JP2000275274A - Circuit inspecting method and circuit board corresponding to this inspecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a circuit inspection regardless of the outer shape precision of a circuit board and the position precision of a circuit. SOLUTION: In this inspecting method, magnetic attracting force is applied between a rockably held probe 1 and a circuit 55 to bring the probe 1 into contact with the circuit 55 when bringing the probe 1 into contact with the circuit 55 on a substrate 5 for inspecting the circuit 55. Even if the probe 1 and the circuit 55 are somewhat deviated in position, the probe 1 is rocked into contact with the circuit 55 by the magnetic attracting force, and the probe 1 is made rockable at the tip only.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit inspection method using a contact probe and a circuit board corresponding to the inspection method.

[0002]

2. Description of the Related Art In inspecting a circuit on a substrate, a test is performed by bringing a probe into contact with a predetermined portion of the circuit on the substrate while the substrate is positioned and fixed. FIG. 19 shows an example of an apparatus for this inspection, in which a holding member 21 having a probe 1 connected to a voltage generator is arranged above a positioning table 51 for fixing a substrate 5 by a clamp 50, The probe 1 is brought into contact with a predetermined circuit 55 on the substrate 5 by driving the holding member 21 up and down by a vertical elevating mechanism 20 such as a cylinder. The probe 1 usually has a spring incorporated therein so as to be able to absorb an excessive pushing amount at the time of contact with the predetermined circuit 55.

[0003]

However, in the inspection using the above, when the external dimensions of the substrate 5 are poor or the positional accuracy of the predetermined circuit 55 on the substrate 5 is low, the probe 1 As a result, the circuit cannot be inspected without contacting the circuit 55.

The present invention has been made in view of the above points, and an object of the present invention is to provide a circuit inspection method capable of performing a circuit inspection irrespective of the external accuracy of a circuit board and the positional accuracy of a circuit. And a circuit board corresponding to this inspection method.

[0005]

According to the circuit inspection method of the present invention, when a probe is brought into contact with a circuit on a substrate and the circuit is inspected, the probe and the circuit, which are swingably held, are connected to each other. It is characterized in that the probe is brought into contact with the circuit by using a magnetic attraction force during the operation. Even if the position of the probe and the circuit is slightly displaced, the probe is swung by magnetic attraction acting between the probe and the circuit and contacts the circuit.

[0006] As the probe, a probe having only the tip that can swing freely can be suitably used. In this case,
A probe having a mechanical joint or a joint made of an elastic material at the tip thereof can be used as the probe.

It is preferable to use an electromagnetic driving force of a coil as a driving force for moving the probe toward the substrate, and it is particularly preferable to magnetize the probe with a coil as a source of the electromagnetic driving force.

As the coil in this case, a voice coil motor or an electromagnet which attracts the probe in opposition to the spring-supported probe can be preferably used.

[0009] A means for detecting the inclination of the probe is provided, and the position of the circuit is measured from the output of the detecting means, and the position detecting means for detecting a plurality of positions of the probe is provided. The position shift amount of the circuit may be measured from the output.

As the substrate, a magnetic layer is provided only on the circuit to be inspected, a magnetic layer is provided on the circuit, and a conductive layer having high magnetic absorption is provided on the magnetic layer of the circuit to be inspected. In addition, a circuit in which a circuit to be inspected is provided at a higher position than a circuit to be inspected can be suitably used.

In the circuit board according to the present invention, a circuit to be inspected is provided with a magnetic layer, or the circuit is provided with a magnetic layer and has a high magnetic absorption on the magnetic layer of the circuit to be inspected. It is characterized in that a conductor layer is provided, or a magnetic layer is provided on a circuit to be inspected, and a circuit to be inspected is provided at a higher position than a circuit not to be inspected. Magnetic attraction can be exerted between the probe and the probe.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an example of an embodiment. In FIG. 1, reference numeral 1 denotes a probe 1 connected to a voltage generator, which has a rod shape and is made of iron, nickel, cobalt or the like. The probe 1 formed of the conductive magnetic material of the first embodiment is provided with an insertion hole 22 formed in the holding member 21.
Is inserted into the holding member 21 with play so that the holding member 21 can swing freely.
And a coil 30 is disposed on the outer periphery.

The contact of the probe 1 with the circuit 55 on the substrate 5 is performed by lowering the holding member 21 by an up-and-down elevating mechanism 20 such as a cylinder. 1 itself is magnetized.

On the other hand, the circuit 55 of the substrate 5 is formed by providing a conductive magnetic layer 57 made of nickel on a conductive layer 56 made of copper, and further having a conductive layer 58 made of gold thereon. ing.

For this reason, if the tip of the probe 1 is brought close to the substrate 5 in a state where the probe 1 is magnetized by energizing the coil 30, the coercive force acts between the probe 1 and the magnetic layer 57. Since the probe 1 is swingably held by the holding member 21, even when the probe 1 is not located immediately above the circuit 55, the tip of the probe 1 contacts the circuit 55 and the circuit 55 can be inspected. State. Therefore, even when the external dimension accuracy of the substrate 5 is poor or the positional accuracy of the circuit 55 on the substrate 5 is poor, circuit inspection can be performed. It is needless to say that an electromagnetic force sufficient to tilt the probe 1 toward the magnetic layer 57 against the bias by the spring 23 is generated.

Instead of making the entire probe 1 swingable, only the tip of the probe 1 may swing freely as shown in FIG. in this case,
As shown in FIG. 3A, a mechanical joint 11a such as a ball joint or a universal joint, or a joint 11b made of a flexible material such as a spring or a wire may be provided at the tip of the probe 1. These joints 11 are also made of a magnetic material, and the weight of the tip is made larger than the coercive force at the joint so that the tip of the probe 1 is not magnetized toward the root.

Since the entire probe 1 does not need to be swung with respect to the holding member 21, the reliability and durability of the probe 1 are improved, and the weight of the swing part is reduced. Responsiveness during magnetism is increased.

When the circuits 55 on the substrate 5 are densely formed and the circuit 55 to be inspected is close to the circuit 55 'not to be inspected, as shown in FIG. 57 may be provided only in the circuit 55 to be inspected, or as shown in FIG. 5, the magnetic absorption may be higher on the magnetic layer 57 of the circuit 55 to be inspected than on the magnetic material (Ni) of the magnetic layer 57. By fixing a conductive object (eg, Au) 59 having a high level, the probe 1 is a circuit 55 to be inspected.
Make sure that only side contacts.

As shown in FIG. 6, the circuit 5 to be inspected is
5 may be arranged one step higher than the circuit 55 'not to be inspected.

Fixing the highly magnetically absorbing object 59 to the circuit 55 to be inspected is performed by dispensing the conductive adhesive 60 onto the circuit 55 to be inspected by a dispense coating method (see FIG. 6A) or by transferring. It is applied by a coating method (see FIG. 6 (b)) or a screen printing method (see FIG. 6 (c)).
The mounting may be performed using the pickup nozzle 65 of the mounting machine as shown in FIG.

To provide the magnetic layer 57 only on the circuit 55 to be inspected, as shown in FIG. 8, a conductive film 501 as a circuit underlayer is formed on the surface of the substrate 5 by vacuum evaporation, sputtering or electroless plating. Later, laser light 5
In step 02, a circuit contour and a power supply circuit for electrolytic plating are formed by a circuit patterning method, and a conductive layer 56 made of copper is formed by electrolytic plating / soft etching. Then
As shown in FIG. 8D, a Ni plating circuit (magnetic layer 57) is formed only on a specific circuit 55 by an exposure and development method using a mask pattern.
As shown in FIG. 8E, the conductive layer 58 can be formed by performing Au plating by electrolytic plating.

To arrange the circuit 55 to be inspected one step higher than the circuit 55 'not to be inspected, as shown in FIG. 9, a substrate 5 having a projection or a step is formed by injection molding, and A conductive film 50 serving as a circuit base on the substrate 5
1 is formed, a circuit pattern is drawn by patterning with a laser beam 502, then the conductive layer 56 is formed by electrolytic copper plating and soft etching, and the magnetic layer 57 is formed by Ni plating.
The conductive layer 58 may be formed by performing Au plating.

FIG. 10 shows an example of another embodiment. In this embodiment, a coil 30 for magnetizing the probe 1 also serves as an up-and-down mechanism 20 for moving the probe 1 up and down. Specifically, the voice coil motor 3 is used by using the voice coil motor 3. When the coil 30 is energized,
The probe 1 is driven downward and the probe 1 is magnetized. In the figure, reference numeral 26 denotes a coupling connecting the movable portion of the voice coil motor 3 and the holding member 21 holding the probe 1, 33 denotes a permanent magnet, 34 denotes a linear guide, and 35 denotes a stopper.

Assuming that the mass of the entire movable section is M and the electromagnetic force of the voice coil motor 3 is F, the current command value from the current driver 36 is set to satisfy Mg> F, and as shown in FIG. Is lifted from the initial position A held by the stopper 35 to the standby position B, and the setting of the substrate 4 is performed in this state. Next, the movable portion is lowered by flowing a current of the opposite polarity through the coil 30. When the probe 1 approaches the circuit 55 of the substrate 5, the probe 1 magnetized by the magnetic field generated in the voice coil motor 3 becomes a magnetic layer 57.
As shown in FIG. 12, a portion of the distal end side of the joint 11 is attracted to and comes into contact with the circuit 55 by the electromagnetic attraction force acting between the two.

FIGS. 13 to 15 show other examples. The coil 30 for magnetizing the probe 1 suspended and supported by the tension spring 24 also serves as a power for lowering the probe 1. The coil 30 is provided with a circular plate 25 made of a magnetic material and provided on the holding member 21. A plurality (three in the illustrated example) of electromagnets including the coil 30 and the iron core 37 are arranged below, and these electromagnets are arranged around the probe 1 at equal intervals.

In the initial state, the movable portion is elastically supported by the tension spring 24 to position the tip of the probe 3 at the initial position A. At this time, the mass of the movable part is M,
Assuming that the spring constant is k and the amount of extension of the extension spring 24 from its natural length is Δx1, Mg = k · Δx1 is in a balanced state. In the drawing, S indicates the probe tip position at the spring natural length.

Assuming that the electromagnetic force of the electromagnet is F, the probe 1 is set by setting the current command value from the current driver 36 to be Mg + F = kｘΔx2 (Δx2: extension from the natural length of the spring). Balance at position B.

Also in this case, the probe 1 can be lowered by energizing the coil 30, and an electromagnetic attractive force can be exerted between the probe 1 and the magnetic layer 57 of the circuit 55 of the substrate 5. In the illustrated example, the probe 1 is swingable with six degrees of freedom by the hanging support by the tension spring 24 and the three electromagnets. It is possible to cope with deviations of the target circuit 55 in all directions.

In this case, as shown in FIG. 16, if a position sensor 7 such as an eddy current type position sensor is arranged to face the plate 25 so that the position of the plate 25 can be measured, the circuit 55 can be measured from the inclination of the probe 1. Can be measured. That is, FIG.
As shown in FIG.
If the length from the probe to the tip of the probe 1 is L, the distance from the position sensor 7 at one end of the plate 25 is d1, and the distance from the position sensor 7 at the other end of the plate 25 is d2, the displacement amount D is D = L (d1-d2) / 2a.

After setting the current command value so that the tip of the probe 1 is balanced at the position B, the electromagnetic force F
18 (a), the current command value from the current driver 36 is controlled so that the difference between the force and the force Fs by the tension spring changes as shown in FIG. If a rapid change is seen as shown in ()), it can be determined that the probe 1 and the circuit 55 have contacted at that time. When the probe 1 does not contact the substrate 5, the output of the position sensor 7 gradually changes as shown in FIG.

[0031]

As described above, in the circuit inspection method according to the present invention, when the probe is brought into contact with the circuit on the substrate and the circuit is inspected, the probe is held between the swingable probe and the circuit. The probe is brought into contact with the circuit by applying magnetic attraction force to the circuit, so even if the position of the probe and the circuit is slightly shifted, the probe is swung by the magnetic attraction force acting between the probe and the circuit. The circuit inspection can be performed regardless of the external accuracy of the circuit board and the positional accuracy of the circuit.

When a probe whose tip is free to swing is used as the probe, the mass of the portion that is swung by the magnetic attractive force can be reduced, so that an inspection with good response can be performed. In this case, a probe having a mechanical joint or a joint made of an elastic material at its distal end can be suitably used.

It is preferable to use an electromagnetic driving force by a coil as a driving force for moving the probe toward the substrate. Since the driving of the probe can be performed at a high speed, the inspection tact can be improved. Especially when magnetizing the probe with a coil as a source of electromagnetic driving force,
The number of parts can be reduced, and the mechanism can be simplified, so that the cost can be reduced.

When a voice coil motor is used as the coil in this case, the weight can be reduced and the strength of the entire device can be reduced, so that the cost can be reduced. In addition, when an electromagnet that attracts the probe in opposition to the spring-supported probe is used, the cost of parts can be reduced, and the probe can be swingably supported without difficulty.

There is provided means for detecting the inclination of the probe, and the position of the circuit is measured from the output of the detecting means. If the amount of circuit displacement is measured from the output, data for production control of the substrate can be obtained simultaneously.

As the substrate, a magnetic layer is provided only on the circuit to be inspected, a magnetic layer is provided on the circuit, and a conductive layer having high magnetic absorption is provided on the magnetic layer of the circuit to be inspected. By using a circuit that is to be inspected at a higher position than a circuit that is not to be inspected,
The followability and contact reliability of the probe to the circuit to be inspected can be improved, and in particular, when the magnetic layer is provided only in the circuit to be inspected, an increase in the production cost of the substrate can be suppressed.

A circuit board in which a magnetic layer is provided on a circuit to be inspected, or a circuit in which a magnetic layer is provided in a circuit and a conductor layer having high magnetic absorption is provided on the magnetic layer of the circuit to be inspected The substrate can increase the magnetizability of only a specific circuit, and can be differentiated from a normal circuit in terms of magnetic properties. In addition, a circuit board provided with a magnetic layer on a circuit to be inspected and a circuit to be inspected provided at a higher position than a circuit not to be inspected can eliminate a possibility that a circuit outside the inspected object comes into contact with a probe. it can.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an example of an embodiment of the present invention.

FIG. 2 is a schematic view of another example of the above.

FIGS. 3 (a) and 3 (b) are partial front views showing examples of joints used in the above.

FIG. 4 is a schematic diagram when another circuit board is used.

FIG. 5 is a schematic diagram when another circuit board is used.

FIG. 6 is a schematic diagram when another circuit board is used.

FIGS. 7A to 7C are explanatory diagrams illustrating an example of a process of applying an adhesive to a circuit board, and FIG. 7D is an explanatory diagram illustrating an example of manufacturing a circuit board.

FIG. 8 is an explanatory view showing a procedure for manufacturing a circuit board.

FIG. 9 is an explanatory view showing another manufacturing procedure of the circuit board.

FIG. 10 is a sectional view showing an example of a specific embodiment.

FIG. 11 is a cross-sectional view showing a state where the probe is floated.

FIG. 12 is a partial front view showing a state where the probe tip is in contact with a circuit.

FIG. 13 is a sectional view showing another example of the specific embodiment.

FIG. 14 is a horizontal sectional view of the same.

FIG. 15 is a sectional view showing a state where the probe is lowered.

FIG. 16 is a sectional view of still another example of the above.

FIG. 17 (a) is a front view of the same probe, and FIG. 17 (b) is an explanatory diagram of a tilt and a shift amount.

FIG. 18 (a) is a time chart showing changes in electromagnetic force,
(b) is a time chart showing a change in the position sensor output during contact, and (c) is a time chart showing a change in the position sensor output during non-contact.

FIG. 19 is a schematic view of a conventional example.

[Explanation of symbols]

 1 Probe 5 Board 30 Coil 55 Circuit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kenichi Kimura 1048, Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. Terms (reference) 2G011 AA09 AB08 AC01 AC06 AC14 AE11 AF01 AF07 2G014 AA01 AA32 AB59 AC10 AC12 2G032 AB01 AE01 AF03 AF04 AF05 AK03 AK11 AL03

Claims (15)

[Claims] In testing a circuit by bringing the probe into contact with a circuit on a substrate, the probe is brought into contact with the circuit by applying a magnetic attraction force between the probe and the circuit, which are swingably held. A method for inspecting a circuit, comprising: 2. The circuit inspection method according to claim 1, wherein a probe whose tip is free to swing is used as the probe. 3. The circuit inspection method according to claim 2, wherein a probe having a mechanical joint or a joint made of an elastic material at its tip is used as the probe. 4. The circuit inspection method according to claim 1, wherein an electromagnetic driving force by a coil is used as a driving force for moving the probe toward the substrate. 5. The circuit inspection method according to claim 4, wherein the probe is magnetized by a coil as a source of electromagnetic driving force. 6. The circuit inspection method according to claim 4, wherein a voice coil motor is used as the coil. 7. The circuit inspection method according to claim 4, wherein an electromagnet that attracts the probe is used as a coil in opposition to the spring-supported probe. 8. The circuit inspection according to claim 1, further comprising a detecting means for detecting the inclination of the probe, and measuring a displacement amount of the circuit from an output of the detecting means. Method. 9. The apparatus according to claim 1, further comprising a position detecting means for detecting a plurality of positions of the probe, and measuring a displacement amount of the circuit from an output of the position detecting means. The circuit inspection method according to the paragraph. 10. The circuit inspection method according to claim 1, wherein a substrate provided with a magnetic layer only on a circuit to be inspected is used as a substrate. 11. The circuit as claimed in claim 1, wherein a magnetic layer is provided on the circuit as a substrate and a conductor layer having high magnetic absorption is provided on the magnetic layer of the circuit to be inspected. A circuit inspection method according to any one of the above items. 12. The circuit inspection method according to claim 1, wherein a circuit to be inspected is provided at a higher position than a circuit not to be inspected as a substrate. . 13. A circuit board, wherein a circuit to be inspected is provided with a magnetic layer. 14. A circuit board comprising a circuit having a magnetic layer and a conductor layer having a high magnetic absorption on the magnetic layer of the circuit to be inspected. 15. A circuit board comprising: a circuit to be inspected; a magnetic layer provided on the circuit to be inspected; and a circuit to be inspected provided at a higher position than a circuit not to be inspected.