JP2011165910A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board using a differential signal transmission circuit, the wiring board adjusting a skew of transmission line without damaging the signal quality of a transmission signal even in a high frequency region. <P>SOLUTION: The wiring board BP has: a semiconductor plane 30; a dielectric layer 40 laminated on the semiconductor plane 30; a pair of differential microstrip lines 100 which performs differential signal transmission in a predetermined region on the dielectric layer 40; and a plurality of skew adjustment sections 200 which perform skew adjustment in the differential microstrip lines 100. Each skew adjustment via 200 individually has: a semiconductor beer 201 which penetrates the dielectric layer 40 and connects to the semiconductor plane 30; and a circular land 202 which connects to the semiconductor via 201 at a peripheral edge of the semiconductor via 201, and is formed on the dielectric layer. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a wiring board such as a printed circuit board, and more particularly to a high-frequency wiring board provided with a differential transmission line that requires adjustment of signal propagation time.

  2. Description of the Related Art In recent years, with the demand for high-speed data transmission, the drive frequency has been increased or the bus width connecting each circuit has been increased. On the other hand, the increase in the driving frequency and the widening of the bus width cause generation of unnecessary radiation noise or deterioration of a signal transmitted due to external noise. Therefore, a pair of microstrip lines (hereinafter referred to as “differential microstrip line” or “coupled microstrip line”) whose transmission lines are close to each other from the viewpoint of high-speed data, suppression of unnecessary radiation noise, and resistance to external noise. A differential signal transmission system using a strip line) is often used.

  A differential signal transmission system using a differential microstrip line uses a differential driver such as an integrated circuit (IC: Integrated Circuit). By this differential driver, a differential signal is passed through the pair of differential microstrip lines (the phase is 180 degrees different) and a single signal is transmitted. Therefore, this differential signal transmission method can cancel out the magnetic field generated by each signal transmitted by each line, and therefore radiates compared to the single-ended transmission method in which data is transmitted by one signal line. Noise can be reduced. In addition, this differential signal transmission method synthesizes the voltage amplitude level of the transmission signal transmitted by each transmission line at the receiving side, as represented by low voltage differential signal transmission (LVDS: Low Voltage Differential Signaling). Therefore, the voltage amplitude level of each transmission signal can be further reduced.

  On the other hand, in this differential signal transmission method, in order for each circuit connected to the differential microstrip line to operate normally, a difference in signal propagation time (transmission time) of each line in the pair of differential microstrip lines ( It is necessary to transmit each transmission signal without generating (skew). That is, in this differential signal transmission method, it is necessary to match each signal propagation time of each pair of differential microstrip lines due to its characteristics, so that one pair of differentials such as a meander shape is used. The transmission line is wired on the wiring board by equal-length wiring that matches the line lengths of the microstrip lines.

  However, a wiring board in which a pair of transmission lines are wired by such an equal length wiring has many problems such as deterioration of transmission characteristics or fluctuation of delay time in a meander-shaped wiring portion, and in particular, transmission When the signal to be processed is further increased in speed, it becomes difficult to reduce the skew by using the equal length wiring.

  Therefore, as a solution to this, a wiring board that matches the signal delay time in each line by increasing the electrical length of a specific wiring is known. As an example, as shown in FIG. A dielectric 12 having a relative dielectric constant different from that of the substrate in a plan view is disposed in a bent portion 11 of a pair of transmission lines (hereinafter referred to as “differential transmission lines”) 10, which is caused by a difference in line length between the bent portions. A wiring board 1 in which the generated skew is adjusted has been proposed (Patent Document 1).

JP 2008-10673 A

  However, recently, with the increase in signal transmission speed and wiring density, the wiring pitch on the wiring board has become very small. For example, when the wiring board described in Patent Document 1 is used. Since the pair of transmission lines that transmit differential signals are strongly coupled, the change in relative permittivity around the transmission lines has a significant effect on the propagation speed of the transmission signals transmitted through each transmission line. It may be difficult to adjust the skew in a small and wide band.

  In addition, in such a wiring board, when the length of the dielectric constant adjusting portion such as a bent portion is a length that cannot be ignored with respect to the effective wavelength of the target frequency, resonance occurs in the dielectric constant adjusting portion. May occur and the signal characteristics of the transmission signal may deteriorate.

  Furthermore, when manufacturing such a wiring board, it is necessary to provide a material having a relative dielectric constant different from that of the substrate material in a dielectric constant adjusting portion such as a bent portion, which complicates the substrate manufacturing process, and Manufacturing cost increases.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a wiring board using a differential transmission system, in a transmission line skew without impairing the signal quality of the transmission signal even in a high frequency region. An object of the present invention is to provide a wiring board capable of adjusting the frequency to a wide band.

  (1) In order to solve the above problems, the present invention provides a conductor plane and a pair of differential signal transmission lines that perform differential signal transmission provided on the conductor plane, the first transmission line, A second transmission line provided adjacent to the first transmission line and having an electrical length shorter than that of the first transmission line; a pair of differential signal transmission lines formed from the second transmission line; One or more conductor vias formed close to the two transmission lines, and the closest distance between the conductor vias and the second transmission line is between the first transmission line and the second transmission line. The structure is shorter than the distance.

  (2) The present invention further includes a base material, wherein the differential transmission line is a differential microstrip line provided on one surface of the base material, and the one or more conductor vias are It has the structure currently formed on the one surface of the said base material near the said 2nd transmission line rather than the said 1st transmission line.

  (3) Moreover, this invention has the structure by which the number of the said conductor vias formed based on the electrical length of a said 1st transmission line and a 2nd transmission line is defined.

  (4) The present invention further includes a land provided at a peripheral edge of each conductor via and connected to each conductor via, and the land extends substantially in parallel along the second transmission line. It has the structure currently formed.

  (5) Moreover, this invention has the structure by which each said conductor via is formed in the center part of the said land.

  (6) Moreover, this invention has the structure by which each said conductor via is formed in the edge part of the said land.

  (7) Moreover, this invention has the structure by which the said each via | veer is formed in each said land.

  (8) Further, according to the present invention, the pair of differential signal transmission lines includes a straight portion and a bent portion, and the conductor via is formed close to the bent portion of the second transmission line. It has the composition which is.

  According to the present invention, the capacitive component can be formed by the second transmission line and the conductor via, and the closest distance between the conductor via and the second transmission line is made larger than the distance between the first transmission line and the second transmission line. Since the dielectric constant for the second transmission line can be adjusted based on the capacitance component formed by shortening, the skew due to the line length difference of each transmission line can be adjusted in a wide band, and the conductor via Since the skew adjustment can be performed by forming, it can be easily realized by an existing substrate manufacturing process.

It is the upper side figure and enlarged view of 1st Embodiment of the wiring board which concerns on this invention. FIG. 2 is a cross-sectional view taken along the line X-X ′ in FIG. 1 in the wiring board according to the first embodiment. It is an enlarged view of the bending part of a differential microstrip line. It is a graph which shows the phase characteristic of the transmission signal transmitted in the differential microstrip line | wire when skew adjustment is not carried out. It is a graph which shows the phase characteristic of the transmission signal which transmits the inside of the differential microstrip line in 1st Embodiment. It is a graph which shows the delay frequency characteristic of the propagation time in the 2nd transmission line in the differential microstrip line (non-measurement line) at the time of skew adjustment not being performed, and the differential microstrip line of a 1st embodiment. It is a graph which shows the variation | change_quantity of the electrical length of a differential microstrip line with respect to the number of vias of the skew adjustment part in 1st Embodiment. It is a graph which shows the characteristic of the insertion loss in the differential microstrip line (non-measurement line) when skew adjustment is not carried out, and the differential microstrip line of a 1st embodiment. It is the upper side figure and enlarged view of 2nd Embodiment of the wiring board which concerns on this invention. It is a top view of 3rd Embodiment of the wiring board which concerns on this invention. It is a top view of 4th Embodiment of the wiring board which concerns on this invention. 10 is a top view of a wiring board according to Patent Document 1. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment described below, the wiring board of the present invention is applied to a high-frequency wiring board (hereinafter simply referred to as “wiring board”) in which a pair of differential microstrip lines 100 are disposed. It is an embodiment.

<First Embodiment>
First, a first embodiment of a wiring board BP according to the present invention will be described with reference to FIGS.

  First, the structure of the wiring board BP of the present embodiment will be described with reference to FIGS. 1 is a top view and an enlarged view of the wiring board BP in the present embodiment, and FIG. 2 is a cross-sectional view taken along line X-X ′ in FIG. 1 in the wiring board BP in the present embodiment.

  As shown in FIGS. 1 and 2, the wiring board BP of this embodiment is formed in a conductor plane 30, a dielectric layer 40 laminated on the conductor plane 30, and a predetermined region on the dielectric layer 40. And a pair of differential microstrip lines 100 that perform differential signal transmission. In addition, the wiring board BP includes a plurality of skew adjustment units 200 that perform skew adjustment in the differential microstrip line 100.

  The differential microstrip line 100 is juxtaposed with a first transmission line 100A and a wiring pitch (hereinafter also referred to as “line spacing” or “inter-line distance”) S predetermined for the first transmission line 100A. The portion bent at a right angle is formed from the second transmission line 100B disposed inside the first transmission line 100A. The differential microstrip line 100 includes a vertical extending portion 110 extending in a first direction (horizontal direction in FIG. 1), and a second direction (horizontal in FIG. 1) perpendicular to the direction in which the vertical extending portion 110 extends. Horizontal extending portion 120 extending in the direction). In addition, the differential microstrip line 100 includes a bent portion 130 that is integrally formed between the vertically extending portion 110 and the horizontally extending portion 120.

  In the following description, the vertically extending portions 110 in the first transmission line 100A and the second transmission line 100B are referred to as a first vertical straight portion 110A and a second vertical straight portion 110B, respectively. Further, the horizontally extended portions 120 in the first transmission line 100A and the second transmission line 100B are referred to as a first horizontal straight line portion 120A and a second horizontal straight line portion 120B, respectively. Further, the bent portions 130 in the first transmission line 100A and the second transmission line 100B are referred to as a first bent portion 130A and a second bent portion 130B, respectively.

  Each skew adjustment unit 200 is arranged on the dielectric layer 40 along the second transmission line 100B and closer to the second transmission line 100B than the first transmission line 100A. That is, each skew adjustment unit 200 is on the side opposite to the side on which the first transmission line 100A arranged in parallel with the second transmission line 100B is disposed, with the second transmission line 100B as a reference. It is formed in the vicinity of the transmission line 100B along the second vertical straight portion 110B, the second bent portion 130B, and the second horizontal straight portion 120B.

  Each skew adjustment unit 200 includes a conductor via 201 that penetrates the dielectric layer 40 and is connected to the conductor plane 30, and a conductor layer 201 connected to the conductor via 201 at the periphery of the conductor via 201. And a circular land 202 (hereinafter referred to as “circular land”) 202 formed thereon.

  Next, details of the skew adjustment unit 200 of the present embodiment will be described with reference to FIGS. 1 and 3 described above. FIG. 3 is an enlarged view of a bent portion of the differential microstrip line.

  Normally, at the bent part of the differential microstrip line, the bent part of one transmission line is longer than the bent part of the other transmission line, so the electric length at the bent part of one transmission line is the transmission length of the other transmission line. It becomes longer than the bent part of the track. Therefore, a skew is generated between the differential signals transmitted by the transmission lines due to the difference in the line length. That is, the arrival time of the transmission signal transmitted through one transmission line is shifted from the transmission signal transmitted through the other transmission line.

  For example, as shown in FIG. 3, in a general wiring board, when the bent portion of the differential microstrip line is provided at 45 degrees with respect to each of the vertically extending portion and the horizontally extending portion, The total 4α of the line length difference α between the transmission line formed in the transmission line and the transmission line formed inside is the value shown in (Equation 1). W represents the wiring width of each transmission line, and S represents the wiring pitch.

  Therefore, the shorter the wiring width W and wiring pitch S of each transmission line, the smaller the skew generated at each bent portion. When the wiring pitch S is narrow (in the case of a narrow pitch), the skew is generated at each bent portion. The skew to be done is not so large

  However, when wiring is performed at high speed and high density on the wiring board, the wiring route between the differential drivers connected to the IC chip and other differential microstrip lines has many bent portions, and the skew Accumulate so much that it cannot be ignored. In other words, the total skew becomes a non-negligible magnitude relative to the skew generated in the differential driver itself (the entire differential microstrip line between the circuits). This will degrade the motion signal.

  On the other hand, if the inductance of the unit section of the transmission line is “L [H / m]” and the capacitance (capacitance component) of the transmission line is “C [F / m]”, the delay time “T [ s / m] ”can be expressed by (Formula 2). Therefore, when the plurality of skew adjusting units 200 including the conductor via 201 and the circular land 202 are provided as in the present embodiment, the second transmission line 100B of the differential microstrip line 100, each conductor via 201, and the second By increasing the capacitance component between the transmission line 100B and each circular land 202, the propagation time of the signal transmitted through the second transmission line 100B can be delayed.

  In the present embodiment, even when a large number of bent portions 130 are formed on the wiring board BP, the skew of each bent portion 130 accumulates, and signal delay in the entire differential microstrip line 100 is not generated. In addition, a plurality of skew adjustment units 200 are provided. That is, in this embodiment, in order to adjust the skew of the transmission line by delaying the propagation time of the signal transmitted through the second transmission line 100B for each bent portion 130, the first transmission line 100A and the second transmission line 100B. A plurality of skew adjusting units 200 are provided so that the propagation times of the signals transmitting the signals coincide with each other.

  Specifically, each skew adjustment unit 200 according to the present embodiment includes the conductor via 201 and the circular land 202 formed on the dielectric layer by bonding to the conductor via 201 as described above. The closest distance L1 between each conductor via 201 and the second transmission line 100B is arranged to be shorter than the wiring pitch S between the first transmission line 100A and the second transmission line 100B.

  The larger the capacitance component between the second transmission line 100B of the differential microstrip line 100 and the skew adjustment unit 200 with respect to the capacitance component between the edge couplings of the differential microstrip line 100, the greater the capacitance of the second transmission line 100B. Propagation time delay increases. When the closest distance L1 between the skew adjustment unit 200 and the second transmission line 100B is longer than the wiring pitch S, the edge coupling is dominant, so that the delay due to the arrangement of the skew adjustment unit 200 is very small. It is difficult to obtain the skew adjustment effect.

  In the present embodiment, as shown in FIG. 1, the 21 regularly arranged skew adjustment units 200 include the second bent portion 130B and the second vertical straight portion 110B to the second horizontal straight portion. 120B is provided along the second transmission line 100B.

  As described above, the bent portion 130 in the differential microstrip line 100 according to the present embodiment, that is, the first bent portion 130A of the first transmission line 100A and the second bent portion 130B of the second transmission line 100B have a right-angle shape. And has a predetermined oblique angle (for example, 45 degrees). However, since the amount of generated skew is hardly changed compared to the case of the oblique angle as in the present embodiment, the shape of the bent portion 130 in the differential microstrip line 100 may be a right angle or an arc. Also good.

  In each skew adjustment unit 200, the wiring pitch S of the conductor vias 201, that is, the distance between one conductor via 201 and another conductor via 201 is determined when transmitting a predetermined signal to the differential microstrip line 100. It is preferably “λ / 10” or less with respect to the effective wavelength (λ) of the frequency used.

  Next, examples of the present embodiment will be described with reference to FIGS. This example is the result of a three-dimensional electromagnetic field analysis using specific structural parameters. FIG. 4 shows the phase characteristics of signals transmitted through each transmission line when no countermeasure against skew is taken, and FIG. 5 shows the signals transmitted through the first transmission line 100A and the second transmission line 100B in this embodiment. The phase characteristics are shown. FIG. 6 shows a delay in propagation time (hereinafter, referred to as “transmission time”) between the differential microstrip line (non-measurement line) and the differential transmission line 100B in the differential microstrip line 100 of the first embodiment when the skew is not adjusted. 7 is a graph showing the frequency characteristic of the differential microstrip line 100 with respect to the number of vias of the skew adjustment unit 200 in the first embodiment. It is. Further, FIG. 8 shows insertion loss characteristics Sdd21 in the differential microstrip line (non-measurement line) and the differential microstrip line of the first embodiment when the skew is not adjusted.

  In the structural parameters used in this analysis, the wiring width (W) of the first transmission line 100A and the second transmission line 100B in the differential microstrip line 100 is “100 μm”, the pitch interval (S) is “80 μm”, and the wiring board The substrate thickness of BP is “150 μm” and the relative dielectric constant (εr) is “4.9”.

  Further, the dielectric substrate used in this analysis is assumed to be FR-4. This “FR” is an index indicating the flame retardancy of the copper-clad laminate that is a member of the printed wiring board BP, and “FR-1”, which has the lowest flame retardancy, has the highest flame retardancy, “FR”. Each grade up to "-6" is shown. “FR-4” is a copper-clad laminate having a general heat resistance using a flame-retardant glass cloth base epoxy resin.

  At this time, the line length difference between the bent portion of the first transmission line 100A and the bent portion of the second transmission line 100B is “298 μm” from the above (Equation 1), and the total length of each transmission line is The transmission line 100A is “about 6563 μm” and the second transmission line 100B is “about 6265 μm”. Further, the via diameter of each conductor via 201 is “80 μm”, the land diameter thereof is “90 μm”, the interval (L2) between each conductor via 201 is “150 μm”, and the distance from the second transmission line 100B to each conductor via 201 ( L1) is “40 μm”.

  According to FIG. 4, it can be seen that in the line length difference (298 μm) in each transmission line, a phase difference of about 100 degrees is generated in the signal transmitted through each transmission line at 70 GHz.

  On the other hand, according to FIG. 5, as described above, the propagation time of the second transmission line 100B is lengthened (that is, the signal transmitted through the second transmission line 100B is delayed). It can be seen that there is no phase difference between signals transmitted through the transmission line 100A and the second transmission line 100B.

  Further, according to FIG. 6, the propagation delay time in the second transmission line 100 </ b> B when the propagation frequency is 70 GHz on the wiring board that does not take countermeasures against skew, that is, the non-measurement line and the wiring board BP of the present embodiment is “ 1.2 picoseconds "has been shortened. That is, since the product of the delay amount and the speed of light is the electrical length, the portable wiring board BP of this embodiment has an adjustment effect of “360 μm” in terms of the electrical length.

  On the other hand, in order to adjust the desired skew amount, the number of skew adjusting units 200 to be installed may be adjusted. According to FIG. 7, the electrical length change amount increases almost linearly as the number of via adjustment units 200 increases, and there is a skew adjustment effect of “about 11 μm” in the electrical length per one of the skew adjustment units 200. I understand that.

  Further, according to FIG. 8, the insertion loss of the wiring board BP of this embodiment is improved by about 0.6 dB over the non-measured wiring board when the insertion loss is 70 GHz. This is because the signal component converted from the differential-differential mode (Sdd21) to the differential-common mode (Scd21) is reduced by the phase adjustment.

  As described above, in the structure of this embodiment, the delay time can be easily adjusted not only at the input / output ends of the signal but also within the transmission line. Talk or noise emission can be reduced.

  As described above, the wiring board BP of the present embodiment can form a capacitive component by the second transmission line 100B and the conductor via 201, and set the closest distance between the conductor via 201 and the second transmission line 100B to the first transmission line. The dielectric constant for the second transmission line 100B can be adjusted based on the capacitance component formed by shortening the distance between the lines of 100A and the second transmission line 100B. Therefore, the wiring board BP of this embodiment can adjust the skew caused by the line length difference between the transmission lines in a wide band. In addition, since the wiring board BP of the present embodiment can perform skew adjustment by forming the conductor via 201, it can be easily realized by an existing board manufacturing process.

  In the present embodiment, the wiring board BP having the skew adjustment unit 200 has been described. However, the present invention is not limited to this embodiment, and a pair of differential signal transmission lines, such as a differential signal transmission line, is not limited to this embodiment. What is necessary is just to transmit a signal with a track | line.

  In the present embodiment, the skew adjusting unit 200 is arranged around the bent portion 130 of the differential microstrip line 100. However, the skew adjusting unit 200 is not limited to this portion, and is arranged along the transmission line in which the skew is generated. It only has to be.

<Second Embodiment>
Next, a second embodiment of the wiring board BP according to the present invention will be described with reference to FIG. FIG. 9 is a top view and an enlarged view of the wiring board BP in the present embodiment.

  In the present embodiment, instead of the plurality of skew adjustment units 210 having the circular lands 202 and the conductor vias 201 in the first embodiment, an oval (elliptical) land (hereinafter referred to as an “oval land”) 212 and The present invention is characterized in that it has a plurality of skew adjusting portions 210 including conductor vias 201 provided at the center of the oval land 212. Other configurations are the same as those of the first embodiment, and the same members as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  First, the structure of the wiring board BP of this embodiment will be described with reference to FIG.

  Each skew adjustment unit 210 of the present embodiment includes an oval land 212 extending in an oval shape along the second transmission line 100 </ b> B, and a conductor via 201 provided in the center of the oval land 212. Yes.

  Further, in the present embodiment, as shown in FIG. 9, ten regularly arranged skew adjustment units 210 include the second bent portion 130B and the second vertical straight portion 110B to the second horizontal straight portion 120B. Until the second transmission line 100B.

  Each of the oval lands 212 is shorter than the interval between the conductor vias 201 of each skew adjustment unit 210, and is not connected (joined) to the conductor vias 201 formed in the other adjacent oval lands 212, but independently. Is formed. Further, the length (L3) in the longitudinal direction of each oval land 212 is desirably “λ / 10” or less with respect to the effective wavelength (λ) of the target frequency.

  In the present embodiment, a capacitive component is formed by the second transmission line 100B and the oval land 212, that is, between the second transmission line 100B and the oval land 212. Accordingly, the delay time per skew adjusting unit 210 is larger than that in the first embodiment, and the skew can be adjusted with a smaller number. Therefore, the via interval (L2) is arranged narrowly depending on the substrate process or mounting situation. It is effective when it is not possible.

  In addition, about the Example of the three-dimensional electromagnetic field analysis in this embodiment, the result similar to 1st Embodiment can be obtained (refer FIG. 5). As specific structural parameters, the via diameter of the conductor via 201 is “80 μm”, the land diameter “90 μm” and the length “300 μm” of the oval land 212, and the via interval (L2) of the conductor via 201 is “300 μm”. " The distance (L1) from the second transmission line 100B to the conductor via 201 is “40 μm”, and other structural parameters are the same as those in the first embodiment.

  As described above, in addition to the effects of the first embodiment, the wiring board BP of the present embodiment can change the relative dielectric constant with respect to the second transmission line 100B not only by the conductor via 201 but also by the land shape. Therefore, the wiring board BP of the present embodiment can adjust the skew even when the interval between the conductor vias 201 cannot be narrowly arranged due to various processes in the substrate process or various mounting conditions, and each transmission line It is possible to adjust the skew caused by the difference in line length in a wide band.

  In the present embodiment, the wiring board BP having the skew adjustment unit 210 has been described as in the first embodiment. However, the present invention is not limited to this embodiment, and is not a differential microstrip line. What is necessary is just to transmit a signal by a pair of lines, such as a dynamic signal transmission line.

  Further, in the present embodiment, as in the first embodiment, the skew adjustment unit 210 is arranged around the bent portion 130 of the differential microstrip line 100. However, the present invention is not limited to this portion, and skew is generated. What is necessary is just to be distribute | arranged along the transmission line to do.

<Third Embodiment>
Next, a third embodiment of the wiring board BP according to the present invention will be described with reference to FIG. FIG. 10 is a top view of the wiring board BP in the present embodiment.

  This embodiment is characterized in that the conductor via 201 is provided at one end of the oval land 222 instead of being provided at the center of the oval land 222 in the second embodiment. Other configurations are the same as those of the second embodiment, and the same members as those of the second embodiment are denoted by the same reference numerals and description thereof is omitted. Hereinafter, the structure of the wiring board BP of the present embodiment will be described with reference to FIG.

  Each skew adjustment unit 220 of the present embodiment includes an oval land 222 extending in an oval shape along the second transmission line 100B, and a conductor via 201 provided at one end of the oval land 222. Yes.

  In the present embodiment, as shown in FIG. 10, ten regularly arranged skew adjusting units 220 include the second bent portion 130B and the second vertical straight portion 110B to the second horizontal straight portion 120B. Until the second transmission line 100B.

  Each of the oval lands 222 is shorter than the interval between the conductor vias 201 of each skew adjustment unit 220, and is not connected (joined) to the conductor vias 201 formed in the other adjacent oval lands 222. Is formed. In addition, the length (L3) in the longitudinal direction of each oval land 222 is desirably “λ / 10” or less with respect to the effective wavelength (λ) of the target frequency.

  In the present embodiment, as in the second embodiment, a capacitive component is formed by the second transmission line 100B and the oval land 222, that is, between the second transmission line 100B and the oval land 222. It has become. Therefore, the delay time per one skew adjusting unit 220 is larger than that in the first embodiment, and the skew can be adjusted with a smaller number. Therefore, the via interval L2 cannot be narrowly arranged depending on the substrate process and the mounting situation. It is effective in the case.

  As described above, the wiring board BP of the present embodiment can change the relative dielectric constant with respect to the second transmission line 100B not only by the conductor via 201 but also by the land shape, similarly to the effect of the second embodiment. Therefore, the wiring board BP of the present embodiment can adjust the skew even when the interval between the conductor vias 201 cannot be narrowly arranged due to various processes in the substrate process or various mounting conditions, and each transmission line It is possible to adjust the skew caused by the difference in line length in a wide band.

  In the present embodiment, the wiring board BP having the skew adjustment unit 220 has been described as in the second embodiment. However, the present invention is not limited to this embodiment, and there is no differential microstrip line. What is necessary is just to transmit a signal by a pair of lines, such as a signal transmission line.

  Further, in the present embodiment, as in the second embodiment, the skew adjusting unit 220 is arranged around the bent portion 130 of the differential microstrip line 100. However, the present invention is not limited to this portion, and skew is generated. What is necessary is just to be distribute | arranged along the transmission line to do.

<Fourth embodiment>
Next, a fourth embodiment of the wiring board BP according to the present invention will be described with reference to FIG. FIG. 11 is a top view of the wiring board BP in the present embodiment.

  In this embodiment, in each skew adjustment unit 230 of the third embodiment, the conductor via 201 is provided at both ends of the oval land 222 instead of the point that the conductor via 201 is provided at one end of the oval land 222. It is characterized in that it is provided. Other configurations are the same as those of the third embodiment, and the same members as those of the third embodiment are denoted by the same reference numerals and description thereof is omitted. Hereinafter, the structure of the wiring board BP of the present embodiment will be described with reference to FIG.

  Each skew adjustment unit 230 of the present embodiment includes an oval land 222 extending in an oval shape along the second transmission line 100B, and first conductor vias 201 and second electrodes provided at both ends of the oval land 222. And a conductor via 201.

  Further, in the present embodiment, as shown in FIG. 11, ten regularly arranged skew adjustment units 230 include the second bent portion 130B and the second vertical straight portion 110B to the second horizontal straight portion 120B. Until the second transmission line 100B.

  Each of the oval lands 222 is shorter than the interval between the conductor vias 201 of each skew adjusting unit 230, and is not connected (joined) to the conductor vias 201 formed in the other adjacent oval lands 222. Is formed. Further, the length L3 in the longitudinal direction of each oval land 222 is preferably “λ / 10” or less with respect to the effective wavelength (λ) of the target frequency.

  In the present embodiment, a capacitive component is formed by the second transmission line 100B and the oval land 222, that is, between the second transmission line 100B and the oval land 222. Therefore, since the delay time per one skew adjusting unit 230 is larger than that in the first embodiment and the skew can be adjusted with a smaller number, the via interval L2 cannot be narrowly arranged depending on the substrate process and the mounting situation. It is effective in the case.

  As described above, the wiring board BP of the present embodiment can change the relative dielectric constant with respect to the second transmission line 100B not only by the conductor via 201 but also by the land shape, similarly to the effect of the third embodiment. Therefore, the wiring board BP of the present embodiment can adjust the skew even when the interval between the conductor vias 201 cannot be narrowly arranged due to various processes in the substrate process or various mounting conditions, and each transmission line It is possible to adjust the skew caused by the difference in line length in a wide band.

  In the present embodiment, as in the third embodiment, the high-frequency wiring board BP having the skew adjustment unit 230 has been described. However, the present invention is not limited to this embodiment, and a differential microstrip line is used. However, any device that transmits a signal through a pair of lines such as a differential signal transmission line may be used.

  Further, in the present embodiment, as in the third embodiment, the skew adjusting unit 230 is arranged around the bent portion 130 of the differential microstrip line 100. However, the present invention is not limited to this portion, and skew is generated. What is necessary is just to be distribute | arranged along the transmission line to do.

DESCRIPTION OF SYMBOLS 100 ... Microstrip line 100A ... 1st transmission line 100B ... 2nd transmission line 110 ... Vertical extension part 110A ... 1st vertical linear part 110B ... 2nd vertical linear part 120 ... Horizontal extension part 120A ... 1st horizontal linear part 120B ... Second horizontal straight portion 130 ... bent portion 130A ... first bent portion 130B ... second bent portion 200 ... skew adjusting portion 201 ... conductive via 202 ... circular lands 212, 222 ... oval lands

Claims (8)

A conductor plane;
A pair of differential signal transmission lines that perform differential signal transmission provided on the conductor plane, and are provided adjacent to the first transmission line and the first transmission line and more than the first transmission line. A second transmission line having a short electrical length; a pair of differential signal transmission lines formed from;
One or more conductor vias formed closer to the second transmission line than the first transmission line;
With
The wiring board, wherein a closest distance between the conductor via and the second transmission line is shorter than a distance between the first transmission line and the second transmission line. The wiring board according to claim 1,
It further has a substrate,
While the differential transmission line is a differential microstrip line provided on one surface of the substrate,
The wiring board in which the one or more conductor vias are formed on one surface of the base material closer to the second transmission line than the first transmission line. In the wiring board according to claim 1 or 2,
The wiring board in which the number of the conductor vias formed based on the electrical length of the first transmission line and the second transmission line is determined. In the wiring board as described in any one of Claims 1 thru | or 3,
A wiring board provided at a periphery of each conductor via and further including a land connected to each conductor via, wherein the land extends substantially in parallel along the second transmission line. The wiring board according to claim 4,
A wiring board in which each of the conductor vias is formed at the center of the land. The wiring board according to claim 4,
A wiring board in which each conductor via is formed at an end of the land. The wiring board according to any one of claims 4 to 6,
A wiring board in which a plurality of the conductor vias are formed in each land. In the wiring board as described in any one of Claims 1 thru | or 7,
The pair of differential signal transmission lines is composed of a straight portion and a bent portion,
The wiring board, wherein the conductor via is formed close to a bent portion of the second transmission line.

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