JP2021136272A - Magnetic sheet - Google Patents

Abstract

To provide a magnetic sheet improved in the easiness of dicing a magnetic layer into pieces, a production method thereof, a circuit board and inductor substrate which are obtained by use of the magnetic sheet, and a production method of the circuit board.SOLUTION: A magnetic sheet comprises: a support body; and a plurality of magnetic layers provided on the support body so as to be apart from each other. The plurality of magnetic layers include cured products of a resin composition containing magnetic powder.SELECTED DRAWING: Figure 2

Description

The present invention relates to a magnetic sheet, a method for manufacturing the same, and a circuit board, an inductor board, and a method for manufacturing a circuit board obtained by using the magnetic sheet.

Parts containing magnetic powder, such as inductor parts and magnetic shields, may be mounted on circuit boards such as printed wiring boards. Conventionally, such parts are often manufactured using a mold (Patent Document 1).

Japanese Unexamined Patent Publication No. 2003-28234

Manufacture using a mold is generally time consuming and costly. Therefore, the present inventors have studied a new manufacturing technique for parts that does not use a mold. Specifically, a large-area magnetic layer can be produced using a resin composition containing magnetic powder, and the large-area magnetic layer can be cut into individual pieces and used as a part or a part thereof. Attempts have been made to obtain a magnetic layer of appropriate size.

However, since the magnetic layer contains magnetic powder, it is generally hard and highly brittle. In particular, in order to improve the magnetic properties of the magnetic layer, it is required to contain a large amount of magnetic powder, so that it tends to be harder and more brittle. Therefore, it was difficult to cut the magnetic layer having a large area. Further, even if it can be cut, the obtained magnetic layer may be cracked. Under these circumstances, it has been difficult to easily manufacture an individualized magnetic layer.

The present invention has been made in view of the above circumstances, and is a magnetic sheet having improved ease of individualization of a magnetic layer, a method for manufacturing the magnetic sheet, and a circuit board and an inductor board obtained by using the magnetic sheet. And a method for manufacturing a circuit board.

That is, the present invention includes the following contents.
[1] Support and
The support has a plurality of magnetic layers provided apart from each other, and has a plurality of magnetic layers.
The plurality of magnetic layers are magnetic sheets containing a cured product of a resin composition containing magnetic powder.
[2] The magnetic sheet according to [1], wherein the thickness of each magnetic layer is 0.01 mm or more and 0.5 mm or less.
[3] The magnetic sheet according to [1] or [2], wherein the width in the longitudinal direction and the lateral direction of each magnetic layer is 0.5 mm or more and 10 mm or less.
[4] The magnetic sheet according to any one of [1] to [3], wherein the minimum distance between the magnetic layers is 0.1 mm or more and 20 mm or less.
[5] The magnetic sheet according to any one of [1] to [4], which is used for manufacturing a circuit board.
[6] A circuit board including the magnetic layer of the magnetic sheet according to any one of [1] to [5].
[7] An inductor substrate including the circuit board according to [6].
[8] (1) The step of preparing the magnetic sheet according to any one of [1] to [5].
A method for manufacturing a circuit board, which comprises (2) a step of peeling off a support and (4) a step of joining a magnetic layer to an inner layer substrate.
[9] Between steps (2) and (4),
(3) The method for manufacturing a circuit board according to [8], which includes a step of supplying a magnetic layer to a mounter.
[10] The process includes (A) printing a resin composition containing a magnetic powder on the support to form a plurality of resin composition layers, and (B) curing the resin composition layer. Manufacturing method of magnetic sheet.
[11] The method for manufacturing a magnetic sheet according to [10], wherein the printing is screen printing.

According to the present invention, there is provided a magnetic sheet having improved ease of individualization of a magnetic layer, a method for manufacturing the same, and a circuit board, an inductor board, and a method for manufacturing a circuit board obtained by using the magnetic sheet. Can be done.

FIG. 1 is, as an example, a schematic perspective view of a sheet in which a resin composition is printed on a support. FIG. 2 is a schematic perspective view of a magnetic sheet as an example. FIG. 3 is a schematic perspective view showing a reel for supplying a magnetic layer as an example to a mounter. FIG. 4 is a schematic cross-sectional view showing a state in which a magnetic layer as an example is bonded to an inner layer substrate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing merely outlines the shape, size and arrangement of the components so that the invention can be understood. The present invention is not limited to the following embodiments, and each component can be changed as appropriate. Further, the configuration according to the embodiment of the present invention is not always manufactured or used by the arrangement of the illustrated examples.

[Magnetic sheet]
The magnetic sheet of the present invention has a support and a plurality of magnetic layers provided on the support so as to be separated from each other, and the plurality of magnetic layers are cured of a resin composition containing magnetic powder. Including things.

FIG. 2 is a schematic perspective view of a magnetic sheet as an example. The magnetic sheet 1 shown in FIG. 2 includes a plurality of magnetic layers 3 provided on the support 2 so as to be separated from each other. Since the magnetic layer 3 of the magnetic sheet 1 has already been individualized, the individualized magnetic layer 3 can be obtained only by peeling off the support 2. The shape of the magnetic sheet 1 is arbitrary, but is usually a quadrangle.

The width a of each magnetic layer 3 in the longitudinal direction is preferably 0.5 mm or more, more preferably 1 mm or more, further preferably 2 mm or more, and preferably 10 mm or less from the viewpoint of producing a miniaturized circuit board. , More preferably 8 mm or less, still more preferably 6 mm or less.

The width b of each magnetic layer 3 in the lateral direction is preferably 0.5 mm or more, more preferably 1 mm or more, further preferably 2 mm or more, and preferably 10 mm from the viewpoint of producing a miniaturized circuit board. Below, it is more preferably 8 mm or less, still more preferably 6 mm or less.

The minimum distance c between the magnetic layers 3 is preferably 0.1 mm or more, more preferably 0.5 mm or more, still more preferably 1 mm or more, from the viewpoint of facilitating individualization of the plurality of magnetic layers 3. It is preferably 20 mm or less, more preferably 15 mm or less, still more preferably 10 mm or less.

The thickness of the magnetic layer 3 is preferably 0.5 mm or less, more preferably 0.3 mm or less, still more preferably 0.1 mm or less, preferably 0.01 mm or more, and more preferably 0, from the viewpoint of thinning. It is .03 mm or more, more preferably 0.05 mm or more.

Hereinafter, each layer constituting the magnetic sheet of the present invention will be described in detail.

<Support>
The magnetic sheet has a support. Examples of the support include a film made of a plastic material, a metal foil, and a paper pattern, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, the plastic material may be, for example, polyethylene terephthalate (hereinafter, may be abbreviated as "PET") or polyethylene naphthalate (hereinafter, abbreviated as "PEN"). ) And other polyesters, polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic polymers such as polymethylmethacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyethersulfide (PES), poly. Examples thereof include ether ketone and polyethylene. Of these, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

When a metal foil is used as the support, examples of the metal foil include copper foil, aluminum foil, and the like, and copper foil is preferable. As the copper foil, a foil made of a single metal of copper may be used, and a foil made of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. You may use it.

The support may be matted or corona-treated on the surface to be joined to the resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be joined with the magnetic layer may be used. Examples of the release agent used for the release layer of the support with the release layer include one or more release agents selected from the group consisting of alkyd resin, polyolefin resin, urethane resin, and silicone resin. .. A commercially available product may be used as the support with a release layer.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably in the above range.

<Magnetic layer>
The magnetic sheet has a magnetic layer containing a cured product of a resin composition containing magnetic powder. A plurality of magnetic layers are provided so as to be separated from each other. A plurality of magnetic layers are bonded to a support, and when manufacturing a circuit board or the like, the plurality of magnetic layers are separated and used. As such a resin composition, for example, it is preferable that the cured product has sufficient hardness and relative magnetic permeability. Hereinafter, each component contained in the resin composition will be described in detail.

-Magnetic powder-
The resin composition contains a magnetic powder. By including the magnetic powder in the resin composition, it is possible to improve the relative magnetic permeability of the magnetic layer. The magnetic powder may be used alone or in combination of two or more.

The magnetic powder may be either a soft magnetic powder or a hard magnetic powder, but is preferably a soft magnetic powder from the viewpoint of improving the relative magnetic permeability.

Examples of the magnetic powder include Fe-Mn-based ferrite, Fe-Mn-Zn-based ferrite, Mg-Zn-based ferrite, Mn-Zn-based ferrite, Mn-Mg-based ferrite, Cu-Zn-based ferrite, and Mg-Mn-. Sr-based ferrite, Ni-Zn-based ferrite, Ba-Zn-based ferrite, Ba-Mg-based ferrite, Ba-Ni-based ferrite, Ba-Co-based ferrite, Ba-Ni-Co-based ferrite, Y-based ferrite, iron oxide powder ( III), Iron oxide powder such as triiron tetroxide; Pure iron powder; Fe-Si based alloy powder, Fe-Si-Al alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy powder, Fe −Ni—Cr alloy powder, Fe—Cr—Al alloy powder, Fe—Ni alloy powder, Fe—Ni—Mo alloy powder, Fe—Ni—Mo—Cu alloy powder, Fe—Co alloy powder , Or iron alloy-based metal powder such as Fe—Ni—Co-based alloy powder; amorphous alloys such as Co-based amorphous, and the like.

Among them, the magnetic powder is preferably at least one selected from iron oxide powder and iron alloy-based metal powder. The iron oxide powder preferably contains a ferrite containing at least one selected from Ni, Cu, Mn, and Zn, and is preferably at least one selected from Fe-Mn-based ferrite and Fe-Mn-Zn-based ferrite. More preferably. Further, the iron alloy-based metal powder preferably contains an iron alloy-based metal powder containing at least one selected from Si, Cr, Al, Ni, and Co. Further, as the magnetic powder, a commercially available product may be used.

The magnetic powder is preferably spherical. The value (aspect ratio) obtained by dividing the length of the major axis of the magnetic powder by the length of the minor axis is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2 or less. In general, it is easier to improve the relative magnetic permeability when the magnetic powder has a flat shape that is not spherical. However, it is usually preferable to use a spherical magnetic powder from the viewpoint of obtaining a resin composition having a preferable viscosity and a low magnetic loss.

The average particle size of the magnetic powder is preferably 0.01 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, from the viewpoint of improving the relative magnetic permeability. Further, it is preferably 30 μm or less, more preferably 25 μm or less, and further preferably 20 μm or less.

The average particle size of the magnetic powder can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of magnetic powder on a volume basis with a laser diffraction / scattering type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, a magnetic powder dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction / scattering type particle size distribution measuring device, "LA-960" manufactured by HORIBA, Ltd., "SALD-2200" manufactured by Shimadzu Corporation, or the like can be used.

The specific surface area of the magnetic powder, from the viewpoint of improving the relative permeability, preferably 0.05 m ² / g or more, more preferably 0.1 m ² / g or more, even more preferably at 0.3 m ² / g or more .. Further, it is preferably 10 m ² / g or less, more preferably 8 m ² / g or less, and further preferably 5 m ² / g or less. The specific surface area of the magnetic powder can be measured by the BET method.

The magnetic powder may be treated with a surface treatment agent from the viewpoint of adjusting the viscosity of the resin composition and further enhancing the moisture resistance and dispersibility. Examples of the surface treatment agent include vinylsilane-based coupling agents, (meth) acrylic-based coupling agents, fluorine-containing silane coupling agents, aminosilane-based coupling agents, epoxysilane-based coupling agents, and mercaptosilane-based coupling agents. Examples thereof include silane-based coupling agents, alkoxysilanes, organosilazane compounds, and titanate-based coupling agents. One type of surface treatment agent may be used alone, or two or more types may be used in any combination. Moreover, you may use a commercially available product as a surface treatment agent.

The degree of surface treatment with the surface treatment agent is preferably within a predetermined range from the viewpoint of improving the dispersibility of the magnetic powder. Specifically, 100 parts by mass of the magnetic powder is preferably surface-treated with 0.01 parts by mass to 5 parts by mass of a surface treatment agent, and is surface-treated with 0.05 parts by mass to 3 parts by mass. It is preferable that the surface is treated with 0.1 parts by mass to 2 parts by mass.

The content (volume%) of the magnetic powder is preferably 40% by volume or more, more preferably 50% by volume or more when the non-volatile component in the resin composition is 100% by volume from the viewpoint of improving the relative magnetic permeability. , More preferably 60% by volume or more. Further, it is preferably 85% by volume or less, more preferably 80% by volume or less, and further preferably 70% by volume or less.

The content (mass%) of the magnetic powder is preferably 60% by mass or more, more preferably 70% by mass or more, when the non-volatile component in the resin composition is 100% by mass from the viewpoint of improving the relative magnetic permeability. , More preferably 75% by mass or more. Further, it is preferably 98% by mass or less, more preferably 95% by mass or less, and further preferably 90% by mass or less. In the present invention, the content of each component in the resin composition is a value when the non-volatile component in the resin composition is 100% by mass, unless otherwise specified.

-Curable resin-
The resin composition may contain a curable resin as an optional component. Examples of the curable resin include thermosetting resins and photocurable resins, but thermosetting resins are preferable. As such a thermosetting resin, for example, an epoxy resin is preferable.

The epoxy resin is, for example, glycyrrole type epoxy resin; bisphenol A type epoxy resin; bisphenol F type epoxy resin; bisphenol S type epoxy resin; bisphenol AF type epoxy resin; dicyclopentadiene type epoxy resin; trisphenol type epoxy resin; phenol novolac. Type epoxy resin; tert-butyl-catechol type epoxy resin; naphthol novolac type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin and other epoxy resins having a fused ring structure; glycidylamine type epoxy resin; glycidyl Ester type epoxy resin; Cresol novolac type epoxy resin; Biphenyl type epoxy resin; Linear aliphatic epoxy resin; Epoxy resin having a butadiene structure; Alicyclic epoxy resin; Heterocyclic epoxy resin; Spiro ring-containing epoxy resin; Cyclohexanedi Methanol type epoxy resin; trimethylol type epoxy resin; tetraphenylethane type epoxy resin and the like can be mentioned. The epoxy resin may be used alone or in combination of two or more. The epoxy resin may be used alone or in combination of two or more. Further, as the epoxy resin, a commercially available product may be used.

The epoxy resin may be a liquid epoxy resin at a temperature of 25 ° C. (hereinafter sometimes referred to as “liquid epoxy resin”) or a solid epoxy resin at a temperature of 25 ° C. (hereinafter referred to as “solid epoxy resin”). ). The epoxy resin may contain only a liquid epoxy resin, may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin.

The epoxy equivalent of the epoxy resin is preferably 50 g / eq. ~ 5000 g / eq. , More preferably 50 g / eq. ~ 3000 g / eq. , More preferably 80 g / eq. ~ 2000 g / eq. , Even more preferably 110 g / eq. ~ 1000 g / eq. Is. Within this range, the crosslink density of the cured product becomes sufficient, and a magnetic layer having a small surface roughness can be provided. The epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of the epoxy group.

The weight average molecular weight of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method.

In addition to epoxy resins, thermosetting resins include phenolic resins, naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins. As described above, it may contain a component that can react with the epoxy resin to cure the resin composition.

The content of the curable resin is preferably 1% by mass or more, more preferably 5% by mass, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of obtaining a cured product having excellent mechanical properties and magnetic properties. Above, more preferably 10% by mass or more. The upper limit is not particularly limited as long as the effect of the present invention is exhibited, but is preferably 30% by mass or less, more preferably 25% by mass or less, and further preferably 20% by mass or less.

-Dispersant-
The resin composition may further contain a dispersant as an optional component. Examples of the dispersant include phosphate ester dispersants such as polyoxyethylene alkyl ether phosphoric acid; anionic dispersants such as sodium dodecylbenzel sulfonate, sodium laurylate, and ammonium salts of polyoxyethylene alkyl ether sulfate; Organosiloxane-based dispersant, polyoxyalkylene-based dispersant, acetylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxy Examples thereof include nonionic dispersants such as ethylene alkyl amide. Of these, nonionic dispersants are preferred. The dispersant may be used alone or in combination of two or more. Moreover, you may use a commercially available product as a dispersant.

The content of the dispersant is preferably 0.1% by mass or more, more preferably 0.3% by mass, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of remarkably exerting the effect of the present invention. % Or more, more preferably 0.5% by mass or more, and the upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less.

-Curing accelerator-
The resin composition may further contain a curing accelerator as an optional component. Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like, and phosphorus-based curing accelerators and amine-based curing accelerators. Curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are preferable, amine-based curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are more preferable, and imidazole-based curing accelerators are even more preferable. The curing accelerator may be used alone or in combination of two or more. Moreover, you may use a commercially available product as a curing accelerator.

The content of the curing accelerator is preferably 0.1% by mass or more, more preferably 0.3% by mass, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of obtaining a cured product having better mechanical properties. % Or more, more preferably 0.5% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less.

-Other additives-
The resin composition may further contain any additive, if desired. Examples of such other additives include thermoplastic resins such as phenoxy resins, flame retardants, organometallic compounds, organometallic compounds such as organozinc compounds and organocobalt compounds, and thickeners, defoaming agents, and leveling. Examples thereof include agents, adhesion-imparting agents, and resin additives such as colorants.

The resin composition can be produced, for example, by a method of stirring the compounding components using a stirring device such as a three-roll or rotary mixer.

<Other layers>
The magnetic sheet may be provided with any layer in combination with the support and the magnetic layer. For example, in the magnetic sheet, a protective film similar to the support can be further laminated on the surface of the magnetic layer that is not bonded to the support (that is, the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress adhesion of dust and the like to the surface of the magnetic layer and scratches. The magnetic sheet can be rolled up and stored.

[Manufacturing method of magnetic sheet]
The method for producing a magnetic sheet of the present invention is a step of printing a resin composition containing magnetic powder on a support (A) to form a plurality of resin composition layers, and (B) a resin composition layer. Including the step of curing.

<(A) step>
The step (A) is a step of printing the resin composition on the support to form the resin composition layer. The resin composition is as described above.

FIG. 1 is a perspective view schematically showing an example of a sheet 1A in which a resin composition layer 4 is formed on a support 2. The sheet 1A is obtained by printing the resin composition on the support 2 so that the plurality of resin composition layers 4 are provided apart from each other. The width of the resin composition layer 4 in the longitudinal direction, the width of the resin composition layer 4 in the lateral direction, and the minimum distance between the resin composition layers 4 are the width a of the magnetic layer in the longitudinal direction and the width of the magnetic layer in the lateral direction. This is the same as the width b and the minimum distance c between the magnetic layers.

As a printing method of the resin composition, screen printing is usually performed, but other methods may be used. Examples of other printing methods include a method of printing a resin composition by mask printing, a method of printing by intermittent coating, a roll coating method, an inkjet method, and the like.

In the step (A), for example, a resin varnish containing a resin composition in an organic solvent is prepared, and the resin varnish is printed on the support 2 and further dried to form the resin composition layer 4. It may include forming. When the resin composition is in the form of a paste, the resin composition layer 4 can be formed by printing the resin composition directly on the support 2.

Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone (MEK) and cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and butyl carbitol and the like. Carbitols, aromatic hydrocarbons such as toluene and xylene, and amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone can be mentioned. The organic solvent may be used alone or in combination of two or more.

Drying may be carried out by a method such as heating or blowing hot air. The drying conditions are not particularly limited, but the resin varnish is dried so that the content of the organic solvent is 10% by mass or less, preferably 5% by mass or less. Although it depends on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing 30% by mass to 60% by mass of an organic solvent is used, the resin composition is obtained by drying at 50 ° C. to 150 ° C. for 3 to 10 minutes. The material layer 4 can be formed.

<(B) process>
The step (B) is a step of curing the resin composition layer 4, and the magnetic layer 3 is formed as shown in FIG. 2 by curing the resin composition layer 4. When the resin composition contains a thermosetting resin, it is preferable that the resin composition layer 4 is cured by heat curing in the step (B).

The curing conditions of the resin composition layer 4 differ depending on the composition and type of the resin composition, but the curing temperature is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, still more preferably 80 ° C. or higher, preferably 200 ° C. or higher. ° C. or lower, more preferably 190 ° C. or lower, still more preferably 180 ° C. or lower. The curing time of the resin composition layer 4 is preferably 2 minutes or more, more preferably 5 minutes or more, further preferably 8 minutes or more, preferably 120 minutes or less, more preferably 100 minutes or less, still more preferably 90 minutes. It is as follows.

Before the resin composition layer 4 is thermally cured, the resin composition layer 4 may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition layer 4, the resin composition layer is at a temperature of 50 ° C. or higher and lower than 120 ° C. (preferably 60 ° C. or higher and 115 ° C. or lower, more preferably 70 ° C. or higher and 110 ° C. or lower). 4 may be preheated for 5 minutes or longer (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, still more preferably 15 minutes to 100 minutes).

The degree of curing of the magnetic layer 3 after the step (B) is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more. The lower limit of the degree of curing can be 100% or less, 99% or less, and the like. The degree of curing can be measured using, for example, a differential scanning calorimetry device.

<Use and physical properties of magnetic layer>
Since the magnetic layer contains magnetic powder, it exhibits a characteristic of high relative magnetic permeability. Therefore, the magnetic layer of the magnetic sheet of the present invention can be suitably used for manufacturing a circuit board. Specifically, it can be suitably used as a magnetic layer of a magnetic sheet for manufacturing an inductor substrate for manufacturing an inductor substrate. Further, the magnetic layer of the magnetic sheet may be used for magnetic shielding.

The magnetic layer usually exhibits a characteristic of high relative magnetic permeability at a frequency of 100 MHz. The relative magnetic permeability of this magnetic layer at a frequency of 100 MHz is preferably 3 or more, more preferably 4 or more, and further preferably 5 or more. The upper limit is not particularly limited, but may be 20 or less.

The magnetic layer usually exhibits a characteristic of low magnetic loss at a frequency of 100 MHz. The magnetic loss of this magnetic layer at a frequency of 100 MHz is preferably 1 or less, more preferably 0.5 or less, still more preferably 0.2 or less. The lower limit is not particularly limited, but may be 0.001 or more.

The relative magnetic permeability and the magnetic loss can be measured as follows. A toroidal type magnetic layer having an outer diameter of 20 mmφ and an inner diameter of 9 mmφ is prepared and used as an evaluation sample. This evaluation sample was sampled using "16454A" manufactured by Keysight Technology Co., Ltd., with a measurement frequency in the range of 1 MHz to 3 GHz, and a specific magnetic permeability (μ') and magnetic loss (μ'') at room temperature of 23 ° C. ) Is measured. The loss factor is calculated from the following formula.
tan δ = μ'' / μ'

[Circuit board and its manufacturing method]
The circuit board of the present invention includes a magnetic layer of a magnetic sheet. The circuit board can be manufactured by, for example, using a magnetic sheet by a method including the following steps (1), (2), and (4). The following steps (1), (2), and (4) are preferably performed in this order.
(1) Step of preparing a magnetic sheet (2) Step of peeling off the support (4) Step of joining the magnetic layer to the inner layer substrate

The circuit board manufacturing method preferably includes the following step (3) between the steps (2) and (4).
(3) Step of supplying the magnetic layer to the mounter

Hereinafter, the above steps (1) to (4) in manufacturing the circuit board will be described in detail.

<(1) Step>
The step (1) is a step of preparing a magnetic sheet. The magnetic sheet is as described above.

<(2) Step>
The step (2) is a step of peeling off the support of the magnetic sheet. By peeling off the support, a plurality of magnetic layers are separated into individual pieces.

When the magnetic sheet is in the form of a roll, the support may be peeled off while transporting the magnetic sheet. Further, for example, when the magnetic sheet is a single sheet, the support may be peeled off by using a peeling device or the like that peels off the support.

<(3) Step>
The step (3) is a step of supplying each individualized magnetic layer to the mounter. By supplying the magnetic layer to the mounter, the step (4) described later can be efficiently performed by using the mounter.

FIG. 3 is a schematic perspective view showing a reel for supplying a magnetic layer as an example to a mounter. A pullable tape 51 is stored in the reel 5. Each magnetic layer 3 separated by peeling off the support in the step (2) is placed on the tape 51 of the reel 5. (3) As one embodiment of the step, the tape 51 stored in the reel 5 is pulled out, and the magnetic layers 3 separated from the head of the tape 51 are attached to the tape 51 at predetermined intervals. After that, the supply of the magnetic layer 3 to the mounter is achieved by storing the tape 51 on which the individualized magnetic layer 3 is placed in the reel 5.

<(4) Step>
The step (4) is a step of joining the magnetic layer to the inner layer substrate. A circuit board is formed by laminating and joining the magnetic layer 3 on the inner layer substrate 100. Further, when the step (3) is included, a circuit board may be formed by laminating and joining the magnetic layer 3 on the inner layer substrate 100 via a mounter. In a preferred embodiment of the step (4), the circuit board is an inductor substrate, and a conductor layer (not shown) is spirally formed on the surface of the inner layer substrate 100 so as to cover the entire conductor layer. The magnetic layer 3 is joined.

The inner layer substrate 100 is an insulating substrate. Examples of the material of the inner layer substrate include an insulating substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The inner layer board may be an inner layer circuit board in which wiring or the like is built in the thickness thereof.

Examples of the conductor material that can form the conductor layer include single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium; gold and platinum. , Palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and alloys of two or more metals selected from the group of indium. Above all, from the viewpoint of versatility, cost, ease of patterning, etc., it is possible to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloy, copper nickel alloy, copper titanium alloy. It is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, and it is even more preferable to use copper.

The bonding between the magnetic layer 3 and the inner layer substrate 100 can be performed, for example, by heat-bonding the magnetic layer 3 to the inner layer substrate 100. Examples of the member for heat-pressing the magnetic layer 3 to the inner layer substrate 100 (hereinafter, also referred to as “heat-bonding member”) include a heated metal plate (stainless steel (SUS) end plate and the like), a metal roll (SUS roll), and the like. Can be mentioned. Instead of pressing the heat-bonded member in direct contact with the magnetic layer 3, a sheet or the like made of an elastic material such as heat-resistant rubber so that the magnetic layer 3 sufficiently follows the unevenness of the surface of the inner layer substrate 100. It is preferable to press through.

The temperature during heat crimping is preferably in the range of 80 ° C. to 160 ° C., more preferably 90 ° C. to 140 ° C., still more preferably 100 ° C. to 120 ° C., and the pressure during heat crimping is preferably 0. It is in the range of 098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, and the time for heat crimping is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The bonding between the magnetic layer 3 and the inner layer substrate 100 is preferably carried out under reduced pressure conditions of a pressure of 26.7 hPa or less.

Further, the magnetic layer 3 and the inner layer substrate 100 can be joined by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressurizing laminators manufactured by Meiki Co., Ltd., vacuum applicators manufactured by Nikko Materials, and the like. Further, the magnetic layer 3 and the inner layer substrate 100 can be joined by using a commercially available adhesive.

After joining the magnetic layer 3 and the inner layer substrate 100, the laminated magnetic layer 3 is smoothed by pressing a heat-bonded member under normal pressure (under atmospheric pressure), for example, from the magnetic layer 3 side. May be good. The press conditions for the smoothing treatment can be the same as the heat-bonding conditions for the above-mentioned lamination. The smoothing process can be performed by a commercially available laminator. The lamination and the smoothing treatment may be continuously performed using the above-mentioned commercially available vacuum laminator.

[Inductor board]
The inductor substrate includes the circuit board of the present invention. Such an inductor substrate has an inductor pattern formed by a conductor at least a part around the magnetic layer. As such an inductor substrate, for example, those described in JP-A-2016-197624 can be applied.

The inductor substrate can be used as a wiring board for mounting an electronic component such as a semiconductor chip, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer substrate. Further, the wiring board can be used as an individualized chip inductor component, or the chip inductor component can be used as a surface-mounted printed wiring board.

Further, various types of semiconductor devices can be manufactured by using such a wiring board. The semiconductor device including such a wiring plate can be suitably used for electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircraft, etc.) and the like. ..

1 Magnetic sheet 1A Sheet 2 Support 3 Magnetic layer 4 Resin composition layer 5 Reel 51 Tape 100 Inner layer substrate a Longitudinal width of magnetic layer b Width of magnetic layer in short direction c Minimum distance between magnetic layers

Claims (11)

With the support
The support has a plurality of magnetic layers provided apart from each other, and has a plurality of magnetic layers.
The plurality of magnetic layers are magnetic sheets containing a cured product of a resin composition containing magnetic powder. The magnetic sheet according to claim 1, wherein the thickness of each magnetic layer is 0.01 mm or more and 0.5 mm or less. The magnetic sheet according to claim 1 or 2, wherein the width in the longitudinal direction and the lateral direction of each magnetic layer is 0.5 mm or more and 10 mm or less. The magnetic sheet according to any one of claims 1 to 3, wherein the minimum distance between the magnetic layers is 0.1 mm or more and 20 mm or less. The magnetic sheet according to any one of claims 1 to 4, which is used for manufacturing a circuit board. A circuit board comprising the magnetic layer of the magnetic sheet according to any one of claims 1 to 5. An inductor substrate including the circuit board according to claim 6. (1) A step of preparing the magnetic sheet according to any one of claims 1 to 5.
A method for manufacturing a circuit board, which comprises (2) a step of peeling off a support and (4) a step of joining a magnetic layer to an inner layer substrate. Between steps (2) and (4),
(3) The method for manufacturing a circuit board according to claim 8, further comprising a step of supplying a magnetic layer to a mounter. A magnetic sheet containing (A) a step of printing a resin composition containing magnetic powder on a support to form a plurality of resin composition layers, and (B) a step of curing the resin composition layers. Production method. The method for manufacturing a magnetic sheet according to claim 10, wherein the printing is screen printing.

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