JP2007129138A - Printed circuit substrate and mounting substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit substrate and a mounting substrate which can simply prevent interference by an electromagnetic induction between signal lines. <P>SOLUTION: The printed circuit substrate 1 has a plurality of lands 11 formed in its top surface. A grounded wiring pattern 16a is formed on the top surface of the printed-circuit substrate 1 between a first land 11a transmitting one signal (for example, not a critical signal) and a second land 11b transmitting other signal (for example, a critical signal, such as a clock signal). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printed circuit board and a mounting board in which a plurality of lands are formed on one surface.

  In a conventional printed circuit board, a copper foil pattern layer such as a power supply line and a ground line is formed on the surface of a substrate to be an insulating layer, and a copper foil pattern layer of a signal line and a circuit pattern is formed on the copper foil pattern layer via the insulating layer. Is formed.

  In this type of printed circuit board, as the operating frequency increases, the electromagnetic coupling between the signal lines becomes dense, so that the signals interfere with each other, and this signal interference may cause malfunction of the circuit. . In order to solve this problem, various proposals for reducing interference between signal lines of the printed circuit board have been disclosed.

For example, in Patent Document 1, in a multilayer printed circuit board, a circuit pattern serving as a signal line of the board is formed, and both sides of the signal line are formed so as to be surrounded by a planar pattern of power supply lines (or ground lines). A printed circuit board characterized in that is described.
JP 2002-118340 A

  In this printed circuit board, interference by electromagnetic induction between signal lines can be prevented by surrounding both sides of the signal lines with a planar pattern of conductive power supply lines (or ground lines).

  However, a manufacturing process for forming a printed circuit board is necessary because a manufacturing process for forming a planar pattern for preventing electromagnetic induction between signal lines is required separately from a manufacturing process for forming a circuit pattern to be a signal line. As the number of processes increases, the manufacturing cost of the printed circuit board increases.

  The present invention has been made in view of such problems, and an object thereof is to provide a printed circuit board and a mounting board that can easily prevent interference due to electromagnetic induction between signal lines.

  In order to achieve the above object, the printed circuit board according to claim 1 is a printed circuit board having a plurality of lands formed on one side, wherein one land and one other signal are transmitted. A ground pattern, which is a grounded wiring pattern, is formed on the one surface between the other lands that transmit the signal.

  According to the above configuration, the ground between one land to which one signal is transmitted and the other land to which another signal is transmitted is grounded on one surface of the substrate on which these lands are formed. Since the ground pattern, which is a wiring pattern, is formed, interference due to electromagnetic induction between the signal lines is easily prevented by the ground pattern.

  The printed circuit board according to claim 2, wherein the printed circuit board according to claim 1 is a multilayer board having a ground layer grounded, wherein the ground pattern is connected to the ground layer via at least one via. It is characterized by being connected to be energized.

  According to the above configuration, since the ground pattern is connected to the ground layer through at least one via so as to be energized, the ground pattern can be easily and reliably grounded.

  The printed circuit board according to claim 3 is the printed circuit board according to claim 2, wherein both ends of the ground pattern are connected to the ground layer through vias so as to be energized. .

  According to the above configuration, since both ends of the ground pattern are connected to the ground layer through the vias so as to be energized, the ground pattern can be more reliably grounded.

  The printed circuit board according to claim 4 is the printed circuit board according to any one of claims 1 to 3, wherein an angle formed by two line segments connecting both ends of the ground pattern and the one land, and At least one of the angles formed by two line segments connecting both ends of the ground pattern and the other lands is a predetermined angle or more.

  According to the above configuration, at least an angle formed by two line segments connecting both ends of the ground pattern and one land, and an angle formed by two line segments connecting the both ends of the ground pattern and other lands. Since one of the angles is equal to or greater than a predetermined angle (for example, 90 degrees), interference due to electromagnetic induction between the signal lines can be prevented more reliably than when the angle is less than the predetermined angle.

  A printed circuit board according to a fifth aspect is the printed circuit board according to the fourth aspect, wherein the predetermined angle is approximately 180 degrees.

  According to said structure, since the said predetermined angle is about 180 degree | times, interference by the electromagnetic induction between signal lines is prevented more reliably.

  The mounting board according to claim 6 is a mounting board having the printed circuit board according to any one of claims 1 to 5 and a BGA, wherein the first land and the other lands of the printed circuit board are: Each is connected to the BGA solder ball terminal so as to be energized, and the signal 1 and the other signal are transmitted through the solder ball terminal.

  According to the above configuration, one land and another land of the printed circuit board are connected to the BGA solder ball terminals so as to be energized, and one signal and other signals are transmitted via the solder ball terminals. Therefore, interference due to electromagnetic induction between a signal line that transmits one signal and a signal line that transmits another signal is easily prevented.

  According to the printed circuit board according to claim 1, one side of the board on which these lands are formed between one land to which one signal is transmitted and another land to which another signal is transmitted. Since a ground pattern, which is a grounded wiring pattern, is formed on the top, interference due to electromagnetic induction between signal lines can be easily prevented by the ground pattern.

  According to the printed circuit board of the second aspect, since the ground pattern is connected to the ground layer through at least one via so as to be able to be energized, the ground pattern can be easily and reliably grounded.

  According to the printed circuit board according to the third aspect, since both ends of the ground pattern are connected to the ground layer through the vias so as to be energized, the ground pattern can be more reliably grounded.

  According to the printed circuit board according to claim 4, the angle formed by two line segments connecting both ends of the ground pattern and one land, and two lines connecting the both ends of the ground pattern and other lands. Since at least one of the divided angles is a predetermined angle (for example, 90 degrees) or more, interference due to electromagnetic induction between the signal lines can be prevented more reliably than when the angle is less than the predetermined angle.

  According to the printed circuit board of the fifth aspect, since the predetermined angle is approximately 180 degrees, it is possible to more reliably prevent interference due to electromagnetic induction between the signal lines.

  According to the mounting board according to claim 6, one land and another land of the printed circuit board are connected to the solder ball terminal of the BGA so as to be energized, and one signal and the other land are connected via the solder ball terminal. Since other signals are transmitted, interference due to electromagnetic induction between the signal line transmitting one signal and the signal line transmitting another signal can be easily prevented.

  Hereinafter, a printed circuit board (so-called printed wiring board) and a mounting board according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a mounting board according to an embodiment of the present invention, FIG. 2 is a top view of a printed circuit board 1 according to an embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view (cross-sectional view taken along the line XX in FIG. 2) of a mounting board having a circuit board 1 and a BGA (Ball Grid Array) 2, and FIG. 4 is a view for explaining a predetermined angle described later.

  As shown in FIG. 1, the mounting board has a printed circuit board 1 having a plurality of lands 11 formed on one surface (here, the upper surface) and a BGA 2, and is formed on the upper surface of the printed circuit board 1. The predetermined number (for example, 25 places) of lands 11 and the predetermined number (for example, 25 places) of the solder ball terminals 21 of the BGA 2 are connected to be energized. Here, it is assumed that the lands 11 of the printed circuit board 1 and the solder ball terminals 21 of the BGA 2 are formed in a lattice shape (for example, 5 rows × 5 rows = 25 columns).

  The BGA 2 has an IC (Integrated Circuit) chip mounted on a ceramic or plastic substrate and sealed, and a large number of solder ball terminals 21 serving as external terminals are arranged in a grid pattern on the bottom surface of the substrate (here, 25 locations). It is formed and is surface-mounted on one surface (here, the upper surface) of the printed circuit board 1. Specifically, the BGA 2 is formed on the surface of the printed circuit board 1 by bonding the solder ball terminals 21 to the 25 lands 11 on the upper surface of the printed circuit board 1 by welding the solder balls. Implemented. Thus, the 25 lands 11 formed on one surface (here, the upper surface) of the printed circuit board 1 and the 25 solder ball terminals 21 of the BGA 2 are connected to each other so as to be energized.

  Although not described in detail, the BGA 2 includes a solder ball terminal 21 as a clock signal terminal to which a clock signal is transmitted, a solder ball terminal 21 as a ground terminal, a solder ball terminal 21 as a power supply terminal, and other terminals. Solder ball terminals 21 and the like as input / output signal terminals are formed.

  Here, the printed circuit board 1 is a substrate in which a plurality of wiring patterns are formed inside a base part (insulating part) 12 formed of an insulating plate (here, a four-layer printed circuit board), Here, a two-layer wiring pattern of a ground (GND) layer 13 and a power supply layer 14 is formed as a wiring pattern. That is, the printed circuit board 1 is a multilayer board having a ground layer 13 that is grounded. Note that resin, glass, or the like can be used as the insulating plate constituting the base portion 12, and a solder resist 15 is attached to the other surface (here, the lower surface) of the printed circuit board 1. Also, the solder ball terminal 21 as the ground terminal described above is connected to the ground layer 13 through the land 11 so as to be energized, and the solder ball terminal 21 as the power supply terminal is connected to the power layer 14 through the land 11. It is designed to be connected as possible.

  On the upper surface of the printed circuit board 1, substantially identical circular conductor patterns made of, for example, copper foil (Cu) are arranged in a grid pattern (here, in the row direction 5) so that the solder ball terminals 21 of the BGA 2 are connected to be energized. X The lands 11 (including 11a to 11d) disposed in the column direction 5 = 25 locations) are provided (see FIG. 2).

  Specifically, the upper surface of the printed circuit board 1 corresponds to a first land 11a (an example of a 1 signal) to which a predetermined signal excluding a critical signal such as a clock signal (an example of a 1 signal) is transmitted. ), A second land 11b (11: corresponding to another land) to which a clock signal that is a critical signal (an example of another signal) is transmitted, and both ends of a ground pattern 16a that is a grounded wiring pattern. Corresponding third lands 11c (11) and fourth lands 11d (11) are provided.

  Further, on the upper surface of the printed circuit board 1, there is formed a first signal line 17 which is a wiring pattern for transmitting the predetermined signal and is connected to the first land 11a so as to be energized. The predetermined signal is transmitted to the solder ball terminal 21 as the input / output terminal of the BGA 2 via the first signal line 17. Furthermore, on the upper surface of the printed circuit board 1, a second signal line 18, which is a wiring pattern through which a clock signal is transmitted, is connected to the second land 11 b so as to be energized. A clock signal is transmitted to the solder ball terminal 21 as a clock signal terminal of the BGA 2 via the two signal lines 18.

  As described above, the first land 11a and the second land 11b of the printed circuit board 1 are connected to the solder ball terminal 21 of the BGA 2 so as to be energized, and a predetermined signal and clock are transmitted via the solder ball terminal 21. A signal is transmitted.

  Further, the ground, which is a grounded wiring pattern, is disposed on the upper surface of the printed circuit board 1 between the first land 11a to which the predetermined signal is transmitted and the second land 11b to which the clock signal is transmitted. A pattern 16a is formed. As shown in FIG. 3, the third land 11c and the fourth land 11d, which are both ends of the ground pattern 16a, are connected to the ground via vias 19a and 19b suspended from the base portion 12 of the printed circuit board 1, respectively. The layer 13 is connected to be energized. That is, both ends of the ground pattern 16a (here, the third land 11c and the fourth land 11d) are connected to the ground layer 13 through the vias 19a and 19b so as to be energized.

  Here, both ends of the ground pattern 16a are connected to the ground layer 13 through the two vias 19a and 19b so as to be energized. However, the ground pattern 16a is connected to at least one via 19 (here, the via 19a and the via 19a and 19b). The ground layer 13 may be connected to be energized through either one of the vias 19b. As described above, even when the ground pattern 16a is connected to the ground layer 13 through the one via 19 so as to be energized, the ground pattern 16a can be grounded easily and reliably. By connecting the ground pattern 16a to the ground layer 13 through the two vias 19a and 19b so as to be energized, the ground pattern 16a can be more reliably grounded, so that both ends of the ground pattern 16a are connected to the two vias 19a and 19a. It is preferable to connect through 19b so that energization is possible.

  The area and shape in which the ground pattern 16a is formed is particularly suitable if the ground pattern 16a is formed on one surface between the first land 11a and the second land 11b (here, on the upper surface of the printed circuit board 1). Although not limited, here, the ground pattern 16a has two ends (here, the third land 11c and the fourth land 11d) and the second land 11b (corresponding to other lands). Are formed so that the angle (angle θ) formed by the line segments (here, the line segment CB and the line segment DB) is approximately 180 degrees (an example of a predetermined angle) (see FIG. 4A).

  As a result, the ground pattern 16a is formed so as to surround the second land 11b and the second signal line 18 more entirely than when the angle θ is less than a predetermined angle (here, 180 degrees). , Interference due to electromagnetic induction between the signal lines (here, between the first signal line 17 and the second signal line 18) can be more reliably prevented. Therefore, it is possible to prevent noise from being radiated to the outside from the first signal line 17 by superimposing noise due to the clock signal on the predetermined signal.

  FIG. 4B is a diagram showing a ground pattern 16b (a modification of the ground pattern 16a) when the angle θ is about 235 degrees. According to this ground pattern 16b, here, since the ground pattern 16b is formed so as to further surround the second land 11b and the second signal line 18, interference between the signal lines by electromagnetic induction is more reliably performed. Can be prevented.

  In addition, this invention is not limited to the said embodiment, The following forms may be sufficient. That is, in this embodiment, the land 11 to which a non-critical signal is transmitted is the first land 11a, and the land 11 to which a critical signal (here, a clock signal) is transmitted is the second land 11b. However, the land 11 to which a non-critical signal is transmitted may be the second land 11b, and the land 11 to which the critical signal is transmitted may be the first land 11a. Of course, signals that are critical to each other may be used.

  In the present embodiment, two line segments (line segments CB and CB) that connect both ends (center C and center D) of the ground pattern 16a or 16b and B of the second land 11b (corresponding to other lands). Although the case where the angle formed by the line segment DB) is approximately 180 degrees (an example of the predetermined angle) or more has been described, both ends (center C and center D) of the ground pattern 16a or 16b and the first land 11a (one land) An angle formed by two line segments (line segment CA and line segment DA) connecting with the center A of (corresponding) may be a predetermined angle (for example, 180 degrees) or more.

    The present invention is applicable to, for example, a printed circuit board and a mounting board in which a plurality of lands are formed on one surface.

It is sectional drawing of the mounting substrate which concerns on embodiment of this invention. It is a top view which shows the land and wiring pattern which were formed on the upper surface of a printed circuit board. FIG. 3 is a sectional view taken along line XX in FIG. 2. It is a figure for demonstrating a predetermined angle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 11 Land 11a (11) 1st land 11b (11) 2nd land 11c (11) 3rd land 11d (11) 4th land 13 Ground layer 16a, 16b Ground pattern 19, 19a, 19b Via 2 BGA
21 Solder ball terminal θ angle (predetermined angle)

Claims (6)

A printed circuit board having a plurality of lands formed on one side,
A ground pattern which is a grounded wiring pattern is formed on the one surface between one land where one signal is transmitted and another land where other signals are transmitted. Printed circuit board. A multilayer substrate having a grounded ground layer,
The printed circuit board according to claim 1, wherein the ground pattern is connected to the ground layer through at least one via so as to be energized.   The printed circuit board according to claim 2, wherein both ends of the ground pattern are connected to the ground layer through vias so as to be energized.   At least one of an angle formed by two line segments connecting both ends of the ground pattern and the one land, and an angle formed by two line segments connecting the both ends of the ground pattern and the other lands, The printed circuit board according to claim 1, wherein the printed circuit board has a predetermined angle or more.   The printed circuit board according to claim 4, wherein the predetermined angle is approximately 180 degrees. A mounting substrate comprising the printed circuit board according to claim 1 and a BGA,
The one land and the other land of the printed circuit board are connected to the solder ball terminals of the BGA so as to be energized, and the signals of the first and other signals are transmitted through the solder ball terminals. Mounting board characterized by

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