JP2000155149A - Device, method, jig for inspecting circuit board continuity, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve S/N ratio by decreasing the impedance of a current path to be inspected. SOLUTION: At one of both terminals of a pattern line on a substrate to be inspected, a coupling capacitor is formed without contacting, and an inductance 450 and a lead line are connected to the capacitor. The other terminal is applied with an AC inspecting signal by means of contact method via a lead wire. A resonance circuit is formed of the capacitor, an inductance 450 and a pattern line, and with the inductance lowered, an output signal is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board continuity inspection apparatus used for inspecting a circuit board having a fine wiring pattern, a method thereof, and a jig used for the inspection.

[0002]

2. Description of the Related Art It is known that a method for inspecting a circuit board includes a pin contact method and a non-contact method. In the pin contact method, as shown in FIG. 1, pin probes are respectively brought into direct contact with both ends of a conductor pattern to be inspected, a current is applied to one pin probe, and a voltage value detected by the other pin probe is used. The continuity test between both ends is performed by obtaining the resistance value of the conductor pattern.

[0003] This pin contact method has an advantage that the SN ratio is high because the pin probe is brought into direct contact. However, on the other hand, inspecting a fine-pitch substrate is difficult to pin itself,
In addition, positioning for bringing the pins into contact with the target pattern becomes difficult. Further, there is a disadvantage that it is difficult for the pin probe itself to have an initial accuracy due to the contact, and a running cost due to probe replacement occurs.

[0004] On the other hand, in the non-contact / contact combined type, as shown in FIG. 2, one end of a conductor pattern to be inspected is brought into direct contact with a pin probe (or non-contact through capacitive coupling).
To apply a test signal containing an AC component and detect the test signal at the other end via capacitive coupling. In this non-contact / contact combination method, since it is not necessary to contact the pin probe with at least one end of the pattern line,
Since the positioning accuracy can be roughened and the pin probe can be used in common for a plurality of pattern lines, the number of pin probes can be reduced, and there is a fear of abrasion. Therefore, this is effective for a substrate having fine patterns.

[0005]

However, in the non-contact / contact combined type, the impedance is high (several MΩ to several GΩ) because the value of the coupling capacitance is small.
There is a drawback that a defective portion of about 0Ω to 100Ω cannot be detected. Therefore, in the related art, the non-contact / contact combined method has a number of advantages, but has a high impedance. However, the fact that the method is practiced only for the above-mentioned substrate, and that the pin probe and its jig are required to have high precision has been a hindrance to the cost reduction of the non-contact / contact combined type.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-resistance state by reducing the impedance of a circuit formed on a substrate by resonating the oscillation of the circuit formed on the substrate. In addition, the present invention proposes a continuity inspection device capable of inspecting a low-resistance continuity state.

According to the present invention, an electrode is brought close to one end of a pattern to be inspected, a capacitor C is formed between the end and the electrode, and an inductive element L is connected to the capacitor C.
An inspection signal (frequency f) containing an AC component is applied to the other end of the pattern line via a pin probe. When L is appropriately adjusted to lower the impedance of the resonance circuit, for example, when L is adjusted so that the following equation (1) is satisfied, 2f · L = (１ ／) f · C (1) ) Holds, L = (1/4 ² ) × f ² × C (2) In other words, if L in equation (2) is set, the impedance of the circuit becomes zero and the output voltage V Indicates the maximum value at this time. Assuming that the output voltage V when the resonance frequency f _R is applied using a reference circuit board (a circuit board that has been confirmed to have no disconnection, etc.) is V _R , the actual circuit board to be inspected is used. output voltage V _X of, since it is expected that the circuit approaches the resonance condition, is expected to show a large value.

The relationship between the operating frequency f _R that can resonate and the inductive element L is, for example, as follows.
When the 0fF is, f _R = 10 kHz If L = 25.3kH or f _R = 10 MHz if L = 25mH or f _R = 50 MHz if L = 1 mH, or f _R = 100 MHz if L = 250μH,, Becomes

Elements for controlling resonance include the frequency f of the input test signal, the coupling capacitance C, and the inductance L of the inductive element. For example, the size of the electrodes is fixed, and the proximity distance is kept constant during measurement. In such a case, the capacitance C is expected to be, for example, about 15 fF. At this time, the impedance can be made substantially zero by setting the value of the inductive element L to about 250 μH to 1 mH and preparing an AC signal source of about 50 MHz to 100 MHz.

A continuity test for inspecting continuity between the first and second terminals of a substrate provided with a pattern line having first and second terminals on the substrate according to claim 1. The device is connected to the first terminal, a capacitive coupling unit having a coupling capacitance in a non-contact manner and having a coupling capacitance, and the capacitance coupling unit to form a resonance circuit with the capacitance of the capacitive coupling unit. An inductive element, a first lead connected to the inductive element, probe means connected to a second lead and in contact with the second terminal, and a first lead connected to the second lead. Signal input means for inputting a test signal containing an AC component to one of the lead wires, and signal detection for detecting the output of the test signal to the other of the first lead wire and the second lead wire Means.

The mounting position of the inductive element can be variously changed. According to a second aspect of the present invention, there is provided a continuity inspection device for inspecting continuity between the first and second terminals of a substrate provided with a pattern line having first and second terminals on the substrate. A probe means directly in contact with the first terminal, an inductive element connected to the probe means, a first lead wire connected to the inductive element, and a second lead wire connected to the second lead wire;
Capacitive coupling means for capacitively coupling with the second terminal in a non-contact manner and having a coupling capacitance, and a test signal containing an AC component is input to one of the first lead wire and the second lead wire. And a signal detecting means for detecting the output of the inspection signal on one of the first lead wire and the second lead wire.

[0012] A coupling capacitance may be formed at both the first terminal and the second terminal. According to a third aspect of the present invention, there is provided a continuity inspection device for inspecting continuity between the first and second terminals of a substrate provided with a pattern line having first and second terminals on the substrate. A first capacitive coupling unit that has a coupling capacitance in a non-contact manner with the first terminal and has a capacitive coupling, and the first capacitive coupling unit that forms a resonance circuit with the capacitance of the first capacitive coupling unit. An inductive element connected to the means, a first lead connected to the inductive element, and a second lead connected to the second terminal, the second terminal having a coupling capacitance in a non-contact manner; A second capacitive coupling means for capacitively coupling, a signal inputting means for inputting a test signal containing an AC component to one of the first lead wire and the second lead wire, Signal detecting means for detecting the output of the inspection signal on one of the other of the second lead wires; And wherein the Rukoto.

The object of the present invention can also be achieved by a continuity inspection jig provided with a first terminal group and a second terminal group separated by a predetermined distance. This jig for continuity inspection may be a first terminal group or a part of the first terminal group.
A lead wire is connected to an end of the first terminal group so that a test signal for continuity test can be applied, and a second end of each of the first terminal groups or a part of the first terminal group contacts a substrate to be inspected. And one or more inductive elements are connected to each or a part of the second terminal group, and a second end of each or a part of the second terminal group is provided. Each of the portions is provided with an electrode for forming a coupling capacitance in a non-contact manner with the wiring pattern of the substrate to be inspected.

The above object can also be achieved by the continuity inspection method according to claim 18. The method comprises the steps of: providing a substrate provided with a pattern line having first and second terminals on the substrate;
A continuity inspection method for inspecting continuity between said first and second terminals, wherein a predetermined electrode is brought close to said first terminal to form a coupling capacitor, and a predetermined inductive element is connected to said electrode. Then, by connecting a first lead wire to the inductive element and connecting a second lead wire to the second terminal, the first lead wire, the inductive element, the electrode, the coupling capacitor, Forming a resonance circuit with the first terminal, the pattern line, the second terminal, and the second lead; and an inspection signal including an AC component in one of the first lead and the second lead. And a detection step of detecting the output of the inspection signal in one of the first lead wire and the second lead wire.

[0015] In order to achieve the above object, a nineteenth aspect is provided.
A continuity inspection method for inspecting continuity between the first and second terminals of a substrate provided with a pattern line having first and second terminals on the substrate; The first lead wire is in direct contact with the second terminal and has a coupling capacitance in a non-contact manner with the second terminal through a device, and the second lead wire is inductively coupled to the second lead terminal. Forming a resonance circuit with the conductive element, the first terminal, the pattern wire, the second terminal, the electrode, the coupling capacitor, and the second lead; and selecting one of the first lead and the second lead. An application step of applying an inspection signal containing an AC component to one of them, and a detection step of detecting the output of the inspection signal in one of the first lead wire and the second lead wire. Features.

[0016] In order to achieve the above object, a twentieth aspect is provided.
The method of inspecting continuity between the first and second terminals of a substrate provided with a pattern line having first and second terminals on the substrate may include the step of connecting to a first lead wire. The inductive element is capacitively coupled to the first terminal via a first electrode in a non-contact manner, and a second lead wire is capacitively coupled to the second terminal via a second electrode in a non-contact manner. By coupling, the first lead, the inductive element, the first electrode,
Coupling capacitance, first terminal, pattern line, second terminal, second terminal
Forming a resonance circuit with the electrodes, the coupling capacitance, and the second lead wire; and applying an inspection signal containing an AC component to one of the first lead wire and the second lead wire. A detecting step of detecting an output of the inspection signal in one of the first lead wire and the second lead wire.

Comparing the conventional example having only the coupling capacitance with the above configuration, when the inductance L is not provided, the coupling capacitance C is set to, for example, 10 fF and the operating frequency is set to 10 kHz.
Assuming that z, the output impedance dance of the circuit is 1 / (2fC) = 1 / (2 × 3.14 × 10 ³ × 10 ^-15 ) = 1.6 G
Ω, and it is almost impossible to measure the resistance of the pattern. If the frequency f is 100 MHz, the impedance can be reduced to 1 / (2 x 3.14 x 10 ⁶ x 10 ^-15 ) = 159 kΩ, but raising the frequency to such a high frequency is realistic in terms of cost. is not. That is, it is important to select an optimal frequency.

Therefore, the present invention relates to a continuity inspection method.
According to (4), the method further includes a reference frequency determination step, wherein the reference frequency determination step is performed by changing the frequency of the inspection signal to a predetermined reference substrate while changing the frequency of the inspection signal prior to the application step. A first terminal and a second terminal of the reference substrate.
A determining step of determining a resonance frequency of a pattern line between terminals of the first and second lead wires, using the resonance frequency as a frequency of a test signal. It is characterized by applying.

The frequency change range must be determined in advance. In particular, according to claim 25, in the determining step, the frequency of the inspection signal for the reference substrate is changed within a predetermined range around a standard frequency previously determined based on the constant of the inductive element. It is characterized by. In some cases, a difference occurs between a reference substrate and a substrate to be actually inspected, and the difference may cause an apparent difference in a detection signal. In order to compensate for this error, in the method according to claim 26, in the applying step, the frequency of the inspection signal for the substrate to be inspected is set within a predetermined range around the frequency determined in the determining step. Fluctuate

[0020]

FIG. 3 is a diagram illustrating the principle of operation of a preferred embodiment of the present invention. Reference numeral 100 denotes a circuit board to be inspected, on which pattern lines 101 are laid. The pattern line 101 has two ends 102, 10
6, and in principle, the length and the pitch between the ends 102 and 106 are not limited. A pin probe 103 is brought into contact with the end 102 of the pattern 101 (in principle, the probe 103 may be capacitively coupled to the end 102 without contact), and the probe 103 receives an inspection signal containing an AC component. Applied.

In the vicinity of the end 106 of the pattern 101,
The electrode 107 is arranged. A space 105 is formed between the electrode 107 and the end 106, and this space forms the capacitance C. An inductance L is connected in series to the electrode 107, and an output voltage V at the inductance L is monitored. When the frequency f of the input inspection signal is selected to be a value f ₀ at which the distributed constant circuit does not hold on the inspection target substrate, the condition for lowering the circuit impedance is as follows: The inductance L is selected such that (1/4 ² ) × f ₀ ² × C (3)

Whether the inductance L is provided on the electrode 107 side as shown in FIG. 3 or on the pin probe 103 side is not essential. Therefore, the inductance L may be provided between the pin probe 103 and the AC power supply 104 in FIG. Also, in FIG.
The electrode 107 may be moved to the AC power supply side. In such a modified embodiment, as shown in FIG.
Has been moved to the AC power supply side. Also in the example of FIG. 4, since the capacitance C and the inductance L are in series,
Equation (2) or equation (3) is the condition for lowering the impedance.

In a further modified embodiment, as shown in FIG. 5, an electrode 1 is further provided on the pin probe side of the embodiment shown in FIG.
08 (coupling capacitance C ₁ ). Assuming that the coupling capacitance of the electrode 107 is C ₂ , the inductance L is calculated as follows: L = (１ ／ ² ) × f ₀ ² × [(C ₁ C ₂ ) / (C ₁ + C ₂₎ )] ... Select according to (4). Since the combined capacitance (C ₁ C ₂ ) / (C ₁ + C ₂ ) is reduced as compared with the individual capacitances (C ₁ , C ₂ ), the embodiment of FIG. 5 is different from the embodiment of FIG. Thus, as long as the same inductance L is used, the operating frequency f must be increased, but the effect that the electrode 108 side does not require high positioning accuracy is obtained.

In both the embodiment of FIG. 4 and the embodiment of FIG. 5, the input side of the inspection signal and the monitor side of the output signal are arbitrary.

[0025]

EXAMPLES Examples which further embody the above embodiment will be described in detail below. This embodiment is an example of an inspection apparatus for inspecting a circuit board on which a plurality of fine pitch pattern lines are laid. FIG. 6 shows an example of a circuit board 200 to be inspected. That is, the circuit board 200 is provided with a plurality of pattern lines, and the purpose of the inspection apparatus of the embodiment is to inspect the continuity of each pattern line. Substrate 200
In the drawing, pattern lines are laid from left to right on the drawing, and the pitch between adjacent pattern lines on the left side of the substrate is such that a pin probe can be set up. The pitch between adjacent pattern lines on the right side of the substrate 200 is
It is assumed that there is an interval such that two electrodes of adjacent pattern lines do not contact each other.

FIG. 7 is an example of a jig 300 created specifically for the circuit board 200 of FIG. The reason why the jig is dedicated is that the substrates to be inspected vary widely. That is, the shape and pitch interval of the pattern line differ for each substrate,
This is because the determination as to whether a pin probe or an electrode can be provided for each pattern line differs for each substrate. If the pin probe cannot be provided on the input side of the inspection signal, the method shown in FIG. 5 must be used, and if the electrodes cannot be provided on the individual pattern lines, a plurality of pattern lines must be used. This is because a method of providing a common electrode has to be adopted. Therefore, the number and arrangement positions of the pin probes and the number and arrangement positions of the electrodes are inevitably varied. Therefore, a jig dedicated to the substrate is used from the viewpoint of work efficiency.

Referring to FIG. 7, the main body of jig 300 is made of, for example, an acrylic plate or the like.
It is created according to the shape of. The substrate 200 in the example of FIG.
A plurality of pin probes 310 (tips of which are sharpened so as not to damage the substrate) are provided on the left side of the jig 300 on the main body of the dedicated jig 300, and are provided on the right side of the jig 300. A predetermined position of the electrode 350 provided for each pattern line is set. Pin probe 3
A lead wire is connected to each of the electrodes 10 and the electrodes 350.

FIG. 8 is a block diagram showing the configuration of the inspection system 400. This inspection system 400 is an example in which the aforementioned jig 300 is used. Controller 410 controls the overall sequence and control procedures of the system. That is, the controller 410 controls a circuit 430 for generating a test signal, a 1: N multiplexer, an M: 1 multiplexer, and an adapter 480 including an inductance 450, a resistor 460, and an A / D converter 470.

The system shown in FIG. 8 is intended for the circuit board shown in FIG.
Receives a test signal and distributes the signal to N analog switches. N analog switches are required for the number of pin probes on the board 200. M multiplexers 440 (equal to the number of output pins, typically M = N)
Of the analog switch outputs is selected and output to the adapter 48.

The adapter 480 is connected to the substrate 200 to be inspected.
Since each has an inherent inductance 450 and resistance 460, a detachable adapter configuration was adopted. Next, the ninth
A control procedure of the present inspection system will be described with reference to FIGS. In this control procedure, the impedance of each pattern line of the reference work is measured by measuring a reference work (a work confirmed to have no defect such as disconnection) (the control procedure in FIG. 9). By measuring the impedance of the work to be inspected and comparing the impedance of the work to be inspected with the impedance of the reference work, a defective portion (disconnection and half-short) is detected (excluding a defective board based on the detection). (FIG. 10).

In step S2 of FIG. 9, a reference work is set. In step S4, the jig 300 is set on the reference work. With this set,
The plurality of electrodes provided on the jig are in non-contact proximity to the end of the pattern to be inspected. In step S6, the counter N and the counter M are initialized to one. In step S8, the frequency of the inspection signal from the transmitter 430 is set to −10% of the reference frequency f ₀ , that is, (1-1 / 10) · f ₀ = (9/10) · f ₀ . In step S10, the multiplexer 42
0 and 440 are set, and a test signal having a frequency f ₀ is applied to the pattern line selected by the counters N and M.
At this time, only the analog switch designated by the counter N is turned on, and the other switches are shunted to the ground side. In the multiplexer 440, only the analog switch designated by the counter M is turned on, and the other switches are shunted to the ground. As a result, the N-th analog switch is turned on, the inspection signal is applied to the pattern line specified by the values N and M, and the output signal of that line is sent to the adapter 480 via the M-th analog switch of the multiplexer 440. Is entered.

The output signal V _NM of the pattern line NM detected by the adapter 480 is measured in step S12,
It is stored in a predetermined memory of the controller 410. In step S14, the frequency of the inspection signal is increased by Δf. According to the test signal of the increased frequency, step S
At 12, the output voltage is measured. This operation is performed in step S1.
At 6, the process is repeated until the frequency f exceeds 11/10 · f ₀ . A plurality of measurement values V _NM obtained by repeating steps S12 to S16 are expected to show peak values as shown in FIG. At this time, the output signal value is V _{RN M} (the subscript R represents the reference), and the frequency is f
Store as _RNM in the memory of the controller. In step S22, the current path NM is _calculated from the reference force signal value V _RNM.
Is obtained.

These steps S8 to S24
By repeating the above operations, the reference frequency f _RNM for giving the reference force signal value V _RNM for an arbitrary pattern line NM
And the impedance Z _RNM of the current path NM. These data are stored in the memory as a set, and can be retrieved from the memory by the argument NM.

According to the first control procedure, the work to be inspected is measured. That is, in step S30, the work to be inspected is set. In step S32, a jig is set for this work. In step S34, the counters N and M are initialized. In step S36, a combination of the reference frequency f _RNM and the reference impedance Z _RNM is read from the aforementioned memory. In step S38, the inspection signal of the reference frequency f _RNM is applied to the NM pattern line of the target substrate. In step S49, by measuring the output signal V _NM from this pattern line, the Z of the current path NM is measured.
Calculate _XNM . In step S42, the impedance Z _NM of the work is calculated based on Z _NM = | Z _XNM Z _RNM | In step S44, step S
The impedance Z _NM calculated at 42 is a predetermined threshold value TH _NM
It is determined whether or not exceeds. If the impedance greatly exceeds the threshold value, the current path NM is determined to be defective (step S46), and if not, it is determined to be normal.

In steps S36 to S52,
The above determination is made for all current paths. The board is determined to be normal / defective if at least one defective current path exists (although not limited to this), the board is determined to be defective. <Other Embodiments> In the above embodiment, as shown in FIG. 3 and the like, the coil (L) as an inductive element is connected in series with the coupling capacitance (C) formed between the electrode and the circuit board. However, as shown in FIG. 13, it is also possible to connect L in parallel with C and measure the voltage between C and ground. With this connection method, the resonance intensity can be increased, and the system configuration shown in FIG. 8 can be used substantially as it is in the control procedure shown in FIGS. 9 and 10.

At this time, in order to increase the resonance intensity, the current detection resistor is removed. Further, similarly to the above-described embodiment, the correlation between the output voltage and the resistance value for various paths is obtained in advance by using the reference substrate. <Specific Example of Sensor> The shape of the sensor shown in FIGS. 5 and 6 is conceptualized, and it is usually preferable that the shape of the sensor electrode conforms to the shape of the path pattern to be inspected. FIG. 14 shows an example of a circuit board 500 to be inspected.

In FIG. 14, reference numeral 501 indicated by a broken line
Is an electronic device (LS) to be mounted on the board to be inspected in the future.
I etc.). The electronic device 50 is placed on the substrate 500.
Path patterns 500a, 500b, 500d, and 500e to which one input / output pin (not shown) is to be connected in the future are provided. In FIG. 15, the route patterns 500a.
10 shows a sensor assembly 600 for performing the inspection of FIG.
That is, in FIG. 15, the sensor electrode plate itself is a rectangular conductive plate 620 with a part cut away. Conductive plate 6
Reference numeral 20 is surrounded by a ground electrode plate 610. Also,
The inside of the rectangular sensor electrode plate 620 is cut out, and the ground electrode plate 630 is formed inside the cutout. Part of the rectangular sensor electrode plate 620 is 6
It is notched at 40 and has a C-shaped shape. Notch 640 forms a line connecting electrode plates 610 and 630 to keep ground electrode plates 610 and 630 at the same ground potential. Thus, the sensor electrode plate 620 is sandwiched between the ground electrode plates 610 and 630 functioning as a shield.

The coil L is set between the sensor electrode plate 620 and the output terminal line 650, as shown in FIG. The above-described sensor assembly 600 is brought closer to the surface of the circuit board 500 to be inspected on which the pattern paths 500a are provided. In the example of FIG. 15, since the pattern paths 500a are provided on the lower surface of the substrate 500, the sensor assembly 600 is moved closer to the lower side of FIG. In FIG. 15, reference numeral 700 denotes an opposite side of the substrate of the sensor assembly 600 on which the sensor electrodes are provided (first side).
It is a shield plate provided on the lower side in the example of FIG. 5). The shield plate 700 has substantially the same size as the ground electrode plate 610 of the sensor, but is partially provided with a notch 730 as shown in FIG. The notch 730 substantially matches the pattern of the sensor electrode plate 620. That is, the sensor electrode plate 620 exerts a shielding effect by being sandwiched between the ground electrode plates 610 and 630 on the same surface as the sensor, and has a shield plate corresponding to the ground electrode plates 610 and 630 on the opposite surface. 710 and 720 are provided, and the S / N ratio is improved by not providing a shield plate corresponding to the sensor electrode plate 620.

The reason why the sensor electrode plate 620 is made substantially rectangular (or C-shaped) is that a plurality of ends of the path patterns 500a are rectangular sides on the substrate to be inspected shown in FIG. This is because they are arranged so as to form. Therefore, when the distribution of the end portion of the path pattern to be inspected has an arbitrary shape, the shape of the sensor electrode plate is created according to the distribution shape. For example, when the ends of the plurality of path patterns 500a are distributed along the entire sides of the triangle, for example, the shape of the sensor electrode plate has a width enough to secure the coupling capacitance C, What is necessary is just to have a strip | belt shape along each side of the said triangle.

<Design Method of Inspection System> As is clear from the description of the above embodiment, the main focus of the inspection system is as follows.
An object of the present invention is to raise the output voltage level by lowering the impedance of the entire circuit by generating a resonance state.
In order to generate a resonance state, it is necessary that a predetermined condition is satisfied. Factors affecting the condition include: coupling capacitance C (that is, the line width of the path pattern, the area / width of the sensor electrode plate, the pattern -Induction constant L-Applied frequency f. Obviously, since the frequency f can be easily changed electronically and electronically, it is suitable for finding a resonance point as employed in the above embodiment. However, the coupling capacitance C
Is generally small, so that a resonance state may be obtained at a high frequency, but since a high resonance point causes operation instability and signal leakage in the entire inspection system, it is not appropriate to use an excessively high frequency f. Not preferred.

Further, it is generally not allowed to change the line width or length of the path pattern of the inspection target substrate which affects the coupling capacitance C. Therefore, the design method of the system to be proposed is as follows: I: First, the coupling capacitance C is set to 50 fF to 1 pF in consideration of the line width and length of the path pattern of the inspection target substrate and the size and area of the sensor electrode. The sensor electrode is designed to be within the range. II: Next, the value of the inductive element L is determined so that the resonance frequency, that is, the fundamental frequency of the transmitter falls within the range of 5 MHz to 10 MHz. According to experiments, the inductive element is between 20 mH and 25
A range of μH is preferred.

In the inspection system designed by the above design method, the whole system is stable at high frequencies, and the optimum resonance point can be easily found. <Modifications> M-1: Any of the inspection principles of the first to third embodiments can be applied to the inspection system of the above embodiment. M-2: In the above embodiment, when the reference frequency is obtained from the reference work, ± 10% of the standard frequency f ₀ (± δf
), And the peak is detected, but the variation range δf is not limited to this.

For example, when the number of test substrates to be continuously measured is diversified and the reference frequency varies widely, it is necessary to increase the variation ± δf for searching for a peak.
Therefore, when the reference frequency is expected to be significantly different between a plurality of substrates to be continuously measured or a plurality of pattern lines of one substrate, it is necessary to increase the variation width ± δf in advance. However, increasing the variation width ± δf increases the time required for inspection, and therefore, it is necessary to determine the variation in consideration of this point. M-3: In the above embodiment, an electrode is provided for each of the plurality of current paths (pattern lines), but the present invention is not limited to this. In particular, when the pitch of the pattern battleship on the output side is narrow, it is necessary to provide a common electrode for a plurality of pattern lines. Thus, the number of electrodes can be reduced, so that the necessity of positioning the jig with high precision is reduced.

FIG. 12 shows a configuration in which all the pattern lines of one inspection board are inspected by two electrodes 107a and 107b. One analog switch is required for each electrode. In the example of FIG. 12, the electrode 107a
Is different from the reference frequency of the pattern line covered by the electrode 107b.
Each was provided with an inductance 450a, 450b.
If the reference frequencies are not expected to differ significantly,
The inductance can be reduced to one, and if it can be reduced to one, the inductance can be moved to the adapter side differently from FIG. 12, as in the previous embodiment. M-4: The number of inductances L depends on the operating frequency f. When the frequency f is high, the installation position of the inductance L is preferably sufficiently close to the substrate to be inspected.
Therefore, in such a case, a plurality of inductances having the same value need to be located at all stages of the analog switch in the multiplexer 440. M-5: In the above embodiments and examples, the frequency f was changed to make the resonance state appear. However, the present invention is not limited to this. For example, the coupling capacitance C or the inductance L was changed. May be.

For example, when changing the inductance L, the inductance chip having a plurality of taps is connected to the adapter 4.
80 or within the multiplexer 330, or
It is provided directly near the electrode. The reason why the coupling capacitance C needs to be changed is, for example, to match the resonance frequency to a plurality of pattern lines (a plurality of current paths) when the sizes of the electrodes are different. M-6: The value of the inductance L should be determined according to the frequency of the transmitter used. In the present invention, it is essential to measure the impedance in the resonance state, and as long as the resonance state can be obtained, it can be achieved by changing the frequency f, changing the coupling capacitance C, or changing the inductance L. However, increasing the frequency increases the leakage current in the entire circuit board, causing a problem that the measurement accuracy is reduced. Therefore, in order to obtain a resonance state without increasing the resonance frequency, the value of the inductance L should be increased. In the above embodiment, the resonance frequency is set to about 5 MHz.

It is also possible to change the coupling capacitance to change the resonance state. In this case, since it is not preferable to change the size of the coupling capacitor C by changing the electrode, for example, only when the resonance is large electrode coupling capacitance C ₀ by larger electrodes becomes excessive, separately, the resonant amplitude It is also necessary to provide an attenuating capacitor C _X in series with C ₀ to avoid this. M-7: In the above embodiment, it is assumed that a peak is found while the frequency is changed within a range of ± 10% in steps S12 to S16. In practice, peaks may not be found. Therefore, the ninth
It is proposed to modify the flowchart in the figure as follows.

That is, in one modified example, a frequency at which a maximum value within a range of ± 10% is given is regarded as a resonance point and the frequency is used as a reference frequency, instead of detecting a peak. In the second modification, if a peak value, that is, a maximum value is not found, step S16 is changed so as to expand the fluctuation range until a maximum value is found. M-8: In the procedure for inspecting the work to be inspected in the above embodiment (FIG. 10), the reference frequency f _RNM obtained using the reference work was used. This is because it is assumed that no displacement occurs when the reference work and the actual inspection work are respectively mounted on the jig. However, it may be difficult to actually reduce the displacement to zero. In such a case, if the correction of the positional deviation is not taken into consideration, an increase in the impedance (apparent increase) due to the positional deviation may be erroneously determined as an increase in the impedance due to a defective pattern line. Therefore, it is proposed to modify the control procedure as follows.

That is, the procedure of peak detection applied to the reference work is also applied to the inspection of the actual work. Specifically, Steps S12 to S1
Steps similar to step 6 are replaced with step S38 (FIG. 10). At this time, f ₀ in step S16 is replaced with f _RNM read in step S36. In other words, the peak frequency at which the resonance state is generated is searched for by varying the range of ± 10% (not limited to ± 10) around f _RNM . Such a change can effectively cope with a displacement. M-9: In the present invention, the inductive element, that is, the inductance L may actually have various shapes. However, when the operating frequency is relatively high, care must be taken in mounting the inductance. M-10: In the present invention, the inductive element, that is, the inductance L may actually have various shapes. However, if the operating frequency is relatively high, care must be taken in mounting the inductance. FIG. 13 illustrates the mounting state of the coil when the inductance is a coil. M-11: The test signal is not limited to a sine wave as long as it has an AC component, and may be, for example, a pulse train or a single pulse.

[0049]

As described above, according to the circuit board continuity inspection apparatus and method of the present invention, it is possible to lower the circuit impedance by causing a resonance state at a low frequency to appear, and as a result, the output By improving the signal-to-noise ratio of a signal, a highly accurate continuity test can be performed.

In particular, since the non-contact method can be adopted while maintaining the use of the contact method, the number of probes can be reduced, which greatly contributes to cost reduction.
In addition, a low resistance value of, for example, about 10 to 100 Ω could be measured as a conductive state.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a contact-type inspection device according to a conventional example.

FIG. 2 is a diagram showing a basic configuration of a non-contact type inspection apparatus according to a conventional example.

FIG. 3 is a diagram showing a basic configuration of an inspection apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing a basic configuration of an inspection apparatus according to another embodiment of the present invention.

FIG. 5 is a diagram showing a basic configuration of an inspection apparatus according to still another embodiment of the present invention.

FIG. 6 is a top view illustrating an appearance of a substrate to be inspected as an example used in the apparatus of the embodiment.

FIGS. 7A and 7B are a side view and a top view showing the appearance of a jig used in the apparatus of the embodiment.

FIG. 8 is a diagram showing a system configuration of an embodiment apparatus.

FIG. 9 is a flowchart illustrating an overall control procedure in the apparatus according to the embodiment.

FIG. 10 is a flowchart for explaining an overall control procedure of the embodiment apparatus.

FIG. 11 is a graph illustrating a peak search operation in the apparatus according to the embodiment.

FIG. 12 is a block diagram showing a partial configuration of an inspection device according to a modification.

FIG. 13 is a diagram showing a connection relationship between an inductive element L and a coupling capacitor C according to another embodiment.

FIG. 14 is a view showing a specific example of a substrate to be inspected.

15 is a diagram showing a configuration of a sensor electrode plate for inspecting the substrate of FIG. 14, including a front view and a side sectional view.

Claims (29)

[Claims] 1. A continuity inspection device for inspecting continuity between said first and second terminals on a substrate provided with a pattern line having first and second terminals on said substrate, wherein said first terminal A capacitive coupling means having a coupling capacitance in a non-contact manner and having a capacitive coupling; an inductive element connected to the capacitive coupling means so as to form a resonance circuit with the capacitance of the capacitive coupling means; A first lead wire connected to the element, a probe connected to the second lead wire and in contact with the second terminal; and one of the first lead wire and the second lead wire, Signal input means for inputting a test signal containing an AC component, and signal detection means for detecting an output of the test signal on one of the first lead wire and the second lead wire. Circuit board continuity inspection device. 2. A continuity inspection device for inspecting continuity between said first and second terminals on a substrate provided with a pattern line having first and second terminals on said substrate, wherein said first terminal is A probe connected directly to the probe, an inductive element connected to the probe, a first lead wire connected to the inductive element, and a second terminal connected to a second lead. A capacitive coupling unit that has a coupling capacitance in a non-contact manner and capacitively couples; a signal input unit that inputs a test signal including an AC component to one of the first lead wire and the second lead wire; A continuity inspection device for a circuit board, comprising: a signal detection unit that detects an output of the inspection signal on one of the first lead wire and the second lead wire. 3. A continuity inspection device for inspecting continuity between said first and second terminals on a substrate provided with a pattern line having first and second terminals on the substrate, wherein said first terminal A first capacitive coupling unit that has a capacitive coupling in a non-contact manner with the first capacitive coupling unit, and is connected to the first capacitive coupling unit so as to form a resonance circuit with the capacitance of the first capacitive coupling unit. An inductive element, a first lead wire connected to the inductive element, and a second lead connected to the second lead and having capacitive coupling to the second terminal in a non-contact manner with a coupling capacitance. A signal input means for inputting a test signal containing an AC component to one of the first lead wire and the second lead wire; and a first lead wire and a second lead wire Signal detection means for detecting the output of the inspection signal. A continuity inspection device for a circuit board. 4. A first terminal group and a second terminal group separated by a predetermined distance.
And a continuity inspection jig provided with a terminal group of the first terminal group, wherein:
A lead wire is connected so that an inspection signal for continuity inspection can be applied, and a contact portion for contacting a substrate to be inspected is provided at each of the first terminal groups or at a part of the second end thereof. One or more inductive elements are connected to each or a part of the second terminal group, and a second end of each or a part of the second terminal group is
A continuity inspection jig provided with electrodes for forming a coupling capacitance in a non-contact manner with the wiring pattern of the substrate to be inspected. 5. The capacitive coupling means is a plate electrode connected to the inductive element, and has a main surface facing the first terminal so as to form a capacitance with the first terminal. The continuity inspection device for a circuit board according to claim 1, further comprising a first flat plate electrode provided. 6. The first capacitive coupling means is a plate electrode connected to the inductive element, and has a main surface formed of the first electrode so as to form a capacitance with the first terminal. 4. The circuit board continuity inspection device according to claim 3, further comprising a first plate electrode provided to face the terminal. 7. The second capacitive coupling means includes: a second plate electrode having a main surface provided to face the second terminal so as to form a capacitance between the second terminal and the second terminal. The circuit board continuity inspection device according to claim 3, comprising: 8. The apparatus according to claim 1, wherein said probe means has a probe connected to said second lead wire and directly detachably connected to said second terminal and detachable. Circuit board continuity inspection device. 9. The probe according to claim 2, wherein said probe means includes a probe connected to said first lead wire, directly connected to said second terminal in a resistive manner, and detachable. Circuit board continuity inspection device. 10. The circuit board continuity inspection apparatus according to claim 1, wherein the inspection signal is an AC signal. 11. The circuit board continuity inspection device according to claim 1, wherein the inspection signal is a pulse signal. 12. A plurality of pattern lines are laid on the substrate, each of the pattern lines has a first terminal group and a second terminal group, and the target terminal is selected from the first terminal group. 4. The circuit board according to claim 1, further comprising a selection unit for selecting a first terminal and connecting the selected first terminal to the inductive element. Continuity inspection device. 13. The circuit board continuity inspection device according to claim 12, wherein said selection means is a multiplexer circuit having a plurality of analog switches. 14. The circuit board continuity inspection apparatus according to claim 13, wherein the multiplexer further includes a switch for grounding an output of a terminal that is not selected. 15. A plurality of pattern lines are laid on the substrate, each of the pattern lines has a first terminal group and a second terminal group, and a target terminal is selected from the second terminal group. 4. The method according to claim 1, further comprising selecting means for selecting a second terminal and connecting the selected second terminal to the second lead wire. Circuit board continuity inspection device. 16. The circuit board continuity inspection apparatus according to claim 15, wherein said selection means is a multiplexer circuit having a plurality of analog switches. 17. The circuit board continuity inspection apparatus according to claim 16, wherein the multiplexer further includes a switch for grounding an output of a terminal that is not selected. 18. A continuity inspection method for inspecting continuity between said first and second terminals of a substrate provided with pattern lines having first and second terminals on the substrate, wherein the first terminal A predetermined capacitance is formed in the vicinity of a predetermined electrode, a predetermined inductive element is connected to the electrode, a first lead wire is connected to the inductive element, and a second lead is connected to the second terminal. Forming a resonance circuit by connecting the first lead wire, the inductive element, the electrode, the coupling capacitor, the first terminal, the pattern wire, the second terminal, and the second lead wire; An application step of applying an inspection signal containing an AC component to one of the first lead wire and the second lead wire; and the other of the first lead wire and the second lead wire, A detection step of detecting an output of the inspection signal. Circuit board continuity inspection method. 19. A continuity inspection method for inspecting continuity between said first and second terminals on a substrate provided with a pattern line having first and second terminals on the substrate, wherein the first terminal By directly contacting the first lead wire via an inductive element and capacitively coupling the second lead wire to the second terminal in a non-contact manner with a coupling capacitance.
Forming a resonance circuit with the first lead wire, the inductive element, the first terminal, the pattern wire, the second terminal, the electrode, the coupling capacitor, and the second lead wire; Applying an inspection signal containing an AC component to one of the first and second lead lines, and detecting the output of the inspection signal at the other of the first and second lead lines. A method for inspecting continuity of a circuit board, comprising a detecting step. 20. A continuity inspection method for inspecting continuity between said first and second terminals on a substrate provided with a pattern line having first and second terminals on the substrate, wherein the first lead wire is provided. The inductive element connected to the first terminal is capacitively coupled to the first terminal via the first electrode in a non-contact manner, and the second lead wire is non-contact with the second terminal via the second electrode. The first lead wire, the inductive element, the first electrode, the coupling capacitance, the first terminal, the pattern line, the second terminal, the second electrode, the coupling capacitance,
A step of forming a resonance circuit with the second lead, an application step of applying an inspection signal containing an AC component to one of the first lead and the second lead, and a step of applying the first lead A continuity inspection method for a circuit board, comprising: a detection step of detecting an output of the inspection signal on one of the wire and the second lead wire. 21. The method according to claim 18, wherein the inspection signal is an AC signal. 22. The continuity inspection method for a circuit board according to claim 18, wherein the inspection signal is a pulse signal. 23. A plurality of pattern lines are laid on the substrate, each of the pattern lines has a first terminal group and a second terminal group, and a desired one of the first terminal groups is provided. 21. The circuit board continuity inspection method according to claim 18, wherein a first terminal is selected, and the selected first terminal is connected to the inductive element. 24. The method further comprising a reference frequency determining step, wherein the reference frequency determining step is performed by changing the frequency of the inspection signal to a predetermined reference substrate while changing the frequency of the test signal before the applying step. A determining step of determining a resonance frequency of a pattern line between a first terminal and a second terminal of the reference substrate, wherein the applying step sets a first lead wire using the resonance frequency as a frequency of an inspection signal. 24. The continuity inspection method for a circuit board according to claim 18, wherein the voltage is applied to one of the first and second lead wires. 25. The method as claimed in claim 25, wherein in the determining step, the frequency of the inspection signal for the reference substrate is varied within a predetermined range centered on a standard frequency previously determined based on the constant of the inductive element. Item 25. The method for inspecting continuity of a circuit board according to any one of Items 18 to 24. 26. The method according to claim 25, wherein in the applying step, the frequency of the inspection signal for the substrate to be inspected is varied within a predetermined range centered on the frequency determined in the determining step. The method for inspecting continuity of a circuit board according to the above. 27. The circuit board continuity inspection apparatus according to claim 1, further comprising means for changing a frequency of the inspection signal. 28. A computer-readable recording medium storing a computer program for implementing the continuity inspection method according to claim 18. 29. A continuity inspection device for inspecting continuity between said first and second terminals of a substrate on which pattern lines having first and second terminals on a substrate are densely provided, wherein said pattern line Between 50 fF and 1 pF
A sensor electrode having a size such that it is within the range of: 20 m
A continuity inspection device comprising: an inductive element having a constant in the range of H to 25 μH; and an oscillator oscillating at a reference frequency falling within a range of 5 MHz to 10 MHz and being changeable within a predetermined range from the reference frequency. .