Multilayer substrates and high-frequency modules

Abstract

The present invention provides a multilayer substrate and a high-frequency module capable of suppressing parasitic capacitance caused by parallel plates in the first signal pad. [Solution] In a high-frequency module that vertically supplies high-frequency signals into a first high-frequency circuit board 1a by making surface contact between a signal spring terminal 41 surface-mounted on a second high-frequency circuit board 8 and a first signal pad 11 provided at a position opposite to the signal spring terminal 41 on the first high-frequency circuit board (multilayer board) 1a and connected to a signal via hole 3 inside the first high-frequency circuit board 1a, a ninth ground layer 29 and a tenth ground layer 210 are provided between the signal line 7 and the eleventh ground layer which is a solid ground, with openings provided such that, when viewed from the board stacking direction in plan view, they include at least a part of the first signal pad 11.

Description

Technical Field

[0001] The present invention relates to a multilayer substrate and a high-frequency module.

Background Art

[0002] Conventionally, there is a high-frequency module in which a first high-frequency circuit substrate (multilayer substrate) on which a plurality of high-frequency devices are surface-mounted, and a second high-frequency circuit substrate that supplies high-frequency signals to each high-frequency device on the first high-frequency circuit substrate are electrically connected. For example, in the high-frequency module disclosed in Patent Document 1, the first high-frequency circuit substrate and the second high-frequency circuit substrate are electrically connected by bringing a signal spring terminal surface-mounted on a second signal pad on the second high-frequency circuit substrate into surface contact with a first signal pad provided at a position on the end face of the first high-frequency circuit substrate opposite to the spring terminal, to transmit high-frequency signals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the high-frequency module disclosed in Patent Document 1, parasitic capacitance due to a parallel flat plate is generated between the first signal pad on the first high-frequency circuit substrate and the solid ground provided on the first high-frequency circuit substrate. Accordingly, there is a problem that characteristic impedance mismatch occurs at the first signal pad of the first high-frequency circuit substrate.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a first high-frequency circuit board (multilayer board) and a high-frequency module that can suppress parasitic capacitance caused by parallel plates between a first signal pad and a ground plane in a first high-frequency circuit board. [Means for solving the problem]

[0006] To achieve the above objective, the first high-frequency circuit board (multilayer board) of the present invention comprises a first dielectric layer, a first signal pad formed on one end face of the first dielectric layer, a first ground pad connected to ground and formed on one end face of the first dielectric layer at a predetermined distance from the first signal pad and surrounding the first signal pad, a seventh dielectric layer laminated on the other end face side of the first dielectric layer, a signal via hole extending in the substrate lamination direction through the first dielectric layer and overlapping with the first signal pad in a plan view from the substrate lamination direction, and the seventh dielectric layer close to the first dielectric layer. The substrate comprises: a signal line formed on one end face, which, when viewed from the substrate stacking direction, has one end electrically connected to a signal via hole; a seventh ground layer formed on the end face of the seventh dielectric layer close to the first dielectric layer, with a predetermined distance from the signal line; a tenth ground layer formed on the end face side of the seventh dielectric layer far from the first dielectric layer, which, when viewed from the substrate stacking direction, has an opening that includes at least a portion of the first signal pad; and a plurality of ground via holes that electrically connect each of the layers: the first ground pad, the seventh ground layer, and the tenth ground layer. Furthermore, the high-frequency module of the present invention includes a second high-frequency circuit board having a plurality of second signal pads and a plurality of second ground pads surrounding the second signal pads formed on the end face facing the first high-frequency circuit board (multilayer board). It also includes a plurality of signal spring terminals connected to the first signal pads and the second signal pads of the second high-frequency circuit board, respectively, for transmitting high-frequency signals between the first high-frequency circuit board and the second high-frequency circuit board. It also includes a plurality of ground spring terminals connected to the first ground pad of the first high-frequency circuit board and the second ground pad of the second high-frequency circuit board, respectively. [Effects of the Invention]

[0007] According to the present invention, parasitic capacitance occurring between the first signal pad and the ground plane in a multilayer substrate can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of a high-frequency module according to Embodiment 1. [Figure 2] This is a detailed view of A in Figure 1. [Figure 3] This is a cross-sectional view of section II in Figure 1. [Figure 4] This is a diagram showing the configuration of the first conductor layer, the first signal pad, and the first ground pad of the first high-frequency circuit board according to Embodiment 1. [Figure 5] This is a diagram showing the configuration of the second conductor layer of the first high-frequency circuit board according to Embodiment 1. [Figure 6] This is a diagram showing the configuration of the sixth conductor layer of the first high-frequency circuit board according to Embodiment 1. [Figure 7] This is a diagram showing the configuration of the seventh conductor layer of the first high-frequency circuit board according to Embodiment 1. [Figure 8] This is a diagram showing the configuration of the eighth conductor layer of the first high-frequency circuit board according to Embodiment 1. [Figure 9] This is a diagram showing the configuration of the ninth conductor layer of the first high-frequency circuit board according to Embodiment 1. [Figure 10] This is a configuration diagram of the 11th conductor layer of the first high-frequency circuit board according to the first embodiment. [Figure 11] This is a configuration diagram of the 12th conductor layer of the first high-frequency circuit board according to the first embodiment. [Figure 12] This is a cross-sectional view taken along the II-II cutting plane of Figure 1. [Figure 13] This is a cross-sectional view taken along the III-III cutting plane of Figure 1. [Figure 14] This is a configuration diagram of the 7th conductor layer of the first high-frequency circuit board according to the first modification of the first embodiment. [Figure 15] This is a configuration diagram of the first conductor layer, the first signal pad, and the first ground pad of the first high-frequency circuit board according to the second modification of the first embodiment. [Figure 16] This is a configuration diagram of the 7th conductor layer of the first high-frequency circuit board according to the second modification of the first embodiment. [Figure 17] This is a cross-sectional view of the first high-frequency circuit board according to the third modification of the first embodiment. [Figure 18] This is a cross-sectional view taken along the IV-IV cutting plane of Figure 17. [Figure 19] This is a cross-sectional view of the high-frequency module according to the second embodiment. [Figure 20] This is a detailed view of B in Figure 19. [Modes for Carrying Out the Invention]

[0009] The modes for carrying out the present invention will be described. Hereinafter, the same or corresponding components are denoted by the same reference numerals, and descriptions of these components will not be repeated. In each figure, X, Y, and Z indicate coordinate axes. The X-axis direction is the board stacking direction of the first high-frequency circuit board 1. The Y-axis direction is a direction intersecting the X-axis direction, strictly speaking, orthogonal to the X-axis direction. The Z-axis direction is a direction intersecting both the X-axis direction and the Y-axis direction, strictly speaking, a direction orthogonal to both the X-axis direction and the Y-axis direction. The plane direction parallel to the Y-axis direction and the Z-axis direction is the board plane direction.

[0010] Embodiment 1. The configuration of the high-frequency module 100 according to Embodiment 1 will be described using FIGS. 1 to 3. FIG. 1 is a cross-sectional view of the high-frequency module according to Embodiment 1. FIG. 2 is a detailed view of part A in FIG. 1. FIG. 3 is a cross-sectional view taken along the I-I cutting plane in FIG. 1.

[0011] As shown in FIG. 1, the high-frequency module 100 of Embodiment 1 is configured such that a first high-frequency circuit board 1 and a second high-frequency circuit board 8 are provided on a cooling plate 9.

[0012] A high-frequency device 5 is surface-mounted on one end face of the first high-frequency circuit board 1. Specifically, the high-frequency device refers to a phase shifter, a switch, a driver amplifier, an HPA, a circulator, a high-withstand-voltage switch, a low-noise amplifier, and the like.

[0013] The high-frequency device 5 surface-mounted on the first high-frequency circuit board 1 is electrically connected to a signal transmission line 10 formed inside the first high-frequency circuit board 1.

[0014] The first high-frequency circuit board 1 is mechanically and thermally connected to the cooling plate 9 at the end face opposite to the end face on which the high-frequency device 5 is mounted. A space for accommodating the second high-frequency circuit board 8, which will be described later, is formed between the first high-frequency circuit board 1 and the cooling plate 9.

[0015] The second high-frequency circuit board 8 is a high-frequency circuit board that supplies high-frequency signals to the high-frequency device 5 on the first high-frequency circuit board 1. The second high-frequency circuit board 8 is accommodated in the space formed between the first high-frequency circuit board 1 and the cooling plate 9. The second high-frequency circuit board 8 is mechanically and thermally connected to the cooling plate 9 at one end face. The other end face of the distribution circuit faces the end face of the first high-frequency circuit board 1 opposite to the end face on which the high-frequency device 5 is surface-mounted.

[0016] As shown in Figures 2 and 3, a first signal pad 11 and a first ground pad 21 surrounding the first signal pad 11 are formed on the end face of the first high-frequency circuit board 1 facing the second high-frequency circuit board 8. The first ground pad 21 is connected to ground. In other words, the first ground pad is grounded. A second signal pad 61 and a second ground pad 51 surrounding the second signal pad 61 are formed on the end face of the second high-frequency circuit board 8 facing the first high-frequency circuit board 1. The first signal pad 11 and the second signal pad 61 are formed in positions opposite to each other. The first ground pad 21 and the second ground pad 51 are formed in positions opposite to each other.

[0017] The high-frequency module 100 is located between the first high-frequency circuit board 1 and the second high-frequency circuit board 8 and includes signal spring terminals 41 connected to the first signal pad 11 and the second signal pad 61, respectively.

[0018] Furthermore, the high-frequency module 100 includes a plurality of ground spring terminals 42 connected to the first ground pad 21 and the second ground pad 51, respectively, between the first high-frequency circuit board 1 and the second high-frequency circuit board 8. The plurality of ground spring terminals 42 are provided surrounding the signal spring terminals 41.

[0019] For the sake of explanation, the signal spring terminal 41 and the ground spring terminal 42 may be collectively referred to as spring terminals. Also, the first signal pad 11 and the first ground pad 21 may be collectively referred to as the first pad, and the second signal pad 61 and the second ground pad 51 may be collectively referred to as the second pad.

[0020] The signal spring terminals 41 are surface-mounted to the second signal pad 61 by soldering. The multiple ground spring terminals 42 are surface-mounted to the second ground pad 51 by soldering. In other words, the spring terminals are surface-mounted to the second pad.

[0021] The first high-frequency circuit board 1 is fixed to the cooling plate 9, for example, with screws. When the screws used to fix the first high-frequency circuit board 1 to the cooling plate 9 are tightened into the cooling plate 9, the spring terminal sandwiched between the first high-frequency circuit board 1 and the second high-frequency circuit board 8 is compressed. As a result, the spring terminal makes firm surface contact with the first pad. High-frequency signals can be transmitted by the surface contact of the spring terminal with the first pad. Surface contact means that the contact area is not a point but has a certain area.

[0022] In this configuration, the multiple ground spring terminals 42 are connected to the ground by being electrically connected to the first ground pad 51. Since the multiple ground spring terminals 42 connected to the ground surround the signal spring terminal 41, a pseudo-coaxial line is formed. Therefore, when a signal is transmitted, leakage of signals to the outside can be suppressed.

[0023] A spring terminal is, for example, a metal plate spring formed into a Z shape. The dimensions of a Z-shaped spring terminal are, for example, that the flat surfaces at both ends are 1.5 mm on the short side and 1.7 mm on the long side, and the height from one end to the other is 1.0 mm.

[0024] The high-frequency device 5 is electrically connected to one end of a signal transmission line 10 located inside the first high-frequency circuit board 1. The first signal pad 11 is electrically connected to the other end of the signal transmission line 10. In other words, the high-frequency device 5 and the first signal pad 11 are electrically connected via the signal transmission line 10. Furthermore, the first signal pad 11 is electrically connected to the second signal pad 61 via a signal spring terminal 41. Therefore, the high-frequency signal output from the second high-frequency circuit board 8 is transmitted to the high-frequency device 5 via the second signal pad 61, the signal spring terminal 41, the first signal pad 11, and the signal transmission line 10.

[0025] Next, a first high-frequency circuit board 1 having the characteristic configuration of this disclosure will be described in detail with reference to Figures 2 to 14.

[0026] As shown in Figures 2 and 3, the first high-frequency circuit board 1 has a first dielectric layer 31, a second dielectric layer 32, a third dielectric layer 33, a fourth dielectric layer 34, a fifth dielectric layer 35, a sixth dielectric layer 36, a seventh dielectric layer 37, an eighth dielectric layer 38, a ninth dielectric layer 39, a tenth dielectric layer 310, and an eleventh dielectric layer 311.

[0027] Furthermore, the first high-frequency circuit board 1 has a first signal layer 11 (first signal pad 11), a second signal layer 12, a third signal layer 13, a fourth signal layer 14, a fifth signal layer 15, a sixth signal layer 16, and a seventh signal layer 17.

[0028] Furthermore, the first high-frequency circuit board 1 has a first ground layer 21 (first ground pad 21), a second ground layer 22, a third ground layer 23, a fourth ground layer 24, a fifth ground layer 25, a sixth ground layer 26, a seventh ground layer 27, an eighth ground layer 28, a ninth ground layer 29, a tenth ground layer 210, an eleventh ground layer 211, and a twelfth ground layer 212.

[0029] Furthermore, the first high-frequency circuit board 1 has a plurality of ground via holes 2, signal via holes 3, and signal lines 7.

[0030] The conductor layer containing the first signal pad 11 and the first ground pad 21 is called the first conductor layer. The conductor layer containing the second signal layer 12 and the second ground layer 22 is called the second conductor layer. The conductor layer containing the third signal layer 13 and the third ground layer 23 is called the third conductor layer. The conductor layer containing the fourth signal layer 14 and the fourth ground layer 24 is called the fourth conductor layer. The conductor layer containing the fifth signal layer 15 and the fifth ground layer 25 is called the fifth conductor layer. The conductor layer containing the sixth signal layer 16 and the sixth ground layer 26 is called the sixth conductor layer. The conductor layer containing the seventh signal layer 17, the seventh ground layer 27, and the signal line 7 is called the seventh conductor layer. The conductor layer containing the eighth ground layer 28 is called the eighth conductor layer. The conductor layer containing the ninth ground layer 29 is called the ninth conductor layer. The conductor layer containing the tenth ground layer 210 is called the tenth conductor layer. The conductor layer containing the 11th ground layer 211 is called the 11th conductor layer. The conductor layer containing the 12th ground layer 212 is called the 12th conductor layer.

[0031] The first high-frequency circuit board 1 is a multilayer substrate in which the first to twelfth conductor layers and the first to eleventh dielectric layers are stacked alternately.

[0032] Signal via hole 3 is a conductive hole whose inner surface is plated with a metal such as copper.

[0033] The second signal layer 12 to the seventh signal layer 17 are, for example, lands formed around the signal via hole 3. The second signal layer 12 to the seventh signal layer 17 are not necessarily required.

[0034] One end of the signal via hole 3 is connected to the first signal pad 11. The other end of the signal via hole 3 is connected to the seventh signal layer 17. If the seventh signal line 17 is not provided, the other end of the signal via hole 3 is connected to the signal line 7. The signal via hole 3 penetrates the first dielectric layer 31 to the sixth dielectric layer 36. The signal via hole 3 also penetrates the second signal layer 12 to the sixth signal layer 16. The signal via hole 3 is electrically connected to each of the second signal layer 12 to the sixth signal layer 16. In other words, the first signal pad 11, the second signal layer 12, the third signal layer 13, the fourth signal layer 14, the fifth signal layer 15, the sixth signal layer 16, and the seventh signal layer 17 are electrically connected to each other via the signal via hole 3.

[0035] Although it was explained that the first signal pad 11 and the seventh signal layer 17 are electrically connected by a single signal via hole 3 extending straight from the first signal pad 11 to the seventh signal layer 17, any configuration that electrically connects the first signal pad 11 and the seventh signal layer 17 is acceptable. The first signal pad 11 and the seventh signal layer 17 may be electrically connected by multiple signal via holes 3 extending between each layer of the seventh signal layer 17. In this case, the multiple signal via holes 3 may be offset to the extent that the electrical connection can be maintained when viewed from the direction of substrate stacking. Furthermore, the first signal pad 11 and the seventh signal layer 17 may be electrically connected by multiple signal via holes 3 extending straight from the first signal pad 11 to the seventh signal layer 17. In other words, it is sufficient that the first signal pad 11 and the seventh signal layer 17 are electrically connected by at least one signal via hole 3.

[0036] The signal via hole 3 and the signal line 7 constitute a part of the signal transmission line 10.

[0037] The multiple ground via holes 2 are multiple conductive holes whose inner surfaces are plated with a metal such as copper.

[0038] Multiple ground via holes: The via holes 2 penetrate each dielectric layer from the first dielectric layer 31 to the eleventh dielectric layer 311 and each ground layer from the second ground layer 22 to the eleventh ground layer 211, with one end connected to the first ground layer 21 and the other end connected to the twelfth ground layer 212.

[0039] Furthermore, the multiple ground via holes 2 penetrate each dielectric layer from the ninth dielectric layer 39 to the eleventh dielectric layer 311, and each ground layer of the tenth ground layer 210 and the eleventh ground layer 211, with one end connected to the ninth ground layer 29 and the other end connected to the twelfth ground layer 212.

[0040] Furthermore, the multiple ground via holes 2 penetrate each dielectric layer from the first dielectric layer 31 to the fourth dielectric layer 341 and each ground layer from the second ground layer 22 to the fourth ground layer 24, with one end connected to the first ground pad 21 and the other end connected to the fifth ground layer 25.

[0041] Furthermore, the multiple ground via holes 2 penetrate the 11th dielectric layer 311, with one end connected to the 11th ground layer 211 and the other end connected to the 12th ground layer 212.

[0042] Each ground layer from the first ground pad 21 to the twelfth ground layer 212 is connected to the ground via a plurality of ground via holes 2 and maintained at ground potential. In other words, each ground layer from the first ground pad to the twelfth ground layer 212 is grounded via a plurality of ground via holes 2.

[0043] Multiple Grand Beer Halls 2 surround the signal Beer Hall 3, the second signal layer 12 to the seventh signal layer 17, and the signal line 7.

[0044] The configuration of the multiple ground via holes 2 is not limited to the above-described configuration, as long as all ground layers from the first ground pad 21 to the twelfth ground layer 212 are electrically connected. For example, the first ground pad 21 to the twelfth ground layer 212 may be electrically connected by multiple ground via holes 2 extending between each ground layer from the first ground pad 21 to the twelfth ground layer 212.

[0045] In order to suppress the leakage of electromagnetic waves to the outside, it is desirable that the minimum distance between the multiple ground via holes 2 be such that it is 1 / 16 or less of the wavelength of the transmitted high-frequency signal.

[0046] Next, the first conductor layer will be described using Figures 2 and 4. Figure 4 is a configuration diagram of the first conductor layer, the first signal pad, and the first ground pad of the first high-frequency circuit board according to Embodiment 1.

[0047] As shown in Figure 2, a first signal pad 11 and a first ground pad 21 are formed on one end face of the first dielectric layer 31. The first signal pad 11 and the first ground pad 21 are located on the same plane.

[0048] As shown in Figure 4, the general shape of the first signal pad 11 is rectangular. The first signal pad 11 is formed with dimensions that allow it to maintain good characteristics, with a reflection loss of about 20 dB, even when the relative horizontal position of the first signal pad 11 and the signal spring terminal 41 is shifted by a certain amount from the design center. A certain amount can be exemplified as a horizontal shift of ±0.5 mm. Therefore, assuming that the flat surface of the signal spring terminal 41 is 1.5 mm on the short side and 1.7 mm on the long side, the flat surface of the first signal pad 11 should be 2.5 mm on the short side and 2.7 mm on the long side.

[0049] Although the general shape of the first signal pad 11 was exemplified as rectangular, it is not limited to this. For example, the general shape of the first signal pad 11 may be circular.

[0050] The first ground pad 21 is formed surrounding the first signal pad 11, with a predetermined distance between them. In other words, the first signal pad 11 is located inside the first opening (an opening provided in the first ground pad 21) provided in the first ground pad 21.

[0051] The general shape of the inner circumference of the first ground pad 21 is a rectangle with one corner rounded. In other words, the general shape of the first opening is a rectangle with one corner rounded. The predetermined distance between the first signal pad 11 and the first ground pad 21 is determined to match any general shape of the inner circumference of the first ground pad.

[0052] Although the general shape of the inner circumference of the first ground pad 21 was exemplified as a rectangle with one rounded corner, it is not limited to this. For example, it could be a rectangle with all rounded corners, or it could be a circle.

[0053] Next, the second conductor layer will be described using Figures 2 and 5. Figure 5 is a diagram showing the configuration of the second conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0054] As shown in Figure 2, the second dielectric layer 32 is laminated on the other end face side of the first dielectric layer 31. The other end face of the first dielectric layer is the end face of the first dielectric layer 31 on which the first signal pad 11 and the first ground pad 21 are formed, that is, the end face opposite to the end face on which the first conductor layer is formed.

[0055] A second signal layer 12 and a second ground layer 22 are formed between the first dielectric layer 31 and the second dielectric layer 32. In other words, a second conductor layer is formed between the first dielectric layer 31 and the second dielectric layer 32. The second ground layer 22 and the second signal layer 12 are located on the same plane.

[0056] As shown in Figure 5, the second ground layer 22 is formed surrounding the second signal layer 12, with a predetermined distance between them. If the second signal layer 12 is not provided, the second ground layer 22 is formed surrounding the signal via hole 3. In other words, the second signal layer 12 is located inside the second opening (the opening provided in the second ground layer 22) provided in the second ground layer 22.

[0057] The second signal layer 12 has a circular shape. When viewed from above in the direction of substrate stacking, the second signal layer overlaps with the first signal pad. The center point of the first signal pad 11 and the center point of the second signal layer 12 coincide. More precisely, the center point of the first signal pad 11 and the center point of the second signal layer 12 are identical.

[0058] The general shape of the inner circumference of the second ground layer 22 is a rectangle with one corner rounded. In other words, the general shape of the second opening is a rectangle with one corner rounded.

[0059] The general shape of the second opening in the second ground layer 22 is the same as the general shape of the first opening in the first ground pad 21. Also, the size of the second opening in the second ground layer 22 is the same as the size of the first opening in the first ground pad 21. In other words, the second opening in the second ground layer 22 coincides with the first opening in the first ground pad 21.

[0060] The predetermined distance between the second signal layer 12 and the second ground layer 22 is determined to match any general shape of the inner circumference of the second ground layer 22.

[0061] The configurations of the third, fourth, and fifth conductor layers are the same as those of the second conductor layer, so their explanation will be omitted. The correspondence between the configuration of the second conductor layer and the configurations of the third through fifth conductor layers is described below.

[0062] The third signal layer 13, the fourth signal layer 14, and the fifth signal layer 15 correspond to the second signal layer 12. The third ground layer 23, the fourth ground layer 24, and the fifth ground layer correspond to the second ground layer 22. The third dielectric layer corresponds to the second dielectric layer 32.

[0063] An opening provided in the third ground layer 23 is called the third opening. An opening provided in the fourth ground layer 24 is called the fourth opening. An opening provided in the fifth ground layer 25 is called the fifth opening.

[0064] The second ground layer 22 to the fifth ground layer 25 are electrically connected by a plurality of ground via holes 2 surrounding the signal via hole 3 and the second signal layer 12 to the fifth signal layer 15. In other words, the signal via hole 3, the second signal layer 12 to the fifth signal layer 15, and the second ground layer 21 to the fifth ground layer 25 form a pseudo-coaxial line for transmitting high-frequency signals between the first signal pad 11 and the signal line 7, which will be described later. This prevents leakage of high-frequency signals to the outside.

[0065] Furthermore, increasing the distance between signal via hole 3 and ground via hole 2, or the distance between the second signal layer 12 to the fifth signal layer 15 and the ground layer, increases the inductivity of the pseudo-coaxial line. Therefore, it is possible to adjust the characteristic impedance in the pseudo-coaxial line.

[0066] Furthermore, the second to fifth conductor layers can be increased or decreased in number.

[0067] Next, the sixth conductor layer will be described using Figures 2 and 6. Figure 6 is a diagram showing the configuration of the sixth conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0068] As shown in Figure 2, the sixth dielectric layer 36 is stacked on the side of the fifth dielectric layer 35 opposite to the first dielectric layer 31. The sixth signal layer 16 and the sixth ground layer 26 are formed between the fifth dielectric layer 35 and the sixth dielectric layer 36. In other words, the sixth conductor layer is formed between the fifth dielectric layer 35 and the sixth dielectric layer 36. The sixth signal layer 16 and the sixth ground layer 26 are located on the same plane.

[0069] As shown in Figure 6, the sixth ground layer 26 is formed surrounding the sixth signal layer 16 and the signal lines 7, with a predetermined distance between them, in a plan view from the substrate stacking direction. If the sixth signal layer 16 is not provided, it is formed with a predetermined distance between it and the signal via holes 3. In other words, the sixth signal layer 16 is formed inside the sixth opening (the opening provided in the sixth ground layer 26) provided in the sixth ground layer 26.

[0070] The sixth signal layer 16 has a circular shape. When viewed from above in the direction of substrate stacking, the sixth signal layer 16 overlaps with the first signal pad 11. The center point of the first signal pad 11 and the center point of the sixth signal layer 16 coincide. More precisely, the center point of the first signal pad 11 and the center point of the sixth signal layer 16 are identical. Furthermore, when viewed from above in the direction of substrate stacking, the sixth signal layer 16 coincides with the second signal layer 12 to the fifth signal layer 15.

[0071] The general shape of the sixth opening is a rectangle with one corner rounded.

[0072] The general shape of the sixth opening is the same as the general shape of the first to fifth openings. Also, the size of the sixth opening is the same as the size of the first to fifth openings. In other words, when viewed from the direction of substrate stacking, the sixth opening coincides with the first to fifth openings.

[0073] The predetermined distance between the first signal pad 11 and the sixth ground pad 26 is determined according to the arbitrary general shape of the inner circumference of the sixth ground layer 26, that is, the arbitrary general shape of the sixth opening.

[0074] Furthermore, the sixth ground layer 26 is formed at a predetermined distance from the signal line 7 when viewed from the substrate stacking direction. In other words, the signal line 7 is formed within the sixth slit when viewed from the substrate stacking direction.

[0075] Next, the seventh conductor layer will be described using Figures 2 and 7. Figure 7 is a diagram showing the configuration of the seventh conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0076] As shown in Figure 2, the seventh dielectric layer 37 is laminated on the opposite side of the sixth dielectric layer 36 from the first dielectric layer 31. The seventh signal layer 17, the signal line 7, and the seventh ground layer 27 are formed between the sixth dielectric layer 36 and the seventh dielectric layer 37. The seventh signal layer 17, the signal line 7, and the seventh ground layer 27 are located on the same plane.

[0077] As shown in Figure 7, the seventh signal layer 17 has a circular shape. When viewed from above in the direction of substrate stacking, the seventh signal layer 17 overlaps with the first signal pad 11. The center point of the first signal pad 11 and the center point of the seventh signal layer 17 coincide. More precisely, the center point of the first signal pad 11 and the center point of the seventh signal layer 17 are identical. Furthermore, when viewed from above in the direction of substrate stacking, the seventh signal layer 17 coincides with the second signal layer 12 to the sixth signal layer 16.

[0078] The signal line 7 is a linear copper foil for transmitting high-frequency signals. One end of the signal line 7 is connected to the seventh signal layer 17. That is, the signal line 7 is electrically connected to the signal via hole 3 via the seventh signal layer 17. Note that the signal line 7 only needs to be electrically connected to the signal via hole 3; if the seventh signal line 7 is not provided, it may be directly connected to the signal via hole 3. When viewed from the planar direction of the substrate stacking, one end of the signal line 7 overlaps with the first signal pad 11.

[0079] The seventh signal layer 17 and signal line 7 can be collectively referred to as the signal line.

[0080] The seventh ground layer 27 is formed surrounding the seventh signal layer 17, with a predetermined distance between them. In other words, the seventh signal layer 17 is formed inside the seventh opening (an opening provided in the seventh ground layer 27) in the seventh ground layer 27. If the seventh signal layer 17 is not provided, it can be formed with a predetermined distance between it and the signal via hole 3.

[0081] The general shape of the seventh opening in the seventh ground layer 27 is a rectangle with one corner rounded.

[0082] The general shape of the seventh opening in the seventh ground layer 27 is the same as the general shape of the first to sixth openings. Also, the size of the seventh opening is the same as the size of the first to sixth openings. In other words, when viewed from the substrate stacking direction in plan view, the seventh opening coincides with the first to sixth openings.

[0083] Furthermore, the seventh ground layer 27 is formed at a predetermined distance from the signal line 7. In other words, the signal line 7 is formed within the second slit portion (the slit portion provided in the seventh ground layer 27) provided in the seventh ground layer 27.

[0084] The second slit portion coincides with the first slit portion when viewed from the direction of substrate stacking.

[0085] Next, the eighth conductor layer will be described using Figures 2 and 8. Figure 8 is a diagram showing the configuration of the eighth conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0086] The eighth dielectric layer 38 is laminated on the side of the seventh dielectric layer 37 opposite to the first dielectric layer 31. An eighth ground layer 28 is formed between the eighth dielectric layer 38 and the eighth dielectric layer 38.

[0087] The eighth ground layer 28 is formed at a predetermined distance from the seventh signal layer 17 when viewed from the substrate stacking direction. In other words, when viewed from the substrate stacking direction, the seventh signal layer 17 is formed inside the eighth opening (an opening provided in the eighth ground layer 28) provided in the eighth ground layer 28. If the seventh signal layer 17 is not provided, it is formed at a predetermined distance from the signal via hole 3 when viewed from the substrate stacking direction.

[0088] Furthermore, the eighth ground layer 28 is formed at a predetermined distance from the signal line 7 when viewed from the substrate stacking direction. In other words, when viewed from the substrate stacking direction, the signal line 7 is formed within the third slit portion (the slit portion provided in the eighth ground layer 27) provided in the eighth ground layer 28.

[0089] The third slit portion coincides with the first and second slit portions when viewed from the substrate stacking direction.

[0090] In Embodiments 1 and 2, the sixth ground layer 26 and the eighth ground layer 28 are not necessarily required, but by providing them, the distance between the signal line 7 and the ground layer in the substrate stacking direction can be reduced. This increases the capacitance of the signal line 7, which has the effect of forming a low-impedance transmission line.

[0091] Next, the ninth conductor layer will be described using Figures 2 and 9. Figure 9 is a diagram showing the configuration of the ninth conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0092] As shown in Figure 2, the ninth dielectric layer 39 is laminated on the side of the eighth dielectric layer 38 opposite to the first dielectric layer 31. A ninth ground layer 29 is formed between the eighth dielectric layer 38 and the ninth dielectric layer 39.

[0093] As shown in Figure 9, the ninth ground layer 29 is provided surrounding the first signal pad 11, with a predetermined distance between them, when viewed from the substrate stacking direction. In other words, when viewed from the substrate stacking direction, the first signal pad 11 is formed inside the ninth opening (the opening provided in the ninth ground layer 29) provided in the ninth ground layer 29. When viewed from the substrate stacking direction, the ninth opening overlaps with each of the openings from the first to the eighth. The general shape of the ninth opening is a rectangle with one rounded corner. The general shape of the ninth opening is the same as the general shape of each of the openings from the first to the eighth. Also, the size of the ninth opening is the same as the size of each of the openings from the first to the eighth. That is, when viewed from the substrate stacking direction, the ninth opening coincides with each of the openings from the first to the eighth.

[0094] Because a ninth ground layer 29 having a ninth opening is provided, the distance between the signal line 7 and the ground layer in the region overlapping with the ninth opening when viewed from the substrate stacking direction is greater than the distance between the signal line 7 and the ninth ground layer 29 in the region overlapping with the ninth ground layer 29 when viewed from the substrate stacking direction.

[0095] The ninth opening may be provided such that, when viewed from the substrate direction in a plan view, it includes at least a portion of the first signal pad 11.

[0096] The configuration of the 10th conductor layer is the same as that of the 9th conductor layer, so its explanation will be omitted. The correspondence between the configuration of the 9th conductor layer and the configuration of the 10th conductor layer is described below.

[0097] The tenth ground layer 210 corresponds to the ninth ground layer 29. The tenth dielectric layer 310 corresponds to the ninth dielectric layer 39.

[0098] The tenth opening is an opening provided in the tenth ground layer 210.

[0099] By providing a ninth ground layer 29 having a ninth opening and a tenth ground layer 210 having a tenth opening, the distance between the first signal pad 11 and the eleventh ground layer 211, which is a solid ground, can be increased. This makes it possible to suppress parasitic capacitance caused by parallel plates between the first signal pad 11 and the eleventh ground layer 211.

[0100] Next, the 11th conductor layer will be described using Figures 2 and 10. Figure 10 is a diagram showing the configuration of the 11th conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0101] As shown in Figure 2, the 11th dielectric layer 311 is laminated on the opposite side of the 10th dielectric layer 310 from the first dielectric layer 31. An 11th ground layer 211 is formed between the 10th dielectric layer 310 and the 11th dielectric layer 311.

[0102] As shown in Figure 10, the 11th ground layer 211 is a solid ground with a ground pattern formed on one surface. That is, when viewed from the substrate stacking direction, the 11th ground layer 211 includes the regions of each of the openings from the first to the tenth opening. In other words, the 12th ground layer 212 is formed extending in the substrate plane direction and covers the first to the tenth opening. Therefore, it is possible to prevent high-frequency signals from leaking to the outside.

[0103] Next, the configuration of the 12th dielectric layer and the 12th ground layer 212 will be described in detail with reference to Figures 2 and 11. Figure 11 is a diagram showing the configuration of the 12th conductor layer of the first high-frequency circuit board according to Embodiment 1.

[0104] As shown in Figure 2, the 12th dielectric layer is laminated on the opposite side of the 11th dielectric layer 311 from the first dielectric layer 31. A 12th ground layer 212 is formed between the 11th dielectric layer 311 and the 12th dielectric layer.

[0105] As shown in Figure 11, the 12th ground layer 212 is a solid ground with a ground pattern formed on one surface. That is, when viewed from the substrate stacking direction, the 12th ground layer 212 includes the first to the 10th openings. In other words, the 12th ground layer 212 is formed extending in the planar direction of the substrate and covers the first to the 10th openings. Therefore, it is possible to prevent high-frequency signals from leaking to the outside.

[0106] The 11th ground layer 211 and the 12th ground layer 212 are shielding sections that prevent high-frequency signals from leaking out from the first opening to the 10th ground layer 210.

[0107] Next, the configuration of signal line 7 will be described in detail using Figures 12 and 13. Figure 12 is a cross-sectional view taken along line II-II in Figure 1. Figure 13 is a cross-sectional view taken along line III-III in Figure 1.

[0108] The signal line 7 has different signal transmission line configurations in the portion located within the second slit and the portion located within the seventh opening of the seventh ground layer. The signal transmission line consisting of the signal line 7 located within the seventh opening is called the first strip line, and the signal transmission line consisting of the signal line 7 located within the second slit is called the second strip line.

[0109] As shown in Figure 12, the signal line 7 in the first strip line is shielded by the 11th ground layer 211 on one side in the substrate stacking direction. In addition, the inner layer signal line 7 in the second strip line is shielded by multiple ground layers and multiple ground via holes on both sides in the line width direction (Y-axis direction).

[0110] As shown in Figure 13, the inner layer signal lines 7 in the second strip line are shielded on both sides in the substrate stacking direction by the fifth ground layer 25 and the ninth ground layer 29. In addition, the signal lines 7 in the first strip line are shielded on both sides in the line width direction (Y-axis direction) by the sixth ground layer 26 to the eighth ground layer 28 and a number of ground via holes.

[0111] Since the second strip line has a ninth and a tenth opening in the substrate stacking direction, the ninth ground layer 29 and the tenth ground layer 210 do not exist in the substrate stacking direction. Therefore, the distance between the signal line 7 and the ground layer in the second strip line in the substrate stacking direction is greater than the distance between the signal line 7 and the ground layer in the substrate stacking direction in the first strip line. As a result, the characteristic impedance of the signal line 7 in the second strip line is greater than the characteristic impedance of the signal line 7 in the first strip line. Therefore, the sixth, seventh, and eighth openings are designed so that the sixth, seventh, and ninth ground layers pass as close as possible to the seventh signal layer 17, thereby making the first strip line as long as possible. When the general shape of the sixth, seventh, and eighth openings is rectangular, the corners closest to the signal line 7 are rounded so that the sixth, seventh, and ninth ground layers pass as close as possible to the seventh signal layer 17.

[0112] As described above, the first high-frequency circuit board 1 of Embodiment 1 comprises a first dielectric layer, a first signal pad formed on one end face of the first dielectric layer, a first ground pad connected to ground and formed on one end face of the first dielectric layer at a predetermined distance from the first signal pad and surrounding the first signal pad, a seventh dielectric layer laminated on the other end face side of the first dielectric layer, a signal via hole extending through the first dielectric layer in the substrate lamination direction and overlapping with the first signal pad in a plan view from the substrate lamination direction, and a signal via hole formed on the end face of the seventh dielectric layer close to the first dielectric layer, with one end when viewed in a plan view from the substrate lamination direction By providing a signal line electrically connected to the signal via hole, a seventh ground layer formed on the end face of the seventh dielectric layer near the first dielectric layer and spaced apart from the signal line, a tenth ground layer formed on the end face of the seventh dielectric layer far from the first dielectric layer and having an opening that includes at least a portion of the first signal pad when viewed in plan from the substrate stacking direction, and a plurality of ground via holes electrically connecting each of the first ground pad, the seventh ground layer, and the tenth ground layer, parasitic capacitance between the high-frequency connector pad and the ground plane can be suppressed.

[0113] A modified example of Embodiment 1. The high-frequency module of Embodiment 1 may also adopt the following modified forms. Note that the following modifications can also be applied to high-frequency modules of other embodiments.

[0114] Modification 1 of Embodiment 1. Figure 14 is a diagram showing the configuration of the seventh conductor layer of a first high-frequency circuit board according to a modification 1 of Embodiment 1. As shown in Figure 14, the width of the slit portion may be made narrower. As the line width of the slit portion is widened and the distance between the signal line 7 and the ground layer in the planar direction of the substrate (Y-axis direction) increases, the influence of the distance to the ground layer in the substrate stacking direction on the characteristic impedance of the signal line 7 increases. Conversely, as the line width of the slit portion is narrowed and the distance between the signal line 7 and the ground layer in the planar direction of the substrate (Y-axis direction) decreases, the influence of the distance to the ground layer in the planar direction on the characteristic impedance of the signal line 7 increases.

[0115] Modification 2 of Embodiment 1. Figure 15 is a diagram showing the configuration of the first conductor layer, the first signal pad, and the first ground pad of the first high-frequency circuit board according to a modified example 2 of Embodiment 1. Figure 16 is a diagram showing the configuration of the seventh conductor layer of the first high-frequency circuit board according to a modified example 2 of Embodiment 1.

[0116] As shown in Figure 15, the general shape of the first signal pad 11 may be a rectangle with all corners rounded. Furthermore, the general shape of the first signal pad 11 may also be, for example, circular. The general shape of the first signal pad 11 may be arbitrarily modified without departing from the present invention.

[0117] Furthermore, the general shape of the first opening may be a rectangle with all corners rounded. In this case, the rounded corners positioned to overlap with the signal line 7 when viewed from the substrate stacking direction may have a lower curvature than the other rounded corners. In other words, the first opening may be provided such that, when viewed from the substrate stacking direction, the distance between the first ground pad 21 and the first signal pad at the position overlapping with the signal line 7 is smaller than the distance between the first ground pad 21 and the first signal pad at positions other than the position overlapping with the signal line 7.

[0118] Furthermore, as shown in Figure 16, in the seventh ground layer 27, where the second slit portion is provided at the position where the signal line 7 is arranged, the general shape of the seventh opening, excluding the second slit portion, may be rectangular with all corners rounded, similar to the first ground pad 21. Although the first ground pad 21 and the seventh ground pad 27 have been shown as examples, the general shape of the openings of the second ground layers 22 to the tenth ground layers 210, other than the first ground pad 21 and the seventh ground pad 27, may also be rectangular with all corners rounded. In addition, the general shape of the openings may be arbitrarily changed in addition to those shown in the figures, without departing from the present invention.

[0119] Modification 3 of Embodiment 1. Figure 17 is a cross-sectional view of the first high-frequency circuit board according to Modification 3 of Embodiment 1. Figure 18 is a cross-sectional view of the IV-IV cross-section in Figure 17. As shown in Figures 17 and 18, in the first high-frequency circuit board of the high-frequency module according to Modification 3 of Embodiment 1, when viewed from the substrate stacking direction, the distance between the eighth ground layer 28, the ninth ground layer 29, and the tenth ground layer 210 and the seventh signal layer gradually decreases as the ground layers move further away from the first signal pad 11. That is, the area of ​​the eighth, ninth, and tenth openings gradually decreases as the distance from the seventh signal layer increases. In other words, when viewed from the substrate stacking direction, the ninth opening is smaller in size than the eighth opening and the ninth opening is included in the eighth opening. Also, when viewed from the substrate stacking direction, the tenth opening is smaller in size than the ninth opening and the tenth opening is included in the ninth opening. As a result, the distance between the seventh signal layer 17 and the eighth ground layer 28 to the tenth ground layer changes gradually, thus suppressing abrupt changes in the characteristic impedance of the seventh signal layer 17.

[0120] If the seventh signal layer 17 is not provided, the distance between the eighth ground layer 28, the ninth ground layer 29, and the tenth ground layer 210 and the signal via hole 3 gradually decreases as the ground layer moves further away from the first signal pad 11.

[0121] Embodiment 2. The high-frequency module 200 according to Embodiment 2 will be described below with reference to Figures 19 and 20. Figure 19 is a cross-sectional view of the high-frequency module 200 according to Embodiment 2. Figure 20 is a detailed view of B in Figure 19. Components identical or equivalent to those described in Embodiment 1 are denoted by the same reference numerals, and redundant explanations are omitted. The difference between the first high-frequency circuit board 1a of Embodiment 1 and the first high-frequency circuit board 1b of Embodiment 2 is that in the first high-frequency circuit board 1a of Embodiment 1, the 11th ground layer 211a and the 12th ground layer 212a were solid grounds, whereas in the first high-frequency circuit board 1b of the high-frequency module 200, openings are provided in the 11th ground layer 211b and the 12th ground layer 212b. The first high-frequency circuit board 1b does not have a solid ground as a shielding portion, but instead has a shield cover 71.

[0122] In the first high-frequency circuit board 1b of Embodiment 2, since no openings are provided in the 11th ground layer 211b and the 12th ground layer 212b, parasitic capacitance of the first signal pad 11 caused by the parallel plates does not occur, making it easier to suppress parasitic capacitance than in Embodiment 1.

[0123] As shown in Figure 20, in the first high-frequency circuit board 1b of Embodiment 2, the eleventh ground layer 211b is provided surrounding the first signal pad 11 at a predetermined distance from the first signal pad 11 when viewed from the board stacking direction. In other words, when viewed from the board stacking direction, the first signal pad 11 is formed inside the eleventh opening (an opening provided in the eleventh ground layer 21) provided in the eleventh ground layer 211b. When viewed from the board stacking direction, the eleventh opening overlaps with the first to tenth openings. The general shape of the eleventh opening is a rectangle with one rounded corner. The general shape of the eleventh opening is the same as the general shape of the first to tenth openings. Also, the size of the eleventh opening is the same as the size of the first to tenth openings. In other words, when viewed from the direction of substrate stacking, the 11th opening coincides with the 1st to 10th openings.

[0124] The 11th ground layer 211b may be provided to include at least a portion of the first signal pad 11.

[0125] Furthermore, as shown in Figure 20, in the first high-frequency circuit board 1b according to Embodiment 2, the 12th ground layer 212b is provided surrounding the first signal pad 11 with a predetermined distance from it when viewed from the board stacking direction. In other words, when viewed from the board stacking direction, the first signal pad 11 is formed inside the 12th opening (opening provided in the 12th ground layer) provided in the 12th ground layer 212b. When viewed from the board stacking direction, the 12th opening overlaps with the first to 11th openings. The general shape of the 12th opening is a rectangle with one rounded corner. The general shape of the 12th opening is the same as the general shape of the first to 11th openings. Also, the size of the 12th opening is the same as the size of the first to 11th openings. In other words, when viewed from the direction of substrate stacking, the 12th opening coincides with the 1st to 11th openings.

[0126] Because a 12th ground layer 212 having a 12th opening is provided, there is no ground layer above the signal line 7 in the region that overlaps with the 12th opening when viewed from the substrate stacking direction.

[0127] The 12th ground layer 212b may be provided to include at least a portion of the first signal pad 11.

[0128] Furthermore, as shown in Figures 19 and 20, the first high-frequency circuit board 1b of Embodiment 2 has a shield cover 71 covering the first to 12th openings on the side of the 12th ground layer 212b opposite to the first dielectric layer. The shield cover 71 is electrically connected to the ground via hole and is connected to ground. Therefore, the shield cover 71 can suppress signal leakage to the outside from the first to 12th openings.

[0129] As described above, the first high-frequency circuit board of Embodiment 2 has openings in the 11th and 12th ground layers and does not have a solid ground plane, making it easier to suppress parasitic capacitance than the first high-frequency circuit board of Embodiment 1. Furthermore, by providing a shielding cover that is electrically connected to the ground via hole and covers the 9th ground opening, electromagnetic wave leakage can be suppressed.

[0130] In Embodiments 1 and 2, the spring terminal may be surface-mounted on the first pad of the first high-frequency circuit board, and the spring terminal may be in surface contact with the second pad of the second high-frequency circuit board. However, in that case, it is desirable that the second high-frequency circuit board 8 has the features of the present invention.

[0131] In Embodiments 1 and 2, the first to tenth openings do not necessarily need to coincide when viewed from the substrate stacking direction, and the impedance can be adjusted by changing the size and shape of each ground opening without departing from the present invention.

[0132] In Embodiments 1 and 2, the second to seventh signal layers 17 do not necessarily need to coincide when viewed from the substrate stacking direction. Also, the center points of the first to seventh signal layers 17 do not necessarily need to coincide when viewed from the substrate stacking direction. Within the scope of the present invention, the impedance can also be adjusted by changing the size, shape, and position of each signal layer.

[0133] In Embodiments 1 and 2, there is one signal via hole, but any number may be provided.

[0134] Although this disclosure describes only the first high-frequency circuit board 1, the second high-frequency circuit board 8 may have the same configuration as the first high-frequency circuit board 1.

[0135] The configurations shown in Embodiments 1 to 3 above are merely examples of the content of this disclosure, and it is possible to freely combine multiple embodiments. It is also possible to combine them with other known technologies. Furthermore, it is possible to omit or modify parts of the configuration without departing from the gist of this disclosure.

[0136] The various forms of this disclosure are summarized below as an appendix.

[0137] (Note 1) The first dielectric layer and A first signal pad formed on one end face of the first dielectric layer, A first ground pad is formed on one end face of the first dielectric layer, with a predetermined distance from the first signal pad, and surrounding the first signal pad, and is connected to the ground. A seventh dielectric layer is laminated on the other end face side of the first dielectric layer, A signal via hole extending through the first dielectric layer in the substrate stacking direction and overlapping the first signal pad in a plan view from the substrate stacking direction, A signal line is formed on the end face of the seventh dielectric layer that is close to the first dielectric layer, and when viewed in plan from the substrate stacking direction, one end of which is electrically connected to the signal via hole, A seventh ground layer is formed on the end face of the seventh dielectric layer that is close to the first dielectric layer, and is formed at a predetermined distance from the signal line, A tenth ground layer is formed on the side of the seventh dielectric layer that is farther from the first dielectric layer, and has an opening that includes at least a portion of the first signal pad when viewed in plan from the substrate stacking direction, A multilayer substrate comprising a plurality of ground via holes that electrically connect each of the layers, the first ground pad, the seventh ground layer, and the tenth ground layer. (Note 2) A second dielectric layer is laminated between the first dielectric layer and the seventh ground layer, The present invention further comprises a second ground layer formed between the first dielectric layer and the second dielectric layer, and when viewed in plan from the substrate stacking direction, a second ground layer formed at a predetermined distance from the signal via hole and surrounding the signal via hole, The multilayer substrate according to Appendix 1, characterized in that the plurality of ground via holes electrically connect the first ground pad, the second ground layer, the seventh ground layer, and the tenth ground layer. (Note 3) A sixth dielectric layer is laminated between the first dielectric layer and the seventh ground layer, A sixth ground layer is formed between the first dielectric layer and the sixth dielectric layer, and when viewed in plan from the substrate stacking direction, it is formed at a predetermined distance from the signal line, An eighth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises an eighth ground layer formed between the seventh dielectric layer and the eighth dielectric layer, with a predetermined distance from the signal line when viewed in plan from the substrate stacking direction, The multilayer substrate according to Appendix 1 or Appendix 2, characterized in that the plurality of ground via holes electrically connect the first ground pad, the sixth ground layer, the seventh ground layer, the eighth ground layer, and the tenth ground layer. (Note 4) A sixth dielectric layer is laminated between the second dielectric layer and the seventh ground layer, A sixth ground layer is formed between the second dielectric layer and the sixth dielectric layer, and when viewed in plan from the substrate stacking direction, it is formed at a predetermined distance from the signal line, An eighth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises an eighth ground layer formed between the seventh dielectric layer and the eighth dielectric layer, with a predetermined distance from the signal line when viewed in plan from the substrate stacking direction, The multilayer substrate according to Appendix 3, characterized in that the plurality of ground via holes electrically connect the first ground pad, the second ground layer, the sixth ground layer, the seventh ground layer, the eighth ground layer, and the tenth ground layer. (Note 5) A ninth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises a ninth ground layer formed between the seventh dielectric layer and the ninth dielectric layer, the ninth ground layer having an opening that includes at least a portion of the first signal pad, The multilayer substrate according to any one of the appendices 1 to 4, characterized in that the plurality of ground via holes electrically connect the first ground pad, the seventh ground layer, the ninth ground layer, and the tenth ground layer. (Note 6) A ninth dielectric layer is laminated between the eighth dielectric layer and the tenth ground layer, The present invention further comprises a ninth ground layer formed between the eighth dielectric layer and the ninth dielectric layer, and having an opening that, when viewed in plan from the substrate stacking direction, includes at least a portion of the first signal pad, The multilayer substrate according to Appendix 3 or Appendix 4, characterized in that the plurality of ground via holes electrically connect the first ground pad, the sixth ground layer, the seventh ground layer, the eighth ground layer, the ninth ground layer, and the tenth ground layer. (Note 7) An eleventh dielectric layer is laminated on the opposite side of the seventh dielectric layer from the tenth ground layer, The present invention further comprises a 12th ground layer, which is a solid ground formed on the end face side of the 11th dielectric layer that is further away from the first dielectric layer, The multilayer substrate according to any one of the appendices 1 to 6, characterized in that the plurality of ground via holes electrically connect the first ground pad, the seventh ground layer, the ninth ground layer, and the twelfth ground layer. (Note 8) A multilayer substrate according to any one of the appendices 1 to 6, further comprising a cover on the side of the 10th ground layer opposite to the first dielectric layer, which is electrically connected to the ground via hole and covers an opening provided in the 10th ground layer. (Note 9) The seventh dielectric layer further comprises a seventh signal layer formed on the end face of the seventh dielectric layer that is close to the first dielectric layer and overlaps with the signal via hole in a plan view from the substrate stacking direction, The multilayer substrate according to any one of the appendices 1 to 8, characterized in that the signal line is electrically connected to the signal via hole via the seventh signal layer. (Note 10) The multilayer substrate according to Appendix 9, characterized in that the seventh ground layer is formed to surround the signal lines in a rectangular shape, except for the position where it overlaps with the signal lines. (Note 11) The multilayer substrate according to Appendix 5 or Appendix 6, characterized in that the openings provided in the 10th ground layer are all included in the openings provided in the 9th ground layer when viewed in plan from the substrate stacking direction. (Note 12) A second high-frequency circuit board having a plurality of second signal pads formed on the end face facing the multilayer substrate described in Appendix 1, and a plurality of second ground pads surrounding the second signal pads, A signal spring terminal connected to the first signal pad and the second signal pad described in Appendix 1, respectively, for transmitting high-frequency signals between the multilayer board described in Appendix 1 and the second high-frequency circuit board, A high-frequency module comprising a plurality of ground spring terminals connected to the first ground pad and the second ground pad described in Appendix 1, respectively. [Explanation of Symbols]

[0138] 100 High-frequency module, 9 Cooling plate, 1a, 1b First high-frequency circuit board, 8 Second high-frequency circuit board, 5 High-frequency device, 2 Ground via hole, 3 Signal via hole, 6 Solder layer, 7 Signal line, 8 Second high-frequency circuit board, 10 Signal transmission line, 11 First signal pad (first signal layer), 12 Second signal layer, 13 Third signal layer, 14 Fourth signal layer, 15 Fifth signal layer, 16 Sixth signal layer, 17 Seventh signal layer, 21 First ground pad (first ground layer), 22 Second ground layer, 23 Third ground layer, 24 Fourth ground layer, 25 Fifth ground layer, 26 Sixth ground layer, 27 Seventh ground layer, 28 Eighth ground layer, 29 Ninth ground layer, 210 Tenth ground layer, 211a, 211b 11th ground layer, 212a, 212b 12th ground layer, 31 1st dielectric layer, 32 2nd dielectric layer, 33 3rd dielectric layer, 34 4th dielectric layer, 35 5th dielectric layer, 36 6th dielectric layer, 37 7th dielectric layer, 38 8th dielectric layer, 39 9th dielectric layer, 310 10th dielectric layer, 311 11th dielectric layer, 41 Signal spring terminal, 42 Ground spring terminal, 51 2nd ground pad, 61 2nd signal pad, 71 Shield cover

Claims

1. The first dielectric layer, A first signal pad formed on one end face of the first dielectric layer, A first ground pad is formed on one end face of the first dielectric layer, with a predetermined distance from the first signal pad, surrounding the first signal pad, and connected to the ground. A seventh dielectric layer is laminated on the other end face side of the first dielectric layer, A signal via hole extending through the first dielectric layer in the substrate stacking direction and overlapping the first signal pad in a plan view from the substrate stacking direction, A signal line is formed on the end face of the seventh dielectric layer that is close to the first dielectric layer, and when viewed in plan from the substrate stacking direction, one end of which is electrically connected to the signal via hole, A seventh ground layer is formed on the end face of the seventh dielectric layer that is close to the first dielectric layer, and is formed at a predetermined distance from the signal line, A tenth ground layer is formed on the side of the seventh dielectric layer that is farther from the first dielectric layer, and has an opening that includes at least a portion of the first signal pad when viewed in plan from the substrate stacking direction, A multilayer substrate comprising a plurality of ground via holes that electrically connect each of the layers, the first ground pad, the seventh ground layer, and the tenth ground layer.

2. A second dielectric layer is laminated between the first dielectric layer and the seventh ground layer, The present invention further comprises a second ground layer formed between the first dielectric layer and the second dielectric layer, and when viewed in plan from the substrate stacking direction, a second ground layer formed with a predetermined distance from the signal via hole and surrounding the signal via hole, The multilayer substrate according to claim 1, characterized in that the plurality of ground via holes electrically connect the first ground pad, the second ground layer, the seventh ground layer, and the tenth ground layer.

3. A sixth dielectric layer is laminated between the first dielectric layer and the seventh ground layer, A sixth ground layer is formed between the first dielectric layer and the sixth dielectric layer, and when viewed in plan from the substrate stacking direction, it is formed at a predetermined distance from the signal line, An eighth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises an eighth ground layer formed between the seventh dielectric layer and the eighth dielectric layer, with a predetermined distance from the signal line when viewed in plan from the substrate stacking direction, The multilayer substrate according to claim 1, characterized in that the plurality of ground via holes electrically connect the first ground pad, the sixth ground layer, the seventh ground layer, the eighth ground layer, and the tenth ground layer.

4. A sixth dielectric layer is laminated between the second dielectric layer and the seventh ground layer, A sixth ground layer is formed between the second dielectric layer and the sixth dielectric layer, and when viewed in plan from the substrate stacking direction, it is formed at a predetermined distance from the signal line, An eighth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises an eighth ground layer formed between the seventh dielectric layer and the eighth dielectric layer, with a predetermined distance from the signal line when viewed in plan from the substrate stacking direction, The multilayer substrate according to claim 2, characterized in that the plurality of ground via holes electrically connect the first ground pad, the second ground layer, the sixth ground layer, the seventh ground layer, the eighth ground layer, and the tenth ground layer.

5. A ninth dielectric layer is laminated between the seventh dielectric layer and the tenth ground layer, The present invention further comprises a ninth ground layer formed between the seventh dielectric layer and the ninth dielectric layer, the ninth ground layer having an opening that includes at least a portion of the first signal pad, The multilayer substrate according to claim 1 or 2, characterized in that the plurality of ground via holes electrically connect the first ground pad, the seventh ground layer, the ninth ground layer, and the tenth ground layer.

6. A ninth dielectric layer is laminated between the eighth dielectric layer and the tenth ground layer, The present invention further comprises a ninth ground layer formed between the eighth dielectric layer and the ninth dielectric layer, and having an opening that, when viewed in plan from the substrate stacking direction, includes at least a portion of the first signal pad, The multilayer substrate according to claim 3 or 4, characterized in that the plurality of ground via holes electrically connect the first ground pad, the sixth ground layer, the seventh ground layer, the eighth ground layer, the ninth ground layer, and the tenth ground layer.

7. An eleventh dielectric layer is laminated on the opposite side of the seventh dielectric layer from the tenth ground layer, The present invention further comprises a 12th ground layer, which is a solid ground formed on the end face side of the 11th dielectric layer that is further away from the first dielectric layer, The multilayer substrate according to claim 5, characterized in that the plurality of ground via holes electrically connect the first ground pad, the seventh ground layer, the ninth ground layer, and the twelfth ground layer.

8. A multilayer substrate according to any one of claims 1 to 4, further comprising a cover on the side of the 10th ground layer opposite to the first dielectric layer, which is electrically connected to the ground via hole and covers an opening provided in the 10th ground layer.

9. The seventh dielectric layer further comprises a seventh signal layer formed on the end face of the seventh dielectric layer that is close to the first dielectric layer and overlaps with the signal via hole in a plan view from the substrate stacking direction, The multilayer substrate according to any one of claims 1 to 4, characterized in that the signal line is electrically connected to the signal via hole via the seventh signal layer.

10. The multilayer substrate according to claim 9, characterized in that the seventh ground layer is formed to surround the signal lines in a rectangular shape, except for the position where it overlaps with the signal lines.

11. The multilayer substrate according to claim 5, characterized in that the openings provided in the tenth ground layer are all included in the openings provided in the ninth ground layer when viewed in plan from the substrate stacking direction.

12. A second high-frequency circuit board having a plurality of second signal pads and a plurality of second ground pads surrounding the second signal pads formed on an end face facing the multilayer substrate described in claim 1, A signal spring terminal connected to the first signal pad and the second signal pad described in claim 1, respectively, for transmitting a high-frequency signal between the multilayer substrate described in claim 1 and the second high-frequency circuit board, A high-frequency module comprising a plurality of ground spring terminals connected to the first ground pad and the second ground pad as described in claim 1.

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