided wiring portion 2e in the middle portion is composed of a first wiring 2e1 and a second wiring 2e2 connected in parallel with each other. The divided wiring portion 2f in the innermost portion is composed of a first wiring 2f1, a second wiring 2f2, a third wiring 2f3, and a fourth wiring 2f4 connected in parallel with each other.

[0088] As Figure 9 shown, the wiring portion 2d, the wiring portion 2e, and the wiring portion 2f are also composed of the stacked lower wiring 20 and upper wiring 21 as in the first embodiment. And, as Figure 10 shown, the connection structure between the terminal lead 6 and the connection portion 5c is the same as that in the first embodiment. Moreover, the structure of the intersection of the terminal lead 6 and the wiring portion 2d and the divided wiring portion 2e is also provided with an insulating layer 4 like the structure of the intersection of the terminal lead 6 and the wiring portion 2a and the divided wiring portion 2b in the first embodiment.

[0089] In this second embodiment, the line widths of the first wiring 2e1 and the second wiring 2e2 constituting the divided wiring portion 2e are 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 narrower than the line widths of the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e. In other words, in the spiral wiring 2A, the line width of the innermost wiring portion is narrower.

[0090] One end of each of the four wirings 2f1 to 2f4 included in the divided wiring portion 2f is all connected to the connection portion 5c of the terminal lead 6. Among the four wirings 2f1 to 2f4, the other ends of the first wiring 2f1 and the second wiring 2f2 located inside are connected to the second wiring 2e2 constituting the divided wiring portion 2e at the connection portion 5d. On the other hand, among the four wirings 2f1 to 2f4, the other ends of the third wiring 2f3 and the fourth wiring 2f4 located outside are connected to the first wiring 2e1 constituting the divided wiring portion 2e at the connection portion 5e.

[0091] The first wiring 2e1 and the second wiring 2e2 of the middle split wiring section 2e are arranged such that their positions inside and outside are reversed with the crossing section 2ex as the boundary. In other words, between the crossing section 2ex and the connection sections 5d and 5e connecting to the split wiring section 2f, a part 2e11 of the first wiring 2e1 of the split wiring section 2e is located outside a part 2e21 of the second wiring 2e2. On the other hand, in the split wiring section 2e, between the crossing section 2ex and the connection section 5f connecting to the wiring section 2d, the remaining part 2e12 of the first wiring 2e1 is located inside the remaining part 2e22 of the second wiring 2e2.

[0092] In the innermost split wiring section 2f, the first wiring 2f1 and the second wiring 2f2 are arranged such that their positions inside and outside are reversed with the crossing section 2fx1 as the boundary. In other words, between the crossing section 2fx1 and the connection section 5c connecting to the terminal lead-out wire 6, a part 2f11 of the first wiring 2f1 is located outside a part 2f21 of the second wiring 2f2. On the other hand, between the crossing section 2fx1 and the connection section 5d connecting to the second wiring 2e2 of the split wiring section 2e, the remaining part 2f12 of the first wiring 2f1 is located at a position inside the remaining part 2f22 of the second wiring 2f2.

[0093] In the innermost split wiring section, the third wiring 2f3 and the fourth wiring 2f4 are arranged such that their positions inside and outside are reversed with the crossing section 2fx2 as the boundary. In other words, between the crossing section 2fx2 and the connection section 5c connecting to the terminal lead-out wire 6, a part 2f31 of the third wiring 2f3 is located outside a part 2f41 of the fourth wiring 2f4. On the other hand, between the crossing section 2fx2 and the connection section 5e connecting to the first wiring 2e1 of the split wiring section 2e, the remaining part 2f32 of the third wiring 2f3 is located at a position inside the remaining part 2f42 of the fourth wiring 2f4.

[0094] Figure 11 Describe the cross-sectional structure of the crossing section 2fx1 of the first wiring 2f1 and the second wiring 2f2. As shown in the figure, the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 extends outward, and the upper wiring 21 of the outer wiring 2f22 of the second wiring 2f2 is connected to the extended part. And the inner wiring 2f12 of the first wiring 2f1 is formed on the surface of the insulating layer 4. Therefore, there is electrical insulation between the first wiring 2f1 and the second wiring 2f2. The crossing section 2fx2 and the crossing section 2ex also have the same cross-sectional structure, and the illustration is omitted.

[0095] In Figure 8 In the wiring structure having the crossing section 2fx1, the series impedance of the first wiring 2f1 and the second wiring 2f2 in the split wiring section 2f, as in Figure 1The reasons described in [reference] can be made almost the same by the provision of the crossover section 2fx1. Similarly, the series impedance of the third wiring 2f3 and the fourth wiring 2f4 in the divided wiring section 2f can be made almost the same by the provision of the crossover section 2fx2, as described in Figure 1 [reference].

[0096] Here, in the divided wiring section 2f, the average length of the inner first wiring 2f1 and second wiring 2f2 is summarized as L(f12), and the average length of the outer third wiring 2f3 and fourth wiring 2f4 is summarized as L(f34). Since the third wiring 2f3 and the fourth wiring 2f4 are outside the first wiring 2f1 and the second wiring 2f2,

[0097] L(f12) < L(f34) … (7)

[0098] Therefore, due to the difference between the length L(f12) and the length L(f34), there is also a difference in the series impedance between the inner wirings 2f1, 2f2 and the outer wirings 2f3, 2f4. However, for the above difference in series impedance, it can be reduced or eliminated by adjusting the lengths of the first wiring 2e1 and the second wiring 2e2 of the divided wiring section 2e that are respectively connected to the inner wirings 2f1, 2f2 and the outer wirings 2f3, 2f4. Next, the adjustment of the length difference of the wirings will be described.

[0099] Figure 12 Describe the wiring lengths of the divided wiring section 2e and the divided wiring section 2f. In Figure 12 [reference], the lengths c1, c2, c3, and c4 of each side of the inner first wiring 2f1 and second wiring 2f2 of the divided wiring section 2f are calculated based on the length of the center line of the groove between the first wiring 2f1 and the second wiring 2f2. Similarly, the lengths d1, d2, d3, and d4 of each side of the outer third wiring 2f3 and fourth wiring 2f4 of the divided wiring section 2f are calculated based on the length of the center line of the groove between the third wiring 2f3 and the fourth wiring 2f4. Here, the length of the inner first wiring 2f1 and second wiring 2f2 of the divided wiring section 2f is summarized as L(f12). And the length of the outer third wiring 2f3 and fourth wiring 2f4 is summarized as L(f34).

[0100] The above lengths L(f12) and L(f34) are respectively expressed by the following formulas.

[0101] L(f12) = c1 + c2 + c3 + c4 … (8)

[0102] L(f34) = d1 + d2 + d3 + d4 … (9)

[0103] 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, e2, e3, and e4 and f1, f2, f3, and f4 of the respective sides of the respective wirings 2e1 and 2e2 are calculated as the lengths of the center line portions of the line widths of the wirings. 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 formulas.

[0104] L(2e1) = e1 + e2 + e3 + e4…(10)

[0105] L(2e2) = f1 + f2 + f3 + f4…(11)

[0106] And,

[0107] L(f34) - L(f12) ≈ L(2e2) - L(2e1)…(12)

[0108] The lengths of the wirings and the intervals of the grooves between the wirings are designed as follows. In other words, the difference between the average lengths of the third wiring 2f3 and the fourth wiring 2f4 of the divided wiring portion 2f and the average lengths of the first wiring 2f1 and the second wiring 2f2 is absorbed by the length difference between the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e.

[0109] As shown in this second embodiment, by providing a plurality of divided wiring portions with different numbers of divisions and increasing the number of divisions of the inner divided wiring portion on the plane, while suppressing the proximity effect, arranging the wiring portion at a suitable position can better suppress the proximity effect. Therefore, the inner divided wiring portion 2e and the divided wiring portion 2f are very important for suppressing the proximity effect and can substantially reduce the series impedance. And, by reducing the number of divisions of the divided wiring portion 2e and the divided wiring portion 2f as the influence degree of the proximity effect decreases, a pattern with high area utilization efficiency can be fabricated. Therefore, the increase in the series impedance can be slowed down by expanding the space.

[0110] Moreover, the divided wiring portion 2e and the divided wiring portion 2f are staggered at the crossing portion 2ex and the crossing portions 2fx1 and 2fx2. Therefore, the lengths of the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e can be made almost the same, the lengths of the first wiring 2f1 and the second wiring 2f2 of the divided wiring portion 2f can be made almost the same, and the lengths of the third wiring 2f3 and the fourth wiring 2f4 can be made almost the same. Therefore, the series impedances of these can be made almost equal.

[0111] Moreover, the difference in the average lengths of the third wiring 2f3 and the fourth wiring 2f4 of the divided wiring portion 2f, as compared with the average lengths of the first wiring 2f1 and the second wiring 2f2 of the divided wiring portion 2f, is absorbed by the length difference between the first wiring 2e1 and the second wiring 2e2 of the divided wiring portion 2e. Therefore, by designing the number of divisions of the divided wiring portion 2f to be four, the difference in series impedance caused by the difference in the lengths of the internal and external wirings can be eliminated or reduced.

[0112] Due to the above reasons, a higher Q value can be obtained compared with existing spiral inductors.

[0113] Figure 13 Yes Figure 9 A modified example of the wiring portion structure shown in FIG. An insulating layer 4 is provided in all regions between the lower wiring 20 and the upper wiring 21 of the wiring portion 2d, the divided wiring portion 2e, and the divided wiring portion 2f. However, as shown in FIG. Figure 10 As shown, at least at the connection portion 5c of the terminal lead 6 connecting the inner ends of the spiral wirings, the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2f are connected. Also, in the vicinity of the region where the wiring portion 2d and the divided wiring portion 2e intersect with the terminal lead 6, the lower wiring 20 and the upper wiring 21 are connected. Also, for the terminal lead 7 located at the other end of the spiral wiring, the lower wiring 20 and the upper wiring 21 of the wiring portion 2d are connected.

[0114] As Figure 13 As shown, an insulating layer 4 is provided between the lower wiring 20 and the upper wiring 21 of the spiral wiring, enabling the current flowing in the spiral wiring to be shunted to the lower wiring 20 and the upper wiring 21. Therefore, the skin effect can be mitigated, the cross-sectional area through which the current flows can be substantially increased, and the series impedance can be reduced. As a result, the Q value can be further increased.

[0115] Figure 14 Is Figure 13 The cross-sectional structure of the crossing portion 2fx1 of the first wiring 2f1 and the second wiring 2f2 in the divided wiring portion 2f in the wiring structure shown in FIG. As shown in the figure, the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 extends outward, and the extended portion is connected to the upper wiring 21 of the outer wiring 2f22 of the second wiring 2f2. Also, the inner wiring 2f12 of the first wiring 2f1 is formed on the surface of the insulating layer 4. Thereby, the first wiring 2f1 and the second wiring 2f2 are electrically insulated in the crossing portion 2fx1. The upper wiring 21 and the lower wiring 20x of the inner wiring 2f21 of the second wiring 2f2 are connected by a longitudinal wiring 20y. The crossing portion 2fx2 and the crossing portion 2ex also have the same cross-sectional structure.

[0116] Figures 15 to 20Describe the third embodiment of the spiral inductor. In the third embodiment, the outermost wiring portion 2g of the spiral wiring 2B has a plurality of wirings laminated by an insulating layer 4. In the third embodiment, it is shown that the wiring has a lower wiring 22 and an upper wiring 23. The end of the lower wiring 22 and the terminal portion 23b of the upper wiring 23 are connected in series at the connection portion 24. As Figure 17 shown, in the upper wiring 23 of the wiring portion 2g, the outermost terminal portion 23b and the inner wire portion 23a are alternately arranged with a separation of the insulating layer 4 from the terminal lead 6. It should be noted that the wirings constituting the outermost wiring portion 2g are not limited to the upper and lower two layers in the example, and may be three or more layers.

[0117] As Figure 15 and Figure 16 shown, the inner wiring portion of the spiral wiring 2B is composed of a divided wiring portion 2h. In other words, the inner divided wiring portion 2h is divided into an inner wiring 2h1 and an outer wiring 2h2. One end of either the inner wiring 2h1 or the outer wiring 2h2 is connected to the connection portion 5 of the terminal lead 6. The other end of the inner wiring 2h1 and the outer wiring 2h2 is connected to the connection portion 25 of the upper wiring 23 of the wiring portion 2g. It should be noted that the number of divisions of the wiring in the divided wiring portion 2h is not limited to two, and may be three or more.

[0118] The current path of the spiral wiring 2B is in sequence: terminal lead 6 - connection portion 5 - divided wiring portion 2h (2h11 and 2h22) - connection portion 25 - upper wiring 23 of the wiring portion 2g - connection portion 24 - lower wiring 22 of the wiring portion 2g - terminal lead 7.

[0119] Figure 18 is a cross-sectional view of the cross portion 2hx. In this third embodiment, the lower wiring 20x of the second wiring 2h22 extends outward, and the upper wiring 21 of the second wiring 2h21 is connected to the extended portion. And, the first wiring 2h11 is formed on the surface of the insulating layer 4. Thereby, the first wiring 2h11 and the second wiring 2h21 are electrically insulated in the cross portion 2hx.

[0120] In the third embodiment, a plurality of lower wirings 22 and upper wirings 23 constitute the outer wiring portion 2g, and the wirings are connected in series, so that the same inductance can be obtained with a shorter wiring length in a relatively narrow space, thereby improving the Q value. And, in this third embodiment, because the cross portion 2hx is provided in the divided wiring portion 2h, the Q value can be further improved.

[0121] Figure 19 is as Figure 16 shown, which is a variation example of the wiring structure. An insulating layer 4 is provided between the lower wiring 20 and the upper wiring 21 of the divided wiring portion 2h. However, as Figure 17As shown, at least in the region of the connection part 5 connecting the terminal lead-out wire 6 to the inner end part of the spiral wiring 2B, the lower wiring 20 of the divided wiring part 2h is connected to the upper wiring 21.

[0122] Figure 20 This is a cross-sectional structure of the crossing part 2hx. In the structure of the crossing part 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 longitudinal wiring 20y.

[0123] As Figure 19 shown, an insulating layer 4 is provided between the lower wiring 20 and the upper wiring 21 of the divided wiring part 2h, and the current flowing in the divided wiring part 2h can be shunted to the lower wiring 20 and the upper wiring 21. Therefore, the skin effect can be alleviated, the cross-sectional area of current flow can be substantially increased, and the series impedance can be reduced. Therefore, the Q value can be further increased.

[0124] Figures 21 to 24 This is a schematic diagram of the winding patterns of the spiral inductors of the embodiment of the present invention, the comparative example, and two existing examples for comparison in order to study the improvement of the Q value of the present invention. In Figure 21 it, the embodiment of the present invention includes a divided wiring part 2c having inner and outer wirings at the innermost side, and a crossing part 2x located at the divided wiring part 2c. In the said embodiment, there is a winding structure as Figure 1 shown. In Figure 22 it, although the comparative example has the same divided wiring part as the said embodiment, it does not have the crossing part 2x. In Figure 23 it, the first existing example corresponds to the winding structure as Figures 27 to 28 shown. In Figure 24 it, the second existing example corresponds to the winding structure as Figures 32 to 33 shown.

[0125] In Figures 21 to 24 it, in the embodiment of the present invention, the comparative example, and the two existing examples, the substrate is a gallium arsenide substrate, and the material of the winding is gold. Moreover, the number of winding turns (but one turn for each divided wiring part) is three, the overall width W1 of the winding part is 200 μm, and the width W2 of the innermost winding is 100 μm. And, the width ta1 of the wider wirings 2a, 2b, 51a, 51b, and 51c is 25 μm. Moreover, the interval ta2 of the winding part is 15 μm. And, in the divided wiring parts 2c, 57a - 57c, the width tb1 of the wiring is 10 μm, and the interval tb2 of the wiring is 5 μm. Moreover, the thickness of all the wirings is 10 μm.

[0126] Figure 25 This is a schematic diagram of the change of the Q value of the inductor having each winding pattern in Figures 21 to 24 with respect to the frequency. As Figure 25As shown, the frequency band generally used or intended for use in mobile communication devices is 2.0 to 5.5 GHz. In the embodiment (A) of the present invention, compared with the comparative example (B), the first prior art example (C), and the second prior art example (D), it has a higher Q value.

[0127] Figure 26 This is an embodiment of a passive integrated circuit composed of the spiral inductor of the present invention. In Figure 26 it, the spiral inductor has the structure of the present invention. That is to say, the inner wiring of the spiral inductor 9 is constituted by a divided wiring portion 90 formed by a first wiring 90a and a second wiring 90b. The first wiring 90a and the second wiring 90y are alternately arranged with an insulating layer interposed therebetween at the crossing portion 90x. Figure 26 The filter 12 as a passive integrated circuit of [[ID=]] 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) through a connection wire 11a. The other end of the spiral inductor 9 is connected to another MIM capacitor 10X through a connection wire 11b. One end of the spiral inductor 9X is connected to the capacitor 10 through a connection wire 11c. The other end of the spiral inductor 9X is connected to the capacitor 10X through a connection wire 11d.

[0128] Therefore, the passive integrated circuit of the present invention includes at least one spiral inductor 9 and capacitor 10 of the present invention. Therefore, by means of the spiral inductor 9 with a higher Q value of the present invention, a passive integrated circuit with low insertion loss can be realized. As shown in the figure, the filter 12 using the spiral inductor of the present invention can have a lower insertion loss and excellent stop band characteristics. In addition to filters in passive integrated circuits, it is also helpful for improving the functions such as baluns (balun), duplexers (signal separation in high-frequency and low-frequency bands), and impedance matching.

[0129] The above are only embodiments of the present invention, and the scope of implementation of the present invention cannot be limited thereby. That is, all simple equivalent changes and modifications made according to the claims and the content of the specification of the present invention still belong to the scope of the present invention.

Claims

1. A spiral inductor, characterized in that: the spiral inductor includes a substrate and a spiral wiring disposed on the substrate, a part of the spiral wiring includes a split wiring portion, the split wiring portion is split into a plurality of mutually parallel wirings when viewed from a top-down perspective, the split wiring portion is disposed inside the spiral wiring, in the circuit of the split wiring portion, the wirings inside and outside the split wiring portion are alternately arranged with a second insulating layer in between, so that the wiring inside the split wiring portion becomes the outer wiring after being staggered, and the wiring outside the split wiring portion becomes the inner wiring after being staggered; the spiral wiring includes an outermost wiring portion, a split wiring portion in the middle portion, and an innermost split wiring portion; the wiring of the outermost wiring portion is not split; the split wiring portion in the middle portion is composed of two mutually parallel wirings; the line width of the wiring of the split wiring portion in the middle portion is narrower than the line width of the wiring of the outermost wiring portion; the innermost split wiring portion starts to split from the inner end of each wiring of the split wiring portion in the middle portion, forming four mutually parallel wirings; the line width of the wiring of the innermost split wiring portion is narrower than the line width of the wiring of the split wiring portion in the middle portion.

2. The spiral inductor according to claim 1, characterized in that: the spiral wiring includes an upper wiring and a lower wiring, and the second insulating layer is disposed between the upper wiring and the lower wiring.

3. The spiral inductor according to claim 1, characterized in that: in the spiral wiring, the outermost split wiring portion has a plurality of wirings stacked through the second insulating layer, and the stacked wirings are connected in series with each other.

4. The spiral inductor according to claim 1, characterized in that: the spiral wiring is formed on the substrate through a first insulating layer.

5. The spiral inductor according to claim 1, characterized in that: the number of turns of the spiral wiring is greater than or equal to three.

6. The spiral inductor according to claim 1, characterized in that: the spacing between the parallel wirings of the split wiring portion is smaller than the spacing of the spiral wiring.

7. The spiral inductor according to claim 1, characterized in that: the staggered position of the split wiring portion is located in the middle area of the split wiring portion.

8. The spiral inductor according to claim 1, characterized in that: the winding pattern of the spiral wiring is a polygon, an ellipse or a circle.

9. A passive integrated circuit, characterized in that: the passive integrated circuit includes at least one spiral inductor according to any one of claims 1 to 8, and a capacitor having a metal-insulator-metal structure.

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