JP2013093521A - Differential transmission line and multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential transmission line capable of transmitting a high frequency signal efficiently by reducing the impact of external noise, and to provide a multilayer wiring board including the differential transmission line.SOLUTION: In a differential transmission line consisting of a pair of wiring conductors having a first wiring conductor 2 and a second wiring conductor 3 facing each other vertically with an insulation layer therebetween, the end of one first wiring conductor 2a and the end of the other first wiring conductor 2b are connected electrically via a first through conductor 4 provided to penetrate the insulation layer, the end of one second wiring conductor 3a and the end of the other second wiring conductor 3b are connected electrically via a second through conductor 5 provided to penetrate the insulation layer, and a ground through conductor 6 is provided between the first through conductor 4 and the second through conductor 5. Impact of external noise is reduced, and a high frequency signal can be transmitted efficiently.

Description

  The present invention relates to a differential transmission line configured by a pair of wiring conductors facing each other with an insulating layer interposed therebetween, and transmitting an electric signal through the pair of wiring conductors.

  In the internal wiring structure of package mounting parts and semiconductor parts that are mounted and sealed with semiconductor elements such as ICs and LSIs that operate at high speeds and surface mountable electronic parts, differential is intended to propagate high-speed high-frequency signals accurately and efficiently. A transmission line structure is adopted. This differential transmission line structure is a structure in which one signal is transmitted using two signal lines.

  In such a differential transmission line structure, there is a differential transmission line structure in which a pair of wiring conductors are arranged so as to face each other up and down across an insulating layer inside an insulating base formed by laminating a plurality of insulating layers. there were.

  Conventionally, in such a differential transmission line structure, there has been disclosed a structure in which upper and lower wiring conductors are divided and electrically connected so as to be switched up and down (intersect) via a through conductor (for example, , See Patent Document 1).

JP-A-7-95134

  However, in the conventional differential transmission line, on the surface of the insulating layer, the signals transmitted through the pair of signal wiring conductors are in the same direction and have a differential transmission line structure. There has been a phenomenon that the signals transmitted through the through conductors are reversed and the pair of through conductors do not have a differential transmission line structure. As a result, the pair of through conductors does not have a differential wiring structure, so when noise enters from the through conductor, the noise is not canceled when the signal is synthesized on the receiving side, so high-frequency signals are transmitted efficiently. There was a problem that it was difficult to do.

  The present invention has been completed in view of the above problems, and its purpose is to reduce the influence of external noise in a pair of through conductors and to efficiently transmit a high-frequency signal and An object of the present invention is to provide a multilayer wiring board provided with the differential transmission line.

The differential transmission line of the present invention is a differential transmission line comprising a pair of wiring conductors having a first wiring conductor and a second wiring conductor facing each other up and down across an insulating layer, wherein the first wiring conductor is one of the first wiring conductors. One wiring conductor and the other first wiring conductor, and the second wiring conductor has one second wiring conductor and the other second wiring conductor, and the one first wiring conductor and the first wiring conductor One second wiring conductor is vertically opposed across the insulating layer, and the other first wiring conductor and the other second wiring conductor are vertically opposed across the insulating layer, An end of the one first wiring conductor and an end of the other first wiring conductor are electrically connected via a first through conductor provided so as to penetrate the insulating layer, and the one first wiring conductor An end of the two wiring conductors and an end of the other second wiring conductor are provided through the insulating layer. Was are electrically connected via the second through conductor, it is characterized in that the ground through conductors are provided between the first through conductor and the second through-conductors.

  In addition, the multilayer wiring board of the present invention includes the differential transmission line of the present invention having the above-described configuration inside an insulating substrate formed by laminating a plurality of insulating layers, and is provided on one main surface and the other main surface of the insulating substrate. A ground conductor layer is formed, and the ground through conductor is connected to the ground conductor layer.

  According to the differential transmission line of the present invention, the end of one first wiring conductor and the end of the other first wiring conductor are electrically connected via the first through conductor provided through the insulating layer. And an end of one second wiring conductor and an end of the other second wiring conductor are electrically connected via a second through conductor provided through the insulating layer, Since the grounding through conductor is provided between the first through conductor and the second through conductor, the electromagnetic coupling generated between the first through conductor and the second through conductor can be weakened. It becomes difficult for noise to ride on the through conductor and the second through conductor. As a result, it is possible to reduce the influence of noise from the outside and efficiently transmit a high-frequency signal.

  In addition, according to the multilayer wiring board of the present invention, the differential transmission line of the present invention having the above-described configuration is provided inside the insulating substrate formed by laminating a plurality of insulating layers, and one main surface and the other main surface of the insulating substrate. The ground conductor layer is formed on the ground conductor layer, and the ground through conductor is connected to the ground conductor layer, so that the electromagnetic field coupling generated between the first through conductor and the second through conductor by the ground through conductor. This makes it difficult for noise to ride on the first through conductor and the second through conductor, and reduces the influence of external noise by the ground conductor layer formed on one main surface and the other main surface of the insulating base. Therefore, it is possible to efficiently transmit a high frequency signal.

It is a perspective view which shows an example of embodiment of the differential transmission line and multilayer wiring board of this invention. (A) is a top view which shows the other example of embodiment of the differential transmission line of this invention, and a multilayer wiring board, (b) is sectional drawing in the XX of (a). (A) is a top view which shows the other example of embodiment of the differential transmission line of this invention, and a multilayer wiring board, (b) is sectional drawing in the XX of (a). It is a principal part enlarged plan view which shows the other example of embodiment of the differential transmission line of this invention. It is a principal part enlarged plan view which shows the other example of embodiment of the differential transmission line of this invention. It is a principal part enlarged plan view which shows the other example of embodiment of the differential transmission line of this invention. It is a disassembled perspective view which shows the other example of embodiment of the differential transmission line and multilayer wiring board of this invention.

  The differential transmission line and multilayer wiring board of the present invention will be described in detail below.

FIG. 1 is a perspective view showing an example of an embodiment of a differential transmission line and a multilayer wiring board according to the present invention. FIG. 2A is a top view of the multilayer wiring board of the example shown in FIG. 1 as viewed from above, and a pair of wiring conductors are shown through. FIG.2 (b) is sectional drawing in the XX line of Fig.2 (a). 1 and 2 (a) and 2 (b) show examples in which there are three insulating layers, 1a being a first insulating layer, 1b being a second insulating layer, and 1c being a third insulating layer, The insulating substrate 1 is formed by laminating these. Reference numeral 2 denotes a first wiring conductor, 3 denotes a second wiring conductor, and the first wiring conductor 2 and the second wiring conductor 3 are a pair of wiring conductors to form a differential transmission line structure. Among the first wiring conductors 2, 2 a is one first wiring conductor and 2 b is the other first wiring conductor. Of the second wiring conductor 3, 3a is one second wiring conductor, and 3b is the other second wiring conductor. One first wiring conductor 2a and one second wiring conductor 3a are vertically opposed to each other with an insulating layer interposed therebetween, and the other first wiring conductor 2b and the other second wiring conductor 3b are provided with an insulating layer. It is arranged facing the top and bottom across. The electrical connection of these wiring conductors will be described below.

  The end of one first wiring conductor 2a and the end of the other first wiring conductor 2b are electrically connected via a first through conductor 4 provided through the insulating layer, and The end of one second wiring conductor 3a and the end of the other second wiring conductor 3b are electrically connected via a second through conductor 5 provided so as to penetrate the insulating layer. In this way, the first wiring conductor 2 and the second wiring conductor 3 formed vertically with the insulating layer interposed therebetween are switched up and down via the first through conductor 4 and the second through conductor 5 so as to cross each other. Has been. Reference numeral 6 denotes a ground through conductor, which is provided between the first through conductor 4 and the second through conductor 5.

  The differential transmission line of the present invention has a first wiring conductor 2 and a second wiring conductor 3 which are opposed to each other with an insulating layer interposed therebetween, as in the examples shown in FIGS. 1 and 2A and 2B. In the differential transmission line composed of a pair of wiring conductors, the first wiring conductor 2 has one first wiring conductor 2a and the other first wiring conductor 2b, and the second wiring conductor 3 is one second wiring conductor. 3a and the other second wiring conductor 3b. One first wiring conductor 2a and one second wiring conductor 3a are vertically opposed to each other with an insulating layer interposed therebetween, and the other first wiring conductor. 2b and the other second wiring conductor 3b are vertically opposed to each other with an insulating layer interposed therebetween, and an end portion of one first wiring conductor 2a and an end portion of the other first wiring conductor 2b penetrate the insulating layer. Are electrically connected via the first through conductor 4 provided in the same manner, and the end of one second wiring conductor 3a and the other The second wiring conductor 3b is electrically connected to the end of the second wiring conductor 3b through a second through conductor 5 penetrating the insulating layer, and between the first through conductor 4 and the second through conductor 5. Is provided with a ground through conductor 6. With such a configuration, since the grounding through conductor 6 is provided between the first through conductor 4 and the second through conductor 5, it occurs between the first through conductor 4 and the second through conductor 5. Electromagnetic field coupling can be weakened. As a result, even if signals transmitted through the first through conductor 4 and the second through conductor 5 are in the reverse direction and do not have a differential transmission line structure, the first through conductor and the second through conductor Since it is difficult for noise to ride on the conductor, it is possible to reduce the influence of noise from the outside and efficiently transmit a high-frequency signal.

  Specifically, an electromagnetic field coupling occurs between the first through conductor 4 and the second through conductor 5 because the direction of the signal transmitted through the first through conductor 4 and the second through conductor 5 is reversed. As a result, noise is generated by electromagnetic field coupling, and this noise is ridden on the first through conductor 4 and the second through conductor 5. In order to cut off the magnetic field flow of the electric field distribution generated by the electromagnetic field coupling and weaken the electromagnetic field coupling generated between the first through conductor 4 and the second through conductor 5, the first through conductor 4 and the second A grounding through conductor 6 is provided between the through conductor 5. In addition, it is preferable to provide the grounding through conductor 6 in order to effectively cut off the magnetic field of electromagnetic coupling by providing the grounding through conductor 6 along the magnetic field flow of the electric field distribution.

  In the differential transmission line according to the present invention, the grounding through conductor 6 is connected to the center of the first through conductor 4 and the first through conductor 4 as shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b). It is preferable that the center of the first through conductor 4 and the center of the second through conductor 5 be provided at a position that bisects the straight line connecting the centers of the two through conductors 5. In this case, since the electromagnetic field coupling is strongest on the straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5, the electromagnetic field coupling can be effectively performed by providing the ground through conductor 6 in this portion. Can be weakened. As a result, the influence of external noise can be reduced and a high-frequency signal can be transmitted more efficiently.

Furthermore, the grounding through conductor 6 is provided at a position that bisects the center of the first through conductor 4 and the center of the second through conductor 5, so that the first through conductor 4, the second through conductor 5, and the ground When the diameters of the through conductors 6 are the same, the center of the ground through conductor 6 is provided at a position that bisects the center of the first through conductor 4 and the center of the second through conductor 5. Ground through conductor 6 and first
Since the distance between the through conductor 4 and the distance between the ground through conductor 6 and the second through conductor 5 are equal, the characteristic impedances of the first through conductor 4 and the second through conductor 5 have the same value. This is preferable because the generation of noise due to the difference can be suppressed.

  That is, if the distance between the ground through conductor 6 and the first through conductor 4 and the distance between the ground through conductor 6 and the second through conductor 5 are different, the respective characteristic impedances of the first through conductor 4 and the second through conductor 5 are different. Since the noise is generated by the different characteristic impedance and this noise is on the first through conductor 4 and the second through conductor 5, in order to suppress this, the present invention The through conductor 6 is provided at a position that bisects the center of the first through conductor 4 and the center of the second through conductor 5, and the distance between the ground through conductor 6 and the first through conductor 4 and the ground through conductor 6 and the second through conductor 6. The distance to the through conductor 5 is made equal.

As an example, the diameter of each of the first through conductor 4, the second through conductor 5, and the ground through conductor 6 is 0.2 mm with the same dimensions, and the insulating layer is made of 95% alumina having a relative dielectric constant of 9.5. When the center-to-center distance between the conductor 6 and the first through conductor 4 and the center-to-center distance between the ground through conductor 6 and the second through conductor 5 are each 0.46 mm, the first through conductor 4 and the second through conductor 5 Since the impedance is about 50Ω respectively, the impedance of the pair of wiring conductors is set when the impedance of the differential wiring between the first wiring conductor and the second wiring conductor is set to 100Ω and a signal of 50Ω impedance is transmitted. Is 50Ω, and the impedance of the through conductor is also 50Ω. This is preferable because there is no change in impedance when a signal is transmitted from the wiring conductor to the through conductor, and the deterioration of transmission characteristics is reduced. There. In this case, the distance between the centers of the first through conductor 4 and the second through conductor 5 is 9.2 mm, and the center of the ground through conductor 6 is the first through conductor 4.
In addition, it is formed at a position where the center of the second through conductor 5 is divided into two.

  In the differential transmission line of the present invention, as in the example shown in FIG. 4, the grounding through conductor 6 includes the center of the first through conductor 4 and the second through conductor inside the first through conductor 4 and the second through conductor 5. It is preferable that a plurality are provided in a direction orthogonal to a straight line connecting the centers of the five. In this case, on the straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5, the center of the first through conductor 4 and the center of the second through conductor 5 are divided into two. Thus, a magnetic field of electric field distribution is formed concentrically, so that in addition to the strongest electromagnetic coupling magnetic field on the straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5, It is possible to easily cut off the electromagnetic field coupling magnetic field generated by the ground through conductor 6 and weaken the electromagnetic field coupling. As a result, the influence of external noise can be reduced and a high-frequency signal can be transmitted more efficiently.

  In the differential transmission line of the present invention, as shown in the example shown in FIG. 5, it is preferable that a plurality of ground through conductors 6 are provided around the outside of the first through conductor 4 and the second through conductor 5. In this case, the grounding through conductor 6 provided around the outside of the first through conductor 4 and the second through conductor 5 improves the grounding property, and noise is externally applied to the first through conductor 4 and the second through conductor 5. The high frequency signal can be transmitted more efficiently. Specifically, the outside of the first through conductor 4 and the second through conductor 5 provided with the ground through conductor 6 is surrounded by the first wiring conductor 2 and the second wiring conductor 3 when viewed from above. It is outside the area.

  As shown in the example shown in FIG. 1, the multilayer wiring board according to the present invention has an insulating substrate 1 in which a plurality of insulating layers are stacked (in FIG. 1, three insulating layers are stacked). The differential transmission line of the present invention having the configuration is provided, and a ground conductor layer 7 is formed on one main surface and the other main surface of the insulating base, and a ground through conductor 6 is connected to the ground conductor layer 7. With such a configuration, the grounding through conductor 6 makes it difficult for noise to ride on the first through conductor 4 and the second through conductor 5, and the grounding conductor layer 7 formed on the one main surface and the other main surface of the insulating base 1. Since the influence of external noise can be reduced, high-frequency signals can be transmitted efficiently.

The insulating substrate 1 is composed of a plurality of insulating layers. The insulating layer is made of, for example, an aluminum oxide (alumina: Al ₂ O ₃ ) sintered body, an aluminum nitride (AlN) sintered body, or a silicon carbide (SiC) sintered body. Body, mullite sintered body, and ceramics such as glass ceramics. In the example shown in FIGS. 1 to 3, an example in which the insulating base 1 is composed of three insulating layers is shown. In this example, the third insulating layer 1c, the second insulating layer 1b, and the first insulating layer 1a are sequentially stacked from the bottom, the uppermost layer is the first insulating layer 1a, and the intermediate layer is the second insulating layer 1b. The lowest layer is the third insulating layer 1c.

  The first wiring conductor 2 and the second wiring conductor 3, and the first through conductor 4, the second through conductor 5, and the ground through conductor 6 constituting the pair of wiring conductors are formed of tungsten (W ), Molybdenum (Mo), Molybdenum-Manganese (Mo-Mn) alloy, Silver (Ag), Copper (Cu), Gold (Au), Silver-Palladium (Ag-Pd) alloy, etc. It consists of

  The first wiring conductor 2 has one first wiring conductor 2a and the other first wiring conductor 2b, and the second wiring conductor 3 also has one second wiring conductor 3a and the other second wiring conductor 3b. Have. Then, one first wiring conductor 2a and the other second wiring conductor 3b are formed on the upper surface of the second insulating layer 1b, and the other first wiring conductor 2b and one second wiring conductor 3a are third insulation. It is formed on the upper surface of the layer 1c.

The first through conductor 4 has a function of electrically connecting one first wiring conductor 2a and the other first wiring conductor 2b and has a diameter of 0.05 to 0.2 mm. The required dimensions may be selected according to the required characteristic impedance and wiring density.

The second through conductor 5 has a function of electrically connecting one second wiring conductor 3a and the other second wiring conductor 3b, and has the same dimensions as the first through conductor 4 with a diameter of 0.05 to 0.2 mm. This is preferable because the impedance value can be the same as that of the first through conductor 4.

  The first through conductor 4 and the second through conductor 5 are provided so as to penetrate the second insulating layer 1b, and one first wiring conductor 2a and the other first wiring conductor 2b connect the first through conductor 4 with each other. One second wiring conductor 3 a and the other second wiring conductor 3 b are electrically connected via the second through conductor 5.

  It is important that the grounding through conductor 6 is provided between the first through conductor 4 and the second through conductor 5. With such a configuration, the electromagnetic field coupling generated between the first through conductor 4 and the second through conductor 5 by the ground through conductor 6 provided between the first through conductor 4 and the second through conductor 5. As a result, the influence of external noise can be reduced.

The grounding through conductor 6 has a diameter of 0.05 to 0.2 mm and the same dimensions as the first through conductor 4 and the second through conductor 5, so that the same impedance value as that of the first through conductor 4 and the second through conductor 5 can be obtained. Therefore, it is preferable to provide the ground through conductor 6 along the flow of the magnetic field of the electric field distribution, because it is easy to effectively cut off the magnetic field of the electromagnetic field coupling and weaken the electromagnetic field coupling.

  Specifically, the position where the grounding through conductor 6 is provided is most on the straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5 as in the example shown in FIGS. Since the electromagnetic field coupling is strong, by providing the grounding through conductor 6 in this portion, the magnetic field of the electromagnetic field coupling can be easily cut off effectively, and the electromagnetic field coupling can be weakened.

As shown in the example shown in FIG. 4, the grounding through conductor 6 is formed on a straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5, and the center of the first through conductor 4 and the second through conductor. It is preferable to provide a plurality of 5 so as to be lined up in the horizontal direction on the left and right sides, with the center of 5 being divided into two. In this case, the magnetic field of the electric field distribution by the electromagnetic field coupling is on a straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5, and the center of the first through conductor 4 and the second through conductor 5. Since it is formed in a concentric circle centering on a position that bisects the center, the strongest electromagnetic coupling magnetic field on the straight line connecting the center of the first through conductor 4 and the center of the second through conductor 5 is obtained. In addition, it is possible to more effectively cut off the electromagnetically coupled magnetic field generated around the ground by the grounding through conductor 6. As a result, the electromagnetic field coupling is weakened, the influence of external noise is reduced, and a high-frequency signal can be transmitted more efficiently, which is preferable.

  As shown in the example shown in FIG. 5, the ground penetrating conductor 6 is formed on the straight line connecting the center of the first penetrating conductor 4 and the center of the second penetrating conductor 5. It is preferable to be provided on the outside of each. In this case, the magnetic field of the electric field distribution generated by the electromagnetic coupling generated between the first through conductor 4 and the second through conductor 5 can be effectively cut off easily, weakening the electromagnetic coupling, and reducing the influence of noise. In addition, the ground through conductor 6 provided outside each of the first through conductor 4 and the second through conductor 5 also suppresses noise from entering the first through conductor 4 and the second through conductor 5 from the outside. A high-frequency signal can be transmitted more efficiently.

  In the example shown in FIG. 6, a plurality of ground through conductors 6 are provided between the first through conductor 4 and the second through conductor 5, and a plurality of ground through conductors 6 are also provided around the outside of the first through conductor 4 and the second through conductor 5. It is an example provided. In this case, it is possible to effectively cut off the magnetic field of the electric field distribution generated by the electromagnetic field coupling generated between the first through conductor 4 and the second through conductor 5 and weaken the electromagnetic field coupling. The influence of external noise on the first through conductor 4 and the second through conductor 5 can be reduced, and a high-frequency signal can be transmitted more efficiently.

  The multilayer wiring board of the present invention includes the differential transmission line of the present invention having the above-described configuration inside an insulating substrate 1 in which a plurality of insulating layers are laminated as in the examples shown in FIGS. A ground conductor layer 7 is formed on one main surface and the other main surface of the base body, and a ground through conductor 6 is connected to the ground conductor layer 7.

  The example shown in FIGS. 1 to 3 is an example in which three insulating layers are laminated, and these three insulating layers are the third insulating layer 1c and the second insulating layer 1b as in the example shown in FIG. The first insulating layer 1a is sequentially stacked from the bottom. The example shown in FIG. 7 is an exploded perspective view showing the multilayer wiring board of the present invention in order from the upper layer to the lower layer, and shows through conductors in the first insulating layer 1a, the second insulating layer 1b, and the third insulating layer 1c. These connections are indicated by broken lines. The first through conductor 4 and the second through conductor 5 described above are provided in the central portion of the insulating layer, and the grounding through conductor 6 is provided between these through conductors. A through conductor that is electrically connected to the first wiring conductor 2 and the second wiring conductor 4 is provided on the outer peripheral portion of the insulating layer, and the first wiring conductor 2 and the second wiring conductor 3 are interposed through the through conductor. Is led to a terminal 8 to transmit an electric signal.

  Specifically, the lead-out path to the terminal 8 of the first wiring conductor 2 and the second wiring conductor 3 is the upper surface of the second insulating layer 1b as in the example shown in FIGS. 2 (b) and 3 (b). One of the first wiring conductors 2a and the other second wiring conductor 3b formed in the lead-out are led out to the terminal 8 on one main surface of the insulating base 1 through a through conductor provided through the first insulating layer 1a. Is done. Further, the other first wiring conductor 2b and one second wiring conductor 3a formed on the upper surface of the third insulating layer 1c are through conductors provided through the first insulating layer 1a and the second insulating layer 1b. Through the terminal 8 on one main surface of the insulating substrate 1.

Propagation of the signal line flowing through the first wiring conductor 2 is such that the signal line enters from the terminal 8 on one main surface of the insulating base 1 and passes through the first conductor through the through conductor provided through the first insulating layer 1a. Propagates to the wiring conductor 2a, passes through the first through conductor 4, propagates to the other first wiring conductor 2b, and passes through the through conductor provided through the first insulating layer 1a and the second insulating layer 1b. Then, the path of propagation to the terminal 8 on one main surface of the insulating base 1 is followed.

  Similarly, the propagation of the signal line flowing through the second wiring conductor 3 is provided through the first insulating layer 1a and the second insulating layer 1b, with the signal line entering from the terminal 8 on one main surface of the insulating base 1. Propagating to one second wiring conductor 3a through the through conductor, propagating to the other second wiring conductor 3b through the second through conductor 5, and penetrating through the first insulating layer 1a It follows the path of propagation to the terminal 8 on one main surface of the insulating base 1 via the conductor.

  At this time, the line length of the signal line flowing through the first wiring conductor 2 is the length of one first wiring conductor 2a formed on the upper surface of the second insulating layer 1b and the upper surface of the third insulating layer 1c. The length of the other first wiring conductor 2b and the first through conductor 4 provided through the second insulating layer 1b and electrically connecting one first wiring conductor 2a and the other first wiring conductor 2b. It is a length obtained by adding the length, the length of the through conductor provided through the first insulating layer 1a, and the length of the through conductor provided through the first insulating layer 1a and the second insulating layer 1b. .

  Similarly, the line length of the signal line flowing through the second wiring conductor 3 is the length of one second wiring conductor 3a formed on the top surface of the third insulating layer 1c and the top length of the second insulating layer 1b. The length of the other second wiring conductor 3b and the second through conductor 5 provided through the second insulating layer 1b and electrically connecting one second wiring conductor 3a and the other second wiring conductor 3b. The length is obtained by adding the length of the through conductor provided through the first insulating layer 1a and the length of the through conductor provided through the first insulating layer 1a and the second insulating layer 1b. The length of the signal line flowing through the first wiring conductor 2 is the same as the length of the signal line.

  In this way, in the differential transmission line in which the pair of wiring conductors are arranged so as to face each other with the insulating layer interposed therebetween, one first wiring conductor 2a and the other first wiring conductor 2b penetrate the insulating layer. The second through conductor 5 is electrically connected through the first through conductor 4 provided so that one second wiring conductor 3a and the other second wiring conductor 3b are provided through the insulating layer. Since the first wiring conductor 2 and the second wiring conductor 3 formed above and below the insulating layer are vertically connected to each other via the first through conductor 4 and the second through conductor 5. It will be replaced and connected so as to intersect. As a result, as described above, the line lengths of the first wiring conductor 2 and the second wiring conductor 3 between the terminals 8 are substantially the same, so that the resistance can be made the same.

  A multilayer wiring board having such an insulating substrate 1 and a pair of wiring conductors (first wiring conductor 2 and second wiring conductor 3) and first through conductor 4, second through conductor 5, and ground through conductor 6 is as follows. Produced by the method.

  For example, when the insulating layer is formed of an aluminum oxide sintered body, first, an appropriate organic binder and solvent are added to and mixed with raw material powders of aluminum oxide, silicon oxide, magnesium oxide and calcium oxide to form a slurry. At the same time, this is formed into a sheet shape by a doctor blade method or the like to produce a plurality of ceramic green sheets to be an insulating layer.

Next, through holes are formed by appropriate punching at predetermined positions where the first through conductor 4 and the second through conductor 5 and the ground through conductor 6 of the ceramic green sheet are formed, and the through hole is filled with a conductive paste. . Also, a conductor paste layer to be the first wiring conductor 2 and the second wiring conductor 3 is formed to a thickness of 10 μm to 20 μm at a predetermined position of the ceramic green sheet by a screen printing method or the like. The conductive paste is produced by kneading a metal powder having a high melting point such as tungsten (W), molybdenum (Mo), molybdenum-manganese (Mo-Mn) alloy, an appropriate resin binder, and a solvent.

  Finally, these ceramic green sheets are stacked and thermocompression bonded to produce a laminate, and the laminate is fired at a high temperature of about 1500 ° C. to 1600 ° C. to sinter the insulating layer, the wiring conductor, and the through conductor. An integrated multilayer wiring board is produced.

The ground conductor layer 7 is formed on one main surface and the other main surface of the insulating base 1, and the ground through conductor 6 is connected thereto. The thickness of the ground conductor layer 7 is not specifically defined, but is about 0.1 μm to 20 μm. When transmitting a signal having a high frequency of about 25 to 40 GHz, if the electrical resistivity of the ground conductor layer 7 is increased, the transmission characteristics may be deteriorated. Therefore, the electrical resistivity of the ground conductor layer 7 is 4 mΩ · cm or less. It is preferable that

  The ground conductor layer 7 is formed by printing and applying a conductor paste to be the ground conductor layer 7 on the upper surface of the first insulating layer 1a, and similarly to the conductor paste to be the ground conductor layer 7 on the entire lower surface of the third insulating layer 1c. Is formed by printing. The conductor paste to be the ground conductor layer 7 is manufactured by the same material and manufacturing method as the conductor paste to be the first wiring conductor 2 and the second wiring conductor 3 described above.

  The present invention is not limited to the above-described best mode, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the differential transmission line is formed by being connected from the terminal 8 on the upper surface of the insulating base 1 to the wiring inside the insulating base 1, and again connected to the terminal 8 on the upper surface. The terminal 8 may be connected to the internal wiring and may be connected to the terminal 8 on the lower surface, or vice versa, or the terminal 8 may be formed on the side surface. Further, for example, in the example of this embodiment, the insulating substrate 1 is made of ceramics, but the insulating substrate 1 may be formed of an insulating resin layer such as a polyimide layer, and the wiring conductor and the through conductor may be formed of copper. . In such a case, when the multilayer wiring board of the present invention is used for a multilayer wiring board for a probe card for checking the electrical characteristics of a semiconductor element by contacting probe pins, a plurality of wiring boards are formed on the upper surface of the multilayer wiring board. Since the insulating resin layers are laminated, the multilayer wiring board and the insulating resin layer are both organic resins, and the interface at the interface between the multilayer wiring board made of the insulating resin layer and the insulating resin layer can be improved.

DESCRIPTION OF SYMBOLS 1 ..... Insulation substrate 1a .... 1st insulation layer 1b .... 2nd insulation layer 1c .... 3rd insulation layer 2 .... First wiring conductor 2a... One wiring conductor 2b... First wiring conductor 3... Second wiring conductor 3a. One second wiring conductor 3b... The other second wiring conductor 4.... First through conductor 5.... Second through conductor 6..・ Grounding through conductor 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Grounding conductor layer 8 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Terminal

Claims (5)

In a differential transmission line composed of a pair of wiring conductors having a first wiring conductor and a second wiring conductor facing each other up and down across an insulating layer,
The first wiring conductor has one first wiring conductor and the other first wiring conductor;
The second wiring conductor has one second wiring conductor and the other second wiring conductor;
The one first wiring conductor and the one second wiring conductor are vertically opposed to each other with the insulating layer interposed therebetween, and the other first wiring conductor and the other second wiring conductor serve as the insulating layer. It is opposed to the top and bottom,
An end of the one first wiring conductor and an end of the other first wiring conductor are electrically connected via a first through conductor provided through the insulating layer;
An end of the one second wiring conductor and an end of the other second wiring conductor are electrically connected via a second through conductor provided through the insulating layer;
A differential transmission line, wherein a grounding through conductor is provided between the first through conductor and the second through conductor. The grounding through conductor bisects the center of the first through conductor and the center of the second through conductor on a straight line connecting the center of the first through conductor and the center of the second through conductor. The differential transmission line according to claim 1, wherein the differential transmission line is provided. A plurality of the ground through conductors are provided in a direction orthogonal to a straight line connecting the center of the first through conductor and the center of the second through conductor inside the first through conductor and the second through conductor. The differential transmission line according to claim 1, wherein the differential transmission line is characterized in that: 4. The differential transmission line according to claim 1, wherein a plurality of the ground through conductors are provided around the outside of the first through conductor and the second through conductor. 5. The differential transmission line according to any one of claims 1 to 4 is provided in an insulating base formed by laminating a plurality of insulating layers, and a ground conductor layer is provided on one main surface and the other main surface of the insulating base. And a grounding through conductor is connected to the grounding conductor layer.

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