JP2017045870A - Characteristic impedance matching wiring board, and characteristic impedance matching method of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the electrical characteristics of a wiring board by suppressing variation of the characteristic impedance in each wiring region, in a wiring board including at least two wiring layers (conductor layers) having a degassing hole and facing each other, and a wiring pattern including the wiring for use in signal transmission and the like.MEANS FOR SOLVING THE PROBLEM: In a wiring board including a first conductor layer in which a plurality of first degassing holes are formed, a second conductor layer disposed oppositely to the first conductor layer, and in which a plurality of second degassing holes are formed, an isolating layer for electrically isolating the first and second conductor layers, and a wiring layer including a plurality of wirings disposed substantially in parallel with the first and second conductor layers, in the isolating layer, the plurality of wirings are routed to superpose on the first and second conductor layers, when viewing from a direction perpendicular to a plane defined by the first and second conductor layers.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a characteristic impedance matching wiring board that can be suitably used in information communication equipment and mobile communication equipment, and a characteristic impedance matching method for the wiring board.

  In recent years, electronic devices are required to have higher density and higher functionality in the trend of higher performance and smaller size. From this point of view, even modules with circuit components are required to support high density and high functionality. In order to meet such demands, multilayer wiring boards are now being actively performed.

  Depending on the manufacturing technology and material requirements, in order to enable proper operation of the wiring board, a number of degassing holes may be formed in the wiring layer (conductor layer) constituting the wiring board. The degassing holes are for preventing the gas from evaporating or vaporizing and forming bubbles in the package.

  On the other hand, for example, the wiring for taking out a signal from the wiring board can be routed above or below the degassing hole, routed around the degassing hole, or a combination thereof.

  A typical degassing hole pattern includes a degassing hole formed in the first wiring layer (conductor layer) and a second wiring layer disposed to face the first wiring layer. A degassing hole formed in the (conductor layer) is formed so as to be aligned in a direction perpendicular to a plane formed by these two wiring layers to constitute a grid-like (lattice-like) array.

  On the other hand, in the routing of the conventional wiring in the wiring board, for example, if the wiring is classified into the first wiring and the second wiring, for example, the first wiring is compared with the second wiring. In some cases, the proportion of the wiring layer present on both the upper and lower sides of the first wiring is reduced. Therefore, when the above-described routing is performed on the first wiring and the second wiring, these wirings cause a large variation in characteristic impedance.

  In order to cope with such a problem, in Patent Document 1, for example, a first wiring (metal trace) and a second wiring (metal trace) are removed so as to form a grid-like (lattice-like) array. For the gas hole pattern, for example, the first wiring is routed across the approximate center of the degassing hole, and the second wiring is routed across the edge of the degassing hole. It is made to pass through the degassing hole, and the characteristic impedance fluctuation is suppressed.

  However, even in the technique described in Patent Document 1, the suppression of fluctuations in characteristic impedance when wiring is arranged on a wiring board in which a degassing hole is formed varies greatly for each region where the wiring is wired. There is a problem that the characteristic impedance of the intended wiring board, that is, the electric characteristics cannot be stabilized.

Japanese Patent No. 4671470

  The present invention relates to a wiring board including at least two opposing wiring layers (conductor layers) in which a degassing hole is formed and a wiring pattern including a wiring used for signal transmission or the like. An object is to stabilize the electrical characteristics of the wiring board by suppressing fluctuations in each wiring area.

In order to achieve the above object, the present invention provides:
A first conductor layer formed with a plurality of first degassing holes;
A second conductor layer disposed opposite to the first conductor layer, wherein a plurality of second degassing holes are formed;
An insulating layer for electrically insulating the first conductor layer and the second conductor layer;
In the insulating layer, comprising a wiring layer including a plurality of wirings arranged substantially parallel to the first conductor layer and the second conductor layer,
The plurality of wirings overlap with the first conductor layer and the second conductor layer when viewed in a direction perpendicular to a plane defined by the first conductor layer and the second conductor layer. The characteristic impedance matching wiring board is characterized by being routed in this manner.

The present invention also provides:
A first conductor layer formed with a plurality of first degassing holes and a second conductor layer disposed so as to oppose the first conductor layer and formed with a plurality of second degassing holes. A conductive layer, an insulating layer for electrically insulating the first conductive layer and the second conductive layer, and the first conductive layer and the second conductive layer in the insulating layer, In a wiring board comprising a wiring layer including a plurality of wirings arranged in parallel,
The plurality of wirings overlap the first conductor layer and the second conductor layer when viewed in a direction perpendicular to a plane defined by the first conductor layer and the second conductor layer. Thus, the present invention relates to a characteristic impedance matching method for a wiring board, characterized in that routing is performed in this manner.

  According to the present invention, the wiring of the wiring layer constituting the wiring board includes a first conductor layer having a first degassing hole and a second conductor layer having a second degassing hole located above and below the wiring layer. When viewed in a direction perpendicular to the plane defined by these conductor layers, the conductor layers are always arranged so as to overlap. That is, in any wiring region of the wiring layer, the metal layer constituting the conductor layer exists above and below the wiring constituting the wiring layer. Therefore, the characteristic impedance is almost the same in any wiring region, and it is possible to provide a wiring board having stable electrical characteristics in which the characteristic impedance does not change for each wiring region.

  For this reason, the transmission capability of the signal which transmits the wiring of the wiring layer which comprises the said wiring board can be aimed at. In addition, since it is not necessary to change the design of the degassing hole in order to make the characteristic impedance of each wiring region the same, it is possible to reduce the design man-hours.

  In an example of the present invention, the plurality of first degassing holes and the plurality of second degassing holes have the same size, and the formation positions thereof are defined as the first conductor layer and the second degassing hole. They can coincide with each other in a direction perpendicular to the plane defined by the conductor layers. That is, in the coordinates of the plane defined by the first conductor layer and the second conductor layer, the coordinates of the first degassing hole and the second degassing hole can be matched.

  In this case, the structure of the wiring layer as described above, that is, the structure in which the metal layer constituting the conductor layer exists above and below the wiring constituting the wiring layer easily in any wiring region of the wiring layer. be able to. Therefore, the above-described operational effects can be realized more easily.

  As described above, according to the present invention, in a wiring board including at least two opposing wiring layers (conductor layers) in which a degassing hole is formed and a wiring pattern including wiring used for signal transmission, the wiring board The fluctuation of the characteristic impedance for each wiring region can be suppressed, and the electrical characteristics of the wiring board can be stabilized.

It is a top view which shows schematic structure of the characteristic impedance matching wiring board of embodiment. It is sectional drawing at the time of cutting along the II-II line of the characteristic impedance matching wiring board shown in FIG. It is sectional drawing at the time of cutting along the III-III line of the characteristic impedance matching wiring board shown in FIG. It is sectional drawing at the time of cutting along the IV-IV line of the characteristic impedance matching wiring board shown in FIG.

  Hereinafter, specific features of the present invention will be described based on embodiments for carrying out the invention.

  FIG. 1 is a plan view showing a schematic configuration of a characteristic impedance matching wiring board of the present embodiment. FIGS. 2 to 4 are II-II line and III-III line of the characteristic impedance matching wiring board shown in FIG. 1, respectively. FIG. 4 is a cross-sectional view taken along line IV-IV.

  For convenience of explanation, the x coordinate axis is taken in the horizontal direction, the y coordinate axis is taken in the vertical direction, and the z coordinate axis is taken in the thickness direction of the characteristic impedance matching wiring board of the present embodiment.

  As shown in FIGS. 1 to 4, the characteristic impedance matching wiring board (hereinafter also referred to as “wiring board”) 10 of the present embodiment has a first degassing hole 11 </ b> H formed therein. It has a conductor layer 11 and a second conductor layer 12 that is disposed to face the first conductor layer 11 and has a plurality of second degassing holes 12H.

  The first degassing hole 11H and the second degassing hole 12H are formed to enable proper operation of the wiring board 10 by, for example, manufacturing technology and material requirements. The gas stored and adsorbed in the material of the wiring board 10 evaporates or vaporizes through 11H and 12H, so that bubbles caused by the gas are not formed in the package including the wiring board 10. .

  In the present embodiment, the number of the first degassing holes 11H and the second degassing holes 12H is formed in four rows in the horizontal direction (x direction) and four rows in the vertical direction (y direction), respectively. Although a total of 16 holes are provided, the number of these degassing holes can be any number as required.

  Further, as is apparent from FIGS. 1 and 3, the first degassing hole 11H and the second degassing hole 12H have the same size, and their positions are defined by the first conductor layer 11 and the second degassing hole 11H. They are made to coincide with each other in the direction (z direction) perpendicular to the plane (xy plane) defined by the second conductor layer 12.

  An insulating layer 13 is provided between the first conductor layer 11 and the second conductor layer 12 to electrically insulate them. In the insulating layer 13, the first conductor layer 11 and the second conductor layer 12 are disposed. A wiring layer 14 including a plurality of wirings 141, 142, and 143 arranged in parallel to the two conductor layers 12 (xy plane defined by the first conductor layer 11 and the second conductor layer 12). ing.

  In the present embodiment, the number of wirings included in the wiring layer 14 is 3, but can be any number as necessary.

  In the x direction, the wiring 141 goes straight between two degassing holes 11H (12H) adjacent in the y direction by two degassing holes 11H (12H), and then bends downward at a predetermined angle. It is routed to go straight through one degassing hole 11H (12H) along the y direction.

  The wiring 142 is routed in the x direction so as to go straight between the two degassing holes 11H (12H) adjacent in the y direction by four degassing holes 11H (12H). In the y direction, the wiring 143 goes straight between the two degassing holes 11H (12H) adjacent in the x direction by one degassing hole 11H (12H) and then bent to the right at a predetermined angle. Thereafter, the route is specified so as to go straight through one degassing hole 11H (12H) along the x direction.

  In the wiring substrate 10 of the present embodiment, all of the wirings 141 to 143 routed as described above have the first degassing holes 11H positioned above and below as shown in FIGS. When viewed in a direction (z direction) perpendicular to a plane (xy plane) defined by the first conductor layer 11 and the second conductor layer 12 having the second degassing hole 12H and these conductor layers The conductor layers 11 and 12 are always arranged so as to overlap.

  That is, in any wiring region of the wiring layer 14, the metal layers constituting the conductor layers 11 and 12 exist above and below the wirings 141 to 143 constituting the wiring layer 14. Therefore, the characteristic impedance is almost the same in any wiring region, and it is possible to provide the wiring board 10 having stable electrical characteristics in which the characteristic impedance does not change for each wiring region.

  For this reason, the transmission capability of the signal which transmits the wiring of the wiring layer 14 which comprises the wiring board 10 can be aimed at. In addition, since it is not necessary to change the design of the degassing hole in order to make the characteristic impedance of each wiring region the same, it is possible to reduce the design man-hours.

  The first conductor layer 11 and the second conductor layer 12 can be used as, for example, a power supply layer or a ground layer.

  Further, as described above, in the present embodiment, the first degassing hole 11H and the second degassing hole 12H have the same size as each other, and their positions are defined by the first conductor layer 11 and They are made to coincide with each other in the direction (z direction) perpendicular to the plane (xy plane) defined by the second conductor layer 12.

  In this case, the structure of the wiring layer 14 as described above, that is, in any wiring region of the wiring layer 14, the metal layers constituting the conductor layers 11 and 12 exist above and below the wirings 141 to 143 constituting the wiring layer. Such a structure can be configured easily. Therefore, the above-described operational effects can be realized more easily.

  In addition, the wiring board 10 of this embodiment can be manufactured based on the design rule which is demonstrated below, for example.

  First, the arrangement pitch P1 of the first degassing holes 11H and the second degassing holes 12H and the arrangement pitch P2 of the wirings 141 to 143 are made the same. Next, the size W1 of the first degassing holes 11 and the second degassing holes 12H is set to ½ or less of the arrangement pitch P1 of the first degassing holes 11H and the second degassing holes 12H. And the width W2 of the wiring 141-143 is made into 1/4 or less of arrangement pitch P1 of the 1st degassing hole 11H and the 2nd degassing hole 12H. Then, the wirings 141 to 143 are arranged with a half-pitch shift from the arrangement positions of the first degassing holes 11H and the second degassing holes 12H.

  That is, in the wiring board 10 of the present embodiment, it is possible to provide the wiring board 10 having stable electrical characteristics in which the characteristic impedance does not change for each wiring region only by using the simple design rule as described above.

  Further, for example, if the width W2 of the wirings 141 to 143 is set to 1/8 or less of the arrangement pitch P1 of the first degassing holes 11H and the second degassing holes 12H, the above design rule satisfies the first degassing holes. In the arrangement pitch P1 of the gas holes 11H and the second degassing holes 12H, the two wirings 141 to 143 can be disposed, and can be applied to the design of the wiring structure of the differential transmission line. Therefore, the wiring structure of the differential transmission line can be formed in the wiring board 10 of the present embodiment.

  The present invention has been described in detail based on the above specific examples. However, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Characteristic impedance matching wiring board 11 1st conductor layer 11H 1st degassing hole 12 2nd conductor layer 12H 2nd degassing hole 13 Insulating layer 14 Wiring layer 141,142,143 Wiring

Claims (4)

A first conductor layer formed with a plurality of first degassing holes;
A second conductor layer disposed opposite to the first conductor layer, wherein a plurality of second degassing holes are formed;
An insulating layer for electrically insulating the first conductor layer and the second conductor layer;
In the insulating layer, comprising a wiring layer including a plurality of wirings arranged in parallel with the first conductor layer and the second conductor layer,
The plurality of wirings overlap with the first conductor layer and the second conductor layer when viewed in a direction perpendicular to a plane defined by the first conductor layer and the second conductor layer. Characteristic impedance matching wiring board, characterized in that it is routed in this way.   The plurality of first degassing holes and the plurality of second degassing holes have the same size, and their formation positions are the first conductor layer and the second conductor layer. The characteristic impedance matching wiring board according to claim 1, wherein the characteristic impedance matching wiring boards match each other in a direction perpendicular to a plane defined by A first conductor layer formed with a plurality of first degassing holes and a second conductor layer disposed so as to oppose the first conductor layer and formed with a plurality of second degassing holes. A conductive layer, an insulating layer for electrically insulating the first conductive layer and the second conductive layer, and the first conductive layer and the second conductive layer in the insulating layer, In a wiring board comprising a wiring layer including a plurality of wirings arranged substantially in parallel,
The plurality of wirings overlap the first conductor layer and the second conductor layer when viewed in a direction perpendicular to a plane defined by the first conductor layer and the second conductor layer. Wiring board characteristic impedance matching method, characterized in that routing is performed in this manner.   The plurality of first degassing holes and the plurality of second degassing holes have the same size, and their formation positions are defined by the first conductor layer and the second conductor layer. 4. The characteristic impedance matching method for a wiring board according to claim 3, wherein the wiring boards are made to coincide with each other in a direction perpendicular to the plane.

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