Electronic Circuits and Circuit Boards

Abstract

To provide an electronic circuit that is reduced in size by making good use of interaction between adjacently arrayed structures, and a circuit board.SOLUTION: An EBG (Electromagnetic Band Gap) structure comprises a ground 11, a stub 13 formed in a different conductor layer from the ground 11, and a via 12 connecting the ground 11 and the stub 13. Further, the unit circuits constituting the EBG structure are each provided with a via 14 connecting with the stub 13 at a plurality of places where the stub 13 extends halfway. Unlike the via 12, the vias 14 are not connected to the ground 11. The vias 14 which are not connected to the ground 11 are arranged at adjacent positions not across a conductor line of the stub 13 when the plurality of unit circuits are arrayed.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to electronic circuits and circuit boards. [Background technology]

[0002] There is a known technology that suppresses the propagation of electromagnetic noise by using an EBG (Electromagnetic Band Gap) structure formed on a circuit board. Since an EBG structure requires a large area on the circuit board and multiple identical structures are arranged, miniaturization is one of the challenges.

[0003] For example, Patent Document 1 proposes an EBG structure that is miniaturized by forming spiral-shaped conductor lines in two layers and connecting them with vias.

[0004] Furthermore, Patent Document 2 proposes an EBG structure that is miniaturized by forming a third layer in addition to a layer in which a conductor line is formed and a ground layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-134809 A [Patent Document 2] JP 2013-255259 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an electronic circuit and a circuit board that are miniaturized by utilizing the interaction between adjacently arranged structures. [Means for solving the problem]

[0007] First aspect The invention relates to a plurality of discrete electronic circuits arranged in an array, each of the plurality of discrete electronic circuits comprising: When the conductor layer is connected to the ground of any one of the first layers among the multiple laminated conductor layers and extends in the lamination direction, In a second layer of the plurality of conductor layers, which is different from the first layer, The first conductive pillar It is connected to the The first conductive pillar a conductor line having an open end at an end remote from the a second conductor post extending in the lamination direction, the second conductor post being connected to the conductor line and not connected to ground; Each of the first and second adjacent individual electronic circuits among the plurality of individual electronic circuits has a first individual electronic circuit and a second individual electronic circuit between them. Individual Electronics The electronic circuit is characterized by having at least a pair of the second conductor columns formed in adjacent positions without sandwiching any of the conductor lines of the circuit.

[0008] Second aspect The present invention is characterized in that the plurality of individual electronic circuits are circuits for suppressing at least one electromagnetic noise of the same frequency. First aspect 2 is an electronic circuit according to the first embodiment.

[0009] Third aspect The present invention relates to a method for manufacturing a semiconductor device, comprising: providing a conductor line of each of the plurality of individual electronic circuits, the conductor line being provided with an end portion different from the open end of the conductor line; No. 1 It is characterized in that it is a line connected to a conductor pole. Second aspect 2 is an electronic circuit according to the present invention.

[0010] Fourth Aspect The present invention is characterized in that the conductor line extends while bending continuously or intermittently in the same rotation direction from one end to the other end. Third aspect 2 is an electronic circuit according to the first embodiment.

[0011] Fifth Aspect The invention relates to First aspect from Fourth Aspect Of Any one of the following 2. A circuit board comprising the electronic circuit according to claim 1 mounted thereon. Effect of the Invention

[0012] First aspect and Second aspect The electronic circuit, Fifth Aspect According to this circuit board, miniaturization can be achieved.

[0013] Third aspect According to the electronic circuit, for the same conductor line length, the frequency band of electromagnetic noise whose propagation is suppressed can be reduced to the maximum.

[0014] Fourth Aspect The electronic circuit of this embodiment is smaller in size than a non-spiral shape. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing an example of one unit circuit constituting a conventional EBG structure. [Diagram 2] FIG. 1 is a diagram showing a distributed constant circuit that is an equivalent circuit of an EBG structure. [Diagram 3] FIG. 13 is a diagram showing frequency characteristics of admittance Y. [Figure 4] FIG. 1 is a diagram illustrating a transmission characteristic versus frequency. [Diagram 5] 1A to 1C are schematic diagrams showing EBG structures of various shapes. [Figure 6] 1 is a diagram showing a circuit for one unit of an EBG structure constituting an electronic circuit according to a first embodiment of the present invention. [Figure 7] FIG. 7 is a schematic diagram showing an EBG structure in which four one-unit circuits shown in FIG. 6 are arranged. [Figure 8] This is a diagram showing a distributed constant circuit, which is an equivalent circuit of the EBG structure when a via that acts as a capacitor is added. [Figure 9] 13A and 13B are diagrams for explaining the effect of adding a pair of adjacent vias between adjacent unit circuits. [Figure 10] 1A to 1C are plan views of EBG structures according to various embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Here, we will first explain the EBG structure (Electromagnetic Band Gap Structure). The EBG structure is a periodic structure with a frequency band (band gap) that suppresses the propagation of electromagnetic waves. By forming an EBG structure near an electronic circuit that emits electromagnetic noise on a circuit board, the propagation of the electromagnetic noise emitted from the electronic circuit is suppressed.

[0017] FIG. 1 is a schematic diagram showing an example of one unit circuit constituting a conventional EBG structure.

[0018] Here, a circuit board having multiple conductor layers is used, and a first layer of the multiple layers is a ground 11. A conductor column called a via 12 is formed here, which is connected to the ground 11 of the first layer and extends in the stacking direction. A conductor line called a stub 13 is formed here, which extends in a spiral shape in a second layer different from the first layer. One end 13a of the stub 13 is connected to the via 12. An end 13b of the stub 13, which is away from the via 12, is an open end that is not directly connected to other conductors. An EBG structure is formed by arranging a plurality of unit structures such as those shown in FIG. 1 on a circuit board.

[0019] 1 is not a spiral shape made up of curves, but a conductor line that extends from one end connected to via 12 to the other end while bending intermittently in the same rotational direction. Specifically, stub 13 is a conductor line that extends while bending intermittently at 90° increments in the same rotational direction. Here, the term "spiral shape" includes not only a spiral shape made up of a continuous curve, but also a shape that extends while bending intermittently, for example, at 45° or 90° increments.

[0020] FIG. 2 is a diagram showing a distributed constant circuit that is an equivalent circuit of the EBG structure.

[0021] The equivalent circuit of the EBG structure is expressed as the distributed constant circuit shown in Figure 2. Here, inductance L1 and capacitance C1 are the inductance and capacitance of the transmission path, respectively. Of these, inductance L1 is not very related to the frequency characteristics that suppress electromagnetic noise radio waves, while the part surrounded by the dashed line is related to those frequency characteristics. The admittance Y of the part surrounded by the dashed line is given by

[0022]

number

[0023] Fig. 3 is a diagram showing the frequency characteristics of admittance Y. The vertical axis of Fig. 3 represents the imaginary component Im(Y) of admittance Y, and the horizontal axis represents frequency (GHz).

[0024] The negative region of Im(Y), shown with hatching in Figure 3, is called the inductance region, and the positive region is called the capacitance region. In this EBG structure, the propagation of electromagnetic noise with frequencies within the inductance region, that is, the frequency region where Im(Y) is negative, is suppressed.

[0025] Here, the frequency range in which Im(Y) is negative is related to the length of stub 13; the longer the length of stub 13, the more the frequency characteristic pattern shifts to the lower frequency side, and the shorter the length of stub 13, the more the frequency characteristic pattern shifts to the higher frequency side.

[0026] Fig. 4 is a diagram showing a schematic diagram of the transmission characteristic with respect to frequency. In Fig. 4, the lower the transmission characteristic, the more the noise propagation is suppressed.

[0027] The center frequency f0 at which noise propagation is suppressed is roughly

[0028]

number

[0029] In Figure 4, if graph A is considered as the standard, a short stub will shift the frequency at which noise propagation is suppressed to the higher frequency side as shown in graph B, while a long stub will shift the frequency at which noise propagation is suppressed to the lower frequency side as shown in graph C. This means that a long stub is required to suppress the propagation of low-frequency noise, which requires a large area. For this reason, there is a demand for miniaturizing the EBG structure.

[0030] FIG. 5 is a schematic diagram showing EBG structures of various shapes.

[0031] Fig. 5(A) shows an EBG structure in which multiple units each having the spiral-shaped stub 13 described above are arranged. As in Fig. 1, the stub 13 shown here is a conductor line that extends from one end connected to the via 12 to the other end while intermittently bending at 90° in the same direction of rotation, but the EBG structure can be formed in any spiral shape as long as it is a spiral shape as defined above.

[0032] 5B shows an EBG structure in which a plurality of units each having a so-called meander-shaped stub 13 that extends back and forth from side to side are arranged. In this Fig. 5B, a meander shape is shown in which the direction of extension is reversed by bending twice at 90° in the same rotation direction, but the present invention is not limited to this. For example, the shape may be reversed while drawing a curve, or the shape may be reversed by bending four times at 45°. One end 13a of the stub 13 of each unit is connected to the via 12 of each unit. Each stub 13 extends in a meander shape, and the end 13b on the side away from the via 12 is an open end.

[0033] 5(C) shows an EBG structure in which a plurality of units are arranged, each having a linearly extending stub 13. One end 13a of the stub 13 of each unit is connected to the via 12 of each unit. Each stub 13 extends linearly, and the end 13b on the side away from the via 12 is an open end.

[0034] As shown in these examples, stubs 13 of various shapes can be used in the EBG structure. However, the length from the point where stub 13 is connected to via 12 to the open end is related to the frequency of the noise whose propagation is suppressed, and a long stub is required to suppress low-frequency noise. Therefore, in order to suppress low-frequency noise, it is advantageous in terms of miniaturization to form stub 13 connected to via 12 at one end 13a.

[0035] Based on the above explanation of the EBG structure, an embodiment of the present invention will be described below.

[0036] FIG. 6 is a diagram showing a circuit for one unit of an EBG structure constituting an electronic circuit according to a first embodiment of the present invention.

[0037] Moreover, Fig. 7 is a schematic diagram showing an EBG structure in which four unit circuits shown in Fig. 6 are arranged side by side. Here, Fig. 7(A) is a schematic cross-sectional view, and Fig. 7(B) is a schematic plan view.

[0038] Here, as in the conventional example shown in FIG. 1, a circuit board 10 having a plurality of conductor layers is adopted, and the first layer of the plurality of layers is the ground 11. Here, a conductor column called a via 12 is formed, which is connected to the first layer, the ground 11, and extends in the stacking direction. Here, a conductor line called a stub 13 is formed in a second layer different from the first layer, and extends in a spiral shape. In this embodiment, a spiral shape that extends while changing direction by 90° is adopted as this conductor line. However, it is not limited to a spiral shape that extends while changing direction by 90°, and it is sufficient that the conductor line extends while bending continuously or intermittently in the same rotation direction from one end to the other end as defined above.

[0039] In the circuit for one unit shown in Fig. 6, vias 14 are provided at multiple points along the extension of stub 13, and extend in the lamination direction and are connected to stub 13. However, as shown in Fig. 7(A), these vias 14 are not connected to ground 11, unlike via 12 at the center of the spiral. Via 12 at the center of the spiral and connected to both stub 13 and ground 11 corresponds to an example of the first conductive pillar according to the present invention, and the other vias 14 connected to stub 13 and not connected to ground 11 correspond to an example of the second conductive pillar according to the present invention.

[0040] Here, as shown in FIG. 7B, when a plurality of unit circuits are arranged, the vias 14 not connected to the ground 11 are arranged at adjacent positions without sandwiching the conductor line of the stub 13 between them. However, since unit circuits of the same shape are arranged here, the unit circuits arranged at the corners do not have unit circuits next to them, and some vias 14 do not have a pair. The adjacent vias 14 of two adjacent unit circuits act as a capacitor, and a capacitance is generated there. If the two vias 14 are separated so that the conductor line of the stub 13 is placed between them, a sufficient capacitance cannot be generated, so it is preferable that the two vias 14 are close enough to each other that the conductor line of the stub 13 is not placed between them.

[0041] FIG. 8 is a diagram showing a distributed constant circuit that is an equivalent circuit of the EBG structure when a via that acts as a capacitor is added.

[0042] In FIG. 8, a capacitor C2 is added compared to the distributed constant circuit that is the equivalent circuit of the conventional EBG structure shown in FIG.

[0043] The admittance Y of the part enclosed by the dashed line in this equivalent circuit is

[0044]

number

[0045] Figure 9 is a diagram illustrating the effect of adding a pair of adjacent vias between adjacent unit circuits. The horizontal axis of Figure 9 (A) and (B) represents frequency, and the vertical axis represents transmission characteristics. Here, the lower the transmission characteristics, the more the noise propagation is hindered.

[0046] According to the imaginary part Im(Y) of admittance Y expressed by (1) above, calculated from the equivalent circuit of a conventional EBG structure, the transmission characteristics are expressed, for example, as shown in graph A in Figure 9(A). Here, we are trying to block the propagation of noise with a center frequency of f0.

[0047] When vias 14 are formed close to each other in adjacent unit circuits, the transmission characteristics are expressed, for example, as graph D in Fig. 9(A) according to the imaginary part Im(Y) of admittance Y expressed by the above formula (3). That is, the frequency band in which noise propagation can be blocked is expanded.

[0048] Therefore, we consider forming the vias 14 to widen the frequency band and then miniaturizing the EBG structure. When miniaturized, the frequency band in which noise propagation can be blocked shifts to the higher frequency side, as shown in graph E of FIG. 9(B). Here, we are trying to block the propagation of noise with a center frequency of f0. Therefore, even if the frequency band is shifted to the higher frequency side to the extent that it can be represented by graph E, the performance of blocking the propagation of noise with a center frequency of f0 is maintained. In other words, by forming the vias 14, the EBG structure can be miniaturized while maintaining the performance of blocking the propagation of noise with a center frequency of f0.

[0049] As an example, it has been confirmed that when the EBG structure shown in FIG. 6 and FIG. 7 is adopted, the area of ​​the EBG structure can be reduced by 20% or more.

[0050] Here, when arranging multiple unit circuits, the goal is to arrange completely identical unit circuits, but if the line width and length of stub 13 are within ±60% and ±15%, respectively, it is possible to achieve the objective of preventing the propagation of at least one noise with a common center frequency f0.

[0051] FIG. 10 is a plan view of the EBG structure according to various embodiments.

[0052] 10(A) shows an example of an EBG structure having a spiral-shaped conductor line. In this example, unconnected vias 14 are arranged in four locations (top, bottom, left, and right) for each unit circuit in the ground 11.

[0053] 10(B) shows another example of an EBG structure having a spiral-shaped conductor line. In this example, unconnected vias 14 are placed in two places, above and below, for each unit circuit in the ground 11.

[0054] As shown in these examples, there is no limit to the number of vias 14.

[0055] Fig. 10(C) shows an example of an EBG structure having a meandering stub 13. In Fig. 10(C), two vias 14 are formed on the top and bottom so that two unit circuits on the top and bottom are adjacent to each other.

[0056] Fig. 10(D) shows an example of an EBG structure having a linear stub 13. In Fig. 10(D), vias 14 are formed at two locations, the center position and the open end, for each unit circuit so that two upper and lower unit circuits are adjacent to each other.

[0057] As shown in these examples, the present invention is applicable regardless of the shape of the stub 13. [Explanation of symbols]

[0058] 10 Circuit Board 11 Grand 12 Via 13 Stub 14 Via

Claims

1. a plurality of discrete electronic circuits arranged in an array, each of the plurality of discrete electronic circuits comprising: a first conductor post extending in a stacking direction and connected to a ground of a first layer among a plurality of conductor layers stacked in sequence with a space between them; a conductor line that is connected to the first conductor pole in a second layer different from the first layer among the plurality of conductor layers, extends in a strip shape, and has an open end at an end away from the first conductor pole; a second conductor post extending in the lamination direction, the second conductor post being connected to the conductor line and not connected to ground; An electronic circuit characterized in that each of adjacent first and second individual electronic circuits among the plurality of individual electronic circuits has at least a pair of the second conductor columns formed in adjacent positions without sandwiching the conductor lines of either the first or second individual electronic circuit between them.

2. 2. The electronic circuit according to claim 1, wherein the plurality of individual electronic circuits are circuits for suppressing at least one electromagnetic noise of the same frequency.

3. 3. The electronic circuit according to claim 2, wherein the conductor line of each of the plurality of individual electronic circuits is a line in which an end portion other than the open end of the conductor line is connected to the first conductor column.

4. 4. The electronic circuit according to claim 3, wherein the conductor line is a line that extends while bending continuously or intermittently in the same rotational direction from one end to the other end.

5. A circuit board having the electronic circuit according to any one of claims 1 to 4 mounted thereon.

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