JPH0593080U - High speed signal circuit board - Google Patents

Abstract

(57) [Summary] [Object] To provide a circuit board for high-speed signals, which is excellent in transmission characteristics with less reflection of high-speed signals by adding a simple pattern to the circuit board. [Structure] A plurality of signal layers (s0 to s2) and GND layers (g1 to g3) are provided, and the thickness is controlled so that the conductors of the signal layers are impedance-matched between the signal layers and the GND layers. A multilayer circuit board having dielectric layers c1 to c6 formed by forming a VIA land around a VIA land 3a provided with a VIA 4 connecting between the signal lines 2a and 2b so as to surround the VIA land. And a structure having ground patterns 5a and 5b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circuit board, and more particularly to a high-speed signal circuit board that transmits high-speed signals through the circuit board.

[0002]

[Prior Art]

 8 to 10 are vertical cross-sectional views of a main part schematically showing three structural examples of a VIA (referred to as a via or via) portion of a conventional high-speed signal circuit board. 11 to 13 are horizontal sectional views taken along the lines AA, BB, and CC shown in FIGS. 8 to 10, respectively. Further, FIG. 14 is a top view taken along the line DD of FIG.

Here, the conventional example of FIG. 8 has ground / power supply layers (hereinafter referred to as GND layers) g1, g2, and g3, and a signal transmission line is provided on a signal layer s1 between the GND layer g1 and the GND layer g2. Signal line 2b is formed in the signal layer s2 between the GND layer g2 and the GND layer g3, and the signal line 2a and the signal line 2b are connected to the VIA lands 3a, 3b, The layers are connected via VIA4 through 3c. Further, the conventional example of FIG. 9 has GND layers g1 and g3, the signal layers s1 and s2 are provided between these GND layers, and the signal lines 2a and the signal layer s2 provided in the signal layer s1 are provided. The digitized signal line 2b is interlayer-connected by VIA 4 via VIA lands 3a and 3c. Further, the conventional example of FIG. 10 has a GND layer g2 and a GND layer g3, and signal layers s0 and s2 are provided above and below the GND layer g2, respectively, and formed on the signal line 2c and the signal layer s2 formed on the signal layer s0. The signal line 2b and the signal line 2b are interconnected via the VIA 4 via the VIA lands 3d, 3b and 3c.

In the conventional example shown in FIGS. 8 to 10, both the signal layer for transmitting a signal and the GND layer are formed of a conductor layer made of a conductor, but between the signal layer and the GND layer. The high-speed signal circuit board is configured by interposing dielectric layers c1 to c6 formed by controlling the thickness so that the conductors of the signal layer are impedance-matched. The GND lines 1a, 1b, 1c are line patterns formed on the GND layers g1, g2, g3, respectively.

Common to any of the conventional examples shown in FIGS. 8 to 10 as described above, the VIA 4 connecting the signal lines between layers penetrates through the conductor layer of the GND layer g 2 as in the case of FIGS. 8 and 10. When it is formed, as seen in FIG. 12, a GND pattern including the GND layer g2 is formed around the VIA land 3b. However, as shown in FIGS. 11, 13 and 14, the GND layers are not formed around the VIA lands 3a, 3c and 3d in the conductor layers of the signal lines 2a, 2b and 2c, respectively. Is used.

[0006]

[Problems to be solved by the device]

 In the conventional high-speed signal circuit board as described above, in the conductor layer of the signal transmission line, there is a phenomenon in which a part of the signal is reflected when there is a discontinuous portion such as VIA in the waveguide. There has been a problem in that the signal transmission characteristics are deteriorated near the outer periphery of the land, especially for high-speed signals, so that the signal transmission characteristics are deteriorated.

The present invention has been made in order to eliminate the above-mentioned problem that signal transmission occurs in the vicinity of the outer periphery of the VIA land in the conductor layer for signal transmission, which deteriorates the transmission characteristics of high-speed signals. Then, it is an object of the present invention to provide a structure of a circuit board for high-speed signals, which has excellent transmission characteristics of high-speed signals.

[0008]

[Means for Solving the Problems]

 A high-speed signal circuit board according to the present invention has a plurality of signal transmission conductor layers and a ground / power supply conductor layer, and a signal transmission layer is provided between the signal transmission conductor layer and the ground / power supply conductor layer. A circuit board having a dielectric layer formed by controlling the thickness so that the conductors of the conductor layer for signal transmission are impedance-matched, and a signal transmission conductor provided with a VIA for connecting two signal transmission conductor layers. The ground pattern is formed around the VIA land of the layer so as to surround the VIA land.

[0009]

[Action]

 In the present invention, the ground pattern is formed around the VIA land of the signal layer so as to surround the VIA land of the signal layer at the portion of the VIA that connects the signals between the signal layers. The reflection of high-speed signals that occurs when there is no ground pattern in the vicinity of the outer periphery is suppressed, and non-reflective transmission is promoted, so that the transmission characteristics of high-speed signals can be maintained at the desired excellent characteristics.

[0010]

【Example】

 FIG. 1 is a vertical sectional view of an essential part schematically showing a first embodiment according to the present invention. 4, 5 and 6 are horizontal sectional views taken along the lines AA, BB and CC shown in FIG. 1, respectively. In the explanatory views of the embodiments, the same or corresponding parts as those in the conventional example shown in FIGS. 8 to 14 are designated by the same reference numerals.

In FIGS. 1 and 4 to 6, between the signal layers s1 and s2 of the conductor layers for transmitting signals and the GND layers g1, g2 and g3 of the ground / power source conductor layers, the signal line 2a, A high-speed signal circuit board composed of a multi-layer board is formed with dielectric layers c1 to c6 whose thickness is controlled so that the impedance of 2b is matched. Therefore, the main configuration of this embodiment corresponds to the conventional example of FIG.

In this configuration, the signal line 2a of the signal layer s1 and the signal line 2b of the signal layer s2, which are arranged with the GND layer g2 in between, are provided to the VIA 4 via the VIA lands 3a, 3b, 3c. Are connected between layers. In this case, as shown in FIGS. 4 and 6, around the VIA lands 3a and 3c of the signal layers s1 and s2, ground patterns 5a and 5b, respectively, are formed so as to surround the VIA lands. There is. Note that, in FIG. 5, such a ground pattern is not particularly formed, and as illustrated in the conventional example of FIG. 12, the VIA 3b is widely surrounded by the GND layer g2. In this way, by providing the ground patterns 3a and 3c on the signal layers s1 and s2 so as to surround the VIA lands 3a and 3a, respectively, it is possible to suppress signal reflection near the outer circumferences of the VIAs 3a and 3c. It became so. For this reason, the transmission characteristics of high-speed signals in particular can be significantly improved over the conventional one.

FIG. 2 is a vertical cross-sectional view of a main part schematically showing a second embodiment of the present invention. As shown in the figure, this is an example in which two signal layers s1 and s2 exist between two GND layers g1 and g3. Therefore, the main configuration of this embodiment corresponds to the conventional example of FIG. The horizontal sectional views taken along the lines AA and CC of FIG. 2 are similar to those shown in FIGS. 4 and 6, respectively, and the same effects as those described in the first embodiment can be obtained. ..

Further, FIG. 3 is a vertical cross-sectional view of a main part schematically showing a third embodiment according to the present invention. As shown in the figure, the signal layer is present on the surface layer of the multi-layer substrate, and the main configuration thereof corresponds to the conventional example of FIG. FIG. 7 is a top view taken along the line D-D shown in FIG. As shown in FIG. 7, the signal layer s0 is provided with a ground pattern 5c so as to surround the VIA land 3d. With this ground pattern, the same effect as in the case of the first embodiment can be obtained together with the ground pattern 5b shown in FIG.

Needless to say, the shape of the ground pattern is not limited to the shape of the patterns shown in the embodiments of FIGS. 4, 6 and 7.

[0016]

[Effect of the device]

 As described above, according to the present invention, in a high-speed signal circuit board having a multi-layer structure of a signal layer and a GND layer, a signal layer that connects the signal lines of two different layers by VIA is provided around the VIA land. By providing a ground pattern to cover this, it is possible to reduce the signal reflection near the periphery of the VIA land. For this reason, an improvement in the transmission characteristics of high-speed signals has been achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an essential part schematically showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of an essential part showing a second embodiment according to the present invention.

FIG. 3 is a vertical sectional view of an essential part showing a third embodiment according to the present invention.

FIG. 4 is a horizontal sectional view taken along the line AA shown in FIG.

5 is a horizontal sectional view taken along the line BB shown in FIG.

6 is a horizontal sectional view taken along the line CC shown in FIG.

FIG. 7 is a top view taken along the line DD shown in FIG.

FIG. 8 is a vertical cross-sectional view of a main part schematically showing a conventional example of a high-speed signal circuit board.

FIG. 9 is a vertical cross-sectional view of a main part showing another conventional example of a high-speed signal circuit board.

FIG. 10 is a vertical sectional view of an essential part showing another conventional example of a high-speed signal circuit board.

FIG. 11 is a horizontal sectional view taken along the line AA shown in FIGS. 8 and 9.

FIG. 12 is a horizontal sectional view taken along the line BB shown in FIGS. 8 and 10.

FIG. 13 is a horizontal sectional view taken along the line CC shown in FIGS. 8, 9 and 10.

FIG. 14 is a top view taken along the line DD shown in FIG.

[Explanation of symbols]

1a, 1b, 1c GND line (ground / power supply line) 2a, 2b, 2c Signal line (signal transmission line) 3a, 3b, 3c, 3d VIA land 4 VIA 5a, 5b, 5c Ground pattern g1, g2, g3 GND layer (Ground / power supply layer) s0, s1, s2 signal layer c1, c2, c3, c4, c5, c6 dielectric layer

Claims (1)

[Scope of utility model registration request] 1. A plurality of signal transmission conductor layers and a ground /
Between the signal transmission conductor layer and the ground / power supply conductor layer of the circuit board having the power supply conductor layer, the thickness of the conductor in the signal transmission conductor layer is controlled so as to be impedance-matched. In a high-speed signal circuit board having a dielectric layer, a ground formed so as to surround the VIA land of the signal transmission conductor layer in which a predetermined VIA connecting the signal transmission conductor layers is provided. A high-speed signal circuit board having a pattern.