JP3311698B2 - Circuit board continuity inspection device, continuity inspection method, continuity inspection jig, and recording medium - Google Patents

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.

[0010] To achieve the above object, for example, the first
A continuity inspection device for inspecting continuity between the first terminal and the second terminal on a substrate provided with a pattern having a terminal and a second terminal on the substrate is coupled to the first terminal in a non-contact manner. and capacitive coupling can be capacitive coupling means has a capacity, an inductive element, wherein the capacitive coupling and is connected to said capacitive coupling means in order to form a resonant circuit of the capacitive coupling means, in contact with the second terminal Possible probe means, the inductive element and the capacitance
The capacitive coupling means and the induction may be connected to one of the coupling means.
Input means for inputting a test signal containing an AC component resonating in a resonance circuit formed by the inductive element , and the inductive element
And signal detection means for detecting the output of the test signal from one of the capacitive coupling means .

The mounting position of the inductive element can be variously changed. Alternatively, the continuity inspection device for inspecting continuity between the first terminal and the second terminal on a substrate provided with a pattern having the first terminal and the second terminal on the substrate includes the first terminal directly contactable probe means, said probe means connected inductive elements, and capacitive coupling can be capacitive coupling means includes a coupling capacitor with the second terminal and the non-contact scheme,
Before either the inductive element or the capacitive coupling means
A resonance circuit formed by the capacitive coupling means and the inductive element.
Signal input means for inputting a test signal containing an AC component resonating in a path, and signal detection means for detecting an output of the test signal from one of the inductive element and the capacitive coupling means. And

[0012] A coupling capacitance may be formed at both the first terminal and the second terminal. Furthermore, the continuity inspection device for inspecting the continuity between the first terminal and the second terminal of the substrate provided with the pattern having the first terminal and the second terminal on the substrate includes the first terminal . a first capacitive coupling means capable capacitive coupling has a coupling capacitance with terminal and non-contact manner, connected to said first capacitive coupling means to form a coupling capacitance with the resonant circuit of the first capacitive coupling means Inductive element, second capacitive coupling means capable of capacitively coupling the second terminal with a non-contact type coupling capacitance, and the inductive element and the second capacitive coupling
Said first capacitor to one of means coupling means and a second
The resonance circuit formed by the capacitive coupling means and the inductive element
Signal input means for inputting a test signal containing an AC component resonating in a path, and signal detecting means for detecting an output of the test signal from the other of the inductive element and the second capacitive coupling means. It is characterized by the following.

Further object of the present invention, for example, also by a predetermined distance spaced first terminal group and the second terminal group and is the conductivity test jig provided can be achieved. In this continuity inspection jig, a contact portion is provided at each or a part of the distal end of the first terminal group for contacting the vicinity of one portion of the pattern to be inspected, and each of the second terminal groups is provided with a contact portion. or a portion of one or more inductive element is connected to, wherein the second distal portion of each or some of the group terminals, forming the other portions near the coupling capacitance in a non-contact of the inspection object pattern And an electrode for each of the first terminals is provided.
An inspection signal for continuity inspection is applied to some of the contact portions.
Characterized in that that.

The above object can also be achieved by the following continuity inspection method. That is, a capacitive coupling means capable of capacitively coupling by having a coupling capacitance in a non-contact manner with the first terminal on a substrate provided with a pattern having a first terminal and a second terminal on the substrate; A continuity test for testing the continuity between the first and second terminals, the probe including an inductive element for forming a resonance circuit with the capacitive coupling of the coupling means; and a probe means capable of contacting the second terminal. A method for inspecting continuity in an apparatus, wherein the probe means is brought into contact with the second terminal, a coupling capacitance is formed by bringing the electrode close to the first terminal, and a predetermined inductive element is provided on the electrode. Forming a resonant circuit between the probe means and the inductive element with the coupling capacitance between the first terminal and the electrode and the inductive element; The resonance occurs in one of the elements And applying step of applying a test signal including a resonance frequency component of the road, the pro
And a detecting step of detecting the output of the test signal from one of the inductive element and the other of the inductive elements .

[0015] In order to achieve the same objective,Terminal
And a substrate provided with a pattern having a second terminal on a substrate.
Of the board,An inductive element connectable to the first terminal;
The inductive element having a coupling capacitance in a non-contact manner with a second terminal;
And capacitive coupling means capable of forming a resonance circuit withThe said
Check the continuity between the first and second terminalsIn continuity inspection equipment
ToContinuity inspection methodAndAn inductive element at the first terminal
Contact the saidCapacitive coupling meansNon-contact with the second terminal
By capacitively coupling with a coupling capacitance in the formula,
Inductive elements andThe capacitive coupling meansAnd form a resonant circuit
DoFormationProcess andThe inductive element and the capacitive coupling meansof
Either oneResonance frequency of the resonance circuitInspection containing components
Applying an inspection signal,The inductive element and the container
Quantity coupling meansOutput of the test signal
And a detecting step for detecting a force.Times
Road board continuity inspection method.

To achieve the above object, for example, the first
Capacitive coupling is possible in a non-contact manner with the first terminal of a substrate provided with a pattern having a terminal and a second terminal on the substrate.
First capacitive coupling means comprising a functional first electrode;
A first capacitive coupling means and connected to the inductive element, the second
And a second capacitive element capable of forming a resonance circuit together with the inductive element and the first capacitive coupling means.
And a second capacitive coupling means comprising:
When the <br/> continuity testing method in continuity inspection apparatus for inspecting conduction between the second terminal, the inductive element and the first volume
Through the first electrode amounts coupling means are capacitively coupled with the first terminal and the non-contact method, first of the second capacitive coupling means 2
The inductive element and the first electrode by capacitively coupling to the second terminal in a non-contact manner through the electrode of
And forming a resonant circuit by the coupling capacitance between the coupling capacitor and said second terminal a second electrode between said first terminal, either with the inductive element of the second capacitive coupling means Applying an inspection signal including a resonance frequency component of the resonance circuit to either one of the inductive element and the second
In the other one of the capacitive coupling means, and continuity testing method for the circuit board, characterized by comprising a detection step of detecting an output of the test signal.

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.

[0018] Therefore, in the conductivity test method, for example further, the application step includes a reference frequency determining step, said reference frequency determining step, the frequency of the test signal to be applied with respect to a predetermined reference substrate prior to the detection step the change and determining the resonant frequency.

The frequency change range must be determined in advance. In this reason the reference frequency determining step, characterized that you determine to resonant frequency by varying the frequency in advance within a predetermined range centered on the standard frequency determined based on the constant of the inductive element. 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. To compensate for this error, in the applying step, the group
The frequency of the inspection signal for the substrate to be inspected is varied within a predetermined range around the frequency determined in the quasi-frequency determination step.

[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, 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, when 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 illustrating a system configuration of an apparatus according to an embodiment.

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.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/02 G01R 31/302

Claims (28)

(57) [Claims] A first terminal and a second terminal on a substrate provided with a pattern having the first terminal and the second terminal on the substrate;
A continuity inspection device for inspecting continuity between the terminals, wherein a capacitive coupling unit having a coupling capacitance and capable of capacitive coupling in a non-contact manner with the first terminal is formed; An inductive element connected to the capacitive coupling means, a probe means capable of contacting a second terminal, the capacitive coupling means and the inductive element connected to one of the inductive element and the capacitive coupling means. Signal input means for inputting a test signal including an AC component resonating in a resonance circuit formed by the element, and signal detection means for detecting an output of the test signal from one of the other of the inductive element and the capacitive coupling means A continuity inspection device for a circuit board, comprising: 2. The circuit board continuity inspection device according to claim 1, wherein said probe means includes a removable probe directly connected to said second terminal in a resistive manner. 3. The capacitance coupling means includes a flat plate electrode whose main surface is directed toward the first terminal so as to form a coupling capacitance with the first terminal. The circuit board continuity inspection device according to claim 1 or 2. 4. The first terminal and the second terminal on a substrate provided with a pattern having a first terminal and a second terminal on the substrate.
In a continuity inspection device for inspecting continuity between terminals, a probe means capable of directly contacting the first terminal, an inductive element connected to the probe means, and a non-contact coupling with the second terminal A capacitive coupling unit having a capacitance and capable of capacitive coupling; and an AC component that resonates in a resonance circuit formed by the capacitive coupling unit and the inductive element in one of the inductive element and the capacitive coupling unit. A continuity test for a circuit board, comprising: signal input means for inputting a test signal including the signal; and signal detection means for detecting an output of the test signal from one of the inductive element and the capacitive coupling means. apparatus. 5. The circuit board continuity inspection apparatus according to claim 4, wherein said probe means includes a probe which is directly connected to said second terminal in a resistive manner and is detachable. 6. The capacitive coupling means has a plate electrode whose main surface is provided to face the first terminal so as to form a coupling capacitance with the second terminal. The circuit board continuity inspection device according to claim 4 or 5. 7. The first terminal and the second terminal of a substrate provided with a pattern having a first terminal and a second terminal on the substrate.
A continuity inspection device for inspecting continuity between the terminals, wherein the first terminal has a coupling capacitance in a non-contact manner and has a coupling capacitance and is capable of capacitive coupling; An inductive element connected to the first capacitive coupling means so as to form a resonance circuit with a capacitance; and a second capacitive coupling means capable of capacitively coupling the second terminal with a coupling capacitance in a non-contact manner. And an AC component that resonates in a resonance circuit formed by the first capacitive coupling means, the second capacitive coupling means, and the inductive element in one of the inductive element and the second capacitive coupling means. A signal input means for inputting a test signal including: a signal detecting means for detecting an output of the test signal from one of the other of the inductive element and the second capacitive coupling means. Substrate continuity inspection device. 8. The first capacitive coupling means includes a first plate electrode having a main surface provided to face the first terminal so as to form a coupling capacitance with the first terminal. The circuit board continuity inspection device according to claim 7, comprising: 9. The second capacitive coupling means includes a plate electrode whose main surface is provided to face the second terminal so as to form a coupling capacitance with the second terminal. The continuity inspection device for a circuit board according to claim 7 or 8, wherein: 10. A plurality of patterns are laid on the substrate, each pattern having a first terminal group and a second terminal group, and a target first terminal group is selected from the first terminal group. 10. The circuit board continuity inspection apparatus according to claim 1, further comprising a first selection unit for selecting and connecting the terminal. 11. A plurality of patterns are laid on the substrate, and each pattern line has a first terminal group and a second terminal group, and a desired first terminal group is selected from the second terminal group. 11. The circuit board continuity inspection apparatus according to claim 1, further comprising a second selection unit for selecting and connecting two terminals. 12. The circuit board continuity inspection device according to claim 11, wherein said selection means is a multiplexer circuit having a plurality of analog switches. 13. The circuit board continuity inspection device according to claim 12, wherein the multiplexer further includes a switch for grounding an output of a terminal that is not selected. 14. The continuity inspection device for a circuit board according to claim 1, wherein the inspection signal includes a pulse signal. 15. A continuity inspection jig provided with a first terminal group and a second terminal group separated by a predetermined distance, wherein each of the first terminal group or a part thereof has a tip. Is provided with a contact portion for contacting near one part of the pattern to be inspected, one or more inductive elements are connected to each or a part of the second terminal group, and the second terminal group Each or a part of the tip is provided with an electrode for forming a coupling capacitance in a non-contact manner with the vicinity of the other part of the pattern to be inspected, and the contact of each or a part of the first terminal group is provided. A continuity inspection jig, wherein an inspection signal for continuity inspection is applied to the portion. 16. The circuit board continuity inspection apparatus according to claim 15, wherein the inspection signal is an AC signal that resonates in a resonance circuit formed by the capacitive coupling unit and the inductive element. 17. The apparatus according to claim 1, further comprising a determination unit for determining a resonance frequency of the inspection target.
The circuit board continuity inspection device according to any one of the above. 18. A continuity inspection device for inspecting continuity between a first terminal and a second terminal of a substrate on which a pattern having a first terminal and a second terminal is densely provided, wherein: A sensor electrode having a coupling capacitance between the pattern positioned at the opposing position and a range of 50 fF to 1 pF; and 20 m connected in parallel or in series with the sensor electrode.
An inductive element having a constant in a range of H to 25 μH, and an oscillator oscillating at a frequency falling within a range of 5 MHz to 10 MHz and capable of changing an oscillation frequency output within the oscillation frequency range. Is a continuity inspection device that oscillates and outputs at a frequency that resonates with a resonance circuit formed by the capacitive coupling between the sensor electrode and the pattern and the inductive element. 19. A capacitive coupling means having a coupling capacitance in a non-contact manner with the first terminal on a substrate provided with a pattern having a first terminal and a second terminal on the substrate. An inductive element for forming a resonance circuit with the capacitive coupling of the capacitive coupling means, and probe means capable of contacting the second terminal, and inspecting continuity between the first and second terminals. A continuity inspection method in a continuity inspection device, wherein the probe means is brought into contact with the second terminal, the electrode is brought close to the first terminal to form a coupling capacitance, and a predetermined induction is applied to the electrode. Forming a resonance circuit between the probe means and the inductive element with a coupling capacitance between the first terminal and the electrode by connecting the inductive element and the inductive element; and Any one of the inductive elements An application step of applying a test signal including a resonance frequency component of the resonance circuit; and a detection step of detecting an output of the test signal from the other of the probe unit and the inductive element. Circuit board continuity inspection method. 20. An inductive element connectable to the first terminal on a substrate provided with a pattern having a first terminal and a second terminal on the substrate, wherein the inductive element is in non-contact with the second terminal. A continuity inspection method for a continuity inspection device for inspecting continuity between the first and second terminals, comprising: a capacitance coupling unit having a coupling capacitance and capable of forming a resonance circuit with the inductive element; The first terminal is brought into contact with an inductive element, and the capacitive coupling means is capacitively coupled to the second terminal in a non-contact manner with a coupling capacitance, whereby resonance occurs between the inductive element and the capacitive coupling means. Forming a circuit; applying an inspection signal including a resonance frequency component of the resonance circuit to one of the inductive element and the capacitive coupling unit; In either case, the detection A detection step of detecting an output of a test signal. 21. A first substrate provided with a pattern having a first terminal and a second terminal on a substrate, the first electrode including a first electrode capable of capacitively coupling to the first terminal in a non-contact manner. A capacitive coupling means, an inductive element connected to the first capacitive coupling means, and a non-contact coupling capacitance with the second terminal to form a resonance circuit together with the inductive element and the first capacitive coupling means. A continuity test method in a continuity test device for testing continuity between the first and second terminals, comprising: a second capacitive coupling unit having a second electrode that can be formed; Capacitively coupled to the first terminal via the first electrode of the capacitive coupling means in a non-contact manner;
The second capacitive coupling means via the second electrode;
And the coupling capacitance between the inductive element, the first electrode, and the first terminal, and the coupling capacitance between the second terminal and the second electrode. Forming a resonance circuit by: applying an inspection signal including a resonance frequency component of the resonance circuit to one of the inductive element and the second capacitive coupling unit; A detection step of detecting the output of the test signal in one of the second capacitive coupling means. 22. The continuity inspection method for a circuit board according to claim 19, wherein the inspection signal is an AC signal. 23. The method according to claim 19, wherein the inspection signal is a pulse signal. 24. A plurality of patterns are laid on the substrate, each pattern having a first terminal group and a second terminal group, and a target first terminal group is selected from the first terminal group. 21. The terminal according to claim 19, wherein said terminal is selected and connected.
3. The method for inspecting continuity of a circuit board according to any one of 3. 25. The application step includes a reference frequency determination step, wherein the reference frequency determination step determines a resonance frequency by changing a frequency of an inspection signal applied to a predetermined reference substrate prior to the detection step. The method for inspecting continuity of a circuit board according to any one of claims 19 to 24, wherein: 26. In the reference frequency determining step,
26. The continuity inspection method for a circuit board according to claim 25, wherein the resonance frequency is determined by varying the frequency within a predetermined range around a standard frequency determined in advance based on the constant of the inductive element. . 27. The method according to claim 27, 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 reference frequency determining step. 27. The circuit board continuity inspection method according to 26. 28. A computer readable recording medium for recording a computer program for realizing the steps according to claim 19 to claim 21 or claim 24 to claim 27.