JP2000206171A - Method and device for inspecting wiring of printed circuit board, and wiring pattern producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a radiant noise by comparing angles with each other which a straight line connecting points of analysis coordinates at locations at the same wiring length from the input point or output point of the plus and minus signal wires of the differential signal line of a wiring pattern forms with the plus signal wire and the minus signal wire to detect a phase difference. SOLUTION: Location information (a start point, an end point, the coordinates of a point of bending, layers, etc.), necessary for forming the wiring pattern of a differential signal line is extracted from the CAD data of a wiring board. The wiring length of a wiring to be inspected is computed from the extracted coordinates of the start point, end point, and point of bending of the wiring to be inspected, and the difference in wiring length between signal wires (a plus wire and a minus wire) which form a pair with the wiring to be inspected and is obtained and compared with Ldiff (the allowable value of difference in wiring length). In the case where the difference in wiring length is shorter than the Ldiff, phase difference detection is performed. In the case that it is longer, alarm processing is performed. In the case that the sum of the wiring lengths in a section with a phase difference is longer than Lmax, alarm processing is performed. In the case that it is shorter, checks on the signal wires to form a pair are completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wiring inspection method for a wiring board on which a high-speed differential signal is mounted, an inspection apparatus using the method, and a wiring pattern generation apparatus.

[0002]

2. Description of the Related Art In recent years, a low-amplitude differential transmission system has been used as a data transfer system to a liquid crystal display (LCD). The differential transmission method is a method of generating two-phase signals of a + signal (+ line) and a − signal (− line) from one signal and transmitting the signal using two signal lines. In this system, the + line and the-line are electromagnetically coupled, so that the antenna loop area formed by the signal line and the return current path can be made close to zero, and compared with the conventional single-ended transmission system. Noise in the differential mode can be reduced.

In order to mount a differential signal, wiring must be parallel and of equal length. Refer to “Allegro User Guide Volume 3B pp 4-85
As shown by “-4-87 CADENCE,” there is a method of checking the total length or total delay of two nets.

[0004]

In the conventional inspection method,
The driver 182 to the receiver 183 as shown in FIG.
In the case of the wiring pattern 181, there is no error because the wiring pattern lengths of the + line and the − line from the driver 182 to the receiver 183 are equal. However, section A,
In B and C, the wiring patterns are parallel to each other, but the propagating signal has a phase difference generated in a detour portion. Therefore, +
The electromagnetic coupling between the line and the-line is broken, which causes radiation noise. For example, 75 in the lower wiring model of FIG.
Simulation of radiation noise when a 0-MHz rectangular wave was input showed the relationship between the detour deviation and the noise level of the 750-MHz radiation noise in the upper graph of FIG. As can be seen from this graph, the greater the deviation of the detour, the greater the radiation noise. In the conventional inspection method,
Since no consideration is given to the phase difference between the + line and the-line, there is a problem that such a wiring pattern cannot be checked.

Accordingly, an object of the present invention is to provide a wiring inspection method capable of detecting a phase difference between a positive line and a negative line of a differential signal as described above, an inspection apparatus using the method, and a wiring pattern generating apparatus. Is to do.

[0006]

In order to achieve the above object, the present invention provides a method for inspecting wiring of a printed circuit board.
The phase difference between the + signal and the − signal of the differential signal line of the wiring pattern to be inspected is detected.

According to the present invention, in a method for inspecting wiring of a printed circuit board, the signal propagation direction on the + signal line and the-signal line of the differential signal line which is the wiring pattern to be inspected,
Generating analysis coordinates at a predetermined wiring length interval; and obtaining a straight line connecting analysis coordinate points having the same wiring length from input or output points of the + signal line and the-signal line, and determining the straight line and the + signal line. And-calculate the angle formed by the signal line, respectively,
The method includes the steps of comparing the angles and detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison.

Further, according to the present invention, in a method of inspecting wiring of a printed circuit board, analysis coordinates are provided at a predetermined wiring length interval in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line as a wiring pattern to be inspected. Generating
A straight line connecting the points of the analysis coordinates having the same wiring length from the input point or the output point of the + signal line and the − signal line is obtained, and the angles formed by the straight line and the + signal line and the − signal line are calculated. Comparing the angles, detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison, and generating the phase difference for all the analysis coordinates on the + signal line and the − signal line. Detecting the sum of the section lengths of the sections having a phase difference, determining whether the sum of the section lengths of the sections having the phase difference is smaller than a predetermined value, And outputting a warning when the sum of the section lengths of the sections having a certain length is not smaller than a predetermined value.

Further, the present invention is a storage medium storing a program for inspecting wiring of a printed circuit board, wherein the program is stored on a positive signal line and a negative signal line of a differential signal line which is a wiring pattern to be inspected. Generating analysis coordinates at predetermined wiring length intervals in the signal propagation direction; and obtaining a straight line connecting the analysis coordinate points at the same wiring length from the input points or output points of the + signal line and the − signal line. Calculating the angles formed by the straight line and the + signal line and the − signal line, and comparing the angles; and detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison. And characterized in that:

The present invention is also a storage medium storing a program for inspecting wiring of a printed circuit board, wherein the program is stored on a positive signal line and a negative signal line of a differential signal line which is a wiring pattern to be inspected. Generating analysis coordinates at predetermined wiring length intervals in the signal propagation direction; and obtaining a straight line connecting the analysis coordinate points at the same wiring length from the input points or output points of the + signal line and the − signal line. Calculating the angles formed by the straight line and the + signal line and the − signal line, and comparing the angles; and detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison. Detecting the presence / absence of a phase difference with respect to all the analysis coordinates on the + signal line and the − signal line to obtain the sum of the section lengths of the sections having the phase difference; Sum is a predetermined value A remote small whether the determining, when the sum of the section length of the section of the phase difference is not less than a predetermined value, characterized by comprising a step of outputting a warning.

The present invention is also characterized in that the printed circuit board wiring inspection apparatus further comprises means for detecting a phase difference between the + signal and the-signal of the differential signal line of the wiring pattern to be inspected.

Further, according to the present invention, in a wiring inspection apparatus for a printed circuit board, in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line as a wiring pattern to be inspected,
Means for generating analysis coordinates at a predetermined wiring length interval; obtaining a straight line connecting analysis signal points having the same wiring length from input or output points of the + signal line and the-signal line; And means for calculating the angles formed by the signal lines and comparing the angles, based on the result of the comparison,
Means for detecting the occurrence of a phase difference between the + signal and the-signal.

Further, according to the present invention, in a wiring inspection apparatus for a printed circuit board, in a signal propagation direction on a + signal line and a − signal line of a differential signal line which is a wiring pattern to be inspected,
Means for generating analysis coordinates at a predetermined wiring length interval; obtaining a straight line connecting analysis signal points having the same wiring length from input or output points of the + signal line and the-signal line; And means for calculating the angles formed by the signal lines and comparing the angles, based on the result of the comparison,
Means for detecting the occurrence of a phase difference between the + signal and the-signal, and detecting the presence or absence of the occurrence of a phase difference for all the analysis coordinates on the + signal line and the-signal line, and calculating the sum of the section lengths of the sections having the phase difference. Means for determining, and means for determining whether or not the sum of the section lengths of the section having the phase difference is smaller than a predetermined value, and when the sum of the section lengths of the section having the phase difference is not smaller than a predetermined value. Means for outputting a warning.

According to the present invention, there is provided a wiring pattern generating apparatus for generating a wiring pattern of a printed circuit board, comprising means for inspecting whether or not a phase difference occurs in a differential signal line after generating the wiring pattern. Features. As a result of the inspection, when a section having a phase difference of the differential signal line is long, a means for changing to a wiring pattern in which a section having a phase difference becomes shorter may be further provided.

The wiring pattern of the present invention may be a multilayer wiring pattern.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a flowchart showing the flow of the method for testing a differential signal wiring according to the first embodiment of the present invention.
In the figure, Ldiff indicates an allowable value of the wiring length difference. Also, Lma
x indicates an allowable value of the sum of sections having a phase difference. The values of Ldiff and Lmax are determined in advance. In step 11, the wiring coordinates of the differential signal wiring are extracted. In step 12, the wiring length difference and Ldiff are compared. In step 13, a phase difference is detected.
In step 14, the sum of the section lengths of the sections having a phase difference and Lmax
Compare. In step 15, a warning process is performed. Hereinafter, each step will be described in detail.

In step 11 for extracting the wiring coordinates of the differential signal, positional information (start point, end point, bending) necessary for forming a wiring pattern of the differential signal line is obtained from CAD (Computer Aided Design) data of the wiring board. Point coordinates, layers, etc.).

In step 12 for comparing the wiring length difference and Ldiff, the starting point, the ending point,
Then, the wiring length of the wiring is calculated from the coordinates of the bending point, and the wiring length difference between the signal lines (+ line and-line) forming the pair of the wiring is obtained and compared with Ldiff. Although Ldiff is desirably 0, it is difficult to make the pattern of the paired signals equal in length in the case of high-density mounting. Therefore, the allowable range is set in consideration of the signal propagation speed. According to the inventor's simulation, Ldiff = 1 for a 250 MHz rectangular wave signal.
This is a value equivalent to 0 mm. If the wiring length difference is shorter than Ldiff (16), phase detection 13 is performed, and
If it is longer than diff (17), a warning process 15 is performed.

Next, the phase difference detecting step 13 will be described. FIG. 2 shows a processing procedure of the phase difference detecting step 13. The phase difference detection step 13 includes a function 21 of the wiring pattern, generation of coordinates 22 for analyzing the presence / absence of a phase difference, analysis 23 of the presence / absence of a phase difference, and analysis end determination 24. In the phase difference detection step 13, the presence / absence of a phase difference from the start point to the end point of the wiring pattern to be inspected is checked for each fixed section. Hereinafter, each processing of FIG. 2 will be described in detail.

In the function 21 of the wiring pattern, the wiring pattern to be inspected is converted into a function from the coordinates of the start point, the end point, and the bending point. For example, in the case of the wiring pattern of FIG. 3, the function of the wiring pattern of the + signal line 31 is y = Ys1 (Xs1 ≦ x ≦ Xa1), x = Xa1 (Ya1 ≦ y ≦ Yb1), y = yb1
(Xb1 ≦ x ≦ Xc1), x = Xc1 (Yd1 ≦ y ≦ Yc1), y = Yd1 (Xd1 ≦ x ≦ X
e1). The functions of the wiring pattern of the signal line 32 are as follows: y = Ys2 (Xs2 ≦ x ≦ Xa2), x = Xa2 (Yb2 ≦ y ≦ Ya2), y = yb2
(Xb2 ≦ x ≦ Xc2), x = Xc2 (Yc2 ≦ y ≦ Yd2), y = Yd2 (Xd2 ≦ x ≦ X
e2). In FIG. 3, the x axis is taken in the horizontal direction and the y axis is taken in the vertical direction.

The generation 22 of coordinates for analyzing the presence or absence of a phase difference is performed along the direction in which a signal propagates from the output pin side (the same applies to the input pin side). Therefore, when the wiring pattern is formed of a pattern parallel to the x-axis or the y-axis, the process proceeds while moving the coordinates one by one along the x-axis or the y-axis. Specifically, when the wiring pattern is parallel to the y-axis from the output pin side, the y coordinate is moved by one in the signal propagation direction, and
If it is parallel to the axis, the x coordinate is moved by one in the direction in which the signal propagates, and the coordinates for analyzing the presence or absence of the phase difference (hereinafter, referred to as the analysis coordinates) are changed until they become equal to the end point coordinates (input pin side). Generate sequentially. For example, in the wiring pattern of FIG.
As shown in FIG. 4, the coordinates (Xs1, Ys1) 41 of the output pin and
From (Xs2, Ys2) 42, (Xs1 + 1, Ys1) 43 and (Xs2 + 1, Y
s2) 44, (Xs1 + 2, Ys1) 45 and (Xs2 + 2, Ys2) 46,
..., (Xa1, Ya1) 47 and (Xs2 + n, Ys2) 48, (Xa1, Ya1 +
1) 49 and (Xs2 + n + 1, Ys2) 410,..., (Xs1, Ye1-
1) 411 and (Xs2, Ye2-1) 412, and input pin coordinates (Xe1, Ye1) 413 and (Xe2, Ye2) 414 are sequentially generated.

In step 23 described later, the analysis coordinates (X1,
Since processing is performed for (Y1) and (X2, Y2), this process 2
In step 2, the current analysis coordinates are advanced by one to obtain the next analysis coordinates (X1, Y1) and (X2, Y2), and the analysis coordinates (X1, Y1) and (X2, Y2) are output. Then, steps 22 → 24 → 2
After performing the process 3 and when the process returns to step 22, the previous (X
(1, Y1) and (X2, Y2) are set as the current analysis coordinates, and the current analysis coordinates are advanced by one to obtain and output the next analysis coordinates (X1, Y1) and (X2, Y2). For example, in the examples of FIGS. 3 and 4, when the process proceeds from the step 21 to the step 22, (X1, Y1) = (Xs1, Ys1) and (X2, Y
2) = (Xs2, Ys2), and when the process of steps 22 → 24 → 23 is completed and the next step is to be performed, (X1, Y1) = (Xs1 + 1, Ys
1) and (X2, Y2) = (Xs2 + 1, Ys2), and then in step 22
(X1, Y1) = (Xs1 + 2, Ys1) and (X2, Y2) =
(Xs2 + 2, Ys2), and so on. of course,
First, when the process 22 is entered, all analysis coordinates on the wiring pattern to be processed as shown in FIG.
Output may be performed in order when the process 22 is reached.

The interval between the analysis coordinates for analyzing the presence or absence of the phase difference is not 1 but may be an arbitrary value m. In this case, when a bending point 52 as shown in FIG.
The analysis coordinate next to (Xn1, Yn1) 51 is (Xm1, Ym1) 53 satisfying m1 + m2 = m.

Further, as shown in FIG. 6, in the case of a wiring pattern 61 or a curve 62 which is not parallel to the X and Y axes, the coordinates of the position where the pattern length becomes m64 from the immediately preceding analysis coordinates (Xn, Yn) 63. Is set to the next analysis coordinate (Xm, Ym) 65.

Returning to FIG. 2 again, in the determination 24 of the end of the analysis, it is determined whether or not the analysis of the presence / absence of the phase difference has been completed up to the end point coordinates (input pin side). If the processing has been completed, the processing in FIG. 2 ends, and if not, the flow proceeds to the next step 23.

Next, a method 23 for analyzing the presence or absence of a phase difference will be described. FIG. 7 shows the procedure of the analysis 23 for the presence or absence of a phase difference. FIG. 8 shows an example of wiring when there is no phase difference and when there is a phase difference.

In the analysis 23 of the presence / absence of a phase difference, first, a straight line passing through the analysis coordinates (X1, Y1) and (X2, Y2) output from the step 22 is formed at an angle θ1 formed with respect to two signal lines of the wiring. , Θ2
(Step 71). As shown in FIG. 8, when there is no phase difference, θ1 = θ2, and when there is a phase difference, θ1 ≠ θ2. Thus, the determination of the presence or absence of the phase difference is made by the angles θ1, θ
This is performed by comparing 2 (step 72). If θ1 ≠ θ2 (73), it is determined whether or not this analysis coordinate is the start point of a section having a phase difference (step 74). If it is the start point of the section having the phase difference (75), the occurrence of the section having the phase difference and the start coordinates are recorded (step 7).
6), end the process. If the phase difference is not the start point of a section (712), the analysis of the coordinates is terminated. If it is determined in step 72 that there is no phase difference, (71
1) It is checked whether or not the point of the analysis coordinates is the end point of a section having a phase difference (step 77). If it is the end point (78), the end of the section having the phase difference and the end coordinates are recorded, and the coordinates of the start point and the end point of the section having the phase difference and the coordinates of the inflection point therebetween are recorded. Then, the sum (interconnect length) of the section having the phase difference is calculated (step 79), and the analysis of the coordinates is completed. If it is determined in step 77 that the section having the phase difference does not end (710), the analysis of the coordinates is ended.

FIG. 17 shows an example of wiring for explaining the sum of sections having a phase difference calculated in step 79. The sum of the section having the phase difference is calculated from the coordinates of the start point 176 and the end point 177 of the section having the phase difference and the bending point 178 located therebetween. For example, in the case of the wiring pattern 171 in the upper part of FIG. 17, the wiring length from the start point 176 to the end point 177 is calculated. In the case of the wiring pattern 172 in the lower part of FIG. 17, since there are two sections having a phase difference, the respective wiring lengths L1
The sum L1 + L2 of (174) and L2 (175) is calculated.

Returning to FIG. 2 again, the analysis 23 for the presence or absence of a phase difference as described above is performed while advancing the analysis coordinates, and analysis is performed for all the analysis coordinates on the wiring pattern to be inspected. As a result, the start coordinates and the end coordinates of all the sections having the phase difference and the sum of the wiring lengths of the sections having the phase difference are obtained.

Referring back to FIG. 1, after step 13, step 1
Proceed to 4. In step 14, the sum of the wiring lengths of the sections having the phase difference is compared with a preset length Lmax. Although Lmax is desirably 0, it is preferable to have an allowable range for the same reason as Ldiff.

If it is determined in step 14 that the sum of the wiring lengths in the section having the phase difference is longer than Lmax (18), a warning process (step 1)
5) is performed, and the process ends. If the length is short (including the sum of the wiring lengths of sections having a phase difference = 0) (19), the check of the paired signal lines is terminated.

In the warning processing step 15, the user is informed that there is a wiring length difference and a phase difference between the paired signal lines by text display, signal line highlight display, or warning sound. Also, not only the user, but also a warning signal or the like can be output to notify the system or application software.

The differential signal wiring inspection method described above
A case where the present invention is applied to the analysis of the wiring patterns 96 and 97 in FIG. 9 will be described. Here, Ldiff = 100, Lmax = 10
Set to 0. First, in step 11 of FIG. 1, the wiring coordinates (1000, 1010) 91, (2000, 1010) 910, (2
(000,1110) 911, (2050,1110) 912, (2050,1010) 9
13, (5000,1010) 914, (1000,1000) 92, (4000,10
00) 920, (4000,900) 921, (4050,900) 922, (40
(50,1000) 923 and (5000,1000) 924 are extracted (the numerical values in parentheses are coordinate values). Then, in step 12, the wiring lengths of the wiring 96 and the wiring 97 are calculated from these coordinates by setting the wiring length of the wiring 96 to 4200 and the wiring length of the wiring 97 to 4200.
4200, and it is determined in step 12 that the wiring length difference <Ldiff (16).

Next, a phase difference detecting step 13 is performed. FIG.
In step 13 described above, first, the wiring pattern is converted into a function (step 21). The wiring 96 has y = 1010 (1000 ≦ x ≦ 200
0), x = 2000 (1010 ≦ y ≦ 1110), y = 1110 (2000 ≦ x ≦ 2050),
x = 2050 (1010 ≦ y ≦ 1110), y = 1010 (2050 ≦ x ≦ 5000), wiring 97, y = 1000 (1000 ≦ x ≦ 4000), x = 4000 (900 ≦ y ≦ 100
0), y = 900 (4000 ≦ x ≦ 4050), x = 4050 (900 ≦ y ≦ 1000), y =
Function as 1000 (4050 ≦ x ≦ 5000).

Next, analysis coordinates are generated (step 22).
First, the starting coordinates (1000, 1010) 91 and (100
(0,1000) 92 is used as an analysis coordinate, and the presence or absence of a phase difference is analyzed here (step 23). First, in step 71 of FIG. 7, angles θ1 = 90 ° and θ2 = 90 ° are determined as angles formed by the wiring and a straight line passing through points (1000, 1010) 91 and (1000, 1000) 92 of the analysis coordinates (FIG. 10). . Then, it is determined in step 72 that θ1 = θ2 (711). Thus, in step 77, it is determined whether or not the section where the phase difference is present ends. Since it is not the end of the section where the phase difference is present (710), analysis using this coordinate (step 23)
To end.

Then, in step 22, the next analysis coordinates are generated. As shown in FIGS. 9 and 10, since the wiring is parallel to the x-axis, the x-coordinate is moved in the signal propagation direction (in this case, the x-coordinate is incremented by 1), and the next analysis coordinate (100
(1,1010) 101 and (1001,1000) 102 are generated. Then, an analysis of the presence or absence of a phase difference (step 23) is performed in the same manner. When the analysis coordinates are within the area A93 (FIG. 9) of the portion parallel to the x-axis, as shown in FIG. 10, since there is no phase difference at θ1 = θ2 = 90 °, the start coordinates (1000 , 1
010) The same processing as 91 and (1000, 1000) 92 is repeated.

Then, the analysis coordinates (2000, 1010) 91 in FIG.
When the analysis up to 0 and (2000,1000) 99 is completed, wiring 9
6 is parallel to the y-axis. Therefore, as shown in FIG.
The analysis coordinates of the wiring 96 are (2000, 1011) 111 by moving the y coordinate by one in the signal propagation direction. Since the wiring 97 is parallel to the x-axis, the x-coordinate is moved by one in the signal propagation direction to become (2001, 1000) 112. Then, the presence or absence of the phase difference is analyzed (step 23). First, step 7 in FIG.
1, the angle formed by the lines 96 and 97 and the straight line passing through the analysis coordinates (2000, 1011) 111 and (2001, 1000) 112 is Tanθ1.
= 1/11, Tan θ2 = 11, and it is determined in step 72 that θ1 ≠ θ2 (73). Then, it is determined whether or not the phase difference is the start of a section (step 74). In this case, since the analysis coordinates are the start of the section having the phase difference (75), the analysis coordinates are the occurrence coordinates of the phase difference and the start coordinates of the phase difference occurrence (200
(0,1011) 111 and (2001,1000) 112 are recorded (step 7).
6), the analysis of the presence / absence of a phase difference between the analysis coordinates ends.

Further, coordinates to be analyzed next are generated (step 22). As shown in FIG. 11, the next analysis coordinates (2000, 10
12) 113 and (2002, 1000) 114 also satisfy θ1 ≠ θ2. Then, it is determined whether or not the phase difference is the start of a section (step 74). Since the analysis coordinates are not the start of the section having the phase difference (712), the analysis of the presence or absence of the phase difference of the coordinates (step 23) is completed. Then, the coordinates to be analyzed next are generated (step 22). The analysis coordinates are the area B9 in FIG.
4 while (2000,1012) 113 and (2002,1000) 1
The same processing as in step 14 is repeated.

The analysis coordinates are (4050,1010) 9 in FIG.
8 and (4050,1000) 923, θ1 = θ2 = 90 ° as shown in FIG. Therefore, it is determined in step 72 that there is no phase difference (711). Therefore, it is determined whether or not the section having the phase difference ends (step 77). Since the analysis coordinates are the end (78) of the section having the phase difference, the end coordinates of the section having the phase difference and the end coordinates of the section having the phase difference are (4050, 1010) 98, (4050, 100
0) 923 is recorded (step 79). Further, the wiring length of a section having a phase difference is calculated (step 79). in this case,
The wiring length of the section having a phase difference is represented by the start coordinate (2000, 1011) 111 and the end coordinate (4050,
1010) 98 and the coordinates of the inflection point between them (2000, 1
110) 911, (2050, 1110) 912, (2050, 1010) 913, obtained from (913), and the wiring length of a section having a phase difference = 99 + 50 +
100 + 2000 = 2249 (FIG. 13). Then, the analysis of the presence / absence of a phase difference between the coordinates is completed.

The next analysis coordinates 121 and 122 (FIG. 12)
Since there is no phase difference at θ1 = θ2 = 90 ° (711) and the end of the section with the phase difference is not completed (710), the analysis of the presence or absence of the phase difference at this coordinate is ended. The same processing is repeated, and when the analysis coordinates become equal to the end point coordinates of the wiring pattern, it is determined in step 24 that the analysis is completed, and the phase difference detection step 13 is completed. Then, the sum of sections having a phase difference = 2
249, the sum of sections having a phase difference in step 14>
Lmax is determined, and in step 15, the user or the system or application software is notified of the fact that the section having the phase difference is long by text display, signal line highlight display, a warning sound, or a warning signal.

In the above embodiment, the method of determining the presence or absence of a phase difference by determining whether or not θ1 = θ2 is used. In this case, as shown in FIG. But it becomes a warning target. For this reason, the presence or absence of a phase difference may be determined by giving an allowable range of the phase difference and determining | θ1−θ2 | <θ0 (θ0 is a predetermined value). In the present embodiment,
The sum of the sections having the phase difference is calculated at the time of analyzing the end coordinates of the section having the phase difference, but may be obtained by integrating at the time of the analysis at the section having the phase difference.

Next, a second embodiment of the present invention will be described. The first embodiment is directed to a single-layer wiring pattern on a wiring board. On the other hand, in a wiring board having a plurality of wiring layers, the signal propagation speed differs depending on the wiring layer. For this reason, in order to match the phases of the paired signals, when the wiring patterns are switched, it is desirable that the places where the paired signal layers are switched be as close as possible. Therefore, in a second embodiment described below, a method of checking wiring of a pair of signals when wiring is performed on a wiring board having a plurality of wiring layers will be described.

FIG. 15 shows a flow of steps of a method for inspecting differential signal wiring according to the second embodiment of the present invention. The inspection method includes a step 11 of extracting wiring coordinates of a paired signal and a step 12 of comparing a wiring length difference with a preset length Ldiff.
A step 151 of determining whether or not the layers are switched; a step 152 of determining whether the distance of the place where the pair of two-layer layers are switched is shorter than a predetermined distance Lv; 13, a step 14 of comparing the sum of sections having a phase difference with a preset length Lmax, and a step 15 of performing a warning process.

Steps 11 and 12 are the same as the steps of the same numbers in FIG. However, in the present embodiment, since wirings over multiple layers are to be inspected, the wiring coordinates are represented by three-dimensional xyz coordinates, and the wiring length is also a length in the xyz coordinate system.

The step 151 of judging whether or not the layers have been exchanged judges whether or not the layers of the two wiring patterns have been exchanged. If there is no layer exchange (153), the first
The phase difference detection 13 is performed in the same manner as in the method of the embodiment.
If the layers are exchanged (154), it is determined in step 152 whether or not the distance of the place where the layers of the two wires to be exchanged are shorter is shorter than a preset distance Lv. The distance between the positions where the layers are switched is a preset value Lv
It is determined whether or not the distance is shorter. It is desirable that the distance at which the layers of the two lines forming a pair are switched be the wiring pattern interval of two signals, but the allowable range is determined by the pattern interval and the signal propagation speed in each wiring layer. If the distance of the place where the layers of the two lines forming the pair are switched is shorter than the distance Lv (155), the phase difference detection 13 is performed in the same manner as in the method of the first embodiment. Do.

A phase difference detecting step 13, a step 14 for comparing the sum of the section lengths having a phase difference with Lmax, and a warning processing step 1
5 is a process similar to the process of the same number in FIG. In step 15 of performing the warning process, in addition to warning that the wiring length difference is large and that the section having the phase difference is long, there is a case that a warning is given that the place where the layers of the two wires are exchanged is distant.

In the upper part of FIG. 16, the difference between the two wiring lengths is Ldiff.
There is a smaller location 162 where the layers are switched, and the distances L1 (163) and L2 (164) of the switched locations are L
14 shows a wiring pattern 161 smaller than v. In the wiring pattern 161, it is assumed that the portion indicated by the solid line and the portion indicated by the dotted line are wired in different layers. When the wiring pattern 161 is inspected according to the procedure shown in FIG. 15, it is determined that the wiring length difference is smaller than Ldiff in the step 12 of comparing the wiring length difference with a preset length Ldiff (16), and the layers are switched. In step 151 for determining whether or not the layers are switched (154), it is determined whether the distance of the place where the two-line layers are switched is shorter than a preset distance Lv.
At 52, it is determined that the value is smaller than Lv (155), and the phase difference detecting step 13 is performed. After that, the same processing as in the first embodiment is performed.

In the middle part of FIG. 16, the wiring length difference between the two lines is Ldiff.
There is a wiring pattern 164 that is smaller and has a place 162 where layers are switched, and the distance L3 (165) of the place where the layers are switched is larger than Lv. In the wiring pattern 164, it is assumed that the part shown by the solid line and the part shown by the dotted line are wired in different layers. When inspecting this wiring pattern 164 in the procedure of FIG. 15, the wiring length difference and the preset length L
In the step of comparing diff, it is determined that the wiring length difference is smaller than Ldiff (16), and in the step 151 of determining whether or not the layers are replaced, it is determined that the layers are replaced (15).
4) In step 152 of determining whether the distance of the place where the wiring layers are switched is shorter than a preset distance Lv, it is determined that the distance is larger than Lv (156). Then, in step 15, 2
Warns that the places where the line layers change places are far apart.

The wiring inspection methods of the first and second embodiments can be embodied by a program that executes processing according to the above inspection procedure. Also, a wiring inspection device can be embodied by mounting a program for executing the above inspection procedure on a computer and operating the computer.

Next, an example in which the wiring inspection method for differential signals of the present invention is applied to a wiring pattern generating apparatus will be described. FIG.
5 is a flowchart illustrating a pattern generation method of the wiring pattern generation device. The generation of the wiring pattern by the wiring pattern generation apparatus includes a wiring pattern generation step 201, a step 202 of inspecting the wiring of the differential signal, and a step 204 of changing the wiring pattern. In step 202, the differential signal wiring according to the present invention is inspected for the wiring pattern generated in step 201. For example, the inspection method of the above embodiment may be applied. If NG, that is, a warning occurs in step 202 (206), the corresponding wiring pattern is changed in step 204. In the change of the wiring pattern in the step 204, for example, when the section having the phase difference of the differential signal line is long, the section having the phase difference is changed to a wiring pattern that shortens the section.

[0052]

As described above, according to the present invention,
With respect to a wiring pattern of a single-layer or multi-layer printed circuit board, the phase difference of the differential signal wiring can be detected, and a board with less radiation noise can be produced. By applying the present invention to the wiring pattern generation device, it is possible to automatically generate a wiring pattern in which a section having a phase difference between the differential signal lines is shortened.

[Brief description of the drawings]

FIG. 1 is a flowchart of a differential signal wiring inspection method according to the present invention.

FIG. 2 is a flowchart showing a phase difference detecting step.

FIG. 3 is a diagram for explaining functioning of a wiring pattern;

FIG. 4 is a diagram illustrating a method of generating analysis coordinates.

FIG. 5 is a diagram illustrating a method of generating analysis coordinates at a bending point.

FIG. 6 is a view for explaining a method of generating analysis coordinates in oblique and curved wiring patterns;

FIG. 7 is a flowchart illustrating an analysis process of the presence or absence of a phase difference;

FIG. 8 is a view for explaining a method for determining the presence or absence of a phase difference;

FIG. 9 is a diagram showing a wiring pattern to be inspected;

FIG. 10 is a view for explaining a method for determining the presence or absence of a phase difference in a region A;

FIG. 11 is a view for explaining a method for determining the presence or absence of a phase difference in a region B;

FIG. 12 is a view for explaining a method for determining the presence or absence of a phase difference in a region C;

FIG. 13 is a view for explaining the length of a section having a phase difference;

FIG. 14 is a diagram illustrating generation of a phase difference.

FIG. 15 is a flowchart of the differential signal line inspection method according to the second embodiment;

FIG. 16 is a diagram showing a wiring pattern in which layers are exchanged.

FIG. 17 is a view for explaining the sum of sections having a phase difference;

FIG. 18 is a view for explaining a phase difference between a + line and a − line.

FIG. 19 is a diagram showing a relationship between a section having a phase difference and radiation noise.

FIG. 20 is a flowchart illustrating a pattern generation method.

[Explanation of symbols]

11-19: Differential signal wiring inspection step, 21-24: Phase difference detection step, 31 ... + signal line, 32 ...- signal line, 41
~ 42 ... coordinates of output pins, 43 to 49 ... coordinates of bending points,
410 to 412: coordinates of a bending point; 413 to 414: coordinates of an input pin; 51: previous analysis coordinates (Xn1, Yn1);
Bending point, 53 ... The next analysis coordinates (Xm1, Ym1), 61 ...
Wiring patterns 61 and 62 that are not parallel to the X and Y axes Curve wiring patterns 63 63 Previous analysis coordinates (Xn, Yn), 64
... pattern length m, 65 ... next analysis coordinates (Xm, Ym), 71
７７77,710: Analysis step for the presence or absence of a phase difference, 81: Analysis coordinates (X1, Y1), 82: Analysis coordinates (X2, Y2), 83: Analysis coordinates
A straight line passing through (X1, Y1) and (X2, Y2), 84: angle θ1 formed by the wiring and the analysis coordinates, 85: angle θ2 formed by the wiring and the analysis coordinates,
93 ... Area A, 94 ... Area B, 95 ... Area C, 96, 9
7: wiring pattern, 98, 99: analysis coordinates, 91, 91
0-914 ... wiring coordinates, 92, 920-924 ... wiring coordinates, 101, 102 ... analysis coordinates, 98, 99 ... analysis coordinates, 111, 112, 113, 114, 121, 122
... Analytical coordinates, inspection process for replacing 151-155 layers, 1
61: wiring pattern, 162: place where layers are switched, 1
63: distances L1 and 164 of the places to be replaced L2 and 165 ... distances of the places to be replaced
171: wiring pattern, 172: wiring pattern, 173
... The length of a section with a phase difference, 174... The length L1 of the section with a phase difference, 175.
76 ... Start point, 177 ... End point, 178 ... Bend point, 20
1, 202, 205 to 206: wiring pattern generation step.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yokota et al. 810 Shimoimaizumi, Ebina-shi, Kanagawa F-term in PC Division, Hitachi, Ltd. F-term (reference) 2G014 AA10 AB59 AC09

Claims (10)

[Claims] 1. A wiring inspection method for a printed circuit board, comprising detecting a phase difference between a + signal and a-signal of a differential signal line of a wiring pattern to be inspected. 2. A wiring inspection method for a printed circuit board, wherein analysis coordinates are generated at predetermined wiring length intervals in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line as a wiring pattern to be inspected. And calculating a straight line connecting the points of the analysis coordinates having the same wiring length from the input points or the output points of the + signal line and the − signal line, and calculating the angles formed by the straight line and the + signal line and the − signal line, respectively. A wiring inspection method, comprising: calculating and comparing angles thereof; and detecting occurrence of a phase difference between a + signal and a − signal based on a result of the comparison. 3. A wiring inspection method for a printed circuit board, wherein analysis coordinates are generated at predetermined wiring length intervals in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line as a wiring pattern to be inspected. And calculating a straight line connecting the points of the analysis coordinates having the same wiring length from the input points or the output points of the + signal line and the − signal line, and calculating the angles formed by the straight line and the + signal line and the − signal line, respectively. Calculating and comparing the angles; detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison; Detecting the presence or absence of a phase difference, obtaining the sum of the section lengths of the sections with a phase difference, and determining whether the sum of the section lengths of the sections with a phase difference is smaller than a predetermined value; With the phase difference When the section length sum between is not less than the predetermined value, wiring inspection method characterized by comprising the step of outputting a warning. 4. A storage medium storing a program for inspecting wiring of a printed circuit board, the program comprising: a signal propagation on a + signal line and a − signal line of a differential signal line which is a wiring pattern to be inspected. Generating analysis coordinates at predetermined wiring length intervals in the direction, obtaining a straight line connecting the points of the analysis coordinates having the same wiring length from the input points or output points of the + signal line and the-signal line, and The method includes the steps of calculating angles formed by the + signal line and the − signal line and comparing the angles, and detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison. A storage medium characterized by the following. 5. A storage medium storing a program for inspecting wiring of a printed circuit board, the program comprising: a signal propagation on a + signal line and a − signal line of a differential signal line which is a wiring pattern to be inspected. Generating analysis coordinates at predetermined wiring length intervals in the direction, obtaining a straight line connecting the points of the analysis coordinates having the same wiring length from the input points or output points of the + signal line and the-signal line, and Calculating each of the angles formed by the + signal line and the − signal line, and comparing the angles; detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison; Detecting the presence or absence of a phase difference with respect to all the analysis coordinates on the + signal line and the − signal line to obtain the sum of the section lengths of the sections having the phase difference; Less than value Determining whether, when the sum of the section length of the section of the phase difference is not less than the predetermined value, the storage medium characterized by comprising a step of outputting a warning. 6. An apparatus for inspecting wiring of a printed circuit board, comprising means for detecting a phase difference between a + signal and a-signal of a differential signal line of a wiring pattern to be inspected. 7. A printed circuit board wiring inspection apparatus, wherein analysis coordinates are generated at predetermined wiring length intervals in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line which is a wiring pattern to be inspected. Means for obtaining a straight line connecting points of analysis coordinates having the same wiring length from input points or output points of the + signal line and the-signal line, and determining angles formed by the straight line and the + signal line and the-signal line, respectively. A wiring inspection apparatus comprising: means for calculating and comparing angles thereof; and means for detecting occurrence of a phase difference between a + signal and a − signal based on a result of the comparison. 8. A wiring inspection apparatus for a printed circuit board, wherein analysis coordinates are generated at predetermined wiring length intervals in a signal propagation direction on a positive signal line and a negative signal line of a differential signal line as a wiring pattern to be inspected. Means for obtaining a straight line connecting points of analysis coordinates having the same wiring length from input points or output points of the + signal line and the-signal line, and determining angles formed by the straight line and the + signal line and the-signal line, respectively. Means for calculating and comparing those angles; means for detecting the occurrence of a phase difference between the + signal and the − signal based on the result of the comparison; Means for detecting the presence or absence of occurrence of a phase difference, obtaining a sum of section lengths of sections having a phase difference, and means for determining whether or not the sum of section lengths of the sections having a phase difference is smaller than a predetermined value; The sum of the section lengths of the section having the phase difference is When not smaller than the value, wiring inspection apparatus characterized by comprising a means for outputting a warning. 9. A wiring pattern generating apparatus for generating a wiring pattern on a printed circuit board, comprising:
A wiring pattern generation device, comprising: means for checking whether or not a phase difference occurs in a differential signal line. 10. The wiring pattern generating apparatus according to claim 9, wherein, as a result of the inspection, when a section having a phase difference of the differential signal line is long, the section is changed to a wiring pattern having a shorter section having a phase difference. A wiring pattern generation device, comprising: