JP2010129616A - Circuit board for high-frequency signal transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board for high-frequency signal transmission capable of suppressing mismatching of impedance caused between a transmission line and a pad region. <P>SOLUTION: The circuit board for high-frequency signal transmission includes a surface conductor layer where a transmission line 101 for high-frequency signal transmission is formed, one or more dielectric/conductor layers formed of conductor layers 105, 107, 109 and dielectric layers 104, 106, 108 on the conductor layers, and formed in layers below the surface conductor layers, a pad region 102 formed while bonded to the surface conductor layer by the transmission line, and slits 110 formed in one or more conductors positioned below the pad region to separate a region below the pad region from other regions. Consequently, presence of a region positioned at a periphery of the region below the pad region does not contribute to generation of an electrostatic capacity component, so a decrease in impedance in the pad region is suppressed to suppress mismatching of impedance caused between the transmission line and pad region. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit board for high-frequency signal transmission.

  A circuit board for high-frequency signal transmission requires impedance matching on a transmission line formed on the surface conductor layer in order to perform signal transmission normally. This is because if the transmission signal is reflected due to local impedance mismatch, the transmission characteristics of the high-frequency signal are deteriorated.

  In particular, in the pad portion formed by being joined to the transmission line (wiring pattern) formed on the surface conductor layer, the pad portion is formed wider than the transmission line, and the impedance is lower than that of the transmission line. The transmission signal is reflected due to the mismatch, and the transmission characteristic of the high-frequency signal is deteriorated. In addition, when a differential signal is transmitted using a pair of adjacent transmission lines, a pair of pad portions are joined to the transmission line, but the transmission characteristics of the high-frequency signal deteriorate due to the mismatch of the differential impedance. May end up.

  For this reason, Patent Document 1 below discloses a circuit board in which a drawing portion is provided in a conductor layer located immediately below a pad portion in parallel with the traveling direction of a transmission signal to suppress a reduction in impedance. Patent Document 2 below has a pad region composed of a pair of pad portions adjacent via a separation portion, and corresponds to the pair of pad portions and the separation portion among the conductor layers located immediately below the pad region. A circuit board is described in which the area is removed to suppress a reduction in impedance. Here, the pair of pad portions are joined to a pair of differential transmission lines that propagate a differential signal.

  The circuit boards described in Patent Documents 1 and 2 adjust the thickness and area of the dielectric layer interposed between the pad portion and the conductor layer located immediately below the pad portion, so that the pad portion and the pad portion The capacitance component generated between the conductor layer located immediately below is reduced, and the decrease in impedance is suppressed.

JP 2002-111230 A JP 2004-228478 A

  However, in the circuit board described in Patent Document 1, the conductor layer located immediately below the pad portion is provided with a lead-out portion, but the region immediately below the pad portion of the conductor layer is completely different from other regions. It is not separated. For this reason, between the pad portion and the conductor layer located immediately below the pad portion, the presence of the peripheral region that is continuous with the region immediately below the pad portion contributes to the generation of the capacitance component. The decrease cannot be sufficiently suppressed. In addition, an electrostatic capacitance component is generated between the pad portion and another conductor layer located below the pad portion, and impedance reduction cannot be sufficiently suppressed.

  Moreover, in the circuit board described in Patent Document 2, when the thickness of the dielectric layer interposed between the pad portion and the conductor layer located immediately below the pad portion is reduced, the pad portion and the conductor layer are not formed. Many electrostatic capacitance components are generated, and a decrease in impedance cannot be sufficiently suppressed. For this reason, it is also conceivable to suppress the generation of the electrostatic capacitance component by removing regions corresponding to the pad portion and the separation portion from all the conductor layers located below the pad portion. However, in this case, there arises a new problem that electromagnetic waves are liable to leak below the circuit board through the region where the conductor layer is removed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel and improved high-frequency signal transmission circuit board capable of suppressing impedance mismatch between a transmission line and a pad region. It is to provide.

  In order to solve the above problems, according to an aspect of the present invention, a surface conductor layer on which a transmission line for high-frequency signal transmission is formed, a conductor layer, and a dielectric layer on the conductor layer, One or more dielectric / conductor layers formed in layers as a lower layer, a pad region formed by joining a surface conductor layer to a transmission line, and one or more conductor layers positioned below the pad region, There is provided a circuit board for high-frequency signal transmission comprising a slit formed so as to separate a lower region from other regions.

  According to such a configuration, of the one or more conductor layers positioned below the pad region, the region below the pad region is separated from the other regions. Thereby, between the pad region and the one or more conductor layers, the presence of the region located around the region below the pad region does not contribute to the generation of the capacitance component, so that the impedance in the pad region is reduced. The impedance mismatch between the transmission line and the pad region can be suppressed. Moreover, although the area | region below a pad area | region is cut | disconnected from the other area | regions among one or more conductor layers, since the area | region below a pad area | region is not necessarily removed completely, it is below a circuit board. The leakage of electromagnetic waves can be suppressed.

  The pad region includes two or more pad portions that are joined to two or more transmission lines and are spaced apart from each other, and one conductor layer located immediately below the pad region is directly below the two or more pad portions. There may be further provided a gap formed so as to separate the regions. Thereby, the fall of the impedance in two or more pad parts can be suppressed.

  Here, the two or more transmission lines may include a pair of differential transmission lines that transmit a differential signal. In this case, the regions immediately below the two or more pad portions of the conductor layer located immediately below the pad portions are separated from each other, thereby suppressing the interference of differential signals generated between the pad portions and suppressing the deterioration of transmission characteristics. can do.

  Moreover, you may further provide the gap formed so that the area | region under the two or more pad parts may mutually be separated in one or more conductor layers other than one conductor layer located immediately under a pad area | region. Thereby, the fall of the impedance in two or more pad parts can further be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the circuit board for a high frequency signal transmission which can suppress the impedance mismatching produced between a transmission line and a pad area | region can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  Hereinafter, the circuit board according to the related art will be described with reference to FIGS. 7 and 8, and the circuit board for high-frequency signal transmission according to the embodiment of the present invention will be described with reference to FIGS.

[1. Prior Art Circuit Board]
A conventional circuit board will be described with reference to FIGS. FIG. 7 is a diagram showing a structure of a circuit board for differential signal transmission to which the structure of the circuit board described in Patent Document 1 is applied as the structure of the circuit board according to the prior art. 7A is a plan view of the circuit board, and FIGS. 7B, 7C, and 7D are cross sections along the planes S7b-S7b, S7c-S7c, and S7d-S7d shown in FIG. 7A. FIG.

  As shown in FIG. 7, the circuit board includes a surface conductor layer in which the transmission line 701 and the pad region 702 are formed, a first dielectric layer 704 and a first conductor that are sequentially formed below the surface conductor layer. A layer 705, a second dielectric layer 706, a second conductor layer 707, a third dielectric layer 708, and a third conductor layer 709 are included. Further, a pair of adjacent transmission lines 701 and a pad region 702 are formed on the surface conductor layer so as to be separated by a predetermined distance. The pad region 702 is formed with a pair of adjacent pad portions 703 that are separated by a predetermined distance, and the pair of pad portions 703 are formed by being joined to the pair of transmission lines 701. Here, the pair of transmission lines 701 propagates differential signals.

  As shown in FIG. 7, on the circuit board, the first conductor layer 705 located immediately below the pad region 702 is parallel to the direction in which the transmission line 701 is drawn out (corresponding to the left-right direction in FIG. 7A). A drawing part 710 is provided. In the drawing portion 710, the removed conductor is replaced with a dielectric.

  In the region where the extracted portion 710 is provided immediately below the pad region 702, the distance between the pad region 702 and the second conductor layer 707 is regarded as the thickness of the dielectric layer, but in the region where the extracted portion 710 is not provided. The distance between the pad region 702 and the first conductor layer 705 is regarded as the thickness of the dielectric layer. Thus, the transmission line 701 and the pad part 703 are adjusted by adjusting the area ratio between the area where the punched-out part 710 is provided and the area where it is not provided so that the impedance of the transmission line 701 is equal to the impedance of the pad part 703. Impedance matching is achieved.

  However, in the circuit board, the first conductor layer 705 located immediately below the pad region 702 is provided with the drawing portion 710, but the region immediately below the pad region 702 in the first conductor layer 705 is the other region. It is not completely separated from the area.

  Therefore, a peripheral region that is continuous with the region immediately below the pad region 702 between the pad region 702 and the first to third conductor layers 705, 707, and 709, particularly between the first conductor layer 705. The presence of (a region corresponding to the left and right of the pad region 702 shown in FIG. 7A) contributes to the generation of the electrostatic capacitance component, so that a decrease in impedance cannot be sufficiently suppressed. In addition, a capacitance component is also generated between the pad region 702 and the second conductor layer 707, and a reduction in impedance cannot be sufficiently suppressed.

  Further, when a differential signal is transmitted to the pair of transmission lines 701, interference of the differential signal may occur through a peripheral region that is continuous with a region immediately below the pad region 702. In this case, external noise coupled in phase to the pair of transmission lines 701 during transmission cannot be canceled appropriately, and the transmission characteristics of the differential signal are deteriorated.

  FIG. 8 is a diagram showing a structure of a circuit board described in Patent Document 2 as another structure of the circuit board according to the prior art. 8A is a plan view of the circuit board, and FIGS. 8B, 8C, and 8D are cross sections along planes S8b-S8b, S8c-S8c, and S8d-S8d shown in FIG. 8A. FIG.

  As shown in FIG. 8, the circuit board includes a surface conductor layer on which the transmission line 801 and the pad region 802 are formed, a first dielectric layer 804, a first conductor layer 805, a second dielectric layer 806, a first dielectric layer 806, and a second dielectric layer 806. 2 conductor layers 807, a third dielectric layer 808, and a third conductor layer 809. In addition, a pair of transmission lines 801 and a pad region 802 that are separated by a predetermined distance and are adjacent to each other are formed on the surface conductor layer. The pad region 802 is formed with a pair of adjacent pad portions 803 that are separated by a predetermined distance, and the pair of pad portions 803 are formed by being joined to the pair of transmission lines 801.

  As shown in FIG. 8, a region corresponding to a pair of pad portions 803 and a separation portion between the pad portions 803 is removed from the first conductive layer 805 located immediately below the pad region 802 on the circuit board. In the first conductor layer 805, the removed conductor is replaced with a dielectric. Furthermore, the impedance between the pair of pad portions 803 can be adjusted by adjusting the thickness and area of the region removed from the first conductor layer 805.

  However, in the circuit board, when the thickness of the dielectric layer interposed between the pad region 802 and the first conductor layer 805 located immediately below the pad region 802 decreases, the pad region 802 and the first conductor layer 805 are reduced. Many electrostatic capacitance components are generated between the two and the impedance cannot be sufficiently suppressed. For this reason, generation | occurrence | production of an electrostatic capacitance component is suppressed by removing the area | region corresponding to the pad part 803 and a separation part among the 1st-3rd conductor layers 805, 807, 809 located under the pad area | region 802. It is also possible to do. However, in this case, there arises a new problem that electromagnetic waves are liable to leak below the circuit board through the region where the conductor layer is removed.

[2. Circuit board for high-frequency signal transmission according to the present invention]
Next, a circuit board for high-frequency signal transmission according to the present invention will be described with reference to FIGS.

[2-1. Circuit board according to first embodiment]
A circuit board according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a structure of a circuit board according to the first embodiment. FIG. 1 (a) is a plan view thereof, and FIGS. 1 (b), (c), (d), and (e) are diagrams. FIG. 2 is a cross-sectional view taken along planes S1b-S1b, S1c-S1c, S1d-S1d, and S1e-S1e shown in FIG.

  As shown in FIG. 1, the circuit board includes a surface conductor layer on which the transmission line 101 and the pad region 102 are formed, a first dielectric layer 104 and a first conductor that are sequentially formed below the surface conductor layer. The layer 105 includes a second dielectric layer 106, a second conductor layer 107, a third dielectric layer 108, and a third conductor layer 109. The circuit board may be configured to include a fourth dielectric layer, a fourth conductor layer,... Sequentially formed below the third conductor layer 109. In addition, a transmission line 101 and a pad region 102 including one pad portion 103 are formed on the surface conductor layer.

  As shown in FIG. 1, in the circuit board, slits are formed in the first to third conductor layers 105, 107, and 109 located below the pad region 102 so as to separate the region below the pad region 102 from other regions. 110 is formed. In the slit 110, the conductor removed to form the slit 110 is replaced with a dielectric. Here, the slit 110 is formed so as to border the entire outline of the pad region 102 without overlapping with the pad region 102 located above. The slit 110 functions as an insulating portion that insulates a region below the pad region 102 among the first to third conductor layers 105, 107, and 109 from other regions.

  In FIG. 1A, the slit 110 is shown with a constant width, but the slit 110 may not be formed with a constant width. In particular, in the joint portion between the transmission line 101 and the pad portion 103 corresponding to FIG. 1C, the slit 110 insulates the region below the pad region 102 from other regions, and the transmission line 101 and the pad portion 103. And a width capable of signal transmission.

  As a result, the generation of electrostatic capacitance components between the pad region 102 and the first to third conductor layers 105, 107, and 109 is separated by the slit 110 below the pad region 102 area and the pad region 102. Defined by the area of each region. Therefore, the presence of the region located in the periphery of the region below the pad region 102 (the region corresponding to the top, bottom, left, and right of the pad region 102 shown in FIG. 1A) does not contribute to the generation of the capacitance component. It is possible to suppress a decrease in impedance at 102 and to suppress impedance mismatch between the transmission line 101 and the pad portion 102. The slit 110 is formed with an appropriate width so that the insulating function can be appropriately exerted and the presence of a region located around the region below the pad region 102 does not contribute to the generation of the capacitance component.

  In addition, the slits 110 corresponding to the pad region 102 are formed in the first to third conductor layers 105, 107, and 109, but compared with the case where all the regions corresponding to the pad region 102 are removed. Electromagnetic waves leaking downward can be suppressed.

[2-2. Circuit board according to a modification of the first embodiment]
A circuit board according to a modification of the first embodiment of the present invention will be described with reference to FIG. In addition, below, the description which overlaps with the circuit board which concerns on 1st Embodiment is abbreviate | omitted. FIG. 2 is a diagram illustrating a structure of a circuit board according to a modification of the first embodiment. FIG. 2A is a plan view thereof, and FIG. 2B, FIG. 2C, FIG. e) is a cross-sectional view along the planes S2b-S2b, S2c-S2c, S2d-S2d, and S2e-S2e shown in FIG.

  As shown in FIG. 2, in the circuit board, slits are formed in the first to third conductor layers 205, 207, and 209 located below the pad region 202 so as to separate the region below the pad region 202 from other regions. 210 is formed. Here, the slit 210 is formed so as to partially overlap the pad region 202 located above and border the entire outline of the pad region 202.

  As a result, the generation of the electrostatic capacitance component between the pad region 202 and the first to third conductor layers 205, 207, and 209 is separated by the slit 210 below the pad region 202 area and the pad region 202. Defined by the area of each region. Here, in the circuit board according to the modification, the area of the area separated from the other area as the area below the pad area 202 is relatively reduced as compared with the circuit board according to the first embodiment. Therefore, the generation of the capacitance component is relatively suppressed.

  As described above, according to the circuit board according to the first embodiment of the present invention, among the one or more conductor layers 105, 107, 109; 205, 207, 209 located below the pad region 102; , The area below the pad area 102; 202 is separated from the other areas. As a result, the presence of a region located around the region below the pad region 102; 202 is static between the pad region 102; 202 and the one or more conductor layers 105, 107, 109; 205, 207, 209. Since it does not contribute to the generation of the capacitance component, it is possible to suppress a decrease in impedance in the pad region 102; 202 and to suppress impedance mismatch between the transmission line 101; 201 and the pad region 102; 202.

  Of the one or more conductor layers 105, 107, 109; 205, 207, 209, the region below the pad region 102; 202 is separated from the other regions, but the region below the pad region 102; Since it is not completely removed, leakage of electromagnetic waves below the circuit board can be suppressed.

[2-3. Circuit Board According to Second Embodiment]
A circuit board according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing the structure of the circuit board according to the second embodiment. FIG. 3A is a plan view thereof, and FIGS. 3B, 3C, 3D, and 3E are FIGS. FIG. 4 is a cross-sectional view taken along planes S3b-S3b, S3c-S3c, S3d-S3d, and S3e-S3e shown in FIG.

  As shown in FIG. 3, the circuit board includes a surface conductor layer in which the transmission line 301 and the pad region 302 are formed, a first dielectric layer 304 and a first conductor that are sequentially formed below the surface conductor layer. The layer 305 includes a second dielectric layer 306, a second conductor layer 307, a third dielectric layer 308, and a third conductor layer 309. The circuit board may be configured to include a fourth dielectric layer, a fourth conductor layer,... Sequentially formed below the third conductor layer 309.

  In addition, a pair of transmission lines 301 and a pad region 302 which are separated by a predetermined distance and are adjacent to each other are formed on the surface conductor layer. The pad region 302 is formed with a pair of adjacent pad portions 303 that are separated by a predetermined distance, and the pair of pad portions 303 are formed by being joined to the pair of transmission lines 301. Here, the pair of transmission lines 301 function as a differential transmission line that propagates a differential signal.

  As shown in FIG. 3, in the circuit board, the first to third conductor layers 305, 307, and 309 located below the pad region 302 are slit so as to separate the region below the pad region 302 from other regions. 310 is formed. In the slit 310, the conductor removed to form the slit 310 is replaced with a dielectric. Here, the slit 310 is formed so as to border the entire outline of the pad region 302 without overlapping the pad region 302 positioned above. The slit 310 functions as an insulating portion that insulates a region below the pad region 302 of the first to third conductor layers 305, 307, and 309 from other regions.

  In FIG. 3A, the slit 310 is shown with a constant width, but the slit 310 may not be formed with a constant width. In particular, in the joint portion between the transmission line 301 and the pad portion 303 corresponding to FIG. 3C, the slit 310 insulates the region below the pad region 302 from other regions, and the transmission line 301 and the pad portion 303. And a width capable of signal transmission.

  As a result, the generation of the electrostatic capacitance component between the pad region 302 and the first to third conductor layers 305, 307, and 309 is separated by the slit 310 below the pad region 302 area and the pad region 302. Defined by the area of each region. Therefore, the presence of regions located in the periphery of the region below the pad region 302 (regions corresponding to the top, bottom, left and right of the pad region 302 shown in FIG. 3A) does not contribute to the generation of the capacitance component. It is possible to suppress a decrease in impedance at 302 and to suppress impedance mismatch between the pair of transmission lines 301 and the pair of pad portions 303.

  In addition, a gap 312 is formed in the first conductor layer 305 located immediately below the pad region 302 so as to separate the regions below the pair of pad portions 303 from each other. Thereby, the generation of the electrostatic capacitance component between the pad portion 303 and the first conductor layer 305 is defined by the area of the pad portion 303 and the area of the region immediately below the pad portion 303. Therefore, the presence of the region located in the vicinity of the region immediately below the pad portion 303 does not contribute to the generation of the electrostatic capacitance component, so that a reduction in impedance at the pad portion 303 is suppressed, and the impedance generated between the pair of pad portions 303. Inconsistency can be suppressed. Also, differential signal interference is less likely to occur through a region located around the region immediately below the pad portion 303, so that the transmission characteristics of the differential signal are not deteriorated.

  In addition, the first to third conductor layers 305, 307, and 309 have slits 310 corresponding to the pad region 302. Compared to the case where the entire region corresponding to the pad region 302 is removed, the circuit board has Electromagnetic waves leaking downward can be suppressed.

[2-4. Circuit board according to a modification of the second embodiment]
A circuit board according to Modifications 1 to 3 of the second embodiment of the present invention will be described with reference to FIGS. In addition, below, the description which overlaps with the circuit board which concerns on 2nd Embodiment is abbreviate | omitted.

  FIG. 4 is a diagram illustrating a structure of a circuit board according to Modification 1 of the second embodiment. FIG. 4A is a plan view thereof, and FIGS. 4B, 4C, 4D, (E) is sectional drawing along surface S4b-S4b, S4c-S4c, S4d-S4d, S4e-S4e shown to Fig.4 (a).

  As shown in FIG. 4, in the circuit board, gaps 412 are formed in the first to third conductor layers 405, 407, and 409 located below the pad region 402 so that the regions below the pair of pad portions 403 are separated from each other. Is formed. Thereby, the generation of the electrostatic capacitance component between the pad portion 403 and the first to third conductor layers 405, 407, and 409 is defined by the area of the pad portion 403 and the area of the region below the pad portion 403. Is done. Therefore, the presence of a region located around the region below the pad portion 403 does not contribute to the generation of the electrostatic capacitance component, so that a decrease in impedance at the pad portion 403 is suppressed, and the impedance generated between the pair of pad portions 403. Inconsistency can be suppressed.

  The first to third conductor layers 405, 407, and 409 are formed with a gap 412 corresponding to a separation portion between the pair of pad portions 403, but when all the regions corresponding to the pad region 402 are removed. In comparison, electromagnetic waves that leak below the circuit board can be suppressed.

  FIG. 5 is a diagram illustrating a structure of a circuit board according to the second modification of the second embodiment. FIG. 5A is a plan view thereof, and FIGS. 5B, 5C, 5D, (E) is sectional drawing along surface S5b-S5b, S5c-S5c, S5d-S5d, S5e-S5e shown to Fig.5 (a).

  As shown in FIG. 5, in the circuit board, slits are formed in the first to third conductor layers 505, 507, and 509 located below the pad region 502 so as to separate the region below the pad region 502 from other regions. 510 is formed. Here, the slit 510 is formed so as to partially overlap the pad region 502 located above and border the entire outline of the pad region 502.

  As a result, the generation of electrostatic capacitance components between the pad region 502 and the first to third conductor layers 505, 507, and 509 is separated by the slit 510 below the area of the pad region 502 and the pad region 502. Defined by the area of each region. Here, in the circuit board according to the second modification, the area of the area separated from the other areas as the area below the pad area 502 is relatively reduced as compared with the circuit board according to the second embodiment. Therefore, the generation of the capacitance component is relatively suppressed.

  FIG. 6 is a diagram illustrating a structure of a circuit board according to Modification 3 of the second embodiment. FIG. 6A is a plan view thereof, and FIGS. 6B, 6C, 6D, (E) is sectional drawing along surface S6b-S6b, S6c-S6c, S6d-S6d, and S6e-S6e shown to Fig.6 (a).

  As shown in FIG. 6, in the circuit board, the first to third conductor layers 605, 607, and 609 located below the pad region 602 are slit so as to separate the region below the pad region 602 from other regions. 610 is formed. Here, the slit 610 is formed such that the lower the conductor layer, the larger the region partially overlapping with the upper pad region 602.

  As a result, the generation of the capacitance component between the pad region 602 and the first to third conductor layers 605, 607, and 609 is separated by the slit 610 from the area of the pad region 602 and below the pad region 602. Defined by the area of each region. Here, in the circuit board according to the modified example 3, as compared with the circuit board according to the second embodiment, the area of the area separated from the other area as the area below the pad area 602 is reduced as the conductor layer is below. Therefore, the spread of the electric lines of force to the outside can be suppressed.

  The circuit board according to the first to third modifications of the second embodiment includes the first conductor layers 405; 505; 605 located immediately below the pad regions 402; 502; 602, and the pad regions 402; 502; All the conductor layers located below 602 (first to third conductor layers 405, 407, 409; 505, 507, 509; 605, 607, 609) are below the pair of pad portions 403; 503; 603 The gaps 412; 512; 612 are formed so as to separate the regions of each other. However, on the first conductor layers 405; 505; 605 and either the second or third conductor layers 407, 409; 507, 509; 607, 609 located below the pad regions 402; 502; 602. The gaps 412; 512; 612 may be formed so as to separate regions below the pair of pad portions 403; 503; 603 from each other.

  As described above, according to the circuit board according to the second embodiment of the present invention, in addition to the effect of the circuit board according to the first embodiment, two or more pad portions 303; 403; 503; The decrease in impedance can be suppressed. Also, the conductor layers 305; 405; 505; 605, or the conductor layers 305, 307, 309; 405, 407, 409; 505, 507, 509; 605, 607, 609, two or more pad portions 303; 403; 503 ; The regions immediately below 603 are separated from each other, so that interference of differential signals generated between the pad portions 303; 403; 503; 603 can be suppressed, and deterioration of transmission characteristics can be suppressed.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to the example which concerns. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, in the description according to the above embodiment, the circuit board including the surface conductor layer and the three dielectric / conductor layers has been described. However, the present invention can be similarly applied to a circuit board including a surface conductor layer and one or more dielectric / conductor layers.

  Moreover, although each component of a circuit board is shown by FIGS. 1-6, FIGS. 1-6 is for demonstrating the concept of the circuit board which concerns on embodiment of this invention. For this reason, the dimensions, shapes, and the like of the components shown in FIGS. 1 to 6 should be understood as references only.

It is a figure which shows the structure of the circuit board which concerns on 1st Embodiment. It is a figure which shows the structure of the circuit board which concerns on the modification of 1st Embodiment. It is a figure which shows the structure of the circuit board which concerns on 2nd Embodiment. It is a figure which shows the structure of the circuit board which concerns on the modification 1 of 2nd Embodiment. It is a figure which shows the structure of the circuit board which concerns on the modification 2 of 2nd Embodiment. It is a figure which shows the structure of the circuit board which concerns on the modification 3 of 2nd Embodiment. It is a figure which shows the structure of the circuit board based on a prior art. It is a figure which shows the other structure of the circuit board based on a prior art.

Explanation of symbols

101, 201, 301, 401, 501, 601 Transmission line 102, 202, 302, 402, 502, 602 Pad area 103, 203, 303, 403, 503, 603 Pad part 104, 204, 304, 404, 504, 604 First dielectric layer 105, 205, 305, 405, 505, 605 First conductor layer 106, 206, 306, 406, 506, 606 Second dielectric layer 107, 207, 307, 407, 507, 607 Second conductor layer 108, 208, 308, 408, 508, 608 Third dielectric layer 109, 209, 309, 409, 509, 609 Third conductor layer 110, 210, 310, 410, 510, 610 Slit 312, 412, 512, 612 gap

Claims (4)

A surface conductor layer on which a transmission line for high-frequency signal transmission is formed;
A dielectric layer composed of a conductor layer and a dielectric layer on the conductor layer, and is formed as one or more layers as a lower layer of the surface conductor layer; and
A pad region formed by bonding to the transmission line on the surface conductor layer;
A slit formed in one or more conductor layers located below the pad region so as to separate the region below the pad region from other regions;
A circuit board for high-frequency signal transmission, comprising: The pad region includes two or more pad portions that are bonded to two or more transmission lines and are spaced apart from each other.
The circuit board for high frequency signal transmission according to claim 1, further comprising a gap formed in one conductor layer located immediately below the pad region so as to separate the regions immediately below the two or more pad portions from each other.   The circuit board for high-frequency signal transmission according to claim 2, wherein the two or more transmission lines include a pair of differential transmission lines for transmitting a differential signal.   3. The gap according to claim 2, further comprising a gap formed in one or more conductor layers other than the one conductor layer located immediately below the pad region so as to separate regions below the two or more pad portions from each other. Circuit board for high frequency signal transmission.

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