JPS6092695A - High density printed wiring method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a high-density printed wiring method using random through holes with small land diameters for high-density printed wiring.

[Technical background of the invention and its problems]

In recent years, there has been an increasing demand for higher density printed wiring boards. Therefore, in order to increase the density of printed wiring, two
Two methods are being considered.

■ By narrowing the conductor width of the signal line.

Increase the maximum number of signal lines that can be arranged between l grids (for example, 0.1 inch).

■ Increase the maximum number of signal lines that can be placed between l grids by reducing the land diameter of random through holes.

However, printed wiring boards made using this method have an extremely large number of random through holes with small land diameters that require advanced manufacturing technology. A (Design Au
tomation) In automatic wiring by program,
Following the wiring process steps In the step of 9 through-hole deletion processing, consideration is given to reducing as much as possible random through holes placed during thin wiring by improving the wiring/4' turn route. however.

Even with such pressure, there were many random through holes with small land diameters, which inevitably led to a decrease in manufacturing yield.

[Purpose of the invention]

This invention has been made in view of the above circumstances, and its purpose is to provide a high-density printed wiring method that can increase the density of printed wiring without sacrificing the manufacturing yield.

[Summary of the invention]

In this invention, K is used to increase the density of printed wiring.

Fine wiring is performed using random through holes with a small allowable shield diameter. and.

This invention uses a random through hole that allows the land diameter to be increased on the premise that after this fine wiring, the turn of the wiring arm is changed.

Change the wiring pattern around the random through hole and change the random through hole to a through hole with a larger land diameter. I made this so that I could grow it.

[Embodiments of the invention]

FIG. 1 shows the hardware configuration of a computer system according to an embodiment of the present invention. In the same figure, a CPU designated by the reference numeral 10 forms the center of the system, and has a main memory 2.
According to the automatic wiring program 21 stored in o, automatic wiring processing of the printed wiring board is performed using the design file (database) 31 stored in the external storage device 30. It should be noted that the human output control device designated by the reference numeral 4o performs data input/output control between input/output devices such as the external storage device 30 and the CPUJO (main memory Z(7)).

FIG. 2 shows a portion of a high density printed wiring board on which automatic wiring is applied. In the same figure, the basic lattice indicated by reference numeral 51 is
Indicates the minimum degree to which a pin or random through-hole will be placed. A quasi-lattice 52 obtained by dividing the basic lattice 6 indicates lines in which a wiring pattern (conductor pattern of a signal line) can be arranged. In this way, the printed wiring board is represented by the basic lattice 51 and the quasi-lattice 52.

In an automatic wiring process based on the automatic wiring program 21, the CPUJ O first processes the basic grid 61. as shown in the flowchart of FIG. Perform fine wiring (fine wiring) using the quasi-grid 62 (step 77"8J). That is,
CPUJ17 is.

For the image of the printed wiring board in Fig. 2, determination of basic grid points for pin arrangement, determination of basic grid points for random through small arrangement, wiring AI turn arrangement using quasi-lattice 52, etc. 1 knowledge Perform wiring processing. These processing results are stored in the design file 31 of the external storage device 30. Next, CPUI O removes unnecessary random through poles by improving the wiring AI pattern route *-
A file deletion process is performed (step s2).

In the conventional automatic wiring process, the process ends at step s2.

FIG. 4 shows a portion of a printed wiring board obtained by a conventional automatic wiring process (i.e., the process of steps 81 and 82 of the flowchart shown in FIG. 3). In the same figure, 61. ~61° is the pin whose placement was determined in step 87, 62@, 62.
is a random through hole with a small land diameter determined in steps 8i and 8z (mt frame through hole)
It is. Also, 631-63. is a horizontal pattern (conductor pattern) on a layer that allows horizontal patterns, 64. ~6
41° is a vertical pattern (conductor pattern) on the layer that allows four turns in the vertical direction. These horizontal/4 turns (l
iJk (k=1.2...) and vertical mother turn 64
gCI=1.2...) corresponds to the position of the quasi-lattice 52 (furthermore, the basic lattice 5) shown in FIG.

Note that the following four conditions are applied to the automatic wiring in this embodiment.

■ Basic grid 51. as wiring red route. A quasi-lattice 62 can be used.

■ The bin 611 (1=1.2...) and the random through hole 623 (j=J, Z...) are the basic lattice 51
is located on the lattice point (basic lattice point).

(2) By arranging the bins 611, two quasi-lattices 52 between the basic lattices 51 become unusable.

(2) By arranging the random through holes 623, one quasi-lattice 52 between the basic lattices 51 becomes unusable.

Under the above conditions, according to the procedure of the conventional method, thin wiring using random through holes with small land diameters (step S1) and unnecessary through holes are deleted (step 8z)? ：I want to do it.

As shown in FIG. 4, there may be areas where the printed wiring density is low around the random through hole (in this example, the random through hole 62I).

Therefore, in this embodiment, the automatic wiring process is not completely terminated in step S2, but the process continues to detect the above-mentioned locations, and by partially changing the wiring pattern, a random through wire with a small land diameter is created. The hole is changed to a random through hole with a large land diameter (specifically, the same land diameter as the bottle 611). This change process will be described in detail below.

CPUJ (7 is the design file 3 in the external storage device 30 when the process of deleting unnecessary through holes in step S2 is performed.
) and take out the U-da--Ho-0 position 1'N@\ (with small land diameter) arranged on (the basic lattice points of) the printed wiring board (step 83). Next, CPUJ O
teeth.

The extraction of the position information of all the random through holes has already been completed, and it is determined whether or not there are no new random through holes to be extracted (step 84). Now, the position information of the random through hole 62j is extracted in the process of step 83, and therefore the process of step 8
It is assumed that the determination result in step 4 is NO.

In this case, the CPU 10, based on the position information of the random through hole 623 extracted in the process of step S3,
The wiring information around the random through hole 623 is extracted from the design file 3 in the external storage device 30 (step 85).

Here, the wiring information around the random through hole 623 refers to the bins and random through holes placed around the random through hole 623 (for example, the basic lattice that shares the basic lattice point where the random through hole 621 is placed). , and information on the number and position of wiring patterns (conductor patterns) arranged around the random through hole ezz.

When the CPUJ O executes step S5, it obtains the wiring information around the random through hole 623 obtained in step 85, as well as identification information such as the width of the wiring pattern, the minimum interval between patterns, and the size of the bin and random through hole. , and the aforementioned conditions (1) and (2), it is determined whether the random through hole 62j can be changed to a random null hole with a larger land diameter (the same land diameter as the bottle 611) (step f86). This semi-determination is performed with the exception of changing the wiring pattern (its placement position) around the random through hole 62j. Note that there are cases where changing the wiring pattern is not safe. For example, random through hole 62. If the land diameter cannot be increased even if the wiring pattern around one is changed as shown in (this is because four vertical patterns 64v to 64m are running within the basic lattice on the right side of the random through hole 62), The determination result in step S6 is NO. This station building.

Return to step 83. On the other hand, random through hole 62
．． By changing the surrounding wiring pattern (in this example, moving the horizontal patterns 63...636 downward in the diagram by one quasi-grid), the land diameter can be changed without changing the turn (or wiring). If it is possible to increase
The determination result at step 86 is yl! It becomes an is judgment. In this case, CPU10 is 1, for example, random through hole 6
2. In this case, the horizontal nine turns 6:i, , 63 . shown in FIG. 4 can be used to greatly change the land diameter. is moved downward in the diagram by one quasi-grid (step sy)
. Next, the CPU 10 replaces the random through hole 62m with a small land diameter with the random through hole 8 with a large land diameter (same land diameter as the pin 6Ji) as shown in FIG.
1!2 Random through hole) Change 70WC. In addition, in FIG. 5, the horizontal no-turns indicated by reference numerals 71 and 72 correspond to the horizontal pattern 63. shown in FIG. ．． This is a noe turn obtained by moving 63. as described above. CPU
When l0 performs the process of step S8, it returns to step S.
Execute 3.

In this way, the wiring around one of the random through holes with a small land diameter that has been placed once has four turns (
A through hole whose land diameter can be increased by changing the arrangement position 1t)t (or by changing the current state) is selectively changed to a random through hole with a large land diameter. Then, the determination result in step S4 is Y.
When it comes to ES determination, that is, when it is determined that the extraction of position information of all random through holes has already been completed,
The automatic wiring process ends.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to manufacture #a without reducing the printed wiring density.

The number of random through holes with small land diameters that are difficult to inspect can be reduced as much as possible. That is.

According to this invention, it is possible to increase the density of printed wiring without sacrificing manufacturing yield.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a computer system according to an embodiment of the present invention, FIG. FIG. 4 is a flowchart showing the procedure of automatic wiring processing realized by the computer system shown in the figure. FIG. 4 shows an example of the wiring result obtained by the conventional automatic wiring processing procedure. FIG. 5 is a diagram showing an example of a wiring result according to the flowchart of FIG. 3. 10...CPU, 31...Design file, 57...
・Basic lattice, 52... quasi-lattice, 621. 62! *〜
・First random through hole, 631-63. . 71.12...Horizontal pattern, 64. ~-641°...
Vertical arm turn, 7111...2nd random through hole. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Masaru Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] Determination of pin arrangement basic lattice points, determination of first random through hole arrangement basic lattice points, and wiring node using quasi-lattice
After fine wiring processing such as turn arrangement, a first step of deleting the unnecessary first random through hole by improving the route of the wiring pattern, and a first step of removing the first random through hole whose placement is determined in this first step. A second step of obtaining peripheral wiring information, and based on the above-mentioned wiring information obtained in this second step, by changing the wiring arm turn, the corresponding first random through hole is changed from the through hole to the shield diameter. A third step of determining whether or not it can be changed to a larger second random through hole, changing the wiring i4 turn according to the judgment result in the third step, and changing the corresponding first random through hole to the second random through hole. and a fourth step of changing to two random through holes.