JP4834937B2 - Multi-layer wiring board for high-frequency circuits - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiplayer wiring board for high frequency circuit wherein its high-frequency wirings are laid easily, and the unnecessary electromagnetic couplings of its transmission lines to each other are reduced. SOLUTION: In the multiplayer wiring board for high frequency circuit having the transmission lines of strip-line structures which includes a plurality of signal layers between two grounding-conductor layers 20, signal lines 50 and grounding lines 10 are laid alternately with respect to each signal layer, and the signal and grounding lines 50, 10 are laid oppositely to each other with respect to the adjacent signal layers to each other, and further, the width of the grounding line 10 is made larger than the one of the opposite signal line 50 thereto.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer wiring board for high-frequency circuits, and more particularly to a multilayer wiring board for high-frequency circuits that achieves high-density wiring with little crosstalk.
[0002]
[Prior art]
As seen in the development of information equipment in recent years, particularly in mobile communications, the signal frequency has been increased and the frequency has been increased, the circuit has been highly integrated, and high-density wiring has been further advanced.
A high frequency circuit signal transmission line on a printed wiring board includes a microstrip line (FIG. 4: a dielectric layer on a grounding conductor layer and a bare signal line on the dielectric layer), a coplanar line (FIG. 5). : Stripped signal line and ground line on the dielectric layer), stripline (FIG. 6: signal line in the dielectric layer sandwiched between the ground conductor layers), etc. In order to prevent crosstalk between the lines, a microstrip line (FIG. 7) with a ground line or a strip line (FIG. 8) may be used. Furthermore, multilayer wiring boards in which a dielectric layer and a signal layer or a grounding conductor layer are laminated have become common for high-density wiring.
[0003]
[Problems to be solved by the invention]
However, the microstrip line and the coplanar line, which are basic transmission lines, have an open space (air), so that they are easily affected by electromagnetic waves from the outside, and there is a disadvantage that crosstalk between adjacent signal lines is large. Although the electrostatic coupling between the signal lines can be suppressed by arranging the ground lines between the signal lines, the wiring density of the signal lines is lowered by increasing the number of the ground lines.
Furthermore, the above-mentioned drawbacks are eliminated by adopting a stripline structure without an open space. However, when a multi-layer board structure is adopted for high-density wiring, a ground conductor layer is inserted for each signal layer, so that the multi-layer structure can be reduced. It becomes remarkable, the production cost increases, and it is against the request to make the substrate thinner. When the grounding conductor layer in the middle of the multilayer substrate is omitted, crosstalk between signal layers becomes a problem.
[0004]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multilayer wiring board for a high-frequency circuit that facilitates high-density wiring and reduces unnecessary electromagnetic coupling between transmission lines.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the multilayer wiring board for a high-frequency circuit of a stripline structure transmission line including a plurality of signal layers in which a signal line and a ground line are alternately wired between two ground conductor layers, the high- frequency circuit The signal lines and the ground lines of the signal layers adjacent to each other in the thickness direction of the multilayer wiring board for use are arranged to face each other in the thickness direction ,
A multilayer wiring board for a high-frequency circuit, comprising a microstrip line structure portion in which a dielectric layer and a signal line are provided in this order on at least one of the two ground line conductor layers .
[0006]
The invention according to claim 2 is the multilayer wiring board for a high frequency circuit according to claim 1, wherein the width of the ground line is wider than the width of the signal line opposed in the thickness direction .
[0008]
According to a third aspect of the present invention, there is provided a high frequency circuit for a high frequency circuit according to any one of the first and second aspects, further comprising a stripline structure having no ground wire inside the multilayer wiring board for the high frequency circuit. It is a multilayer wiring board.
[0009]
<Action>
In the first aspect of the present invention, the ground wire is arranged between the signal lines to suppress crosstalk, and the ground wire is also opposed to the signal line of the adjacent signal layer, thereby serving as the ground layer of the stripline structure. In addition, unnecessary multi-layering is suppressed and high-density wiring is possible. Furthermore, by providing the microstrip line structure portion outside, it is possible to provide a signal line through which a relatively low frequency signal can flow through the external signal line. A relatively low-frequency signal has little crosstalk even if it flows through the signal line of the microstrip line structure portion.
Furthermore, in the structure of Claim 2, since the said ground line is wider than the width | variety of the signal line which opposes, the crosstalk between signal lines is further reduced.
Furthermore, the invention according to claim 3 has a stripline structure part which does not have a ground wire inside. A low-frequency signal or the like can flow through the signal line in the stripline structure, and in this case, since the frequency is low, there is little crosstalk.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the thickness, material, and dielectric constant of the dielectric are arbitrary, and the length and thickness of the signal line and the ground line, the interval between the signal lines, the number, and the material forming these are also arbitrary. . Furthermore, the size and thickness of the ground conductor layer and the material of the metal forming it are also arbitrary. Note that the signal layer is a layer including a signal line.
[0011]
Further, as shown in FIG. 2, a microstrip line structure 60 can be provided on the high-frequency circuit wiring board in order to enable a substrate having a different line form for each layer.
Furthermore, as shown in FIG. 3, an embodiment in which a partially different wiring structure is provided can be taken. FIG. 3 shows an example of an embodiment provided with a stripline structure 70 in which the ground wire 10 is eliminated when there is no concern about crosstalk.
[0012]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
< Reference example >
FIG. 1 shows a cross section showing a reference example of a multilayer wiring board for a high-frequency circuit according to the present invention.
In the multilayer wiring board for a high frequency circuit of this example, as shown in FIG. 1, grounding conductor layers 20 are provided on both surfaces of a dielectric layer 30 serving as a base, and the ground lines 10 and the signal lines 50 are alternately arranged. This is a multilayer wiring board for a high-frequency circuit of a stripline structure transmission line including two signal layers 20.
Next, the function of the multilayer wiring board for high-frequency circuits in this example (FIG. 1) will be described. With the signal line 52, crosstalk between the signal line 51 and the signal line 53 is suppressed by the ground line 11 and the ground line 13. Furthermore, the signal line 52 has a stripline configuration due to the grounding wire 12 and the grounding conductor layer 20, and the influence of external electromagnetic waves and interlayer crosstalk is suppressed.
All the ground lines use both the function of the coplanar and the function of the conductor layer for grounding of the strip line, and the number of layers is smaller than that of a simple strip line laminated structure.
[0013]
<Example 1 >
Figure 2 shows an embodiment of a cross section of a multilayer wiring board for a high frequency circuit according to the present invention. In this embodiment, the width of the ground line 10 is made wider than that of the signal line 50, so that it is closer to the stripline structure and the influence of interlayer crosstalk is reduced. Furthermore, the microstrip line structure portion 60 is formed in the lowermost layer, and a substrate having a different line form for each layer is made possible.
[0014]
<Example 2 >
FIG. 3 also shows a cross section of an embodiment of another multilayer wiring board for a high-frequency circuit according to the present invention. In this example, three signal layers 40 are inserted between the grounding conductor layers 20. Instead of the grounding conductor layer 20, a stripline structure was realized using only the grounding wire 10. Further, it was shown that when there is no concern about crosstalk, the ground wire 10 can be eliminated as in the stripline structure portion 70 and a partially different wiring structure can be set.
[0015]
Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to these embodiments. Any design differences that do not depart from the gist of the invention are also included in the invention.
[0016]
【The invention's effect】
As described above, according to the multilayer wiring board for a high-frequency circuit according to the present invention, high-density wiring can be realized while suppressing the influence of crosstalk between signal lines and external electromagnetic noise.
In addition, by providing a microstrip line structure portion outside, a signal line for flowing a signal with little crosstalk or the like can be provided.
Further, it can take the form of a stripline structure part that does not include a ground line inside, and a signal with little crosstalk can be passed through the signal line of the internal stripline structure part.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a reference example of a multilayer wiring board for a high-frequency circuit according to the present invention.
FIG. 2 is a cross-sectional view showing an embodiment of a multilayer wiring board for a high-frequency circuit according to the present invention.
FIG. 3 is a cross-sectional view showing an embodiment of a multilayer wiring board for a high-frequency circuit according to the present invention.
FIG. 4 is a cross-sectional structure diagram showing a layer structure of a conventional microstrip line.
FIG. 5 is a cross-sectional structure diagram showing a layer structure of a conventional coplanar line.
FIG. 6 is a cross-sectional structure diagram showing a layer structure of a conventional strip line.
FIG. 7 is a cross-sectional structure diagram showing a layer structure of a conventional microstrip line with a ground wire.
FIG. 8 is a cross-sectional structure diagram showing a layer structure of a conventional strip line with a ground wire.

Claims (3)

In the multilayer wiring board for a high frequency circuit of a stripline structure transmission line including a plurality of signal layers in which signal lines and ground lines are alternately wired between two ground conductor layers, the thickness direction of the multilayer wiring board for the high frequency circuit The signal line and the ground line of the signal layer adjacent to each other are arranged to face each other in the thickness direction ,
A multilayer wiring board for a high-frequency circuit, comprising a microstrip line structure portion in which a dielectric layer and a signal line are provided in this order on at least one of the two ground line conductor layers . 2. The multilayer wiring board for a high frequency circuit according to claim 1, wherein a width of the ground line is wider than a width of the signal line opposed in the thickness direction . The multilayer wiring board for a high frequency circuit according to any one of claims 1 to 2 , further comprising a stripline structure portion having no ground line inside the multilayer wiring board for a high frequency circuit.

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