JPH10270816A - Printed wiring board - Google Patents

Abstract

(57) [Problem] To provide a printed wiring board for an electromagnetic wave interference countermeasure which is effective for a magnetic field by using a binder in which magnetic particles and inorganic particles are dispersed as an electric insulating layer, so that the multilayer substrate has less warpage. provide. SOLUTION: BaFe ₁₂ O ₁₉ , SrFe ₁₂ O ₁₉ or the like is used as plate-like magnetic particles used in an electric insulating layer, and α-Fe ₂ O ₃ , mica, graphite or the like is used as plate-like non-magnetic inorganic particles. Used. The mixing ratio of the plate-shaped magnetic particles 2 and the plate-shaped non-magnetic inorganic particles 3 to the binder 1 in the electric insulating layer is preferably 50:50 to 20:80 by weight. A binder resin is used as a binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board for preventing electromagnetic wave interference which is effective for a magnetic field without warping of a substrate after manufacturing a multilayer substrate.

[0002]

2. Description of the Related Art With the rapid development of the information society, recent electronic devices typified by mobile phones and PHSs have been developed in the direction of miniaturization and weight reduction in addition to multifunctionality. In order to develop electronic devices in the direction of miniaturization and weight reduction, it is important to increase the density of the wiring pattern of the printed wiring board and increase the thickness of the printed wiring board while reducing the thickness. In order to reduce the thickness of the printed wiring board and increase the number of layers, it is necessary to reduce the thickness of each core material and prepreg. Is thin. Therefore, the printed wiring board is a step of heating the printed wiring board such as a printing and drying process of a solder resist ink, a washing process, a heating process before punching, and the like,
Warpage tends to occur when passing through the soldering process.

When a current flows through a circuit of a printed wiring board, a magnetic field is generated in the wiring of the circuit, and an electromagnetic wave is generated by the magnetic field. Since both the magnetic field and the electromagnetic wave affect between the devices, they are sources of noise.

[0004]

In order to develop electronic devices in the direction of miniaturization and weight reduction, it is important to increase the density of the wiring pattern of the printed wiring board and to increase the number of layers while reducing the thickness. is there. In order to increase the thickness of the printed wiring board while reducing the thickness, it is necessary to reduce the thickness of each core material and prepreg. For this reason, there is a problem that the warpage easily occurs after the printed wiring board manufacturing process is completed.

When a current flows through a circuit of a printed wiring board, a magnetic field is generated in the wiring of the circuit, and an electromagnetic wave is generated by the magnetic field. Since both the magnetic field and the electromagnetic wave affect between the devices, there is a problem that the noise and the electromagnetic wave are sources of noise.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed wiring board for preventing electromagnetic waves which is effective against a magnetic field without warping of a substrate after manufacturing a multi-layer substrate. .

[0007]

In order to achieve the above object, a first printed wiring board of the present invention comprises an electric insulating layer using a binder in which plate-like magnetic particles and plate-like non-magnetic inorganic particles are dispersed. And applying the electric insulating layer to both sides of the printed wiring board.

In the above structure, the mixing ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and The mixing ratio with respect to the plate-like non-magnetic inorganic particles is preferably from 70:30 to 30:70 by weight.

Next, the second printed wiring board of the present invention forms an electric insulating layer using a binder in which plate-shaped magnetic particles and needle-shaped non-magnetic inorganic particles are dispersed, and the electric insulating layer is printed wiring. It is applied to both sides of the board, and the respective electric insulating layers are applied while being shifted in the direction of 90 degrees.

In the above structure, the mixing ratio of the plate-like magnetic particles and the needle-like non-magnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and It is preferable that the compounding ratio with respect to the acicular non-magnetic inorganic particles is 70:30 to 30:70 by weight.

Next, the third printed wiring board of the present invention forms an electric insulating layer using a binder in which needle-like magnetic particles and plate-like non-magnetic inorganic particles are dispersed, and the electric insulating layer is printed wiring. It is applied to both sides of the plate, and the respective electric insulating layers are applied while being shifted and oriented in a direction of 90 degrees.

In the above construction, the mixing ratio of the acicular magnetic particles and the plate-like non-magnetic inorganic particles to the binder in the electric insulating layer is 50:50 to 20:80 by weight, and The mixing ratio with respect to the plate-like non-magnetic inorganic particles is preferably from 70:30 to 30:70 by weight.

Next, a fourth printed wiring board according to the present invention forms an electrical insulating layer using a binder in which needle-like magnetic particles and needle-like non-magnetic inorganic particles are dispersed, and the electrical insulating layer is printed wiring. It is applied to both sides of the plate, and the respective electric insulating layers are applied while being shifted and oriented in a direction of 90 degrees.

In the above construction, the mixing ratio of the acicular magnetic particles and the acicular nonmagnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and It is preferable that the compounding ratio with respect to the acicular non-magnetic inorganic particles is 70:30 to 30:70 by weight.

Next, a fifth printed wiring board according to the present invention forms an electric insulating layer using a binder in which needle-like magnetic particles and needle-like non-magnetic inorganic particles are dispersed, and the electric insulating layer is printed wiring. The coating is performed on both sides of the plate, and the needle-shaped magnetic particles and the needle-shaped non-magnetic inorganic particles of the respective electric insulating layers are isotropically coated.

In the above structure, the mixing ratio of the acicular magnetic particles and the acicular non-magnetic inorganic particles to the binder in the electric insulating layer is 50:50 to 20:80 by weight, and It is preferable that the compounding ratio with respect to the acicular non-magnetic inorganic particles is 70:30 to 30:70 by weight.

In the first to fifth aspects of the present invention, the printed wiring board is preferably a flexible printed wiring board. In the first and second aspects of the invention, it is preferable that the plate-like ratio of the plate-like magnetic particles is 3 to 8.

In the first or third aspect of the invention, the plate-like inorganic particles preferably have a plate-like ratio of 3 to 8. In the second or fourth aspect of the invention, it is preferable that the acicular inorganic particles have an acicular ratio of 3 to 30.

In the third or fourth aspect of the invention, it is preferable that the acicular magnetic particles have an acicular ratio of 3 to 30. In the first to fifth aspects of the present invention, the thickness of the electric insulating layer is preferably in the range of 4 to 200 μm.

[0020]

According to the first printed wiring board of the present invention, it is possible to provide a printed wiring board for reducing a warp occurring after the production of a multi-layer substrate and effective for preventing electromagnetic interference against a magnetic field. it can. That is, since the shape of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles in the electric insulating layer is a plate-like shape, the force required for the warp occurring during the printed wiring board manufacturing process is directed toward the XY axis direction. Can be dispersed in one way. Further, since magnetic particles are contained in the electric insulating layer, it is effective against a magnetic field.

According to the second printed wiring board of the present invention, it is possible to provide a printed wiring board capable of reducing warpage occurring after the production of a multilayer substrate and effective against electromagnetic interference against a magnetic field. That is, the plate-like magnetic particles in the electric insulating layer can isotropically disperse the force required for warpage occurring during the manufacturing process of the printed wiring board in the XY axis directions. Further, the acicular nonmagnetic inorganic particles in the electric insulating layer are:
Since each is applied shifted 90 degrees, X
The strength in the Y-axis direction can be compensated. In addition, since magnetic particles are contained in the electric insulating layer, it is effective against a magnetic field.

According to the third printed wiring board of the present invention, it is possible to provide a printed wiring board capable of reducing warpage occurring after the production of a multilayer substrate and effective against electromagnetic interference against magnetic fields. That is, the needle-like magnetic particles in the electric insulating layer are applied with a shift in the direction of 90 degrees, respectively, and the orientation is further applied, so that the strength in the XY axis direction can be compensated. Furthermore, the plate-like non-magnetic inorganic particles in the electric insulating layer are:
The force required for the sled that occurs during the printed wiring board manufacturing process,
The particles can be isotropically dispersed in the XY axis directions. Also, since magnetic particles are included in the electric insulating layer,
Effective for magnetic fields.

According to the fourth printed wiring board of the present invention, it is possible to provide a printed wiring board for reducing a warp occurring after the production of a multilayer substrate and effective for preventing electromagnetic interference against a magnetic field. That is, the needle-like magnetic particles in the electric insulating layer are applied with a shift in the direction of 90 degrees, respectively, and the orientation is further applied, so that the strength in the XY axis direction can be compensated. Further, the acicular nonmagnetic inorganic particles in the electric insulating layer are:
Since each is applied shifted 90 degrees, X
The strength in the Y-axis direction can be compensated. In addition, since magnetic particles are contained in the electric insulating layer, it is effective against a magnetic field.

According to the fifth printed wiring board of the present invention, it is possible to provide a printed wiring board for reducing the warpage occurring after the production of the multilayer substrate and effective for preventing electromagnetic interference against a magnetic field. That is, since the acicular magnetic particles and the acicular non-magnetic inorganic particles in the electric insulating layer are each applied isotropically, the force required for the sled can be dispersed. In addition, since magnetic particles are contained in the electric insulating layer, it is effective against a magnetic field. Further, it is possible to provide a flexible printed wiring board which is effective against magnetic fields for electromagnetic wave interference. That is, since the electric insulating layer contains magnetic particles, it is effective against a magnetic field.

[0025]

The present invention will be described more specifically with reference to the following examples. In the following examples, the measurement method was as follows. (1) Warpage Amount of warpage was measured with a ruler. (2) Electromagnetic waves Unwanted radiation of electromagnetic waves was measured at 50 MHz and 150 MHz.

Hereinafter, a first embodiment will be described in detail by taking a six-layer printed wiring board as an example. FIG. 1 is a cross-sectional view of a printed wiring board 5 of the present embodiment. The mixing ratio of the plate-like magnetic particles 2 and the plate-like non-magnetic inorganic particles 3 to the binder 1 in the electric insulating layer is 50 by weight. : 50-2
0:80 is preferred (Examples 1 and 2). Reference numeral 4 indicates a wiring pattern, and L1 to L6 indicate printed wiring surfaces of six layers.

If the mixing ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the electric insulating layer becomes insufficient, and the plate-like magnetic particles and the plate-like non-magnetic inorganic particles become insufficient. The filling property and the dispersibility of are reduced (Comparative Example 4). Conversely, when the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparative Example 5).

The mixing ratio of the plate-like magnetic particles to the plate-like non-magnetic inorganic particles is 70:30 to 3 by weight.
0:70 is preferred (Examples 3 and 4). If the mixing ratio of the plate-like magnetic particles to the plate-like non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 6). Conversely, if the amount is less than 30 parts by weight, the effectiveness with respect to the magnetic field does not appear (Comparative Example 7).

The plate-like ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles in the electric insulating layer is preferably 3 to 8 (Example 5,
6). When the plate ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles is less than 3, the arrangement in the electric insulating layer becomes worse,
The strength in the XY axis directions cannot be compensated (Comparative Examples 8 and 9). On the other hand, if the plate ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles is larger than 8, the particles may be broken during dispersion, and the strength in the XY-axis directions cannot be compensated.

Examples of the plate-like magnetic particles used in the electric insulating layer include BaFe ₁₂ O ₁₉ and SrFe ₁₂ O ₁₉ . Examples of the plate-like nonmagnetic inorganic particles used in the electric insulating layer include α-Fe ₂ O ₃ , mica, graphite and the like.

Example 1 The following materials were used as the material of the electric insulating layer. (1) Epoxy acrylate resin: 40 parts by weight (2) Acrylate monomer: 10 parts by weight (3) Plate-shaped magnetic particles BaFe ₁₂ O ₁₉ (plate diameter 0.1 μm, specific surface area 50 m ² / g, tabular ratio 5): 25 parts by weight (4) tabular nonmagnetic inorganic particles (tabular diameter 0.1 μm, specific surface area 50)
m ² / g, plate ratio 5): 25 parts by weight After mixing the above materials with a mixer, kneading with a pressure kneader, further diluting with a solvent, and then dispersing with a sand mill to obtain a predetermined binder for an electric insulating layer. Was. Next, the prepared binder for an electric insulating layer was applied on a substrate using a screen printer, and dried at 150 ° C. for 60 minutes. The thickness of the electric insulating layer was 10 μm. Further, after performing a plating process, a pattern was formed to produce a printed wiring board.

(Examples 2 to 4) Printed wiring boards of Examples 2 to 4 were obtained in the same manner as in Example 1 except that the material composition of the electric insulating layer was changed.

Example 5 A printed wiring board of Example 5 was obtained in the same manner as in Example 1 except that the plate ratio of the plate-like magnetic particles in the electric insulating layer was changed.

Example 6 Example 6 was performed in the same manner as in Example 1 except that the plate ratio of the plate-shaped non-magnetic particles in the electric insulating layer was changed.
Was obtained.

Comparative Example 1 As a comparison, a commercially available resin for build-up was used. (Comparative Examples 2 to 7) Printed wiring boards of Comparative Examples 2 to 7 were obtained in the same manner as in Example 1 except that the material composition of the electric insulating layer was changed.

Comparative Example 8 A printed wiring board of Comparative Example 8 was obtained in the same manner as in Example 1 except that the plate ratio of the plate-like magnetic particles in the electric insulating layer was changed.

Comparative Example 9 A printed wiring board of Comparative Example 9 was obtained in the same manner as in Example 1 except that the plate ratio of the plate-like magnetic particles in the electric insulating layer was changed.

Table 1 shows the composition of the binder for the electrical insulating layer of the printed wiring board obtained as described above, and Table 2 shows the results of measuring the performance of the printed wiring board. Next, as a second embodiment, a six-layer printed wiring board will be described specifically. FIG. 2 is a cross-sectional view of the printed wiring board 5 of the present embodiment, which is composed of the plate-like magnetic particles 2, the acicular non-magnetic inorganic particles 6, and the binder 1 in the electric insulating layer. The mixing ratio of the plate-like magnetic particles 2 and the acicular non-magnetic inorganic particles 6 to the binder 1 is preferably 50:50 to 20:80 by weight (Examples 7, 8).

If the mixing ratio of the plate-like magnetic particles and the acicular non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the electric insulating layer becomes insufficient, and the plate-like magnetic particles and the acicular non-magnetic inorganic particles become insufficient. The filling property and the dispersibility of are reduced (Comparative Example 10). Conversely, when the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparative Example 11).

The mixing ratio of the plate-like magnetic particles to the acicular non-magnetic inorganic particles is 70:30 to 3 by weight.
0:70 is preferred (Examples 9 and 10). If the mixing ratio of the plate-like magnetic particles to the needle-like non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 12). On the other hand, when the amount is less than 30 parts by weight, the effectiveness with respect to the magnetic field does not appear (Comparative Example 13).

The plate-like ratio of the plate-like magnetic particles in the electric insulating layer is 3
To 8 are preferred (Example 11). If the plate-like ratio of the plate-like magnetic particles is smaller than 3, the arrangement during electrical insulation becomes worse, and X
The strength in the Y-axis direction cannot be compensated (Comparative Example 1)
4). On the other hand, if the plate-like ratio of the plate-like magnetic particles is more than 8, the particles are destroyed at the time of dispersion, so that the strength in the XY-axis directions cannot be compensated.

Examples of the plate-like magnetic particles used in the electric insulating layer include BaFe ₁₂ O ₁₉ and SrFe ₁₂ O ₁₉ . The acicular ratio of the acicular nonmagnetic particles in the electric insulating layer is 3 to 3.
0 is preferred (Example 12). When the acicular ratio of the acicular inorganic particles is less than 3, the arrangement in the electric insulating layer becomes poor,
The strength in the XY axis directions cannot be compensated (Comparative Example 1)
5). On the other hand, if the acicular ratio of the acicular non-magnetic particles is greater than 30, the particles will be destroyed during dispersion, making it impossible to compensate for the strength in the XY axis directions.

Examples of the acicular nonmagnetic inorganic particles used in the electric insulating layer include α-Fe ₂ O ₃ , ZnO, ZnSiO
₄ mag. (Example 7) The following materials were used as the material of the electric insulating layer.

(1) Epoxy acrylate resin: 40 parts by weight (2) Acrylate monomer: 10 parts by weight (3) Plate-shaped magnetic particles BaFe ₁₂ O ₁₉ (plate diameter: 0.1 μm) ,
Specific surface area 50 m ² / g, plate ratio 5): 25 parts by weight (4) Acicular non-magnetic inorganic particles ZnO (major axis length 0.12 μm)
m, short axis length 0.006 μm, specific surface area 35 m ² / g):
25 parts by weight The above materials were mixed with a mixer, kneaded with a pressure kneader, further diluted with a solvent, and then dispersed with a sand mill to obtain a predetermined binder for an electric insulating layer. Next, the prepared binder for an electric insulating layer was applied to one surface of a substrate using a screen printer, and dried at 150 ° C. for 60 minutes. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, and the binder for the electrical insulating layer was printed and dried. The thickness of the electric insulating layer was 10 μm. Next, after performing a plating process, a pattern is formed,
A printed wiring board was manufactured.

Examples 8 to 10 Printed wiring boards of Examples 8 to 10 were obtained in the same manner as in Example 7, except that the material composition of the electric insulating layer was changed.

Example 11 Example 1 was carried out in the same manner as in Example 7 except that the plate ratio of the plate-like magnetic particles in the electric insulating layer was changed.
Thus, No. 1 printed wiring board was obtained.

Example 12 A printed wiring board of Example 12 was obtained in the same manner as in Example 7 except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

Comparative Examples 10 to 13 Comparative Examples 10 to 1 were performed in the same manner as in Example 7 except that the material composition of the electric insulating layer was changed.
3 was obtained.

Comparative Example 14 Comparative Example 1 was conducted in the same manner as in Example 7 except that the plate ratio of the plate-like magnetic particles in the electric insulating layer was changed.
4 was obtained.

Comparative Example 15 A printed wiring board of Comparative Example 15 was obtained in the same manner as in Example 7, except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

Table 1 shows the composition of the electric insulating layer of the printed wiring board obtained as described above, and Table 4 shows the results of measuring the performance of the printed wiring board. Evaluation items are shown below.

[0052]

[Table 1]

[0053]

[Table 2]

As is clear from the results of the above Examples and Comparative Examples, it was confirmed that the printed wiring boards of the Examples of the present invention were excellent in the amount of warpage and unnecessary radiation of electromagnetic waves. Next, as a third embodiment, a six-layer printed wiring board will be described specifically. FIG. 3 shows a printed wiring board 5 according to this embodiment.
The mixing ratio of the acicular magnetic particles 7 and the plate-like non-magnetic inorganic particles 4 to the binder 1 in the electric insulating layer 5 is preferably 50:50 to 20:80 by weight. Examples 13, 14).

When the mixing ratio of the acicular magnetic particles and the plate-like non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the electric insulating layer becomes insufficient, and the acicular magnetic particles and the plate-like non-magnetic inorganic particles become insufficient. The filling property and the dispersibility of are reduced (Comparative Example 18). Conversely, when the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparative Example 19).

The mixing ratio of the acicular magnetic particles to the plate-like non-magnetic inorganic particles is 70:30 to 3 by weight.
0:70 is preferred (Examples 15 and 16). If the mixing ratio of the acicular magnetic particles to the plate-like nonmagnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 20). Conversely, if the amount is less than 30 parts by weight, the effectiveness with respect to the magnetic field does not appear (Comparative Example 21).

The acicular ratio of the acicular magnetic particles in the solder resist layer is preferably from 3 to 30 (Example 17). If the acicular ratio of the acicular magnetic particles is less than 3, the arrangement in the electric insulating layer becomes poor, and the strength in the XY axis directions cannot be compensated (Comparative Example 22). On the other hand, if the acicular ratio of the acicular magnetic particles is greater than 30, the particles will be destroyed during dispersion, making it impossible to compensate for the strength in the XY axis directions.

Examples of the acicular magnetic particles used in the electric insulating layer include γ-Fe ₂ O ₃ , CrO ₂ , and Co-γFe ₂ O ₃
Etc. are raised. The tabular ratio of the tabular nonmagnetic inorganic particles in the electric insulating layer is preferably from 3 to 8 (Example 18). When the tabular ratio of the tabular non-magnetic inorganic particles is less than 3, the arrangement in the electric insulating layer becomes poor, and the strength in the XY axis directions cannot be compensated (Comparative Example 23). On the other hand, if the acicular ratio of the plate-like non-magnetic inorganic particles is larger than 8, the particles will be broken during dispersion, and the strength in the XY axis direction cannot be compensated.

Examples of plate-like non-magnetic inorganic particles used in the electric insulating layer include α-Fe ₂ O ₃ , mica, graphite and the like. (Example 13) The following materials were used as the material of the electrical insulating layer.

Preparation of binder for electric insulating layer; (1) epoxy acrylate resin: 40 parts by weight (2) acrylate monomer: 10 parts by weight (3) needle-like magnetic particles γ-Fe ₂ O ₃ (major axis length 0. 12 μm,
Short axis length 0.006 μm, specific surface area 35 m ² / g): 25
Parts by weight (4) Plate-like non-magnetic inorganic particles (plate diameter: 0.1 μm, specific surface area: 50 m ² / g, plate ratio: 5): 25 parts by weight After mixing the above materials with a mixer, kneading with a pressure kneader, Further, the mixture was diluted with a solvent and dispersed by a sand mill to obtain a predetermined binder for an electric insulating layer. Next, the prepared binder for an electric insulating layer was applied to one surface of a substrate using a screen printer, oriented in an undried state, and dried at 150 ° C. for 60 minutes. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, the binder for the electrical insulating layer was printed, oriented, and then dried. The thickness of the electric insulating layer was 10 μm. Next, a pattern was formed to produce a printed wiring board.

(Examples 14 to 16) Except that the material composition of the electric insulating layer was changed, the same procedure as in Example 13 was repeated.
Sixteen printed wiring boards were obtained.

Example 17 A printed wiring board of Example 17 was obtained in the same manner as in Example 13 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

(Example 18) A printed wiring board of Example 18 was obtained in the same manner as in Example 13 except that the plate ratio of the plate-like magnetic inorganic particles of the electric insulating layer was changed.

(Comparative Examples 16 to 21) Comparative Examples 16 to 21 were performed in the same manner as in Example 13 except that the material composition of the electrical insulating layer was changed.
21 printed wiring boards were obtained.

Comparative Example 22 A printed wiring board of Comparative Example 22 was obtained in the same manner as in Example 13 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

Comparative Example 23 A printed wiring board of Comparative Example 23 was obtained in the same manner as in Example 13 except that the plate ratio of the plate-shaped nonmagnetic inorganic particles in the electric insulating layer was changed.

Table 2 shows the composition of the electric insulating layer of the printed wiring board obtained as described above, and Table 5 shows the results of measuring the performance of the printed wiring board. As is clear from the results of the above Examples and Comparative Examples, it is understood that the printed wiring board obtained by the configuration of the present invention is excellent in the amount of warpage and unnecessary radiation of electromagnetic waves.

Next, as a fourth embodiment, a six-layer printed wiring board will be described as an example. FIG. 4 is a cross-sectional view of the printed wiring board 5 of the present embodiment.
The mixing ratio of the needle-like magnetic particles 7 and the needle-like non-magnetic inorganic particles 6 to the binder 1 is 50:50 to 20:
80 is preferred (Examples 19 and 20).

When the mixing ratio of the acicular magnetic particles and the acicular nonmagnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the electric insulating layer becomes insufficient, and the acicular magnetic particles and the acicular nonmagnetic inorganic particles are insufficient. The filling property and the dispersibility of are reduced (Comparative Example 22). Conversely, if the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparative Example 23).

The mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles is 70:30 to 3 by weight.
0:70 is preferred (Examples 21 and 22). If the mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 24). Conversely, if the amount is less than 30 parts by weight, the effectiveness with respect to the magnetic field does not appear (Comparative Example 25).

The acicular magnetic particles in the electrically insulating layer have an acicular ratio of 3
~ 30 is preferred (Example 23). When the acicular ratio of the acicular magnetic particles is less than 3, the arrangement in the electric insulating layer becomes poor, and the strength in the XY axis directions cannot be compensated (Comparative Example 26). On the other hand, if the acicular ratio of the acicular magnetic particles is larger than 30, the particles may be destroyed at the time of dispersion.
The axial strength cannot be compensated.

Examples of the acicular magnetic particles used in the electric insulating layer include γ-Fe ₂ O ₃ , CrO ₂ and Co-γFe ₂ O ₃
Etc. are raised. The acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer is preferably from 3 to 30 (Example 24). If the acicular ratio of the acicular nonmagnetic inorganic particles is less than 3, the arrangement in the electric insulating layer becomes poor, and the strength in the XY axis directions cannot be compensated (Comparative Example 26). On the other hand, if the acicular ratio of the acicular non-magnetic inorganic particles is larger than 30, the particles are destroyed at the time of dispersion, so that the strength in the XY axis directions cannot be compensated (Comparative Example 27).

Examples of the acicular nonmagnetic inorganic particles used in the electric insulating layer include α-Fe ₂ O ₃ , ZnO, ZnSiO
₄ mag. (Example 19) The following materials were used as the material of the electric insulating layer.

Preparation of binder for electric insulating layer; (1) epoxy acrylate resin: 40 parts by weight (2) acrylate monomer: 10 parts by weight (3) needle-like magnetic particles γ-Fe ₂ O ₃ (major axis length 0. 12 μm,
Short axis length 0.006 μm, specific surface area 35 m ² / g): 25
Parts by weight (4) Acicular nonmagnetic inorganic particles ZnO (major axis length 0.12μ)
m, short axis length 0.006 μm, specific surface area 35 m ² / g):
25 parts by weight The above materials were mixed with a mixer, kneaded with a pressure kneader, further diluted with a solvent, and then dispersed with a sand mill to obtain a predetermined binder for an electric insulating layer. Next, the prepared binder for an electric insulating layer was applied to one surface of a substrate using a screen printer, oriented in an undried state, and dried at 150 ° C. for 60 minutes. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, the binder for the electrical insulating layer was printed, oriented, and then dried. The thickness of the electric insulating layer was 10 μm. Next, after performing a plating process, a pattern was formed to produce a printed wiring board.

(Examples 20 to 22) Except that the material composition of the electric insulating layer was changed, the same procedure as in Example 19 was repeated.
Thus, 22 printed wiring boards were obtained.

Example 23 A printed wiring board of Example 23 was obtained in the same manner as in Example 19 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

Example 24 A printed wiring board of Example 24 was obtained in the same manner as in Example 19, except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

(Comparative Examples 22 to 25) Examples 22 to 25 were performed in the same manner as in Example 19 except that the material composition of the electric insulating layer was changed.
24 printed wiring boards were obtained.

(Comparative Example 26) A printed wiring board of Comparative Example 25 was obtained in the same manner as in Example 19 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

Comparative Example 27 A printed wiring board of Comparative Example 26 was obtained in the same manner as in Example 19 except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

Table 3 shows the composition of the electrical insulating layer of the printed wiring board obtained as described above, and Table 4 shows the results of measuring the performance of the printed wiring board. Evaluation items are shown below.

[0082]

[Table 3]

[0083]

[Table 4]

As is clear from the results of the above Examples and Comparative Examples, it is understood that the printed wiring board obtained by the configuration of the present invention is excellent in the amount of warpage and unnecessary radiation of electromagnetic waves. Next, as a fifth embodiment, a six-layer printed wiring board will be described in detail. FIG. 5 shows a cross-sectional view of the printed wiring board 5 of the present embodiment. The mixing ratio of the acicular magnetic particles 8 and the acicular non-magnetic inorganic particles 9 to the binder 1 in the electric insulating layer 5 is expressed by weight. 50:50 to 20:80 is preferred (Examples 25 and 26).

If the mixing ratio of the acicular magnetic particles and the acicular non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the electric insulating layer becomes insufficient, and the acicular magnetic particles and the acicular non-magnetic inorganic particles become insufficient. The filling property and the dispersibility of are reduced (Comparative Example 28). Conversely, when the amount is less than 20 parts by weight, it becomes impossible to disperse the force required for the sled (Comparative Example 29).

The mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles is 70:30 to 3 by weight.
0:70 is preferred (Examples 27 and 28). If the mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 30). Conversely, if the amount is less than 30 parts by weight, the effectiveness with respect to the magnetic field does not appear (Comparative Example 31).

The acicular ratio of acicular magnetic particles in the electric insulating layer is 3
To 30 are preferable (Example 29). When the acicular ratio of the acicular magnetic particles is smaller than 3, the arrangement in the electric insulating layer cannot be made isotropic (Comparative Example 32). On the other hand, if the acicular ratio of the acicular magnetic particles is greater than 30, the particles will be destroyed during dispersion.

Examples of Acicular Magnetic Particles Used in Electrical Insulating Layer
Γ-Fe_TwoO_Three, CrO_Two, Co-γFe_TwoO_Three
Etc. are raised. Acicular nonmagnetic inorganic particles in the electrical insulation layer
Is preferably 3 to 30 (Example 30). Acicular
Electrical insulation when needle ratio of magnetic inorganic particles is less than 3
The arrangement in the layer cannot be made isotropic (Comparative Example
32). On the other hand, from the acicular ratio of acicular nonmagnetic inorganic particles of 30
Larger particles will break down during dispersion (comparison
Example 33). Acicular non-magnetic inorganic particles used in electrical insulation layers
Examples of the element include α-Fe _TwoO_Three, ZnO, ZnSiO_Four
Etc. are raised.

Example 25 The following materials were used as the material of the electric insulating layer. Preparation of binder for electric insulating layer; (1) Epoxy acrylate resin: 40 parts by weight (2) Acrylate monomer: 10 parts by weight (3) Acicular magnetic particles γ-Fe2O3 (major axis length 0.12μ)
m, short axis length 0.006 μm, specific surface area 35 m ² / g):
25 parts by weight (4) Acicular nonmagnetic inorganic particles ZnO (major axis length 0.12μ)
m, short axis length 0.006 μm, specific surface area 35 m ² / g):
25 parts by weight The above materials were mixed with a mixer, kneaded with a pressure kneader, further diluted with a solvent, and then dispersed with a sand mill to obtain a predetermined binder for an electric insulating layer. Next, the prepared binder for an electric insulating layer is applied to both surfaces of the substrate using a screen printer, and after applying an AC magnetic field to make the particle arrangement isotropic in an undried state, drying is performed at 150 ° C. and 60 ° C. Minutes. The thickness of the electric insulating layer was 10 μm. Next, after performing a plating process, a pattern is formed,
A printed wiring board was manufactured.

(Examples 26 to 28) Examples 26 to 28 were performed in the same manner as in Example 25 except that the material composition of the electric insulating layer was changed.
28 printed wiring boards were obtained.

Example 29 A printed wiring board of Example 29 was obtained in the same manner as in Example 25 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

(Example 30) A printed wiring board of Example 30 was obtained in the same manner as in Example 25 except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

(Comparative Examples 28 to 31) Examples 28 to 31 were performed in the same manner as in Example 25 except that the material composition of the electric insulating layer was changed.
31 printed wiring boards were obtained.

(Comparative Example 32) A printed wiring board of Comparative Example 32 was obtained in the same manner as in Example 25 except that the acicular ratio of the acicular magnetic particles in the electric insulating layer was changed.

Comparative Example 33 A printed wiring board of Comparative Example 33 was obtained in the same manner as in Example 25 except that the acicular ratio of the acicular nonmagnetic inorganic particles in the electric insulating layer was changed.

Table 5 shows the composition of the electrical insulating layer of the printed wiring board obtained as described above, and Table 6 shows the results of measuring the performance of the printed wiring board.

[0097]

[Table 5]

[0098]

[Table 6]

As is clear from the results of the above Examples and Comparative Examples, it is understood that the printed wiring board obtained by the configuration of the present invention is excellent in the amount of warpage and unnecessary radiation of electromagnetic waves. Further effects can be expected if two or more electric insulating layers each having plate-like or needle-like magnetic particles, non-magnetic inorganic particles, and a binder are arranged on the front and back of the multilayer substrate. The first to fifth embodiments can be applied even when the printed wiring board is a flexible printed wiring board.

[0100]

As described above, according to the present invention, by using a binder in which magnetic particles and inorganic particles are dispersed as an electric insulating layer, warpage occurring after manufacturing a multilayer substrate can be reduced. Further, since magnetic particles are contained in the electric insulating layer, a printed wiring board effective against a magnetic field for countermeasures against electromagnetic interference can be provided.

[Brief description of the drawings]

FIG. 1 is a conceptual sectional view of a printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a conceptual sectional view of a printed wiring board according to a second embodiment of the present invention.

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

FIG. 4 is a conceptual sectional view of a printed wiring board according to a fourth embodiment of the present invention.

FIG. 5 is a conceptual sectional view of a printed wiring board according to a fourth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 binder 2 plate-shaped magnetic particles 3 plate-shaped non-magnetic inorganic particles 4 pattern 5 printed wiring board 6 needle-shaped non-magnetic inorganic particles 7 needle-shaped magnetic particles 8 needle-shaped magnetic particles 9 needle-shaped non-magnetic inorganic particles

Claims (15)

[Claims] 1. A printing method comprising: forming an electric insulating layer using a binder in which plate-shaped magnetic particles and plate-shaped non-magnetic inorganic particles are dispersed; and applying the electric insulating layer to both sides of a printed wiring board. Wiring board. 2. The mixing ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles to the binder in the electric insulating layer is 50:50 to 20:80 by weight, and the plate-like magnetic particles have a plate-like non-magnetic inorganic particle weight. The mixing ratio with respect to the magnetic inorganic particles is 70: 3 by weight.
The printed wiring board according to claim 1, wherein the ratio is 0 to 30:70. 3. An electric insulating layer using a binder in which plate-like magnetic particles and needle-like non-magnetic inorganic particles are dispersed, and the electric insulating layer is applied to both sides of a printed wiring board. The printed wiring board, wherein the layers are applied while being shifted in the direction of 90 degrees. 4. The mixing ratio of the plate-like magnetic particles and the needle-like non-magnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and the needle-like non-magnetic particles of the plate-like magnetic particles are mixed. The mixing ratio with respect to the magnetic inorganic particles is 70: 3 by weight.
The printed wiring board according to claim 3, wherein the ratio is 0 to 30:70. 5. An electric insulating layer using a binder in which needle-like magnetic particles and plate-like non-magnetic inorganic particles are dispersed, and applying the electric insulating layer to both sides of a printed wiring board, A printed wiring board, wherein the layers are applied in a shifted and oriented direction of 90 degrees. 6. The mixing ratio of the acicular magnetic particles and the plate-like non-magnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and the acicular magnetic particles have a plate-like non-magnetic inorganic particle ratio. The mixing ratio with respect to the magnetic inorganic particles is 70: 3 by weight.
The printed wiring board according to claim 5, wherein the ratio is 0 to 30:70. 7. An electric insulating layer using a binder in which needle-like magnetic particles and needle-like non-magnetic inorganic particles are dispersed, and the electric insulating layer is applied to both sides of a printed wiring board. A printed wiring board characterized in that the layers are applied in a direction shifted by 90 degrees and oriented. 8. The mixing ratio of the acicular magnetic particles and the acicular non-magnetic inorganic particles to the binder in the electric insulating layer is 50:50 to 20:80 by weight, and the acicular magnetic particles are acicular non-magnetic particles. The mixing ratio with respect to the magnetic inorganic particles is 70: 3 by weight.
The printed wiring board according to claim 7, wherein the ratio is 0 to 30:70. 9. An electric insulating layer using a binder in which needle-like magnetic particles and needle-like non-magnetic inorganic particles are dispersed, and applying said electric insulating layer to both sides of a printed wiring board; A printed wiring board, wherein a needle-like magnetic particle and a needle-like non-magnetic inorganic particle of a layer are isotropically applied. 10. The compounding ratio of the acicular magnetic particles and the acicular non-magnetic inorganic particles in the electric insulating layer to the binder is 50:50 to 20:80 by weight, and the acicular magnetic particles are acicular non-magnetic particles. The mixing ratio with respect to the magnetic inorganic particles is 70:
The printed wiring board according to claim 9, wherein the ratio is 30 to 30:70. 11. The printed wiring board according to claim 1, wherein the printed wiring board is a flexible printed wiring board. 12. The printed wiring board according to claim 1, wherein the tabular ratio of the tabular magnetic particles is 3 to 8. 13. The printed wiring board according to claim 1, wherein a tabular ratio of the tabular inorganic particles is 3 to 8. 14. The printed wiring board according to claim 3, wherein the acicular inorganic particles have an acicular ratio of 3 to 30. 15. The printed wiring board according to claim 5, wherein the acicular ratio of the acicular magnetic particles is 3 to 30.