JPH02190773A - Method for inspecting printed wiring board - Google Patents

Abstract

PURPOSE:To easily inspect a high-density pad by bringing a probe into contact with a through hole (TH), detecting a short circuit between circuits, short- circuiting between pads by conductive rubber and detecting the breaking of wire between the pads the THs. CONSTITUTION:The printed wiring board 1 after solder resist processing 13 which has only a simple pattern wherein the THs 8 and pads 4 are connected in 1:1 proportion is installed at a specific position and the probes 5 are pressed down simultaneously to brought into contact with the TH 5; and the conduction state between of each probe 5 is checked to detect whether or not a circuit on the board 1 short-circuits. While the each probe 5 is brought into contact with the TH 8, the conductive rubber is pressed against the pad 4 to short- circuit the pad 4 with each other and the conduction states of between the respective probes 5 are checked to inspect the breaking of wire of the circuit of the board 1. Consequently, even a board which is extremely narrow in pad interval can be inspected and pads are not damaged. Further, an inexpensive elastic conductor is usable to eliminate the need for a jig circuit board for inspection, thereby performing the inspection at a low cost in a short time.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a printed wiring board inspection method I, and relates to a wiring inspection method (this method) for electrically inspecting the four-fold state of a printed wiring board. related.

[Conventional technology]

Conventionally, as a wiring inspection method for this type of printed wiring board, as shown in FIG.
A method was used in which the probes 5 are brought into contact with the pads 4 which are partially soldered by the solder resist 13, and the continuity between the probes 5 is electrically tested.

Further, as a conventional glaze technique using anisotropic conductive rubber, there is, for example, the second method described in Japanese Patent Publication No. 59-206776.

This second method will be explained below using FIG. 5.

First, a printed wiring board 1 to be inspected for fabric dryness and a pair of test jig circuit boards 9 are placed so that their front and back main surfaces face each other, and the anisotropic conductive rubber 10 is placed between them. .

Here, the test jig circuit board 9 is provided with a test pad 11 at a position opposite to the pad 4 and through hole 8 of the printed wiring board 1, and this test pad 11 is located at the board end 1c.
It is connected to a certain probe through hole 12. solder resist) 13 is an inspection jig plate 9 and a printed wiring board l
This is for maintaining insulation between the circuit #l18.

Further, the anisotropic conductive rubber 10 is pressed from both sides, so that it exhibits conductivity only in the thickness direction and is not conductive in the planar direction.

Therefore, by pressing these together, the pads 4 and through-holes 8 of the printed wiring board 1 and the probe through-holes 5 at the ends of the test jig circuit board 9 are separated from each other by the anisotropic conductive rubber 10. electrically connected via.

Next, by bringing the probe 5 into contact with the probe through hole 121 and applying a voltage, a current flows through the circuit on the printed wiring board 1. Therefore, by checking whether there is continuity between the probes 5, wiring inspection can be performed.

[Problems to be Solved by the Invention] However, the conventional printed wiring board wiring inspection method described above had the following drawbacks.

That is, in the first conventional method described above, there is a limit of 8 degrees in the diameter of the probe 5 and the machining of the jig plate 6 that holds the probe 5. ．．
It was extremely difficult to inspect high-density wiring of 27n or less.

Therefore, a method using anisotropic conductive rubber as in the second method has been proposed, but originally, anisotropic conductive rubber allows a slight current to flow in the plane direction.
1 and the pads 40 becomes narrower, the 'FIt current flowing between the pads also increases, so that the pitch of the pads becomes 0.
It was difficult to inspect high-density wiring of 6351111 or less.

Furthermore, since the inspection jig circuit board 9 must be manufactured, this requires a lot of man-hours, making it impossible to prepare for inspection in a short period of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board inspection method that overcomes the above-mentioned drawbacks and allows easy wiring inspection of high-density pads.

[Means to solve the problem]

The configuration of the printed wiring board inspection method of the present invention is such that a 10-wire is brought into contact with the through hole of the printed wiring board in which the component connection pad is connected to the through hole by wiring to electrically check the short circuit between each circuit. a process of detecting the difference between the two pads, and pressing a rubber band 4 on a desired part of the pad to electrically connect the pads to each other.
The method is characterized by comprising a step of electrically detecting a break in the wiring between the pad and the through hole by bringing the probe into contact with the through hole after shorting the pad.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

@1 Figure G) is a perspective view showing a printed wiring board inspection method according to an embodiment of the present invention;
FIG.

In FIG. 1(ω), the printed wiring board 1 is the object of inspection in this embodiment, for example, the second IgIζ
This is a printed wiring board treated with a solder resist 13 having only a simple pattern in which through holes 8 and pads 4 are connected in an l-to-l ratio as shown.

Further, the conductive rubber 2 is bonded to a metal plate (for example, an aluminum plate) 3 with a 4tIL adhesive (for example, silver paste, etc.), and by pressing these together against the pad 4 with pressure, the pad 4 can be fixed. They can be shorted together.

Next, the probes 5 are held at the positions of the through holes 8 to be contacted by the guide holes 7 provided in the jig plate 6, and during inspection, the probes 5 are pressed down by applying downward pressure. Make contact with through hole 8 to establish continuity!
It's happening.

As for the inspection procedure, first, the printed wiring board 1 is placed on a predetermined position, and then the probes 5 are pushed down all at once to bring them into contact with the through holes 8. In this state, the presence or absence of a short circuit in the circuit of the printed wiring board 1 is detected by checking the conduction state between each of the 10 pins.

The above method is possible because the printed wiring board 1 to be inspected has one through hole 8 and one pad 4, respectively, as described above.
This is because there is essentially no conduction between the respective circuits since it has only patterns that are connected in pairs.

Next, while keeping the probe 5 in contact with the through hole 8I, press the conductive rubber 2 against the pad 4,
The pads 4 are short-circuited. In this state, by checking the continuity between the probes 5, the circuit of the printed wiring board 1 is inspected for disconnection.

In this way, it was possible to inspect the printed wiring board 1 for short circuits and disconnections.

FIG. 5 is a sectional view showing a printed wiring board inspection method according to another embodiment of the present invention.

In FIG. 5, in this embodiment, a printed wiring board 1 is the same as in the previous embodiment, and is prepared as a printed wiring board having pads for mounting components.

Next, the conductive rubber 2a, 2b is a metal aphrodisiac plate 2a.

2b (for example, an aluminum plate) I is bonded with a conductive adhesive (for example, silver paste), and by pressing these together with pads 4a and 4bi under pressure,
The pads 4a and 4b are arranged so that they can be short-circuited to each other.

Next, the probes 5a, 5b, 5c are held below the positions of the through holes 8a, 8b, 8c to be contacted by the guide holes 7a + 7b + 7c provided in the jig plate 61, and are pushed upward. As a result, the through holes f3a, 8b, and 8c are brought into contact with each other so as to be electrically conductive.

The inspection procedure involves placing a trenchless printed wiring board in a predetermined position.
After installing this, push up the probes 5a, 5b, and 5c all at once to open the through hole 8a*8b*8c
bring into contact with. In this state, each probe 5a.

5b and 5c - This is to check for short circuits and breaks in the circuits connecting through holes such as through holes 8b and 8c.

Next, with the front 8-pin probes 5a, 5b, 5c in contact with the through holes 8a, 8b, 8c, the conductive rubbers 2a, 2b are pressed against the pads 4a, 4b, and the pads 4a+4 b are shorted together. In this state, by checking the conduction state between each probe 4, the circuit connecting the pad and through hole, and the pad 4a
Check for disconnection in the circuit that connects the bands, such as the circuit that connects between the pad 4b and the pad 4b. In this way, short circuits and disconnections in the circuits of the printed wiring board 10 could be inspected.

In any of the examples, conductive rubber 2.22°2b
Unlike the conventional example, the anisotropic 4-conductor rubber is not required, and a conductor with high strength can be used.

In each of the above-mentioned embodiments, a short circuit between each circuit is electrically detected by touching one through hole of a printing distribution board with a probe, and then a desired part of one pad is detected. The method includes a step of pressing a conductive rubber to short-circuit the pads, and then bringing a probe into contact with the through-hole to electrically detect a break in the circuit between the pad and the through-hole.

[Effects of the Invention] As explained above, i″L according to the present invention has the following effects.

(1) Inspection is possible even if the spacing between the pads arranged on the printing board is extremely narrow.

I) The pads on the printed wiring board are made using a rubber contact method, so the pads will not be damaged.

Moreover, it is possible to use an inexpensive and elastic conductor instead of a special material such as anisotropic conductive rubber.

(m) Minute holes in the inspection jig plate do not require processing or an inspection jig circuit board, so short-term inspections can be performed at low cost.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view showing a method of inspecting a printed distribution board according to an embodiment of the present invention, and FIG.
2 is a plan view showing a part of the printed wiring board of FIG. 1, FIG. 3 is a sectional view showing another embodiment of the present invention, and FIGS. 4 and 5 are 1 is a cross-sectional view showing a conventional printed wiring board inspection method. 1...Printed wiring board, 2.2a, 2b...
・Conductive rubber, 3, 3 a, 3 b-Gold plate, 4
．． 4 a +4b...Pad, 5.5a, 5b
, 5c...Probe, 6...Jig plate, 7
．． 7a, 7b, 7c...Guide hole, 8.8
a, 8b, 8c...Through hole, 9...
・Inspection jig plate, 10...Anisotropic conductive rubber, 1...Inspection pad, 12...Through hole for probe, 13... solder resist.

Claims (1)

[Claims] In an inspection method for a printed wiring board in which component connection pads on the main surface are electrically connected by through holes and wiring,
a step of electrically detecting a short circuit between each wiring by bringing a probe into contact with the through hole; and a step of pressing a conductive rubber onto a desired portion of the pad to electrically short circuit the pads; A method for calibrating a printed wiring board, comprising the step of bringing the probe into contact with the through hole to electrically detect a break in the wiring between the pad and the through hole.