JP7049975B2 - Wiring board and wiring board inspection method - Google Patents

Description

The present disclosure relates to a wiring board and a method for inspecting a wiring board.

Currently, high-performance package boards and wiring boards for mounting electronic components are being developed. The wiring board has a plurality of insulating layers, mounting electrodes, and wiring conductors laminated with each other. Wiring conductors include signal conductors and grounding conductors. These wiring conductors are located between layers of laminated insulating layers. The mounting electrode and the wiring conductor, or the wiring conductors in different layers, are electrically connected by a through-hole conductor in a through-hole penetrating the insulating layer in the thickness direction. Such a wiring board is mounted on an electronic device such as a server.

Japanese Unexamined Patent Publication No. 2015-99854

In recent years, along with the sophistication of electronic devices, the sophistication of package substrates and electronic components has progressed, and high-frequency signals capable of transmitting a large amount of information at high speed may be used. In order to transmit a high frequency signal with high accuracy, the signal path of the wiring board is required to reduce the number of conductors protruding in a branch shape in the path, that is, the conductor having an open end. Therefore, even in the vicinity of the connection portion between the signal conductor and the through-hole conductor, the through-hole conductor located below the connection portion is removed by a drill or the like. However, since it is difficult to accurately inspect the removal condition of the through-hole conductor, the through-hole conductor may remain below the connection portion and the transmission characteristics of the high-frequency signal may be deteriorated.

The wiring substrate of the present disclosure penetrates a plurality of insulating layers laminated to each other, a first region located on the upper surface of the uppermost insulating layer, and a plurality of insulating layers in the thickness direction in the first region. The signal through hole, the ground through hole that penetrates a plurality of insulating layers in the thickness direction in the first region, the signal through hole conductor located in the signal through hole, and the ground. A grounding through-hole conductor located in a through-hole for a signal, a signal conductor located between at least one layer of a plurality of insulating layers and connected to a through-hole conductor for a signal, and a plurality of insulating layers. In the inspection, the conductor pattern is located between the layers below the layer where the signal conductor is located, and a part of the conductor is exposed in the signal through hole, and the first region has a predetermined wavelength. It has a first electrode and a second electrode to which a voltage can be applied, the first electrode is electrically connected to the signal through-hole conductor, and the second electrode is electrically connected to the ground through-hole conductor. It has a first mounting electrode that is connected, the conductor pattern is insulated from other conductors, and the lower end of the signal through-hole conductor is the signal conductor and conductor in the thickness direction. It is characterized by being located between the pattern.

The method for inspecting the wiring board of the present disclosure includes a step of preparing a wiring board having the above configuration, a step of preparing an inspection device having a plurality of terminals including a first terminal and a second terminal, and a first electrode of the first terminal. A step of contacting the second terminal with the second electrode and a step of applying an inspection voltage having a predetermined wavelength to the first electrode and the second electrode while maintaining the contact step. It includes a step of measuring the reflection characteristic of the signal conductor when an inspection voltage is applied and a step of determining the insulation state between the signal conductor and the conductor pattern based on the result of the reflection characteristic. It is a feature.

According to the configuration of the present disclosure, it is possible to provide a wiring board having excellent transmission characteristics of a high frequency signal.

According to the inspection method of the present disclosure, it becomes possible to easily inspect the insulation state between the signal conductor and the conductor pattern.

FIG. 1 is a schematic perspective view showing an example of an embodiment of the wiring board of the present disclosure. FIG. 2 is a plan perspective view showing a main part of an embodiment of the wiring board of the present disclosure. FIG. 3 is a schematic cross-sectional view showing a main part of an embodiment of the wiring board of the present disclosure. FIG. 4 is a diagram showing a state of reflection characteristics in the embodiment of the wiring board of the present disclosure. FIG. 5 is a plan perspective view showing a main part of another embodiment of the wiring board of the present disclosure. FIG. 6 is a schematic cross-sectional view showing an example in the case where the processing of the wiring board fails. FIG. 7 is a schematic perspective view showing another embodiment of the wiring board of the present disclosure. FIG. 8 is a diagram showing a state of passage characteristics in the embodiment of the wiring board of the present disclosure. FIG. 9 is a plan perspective view showing a main part of another embodiment of the wiring board of the present disclosure. FIG. 10 is a schematic cross-sectional view showing an example of an embodiment of the inspection method of the wiring board of the present disclosure. FIG. 11 is a schematic cross-sectional view showing an embodiment of another inspection method for the wiring board of the present disclosure.

Next, the wiring board of the present disclosure will be described with reference to FIGS. 1 to 4. The wiring board 1 has an insulating substrate 2, a wiring conductor 3, a first mounting electrode 4, and a solder resist 5. The wiring board 1 has a first region 6 on the upper surface on which, for example, a package board, an electronic component, or the like is mounted. The wiring board 1 has a thickness of about 0.04 to 10.0 mm.

The insulating substrate 2 has five insulating layers 7 laminated to each other. The insulating layer 7 contains, for example, an insulating material obtained by impregnating a reinforcing glass cloth with an epoxy resin, a bismaleimide triazine resin, or the like. The insulating substrate 2 has a function of securing an arrangement area of the wiring conductor 3 in the wiring board 1, a function as a support for maintaining flatness, and the like. The thickness of each insulating layer 7 is set to, for example, 20 to 400 μm.

The insulating substrate 2 has a plurality of through holes 8 penetrating in the thickness direction thereof. The through hole 8 includes a signal through hole 8S and a grounding through hole 8G. The signal through hole 8S has a diameter-expanded portion 8w whose diameter increases below the insulating substrate 2. The wiring conductors 3 located between the first mounting electrode 4 located on the upper surface of the insulating substrate 2 and the plurality of insulating layers 7 or the wiring conductors 3 located between different layers are through holes 8. It is electrically connected via. The diameter of the through hole 8 is set to, for example, 50 to 600 μm.

The wiring conductor 3 includes layers of the plurality of insulating layers 7, upper and lower surfaces of the insulating substrate 2, and through holes 8.
Located inside. The wiring conductor 3 constitutes a signal transmission path and a power supply path in the wiring board 1. The wiring conductor 3 has a signal conductor 3S used for signal transmission and a grounding conductor 3G for providing a potential difference in a power supply path. The wiring conductor 3 contains a good conductive metal such as copper.

Among such wiring conductors 3, those located in the through-hole 8 function as the through-hole conductor 9. The wiring conductor 3 in the signal through-hole 8S functions as a signal through-hole conductor 9S. The wiring conductor 3 in the grounding through-hole 8G functions as a grounding through-hole conductor 9G.

The signal conductor 3S and the signal through-hole conductor 9S are electrically connected. The grounding conductor 3G and the grounding through-hole conductor 9G are electrically connected.

The first mounting electrode 4 is located in the first region 6 and has a first electrode 4a and a second electrode 4b. The first electrode 4a is connected to the signal conductor 3S via the signal through-hole conductor 9S. The second electrode 4b is connected to the grounding conductor 3G via the grounding through-hole conductor 9G. The first electrode 4a and the second electrode 4b are for confirming that the lower end portion of the signal through-hole conductor 9S is cut off so as to be located between the signal conductor 3S and the conductor pattern 10. It is possible to apply an inspection voltage.

The inspection voltage is an AC voltage having a predetermined wavelength. As the AC voltage, for example, one having a frequency in the range of about 1 to 100 GHz is used, and a frequency of about 5 GHz is practically used.

A conductor pattern 10 that is insulated from other conductors is located between layers one layer below the layer on which the signal conductor 3S is located. As shown in FIG. 2, a part of the conductor pattern 10 is exposed in the enlarged diameter portion 8w in the signal through hole 8S. That is, the conductor pattern 10 has, for example, a linear structure having two ends, and one end is exposed in the enlarged diameter portion 8w in the signal through hole 8S.

In such a state, when the inspection voltage is applied to the first mounting electrode 4 and the reflection characteristics in the signal conductor 3S are measured, the lower end of the signal through-hole conductor 9S is the signal conductor 3S and the conductor pattern 10. When it is cut and removed so as to be located between and, a waveform as shown in A of FIG. 4 is shown. On the other hand, when the signal through-hole conductor 9S cannot be completely cut and is in a conductive state with the conductor pattern 10, a waveform as shown in B of FIG. 4 is shown. That is, it is possible to measure waveforms having different shapes depending on whether the signal through-hole conductor 9S and the conductor pattern 10 are in a non-conducting state and in a conducting state.

In other words, it is simply detected that the conductor pattern 10 having an open end and projecting in a branch shape exists in the transmission path of the signal including the signal conductor 3S and the signal through-hole conductor 9S in a conductive state. Will be possible.

As shown in FIGS. 2 and 3, the length L1 of the conductor pattern 10 and the shortest length L2 between the openings of the conductor pattern 10 and the signal through hole 8S in the first region 6 in plan perspective and the signal. The sum of the length L3 in the thickness direction between the conductor 3S and the conductor pattern 10 may be an odd multiple of 1/4 of the wavelength of the inspection voltage.

In such a case, the difference in the waveform showing the reflection characteristic of the signal conductor 3S is remarkably different between the case where the signal through-hole conductor 9S and the conductor pattern 10 are in the non-conducting state and the case where they are in the conducting state. Therefore, it is advantageous in that it becomes easy to judge the continuity status of both.

Such a wiring board 1 can be formed, for example, as follows. First, prepare two double-sided copper-clad laminates. The double-sided copper-clad laminate is, for example, one in which a copper foil is attached to the upper and lower surfaces of an insulating plate in which a glass cloth is impregnated with an insulating resin. Next, the copper foil of each double-sided copper-clad laminate is processed into a predetermined pattern by etching to form a wiring conductor 3 including a signal conductor 3S and a grounding conductor 3G, and a conductor pattern 10. At this time, the signal conductor 3S and the conductor pattern 10 are formed on different surfaces of the double-sided copper-clad laminate. Next, prepare three prepregs and two copper foils. The prepreg is, for example, a semi-cured insulating material in which a glass cloth is impregnated with an insulating resin. Next, with one prepreg as the center, double-sided copper-clad laminates, prepregs, and copper foils are laminated in this order on the upper and lower surfaces thereof. Next, the insulating substrate 2 as described above is formed by performing press working under heating.

Next, a through hole penetrating the insulating substrate 2 in the thickness direction is formed by drilling. A part of the signal conductor 3S and a part of the conductor pattern 10 are exposed in the through hole which becomes the signal through hole 8S by drilling. A part of the grounding conductor 3G is exposed in the through hole that becomes the grounding through hole 8G. Next, the resin dust remaining in the through hole is removed by desmear treatment. Finally, the through hole 8 as described above is formed by etching the wiring conductor 3 exposed in the through hole 8.

It should be noted that this etching treatment also has an effect of removing metal debris that cannot be completely removed by the desmear treatment and resin debris stuck to the side surface of the wiring conductor 3 exposed in the through hole.

Next, the electroless copper plating treatment and the electrolytic copper plating treatment are sequentially performed on the upper and lower surfaces of the insulating substrate 2 and in the through holes 8. As a result, the first mounting electrode 4 and the through-hole conductor 9 are formed at the same time. The signal through-hole conductor 9S is connected to a part of the signal conductor 3S exposed in the signal through hole 8S and a part of the conductor pattern 10. The grounding through-hole conductor 9G is connected to a part of the grounding conductor 3G exposed in the grounding through hole 8G.

Next, the signal through-hole conductor 9S is cut and removed from the lower surface side of the insulating substrate 2 to the lower side of the signal conductor 3S. By this cutting process, the lower end portion of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the enlarged diameter portion 8w is formed.

For cutting, for example, a drill having a diameter larger than the diameter of the signal through hole 8S may be used. By this cutting process, the signal through-hole conductor 9S and the conductor pattern 10 are separated. As a result, the conductor pattern 10 is in an insulated state from other conductors.

Finally, the solder resist 5 is formed on the upper surface of the uppermost insulating layer 7 and the lower surface of the lowermost insulating layer 7. The solder resist 5 is formed by attaching a film of a photosensitive thermosetting resin such as an acrylic modified epoxy resin to the surface of the insulating layer 7 and forming openings 5a or 5b by exposure and development to perform thermosetting. Is formed by. As a result, the wiring board 1 as shown in FIG. 1 is formed.

As described above, the wiring board 1 of the present disclosure includes a signal through hole 8S and a grounding through hole 8G that penetrate a plurality of insulating layers 7 in the thickness direction, a signal through hole conductor 9S, and a grounding through. The hole conductor 9G, the signal conductor 3S connected to the signal through-hole conductor 9S, the conductor pattern 10 located between the layers below the layer where the signal conductor 3S is located, and the first conductor pattern 10. The electrode 4a has a first mounting electrode 4 that is electrically connected to the signal through-hole conductor 9S and the second electrode 4b is electrically connected to the grounding through-hole conductor 9G. The conductor pattern 10 is insulated from other conductors, and the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10 in the thickness direction.

Therefore, when the inspection voltage is applied to the first mounting electrode 4 and the reflection characteristics of the signal conductor 3S are measured, the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10. It is possible to measure waveforms having different shapes depending on whether the signal is cut and removed so as to be positioned and the signal through-hole conductor 9S cannot be completely cut and is in a conductive state with the conductor pattern 10.

That is, in the signal transmission path including the signal conductor 3S and the signal through-hole conductor 9S, the conductor pattern 10 having an open end and projecting in a branch shape exists in a conductive state with the signal through-hole conductor 9S. Can be easily detected.

As a result, according to the configuration of the present disclosure, it is possible to prevent a conductor pattern having an open end and projecting in a branch shape from being mixed in the signal transmission path, and the wiring has excellent high-frequency signal transmission characteristics. A substrate can be provided.

The present disclosure is not limited to the above-mentioned example of the embodiment, and various changes can be made as long as it does not deviate from the gist of the present disclosure.

For example, in one example of the above-described embodiment, as shown in FIG. 2, a case where one conductor pattern 10 is located around the enlarged diameter portion 8w in one signal through hole 8S is shown.

Apart from this case, as shown in FIG. 5, a plurality of conductor patterns 10 may be located around the enlarged diameter portion 8w of the signal through hole 8S in the same layer. In FIG. 5, four conductor patterns 10 are located around the enlarged diameter portion 8w. One end of each conductor pattern 10 is exposed at equal intervals along the inner circumference of the enlarged diameter portion 8w.

When there is only one conductor pattern 10, as shown in FIG. 6, for example, in the above-mentioned cutting step, the insertion position of the drill is displaced and the signal through-hole conductor 9S is not completely removed by cutting. When the signal through-hole conductor 9S and the conductor pattern 10 are separated, there is a possibility that the uncut portion of the signal through-hole conductor 9S cannot be detected by measuring the reflection characteristics.

However, when a plurality of conductor patterns 10 are arranged as described above, one of the conductor patterns 10 is in a conductive state with the signal through-hole conductor 9S even when the insertion position of the drill is displaced. Therefore, it is possible to detect the uncut portion of the signal through-hole conductor 9S by measuring the reflection characteristic.

Further, as shown in FIG. 7, the wiring board 1 may have the second region 11 at a position different from that of the first region 6 described above. The second region 11 has a second mounting electrode 12 having a third electrode 12a electrically connected to the first electrode 4a and a fourth electrode 12b electrically connected to the second electrode 4b. are doing. For example, a package substrate, an electronic component, or the like is mounted on the second region 11, and the package substrate, the electronic component, or the like mounted on the first region 6 is electrically connected to each other.

In such a case, it becomes possible to mount a plurality of package boards, electronic components, and the like, which is advantageous for enhancing the functionality of electronic devices.

When the wiring board 1 has a first mounting electrode 4 and a second mounting electrode 12 that are electrically connected to each other, the first electrode 4a, the third electrode 12a, and the second electrode 12a are provided. By simultaneously applying the above inspection voltage to the electrode 4b and the fourth electrode 12b and measuring the passing characteristics, the lower end portion of the signal through-hole conductor 9S is placed between the signal conductor 3S and the conductor pattern 10. It is also possible to inspect whether or not the conductor 9S for signal and the conductor pattern 10 are separated from each other.

When the above inspection voltage is applied to the first mounting electrode 4 and the second mounting electrode 12 and the passing characteristics of the signal conductor 3S are measured, the lower end of the signal through-hole conductor 9S is the signal conductor 3S and the conductor pattern. When it is cut and removed so as to be located between 10 and the through-hole conductor 9S for signal and the conductor pattern 10 are separated, a waveform as shown in A of FIG. 8 is shown. On the other hand, when the signal through-hole conductor 9S cannot be completely cut and is in a conductive state with the conductor pattern 10, a waveform as shown in FIG. 8B is shown.

That is, it is possible to measure waveforms having different shapes depending on whether the signal through-hole conductor 9S and the conductor pattern 10 are in a non-conducting state and in a conducting state. By comparing this, the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal through-hole conductor 9S and the conductor pattern 10 are separated. It is possible to inspect whether or not it is.

Further, in one example of the above-described embodiment, the case where the single or plurality of conductor patterns 10 are individually positioned corresponding to one signal through hole 8S is shown.

Apart from this case, for example, as shown in FIG. 9, when the signal through holes 8S are located adjacent to each other, one conductor pattern 10 is adjacent to each other (two in this example). ) May be located in a state corresponding to the signal through hole 8S. In other words, the conductor pattern 10 has a continuous structure and is located in a state where a part of the conductor pattern 10 is exposed on the inner circumference of the enlarged diameter portion 8w.

As described above, when the plurality of signal through-holes 8S have a common conductor pattern 10, the number of conductor patterns 10 can be reduced, so that the arrangement area of the conductor pattern 10 is reduced. Therefore, it is advantageous from the viewpoint of miniaturization of the wiring board.

Further, in one example of the above-described embodiment, the case where the through-hole conductor 9 is filled in the through-hole 8 is shown. Apart from this case, the through-hole conductor 9 may have a tubular shape that is in close contact with the side surface of the insulating layer 7 exposed in the through-hole 8 and the side surface of the wiring conductor 3. In other words, the through-hole conductor 9 is located in close contact with the entire side surface of the wiring conductor 3 exposed in the through hole 8 and the side surface of the insulating layer 7, and is a radial center portion of the through hole 8. It has a shape with a cavity in.

In such a case, the plating processing time for forming the through-hole conductor 9 can be shortened, which is advantageous from the viewpoint of improving productivity. Further, in such a case, since the first mounting electrode 4 and the second mounting electrode 12 cannot be formed directly above the through hole 8, they may be provided in a region close to the opening of the through hole 8.

Next, based on FIG. 10, in the wiring board 1 of the present disclosure, an inspection for confirming that the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10. An embodiment of the method will be described. The detailed description of the wiring board 1 described above will be omitted.

First, the inspection device 13 having the wiring board 1 and the first terminal 14 and the second terminal 15 described above.
Prepare. An example of the inspection device 13 is a network analyzer.

Next, the first terminal 14 is brought into contact with the first electrode 4a, and the second terminal 15 is brought into contact with the second electrode 4b.

Next, while maintaining the contacting step, an inspection voltage having a predetermined wavelength is applied to the first electrode 4a and the second electrode 4b. The inspection voltage is an AC voltage having a predetermined wavelength. As the AC voltage, for example, a frequency of about 1 to 100 GHz is used, and a frequency of about 5 GHz is practically used.

Next, the reflection characteristics of the signal conductor 3S when the inspection voltage is applied are measured. By this measurement, a waveform showing the state of the reflection characteristic is recorded.

Finally, when the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal through-hole conductor 9S and the conductor pattern 10 are in a non-conducting state. The waveform showing the state of the reflection characteristics is compared with the waveform recorded by the measurement.

In the above-mentioned wiring board 1, when the relative dielectric constant ε = 4 of the insulating layer 7 and the frequency f = 5 GHz of the inspection voltage, the lower end of the signal through-hole conductor 9S is the signal conductor 3S and the conductor pattern 10. The waveform showing the state of the reflection characteristic when the signal through-hole conductor 9S and the conductor pattern 10 are in a non-conducting state is located between the two, and shows a shape as shown in FIG. 4A, for example.

On the other hand, the waveform showing the state of the reflection characteristic when the signal through-hole conductor 9S and the conductor pattern 10 are in a conductive state shows a shape as shown in FIG. 4B, for example. By comparing which waveform the waveform recorded by the measurement corresponds to, the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal is signaled. It can be confirmed whether or not the through-hole conductor 9S and the conductor pattern 10 are separated.

As described above, according to the inspection method of the present disclosure, the lower end portion of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal through-hole conductor 9S and the conductor. It can be easily confirmed whether or not the pattern 10 is separated from the pattern 10.

As a result, it becomes possible to prevent a conductor pattern having an open end and projecting in a branch shape from being mixed in the signal transmission path, and it is possible to provide a wiring board having excellent high-frequency signal transmission characteristics.

Next, based on FIG. 11, in the wiring substrate 1 of the present disclosure, the lower end portion of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal through hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10. An embodiment of another inspection method for confirming that the hole conductor 9S and the conductor pattern 10 are separated will be described. The detailed description of the wiring board 1 described above will be omitted.

First, a wiring board 1 having a first region 6 and a second region 11 and an inspection device 16 having a first terminal 14, a second terminal 15, a third terminal 17, and a fourth terminal 18 are prepared. The first electrode 4a and the second electrode 4b are located in the first region 6. The third electrode 12a and the fourth electrode 12b are located in the second region 11. The inspection device 16 includes a network analyzer.

Next, the first terminal 14 is brought into contact with the first electrode 4a, the second terminal 15 is brought into contact with the second electrode 4b, and the second terminal 15 is brought into contact with the second electrode 4b.
The third terminal 17 abuts on the third electrode 12a, and the fourth terminal 18 abuts on the fourth electrode 12b.

Next, while maintaining the contacting step, an inspection voltage having a predetermined wavelength is applied to the first electrode 4a to the fourth electrode 12b. The inspection voltage is an AC voltage having a predetermined wavelength. As the AC voltage, for example, a frequency of about 1 to 100 GHz is used, and a frequency of about 5 GHz is practically used.

Next, at least one of the pass characteristic and the reflection characteristic in the signal conductor 3S when the inspection voltage is applied is measured. By this measurement, at least one of the waveform indicating the state of the passage characteristic and the waveform indicating the state of the reflection characteristic is recorded. In practice, by applying the inspection voltage, the pass characteristics and the reflection characteristics are measured at the same time, and both characteristics are recorded.

Finally, the waveform showing the passage characteristics when the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10 is compared with the waveform of the passage characteristics recorded by the measurement. do. Alternatively, the waveform showing the reflection characteristics when the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10 is compared with the waveform of the reflection characteristics recorded by the measurement. ..

In the above-mentioned wiring board 1, when the relative dielectric constant ε = 4 of the insulating layer 7 and the frequency f = 5 GHz of the inspection voltage, the lower end of the signal through-hole conductor 9S is the signal conductor 3S and the conductor pattern 10. The waveform showing the passage characteristic when the through-hole conductor 9S for signal and the conductor pattern 10 are separated from each other is located between the two, and shows a shape as shown in FIG. 8A, for example.

On the other hand, the waveform showing the state of the passing characteristic when the signal through-hole conductor 9S and the conductor pattern 10 are in a conductive state shows a shape as shown in FIG. 8B, for example. By comparing which waveform the waveform recorded by the measurement corresponds to, the lower end of the signal through-hole conductor 9S is located between the signal conductor 3S and the conductor pattern 10, and the signal is signaled. It can be confirmed whether or not the through-hole conductor 9S and the conductor pattern 10 are separated.

According to the measurement results of only the passing characteristics, it can be confirmed that the signal through-hole conductor 9S and the conductor pattern 10 are in a conductive state, but whether they are in a conductive state in the first region 6 or the second region. It is not possible to determine whether it is the conduction state in 11. Therefore, the above judgment can be made by utilizing the measurement results of the reflection characteristics together.

1 Wiring board 3S Signal conductor 4 1st mounting electrode 4a 1st electrode 4b 2nd electrode 6 1st area 7 Insulation layer 8G Grounding through hole 8S Signal through hole 9G Grounding through hole conductor 9S Signal through hole conductor 10 Conductor pattern 11 2nd region 12 2nd mounting electrode 12a 3rd electrode 12b 4th electrode 13 and 16 Inspection equipment 14 1st terminal 15 2nd terminal 17 3rd terminal 18 4th terminal

Claims (6)

With multiple insulating layers stacked on top of each other,
The first region located on the upper surface of the insulating layer of the uppermost layer and
In the first region, a signal through hole penetrating the plurality of insulating layers in the thickness direction,
In the first region, a grounding through hole penetrating the plurality of insulating layers in the thickness direction and
The signal through-hole conductor located in the signal through-hole,
The grounding through-hole conductor located in the grounding through-hole,
A signal conductor located between at least one layer of the plurality of insulating layers and connected to the signal through-hole conductor.
In the plurality of insulating layers, a conductor pattern located between layers below the layer in which the signal conductor is located, and a part of which is exposed in the signal through hole,
The first region has a first electrode and a second electrode capable of applying an inspection voltage having a predetermined wavelength, and the first electrode is electrically connected to the signal through-hole conductor and The second electrode has a first mounting electrode that is electrically connected to the grounding through-hole conductor.
The conductor pattern is insulated from other conductors, and the lower end of the signal through-hole conductor is located between the signal conductor and the conductor pattern in the thickness direction. Wiring board. The length of the conductor pattern, the shortest length between the conductor pattern and the opening of the signal through hole in the first region in plan perspective, and the length in the thickness direction between the signal conductor and the conductor pattern. The wiring board according to claim 1, wherein the total of the above is an odd multiple of 1/4 of the wavelength of the inspection voltage. The wiring board according to claim 1 or 2, wherein a plurality of conductor patterns are located in the same layer. The upper surface of the insulating layer on the uppermost layer has a second region at a position different from that of the first region, and the second region includes a third electrode electrically connected to the first electrode and a third electrode. The wiring substrate according to any one of claims 1 to 3, wherein the wiring substrate has a second mounting electrode having the second electrode and the fourth electrode electrically connected to the second electrode. The step of preparing the wiring board according to any one of claims 1 to 4.
The process of preparing an inspection device having a plurality of terminals including the first terminal and the second terminal, and
A contact step in which the first terminal is brought into contact with the first electrode and the second terminal is brought into contact with the second electrode.
A step of applying an inspection voltage having a predetermined wavelength to the first electrode and the second electrode while maintaining the contact step, and a step of applying the inspection voltage to the first electrode and the second electrode.
The step of measuring the reflection characteristics of the signal conductor when the inspection voltage is applied, and
A method for inspecting a wiring board, comprising a step of determining an insulating state between the signal conductor and the conductor pattern based on the measurement result of the reflection characteristic . The process of preparing the wiring board according to claim 4 and
The process of preparing an inspection device having a plurality of terminals including the first terminal to the fourth terminal, and
The first terminal is in contact with the first electrode, the second terminal is in contact with the second electrode, the third terminal is in contact with the third electrode, and the fourth terminal is in contact with the fourth electrode. The contact process and the contact process
A step of applying an inspection voltage having a predetermined wavelength to the first electrode to the fourth electrode while maintaining the contact step, and a step of applying the inspection voltage to the first electrode to the fourth electrode.
A step of measuring at least one of the pass characteristics and the reflection characteristics of the signal conductor when the inspection voltage is applied, and
A method for inspecting a wiring board, comprising a step of determining an insulation state between the signal conductor and the conductor pattern based on the measurement results of at least one of the passage characteristic and the reflection characteristic .

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