JP2003294802A - Method and device for inspecting printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method and an inspection device which promote insulation degradation between two conductor patterns of a printed wiring board for detecting a potential short circuit. <P>SOLUTION: A high voltage pulse is applied between the two conductor patterns for a prescribed time period, thus promoting insulation degradation. Then a DC voltage is applied for continuity inspection, to detect a potential short circuit. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board inspection method and inspection apparatus.

[0002]

2. Description of the Related Art Conventionally, as a continuity inspection of a printed wiring board, inspection pads are provided at both ends of the printed wiring board, an inspection probe is brought into contact with these pads, an electric current is passed while sequentially switching the portions to be inspected, disconnection or Short circuit
Was inspecting.

[0003]

However, in the above-mentioned method, defects can be found in those that are completely disconnected or short-circuited in the inspection stage.
As shown in FIGS. 7 and 8, when a whisker-shaped conductor 23a is close to an adjacent conductor 22, or a protrusion 23b is formed on the conductor.
, Or the conductor 22 as shown in FIG.
If it is about to be disconnected, it will be difficult to find and remove it, and there is a possibility of disconnection or short circuit while using the electronic device.

In particular, when an electronic circuit in an electronic device is in an operating and energized state, a short circuit may occur between two independent circuits due to insulation deterioration called migration.

The migration is a phenomenon in which an ionized metal migrates from one of the counter electrodes on an insulating substrate to form a precipitate called dendrite.

The main cause of migration is due to an electrochemical reaction. When a direct current voltage is applied between electrodes via an electrolyte, the electrode metal in the high parallel electrode potential region shown in the electrochemical example is ionized. And is eluted.

In addition, it is said that the following factors are related to the cause of migration and progress. (1) Application of DC voltage (2) Kind of conductor metal: silver, lead, copper, tin, etc. (3) Insulating layer: Difference in material, structure, and structure. (4) Process: Foreign matter mixing, ionic residue, crack generation, cleaning degree, etc. (5) Environment: Temperature, humidity, ionic components, etc., and in fact, dendrites are generated in the form of a combination of these factors, which causes insulation deterioration.

In particular, if the wiring of a printed wiring board has a high density and is made finer, the rate of formation of precipitates increases, insulation breakdown between the wirings proceeds, and insulation deterioration easily occurs.

Therefore, during the electrical inspection of the printed wiring board, a short circuit is about to occur, that is, a potential short circuit is found.
Removing it becomes important.

The present invention is intended to solve the above problems, and provides a method and apparatus for inspecting a printed wiring board, which is effective for detecting a potential short circuit between two conductor patterns and removing it. It is provided.

[0011]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is, in particular, a pulse voltage having a predetermined pulse width between at least two conductor patterns of a printed wiring board. Is a method of inspecting a printed wiring board, which comprises a step of applying a plurality of times and a step of applying a DC voltage between the conductor patterns, which promotes insulation deterioration between the circuits, and then a DC voltage between the conductor patterns. By applying a voltage, the insulation resistance value or the presence or absence of conduction can be confirmed, and a potential short circuit can be detected.

The invention according to claim 2 of the present invention is
The method for inspecting a printed wiring board according to claim 1, wherein a direct current voltage is alternately applied to the two conductor patterns as the pulse voltage, and insulation deterioration is promoted from both of the two conductor patterns. The potential short circuit can be efficiently detected.

The invention according to claim 3 of the present invention is
The pulse voltage is the method for inspecting a printed wiring board according to claim 1, characterized in that an alternating voltage is applied to two conductor patterns, which may be generated by brush-polishing a conductor circuit. This is particularly effective when detecting a short circuit (commonly called whisker short).

The invention according to claim 4 of the present invention is
The pulse voltage is 150 to 500 V, which is the method for inspecting a printed wiring board according to claim 1, which causes dielectric breakdown due to high voltage and burnout of a land pattern due to heat of contact resistance. In other words, it shows the setting range of the pulse voltage for efficiently detecting the potential short circuit.

The invention according to claim 5 of the present invention is
The predetermined pulse width is 0.3 ms to 0.9 ms, which is the method for inspecting a printed wiring board according to claim 1, which promotes insulation deterioration due to occurrence of migration and efficiently It shows a setting range of a pulse width capable of detecting a potential short circuit.

The invention according to claim 6 of the present invention is
In the step of confirming the presence or absence of continuity, the insulation resistance value is used as a judgment standard, and the insulation resistance value is 1.0 × 10 ⁷ Ω.
The method for inspecting a printed wiring board according to claim 1, wherein the insulation resistance value is 1.0 × 10 ⁷ Ω, which is considered to have a high possibility of causing an electronic device to malfunction.
The following is to ensure that the circuit of the potential short circuit that has dropped is removed.

The invention according to claim 7 of the present invention is
The spacing between the conductor patterns is at least 0.04 mm, and it is particularly effective for a method for inspecting a printed wiring board having a potential short circuit in which 20% or more of the spacing between the conductor patterns is a protruding conductor. That is.

The invention according to claim 8 of the present invention is
The pulse voltage is 250 V and the predetermined pulse width is 0.5
The method for inspecting a printed wiring board according to claim 7, wherein the pulse voltage is applied 5 times or more, and the printed wiring board having a latent short circuit according to claim 7. At a pulse width of 0.5 ms at 25
A potential short circuit can be detected by applying a pulse voltage of 0 V five times or more.

The invention according to claim 9 of the present invention is
The printed wiring board inspection method according to claim 1, wherein at least one of the two conductor patterns is a connection land, which is particularly effective between circuits in which a potential short circuit is likely to occur. It is an inspection method.

According to a tenth aspect of the present invention, in particular, a conduction hole is provided immediately below the connection land, and the conduction hole is formed by filling a through hole with a conductive paste and curing it. According to another aspect of the present invention, there is provided a method for inspecting a printed wiring board according to claim 9, which is a particularly effective inspection method between circuits of the printed wiring board which are likely to cause a potential short circuit due to generation of migration.

The invention according to claim 11 of the present invention is characterized in that the through-holes are formed by laser processing after attaching PET films to both surfaces of a sheet-shaped resin-impregnated base material. The method for inspecting a printed wiring board as described in 1) is a particularly effective inspection method between the circuits of the printed wiring board, in which the bleeding of the conductive paste occurs due to the characteristics of the manufacturing process and a potential short circuit easily occurs. .

According to a twelfth aspect of the present invention, in particular, the conductive paste contains silver powder or copper powder, and the method for inspecting a printed wiring board according to the tenth aspect is characterized. This is a particularly effective inspection method between the circuits of the printed wiring board in which migration is more likely to occur due to the inclusion of silver powder or copper powder and a potential short circuit is likely to occur.

According to a thirteenth aspect of the present invention, in particular, at least two terminals out of a plurality of inspection terminals provided at the same position as an inspection pattern on a printed wiring board are set as one set, and two terminals are provided. Printed wiring provided with means for generating a pulse voltage between terminals, means for stopping the pulse voltage, means for applying a constant voltage between the two terminals, and means for detecting a resistance value between the two terminals. It is a board inspection device that accelerates insulation deterioration between circuits and then checks the insulation resistance value or conduction by applying a DC voltage between the conductor patterns to detect a potential short circuit. The inspection device that can be used is provided.

According to a fourteenth aspect of the present invention, in particular, the pulse voltage generating means for generating the pulse voltage between the two terminals alternately generates the pulse voltage between the two terminals. The inspection device for a printed wiring board described above provides an inspection device capable of promoting insulation deterioration from both of the two conductor patterns and efficiently detecting a potential short circuit.

According to a fifteenth aspect of the present invention, in particular, the means for detecting the resistance value between the two terminals is replaced with a means for detecting the current value between the two terminals. The printed wiring board inspecting apparatus according to the item 13 is capable of selecting a resistance value detection or a leakage current detection depending on the form of the inspection object.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an electric circuit for inspecting a printed wiring board, and FIG. 2 is a relationship diagram of voltage and time in the inspection.

First, the principle of the printed wiring board inspection apparatus of the present invention will be described.

In FIG. 1, first, the switch 5d is closed to connect it to the ground of the power source 6b, the switch 5a is closed, and a voltage of 200 V is applied to the circuit. By doing so, the voltage of the lands 4a and 4b is 200V,
The voltage of c and 4d becomes 0V.

Next, all the switches 5a to 5d are replaced, the switch 5c is closed and connected to the ground of the power source 6a, and the switch 5b is closed to apply a voltage of 200V to this circuit. By doing so, the voltage of the lands 4c and 4d becomes 200V, and the voltage of the lands 4a and 4b becomes 0V.

By repeating this several times, a voltage having a pulse waveform as shown in FIG. 2A is applied between the lands 4a and 4b and a voltage having a pulse waveform as shown in FIG. 2B is applied between the lands 4c and 4d. .

By applying the voltage of this pulse waveform, ion migration proceeds between the lands 4a and 4c, and insulation deterioration is promoted.

Thereafter, the switch 5d is closed (connected to the power supply 6b, the switch 5b is opened), and the switch 5a is closed (200 V).
, And switch 5c is opened), and a DC voltage of 200 V is applied between lands 4a and 4c for a predetermined time, and land 4a
The degree of insulation deterioration between the lands 4a and 4c is determined by means of detecting the resistance value between the lands 4a and 4c or means for detecting the current.

When the current value is a certain value or more, or the resistance value is less than the certain value, a short circuit is about to occur, that is, a potential short circuit can be removed.

The switches 5a to 5d and their opening / closing and operation timings can be replaced with a microcomputer or IC.

Whether the resistance value between the lands 4a and 4c is a detecting means or a current detecting means can be adopted depending on the form of the object to be inspected.

Next, the printed wiring board to be inspected will be described.

FIG. 3 shows a multilayer printed wiring board to be inspected. 11 is a copper foil, 12 is a land, 13 is an insulating substrate,
Reference numeral 14 is a conduction hole.

The manufacturing process of this printed wiring board is shown in FIG.
This will be described below with reference to (a) to FIG. (A) A PET film 16 is attached to a prepreg 15 in which an aramid nonwoven fabric is impregnated with an epoxy resin, and via processing is performed using laser light (corresponding to FIG. 4A, the same applies hereinafter). (B) The processed via is filled with a conductive paste 17 made of copper powder and epoxy resin, and the PET film 16 is peeled off. (C) Copper foils 11 are arranged on both surfaces of the prepreg 15 and heated and pressed by a hot press to be laminated. (D) The copper foils 11 on both sides are subjected to conventional etching patterning, and a conductive paste 17 for interlayer conduction is provided inside.
A double-sided printed wiring board having vias filled and cured is obtained. (E) A copper foil 1 is provided with a prepreg filled with the conductive paste 17 on both sides of the double-sided printed wiring board of (d).
The positions of 1 are aligned and arranged, and heated and pressed again by a hot press to form a multilayer. (F) The outermost copper foil 11 of the multilayer printed wiring board of (e) is etched and patterned.

In the above steps, when the PET film 16 of (b) is peeled off, the conductive paste 17 filled in the via may be taken off together, and the copper foil 11
After stacking, the conductive paste 17 may ooze out.

Further, since the distance between the lands 12 is small and the densities are high, the migration of copper in the conductive paste 17 is likely to occur in a continuously energized state for a long time, so that the two circuits are short-circuited. In some cases.

Further, the multilayer printed wiring board as described above has a high wiring accommodating ability and can be formed with a narrow pitch and a thin wire. Incidentally, the land interval, the pattern interval, and the land pattern interval are 0.07 ± 0.03 mm, and the via pitch interval is 0.43 ± 0.06 mm.

In such a narrow-pitch structure printed wiring board, a short circuit between circuits (potential short circuit) occurs.
If the circuit is continuously energized for a certain time or longer, there is a case where a short circuit occurs between the circuits due to insulation deterioration.

Generally, the insulation resistance value between two independent circuits is 1.
Judge with 0 × 10 ⁸ Ω.

In particular, if the insulation resistance value is reduced to 1.0 × 10 ⁷ Ω or less, the electronic device is likely to malfunction.

Next, the insulation resistance value between the independent circuits on the printed wiring board line is 1.0 × 1 under predetermined conditions.
The form of the potential short circuit down to 0 ⁷ Ω or less will be described.

The present inventor has made the following failure modes (A),
It was confirmed that (B) corresponds to that.

The failure mode will be described below.

Defect mode (A): As a design value, the line spacing is 0.
Minimum circuit distance of 0.04m against 07 ± 0.03mm
When 20 m or more of the circuit interval has a protruding conductor between the circuits when finished to m.

Defect mode (B): 0.01 mm when the minimum land interval is 0.04 mm with respect to the designed land interval of 0.07 ± 0.03 mm
When the paste of the above size (length) is bleeding.

These are grasped by the present inventor based on confirmation experiments and analysis of defective products.

That is, at 80 ° C./85% humidity, 100 V
In the case of the failure mode (A) and the failure mode (B), insulation deterioration occurs with a probability of 90% or more after 500 hours (1.0 ×).
10 ⁷ Ω or less) was confirmed.

Therefore, the circuit in which the protruding conductor is generated in the defective mode (A) and the land in which the paste is bleeded in the defective mode (B) are detected by the electrical inspection and are reliably removed as defective products. I wish I could.

However, these failure modes (A),
(B) is room temperature (25 to 30 ° C.) and normal humidity (50
In the initial electrical inspection (short-circuit inspection) at 60%), the insulation resistance is 1.0 × 10 ⁸ Ω or more, and therefore the short-circuit inspection is judged to be non-defective.

Therefore, the present invention proposes a method of applying a high voltage pulse between two circuits which are short-circuited (potentially short-circuited) for a predetermined time.

Specifically, the pulse width is 150 to 500 V, preferably 250 V, and the pulse width is 0.3 ms to 0.5 ms (m
It is to apply a high voltage pulse of s: 1/1000 second) five or more times a plurality of times.

This promotes the deterioration of insulation between the two circuits which are short-circuited. Then, by applying a DC voltage, it is possible to confirm the presence or absence of a short circuit.

In the following, as a specific example, the failure mode (A)
The principle of the inspection method of the present invention will be described by comparing the non-defective product with the non-defective product.

As shown in FIG. 5, the interval between the good parts is
On the other hand, the gap in the defective mode (A), which is a potential short circuit portion, is 0.07 mm because the finished space of 0.04 mm has 20% of the protrusions 23b as shown in FIG.
It becomes 032 mm.

A case where a high voltage pulse is applied a plurality of times between the circuits of the non-defective part and the potential short-circuited part using the printed wiring board inspection apparatus of the present invention described in FIG. 1 will be described below. (1) First-time pulse voltage When a voltage of 250 V is applied between the two circuits as the first-time pulse voltage, the electric field strength of the non-defective part is 250 V / 0.
07mm = 3571.4V / mm, electric field strength of potential short circuit part is 250V / 0.032mm = 7812.5V /
mm, the electric field strength (7812.5 V / mm) at the potential short circuit portion becomes stronger as the distance between the circuits becomes shorter.

Since the electric field strength and the dissolution rate of copper constituting the conductor are in a proportional relationship, the amount of copper dissolved in the potential short-circuited portion is 2.18 times that in the non-defective portion.

The migration length is proportional to the amount of copper dissolved.

Here, for convenience of explanation of the principle of the inspection method of the present invention, the electric field strength of the non-defective portion is 3571.4V.
/ Mm, applied pulse width 0.5 ms (10000
It is assumed that the migration length of the non-defective part when applied is 0.001 mm.

In this case, the migration length of the potential short-circuited portion is 2.18 times 0.00218 mm (for the sake of convenience, the significant figures below the decimal point are not considered).

The respective gaps are narrowed / changed as follows.

Non-defective part: 0.0700 mm-0.001
mm = 0.0690 mm Potential short circuit part: 0.0320
mm-0.00218mm = 0.02982mm (2) 250V between the two circuits that are narrowed / changed in the case of the second pulse voltage (1)
When the voltage is applied (second time), the electric field strength in the non-defective part is 250 V / 0.0690 mm = 3623.2 V / m.
m, electric field strength of potential short circuit part is 250V / 0.02
982 mm = 8383.6 V / mm, the electric field strength (8383.6 V / mm) of the potential short-circuited portion becomes stronger than the electric field strength (3623.2 V / mm) of the non-defective portion.

Since the electric field strength and the copper dissolution rate are in a proportional relationship, the amount of dissolution in the potential short-circuited portion is 2.31 times that in the non-defective portion.

The migration length of the non-defective part is set to 0.
001014 mm (electric field strength of the above (1) 3571.4
Migration length at V / mm 0.001mm
Ratio) to 2.33.
This is double 0.002342 mm.

Each gap is further narrowed and changed as follows.

Non-defective part: 0.069 mm-0.0010
14 mm = 0.06798 mm, potential short circuit part: 0.
02982 mm-0.002342 mm = 0.0274
8mm (3) In case of the third pulse voltage (2)
When a voltage of 50 V is applied (third time), the electric field strength of the non-defective part is 250 V / 0.06798 mm = 3677.
5V / mm, electric field strength of potential short circuit part is 250V /
0.02748 mm = 9097.5 V / mm, the electric field strength of the potentially short-circuited portion (9097.5 V / mm) becomes stronger than the electric field strength of the non-defective portion (3667.5 V / mm).

Since the electric field strength and the copper dissolution rate are in a proportional relationship, the amount of dissolution in the potential short circuit portion is 2.47 times that in the non-defective portion.

The migration length of the non-defective part is set to 0.
001029 mm (electric field strength of (1) above 3571.4
Migration length at V / mm 0.001mm
Ratio) to the potential short circuit part 2.4.
It becomes seven times 0.002542 mm, and the respective gaps are further narrowed and changed as follows.

Non-defective part: 0.06798 mm-0.00
1029 mm = 0.06695 mm, potential short circuit:
0.02748mm-0.002547mm = 0.02
493 mm (4) 2 between the two circuits that are further narrowed and changed in the case of the fourth pulse voltage (3)
When a voltage of 50 V is applied (fourth time), the electric field strength of the non-defective portion is 250 V / 0.06695 mm = 3734.
1 V / mm, electric field strength of potential short circuit part is 250 V /
0.02493 mm = 1008.1 V / mm, the electric field strength (1008.1 V / mm) of the potential short-circuited portion is stronger than the electric field strength (3734.1 V / mm) of the non-defective portion.

Since the electric field strength and the copper dissolution rate are in a proportional relationship, the amount of dissolution in the defective portion is 2.68 as compared with that in the non-defective portion.
Doubled.

The migration length of the non-defective part is set to 0.
001045 mm (electric field strength of the above (1) 3571.4
Migration length at V / mm 0.001mm
Ratio) to the potential short-circuit portion.
It is eight times as large as 0.002800 mm, and each gap is further narrowed and changed as follows.

Non-defective part: 0.06695 mm-0.00
1045 mm = 0.05691 mm, potential short circuit part:
0.02493mm-0.002800mm = 0.02
213mm (5) In case of 5th pulse voltage (4)
When a voltage of 50 V is applied (fifth time), the electric field strength of the non-defective portion is 250 V / 0.05691 mm = 3793.
1 V / mm, electric field strength of potential short circuit part is 250 V /
0.02213 mm = 11296.9 V / mm, the electric field strength (11296.9 V / mm) of the potential short-circuited portion becomes stronger than the electric field strength (3793.1 V / mm) of the non-defective portion.

Since the electric field strength and the copper dissolution rate are in a proportional relationship, the amount of dissolution in the potential short-circuited portion is 2.98 times that in the non-defective portion.

The migration length of the non-defective part is set to 0.
001062 mm (electric field strength of (1) above 3571.4
Migration length at V / mm 0.001mm
Ratio) to the potential short-circuited part.
It is eight times as large as 0.003163 mm, and each gap is further narrowed and changed as follows.

Non-defective part: 0.05691 mm-0.00
1062mm = 0.06485mm, potential short circuit part: 0.022213mm-0.0031
63 mm = 0.01896 mm The interval between the circuits from the first pulse to the fifth pulse is 0.07 mm-0.04648 in the non-defective part.
5 mm = 0.00515 mm, the potential short circuit portion is 0.
032mm-0.01896mm = 0.01304mm
It is getting narrower.

From this, it can be seen that the amount of copper dissolved due to the migration of the potential short-circuited portion increases in series by a factor as compared with the non-defective portion.

As a result, the progress of migration in the potential short-circuited portion becomes faster as the pulse voltage is applied than in the non-defective portion, and the conductor gap becomes narrower in addition series. Going up.

By applying the pulse voltage a plurality of times, insulation deterioration is promoted, and eventually a short circuit occurs.

When a DC voltage of 200 V is applied between the circuits after the above-mentioned fifth pulse, the insulation resistance of the potential short-circuited portion becomes 100 MΩ or less, and the product is short-circuited and removed.

In the explanation of the principle of the present invention, the length of copper migration is explained to increase relatively as the electric field strength increases, but it does not increase linearly in practice.

This is because even if the amount of copper dissolved as migration is proportional to the electric field strength, the resistance value varies depending on the size and number of copper particles or the shape and density of the precipitate.

However, the progress of migration in the potential short-circuited portion is faster than that in the non-defective portion each time a pulse voltage is applied, and the conductor gap is theoretically the same as that in the addition series.

As the high-voltage pulse of the present invention, a pulse voltage of 150 to 500 V, specifically 250 V in the present embodiment, is applied and a current is passed, so that a high electrical energy is momentarily applied to the pattern to be inspected. However, it is not preferable for printed wiring boards.

That is, the land 12 as the pattern to be inspected of the multilayer printed wiring board to be inspected shown in FIG. 3 is a fine line, and the conductor is also relatively thin. 250V is applied to the land 12 as the pattern to be inspected.
If the pulse voltage of 1 is applied for a long time, thermal shock may be applied to the portion in contact with the inspection probe, and the land 12 and the insulating base material 13 around it may be destroyed.

Therefore, at a pulse voltage of 250 V,
The applied pulse width that was effective in the confirmation experiment was 0.3 ms
The range is 0.9 ms, and in the present embodiment,
0.5 ms (5 / 10,000 second) was adopted.

When the time is 0.3 ms or less, the occurrence of migration is small, and it is inefficient in promoting insulation deterioration. Further, if it is 0.9 ms or more, the occurrence of migration is large, and insulation deterioration may proceed even in non-defective parts.

Further, if the pulse voltage is set to 500 V or more, even if the applied pulse width is set to a minimum (0.01 ms or less), dielectric breakdown due to high voltage or land pattern burning due to heat of contact resistance may occur. There is.

On the other hand, when the pulse voltage is set to 150 V or less, the effect of insulation deterioration is reduced, the inspection efficiency is poor, and a potential short circuit may be missed.

Although the present invention shows the case where the DC voltage is alternately applied to the two circuits to promote the insulation deterioration, the same effect can be obtained when the AC voltage is applied to the two circuits. . However, in this case, the voltage is set in consideration of the frequency of the AC power supply and each frequency.

A potential short circuit (commonly called whisker short 3a, 3) which may occur by brush polishing the conductor circuit.
It is particularly effective to apply an AC voltage in the case of detecting (c).

In this embodiment, the DC voltage after applying the pulse voltage is 200 V, but the length of the conductor is
It is not limited to this depending on the type of the insulator.

[0096]

As described above, according to the present invention, by applying a high voltage pulse between two conductor patterns for a predetermined time, insulation deterioration is promoted, a potential short circuit is detected, and it is removed to remove electrons. This has the effect of improving the reliability when the device is used.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electric circuit according to an embodiment of the present invention.

FIG. 2A is a diagram showing a pulse voltage applied between the circuits in the embodiment of the present invention. FIG. 2B is a diagram showing a pulse voltage applied between the circuits in the embodiment of the present invention.

FIG. 3 is a sectional view of a multilayer printed wiring board according to an embodiment of the present invention.

FIG. 4 is a diagram showing a manufacturing process of the printed wiring board in the embodiment of the present invention.

FIG. 5 is a sectional view showing a non-defective part in the embodiment of the present invention.

FIG. 6 is a sectional view showing a defective portion according to the embodiment of the present invention.

FIG. 7 is a diagram showing occurrence of whisker shorts in two conductor patterns.

FIG. 8 is a diagram showing a state of protrusions in two conductor patterns.

FIG. 9 is a diagram showing a state where two conductor patterns are about to break.

[Explanation of symbols]

3a, 3c Beard short 3b protrusion 4a-4d Land portion contacted with the probe to be inspected 5a-5d switch 6a, 6b Ground (ground) 7 Voltmeter 11 Copper foil 12 lands 13 Insulation board 14 Conduction hole 15 prepreg 16 PET film 17 Conductive paste

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiaki Tanaka             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Makiko Sasaki             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2G014 AA03 AA13 AA17 AB59 AC10                 5E317 AA11 AA24 BB01 BB12 BB14                       CC25 GG20

Claims (15)

[Claims] 1. A printed wiring board comprising: a step of applying a pulse voltage having a predetermined pulse width a plurality of times between at least two conductor patterns of the printed wiring board; and a step of applying a DC voltage between the conductor patterns. Inspection method. 2. The method for inspecting a printed wiring board according to claim 1, wherein a direct current voltage is alternately applied to the two conductor patterns as the pulse voltage. 3. The method for inspecting a printed wiring board according to claim 1, wherein an alternating voltage is applied to the two conductor patterns as the pulse voltage. 4. The method for inspecting a printed wiring board according to claim 1, wherein the pulse voltage is 150 to 500V. 5. The predetermined pulse width is 0.3 ms to 0.9.
The printed wiring board inspection method according to claim 1, wherein the inspection method is ms. 6. The step of confirming the presence or absence of continuity is based on an insulation resistance value as a criterion, and the insulation resistance value is 1.0 × 10 ⁷ Ω or less.
The method for inspecting printed wiring boards described in. 7. The distance between the conductor patterns is at least 0.
04 mm, and the distance between the conductor patterns is 2
The printed wiring board inspection method according to claim 1, wherein 0% or more of the protruding conductors are present. 8. The printed wiring board according to claim 7, wherein the pulse voltage is 250 V, the predetermined pulse width is 0.5 ms, and the pulse voltage is applied 5 times or more. Inspection method. 9. The method for inspecting a printed wiring board according to claim 1, wherein at least one of the two conductor patterns is a connection land. 10. A conduction hole is provided immediately below the connection land,
The method for inspecting a printed wiring board according to claim 9, wherein the conductive hole is formed by filling a through hole with a conductive paste and curing the conductive paste. 11. The method for inspecting a printed wiring board according to claim 10, wherein the through holes are formed by laser processing after attaching PET films to both surfaces of the sheet-shaped resin-impregnated base material. 12. The method for inspecting a printed wiring board according to claim 10, wherein the conductive paste contains silver powder or copper powder. 13. A plurality of inspection terminals provided at the same position as an inspection pattern on a printed wiring board, at least two terminals being one set, a pulse voltage generating means between the two terminals, and the pulse. A printed wiring board inspecting apparatus comprising: a means for stopping a voltage; a means for applying a constant voltage between the two terminals; and a means for detecting a resistance value between the two terminals. 14. The printed wiring board inspecting device according to claim 13, wherein the means for generating the pulse voltage between the two terminals alternately generates the pulse voltage between the two terminals. 15. The printed wiring board inspection apparatus according to claim 13, wherein the means for detecting the resistance value between the two terminals is replaced with a means for detecting the current value between the two terminals.