JP2003207535A - Printed circuit board inspection method and printed circuit board inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board inspection method capable of preventing wrong determination. <P>SOLUTION: When a disconnection on wiring 7 is produced near a back terminal 4 of the wiring 7 for connecting electrically the front and the back of the printed circuit board 5, the disconnection can not be detected hitherto, because a measuring needle 15 can not be brought into contact with the back terminal 4. On this account, a metal stage 19 is connected to the back terminal 4. When inspecting the wiring 7, the measuring needle 15 is brought into contact with a surface terminal 3 of the wiring 7. When the disconnection on the wiring 7 is generated near the back terminal 4, the electric capacity to be measured is approximately equal to a combined electric capacity of an electric capacity C3 and an electric capacity C4, but is smaller than an expected value as much as an electric capacity C5 between the stage 19 and a counter electrode 11, and hereby generation of the disconnection can be detected. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board inspection method and a printed circuit board inspection apparatus, and more particularly to a printed circuit board inspection method for determining the quality of wiring provided on a printed circuit board.

[0002]

2. Description of the Related Art As a method of inspecting a printed wiring board, there is an electric capacity measuring method which judges the quality of the wiring to be inspected by utilizing the magnitude of the electric capacitance generated between the wiring to be inspected and an electrode facing it.

A conventional printed circuit board inspection method using this capacitance measuring method will be described with reference to the drawings. Figure 2
FIG. 6 is a diagram showing a configuration of a conventional printed circuit board inspection device.
In FIG. 2, a printed circuit board inspecting apparatus for determining acceptability of a wiring to be inspected by a conventional printed circuit board inspecting method includes a capacitance meter 10, a counter electrode 11, a acceptability determining unit 12, a acceptability determining condition storage unit 13, Good / bad display 14 and measuring needle 1
5 and a measuring arm 16.

The counter electrode 11 is installed facing the printed circuit board 5 and is made of a metal plate having a size sufficient to cover the printed circuit board 5. Measuring needle 15 is measuring arm 16
Is connected to the capacitance meter 10 via the counter electrode 1
1 is also electrically connected to the capacitance meter 10.

On the printed circuit board 5 to be inspected, an electric wiring 6 composed of a lower layer wiring 20 and an upper layer wiring 21 is provided.
And an electric wiring 7 which is composed of a lower layer wiring 22 and an upper layer wiring 23 and electrically connects the front and back of the printed circuit board 5.

Here, when the quality of the electric wiring 6 provided on the printed circuit board 5 is determined, the measuring needle 15 attached to the measuring arm 16 is placed on the surface of the printed circuit board 5 as the terminal 1 or the terminal on the electric wiring 6. Contact 2. And
An electric capacitance between the counter electrode 11 arranged to face the electric wiring 6 and the electric wiring 6 is measured by the electric capacitance meter 10.

After that, the pass / fail judgment unit 12 causes the capacitance meter 1 to
The electrical capacitance value measured by 0 is compared with the theoretical electrical capacitance value (expected value) between the electrical wiring 6 and the counter electrode 11 stored in the quality determination condition storage unit 13, and the electrical wiring 6 is compared.
The quality of is judged. When the measured value is smaller than the expected value, the quality determination unit 12 determines that the disconnection is defective, and displays the determination result on the quality display unit 14.

If the measuring wire 15 is brought into contact with the terminal 1 or the terminal 2 when the disconnection failure does not occur in the electric wiring 6,
Each of the electric capacities measured by the electric capacity meter 10 is the lower layer wiring 20 and the counter electrode 11 which constitute the electric wiring 6.
The electric capacity C1 between them and the upper layer wiring 2 which constitutes the electric wiring 6
1 and a capacitance C2 between the counter electrode 11 and a combined capacitance. Since this is equal to the expected value, the pass / fail judgment unit 12
The electric wiring 6 is determined to be non-defective.

On the other hand, for example, the lower layer wiring 20 and the upper layer wiring 21
When the measuring needle 15 is brought into contact with the terminal 1 when there is a disconnection defect, only the electric capacitance C1 between the lower layer wiring 20 and the counter electrode 11 is measured, and the measuring needle 15 is brought into contact with the terminal 2. In this case, only the electric capacitance C2 between the upper layer wiring 21 and the counter electrode 11 is measured, and in both cases, it is smaller than the combined electric capacitance of the electric capacitance C1 and the electric capacitance C2, which is the expected value, and therefore the pass / fail judgment unit 12 Can detect that the wire is defective.

When the quality of the electric wiring 7 provided on the printed board 5 is determined, the measuring needle 15 attached to the measuring arm 16 is brought into contact with the terminal 3 on the electric wiring 7 located on the surface of the printed board 5. . Then, the electric capacitance between the counter electrode 11 arranged to face the electric wiring 7 and the electric wiring 7 is measured by the electric capacitance meter 10.

When the electric wire 7 has no disconnection defect, the measuring needle 15 is brought into contact with the terminal 3 and the electric capacitance meter 1
The electric capacitance measured by 0 is a combination of the electric capacitance C3 between the lower layer wiring 22 and the counter electrode 11 forming the electric wiring 7 and the electric capacitance C4 between the upper layer wiring 23 and the counter electrode 11 forming the electric wiring 7. It becomes electric capacity. Since this is equal to the expected value (theoretical electric capacity between the electrical wiring 7 and the counter electrode 11) stored in the quality determination condition storage unit 13, the quality determination unit 12 determines that the electrical wiring 7 is a good product.

On the other hand, for example, the lower layer wiring 22 and the upper layer wiring 23
When the measuring needle 15 is brought into contact with the terminal 3 when there is a disconnection defect between them, only the electric capacitance C4 between the upper wiring 23 and the counter electrode 11 is measured, and the expected electric capacitances C3 and C4 are obtained. Since the combined capacitance is smaller than the combined capacitance of No. 3, the pass / fail judgment unit 12 can detect a disconnection defect.

[0013]

In such a conventional printed circuit board inspection method, when the quality of the electric wiring 7 extending from the front to the back of the printed circuit board 5 is determined, the measuring needle 15 is placed on the surface of the printed circuit board 5 as described above. The capacitance can be measured by contacting the upper terminal 3. However, although not shown in FIG. 2, since a stage for supporting the printed circuit board 5 is usually installed for inspection, the rear surface connector pin 4 (terminal) on the electric wiring 7 located on the rear surface of the printed circuit board 5 is installed.
The measuring needle 15 cannot be brought into contact with, and the capacitance from the rear surface connector pin 4 cannot be measured.

Therefore, when a disconnection portion existing in the electric wiring 7 occurs in a portion very close to the back surface connector pin 4, the electric wiring 7 and the counter electrode which are measured by bringing the measuring needle 15 into contact with the terminal 3 The capacitance between 11 is almost equal to the combined capacitance of the capacitance C3 and the capacitance C4, and there is almost no difference from the expected value, which is within the non-defective range of the expected value. There is a problem that the electric wiring 7 is mistakenly judged as a good product in spite of the disconnection defect.

As for the electrical wiring 6, the terminal 1 is only required to be measured by bringing the measuring needle 15 into contact with one terminal.
Alternatively, the electric wire 6 may be determined to be a good product even if a disconnection occurs in a portion very close to the terminal 2, and therefore the measurement needle 15 is also brought into contact with the other terminal to perform the measurement. There must be. That is, the electrical wiring 6
If the measurement was not performed from both ends of each of the above, it was not possible to reliably determine the quality.

A first object of the present invention is to provide a printed circuit board inspecting method and a printed circuit board inspecting apparatus capable of surely making a pass / fail judgment without performing measurement from both terminals on a wiring provided on the printed circuit board. It is to be.

A second object of the present invention is to provide a printed circuit board inspection method and a printed circuit board inspection device capable of preventing an erroneous judgment at the time of judging the quality of the wiring electrically connecting the front and back of the printed circuit board. Is.

[0018]

A first printed circuit board inspecting method according to the present invention is a printed circuit board inspecting method for determining the quality of wiring provided on a printed circuit board. A conductor is connected to a terminal on the wiring while being arranged, the electric capacitance between the wiring to which the conductor is connected and the counter electrode is measured, and the pass / fail judgment is made based on the measured electric capacitance. It is characterized by doing so.

In the first printed circuit board inspection method, the wiring is a wiring extending over the front and back surfaces of the printed circuit board, and the conductor is connected to terminals on the wiring located on the back surface of the printed circuit board. Is characterized by.

A second printed circuit board inspection method according to the present invention uses a measuring needle for electrically connecting to a wiring provided on the printed circuit board and a counter electrode arranged to face the printed circuit board. A printed circuit board inspection method for determining the quality of the wiring, wherein a conductor is connected to a terminal on the wiring, the measuring needle is brought into contact with the wiring, and the wiring and the counter electrode to which the conductor is connected. It is characterized in that the electric capacity between the two is measured, and the quality judgment is performed based on the measured electric capacity.

Further, in the second printed circuit board inspection method, the conductor is connected to one terminal on the wiring, and the measuring needle is in contact with the other terminal on the wiring.

Further, in the second printed circuit board inspection method, the wiring is a wiring extending over the front and back of the printed circuit board, and one terminal on the wiring is a terminal located on the back surface of the printed circuit board. The other terminal on the wiring is a terminal located on the surface of the printed circuit board.

Further, in the first and second printed circuit board inspection methods, a stage for supporting the printed circuit board is used as the conductor.

In the first and second printed circuit board inspection methods, the measured electric capacity and the theoretical electric capacity between the wiring to which the conductor is connected and the counter electrode are set. It is characterized in that the quality judgment is made by comparison.

The printed circuit board inspection device according to the present invention is a printed circuit board inspection device for determining the quality of wiring provided on a printed circuit board, wherein a conductor is connected to a terminal on the wiring and the printed circuit board is connected to the printed circuit board. Capacitance measurement for measuring the capacitance between the counter electrode and the counter electrode, which are arranged to face each other, the measurement needle, and the measurement needle contacting the wiring to connect the conductor to the wiring and the counter electrode. Means and a quality determination means for performing the quality determination based on the electric capacity measured by the electric capacity measuring means.

In the printed circuit board inspection apparatus, the conductor is connected to one terminal on the wiring, and the measuring needle is in contact with the other terminal on the wiring.

Further, in the printed circuit board inspection device, the wiring is a wiring extending over the front and back surfaces of the printed circuit board, and one terminal on the wiring is a terminal located on the back surface of the printed circuit board, and on the wiring. The other terminal is a terminal located on the surface of the printed circuit board.

Further, the printed circuit board inspection apparatus includes a stage for supporting the printed circuit board, and the stage is used as the conductor.

In the printed circuit board inspecting device, the quality determining means may include the measured capacitance and
It is characterized in that the quality judgment is performed by comparing the theoretical capacitance between the wiring to which the conductor is connected and the counter electrode.

The operation of the present invention is as follows. By connecting a conductor to the terminal on the wiring to be inspected, the electric capacitance between the wiring to which the conductor is connected and the counter electrode is measured. Then, the quality of the wiring to be inspected is determined based on the measured electric capacity. As a result, in the past, it was not possible to reliably perform the pass / fail judgment without performing measurement from both terminals on the wiring to be inspected, but in the present invention, the measurement from the terminal to which the conductor is connected can be performed. It becomes possible to reliably perform the pass / fail determination without performing the determination.

When the wiring to be inspected is a wiring extending to the front and back of the printed circuit board, the conductors connected to the terminals on the wiring to be inspected are terminals located on the back surface of the printed circuit board (back surface terminals). By connecting, it is possible to surely perform the pass / fail determination without performing the measurement from the back surface terminal, and it is possible to prevent the erroneous determination due to the inability to perform the measurement from the back surface terminal.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a printed circuit board inspection apparatus according to an embodiment of the present invention, and the same portions as those in FIG. In FIG. 1, a printed circuit board inspecting apparatus for determining the quality of a wiring to be inspected by using a printed circuit board inspecting method according to an embodiment of the present invention includes an electric capacitance meter 10, a counter electrode 11, a quality determination unit 12, and a quality determination. The condition storage unit 13, the pass / fail display unit 14, and the measuring needle 15
And a measurement arm 16, and further has a metal stage 19.

The metal stage 19 supports the printed circuit board 5 for inspection, and is connected to the back surface connector pins 4 of the printed circuit board 5. Further, among the expected values stored in the quality determination condition storage unit 13, the quality determination unit 1
The expected value compared with the electric capacitance value measured by the inspection of the electric wiring 7 in 2 is the combined electric capacity of the electric capacity C3 and the electric capacity C4 in the conventional example shown in FIG.
The theoretical capacitance between the counter electrode 11 and the counter electrode 11), but in the present embodiment, the capacitance C3, the capacitance C4, and the capacitance C5.
(Electrical capacitance between metal stage 19 and counter electrode 11) and combined electrical capacitance (theoretical electrical capacitance between electrical wiring 7 to which metal stage 19 is connected and counter electrode 11).

In the printed circuit board inspecting apparatus according to the embodiment of the present invention having such a configuration, when inspecting the electric wiring 7 for connecting the front and back of the printed circuit board 5 for disconnection defects,
First, the measuring needle 15 attached to the measuring arm 16 is brought into contact with the terminal 3 belonging to the electric wiring 7, and the metal stage 1
The electric capacitance between the electric wiring 7 to which 9 is connected and the counter electrode 11 is measured by the electric capacitance meter 10.

The value measured by the capacitance meter 10 and the expected value stored in the quality determination condition storage unit 13 (theoretical between the electric wiring 7 connected to the metal stage 19 and the counter electrode 11) (Electric capacity) is compared by the quality determination unit 12, and if the measured value is smaller than the expected value, it is regarded as a disconnection defect and the quality display unit 14 displays the quality result.

When the electric wiring 7 is inspected, the rear surface connector pins 4 belonging to the electric wiring 7 are connected to the metal stage 19, so that the terminals 3 and the rear surface connector pins 4 are normally electrically connected and there is no disconnection defect. The electric capacitance meter 10 includes an electric capacitance C3 between the lower layer wiring 22 and the counter electrode 11 and an upper layer wiring 2
It is possible to measure a combined capacitance of the capacitance C4 between the electrode 3 and the counter electrode 11 and the capacitance C5 between the metal stage 19 and the counter electrode 11. This is equal to the expected value, so
The quality determination unit 12 determines that the electrical wiring 7 is a good product.

On the other hand, when a disconnection portion existing in the electric wiring 7 occurs at a portion very close to the back surface connector pin 4, the electric wiring 7 is not electrically connected to the metal stage 19, so that the electric capacitance meter 10 , The electric capacitance C3 between the lower layer wiring 22 and the counter electrode 11, and the upper layer wiring 23 and the counter electrode 11
A capacitance value that is approximately equal to the combined capacitance with the capacitance C4 between is measured.

At this time, in the conventional example shown in FIG. 2, the electric wiring 7 is erroneously determined as a non-defective product, but in the present embodiment, as described above, the electric wiring 7 and the metal stage are connected via the back surface connector pin 4. 19 is connected to measure the electric capacitance between the electric wiring 7 to which the metal stage 19 is connected and the counter electrode 11, so that the metal stage 19 connects the expected value, which is the criterion for the quality judgment. Since the theoretical electric capacity between the electric wiring 7 and the counter electrode 11 can be set, the measured value when the disconnection point is generated at a position very close to the back surface connector pin 4 is smaller than the expected value. Becomes

Therefore, the measuring needle 15 is attached to the backside connector pin 4.
The quality determination unit 12 makes contact with the
It is also possible to detect a disconnection defect that has occurred in a portion very close to the back surface connector pin 4.

If a metal stage 19 having a sufficiently large area is used, the expected value compared with the electric capacitance value measured by the inspection of the electric wiring 7 in the pass / fail judgment section 12 can be increased. Therefore, it is possible to more reliably detect a disconnection defect that has occurred in a portion very close to the back surface connector pin 4.

Further, in this embodiment, the rear surface connector pin 4 is used.
A metal stage 19 is used as a conductor connected to the backside connector pin 4 which is usually made of metal in consideration of using the stage for inspection. It is intended to connect to. Therefore, the conductor connected to the back surface connector pin 4 is not limited to the metal stage 19, and even when the printed circuit board 5 is supported using the stage, a conductor is prepared separately from this stage. Then, this may be connected to the back surface connector pin 4.

Further, in this embodiment, the back surface connector pin 4 is used.
However, even if there is a plurality of wirings 7, that is, even if there are a plurality of wirings 7 that electrically connect the front and back of the printed circuit board 5, by performing the above operation individually for each wiring 7. Of course, the same effect can be realized. In this case, all the backside connector pins 4
Is connected to the metal stage 19. Further, as described above, when connecting a conductor different from the stage, all the back surface connector pins 4 may be connected to one conductor, or a separate conductor may be connected to each back surface connector pin 4. You may do it.

In this embodiment, the case where the conductor is connected to the back surface connector pin 4 on the wiring 7 that electrically connects the front and back of the printed circuit board 5 has been described, but the conductor is connected to the other wiring (wiring 6). You may connect. That is, the wiring 6
By connecting a conductor to the upper terminal 1, even if a disconnection defect occurs near the terminal 1, it is possible to detect this disconnection defect only by bringing the measuring needle 15 into contact with the terminal 2 for inspection. become. Similarly, by connecting a conductor to the terminal 2 on the wiring 6, even if a disconnection defect occurs in the vicinity of the terminal 2, it is only necessary to bring the measuring needle 15 into contact with the terminal 1 and perform an inspection. It becomes possible to detect.

As described above, by connecting the conductor to one terminal on the wiring provided on the printed circuit board, it is possible to perform the inspection from the other terminal without performing the inspection from the one terminal and disconnect the wire. It is possible to reliably detect defects.

[0045]

The first effect of the present invention is that the pass / fail judgment can be reliably performed without performing measurement from both terminals on the wiring provided on the printed circuit board. The reason is that by connecting a conductor to the terminal on the wiring to be inspected, the electric capacitance between the wiring to which this conductor is connected and the counter electrode is measured, and the measured electric capacitance is This is because the quality of the wiring to be inspected is determined on the basis of this, so that in the past, it is possible to reliably perform the quality determination unless measurement is performed from both terminals on the wiring to be inspected. However, in the present invention, it becomes possible to reliably perform the pass / fail judgment without performing the measurement from the terminal to which the conductor is connected.

The second effect of the present invention is that it is possible to prevent an erroneous determination when the quality of the wiring electrically connecting the front and back of the printed circuit board is determined. The reason is that if the wiring to be inspected is a wiring that goes to the front and back of the printed circuit board, the conductor connected to the terminal on the wiring to be inspected should be connected to the terminal (back side terminal) located on the back side of the printed circuit board. This is because it is possible to reliably perform the pass / fail determination without performing the measurement from the back surface terminal, and it is possible to prevent the erroneous determination due to the inability to perform the measurement from the back surface terminal.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a printed circuit board inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional printed circuit board inspection device.

[Explanation of symbols]

1, 2, 3 terminals 4 Back side connector pin 5 printed circuit boards 6,7 wiring 10 capacitance meter 11 Counter electrode 12 Pass / fail judgment section 13 Pass / fail judgment condition storage section 14 Pass / fail display 15 Measuring needle 16 measuring arm 19 metal stage 20,22 Lower layer wiring 21,23 Upper layer wiring

Claims (12)

[Claims] 1. A printed circuit board inspection method for determining the quality of a wiring provided on a printed circuit board, wherein a counter electrode is arranged facing the printed circuit board, and a conductor is connected to a terminal on the wiring. A method of inspecting a printed circuit board, wherein an electric capacitance between the wiring to which the conductor is connected and the counter electrode is measured, and the quality judgment is performed based on the measured electric capacitance. 2. The print according to claim 1, wherein the wiring is a wiring extending to the front and back of the printed circuit board, and the conductor is connected to a terminal on the wiring located on the back surface of the printed circuit board. Substrate inspection method. 3. A printed circuit board inspection for determining the quality of the wiring by using a measuring needle for electrically connecting to the wiring provided on the printed circuit board and a counter electrode arranged so as to face the printed circuit board. A method, wherein a conductor is connected to a terminal on the wiring, and the measuring needle is brought into contact with the wiring to measure the electric capacity between the wiring and the counter electrode to which the conductor is connected, A method of inspecting a printed circuit board, wherein the quality judgment is performed based on the measured electric capacity. 4. The printed circuit board inspection method according to claim 3, wherein the conductor is connected to one terminal on the wiring, and the measuring needle is in contact with the other terminal on the wiring. 5. The wiring is a wiring extending to the front and back of the printed circuit board, one terminal on the wiring is a terminal located on the back surface of the printed circuit board, and the other terminal on the wiring is the printed circuit board. The printed circuit board inspection method according to claim 4, wherein the terminal is located on the surface of the. 6. The stage according to claim 2, wherein a stage for supporting the printed circuit board is used as the conductor.
The printed circuit board inspection method described. 7. The quality judgment is made by comparing the measured electric capacity with a theoretical electric capacity between the wiring connected to the conductor and the counter electrode. The printed circuit board inspection method according to claim 1. 8. A printed circuit board inspection device for determining the quality of a wiring provided on a printed circuit board, wherein a conductor is connected to a terminal on the wiring, and the counter is arranged to face the printed circuit board. An electrode, a measuring needle, an electric capacity measuring means for measuring an electric capacity between the counter electrode and the wiring to which the conductor is connected by contacting the measuring needle with the wiring, and the electric capacity measurement A printed circuit board inspecting device, comprising: a pass / fail determination means for performing the pass / fail determination based on the electric capacity measured by the means. 9. The printed circuit board inspection device according to claim 8, wherein the conductor is connected to one terminal on the wiring, and the measuring needle is in contact with the other terminal on the wiring. 10. The wiring is wiring extending to the front and back of the printed circuit board, one terminal on the wiring is a terminal located on the back surface of the printed circuit board, and the other terminal on the wiring is the printed circuit board. The printed circuit board inspection device according to claim 9, wherein the printed circuit board inspection device is a terminal located on the surface of the substrate. 11. The printed circuit board inspection apparatus according to claim 10, further comprising a stage for supporting the printed circuit board, wherein the stage is used as the conductor. 12. The quality judgment means compares the measured electric capacity with a theoretical electric capacity between the wiring to which the conductor is connected and the counter electrode to judge the quality. The printed circuit board inspection device according to claim 8, wherein the printed circuit board inspection device is provided.