JPH09283939A - Printed-wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printed-wiring board whose warp is reduced after the finish of its production process and which achieves effective measures of electromagnetic waves against magnetic field by a method wherein solder resist layers in which sheetlike magnetic particles, sheetlike nonmagnetic particles and a bonding agent are mixed are formed on the surface and the rear of a multilayer board. SOLUTION: First, a first board 3A in which wiring patterns 2a, 2b are formed on the surface and the rear of a prepreg 1a and a second board 3B in which wiring patterns 2a, 2b are formed on the surface and the rear of a prepreg 1b are bonded via a prepreg 1c, and a four-layer multilayer board 4 is formed. Solder resist layers 5a, 5b in which sheetlilke magnetic particles, sheetlike nonmagnetic particles and a bonding agent are mixed are formed on the surface and the rear of the four-layer multilayer board 4, Thereby, a warp which is generated after the manufacture of the multilayer board can be reduced. In addition, since the magnetic particles are contained in the solder resist layers 5a, 5b, it is possible to obtain a printed-wiring board for the effective measures of electromagnetic wave disturbance against a magnetic field.

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 which is free from warpage of a substrate generated after manufacturing a multi-layered substrate and is effective against a magnetic field to prevent electromagnetic interference.

[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.

Specifically, in the past, in order to make the printed wiring board thinner while making it multilayer, each core material and prepreg are thinly manufactured.

[0004]

However, when each core material and prepreg are made thin, there is a problem that warpage is likely to occur after the manufacturing process of the printed wiring board 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 the devices, there is a problem that they become a source of noise.

It is an object of the present invention to provide a printed wiring board which can be formed in multiple layers while reducing the thickness of the board and has less warpage after the manufacturing process. Another object of the present invention is to provide a printed wiring board which is effective against electromagnetic fields and is a countermeasure for electromagnetic interference.

[0007]

The printed wiring board of the present invention is characterized in that any one of the following solder resist layers is formed on the front and back surfaces of a multilayer substrate. The solder resist layer is composed of a plate-shaped magnetic particle, a plate-shaped non-magnetic particle and a binder, or a needle-shaped magnetic particle, a plate-shaped non-magnetic inorganic particle and a binder, which are oriented by shifting 90 degrees. It is either a solder resist layer arranged, or a solder resist layer in which needle-shaped magnetic particles and needle-shaped non-magnetic inorganic particles and binders which are respectively shifted in the direction of 90 degrees are arranged.

By forming such a solder resist layer, it is possible to obtain a printed wiring board which has less warpage of the multilayer substrate and is effective against electromagnetic fields against electromagnetic interference.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A printed wiring board according to claim 1 of the present invention is a solder in which plate-like magnetic particles, plate-like non-magnetic particles and a binder are arranged on the front and back of a multilayer substrate in order to solve the above problems. The resist layer is formed, and the mixing ratio of the plate-shaped magnetic particles and the plate-shaped non-magnetic inorganic particles in the solder resist layer to the binder is “50:50 to 20:80” by weight, and the plate-shaped magnetic particles The mixing ratio to the non-magnetic inorganic particles,
The weight ratio is "70:30 to 30:70".

According to this structure, it is possible to provide a printed wiring board which is effective in preventing electromagnetic interference against a magnetic field by reducing the warpage that occurs after the manufacture of the multilayer board. That is, since the plate-like magnetic particles and the plate-like non-magnetic inorganic particles in the solder resist layer have a plate-like shape, the force necessary for the warp generated during the printed wiring board manufacturing process is directed in the XY axis directions. It can be dispersed isotropically. Furthermore, since magnetic particles are included in the solder resist layer,
Effective for magnetic fields.

In order to solve the above problems, a printed wiring board according to a third aspect of the present invention has a solder resist layer having plate-like magnetic particles, acicular non-magnetic inorganic particles and a binder disposed on the front and back surfaces of a multilayer substrate. The solder resist layers on the front and back of the multi-layer substrate are applied with a shift in the direction of 90 degrees, and the compounding ratio of the plate-like magnetic particles and the acicular non-magnetic inorganic particles in the solder resist layer to the binder is a weight ratio. "50:50
~ 20:80 ", and the mixing ratio of plate-like magnetic particles to acicular non-magnetic inorganic particles is" 70: 30-30: 70 "by weight.
It is.

According to this structure, it is possible to provide a printed wiring board which is effective in preventing electromagnetic interference against a magnetic field by reducing the warpage that occurs after the manufacture of the multilayer board. That is, the plate-like magnetic particles in the solder resist layer can isotropically disperse the force necessary for the warp generated during the printed wiring board manufacturing process in the XY axis directions. Furthermore, the acicular non-magnetic inorganic particles in the solder resist layer are
Since the coating is shifted in 90 degrees, the strength in the XY axis directions can be supplemented. Further, since the solder resist layer contains magnetic particles, it is effective against a magnetic field.

In order to solve the above-mentioned problems, a printed wiring board according to a fifth aspect of the present invention comprises needle-like magnetic particles and plate-like non-magnetic inorganic particles, which are oriented on the front and back sides of a multi-layer substrate by being shifted in 90 ° directions. A solder resist with a binder is formed, and the mixing ratio of the acicular magnetic particles and plate-like non-magnetic inorganic particles in the solder resist layer to the binder is “50:50 to 20:80” by weight, and The mixing ratio of the spherical magnetic particles to the plate-like non-magnetic inorganic particles is 70:30 by weight.
~ 30:70 ”.

According to this structure, it is possible to provide a printed wiring board which is effective in preventing electromagnetic interference against the magnetic field by reducing the warpage that occurs after manufacturing the multilayer substrate. That is, the acicular magnetic particles in the solder resist layer are 9
The coating is shifted in the 0-degree direction and is further oriented so that the strength in the XY-axis directions can be compensated. Furthermore, the plate-shaped non-magnetic inorganic particles in the solder resist layer can isotropically disperse the force necessary for the warpage that occurs during the printed wiring board manufacturing process, in the XY axis directions. Further, since the magnetic particles are contained in the solder resist layer,
Effective for magnetic fields.

In order to solve the above-mentioned problems, the printed wiring board according to claim 7 of the present invention comprises needle-shaped magnetic particles and needle-shaped non-magnetic inorganic particles, which are oriented by being shifted in the direction of 90 degrees, respectively, on the front and back of the multilayer substrate. A solder resist layer with a binder is formed, and the mixing ratio of the acicular magnetic particles and acicular nonmagnetic inorganic particles in the solder resist layer to the binder is “50:50 to 20:80” by weight, and The mixing ratio of acicular magnetic particles to acicular non-magnetic inorganic particles is 70:30 by weight.
~ 30:70 ”.

According to this structure, it is possible to provide a printed wiring board which is effective in preventing electromagnetic interference against a magnetic field by reducing warpage that occurs after manufacturing a multilayer substrate. That is, the acicular magnetic particles in the solder resist layer are 9
The coating is shifted in the 0-degree direction and is further oriented so that the strength in the XY-axis directions can be compensated. Furthermore, the acicular non-magnetic inorganic particles in the solder resist layer are
Since the coating is shifted in 90 degrees, the strength in the XY axis directions can be supplemented. Further, since the solder resist layer contains magnetic particles, it is effective against a magnetic field.

Embodiments of the present invention will be described below by taking a four-layer printed wiring board as an example. 1A to 1C show a manufacturing process of a four-layer printed wiring board. First, as shown in FIG. 1A, a first substrate 3A having wiring patterns 2a and 2b formed on the front and back surfaces of a prepreg 1a and a second substrate 3A having wiring patterns 2a and 2b formed on the front and back surfaces of the prepreg 1b. Substrate 3B of FIG. 1 and intervening prepreg 1c therebetween, and molded as shown in FIG. 1 (b) to form a four-layered multilayer substrate 4, and the printed wiring board of the present invention has the structure shown in FIG. As shown, solder resist layers 5a and 5b having the following compositions are provided on the front and back of the four-layered multilayer substrate 4 to complete the process.

[First Embodiment] Examples 1 to 6 below show [First Embodiment], and Comparative Examples 1 to 9 evaluate [First Embodiment]. It shows a comparative example required to do so. [Table 1] shows the material composition of each solder resist layer.

[0019]

[Table 1]

(Example 1) In this (Example 1), the solder resist layers 5a and 5b are composed of a composition of plate-like magnetic particles 6, plate-like non-magnetic inorganic particles 7 and a binder as shown in FIG. The following solder resist ink was used.

Preparation of Ink for Solder Resist Layer; Epoxy Acrylate Resin: 40 parts by Weight Acrylate Monomer: 10 parts by Weight Plate-like Magnetic Particles BaFe ₁₂ O ₁₉ (Plate Diameter 0.1 μm, Specific surface area 50 m ² / g, plate-shaped ratio 5) 25 parts by weight Plate-shaped non-magnetic inorganic particles α-Fe ₂ O ₃ (plate diameter 0.1 μm, specific surface area 50 m ² / g, plate-shaped Ratio 5) ······ 25 parts by weight The above materials were mixed with a mixer, kneaded with a pressure kneader, diluted with a solvent and dispersed by a sand mill to obtain a predetermined solder resist ink. Next, the produced solder resist ink was applied onto the substrate using a screen printer, and temporarily dried at 150 ° C. for 20 minutes.

(Examples 2 to 4) Printing of (Examples 2 to 4) was performed in the same manner as (Example 1) except that the material composition of the solder resist layer was changed as shown in [Table 1] below. The wiring board was obtained.

Example 5 (Example 5) was carried out in the same manner as in Example 1 except that the plate ratio of the plate-like magnetic particles in the solder resist layer was changed to "3" as shown in [Table 1]. A printed wiring board of Example 5) was obtained.

(Example 6) In the same manner as in Example 1 except that the plate ratio of the plate-shaped nonmagnetic particles in the solder resist layer was changed to "3" as shown in [Table 1] (Example 1) A printed wiring board of Example 6) was obtained.

Comparative Example 1 As a comparison, a commercially available solder resist ink was used. The composition is the same as that of the binder as described above, and is a general one composed of the composition of TiO and BaSO ₄ .

(Comparative Examples 2 to 7) Printing of (Comparative Examples 2 to 7) was carried out in the same manner as (Example 1) except that the material composition of the solder resist layer was changed as shown in [Table 1] below. The wiring board was obtained.

(Comparative Example 8) Comparative Example 8 (Comparative Example) except that the tabular ratio of the tabular magnetic particles in the solder resist layer was changed to "1" as shown in [Table 1]. A printed wiring board of 8) was obtained.

(Comparative Example 9) Comparative Example 9 (Comparative Example) except that the tabular ratio of the tabular magnetic particles in the solder resist layer was changed to "1" as shown in [Table 1]. A printed wiring board of 9) was obtained.

The performance of each printed wiring board thus obtained (its size is 510 × 340 mm) was measured for the following items. The results are shown in [Table 2] below. (1) Amount of warpage The amount of warpage at the four corners of the printed wiring board was measured using a ruler. (2) Electromagnetic waves Unwanted radiation was measured at 50 MHz and 150 MHz.

[0030]

[Table 2]

As is clear from the results of the above-mentioned Examples and Comparative Examples, the printed wiring board obtained by the constitution of the present invention is excellent in the amount of warpage and the unnecessary radiation of electromagnetic waves. As can be seen from this [Table 2], the compounding ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles in the solder resist layer to the binder is “50:50 to 20: 8 by weight ratio”.
0 "is preferable (Examples 1 and 2).

When the compounding ratio of the plate-shaped magnetic particles and the plate-shaped non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the solder resist layer becomes insufficient and the plate-shaped magnetic particles and the plate-shaped non-magnetic inorganic particles are insufficient. The filling property and the dispersibility of the product deteriorate (Comparative Example 4). On the other hand, if the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be supplemented (Comparative Example 5).

Further, the compounding ratio of the plate-like magnetic particles to the plate-like non-magnetic inorganic particles is "70:30 to 3 by weight ratio".
0:70 "is preferred (Examples 1 and 3). If the compounding ratio of the plate-shaped magnetic particles to the plate-shaped non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (comparison). Example 6). Conversely, below 30 parts by weight, the effectiveness against the magnetic field does not appear (Comparative Example 7).

The plate-like ratio of the plate-like magnetic particles and the plate-like nonmagnetic inorganic particles in the solder resist layer is preferably "3 to 8" (Examples 5 and 6). When the plate-like ratio of the plate-like magnetic particles and the plate-like non-magnetic inorganic particles is smaller than "3", the arrangement in the solder resist is deteriorated and the strength in the XY axis directions cannot be compensated (Comparative Examples 8 and 9). ). On the other hand, if the plate-shaped ratio of the plate-shaped magnetic particles and the plate-shaped non-magnetic inorganic particles is larger than "8", the particles will be broken during dispersion, so that the strength in the XY axis directions cannot be compensated.

Examples of the plate-like magnetic particles used in the solder resist layer include BaFe ₁₂ O ₁₉ and SrF.
e ₁₂ O _{19 and the} like. As an example of the plate-shaped non-magnetic inorganic particles used in the solder resist layer, α-Fe ₂ O is used.
_In addition to ₃ , mica, graphite, etc. may be mentioned.

In addition, a plate-like or
A further effect can be expected by coating two or more solder resist layers each having a needle-shaped magnetic particle, a non-magnetic inorganic particle and a binder.

[Second Embodiment] The following Examples 7 to 12 show [Second Embodiment], and Comparative Examples 10 to 10.
Comparative example 15 shows a comparative example necessary for evaluating the [second embodiment]. [Table 3] shows the material composition of each solder resist layer.

[0038]

[Table 3]

(Example 7) In this (Example 7), the solder resist layers 5a and 5b are composed of a composition of plate-like magnetic particles 6, acicular non-magnetic inorganic particles 8 and a binder as shown in FIG. The following solder resist ink was used.

Preparation of Ink for Solder Resist Layer; Epoxy Acrylate Resin: 40 parts by weight Acrylate monomer: 10 parts by weight Plate-like 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 Needle-shaped non-magnetic inorganic particles ZnO (major axis length 0.12 μm, minor axis length 0.006 μm, ratio table 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 by a sand mill to obtain a predetermined solder resist ink. Next, the prepared solder resist ink was applied to one surface of the substrate using a screen printer, and temporary drying was performed at 150 ° C. for 20 minutes to form a solder resist layer 5a. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, a solder resist ink was printed and temporarily dried to form a solder resist layer 5b.

(Examples 8 to 10) Printed wiring boards of (Examples 8 to 10) in the same manner as in (Example 7) except that the material composition of the solder resist layer was changed as shown in [Table 3]. Got

Example 11 Example 11 was repeated except that the plate ratio of the plate-like magnetic particles in the solder resist layer was changed to “3” as shown in Table 3 (Example 11). ) Printed wiring board was obtained.

Example 12 The acicular ratio of the acicular non-magnetic inorganic particles in the solder resist layer was "1" as shown in [Table 3].
A printed wiring board of (Example 12) was obtained in the same manner as in (Example 7) except that the printed wiring board was changed to 0 ″.

(Comparative Examples 10 to 13) Printed wiring boards of (Comparative Examples 10 to 13) were carried out in the same manner as (Example 7) except that the material composition of the solder resist layer was changed as shown in [Table 3]. Got

(Comparative Example 14) The procedure of Comparative Example 14 was repeated except that the tabular ratio of the tabular magnetic particles in the solder resist layer was changed to "1" as shown in [Table 3] (Comparative Example). A printed wiring board of 14) was obtained.

(Comparative Example 15) The procedure of (Example 7) was repeated except that the acicular ratio of the acicular non-magnetic inorganic particles in the solder resist layer was changed to "2" as shown in [Table 3]. A printed wiring board of Comparative Example 15) was obtained.

The performance of each printed wiring board thus obtained (its size is 510 × 340 mm) was measured for the following items. The results are shown in [Table 4] below. (1) Amount of warpage The amount of warpage at the four corners of the printed wiring board was measured using a ruler. (2) Electromagnetic waves Unwanted radiation was measured at 50 MHz and 150 MHz.

[0048]

[Table 4]

As is clear from the results of the above-mentioned Examples and Comparative Examples, the printed wiring board obtained by the constitution of the present invention is excellent in the amount of warpage and unnecessary radiation of electromagnetic waves. As can be seen from this [Table 4], the compounding ratio of the plate-like magnetic particles and the acicular non-magnetic inorganic particles in the solder resist layer to the binder is “50:50 to 20: 8 by weight ratio”.
0 "is preferable (Examples 7 and 8). When the compounding ratio of the plate-shaped magnetic particles and the acicular non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the solder resist layer becomes insufficient, The filling properties and dispersibility of the plate-like magnetic particles and the acicular non-magnetic inorganic particles are deteriorated (Comparative Example 10) .On the contrary, when the amount is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparison). Example 11).

Further, the compounding ratio of the plate-like magnetic particles to the acicular non-magnetic inorganic particles is "70:30 to 3 by weight ratio".
0:70 "is preferred (Examples 9 and 10). The compounding ratio of the plate-like magnetic particles to the acicular non-magnetic inorganic particles is 70.
If it exceeds the weight part, crosstalk may be promoted (Comparative Example 12). On the contrary, when the amount is less than 30 parts by weight, the effectiveness against the magnetic field does not appear (Comparative Example 13).

The plate-like ratio of the plate-like magnetic particles in the solder resist layer is preferably "3 to 8" (Example 11). If the plate-shaped ratio of the plate-shaped magnetic particles is smaller than "3", the arrangement in the solder resist becomes poor and the strength in the XY axis directions cannot be compensated (Comparative Example 14). On the other hand, if the plate-shaped ratio of the plate-shaped magnetic particles is larger than "8", the particles are broken during dispersion, so that the strength in the XY axis directions cannot be compensated.

Examples of the plate-like magnetic particles used in the solder resist layer include BaFe ₁₂ O ₁₉ and SrFe ₁₂ O ₁₉ . The acicular ratio of the acicular non-magnetic particles in the solder resist layer is preferably "3 to 30" (Example 12). When the acicular ratio of the acicular inorganic particles is smaller than "3", the arrangement in the solder resist is deteriorated and the strength in the XY axis directions cannot be compensated (Comparative Example 15). On the other hand, if the acicular ratio of the acicular non-magnetic particles is larger than "30", the particles will be broken during dispersion, so that the strength in the XY axis directions cannot be compensated.

Needle-like non-magnetic material used in the solder resist layer
As an example of the inorganic particles, α-Fe _Two O_Three , ZnO, Z
nSiO_Four And the like. [Third Embodiment] The following Examples 13 to 18 are
[Third Embodiment] is shown and Comparative Examples 16 to 23 are shown.
Is a comparative example necessary for evaluating [Third Embodiment]
Is shown. [Table 5] shows the material composition of each solder resist layer.
Is shown.

[0054]

[Table 5]

(Example 13) In this (Example 13), the solder resist layers 5a and 5b are composed of a composition of needle-like magnetic particles 9, plate-like non-magnetic inorganic particles 7 and a binder as shown in FIG. The following solder resist ink was used.

Epoxy acrylate resin: 40 parts by weight Acrylate monomer: 10 parts by weight Needle-like magnetic particles γ-Fe ₂ O ₃ (long axis length 0.12 μm, short axis length 0.006 μm , Ratio table area 35 m ² / g) ・ ・ ・ ・ ・ ・ 25 parts by weight Plate-like non-magnetic inorganic particles (plate diameter 0.1 μm, specific surface area 50 m ² / g, plate-like ratio 5) ・ ・ ・ ・ ・ ・25 parts by weight The above materials were mixed with a mixer, kneaded with a pressure kneader, diluted with a solvent, and then dispersed with a sand mill to obtain a predetermined solder resist ink. Next, apply the prepared solder resist ink to one side of the substrate using a screen printing machine, orient it in the undried state, and temporarily dry it.
The solder resist layer 5a was formed at 50 ° C. for 20 minutes. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, a solder resist ink was printed, orientation was applied, and then temporary drying was performed to form a solder resist layer 5b.

(Examples 14 to 16) Printed wiring boards of (Examples 14 to 16) in the same manner as (Example 13) except that the material composition of the solder resist layer was changed as shown in [Table 5]. Got

(Example 17) Example 17 was repeated except that the acicular ratio of the acicular magnetic particles in the solder resist layer was changed to "10" as shown in [Table 5] (Example 13). 17)
Was obtained.

(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 in the solder resist layer was changed.

(Comparative Examples 16 to 21) Printed wiring boards of (Comparative Examples 16 to 21) were obtained in the same manner as in (Example 13) except that the material composition of the solder resist layer was changed.

(Comparative Example 22) Comparative Example 22 (Comparative Example) except that the acicular ratio of the acicular magnetic particles in the solder resist layer was changed to "2" as shown in [Table 5]. A printed wiring board of 22) was obtained.

(Comparative Example 23) In the same manner as in (Example 13) except that the tabular ratio of the tabular non-magnetic inorganic particles of the solder resist layer was changed to "2" as shown in [Table 5] (see Example 13). A printed wiring board of Comparative Example 23) was obtained.

The performance of each printed wiring board thus obtained (the size thereof is 510 × 340 mm) was measured for the following items. The results are shown in Table 6 below. (1) Amount of warpage The amount of warpage at the four corners of the printed wiring board was measured using a ruler. (2) Electromagnetic waves Unwanted radiation was measured at 50 MHz and 150 MHz.

[0064]

[Table 6]

As is clear from the results of the above-mentioned Examples and Comparative Examples, the printed wiring board obtained by the constitution of the present invention is excellent in the amount of warpage and the unnecessary radiation of electromagnetic waves. As can be seen from this [Table 6], the compounding ratio of the acicular magnetic particles and the plate-like nonmagnetic inorganic particles in the solder resist layer to the binder is "50:50 to 20: 8 by weight".
0 "is preferred (Examples 13 and 14). When the compounding 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 solder resist layer becomes insufficient, The filling properties and dispersibility of the acicular magnetic particles and the plate-like non-magnetic inorganic particles are deteriorated (Comparative Example 1).
8). On the contrary, if it is less than 20 parts by weight, the strength in the XY axis directions cannot be compensated (Comparative Example 19).

Further, the mixing ratio of the acicular magnetic particles to the plate-like non-magnetic inorganic particles is 70:30 to 30: by weight.
70 "is preferable (Examples 15 and 16). When the mixing ratio of the acicular magnetic particles to the plate-like non-magnetic inorganic particles exceeds 70 parts by weight, crosstalk may be promoted (Comparative Example 20). On the contrary, when the amount is less than 30 parts by weight, the effectiveness against the magnetic field does not appear (Comparative Example 21).

The acicular ratio of the acicular magnetic particles in the solder resist layer is preferably "3 to 30" (Example 17). When the acicular ratio of the acicular magnetic particles is smaller than “3”, the arrangement in the solder resist is deteriorated 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 larger than "30", the particles will be broken during dispersion, so that the strength in the XY axis directions cannot be compensated.

Examples of the acicular magnetic particles used in the solder resist layer include γ-Fe ₂ O ₃ as well as CrO ₂ and C.
and o-γFe ₂ O _{3 and the} like. The plate-like ratio of the plate-like non-magnetic inorganic particles in the solder resist layer is preferably "3 to 8" (Example 18). When the plate-like ratio of the plate-like non-magnetic inorganic particles is smaller than "3", the arrangement in the solder resist is deteriorated 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, so that the strength in the XY axis directions cannot be compensated.

Plate-like non-magnetic material used in solder resist layer
As an example of the inorganic particles, α-Fe _Two O_Three Besides, clouds
Examples include mother and graphite. [Fourth Embodiment] The following Examples 19 to 24 are
[Fourth Embodiment] is shown and Comparative Examples 22 to 27 are shown.
Is a comparative example necessary for evaluating [fourth embodiment].
Is shown. [Table 7] shows the material composition of each solder resist layer.
Is shown.

[0070]

[Table 7]

(Example 19) In this (Example 19), the solder resist layers 5a and 5b are composed of needle-like magnetic particles 9, needle-like non-magnetic inorganic particles 7 and a binder as shown in FIG. The following solder resist ink was used.

Preparation of Ink for Solder Resist Layer; Epoxy Acrylate Resin ・ ・ ・ ・ ・ 40 parts by weight Acrylate monomer ・ ・ ・ ・ ・ 10 parts by weight Needle-like magnetic particles γ-Fe ₂ O ₃ (long axis length 0.12 μm , Minor axis length 0.006 μm, specific surface area 35 m ² / g) ・ ・ ・ 25 parts by weight Needle-like non-magnetic inorganic particles ZnO (major axis length 0.12 μm, minor axis length 0.006 μm, specific surface area 35 m ² / G) 25 parts by weight The above materials were mixed by a mixer, kneaded by a pressure kneader, diluted with a solvent and dispersed by a sand mill to obtain a predetermined solder resist ink. Next, apply the prepared solder resist ink to one side of the substrate using a screen printing machine, orient it in the undried state, and temporarily dry it.
The solder resist layer 5a was formed at 50 ° C. for 20 minutes. Further, the opposite surface of the substrate was shifted in the direction of 90 degrees with respect to the one surface, a solder resist ink was printed, orientation was applied, and then temporary drying was performed to form a solder resist layer 5b.

(Examples 20 to 22) Printed wiring boards of (Examples 20 to 22) were carried out in the same manner as (Example 19) except that the material composition of the solder resist layer was changed as shown in [Table 7]. Got

(Example 23) In the same manner as in Example 19 except that the acicular ratio of acicular magnetic particles in the solder resist layer was changed to "10" as shown in [Table 7] (Example 19) 23)
Was obtained.

Example 24 The acicular ratio of acicular non-magnetic inorganic particles in the solder resist layer was "1" as shown in [Table 7].
A printed wiring board of (Example 24) was obtained in the same manner as in (Example 19) except that the printed wiring board was changed to "0".

Comparative Examples 22 to 25 Printed wiring boards of (Examples 22 to 25) in the same manner as (Example 19) except that the material composition of the solder resist layer was changed as shown in [Table 7]. Got

(Comparative Example 26) Comparative Example 26 (Comparative Example) except that the acicular ratio of the acicular magnetic particles in the solder resist layer was changed to "1" as shown in [Table 7]. A printed wiring board of 26) was obtained.

(Comparative Example 27) The procedure of Example 19 was repeated except that the acicular ratio of the acicular non-magnetic inorganic particles in the solder resist layer was changed to "2" as shown in [Table 7]. A printed wiring board of Comparative Example 27) was obtained.

The performance of each printed wiring board thus obtained (its size is 510 × 340 mm) was measured for the following items. The results are shown in [Table 8] below. (1) Amount of warpage The amount of warpage at the four corners of the printed wiring board was measured using a ruler. (2) Electromagnetic waves Unwanted radiation was measured at 50 MHz and 150 MHz.

[0080]

[Table 8]

As is clear from the results of the above-mentioned Examples and Comparative Examples, the printed wiring board obtained by the constitution of the present invention is excellent in the amount of warpage and the unnecessary radiation of electromagnetic waves. As can be seen from [Table 8], the mixing ratio of the acicular magnetic particles and acicular non-magnetic inorganic particles in the solder resist layer to the binder is 50:50 to 20: 8 by weight.
0 "is preferable (Examples 19 and 20).

When the compounding ratio of the acicular magnetic particles and acicular non-magnetic inorganic particles to the binder exceeds 50 parts by weight, the binder in the solder resist layer becomes insufficient, resulting in acicular magnetic particles and acicular non-magnetic inorganic particles. The filling property and the dispersibility of are decreased (Comparative Example 22). On the contrary, if less than 20 parts by weight, XY
It becomes impossible to supplement the strength in the axial direction (Comparative Example 2).
3).

Further, the mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles is in the range of 70:30 to 3 by weight.
0:70 "is preferable (Examples 21 and 22). The mixing ratio of the acicular magnetic particles to the acicular non-magnetic inorganic particles is 7
If it exceeds 0 part by weight, crosstalk may be promoted (Comparative Example 24). On the contrary, when the amount is less than 30 parts by weight, the effectiveness against the magnetic field does not appear (Comparative Example 25).

The acicular ratio of the acicular magnetic particles in the solder resist layer is preferably "3 to 30" (Example 23). When the acicular ratio of the acicular magnetic particles is smaller than “3”, the arrangement in the solder resist is deteriorated 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 will be broken during dispersion, so that the strength in the XY axis directions cannot be compensated.

Examples of needle-like magnetic particles used in the solder resist layer include γ-Fe ₂ O ₃ , CrO ₂ and Co.
-ΓFe ₂ O _{3 and the} like can be mentioned. As an example of the acicular non-magnetic inorganic particles used in the solder resist layer, ZnO is used.
In addition, α-Fe ₂ O ₃ and ZnSiO ₄ may be used.

[0086]

As described above, according to the present invention, by forming a solder resist layer in which plate-shaped or needle-shaped magnetic particles, non-magnetic inorganic particles and a binder are arranged on the front and back sides of a multilayer substrate. It is possible to reduce warpage that occurs after manufacturing the multilayer substrate. Further, since the solder resist layer contains magnetic particles, it is possible to provide a printed wiring board effective against electromagnetic fields against electromagnetic interference.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a four-layer board in each embodiment.

FIG. 2 is an explanatory diagram of a solder resist layer according to the first embodiment.

FIG. 3 is an explanatory diagram of a solder resist layer according to the second embodiment.

FIG. 4 is an explanatory diagram of a solder resist layer according to a third embodiment.

FIG. 5 is an explanatory diagram of a solder resist layer according to a fourth embodiment.

[Explanation of symbols]

 4 4-layer substrate 5a, 5b Solder resist layer 6 Plate-shaped magnetic particles 7 Plate-shaped non-magnetic inorganic particles 8 Needle-shaped non-magnetic inorganic particles 9 Needle-shaped magnetic particles

Claims (12)

[Claims] 1. A printed wiring board, characterized in that a solder resist layer having plate-shaped magnetic particles, plate-shaped non-magnetic particles and a binder is formed on the front and back surfaces of a multilayer substrate. 2. The compounding ratio of the plate-shaped magnetic particles and the plate-shaped non-magnetic inorganic particles in the solder resist layer to the binder is
The weight ratio of "50:50 to 20:80", and the compounding ratio of the plate-like magnetic particles to the plate-like non-magnetic inorganic particles is "70:30 to 30:70" by weight ratio. Item 1
The printed wiring board as described. 3. A solder resist layer having plate-like magnetic particles, acicular non-magnetic inorganic particles and a binder is formed on the front and back surfaces of the multilayer substrate, and the solder resist layers on the front and back surfaces of the multilayer substrate are oriented in a 90 ° direction, respectively. A printed wiring board characterized by being staggered and applied. 4. The compounding ratio of the plate-like magnetic particles and the acicular non-magnetic inorganic particles in the solder resist layer to the binder is
The weight ratio of "50:50 to 20:80", and the compounding ratio of the plate-like magnetic particles to the acicular non-magnetic inorganic particles is "70:30 to 30:70" by weight ratio. Item 3. The printed wiring board according to item 3. 5. A printed wiring board, characterized in that a solder resist having needle-shaped magnetic particles, plate-shaped non-magnetic inorganic particles, and a binder arranged on the front and back sides of a multi-layered substrate, respectively, shifted in the direction of 90 degrees, is formed. . 6. The compounding ratio of the acicular magnetic particles and the plate-like non-magnetic inorganic particles in the solder resist layer to the binder is
A weight ratio of "50:50 to 20:80", and a mixing ratio of acicular magnetic particles to plate-like non-magnetic inorganic particles is "70:30 to 30:70" by weight ratio. Item 5
The printed wiring board as described. 7. A printed wiring characterized in that a solder resist layer, in which needle-like magnetic particles and needle-like non-magnetic inorganic particles and binders, which are oriented by being shifted in a direction of 90 degrees, are arranged on the front and back surfaces of a multilayer substrate, respectively. Board. 8. The compounding ratio of the acicular magnetic particles and acicular non-magnetic inorganic particles in the solder resist layer to the binder is
A weight ratio of "50:50 to 20:80", and a mixing ratio of acicular magnetic particles to acicular non-magnetic inorganic particles is "70:30 to 30:70" by weight ratio. Item 7. A printed wiring board according to item 7. 9. The printed wiring board according to claim 1, wherein the plate-shaped magnetic particles have a plate-shaped ratio of “3 to 8”. 10. The printed wiring board according to claim 1, wherein the plate-like inorganic particles have a plate-like ratio of “3 to 8”. 11. The acicular ratio "3 to 30" of acicular inorganic particles.
The printed wiring board according to claim 3, wherein the printed wiring board is a printed wiring board. 12. The printed wiring board according to claim 5, wherein the acicular magnetic particles have an acicular ratio of “3 to 30”.