JPH08335754A - Guard structure employing via hole/through hole - Google Patents

Abstract

PURPOSE: To provide a guard structure for electronic circuit board employing via hole/through hole in which the effect of leakage current and inductive absorption can be reduced significantly. CONSTITUTION: The guard structure employs four rows of via hole/through hole wherein the ratio between the diameter of hole and the interval between adjacent rows is optimally set at 2:3. Assuming the diameter of hole is 8, first and second rows of hole have centers shifted by a length of 6, first and third rows of hole have centers shifted by a length of 4, and first and fourth rows of hole have centers shifted by a length of 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guard structure for an electronic circuit board, and more particularly, to a via hole / through hole which significantly reduces the influence of leakage current and the waiting time due to dielectric absorption when measuring a small current. It was about the guard structure.

[0002]

2. Description of the Related Art Conventionally, a signal having a high insulation and a good dielectric absorption characteristic for measuring a small amount of current on an electronic circuit board, in other words, a signal having a small leak current and a short measurement waiting time. Various structures have been devised to provide the wires.

As an example, there is a structure in which an insulator such as a clover leaf, a Teflon stud, or the like is used to provide a terminal insulated from the substrate on the substrate, and the terminal is used to perform aerial wiring. Since this structure uses the aerial wiring, it has a large effect of preventing the leakage current from the signal line and a large effect of reducing the current due to the dielectric absorption because there is only air between the conductor of another potential, but an insulator is provided on the substrate. Since the work and the soldering work of the wiring are manual work, the work cost is high, and the cost is not negligible together with the cost of the insulator parts.

Here, the leak current is a current that constantly flows into or out of the signal line through the insulating member, and the amount of the flow is independent of time. Dielectric absorption occurs when the dielectric space (insulating member) is included in the capacitance space formed between the signal line and the surrounding conductors, and the electric field applied to the capacitance space when either potential changes. Changes, and when the dielectric in this space undergoes dielectric polarization, the polarization occurs over time, causing a transient current flow.By waiting until the polarization ends, Converge. However, for example, when the terminal voltage changes by 100 V, it may take several tens of seconds until the value of the current due to the dielectric absorption settles down to about femtoamperes, and this long waiting time is long when measuring a minute current. It becomes a big problem.

On the other hand, in the structure in which the highly insulated signal line is provided on the electronic circuit board, the signal provided in the electronic circuit board 40 as shown in FIG. 1 is assumed to have the least influence by the leakage current and the dielectric absorption. There is a structure in which the upper and lower sides and the left and right sides of the line 10 are surrounded by guard patterns 12, 14, 16, and 18, and the via holes / through holes 20, 22 are arranged on the left and right sides. For ease of understanding, FIG. 1 is drawn as a perspective view with a sectional view in which the insulating portion of the substrate is transparent. Figure 2
FIG. 2 is a structural view of the signal line and guard structure shown in FIG. 1 as viewed from above.

Here, the via hole / through hole means
In both cases, in order to connect the conductors of different layers of the laminated plate, the holes penetrating between the laminated plates are plated so as to be electrically connected. A through hole refers to one that penetrates the entire laminated plate from the front to the back, and a via hole refers to one that penetrates only part of the conductor layers.

In the structure of FIG. 1, the leakage current from above and below the substrate such as the path 34 flows through the guard and does not flow into the signal line 10 because the guard pattern covers the signal lines above and below. . Further, the influence of the dielectric absorption from the conductor of the other potential on the path 34 is that the conductor of the other potential does not see the signal line 10 but only the guard 14 in that path, so that the current due to the dielectric polarization flows into the guard 14 and the signal. It does not flow into line 10. Guard 14 from signal line 10
However, it is preferable that the guard 14 be an active guard and have the same potential as that of the signal line, so that the influence of dielectric absorption due to potential fluctuations of the signal line 10 and the guard 14 can be ignored, but the guard 14 is passive. Even if a guard is used and made equal to the ground potential to eliminate the fluctuation of the guard potential, some effect can be expected. Similarly, the influence of the leakage current from the lateral direction and the dielectric absorption is partly blocked by the left and right guard patterns 16 and 18 as in the path 32, and partly in the guard of the via holes 20 and 22 as in the path 30. Disturbed. However, a considerable amount of leakage current and current due to dielectric absorption pass through between the lateral guard pattern 18 and the via hole 22 like the path 36 and flow into or out of the signal line 10.

In order to prevent this, the via holes / through holes for guard are provided without a gap and are arranged in a wall shape, so that the influence of the leakage current and the dielectric absorption can be almost prevented. However, if such via holes / through holes are connected without a gap over a certain distance, a problem arises in the mechanical strength of the substrate material. In addition, if a signal line with such a guard for a through hole is routed over the entire surface of the substrate, the inside of the substrate may be hollowed out in some cases, and it may not be possible to manufacture.

This problem also occurs when a wall-shaped conductor is introduced into the printed circuit board as a guard in place of the guard by a via hole / through hole in order to prevent a leakage current from the side.

Therefore, without lowering the strength of the substrate,
There is a demand for a guard structure that prevents the effects of lateral leakage current and dielectric absorption as much as possible.

An object of the present invention is to provide an electronic circuit board,
It is an object of the present invention to provide a guard structure using via holes / through holes which can significantly reduce the effects of leakage current and dielectric absorption.

[0012]

SUMMARY OF THE INVENTION In order to reduce the influence of leakage current and dielectric absorption on a signal line formed in an electronic circuit board, the present invention is connected to a guard pattern above and below the signal line, Beer holes for guards located on the left and right of /
The structure of the row of through holes was modified.

The present invention has a structure in which a plurality of via holes / through holes for guard are arranged in order to maintain the strength of the substrate. The cross section of each via hole / through hole is
Various shapes such as circle, ellipse and rectangle can be used. The distance between the center lines of each row is constant and the relative position between the center of the hole in each row and the center of the hole in the other row must be taken regardless of any straight path that runs from one side to the other. By setting it to be blocked by one of the via hole / through hole guards, it is possible to significantly reduce the leakage current in the lateral direction.

The via-hole / through-hole guard structure according to the present invention is preferably applied to a build-up substrate or a ceramic substrate by utilizing its fine processing technology, and a large area can be obtained even if the number of rows of holes is increased. Can be implemented without occupying. However, those skilled in the art will understand that other substrate materials and components can be used.

[0015]

EXAMPLES In the present specification, for convenience of description, there is a portion described as a via hole, but it is obvious to those skilled in the art that the via hole may be replaced with a through hole and adapted. Is.
It is also the same as applying the term "hole" by replacing it with a "hole" which indicates a through-hole.

FIG. 3 shows that the optimum diameter of the four holes according to the present invention is 4 when the ratio of the distance between the center lines of adjacent rows (the line passing through the centers of the holes forming the rows) is 2: 3. FIG. 5 shows a view from above of the main part of an embodiment of a guard structure with via holes or through holes in rows. Note that the dimensions shown in Figure 3 are not actual lengths, but ratios of lengths. In the row of four holes in FIG. 3, the deviation between the centers of the holes in the first row and the second row (the vertical distance between the centers of the holes 201 in the first row and the holes 202 in the second row) is The length is 6 when the diameter of the is 8 and the same deviation between the first row and the third row (the vertical interval between the centers of the holes 201 of the first row and the holes 203 of the third row) Is a length of 4, and the same deviation between the first row and the fourth row (the vertical distance between the centers of the holes 201 of the first row and the holes 204 of the fourth row)
Is 9 in length.

Thus, by adopting a structure in which a plurality of rows are arranged in an appropriate arrangement while leaving the substrate member between the holes,
The guard structure is such that, while maintaining the mechanical strength, the via hole / through hole aggregate structure cannot be electrically viewed through any straight path from one side to the other side. Therefore, when considering the influence of the leakage current from the conductor outside the guard structure and the dielectric absorption, only the guard can be seen from the outside instead of the signal line, and these influences can be significantly reduced.

FIG. 4 is a structural diagram of a guarded signal line using the via hole having the structure of FIG. For ease of understanding, FIG. 4 is drawn as a perspective view with a sectional view in which the insulating portion of the substrate is transparent. 101 and 102 are a group of via holes each having the structure / arrangement shown in FIG. 3, and are provided so as to connect the guard patterns 12 and 14 that cover the signal line 10 from above and below. Also, it has a structure that prevents dielectric absorption.

FIG. 5 is a structural view of the high-insulation signal line shown in FIG. 4 as seen from above. On both sides of the upper guard pattern 12, a group of via holes 101 and 102 shown in FIG. 3 are arranged.

FIG. 6 shows another structure having a via hole / through hole structure having five rows, which is optimum when the ratio of the hole diameter to the center line spacing between adjacent rows is 5: 8 according to the present invention. The figure which looked at the principal part of the Example of this from above is shown. Note that the dimensions shown in FIG. 6 also indicate the ratio of lengths, not the actual lengths. The row of five holes in FIG. 6 includes a first row and a second row.
The deviation of the centers of the holes in the rows (the vertical distance between the centers of the holes 211 in the first row and the holes 212 in the second row) is 4 when the diameter of the holes is 5, and Misalignment of the centers of the holes in the second row, the third row, and the fifth row (the center of the hole 212 in the second row and the hole 2 in the third row 2
There is no vertical gap between the center of 13 and the center of hole 215 in the fifth row, and there is a deviation between the centers of holes in the first and fourth rows (hole 21 in the first row).
There is also no vertical spacing between the center of 1 and the center of the holes 214 in the fourth row).

FIG. 7 shows another structure of a via hole / through hole structure having six rows, which is optimal according to the present invention when the ratio of the hole diameter to the center line spacing between adjacent rows is 1: 2. The figure which looked at the principal part of the Example of this from above is shown. Note that the dimensions shown in FIG. 7 also show the ratio of lengths, not the actual lengths. In the row of six holes in FIG. 7, the deviation between the centers of the holes in the first row and the second row (the vertical interval between the centers of the holes 221 in the first row and the holes 222 in the second row) is The length is 8 when the diameter of the is 8 and the same deviation between the first row and the third row (the vertical distance between the centers of the holes 221 of the first row and the holes 223 of the third row) Has a length of 13 and has a similar displacement between the first and fourth rows (the center of the holes 221 of the first row and the holes 224 of the fourth row).
The vertical distance between the centers of the two is 12 and the same misalignment between the first row and the fifth row (the center of the holes 221 in the first row and the holes 2 in the fifth row).
The vertical distance between the centers of 25 is 10 and the deviation between the centers of the holes in the first row and the sixth row (the center of the holes 221 in the first row and the sixth row).
There is no vertical spacing in the center of the rows of holes 226.

In each of the above-described embodiments, a build-up substrate or a ceramic substrate is preferably used as the substrate, and the microfabrication technology is used to form the via hole / through hole guard structure in a compact manner.

As an example, the diameter of the holes can be 100 μm in the build-up board. In this case, the width of each via hole group of this guard structure is 1.2 even in the structure of FIG. It fits in millimeters.

Further, in the above embodiment, the via hole /
By modifying the cross section of the through hole into an ellipse or a rectangle, a via hole / through hole structure having a similar effect can be produced.

Although the embodiments of the present invention have been described above, the exemplary forms, arrangements, and the like are not limited, and modifications of the configuration are allowed as necessary without losing the gist of the present invention.

[0026]

As described above, according to the present invention,
The following effects can be achieved. (1) It is possible to form a guard structure by a via hole / through hole on an electronic circuit board while significantly reducing influences of leakage current and dielectric absorption while maintaining mechanical strength. (2) When a signal line that covers the upper and lower sides with a guard pattern is provided on the electronic circuit board, a guard structure using via holes / through holes according to the present invention connected to the upper and lower guard patterns is provided beside the signal line. As a result, it is possible to form a guarded signal line with improved insulation performance and dielectric absorption characteristics at a low manufacturing cost.

[Brief description of drawings]

FIG. 1 is a perspective view of a guarded signal line provided in an electronic circuit board according to a conventional technique.

FIG. 2 is a structural diagram of the guarded signal line shown in FIG. 1 viewed from above.

FIG. 3 is a view from above of a via hole / through hole guard structure showing a main part of an embodiment of the present invention.

FIG. 4 is a perspective view of a guarded signal line using a guard structure with via holes shown in FIG. 3, which is an embodiment of the present invention.

5 is a structural diagram of the guarded signal line shown in FIG. 4 as viewed from above. FIG.

FIG. 6 is a top view of a via-hole / through-hole guard structure showing a main part of another embodiment of the present invention.

FIG. 7 is a view from above of a via-hole / through-hole guard structure showing the main part of another embodiment of the present invention.

[Explanation of symbols]

10: Signal line 12, 14: Guard pattern 38: Path 40: Electronic circuit board 101, 102: Via hole 200: Guard pattern 201, 202, 203, 204, 211, 212, 2
13, 214, 215, 221, 222, 223, 22
4, 225, 226: Via hole / through hole

Claims (5)

[Claims] 1. A signal line and a plurality of via holes / through holes as guards of the signal line, wherein the via holes / through holes are arranged adjacent to each other in a plurality of columns, and the via holes / through holes in each column are The guard structure is characterized by arranging the centers at different positions. 2. In the arrangement of via holes / through holes adjacent to each other in a plurality of columns, at least one via hole / through hole blocks all linear paths from one side to the other side. The described guard structure. 3. In the via hole / through hole arrangement, the cross section has four rows of circles, and the ratio of the diameter of each hole to the spacing between adjacent rows and the center line of the rows is 2: 3. The deviation between the center of each hole in the second row and the center of each hole in the first row is 6 when the diameter of the hole is 8 and the center of each hole in the third row and the first row The deviation of the center of each hole is 4 when the diameter of the hole is 8 and the deviation of the center of each hole in the fourth row from the center of each hole in the first row is The guard structure according to claim 1, wherein the length is 9 when the diameter is 8 in length. 4. In the via hole / through hole arrangement, the cross section has five rows of circles, and the ratio of the diameter of each hole to the distance between adjacent rows and the center line of the rows is 5: 8. The deviation between the center of each hole in the second row and the center of each hole in the first row is 4 when the diameter of the hole is 5 and the length of the second row, the third row and the fifth row is The guard structure according to claim 1, wherein the centers of the holes are not displaced, and the centers of the holes in the first row and the fourth row are not displaced. 5. In the via hole / through hole arrangement, the cross section has six rows of circles, and the diameter of each hole has a ratio of the spacing between adjacent rows and the center line of the rows of 1: 2, The deviation between the center of each hole in the second row and the center of each hole in the first row is 8 when the diameter of the hole is 8 and the center of each hole in the third row and the first row The deviation of the center of each hole is 13 when the diameter of the hole is 8 and the deviation of the center of each hole in the fourth row from the center of each hole in the first row is If the diameter is 8 and the length is 12, the deviation between the center of each hole in the fifth row and the center of each hole in the first row is 10 if the diameter of the hole is 8 The guard structure according to claim 1, wherein the centers of the holes in the sixth row and the holes in the first row are not displaced.